Patents Q&A

What Are Common Mistakes in Design Patent Applications?

There are certain requirements and interpretive frameworks that apply U.S. design patent applications that may not be intuitive. Many of these U.S. standards also differ significantly from the rules the apply to industrial design registrations in other countries. What follows is a guide to some common mistakes and misunderstandings around design patents and applications.

Additional information about acceptable practices for design patent applications can be found in the U.S. Patent & Trademark Office’s (USPTO’s) design patent application guide and in the Manual of Patent Examining Procedure (MPEP) Chapter 1500.

“Engineering” Style Drawings Treated Unfavorably

Designers may create computer-aided drafting (CAD) drawings to document their designs. These often follow engineering conventions, including the use of “tangent” lines to show the boundaries of a curved surface. However, U.S. design patent practice relies on the use of surface shading lines or stippling . This is any entirely different style and approach than familiar engineering standards.

Shading lines or stippling that contrast with the rest of a drawing are used to show curves, tapers, and other three-dimensional (3D) contours in design patent drawings. The arrangement and spacing of straight shading lines is commonly used to indicate the character of curvature or contouring. Shading lines that are not straight may also be permissible. Surface shading lines can be broken/discontinuous and light/thin to differentiate them from lines indicating surface ornamentation and/or the ornamental shape of an article itself. They must be used sparingly, with as few in number as practicable.

Other characteristics can also be represented by shading lines. For instance, equally spaced shading lines arranged parallel to each other are used to indicate flat surfaces. Shading lines or stippling can be used to distinguish open areas (like holes) from solid material as well. Also, light, full shading lines indicate transparent materials.

The following is an example used in the USPTO’s design patent application guide to illustrate straight, parallel shading lines with their spacing using to show curved edges of a sink. These shading or contour lines are discontinuous, each having a long unbroken segment plus a short, dot-like segment slightly spaced from an end of the long segment. In this example, other discontinuous shading lines are used to illustrate flat surfaces too.

Drawing of a sink showing use of spaced, straight shading lines in design patents
USPTO example of use of shading lines in design application drawings

The following is an example of non-linear (curved) shading lines used to illustrate 3D curvature of a vehicle mirror. These shading or contour lines are discontinuous to distinguish them. These types of shading lines are appropriate for illustrating more complex 3D shapes. In this example, broken (dashed) line(s) further illustrate the boundary of the claimed design, meaning that only a portion of the depicted article is part of this claimed design.

FIG. 1 of U.S. Pat. D427,554, showing use of shading lines to illustrate 3D contours of a vehicle mirror
FIG. 1 of U.S. Pat. No. D427,554

The following examples are drawn from a case about alleged infringement of two design patents covering a trash can and a recycling bin. Red arrows indicate lines whose meaning was disputed by the parties. The court construed the patents’ engineering-style drawings with curvature boundary tangent lines to mean visible ornamentation in the form of seams, paint, or something else that appears as actual lines on the trash can or recycling bin rather than merely conveying the boundaries of 3D contours where they transition to flat surfaces.

Annotated views with red arrows and blue circles labeling disputed lines in two trash can/recycling bin design patents
Annotated verisons of FIG. 1 of U.S. Pat. No. D644,807 for a “Slim Open Trash Can” (left) and FIG. 1 of U.S. Pat. No. D729,485 for a “Dual Recycler” (right) with red arrows and blue circles indicating disputed lines in Simplehuman LLC v. iTouchless Housewares and Prods., Inc., 506 F. Supp. 3d 830 (N.D. Cal. 2020)

The court reasoned that because the purported drafting technique in the examples above made it impossible to distinguish contour changes from ornamental lines, and because such ambiguous usage raises indefiniteness concerns that should be discouraged, a “plain meaning” interpretation was adopted, finding that the disputed lines are lines (that is, ornamental features in the form of seams, paint, or something else that appear as actual lines on the articles). The patentee’s arguments that the disputed lines were shading or contour lines merely meant to demonstrate the general shape of the trash can/recycling bin were rejected.

The case later settled, and was dismissed without a final ruling on infringement. But the patentee would undoubtedly have lost under the court’s construction that the disputed engineering-style lines meant visible ornamental lines — neither the patentee’s own products nor the accused products had any features that resembled visible lines in the relevant locations.

The Title is Limiting

U.S. design patents are directed to ornamental features of useful articles. Significantly, they cover only particular articles that embody the claimed design, and not simply a “view” or “look” in the abstract (as is the case for industrial designs in some other jurisdictions). The words of the claim — which always says “as shown and described” — will limit the scope of the exclusive patent legal rights. Courts have said that the title of a design patent is limiting, where it names a particular type of article. And that is the case even if the drawings of a design patent do not illustrate any particular article. So the title and other words in a design patent application should be chosen carefully.

In the example reproduced above, a figure from a design patent shows a “Y”-shaped, rattan wickerwork-style pattern formed by a web of material. None of the figures in the patent illustrated the design being applied to a particular article, only the pattern formed by a portion of material shown in isolation. But the title of the patent is “Pattern for a Chair”. A court ruled that the patent’s claim was limited to a pattern for a chair, as specified in the title, and a lawsuit against a seller of a basket (not a chair) with a similar pattern making up the basket/bin walls was dismissed for failure to state a plausible claim of design patent infringement.

Sole figure in App. Ser. No. No. 29/491,550 (now U.S. Pat. No. D979,060) for a “Lip Implant”
image of prior art "stump" tool
Image of prior art “stump” art tool considered in In re SurgiSil, L.L.P., 14 F.4th 1380 (Fed. Cir. 2021)

Limits on claim scope by the title or other text might help distinguish prior art. In the example images above, a design patent claim for the “ornamental design for a lip implant” was limited to lip implants. A court said that a prior art tool made of tightly spiral-wound paper called a “stump”, used by artists for smoothing and blending large areas of pastel, charcoal, or pencil, was directed to a different article than the claimed lip implant. Therefore, the prior art “stump” did not affect the novelty of the claimed design even though their shapes were essentially the same.

The title of a design application can also limit the prior art available as “comparison” art in a three-way comparison of the claimed design, an accused product, and the closest prior art for an infringement analysis. Such a comparison can potentially highlight differences (or similarities) in the overall appearance that might not otherwise be apparent to an ordinary observer. To qualify as comparison prior art, a prior-art design must be applied to the article of manufacture identified in the claim.

Partial Claims Are Permitted

It is possible to depict an article while using a partial claim that addresses the design of only a portion of that article. Structure that is not part of the claimed design, but is considered necessary to show the environment in which the design is associated, may be represented in the drawing by broken lines. This includes any portion of an article in which the design is embodied, or applied to, that is not considered part of the claimed design. For instance, when the design is for surface ornamentation, the shape of article to which the design is applied can be shown in broken lines.

example design patent application drawings showing broken lines to indicate a partial claim to only surface ornamentation on a jewelry cabinet
Example of partial claim to only a surface pattern on a jewelry cabinet article, for USPTO design patent application guide

Moreover, unclaimed things may be shown in broken lines for the purpose of illustrating the environment in which the article embodying the design is used. For instance, a claimed design might be for the hood of a truck, only, with the rest of the truck shown in broken lines as unclaimed environment.

Unclaimed subject matter must be described as forming no part of the claimed design or of a specified embodiment thereof. A boundary line may be shown in broken lines if it is not intended to form part of the claimed design. Applicant may choose to define the bounds of a claimed design with broken lines when the boundary does not exist in reality in the article embodying the design. It would be understood that the claimed design extends to the boundary but does not include the boundary.Unclaimed subject matter must be described as forming no part of the claimed design or of a specified embodiment thereof. In this situation, broken (dashed) lines are used to define the boundary of a design patent application claim. This practice in the U.S. departs from that of some other countries where partial claims are not permitted.

Additionally, structure that is not part of the claimed design, but is considered necessary to show the environment in which the design is associated, may be represented in the drawing by broken lines. This includes any portion of an article in which the design is embodied, or applied to, that is not considered part of the claimed design.

USPTO Will Often Not Permit Changes in Claim Scope by Amendment

One of the most controversial aspects of U.S. design practice is that changes in claim scope are usually not permitted. While partial claims are permitted in design applications, and while claims in utility patent applications are routinely permitted (even to remove limitations), since 2013 the USPTO does not ordinarily permit lines to be changed from solid to broken (dashed) to broaden the claim, or the reverse to narrow the claim. Instead, applicants are typically forced to file a separate application that changes the scope of the claim. While examiners have some discretion to permit drawing changes, such as to fix discrepancies by changing lines to broken ones, and the text of disclaimers or statements in an appendix might have some impact, those things are not certain to be effective under current law and practice.

This practice of precluding changes in design application claim scope extends an already controversial position taken by a U.S. appeals court that reads a so-called “written description” possession requirement into the U.S. patent statutes (relating to enablement) against their plain language and grammar. Note that there is also a clear incentive for the USPTO to require new filings instead of amendments in order to generate more filing fees.

Multiple Embodiments are Sometimes Permitted

It is possible to include multiple embodiments in a single U.S. design application. However, restriction practice still applies and may require dividing different embodiments/designs into separate applications. Because design applications can have only a single claim, multiple embodiments must be patentably indistinct to remain in a single case.

On the one hand, because design patents have a 15-year term from grant, later-filed and later-granted divisional applications will expire later. This might be desirable for some patentees. On the other hand, a restriction determination also has an impact on the scope of exclusive rights. For instance, if the applicant elects one embodiment but declines to pursue an unelected embodiment in a divisional application, the unelected/abandoned embodiment will effectively be surrendered and dedicated to the public. These considerations emphasize the need to think through the implications and potentially commit to filing multiple applications when multiple distinct design embodiments are involved.

Drawings Must be Definite and Enabling

Drawings in a design patent application must be consistent with each other. Discrepancies between different views can create indefiniteness and/or lack of enablement issues. For instance, if certain features are shown in one view but omitted in another, this may make it unclear what design is really being claimed. The use of inconsistent drafting techniques in different drawings can also lead to similar concerns. For instance, discrepancies in the use of shading lines, stippling, and/or broken lines can detract from required clarity. Particularly for highly complex illustrations, it is important to carefully review the drawings to ensure that they are consistent.

A frequent issue is when there are holes, cavities, protrusions, or the like and their depth or height is potentially uncertain in plan or elevation views. Sometimes examiners may require cross-sectional views to show the depth of such features. But clarifying sectional views cannot always be added after initial filing without impermissibly adding new matter–instead a new continuation-in-part application might be necessary.

Mixing Photographs and Line Drawings is Not Permitted

Black and white line drawings are preferred and ordinarily required in U.S. design applications. However, photographs can sometimes be used, particularly where there is surface ornamentation that is not reproducible in line drawings. But it is not permitted to have both photographs and line drawings combined in a single design patent. It is possible to include a mix of photographs and line drawings in a new U.S. design application, which might have significance for priority claims or divisional filings, but the drawings must be amended and limited to one or the other type before grant. If photographs are included as informal drawings in a new application, then a disclaimer included in the specification or on the photographs themselves should be used to disclaim any color, surface ornamentation, logos, written matter, etc. that forms no part of the claimed design.

Color Can be Claimed

Use of color presents many opportunities for procedural problems and well as unintended impacts on the scope of claimed design patent rights. Color can be claimed in a design patent application. However, the use of color drawings (including color photographs) requires filing a petition and paying a petition fee to have color drawings accepted. Also, there is a requirement that the specification include the following statement:

“The patent or application file contains at least one drawing executed in color. Copies of this patent or patent application publication with color drawing(s) will be provided by the Office upon request and payment of the necessary fee.”

Instead of using color drawings, an alternative is to use black & white line drawings lined for color in accordance with the drawing symbols in MPEP § 608.02 (and reproduced in the USPTO’s design patent application guide). Essentially there are particular line patterns usable to represent specific colors. If this is done, the application must state “The drawing is lined for color.” The specific colors lined in the drawing(s) may also be identified in the specification for clarity, as a kind of legend that explains the lining patterns from MPEP § 608.02.

USPTO drawing symbols for draftsmen
USPTO design patent application guide “Symbols for Draftsmen”

Also, if color photographs are initially submitted as informal drawings (to later be replaced with formal drawings) and the applicant does not consider the color to be part of the claimed design, a disclaimer should be added to the specification as follows: “The color shown on the claimed design forms no part thereof.” The USPTO will consider color an integral part of the disclosed and claimed design in the absence of a disclaimer filed with the original application.

Appendices Are Permitted

Although not specifically discussed in MPEP Chapter 1550, the USPTO’s design patent application guide, or reported court cases, the USPTO currently permits design applications to include an appendix. The appendix is never published in granted design patents. An appendix can include text statements, such as a purported reservation of the right to change solid lines to broken lines or vice-versa, additional views or embodiments, which could be in the form of line drawings, photographs, or both. The main purpose of an appendix is to potentially provide support for a greater range of amendments and/or continuing applications after initial filing.

Applicants will sometimes not include an appendix because they are unaware that it is possible to do so. After all, the USPTO does not expressly discuss them in any of its regulations or procedural guidelines. Courts have not definitively ruled on the permissible use of design application appendices, however. Yet design examiners generally allow applicants to include and rely on them and generally do not object to their use.

Functional Aspects Are Not Protected

Sometimes design patent applicants wrongly believe that a design patent will cover functional aspects or a general idea. They do not. The type of subject matter that can be claimed in design patents is different from utility patents.

Design patent protection is limited to protection of ornamental aspects of a useful article. Purely functional aspects or a broader general design concept are not protected. Where this becomes less clear is where design features are only partly functional, and they contribute at least some minimal ornamentation to the overall design. In those situations, the functional aspects limit the scope of protection in the overall design without completely precluding protection of the minimally ornamental aspects. Also, anything dictated by function, no matter how aesthetically pleasing, cannot be protected by a design patent.

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Austen Zuege is an attorney at law and registered U.S. patent attorney in Minneapolis whose practice encompasses patents, trademarks, copyrights, domain name cybersquatting, IP agreements and licensing, freedom-to-operate studies, client counseling, and IP litigation. If you have patent, trademark, or other IP issues, he can help.

Copyrights Patents Q&A Trade Secrets Trademarks

How Can I Protect the Design of My Business’ Products?

Intellectual property (IP) rights might allow a business to obtain exclusive rights in some or all aspects of a product. Such IP rights can potentially include patents, trademarks (i.e., trade dress), copyrights, and trade secrets. But the types of IP that might apply will vary depending on the context of the product involved, and may require affirmative action to secure and maintain IP rights.

Consider patentability before any public disclosure or commercialization of a product in order to avoid potential loss of patent rights.  Although other types of IP protection might be available, exclusivity in the design of a new useful product is first and foremost a question of potential patent protection.

Patent Protection

Patents can provide exclusive rights for a limited time in exchange for disclosure of an invention. An inventive product—and/or a process or method associated with making or using it—can be protected with a utility patent.  However, a patent application must be filed within one year of public disclosure or commercialization (or, in other countries, before any public disclosure).  The invention must also satisfy three criteria for patentability: utility, novelty, and non-obviousness. The latter two criteria depend on the scope and content of the prior art.  A patentable invention cannot already be known and must represent a non-trivial advance over what was already known.  These assessments are made in an absolute sense. Prior art is not limited to commercially available products. And it does not matter whether or not the inventor actually knew about the relevant prior art. 

The ornamental appearance of a useful article can be protected with a design patent if the ornamental design is novel and non-obvious. Design patents can cover surface ornamentations for an article of manufacture, the ornamental shape or configuration of an article of manufacture itself, and combinations of those categories. Abstract designs (e.g., a picture standing alone) are not patentable.

Trade Dress / Trademark Protection

Trade dress (a form of trademark protection) may also protect the distinctive, nonfunctional appearance of a product or its packaging.  However, trade dress protection only arises in aspects of product configuration that serve as a trademark to allow consumers to identify the source of the product. Trade dress never protects functional aspects of product configuration or packaging. In other words, it is limited to aspects that relate to the manufacturer or seller’s reputation and not to the usefulness of the thing itself.

In the U.S., trade dress protection requires achieving acquired distinctiveness once secondary meaning has developed in the minds of consumers based upon substantially continuous exclusive use for a sufficient period of time (generally a minimum of five years).  Trade dress will not provide exclusive rights in product configuration at the time of a new product’s launch, though it might for packaging. 

Copyright Protection

Copyright might apply to certain aspects of products, such as product labels or decorative graphics applied onto a product.  But copyright will not protect useful or functional parts, only those creative aspects that are conceptually separable and capable of existing apart from the useful or functional parts. For example, a lamp that incorporates a sculpture could have copyright protection in the sculptural elements but purely functional electrical components that allow the lamp to illuminate would not have copyright protection. The text of software code can be copyrightable but not the functionality enabled by software (which might be patentable instead).

Trade Secret Protection

Trade secret protection will not apply to publicly visible or readily ascertainable aspects of a product. But things like the “secret formula”, manufacturing methods, or aspects of embedded software might be protectable as trade secrets if they are not generally known and not readily ascertainable and you take reasonable measures to keep such things secret.

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Austen Zuege is an attorney at law and registered U.S. patent attorney in Minneapolis whose practice encompasses patents, trademarks, copyrights, domain name cybersquatting, IP agreements and licensing, freedom-to-operate studies, client counseling, and IP litigation. If you have patent, trademark, or other IP issues, he can help.

Patents Q&A

Can You Patent a Software App?

Patents are available for inventions.  Software per se is not patent eligible—source code text is copyrightable instead.  But a system, apparatus, or device configured to execute particular software-driven functions may be patent eligible and a method (or process) that is computer-implemented via software may also be patent eligible.  Ornamental aspects of software-driven graphical user interfaces (GUIs) are also eligible for design patent protection.  So, a software “app” (application) as a discrete whole is usually not patentable as such but a patentable invention might include or implicate some software-based aspect. 

The U.S. Supreme Court has said that “abstract ideas” are not patent eligible, which narrows the types of software-based inventions that are patentable.  A software-based invention that consists only of well-known concepts, mathematical calculations, data processing/manipulation/selection/presentation, what could otherwise be performed as purely mental steps, or the like plus merely generic computer hardware is generally not patent eligible.  Software that provides no more than an allegedly improved user experience is also generally not patent eligible.

Patent eligibility hinges on the particular “claims” in a patent application or granted patent, which establish the scope of a patentee’s exclusive rights.  More narrowly-drawn claims that focus on a particular inventive feature (e.g., a detailed computer-implemented algorithm) that solves a specific technological problem (e.g., improves computer hardware performance as a tool or transforms physical outputs in a new or improved way) are more likely to be patent eligible than broad, highly abstract claims (e.g., attempting to patent any insertion of an ad before an online streaming video plays).  In this sense, software patent eligibility is highly dependent on how the claims are written, an area where patent applicants have wide latitude.  Attempts to obtain a broad “preemptive” (or we might say greedy) patent monopoly that exceeds the quid pro quo of the inventor’s contribution to the useful arts raise the most concerns. 

Additionally, a software-based invention must be both novel and non-obvious over the prior art to be patentable, just as with any type of invention.  In this respect, all invention, software-based ones included, must represent a non-trivial advance over what is already known in order to be patentable.  Whether the inventor actually knew about the closest prior art or not is irrelevant—any and all prior art represents a potential barrier to patenting a new invention.

In summary, while you generally cannot patent a software app as a stand-alone product, aspects of software-enabled products or processes may be patent eligible. The real answer to this question is that it often depends on the what invention is, what was known before, and how you try to claim a software-based invention in a patent application.

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Austen Zuege is an attorney at law and registered U.S. patent attorney in Minneapolis whose practice encompasses patents, trademarks, copyrights, domain name cybersquatting, IP agreements and licensing, freedom-to-operate studies, client counseling, and IP litigation. If you have patent, trademark, or other IP issues, he can help.

Patents Q&A

What Types of Patents and Patent Applications are Available?

There are a number of different types of patents and patent applications. The available types of patents and patent applications also vary by country. Before turning to those specifics, an important initial distinction to note is between a patent application and a granted patent.

Patent Applications Versus Granted Patents

A patent and a patent application are not the same thing. This is a common source of confusion for those unfamiliar with patent law.

Patent Applications

A patent application is essentially a request by an inventor/applicant to obtain a patent. It is a custom-prepared document rather than a template form that is filled-in. Simply filing a patent application does not by itself entitle the applicant or inventor to enforceable legal rights. More is required to secure enforceable exclusive rights in an invention. Filing a patent application is just the first step in that process. Importantly, applications generally have to undergo an official examination to assess patentability. The applied-for invention may or may not be patentable.

Pending patent applications are normally (but not always) published after approximately 18 months. This means that there are publicly-available “patent application publications” or “published patent applications”. But these still only pertain to a (pending) patent application as opposed to a (granted) patent. A patent application publication, alone, is not enforceable.

There is really nothing final about a patent application when it comes to rights in an invention. Whether published or unpublished, the existence of a patent application really only means that someone currently is or was in the past pursuing patent protection. A good analogy is somebody filing a complaint to a commence a lawsuit: they hope to win, eventually, but merely initiating the lawsuit is not the same as a final judgement on the merits. There can be changes to a patent application while it is pending. So the published version of a given application may not fully reflect its current contents. And patent applications can be abandoned entirely.

Granted Patents

A patent is granted (or issued) by a government as a “public franchise” and gives the owner(s) exclusive rights to an invention. The scope of the enforceable legal rights are defined by the claim(s) of the patent. A patent is also enforceable only in a given jurisdiction. There is no such thing as an international patent enforceable throughout the world. So obtaining exclusive legal rights in multiple countries usually requires obtaining patents in each of those individual countries—though a few regionally-enforceable patents exist outside the USA. In the U.S., a granted patent is presumed valid because it has undergone pre-grant examination to assess patentability. Though even granted patents can still be challenged.

Every patent starts out as a patent application. And there may be multiple patent applications related to a given patent. But, on the other hand, any given patent application might or might not turn into a granted patent. A patent office may reject the patent application because the claimed invention is unpatentable, for instance. Or an applicant may simply abandon an application before a patent is granted for a variety of reasons.

Patent Families

Patents and patent applications that are formally related to each other are often referred to as a patent “family”. This includes reference to “parent” and “child” patents and applications.

Types of Patents

There are three types of patents available in the United States for different types of inventions:

  • Utility
  • Design
  • Plant

Utility patents are directed to useful inventions. If someone refers merely to a “patent”, chances are they mean a utility patent. Most U.S. patents are utility patents. In other countries these may have a slightly different name, like invention patents in the People’s Republic of China.

Design patents are directed to inventive ornamental designs of useful articles. They do not cover functional features or designs in the abstract—unconnected to an article of manufacture. In some other countries, designs are not covered under patent laws but instead as either “industrial designs” that are a unique type of protection or something closer to trademark (trade dress) protection.

Plant patents cover inventive asexually reproduced plants. Some inventions related to plants can be protected by utility patents, which is to say that a plant patent is not the only possible type of patent protection available for plant-related inventions.

The types of available patents are not the same around the world. In some countries, utility models or petty patents are available. But those types of patents do not exist in the USA.

Types of Patent Applications

There are a number of different types of patent applications in the USA:

  • Provisional
  • Nonprovisional
    • Continuing Applications:
      • Divisional
      • Continuation
      • Continuation-in-Part (CIP)
  • PCT International Application (and associated National Phase Entry)
  • Hague International Design Application
  • Reissue

Provisional applications are not examined but can be relied upon by a later-filed non-provisional application claiming “priority” to the provisional. They serve as a kind of temporary placeholder to preserve rights to file a nonprovisional application within a year. Provisional applications are available only for utility and plant inventions. They are not available for design inventions. The U.S. and a few other countries permit provisional applications but most countries do not.

A nonprovisional application is essentially just a regular patent application. It can be an application for a utility, design, or plant invention. Nonprovisional applications in the U.S. undergo substantive examination and can potentially result in a granted patent.

Continuing applications are special types of nonprovisional applications that claim priority to an earlier, co-pending domestic U.S. nonprovisional application or PCT international application designating the U.S. But an application with a priority claim to a prior foreign application or U.S. provisional application is not considered a continuing application. What is called a “divisional” application in many other countries might be called either a “continuation” or “divisional” application in the U.S.

The PCT system, which is administered by a United Nations agency (WIPO), provides a sort of application clearinghouse to facilitate the pursuit of patent protection in various participating countries. But the PCT system still requires action in individual countries or regions. At the start, a (single) PCT international application that designates selected participating countries (usually all participating countries) is filed in a “receiving office”. The international application can then later enter the national phase (or regional phase) in one or more designated countries or regions. A PCT national (or regional) phase entry is actually not separate from the PCT international application but merely represents a different (national/regional) phase in the life of the same international application.

Hague international design applications are roughly the equivalent of a PCT application but for design inventions.

Reissue applications are applications to correct an error in an issued patent. In other words, reissues only arise after a patent has already been granted. Broadening reissues, which enlarge the scope of the claim(s), must be filed within two years of grant of the underlying patent. Other (non-broadening) reissue applications are not subject to the two-year filing deadline. Grant of a reissue results in surrender of the original patent.

Have an invention you would like to patent? Have a brand you would like to register as a trademark? Concerned about infringing someone else’s intellectual property? Is someone else infringing your IP? Need representation in an IP dispute? Austen is a patent attorney / trademark attorney who can help. These and other IP issues are his area of expertise. Contact Austen today to discuss.

Patents Q&A

What Is a Design Patent?

There are three types of patents available in the United States: utility patents, plant patents, and design patents. Each type of patent addresses different types of inventions. What does a design patent cover?

A design patent covers a new, original ornamental design for an article of manufacture. (35 U.S.C. § 171). Put another way, a design patent protects the overall visual appearance of a useful article. This can involve surface ornamentation applied to or embedded in the article, the shape of the article itself, or combinations of such things.

It is important to note what design patents do not cover. They do not protect designs in the abstract that are unconnected to an article of manufacture. An original artistic painting is copyrightable but cannot be the subject of a design patent because there is no article of manufacture present. Also, design patents do not cover useful features as such, only ornamentation. Useful aspects are properly addressed only in utility patents. Anything with an appearance entirely dictated by function lacks ornamentality. However, a design patent must relate to a useful article and aspects of the claimed design can be useful, so long as there is visual ornamentation that—as a whole—goes beyond the purely functional aspects.

In many other countries, designs are not covered by patent law but rather “industrial designs” are registered as a different type of intellectual property (IP). Other countries sometimes administer industrial design registrations in a manner adjacent to or related to trademarks.

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Austen Zuege is an attorney at law and registered U.S. patent attorney in Minneapolis whose practice encompasses patents, trademarks, copyrights, domain name cybersquatting, IP agreements and licensing, freedom-to-operate studies, client counseling, and IP litigation. If you have patent, trademark, or other IP issues, he can help.


Conceptualizing Negative Limitations in Design Patents

Is it possible for a U.S. design patent claim to include a negative limitation? It does not appear that courts have explicitly addressed this question. That is partly due to emphasis on design patent claims and infringement analyses revolving around the design as a whole, which can lead to rather conclusory decisions. But the question posed here is whether a claimed ornamental design as a whole can contain within it one or more “negative limitations” that effectively indicate the absence of some ornamental aspect, as opposed to indicating the positive (or affirmative) presence of an ornamental aspect. Certain past cases have touched on similar issues without specific reference to “negative limitations” in the sense that term is used with regard to utility patent claims.

Consider a design patent claim that shows as part of the overall ornamental design a flat surface, that is, a solid planar surface that is plain and uninterrupted. Does such a depiction include a negative limitation of sorts that excludes the presence of ornamentation on the surface? That is, does it give rise to a potentially significant overall difference when comparing a perforated surface or a surface that has substantial non-planar texturizing surface ornamentation? The same questions might arise, for instance, when a claimed design depicts only a single element (such as a single rounded corner, single support bar, single hole, etc.) but the accused product includes more than one of those elements.

In general, design patent infringement analysis involves two steps: (1) claim construction and (2) comparison of the properly construed claim to the accused product. Elmer v. ICC Fabricating, Inc., 67 F.3d 1571, 1577 (Fed. Cir. 1995). Theoretically, at least, questions about “negative limitations” in design patents could potentially arise in either of those two steps.

While, certainly, a jury can always reach an ultimate infringing/non-infringing conclusion, in the binary sense, based on the particular and specific facts at hand in any given case. But the topics at hand here are how courts should treat the legal issues surrounding how a finder of fact might be presented with design patent infringement questions where negative limitation issues are present, and also how courts making dismissal (Rule 12(b)(6)), summary judgment, judgment on the pleadings, judgment as a matter of law (JMOL), or appeal decisions can explain their reasoning under the ordinary observer test when negative limitations may be present.

Negative Limitations in Design Claim Construction

Design patent infringement analysis begins with claim construction. Although claim construction is also the first step in utility patent infringement analysis, design patent claim construction differs from that for utility patents in some important ways.

A patentable design “gives a peculiar or distinctive appearance to the manufacture, or article to which it may be applied, or to which it gives form.” Gorham Co. v. White, 81 U.S. (14 Wall.) 511, 525 (1871); see also Samsung Elecs. Co., Ltd. v. Apple Inc., 580 U.S. ___, 137 S. Ct. 429, 432-33 (2016).  This means design patent claim construction must be adapted to the pictorial setting. Crocs, Inc. v. Int’l Trade Comm’n, 598 F.3d 1294, 1302 (Fed. Cir. 2010). In that sense, the Federal Circuit has said that “[d]epictions of the claimed design in words can easily distract from the proper infringement analysis of the ornamental patterns and drawings.” Id.; see also Dobson v. Dornan, 118 U.S. 10, 14 (1886) (a claimed design “is better represented by the photographic illustration than it could be by any description, and a description would probably not be intelligible without the illustration.”). 

The Federal Circuit has cautioned that detailed verbal claim constructions increase “the risk of placing undue emphasis on particular features of the design and the risk that a finder of fact will focus on each individual described feature in the verbal description rather than on the design as a whole.”  Egyptian Goddess, Inc. v. Swisa, Inc., 543 F.3d 665, 680 (Fed. Cir. 2008) (en banc).  For such reasons, the level of detail to be used in describing the claimed design is a matter within a court’s discretion, and a court is not obligated to issue a detailed verbal description of the design if it would not be helpful. Id. at 679-80.  Yet a court may use claim construction to help guide the fact finder through issues that bear on claim scope. Id. at 680. 

Although not always at issue in every case, design patent claim construction can address prosecution history estoppel and prosecution history disclaimer.  See Egyptian Goddess, 543 F.3d at 680.  In general, the doctrine of prosecution history estoppel prevents a patentee from “recaptur[ing] in an infringement action the very subject matter surrendered as a condition of receiving the patent.” Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co., Ltd., 535 U.S. 722, 734 (2002).  It requires that “the claims of a patent be interpreted in light of the proceedings in the [US]PTO during the application process.” Id. at 733. The Federal Circuit has specifically held that prosecution history estoppel applies to design patents too.  Pac. Coast Marine Windshields Ltd. v. Malibu Boats, LLC, 739 F.3d 694, 702 (Fed. Cir. 2014). 

However, for design patents, unlike with utility patents, “the concepts of literal infringement and equivalents infringement are intertwined.”  Id. at 700-01.  Because it is the drawings of the design patent that provide the description of the invention, courts “look at the requisite drawings in design patents to determine whether a surrender has occurred.” Id. at 702.  Estoppel arises when a narrowing amendment is made to satisfy any requirement to secure the grant of the patent, including amendments to avoid prior art or resulting from a restriction requirement.  Id. at 703-04; see also Advantek Marketing Inc. v. Shanghai Walk-Long Tools Co., 898 F.3d 1210, 1216-17 (Fed. Cir. 2018).

In the Pacific Coast Marine Windshields case, a design application (for U.S. Des. Pat. No. D555,070) originally included drawings depicting—and claiming—multiple embodiments of a boat windshield. As reproduced below, the various originally-claimed embodiments showed the claimed windshield design with different vent hole configurations and also showed claimed designs that included and excluded a hatch on the front of the windshield. The examiner issued a five-way restriction requirement, identifying five distinct groups of designs as windshields with:

  1. four circular holes and a hatch (FIG. 1);
  2. four circular or square holes and no hatch (FIGS. 7 and 12);
  3. no holes and a hatch (FIG. 8);
  4. no holes and no hatch (FIG. 9); and
  5. two oval or rectangular holes and a hatch (FIGS. 10 and 11).
Grid of selected original figures from the application for Des. Pat. No. D555,070

In that sense, the examiner indicated that many of the different embodiments (but not all of them) represented different design inventions. In response, the patentee removed alternate embodiments, thus deleting those alternate embodiments from the scope of the claim. That prosecution history had significant implications to the scope of the claim in the granted design patent before the court (D555,070). Incidentally, the patentee chose to file only one subsequent divisional application to the “no holes and a hatch” embodiment (that became U.S. Des. Pat. No. D569,782), apparently without pursuing any other of the original alternate embodiments—though a continuation application (that became U.S. Des. Pat. No. D593,024) based off the divisional was also later filed for a partial design to only the vertical corner posts with no vent holes (with the windscreen portions unclaimed, thus potentially avoiding hatch vs. no hatch questions).

Noting that treatises and prior district court decisions had said similar things in the past, the Federal Circuit ruled that surrender of claims to the alternate designs was for reasons of patentability that caused prosecution history estoppel to attach. Pac. Coast Marine Windshields, 739 F.3d at 702-04. However, because the accused windshield product’s design had three vent holes (see above) but the patented design had four vent holes (see FIG. 1 above) and the surrendered embodiments/designs had only two vent holes (see original FIGS. 10 and 11 above), summary judgment of non-infringement was reversed and the case was remanded to the district court for further proceedings. Id. at 704-05. In other words, without reaching a definitive infringement/non-infringement decision, the patentee was barred from arguing that the design patent’s claim covered a two-hole design (or any other surrendered embodiments) but was still able to argue that a three-hole design might be covered because there was no surrendered three-hole embodiment in the original drawings. (The Federal Circuit decision did not address potential differences in the horizontal/angled frame or trim aspects of the accused design as part of the overall appearance analysis). After remand, and denial of subsequent summary judgment cross motions (which included inventorship disputes, and non-patent issues), the parties eventually settled.

Generally similar negative limitation issues have arisen in utility patent cases. For example, the Spine Solutions case involved questions of claim construction and prosecution history estoppel for a utility patent. Claim 1 of the patent in question recited “a single anchor on each of the upper surface of the upper part and the lower surface of the lower part . . . .” The relevant claim construction implicitly regarded the “single anchor” recitation as including a negative limitation, that is, requiring one anchor having the recited characteristics but excluding the presence of more than one anchor. There was no infringement by the accused device, which had two anchors rather than a “single” anchor as claimed. The Federal Circuit reasoned as follows:

“We agree with [the accused infringer] Medtronic that the court erred in determining that [the accused] O-Maverick [device] literally infringes claims 1 and 2. The [district] court construed ‘single anchor’ to mean, in relevant part, that ‘[t]he upper and lower surfaces of the implant each have one anchor having the characteristics recited in the last paragraph of [claim 1].’ Claim Construction Order, 2008 WL 4831770, at *14, 2008 U.S. Dist. LEXIS 116648, at *43 (emphasis added). A simple observation of [the accused] O-Maverick [device] confirms that the implant has two anchors on each of the upper and lower pieces, not one. The anchors are separated by a one-millimeter gap that extends all the way to the base of the implant; at no point are the two anchors joined or connected in any way. O-Maverick clearly has two anchors on each piece, not a ‘single anchor’ as recited by claims 1 and 2. Therefore, we hold as a matter of law that [the accused] O-Maverick [device] does not literally infringe claims 1 and 2.

“During prosecution, applicants expressly distinguished the claimed invention over the ‘477 patent by asserting that ‘a reference disclosing two anchors does not disclose a device affirmatively claiming a single anchor… reciting a negative limitation in the form of a single element is not disclosed by prior art which teaches more than one element.’ J.A. 17524. This is a clear disclaimer of claim scope, and prosecution history estoppel therefore bars [the patentee] SSI from arguing that a two-anchor device is equivalent to the claimed implant. Because we hold that [the accused] O-Maverick [device] is a two-anchor device, SSI cannot argue that O-Maverick infringes claims 1 and 2 under the doctrine of equivalents.”

Spine Solutions, Inc. v. Medtronic Sofamor Danek USA, Inc., 620 F.3d 1305, 1316-17 (Fed. Cir. 2010).

What all these cases emphasize is that negative limitations can be at issue for design patent claim constructions, just as in utility patent cases. Prosecution disclaimer or prosecution estoppel issues resulting from arguments or amendments to a design application are especially relevant here. The Pacific Coast Marine Windshields case illustrates how those issues should be assessed as part of a design claim construction, if and when they arise. Other cases also indicated how this can be significant with respect to words in the design patent claim — such as words in the title that restrict the scope of the claim to a particular article of manufacture. Curver Luxembourg, SARL v. Home Expressions Inc., 938 F.3d 1334, 1340 (Fed. Cir. 2019); In re SurgiSil, L.L.P., No. 2020-1940 (Fed. Cir. Oct. 4, 2021). It is possible a design patent might include words like “individual” in the title that could include a negative limitation.

What is less certain for design patent claim construction is what role, if any, negative limitations have when the feature in question is something that appears in a drawing but there was no prosecution history disclaimer or estoppel. Because detailed design claim constructions that translate visual depictions into words are disfavored, it would not be appropriate in most situations to single out a particular visual element and explicitly construe it as containing a negative limitation (in the absence of a disclaimer or estoppel). That would depart from the context of the ordinary observer analysis and the requisite visual analysis of the overall appearance of the ornamental design.

Yet there may be instances where a negative limitation appears in relation to functional features, for example. The Federal Circuit has held that a claim construction may help the fact finder “distinguish[] between those features of the claimed design that are ornamental and those that are purely functional.” Egyptian Goddess, 543 F.3d at 680 (citing OddzOn Prods., 122 F.3d at 1405).  A design may contain both functional and ornamental elements, even though the scope of a design patent claim “must be limited to the ornamental aspects of the design.” Ethicon Endo-Surgery, Inc. v. Covidien, Inc., 796 F.3d 1312, 1333 (Fed. Cir. 2015). “Where a design contains both functional and non-functional elements, the scope of the claim must be construed in order to identify the non-functional aspects of the design as shown in the patent.” OddzOn Prods., 122 F.3d at 1405; accord Ethicon Endo-Surgery, Inc., 796 F.3d at 1333.  This ensures that the claim is limited to the ornamental aspects of the design, and does not extend to “the broader general design concept.” OddzOn Prods., Inc., 122 F.3d at 1405; see also Read Corp. v. Portec, Inc., 970 F.2d 816, 825 (Fed. Cir. 1992) (“[w]here . . . a design is composed of functional as well as ornamental features, to prove infringement a patent owner must establish that an ordinary person would be deceived by reason of the common features in the claimed and accused designs which are ornamental.”).  But a construction of design features that are only partly functional, with some at least minimal ornamentation, must not entirely eliminate whole aspects from the scope of the claim, even as the functional elements limit and narrow the claim scope.  See Sport Dimension, Inc. v. Coleman Co., Inc., 820 F.3d 1316, 1322-23 (Fed. Cir. 2016); Apple Inc. v. Samsung Elecs. Co., Ltd., 786 F.3d 983, 998-99 (Fed. Cir. 2015).

Negative Limitations in Comparisons Between Claimed Design and Accused Product

Following claim construction, if any, the design patent’s claim as construed is compared to the allegedly infringing products. Elmer, 67 F.3d at 1577.  When considering infringement of a design patent, the “ordinary observer” test is the sole test for determining if infringement has occurred. Egyptian Goddess, 543 F.3d at 678 (rejecting the use of a separate “point of novelty” test); Crocs, 598 F.3d at 1303.  Under the ordinary observer test, infringement occurs:

“if, in the eye of an ordinary observer, giving such attention as a purchaser usually gives, two designs are substantially the same, if the resemblance is such as to deceive such an observer, inducing him to purchase one supposing it to be the other, the first one patented is infringed by the other.”

Gorham, 81 U.S. at 528; Egyptian Goddess, 543 F.3d at 670-71.

This test has been codified in the patent laws, which provide as follows:

“Whoever during the term of a patent for a design, without license of the owner, (1) applies the patented design, or any colorable imitation thereof, to any article of manufacture for the purpose of sale, or (2) sells or exposes for sale any article of manufacture to which such design or colorable imitation has been applied shall be liable to the owner to the extent of his total profit, but not less than $250, recoverable in any United States district court having jurisdiction of the parties.”

35 U.S.C. § 289

Thus, as the ordinary observer test is sometimes described, infringement is not found unless the accused article embodies the patented design or any colorable imitation of it. Egyptian Goddess, 543 F.3d at 678 (citations omitted). Though recall that for design patents “the concepts of literal infringement and equivalents infringement are intertwined.”  Pac. Coast Marine Windshields, 739 F.3d at 700-01. 

Against that backdrop, the question of potential negative limitations can arise in the context of whether logos (or the like) present on the accused product can or should be considered when comparing it to the design patent claim to determine if there is infringement.

It is necessary to compare the claimed design (as construed) as a whole to accused product. Ethicon Endo‐Surgery, 796 F.3d at 1335; Crocs, 598 F.3d at 1302-06. This is to say that in the “ordinary observer” analysis, the patented design is viewed in its entirety, as it is claimed.  L.A. Gear, Inc. v. Thom McAn Shoe Co., 988 F.2d 1117, 1125 (Fed. Cir. 1993). “[A]ll of the ornamental features illustrated in the figures must be considered in evaluating design patent infringement.”  Contessa Food Prods., 282 F.3d at 1378.  “A patented design is defined by the drawings in the patent, not just by one feature of the claimed design.” KeyStone Retaining Wall Sys., 997 F.2d at 1450. This means the comparison of the claimed design (as construed) to the accused product must generally include all of the patent figures in comparison, and it cannot merely compare separate elements in isolation or involve serial element-by-element comparison.

Yet an infringement analysis that recites significant differences between the ornamental features of the claimed and accused designs is still acceptable if, in determining infringement, that analysis still mainly focuses on whether an ordinary observer would be deceived into thinking that the accused product’s design was the same as the patented design. Richardson v. Stanley Works, Inc., 597 F.3d 1288, 1295-96 (Fed. Cir. 2010). It is in that sense that negative limitations can be used to help articulate significant differences from the standpoint of an ordinary observer.

Along those lines, the Federal Circuit has held that the finder of fact can consider “an ornamental logo, its placement, and its appearance as one among other potential differences between a patented design and an accused one.” Columbia Sportswear N. Am., Inc. v. Seirus Innovative Accessories, Inc., 942 F.3d 1119, 1131 (Fed. Cir. 2019). In a subsequent August 2021 trial under that guidance, a jury found no infringement. Columbia Sportswear N. Am., Inc. v. Seirus Innovative Accessories, Inc., No. 3:17-cv-01781 (S.D. Cal. Aug. 6, 2021) (jury verdict of non-infringement). The parties subsequently cross appealed.

In Columbia, the patent owner sometimes made a comparison of only a selected portion of the claimed design to the accused product in briefing. This had the effect of broadening the asserted claim. For instance, in the first comparative example below for district court summary judgment briefing, note how the claimed design uses broken lines in FIG. 1 to show that a boundary exists but is unclaimed (see MPEP § 1503.02(III) (9th Ed., Rev. 10.2019, June 2020)). But the claimed design of FIG. 1 includes a generally sinusoidal wave pattern with four full crests and five full troughs that appear uninterrupted between the broken line boundaries; whereas in a comparison table used in briefing only part of the claim with merely three full (and uninterrupted) crests and troughs was reproduced as allegedly being the “Patented Design”. And in the second example below, from appellate briefing, note how FIG. 2 is used by the patentee for comparison despite the asserted design patent stating that “FIG. 2 is an enlarged elevational view thereof, taken from any area in the design” (that is, FIG. 2 merely shows an enlargement of a portion [with]in the claimed design but does not show the entire claimed design). If we analogize this to the utility patent context, it is like comparing a selected claim limitation to the accused product in isolation without addressing one or more additional limitations present in the claim. The significance of the accused product’s interruption (with repeating logos) in comparison to the claimed uninterrupted design was a key issue in the case including its appeals. So the question of what constitutes the full scope of the claimed design is foundational to what is or is not interrupted in the accused product.

The district court declined to construe the design patent claim with a detailed verbal description in its Markman order, or to provide any other construction or guidance about design patent conventions, but instead later provided jury instructions that stated:

“A design patent’s claim defines what is covered by the patent. The claim is typically represented by illustrations. It is permissible to illustrate more than one embodiment of a design in a single design patent application. Each design patent contains multiple drawings to illustrate the claimed design.

The scope of the claim encompasses the design’s visual appearance as a whole. It does not cover a general design concept and is not limited to isolated features of the drawings. An inventor’s subjective intent is not relevant to the scope of the claimed design”

Quote from Jury Instruction No. 9 (as filed Aug. 6, 2021)

That jury instruction (No. 9) was largely generic. It could have been issued in any design patent case without changing a word. Neither the jury instruction nor the Markman order specifically addressed the proper interpretation of the language describing FIG. 2 quoted above, which is part of the claim. Most significantly, the jury was not instructed to disregard the presence of logos on the accused product (as Columbia had sought). But, additionally, the jury was not instructed about whether the asserted design patent actually included multiple embodiments or whether certain drawings showed the same design or merely incomplete portions of it. That meant that, in the Columbia case, there was no express “negative limitation” claim construction. Instead, everything came down to the comparison of the overall appearances.

“To determine infringement of a design patent, you must compare the overall appearances of the accused design to the Design Patent. The accused design is Seirus’s HeatWave fabric. If you find by a preponderance of the evidence that the overall appearance of the accused design is substantially the same as the overall appearance of the Design Patent, you must find that the accused design infringed the Design Patent.

Two designs are substantially the same if, in the eye of an ordinary observer, giving such attention as a purchaser usually gives, the resemblance between the two designs is such as to deceive an ordinary observer, inducing him to purchase one supposing it to be the other. You do not need, however, to find that any purchasers were actually deceived or confused by the appearance of the accused products. You should consider any perceived similarities or differences between the patented and accused designs. Minor differences should not prevent a finding of infringement.”

Quote from Jury Instruction No. 10 (as filed Aug. 6, 2021)

The jury instruction (No. 10) regarding the comparison step did mention the accused product by name. But otherwise that instruction is also fairly generic. Jury instructions nos. 11-13 also pertained to design-patent-specific issues, including comments about the proper use of prior art in instruction no. 11.

The district court could have provided further claim construction guidance. But it chose not to. As already noted, the jury held that the patented design was not infringed. On the next appeal, there will surely be a dispute over the ultimate verdict of non-infringement of the design patent, but also perhaps about the mostly generic jury instructions related to design patent claim construction and infringement analysis and how those impact any “negative limitations” in the design patent claim. Though, interestingly, at the district court neither party really argued this point regarding the proposed final jury instructions for the August 2021 trial (most of the arguments over those instructions instead centered around what could be ignored, proper consideration of marketing materials evidence, how functionality should be referenced if at all, and the relevance and proper role of alleged prior art).


The appropriate way to address “negative limitations” in design patent claims is: first, to address in claim construction any prosecution history disclaimer or prosecution history estoppel issues that might give rise to recapture issues around such “negative limitations”, as well as any relevant interpretations of the text of the claim (including the title and description) that might do the same; and, second, to articulate the way design features affirmatively present in the accused design represent significant differences from such “negative limitations” in the claimed design in an analysis that still mainly focuses on whether an ordinary observer would be deceived into thinking that the accused product’s design was the same as the patented design overall.

The first aspect might not be relevant in all cases. Those questions will be highly dependent on the content of the asserted design patent claim and the prosecution history. But the second aspect could potentially apply whenever the asserted design patent appears to recite, in part, a “negative limitation”. This second part might impact jury instructions, as well as the way a case is argued to the finder of fact. It could also impact a pre-suit opinion of counsel analysis. Both factors might come up as part of dismissal, summary judgment, judgment on the pleadings, and/or JMOL motions, as well as in appeals.

January 2022
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Austen Zuege is an attorney at law and registered U.S. patent attorney in Minneapolis whose practice encompasses patents, trademarks, copyrights, domain name cybersquatting, IP agreements and licensing, freedom-to-operate studies, client counseling, and IP litigation. If you have patent, trademark, or other IP issues, he can help.


The Delicious Ironies of Food Product Configuration Protection

The Scope and Limits of Trade Dress and Patent Protection in Product Shapes: Food Product Case Studies

Intellectual property (IP) protection for product configurations of comestibles, confections, foodstuffs, and the like have been a matter of dispute in courts for well over a century. A variety of distinct IP rights may be invoked in this context, among them design patents and trade dress (either as a registered or unregistered trademark). Courts have grappled with the limits of such IP rights, seeking to prevent end-runs around the expiration of patent and copyright rights that the U.S. Constitution restricts to only limited times.[i] Such limits on IP rights embody long-standing Anglo-American legal principles in place since the Statute of Monopolies curbed the English Crown’s practice of granting “odious” monopolies over common commodities to raise funds or bestow favor.[ii] Cases up to the present highlight continued aggressive assertions of trade dress rights by foodstuff manufacturers—coupled with pushback by courts to deny trade dress rights in purely functional product configurations.

A number of important historical decisions observed the tendency for assertions of trade dress in (food) product configurations/shapes/forms/designs—these terms being used somewhat interchangeably—to inappropriately extend monopoly protections after a patent expired. Judge Learned Hand authored Shredded Wheat Co. v. Humphrey Cornell Co., which dealt with alleged trade dress infringement of the shape of shredded wheat biscuits after the expiration of a design patent to the same biscuit shape.[iii] He wrote that “the plaintiff’s formal dedication of the design [upon expiration of U.S. Des. Pat. No. 24,688] is conclusive reason against any injunction based upon the exclusive right to that form, however necessary the plaintiff may find it for its protection.”[iv]

Front page of U.S. Design Patent No. 24,688

Later, the Supreme Court weighed in on a dispute between Kellogg and Nabisco, finding the pillow shape of a shredded wheat biscuit to be functional because “the cost of the biscuit would be increased and its high quality lessened if some other form were substituted for the pillow-shape.”[v] The Court stated,

“The plaintiff has not the exclusive right to sell shredded wheat in the form of a pillow-shaped biscuit — the form in which the article became known to the public. That is the form in which shredded wheat was made under the basic [utility] patent [U.S. Pat. No. 548,086]. The patented machines used were designed to produce only the pillow-shaped biscuits. And a design patent [U.S. Des. Pat. No. 24,688] was taken out to cover the pillow-shaped form. Hence, upon expiration of the patents the form . . . was dedicated to the public.”[vi]

Kellogg has remained the touchstone for cases on the limits of trade dress protection, and not just for foodstuffs. Subsequent decisions have elaborated on the non-functionality doctrine without changing the basic framework.[vii]

In a more modern case, Sweet Street Desserts, a “Blossom Design” for a round, single-serving, fruit-filled pastry with six folds or petals of upturned dough was held to be functional and, accordingly, unprotectable as trade dress because the product’s size, shape, and six folds or petals of upturned dough were all essential to the product’s ability to function as a single-serving, fruit-filled dessert pastry.[viii] Only incidental, arbitrary, or ornamental product features that identify the product’s source are protectable as trade dress. Chudleigh’s trade dress Reg. No. 2,262,208 was cancelled.[ix]

Trade Dress Reg. No. 2,262,208

In Ezaki Glico v. Lotte, the non-functionality requirement was assessed in connection with Ezaki Glico’s POCKY® treats—thin, rod- or stick-shaped cookies partially coated in chocolate (with optional nuts)—and Lotte’s competing PEPERO® treats.[x]

The core dispute was how to define “functional” for product configuration trade dress. Ezaki Glico argued a narrow reading, equating “functional” with “essential.” The court disagreed, reading Supreme Court precedent to say that product configuration features need only be useful to be functional. That is, a product shape feature is “useful” and thus “functional” if the product works better in that shape, including shape features that make a product cheaper or easier to make or use. The 3rd Circuit held that a product feature being “essential to the use or purpose of the article or if it affects the cost or quality of the article”[xi] is merely one way to establish functionality.[xii] A product feature is also unprotectably functional if exclusivity would put competitors at a significant, non-reputation-related disadvantage.[xiii] The rejection of a narrow reading of the functionality doctrine echoes cases in other circuits characterizing the Supreme Court’s TrafFix case as setting forth two ways to establish functionality.[xiv] There are several ways to establish functionality that are not limited to merely “essential” product features.

Functionality in the trade dress context is commonly assessed through the following types of non-dispositive evidence, as summarized in Ezaki Glico:

“First, evidence can directly show that a feature or design makes a product work better…. Second, it is ‘strong evidence’ of functionality that a product’s marketer touts a feature’s usefulness. Third, ‘[a] utility patent is strong evidence that the features therein claimed are functional.’ Fourth, if there are only a few ways to design a product, the design is functional. But the converse is not necessarily true: the existence of other workable designs is relevant evidence but not independently enough to make a design non-functional.”[xv]

There was evidence of practical functions of holding, eating, sharing, or packing the POCKY treats. Ezaki Glico’s internal documents showed a desire to have a portion of the stick uncoated by chocolate to serve as a handle. The court also noted how the size of the sticks allowed people to eat them without having to open their mouths wide and made it possible to place many sticks in a package. Ads for POCKY treats also emphasized the same useful features. Ezaki Glico proffered nine examples of partially chocolate-coated treats that do not look like POCKY treats, but the court found that evidence insufficient to avoid the conclusion that every aspect of POCKY treats is useful.

Finally, the court concluded that Ezaki Glico’s utility patent U.S. Pat. No. 8,778,428 for a “Stick-Shaped Snack and Method for Producing the Same” was irrelevant. The court’s rationale for that conclusion, however, is rather unconvincing. The utility patent was applied for in 2007, with a 2006 Japanese priority claim, which was long after Ezaki Glico began selling POCKY treats in the U.S. in 1978, and also long after Lotte began selling the accused PEPERO treats in 1983 and the first explicit allegations of misconduct in 1993. That patent was also still in force (i.e., unexpired). The utility patent corresponded to an “ultra thin” version of POCKY treats and Ezaki Glico argued that its patent addressed only one of many embodiments covered by its trade dress.

The lower court discussed utility patent disclosures regarding stick warping formulated like a problem-solution statement[xvi]—somewhat akin to inventive step (obviousness) analyses in European patent practice. But unmentioned was how the patent’s disclosed stick holder necessarily produces a partial chocolate coating.[xvii] The 3rd Circuit’s reasoning about the irrelevance of the utility patent is superficial to the point of being mere tautology. The appellate opinion did not address Kellogg’s statement that the form in which a food article was made under an expired “basic” patent was relevant to trade dress eligibility or other circuits’ cases that deemed a prior manufacturing method patent to be relevant. Moreover, the court did not address the way mere descriptiveness of just one good bars registration of a trademark for an entire group of goods encompassing additional, different goods.[xviii] Whether a later-filed patent can ever provide grounds to cancel an earlier trade dress registration for functionality is a question the court essentially avoided deciding.

Something else not discussed in Ezaki Glico was the 3rd Circuit’s decision nearly a century ago in the Eskimo Pie case.[xix] There, the validity of U.S. Pat. No. 1,404,539 on the original ESKIMO PIE® chocolate-covered ice cream treat was at issue. The court held the utility patent invalid, reasoning with regard to claim 6 (in which the core and casing form a “substantially rectangular solid adapted to maintain its original form during handling”) that “[t]here is no invention in merely changing the shape or form of an article without changing its function except in a design patent.”[xx] The rectangular solid shape was found non-functional and therefore unable to distinguish the prior art in a utility patent claim. The lower court had already pithily reached these same conclusions:

“The gist of the invention, if there be one, is in sealing a block of ice cream in a sustaining and self-retaining casing of chocolate. A rectangular piece of ice cream is coated with chocolate…. All that the patentee does is to take a small brick of ice cream and coat it with chocolate, just as candies are coated. [In the prior art,] Val Miller took a round ball of ice cream and coated it, just as candies are coated. In one case the ice cream is round in form, and in the other case it is rectangular. In both cases there is a sustaining and self-retaining casing, sealing the core of ice cream…. There is no invention in form alone.”[xxi]

Front page of U.S. Patent No. 1,404,539
U.S. Pat. No. 1,404,539

In a fascinating Wired article from 2015, Charles Duan located correspondence with the inventor’s patent attorney and other pertinent historical information in museum archives.[xxii] Duan highlighted how the invention, if anything, was really about the particular formulation of chocolate that allowed it to work effectively as a coating on a frozen ice cream treat, while the patent contains no disclosure in that regard and its claims were intended to be preemptive.[xxiii] Invalidation of the ESKIMO PIE patent opened the door for the KLONDIKE® ice cream treat, introduced in 1928, which was later the subject of an 11th Circuit trade dress case about product packaging (as opposed to product configuration) for a wrapper with a pebbled texture, images of a polar bear and sunburst, bright coloring, and square size that, in combination, were held non-functional.[xxiv]

Courts have tended to be more lenient on (food) packaging trade dress when it comes to functionality.[xxv] This held true when the 11th Circuit later found the unregistered product design of DIPPIN’ DOTS® multi-colored flash-frozen ice cream spheres/beads to be functional and thus ineligible for trade dress protection.[xxvi] An unexpired utility patent (U.S. Pat. No. 5,126,156)—later held invalid and unenforceable[xxvii]—was specifically cited as evidence of functionality of the product design, along with judicial notice that certain colors connote ice cream flavor.[xxviii]

So, in 1929, the 3rd Circuit ruled that the configuration of an ESKIMO PIE treat was ornamental and non-functional, and therefore unpatentable in a utility patent; whereas, in 2021, the Third Circuit ruled that the configuration of a POCKY treat was functional, and therefore ineligible for trade dress protection. How can these decisions be reconciled?

The only way to square these cases is to say that “functionality” in the trade dress context means something legally different than in the patent context. So, an ice cream treat’s shape/configuration was insufficiently functional to support a utility patent claim though a cookie treat’s shape and configuration was too functional (useful) to support trade dress protection. But courts and other commentators often stop well short of explaining why “functionality” differs in these two contexts, or what specific evidence would differ—aside from the separate need to prove inherent or acquired distinctiveness to establish trade dress rights.[xxix]

The ultimate conclusions in the two cases, however, are very consistent in seeking to limit overreaching IP assertions. The functionality doctrine for trade dress has long been used to scrutinize attempts to secure a potentially perpetual trademark monopoly on product feature(s) that consumers desire in the product itself apart from any unique but optional source-identifying function(s) of product configuration—as well as manufacturers’ concerns about ease and cost of manufacturability. In the patent context, utility requirements at least implicitly revolve around the technological arts rather than aesthetic, saleability, and product source identification concerns—those might be called functions but they are not the type of inventive functions that are eligible for utility patent protection.

But the courts have yet to make explicit the precise role, if any, of the relevant consumer’s perspective in this analysis, which would seem to be a legitimate inquiry in the trade dress context in a way it would not be in the utility patent context, for instance. Admittedly, the “ordinary observer” test used for infringement of design patents blurs this distinction somewhat, especially given that one appeals court has held that conflation of the trademark likelihood-of-confusion test and the design patent ordinary-observer test is harmless error.[xxx] But evidence of non-reputational consumer desires, such as a consumer survey or similar expert testimony, would appear to be rather unique to product configuration trade dress considerations and in closer cases might not always be answered or rendered unnecessary by the admissions or conduct of the alleged trade dress owner.

Certainly, many trade dress product configuration cases do turn on admissions or statements (such as ads) by the owner that indicate functionality or the failure of the owner to meaningfully rebut the persuasive articulation of functionality readily observable in the product itself. Additionally, parties aggressively enforcing trade dress have often also pursued or obtained another form of protection, such as a patent, and statements made in (or during the prosecution of) a patent on the same or similar subject matter can be relevant to trade dress functionality.[xxxi] The Supreme Court has gone so far as to explicitly note that invoking trademark rights as patent rights expire is suspicious enough to create “a strong implication” the party is seeking to improperly extend a patent monopoly and that summary disposition of anticompetitive strike suits is desirable.[xxxii] This means consumer surveys or the like should not become routinely necessary. Yet cases may arise where consumer perceptions of functionality (or usefulness) are not immediately apparent from the product configuration itself, or the plaintiff has not made damaging statements, making survey evidence informative in the absence of more straightforward grounds for assessing functionality. This seems like a potential additional (fifth) category of functionality evidence not spelled out in cases like Ezaki Glico.


Foodstuff product configuration trade dress disputes provide an excellent case study of how courts have sought to preserve consumer access to functional product features, as well as producer access to easy and economical manufacturing techniques. After all, the purpose of trademark law in general is supposed to be about helping consumers identify whether something originates from company A or company B, for instance, but it is not meant to give anyone a monopoly on that something itself. Unless product configurations are relatively easily avoided by competitors making basically the same products, assertions of trade dress protection in pure product configurations have often been rejected. While courts remain sensitive to potential confusion over a product’s source, valid product configuration trade dress rights, as a matter of branding, should include a prominent, non-functional feature related to reputation that does not significantly diminish consumer enjoyment or ease of manufacturability.[*]

A version of this article previously appeared in Bench & Bar of Minnesota Magazine Digital Edition Vol. LXXVIII No. XI (December 2021).

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Austen Zuege is an attorney at law and registered U.S. patent attorney in Minneapolis whose practice encompasses patents, trademarks, copyrights, domain name cybersquatting, IP agreements and licensing, freedom-to-operate studies, client counseling, and IP litigation. If you have patent, trademark, or other IP issues, he can help.


[i] U.S. Const., Art. I, § 8, cl. 8.

[ii] See Graham v. John Deere Co. of Kansas City, 383 U.S. 1, 5-6 (1966); Darcy v. Allein, 11 Co. Rep. 84, 77 Eng. Rep. 1260 (K. B. 1603).

[iii] Shredded Wheat Co. v. Humphrey Cornell Co., 250 F. 960 (2d Cir. 1918).

[iv] Id. at 964.

[v] Kellogg Co. v. National Biscuit Co., 305 U.S. 111, 122 (1938); see also Graeme B. Dinwoodie, “The Story of Kellogg Co. v. National Biscuit Co.: Breakfast with Brandeis,” Intellectual Property Stories (Dreyfuss and Ginsburg, eds., Foundation Press, 2005).

[vi] Kellogg, 305 U.S. at 120-21; see also “Henry Perky: Patents,” Wikipedia (last visited Jan. 7, 2021); U.S. Des. Pat. No. 48,001.

[vii] See TrafFix Devices, Inc. v. Marketing Displays, Inc., 532 U.S. 23, 28-32 (2001); Wal-Mart Stores, Inc. v. Samara Brothers, Inc., 529 U.S. 205, 213-16 (2000); Qualitex Co. v. Jacobson Prods. Co., 514 U.S. 159, 164-65 (1995); Two Pesos, Inc. v. Taco Cabana, Inc., 505 U.S. 763, 771,775 (1992); Bonito Boats, Inc. v. Thunder Craft Boats, Inc., 489 U.S. 141 (1989); Inwood Labs., Inc. v. Ives Labs., Inc., 456 U.S. 844, 850 n.10 (1982); Sears, Roebuck & Co. v. Stiffel Co., 376 U.S. 225, 228-32 (1964); Compco Corp. v. Day-Brite Lighting, Inc., 376 U.S. 234, 238 (1964); see also Scott Paper Co. v. Marcalus Mfg. Co., Inc., 326 U.S. 249, 255-57 (1945).

[viii] Sweet Street Desserts, Inc. v. Chudleigh’s Ltd., 69 F. Supp. 3d 530, 532-33 and 546-50 (E.D. Pa. 2014) aff’d 655 F. App’x 103 (3d Cir. 2016); see also 15 U.S.C. § 1064(3).

[ix] Sweet Street Desserts, Inc. v. Chudleigh’s Ltd., No. 5:12-cv-03363 (E.D. Pa. Jan. 15, 2015) aff’d 655 F. App’x 103.

[x] Ezaki Glico Kabushiki Kaisha v. Lotte Int’l Am. Corp., 986 F.3d 250 (3d Cir. 2021) cert denied 595 U.S. ___ (Nov. 1, 2021).

[xi] Qualitex, 514 U.S. at 165 (quoting Inwood, 456 U.S. at 850, n.10).

[xii] Ezaki Glico, 986 F.3d at 257; accord PIM Brands Inc. v. Haribo of Am. Inc., No. 22-2821 (3d Cir. Sept. 7, 2023) (alleged trade dress of wedge shape and red/white/green color scheme made watermelon candy identifiable and reminiscent of a watermelon wedge and was therefore functional and unprotectable, with Principal Register registration ordered to be cancelled; “[f]unctionality is not a high bar” and “[e]ven if the design chosen both promotes a brand and also ‘makes a product work better,’ it is functional and unprotectable.” (citing Ezaki Glico, 986 F.3d at 258)); cf. Sulzer Mixpac AG v. A&N Trading Co., 988 F.3d 174, 182-84 (2d Cir. 2021) (color-coding to denote size of dental mixing tips improved the operation of the goods, which affects their quality, and therefore was functional and unprotectable as trade dress even though not essential).

[xiii] Ezaki Glico, 986 F.3d at 257 (quoting TrafFix, 532 U.S. at 32).

[xiv] Dippin’ Dots, Inc. v. Frosty Bites Dist., LLC, 369 F.3d 1197, 1203 (11th Cir. 2004); Groeneveld Transp. Efficiency, Inc. v. Lubecore Int’l, Inc., 730 F.3d 494, 506-09 (6th Cir. 2013); Schutte Bagclosures Inc. v. Kwik Lok Corp., 193 F. Supp. 3d 245, 261-62 (S.D.N.Y. 2016) aff’d 699 F. App’x 93, 94 (2d Cir. 2017).

[xv] Ezaki Glico, 986 F.3d at 258 (internal citations omitted); but see James J. Aquilina, “Non-Functional Requirement for Trade Dress: Does Your Circuit Allow Evidence of Alternative Designs?” AIPLA (May 5, 2020).

[xvi] Ezaki Glico Kabushiki Kaisha v. Lotte Int’l Am. Corp., No. 2:15-cv-05477, 2019 WL 8405592 at *6 (D.N.J., 7/31/2019).

[xvii] See holder (61), which holds one end of stick-shaped pastries (40) while (only) the other end is immersed in a container (62) of liquid coating material (e.g., chocolate). U.S. Pat. No. 8,778,428, FIG. 5 and col. 5, lines 15-18 & 45-50.

[xviii] See TMEP §1209.01(b) (Oct. 2018).

[xix] Eskimo Pie Corp. v. Levous, 35 F.2d 120 (3d Cir. 1929).

[xx] Id. at 122; see also, e.g., E.H. Tate Co. v. Jiffy Ents., Inc., 196 F. Supp. 286, 298 (E.D. Pa. 1961); James Heddon’s Sons v. Millsite Steel & Wire Works, 128 F.2d 6, 13 (6th Cir. 1942).

[xxi] Eskimo Pie Corp. v. Levous, 24 F.2d 599, 599-600 (D. N.J. 1928).

[xxii] Charles Duan, “Ice Cream Patent Headache,” Wired (Oct. 20, 2015).

[xxiii] Id.; cf., Alice Corp. Pty. Ltd. v. CLS Bank Int’l, 573 U.S. 208, 223-24 (2014); Mayo Collab. Servs. v. Prometheus Labs, Inc., 566 U.S. 66, 72-73 (2012).

[xxiv] AmBrit, Inc. v. Kraft, Inc., 812 F.2d 1531, 1535-38 (11th Cir. 1986), cert. denied, 481 U.S. 1041 (1987), abrogated by Wal-Mart, 529 U.S. at 216, but see The Islay Co. v. Kraft, Inc., 619 F. Supp. 983, 990-92 (M.D. Fla. 1985).

[xxv] E.g., Spangler Candy Co. v. Tootsie Roll Inds., LLC, 372 F. Supp. 3d 588, 604 (N.D. Ohio 2019); Fiji Water Co., LLC v. Fiji Mineral Water USA, LLC, 741 F. Supp. 2d 1165, 1172-76 (C.D. Cal. 2010).

[xxvi] Dippin’ Dots, 369 F.3d at 1202-07; see also 15 U.S.C. §1125(a)(3). The court incorrectly stated unregistered product configuration trade dress can be inherently distinctive, a position abrogated by Wal-Mart.

[xxvii] Dippin’ Dots, Inc. v. Mosey., 476 F.3d 1337 (Fed. Cir. 2007).

[xxviii] Dippin’ Dots, 369 F.3d at 1205-06.

[xxix] See Keystone Mfg. Co., Inc. v. Jaccard Corp., No. 03-CV-648, 2007 WL 655758 (W.D.N.Y., Feb. 26, 2007).

[xxx] Unette Corp. v. Unit Pack Co., 785 F.2d 1026, 1029 (Fed. Cir. 1986); see also Converse, Inc. v. Int’l Trade Comm’n, 909 F.3d 1110, 1124 (Fed. Cir. 2018) (calling the standards “analogous”).

[xxxi] TrafFix, 532 U.S. at 29-32; Dippin’ Dots, 369 F.3d at 1205-06.

[xxxii] Singer Mfg. Co. v. June Mfg. Co., 163 U.S. 169, 181 (1896); Wal-Mart, 529 U.S. at 213-14; see also Morton Salt Co. v. G.S. Suppiger Co., 314 U.S. 488 (1942) (misuse of patent on machine to restrain unpatented salt tablet sales); Dastar Corp. v. Twentieth Century Fox Film Corp., 539 U.S. 23 (2003) (improper trademark assertion after copyright expiration); EMI Catalogue P’ship v. Hill, Holliday, Connors, Cosmopulos, Inc., 228 F.3d 56, 63-54 (2d Cir. 2000) (“musical composition cannot be protected as its own trademark” because “[t]he creation and expression of an original work is protected by copyright law, and once an original work has been produced trademark law is not the proper means of protecting the rights in this originality”; declining to rule “that a product itself—in this case, the song—can serve as its own trademark”); Korzybski v. Underwood & Underwood, Inc., 36 F.2d 727, 728-29 (2d Cir. 1929) (election of protection doctrine bars copyright after obtaining patent: “An inventor who has applied for and obtained a patent cannot extend his monopoly by taking out a copyright . . . on what he has already diagrammatically disclosed”) accord Vacheron & Constantin-Le Coultre Watches, Inc. v. Benrus Watch Co., 260 F.2d 637, 642 (2d Cir. 1958) (“grant of a patent presupposed a dedication to the public of the disclosure, except so far as the statute specifically reserved it to the patentee”).

[*] For European perspectives on functionality issues for trade dress, see Megan Rae Blakely, “KitKat Lost Its Trade Mark Case: What You Need to Know,” The Conversation (July 31, 2018); Kirsti Knolle and Silke Koltrowitz, “Lindt Chocolate Bunny Hops Towards Victory in Trademark Battle,” Reuters (July 29, 2021); César J. Ramírez-Montes, “The Elusive Distinctivenes of Trade Dress in EU Trademark Law,” 34 Emory Int’l L. Rev. 277 (2020); see also Michiel Rijsdijk, “The Netherlands’ Tripp Trapp Chair Saga,” INTA Bulletin, Vol. 76, Issue 30 (Aug. 4, 2021).

Patents Q&A

What Are the Requirements for Patentability?

3 Basic Requirements

In order to get a patent for an invention it must be patentable. There are three basic requirements for patentability:

An applicant gets to define an invention in “claims” of a patent application. Patentability is always analyzed by looking at those claims. If a claims fails any requirements for patentability, then the applicant is not entitled to a patent on it. Though it is still possible to consider the patentability of an invention in an informal sense even before any claims are written. However, judgments about patentability (or validity) can be challenging and subject to dispute.

There are other patentability requirements, such as enablement and definiteness. But these other requirements go more to the form and content of a patent application. You might even say those other requirements are about an application being presented in a patentable form rather than being about the patentability of an invention in the abstract. Only the three basic requirements are discussed below.


Utility is about the nature of the invention itself. If you write a novel it can never be patented. That is because it is not “useful”. So it fails the utility requirement. But that is an easy example. Nobody thinks of the contents of a book as an invention. So what “useful” inventions are patent-eligible? U.S. patent law states, “Whoever invents or discovers any new and useful process, machine, manufacture, or composition of matter, or any new and useful improvement thereof, may obtain a patent therefor . . . .” Despite that broad definition, laws of nature, natural phenomena, and abstract ideas are not patent-eligible. A claimed invention that is nothing more than one of those things is “preemptive” and fails the utility requirement.

Most man-made inventions have utility. Questions about patent eligibility (utility) tend to arise most for software, methods of medical diagnosis and treatment, biotechnology/life sciences, and business methods. In those areas, the way a patent application and its claims are drafted tends to get a lot of scrutiny.

For design patents, ornamentality is required instead of utility. Ornamentation can be (a) the shape of an article itself, (b) something applied to or embedding in an article, such as surface ornamentation, or (c) a combination of the first two possibilities. Also, the ornamentation must be applied to an “article of manufacture”. A picture standing alone is not eligible for design patent protection. But aside from ornamentality replacing the utility requirement, both of the other patentability requirements (novelty and non-obviousness) still apply to designs.


Novelty means that an invention cannot be identical to something already known. For instance, if a claimed invention was already disclosed in someone else’s earlier patent then it lacks novelty. In this respect, assessing novelty involves a comparison that first requires an understanding of what came before. Lack of novelty is commonly referred to as “anticipation”.

However, only certain documents and information can be considered for patentability. Whether or not something qualifies as “prior art” against a given patent claim must first be established. Usually the question is whether a given patent or publication is old enough to be considered prior art. U.S. patent laws set forth somewhat complicated definitions of prior art and novelty. But, in general, earlier patents, printed publications, public uses, and sales can all potentially qualify as prior art. Even inventors’ own past actions and writings can count as prior art against them.

Sometimes novelty is described as “absolute novelty” because inventors are charged with constructive knowledge of all prior art. In other words, it doesn’t matter whether the inventor actually knew about the relevant prior art or not. The novelty requirement bars more than inventions copied from elsewhere. Even obscure disclosures about inventions that are not commercial available—and may never have been—may bar patentability.

Novelty also takes into account inherent teachings. It goes beyond explicit, literal prior art disclosures to further encompass what is unstated but necessarily implied. So, for example, if the prior art structure is the same as what is claimed, then previously unappreciated properties and benefits of that structure are likely inherent even if unstated in an earlier patent.

Novelty and anticipation always refer to what was (explicitly or inherently) disclosed in a single prior art reference. This distinguishes novelty from obviousness, which is discussed below.

Non-Obviousness (or Inventive Step)

Non-obviousness means an invention must represent a significant advance over what was already known in order to be patentable. U.S. patent laws say that even if the claimed invention has novelty, it will not be patentable “if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious . . . to a person having ordinary skill in the art to which the claimed invention pertains.” Many other countries use the term “inventive step” to refer to the concept of non-obviousness.

Obviousness is formally analyzed by first determining the scope and content of the prior art, the differences between the prior art and the claim at issue, and the level of ordinary skill in the relevant art. Those facts must be taken into account when drawing a legal conclusion about obviousness or non-obviousness. So-called secondary considerations for non-obviousness can also be considered. But such secondary evidence is often not available.

obviousness graphic
Conceptual Illustration of Anticipation/Obviousness/Non-Obviousness

It is possible to conceptualize obviousness as a fuzzy zone around the closest prior art. In that zone the invention is too trivial to be patentable. An invention must go far enough beyond the prior art to be worthy of a patent. Though exactly how far is hard to establish with a bright line. The main way to reach non-obviousness is to claim something that solves a technical problem in the prior art. You do need an invention and cannot merely claim the absence of the prior art or the absence of a problem. After all, patentability is about encouraging inventions that positively contribute to human knowledge. That is how this ties in to the reason patents exist.

In practical terms, patent application claims are often rejected by an examiner for obviousness based on a combination of multiple prior art patents. In those situations, no single earlier patent discloses all the features or elements of a given patent claim. But the examiner can assert that someone would have been motivated to combine or modify the different teachings of multiple earlier patents to arrive at the claimed invention (with a reasonable chance of success). These are often difficult judgments to make. And there can be a temptation to slide into hindsight bias. These are some of the reasons why obviousness is sometimes called the ultimate condition for patentability.

Have an invention you would like to patent? Have a brand you would like to register as a trademark? Concerned about infringing someone else’s intellectual property? Is someone else infringing your IP? Need representation in an IP dispute? Austen is a patent attorney / trademark attorney who can help. These and other IP issues are his area of expertise. Contact Austen today to discuss.


Patent Searching: (Almost) Everything You Need to Know

Reproduced here are materials presented at the AIPLA CLE webinar Patent Searching: (Almost) Everything You Need to Know on September 14, 2021. The presentation slides, which include links to patent searching resources available online, are available for download below.


Rather than a tutorial or “how-to” guide in the mechanics of searching, these program materials address important considerations that inform the planning, execution, and validation of all types of patent searches, including patentability, freedom-to-operate, invalidity, landscape, and due diligence searches. Readers will learn about timing considerations, budgeting and staffing models, export controls, privileges, evidentiary considerations for invalidity/patentability challenges, metrics for evaluating the effectiveness of a search, and more. This overview will be useful for those who perform searches themselves and those who outsource their searches to others.

I. Types of Patent Searches

The purpose of a patent “landscape” search is to ascertain the overall state of patents in a particular technology area.  While “state-of-the-art” is sometimes used synonymously with “landscape” here, a distinction can be drawn between a patent landscape search limited exclusively to patents and published patent applications and a state-of-the-art search that includes patent documents as well as non-patent publications and potentially also commercially-available products.  These searches are frequently used for competitive/business intelligence purposes.  Landscape searches may be limited to particular jurisdictions in some cases.  Reports and documentation for landscape searches are often focused on only high-level bibliographic information and the like and may omit detailed discussion of the content of specific patent claims.  Landscape search reports can be very basic but also can be highly elaborate with infographics and other more elaborate visual elements aimed at an audience of businesspeople—especially higher-level executives—rather than patent attorneys. 

Landscape searches are exploratory searches performed for business-related purposes and they are not legally required. 

A patentability search identifies potential prior art against a particular invention, and is performed in order to assess the likelihood that a patent would be granted on the invention and the potential scope of allowable/patentable subject matter.  They allow more informed judgments as to whether the costs and effort of a patent application will be worthwhile.  Results of a patentability search can also be utilized by the person(s) preparing a patent application on the invention to improve the quality of the application through better awareness of the closest prior art.[1]  The patentability search, as such, is the gathering of relevant prior art for purposes of a patentability analysis, which involves legal judgments beyond mere searching effort. 

The scope of a patentability search may be based on the contents of an invention disclosure document; changes or further developments to the invention that are not contained in such a document—or are simply not explicitly identified in a meaningful way—may not be captured by the search.  Patentability searches should capture disclosures contained anywhere in a given prior art document or product, including inherent disclosures and things visible only in the drawings.  Patentability searches ideally encompass both patent documents and non-patent publications, as well as commercially available products, available anywhere in the world.  However, as a practical matter, patentability searches are usually subject to significant constraints on their scope.  Most patentability searches are budget-constrained, whether in terms of a monetary budget or a time budget (e.g., needed by tomorrow).  Moreover, some patentability searches might be limited to only a search of patent documents, or in a database that covers only certain key jurisdictions or non-patent literature (NPL) publications.

Patentability searches are exploratory searches performed to enable a legal evaluation of patentability as well as to inform business decision-making but they are not legally required by the USPTO before filing a patent application.  Sometimes a patentability search is combined with a freedom-to-operate (FTO) search. 

Due diligence searches are performed in various contexts where it is desired to verify the current ownership/assignment of given patent(s) or application(s) and to identify potential clouds on title, to establish family and other bibliographic data, and to vet corporate mergers & acquisitions (M&A) that involve patent assets and other patent licensing or acquisition opportunities (e.g., to assess scope, validity, valuation).  In the due diligence context, searching may be focused on ascertaining ancillary data for a known or limited universe of patents.  Due diligence searches may shade into other types of searches.  For instance, a freedom-to-operate search may be performed to assess infringement risks associated with a product line or technology acquisition.  Also, sometimes invalidity searches are performed during acquisitions in order to assess the strength of acquisition targets or even to proactively attack the patents to create leverage to drive down acquisition cost.  Another situation where due diligence searches can be utilized is in preparation for enforcement. 

Due diligence searches can be considered exploratory searches.  There is generally no affirmative legal duty to perform a due diligence patent search.[2] 

An FTO search, also called a “clearance” or “right-to-use” search, is used to identify patents and pending patent applications that pose potential infringement risks associated with a particular product or process.[3]  “Contract clearance” searches are a subset of FTO searches for compliance with contract provisions.  The FTO search, as such, is the gathering of relevant patents and applications for purposes of an FTO analysis, which involves legal judgments beyond mere searching effort. 

The scope of an FTO search must generally first be ascertained by performing a “feature identification” or “product decomposition” analysis to identify discrete, potentially patentable features to be searched.  FTO searches focus on the claimed subject matter, and need not address non-patent materials.  Moreover, FTO searches may be limited to only jurisdictions where the product or process will be made, used, sold, or offered for sale—bearing in mind that contributory or induced infringement risks may expand the list of relevant jurisdictions in some situations. 

In order to have a reasonable basis to rule out potential infringement risks an FTO search must be reasonably comprehensive and reliable, meaning that FTO searches should ideally not be subject to arbitrary constraints.  Though in some situations an FTO search on particular feature(s) might be deferred or foregone if there is a reasonable basis to believe those feature(s) will present relatively low risk of infringement, such as where the particular feature of the product or process in question is confidently known to have been in commercial use (identically) for more than twenty years—making any recent patents directed to such a feature likely to be invalid. 

FTO searches are defensive searches performed to enable a legal evaluation of infringement risk.  Sometimes an FTO search is combined with a patentability or due diligence search.  A potential infringer is not subject to an adverse inference for failing to affirmatively conduct an FTO search and/or seek an opinion of counsel.[4]   Though the range of options to avoid liability is much greater if you find a potentially problematic patent before it finds you. 

An invalidity search is used to identify prior art that renders one or more claims of a given patent invalid.  Invalidity searches are often used to develop an invalidity defense to an allegation of infringement and/or to help establish a good faith belief in invalidity to avoid a charge of willful infringement through an advice of counsel defense.[5]  Depending on the context, such as for a challenge at the USPTO, the word “unpatentability” may apply instead of “invalidity”, in a strict sense.  In other countries, terms like “nullity” or “opposition” might be used instead of “invalidity” or “unpatentability”.  An invalidity/unpatentability search can further be used to identify prior art against one or more claims of a pending patent application, for potential use for a third-party pre-grant submission or third-party observations made to the relevant patent office. 

Invalidity searches should seek relevant disclosures contained anywhere in prior art documents or products, including inherent disclosures and things visible only in the drawings.  Invalidity searches ideally encompass both patent documents and non-patent publications, as well as commercially available products, available anywhere in the world.  Though the status of certain activities or documents as “prior art” may vary.  Research into commercially available products may take on the character of an investigation more than an exercise in database searching.  Because invalidity searches may be performed in high-stakes situations, they are often the most involved and comprehensive searches, because the extra effort and expense is justified.  For example, it may sometimes be worthwhile to commission multiple invalidity searches in different languages. 

Invalidity searches are defensive searches performed to enable a legal defense to be developed against an actual or potential allegation of infringement. Although invalidity searches are not legally mandated per se, they are generally necessary in a practical sense in order to develop and assert an invalidity defense or affirmatively challenge validity/patentability.[6] 

II. Timelines

Searches can be informally divided into two general categories: prospective and reactive

Prospective searches include landscape, patentability, and FTO searches.  The prospective category refers to a given search being performed in advance of some key decision point or action, such as before the launch of a product (FTO search), or the preparation and filing of a patent application (patentability).  Prospective searches inform such decisions and actions and, accordingly, should be timed so that completed search results are available to be analyzed prior to any deadlines for a decision or action. 

With respect to FTO searches, in particular, searching may be performed on an ongoing or periodic basis, such as to monitor patenting activity by particular competitor(s) and/or in particular technology area(s).  Additionally, there may be a need to watch the prosecution status of certain pending patent applications, to ascertain the scope of what, if anything, is later allowed or granted.  Some patent database tools include features to help facilitate various ongoing monitoring efforts.  Furthermore, FTO searches may need to be updated at a later point in time.  For instance, changes in product configuration may arise (e.g., manufacturability concerns arise close to a schedule product release that prompt a slightly different product configuration, or a new version of a product is developed years later) and require a new search—or at least a renewed analysis of existing search results.  Additionally, because patent applications are typically published 18 months from filing, though potentially only upon grant, at the time of any given FTO search there may be relevant but unpublished patent applications pending that can only be captured by a subsequent search. 

Invalidity and due diligence searches are reactive, in the sense that they are performed after some concrete or potential infringement risk comes to light or some need for confirmation arises.  There may still be deadlines for filing an answer to a complaint before a district court, filing a patent office challenge (e.g., PGR, IPR, opposition, observation), completing an M&A deal, or the like that constrains aspects of an invalidity search timeline.  One benefit of conducting FTO studies is that early identification of potentially problematic patents can help provide a longer time period for invalidity searching. 

III. Budgeting and Staffing

In the most general sense, patent searches are about solving information-retrieval problems.  While it is always (theoretically) desirable to conduct a “perfect” search, with hypothetical 100% recall and 100% precision, in the real world all searches are subject to constraints and a “perfect” search is not possible.  Those constraints may be in the form of deadlines or budget limits.  For instance, few if any patentability searches have an unlimited budget, and most operate on the premise of making reasonable efforts within some predetermined time and budget limits.  Any given search also usually includes express or implied limits on the databases, jurisdictions, and languages in which a search is conducted. 

The project management discipline has developed something called the “iron triangle”, which can be applied to the searching context.  In its most basic form, the “iron triangle” has three components: cost, speed, and quality.  Project management says you must pick only two of the three on any given project—you cannot have all three, even though those requesting searches often want all three.[7]  But the two factors selected will generally vary depending on the type of search, with patentability searches often sacrificing quality in order to achieve cost and speed objectives and with FTO and invalidity searches accepting slower timelines and/or greater costs in order to maintain high quality, for example.  Also note that if you do not pick two of the three, someone else will pick them for you.

For any given search, the amount of effort required varies depending on the density of patenting or publication in a given technology area.  Though at the beginning of a search that density may be unknown—usually this is only something that can be estimated well if numerous searches have previously been performed on related subject matter. 

graphic showing continuums of patent/publication density and search cost/effort
Continuums of Patent/Publication Density and Searching Cost/Effort

Searches can be performed by dedicated non-attorney searchers.  Though attorneys can perform searches themselves and it may be surprising to some that attorney-conducted searches may be more cost effective in some situations because legal analysis and searching per se can be done concurrently and features of search tools can help aid the legal analysis (e.g., by informing the attorney which particular keyword(s) returned a given reference and highlighting that term in a searchable document).  Prize/award-based “crowdsourcing” is another approach, usually best suited to invalidity searches. 

When retaining a person or firm to conduct a search, another common decision point is choosing between an experienced subject-matter expert (e.g., an in-house staff person) versus a “hired gun” (e.g., a professional searcher with little or no knowledge of the specific subject matter).  Because experience has a cost this is generally a cost vs. quality tradeoff. 

Export controls and similar provisions (e.g., ITAR, sanctions, DoD tranches) may prohibit (or limit) who can perform a given search, which may prohibit outsourcing a search abroad.[8]  For conventional export controls, the Commerce Control Lists (CCLs) establish what is subject to export restrictions.  The “EAR99” CCL designation generally applies to low-tech consumer goods that do not require export license in many situations.  However, “dual-use” export controls apply to things that have both military and non-military applications, and can be esoteric.  The Wassenaar Arrangement Control Lists also provide guidance on what is currently implicated by dual-use export controls.  Reexports and retransfers are also prohibited.[9]  As an example of reexport, consider that a person from a foreign country sends technical information to a searcher in the USA; the searcher may not be able to send (reexport) the same information back to that same person—here you can think of the USA like a “fly trap” for export-controlled information.  Lastly, even if you are operating entirely within the USA, a “deemed export” involves providing controlled information to a non-Green Card foreigner (or non-protected person) located in the USA.  That is, providing information to a foreigner physically located in the USA is “deemed” to be the same as exporting that information to the foreigner’s home country. 

IV. Resources for Conducting Searches

A. Introduction

It is often said that patent searching is more an art than a science.  There is no one-size-fits-all formula for conducting effective and reliable searches.  While searching does not become “easy” simply because you wish it was easy, and there is a learning curve, it is a skill that can be learned.  Fortunately, there are many resources available on the mechanics of how to conduct searches in the patent context.[10] 

There are many patent searching tools available, most of which are computer databases accessible via the Internet, though patent offices and affiliated libraries do offer some additional on-site-only resources for patent searching.[11]  Search engine functionality varies widely, with advanced features like proximity searching, bulk export of selected data, and highlighting of keywords within search results available only with certain tools.  In general, paywalled proprietary databases tend to have bells and whistles that can be helpful and save time.  Though user licenses can be significant and searchers who perform searches only occasionally will likely find yearly license fees cost-prohibitive. 

Whatever particular tool is used it is important to familiarize oneself with the scope of coverage (which jurisdictions are covered? what time periods are full-text searchable?) and the database’s search syntax, which refers to the particular operators used to command the search engine to run queries in particular ways.  While basic Boolean operators like “AND” and “OR” tend to be fairly universal, some tools require those operators to be in all caps.  More advanced operators like proximity commands or wildcard characters can be very different from one tool to the next.  Search syntax matters because a given search string or query inputted verbatim into different database tools may be parsed quite differently. 

B. Principal Database Searching Methods

While it is still possible to search for information by visiting a library and locating relevant physical publications, most patent-related searching today is performed using computer databases, most of which are now accessible via the Internet.  Computer databases useful for patent searches can be queried in a number of different ways that are ultimately a function of both the database’s search engine and metadata structure and content. 

Keyword searching, which is generally synonymous with Boolean searching, involves inputting keywords and Boolean operators (“AND”, “OR”, etc.) into a keyword string or query that the database’s search engine parses against its contents.  Database search engines have vastly different capabilities.  For instance, proximity operators are available with some databases that can be used to greatly increase the precision of keyword-based queries.  Moreover, some databases are only full-text searchable back to a particular historical date.  But be aware that not all databases or search engines are perfect, even the most full-featured tools.  A database populated by text obtained through optical character recognition (OCR) may contain errors that frustrate efforts to use the database’s search engine.  Databases that utilize machine translations of foreign patent documents for search queries may produce unreliable or unexpected machine translations in some instances.  Also, and perhaps less widely known, is that database providers may parse keyword strings in ways that deviate from what a searcher has inputted in given query.  For instance, in order to manage server computer hardware loads, to “enhance” searches, or for another reason, some search engines will include automatic thesaurus and/or pluralization functions or will parse defined phrases with spaces in between characters or as proximity searches (without the user inputting proximity operators).  Such features may increase recall but at the same time may decrease precision.  Conversely, some search engines may limit proximity searches to individual paragraphs, omitting from search results the presents of terms that are as proximate as specified but in two different paragraphs, which may reduce recall. Thesaurus functions can be helpful but cannot be relied upon exclusively.  Not only are the thesaurus lists generally hidden within a “black box” of the database software, but they often are inadequate to capture variations in technical terms used in the patent context.  For instance, an automatic thesaurus is unlikely to recognize that while “shopping cart” is a term used commonly in the USA, in Great Britain and Australia the term “shopping trolley” is used instead, or be able to ascertain whether “backhoe” and “excavator” are synonyms within the context of a given patent search.  Translations can also be a factor here.  For that matter, patentees can act as their own lexicographer.  So, a search for automatic license/number plate recognition (ALPR/ANPR) tools using conventional terminology may not locate a patent that describes such a tool as a “parkulator” (a completely invented word).[12] 

Classification searching involves reviewing patent documents according to subject-matter classifications made by patent offices.  Historically, before the advent of computerized databases, searching hard copies of patent documents by classification (stored in “shoes” at the USPTO) was the only way to search patents.  Today, there are a number of different classification systems currently in use, as well as ones that are no longer in use but can still be utilized in some situations.  The main classification systems currently in use are the International Patent Classification (IPC) system, the Cooperative Patent Classification (CPC) system, the Japanese File Index/Facet (FI) and File Forming Term (F-term) systems, and the Locarno system for design patents (and industrial designs).  The main discontinued classifications that may still have some value are the U.S. Patent Classification (USPC) system and the European Patent Classification (EPC) system, both of which were retired by the end of 2014.  While patent offices have made efforts to re-classify old patent documents under the current classification systems, the nature of differences between the old and new classification systems means that there is at most a statistical correspondence between the two that varies for different subject matter areas. 

In general, patent classification systems establish a taxonomy that includes multiple levels of detail, with highest-level classes and then multiple sub-classes within them (plus main groups/subgroups for the IPC).  Manuals or guides are available explaining these taxonomies, including descriptions of the subject matter that each class/subclass is intended to cover.  Classifications are assigned to individual patent documents by examiners, generally at an initial or pre-examination stage.  Because the process of classification necessarily involves certain judgments, classifications can be prone to human error.  Moreover, even in the best of circumstances, classifications are never perfect.  For instance, at any given point in time classification systems may not recognize certain emerging technology areas in the sense that there may not be specific sub-classes in which to categorize such emerging technologies.  Also, there may be subtle disclosures, such as things shown only in figures and/or left up to implication in the text, that may not be completely captured by a given patent office’s classifications.   And yet, classifications can be a useful tool for patent searching.  It is possible to combine classifications with particular keywords/terms as part of Boolean searches, which can be a powerful strategy to increase the precision of queries.

Forward and backward searching refers to searching references that are cited in the “references cited” section of a given relevant patent (backward searching) or searching for later patents in which the “references cited” section cites back to a given relevant patent (forward searching).  The essence of forward and backward searching is that you begin with one or more patent documents that you have already determined to contain relevant subject matter and then you piggyback on prior searches that others have performed in relation to other patents, leveraging the past efforts of others to compile groupings of technologically-related references.  In other words, forward and backward searching treats citations within and back to a given relevant patent as a kind of quasi-classification system. But forward and backward searching can never be the initial starting point for a search, because you must begin with at least one relevant patent—ideally the most relevant patent(s) you could find through other avenues.  Yet forward and backward searching can sometimes be the most effective method for increasing search recall. The same principles can be applied to citations and bibliographies in non-patent literature.

Other available patent searching tools utilize natural language searching, semantic searching, machine learning, artificial intelligence (AI), or the like.  Typically, such search tools utilize some type of proprietary algorithms to parse and execute search queries.  With natural language, semantic, or AI searching, the general idea is often that a searcher inputs words in a narrative format—unlike formal Boolean search syntax—and the tool applies its algorithms to convert those inputs into one or more queries that are run against the database to produce a result set.  Of note is that the use of proprietary algorithms mean that the search tool runs these searches through what can be called a “black box”—the searcher typically has no idea what happens inside that black box and thus no real sense of what might be omitted or excluded from the result set.  Some evidence from the legal research context suggests that experienced attorneys do not trust “black box” search algorithms.[13]  There are some tools, potentially most applicable to design patent searching (or trade dress searches), in which a searcher uploads an image file and the search tool utilizes image matching software to try to locate documents containing similar images.  As of today, these patent searching tools are still “bleeding edge” technologies and there is generally a lack of independent and peer-reviewed studies to validate the effectiveness of AI (etc.) them.  Vendors frequently make claims about studies they have done themselves, though it is difficult to place any trust in such studies used for marketing purposes when often there is no disclosure of the methodology employed and vendors have strong incentives to succumb to self-interest bias.  Much of the available literature on the subject can be characterized as marketing “advertorials”.  And for that matter, because AI-powered tools almost always rely on proprietary “black box” algorithms there is no way to know how a study involving one black box relates to another black box—or even if a study of a given search tool in the past still applies to that search tool, given that changes to that proprietary tool may occur within the black box without any way for a user or investigator to know.  These concerns echo the reasons experienced attorneys do not trust black box legal research tools or with concerns over law enforcement usage of AI-powered facial-recognition tools or the like[14]—control is being surrendered over aspects of search queries to algorithms premised on undisclosed assumptions that may be important to outcomes.  Perhaps as AI-powered patent searching tools become more sophisticated they will play a larger role.  But as of today, a good rule of thumb is to rely principally on human-guided searches and utilize AI-type search tools only in a secondary sense, such as for initial “quick-start” or “drunk walk” search orientation efforts before running substantive queries, last-step search validation or auditing, or supplemental, almost “hail Mary pass” efforts to perhaps get lucky and find additional art otherwise missed through other avenues. 

C. INID and Kind Codes

“INID” is an acronym for “Internationally agreed Numbers for the Identification of (bibliographic) Data” on patents.[15]  Also referred to informally as “field codes”, these codes embody a system for the international harmonization of bibliographic data (or metadata) appearing on published patent documents, such as for the title (54), assignee name(s) (73), filing date (22), issue/grant date (45), etc. 

INID CodeData Field Content
(10)Publication/Patent Number
(22)Filing Date
(43)Application Publication Date
(45)Grant/Issue Date
(86)PCT Filing Details
Table of Selected INID “Field” Codes

These INID/field codes can be tremendously useful when fetching individual patents in another language.  For example, either by referring to a table that identifies INID code numbers and the associate data content description, or simply referring to a sample patent in a known language, the location of similar data on a foreign-language patent document can be located.  While machine translations of patent documents are now frequently available, machine translations of very old patent documents are not always available.  And many machine translation tools may be unable to reliably parse PDFs of old patent documents, though it may be possible to perform limited machine translations of just particular text—such as within a given INID field—to ascertain some basic information about a given patent document.  

Comparison of INID “Field” Codes Between Patents in Different Languages
Camera-Based Partial Machine Translation of Selected Patent INID “Field” Contents

“Kind codes” identify type of patent and generally appear as a letter or letter and number (e.g., “A1” or “B2”) immediately after the patent or publication number.[16]  The USPTO only began printing kind codes on U.S. patent documents on January 2, 2001, so older U.S. patents lack a kind code.  Some countries have different types of patents—like utility models—that do not exist in the USA.  And systems for assigning numbers to patents has, historically, not been particularly harmonized internationally. 

Perhaps most confusing to U.S. practitioners is the Japanese patent numbering system, which in the past has assigned the same numbers to different patents differentiated only by the kind code. 

Another potentially confusing practice involves the treatment of old U.S. patents that were issued without any kind code on their face to which the “A” kind code (without a numerical digit) is retroactively applied.  This is potentially confusing because WIPO kind codes “A1”, “A2”, and “A9” are currently used by the USPTO to designate published patent applications.  In other words, the old granted patent “A” designation retroactively applied in searching databases can easily be confused with the new “A1”, “A2”, and “A9” designations that apply only to published applications and never to granted patents. 

V. Metrics for Evaluating Searches

The key metrics for evaluating information retrieval effectiveness in the patent context (or other library science contexts) are “precision” and “recall”.  Recall is the proportion (%) of all relevant documents retrieved in a given search query or overall search; recall is hypothetically expressed as:

Recall = relevant documents actually retrieved divided by universe of all relevant documents

Precision is the proportion (%) of relevant documents versus irrelevant documents retrieved in a given search query or overall search; precision is hypothetically expressed as:

Precision = relevant documents retrieved divided by total relevant & irrelevant documents retreived

Put yet another way, perhaps more informally, “recall” measures how completely relevant materials have been located while “precision” measures how much unwanted or useless material has been captured.  Library science has shown that recall and precision are tradeoffs with any given search query.[17]  That is, increasing recall generally decreases precision and vice-versa

In the patent searching context, 100% recall is always desired but 100% recall is only a theoretical objective.  There is no way to know, definitively, the universe of all relevant materials against which to compare a given query or overall search.  After all, if you knew at the outset what all the relevant materials were, why would you bother conducting a search merely to confirm what you already know?  And yet, if further searching returns additional relevant results than you can retroactively determine that a prior query or set of queries had less than 100% recall.  The rub is that this aspect of ascertaining 100% recall is like the impossibility of “proving a negative”: no matter how much you have searched, you can never know for certain whether or not there is at least one additional relevant reference that you simply have not yet located.  At best, certain protocols can be employed as proxies for 100% recall (e.g., searching X number of databases for Y number of hours, finding no more relevant results after a certain number of queries or period of time, etc.) but such proxies necessarily involve certain assumptions that can always be questioned. 

When is search complete? graphic, with learning curve-like graph

Practically speaking, precision is about efficiency and reliability.  Search results that include irrelevant materials can raise questions about the reliability of the search—did the searcher not understand the specific information being sought?—and can also waste time—both in terms of requiring more efforts by the searcher but also impeding later work by anyone else utilizing imprecise, cluttered search results for a legal analysis or to make business decisions. 

Some patent searching databases assign “relevancy” scores to individual results in a given query.  Such “relevancy” scores are generally determined by proprietary algorithms baked into the database’s software.  Whether the judgments embodied in those algorithms suit a searcher’s purpose is hard to know.  Most vendors do not make public the algorithms or weighting used to assign relevancy scores.  Searchers can anecdotally attest to performing searches where the “silver bullet” prior art was assigned a low relevancy score by the database tool.  Database “relevancy” scores are not meaningful as metrics for assessing search quality.  Though they might still be useful in (theoretically) presenting voluminous query results in an order that is more helpful for review. 

VI. Evidentiary Burdens, Privileges, and Disclosure Duties

A. Evidentiary Issues for NPL References and Public Use/On-Sale Evidence

District court proceedings where invalidity is alleged follow the Federal Rules of Evidence (FRE).[18]  PTAB trials at the USPTO (PGRs, IPRs, Derivations) also generally follow the FRE.[19]  Under the FRE, a document introduced as “prior art” must satisfy rules requiring authentication and prohibiting hearsay (unless an exception applies).[20]  These evidentiary burdens are not a concern for U.S. patents and published patent applications, which as “public records” are self-authenticating (FRE 902) and fall in a hearsay exception (FRE 803(8)) to qualify them as prior art.  In practical terms, authentication/hearsay objections to foreign patents and published patent applications are unlikely—and a party bringing such objections is just going to annoy the judge.  Evidentiary issues surrounding domestic and foreign patents should really only arise in rare if not unheard-of situations where forgeries are being proffered.  But evidentiary issues for NPL references, on-sale activities, and the like cannot be taken for granted.[21]  For instance, the Federal Circuit has held that “corroboration is required of any witness whose testimony alone is asserted to invalidate a patent.”[22] 

However, during ordinary examination and reexamination lower evidentiary standards apply to NPL references and compliance with the FRE (or similar PTAB trial procedures) is unnecessary.[23]

B. Qualifying a Non-Patent Literature (NPL) Reference as “Prior Art”

In order to qualify as “prior art”, an NPL reference must be established as a “printed publication” that was sufficiently generally “publicly accessible” before the critical date—and that must be done in accordance with the hearsay and authentication requirements discussed above for district court litigation and PTAB trials.  “‘[P]ublic accessibility’ has been called the touchstone in determining whether a reference constitutes a ‘printed publication[.]’”[24]  “A reference will be considered publicly accessible if it was disseminated or otherwise made available to the extent that persons interested and ordinarily skilled in the subject matter or art exercising reasonable diligence[] can locate it.”[25]  “Whether a reference is publicly accessible is determined on a case-by-case basis based on the ‘facts and circumstances surrounding the reference’s disclosure to members of the public.’”[26]  Limited distribution, even to those skilled in the art, may not amount to “publication” unless the material is otherwise so situated that “anyone who chooses may avail himself of the information it contains.”[27]  While evidence of “indexing” can establish public accessibility, it is merely one among many ways to establish “printed publication” status.[28]

In the invalidity context, it cannot be assumed that a copyright date, printing date, Internet server upload date, or the like appearing on the face of the NPL reference will necessarily satisfy public availability evidentiary requirement.  Courts and the PTAB have rejected such arguments in numerous cases.[29]  But clear indications on or within an NPL reference evincing publication by an established publisher with traditional hallmarks of publication (ISBN, etc.) might be sufficient.  Courts and the PTAB have occasionally found such evidence sufficient, particularly when dealing with very conventional publications like a (hard copy) book from a well-known publisher or an industry standard published by a well-known standards-setting organization.[30]  Commonly, the publication of NPL materials is substantiated by testimony from a librarian who cataloged or indexed a book or magazine as of a particular date.  In those situations, merely finding a particular disclosure is not enough to qualify the NPL reference as “prior art”—it may also be necessary to locate a witness to corroborate public accessibility. 

Materials from Internet web sites constitute an important category of NPL references where hearsay concerns can be significant.  Once again, the mere appearance of a date on the face of a web page (or in the URL, etc.) will not ordinarily be sufficient to establish the web page as a printed publication that qualifies as “prior art” before a critical date.  It is possible to offer witness testimony to establish web page publication, just as with books, magazines, and the like.  But one unique avenue for satisfying evidentiary burdens to qualify a web page as prior art is to utilize archival records from the Internet Archive’s “Wayback Machine” ( or its equivalent.[31] 

Other ephemeral or temporarily displayed materials, such as posters, videos, or presentation slides temporarily displayed at trade shows or conferences, raise other unique issues regarding their status as printed publications that qualify as “prior art”.[32]  But they may qualify as prior art under various circumstances.

Also remember that standards of proof differ depending on where a validity or unpatentability challenge is lodged.  A preponderance of the evidence standard is applied at the USPTO whereas a clear and convincing evidence standard is applied in district courts.  These different standards of proof can make a difference in whether or not available evidence establishes something as “prior art”.  Some reported decisions are less than explicit about the standard of proof being applied, which may help make sense of decisions that otherwise might seem inconsistent. 

C. Privileges and Their Limits

The attorney-client privilege and work-product protections may shield certain materials from discovery.  Yet materials generated in connection with searches are not always privileged. 

Attorney-client privilege only applies to communications actually sent, and only when seeking or providing legal advice.[33]  Such communications must involve an attorney or someone acting under the supervision and control of an attorney; and just because a communication involves an attorney does not automatically mean it is privileged.  Privilege law varies across district courts and circuits but some courts have held that the acts of counsel, the general topics of discussion, and the ultimate legal conclusions are not privileged.  Moreover, communications involving in-house counsel are often scrutinized more closely and may be subject to a rebuttable presumption that they contain business rather than legal advice.[34]  In general, anything that would have to be disclosed on a privilege log in litigation is not privileged.[35]  For instance, a privilege log may need to identify patents by number, and documents found during patent infringement/prior art searches or reviewed by an expert witness might need to be identified or disclosed.[36]

Work product protection can preclude discovery of documents and tangible things that are “prepared in anticipation of litigation or for trial” by or for another party or its representative (including the other party’s attorney, consultant, or agent).[37]  Work product protections can apply to the work product of non-attorneys but will not apply where business considerations predominate (regardless of the involvement of any attorney(s)).[38]  Also, work product protection is not absolute, and can be overcome if the materials are otherwise discoverable and the party seeking discovery shows that it has substantial need for the materials to prepare its case and cannot, without undue hardship, obtain their substantial equivalent by other means.[39] 

D. Duty of Disclosure

The duty of disclosure applicable to pending U.S. patent applications may necessitate some additional steps when relevant prior art is located in a search.  “Each individual associated with the filing and prosecution of a patent application has a duty of candor and good faith in dealing with the [USPTO], which includes a duty to disclose  . . . all information known to that individual to be material to patentability . . . .”[40]  Deliberately withholding prior art material to patentability can render any resulting patent unenforceable.[41]  Anyone substantively involved[42] with pending U.S. patent application(s) who receives search results on related subject matter should consider the need to submit search results on an information disclosure statement (IDS). 

VII. Considerations for USPTO Post Grant Proceedings

Strategic and legal considerations regarding the type of post-grant challenge that might be leveled against a given patent will vary depending upon the available prior art.  For that reason, it is usually desirable to locate prior art, or at least most of it, before deciding which type of post-grant proceeding will be sought.  For example, certain types of post-grant proceedings can only be based on patents and printed publications.  Moreover, the thresholds for institution of different types of proceedings vary;[43] though one constant is that all USPTO post-grant proceedings are based on a preponderance of the evidence standard for patentability while district court actions are based on the higher clear and convincing evidence standard for invalidity.  Lastly, IPR institutions are on an all-or-nothing basis.[44] 

PTAB trials involve estoppel that bars any further challenge based on any ground the petitioner “raised or reasonably could have raised” in a prior proceeding.[45]  This amounts to a “use it or lose it” (or “cite it or forgetaboutit”) opportunity to present prior art in a PTAB trial petition for institution, and requires that essentially all prior art searching be completed before the petition is filed—and therefore, practically speaking, before a petition can be prepared by legal counsel.  The PTAB and some district courts have interpreted and applied the “raised or reasonably could have raised” standard by asking whether a skilled searcher conducting a diligent search reasonably could have been expected to discover the prior art reference in question.[46]  The PTAB has applied this standard in a rather strict and formalistic way, showing no sympathy if locating a patent document would have required “brute force” manual review of tens or hundreds of thousands of patents not in any apparently relevant class/subclass.[47]  Courts have also considered whether particular prior art, such as a physical product that is not a “printed publication” but was potentialyl was on sale or in public use, reasonably could have been raised in a PTAB trial.[48] 

On the other hand, estoppel does not arise from ex parte reexamination.  Though collateral estoppel (issue preclusion) from prior litigation can still apply to reexams.[49]  Additionally, it is more difficult to sustain the unchanging clear and convincing evidence burden for subsequent invalidity challenges in district court when the USPTO already considered the same art.[50] 

VIII. Considerations for Design Patents

For design searching, “brute force” manual review of all designs in relevant classifications is recommended.  A major reason is that design patents have so little text that keyword searching is frequently unreliable.  There is so little text that explanatory statements that normally appear in utility patents to provide an enabling disclosure for functional features is absent in design patents focused on ornamentation.  And what little text there is in design patents might use words that are not especially helpful or reliable for purposes of a keyword search.  Though initial keyword searching can still be helpful when seeking to identify relevant Locarno classifications.  Another tip is to be sure to check for alternate embodiments that are not depicted in a representative figure on the front page of the design patent (or shown in representative thumbnail views by search tool databases).  Another point to consider for design patents is that some subject matter areas may have relatively few prior art design patents, even in areas where commercial products have been sold and publicly used for decades.  In such situations it may be necessary to investigate non-patent prior art in the form of evidence of on-sale activities, etc.  Such investigations may call for a substantially different approach and timeline.  Actually, such investigations may require considerable effort to locate and authenticate suitable evidence including witnesses/declarants

Another challenge with design patent searching is that the Federal Circuit looks to the perspective of the ordinary designer (rather than the ordinary observer) for obviousness analyses and applies a two-part Durling test for obviousness.[51] 

Somewhat unique to design patents is the opportunity to present prior art for a three-way comparison between images of the asserted patent, the prior art, and the accused product in “close” cases.[52]  The burden is on the accused infringer to bring forward evidence of the closest prior art for a three-way comparison.[53] 

Photo of Austen Zuege

Austen Zuege is an attorney at law and registered U.S. patent attorney in Minneapolis whose practice encompasses patents, trademarks, copyrights, domain name cybersquatting, IP agreements and licensing, freedom-to-operate studies, client counseling, and IP litigation. If you have patent, trademark, or other IP issues, he can help.

Book available from the ABA. Includes extended treatment of patent searching techniques.


[1] See Paul C. Haughey, “Patentability Searches – Bust or Save In-house Counsel Budgets?” Lexology (April 9, 2020).

[2] E.g., Digeo, Inc. v. Audible, Inc., 505 F.3d 1362, 1369-70 (Fed. Cir. 2007) (case not exceptional [frivolous] because defendant did not establish plaintiff knew or should have known it lacked legal title due to alleged forgeries); Q-Pharma, Inc. v. Andrew Jergens Co., 360 F.3d 1295, 1303 (Fed. Cir. 2004) (reasonable belief in presumption of validity made suit nonfrivolous under Rule 11). 

[3] See, generally, Patent Freedom to Operate Searches, Opinions, Techniques, and Studies (Austen Zuege, ed., ABA 2017).

[4] 35 U.S.C. § 298; see also Knorr-Bremse Systeme Fuer Nutzfahrzeuge GmbH v. Dana Corp., 383 F.3d 1337, 1345-46 (Fed. Cir. 2004) (en banc) abrogated by In re Seagate Tech., LLC, 497 F.3d 1360, 1371 (Fed. Cir. 2007) (en banc); Seagate, 497 F.3d at 1371 abrogated on other grounds by Halo Elecs., Inc. v. Pulse Elecs., Inc., 979 U.S. ___, 136 S. Ct. 1923 (2016).

[5] See, e.g., The Sedona Conference, “Commentary on Patent Litigation Best Practices: Willful Infringement Chapter” (July 2020 Public Comment Version).

[6] There may be rare situations in which relevant prior art is already known without conducting an invalidity search, though even then a search to locate additional prior art may have value. 

[7] E.g., Mike Morrison, “The Project Management Triangle – Time, Quality, Cost – You Can Have Any Two,” (March 23, 2017).

[8] See 15 C.F.R. Part 730; 22 C.F.R. Part 120; 31 C.F.R. Part 501; Bureau of Industry and Security, “Export Administration Regulations (EAR)”; U.S. Department of State, “Understand the ITAR and Export Controls”; Krauland et al., “State Department Publishes Long-awaited ITAR Rule on Encryption and Other Excluded Activities” Lexology (Dec. 24, 2019); U.S. Dept. of the Treasury, “Sanctions Programs and Country Information”; U.S. Dept. of the Treasury, “Consolidated Sanctions List Data Files”; U.S. Dept. of Defense, “DOD Releases List of Additional Companies, In Accordance with Section 1237 of FY99 NDAA” (Jan. 14, 2021).

[9]  15 C.F.R. § 734.14; 22 C.F.R. §§ 120.19 and 120.51.

[10] E.g., Patent Freedom to Operate Searches, Opinions, Techniques, and Studies, supra; Stephen P. Harter, Online Information Retrieval: Concepts, Principles, and Techniques (1986); David Hunt et al., Patent Searching: Tools & Techniques (2007); WIPO, “Guidelines for Preparing Patent Landscape Reports” (2015).

[11] See WIPO, “INSPIRE” at <>.

[12] U.S. Pat. No. 6,243,029 B1.

[13] Brian Sheppard, “Does Machine-Learning-Powered Software Make Good Research Decisions? Lawyers Can’t Know for Sure,” ABA Journal New Normal (Nov. 22, 2016).

[14] See, e.g., Grother et al., National Institute of Standards and Technology (NIST), “Face Recognition Vendor Test (FRVT) – Part 3: Demographic Effects,” NISTIR 8280 (Dec. 2019); “What is Math Washing?,” (last visited Jan. 29, 2021); Lyle Moran, “Pretrial Risk-Assessment Tools Should Only Be Used if They’re Transparent and Unbiased, Warns ABA House” (Feb. 14, 2022).  Note also Jacques Lacan’s concept of “university discourse.”  See, e.g., Jeffrey & Dolar, “The Sting of Knowledge,” The Point Magazine, Issue 16 (April 23, 2018); Bruce Fink, The Lacanian Subject (1995), pp. 132-33.

[15] WIPO, “Standard ST.9: Recommendation Concerning Bibliographic Data on and Relating to Patents and SPCS” (June 2013); WIPO, “Standard ST.80: Recommendation Concerning Bibliographic Data Relating to Industrial Designs” (February 2004); MPEP § 901.05(b)

[16] WIPO, “Standard ST.16: Recommended Standard Code for the Identification of Different Kinds of Patent Documents” (Oct. 2016); MPEP § 901.04(a); USPTO, “‘Kind Codes’ Included on the USPTO Patent Documents” (Sept. 18, 2013).

[17] David M.W. Powers, “Evaluation: From Precision, Recall and F-Measure to ROC, Informedness, Markedness & Correlation,” 2(1) J. Machine Learning Techs. 37, 37-63 (2011).

[18] See also, generally, Evidence in Patent Cases (Dorsney, ed., Bloomberg Law 2018).

[19] 37 CFR § 42.62; see also USPTO, “Hearsay and Authentication” (Dec. 6, 2018).

[20] Article VIII – FRE 801-807: Hearsay; Article IX – FRE 901-903: Authentication; but see, e.g., 37 CFR § 42.61 (admissibility in PTAB trials). 

[21] Cf. Wi-LAN Inc. v. Sharp Elecs. Corp., 992 F.3d 1366 (Fed. Cir. 2021) (proffered evidence of infringement inadmissible at summary judgment for lack of suitable authentication; 3d Circuit law applied).

[22] Texas Digital Sys., Inc. v. Telegenix, Inc., 308 F.3d 1193, 1217 (Fed. Cir. 2002); see also Juicy Whip, Inc. v. Orange Bang, Inc., 292 F.3d 728, 741-42 (Fed. Cir. 2002) (“rule of reason” and factors for assessing sufficiency of corroboration).

[23] E.g., MPEP § 2128 (date on a document can establish its publication for examination purposes unless applicant challenges it); Ex parte Grillo-López, Appeal No. 2018-006082 at *2-3 (PTAB, Jan. 31, 2020) (precedential) (lower examination standards vs. higher IPR standards to establish publication).

[24] In re Hall, 781 F.2d 897, 899 (Fed. Cir. 1986).

[25] Medtronic, Inc. v. Barry, 891 F.3d 1368, 1380 (Fed. Cir. 2018).

[26] In re Lister, 583 F.3d 1307, 1311 (Fed. Cir. 2009) (quoting In re Klopfenstein, 380 F.3d 1345, 1350 (Fed. Cir. 2004)); see also Blue Calypso, LLC v. Groupon, Inc., 815 F.3d 1331, 1348 (Fed. Cir. 2016) (“Whether a reference qualifies as a printed publication is a legal conclusion based on underlying factual determinations.”).

[27] In re Bayer, 568 F.2d 1357, 1360, 1362 (CCPA 1978).

[28] E.g., In re Lister, 583 F.3d at 1312 (“neither cataloging nor indexing is a necessary condition for a reference to be publicly accessible.”).

[29] E.g., Samsung Electronics Co., Ltd. v. InfoBridge Pte. Ltd., IPR2017-00099,-00100, Paper 43 (PTAB, Nov. 13, 2020) (remanded from Samsung Elecs. Co., Ltd. v. InfoBridge Pte. Ltd., 929 F.3d 1363, 1372 (Fed. Cir. 2019)); Acceleration Bay, LLC v. Activision Blizzard Inc., 908 F.3d 765, 773 (Fed. Cir. 2018); Blue Calypso, LLC v. Groupon, Inc., 815 F.3d 1331, 1348-49 (Fed. Cir. 2016); Open Text SA v. Box, Inc., No. 3:13-cv-04910, 2015 WL 4940798 at *7 (N.D. Cal. Aug. 19, 2015); CNET Networks, Inc. v. Etilize, Inc., 584 F. Supp. 2d 1260, 1274 (N.D. Cal. 2008).

[30] E.g., VidStream LLC v. Twitter, Inc., 981 F.3d 1060, 1066-67 (Fed. Cir. 2020); Hulu, LLC v. Sound View Innovations, LLC, Case IPR2018-01039, Paper 29 at *17-21 (PTAB, Dec. 20, 2019) (precedential); Ericsson Inc. v. Intellectual Ventures I LLC, IPR2014-00527, Paper 41 (PTAB, May 18, 2015); Kyocera Wireless Corp. v. Int’l Trade Comm’n, 545 F.3d 1340, 1351 (Fed. Cir. 2008).

[31] Valve Corp. v. Ironburg Inventions Ltd., Nos. 2020-1315, 2020-1316, and 2020-1379, Slip Op. at *16  (Fed. Cir., Aug. 17, 2021); James L. Quarles III and Richard A. Crudo, “[Way]Back to the Future: Using the Wayback Machine in Patent Litigation,” ABA Landslide, Vol. 6, No. 3 (Jan./Feb. 2014); see also Internet Archive, “Frequently Asked Questions”; Archive.Today at <>.

[32] See, e.g., Medtronic, 891 F.3d at 1379-83; Initiative for Medics., Access & Knowledge (I-MAK), Inc. v. Gilead Pharmasset LLC, IPR2018-00123, Paper 7 at *8-11 (PTAB, June 13, 2018); In re Klopfenstein, 380 F.3d at 1347-50; Ecolochem, Inc. v. S. Cal. Edison Co., 227 F.3d 1361, 1369-70 (Fed. Cir. 2000).

[33] See, generally, Jackie Unger, “Maintaining the Privilege: A Refresher on Important Aspects of the Attorney-Client Privilege,” Business Law Today (Oct. 2013).

[34] E.g., Lindley v. Life Inv’rs Ins. Co. of Am., 267 F.R.D. 382, 389 (N.D. Okla. 2010), aff’d in part as modified, No. 08-CV-0379-CVE-PJC, 2010 WL 1741407 (N.D. Okla., Apr. 28, 2010).

[35] See F.R. Civ. P. 26(b)(5); see also, e.g., Travis S. Hunter and Sara M. Metzler, “Is It Privileged? A Young Lawyer’s Guide to Preparing a Privilege Log in Commercial Litigation,” ABA Practice Points (June 29, 2018); Michael Downey and Paige Tungate, “Practical Advice on Privilege Logs,” Law Practice Today (Sept. 14, 2018). 

[36] E.g., Baxter Int’l, Inc. v. Becton, Dickinson and Co., No. 17-C-7576 (N.D. Ill, July 26, 2019); BASF Catalysts LLC v Aristo, Inc., No. 2:07-cv-222, 2009 WL 187808 (N.D. Ind., Jan. 23, 2009); Adobe Inc. v. RAH Color Techs. LLC, Nos. IPR2019-00627, -00628, -00629, -00646, Paper 59 (PTAB, Dec. 12, 2019).

[37] F.R. Civ. P. 26(b)(3)(A)

[38] E.g., Sioux Steel Co. v. Prairie Land Millwright Servs., Inc., No. 1:16-cv-02212 (N.D. Ill., May 19, 2021) (factual information in technical drawings related to attempts to design around patent discoverable, but counsel’s mental impressions and opinions about those efforts and legal advice sought or received not discoverable); In re Google Inc., 462 F. App’x 975, 976-79 (Fed. Cir. 2012) (nonprecedential) (email captioned “Attorney Work Product” expressing need for license was a technical/business investigation not protected work product, nor attorney-client privileged); Takeda Chem. Inds., Ltd. v. Alphapharm Pty., Ltd., No. 04-cv-1966, 2005 WL 1678001 (S.D.N.Y., July 19, 2005) (routine patent searches in ordinary course of business, irrespective of litigation, not protected work product).

[39] F.R. Civ. P. 26(b)(3)(A)

[40] 37 C.F.R. § 1.56; see also MPEP Chapter 2000.

[41] Therasense, Inc. v. Becton, Dickinson & Co., 649 F.3d 1276 (Fed. Cir. 2011 (en banc); see also, e.g., GS Cleantech Corp. v. Adkins Energy LLC, 951 F.3d 1310, 1328-32 (Fed. Cir. 2020).

[42] See Avid Identification Sys. Inc. v. Crystal Import Corp. SA, 603 F.3d 967, 974 (Fed. Cir. 2010).

[43] See USPTO, “Major Differences Between IPR, PGR, and CBM”.

[44] SAS Institute, Inc. v. Iancu, 584 U.S. ___, 138 S.Ct. 1348 (2018).

[45] 35 U.S.C. §§ 315(e) and 325(e); see also Wi-LAN Inc. v. LG Elecs. Inc., 421 F. Supp. 3d 911, 923-24 (S.D. Cal. 2019).

[46] Wasica Finance GmbH v. Schrader Int’l, 432 F. Supp. 3d 448, 453 (D. Del. 2020); IBM Corp. v. Intellectual Ventures II LLC, No. IPR2014-01465, Paper 32 at 5 (PTAB, Nov. 6, 2015).

[47] Valve Corp. v. Ironburg Inventions Ltd., IPR2017-00137, Paper 43 (PTAB, Jan. 25, 2018).

[48] E.g., The California Inst. of Tech. v. Broadcom Ltd., No. 2:16-cv-03714, Slip. Op. at *7-10 (C.D. Cal., Aug. 9, 2019); Wasica, 432 F. Supp. 3d at 452-55; Star Envirotech, Inc. v. Redline Detection, LLC, No. 8:12-cv-01861, 2015 WL 4744394, at *4 (C.D. Cal. Jan. 29, 2015).

[49] In re Freeman, 30 F.3d 1459 (Fed. Cir. 1994).

[50] Am. Hoist & Derrick Co. v. Sowa & Sons, Inc., 725 F.2d 1350, 1360 (Fed. Cir. 1984); accord Microsoft Corp. v. i4i Ltd. P’ship, 564 U.S. 91, 110 (2011); see also Ingersoll-Rand Co. v. Brunner & Lay, Inc., 474 F.2d 491, 496 (5th Cir. 1973).

[51] Campbell Soup Co. v. Gamon Plus, Inc., 939 F.3d 1335, 1340-41 (Fed. Cir. 2019); High Point Design LLC v. Buyers Direct, Inc., 730 F.3d 1301, 1313 (Fed. Cir. 2013); Durling v. Spectrum Furniture Co., 101 F.3d 100, 103 (Fed. Cir. 1996); contrast KSR Int’l Co. v. Teleflex Inc., 550 U.S. 398, 415-18 (2007).

[52] Egyptian Goddess, Inc. v. Swisa, Inc., 543 F.3d 665, 678 (Fed. Cir. 2008) (en banc); see also, e.g., Wallace v. Ideavillage Prods. Corp., No. 2015-107, 2016 WL 850860 (Fed. Cir., March 3, 2016) (nonprecedential).

[53] Egyptian Goddess, 543 F.3d at 678.