Copyrights Patents Q&A Trade Secrets Trademarks

What Should I Do to Avoid Infringing Anyone Else’s IP When Releasing a New Product?

Here is a common scenario. Your business is planning to release a new product but wants to avoid infringing anyone else’s IP. What should you do? To avoid infringing anyone else’s IP, you should consider proactive clearance or freedom-to-operate (FTO) efforts, ideally before the new product is commercially launched.  Such efforts are not legally mandated but should be tailored to your businesses’ risk tolerance in light of the typical costs of patent, trademark, copyright, and trade secret litigation.  The scope of these efforts will depend upon the type of IP involved.  Specific efforts may also depend on where you are planning to release the product, geographically. The following discussion focuses on the USA.

General Tips

Consider implementing overarching policies and protocols to reduce IP infringement (or misappropriation) risks. Educate and supervise staff accordingly. Do not simply assume that employees will already understand or care about IP infringement and misappropriation risks.

Make reasonable efforts to avoid infringement, including proactive clearance/FTO efforts where appropriate. But accept, as a cost of doing business, that despite those efforts there will always remain some risk that a “troll” will make an IP infringement claim of dubious merit.  Failing to make reasonable efforts will just make it easier for others to target you with infringement claims that are expensive to defend.

When making goods or materials at the request of a customer (e.g., private label goods), be cautious of harsh and potentially predatory indemnity or warranty terms in purchase agreements. These can come into play if the customer is requesting infringement—either intentionally or merely negligently—while passing all infringement liability onto your business.  You might be agreeing to assume IP infringement risks that far exceed the commercial value of the contract. This is also a concern where infringement liability may depend on customer actions outside your control.

It is also recommended to obtain a business insurance policy with coverage for unintentional trademark and copyright infringement (e.g., “advertising injury” coverage without major exclusions or limiting definitions). However, patent infringement coverage is not found in typical general business policies and is uncommon (because its cost/benefit tradeoff is rarely attractive).


For patents, the most common type of patent infringement has essentially a strict liability character and infringement does not depend on whether you had actual knowledge of the other party’s patent(s). However, though knowledge and intent (willfulness) can impact damages. Also, indirect infringement—a category of certain types of infringement—may require knowledge of the patent and that your activities infringe.

Consider a pre-launch patent FTO study that initially involves a search for any potentially conflicting patents, followed by a legal analysis. Proactively performing a patent FTO study allows you to find potentially problematic patents before they find you. That makes possible certain risk reduction efforts, such as an opinion of counsel, a design around, seeking a license, etc.


For trademarks, infringement has essentially a strict liability character and infringement does not depend on whether you had actual knowledge of the other party’s trademark. Liability can arise if there is a likelihood of confusion, even in the absence of any actual confusion by consumers. Trademark infringement does not have to be willful to result in a damages award. Also, there is a presumption that a trademark owner can obtain an injunction against use of an infringing mark.

When adopting new branding, it is not unusual for a first-choice mark (and second-choice…) to be already taken by another business. Many marks are already taken by others, which limits the universe of marks freely available for your business’ use at the time of adoption. It may be preferable to select a different mark from the start than to later re-brand, because re-branding tends to become more burdensome, costly, and disheartening as time passes.

Consider a pre-launch trademark clearance that initially involves a search for any potentially conflicting trademarks, followed by a legal analysis. Such a search should encompass all the relevant jurisdictions (e.g., all countries where your brand or mark will be used). Registration is not required to have enforceable trademark rights in the U.S. So a clearance search should ideally assess possible unregistered marks too.


For copyrights, there must be unauthorized copying of protected expression. Though there can be risks from copying that happens through inattention or negligent conduct. Fair use limits the copyright owner’s exclusive rights, but fair use will not always apply (and usually won’t when simply making commercial use of a work rather than making critical commentary about the work). There are many misconceptions about copyright law. For instance, just because something is available on the Internet does not make it “fair game” for your business’ use—even if denoted as being “free” or “royalty free”.

Have an awareness of copyright infringement risks. Also be aware of the ways that employees might commit infringement. For instance, employees posting materials to online platforms under via company accounts can present copyright infringement risks. Consider ways to educate employees about copyright and supervise employee activities.

Perform copyright clearance for any materials that you did not wholly create yourself that you plan to use, and obtain written permission or a license or assignment of ownership. Retain records of written authorizations. And make sure that you adhere to the terms of any license. Also consider seeking an indemnity for any licensed materials, because you could be licensing materials that are themselves infringing.

Trade Secrets

For trade secrets, there must be misappropriation of secret materials. Though there can be risks from misappropriation that happens though inattention or negligent conduct. However, trade secret misappropriation will generally only arise if your business had received secret information from someone else. This could occur by hiring an employee who knows confidential information from a prior employer.

For trade secrets, review any non-disclosure agreements (NDAs) in place and consider clean room or other protocols if any confidential materials were or will be received by staff. 

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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 is Prosecution History Estoppel?

Prosecution history estoppel can arise when the patentee relinquishes subject matter during the prosecution of the patent—that is, during examination of a patent application at the U.S. Patent & Trademark Office (USPTO)—either by amendment or argument. A narrowing amendment made to satisfy any requirement for patentability (under 35 U.S.C. §§ 101-103, 112, 161, or 171) may give rise to an estoppel.  When it applies, prosecution history estoppel will prevent a patentee from relying on the Doctrine of Equivalents to establish infringement based on the particular equivalents surrendered. A given claim limitation might be given only its literal scope (as properly construed) but no more. This policy allows competitors to rely on prosecution history estoppel to ensure that their own devices/processes will not be found to infringe by equivalence

The Basic Rule

The Doctrine of Equivalents is an equitable doctrine created by courts long ago. It is premised on language’s inability to capture the essence of innovation, allowing some protection beyond the literal scope of a claim where the claimed invention and the accused product or process are equivalent.  Its purpose is to “temper unsparing logic” that “would place the inventor at the mercy of verbalism and would be subordinating substance to form” and it evolved in response to situations where accused infringers attempted to “practice a fraud on a patent” by introducing “minor variations to conceal and shelter the piracy.” However, there is a tension between such concerns and the need for patents to put the public on notice of what a patent does and does not cover.

Prosecution history estoppel is about interpreting patent claims by reference to the history that led to their grant. It limits the patentee’s ability to establish infringement by equivalence to help provide certainty to competitors about the enforceable scope of a U.S. patent. Accordingly, the Doctrine of Equivalents is not available where prosecution history shows the inventor was able to capture equivalent differences in words but chose narrower language. The patentee cannot later recapture what was previously surrendered under the guise of the Doctrine of Equivalents. Where the original patent application once embraced the purported equivalent but the patentee narrowed his claims to obtain the patent or to protect its validity, the patentee cannot assert that he or she lacked the words to describe the subject matter in question. 

Estoppel Can Arise Through Amendment or Argument

Prosecution history estoppel can arise two ways: (1) by making a narrowing amendment to the claim (amendment-based estoppel) or (2) by surrendering claim scope through argument to the patent examiner (argument-based estoppel). These two possibilities are discussed in turn.

How Amendment-Based Estoppel Can Arise

The first way that prosecution history estoppel can arise is by way of a narrowing amendment to a claim during prosecution. The question of what constitutes a narrowing amendment will depend on the context of a particular patent claim. But a classic example is adding words that narrow the limitations of a claim to avoid a prior art reference cited in a rejection in an office action. As another example, which is less intuitive, courts have said rewriting a dependent claim in independent form is an amendment adding a new claim limitation, which constitutes a narrowing amendment that may give rise to an estoppel. 

How Argument-Based Estoppel Can Arise

Argument-based estoppel arises when the prosecution history evinces a “clear and unmistakable” surrender of subject matter. Argument-based estoppel most often arises when the patentee tries to convince a patent examiner that the claims of an application recite something different from the prior art. For instance, a patentee may have argued that a claim term has a meaning that is narrow enough to avoid a disclosure or teaching in a cited prior art reference. In such a situation, the patentee will likely be estopped from later asserting that the Doctrine of Equivalents encompasses what was previously argued to be outside the scope of the claimed invention. Such arguments are treated like an acknowledgement that the patentee knew the meaning of the claim language and deliberately chose narrower language in order to obtain a patent.

Scope of the Estoppel

Though prosecution history estoppel can bar a patentee from challenging a wide range of alleged equivalents used by competitors, its reach requires examination of the particular subject matter surrendered. Even where prosecution history estoppel applies, the scope of the estoppel is not always absolute. These inquiries differ somewhat between amendment-based estoppel and argument-based estoppel.

Scope of Amendment-Based Estoppel

The scope of amendment-based estoppel depends on the claim language at issue and the reason for the amendment. For instance, where the reason for the amendment was not related to avoiding the prior art, it does not necessarily preclude infringement by equivalents of that element. But an amendment to clarify the recitation of the claimed invention to satisfy definiteness requirements for patentability would give rise to an estoppel, even though there was no prior art reference prompting the change. Also, cancellation of a claim can give rise to estoppel with regard to any claim(s) that remain (or are added). However, the reason for an amendment is often not clear from the prosecution history.

When no explanation for an amendment is provided, there is a rebuttable presumption that the Doctrine of Equivalents is not available at all.  When the purpose underlying a narrowing amendment cannot be determined—and hence the rationale for limiting the estoppel to surrender of only particular equivalents—it is presumed that the patentee surrendered all subject matter between the broader and the narrower language.  But that presumption of amendment-based estoppel can be overcome for a particular equivalent when (1) the equivalent in question was unforeseeable at the time of the application, (2) rationale underlying the amendment bears no more than a tangential relation to the equivalent in question, or (3) the patentee could not reasonably be expected to have described the insubstantial substitute in question. 

Scope of Argument-Based Estoppel

The scope of argument-based estoppel is based on the scope of particular arguments made during prosecution. Unlike amendment-based estoppel, there is no presumption-and-rebuttal approach. Rather, the question is how far argument-based estoppel applies in the first place, if at all. The question is whether there was a clear and unmistakable argument-based surrender of particular subject matter. Courts have said that simple arguments and explanations to the patent examiner do not surrender an entire field of equivalents. But any arguments can still surrender some equivalents, even if they do not surrender all possible equivalents. This is very context-dependent. The key to this inquiry is whether a competitor would reasonably believe that the patentee’s argument had surrendered the relevant subject matter.

However, courts have said that any clear assertions made during prosecution in support of patentability, whether or not those assertions were actually required to secure allowance of a claim, may still create an argument-based estoppel. Also, once an argument is made regarding a claim term that creates an estoppel, that estoppel will apply to that term in other claims in the patent too.

Prosecution Disclaimer

Prosecution disclaimer is a separate but related concept. Rather than relating to the availability of the Doctrine of Equivalents to establish infringement, prosecution disclaimer or disavowal can limit the proper construction of a claim’s literal scope. Thus, it may affect whether or not literal infringement is found—prior to any consideration of the Doctrine of Equivalents. For example, it can arise when a patentee makes arguments during prosecution about how the pending claims differ from the prior art. This is meant to prevent patentees from opportunistically taking different (and broader) positions in court when asserting infringement than when obtaining the patent in the first place. Statements made during the prosecution of family-related applications, even later-filed ones and foreign counterparts, may sometimes result in prosecution disclaimer as well.

Questions about prosecution disclaimer pertain to proper claim construction. Claim terms are presumed to carry their full and customary meaning unless the patentee unequivocally imparted a novel meaning to those terms either in the patent application itself (called acting as her own lexicographer) or expressly relinquished claim scope during prosecution. Just as with argument-based estoppel, prosecution disclaimers must be “clear and unmistakable” in order to limit claim scope. An ambiguous statement during prosecution will not limit a claim term’s ordinary meaning.

An important difference between prosecution disclaimer and prosecution history estoppel is when they are taken into account. Prosecution disclaimer is a matter of claim construction. That is something courts do as a first step in patent infringement analyses, without reference to the specific product or process accused of infringement. In contrast, the Doctrine of Equivalents is bound up with the subsequent comparison of the accused product or process to the asserted patent claims as properly construed. Prosecution history estoppel is a question of whether a patent owner is permitted to invoke the Doctrine of Equivalents in particular ways in the second part of infringement analysis, after claim construction. But if literal infringement is found—despite any prosecution disclaimer—there is no need to reach the Doctrine of Equivalents.

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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 Patent Infringement Are Possible?

At a most basic level, patent infringement in the U.S. involves making, using, selling, offering for sale, importing into the USA a patented invention without authorization. Although there are some additional grounds for infringement that may apply in some other circumstances. All grounds for infringement fall into two general categories: direct infringement and indirect infringement. These categories refer to who is being accused and whether they are directly responsible or instead indirectly or partly responsible. There are multiple types of infringement under each category. These include literal or Doctrine of Equivalents infringement, and, for indirect infringement, active inducement of infringement, contributory infringement, and certain activities related to components for export from the USA. Each of these provisions, set forth in § 271 of the U.S. patent laws, is taken up further below.

Direct Infringement

Direct patent infringement means that an accused party is directly responsible for infringement a patent. Direct infringement requires that each and every limitation (or element) of at least one claim of an asserted patent is met either literally or under the Doctrine of Equivalents. If a limitation of a given patent claim is not present in the accused product or process, either literally or equivalently, then that claim is not infringed.

The sorts of things that can constitute direct infringement include the following:

  • making (that is, manufacturing) the patented invention in the USA (35 U.S.C. § 271(a))
  • using the patented invention in the USA (35 U.S.C. § 271(a))
  • offering to sell the patented invention in the USA (35 U.S.C. § 271(a))
  • selling the patented invention in the USA (35 U.S.C. § 271(a))
  • importing the patented invention into the USA (35 U.S.C. § 271(a))
  • submitting a new drug application for U.S. regulatory approval (Hatch-Waxman Act; 35 U.S.C. § 271(e))
  • importing into the USA, or offering to sell, selling, or using within the USA, a product which is made outside the USA by a process patented in the USA, unless it is materially changed by subsequent processes or it becomes a trivial and nonessential component of another product (35 U.S.C. § 271(g))
  • Certain additional rights to exclude specific to plant patents (35 U.S.C. § 163)

There are two ways of finding infringement that differ in terms of how the accused product or process relates to the scope of the claim(s) of the asserted patent:

  • Literal Infringement
  • Infringement Under the Doctrine of Equivalents (also called infringement by equivalence)

Literal Infringement

Literal infringement means that the accused product or process falls within the scope of the asserted claim(s) as construed by a court. Under U.S. law, infringement analysis is a two-step process. It involves, first, construing the claims to ascertain their meaning to a person of ordinary skill in the art and to resolve any ambiguities or disputes over that meaning, and, second, comparing the accused product/process to the properly construed claim(s). Literal infringement is present when the accused infringer meets each and every limitation (or element) of an asserted patent claim exactly, as properly construed. Any deviation from a claim limitation (as properly construed) precludes a finding of literal infringement.

Infringement Under the Doctrine of Equivalents

Under the Doctrine of Equivalents, a product or process that does not literally infringe upon the express terms of a patent claim may nonetheless still be found to infringe if there is “equivalence” between the elements of the accused product or process and claimed elements of the patented invention. This type of infringement arises when the accused product or process is outside the literal scope of at least one limitation of an asserted claim, as properly construed. Patentees rely on the Doctrine of Equivalents under the second step of the infringement analysis, if at all, only if literal infringement cannot be established. Otherwise, the Doctrine of Equivalents can apply to the same set of activities as for literal infringement.

This is an equitable doctrine meant to “temper unsparing logic” that “would place the inventor at the mercy of verbalism and would be subordinating substance to form.” It evolved in response to situations where accused infringers attempted to “practice a fraud on a patent” by introducing “minor variations to conceal and shelter the piracy.” Of course, the doctrine is in tension with the policy requiring that claims put the public on notice of a patent’s scope. This is a reason the Doctrine of Equivalents is not meant to be routinely invoked and is not applied broadly. In other words, this type of infringement is a limited exception to the general rule that patent claims must reasonably put others on notice of the outermost boundaries of what constitutes infringement. Put another way, it allows a limited form of “central” claim enforcement in a regime of “peripheral” claiming.

The Doctrine of Equivalents is applied individual claim limitations rather than to the claimed invention as a whole. To find infringement, each claim limitation (or element) must be found either literally or equivalently in the elements of accused product/process. This is called the “all elements” rule. The question of equivalence is inapplicable if a claim limitation is totally missing from an accused device. The Doctrine of Equivalents cannot be used to re-draft claims and effectively eliminate limitations entirely. Though this inquiry always revolves around what differences can reasonably be considered equivalent. An undue expansion of a patent’s claim(s) is not permitted. After-arising technology can potentially be encompassed by the Doctrine of Equivalents (unlike for means-plus-function equivalents).

There are two approaches to assessing equivalents: the “insubstantial differences” test and the “function-way-result” test. The function-way-result test (also called the “triple identity” test) says that equivalence may be present for a given element if the accused product/process performs substantially the same function in substantially the same way with substantially the same result. This is not the only way to assess whether differences are insubstantial, but it is particularly useful for certain types of inventions such as mechanical devices. For biochemical inventions, however, looking at substantial differences may sometimes be more appropriate than the function-way-results test.

There are numerous limits on the Doctrine of Equivalents, which are really beyond this basic introduction. But an extremely important limit on the availability of the Doctrine of Equivalents is prosecution history estoppel. Things that the patentee did or said when obtaining the asserted patent might limit the patentee’s ability to later rely on the Doctrine of Equivalents. So the Doctrine of Equivalents is not always or automatically available.

Indirect Infringement

Indirect patent infringement means that an accused party is causing or enabling someone else to infringe. It can apply when an accused infringer meets some but not all of the limitations (or elements) of an asserted patent claim. It includes three types of infringement, which differ in terms of what the accused indirect infringer is doing:

Generally speaking, there are additional requirements that must be satisfied to establish indirect infringement that are not required for direct infringement. Those additional requirements vary depending on what type of indirect infringement is asserted.

Also, relevant limitations of asserted claim(s) can be assessed under either their literal scope or under the Doctrine of Equivalents, if available—see discussions above of literal and Doctrine of Equivalents infringement for direct infringement. This is really to say that the Doctrine of Equivalents may still apply to indirect infringement scenarios.

Active Inducement of Infringement

Actively inducing someone else to infringe a patent constitutes inducement of infringement. Specifically, “[w]hoever actively induces infringement of a patent shall be liable as an infringer.” (35 U.S.C. § 271(b)). This is a form of vicarious liability. Active inducement requires taking an affirmative steps to encourage infringement by another entity, as well as knowledge that the encouraged acts infringe the asserted patent. A key component of inducement is that it requires there be at least one direct infringer. But the difference here is that instead of suing the direct infringer, a different entity is sued for inducement.

Inducement commonly arises in situations involving claims to a method of using a product. Rather than sue the end user, which may be a potential customer, the patentee instead sues a competitor making and selling products used by others to (directly) perform and infringe the asserted method claim(s). It also sometimes arises where a corporate officer or owner induces his or her company to infringe, making that individual personally liable for infringement.

Contributory Infringement

Contributory infringement arises when selling, offering to sell, or importing components that are specially made or adapted for use to infringe a patent. However, contributory infringement excludes activities involving a staple article or commodity of commerce that is suitable for substantial noninfringing use. A “substantial noninfringing use” is any use that is not unusual, far-fetched, illusory, impractical, occasional, aberrant, or experimental. So there is normally no liability for selling general-purpose commodities, even if they could be used in making or using a patented invention.

“(c) Whoever offers to sell or sells within the United States or imports into the United States a component of a patented machine, manufacture, combination or composition, or a material or apparatus for use in practicing a patented process, constituting a material part of the invention, knowing the same to be especially made or especially adapted for use in an infringement of such patent, and not a staple article or commodity of commerce suitable for substantial noninfringing use, shall be liable as a contributory infringer.”

35 U.S.C. § 271(c)

In order for contributory infringement to be present, the infringer must know that the combination for which his component was especially designed was both patented and infringing.  This knowledge requirement differentiates contributory infringement from direct infringement, which does not require any such knowledge of the patent or infringement (except to enhance damages).

Contributory infringement is important for situations involving the sale of repair or replacement parts for use in or with patented products or methods.

Supplying Component for Export for Combination Outside the USA

Section 271(f) of the patent laws creates two grounds for infringement involving activities in the USA relating to products made in a foreign country. They arise when components of a patented invention are supplied for export from the USA. These grounds for infringement are similar to yet distinct from active inducement and contributory infringement, discussed above. But these provisions do not require that the equivalent of “foreign” direct infringement occur. That is, the actual combination need not actual occur. However, these provisions apply exclusively to apparatus claims, and are not available for method/process claims. They also do not apply to activities that occur entirely outside the USA. Also, § 271(f)(1) has a quantitative requirement about the number of components involved and it does not apply to only a single component.


(1) Whoever without authority supplies or causes to be supplied in or from the United States all or a substantial portion of the components of a patented invention, where such components are uncombined in whole or in part, in such manner as to actively induce the combination of such components outside of the United States in a manner that would infringe the patent if such combination occurred within the United States, shall be liable as an infringer.

(2) Whoever without authority supplies or causes to be supplied in or from the United States any component of a patented invention that is especially made or especially adapted for use in the invention and not a staple article or commodity of commerce suitable for substantial noninfringing use, where such component is uncombined in whole or in part, knowing that such component is so made or adapted and intending that such component will be combined outside of the United States in a manner that would infringe the patent if such combination occurred within the United States, shall be liable as an infringer.”

35 U.S.C. § 271(f)

The grounds for infringement under § 271(f) are somewhat rarely invoked. This is largely because manufacturing costs are often higher in the USA than abroad. As a result, courts have not extensively clarified the scope and proper application of these provisions. But suffice it to say they may apply in situations where components are being produced and/or sold in the USA for export.

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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

When Should I Complete a Patent Invalidity Search?

There are many situations where it is desirable to challenge the validity or patentability of a granted patent or pending patent application. For instance, an invalidity search can be useful for an invalidity opinion to mitigate infringement liability, an invalidity defense in litigation, a proactive challenge to patentability at the U.S. Patent & Trademark Office (USPTO), or a pre-issuance submission (observations) to try to restrict or prevent a patent from being issued. But what is the best timing for such an invalidity search?

graphic of timeline for invalidity search

In one sense, an invalidity search is never strictly legally required. Though, practically speaking, invalidity searches are often crucial to avoiding or reducing liability for patent infringement in many contexts. These searches must be performed in a timely manner to obtain the greatest value from them. That includes performing searches in time to meet deadlines that require having suitable search results available.

Patent invalidity searches are reactive in the sense of being conducted in response to some infringement risk arising. That could be the receipt of a cease & desist letter, the filing of an infringement lawsuit against you, or other knowledge of a potentially problematic patent (e.g., via a freedom-to-operate study). In any event, an invalidity search requires first knowing which patent is the subject of the invalidity search. That is because an invalidity search depends on the scope of the particular claim(s) of concern and their effective filing date(s)—including any priority date(s).

It is a best practice to consider an invalidity search after a tangible risk of patent infringement comes to your attention. Knowledge of a patent coupled with a reasonable belief that infringement might be present can potentially give rise to enhanced damages for infringement. And knowledge of a pending patent application can potentially give rise to so-called “provisional rights” to pre-issuance infringement damages.

There may be deadlines that determine when invalidity search results are needed. For instance, in patent litigation in a district court, the court will issue a scheduling order that often sets a deadline to set for invalidity contentions. In is necessary to have search results available in order to formulate those invalidity contentions and prepare a suitable report. Other times, invalidity contentions might be requested through discovery requests, such as interrogatories. Either way, it is crucial to perform the invalidity search far enough in advance of such deadlines to allow for subsequent legal analysis of the search results.

Moreover, there are situations where a proactive challenge to a granted patent is desired. Proceedings such as inter partes review (IPR), post-grant review (PGR), oppositions, and the like may have various different deadlines by which a challenge must be filed. Such deadlines drive the timeline for completing invalidity searching. Just as in litigation, the search must be completed with time to spare to allow for legal analysis and preparation of any formal filing papers for the patent challenge, which may require considerable effort to prepare. Additionally, a pre-issuance submission (or observation) might be filed against a pending patent application and there likewise are both formal and practical deadlines to do so.

Lastly, if an opinion of counsel setting forth grounds for liability is desired to mitigate potential infringement damages, such an opinion should ideally be obtained before your relevant product (or process) is commercially launched. If patent in question is discovered only later, then such an opinion should be obtained without unreasonable delay. Having invalidity search results is a prerequisite to completing an invalidity opinion.

In all these possible settings, it is common for multiple invalidity searches to be performed. That can include follow-on invalidity searches performed in an iterative manner, in order to exhaustively locate prior art and to try to obtain sufficient prior art for desired (and reasonable) invalidity arguments as those arguments evolve and develop. It may also include searches performed by different searchers in different databases (including in non-patent literature databases), in different native languages, though investigation of prior public use and on-sale activities, and the like.

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

When Should I Complete a Patent FTO Search?

If you have decided to perform a freedom-to-operate (FTO) or “clearance” study to try to reduce the risk of patent infringement, it will be necessary to determine when a patent search should be performed. This is a question about best practices for the timing of patent FTO/clearance searches.

The following timeline provides an overview of major timing considerations and the best time to conduct a patent FTO study.

In general, the ideal time to conduct at FTO search is before a product (or technical process/service) is commercially launched but after its technical design parameters are sufficiently established to know what the search should encompass. That is a window of time in between an initial business case and the beginning of research & development (R&D) efforts, on the one hand, and the formal product launch on the other. Additionally, the FTO search and accompanying legal analysis should be completed well enough in advance of the product’s commercial launch date to allow time for possible risk mitigation efforts before infringement liability might start to arise. If the FTO search uncovers a potentially problematic patent, you gain the most benefit from that information if you have allowed time to take responsive action before a product launch point-of-no-return.

In this context, a product launch can be anything that is potentially actionable as patent infringement, including making, using, selling, offering for sale, or importing an infringing product in or into the USA. Though product launch infringement risks tend to be greatest when there is a major commercial release that makes the product (or process) widely publicly available, as opposed to mere preparatory efforts (such as prototyping) that might happen only on a private and confidential basis.

Having technical design parameters that are sufficiently established to know what the search is important. This allows the FTO searcher to understand what, specifically, should be searched—and what is excluded from the scope of the search. This process of determining what to search is referred to as “feature identification” (or sometimes “product decomposition”). This involves itemizing individual patent-sized technical features present in the product that are to be searched. But feature identification is only possible if there is sufficient technical information available. If R&D efforts are still in preliminary stages, or if there is really only a (non-technical) business case available, it may not be feasible to conduct an FTO search yet, or at least not for all planned product features. In those situations, a more generalized “landscape” search is perhaps more appropriate. Otherwise, the FTO search(es) for insufficiently-developed feature(s) may need to await further technical R&D.


After an FTO search is completed, there are various reasons why a later “update” search may be helpful. First of all, there is generally a delay of roughly eighteen (18) months between the filing and publication of most patent applications—and sometimes longer. This means that there may be relevant pending (but unpublished) patent applications that cannot be found during an initial FTO search. But, additionally, there may be changes to the technical design of planned or released product over time that merit further FTO searching and/or analysis. So, at what time(s) should such FTO search updates be performed? There are actually multiple possible approaches.

Discrete FTO Updates

A first approach is to perform one or more discrete FTO updates that resemble the initial FTO search and analysis. The timing of such discrete updates can be based on product- or technology-based milestones and/or calendar- or timeline-based milestones.

A typical product/technology milestone would be the release of a new or different version of a given product that has new, improved, or simply different features and functionality. An example would be releasing version 1.1 or 2.0 of a product that was previously cleared for its version 1.0 design only. Another typical product/technology milestone would be the occurrence of a particular pre-release design review phase. Technologies that have relatively long development cycles sometimes go through formalized design review processes with multiple distinct phases. In each phase changes to the product design might be introduced. For instance, a given initial product design might work well in prototype form but later be discovered to be too difficult to manufacture efficiently and thus might be replaced with a more easily manufactured design that was not previously searched.

An example of a calendar-based milestone would be to simply conduct a search update on a set periodic cycle, such as every year, or a single time after 18 months have passed since the original FTO search. There is no right or wrong update time period here, or even an particular appropriate number of updates. This is really a trade-off between the burden and expense of each update and the infringement risks likely raised, including the density of ongoing patenting on relevant technologies. Though recall that unpublished pending patent applications might first become available 18 months (or more) after the original FTO search.

Ongoing Monitoring

It is also possible to conduct ongoing monitoring of all patents and published applications for:

  • particular competitor(s)
  • particular technology area(s)

Ongoing monitoring can be facilitated through the use of alerts/saved criteria set up with proprietary search platforms or, alternatively, periodic (manual) searches. Such ongoing monitoring can take place in addition to or in place of other milestones or criteria for an FTO search. The main decision points with respect to ongoing monitoring are when to start and when to stop monitoring, and the scope regarding which competitor(s) and/or technology area(s) are included. Those factors are often highly influenced by the time and resource commitments required, as well as the relevance of those efforts to planned or ongoing commercial activities. It is worthwhile to periodically revisit the parameters for ongoing patent monitoring efforts, to ensure that those efforts are still relevant and appropriately focused.

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

When is an Opinion of Counsel Worthwhile?

Obtaining an opinion of counsel is a way to help defend yourself in a later patent infringement dispute. In the most general sense, opinions help demonstrate that you acted in good faith at the time. In court, an opinion can be used for an advice of counsel defense against charges of active inducement of infringement or willful infringement, and to rebut demands to pay the other side’s attorney fees because the case is “exceptional”. A finding that infringement was willful can lead to enhanced damages (up to 3x). And the patentee’s attorneys fees can be considerable. So an opinion can help limit exposure.

Opinions are not required. By statute, failure to obtain an opinion of counsel, or to rely on one at trial, cannot be used against the accused infringer to prove willfulness or inducement. It is up to an accused infringer to decide if the burden of obtaining an opinion is worthwhile or not. So the real question become: what circumstances make an opinion worthwhile? Below is a summary of some factors to consider when deciding if you should get an opinion. There are grouped into three categories, though the categories do overlap.

In the end, many of these factors are about whether your conduct might be seen (after-the-fact) as having been reckless and therefore unreasonably risky, with an opinion representing the best way to show that your intent was reasonable at the time. More generally, obtaining an opinion can be a key component of overall efforts to develop and implement strategically beneficial legal positions going forward.

Elevated Exposure Risk Factors

Certain circumstances present elevated exposure risks when it comes to patent infringement. In other words, some circumstances make a patent lawsuit more likely or more costly if you lose. These factors include:

  • You received a cease & desist or licensing letter from the patentee
  • The potential amount of (enhanced) damages is high, such as from high-volume sales
  • The potential amount of attorney’s fee award is high, such as if both sides are inclined to fight to the end rather than settle
  • There is a particularly high chance of a lawsuit; for instance:
    • the patent owner is a direct competitor in a highly competitive industry
    • the patent owner is litigious or has been suing many others in your industry for infringement
    • you have a history of disputes with the patent owner, even if not necessarily about patents
    • the patent owner sued you for infringement in another jurisdiction
    • the patent owner is a former vendor you broke ties with to make a similar product yourself
    • you hired away an inventor-employee from the patent owner to work on a competing product
    • you recently won over a customer, contract, or bid from the patentee
  • You believe there is a high probability the patentee will sue and seek a preliminary injunction

Factors Relating to Particular Defenses

Various patent infringement defenses depend on the accused infringer’s state of mind. But many legal questions surrounding patent infringement are complicated. A written opinion by competent legal counsel documents a defense so that it is clear later on that the investigation and legal analysis were sufficient to reasonably rely on. In other words, it makes clear that your defense was not conclusory, superficial, based on inaccurate information, biased, exaggerated, conjured up after-the-fact, or unreasonable. These factors include:

  • You want to completely avoid liability for inducement of infringement based on non-infringement (lack of scienter); this often applies when another entity such as a customer or end-user performs steps of a method claim using your product
  • You want to rely on an invalidity or unenforceability defense; it is almost never reasonable to rely on the invalidity or unenforceability of an asserted patent without an opinion of counsel because those defenses usually involve complex legal and factual issues, and because patents are presumed valid and overcoming that presumption carries a high burden of proof in court
  • Your non-infringement position relies on a particular claim interpretation (rather than the unambiguous and uncontroversial absence of a claim element under its plain and ordinary meaning); for instance:
    • non-infringement rests on the interpretation of a “means-plus-function” claim limitation
    • non-infringement relies upon a claim interpretation citing dictionaries, technical treatises, or other extrinsic evidence
    • you want to rely on something in the prosecution history to inform claim interpretation, such as a prosecution disclaimer or disavowal of claim scope
    • you believe the patent owner disclaimed or disavowed something in the patent or acted as his or her “own lexicographer” to define a claim term in a particular way
    • differences between products within the claimed technology area are extremely complex, nuanced, or counter-intuitive in general, making proper interpretation prone to error
    • the claims would be difficult for an ordinary juror to understand on their face
  • Your non-infringement position relies on complex indirect (contributory) infringement, extraterritoriality, or permissible repair issues; for instance, your position implicates the repair/reconstruction doctrine for non-staple-of-commerce goods, implicates manufacturing processes performed abroad on goods later imported, or implicates split or divided infringement issues for method/process claims
  • The doctrine of equivalents is a concern; that is, you want to rule out a plausible infringement theory under the doctrine of equivalents where there is no prosecution history estoppel, or you want to confirm that prosecution history estoppel applies to a crucial claim element

Business and Reputational Factors

Other relevant factors are less about the legal basis for defenses but instead have to do with business relationships, company policies, practicalities of technology, and marketplace considerations. These factors include:

  • An opinion can evaluate the effectiveness of a “design-around” that changed your planned product configuration to avoid infringement; in other words, the opinion is the culmination of more wide-ranging efforts to avoid infringement
  • You want to document your position so that you can better stick to it despite changes in company personnel, corporate mergers, etc.; this also includes documenting your position to avoid unwittingly undoing efforts to “design-around” a patent with subsequent product changes (possibly years later when the reasons for the design-around are nearly forgotten)
  • An opinion can help convey technical and legal issues to corporate leaders and decision-makers who lack a deep understanding of the technology or patent law
  • Having obtained an opinion of counsel can help provide comfort and a confidence boost to executives and employees who would likely be called to testify in an infringement lawsuit
  • You signed a contract that requires you to obtain an opinion of counsel
  • You offer an indemnity to a customer, distributor, etc. and want to limit exposure for those others’ activities (which may not be entirely within your control)
  • You want to tell customers, distributors, business partners, or investors that you obtained an opinion, in order to reassure them (while withholding the substantive opinion to preserve privilege)
  • Establishing a regular policy of obtaining opinions when aware of infringement risks as concrete evidence of a general good faith posture regarding competitor and other 3rd party patents; it may even be what you would expect others to do if your own patent was at issue
  • Obtaining an opinion can allow for risk mitigation without limiting action to the most conservative legal position; that is, an opinion can help legal counsel or a legal department devise an acceptable path forward and avoid a reputation for saying “no” to too many business proposals
  • You want to limit liability of individual corporate executives or directors in their personal capacity, including for inducing infringement by the corporation or in piercing the corporate veil scenarios

Parting Remarks About Opinions

Opinions of counsel may not be legally required but obtaining them is often still worthwhile. They can provide great evidence to present to a judge or jury in defense against infringement allegations. That is especially the case when relying on an invalidity argument or a particular claim interpretation. Having an opinion provides a fall-back position so that if you are found to infringe you (hopefully) don’t have to also pay punitive damages or the patentee’s attorney’s fees. A non-infringement opinion can also potentially avoid any and all liability for inducement of infringement (if applicable). But any opinion really needs to be in writing and be prepared by competent outside counsel in order to have the best chance of being effective in those respects. Seriously consider obtaining an opinion whenever a potentially problematic patent comes to your attention.

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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.


Copyright Pitfalls: Ways to Avoid Copyright Infringement and Ownership Disputes

A version of this article appeared in AIPLA’s Innovate Magazine in October 2021.

Mark Twain observed that “[o]nly one thing is impossible for God: to find any sense in any copyright law on the planet.”[i]  From the standpoint of individuals and small businesses, Twain’s observation might ring true.  Not only do some people have difficulty distinguishing between what they feel copyright law ought to entail and what it actually does entail, there are many genuinely ambiguous and confusing copyright issues that arise from everyday practices.  What follows is a collection of observations about a few common copyright infringement pitfalls, meant as a practical reference for those who wish to avoid finding themselves embroiled in an avoidable copyright dispute.

“Free” Materials

“Free” photo and clipart websites and similar archives are used at your own risk.  Unless provided with full indemnity, which usually is not provided, ordinary users are liable for infringement if the “free” image website did not actually have permission to use and distribute the image(s) in question.  Put another way, just because a web site claims to grant free use of images that appear on the site does not mean that the site operators actually have the authority to grant such permission for a given image—the site operator or whoever uploaded an image to the site might be an infringer.  In some instances, there may even be reason to suspect that the alleged owner is aware of the presence of materials in a “free” repository—or was even responsible for placing the materials there—and seeks settlements in bad faith or through outright fraud.[ii]  

Will an “innocent infringer” defense help in these situations?  Not against liability.   Though it potentially limits statutory damages.[iii]  How much it might limit statutory damages is discretionary, it may not limit actual damages,[iv] and it will not prevent an injunction.  In pragmatic terms, innocent infringement defenses do very little in the face of nuisance settlement demands from copyright owners engaged in troll-like enforcement activities. 

“Creative Commons” (CC) licenses are another area where materials turn out to be less usable than believed.  There are different types of CC licenses and a given work subject to one kind of CC license may not permit your intended use, especially if your use is “commercial” in nature.  And, as discussed below, removal of copyright management information (CMI) from CC works is still a potential source of liability.

Moreover, even where a copyright owner freely grants use of a particular image, if it is an image of a person or derivative of another work—like a photo of a sculpture, painting/mural, clothing design, etc.—then separate authorization or release of a right of publicity/privacy (a so-called model release) for the depicted person or copyright authorization for the depicted work may still be required.  Very likely any such additional authorization(s) must be sought from a different person or entity. 

Licensing Stock Images

Many stock image providers offer what seem like intentionally confusing licenses.  “Royalty free” images (and music) are not actually free but rather are usually subject to lump sum license payments—advertisements about the provider’s license terms may be confusing if not outright misleading.  Many stock image providers also offer different types of licenses that are difficult to differentiate.  For instance, the least expensive types of stock image licenses often do not cover use for “merchandising”, use on more than a specified number of hard copies, use with video production budgets over a certain threshold, etc.  Understanding which type of license addresses your particular intended use may not be simple.  Yet, if you purchase an incorrect license you may find yourself in the position of having made an unlicensed use. 

Lastly, stock image providers may not offer indemnity or, if they do, it might be provided at levels well below statutory damage maximums.[v]   Therefore, if you license an image only to later discover that the image provider was not authorized to license that image you could find yourself in a lawsuit with a monetary exposure that may exceed your apparent culpability.  

Outside Contractors and Ownership

You need a written assignment to own copyright in outside contractors’ work.  This holds even when an outside contractor was specifically hired to create copyrightable works, such as advertising copy, software code, photos, videos, etc.  While “works made for hire” are initially owned by the employer, absent a written agreement to the contrary,[vi] that ownership provision only applies when the work is created by an employee within the scope of his or her job duties or if there is a written work-made-for-hire agreement and the work falls within nine statutory categories of works (and, chances are, it probably does not fall in one of those categories).[vii]  In single-member LLCs and similar small businesses where the owner’s status as an “employee” may be in doubt under agency law, and there is no employment or other applicable agreement in place to clarify, then the ownership of copyrights created by such a person may be subject to dispute at some point. 

Outside vendors, like marketing companies, will sometimes have service agreements with their customers stating that the customer will own all of the work product, but such language may be phrased in the future tense, which is generally not sufficient to constitute an assignment of copyright—in such cases only a contractual obligation to assign has been established and an additional written assignment is required for the customer to actually obtain ownership of particular copyrights, though this may vary under state law.[viii] 

Failure to own a copyright prevents enforcement against infringers.  So, if a business hires an outside photographer to take photos for the business’ web site, if a competitor copies any of them the business may find that it does not own the copyrights in the photos and therefore cannot assert infringement until ownership is secured. 

DMCA Takedowns

The Digital Millennium Copyright Act (DMCA) includes a “safe harbor” notice-and-takedown provision in 17 U.S.C. § 512.[ix]  Takedowns can be powerful tools against online piracy but can also be abused or misused.  There are also known scams involving infringers of a copyright using takedown notices to seek nuisance settlements from third parties (who may be protected by fair use) and allegations of usage to silence critics

CMI, Circumvention, and Repair Issues

Liability for knowing removal or alteration of copyright management information (CMI) is set forth under 17 U.S.C. § 1202.  CMI includes the title, author or copyright owner names, and terms and conditions for use.  While the law requires removal to be knowing, rather than unwitting or unintentional, and further requires knowing or having reasonable grounds to know that doing so will induce, enable, facilitate, or conceal an infringement, copyright owners sometimes broadly assert CMI removal to seek additional damages or as a fallback position when substantive infringement claims are unavailable.[x] 

Section § 1201 limits “circumvention” of a technological measure that effectively controls access to a copyrighted work, unless the Library of Congress grants an exception.  Product/repair manuals, error code outputs generated by diagnostic tools, and/or diagnostic tools themselves may be subject to anti-circumvention restrictions stemming from copyright, which can impact the ability to repair a purchased item.  Aside from Section 1201 anti-circumvention exemptions, state right to repair law may provide some counterbalance.  

End user license agreements (EULAs) also bridge copyright law and contract law and attempt to circumvent the first sale doctrine (more generally, exhaustion of rights).  They may limit or prevent the use of unauthorized repair sources or transfer/resale, even if the enforceability of such EULA terms might be questioned in some jurisdictions. 

Predatory Contracts

Finally, buyers sometimes request products from vendors while specifying product requirements (e.g., a fabric pattern or decorative image, included text or video) for which the buyer may not have rights.  That is, the buyer may be requesting an infringing knock-off product without explicitly saying so—and possibly without realizing that copyright infringement is being requested.  All liability for copyright infringement may nonetheless be placed on the vendor by a purchase agreement, including a buyer indemnification that overrides the Uniform Commercial Code (UCC).[xi]  Such agreements might be called predatory contracts where they give the appearance of an opportunity for the vendor when, at bottom, they are really vendor liabilities and the buyer is shifting a greater risk to the vendor than the value of the contract. 

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.


[i] Mark Twain, Mark Twain’s Notebook (A.B. Paine, ed., 1935) quote reprinted at <>.

[ii] See also U.S. v. Hansmeier, No. 19-2386 (8th Cir., Feb. 10, 2021); Jason Mazzone, “Copyfraud,” 81 N.Y.U.L.R. 1026 (2006).

[iii] 17 U.S.C. § 504(c)(2).

[iv] Actual damages may be low or difficult to establish.  See, e.g., On Davis v. The Gap, Inc., 246 F.3d 152, 165 (2d Cir. 2001); Gregerson v. Vilana Fin., Inc., No. 0:06-cv-01164, 2008 U.S. Dist. LEXIS 11727, *14-15 (D. Minn., Feb. 15, 2008).

[v] General business insurance polices may cover non-willful copyright infringement, such as under “advertising injury” provisions. See, generally, David A Gauntlett, IP Attorney’s Handbook for Insurance Coverage in Intellectual Property Disputes (2nd ed., ABA 2014).

[vi] 17 U.S.C. § 201(b).

[vii] 17 U.S.C. § 101; see also Z. Peter Sawicki et al., “Copyright Ownership: A Mere Handshake Isn’t Good Enough” AIPLA Innovate (Sept. 24, 2018).

[viii] E.g., TD Bank N.A. v. Hill, 928 F.3d 259, 274 (3d Cir. 2019); cf. IpVenture, Inc. v. Prostar Computer, Inc., 503 F.3d 1324, 1327 (Fed. Cir. 2007) (interpreting “agree to assign” as requiring subsequent written instrument to effectuate assignment of patent rights).

[ix] See also U.S. Copyright Office, “Section 512 of Title 17: A Report of the Register of Copyrights” (May 2020).

[x] See, e.g., Philpot v. WOS, Inc., No. 1:18-cv-00339, 2019 WL 1767208 (W.D. Tex. April 22, 2019); Mango v. BuzzFeed, Inc., 970 F. 3d 167, 171 (2d Cir. 2020) (A plaintiff must prove the following: (1) the existence of CMI in connection with a copyrighted work; and (2) that a defendant distributed works or copies of works; (3) while knowing that CMI has been removed or altered without authority of the copyright owner or the law; and (4) while knowing, or having reasonable grounds to know that such distribution will induce, enable, facilitate, or conceal an infringement.); Stevens v. Corelogic, Inc., 899 F.3d 666, 673-75 (9th Cir. 2018) (there are two scienter requirements and for the second the copyright owner “must provide evidence from which one can infer that future infringement is likely, albeit not certain, to occur as a result of the removal or alteration of CMI” “such as by demonstrating a past ‘pattern of conduct’ or ‘modus operandi’, that the defendant was aware or had reasonable grounds to be aware of the probable future impact of its actions.”). 

[xi] UCC § 2-312(3) (2002) (“a buyer who furnishes specifications to the seller must hold the seller harmless against any such [infringement] claim which arises out of compliance with the specifications”).


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.