One way to increase the value of a design patent is to avoid making arguments during prosecution that disclaim, or narrow, the enforceable scope of the claim. This point was highlighted in a recent case from the Federal Circuit, Top Brand v. Cozy Comfort, 2025 U.S. App. LEXIS 17670 (Fed. Cir. 2025), where the Court held that prosecution history disclaimer applied because the applicant had clearly and unmistakably limited its claim by emphasizing specific design features as dispositive during prosecution. Since some arguments distinguishing prior art may trigger prosecution history disclaimer or estoppel, while others may not, careful word choice when responding to rejections is one of the most important strategic decisions a design patent prosecutor will make. But is it possible to predict in advance whether a particular argument will lead to disclaimer or estoppel? And how can such outcomes be avoided? A careful analysis of three cases may help provide some answers.
Key Takeaway Points
When responding to design patent prosecution rejections under 35 U.S.C. § 102 (anticipation) and 35 U.S.C. § 103 (obviousness), and distinguishing prior art, try to avoid triggering prosecution history disclaimer or estoppel by focusing your arguments on the overall visual impression of the claimed design. Arguments that overemphasize specific elements, especially with definitive language and annotated figures, risk being construed as a narrowing of claim scope. To minimize this risk:
- Consider framing your arguments on the designs as a whole. Emphasize how the totality of visual elements combine to create a distinct overall appearance.
- Consider using individual features as illustrative examples only. If you must reference specific differences, make clear they are not essential but merely support the broader ornamental distinction.
- Consider avoiding absolute language. Phrases like “for this alone, the design is patentable” or “this feature is significantly different” may suggest that a particular element defines the claim.
- Consider de-emphasizing annotated drawings. While visual aids certainly can help, making them the focal point of a specific feature-by-feature comparison rather than an overall visual impression risks overemphasizing the importance of individual design elements.
- Consider thinking ahead to litigation. If a feature is repeatedly and strongly emphasized in prosecution, it may be deemed disclaimed or surrendered later in court, even if it wasn’t strictly necessary to distinguish the prior art.
Carefully crafted arguments can preserve the full scope of the claim while still overcoming rejections. The goal is to persuade the examiner without limiting future enforcement options. The three cases discussed below show how differences in arguments can significantly impact the enforceability and litigation value of a design patent.
Case Summaries
In Top Brand v. Cozy Comfort, 2024-2191, 2025 U.S. App. LEXIS 17670 (Fed. Cir. 2025), the Federal Circuit applied prosecution history disclaimer to a design patent for an oversized hoodie with a front pocket (the difference between prosecution history disclaimer and prosecution history estoppel is explained in the comments below). During prosecution, Cozy Comfort distinguished its claimed design from prior art by emphasizing several specific features, such as the width and shape of the marsupial pocket, its position relative to the armholes, and the slope of the bottom hem. Full response here.
The court found that these detailed arguments constituted a clear and unmistakable disavowal of claim scope and construed the claim as not including these features. Since Top Brand’s accused products included the very features Cozy Comfort had disclaimed to obtain allowance, the court held that Cozy Comfort could not rely on those features to argue for infringement.
In Design Ideas, Ltd. v. Target Corp., No. 20-cv-3231, 2021 U.S. Dist. LEXIS 243072 (C.D. Ill. 2021), a district court rejected a defendant’s attempt to apply prosecution history estoppel to bar a finding of infringement. The design at issue was a wire mesh basket, and during prosecution of a parent application, the applicant distinguished prior art by listing nine features, including “seamless corners,” as reasons the claimed design created a different visual impression.
Defendant Target argued that this amounted to a surrender of all designs lacking seamless corners. But the court disagreed, emphasizing that argument-based estoppel requires a “clear and unmistakable” surrender, id. at *9, and that merely identifying multiple visual differences to overcome a prior art rejection does not amount to an explicit disavowal of any one feature. As a result, the court declined to apply prosecution history estoppel and allowed the infringement claim to proceed.
In Nike, Inc. v. Skechers U.S.A., Inc., No. LA CV17-08509, 2020 U.S. Dist. LEXIS 257711 (C.D. Cal October 26, 2020), a district court applied prosecution history estoppel to bar some of Nike’s design patent infringement claims. During inter partes review proceedings before the PTAB, Nike had repeatedly distinguished its asserted design patents from the prior art by emphasizing specific visual features, particularly “discrete arrays of converging and truncated lines of substantially the same width.” Id. at *19.
These arguments were made to oppose institution of review and were repeated across multiple filings and against several prior art references. The court found these statements to be clear and unmistakable assertions about the claimed design’s visual scope, made in support of patentability. Although Nike argued that it had relied on a variety of distinguishing features, the court held that estoppel is not limited to what was strictly necessary to overcome prior art.
Case Analysis
Top Brand v. Cozy Comfort
Why did the argument in Top Brand trigger prosecution history disclaimer? The applicant repeatedly focused on individual design elements (e.g., pocket position, pocket width, armhole placement, hem slope) and presented them as distinctive and dispositive. The phrase “[f]or this alone, the claimed design [was] allowable” was particularly damaging because it signaled to the examiner, and later, to a court, that certain features were essential to patentability. Using visual side-by-side annotated figures to call out these features on an individual basis, rather than collectively, added weight and specificity to the arguments. Finally, other than a conclusory statement, there was little effort to substantively argue that the overall combination of features created a different look. Instead, the applicant’s approach parsed the design into separable, isolated features.
Design Ideas, Ltd. v. Target Corp.
Why did the argument in Design Ideas not trigger prosecution history estoppel? The court found that the applicant’s statements during prosecution did not amount to a “clear and unmistakable” surrender of claim scope. Although the applicant distinguished prior art by listing nine visual features of the claimed wire mesh basket, including “seamless corners,” those features were not emphasized as essential or dispositive. Instead, the applicant argued that the overall visual impression of the claimed design differed from the prior art, and the listed features were offered collectively to support that point. The applicant did not single out any one feature as required for patentability. The court emphasized that argument-based estoppel requires far more than simply identifying visual distinctions. Since the applicant’s remarks were framed as only examples of differences contributing to the total appearance, the court declined to apply estoppel.
Nike, Inc. v. Skechers U.S.A., Inc.
Why did the argument in Nike v. Skechers trigger prosecution history estoppel? The court found that Nike repeatedly and unambiguously emphasized specific visual features as the basis for distinguishing its claimed designs from the prior art during inter partes review (IPR) proceedings before the PTAB. In particular, Nike relied heavily on the presence of “discrete arrays of converging and truncated lines of substantially the same width” as defining elements of the claimed designs. These statements were not isolated or incidental; they appeared across multiple Patent Owner Preliminary Responses (POPRs), were supported by annotated images, and were invoked in opposition to various prior art references. The court concluded that Nike had clearly and unmistakably surrendered claim scope encompassing designs lacking those particular line arrays.
Although Nike argued that it had relied on a variety of distinguishing features, the court applied argument-based estoppel and held that estoppel is not limited to what was strictly necessary to overcome prior art. Instead, estoppel may apply where a reasonable competitor would understand certain subject matter to have been surrendered based on the applicant’s repeated and specific representations. While this language may resemble prosecution history disclaimer doctrine, courts have used similar reasoning when evaluating argument-based estoppel, particularly where the patentee’s statements were clearly made in support of patentability and repeatedly emphasized particular features. Because Nike had consistently portrayed the converging and truncated line arrays as central to patentability, the court held that prosecution history estoppel applied, barring Nike from asserting infringement against designs that lacked those specific features.
How might the argument in Top Brand been improved?
Since in Top Brand the accused design appears to be closer to the prior art than to the patented design, avoiding prosecution history disclaimer ultimately may not have made a difference in the outcome of the case. However, to increase the chances of the case not being decided as a matter of law based on disclaimer, the following type of argument might be considered. This argument emphasizes overall appearance rather than individual elements, recasts specific differences as examples, not claim-defining features, and avoids definitive or absolute statements. This type of argument probably would at least make it harder for a court to find prosecution history disclaimer.
Claim 1 has been rejected under 35 U.S.C. § 102 in view of U.S. Patent No. D728,900 (“White”). Applicant respectfully submits that the overall visual impression of the claimed design is distinct from the reference and that an ordinary observer would not be deceived into purchasing one thinking it is the other. Accordingly, Applicant requests withdrawal of the rejection.
Although both designs generally reflect a hooded over-garment, the claimed design conveys a different and exaggerated ornamental impression, in part due to its overall proportions and styling. These differences arise from several aspects of the visual presentation, viewed in combination and in context.
For example, the claimed design includes a centrally positioned marsupial pocket that contributes to the overall look by visually dividing the elongated torso. In contrast, the reference places the pocket differently, integrated near the hemline, which alters the torso’s visual rhythm. The relative size and position of this pocket, along with its proportional relationship to the torso, supports a distinct ornamental appearance.
Other aspects that contribute to the differing visual impression include the relationship between the armhole openings and the pocket, as well as the configuration of the lower hem, which in the claimed design slopes in a different direction than in White. These characteristics, along with the overall exaggerated silhouette, produce a combination of visual effects that distinguish the claimed design in the eyes of an ordinary observer.
While certain features such as the hood and general structure are shared, these are common to many garments in this field and do not define the design’s overall visual impression. The claimed design’s collective arrangement and proportioning of familiar elements results in a distinct appearance, especially when considered in light of prior art.
Accordingly, Applicant respectfully requests that the § 102 rejection be withdrawn so that the application may proceed toward allowance.
Conclusion
Prosecution history disclaimer and estoppel are distinct but overlapping doctrines. Disclaimer narrows the claim during construction and limits literal scope. Estoppel applies during infringement analysis and bars the use of equivalence to recapture surrendered ground. Understanding the procedural and substantive differences is essential not just for litigators, but also for prosecutors who hope to secure broad but enforceable design patent rights. The key to avoiding both is prosecution focused on overall appearance, not piecemeal features. As courts continue to apply these doctrines to design patents, clarity and care in the record are more important than ever.
Comments and Notes
1. Shift from Estoppel to Disclaimer
In Top Brand, the Federal Circuit departed from the more commonly invoked doctrine of prosecution history estoppel by instead grounding its noninfringement holding in prosecution history disclaimer. Although estoppel traditionally has served as the primary mechanism for limiting claim scope based on amendments, elections, or arguments made during prosecution of design patents, Top Brand treated the applicant’s statements as a clear and unmistakable disavowal, invoking disclaimer as a matter of claim construction. This refinement in doctrinal focus warrants careful attention, as it highlights a meaningful distinction in the way courts may limit the scope of design patent claims.
2. Distinction between Disclaimer and Estoppel
Prosecution history disclaimer is a rule of claim construction. It limits the literal scope of the claim based on clear and unmistakable statements made by the patentee during prosecution. This doctrine is grounded in principles of public notice and is not equitable in nature. If the applicant distinctly and clearly disavows certain subject matter to obtain allowance, courts will interpret the claim as excluding that subject matter. This protects the public’s reliance on definitive statements made during prosecution. In Egyptian Goddess v. Swisa, 543 F.3d 665, 680 (Fed. Cir. 2008) (en banc), the Federal Circuit recognized that a trial court can construe a design patent claim by assessing and describing the effect of any representations made during patent prosecution.
Prosecution history estoppel, by contrast, is an equitable doctrine. It prevents a patentee from recapturing through the doctrine of equivalents that which was surrendered to obtain the patent. In utility patent law, the doctrine of equivalents is analyzed separately from literal infringement. However, in design patent law, both literal and equivalent infringement are determined under the unified Egyptian Goddess ordinary observer test: whether, in light of the prior art, the accused design is substantially the same as the claimed design in the eye of an ordinary observer.
In sum, both disclaimer and estoppel are trying to prevent patentees from asserting claims more broadly than what was justified in prosecution. But they function differently. Disclaimer narrows the literal claim. Estoppel limits what is equivalent to the claim.
3. Different Ways Prosecution History Estoppel May Arise
Prosecution history estoppel may arise in several different ways in design patent prosecution. In addition to estoppel by argument discussed above, it may result from a narrowing amendment made during prosecution in response to a rejection, such as amending a title. For example, in Curver Luxembourg, SARL v. Home Expressions Inc., 938 F.3d 1334 (Fed. Cir. 2019), the applicant changed the title from “Furniture (Part of‑)” to “Pattern for a Chair” in response to an examiner’s rejection that the original title was too vague to define a specific article of manufacture.
The Federal Circuit held this amendment constituted a narrowing of claim scope and gave rise to prosecution history estoppel, regardless of the lack of amendment to the drawings. The court ruled there was no infringement because the design was limited to patterns applied to chairs and not baskets, even though the accused baskets shared the same ornamental design pattern.
Estoppel also can arise if an applicant attempts to add to a drawing figure in response to a rejection and then has to remove the drawing addition due to a new matter rejection. In Australia Vision Services Pty., Ltd. v. Dioptics Medical Products, Inc., 29 F. Supp. 2d 1152 (C.D. Cal. 1998), the court applied prosecution history estoppel in a design patent case where the applicant submitted amended drawings to correct a rejection but was then required to remove newly added features after the examiner issued a new matter rejection under § 112. The applicant had introduced side panel lenses in revised drawings, which were rejected as impermissible new matter. To overcome the rejection, the applicant deleted the side lenses and the patent issued without them.
The court held that the sequence of adding and then withdrawing claim content to gain allowance constituted a surrender of claim scope. Because the accused sunglasses included the very side lenses that had been removed during prosecution, the court held that prosecution history estoppel barred the patentee from successfully asserting infringement.
Finally, as recognized in Pacific Coast Marine Windshields Ltd. v. Malibu Boats, LLC, 739 F.3d 694 (Fed. Cir. 2014), estoppel may result from a restriction requirement when the applicant elects one embodiment and fails to pursue the non-elected embodiments. In Pacific Coast, a case involving a boat windshield design, the patentee filed an application with various embodiments having different vent hole configurations.
The examiner determined that the drawings included five patentably distinct designs and required the patentee to select one group for prosecution. The patentee made the selection and ultimately continued prosecution of only two of the five design groups.
The patented windshield design sued upon contains a hatch with four circular vent holes. One of the design groups the patentee did not prosecute contains a hatch with two rectangular vent holes. The accused design contains a hatch with three trapezoidal vent holes.
The district court concluded that by failing to separately prosecute the cancelled embodiment, the patentee put the public on notice that the subject matter was surrendered and dedicated to the public. Although the abandoned design had two rectangular holes and the accused design had three trapezoidal vent holes, the district court found the accused design within the territory between the original claim and the amended claim and held the patentee estopped from claiming infringement. The Federal Circuit reversed, reasoning that although the applicant surrendered the claimed design with two holes on the windshield corner post, the applicant neither submitted nor surrendered any three-hole design.
Note that even though an election following restriction is not technically an amendment, the court held that such a choice in response to a patentability requirement effects a surrender of claim scope analogous to an amendment, and estoppel applies accordingly.
Importantly, the Federal Circuit has not applied “election type” prosecution history estoppel when a restriction requirement is issued between combination and subcombination claims, and only the subcombination claim issues as a patent and is enforced in litigation. See Advantek Marketing, Inc. v. Shanghai Walk-Long Tools Co., 898 F.3d 1210 (Fed. Cir. 2018). In Advantek, the examiner issued a restriction requirement between a frame design with a cover and a frame design without a cover. The applicant elected the frame design without a cover.
The defendant, who was selling an accused frame design with a cover, argued that prosecution history estoppel applied because the applicant did not pursue the frame with a cover. The district court found estoppel based on an election of species, but the Federal Circuit reversed, concluding that even if there had been a surrender, the accused product fell outside the scope of the purported surrender. The Court reasoned that Advantek elected to patent the ornamental design for a kennel with a particular skeletal structure and a competitor who sells a kennel embodying the patented design infringes, regardless of extra features like a cover that might be added to the design.
4. Differences in the Standards
Disclaimer requires a clear and unmistakable disavowal of claim scope. Courts are reluctant to apply disclaimer unless the prosecution record is unambiguous. Estoppel, however, applies where the surrender was made for reasons of patentability and the accused design falls within the scope of the surrender. The three-part test from Pacific Coast Marine asks: (1) was there a surrender; (2) was it made for reasons of patentability; and (3) does the accused design fall within the scope of that surrender?
Importantly, prosecution history disclaimer does not require that the statement be made for reasons of patentability. A statement made to distinguish the invention from the prior art, even if not strictly required, can trigger disclaimer. That’s because disclaimer is about public notice, what the patentee told the public the claim does not cover. Estoppel, being equitable, is more concerned with fair play: did the patentee narrow the claim to get the patent, and is it fair to now try to recapture that scope?
5. Differences in Responding to a Section 102 Rejection and a Section 103 Rejection
Note that Top Brand (where prosecution history disclaimer was found) involved a Section 102 anticipation rejection and Design Ideas (where prosecution history estoppel was not found) involved a Section 103 obviousness rejection. One of the important takeaways for prosecutors is the increased danger of prosecution history disclaimer when responding to anticipation rejections under § 102. This is due to several reasons. First, an anticipation rejection typically will involve prior art that is very close in appearance to the claimed design. Second, the prior art will consist of a single reference so the comparison will be one to one. Third, the anticipation standard closely mirrors the ordinary observer test used to assess design patent infringement. These three factors create an increased risk that whatever distinctions the applicant emphasizes to overcome the prior art may later be construed as implicit limitations on the claim during litigation.
In contrast, responding to obviousness rejections under § 103 may pose a lower risk of triggering disclaimer, since the analysis typically involves combining multiple prior art references that are not as close in appearance to the claimed design and applying a different standard than the ordinary observer test. Nonetheless, applicants must still be cautious not to characterize their design in limiting terms that may later be construed as disclaimers of claim scope.
6. Potential Confusion Caused by Reference to Pacific Coast Marine Windshields
In Top Brand, the Federal Circuit cited Pacific Coast Marine Windshields as a basis to apply prosecution history disclaimer to design patents. The Court stated “[w]e see no reason to distinguish between disclaimer by amendment and disclaimer by argument and conclude that a patentee may surrender claim scope of a design patent by its representations to the Patent Office during prosecution.” Id. at *9. However, Pacific Coast was not a prosecution history disclaimer case. Rather, it was the Federal Circuit’s foundational design patent decision applying prosecution history estoppel. In Pacific Coast, the court evaluated whether the patentee had surrendered claim scope through elections in response to a restriction requirement, applying the traditional three-part estoppel framework derived from Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co., 535 U.S. 722, 740 (2002). By importing Pacific Coast into a disclaimer analysis without distinguishing its equitable context, the Top Brand opinion risks conflating the two doctrines. This blending may obscure the distinct procedural timing, evidentiary burdens, and legal consequences that separate disclaimer, a rule of claim construction grounded in public notice, from estoppel, which serves as an equitable bar to recapturing subject matter surrendered during prosecution.
7. Practical Differences in Litigation
Prosecution history disclaimer is applied during claim construction. It is a matter of law for the court to decide, typically in a Markman hearing. Because design patents are usually construed by referring to the figures without verbal elaboration, a finding of disclaimer may substitute for or accompany claim construction. Importantly, if a court construes the claim narrowly based on disclaimer, that limitation applies to both literal infringement and equivalents, because the reach of substantial sameness under the ordinary observer test cannot expand beyond what the claim covers.
Prosecution history estoppel, on the other hand, is generally considered during the infringement analysis and is typically a factual question resolved at summary judgment or trial. If the accused product is not identical to the claimed design but is alleged as substantially the same, the patentee may argue infringement exists under the ordinary observer test. Estoppel may preclude such an argument if there is surrender of subject matter by the patentee either by amendment or argument and the accused design falls within the scope of the surrender.
Procedurally, the doctrines differ in how and when they must be raised. Because prosecution history disclaimer is a rule of claim construction, it must be raised during the claim construction phase (typically at or before a Markman hearing). Failure to raise it at that stage may result in waiver. In contrast, prosecution history estoppel is typically raised during the infringement analysis. It can be presented at summary judgment or at trial. However, like other defenses, if estoppel is not raised in a Rule 50(a) motion for judgment as a matter of law, it may be deemed waived for purposes of post-trial motions or appeal. Courts are generally stricter about waiver when estoppel is raised late in litigation, especially if the factual record has not been developed to address it.
Disclaimer: This article is for general information purposes only and is not intended to be legal advice.
