The Federal Circuit Expands Disclaimer of Patent Scope During Prosecution

The Federal Circuit Court of Appeals’ recent decision in Focus Products Group International, LLC v. Kartri Sales Co., Inc., No. 2023-1446 (Fed. Cir. Sept. 30, 2025) reversed summary judgment of infringement on two patents and vacated on a third. The Court held the district court erred in both claim construction and application of its infringement analysis by failing to properly find the patent file history disavowed subject matter relied upon to find infringement. The disavowal was critical because the claim language broadly covered the product’s configuration found to be infringing by the district court.

Shower Curtain Ring Image

A patent’s claim scope can be narrowed only if the file history contains a “clean and unmistakable” disavowal that overcomes the heavy presumption that claim terms carry their full and ordinary meaning.  In practice, that standard has been difficult to meet even when applicant’s arguments overcame prior art and examiner rejections. The accused device in Focus Products was a shower curtain ring with a flat upper edge (shown here). The Federal Circuit relied on several statements by the examiner that the application’s claims covered different species—one for a ring with projections and another for a ring with a “flat upper edge.” The patentee elected to withdraw claims covering a ring with a flat upper edge without objecting to the examiner’s definition. And in the Notice of Allowance, the examiner again stated that a “flat upper edge” fell outside the scope of the applicant’s election and invited the applicant to challenge that designation.  

The case law on claim disavowal typically requires the applicant to disclaim subject matter that would otherwise fall within the claim and often admonishes cases finding disclaimer based on examiner statements accompanied only by the applicant’s silence. In Focus Products, the Court considered that the applicant cooperated with the examiner’s exclusion of rings with a flat upper edge and therefore made it clear that it accepted the exclusion.

Having consented to the examiner’s claim narrowing, the patentee could not later in litigation reclaim the coverage of a ring with the flat upper edge even though reading the claims in isolation under their ordinary meaning would cover such a configuration.

The significance of the Federal Circuit’s decision is two-fold. First, it confirms that a patent applicant’s disclaimer during prosecution can occur without the applicant’s explicit and absolute disavowal of claim scope, and can be based on the applicant’s failure to challenge the examiner’s findings and taking actions consistent with those findings.

Second, the holding signifies the Federal Circuit’s easing of the standard to find disclaimer, which in practice has typically been a difficult hurdle even when the file history included arguments distinguishing the prior art to gain allowance, which district courts’ often found not clear and unmistakable to therefore not warranting disclaimer of claim scope.

This article is available in the Jenner & Block Japan Newsletter. / この記事はJenner & Blockニュースレターに掲載されています。

© 2026 Jenner & Block LLP. Attorney Advertising. Jenner & Block LLP is an Illinois Limited Liability Partnership including professional corporations. This publication, presentation, or event is not intended to provide legal advice but to provide information on legal matters and/or firm news of interest to our clients and colleagues. Readers or attendees should seek specific legal advice before taking any action with respect to matters mentioned in this publication or at this event. The attorney responsible for this communication is Brent E. Kidwell, Jenner & Block LLP, 353 N. Clark Street, Chicago, IL 60654-3456. Prior results do not guarantee a similar outcome. Jenner & Block London LLP, an affiliate of Jenner & Block LLP, is a limited liability partnership established under the laws of the State of Delaware, USA and is authorised and regulated by the Solicitors Regulation Authority with SRA number 615729. Information regarding the data we collect and the rights you have over your data can be found in our Privacy Notice. For further inquiries, please contact dataprotection@jenner.com.

The Federal Circuit Expands Disclaimer of Patent Scope During Prosecution

The Federal Circuit Court of Appeals’ recent decision in Focus Products Group International, LLC v. Kartri Sales Co., Inc., No. 2023-1446 (Fed. Cir. Sept. 30, 2025) reversed summary judgment of infringement on two patents and vacated on a third. The Court held the district court erred in both claim construction and application of its infringement analysis by failing to properly find the patent file history disavowed subject matter relied upon to find infringement. The disavowal was critical because the claim language broadly covered the product’s configuration found to be infringing by the district court.

Shower Curtain Ring Image

A patent’s claim scope can be narrowed only if the file history contains a “clean and unmistakable” disavowal that overcomes the heavy presumption that claim terms carry their full and ordinary meaning.  In practice, that standard has been difficult to meet even when applicant’s arguments overcame prior art and examiner rejections. The accused device in Focus Products was a shower curtain ring with a flat upper edge (shown here). The Federal Circuit relied on several statements by the examiner that the application’s claims covered different species—one for a ring with projections and another for a ring with a “flat upper edge.” The patentee elected to withdraw claims covering a ring with a flat upper edge without objecting to the examiner’s definition. And in the Notice of Allowance, the examiner again stated that a “flat upper edge” fell outside the scope of the applicant’s election and invited the applicant to challenge that designation.  

The case law on claim disavowal typically requires the applicant to disclaim subject matter that would otherwise fall within the claim and often admonishes cases finding disclaimer based on examiner statements accompanied only by the applicant’s silence. In Focus Products, the Court considered that the applicant cooperated with the examiner’s exclusion of rings with a flat upper edge and therefore made it clear that it accepted the exclusion.

Having consented to the examiner’s claim narrowing, the patentee could not later in litigation reclaim the coverage of a ring with the flat upper edge even though reading the claims in isolation under their ordinary meaning would cover such a configuration.

The significance of the Federal Circuit’s decision is two-fold. First, it confirms that a patent applicant’s disclaimer during prosecution can occur without the applicant’s explicit and absolute disavowal of claim scope, and can be based on the applicant’s failure to challenge the examiner’s findings and taking actions consistent with those findings.

Second, the holding signifies the Federal Circuit’s easing of the standard to find disclaimer, which in practice has typically been a difficult hurdle even when the file history included arguments distinguishing the prior art to gain allowance, which district courts’ often found not clear and unmistakable to therefore not warranting disclaimer of claim scope.

This article is available in the Jenner & Block Japan Newsletter. / この記事はJenner & Blockニュースレターに掲載されています。

© 2026 Jenner & Block LLP. Attorney Advertising. Jenner & Block LLP is an Illinois Limited Liability Partnership including professional corporations. This publication, presentation, or event is not intended to provide legal advice but to provide information on legal matters and/or firm news of interest to our clients and colleagues. Readers or attendees should seek specific legal advice before taking any action with respect to matters mentioned in this publication or at this event. The attorney responsible for this communication is Brent E. Kidwell, Jenner & Block LLP, 353 N. Clark Street, Chicago, IL 60654-3456. Prior results do not guarantee a similar outcome. Jenner & Block London LLP, an affiliate of Jenner & Block LLP, is a limited liability partnership established under the laws of the State of Delaware, USA and is authorised and regulated by the Solicitors Regulation Authority with SRA number 615729. Information regarding the data we collect and the rights you have over your data can be found in our Privacy Notice. For further inquiries, please contact dataprotection@jenner.com.

News and Insights

Publications

"DC Circuit Undercuts Congress's Subpoena Power: Important New Authority for Targets of Congressional Investigations," National Law Journal

In the National Law Journal, Congressional Investigations Co-Chair Emily Loeb, Special Counsel David Manners-Weber, and Associate Kate Mather examine a recent DC Circuit decision that gives fresh weight to 2020 Supreme Court dicta on common-law privileges in congressional investigations.

July 30, 2026

Publications

Meghan Greenfield Discusses Top Environmental Policies to Watch in Law360

Partner Meghan Greenfield spoke to for an article highlighting the key environmental regulatory developments expected in the second half of 2026. Meghan discussed the legal reasoning the agency may rely on as it considers further rulemaking addressing greenhouse gas pollution, and hurdles the agency may face. 

July 22, 2026

Publications

Partner Meghan Greenfield Quoted in The Associated Press on Offshore Wind and National Security

Partner Meghan Greenfield spoke with The Associated Press for an article examining the Trump Administration's use of national security justifications to halt offshore wind development.

July 21, 2026

Podcasts

Partner Laurel Loomis Rimon Discusses Fintech Enforcement, Debanking, and Regulatory Risk on Fintech Layer Cake Podcast

Partner Laurel Loomis Rimon was featured on the Fintech Layer Cake podcast, where she discussed how fintech enforcement and prosecution actually work in practice, and what exposes fintechs and banks to regulatory risk.

July 15, 2026

Event

Partner Suedeen Kelly to Speak at ABA SEER's 34th Fall Conference

On Thursday, October 15, Partner Suedeen Kelly will speak on a panel at the American Bar Association's Section of Environment, Energy, and Resources (ABA SEER) 34th Fall Conference in Albuquerque, New Mexico.

October 15, 2026