Think Your Patent Covers More Than It Does? Your Own Words Might Say Otherwise

Written by Bob Fish, Fish IP Law. 06/04/2026

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If you’re an inventor or a startup founder thinking about filing a patent, here’s a hard truth: What you say during the patent process can quietly shrink your protection... even years later. The U.S. Court of Appeals for the Federal Circuit recently underscored this reality in the case of Puradigm, LLC v. DBG Group Investments, LLC. This decision serves as a masterclass in the "hidden traps" of patent prosecution and how a few sentences in a legal brief can dismantle a multimillion-dollar enforcement strategy.

“If I Could Turn Back Time” and some parody lyrics

The Simple Version: A Patent Lost Its Reach

The patent in this case involved an air purification system that utilized UV light and reflectors to neutralize contaminants. The alleged "secret sauce" was the use of specular (mirror-like) reflectors to direct UV light more precisely than previous designs.

When Puradigm sued a competitor, they hit a wall. The competitor used unpolished (non-mirror) aluminum reflectors. While the patent’s formal "claims" appeared broad enough to potentially cover various types of reflectors, the court ruled against the patent owner.

The reason? A statement made by the inventor's legal team years earlier during the application process.

The Hidden Trap: Prosecution History Estoppel

When applying for a patent, inventors (through their attorneys) engage in a back-and-forth negotiation with the USPTO known as patent prosecution. To get a patent approved, applicants often argue:

 "Our invention is different from prior technology because it uses X instead of Y..."

 "The prior art (existing technology) does not include the specific feature we have developed..."

These arguments are meant to persuade the examiner. However, under the legal doctrine of Prosecution History Estoppel, these arguments become part of the "public record." In the Puradigm case, the applicant argued that earlier technology lacked the mirror-like reflectors their invention required.

Even though the patent examiner actually disagreed with that argument at the time, the applicant never formally withdrew or corrected the statement.

"But the Examiner Disagreed!" — Why That Didn’t Matter

You might think, "If the Patent Office didn't buy the argument, why should it count against me later?"

The Federal Circuit’s answer is rooted in Public Notice. The court reasoned that competitors and the public are allowed to rely on what you said your invention was—and what you said it wasn't. If you tell the government your invention requires "mirror-like reflectors" to be unique, you cannot later claim in court that unpolished aluminum is "close enough."

 The Ruling: A rejected argument can still come back to haunt you. If you don't clearly retract a narrowing statement, it remains a permanent boundary around your intellectual property.

How This Affects Inventors and Startups

This isn't just a legal technicality; it has massive implications for company valuation and competitive advantage.

 1. Ghost Limitations: Your patent may look broad on paper, but the "file wrapper" (the history of your application) may have quietly gutted its power.

 2. Design-Around Blueprints: Competitors don't just read your claims; they read your prosecution history to find the "holes" you accidentally dug for yourself.

 3. Valuation Risks: During due diligence, sophisticated investors or buyers will look for these statements. If your patent is narrower than you claimed, your company's valuation could plummet.

 4. The "Silence" Factor: In this case, the applicant tried to hedge by stating they "neither agree nor disagree" with the examiner’s characterization. The court found this insufficient. Silence is not a retraction.

What Should Inventors Do Differently?

To protect your "Right to Exclude," you and your counsel must play the long game.

 1.Avoid Over-Explaining:** While it's tempting to throw every argument at the wall to get a patent granted, narrow arguments can win the battle (getting the patent) but lose the war (enforcement).

 2.The "Retraction" Protocol:** If an examiner misinterprets your invention or if you make an argument that is later deemed unnecessary, explicitly clarify the record.

 3.Think Like a Litigator:** Patent strategy shouldn't just be about getting a "ribbon" from the USPTO; it’s about ensuring that patent can survive a challenge in front of a judge.

 4.Consistency is Key:** Ensure that your technical descriptions in the specification align perfectly with the arguments made by your attorney during prosecution.

The Big Takeaway: Your Patent Is More Than the Claims

Most inventors believe the "Claims" section is the beginning and end of their protection. This case proves otherwise. Your patent is a living history of every word, argument, and concession made to the government.

Getting a patent isn't just about describing what your invention is. It’s about being incredibly disciplined regarding what you say it is not.

Sources:

 Puradigm, LLC v. DBG Group Investments, LLC*, No. 2023-1045 (Fed. Cir. 2024).

 * United States Patent and Trademark Office (USPTO) - Manual of Patent Examining Procedure (MPEP) § 2145.

 * Court of Appeals for the Federal Circuit (CAFC) - Recent Opinions Archive.

 Who is Bob Fish?

Bob Fish is the founder of Fish IP Law™, a premier intellectual property firm based in California. With over 30 years of experience, Bob is a veteran patent attorney known for his "Business-First" approach to IP. He has managed thousands of patent applications and is the author of several books on patent strategy, including Strategic Patenting. He specializes in helping inventors and companies transform their innovations into scalable, defensible business assets.

For more information, visit: www.fishiplaw.com