Prosecution History Estoppel in Design Patents
- Prosecution history estoppel can limit the scope of U.S. utility patent claims, usually through:
- Claim amendments
- Statements made during prosecution with the USPTO
- Less common: Estoppel affecting U.S. design patent claims.
- The Federal Circuit case Advantek Marketing, Inc. v. Shanghai Walk-Long Tools Co. illustrates this scenario.
Case Background
- Patent involved: U.S. Design Patent No. D715,006 (D’006 patent)
- During prosecution, USPTO required election between two embodiments:
- Portable animal kennel without a cover (elected)
- Portable animal kennel with a cover (not elected)
District Court Decision
- Advantek sued Walk-Long in the Central District of California.
- District court ruling:
- Prosecution history estoppel barred infringement, because Walk-Long’s kennel had a cover.
- Advantek’s arguments rejected:
- That Walk-Long’s kennel fell within the “skeletal structure design”
- That the election broadened, rather than narrowed, claim scope
- Relied on Pacific Coast Marine Windshields v. Malibu Boats (2014), which outlined three factors for estoppel in design patents:
- Whether there was a surrender
- Whether surrender was for patentability reasons
- Whether accused design falls within the surrendered scope
Federal Circuit Decision
- The Federal Circuit reversed the district court.
- Held that even if a surrender occurred, Walk-Long’s product was outside the scope of any possible surrender.
- Competitors infringe the D’006 patent if they use the patented structural design, regardless of additional features like a cover.
Key Takeaways
- Highlights post-issuance consequences of elections during design patent prosecution.
- Serves as a reminder to consider filing divisional applications to cover unelected embodiments.
- Confirms that additional features on a product do not necessarily avoid infringement if the core patented design is used.
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