The Federal Circuit Extends the Doctrine of Prosecution History Estoppel to Design Patents

In a case of first impression, the U.S. Court of Appeals for the Federal Circuit held that the doctrine of prosecution history estoppel applies to claims of design patent infringement. However, the scope of its application may be more restricted than its application to utility patents.

In Pacific Coast Marine Windshields Ltd. v. Malibu Boats, LLC et al, No. 2013-1199 (Fed. Cir. Jan. 8, 2014), the patentee appealed a decision of summary judgment of non-infringement based on prosecution history estoppel. At issue were various ornamental designs for boat windshields. The original application depicted five distinct embodiments with differing configurations of vent holes and hatches in the windshield. During prosecution, the patentee overcame a restriction requirement by electing one of the five proposed designs (the patentee filed one divisional application for one of the other claimed designs but did not for the remaining surrendered designs). The district court found that the patentee surrendered the remaining claimed designs and that the accused design fell within the scope of the surrendered designs. As such, the patentee was estopped from claiming infringement based on the surrendered designs.

In reaching its holding of applying the doctrine of prosecution estoppel to design patents, the Federal Circuit analyzed the purpose of the doctrine as applied to utility patents. Prosecution estoppel prevents a patentee from claiming subject matter surrendered during prosecution of a patent. It limits what a patentee may claim as equivalent to their claimed invention. The Federal Circuit found that the same principle should apply equally to design patents. In fact, the doctrine arguably has more applicability to design patents given the statutory standard for design patent infringement (the “colorable imitation” standard) by its very nature typically “involves the concept of equivalents” and rarely involves identical copies of the claimed design.

Once the Court determined applicability of the doctrine, it further had to resolve whether one would be estopped based on an election of a particular embodiment in order to overcome a restriction requirement. For design patents, the Court considered whether such an election of embodiments and surrender of certain designs limits a patentee’s claims of equivalents in an infringement context. In particular, the restriction requirement as applied to design patents is not a mere administrative convenience, but rather is to comply with requirements that design patents only include a single claim. See e.g., MPEP § 1503.1. Thus, an election to overcome a restriction requirement is required to ensure patentability of a design patent (the Court left unresolved whether overcoming a restriction requirement would constitute estoppel for utility patents, which lack the same restriction of one claim per patent application).

In this case, the patentee surrendered two-hole designs and elected a four-hole and zero-hole design for its windshield design. But the accused windshield had a three-hole design. The accused infringer argued that the patentee surrendered a range of designs from zero to four holes. However, the Federal Circuit noted that the range concept does not apply to design patents, where only individual designs can be claimed. Thus, while the Federal Circuit upheld the application of prosecution history estoppel to design patent infringement cases in general, it reversed application of the doctrine in this case because the accused design did not fall within the scope of the surrendered designs. The Federal Circuit never reached the issue of what the proper scope of surrender should be for future cases. In dicta the Court implied that estoppel may be determined by applying the “colorable imitation” standard to the surrendered designs. However, in this case the accused infringer admitted its design was not a colorable imitation of the surrendered designs.