United States Federal Circuit Court Holds That The Doctrine Of Prosecution History Estoppel Applies To Design Patents

In Pacific Coast Marine Windshields Ltd v Malibu Boats, a decision released January 8, 2014, the United States Federal Circuit Court of Appeals confirmed that the doctrine of prosecution history estoppel applies to design patents. The Doctrine of Prosecution History Estoppel Prosecution history estoppel is a doctrine in US patent law that applies in situations where an inventor files a patent application and subsequently makes amendments to the application that narrow its scope for the purpose of complying with patentability requirements. This doctrine provides that in actions alleging infringement of the resulting patent, the court may not adopt a construction of the patent’s claims that would encompass the material that the patentee removed from the patent application during the prosecution stage. The doctrine of prosecution history estoppel developed in the context of utility patents, which protect the functionality of a product or process. US case law has established that utility patents may be infringed both literally and under the doctrine of equivalents. Literal infringement occurs when all the elements of an allegedly-infringing product or process correspond identically to all the elements claimed in a patent. Infringement under the doctrine of equivalents occurs when there are only “insubstantial differences” between the elements of the impugned product or process and the elements claimed in the patent. Under the doctrine of prosecution history estoppel, a patentee may not employ the doctrine of equivalents to argue that a court should construe a patent’s claims to include material he or she surrendered during patent prosecution. Because the doctrine of prosecution history estoppel developed in the context of utility patents, US law had not been clear on whether it applies to design patents, which only relate to a product’s appearance. This was mainly because the test for infringement of a design patent differs significantly from the test for infringement of a utility patent; the concept of literal infringement does not exist in the context of design patents. Case law has established that the test for infringement of a design patent is whether “in the eye of an ordinary observer, giving such attention as a purchaser usually gives, the allegedly-infringing design is “substantially the same” as the patented one. In Pacific Coast, after a review of prior case law, the Federal Circuit Court concluded that the test for infringement of a design patent “involves the concept of equivalents”, and that therefore, the doctrine of prosecution history estoppel should apply to design patents. The Court’s Decision in Pacific Coast Pacific Coast was a patent infringement action in which Pacific Coast Marine Windshields Ltd argued that Malibu Boats had infringed a patent it held that covered an ornamental design for a marine windshield (the ’070 Patent). The ’070 Patent had resulted from a patent application filed by Darren A. Bach, Pacific’s owner and chief executive officer, who later assigned his patent rights to Pacific. The patent examiner had determined that the application contained five “patentably distinct groups of designs” and issued a restriction requirement forcing Bach to select one of the five groups for the pending application. The group Bach selected comprised a design with four circular vent holes and a corner hatch. While it was open to him to file divisional patent applications for the four other groups of designs the original application had encompassed, he only did so for one such group. The design that Pacific alleged infringed the ’070 Patent was of a boat windshield with three trapezoidal vent holes and no hatch. Malibu argued that the doctrine of patent prosecution estoppel precluded Pacific from arguing that Malibu’s design infringed the ’070 Patent because the allegedly-infringing design was within the scope of the claims Bach had removed from his original patent application in order to comply with the restriction requirement the examiner had imposed. Having concluded that the doctrine of prosecution history estoppel applies to design patents, the Federal Circuit Court considered whether this doctrine barred Pacific from arguing that Malibu’s design infringed its patent. In finding that prosecution history estoppel applied in that case, the Court rejected Pacific’s argument that the doctrine only covers narrowing amendments made to avoid prior art. Citing case law establishing that “a narrowing amendment made to satisfy any requirement of the Patent Act may give rise to an estoppel”, the court held that “in the design patent context, the surrender resulting from a restriction requirement invokes prosecution history estoppel if the surrender was necessary...‘to secure the patent’”. The court’s finding in Pacific Coast that the doctrine of prosecution history estoppel applies to design patents underlines the need to use careful strategy when filing design patent applications. If the United States Patent and Trademark Office determine that an original application contains more than one patentably distinct design and issues a restriction requirement, an applicant may be well advised to consider filing divisional applications for the withdrawn designs, in order to build a strong design patent portfolio that can help guard against future infringement. Summary by: Kathryn May