1. Whether the district court correctly applied the hypothetical claim test to determine whether the accused device did not infringe under the doctrine of equivalents.
2. Whether the district court erred in failing to declare claim six of the allegedly infringing device invalid as obvious.
1. No. The district court correctly applied the hypothetical claim test to determine that the plaintiff's proposed hypothetical claim would be disallowed because it would encompass prior art that was in the public use for more than one year prior to the filing of the '941 patent.
2. No. The district court did not err in its factual finding of non-obviousness. When the defendant does nothing more than claim invalidity based on the same references which the Patent and Trademark examiner reviewed, defendant must overcome the deference granted to the qualified government agency. Defendant did not meet this burden.
Ultra-Tex Surfaces, Inc. and Dryvit Systems, Inc. (collectively Ultra-Tex) are the assignees of U.S. Patent No. 5,502,941 (the '941 patent), that is directed to a process for creating an ornamental imitation brick surface on a concrete substrate. Claim six, the only claim at issue, provides for a flexible, adhesive-backed, heavy wax paper template panel used between the layers of mortar to create the finished product. Claim six is dependent on independent claim five.
Ultra-Tex sued Hill Brothers Chemical Co. and Omega Products Corp. (hereinafter Hill Brothers) for infringement of the '941 patent. Hill Brothers argued that the patent was invalid for obviousness, based on prior art references. The District Court for the Central District of California held that there was no infringement of the '941 patent under the doctrine of equivalents, and that claim six was not invalid for obviousness under 35 U.S.C. § 103. Ultra-Tex appealed the noninfringement ruling and Hill Brothers cross-appealed the decision that claim six was not invalid. Neither side appealed the lower court's finding of no literal infringement.
The Federal Circuit reviews claim construction de novo. The Court found that the district court correctly held that Hill Brothers did not infringe the '941 patent. Ultra-Tex bore the burden of proving the infringement. It did not, however, provide any evidence on the identity of the accused template. Hypothetical claim analysis provides a practical way to determine whether a claim has been impermissibly broadened or narrowed under the doctrine of equivalents. The Court clarified that hypothetical claim analysis should not be used by the patentee to freely redraft claims. The Court also held that once the patentee makes out a prima facie case under the doctrine of equivalents, the patentee must show that the accused infringer's hypothetical claim does not read on prior art. To prove infringement under the doctrine of equivalents, using hypothetical claim analysis, the patentee must produce a hypothetical claim sufficiently broad in scope to literally encompass the accused process. Ultra-Tex proposed a hypothetical claim that both impermissibly narrowed and broadened portions of the '941 patent claim. Ultra-Tex's hypothetical claim was also disallowed because it encompassed prior art processes that were in public use more than one year before the filing date of the '941 patent.
The Court then held that claim six was not invalid for obviousness under 35 U.S.C. 103. There is a statutory presumption of patent validity under 35 U.S.C. § 282. Furthermore, the Court emphasized that the determinations of agency officials are entitled to great deference. Patent invalidity must be proven by clear and convincing evidence. Hill Brothers failed to produce prior art references that were more valid than references presented to the PTO during the '941 application process. Therefore, Hill Brothers failed to meet their burden of proof.
Prepared by the liibulletin-patent Editorial Board.