Negative Claim Construction Found Inadequate

| Justin J. Gillett


Before Prost, Mayer, and Taranto. Appeal from the United States District Court for the Central District of California.

Summary: It was improper to find a claim limitation was missing without affirmatively construing the limitation and instead relying on its relation to a term not shown to have a sufficiently uniform meaning in the art.

Sound View Innovations, LLC (“Sound View”) sued Hulu, LLC alleging infringement of a patent claim related to streaming multimedia. The district court construed the claim to require a “buffer.” On summary judgement, to satisfy the “buffer” requirement, Sound View pointed to components that the accused system labeled as “caches.” The district court noted that the asserted patent also used the term “caches” to identify components, and that the patent describes those components as distinct from “buffers.” The district court therefore held that the accused components labeled as “caches” could not be the required “buffers” and granted summary judgement of non-infringement. Sound View appealed.

The Federal Circuit reversed the non-infringement determination. It noted that, to the extent the district court construed the term “buffer,” all it did was declare what it must exclude (a “cache”). The Federal Circuit acknowledged there is no per se rule against negative constructions. But it held the district court’s negative construction in this case did not enable a comparison between the required “buffer” and the accused product. The Court noted there had been no determination that the term “cache” has a sufficiently uniform meaning in the art. Absent such a determination, it reasoned, a conclusion that the asserted patent distinguishes “caches” from “buffers” does not preclude a finding that accused components labeled as “caches” practice the required “buffers.” Further, the Federal Circuit held an affirmative construction of “buffer” was needed for the additional reason that the asserted patent does not appear to use the terms “buffer” and “cache” in a mutually exclusive manner. The Court therefore vacated the entry of summary judgment of non-infringement and remanded.

Editor: Paul Stewart