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Negative Claim Construction May Not Be Enough If There Is No Uniform Meaning for What Is Being Excluded

Posted by James Juo | May 16, 2022 | 0 Comments

The accused infringer in patent litigation will sometimes propose a negative claim construction that excludes a feature or aspect of the accused product, and thus avoid infringing the patent claim. But if the excluded feature does not have a uniform meaning in the art, then a more affirmative construction may be needed.

In Sound View Innovations LLC v. Hulu LLC, No. 21-1928 (Fed. Cir. May 11, 2022), the Court of Appeals for the Federal Circuit considered whether a negative claim construction was enough to resolve the infringement dispute.

The asserted patent, U.S. Patent No. 6,708,213 (“the `213 patent”), titled “Method for Streaming Multimedia Information over Public Networks,” claimed a method involving a content server and intermediate helper servers for streaming multimedia (SM) object, which required “allocating a buffer” at a helper server “to cache” at least a portion of the SM object.

The district court determined that the claimed “buffer” cannot cover “a cache” because the `213 patent describes buffers and caches in different locations, and otherwise distinguishing between “buffers” and “caches.”  For example, the `213 patent defines “cache” as “a region on the computer disk that holds a subset of a larger collection of data”; and although the patent does not define “buffer,” it describes “ring buffers” located “in the memory” of the helper servers.

The district court reasoned that because the `213 patent uses the terms “buffer” and “cache” to refer to distinct physical components, then a cache could not satisfy the limitation of claim 16 requiring a buffer.

The district court then granted summary judgment of non-infringement because the accused product used a cache and did not download and retrieve subsequent portions of the same SM object in the same buffer.

To the extent that the district court performed the first step of an infringement analysis—claim construction—all it did for the term at issue, “buffer,” was to declare what it must exclude (a “cache”). The court did not adopt an affirmative construction of what constitutes a “buffer” in this patent. But “‘[a]lthough there is no per se rule against negative constructions,' which in some cases can be enough to resolve the relevant dispute,” [Intel Corp. v. Qualcomm Inc., 21 F.4th 801, 811 (Fed. Cir. 2021) (citation omitted)], the court's construction here was inadequate for the second step of an infringement analysis—comparison to the accused products or methods.

The Federal Circuit found that that the term “cache” was not “a term of such uniform meaning in the art” that its meaning in the `213 patent must be relevantly identical to its meaning when used by those who labeled the pertinent components of the accused product.

In the absence of such a uniformity-of-meaning determination, the district court's conclusion that the '213 patent distinguishes its buffers and caches is insufficient to support a determination that the accused-component “caches” are outside the “buffers” of the '213 patent. What was needed was an affirmative construction of “buffer”— which could then be compared to the accused-component “caches” based on more than a mere name.

The Federal Circuit also found that the terms “buffer” and “cache” do not appear to be mutually exclusive, but instead seem to have at least some overlap in their coverage as used in the `213 patent.

The disputed claim describes “allocating a buffer . . . to cache” a portion of the SM object, '213 patent, col. 14, lines 39–40 (emphasis added), and the specification explains that “the ring buffer . . . operates as a type of short term cache” because it is capable of servicing multiple client requests within a certain time interval, id., col. 7, lines 20–22 (emphasis added). This intrinsic evidence suggests the absence of mutual exclusivity in general usage of the terms.

Noting that a dictionary definition of the term “buffer” was “temporary storage for data being sent or received,” the Federal Circuit remanded the case back to the district court to determine whether to conduct further proceedings on what affirmative construction should be adopted.

The attorneys at Thomas P. Howard, LLC are experienced in prosecuting and litigating patents nationwide including in Colorado.

About the Author

James Juo

James Juo is an experienced intellectual property attorney. He has successfully litigated various intellectual property disputes involving patents, trademarks, copyrights, and trade secrets. He also has counseled clients on the scope and validity of patent and trademark rights.


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