The applicants’ statement during the prosecution may play a critical role for claim construction
| July 4, 2022
Sound View Innovations, LLC v. Hulu, LLC
Decided: May 11, 2022
Prost, Mayer (Sr.) and Taranto. Court opinion by Taranto.
Summary
On appeals from the district court for summary judgment of noninfringement of a patent, directed to a method of reducing latency in a network having a content server, the Federal Circuit affirmed the district court’s construction of the down-loading/retrieving limitation solely on the basis of prosecution history, but the Court rejected the district court’s determination that “buffer” cannot cover “a cache,” and vacated the district court’s grant of summary judgment and remanded for further proceedings.
Details
I. Background
(i) The Patent in Dispute
Sound View Innovations, LLC (“Sound View”) owns now-expired U.S. Patent No. 6,708,213 (“the ’213 patent”), which describes and claims “methods which improve the caching of streaming multimedia data (e.g., audio and video data) from a content provider over a network to a client’s computer.” Claim 16 of the ’213 patent provides as follows:
16. A method of reducing latency in a network having a content server which hosts streaming media (SM) objects which comprise a plurality of time-ordered segments for distribution over said network through a plurality of helpers (HSs) to a plurality of clients, said method comprising:
receiving a request for an SM object from one of said plurality of clients at one of said plurality of helper servers;
allocating a buffer at one of said plurality of HSs to cache at least a portion of said requested SM object;
downloading said portion of said requested SM object to said requesting client, while concurrently retrieving a remaining portion of said requested SM object from one of another HS and said content server (the “downloading/retrieving limitation”); and
adjusting a data transfer rate at said one of said plurality of HSs for transferring data from said one of said plurality of helper servers to said one of said plurality of clients (emphasis added).
During the prosecution, the examiner rejected original claim 16—which was identical to issued claim 16 except that it lacked the downloading/retrieving limitation—as anticipated over DeMoney (U.S. Patent No. 6,438,630). To overcome the rejection, the applicants amended the claim to add the downloading/retrieving limitation. The applicants explained that support for the added limitation is found in the applicants’ specification, pointing to the portion of the specification that shows concurrent downloading and retrieval involving a single buffer (emphasis added). In fact, the specification nowhere says that the invention includes use of separate buffers for the concurrent downloading and retrieving functions, and it nowhere illustrates or describes such an embodiment, in which different buffers are involved in con- current downloading of one portion and retrieving of a remaining portion of the same SM object in response to a given client’s request.
(ii) The District Court
Sound View sued Hulu, LLC (“Hulu”) for infringement of six Sound View patents including the ’213 patent in the United States District Court for the Central District of California (“the district court”). As the case proceeded, only claim 16 of the ’213 patent remained at issue.
It was undisputed that the accused edge servers— the edge servers Sound View identified as the “helper servers” for its infringement charge—do NOT download and retrieve subsequent portions of the same SM object in the same buffer (emphasis added).
Sound View alleged, among other things, that, under Hulu’s direction, when an edge server receives a client request for a video not already fully in the edge server’s possession, and obtains segments of the video seriatim from the content server (or another edge server), the edge server transmits to the Hulu client a segment it has obtained while concurrently retrieving a remaining segment.
The district court agreed with Hulu’s argument that the applicants’ statements accompanying the amendment in the prosecution disclaimed the full scope of the downloading/retrieving limitation, and that the downloading/retrieving limitation thus required that the same buffer in the helper server—the one allocated in the preceding step—host both the portion sent to the client and a remaining portion retrieved concurrently from the content server or other helper server (emphasis added).
In reliance on the construction, Hulu then sought summary judgment of non-infringement of claim 16, arguing that it was undisputed that, in the edge servers of its content delivery networks, no single buffer hosts both the video portion downloaded to the client and the retrieved additional portion. Sound View countered that there remained a factual dispute about whether “caches” in the edge servers met the concurrency limitation as construed. The district court held, however, that a “cache” could not be the “buffer” that its construction of the down- loading/retrieving limitation required, and on that basis, it granted summary judgment of non-infringement. A final judgment followed.
Sound View timely appealed.
II. The Federal Circuit
The Federal Circuit (“the Court”) affirmed the district court’s construction of the down-loading/retrieving limitation. but the Court rejected the district court’s determination that “buffer” cannot cover “a cache,” and vacated the district court’s grant of summary judgment and remanded for further proceedings.
Claim Construction (the downloading/retrieving limitation)
The Court first noted that this is not a case in which the other intrinsic evidence—the claim language and specification—establish a truly plain meaning contrary to the meaning assertedly established by the prosecution history because the downloading/retrieving limitation, which does not expressly refer to “buffers,” contains no words affirmatively making clear that different buffers in the helper server may be used for the sending out to clients of one portion of the SM object and the receiving of a retrieved remaining portion.
The Court viewed the prosecution history as establishing that the applicants made clear that the applicants’ invention concurrently empties and fills the buffer, while the DeMoney reference teaches filling the buffer only after the buffer is empty,” citing column 12, lines 28–40 of DeMoney (emphasis added).
Based on the applicants’ statements, the Court agreed with the district court that the applicants limited claim 16 to using the same buffer for the required concurrent downloading and retrieval of portions of a requested SM object.
Summary Judgment of Non-Infringement
After the district court adopted its “buffer”-requiring claim construction of the downloading/retrieving limitation, it granted summary judgment of non-infringement, concluding that accused-system components called “caches”—on which Sound View relied for its allegation of infringement under the court’s claim construction—could not be the required “buffers.” The district court relied for its conclusion on the ’213 patent’s references to its described “buffers” and “caches” as distinct physical components. To support the conclusion, the district court noted that the ’213 patent describes buffers and caches in different locations: The 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 HS.
However, the Court stated that the district court’s construction here was inadequate for the second step of an infringement analysis (comparison to the accused products or methods) because it did not adopt an affirmative construction of what constitutes a “buffer” in this patent. More specifically, the Court stated that the district court did not decide, and the record does not establish, that “cache” is 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 edge servers. The Court thus concluded that, 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.
For an additional reason for the further affirmative construction, the Court pointed out that, even in the ’213 patent, the terms “buffer” and “cache” do not appear to be mutually exclusive, but instead seem to have at least some overlap in their coverage given that the disputed claim describes “allocating a buffer . . . to cache” a portion of the SM object, and that 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 (emphasis added).
Takeaway
· Claim construction: The applicants’ statement during the prosecution may play a critical role for claim construction if the claim language and specification do not establish a truly plain meaning of a disputed term contrary to the meaning assertedly established by the prosecution history.
· Summary Judgment: Portions of the specification may provide genuine issue of material fact for denial of summary judgment (in this case, the embodiment describes buffers and caches in different locations while the disputed claim provides “allocating a buffer . . . to cache”)
