“Expert testimony is one example of extrinsic evidence that may be useful in claim construction, but it may not be used to diverge significantly from the intrinsic record”
On April 1, the U.S. Court of Appeals for the Federal Circuit (CAFC) reversed and remanded a summary judgment decision by the U.S. District Court for the Western District of Washington in an infringement suit brought by Genuine Enabling Technology (Genuine) against Nintendo Company and Nintendo of America (collectively “Nintendo”) for allegedly infringing certain claims of Genuine’s U.S. Patent No. 6,219,730 (‘730 patent). The CAFC reversed the district court’s summary judgment decision because the district court erred in its construction of “input signal” and should have construed the term to mean “a signal having an audio or higher frequency.”
In 2001, the ‘730 patent, which was titled “Method and Apparatus for Producing a Combined Data Stream and Recovering Therefrom the Respective User Input Stream and at Least One Additional Input Signal,” was issued to inventor, Nghi Nho Nguyen. The ‘730 patent, invented by Nguyen while developing a “voice mouse” that conserved computer resources, discloses a technology for combining data streams. The ‘730 patent outlines that the prior art consists of computers receiving user input via a “user input device” (IUD) such as a mouse and keyboard. The same computers use “input/output” (I/O) cards to process various types of signals. The ’730 patent explains that these limitations in the prior art can be cumbersome because the devices and cards share computer resources.
The ’730 patent serves to solve these problems by offering “a new kind of IUD utilizing the computer resources efficiently.” The invention utilizes an arrangement that involves the use of a “framer” that receives inputs from both the IUD and external device while synchronizing and merging the data streams into a “combined data stream.” During prosecution, claims 1-27 were rejected as obvious by the examiner. In particular, claims 1, 16 and 23 were rejected by the examiner as obvious in light of U.S. Patent No. 5,990,866 (Yollin).
Yollin notes that in the prior art, pointing devices normally provided two-dimensional motion information for a cursor along with signals for pushing the buttons. A subset of this prior art also processed input known as biofeedback from physiological sensors, which typically required a separate dedicated input device that consumed valuable I/O ports of computer systems and relied on a specialized program. Yollin disclosed “a pointing device with integrated physiological response detection facilities” that “does not consume excess I/O ports.” Yollin additionally described the types of physiological sensors that could be used, but did not specifically discuss the frequency of the signals generated by the physiological sensors.
Regarding the “input signal” limitation, the examiner for the ‘730 patent cited Yollin as a ground for rejection because it taught “input information received from motion translation unit 102, user selection unit 104 and physiological response sensor(s) 106.” Nguyen argued in his office action response that Yollin failed to effectively teach the limitation. Nguyen distinguished the signals in the physiological sensors from the “signals containing audio or higher frequencies” in the ‘730 patent, noting that his ‘730 patent solved the problem of signal collision experience in Yollin. In response to Nguyen’s argument, the examiner entered an amendment withdrawing the rejection and allowing the claims.
District Court’s Analysis
In 2017, Genuine brought an action against Nintendo alleging that five Nintendo Wii and Switch controller products infringed the ‘730 patent. Genuine alleged that the products contained functionality that infringed the claims of the ’730 patent. Both parties submitted claim construction briefs to the district court for the disputed term “input signal.” Genuine proposed that the claim should be constructed as “a signal having an audio or higher frequency.” Alternatively, Nintendo proposed a narrower construction saying that Nguyen disclaimed signals less than 500 hertz and other indefinite amounts. To support their construction, Nintendo submitted a declaration from Dr. Howard Chizeck, which discussed the features and operations of the physiological sensors, similar to those in the Yollin reference. Dr. Chizeck included a chart that provided frequency ranges for signals related to various physiological sensors. Dr. Chizeck opined the maximum frequency of the signals for the sensors from the Yollin reference would be at least 500 hertz. Relying on this declaration, Nintendo argued that a person of ordinary skill in the art would have taught that the sensor signals from the Yollin reference would teach a maximum frequency of 500 hertz and therefore, Nguyen had disclaimed all such signals when distinguishing the ‘730 patent from Yollin during prosecution.
Based on this evidence, Nintendo opposed Genuine’s claim construction and moved for summary judgment of non-infringement. This motion for summary judgment was predicated on the district court’s acceptance of its claim construction for “input signal.” Nintendo contended that their products produce the slow-varying signals that Nguyen disclaimed during prosecution when distinguishing the ‘730 patent from the Yollin reference. In 2020, the district court granted Nintendo’s motion for summary judgment finding construing the “input signal” limitation to mean “signals above 500 Hz and excluding signals generated from positional change information, user selection information, physiological response information, and other slow-varying information” which was consistent with Nintendo’s construction. The district court found Nguyen’s assertions to be a clear expression that if a signal is produced at a frequency contemplated by Yollin, those frequencies do not cause the collision problem when combined with slow-varying signals and are therefore distinct from the signals claimed in the ‘730 patent.
Based on these findings, the district court determined that one skilled in the art would understand the upper bound of the signals in Yollin to set the lower bound for the ‘730 patent. The district court rejected Genuine’s argument, citing Andersen Corp. v. Fiber Composites, LLC (CAFC, 2007), noting that ““an applicant’s argument that a prior art reference is distinguishable on a particular ground can serve as a disclaimer of claim scope.” The district court explained that Nguyen’s distinction over Yollin did not negate his additional statements disavowing slow-varying signals.
Intrinsic vs. Extrinsic Evidence
The CAFC began its analysis by noting that there is an emphasis on the importance of intrinsic evidence in claim construction, while extrinsic evidence can be relied upon in certain scenarios. Expert testimony is one such example of extrinsic evidence that may be useful in claim construction, but it may not be used to diverge significantly from the intrinsic record. The court continued its analysis stating that the doctrine of prosecution precludes patentees from recapturing specific meanings disclaimed during prosecution.
Genuine contended that the prosecution history shows that only slow-varying signals were disclaimed, and the district court erred in its claim construction. Genuine added that the district court incorrectly relied upon the testimony of Dr. Chizeck. The CAFC agreed with Genuine’s arguments, holding:
We conclude that the only disavowal of claim scope that is clear and unmistakable in the record before us is Mr. Nguyen’s disavowal of signals below the audio frequency spectrum. Mr. Nguyen repeatedly distinguished his inventions from Yollin on the grounds that Yollin taught “slow-varying signals” whereas his inventions involved “audio or higher frequency” signals.”
The CAFC further held that the district court incorrectly relied upon the expert testimony, which limited the scope of the claims in a manner not supported by the intrinsic record. Ultimately, the CAFC found the record did not support a finding of a separate and distinct disclaimer of claim scope relating to the particular type of signal.