Insufficient Extrinsic Evidence and Prosecution Disclaimer Led to Claim Construction in Patentee’s Favor
| May 6, 2022
Decided: April 1, 2022
Newman, Reyna, and Stoll. Opinion by Reyna.
Summary
The CAFC found in favor of a patentee seeking broad interpretation of a claim term, where an expert testimony offered by an opponent in support of narrower claim scope was insufficient to overcome a clear record of the patent, and the prosecution history lacked “clear and unmistakable” statements to establish express disavowal of claim scope.
Details
This is an appeal from a district court action where Genuine Enabling Technology LLC (“Genuine”) sued Nintendo Co., Ltd. and Nintendo of America, Inc. (“Nintendo”) for infringing certain claims of U.S. Patent No. 6,219,730. The patent relates to user input devices, such as mouse and keyboard, and its representative claim 1 recites:
1. A user input apparatus operatively coupled to a computer via a communication means additionally receiving at least one input signal, comprising:
user input means for producing a user input stream;
input means for producing the at least one input signal;
converting means for receiving the at least one input signal and producing therefrom an input stream; and
encoding means for synchronizing the user input stream with the input stream and encoding the same into a combined data stream transferable by the communication means.
(Emphasis added.)
The inventive idea may be pictured as a “voice mouse.” As seen in Fig. 1B of the patent, the inventive apparatus or mouse 18, connected with a computer 10 via a communication link 12, serves the traditional function of allowing user to move an object 14 on the computer monitor 13 (i.e., “user input means for producing a user input stream”), while also capable of receiving a speech input from a microphone 16 (i.e., “input means for producing the at least one input signal”) and transmitting a speech output to a speaker 17.
At issue in the case is the construction of the term “input signal.”
During prosecution, the inventor distinguished his invention over U.S. Patent No. 5,990,866 (“Yollin”) cited in an office action, arguing that the “input signal” limitation was missing in the reference. Specifically, the inventor argued that various physiological sensors disclosed in Yollin, such as those detecting user’s muscle movement, heart rate, brain activity, blood pressure, skin temperature, etc., only produce “slow varying” signals as opposed to “signals containing audio or higher frequencies” to which his invention pertains. The inventor pointed out that the inventive apparatus would resolve a specific problem presented by the use of high frequency signals, which, unlike slow varying signals, tend to “collide” with other signals in producing a composite data stream. This “slow varying” vs. “audio or higher frequencies” distinction is repeatedly noted in the inventor’s argument.
The parties disputed the extent of prosecution disclaimer resulting from the inventor’s statements as to the term “input signal.” In the district court, Genuine proposed to construe the term as
“a signal having an audio or higher frequency,”
whereas Nintendo maintained that the proper scope should be narrower:
“A signal containing audio or higher frequencies. [The inventor] disclaimed signals that are 500 Hertz (Hz) or less. He also disclaimed signals that are generated from positional change information, user selection information, physiological response information, and other slow-varying information. Alternatively, indefinite.”
Nintendo argued that the inventor disclaimed the certain types of “slow-varying” signals taught by Yollin. While specific frequencies were not disclosed in Yollin, Nintendo relied on its expert testimony citing a reference purportedly showing that Yollin’s physiological sensors encompassed the range of “at least 500 Hz.”
Genuine contended that the disclaimed scope should be limited to “slow-varying signals below the audio frequency spectrum [of 20 Hz to 20,000 Hz],” in accordance with the inventor’s argument which only had distinguished the reference “slow-varying” signals from “fast-varying” signals.
The district court sided with Nintendo, finding non-infringement in its favor. In particular, the district court noted that “an applicant’s argument that a prior art reference is distinguishable on a particular ground can serve as a disclaimer of claim scope even if the applicant distinguishes the reference on other grounds as well.” Andersen Corp. v. Fiber Composites, LLC, 474 F.3d 1361, 1374 (Fed. Cir. 2007). That is, according to the district court, the fact that the inventor’s argument distinguished Yollin as lacking “audio or higher frequencies” did not negate the effect of the inventor’s statement also distinguishing Yollin’s range as “slow-varying” signals.
On appeal, the CAFC rejected the district court’s claim construction.
First, the CAFC noted that the role of extrinsic evidence in claim construction is limited, and cannot override intrinsic evidence where there is clear written record of the patent. And as one form of extrinsic evidence, “expert testimony may not be used to diverge significantly from the intrinsic record.” Here, the 500 Hz frequency threshold was not identified in the intrinsic record nor Yollin, and its only basis was Nintendo’s expert testimony which relied on another extrinsic reference that was not in the record. The extrinsic evidence conflicted with the prosecution history in which the examiner had accepted the inventor’s argument distinguishing Yollin without drawing a bright line between “slow-varying” and “audio or higher frequenc[y]” signals. As such, the CAFC found that the expert testimony cannot overcome the clarity of the intrinsic evidence.
Second, the CAFC noted that prosecution disclaimer requires that the patentee make a “clear and unmistakable” statement to disavow claim scope during prosecution. The fact that the inventor repeatedly distinguished the reference “slow-varying” signals from “audio or higher frequenc[y]” signals—the argument which successfully traversed the rejection—led the CAFC to decide that the “clear and unmistakable” disavowal was limited to “signals below the audio frequency spectrum.” Although the CAFC noted that the inventor’s statements “may implicate” certain frequency ranges such as 500 Hz or less, the intrinsic record was not unambiguous enough for the particular range to be disclaimed. For similar reasons, the CAFC also found no disclaimer of “signals that are generated from positional change information, user selection information, physiological response information, and other slow-varying information,” which had not been directly addressed in the inventor’s argument.
The CAFC concluded that the district court erred in the claim construction and that the proper scope of the term “input signal” is “a signal having an audio or higher frequency.”
Takeaway
This case provides a reminder that caution should be taken not to make “clear and unmistakable” statements in arguing around the prior art during prosecution. Although there appears to be no fixed criteria for assessing what qualifies as a “clear and unmistakable” disavowal, applicant’s consistency in presenting one main argument—focused on an essential distinction between the claim and the prior art—without introducing unnecessary details may help limit the extent of potential prosecution disclaimer.
