In 1998, Mr. Nguyen filed a patent application and obtained a patent number U.S Patent No.6,219, 730 (the “730 Patent”) in 2001. The 730 patent disclosed technology for combining data streams conceived when developing a voice mouse for computer resources.

In February 2017, Genuine Enabling Technology LLC (“The Appellant”) instituted an action at the United States District Court for the District of Delaware against Nintendo Co Ltd and Nintendo of America Inc. (collectively “The Respondent”) for infringement on the 730 patent. 

The Appellant alleged that five products of the Respondent infringed upon the 730 patent. The suit was later transferred to the United States District Court for the Western District of Washington (“The District Court”).


After submitting issues before the District Court, the Respondent moved for summary judgment for non-infringement. The motion was predicated on the District Court’s acceptance of the Respondent’s claim construction of input signal.

The Respondent argued therein that its accused controllers produce slow-varying signals. The signals are the type that Mr. Nguyen (on the Appellant’s behalf) disclaimed when distinguishing his inventions from the Yollin reference.

The District Court issued an order granting the Respondent’s summary judgment motion for non-infringement. The aggrieved Appellant appealed to the United States Court of Appeal for the Federal Circuit (“The Federal Circuit”).

The Federal Circuit disagreed and upturned the decision of the District Court. The basis being that the District Court placed too much reliance on an expert’s opinion as part of its claim construction analysis.

The Federal Circuit said an expert testimony, which is extrinsic evidence, might be helpful in claim construction. Mainly to provide background on the technology at issue and explain how the invention works.

However, expert testimony should not be used to diverge significantly from an intrinsic record. Therefore, reliance on expert evidence regarding claim construction is permissible where it is consistent with the intrinsic evidence.

The Federal Circuit held that the District Court applied a threshold, 500Hz, which was based solely on an expert opinion. The expert opinion was said to be extrinsic evidence, which was not part of the intrinsic record but extrinsic sources.

As a result, the Respondent’s claim construction on the input signal was disregarded for being too narrow. Instead, the claim construction was that the maximum frequency of signals from physiological sensors is at least 500Hz.

The Federal Circuit said that the proper construction of the input signal is a signal having audio or higher frequency. This was in accordance with the Appellant’s claim construction at the District Court.


Flowing from above, it is evident that the Federal Circuit reversed and modified the construction by the District Court. First, the Federal Circuit applied the principle regarding the extrinsic nature of expert testimony.

Since extrinsic evidence inconsistent with an intrinsic record could not be relied upon, the decision of the District Court was overruled. This was because the District Court heavily relied on extrinsic expert evidence.


Disclaimer: The views and opinions expressed throughout this blog are the views and opinions of the individual author(s) and/or contributor(s) and do not necessarily reflect the views and opinions of our firm, CIONCA IP Law. P.C. 

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  • CIONCA IP TEAM (SE)4/8/2022 4:51:08 PM


Marin Cionca | Founder of CIONCA IP

Marin Cionca, Esq.

Registered Patent Attorney

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About CIONCA® IP Law firm: We are an Irvine, Orange County, California based boutique intellectual property law firm with a focus on patent and trademark application, prosecution, opinion, licensing and IP enforcement services, including IP litigation, offering its IP services, other than IP litigation, primarily at flat fee rates. We serve local OC (Orange County) clients, as well as clients from the Los Angeles, San Diego and Riverside Counties and clients throughout the state of California, the United States and also international clients, such as EU clients.

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