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Court Resolves Claim Language Ambiguity Based on Patent Drawing and Expert Testimony

August 03, 2001
Gramenopoulos, C. Gregory

Decision icon Decision

Last Month at the Federal Circuit - September 2001

Judges: Newman (author), Michel, and Gajarsa

In S3 Inc. v. Nvidia Corp., No. 00-1257 (Fed. Cir. Aug. 3, 2001), the Federal Circuit reversed a grant of SJ that claims 1-4 and 9-11 of U.S. Patent No. 5,581,279 (“the ‘279 patent”) are invalid for indefiniteness.

The ‘279 patent relates to video display circuitry in which a clock signal generator circuit, a video controller circuit, and a combination random-access memory (“RAM”)/digital-toanalog converter (“DAC”) are integrated on a single chip. The patent discloses two modes of operation. In the “direct color” mode, pixel data from the video controller is transmitted directly to the DAC for display. In the “indexed” mode, data from the video controller is used to address the RAM to provide higher bit-level color information for display (e.g., 18 or 24 bit-color depth information from only 8 bits of data).

The district court’s ruling of claim indefiniteness focused on the use of the terms “video information data stream” and “video display information data stream” in claims 1 and 9. The Court found claim 1 indefinite due to the use of the term “video information stream” to describe both the information the DAC receives directly from the video controller and the information the RAM receives from the video controller. According to the district court, it is not apparent whether a particular “video information stream” would contain “video information,” “video display information,” or both. The Court found claim 9 invalid for similar reasons.

On appeal, S3 Inc. (“S3”) argued that the claims distinguish between the data stream sent to the DAC and the data stream processed by the RAM, and that this distinction is understood in view of the specification of the ‘279 patent. The Federal Circuit agreed, noting that the specification explains the terms “video information data stream” and “video display information data stream” such that a person skilled in the field of the invention would understand their meaning and scope. According to the Court, a claim is not indefinite simply because it is hard to understand when viewed without the benefit of the specification.

The district court had also found claim 1 indefinite since the “means . . . for selectively receiving either the video information data stream or the video display information data stream” was not disclosed in the specification in accordance with 35 U.S.C. § 112, ¶ 6. Both parties agreed that the “means . . . for selectively receiving” limitation corresponds to the “selector” referred to in the specification. However, the district court held that the ‘279 patent fails to expressly disclose the structure of such selectors.

In reversing the district court’s finding of invalidity, the Federal Circuit noted that it is not the criterion for compliance with § 112, whether a lay person having no skill whatsoever in this field would know how a selector is configured. Instead, based on the uncontradicted expert testimony, the Court held that such a selector was well known in the field and could be readily implemented from the description of the specification.

Judge Gajarsa dissented, characterizing the majority’s analysis as speculative and illusive.