July 2014

Disclosing Only a Class of Algorithms Renders Means-Plus-Function Term Indefinite
Kyle B. Morse*

In Triton Tech of Texas, LLC v. Nintendo of America, Inc., No. 13-1476 (Fed. Cir. June 13, 2014), the Federal Circuit affirmed the district court’s determination that the means-plus-function term “integrator means” was invalid for indefiniteness because the asserted patent failed to disclose an algorithm.

Triton Tech of Texas, LLC (“Triton”) sued Nintendo of America, Inc. (“Nintendo”), alleging infringement of U.S. Patent No. 5,181,181 (“the ’181 patent”) by Nintendo’s Wii Remote™ used in combination with a related accessory.  The ’181 patent discloses an input device that sends commands to a computer based on the input device’s three-dimensional position, attitude (i.e., orientation), and motion.  The ’181 patent describes the input device as including a conventional microprocessor that is programmed to periodically read and numerically integrate values to calculate the position, attitude, and motion values for the input device.  The ’181 patent does not further explain how the numerical integration is performed—only that it is performed in a “conventional manner.”  Slip op. at 3 (citation omitted).  The district court found that the term “integrator means” rendered the asserted claims indefinite because the ’181 patent did not disclose an algorithm for performing the numerical integration.  The district court also determined that “processing means” was indefinite and construed several other terms adversely to Triton.  Triton appealed.

“Disclosing the broad class of ‘numerical integration’ does not limit the scope of the claim to the ‘corresponding structure, material, or acts’ that perform the function, as required by section 112 . . . .  Disclosure of a class of algorithms ‘that places no limitations on how values are calculated, combined, or weighted is insufficient to make the bounds of the claims understandable.’”  Slip op. at 6 (quoting Ibormeith IP, LLC v. Mercedes-Benz USA, LLC, 732 F.3d 1376, 1382 (Fed. Cir. 2013)).

On appeal, the Federal Circuit agreed that “integrator means” rendered the claims indefinite.  First, the Court noted that the term “integrator means” was a means-plus-function term under § 112, sixth paragraph, and that Triton conceded that the corresponding structure was a conventional microprocessor.  The Court rejected Triton’s argument that the ’181 patent disclosed an algorithm for performing the integrating function.  Although the Court recognized that an algorithm can be expressed in many forms, “including flow charts, a series of specific steps, mathematical formula, prose, and so on,” it determined that numerical integration is “an entire class of different possible algorithms,” not an algorithm itself.  Id. at 6.  The Court held that disclosing a class of algorithms neither limits a claim’s scope to the “corresponding structure, material, or acts” that perform the function nor limits how values are calculated in a sufficient way to make the bounds of the claim understandable.  The Court also rejected Triton’s argument that various numerical integration algorithms may have been known to one of ordinary skill in the art.  The Court explained that a “bare statement that known techniques or methods can be used does not disclose structure” for a means-plus-function claim.  Id. (quoting Biomedino, LLC v. Water Techs. Corp., 490 F.3d 946, 953 (Fed. Cir. 2007)).  Even if one of ordinary skill in the art would have known how to select an appropriate algorithm, the Court held that the ’181 patent’s failure to disclose any algorithm rendered the asserted claims indefinite.   

The Federal Circuit next considered Triton’s argument that the ’181 patent disclosed a two-step algorithm consisting of sampling and accumulating.  The Court held that Triton had waived this argument by failing to present it to the district court.  The Court also declined to consider other claim terms that Triton appealed based on its affirmance of indefiniteness based on “integrator means.”  Accordingly, the Court affirmed the district court’s determination of indefiniteness.

*Kyle B. Morse is a Summer Associate at Finnegan.