Federal Circuit Finds Means–Plus–Function Algorithm Claim Invalid for Indefiniteness


Ibormeith IP, LLC v Mercedes-Benz USA, LLC By Aditya Gupta – Edited by Kathleen McGuinness

Ibormeith IP, LLC v. Mercedes-Benz USA, LLC, No. 13- 1007 (Fed. Cir. October 22, 2013) Slip opinion

[caption id="attachment_3821" align="alignleft" width="150"] Photo By: Craig Dennis - CC BY 2.0[/caption]

The United States Court of Appeals for the Federal Circuit affirmed a decision of the United States District Court for the District of New Jersey, which had held on summary judgment that certain means-plus-function claims of Ibormeith IP, LLC's ("Ibormeith") US Patent No. 6,313,749 ("the '749 Patent") - "Sleepiness Detection for Vehicle Driver or Machine Operator" - were invalid for indefiniteness under 35 U.S.C. § 112. Ibormeith IP, slip op. at 2.

The Federal Circuit held that the claim element “computational means” expressed a means for performing a specified function and thus was subject to the requirements of 35 U.S.C. § 112(f), which governs such means-plus-function elements. Id. at 2-3. According to the court, the ‘749 Patent failed to comply with 35 U.S.C. § 112(f) because it failed to adequately define the structure for the “computational means” limitation in the specification. Id. at 7. In so holding, the court noted that Ibormeith’s arguments regarding the breadth of its disclosure, for the purpose of infringement, must also be held against it as “binding admissions” for the purposes of a 35 USC §112(f) inquiry into claim validity. Id. at 10-11.

PatentlyO summarizes the case's facts and holding and comments on the ramifications of the decision with respect to litigation strategy. iPFrontline briefly explains the decision and the lessons it provides for practitioners.

The ‘749 Patent described a “sleepiness monitor” that provided a vehicle driver or machine operator with an audio-visual sleepiness warning. Id. at 2-3. Ibormeith sued Mercedes-Benz USA, LLC and Daimler AG (collectively, "Defendants") for infringement of the patent. Id. at 4. The Defendants filed a motion for summary judgment of the patent's invalidity, arguing that the “computational means” claim limitations were indefinite. Id. at 5.

Under 35 U.S.C. § 112(f), a claim element expressed as a means for performing a specified function (a "means-plus-function" element) is construed to cover the structures, and equivalents thereof, described in the patent specification. Id. According to Federal Circuit precedent, the specification must disclose a specific structure to support a means-plus-function limitation, without which a claim is fatally indefinite under 35 U.S.C. § 112(f) for failing to particularly point out and distinctly claim the invention. Id.

The specification of the ‘749 Patent defined a set of input variables for determining the sleepiness of the driver or machine operator and a “sleep propensity algorithm,” represented as the sum of those variables. Id. at 8. Ibormeith relied on this algorithm as the structural support for the “computational means” element. Id. at 5. According to Ibormeith’s expert, the algorithm did not disclose the mere addition of the input variables but instead equally covered all ways of taking into account the listed variables, or some subset of the variables, that a skilled artisan would find appropriate. Id. at 11.

For a claim to be definite, it must be "sufficiently defined to render the bounds of the claim . . . understandable by the implementer." Id. at 7. The court found that the sleep propensity algorithm, if interpreted as proposed by Ibormeith, was insufficient to make the bounds of the claim definite and understandable because a person skilled in the art "would need to devise his or her own method for determining driver drowsiness" based on the variables listed in the specification. Id. at 11. Further, the court held that because the description of the algorithm placed "no limitations on how values of the variables are calculated, combined, or weighted," it was insufficient to make the bounds of the claim understandable. Id. at 12. Finally, the court noted that Ibormeith’s broad interpretation of the “computational means” element - to cover the Defendant's allegedly infringing products - must bind it when considering the claim's definiteness. Id. at 10-11.

This case typifies one litigation dilemma for patent plaintiffs, who must propose a claim construction that is broad enough to cover the accused product but at the same time avoid an construction broad enough to render the claim indefinite. PatentlyO suggests, with approval, that the Federal Circuit’s decision was motivated by a desire to hold parties to their litigation admissions, but it notes that this constraint still allows patentees to maintain ambiguity in their claims until litigation arises.