An Algorithm in Means-Plus-Function Claims Must Adequately Define Structure to Avoid Indefiniteness
October 22, 2013
Judges: Lourie, Prost, Taranto (author)
[Appealed from: D.N.J., Judge Hochberg]
In Ibormeith IP, LLC v. Mercedes-Benz USA, LLC, No. 13-1007 (Fed. Cir. Oct. 22, 2013), the Federal Circuit affirmed a district court’s grant of SJ of indefiniteness in favor of defendants Mercedes-Benz USA, LLC and Daimler AG (collectively “Mercedes”).
U.S. Patent No. 6,313,749 (“the ’749 patent”) discloses a sleepiness detection safety system for vehicle drivers or machine operators. The monitor system disclosed in the ’749 patent takes into account several factors related to sleepiness—e.g., driver behavior and time of day—which are “individually weighted, according to contributory importance, and combined in a computational decision algorithm or model” to warn drivers of sleepiness. Slip op. at 2 (citation omitted).
Independent claims 1 and 9 of the ’749 patent contain a “computational means” element subject to the requirements of 35 U.S.C. § 112(f)—formerly paragraph 6 of 35 U.S.C. § 112—as means-plus-function claims. Claim 1 requires that the means account for “sleepiness-related time-of-day information” and to produce an output that triggers a warning, if necessary. Claim 9 focuses on the driver’s steering to provide a warning indication of driver sleepiness.
Ibormeith IP, LLC (“Ibormeith”), assignee of the ’749 patent, sued Mercedes for infringement. Mercedes moved for SJ of indefiniteness, arguing that the means-plus-function “computational means” limitations were indefinite. While Ibormeith argued that the required structure included algorithms found in the specification, the district court held that cited portions of the specification were inadequate to disclose the needed structure, and granted SJ for Mercedes. Ibormeith appealed.
On appeal, the Federal Circuit affirmed the district court’s grant of SJ of indefiniteness. The Court explained that § 112(f) “allows patentees to put structural details into the specification and build into the literal coverage of the claim a certain scope for equivalents in performing a defined function.” Id. at 7. The Court noted that means-plus-function claims must be “tied to a structure defined with sufficient particularity in the specification,” and while the structure “need not be so particularized as to eliminate the need for any implementation choices by a skilled artisan,” the structure must be sufficiently defined to render the bounds of the claim understandable by the implementer. Id. Ibormeith recognized that the structure required for the claimed “computational means” must be an algorithm that must be found in the specification. The only substantial issue for the Federal Circuit then was whether such an algorithm was adequately disclosed in Table 10 of the specification, along with two figures and any other specification material that would clarify the meaning of Table 10. The Court found that the disclosed algorithm did not adequately define the structure.
In scrutinizing the relevant sections of the specification, the Court noted that Table 10 included “what looks like a mathematical equation” followed by several factors. Id. at 8. Further, Figures 3 and 17 depict how sleepiness varies throughout the day, with Figure 17 including lines representing warning threshold levels. According to Ibormeith, the factors in Table 10 may relate to driver drowsiness. But, the Court noted that “there is no disclosure of even a single concrete relationship between the various factors that are used to compute an outcome to warn of driver drowsiness.” Id. at 9. Rather, Ibormeith’s expert described Table 10 as a template used for creating a specific formula or equation, and that certain terms are optional or less important than others. Ibormeith’s expert explained that simply adding the weighted factors is insufficient for the algorithm, and one implementing the drowsiness detection system would need to decide which factors to use; how to obtain, weight, and combine them; and when to issue the warning.
The Court, acknowledging that this broad reading of Table 10 was an attempt by Ibormeith to reach the accused products, treated Ibormeith’s position as to Table 10’s breadth as a binding admission. Thus, the Court explained that Table 10 could be interpreted as covering all ways of considering the listed factors, or a subset thereof, that a skilled artisan would consider appropriate. Such a reading of Table 10, the Court found, “leaves the disclosure without an algorithm whose terms are defined and understandable.” Id. at 11. Moreover, the Court noted, Table 10 does not disclose how to weight the factors; it merely lists those factors without explaining how to arrive at a computed warning indicator. Nor could Ibormeith rely on Figures 3 and 17 to provide the requisite structure to support Table 10. The figures, the Court explained, merely provided information that one “skill[ed] in the art could use to design his or her own method of weighting.” Id. at 11-12. As such, the Court affirmed the district court’s judgment of indefiniteness.
Summary authored by Andrew E. Renison, Law Clerk at Finnegan.