Does the Specification Adquately Disclose to One of Ordinary Skill the Structure Corresponding to a Means Plus Function Limitation

Aristocrat Technologies Australia PTY LTD., v. Multimedia Games, Inc., [2007-1375](February 22, 2008)[LOURIE, Schall, Bryson] NON-PRECEDENTIAL The Federal Circuit reversed summary judgment that that U.S. Patent 4,817,951 was invalid for indefiniteness.
BRIEF: The ’951 patent is entitled "Player Operable Lottery Machine Having Display Means Displaying Combinations of Game Result Indicia," and describes and claims a machine similar to a slot machine that provides a paperless version of an instant lottery. The district court granted summary judgment that claim 1 was invalid for indefiniteness because the specification of the patent failed to disclose necessary structure corresponding to several of the means-plus-function limitations in the claim. The Federal Circuit said that claim construction of a means-plus-function limitation includes two steps. First, the court must determine the claimed function. Second, the court must identify the corresponding structure in the written description of the patent that performs that function. LOF: The review of indefiniteness under 35 U.S.C. § 112, paragraph 2, proceeds as a question of law without deference. The Federal Circuit found that there were material facts in dispute, and reversed and remanded the determination that the claims were invalid for indefinite.
The Federal Circuit instructed the district court that a presumption applies that a claim limitation that includes the word "means" is intended to invoke means-plus-function treatment. However, that presumption may be rebutted (1) if the claim limitation recites no function corresponding to the means or (2) if the claim limitation itself recites sufficient structure for performing the recited function. The Federal Circuit also rejected the argument that subsidiary means plus function clauses provided sufficient structure to take "control means" out of the province of 35 USC § 112, ¶ 6, not because such clauses could not define structure, but because they did not define structure for performing the functions of the control means. The Federal Circuit said that "Here, it is not clear that the structures allegedly associated with the subsidiary means as a whole are capable of performing all of the functions associated with the parent means." COMMENT: However the Federal Circuit has not previously required that the recited structure perform all of the functions of the recited means to remove it from means plus function treatment. Turning to the definiteness requirement, the Federal Circuit said that the specification must disclose some structure for a means-plus-function limitation. However, the law does not require that structure be explicitly identified as long as a person of ordinary skill in the art would understand what structure is identified in the specification. The Federal Circuit remanded the case for the district court to determine whether the specification adequately disclosed the structure to a person of ordinary skill in the art.