That Word -- I Don't Think it Means What You Think It Means

Microprocessor Enhancement Corporation v. Texas Instruments Incorporated, [2007-1249, -1286] (April 1, 2008) [GAJARSA, Newman, Dyk] The Federal Circuit reversed summary judgment of invalidity for indefiniteness, but affirmed summary judgment of noninfringement.
SIGNIFICANCE: Structure in a method claim, or function in an apparatus claim is not necessarily fatal. A word can have different meanings in the same claim if it is clear from the context.
BRIEF: The district court concluded that independent claims 1 and 7 of the ’593 patent are invalid for indefiniteness on the grounds that both claims impermissibly mix two distinct classes of patentable subject matter and that the claims are insolubly ambiguous for requiring that a single word be interpreted differently in different portions of a single claim. The Federal Circuit said that a claim is considered indefinite if it does not reasonably apprise those skilled in the art of its scope. Because a claim is presumed valid, a claim is indefinite only if the ‘claim is insolubly ambiguous, and no narrowing construction can properly be adopted. LOF: Whether a claim reasonably apprises those skilled in the art of its scope is a question of law that is reviewed de novo. Regarding the mixed subject matter of the claims, as to the method claim1, the Federal Circuit said method claim preambles often recite the physical structures of a system in which the claimed method is practiced, and found that claim 1 was no different. The Federal Circuit similarly found that the apparatus claim 7, apparatus claims are not necessarily indefinite for using functional language.
Addressing the fact that “condition code” was used inconsistently throughout the claims, the Federal Circuit rejected the district court’s conclusion that the term had to have the same meaning throughout the claim. The Federal Circuit said that a single term, used consistently, had to be given the same meaning. The Federal Circuit found that the meaning of the term could change form the contact, and that the claims’ apparent nonsensical reading under a uniform construction of “condition code” is indicative of the ease of determining the appropriate meaning of each use of the term from its context.
The issue of infringement turned on claim construction. The Federal Circuit said that it ascertains the meaning of a disputed term by looking to “‘those sources available to the public that show what a person of skill in the art would have understood disputed claim language to mean.’” These source include the words of the claims themselves, the remainder of the specification, the prosecution history, and extrinsic evidence. The Federal Circuit examined each source and found no error in the district court’s construction.