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District Court Improperly Interpreted Functional Claim Limitations as Means-Plus-Function Limitations

April 02, 2003

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Last Month at the Federal Circuit - May 2003

Judges: Gajarsa (author), Newman, and Rader

In Apex, Inc. v. Raritan Computer, Inc., No. 02- 1303 (Fed. Cir. Apr. 2, 2003), the Federal Circuit vacated the district court’s judgment of noninfringement of U.S. Patent Nos. 5,884,096 (“the ‘096 patent”), 5,937,176 (“the ‘176 patent”), and 6,112,264 (“the ’264 patent”)(collectively “the patents”), and remanded the case for further proceedings. The Federal Circuit ruled that Defendant had not overcome the presumption that the lack of the term “means” in the asserted claims suggests that the claims are not in means-plus-function form and the claims are not limited by disclosure of a preferred embodiment.

Apex, Inc. (“Apex”) is the assignee of the patents, which relate to computer-switching systems for connecting computer workstations to remote computers.

After a seven-day bench trial, the district court construed twelve of fourteen disputed claim limitations as means-plus-function limitations and found no infringement.

The Federal Circuit found that the district court had erred in its interpretation of the claims, particularly given that Raritan Computer, Inc. had not overcome the rebuttable presumption that § 112, ¶ 6 does not apply.

The Federal Circuit found enough in the record to address “first interface circuit” and “second interface circuit” limitations in the claims. Looking to dictionary definitions, it found several examples for an “interface circuit.” The written description and prosecution history provided no evidence that the inventors intended the term “interface circuit” to have a meaning contrary to this ordinary meaning. Characterizing the record as poorly developed, the Federal Circuit suggested that the district court conduct a similar analysis with respect to the remaining limitations at issue.