In a recent memorandum opinion, Chief Judge Leonard P. Stark construed claim terms from U.S. Patent No. 5,755,725, entitled “Computer-Assisted Microsurgery Methods and Equipment.” Sarif Biomedical LLC v. Brainlab, Inc., et al., C.A. No. 13-846-LPS (D. Del. Aug. 26, 2015). Of note, Chief Judge Stark found that language in the preamble of a claim was limiting because it provided antecedent basis for a term appearing in other claim limitations. Specifically, the preamble to claim 1 recited “[a] computer-assisted microsurgery installation, comprising . . .” and the word “microsurgery” was not otherwise referenced in the claims, nor described in the specification. The Court agreed with the defendants that the preamble must be limiting because “it provides the antecedent basis for the term ‘the tool,’ which appears later in limitations . . . of the same claim 1.” Id. at 6 (“These later references to ‘the tool’ refer to a microsurgical tool . . . .”).
Chief Judge Stark found, respect to another disputed claim term, that “the presumption against means-plus-function claiming in the absence of the word ‘means’ has been overcome.” Id. at 13. At issue was a claim reciting “a computer adapted to: . . . control position and displacements of the tool as a function of control signals originating from a control unit, wherein the fixed reference frame Rc is independent of the patent reference frame Rp and of the image reference frame Ri.” The Court explained that the “term, and the entirety of the intrinsic (and extrinsic) evidence, fail to recite sufficiently definite structure to accomplish the function of ‘control position and displacements of the tool as a function of control signals originating from a control unit.’” Id. The Court therefore found that the term lacked sufficient disclosure of structure because “there is no disclosure as to how the computer would perform this function. . . . The patent provides no guidance as to how the computer would operate, other than the general assertion that it would run ‘specialized software.’” Id. at 14-15.