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Preferred Embodiment Does Not Limit Claim Scope of Mouse Patent

June 26, 2001

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Last Month at the Federal Circuit - July 2001

Judges: Linn (author), Lourie, and Rader

In Gart v. Logitech, Inc., No. 00-1088 (Fed. Cir. June 26, 2001), the Federal Circuit provided a new claim construction for a limitation in the asserted claim and, as a result, vacated a SJ of noninfringement by Logitech, Inc. (“Logitech”). The Court also reversed the district court’s finding that two letters from Samuel Gart to Logitech did not effect the statutory notice of infringement requirement under 35 U.S.C. § 287(a) for certain Logitech products.

U.S. Patent No. 4,862,165 (“the ‘165 patent”) discloses an ergonomically shaped computer mouse for reducing muscle fatigue. The district court had construed the phrase “an angular medial surface for supporting the three remaining ulnar fingers in a wrapped configuration with flexion of the distal, middle, and proximal phalanges of said ulnar fingers” of claim 7 to require that the mouse housing have “an angular ledge” for supporting the three fingers in an enclosed or folded position. Although both parties suggested that the district court had also construed the “angular ledge” to include a curved undercut or concave depression, the Federal Circuit stated that the district court’s opinion was not clear on this point.

Logitech, supporting the district court’s claim construction, contended that (1) all of the drawings of the ‘165 patent show a ledge with an undercut area; and (2) the written description describes the invention as having a “medial ledge undercut” that is not related to the preferred embodiment. The Federal Circuit reasoned that the specification and the prosecution history should be consulted to construe the language of the claims when the patentee has chosen to be his or her own lexicographer, or when the language itself lacks sufficient clarity such that there is no means by which the scope of the claim may be ascertained from the language used. Otherwise, terms in the claim are to be given their ordinary and accustomed meaning.

The Court noted that the description in the specification that Logitech relied upon is merely a description of the preferred embodiment. The Court also noted that the specification clearly states that “an angular medial surface” without the ledge will achieve the object of the invention. Further, the Court determined that the drawings only depict the preferred embodiment and were not meant to limit the scope of coverage defined by the claims. Thus, the Court concluded that the written description of the invention does not explicitly limit the subject matter of the patent to the ledge configuration.

Logitech further argued that Gart made statements in the specification distinguishing the prior art, noting in particular that three references did not include an undercut ledge. The Court countered, however, that the specification also stated that those same references did not contain all of the ergonomic surface features of the invention or were incompatible with the surface shapes needed in a hand controller. Thus, the Court concluded that Gart did not limit the claims by distinguishing the prior art.

Further, the Court did not agree with Logitech that in allowing the claims the Examiner had implied that “an undercut area” was novel and nonobvious because the Examiner never explicitly stated that the patentable difference over the prior art was “the concave undercut area” of the claimed device. The Court determined that drawing inferences of the meaning of claim terms from an Examiner’s silence is not a proper basis on which to construe a patent claim.

With the new claim construction, the Court could not determine with certainty based on the factual record before it whether there were any genuine issues of material fact regarding infringement, either literally or under the DOE, by the accused products. Accordingly, the Court vacated the district court’s grant of SJ of no infringement and remanded the case for further proceedings.

Regarding the notice issue, there were two letters from Gart to Logitech that the Court analyzed. The first letter stated that Logitech “may wish to have patent counsel examine the . . . patent . . . to determine whether a non-exclusive license under the patent is needed” for a first product. The second letter stated that Logitech might find the patent “particularly interesting” relative to a second product and the first product. Supporting the district court’s decision, Logitech contended that both letters did not use the word “infringement” and, thus, were insufficient actual notice because they were at best an invitation for Logitech to study the patent to determine whether there might be infringement. The Court disagreed that notice was insufficient without an unqualified charge of infringement and a threat of suit.

Reversing the district court, the Court held that no reasonable jury could find that Logitech was not notified of infringement by the first product from the first letter. The Court reached this conclusion because the first letter reasonably suggested to Logitech that Gart had believed the making and selling of the first product infringed the ‘165 patent claims. The Court did not believe that the second letter alone was sufficient notice of infringement because it did not reasonably convey that Gart had believed Logitech was infringing the ‘165 patent claims. Again reversing the district court, the Court nonetheless found that no reasonable jury could find that Logitech was notnotified of the infringement of the second product. The Court came to this conclusion because the second letter, in conjunction with the first letter, reasonably apprised Logitech that Gart had believed that the making and selling of the second product infringed the ‘165 patent.