Opinion ID: 779640
Heading Depth: 3
Heading Rank: 6

Heading: means for selectively activating said display light sources

Text: 87 The limitation means for selectively activating said display light sources appears in claim 1 of the '619 patent. The district court instructed the jury: 88 The function of this means-plus function element is to control the activation of light sources to illuminate the display area in a first color and the background area in a second color, different from the display area's first color. The function is to activate the display area by passing current through selected light sources of the display area and the background area. The structural components are specified in Figures 3 and 4. 89 Telegenix argues that the court's construction is too broad, and misled the jury to believe that this limitation can be met by any structure broadly suggested by Figure 3, which shows only a block diagram. Telegenix requested an instruction limiting the structure to the circuitry shown in Figure 4. Telegenix also argues that passing current through selected light sources incorrectly identifies the function. 90 TDS argues that its expert testified that means for selectively activating includes hardware, software, and/or firmware for passing current through selected light sources, as supported by Figures 3 and 4. TDS argues that a block diagram such as that shown in Figure 3 may describe structure. 91 TDS argues in favor of a broad interpretation of this claim limitation in reliance on the testimony of its expert. [E]xtrinsic evidence in general, and expert testimony in particular, may be used only to help the court come to the proper understanding of the claims; it may not be used to vary or contradict the claim language. Vitronics, 90 F.3d at 1584, 39 USPQ2d at 1578. Where the patent documents are unambiguous, expert testimony regarding the meaning of a claim is entitled to no weight. Id. `Any other rule would be unfair to competitors who must be able to rely on the patent documents themselves, without consideration of expert opinion that then does not even exist, in ascertaining the scope of a patentee's right to exclude.' Id. (quoting Southwall Techs., 54 F.3d at 1578, 34 USPQ2d at 1678-79). Thus, where the patent documents are unambiguous, reliance upon the testimony of TDS's expert witness would be improper. 92 We hold, and the parties do not dispute, that this limitation is in means-plus-function form and thus is subject to 35 U.S.C. § 112, paragraph six. As stated above, in construing such a limitation, the task of the district court is first to identify the function recited for the limitation and next to identify the corresponding structure in the written description necessary to perform that function. See Micro Chem., 194 F.3d at 1258, 52 USPQ2d at 1263. 93 The district court misidentified the recited function by including in the construction, The function is to activate the display area by passing current through selected light sources of the display area and the background area. This reference to passing current has no basis in the claim language. See Generation II Orthotics, 263 F.3d at 1364-65, 59 USPQ2d at 1926 (When construing the functional statement in a means-plus-function limitation, we must take great care not to impermissibly limit the function by adopting a function different from that explicitly recited in the claim.); Micro Chem., 194 F.3d at 1258, 52 USPQ2d at 1263 (The statute does not permit limitation of a means-plus-function claim by adopting a function different from that explicitly recited in the claim.). 94 Likewise, the district court's identification of the corresponding structure was incomplete. The description in the specification of the structure corresponding to the recited function is not limited to Figures 3 and 4, as instructed, but also includes the written description accompanying these Figures. See '619 patent, col. 3, ll. 34-68, and col. 4, ll. 1-61. Moreover, as Figure 3 and its accompanying text serve merely as overview for introducing and explaining Figure 4, the corresponding structures must necessarily be found in Figure 4. 95 We conclude that the means for selectively activating performs the function of illuminat[ing] certain of said display areas in a first color, and said background light sources, to illuminate said background regions in a second color different from said first color. The corresponding structure in the specification is described in Figure 4 and the accompanying written description, including the overview provided by Figure 3 and the written description accompanying that Figure. The means for selectively activating is limited to this corresponding structure and equivalents thereof. 96