Opinion ID: 209426
Heading Depth: 2
Heading Rank: 3

Heading: Additional Claim Constructions

Text: Respironics requests that we construe various other terms that were not determinative in the district court’s infringement analyses. We have, on occasion, exercised our discretion to construe such terms in the interest of judicial efficiency. Here, we decline to construe any additional terms in the ’802 and ’193 patents, because the district court correctly found no infringement of those patents under the term “selected higher and lower pressure magnitudes,” and because those patents do not present any remaining issues on remand. See Inpro II Licensing, S.A.R.L. v. T-Mobile USA, Inc., 450 F.3d 1350, 1352 (Fed. Cir. 2006) (declining to construe additional terms where noninfringement was affirmed under dispositive term and where no validity issues remained). However, because we have held, supra, that a remand is necessary to reconsider both infringement of the ’575 patent and anticipation of the ’575 and ’517 patents, we shall review the disputed claim constructions of those patents. See Chimie v. PPG Indus., Inc., 402 F.3d 1371, 1375 n.2 (Fed. Cir. 2005) (construing second term after vacating summary judgment of noninfringement under first term, where “the construction of this second disputed term was not dispositive to the district court’s decision, but may be relevant on remand”).
Respironics argues that “fluid characteristic” in the claims of the ’575 and ’517 patents should not be limited to just “flow rate,” because the specification also discloses 2008-1164, -1193 24 “volume” as a fluid characteristic. See ’575 patent col.23 ll.65-67 (“said fluid characteristic is one of a rate of said flow of gas within said patient interface and a volume of gas to be exhaled”) (emphases added). We agree that the claim construction should be modified to include volume. Although volume can be calculated from flow rate, such a calculation would require additional steps to be performed: measuring time and then multiplying time by average flow rate (or integrating a time-varying flow rate). Aside from volume, however, Respironics points to no other fluid characteristic disclosed in the specification. Nor do we see any. Thus, properly construed, “fluid characteristic” means “flow rate or volume.”
Respironics also contends that the phrase “corresponding to” means something more than just “equal to.” For the reasons stated above, our review here is limited to the term’s use in the “sensing” step of the ’517 patent’s claim 29, which recites: “sensing a fluid characteristic associated with the flow of breathing gas and outputting a signal corresponding to the fluid characteristic.” (emphasis added). In this context, we agree with Respironics that “corresponding to” is broader than “equal to.” This particular step recites a “fluid characteristic,” which we have construed, supra, to mean flow rate or volume. It would make no sense, then, to say that a flow rate or volume is “equal to” a signal, when the specification speaks of electrical signals that are typically measured in units of voltage or current. Two such things cannot be equal to one another. Rather, it is more proper to say that the two are functionally related to one another: the magnitude of the outputted signal varies as a function of the magnitude of the sensed flow rate or volume. These two things “correspond to” one another in the sense that they are 2008-1164, -1193 25 “similar, comparable, and/or matching”—the term’s plain and ordinary meaning. Because the modified construction is broader than the construction under which infringement was found, our modification of “corresponding to” does not disturb the finding of infringement.