Opinion ID: 504701
Heading Depth: 3
Heading Rank: 1

Heading: Heart Aid

Text: In its brief to this court ZMI states: 47 ZMI concedes that the Heart Aid models do not literally infringe the claims because they use too high a current (150 ma) to make them tolerable to most conscious patients; thus they lack the required low current and low current density. 48 In view of this admission, the district court's finding of literal infringement must be reversed. ZMI contends, however, that the case must be remanded for findings under the doctrine of equivalents. We disagree. 49 When literal infringement is not found, the equitable doctrine of equivalents comes into play. Under the three-pronged analysis from Graver Tank & Mfg. Co. v. Linde Air Products Co., 339 U.S. 605, 608-09, 70 S.Ct. 854, 94 L.Ed. 1097, 85 USPQ 328, 330 (1950), infringement under the doctrine of equivalents depends on whether the accused device performs substantially the same function in substantially the same way to achieve the same result. 50 To be infringing under the doctrine of equivalents the Heart Aid devices would have to provide low current density to reduce stimulation of local sensory nerves and resulting pain. The concession by ZMI means that the accused devices do not perform substantially the same function (work) in substantially the same way. The Heart Aid devices admittedly do not provide low current density, and because the current transmitted makes them intolerable to most conscious patients they do not reduce stimulation to the local sensory nerves and reduce pain. Thus, they do not perform substantially the same function in substantially the same way and do not infringe under the doctrine of equivalents. Accordingly, there is no need to remand to the district court for a finding as to infringement of the Heart Aid devices under the doctrine of equivalents.