Opinion ID: 771385
Heading Depth: 2
Heading Rank: 1

Heading: The Doctrine of Equivalents and Prosecution History Estoppel

Text: 20 The doctrine of equivalents prevents an accused infringer from avoiding liability for infringement by changing only minor or insubstantial details of a claimed invention while retaining the invention's essential identity. Graver Tank & Mfg. Co. v. Linde Air Prods. Co., 339 U.S. 605, 608 (1950). The doctrine of equivalents is utilized '[t]o temper unsparing logic and prevent an infringer from stealing the benefit of the invention.' Id. (quoting Royal Typewriter Co. v. Remington Rand, Inc., 168 F.2d 691, 692, 77 USPQ 517, 518 (2d Cir. 1948) (Hand, J.)). In pursuing these goals, the doctrine attempts to strike a balance between ensuring that the patentee enjoys the full benefit of his patent and ensuring that the claims give fair notice of the patent's scope. London v. Carson Pirie Scott & Co., 946 F.2d 1534, 1538, 20 USPQ2d 1456, 1458-59 (Fed. Cir. 1991). This balance can be easily upset, however, because the doctrine of equivalents, when applied broadly, conflicts with the definitional and public-notice functions of the statutory claiming requirement. Warner-Jenkinson, 520 U.S. at 29. 21 Prosecution history estoppel is one tool that prevents the doctrine of equivalents from vitiating the notice function of claims. Charles Greiner & Co. v. Mari-Med Mfg., Inc., 962 F.2d 1031, 1036, 22 USPQ2d 1526, 1529-30 (Fed. Cir. 1992). Actions by the patentee, including claim amendments and arguments made before the Patent Office, may give rise to prosecution history estoppel. Pharmacia & Upjohn Co. v. Mylan Pharms., Inc., 170 F.3d 1373, 1376-77, 50 USPQ2d 1033, 1036 (Fed. Cir. 1999). Prosecution history estoppel precludes a patentee from obtaining under the doctrine of equivalents coverage of subject matter that has been relinquished during the prosecution of its patent application. Id. at 1376, 50 USPQ2d at 1036. Therefore, [t]he doctrine of equivalents is subservient to . . . [prosecution history] estoppel. Autogiro Co. v. United States, 384 F.2d 391, 400-01, 155 USPQ 697, 705 (Ct. Cl. 1967). The logic of prosecution history estoppel is that the patentee, during prosecution, has created a record that fairly notifies the public that the patentee has surrendered the right to claim particular matter as within the reach of the patent.