Doctrine of Equivalents
On May 28, 2002, a unanimous United States Supreme Court issued its decision in the much anticipated case of Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co., LTD. The Supreme Court vacated and remanded the case, reaffirmed Warner Jenkinson, and perhaps most importantly the Court rejected the complete-bar approach to the doctrine of equivalents adopted by the Federal Circuit in all cases where amendments are made during prosecution of the patent. The Court did, however, place upon the patentee “the burden of showing that the amendment does not surrender the particular equivalent in question.”On September 26, 2003, the Federal Circuit issued the follow up opinion in Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki (Fed. Cir., 2003) – On remand from the US Supreme Court, the sole issue before the Federal Circuit was whether Festo can rebut the presumption that the filing of narrowing amendments for the two patents in suit surrendered all subject matter between the original claim limitations and the amended claim limitations. The Federal Circuit concluded that Festo cannot overcome that presumption by demonstrating that the rationale underlying the narrowing amendments bore no more than a tangential relation to the accused equivalents or by demonstrating that there was “some other reason” such that the patentee could not reasonably have been expected to have described the accused equivalents. However, the Federal Circuit did remand to the district court in order for the district court to determine whether Festo can rebut the presumption of surrender by establishing that the equivalents in question would have been unforeseeable to one of ordinary skill in the art at the time of the amendments.
More recently, however, in Honeywell International Inc. v. Sundstrand Corp., 2004 U.S. App. LEXIS 10754 (Fed. Cir., June 2, 2004), the Federal Circuit seems to have all but killed any claim for equivalent infringement for the foreseeable future. In a very disappointing (and intellecutally dishonest) decision, the Federal Circuit, sitting en banc, held that the rewriting of dependent claims into independent form coupled with the cancellation of the original independent claims creates a presumption of prosecution history estoppel.
Doctrine of Equivalents Basics
A party who fails to prove literal infringement claim may prove infringement under the doctrine of equivalents when the differences between the claimed invention and the accused device are insubstantial. Pall Corp. v. Micron Separations, Inc., 66 F.3d 1211, 1218 (Fed.Cir.1995), cert. denied, — U.S. —-, 117 S.Ct. 1243, 137 L.Ed.2d 326 (1997). The Supreme Court has emphasized that the focus of the analysis under this doctrine must be on each separate element of the invention, rather than on the invention as a whole. Warner-Jenkinson Co., Inc. v. Hilton Davis Chem. Co., 520 U.S. 17, 117 S.Ct. 1040, 137 L.Ed.2d 146 (1997). The Court stated:
Each element contained in a patent claim is deemed material to defining the scope of the patented invention, and thus the doctrine must be applied to individual elements of the claim, not to the invention as a whole. It is important to ensure that the application of the doctrine, even as to an individual element, is not allowed such broad play as to effectively eliminate that element in its entirety.
Id. at 1049.
Elaborating on the Doctrine of Equivalents
Below is an excerpt from Festo Corp. v. Shoketsu Kinzoku Kogyo Kabushiki Co., Ltd., 234 F.3d 558, 564-565 (Fed. Cir. 2000), which has since been vacated by the United States Supreme Court. In vacating and remanding the case, the US Supreme Court specifically rejected the complete-bar approach to amendments and the doctrine of equivalents adopted by the Federal Circuit. Nevertheless, the below excerpt does adequately, succinctly and quite correctly state the general law applicable to the doctrine of equivalents. In Festo the majority decision of the Federal Circuit explained:
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 Products 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 Co., Inc. v. Hilton Davis Chemical Co., 520 U.S. 17, 29 (1997).
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.
The Reverse Doctrine of Equivalents
“[W]here a device is so far changed in principle from a patented article that it performs the same or a similar function in a substantially different way, but nevertheless falls within the literal words of the claim, the doctrine of equivalents may be used [in reverse] to restrict the claim and defeat the patentee’s action for infringement.” Graver Tank & Mfg. Co. v. Linde Air Prods. Co., 339 U.S. 605, 608-09, 70 S.Ct. 854, 856, 94 L.Ed. 1097 (1950)) (alteration in original); see also Boyden Power-Brake Co. v. Westinghouse, 170 U.S. 537, 568, 18 S.Ct. 707, 722, 42 L.Ed. 1136 (1898) (“The patentee may bring the defendant within the letter of his claims, but if the latter has so far changed the principle of the device that the claims of the patent, literally construed, have ceased to represent his actual invention, he is as little subject to be adjudged an infringer as one who has violated the letter of a statute has to be convicted, when he has done nothing in conflict with its spirit and intent.”).