Executive Intellectual Property Bulletin
CAFC Rules on Doctrine of Equivalence
The Risk of Infringement Has Just Gone Up.
In a landmark and controversial patent case that will be reviewed by the US Supreme Court, the Court of Appeals for the Federal Circuit (the court which hears all patent appeals) ruled in Hilton Davis Chemical Co. v. Warner-Jenkinson Company, Inc., No. 93-1088 (Fed. Cir. August 8, 1995) that the test for infringement under the Doctrine of Equivalents is broader than we all thought and is an issue to be decided by a jury. This case injects a greater degree of uncertainty into a determination of whether one infringes another's patent. The Doctrine of Equivalents (DOE) allows a court of law to broaden the interpretation and scope of the claims of a patent even if the claims do not literally read on the accused device or process. The DOE is a judicial doctrine (not based on any statute) and is based on the facts of each situation. In effect, the DOE protects a patent owner from one who may make insubstantial changes in the invention to avoid literal infringement.
The risk of infringement under the DOE has always been difficult to predict since it must be determined if the accused device performs substantially the same function in a substantially same way to obtain substantially the same result (called the "function-way-result" test). In addition, one must consider a number of mitigating factors such as whether the patent is a "pioneering invention", how similar the patent is to the prior art and how much the patent owner gave up in the Patent Office in attempting to obtain the patent in the first place. Taken together, accurately predicting whether a court will find infringement under the DOE is a pretty iffy undertaking.
The problem of predicting infringement under the DOE got even tougher under Hilton Davis. The court held that the application of the DOE rests on the substantiality of the differences between the patent and the accused products or processes. The function-way-result test often suffices to answer the question of infringement, but it does not end the inquiry. Now, other evidence may also be relevant to the substantiality of the differences between the products. Even more harrowing is that the jury has the sole task of deciding infringement under the DOE, not the judge.
Why the new evidence as factors in infringement? Well, the court decided that the earlier Supreme Court decision which defined the DOE test in 1950 in Graver Tank & Mfg. Co. Inc. v. Linde Air Products Co., (cite omitted) was decided in a era of relatively simple mechanical technology. The Court of Appeals for the Federal Circuit decided last week that technology has become more sophisticated and the old function-way-result test is insufficient to show the substantiality of the differences between the patent claims and the accused device or process. The court stated that one must also look to other objective indicators of substantiality such as the known interchangeability of elements, evidence of copying to show insubstantial changes and evidence of "designing around" to show substantial changes. Evidence of independent development is irrelevant to the analysis of substantiality in the Hilton-Davis analysis but can be used to rebut evidence of copying. What this means to our friends and clients is that the law of infringement is getting more difficult to predict. We are already a patent-aware society but awareness of your competitors' patents may not be enough. You must also be wary of how closely your products copy your competitors patented inventions since patent litigation now carries the additional risk of getting a unpredictable jury result based upon the Doctrine of Equivalents.
For more information on this topic and how the Hilton-Davis decision may affect US industry and trade, please contact any one of our attorneys at Schwegman, Lundberg & Woessner, P.A. at 612-339-0331 or by facsimile at 612-339-3061.
