Prosecution history

Beyond the immediate context of the claims themselves, claim language should never be taken out of its broader context. In the realm of patents, this broader context includes the entire specification as well as the prosecution history of the patent.31 While claim terms are given their normal and customary usage, the normal... 

The patent prosecution history is also considered to be part of the intrinsic record and is publicly available for applications that have published. 

The basic effect of the doctrine of equivalents is to allow the patent owner to expand the scope of protection afforded by the literal language of the claims. However, the doctrine of equivalents does not allow the patent owner to expand the scope of the claims without restriction. The ability of the patent owner to expand the scope of the patent claims is restrained by the prior art and also by the doctrine of prosecution history estoppel. 

The doctrine of prosecution history estoppel also limits the degree to which the claims may be interpreted under the doctrine of equivalents. The doctrine of prosecution history estoppel precludes the patent owner from interpreting the claims in a manner that would encompass, within the claim, subject matter that the patent owner surrendered during prosecution of the patent application to achieve issuance of the patent. Any subject matter that the patent owner surrendered during prosecution to obtain allowance of claims made in the application of the patent cannot be reclaimed under the doctrine of equivalents. 

Although the Festo decision would lend certainty to the determination of patent scope, there is concern that it represents an overly rigid approach that will, in effect, severely restrict patent rights. The Supreme Court recently vacated the Federal Circuit s Festo decision and returned the case to the Federal Circuit for further consideration. The claim scope actually surrendered with the amendment will, however, apparently remain an important consideration in applying the doctrine of equivalents and prosecution history estop-... 

Note that in the case of selection inventions claiming unexpected potency or selectivity, data to back that up may have been submitted to the patent examiner but never published in the application or patent so that no direct comparison can be made short of delving into the patent prosecution history to try and find it there. 

A considerable part of a patent attorney s practice may be focused on providing legal opinions regarding the scope and validity of third party patents to determine whether there is freedom to operate for a particular product, or whether the product would infringe another party s patent. In the biotechnology industry, this may include an analysis of patents relating to the synthesis of a product, the product itself, and formulations of the product, as well as its method of use. This task also involves an analysis of prosecution histories of other patents, relevant prior art, and consideration of whether the patent of interest satisfies the statutory requirements for patentability. 

Additional guidelines, relating to the doctrine of equivalents and the rule of prosecution history estoppel, and based on the Supreme Court decisions in the cases of Festo Corporation v. Shoketsu Kinzoku Kogyo Kabushiki Co., Ltd., 122 S.Ct. 1831 (2002) and Warner Jenkinson Company, Inc., v. Hilton Davis Chemical Co., 117 S.Ct. 1040 (1997), shed light on the limits and requirements of a finding of infringement under the doctrine of equivalents, as follows ... 

Prosecution history estoppel requires that claims of a patent be interpreted in hght of proceedings in patent office during the prosecution process,... 

Prosecution history estoppel may apply to any claim amendment made to satisfy a statutory requirement of the patent act,... 

A patentee alleging inflingement under the doctrine of equivalents can rebut the presumption that the prosecution history estoppel bars a finding of equivalence by showing that at the time of amendment one skilled in the art could not reasonably be expected to have drafted a claim that would have literally encompassed the alleged equivalent, and... 

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