Definition of File wrapper estoppel
Under the doctrine of "file wrapper estoppel,” an applicant who has limited or modified a claim in order to avoid its rejection by the Patent Office may not later expand his claim by including the excluded matter, or its equivalent, or by omitting the limitations period. Speed Shore Corp, v. Denda, C.A.Cal., 605 F.2d 469, 472. Doctrine means that the inventor had earlier given up certain claims with respect to his patent that he is now attempting to assert through the doctrine of equivalents in order to establish a basis for his charge that the patent has been infringed. Systematic Tool & Machine Co. v. Walter Kiddie & Co., Inc., D.C.Pa., 390 F.Supp. 178, 200. See also Prosecution history estoppel.
That's the definition of File wrapper estoppel in Black's Law Dictionary 6th Edition. Courtesy of Cekhukum.com.