The U.S. Court of Appeals for the Federal Circuit held that an applicant’s silence in response to the unilateral statement of an examiner regarding claim scope made in stating reasons for allowance does not reflect the necessary clear and unambiguous disavowal of claim scope or acquiescence so as to give rise to prosecution history estoppel. Salazar v. Procter & Gamble Co., Case No. 04-1013 (Fed. Cir. July 8, 2005) (Rader, J.)
Salazar brought suit against Procter & Gamble (P&G), alleging infringement of Salazar’s patent claiming a toothbrush with "elastic stimulator rods and elastic polishing rods." During prosecution, the examiner rejected the sole independent claim as obvious over two prior art references and objected to the remaining dependent claims as allowable subject matter dependent upon a rejected base claim. Salazar canceled the original claims and filed new claims based on the allowable subject matter. The examiner issued the claims without rejection. In the notice of allowance, however, the examiner stated the claims were allowable because, although the prior art recited "rods" made of nylon, nylon is not considered to be "elastic." The notice of allowance was the first and only time during prosecution that the examiner mentioned the term "elastic." Salazar did not respond to the examiner’s statement.
P&G moved for summary judgment on the ground its accused toothbrushes do not include the "elastic" limitation. Based on the examiner’s remark in the notice of allowance, the district court construed the term "elastic" as "any material other than nylon, capable of returning to an initial state or form after deformation." Based on that construction, the court granted summary judgment of no literal infringement and also held the doctrine of prosecution history estoppel barred Salazar from asserting infringement under the doctrine of equivalents. Salazar appealed.
The Federal Circuit reversed and remanded for further proceedings, noting that, in construing claims, the court must consider the prosecution history to determine whether the applicant clearly and unambiguously disclaimed any interpretation of a claim during prosecution in order to obtain allowance. The Court further noted that under Festo, prosecution history estoppel serves to limit the doctrine of equivalents when an applicant clearly and unmistakably surrenders subject matter through arguments made to the examiner. The Court also noted, however, that under the applicable U.S. Patent and Trademark Office regulations, an applicant is not required to respond to the unilateral statements of an examiner in stating reasons for allowance and held that if the applicant declines to respond, it is not deemed to have acquiesced to those reasons. On that basis, the Court concluded an applicant’s silence or lack of response to an examiner’s unilateral statement of reasons for allowance does not amount to a clear and unambiguous disavowal of claim scope or a clear and unmistakable acquiescence to the examiner’s characterization.
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