Can the prosecution history affect how the preamble is interpreted?
Yes, the prosecution history can significantly affect how the preamble is interpreted. According to MPEP 2111.02:
“[C]lear reliance on the preamble during prosecution to distinguish the claimed invention from the prior art transforms the preamble into a claim limitation because such reliance indicates use of the preamble to define, in part, the claimed invention.”
This principle is illustrated in cases like Catalina Mktg. Int’l v. Coolsavings.com, Inc. and Metabolite Labs., Inc. v. Corp. of Am. Holdings. If an applicant relies on the preamble to overcome prior art during prosecution, it may become a limiting part of the claim.
However, without such reliance, preamble language merely extolling benefits or features of the claimed invention generally does not limit the claim scope.
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