How does changing the principle of operation of a reference affect obviousness?
Changing the principle of operation of a prior art reference can negate an obviousness rejection. As stated in MPEP 2143.01, “If the proposed modification or combination of the prior art would change the principle of operation of the prior art invention being modified, then the teachings of the references are not sufficient to render the claims prima facie obvious.” This principle, established in cases like In re Ratti, ensures that obviousness rejections are based on combinations that maintain the fundamental functioning of the prior art references.
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Topics:
MPEP 2100 - Patentability,
MPEP 2143.01 - Suggestion Or Motivation To Modify The References,
Patent Law,
Patent Procedure