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§ 1.657 Burden of proof as to date of invention. - PATENT RULES
§ 1.657 Burden of proof as to date of invention.
(a) A rebuttable presumption shall exist that, as to each count, the inventors made their invention in the chronological order of their effective filing dates. The burden of proof shall be upon a party who contends otherwise.
(b) In an interference involving copending applications or involving a patent and an application having an effective filing date on or before the date the patent issued, a junior party shall have the burden of establishing priority by a preponderance of the evidence.
(c) In an interference involving an application and a patent and where the effective filing date of the application is after the date the patent issued, a junior party shall have the burden of establishing priority by clear and convincing evidence.
[49 FR 48466, Dec. 12, 1984, added effective Feb. 11, 1985; revised, 60 FR 14488, Mar. 17, 1995, effective Apr. 21, 1995]
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