Hilmer doctrine and US patent reform

The Hilmer Doctrine

The current version of 35 USC § 102(e) provides

A person shall be entitled to a patent unless—

(e) the invention was described in – (1) an application for patent, published under section 122(b), by another filed in the United States before the invention by the applicant for patent . . . except that an international application . . . shall have the effects for the purposes of this subsection of an application filed in the United States only if the international application designated the United States and was published . . . in the English language

This means that a published U.S. patent application (or published PCT application that designated the U.S. and was published in English) can be cited as prior art as of its U.S. (or PCT) filing date.

The Hilmer doctrine, based on the 1966 CCPA case of In re Hilmer, holds that such an application is notcitable as of its foreign priority date. That is, under the Hilmer doctrine, a foreign priority claim can be used as a shield against intervening prior art, but not as a sword against intervening inventions.

Patent Reform Eliminates The Hilmer Doctrine

New 35 USC § 102(a)(2) (which takes effect March 16, 2013) eliminates the Hilmer doctrine and gives prior art effect to U.S. patent applications as of their foreign filing dates:

(a) NOVELTY; PRIOR ART.—A person shall be entitled to a patent unless—

(2) the claimed invention was described in a patent issued under section 151, or in an application for patent published or deemed published under section 122(b), in which the patent or application, as the case may be, names another inventor and was effectively filed before the effective filing date of the claimed invention.

This change means that U.S. applications with foreign priority claims will be citable up to 12 months earlier than they are now, assuming that the PCT or U.S. Paris Convention application was filed 12 months after the foreign priority application was filed.