patents lightbulb patent lockPatent practice thrives on fine distinctions between a new invention and the prior art. From the fertile field of fine distinctions grow rules of thumb, generalizations, presumptions, sayings, and canards intended to be helpful. Discussed here is “routine optimization,” an approach to obviousness in cases where the gap between the prior art and patent claims appears to be one that the hypothetical person of ordinary skill in the art would necessarily bridge in the ordinary course of development.

The origin of “routine optimization” as an indicium of obviousness. Patents may not grant to “obvious” inventions. 35 U.S.C. §103(a) (patent may not be obtained “if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious … to a person having ordinary skill in the art”). To facilitate the examination of patent applications, examiners may reject claims that are prima facie obvious over the prior art. If the examiner makes a prima facie showing, the burden shifts to the applicant to come forward with evidence to rebut the examiner’s case. Because the burden shifts to the applicant only if the examiner’s prima facie showing was adequate, precedent developed around the standard of adequacy, including cases holding that types of differences that commonly separated a proposed claim from the prior art were sufficient to support an examiner’s prima facie showing.