Linda Chan, Paralegal
Recent decisions by the Federal Circuit have ruled that obviousness under 35 USC 103 can be based upon a single prior art reference. While anticipation rejections under 35 USC 102 have always been able to rely a single prior art reference that, within its four corners, discloses all of the elements recited in a patent claim, historically obviousness rejections usually required more than one reference. In fact, obviousness rejections were traditionally used when a single reference did not disclose all of the claim elements, and two or more prior art references must be combined to provide all of the elements, obviousness is the normal route to establishing unpatentability.
In some cases, obviousness has been found where only a single prior art reference, which didn’t disclose all of the claim elements, was cited, and “common sense” was cited to provide the missing element(s). In such cases, the Federal Circuit has ruled that the application of common sense requires explicit and objective support. In its decision in Arendi v. Apple, 832 F.3d 1355, 1363, 119 USPQ2d 1822, 1827 (Fed. Cir. 2016), the Federal Circuit stated: “[W]e conclude that while ‘common sense’ can be invoked, even potentially to supply a limitation missing from the prior art, it must still be supported by evidence and a reasoned explanation. In cases in which ‘common sense’ is used to supply a missing limitation, as distinct from a motivation to combine, moreover, our search for a reasoned basis for resort to common sense must be searching. And, this is particularly true where the missing limitation goes to the heart of an invention.”
In In re Stepan Co., 660 F.3d 1341 (Fed. Cir. 2011) the court stated that: “Absent some additional reasoning, the Board’s finding that a skilled artisan would have arrived at the claimed invention through routine optimization is insufficient to support a conclusion of obviousness.” In that case, the Patent Trial and Appeal Board failed to explain their reasoning for applying a single prior art reference how a person of ordinary skill in the art, applying common sense, could extend the teachings of that single reference to arrive at the claimed subject matter. According to the Federal Circuit in Stepan, “Under Title 35, examiners must explain obvious rejections with findings that includes facts as to how a person of ordinary skill would have understood prior art teachings.”
To sum up, obviousness of a patent claim can be established with only a single prior art reference being cited, but if common sense is cited to extend the teachings of that single reference, there must be an explanation, supported by explicit and objective evidence, provided. The burden of establishing obviousness, when a single reference is cited along with “common sense”, is on the one asserting that the patent claims are unpatentable for obviousness, and not on the applicant or patentee.