[J]ust because better alternatives exist in the prior art does not mean that an inferior combination is inapt for obviousness purposes
On June 26, 2012, In In re Mouttet, the U.S. Court of Appeals for the Federal Circuit affirmed the USPTO Board of Patent Appeals and Interferences decision upholding the patent examiner's rejection of the claims of U.S. patent application Serial No. 11/395,232, which related to a computing device for processes such as addition, subtraction, multiplication and division using nanoscale materials in a crossbar array, as obvious. The Federal Circuit stated:
A claimed invention is unpatentable "if the differences between the subject matter sought to be patented and the prior art are such that the subject matter as a whole would have been obvious at the time the invention was made to a person having ordinary skill in the art to which said subject matter pertains." Where "a patent claims a structure already known in the prior art that is altered by the mere substitution of one element for another known in the field, the combination must do more than yield a predictable result." A reference may be read for all that it teaches, including uses beyond its primary purpose.
We find the Board's determination that eliminating the optical components of Falk would not destroy its principle of operation to be supported by substantial evidence. As the examiner found, the type of circuitry used is the main difference between Mouttet's invention, which is based on electrical conductivity, and Falk's invention, which is based on optical paths. But this difference does not affect the operability of Mouttet's broadly claimed device -- a programmable arithmetic processor.
Mouttet further objects that replacing Falk's optical crossbar circuitry with Das's electrical crossbar circuitry would destroy the physical structure of Falk. Mouttet argues that there is no evidence that electrical crossbar circuitry would have been recognized by ordinarily skilled artisans as equivalent to, or able to be substituted for, optical crossbar circuitry. Any alleged nonequivalence in the type of circuit is irrelevant to the Board's determination since the examiner did not rely on art-recognized equivalence in substituting the crossbar arrays. It is well-established that a determination of obviousness based on teachings from multiple references does not require an actual, physical substitution of elements.
Thus, it was not requisite to the Board's § 103(a) determination that Das's features be deemed equivalent for purposes of substitution into Falk's device. Rather, the test for obviousness is what the combined teachings of the references would have suggested to those having ordinary skill in the art. The Board properly found that an electrical engineer with several years of related industry experience would indeed have recognized that Falk's arithmetic processor could have been combined with Das's wired crossbar array to predictably yield Mouttet's claimed computing device.
A reference that properly teaches away can preclude a determination that the reference renders a claim obvious. Whether or not a reference teaches away from a claimed invention is a question of fact. "A reference may be said to teach away when a person of ordinary skill, upon reading the reference, would be discouraged from following the path set out in the reference, or would be led in a direction divergent from the path that was taken by the applicant." Thus, the "mere disclosure of alternative designs does not teach away." This court has further explained that just because better alternatives exist in the prior art does not mean that an inferior combination is inapt for obviousness purposes.
The Board determined that the Falk passage Mouttet recites does not "teach away" from a computing device using an electrical crossbar array under our law. That determination is supported by substantial evidence. Falk indeed recognizes a "fundamental difference" between circuit types, and even suggests that electrical circuits are an inferior to optical circuitry for certain purposes. But the Board found that "even if Falk's [sic] discusses a preferred embodiment (e.g., an optical circuit with more interconnect possibilities), this does not teach away from a non-preferred embodiment containing an arithmetic/logic system having electrical circuitry with wire sets." While Mouttet's reading of Falk is plausible, our standard of review mandates that we uphold factual findings that are supported by substantial evidence as opposed to revisiting them de novo.
As noted by the Board, Mouttet fails to cite any reference suggesting that the claimed invention would be unlikely to work using electrical circuitry; he alleges only that it may be inferior for certain purposes. In this case, a known system such as an arithmetic/logic unit "does not become patentable simply because it has been described as somewhat inferior to some other product for the same use," such as an arithmetic/logic unit having electrical circuitry despite fewer interconnect possibilities than optical circuitry. Nor do we recognize in Falk any teaching -- sufficient to overturn the contrary determination of the Board -- that a crossbar arithmetic processor "should not" or "cannot" be implemented with electrical circuitry, or that "criticize[s], discredit[s], or otherwise discourage[s]" a device like Mouttet's.
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