On June 26, 2012, the U.S. Court of Appeals for the Federal Circuit upheld the decision of the USPTO Board of Patent Appeals and Interferances (the “Board”) to deny all claims pending in U.S. Patent Application No. 11/385,232 (“Application ‘232”). Application ‘232, entitled “Crossbar Arithmetic Processor,” discloses a computing device for processes such as addition, subtraction, multiplication, and division using nanoscale materials in a crossbar array. The USPTO examiner rejected these claims under § 103(a) as unpatentable over three prior art references.
The examiner found that Falk taught all of the limitations in this claim “except for (1) a crossbar array implemented with electrical wires rather than optical light paths, (2) crosspoints with programmable states based on electrical conductivity rather than optical intensity, and (3) conversion of analog signal outputs to digital output bit patterns in the post-processing units.” The examiner concluded that Das filled the first and second missing elements, determining that Das teaches a nanoscale crossbar array with molecular switches capable of being programmed to construct functional circuits that can be used to build larger processor systems. The examiner then concluded that Terepin teaches the third missing element, determining that Terrapin shows the use of an analog-to-digital convertor capable of converting analog signals to digital bit patterns. Based on these conclusions, the examiner rejected the claims.
The Board affirmed the examiner’s rejection of the claims, finding “that an ordinarily skilled artisan . . . would have recognized that substituting Das’s wired crossbar array for Falk’s optical path crossbar would have predictably yielded Mouttet’s claimed computing device.” The Board also found that using electronic hardware instead of optical hardware would not detroy Falk’s operability as a programmable arithmetic unit, that Falk does not teach away from electrical circuitry, and that there were adequate reasons to combine the prior art references. In so finding, the Board noted, “there is no requirement that the examiner show how to physically incorporate Das’s features into Falk. . . .” The Applicant then appealed the Board’s decision to the Federal Circuit.
On appeal, the Applicant argued (1) that substituting electronic hardware for optical hardware would destroy the Falk device’s principle of operation, and physical structure, and (2) that Falk teaches away from the claimed invention. With regard to the first argument, the Federal Circuit concluded “the examiner saw nothing in the programming and processing of junction states in Falk that is unique to its optical implementation, and Mouttet has not shown otherwise. . . . [T]he difference in the circuitry – electrical versus optical – does not affect the overall principle of operation of a programmable arithmetic processor was supported by substantial evidence.” With regard to the second argument, the Federal Circuit found that the Applicant failed to cite any reference suggesting that the crossbar arithmetic processor described in Falk “should not” or “cannot” be implemented with electrical circuitry. Based on these findings, the Federal Circuit upheld the Board’s and the examiner’s denial of Applicant’s claims.