In re Mouttet

When a patent claims a structure already known, differing only in the substitution of one known element for another, it must do more than yield the predictable result of that substitution to avoid rejection for obviousness.

Opinion (Reyna): Mouttet had applied for a patent on a “Crossbar Arithmetic Processor,” which used a series of crossed nanowires to perform arithmetic computations. The Board of Patent Appeals rejected his application, finding all of his pending claims unpatentable in light of prior art, particularly a patent covering a similar crossbar circuit using optical circuitry to perform the same functions as his device (the Falk patent), and a patent covering the use of nanowires as electrical switches. The Board found that an electrical engineer would have recognized that nanowires could be substituted for the optical circuitry in the Falk patent to predictably yield the device claimed by Mouttet. On appeal, Mouttet argued that substitution of the nanowires for the optical circuitry destroyed the physical structure of the Falk patent, and that the substitution was not obvious as the Falk patent taught away from the use electrical circuitry. The Federal Circuit disagreed, noting that when a patent claims a structure already known, differing only in the substitution of one known element for another, it must do more than yield the predictable result. Agreeing with the Board that the Falk patent disclosed the structure found in Mouttet’s device, the court rejected Mouttet’s physical structure argument; and also found that while the patent expressed a preference for optical circuitry, that preference was not sufficient to discourage the use of electrical circuitry. Because those findings constituted substantial evidence in support of the Board’s decision, the court AFFIRMED the rejection of Mouttet’s application.