Last Month at the Federal Circuit
Last Month at the Federal Circuit

June 2012

Obviousness Combination Does Not Impermissibly Change Operating Principle of Prior Art

Judges:  Prost, O’Malley, Reyna (author)
[Appealed from Board]

In In re Mouttet, No. 11-1451 (Fed. Cir. June 26, 2012), the Federal Circuit affirmed the rejection of all pending patent claims in U.S. Patent Application No. 11/395,232 (“the ’232 application”) for obviousness under 35 U.S.C. § 103.  The Court upheld the Board’s factual findings that a person of ordinary skill in the art would predictably combine the prior art to yield the claimed subject matter and that the prior art did not teach away from the claimed invention.

Sole inventor Blaise Laurent Mouttet submitted the ’232 application disclosing a nanoscale “Crossbar Arithmetic Processor.”  The ’232 application claims a nanoscale array of conductive parallel wires laid in columns on top of a second set of conductive wires in rows, where a thin film joins the crosspoints.  The device stores binary values by applying varying voltages across the wires and changing the crosspoint film’s resistance.  The ’232 application also discloses an input unit that controls the voltages and an output unit that reads and converts the analog voltages into digital outputs. 

At the PTO, the examiner rejected the claims of the ’232 application as obvious under 35 U.S.C. § 103.  The examiner considered, inter alia, three pieces of prior art:  a patent disclosing an optical crossbar arithmetic processor (“Falk”); a publication describing an electrical nanoprocessor system integrated on the molecular scale (“Das”); and a patent disclosing a digital signal processor (“Terepin”). 

Mouttet appealed to the Board, which affirmed the rejection of all claims.  The Board explained that the Falk reference discloses all but three limitations of the ’232 application.  Specifically, the Falk reference discloses optical paths instead of electrical wires, crosspoints with programmable optical intensity rather than electrical conductivity, and no analog-to-digital converter.  In other words, although both Falk and Mouttet disclose crossbar arithmetic units, the Board determined that the Falk reference teaches the use of optical techniques for data transmission and storage while the Mouttet reference uses electrical techniques.  After examining the references, the Board ruled that one of ordinary skill in the art would have substituted Das’s electrically wired array for Falk’s optical crossbar.  Combined with the analog-to-digital converter from Terepin, the Board concluded that these three pieces of prior art yielded Mouttet’s claimed device.

The Board also found that the prior art did not teach away from the device claimed in the ’232 application because, to teach away, a reference must discourage one of ordinary skill in the art from pursuing an area of design.  The Board found that language in Falk describing the “fundamental difference” between optical and electrical circuits represents a preferred embodiment rather than a teaching away.

“It is well-established that a determination of obviousness based on teachings from multiple references does not require an actual, physical substitution of elements.”  Slip op. at 15.

Mouttet then appealed to the Federal Circuit, again arguing that substituting electronic hardware for optical hardware would destroy the Falk device’s principle of operation and physical structure, and that Falk teaches away from the clamed invention.

The Federal Circuit first considered Mouttet’s argument that the Board erred in finding that Falk does not suggest that using electronic wires instead of optical paths would destroy Falk’s ability to operate as a programmable arithmetic unit.  Explaining that nothing in Falk’s disclosure applies uniquely to optical implementation, the Court concluded that a person of ordinary skill in the art would have recognized the structures’ functional equivalence, even in the absence of full physical equivalence.  The Court explained that “[i]t is well-established that a determination of obviousness based on teachings from multiple references does not require an actual, physical substitution of elements.”  Slip op. at 15.  Accordingly, the Board’s § 103(a) determination did not require that Das’s features be deemed equivalent for purposes of substitution into Falk’s device.  The Court concluded that the Board properly found that Falk’s arithmetic processor could have been combined with Das’s wired crossbar array to predictably yield Mouttet’s claimed computing device. 

The Court also considered Mouttet’s objection to the substitution of electrical components into Falk’s optical crossbar array where the Board designated Falk the “base reference.”  The Court concluded that Mouttet’s objection was based on the incorrect assumption that, because Falk was designated as the primary reference, Falk’s optically based crossbar implementation was a controlling principle of operation that any prior art combination must preserve.  The Court noted that “where the relevant factual inquiries . . . are otherwise clear, characterization by the examiner of prior art as ‘primary’ and ‘secondary’ is merely a matter of representation with no legal significance.”  Id. at 16.

The Federal Circuit next considered Mouttet’s argument that Falk teaches away from the clamed invention.  The Court, however, found substantial evidence to support the Board’s determination that the passage in Falk on which Mouttet relied does not teach away from a computing device using an electrical crossbar array.  The Court reminded that the “mere disclosure of alternative designs does not teach away,” and that “just because better alternatives exist in the prior art does not mean that an inferior combination is inapt for obviousness purposes.”  Id. at 18 (quoting In re Fulton, 391 F.3d 1195, 1201 (Fed. Cir. 2004)).  Finding no teaching in Falk that a crossbar arithmetic processor should not or cannot be implemented with electronic circuitry, the Federal Circuit upheld the Board’s determination that Falk does not teach away from the claimed invention.

*Benjamin T. Sirolly is a Summer Associate at Finnegan.