In two related inter partes review final written decisions, the PTAB relied on extrinsic evidence to invalidate patent claims. In Mobotix Corp. v. e-Watch, Inc., Petitioner Mobotix Corp. challenged the validity Patent Owner E-Watch, Inc.’s U.S. patents 7,023,913 and 7,733,371, related to digital security multimedia sensors. (Cases IPR2013-00334, Paper No. 5; IPR2013-00337, Paper No. 5) The Petitioner asserted that the claims of the challenged patents were unpatentable as obvious over various combinations of prior art references. (Id. at p. 3) The PTAB granted institution of the IPRs based on most of the Petitioner’s asserted grounds of unpatentability and ultimately found the challenged claims unpatentable over the asserted prior art combinations. (Cases IPR2013-00334, Paper No. 14 at p. 24; IPR2013-00337, Paper No. 12 at pp. 29-30).
In its revised petition for institution, the Petitioner proposed construction of the term “compressor” as “a device for reducing the number of bits needed to represent an item of digital data,” citing Computer User’s Dictionary, Microsoft Press, p. 76 (1998). The Petitioner also proposed that the term “multiplexer” should be construed as “a device for combining two or more input signals into at least one output signal,” citing McGraw-Hill Dictionary of Scientific Technical Terms, Fifth Ed., p. 1309 (1994). (Cases IPR2013-00334, Paper No. 5 at p. 4; IPR2013-00337, Paper No. 5 at p. 4).
E-Watch argued in its Patent Owner Response that the Petitioner’s proposed constructions of both “compressor” (Case Nos. IPR2013-00334, Paper No. 25 at pp. 5-7; IPR2013-00337, Paper No. 28 at pp. 8-9) and “multiplexor” were overly narrow, as the proposed constructions excluded software implementations of compressors and multiplexers, which were not excluded by the corresponding patent specifications. The Patent Owner asserted that neither term required construction, but that if construed, the term “compressor” should be construed as “hardware, software, or a combination for performing data compression,” and that the term “multiplexer” should be construed as “hardware, software, or a combination for performing data multiplexing.” (Cases IPR2013-00334, Paper No. 28 at p. 9; IPR2013-00337, Paper No. 25 at pp. 5-7). The Patent Owner further argued that a person having ordinary skill in the art would not construe the terms “compressor” or “multiplexer” to exclude software implementations. In support of its contentions, the Patent Owner relied upon an expert declaration which cited to software implementations of compressors and multiplexers. In rebuttal, the Petitioner argued that the specifications of the challenged patents did not enable software implementations of the “compressor” and “multiplexer.” Rather, the Petitioner cited specific examples of circuitry and hardware implementations corresponding to the disputed terms (e.g., “permitting all of the sensors to communicate directly to a single processor, compressor, transmitter circuit” (emphasis original)). (Cases IPR2013-00334, Paper No. 34 at p. 10; IPR2013-00337, Paper No. 27 at p. 13).
The board ultimately agreed with the Petitioner in its Final Written Decision, finding that the Petitioner’s extrinsic definitions of “compressor” and “multiplexer” are consistent with the specifications of the challenged patents. (Cases IPR2013-00334, Paper No. 39 at p. 8; IPR2013-00337, Paper No. 35 at p. 7) Further, the board noted that “[a]lthough Patent Owner asserts that the Specification does not expressly exclude software-based compressors, the fact that the Specification does not exclude a particular implementation does not indicate that it includes it.” Id. Instead, the board stated that the proper inquiry relates to the understanding of one having ordinary skill in the art as to whether the broadest reasonable interpretation of the disputed terms would include “disembodied software implementations.” Id. Further, the board noted that the purported extrinsic software implementations cited by the Patent Owner’s expert appear to discuss implementation on processor hardware, consistent with the Petitioner’s proposed construction.
One important takeaway from these decisions is that the board does not appear to be reluctant to accept extrinsic definitions in claim construction, so long as the extrinsic definitions comport with the challenged patent’s specification. Although not entirely inconsistent with existing litigation practice, this position would seem to provide increased weight to extrinsic evidence in claim construction at the PTAB (e.g., extrinsic evidence may form the basis of claim construction so long as it does not contradict the intrinsic record). Furthermore, the board’s reliance on extrinsic evidence raises questions regarding the notice function of claims. For example, if a claim is construed according to evidence not included in the intrinsic record, the metes and bounds of the claims may not adequately serve the claim’s intended notice function. In contrast, the claim’s notice function would be satisfied if an extrinsic definition is relied upon by the board to confirm an interpretation grounded in the intrinsic record (e.g., if a claim term is amenable to multiple interpretations, extrinsic evidence may be used to clarify the proper understanding of one having ordinary skill in the art).
For the time being, both Petitioners and Patent Owners should take note that, during claim construction in post grant proceedings, the PTAB tends to rely on extrinsic evidence, so long as the extrinsic evidence does not explicitly contradict the intrinsic record. This is true despite the board’s apparent narrowing of the broadest reasonable interpretation as it relates to non-excluded embodiments in a challenged patent’s specification.