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Shure, Inc. v. Clearone, Inc.

United States District Court, N.D. Illinois, Eastern Division

August 25, 2019

SHURE, INC., Plaintiff, Counter-Defendant,
CLEARONE, INC., Defendant / Counter-Plaintiff.


          Honorable Edmond E. Chang, United States District Judge.

         ClearOne alleges that Shure's MXA910 audio-conferencing product infringes, among other patents, U.S. Patent No. 9, 635, 186. In March 2018, ClearOne lost its motion to preliminarily enjoin Shure's sales of the MXA910. R. 278, Memo Op. and Order.[1] The key flaw in ClearOne's motion was that, in the Court's view, Shure had raised a substantial question on the patent's validity. Id. at 27-37. Then, in January 2019, the Patent Trial and Appeal Board (PTAB) issued a final decision specifically holding that one of the same prior-art references on which this Court denied the preliminary injunction did not invalidate a related ClearOne patent, U.S. Patent No. 9, 264, 553. R. 478-1, PTAB Final IPR Decision at 19-29. ClearOne now moves for reconsideration of the preliminary-injunction denial in light of the PTAB's January 2019 decision. R. 481, Mot. Reconsider. For the reasons explained below, the motion to reconsider is denied. This Opinion assumes familiarity with the Court's previous preliminary injunction decision on the '186 Patent, R. 278.

         I. Background

         A. '186 Patent

         The core contribution of the U.S. Patent No. 9, 635, 186 (the '186 Patent) is a method of efficiently combining beamforming (a technology that combines signals from multiple microphones to generate a combined audio signal that picks up sounds from a particular location) with acoustic echo cancellation (known the industry as AEC), which is a technology that removes far-end echo from an audio-conferencing system. Memo Op. and Order at 3. The Court previously described the '186 Patent in its preliminary-injunction decision:

Figuring out how to combine beamforming and acoustic echo cancellation in a cost-efficient way-while still preserving audio quality-has been a longstanding challenge in the audio industry. …The illustrative claim of the '186 patent (Claim 7) discloses an efficient method of combining a beamforming microphone with AEC. The claimed method reduces AEC processing costs by providing a beamformer capable of picking up a number of audio signals, which are then combined into a smaller number of “fixed” beams. AEC is then performed on only the smaller number of fixed beams. Performing AEC on fixed (as opposed to adjustable) beams reduces the amount of work for the acoustic echo cancellers, which would otherwise need to constantly adjust to track the changing beams. After AEC is performed, a “signal selection module” selects one or more of the echo-cancelled signals to transmit to the far end. The signal selection module also uses the far-end signal as information to inhibit the change of the near-end signal selection while only the far-end signal is “active.”

Id. at 4 (internal citations omitted).

         B. Prior Decision

         In August 2017, ClearOne moved for a preliminary injunction to halt Shure's production and sale of the MXA910, a ceiling-mounted microphone that ClearOne alleges infringes the '186 Patent. R. 81, Mot. Prelim. Inj. The Court heard evidence on the motion in February 2018, and in March 2018 denied it. Memo Op. and Order. The Opinion found that ClearOne had met some of the requirements: ClearOne was likely to succeed in proving that Shure had infringed the '186 Patent and ClearOne would suffer (and had suffered) irreparable harm. Id. at 15-24. Also, most of Shure's invalidity arguments failed. Id. at 25-27. But the bad news for ClearOne was that two prior-art references likely made the '186 Patent obvious (and thus invalid). Id. at 27-36.

         First, the Court found that a 2001 book chapter authored by Dr. Walter Kellerman, called “Acoustic Echo Cancellation for Beamforming Microphone Arrays, ” created a substantial question on the patent's validity. See R. 158-2, Kellerman Decl. Exh. 2 (“Kellerman 2001”). Kellerman's chapter discloses a method of combining acoustic echo cancellation and beamforming that involves performing AEC “only on fixed (‘time-invariant') beams and then select[ing] which beam to transmit to the far end.” Memo Op. and Order at 28-29. Kellerman found that performing AEC only on fixed beams was more cost-effective than performing it on adaptive beams or on individual microphones before beamforming. Kellerman 2001 at 299. That is, “Kellerman saw the same problem as the '186 patent (the problem of efficiently combining AEC and beamforming) and arrived at the same solution (save on AEC costs by performing AEC on a smaller number of fixed beams.” Memo Op. and Order at 29. The Court noted that Kellerman 2001 did not disclose “last mic on”-the second contribution of the '186 Patent. Id. at 32. But the Court reasoned that because “[l]ast mic on was a well-known industry feature for decades before the publication of the Kellerman chapter or the issuance of the '186 patent, ” it would have been obvious to combine that feature with the AEC method Kellerman proposed. Id. at 32-33.

         The second problematic piece of prior art was a 1997 article, also authored by Kellerman, entitled “Strategies for Combining Acoustic Echo Cancellation and Adaptive Beamforming Microphone Arrays” (Kellerman 1997). The Court held that Kellerman 1997 likely rendered the patent obvious for the same reasons that Kellerman 2001 did: both references disclosed the idea of “reducing processing costs by decomposing beamforming into ‘time-invariant' (fixed) and ‘time-variant' parts and then performing AEC only on the time-invariant part.” Memo Op. and Order at 35 at 35-36. The Court further noted that Kellerman 1997 might actually have anticipated the '186 Patent-as opposed to simply making it obvious-but declined to definitively determine whether Kellerman 1997 disclosed the last mic on feature. Id. at 36-37.

         C. PTAB Proceedings

         Shortly before the Court issued its preliminary-injunction decision on the '186 Patent, the Patent Trial and Appeal Board, which had initiated inter partes review of the '553 Patent, found a reasonable likelihood that Shure would prevail on its obviousness argument against the '553 Patent based on Kellerman 2001. See R. 244, Patel Exh. 35, PTAB Initial IPR Decision at 11-14. Relying in part on the PTAB's preliminary decision, the Court noted in its preliminary-injunction decision that “the PTAB's opinion on the '553 patent [was] persuasive authority” because the illustrative claim in the '553 Patent (Claim 1) was nearly identical to Claim 7 of the '186 Patent. Memo Op. and Order at 28.

         Since then, the PTAB has reversed its preliminary finding on the '553 Patent's validity. The PTAB's final decision held that Shure failed to establish that the representative claims of the '553 Patent were unpatentable. PTAB Final IPR Decision at 48. Specifically, the PTAB held that Shure did not prove by a ...

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