In Slot Speaker Techs., Inc. v. Apple Inc., Nos. 2015-2038, 2015-2039 (Fed. Cir. February 17, 2017) (non-prec.), the Federal Circuit affirmed a portion of the PTAB’s decision in an IPR that concluded claims 1 and 2 of U.S. Patent No. 7,433,483 would have been obvious over a combination of two prior art references, but reversed the portion that concluded that the same combination does not render dependent claim 3 obvious. The decision is interesting because the Board and the Federal Circuit concluded that the reduced effectiveness of the combined references as compared to a single reference alone would not deter a person of skill in the art from having a reasonable expectation of success in making the invention.

The ’483 patent is directed to a narrow profile sound system. A speaker unit with a narrow profile sound system, such as that claimed in the ’483 patent, can be placed in the dashboard of a vehicle and used as part of an automobile sound system . Claims 1 and 2 of the ’483 patent include limitations directed to “sound damping material forming sides of the sound duct,” while Claim 3 includes a limitation in which “sound damping material forms a back wall of a sound duct, said back wall substantially following a contour of a portion of the speaker cone farthest opposite the output slot.” The PTAB found that a prior art reference, Tomonori (EP 0744880 A1), disclosed every limitation of claims 1 and 2, except for the “sound damping material forming sides of the sound duct.” The PTAB found that a second prior art reference, Sadaie (WO Pub. No. 00/52958), disclosed the use of sound damping material along the sides of a sound duct and that a person of ordinary skill in the art would have been motivated to modify Tomonori by using the teachings of Sadaie.

On appeal, the Federal Circuit determined that the PTAB’s findings regarding Sadaie are supported by substantial evidence: the plain language of Sadaie, and by an implicit admission by the Patent Owner’s counsel at oral hearing that Sadaie taught sidewall-only placement of sound absorbing material. The court further determined that substantial evidence also supports the PTAB’s finding of a reason to combine Tomonori with Sadaie: Sadaie disclosed that the use of sound absorbing material was a known configuration to suppress unwanted soundwaves, and the Petitioner’s expert testified that side-wall only sound damping material would be a routine design choice as “one of a limited number of known solutions to minimize the presence of standing waves and other unwanted soundwaves inside the duct.” (p. 10, 15). Based on its conclusion that substantial evidence supported the PTAB’s fact finding, the court affirmed the PTAB’s determination that claim 1 would have been obvious. The court also affirmed the Board’s determination that claim 2 would have been obvious, but did so because the Patent Owner did not dispute the PTAB’s determination.

Claim 3 depends from claim 1, and, as previously mentioned, further specifies that the “sound damping material forms a back wall of a sound duct, said back wall substantially following a contour of a portion of the speaker cone farthest opposite the output slot.” The PTAB found that neither Tomonori nor Sadaie discloses this limitation. The PTAB focused its analysis on Figure 18 of Sadaie to come that conclusion with respect to Sadaie. The PTAB further found that the Petitioner’s expert failed to explain why a person of ordinary skill in the art would have relied on Sadaie’s disclosure of a preferred embodiment to modify the shape of the sound damping material by following the curved contour of a speaker cone, as recited in claim 3.

On appeal, the Federal Circuit determined that the claim language “substantially following a curved contour” of claim 3 did not require the back wall of Sadaie to follow the entire contour of the speaker cone. The court thus determined that Sadaie expressly disclosed embodiments in figures other than Figure 18, where the back wall substantially followed the curve the speaker cone. The court relied on common sense, as well as expert testimony, to conclude there exists a sufficient teaching to modify Tomonori’s straight back wall to the curved shape described in Sadaie, noting “[w]hile we do not rely on common sense lightly, where, as where, the only evidence of record supports the conclusion that the modification at issue is readily within the ken of those skilled in the art, it is appropriate to do so.” (p. 19).

This case is a useful reminder to practitioners attempting to overcome obviousness rejections or invalidity assertions that “[t]he relevant inquiry is whether a person of ordinary skill in the art would have a reasonable expectation of success” and that “[i]t is irrelevant whether [the references] together would be less effective than [one reference] alone.” (p. 14). Here, the PTAB and the court rejected the Patent Owner’s argument that Tomonori and Sadaie should not be combined because Sadaie focused on the production of low frequency bass sounds as opposed to the production of full-range sound, noting that the claims did not “require absorption of specific resonances at specific frequencies, nor any specific threshold with respect to signal loss.” (p. 14). In support, the court cited In re Kahn, 441 F.3d 977, 990 (Fed. Cir. 2006), which likewise dismissed the idea that references could not be combined merely because the combination would be less effective.