PTAB

IPR2017-01926

GN Hearing A/S v. Oticon A/S

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1. Case Identification

2. Patent Overview

  • Title: Audio Device Comprising a Microphone
  • Brief Description: The ’621 patent describes an audio device, such as a hearing aid, with specially designed sound inlets to reduce wind noise. The invention claims the use of slit-formed openings in a protective screen where the external-facing surface of the opening is rounded, and the internal-facing edge is sharp. This configuration is intended to reduce air turbulence while the sharp edge helps prevent moisture from entering.

3. Grounds for Unpatentability

Ground 1: Obviousness over Saltykov and Dodge - Claims 1-10 are obvious over Saltykov in view of Dodge.

  • Prior Art Relied Upon: Saltykov (Patent 7,245,733) and Dodge (Patent 1,664,852).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Saltykov disclosed a hearing aid with a protective faceplate and sound port covers designed to reduce wind noise for its directional microphones. However, Saltykov’s openings were depicted as simple holes. Dodge, an earlier patent for a telephone mouthpiece, was cited for its explicit teaching of using slit-formed openings with a smooth, curved outer surface and a sharp inner edge specifically to minimize "windage effects." Petitioner asserted that Dodge’s slit design directly corresponds to the key limitations of the ’621 patent’s claims.
    • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA) would combine these references because both addressed the common problem of microphone noise in audio devices. Saltykov identified wind noise as a particular issue for its directional microphones. A POSITA would look to known solutions and find Dodge’s teaching of using contoured, slit-formed openings as a well-documented method for reducing such noise. The motivation was to improve the wind-noise performance of Saltykov’s hearing aid by substituting its basic openings with the more advanced, purpose-built slit design from Dodge.
    • Expectation of Success: A POSITA would have a high expectation of success because the combination involved applying a known noise-reduction technique (Dodge's slits) to a known problem (Saltykov's wind noise) in the analogous field of audio-capture devices. The principles of acoustics and fluid dynamics governing wind noise are the same for a telephone mouthpiece and a hearing aid inlet.

Ground 2: Obviousness over Sjursen and Mundel - Claims 1-2, 4-6, and 9 are obvious over Sjursen in view of Mundel.

  • Prior Art Relied Upon: Sjursen (WO 00/41432) and Mundel (a 1947 journal article titled Broadened Criteria of Hearing Aid Performance).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner contended that Sjursen disclosed a disposable hearing aid with inlet holes and taught that "flaring the outside and/or inside surfaces" helps reduce wind-induced noise. While Sjursen taught the benefit of curved openings, it did not specify a slit shape, noting the openings could be of "any convenient shape." Mundel, which specifically focused on hearing aid performance, was introduced for its teaching of a recessed grille with slit-formed openings and rounded outer edges to reduce noise. Petitioner mapped Mundel’s recessed, slit-shaped grille with rounded edges directly onto the core limitations of the challenged claims.
    • Motivation to Combine: The motivation to combine was direct and strong. Since Sjursen explicitly left the shape of its noise-reducing openings open to any "convenient shape," a POSITA seeking to optimize the design would naturally incorporate the slit-formed, rounded-edge grille from Mundel. Both references were directly concerned with improving hearing aid acoustics, making the combination a straightforward design choice to achieve superior noise reduction.
    • Expectation of Success: Success would be predictable, as the combination merely involved selecting a specific, advantageous shape (Mundel's slits) for a component that Sjursen already described as having a variable shape. The underlying principle—using rounded edges to reduce turbulence—was taught by both references.

Ground 3: Obviousness over Sjursen, Mundel, and Saltykov/Dodge - Claims 3, 7, 8, and 10 are obvious over combinations of the primary references.

  • Prior Art Relied Upon: Sjursen (WO 00/41432), Mundel (1947 journal article), Saltykov (Patent 7,245,733), and Dodge (Patent 1,664,852).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground asserted that the remaining dependent claims were obvious by further combining the base references. Saltykov was added to the Sjursen/Mundel combination to supply the teaching of a directional microphone system with two spatially separated canals and a specific inter-opening distance (addressing claims 3, 7, and 8). Dodge was added to the Sjursen/Mundel combination to provide the explicit teaching of a "sharp" edge having a maximum radius of curvature of 0.05 mm (addressing claim 10).
    • Motivation to Combine: A POSITA would be motivated to add Saltykov’s directional microphone configuration to the Sjursen/Mundel hearing aid to provide directional capability, a well-known and desirable feature. To satisfy the specific dimensions of claim 10, a POSITA would find it obvious to optimize the sharpness of the inner edge as taught by Dodge, which disclosed various degrees of sharpness. This was presented as routine design optimization.

4. Key Claim Construction Positions

  • "Slit-formed opening": Petitioner proposed this term be construed as "an opening formed as a slit," referencing a dictionary definition of slit as a "long, narrow opening or crack." This construction was central to arguing that prior art like Dodge and Mundel, which show long, narrow grille openings, met this limitation.
  • "Sharp edge": Petitioner argued this term rendered claims 1-9 indefinite. However, for the purposes of the IPR, Petitioner proposed it should be interpreted in contrast to the claimed "smooth and gradual curve" to mean "the meeting of two surfaces that is not a smooth, gradual curve." This construction was used to show that the distinct, non-rounded inner edges in Dodge and Mundel satisfied the claim limitation. For claim 10, the specific "maximum radius of curvature of 0.05 mm" was argued to be an obvious design choice for achieving a sufficiently sharp edge.

5. Relief Requested

  • Petitioner requested institution of an inter partes review and cancellation of claims 1-10 of the ’621 patent as unpatentable.