Nintendo Co., Ltd. v. American GNC Corporation

1. Case Identification

• Case #: IPR2024-00667
• Patent #: Patent 6,508,122
• Filed: March 7, 2024
• Petitioner(s): Nintendo Co., Ltd., and Nintendo of America Inc.
• Patent Owner(s): American GNC Corporation
• Challenged Claims: 1 and 3

2. Patent Overview

• Title: Microelectromechanical System for Measuring Angular Rate
• Brief Description: The ’122 patent relates to a microelectromechanical system (MEMS) for measuring the angular rate of a carrier. The system uses an angular rate sensor unit, central circuitry, and a digital signal processing system to control the sensor's vibratory (dither) motion and to process signals resulting from Coriolis forces to determine the rate of rotation.

3. Grounds for Unpatentability

Ground 1: Obviousness over Fujiyoshi, Kumar, Cox, and Townsend - Claims 1 and 3 are obvious over Fujiyoshi in view of Kumar, Cox, and Townsend.

• Prior Art Relied Upon: Fujiyoshi (Patent 5,945,599), Kumar (Patent 5,604,311), Cox (Patent 3,838,346), and Townsend (WO 99/14,557).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Fujiyoshi, a MEMS angular rate sensor, discloses the core structure of claim 1, including an "angular rate sensor unit" with vibratory mass, circuitry for receiving dither driver and displacement restoring signals, and circuitry for outputting angle rate and dither motion signals. To the extent Fujiyoshi does not explicitly teach "capacitive pickoff excitation signals," Petitioner asserted this feature was taught by Kumar, a similar vibrating gyro system that details capacitive sensing. The central circuitry's outputting of "digital low frequency" signals was argued to be obvious by modifying Fujiyoshi's analog system with the digital control system of Townsend, which teaches digitizing sensor signals to improve performance. Finally, Cox was introduced to teach a "sample and hold circuit" incorporating a low-pass filter to ensure the signals from the Townsend-modified circuitry were "low frequency" by removing noise.
  • Motivation to Combine: A POSITA would combine the analogous art of Fujiyoshi and Kumar to implement a known capacitive sensing technique in a MEMS gyroscope. A POSITA would then be motivated to replace the resulting analog control circuitry with the digital system taught by Townsend to overcome the known drawbacks of analog systems, such as difficulty in calibration and noise susceptibility. The addition of Cox’s filtering technique was presented as a known method for further improving noise reduction and sensor performance, a common goal in the field.
  • Expectation of Success: The combination of these references involved applying known digital control strategies and filtering components to a conventional analog sensor architecture. Petitioner asserted this would have been a predictable implementation with a high expectation of success.

Ground 2: Obviousness over Mitamura and Townsend - Claims 1 and 3 are obvious over Mitamura and Townsend.

• Prior Art Relied Upon: Mitamura (Japanese Patent Application Publication No. 9[1997]-42973) and Townsend (WO 99/14,557).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner contended that Mitamura, a "compact and lightweight" angular velocity sensor, discloses all limitations of claim 1 in an analog embodiment. Mitamura teaches a MEMS sensor with a vibrating mass, control circuitry, and feedback loops that correspond to the claimed "angular rate sensor unit" receiving and outputting the required dither, displacement, and angle rate signals. Petitioner then argued it would have been obvious to implement Mitamura's arithmetic unit and control circuitry using a digital signal processing system as taught by Townsend. This modification would render the "low frequency inertial element displacement signals" digital, as required by the claim.
  • Motivation to Combine: A POSITA would combine the analogous arts of Mitamura and Townsend to improve upon Mitamura's analog design. Townsend explicitly discusses the advantages of digital systems over analog ones, including easier calibration, better noise rejection, and simpler integration. A POSITA would therefore have been motivated to replace Mitamura's analog control loops with Townsend's digital implementation to achieve these well-known benefits.
  • Expectation of Success: The proposed modification was characterized as the straightforward substitution of known analog control components with their well-understood digital counterparts (e.g., a digital processor, A/D converters, D/A converters). This process of digitizing a sensor's control system was a known design choice, leading to a predictable outcome and a high expectation of success.

4. Arguments Regarding Discretionary Denial

• Petitioner argued against discretionary denial under §314(a) and the Fintiv factors. It contended that the parallel district court litigation is in its early stages, with no claim construction rulings issued and a trial date set for May 19, 2025, allowing the IPR to conclude well before trial. Petitioner also submitted a Sotera stipulation, agreeing not to pursue in district court any invalidity grounds that were raised or reasonably could have been raised in the IPR, should the petition be instituted.

5. Relief Requested

• Petitioner requests institution of an inter partes review and cancellation of claims 1 and 3 of Patent 6,508,122 as unpatentable.