PTAB

IPR2018-00179

IEE Sensing, Inc. v. Delphi Technologies, Inc.

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1. Case Identification

2. Patent Overview

  • Title: Occupant Detection System with Common Mode Choke Isolation
  • Brief Description: The ’194 patent discloses an occupant detection system for a vehicle seat where a heating element is used for both seat heating and capacitive occupant sensing. The invention’s purported improvement is the use of an isolation circuit, specifically employing a common mode choke, to electrically isolate the occupant detection circuit from the heating circuit to prevent electrical interference.

3. Grounds for Unpatentability

Ground 1: Claims 1-8 are obvious over Nix

  • Prior Art Relied Upon: Nix (Application # 2008/0186282).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Nix discloses every element of the challenged claims. Nix describes a system for controlling vehicle equipment that detects an operator's presence in a seat, which functions as the claimed "occupant detection system." Nix teaches using a conductive surface, which can be a seat heating mat, for capacitive coupling with the operator. This mat includes a resistive heating element (limitation 1.2) connected to a heating circuit (1.4, 1.5). Crucially, Nix discloses an occupant detection circuit (signal generator 518 and associated logic) that is electrically coupled to this heating mat (1.6). To solve the problem of the low-resistance heating circuit interfering with the high-frequency detection signal, Nix explicitly teaches interposing an isolation circuit comprising a "common mode rejection choke" (514) between the heating circuit and the heating element (1.8, 1.9).
    • Motivation to Combine (for §103 grounds): This ground is based on a single reference. Petitioner asserted that limitations in dependent claims regarding the specific configuration of the common mode choke (e.g., being a four-terminal device, inductively coupling a first and second inductor) are inherent and obvious properties of the standard common mode choke explicitly disclosed by Nix. A person of ordinary skill in the art (POSITA) would have recognized Nix's choke as having these fundamental characteristics.
    • Expectation of Success (for §103 grounds): Not applicable for a single-reference ground, but the expectation of achieving the claimed functionality was inherent in Nix's own disclosure, which teaches using the choke to achieve the desired isolation.

Ground 2: Claims 1-8 are obvious over Kincaid in view of Nix

  • Prior Art Relied Upon: Kincaid (Application # 2009/0295199) and Nix (Application # 2008/0186282).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner contended that Kincaid discloses a system nearly identical to the ’194 patent, including an occupant detection system, a seat assembly with a heating element, a heating circuit, and an occupant detection circuit. Kincaid addresses the same problem of isolating the heating and detection circuits. However, Kincaid's isolation circuit uses active components rather than a passive common mode choke. Nix remedies this single deficiency by teaching the use of a common mode choke as an isolation circuit for the express purpose of preventing a low-resistance heating circuit from interfering with an occupant detection signal in a vehicle seat.
    • Motivation to Combine (for §103 grounds): A POSITA, aware of the shared problem of circuit interference addressed by both Kincaid and Nix, would have been motivated to substitute the known isolation circuit from Nix (a common mode choke) into the nearly identical system of Kincaid. This substitution would be a predictable design choice to achieve the improved isolation and reduced interference explicitly taught by Nix, thus arriving at the invention claimed in the ’194 patent. The combination was presented as a simple substitution of one known element for another to obtain predictable results.
    • Expectation of Success (for §103 grounds): A POSITA would have had a high expectation of success because Nix teaches that its common mode choke-based isolation circuit successfully solves the exact problem of signal interference that exists in a system like Kincaid's.

4. Key Claim Construction Positions

  • Common Mode Choke: Petitioner proposed this term be construed as "A four-terminal inductor consisting of two inductors created by two windings on a single core with the windings wound such that common-mode currents flowing in the same direction through each of the choke windings create equal and in-phase magnetic fields of the same polarity which add together." This construction was critical to the argument that claimed features, such as being a four-terminal device and having inductively coupled windings that induce current, are inherent and obvious properties of any standard common mode choke, like the one disclosed in Nix.

5. Relief Requested

  • Petitioner requested the institution of an inter partes review and the cancellation of claims 1-8 of the ’194 patent as unpatentable under 35 U.S.C. §103.