PTAB

IPR2014-00959

LG Electronics Inc v. NFC Technology LLC

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Petition
petition Intelligence

1. Case Identification

2. Patent Overview

  • Title: Antenna Signal Amplitude Modulation Method
  • Brief Description: The ’551 patent relates to a contactless communication device, such as an RFID reader, designed to be compatible with multiple modulation standards. The invention describes a method of modulating the amplitude of an antenna signal by using a control circuit (e.g., a microprocessor) with multiple binary ports that can be individually set to a high-impedance state, thereby varying the aggregate power supplied to the antenna circuit.

3. Grounds for Unpatentability

Ground 1: Anticipation of Claims 1-3 and 5 under 35 U.S.C. §102 by Sears

  • Prior Art Relied Upon: Sears (Patent 6,122,492).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Sears, which discloses an adjustable radio frequency (RF) power amplifier for an RFID system, anticipates every limitation of the challenged claims. Sears teaches modulating an antenna signal's amplitude by varying the number of active parallel buffers driving the antenna. Petitioner contended that these "tristatable" buffers, which can be set to a high level, a low level, or be completely disconnected, are equivalent to the ’551 patent’s "binary ports that can be set to high impedance state." Sears achieves full power (the "1" state) when all buffers are active and providing high-level output. It achieves 100% modulation (the "0" state) when the active buffers provide a low-level (zero volt) output. Finally, it achieves partial modulation of less than 100% by setting at least one buffer to a high-impedance (disconnected) state while others remain active, which Petitioner argued meets the limitations of claim 3.

Ground 2: Anticipation of Claims 1-3 and 5 under 35 U.S.C. §102 by Downs

  • Prior Art Relied Upon: Downs (Patent 5,926,110).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner asserted that Downs, which teaches a programmable output device for an RF/ID transponder, anticipates the challenged claims. Downs modulates signal amplitude by using a series of resistors, each of which can be selectively shorted out by a corresponding transistor switch (a "pass gate"). Petitioner argued that each resistor-switch pair constitutes a claimed "port." The ports have two states: a high-impedance state (switch open, resistor in-circuit) and a low-impedance state (switch closed, resistor shorted). By digitally controlling these switches, Downs varies the total resistance and thus modulates the antenna current. Petitioner contended that setting all switches to the closed state (shorting all resistors) corresponds to the "1" state for full power. Conversely, setting all switches to the open state ("0" state) maximizes resistance to achieve 100% modulation. Partial modulation is achieved by shorting some resistors while leaving others in the circuit.

Ground 3: Obviousness of Claims 1-3 and 5 under 35 U.S.C. §103 over Asakura and Carroll

  • Prior Art Relied Upon: Asakura (Patent 5,835,010) and Carroll (Patent 5,347,263).

  • Core Argument for this Ground:

    • Prior Art Mapping: Asakura taught an RFID system that used a discrete driving circuit with parallel transistors and different-valued series resistors to create multiple distinct modulation levels. Carroll taught a more compact and efficient RFID system that used a single microcontroller with multiple parallel-connected I/O ports to drive an antenna directly, eliminating the need for a separate driver circuit. Petitioner noted that the datasheet for the microcontroller used in Carroll (the PIC16C5x series) explicitly disclosed that its I/O ports could be individually programmed to a high-impedance state to disconnect them from the circuit.
    • Motivation to Combine: A POSITA would combine Carroll’s compact microcontroller-based driver with Asakura’s system to gain the benefits of reduced component count, lower cost, and smaller size. To achieve the multi-level modulation taught by Asakura, the POSITA would look to the capabilities of Carroll’s microcontroller.
    • Expectation of Success: A POSITA would have had a high expectation of success in implementing Asakura's modulation scheme using Carroll's technology. It would have been a straightforward design choice to use the documented high-impedance feature of Carroll's I/O ports to selectively enable or disable individual ports. This technique of varying the number of active parallel drivers was a known and simple equivalent to Asakura's method of using different resistor values to achieve different power levels.

  • Additional Grounds: Petitioner asserted an additional obviousness challenge against claims 1-3 and 5 over Sears in view of Nguyen (Patent 5,399,925). This ground argued that to the extent Sears’s disclosure of a "tristate" buffer was considered deficient, Nguyen explicitly taught a tristatable buffer that could be set to a "1," "0," or high-impedance state, making the combination obvious.

4. Key Claim Construction Positions

  • "binary port that can be set to high impedance state": Petitioner argued this term should be construed to mean a portion of a circuit capable of being set to binary logic "1," binary logic "0," or a high-impedance state. This construction was based on the ’551 patent’s own description and figures, which show ports (P1-P4) that can be set to these three distinct states to achieve different levels of modulation.
  • "high impedance state": Petitioner proposed that this term should be broadly construed to include any condition where a port is disconnected or in an open-circuit state, effectively removing its contribution from the antenna supply circuit. This was argued to be consistent with a POSITA's understanding and the patent's disclosure that ports are "disconnected" when set to this state.

5. Relief Requested

  • Petitioner requests institution of an inter partes review (IPR) and cancellation of claims 1-3 and 5 of the ’551 patent as unpatentable on all asserted grounds.