PTAB

IPR2017-01700

LG Electronics Inc v. Lemaire Illumination Technologies LLC

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Petition
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1. Case Identification

2. Patent Overview

  • Title: Method and Apparatus for an L.E.D. Flashlight
  • Brief Description: The ’661 patent describes an illumination source, such as an LED flashlight, that uses a control circuit to maintain a constant light output level even as the battery voltage declines. The circuit employs pulsed power, such as pulse width modulation (PWM), and can also adjust the light's color spectrum.

3. Grounds for Unpatentability

Ground 1: Obviousness over Van Antwerp, Bosch, and Basrur - Claims 34 and 36 are obvious over Van Antwerp in view of Bosch and in further view of Basrur.

  • Prior Art Relied Upon: Van Antwerp (Patent 4,514,727), Bosch (Patent 5,373,387), and Basrur (Appl. Phys. Lett. 71(10), 8 September 1997).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Van Antwerp disclosed the core limitations of claim 34: an illumination source with an LED housing and a control circuit that applies pulsed power to maintain a predetermined light output level as the DC voltage source varies. Specifically, Van Antwerp taught using PWM to hold the brightness of an LED display constant as battery voltage drops. To address the additional limitation of controlling the light’s color spectrum, Petitioner asserted that the combination of Bosch and Basrur rendered this feature obvious. Bosch taught a control circuit for a laser diode—argued to be analogous to an LED—that used both PWM and pulse amplitude control to manage both average light output and light amplitude. Basrur then explicitly taught that the color spectrum of an LED (specifically, a Gallium Nitride blue LED) could be shifted to ultraviolet by controlling the amplitude and duration of the current pulses.
    • Motivation to Combine: Petitioner contended that a person of ordinary skill in the art (POSITA) seeking to create a stable illumination source would have been motivated to combine these references. A POSITA starting with Van Antwerp’s constant-brightness circuit would recognize that varying voltage also affects color spectrum, a known problem. To solve this, the POSITA would look to analogous arts, like the laser diode control taught in Bosch, for methods to control pulse amplitude. Finding that Bosch provides a dual-control (PWM and amplitude) circuit, and that Basrur explicitly teaches using pulse amplitude to control color in the specific type of LED mentioned in the ’661 patent, the combination would have been a logical path to achieving predictable control over both brightness and color.

Ground 2: Obviousness over Mallory/Garriss, Bosch, and Basrur - Claims 34 and 36 are obvious over Mallory and Garriss in view of Bosch and in further view of Basrur.

  • Prior Art Relied Upon: Mallory (Patent 4,499,525), Garriss (Patent 5,010,412), Bosch (Patent 5,373,387), and Basrur (Appl. Phys. Lett. 71(10), 8 September 1997).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground presented an alternative primary combination to arrive at a constant-brightness LED flashlight. Petitioner argued that Mallory disclosed a flashlight for an incandescent bulb that used a PWM circuit to elongate power pulses as battery voltage dropped, thereby maintaining constant illumination. Garriss disclosed a portable illumination source using an array of LEDs powered by a PWM circuit. Petitioner contended that combining Mallory and Garriss taught the constant-brightness LED source of claim 34. The motivation to add control over the color spectrum by combining this base with Bosch and Basrur followed the same logic as in Ground 1.
    • Motivation to Combine: Petitioner asserted that a POSITA would have been motivated to combine Mallory and Garriss to improve upon existing technology. A POSITA would have recognized the efficiency benefits of the LEDs in Garriss and sought to incorporate them into the superior constant-illumination circuit of Mallory, simply replacing the outdated incandescent bulb. The combination was presented as a predictable assembly of known components. Once this improved constant-brightness LED flashlight was conceived, the motivation to add the color control teachings of Bosch and Basrur would arise for the same reasons articulated in Ground 1: to solve the known problem of color shift and gain full control over the light output.

4. Key Claim Construction Positions

  • "Maintain a Predetermined Light Output Level": Petitioner adopted the construction from a prior IPR for the ’661 patent, defining this phrase as "to keep the light output level in a state of the light output level settled in advance." This construction was central to mapping the PWM teachings of Van Antwerp and Mallory, which were designed to achieve this exact outcome.
  • "Characteristic color spectrum": For claim 36, Petitioner argued this term should be construed as "the selected color spectrum." This was based on the patent’s specification, which differentiates between LEDs with a "first" and "second" characteristic color spectrum. This construction supported the argument that Basrur’s teaching of selecting different color spectra by varying current directly met the claim limitation.

5. Key Technical Contentions (Beyond Claim Construction)

  • Analogy Between Laser Diodes and LEDs: A central technical contention was that a POSITA would have considered control circuitry for laser diodes, as taught in Bosch, to be directly analogous and readily adaptable for use with LEDs. Petitioner argued that both are p-n junction semiconductor devices with similar electrical properties, and it was routine in the art to adapt circuit designs between them. This analogy was critical for importing Bosch’s teaching of pulse amplitude control as a solution for controlling the color spectrum of LEDs.

6. Relief Requested

  • Petitioner requested institution of an inter partes review and cancellation of claims 34 and 36 of the ’661 patent as unpatentable.