PTAB

IPR2018-01062

Lite-On Technology v. Darfon Electronics Corp.

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1. Case Identification

2. Patent Overview

  • Title: Illuminated Keyboard Switch Structure
  • Brief Description: The ’612 patent discloses an illuminated keyboard structure where the backlight device is positioned beneath the key switch’s foundation layer (the “seat”), rather than between the seat and the keycap as in conventional designs. Light from the backlight device illuminates the keycap through a hole in the seat. The patent was subject to an ex parte reexamination where the claims were amended to overcome prior art. Notably, independent claim 1 was amended to add the limitation requiring "a plurality of reflective portions are disposed underneath the cap and spaced apart from each other on the same plane," which became the central focus of the invalidity arguments in this inter partes review (IPR) petition.

3. Grounds for Unpatentability

Ground 1: Claims 1, 5, 9-12, 14, 15, 17, 18, 21, and 22 are obvious over Chou in view of Parker.

  • Prior Art Relied Upon: Chou (Patent 6,554,442) and Parker (Patent 5,895,115).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Chou teaches the fundamental structure of the challenged claims, including a key switch with a seat, membrane circuit board, connecting assembly, and cap, with a backlight device located beneath the seat. This alignment was confirmed by the PTO during a prior ex parte reexamination of the ’612 patent, which concluded Chou disclosed every limitation of the claims except the element added during that reexamination: "a plurality of reflective portions are disposed underneath the cap and spaced apart from each other on the same plane." Petitioner contended that Parker, a reference not previously considered by the PTO, remedies this specific deficiency. Parker was argued to teach a "light emitting panel assembly" for backlighting keypads that explicitly includes a "plurality of reflective portions"—described as a "pattern of light extracting deformities or disruptions"—that are spaced apart on the same plane and positioned "corresponding to the location of the control buttons."
    • Motivation to Combine: Petitioner asserted a Person of Ordinary Skill in the Art (POSA) would combine Chou and Parker for several reasons. First, both references operate in the same field of illuminating keyboards/keypads and address the identical problem of increasing key illumination to help users locate keys. Second, Parker provides an express rationale for the combination by teaching the use of its reflective portions to increase light intensity and control light output, directly aligning with the stated goals of Chou. Third, the petition framed the combination as a simple and predictable substitution of Chou's basic lighting panel with Parker's functionally equivalent but structurally improved panel to achieve a known, desirable result.
    • Expectation of Success: Petitioner argued a POSA would have had a clear expectation of success in combining the references, as it involved the routine substitution of one known type of lighting element for another to predictably enhance illumination performance.

Ground 2: Claims 1, 5, and 9 are obvious over Chou in view of Nousiainen.

  • Prior Art Relied Upon: Chou (Patent 6,554,442) and Nousiainen (Patent 6,874,926).
  • Core Argument for this Ground:
    • Prior Art Mapping: The argument structure mirrored that of Ground 1. Petitioner again relied on Chou to teach the foundational keyboard structure. The petition then argued that Nousiainen, another reference not previously considered by the PTO, supplies the single missing "plurality of reflective portions" element. Nousiainen was alleged to disclose a mobile terminal with a "light conduit" and "light guiding section" that uses multiple "reflection surfaces" spaced apart underneath key locations. These surfaces are explicitly oriented to "reflect[] portions of the received light toward to the key locations," thus providing the claimed functionality.
    • Motivation to Combine: The motivation to combine Chou and Nousiainen was presented as analogous to the motivation for combining Chou with Parker. A POSA would be motivated to combine the teachings because both references are in the field of key illumination and seek to improve light distribution. Nousiainen provides an improved method of directing light that would be a logical and advantageous modification to the keyboard structure in Chou to increase light intensity and distribution. The combination would be a predictable substitution of known components.
    • Expectation of Success: Petitioner asserted a POSA would have expected the combination to work as intended, given the compatible nature of the technologies and their shared purpose of improving backlight efficiency.

4. Arguments Regarding Discretionary Denial

  • Petitioner argued that institution is appropriate under 35 U.S.C. §325(d) and discretionary denial is unwarranted. Although the primary reference, Chou, was considered during a prior ex parte reexamination, the petition presented new combinations and arguments. The secondary references, Parker and Nousiainen, were never before the PTO. Critically, these new references were argued to teach the very limitation that the PTO found missing from Chou during the reexamination, making the current invalidity grounds substantively different from any previously considered by the Office.

5. Relief Requested

  • Petitioner requested that the Board institute an inter partes review and cancel claims 1, 5, 9-12, 14, 15, 17, 18, 21, and 22 of the ’612 patent as unpatentable.