PTAB

IPR2025-01413

BOE Technology Group Co., Ltd. v. 138 East LCD Advancements Limited

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1. Case Identification

2. Patent Overview

  • Title: Flexible Substrate and Electro-Optical Device
  • Brief Description: The ’512 patent describes an electro-optical device, such as a liquid-crystal display, that uses an integrated circuit (IC) mounted on a flexible substrate. The invention includes an "inspection electrode" on the substrate, connected to the IC, which can selectively output signals for testing purposes via a switching section.

3. Grounds for Unpatentability

Ground 1: Claims 1-4, 6, and 8-11 are obvious over Saito and Her

  • Prior Art Relied Upon: Saito (Patent 6,300,997) and Her (Application # 2004/0183563).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Saito taught the fundamental physical structure of the claimed invention, including a flexible substrate (“film wiring board”) with an IC mounted on it, a plurality of lines, connection terminals, and inspection electrodes (“test pads”) for checking signal connectivity. However, Petitioner contended Saito lacked the claimed “switching section” for selectively enabling or disabling the output to these inspection electrodes. Her allegedly supplied this missing element by disclosing an IC with a “channel shifter” that acts as a switching section. This shifter, controlled by a test mode signal, selectively outputs signals to a dedicated test pin only when in "test mode," thereby switching the inspection output on and off.
    • Motivation to Combine: A POSITA would combine Her’s switching functionality with Saito’s physical architecture to improve inspection and testing efficiency. Saito’s always-on test pads could cause parasitic capacitance, signal integrity issues, or unnecessary power draw. Petitioner asserted that adding Her’s selective on/off control was a predictable solution to these known problems.
    • Expectation of Success: The combination involved applying a known electronic control technique (Her’s switching) to a known physical layout (Saito’s flexible substrate) to gain a predictable improvement in testability and performance. Both references are from the analogous field of testing ICs on flexible substrates for display drivers.

Ground 2: Claims 1-6 and 8 are obvious over Taguchi and Her

  • Prior Art Relied Upon: Taguchi (Application # 2004/0183985) and Her (Application # 2004/0183563).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground presented an alternative to Ground 1, using Taguchi as the primary reference. Petitioner argued Taguchi, like Saito, disclosed the core claimed structure: a flexible "insulation film substrate," an IC, patterned wires ("lines"), connection terminals, and an inspection electrode ("test pad"). Specifically, Taguchi taught that its test pad was an enlarged portion of a wire to facilitate contact with a test probe. As in Ground 1, Her was cited to provide the "switching section" that Taguchi lacked, enabling selective on/off control of the test signal output.
    • Motivation to Combine: A POSITA would be motivated to incorporate Her’s advanced testing circuitry (test-mode switching and composite signal generation) into Taguchi’s conventional driver IC layout. This would address the industry-wide problem of testing increasingly complex, high-pin-count ICs by simplifying the test procedure and reducing the required number of test pins, a problem Her was designed to solve.
    • Expectation of Success: The combination was presented as a straightforward integration of compatible technologies for driving and testing LCD panels, which would have yielded predictable results.

Ground 3: Claim 5 is obvious over Saito and Her, in further view of Taguchi

  • Prior Art Relied Upon: Saito (Patent 6,300,997), Her (Application # 2004/0183563), and Taguchi (Application # 2004/0183985).

  • Core Argument for this Ground:

    • Prior Art Mapping: This ground built upon the combination of Saito and Her to specifically address dependent claim 5, which required the inspection electrode to have a "width larger than the widths of the lines." Petitioner argued that while Saito's figures visually suggested wider test pads, Taguchi explicitly taught this feature. Taguchi stated that its "test pad 9 is formed to have a width greater than that of the patterned wire" to "facilitate easier contact with a test probe."
    • Motivation to Combine: A POSITA would adopt Taguchi’s explicit teaching of a widened inspection electrode into the Saito/Her combination for the well-understood engineering reason of improving probe contact reliability. This was a predictable design choice to enhance manufacturing test accuracy, especially in high-density layouts with narrow signal lines.

  • Additional Grounds: Petitioner asserted additional obviousness challenges, including: (1) combining Saito and Her with Kim (Application # 2002/0139567) to teach signals on the inspection electrode that are not otherwise input or output through the primary connection terminals; (2) combining Taguchi and Her with Saito to teach arranging inspection electrodes between wirings; and (3) combining Taguchi and Her with both Saito and Kim. These grounds relied on similar design modification theories to incorporate specific features taught explicitly by the additional references.

4. Relief Requested

  • Petitioner requests institution of IPR and cancellation of claims 1-12 of the ’512 patent as unpatentable under 35 U.S.C. §103.