PTAB

IPR2025-01482

BOE Technology Group Co Ltd v. Paneltouch Technologies LLC

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Petition
petition

1. Case Identification

2. Patent Overview

  • Title: DISPLAY DEVICE
  • Brief Description: The ’762 patent describes a technique for inspecting display devices for manufacturing defects. The invention uses a dedicated interconnect (a wire) disposed along the peripheral edge of a display or touch-panel substrate to detect cracks or chipping that may occur when individual panels are cut from a larger mother substrate.

3. Grounds for Unpatentability

Ground 1: Obviousness over a Single Reference - Claims 7-10 and 12 are obvious over Miyagawa

  • Prior Art Relied Upon: Miyagawa (Japanese Patent Publication No. JP 2006-171386A).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Miyagawa discloses all limitations of the challenged display panel claims. Miyagawa teaches an LCD display with a “diagnostic wiring” placed on the periphery of a substrate specifically to diagnose defects from cracks. This diagnostic wiring is the claimed “fourth signal interconnect,” as it surrounds the display area and other signal interconnects. It is formed as a conductive thin film disposed along three sides of the substrate, is open at its opposite ends, and is connected to diagnostic pads for inspection, directly mapping to the limitations of independent claim 7.
    • Prior Art Mapping (Dependent Claims): Petitioner asserted that Miyagawa also renders the dependent claims obvious. Miyagawa teaches forming its diagnostic wiring simultaneously with other thin-film components like data lines, which are made of materials like chrome. This directly suggests the interconnect is a "thin metal film layer" (claim 9) that has low transmittance (claim 8). Miyagawa further discloses multi-layer wiring configurations (claim 10) and connecting the diagnostic pads to an IC via a flexible substrate (claim 12).

Ground 2: Obviousness over Combination of Display References - Claims 7-10 and 12 are obvious over Tanabe in view of Miyagawa

  • Prior Art Relied Upon: Tanabe (Application # 2008/0074594) and Miyagawa (Japanese Patent Publication No. JP 2006-171386A).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner contended that Tanabe discloses a conventional LCD panel with all the structural elements of claim 7—including the transparent substrate, video and scanning signal lines, pixel area, and flexible interconnect—but lacks the claimed peripheral crack-detection interconnect. Miyagawa was argued to supply this missing element with its explicit teaching of a peripheral "diagnostic wiring" used for crack detection.
    • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA) would combine these references to improve the manufacturing process of Tanabe’s display. Since manufacturing defects from cutting brittle glass substrates (as used in Tanabe) were a known problem, a POSITA would have been motivated to incorporate Miyagawa's well-described solution for early crack detection to increase yield and reduce waste.
    • Expectation of Success: A POSITA would have had a high expectation of success because the combination involves adding a functionally isolated wire to the periphery of a standard display. Both references describe analogous TFT LCD technology, making the integration straightforward and the outcome—improved defect detection—highly predictable.

Ground 3: Obviousness over Combination of Touch-Panel References - Claims 1-4 and 6 are obvious over Matsuo in view of Nakamura

  • Prior Art Relied Upon: Matsuo (Application # 2009/0244021) and Nakamura (Japanese Patent Publication No. JP 2009-053390A).

  • Core Argument for this Ground:

    • Prior Art Mapping: This ground targets the touch-panel claims. Petitioner argued that Matsuo discloses a touch panel with an "auxiliary line" that functions as a shield wire surrounding the detection area to reduce external noise. This shield wire is structurally identical to the claimed "second signal interconnect." While Matsuo uses this line for noise shielding, Nakamura explicitly teaches that a "conventional shield line" (like Matsuo’s) may be used as a "defective line detection pattern" for manufacturing inspection.
    • Motivation to Combine: A POSITA would be motivated to adapt Matsuo’s existing shield line to also function as a crack-detection line per Nakamura’s teaching. This combination is highly desirable as it achieves two complementary functions—crack detection during manufacturing and noise shielding during operation—with a single component, adding no manufacturing cost or complexity. The fact that both references originated from the same assignee (Epson) further supports the motivation to combine their complementary teachings.
    • Expectation of Success: Success would have been predictable because the modification requires no structural change to Matsuo's device. It merely involves performing a simple continuity check on the existing auxiliary line at the appropriate manufacturing stage, a well-understood technique.

  • Additional Grounds: Petitioner asserted that claims 1-4 and 6 are also obvious over Anno ’704 in view of Miyagawa, arguing that Miyagawa’s crack-detection wiring would have been an obvious addition to the touch-panel device disclosed in Anno ’704 for the same reasons of improving manufacturing efficiency.

4. Relief Requested

  • Petitioner requests institution of an inter partes review and cancellation of claims 1-4, 6-10, and 12 of the ’762 patent as unpatentable.