PTAB

IPR2021-01058

Tianma Microelectronics Co Ltd v. Japan Display Inc

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Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Liquid Crystal Display Device
  • Brief Description: The ’142 patent relates to a liquid crystal display (LCD) device designed to prevent "disclination," an undesirable phenomenon where liquid crystal molecules rotate incorrectly near the edges of electrode openings. The patent purports to solve this by overlapping an end portion of a slit in the upper pixel electrode with a window-shaped opening in the lower common electrode.

3. Grounds for Unpatentability

Ground 1: Obviousness over Lee in view of No - Claims 1-3, 5, 6, and 8 are obvious over Lee in view of No.

  • Prior Art Relied Upon: Lee (Patent 7,599,015) and No (Korean Laid-Open Patent No. 2002-0085245).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Lee discloses a fringe-field switching (FFS) LCD structure containing all elements of independent claim 1 except for the explicit overlap between the end of a pixel electrode slit and the opening in the common electrode. Lee teaches an LCD with an upper pixel electrode and a lower common electrode separated by an insulation layer. The pixel electrode has slits (electric field opening parts) to drive the liquid crystals, and the common electrode has a window-shaped opening to facilitate electrical connection to underlying drain wiring. Lee’s figures show the ends of the pixel electrode slits positioned adjacent to, but not overlapping, this opening. Petitioner asserted that No, another reference addressing FFS LCDs, explicitly teaches the missing element. No discloses that overlapping the ends of pixel electrode slits with holes in the counter (common) electrode is a known technique to "suppress[] the occurrence of disclination lines" caused by electric field distortion at the slit edges.
    • Motivation to Combine: Petitioner contended that a person of ordinary skill in the art (POSITA) would have been motivated to combine the teachings of Lee and No. Both references are from the same field of endeavor (thin-film transistor LCDs) and address the same known problem of disclination. A POSITA, recognizing that the slit ends in Lee's device would be prone to disclination, would have looked to known solutions in the art. No provides a direct, explicit solution by teaching the benefits of overlapping the slit ends with the common electrode opening. Therefore, a POSITA would combine No's disclination-suppression technique with Lee's LCD structure to improve screen quality.
    • Expectation of Success: Petitioner argued a POSITA would have had a high expectation of success. The proposed modification was a simple change to the pixel mask layout to extend the slits, requiring only routine skill. Because No expressly teaches that this configuration prevents disclination, applying this known solution to the analogous structure in Lee would have predictably resulted in the same benefit of improved display performance.
    • Dependent Claims: Petitioner further argued that the limitations of dependent claims 2, 3, 5, 6, and 8 were also disclosed or rendered obvious by the combination. Lee's structure was alleged to meet the geometric arrangement of the opening relative to the electrode (claim 2), while the purpose of suppressing disclination (claim 3) was the express motivation from No. Lee was also asserted to teach the switching element (claim 5) and the slit shape (claim 8). Finally, Petitioner argued that No teaches against overlapping the contact hole (claim 6), making it obvious to design the overlap to avoid it and its associated performance degradation.

4. Key Claim Construction Positions

  • "disclination": Petitioner noted that in related district court litigation, the parties agreed to construe this term as "a phenomenon in which the direction of rotation of liquid crystal molecules changes depending on their location." This construction aligns with the problem the ’142 patent and the prior art purport to solve.

5. Arguments Regarding Discretionary Denial

  • §314(a) (Fintiv): Petitioner argued extensively that the Board should not exercise its discretion to deny institution based on the parallel district court litigation. Key arguments included:
    • The scheduled trial date in the district court was speculative due to a pending motion to transfer venue.
    • Petitioner acted with diligence, filing the IPR petition five months after the Patent Owner served its infringement contentions.
    • Petitioner stipulated that if IPR is instituted, it will not pursue in the district court any invalidity ground that was raised or reasonably could have been raised in the petition, eliminating concerns of duplicative efforts and conflicting decisions.
    • The petition challenges claim 2, which is not asserted in the parallel litigation, meaning the IPR resolves issues beyond the scope of the court case.
    • The petition presents a strong case on the merits, which weighs heavily in favor of institution.
  • §325(d): Petitioner asserted that denial under §325(d) would be improper because the primary references, Lee and No, were not cited or considered during the original prosecution of the ’142 patent. The petition argued that this new combination of prior art teaches the very feature that the Examiner previously found to be missing from the art of record, making the challenge non-cumulative.

6. Relief Requested

  • Petitioner requests that the Board institute inter partes review and cancel claims 1-3, 5, 6, and 8 of the ’142 patent as unpatentable.