PTAB

IPR2025-01545

BOE Technology Group Co Ltd v. Samsung Display Co Ltd

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Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Pixel Arrangement Structures for OLED Displays
  • Brief Description: The ’066 patent discloses pixel arrangement structures for organic light-emitting diode (OLED) displays. The technology centers on an RGBG (red, green, blue, green) pixel structure, where green pixels are twice as numerous as red or blue pixels, arranged in a specific geometric relationship to a "virtual square" to purportedly improve deposition reliability and aperture ratio.

3. Grounds for Unpatentability

Ground 1: Obviousness over Cok and Suh - Claims 1-2, 4-5, 10, 12-15, 17-23, and 28-30 are obvious over Cok in view of Suh.

  • Prior Art Relied Upon: Cok (Patent 6,867,549) and Suh (Application # 2009/0033598).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Cok discloses the foundational RGBG pixel arrangement for OLED displays and provides a formula to optimize the relative sizes of the different colored pixels to improve display lifetime and color quality. Suh teaches a common manufacturing feature for OLED displays: a pixel defining layer (PDL) that creates physical boundaries between pixels. Petitioner asserted that the combination of Cok's pixel layout and Suh's PDL teaches the core limitations of the independent claims, including the plurality of red, green, and blue pixels separated by a PDL.
    • Motivation to Combine: A person of ordinary skill in the art (POSITA) would combine Suh's PDL with Cok's pixel arrangement to improve manufacturability. Cok's formula results in pixels of varying sizes to optimize performance; Suh's PDL provides the clear pixel definition and separation necessary to accurately and reliably manufacture these variably sized pixels. This represents a simple application of a known structural element (the PDL) to improve a known pixel layout.
    • Expectation of Success: A POSITA would have a high expectation of success, as the combination involves integrating well-understood structures and layouts within the same field of OLED display technology to achieve predictable benefits in manufacturing precision.

Ground 2: Obviousness over Credelle-379, Cok, and Suh - Claims 1-2, 4-5, 10-13, 15, and 17-29 are obvious over Credelle-379 in view of Cok and Suh.

  • Prior Art Relied Upon: Credelle-379 (Patent 7,492,379), Cok (Patent 6,867,549), and Suh (Application # 2009/0033598).

  • Core Argument for this Ground:

    • Prior Art Mapping: This ground presents an alternative combination where Credelle-379 serves as the primary reference. Credelle-379 discloses an alternative RGBG pixel arrangement for OLED displays and explicitly teaches that the sizes, aspect ratios, and positions of the pixels can be altered.
    • Motivation to Combine: A POSITA would be motivated to apply Cok's optimization formula to the pixel arrangement taught in Credelle-379. Because Credelle-379 expressly contemplates adjusting pixel sizes, using Cok's well-known formula to perform this adjustment for the purpose of improving display lifetime would be an obvious design choice. A POSITA would then incorporate Suh's PDL for the same reasons as in Ground 1: to ensure the precise, optimized pixel dimensions could be manufactured accurately.
    • Expectation of Success: The combination would have been straightforward and expected to succeed, as it involves applying a known optimization formula to a flexible base design (Credelle-379) that explicitly allows for such modification.

  • Additional Grounds: Petitioner asserted further obviousness challenges against specific dependent claims.

    • Claims 3, 16, and 21 were challenged over the Credelle-379/Cok/Suh combination in view of Elliott-724 (Application # 2004/0051724). Elliott-724, a parent to Credelle-379, teaches using manufacturable hexagonal pixel shapes, which a POSITA would have found obvious to substitute into the base combination.
    • Claim 11 was challenged over both the Cok/Suh combination (as Ground 2 in the petition) and the Credelle-379/Cok/Suh combination (as Ground 5 in the petition) by additionally applying Hong (Application # 2011/0234550). Hong teaches maintaining equal spacing between adjacent pixel pairs to prevent shadowing defects caused by deposition mask deformation, a known manufacturing issue a POSITA would have been motivated to solve.

4. Arguments Regarding Discretionary Denial

  • Petitioner argued that discretionary denial would be inappropriate. The core prior art references, including Cok, Hong, and the application leading to Credelle-379, were submitted to the Examiner during prosecution in a voluminous Information Disclosure Statement but were never substantively applied in a rejection. Other key references (Suh and Elliott-724) were not considered by the Examiner at all. Petitioner also noted that the Board has previously found similar claims in parent patents of the ’066 patent unpatentable in separate IPR proceedings. Finally, the parallel district court litigation is in its early stages with no trial date set, meaning a Final Written Decision in this IPR would issue well before a potential trial.

5. Relief Requested

  • Petitioner requests institution of an inter partes review and cancellation of claims 1-5, 10-23, and 28-30 of Patent 11,626,066 as unpatentable.