PTAB

IPR2023-01075

Mianyang BOE Optoelectronics Technology Co Ltd v. Samsung Display Co Ltd

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petition

1. Case Identification

2. Patent Overview

  • Title: Pixel Arrangement Structure for Organic Light Emitting Display Device
  • Brief Description: The ’578 patent describes a specific geometric arrangement of red, green, and blue pixels for an Organic Light Emitting Diode (OLED) display. The arrangement claims to improve display lifespan by making the green pixels smaller than the red and blue pixels and arranging them in sets such that the region occupied by the green pixels is "entirely offset" from the others.

3. Grounds for Unpatentability

Ground 1: Obviousness over Matthies and Yamada - Claims 1-6, 10, 12, 17-19, 21-23, 41-42, 44-47, and 52 are obvious over Matthies in view of Yamada.

  • Prior Art Relied Upon: Matthies (Patent 6,897,855) and Yamada (Patent 6,366,025).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Matthies taught the core geometric pixel structure required by the independent claims. Matthies disclosed an OLED display with red, green, and blue sub-pixels arranged in a repeating square matrix, forming the claimed "sets" of pixels extending along parallel "lines" in multiple "directions." However, Matthies taught equally sized sub-pixels. Petitioner asserted that Yamada supplied the missing limitations by teaching the resizing of OLED pixels based on their emission efficiencies to prolong display life—a known problem in the art. Specifically, Yamada taught making the green pixels (highest efficiency) smallest and the blue pixels (lowest efficiency) largest. Applying this teaching to Matthies’s layout would result in smaller green pixels, which in turn would create a pixel region that is "entirely offset" from the larger red and blue pixels. This modification also inherently results in the claimed distance relationships, such as the shortest distance between green pixels being greater than the shortest distance between adjacent red and blue pixels.
    • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA) would combine Yamada’s teachings with Matthies’s display to solve the well-known problem of OLED pixel degradation, which Matthies acknowledged but addressed with more complex electrical compensation circuitry. Yamada taught that resizing pixels according to emission efficiency extends display life and simplifies the required driving circuitry, providing a clear motivation to modify Matthies’s design. This modification was presented as a known design trade-off to improve performance and reduce manufacturing costs, consistent with Matthies's own stated goals.
    • Expectation of Success: Petitioner asserted a high expectation of success, as resizing pixels to improve display lifetime was a routine and predictable technique in OLED design at the time. Both references concerned OLED pixel layouts, and the proposed combination involved applying a known solution to a known problem with predictable results.

Ground 2: Obviousness over Matthies, Yamada, and Hong - Claims 40, 43, 45-47, and 51-52 are obvious over Matthies and Yamada in view of Hong.

  • Prior Art Relied Upon: Matthies (Patent 6,897,855), Yamada (Patent 6,366,025), and Hong (Application # 2011/0234550).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground built upon the combination of Matthies and Yamada from Ground 1 to address dependent claims requiring a specific pixel shape. These claims required pixels with features like two "elongated sides" and "connection portions," consistent with an octagonal shape. Petitioner argued that while the base combination of Matthies and Yamada taught the overall pixel arrangement and relative sizing, Hong taught the specific pixel shape. Hong disclosed using pixels with a rectangular shape and "truncated" corners (i.e., an octagonal shape) in an OLED display to improve aperture ratio and resolution.
    • Motivation to Combine: A POSITA would have been motivated to incorporate Hong’s pixel shape into the display taught by the Matthies/Yamada combination as a simple design choice to further optimize display performance. The ’578 patent itself described pixel shape as "arbitrarily given" and "stereotypically polygonal," suggesting it was not a critical inventive aspect. Hong explicitly stated that its octagonal shape provided known benefits, making it an obvious and desirable modification for a skilled artisan seeking to improve a conventional display design.
    • Expectation of Success: The expectation of success was high, as modifying pixel shape was a common and predictable design variable in OLED displays. A POSITA would have reasonably expected that substituting one known polygonal pixel shape for another would predictably yield the benefits described by Hong without disrupting the overall pixel arrangement taught by Matthies and Yamada.

4. Arguments Regarding Discretionary Denial

  • Petitioner argued that discretionary denial under 35 U.S.C. §325(d) would be inappropriate because the primary reference, Matthies, was not cited or considered during prosecution. Petitioner contended that Matthies was substantively different from the art considered by the Examiner because it taught key geometric limitations (e.g., "virtual quadrangles," specific line arrangements) that the Examiner had previously found missing from the prior art of record.
  • Petitioner also argued against denial under §314(a), asserting that a parallel International Trade Commission (ITC) investigation had no bearing on the Board’s decision to institute, per the Board's then-current interim procedure for discretionary denials.

5. Relief Requested

  • Petitioner requested institution of an inter partes review and cancellation of claims 1-6, 10, 12, 17-19, 21-23, 40-47, and 51-52 of the ’578 patent as unpatentable.