PTAB

IPR2023-00987

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

Log In

1. Case Identification

2. Patent Overview

  • Title: Pixel Arrangement Structure for Organic Light Emitting Display Device
  • Brief Description: The ’803 patent describes a pixel arrangement for an organic light emitting diode (OLED) display. The structure arranges red, green, and blue pixels in a "virtual square," where a green pixel is at the center and red and blue pixels are at the vertices, with the red and blue pixels having a larger area than the green pixel to improve display lifespan.

3. Grounds for Unpatentability

Ground 1: Obviousness over Matthies and Yamada - Claims 1-5 and 19-21 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 an OLED display with red, green, and blue sub-pixels arranged in a repeating square "quad sub-pixel structure." This arrangement inherently created the claimed "virtual square" with a green pixel (the "first pixel") at the center and red and blue pixels (the "third" and "second" pixels) at the vertices. However, Matthies’ examples showed equally sized pixels. Petitioner asserted that Yamada taught the precise relative sizing required by the claims to solve OLED deterioration. Specifically, Yamada taught that for OLEDs, the blue pixel (lowest emission efficiency) should be made largest and the green pixel (highest emission efficiency) smallest to prolong display life.
    • Motivation to Combine: A POSITA would combine Yamada's teachings with Matthies' pixel layout to solve the known problem of OLED pixel aging and decay, which Matthies explicitly acknowledged. Yamada provided a well-established solution (resizing pixels based on emission efficiency) to this known problem. Applying this solution would predictably improve the lifespan of Matthies’ display and simplify its driving circuitry, which was complex due to the need to supply different currents to same-sized pixels.
    • Expectation of Success: A POSITA would have had a high expectation of success because resizing OLED pixels was a routine design choice to improve display lifetime. Both references related to OLED pixel design, and Matthies itself contemplated that pixel geometry could be adjusted.

Ground 2: Obviousness over Phan - Claims 1-4 and 19-21 are obvious over Phan.

  • Prior Art Relied Upon: Phan (Patent 7,091,986).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner contended that Phan, as a standalone reference, rendered most challenged claims obvious. Phan taught an OLED display with red, green, and blue dots arranged in a repeating "square quad pixel" grid. This configuration inherently formed the claimed "virtual square" with a green dot at its center. Critically, Phan’s Figure 11b disclosed a pixel structure where the central crosspoint was shifted, resulting in dots with non-equal areas. In this embodiment, the blue dot ("second pixel") had a larger area than the red dot ("third pixel"), directly teaching a key limitation of the ’803 patent without requiring combination with other art.
    • Motivation to Combine (N/A): This ground was asserted based on the direct teachings of a single reference.

Ground 3: Obviousness over Murai and Yamada - Claims 1-5 and 19-21 are obvious over Murai in view of Yamada.

  • Prior Art Relied Upon: Murai (JP 4496852 B2) and Yamada (Patent 6,366,025).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Murai taught an OLED display with red, green, and blue pixels arranged in a square grid that formed the claimed "virtual square." Murai also disclosed adjusting pixel sizes by using corner "cut-offs," and its Figure 3 showed an embodiment where green pixels had two cut-offs, making them smaller than the red and blue pixels, which had no cut-offs. To meet the remaining limitation that the blue pixel is larger than the red pixel, Petitioner argued for applying Yamada’s teachings on relative pixel sizing based on emission efficiency.
    • Motivation to Combine: The motivation to combine Murai with Yamada was similar to that for combining Matthies with Yamada. A POSITA would have sought to improve the display life of Murai's device by addressing OLED deterioration. Yamada provided the known solution of resizing pixels according to their emission efficiencies (blue largest, green smallest). Because Murai already taught the concept of variably sized pixels via cut-offs, applying Yamada's specific sizing scheme would have been a predictable and routine design modification.
    • Expectation of Success: A POSITA would have reasonably expected success, as Murai was already open to resizing pixels, and applying Yamada's well-known technique for improving OLED lifetime was a straightforward modification.
  • Additional Grounds: Petitioner asserted an additional obviousness challenge for claim 5 over Phan in view of Yamada, arguing that Yamada provided the motivation to resize Phan's red pixel to be larger than its green pixel to further improve display life.

4. Arguments Regarding Discretionary Denial

  • Petitioner argued that discretionary denial under §325(d) would be inappropriate because the primary prior art references relied upon—Matthies, Phan, and Murai—were never considered by the examiner during prosecution. Petitioner asserted that while Yamada was cited on the face of the ’803 patent, it was not substantively discussed or used in any rejection. Therefore, the arguments presented in the petition were substantially different from those considered by the Patent Office. Petitioner also argued against denial under §314(a), stating that a pending related ITC matter should have no bearing on the Board's decision to institute, per PTAB interim procedures.

5. Relief Requested

  • Petitioner requests institution of an inter partes review and cancellation of claims 1-5 and 19-21 of the ’803 patent as unpatentable.