PTAB

IPR2025-01544

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 Structure
  • Brief Description: The ’616 patent discloses a pixel arrangement structure for Organic Light Emitting Diode (OLED) displays. The structure specifies a geometric relationship between first (green), second (blue), and third (red) pixels, where a first pixel's center coincides with the center of a "virtual square" whose vertices are defined by the centers of adjacent second and third pixels.

3. Grounds for Unpatentability

Ground 1: Claims 1-5, 10, 11, and 13 are obvious over Cok in view of Hong.

  • Prior Art Relied Upon: Cok (Patent 6,867,549) and Hong (Application # 2011/0234550).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Cok taught an OLED display with a repeating RGBG pixel pattern. A Person of Ordinary Skill in the Art (POSITA) would have understood to arrange these repeating patterns in a uniform, equal-spaced grid for accurate image display. This arrangement inherently creates the claimed geometric structure where a green pixel (first pixel) is centered within a virtual square formed by the centers of surrounding red and blue pixels (third and second pixels). Cok further disclosed that pixel sizes could be adjusted based on material properties, such that the blue pixel could be larger than the red pixel and both could be larger than the green pixel.
    • Motivation to Combine: A POSITA would combine Cok's pixel arrangement with Hong's teachings for two primary reasons. First, Hong taught spacing pixels a uniform distance apart to prevent "shadowing effects" during the manufacturing deposition process. This would motivate applying consistent spacing to Cok’s layout to improve manufacturability. Second, Hong taught adjusting pixel sizes based on the emission efficiency of different colored OLED materials to achieve uniform brightness and improve white balance. A POSITA would apply this principle to Cok's design, using newer, more efficient materials developed since Cok, to improve display lifetime and performance.
    • Expectation of Success: Both Cok and Hong related to OLED display pixel arrangements and addressed known problems in the field. Combining Hong’s teachings on specific spacing and sizing with Cok's foundational RGBG layout was a straightforward application of known design principles to achieve predictable improvements.

Ground 2: Claims 1-5, 10, 11, and 13 are obvious over Credelle-379 in view of Hong.

  • Prior Art Relied Upon: Credelle-379 (Patent 7,492,379) and Hong (Application # 2011/0234550).

  • Core Argument for this Ground:

    • Prior Art Mapping: Petitioner asserted that Credelle-379 disclosed an RGBG pixel arrangement for OLEDs and explicitly taught that the size, aspect ratio, spacing, and relative positions of the sub-pixels could be altered. Petitioner argued that modifying the arrangement of Credelle-379, such as by vertically offsetting the green pixels as shown in Credelle-379's own figures, would result in the claimed geometry of a central green pixel surrounded by red and blue pixels.
    • Motivation to Combine: A POSITA would be motivated to modify the pixel sizes in Credelle-379 based on Hong's teachings. Given the rapid development in OLED materials between the filing of Credelle-379 (2002) and Hong (2010), a POSITA would use newer materials where green was most efficient and blue was least efficient. To balance brightness, a POSITA would follow Hong's guidance to make the green pixels smallest and blue pixels largest, improving display lifetime and power consumption. Furthermore, a POSITA would look to Hong to supply manufacturing details absent from Credelle-379, adopting Hong’s uniform spacing to reduce shadowing during deposition.
    • Expectation of Success: The combination was argued to be predictable. Credelle-379 itself contemplated that its pixel layout was adjustable. Applying Hong's more modern sizing and spacing principles was a simple substitution of one set of dimensions for another to optimize a known display layout, using the same underlying OLED technology.

  • Additional Grounds: Petitioner asserted an additional obviousness challenge for claims 6-9 and 12 based on the combination of Credelle-379, Hong, and Elliott-724 (Application # 2004/0051724). This ground relied on the same core arguments as Ground 2, with Elliott-724 (a parent application to Credelle-379) being added to teach that sub-pixels could have hexagonal shapes, as required by the dependent claims.

4. Arguments Regarding Discretionary Denial

  • Petitioner argued against discretionary denial under §325(d) because the prior art and arguments were not previously considered or were considered in a materially different way. Specifically, Hong and Elliott-724 were never considered by the Examiner, and Petitioner’s reliance on Cok’s RGBG layout was materially different from the Examiner’s previous citation.
  • Petitioner also argued against discretionary denial under Fintiv, stating that the parallel district court litigation was in its earliest stages with no trial date set, while the IPR would result in a Final Written Decision much sooner. Furthermore, the Board had previously instituted IPRs and found claims unpatentable in three related patents from the same family, which Petitioner argued counseled against denial.

5. Relief Requested

  • Petitioner requested the institution of an inter partes review and the cancellation of claims 1-13 of the ’616 patent as unpatentable.