PTAB

IPR2025-01477

BOE Technology Group Co Ltd v. Samsung Display Co Ltd

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petition

1. Case Identification

2. Patent Overview

  • Title: Display Device
  • Brief Description: The ’496 patent describes an Organic Light Emitting Diode (OLED) display device with an integrated touch-sensing unit. The invention focuses on the specific layered arrangement, including a multi-layer thin-film encapsulation (TFE) layer over the OLEDs and a touch unit formed on top of the TFE layer, wherein the touch unit comprises two conductive patterns with different thicknesses arranged in a bridge structure.

3. Grounds for Unpatentability

Ground 1: Obviousness over Her, Cok, and Cho - Claims 1-10 and 12 are obvious over Her in combination with Cok and Cho.

  • Prior Art Relied Upon: Her (Application # 2015/0049030), Cok (Patent 6,867,549), and Cho (Application # 2014/0117330). The ground also optionally includes Hsieh (Chinese App. # CN105320372A) and Kobayashi (Japanese Patent # JPH0646348B2) for teachings on conductive layer thickness.
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Her disclosed the foundational structure of an OLED display with a touch panel formed directly on its sealing (encapsulation) layer. Her’s touch panel includes two sets of electrodes with sensor parts and connection parts, which can be arranged with bridges on a separate conductive layer to avoid intersections (an underpass-type bridge). However, Her did not explicitly teach a multi-layer TFE or varying pixel sizes. To supply these elements, Petitioner asserted that Cho taught a well-known multi-layered TFE comprising alternating inorganic and organic layers to protect the OLEDs from moisture and oxygen. Cok was cited for its teaching that differently colored (red, green, blue) light-emitting areas in an OLED display should be sized differently to account for variations in luminous efficiency, degradation rates, and human eye sensitivity.
    • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA) would have been motivated to modify Her’s display by incorporating the teachings of Cok and Cho to create a more robust and visually optimized device. A POSITA would implement Cho’s well-known alternating organic/inorganic TFE structure into Her’s device to improve durability and reliability, a standard goal in OLED manufacturing. Similarly, a POSITA would apply Cok's established principles of differential pixel sizing to Her’s display to improve image quality and device lifetime, which were known industry objectives. For the relative thickness of the conductive layers, Petitioner argued a POSITA would be motivated to make the upper touch sensor layer thicker than the lower bridge layer, as taught by Hsieh and Kobayashi, to mitigate known manufacturing problems like step coverage and cracking at intersections, thereby improving conductivity and durability.
    • Expectation of Success: Petitioner contended that a POSITA would have had a reasonable expectation of success because the combination involved applying conventional, well-understood solutions (multi-layer TFE, differential pixel sizing, layer thickness optimization) to their known problems within a standard OLED display architecture.

Ground 2: Obviousness over Lee-979, Kim, and Cok - Claims 1-10 and 12 are obvious over Lee-979 in combination with Kim and Cok.

  • Prior Art Relied Upon: Lee-979 (Application # 2014/0145979), Kim (Application # 2013/0341651), and Cok (Patent 6,867,549).

  • Core Argument for this Ground:

    • Prior Art Mapping: Petitioner presented Lee-979 as an alternative primary reference that disclosed an OLED display with a touch-sensing unit integrated within a multi-layered encapsulation layer. Lee-979 taught using a transparent conductive material, such as Indium Tin Oxide (ITO), for its touch sensors. Petitioner argued that it would have been obvious to replace Lee-979’s ITO sensors with the metal-mesh sensors taught by Kim. Kim disclosed touch sensors made of metal mesh, with the mesh lines positioned in the non-emissive gaps between pixels to avoid obstructing light, thereby improving flexibility and conductivity compared to ITO. Cok was again relied upon for the teaching of varying the sizes of the red, green, and blue light-emitting areas.
    • Motivation to Combine: A POSITA would have been motivated to substitute the ITO-based sensors in Lee-979 with the metal-mesh sensors from Kim to overcome the known drawbacks of ITO, particularly its brittleness and higher resistance, which made it less suitable for flexible displays. This modification represented a simple substitution of one known touch-sensor material for another to achieve the predictable benefits of improved durability and electrical performance. The motivation to incorporate Cok's teachings on pixel sizing was the same as in Ground 1: to optimize the display's visual performance and longevity based on well-established principles.
    • Expectation of Success: Petitioner asserted a high expectation of success, as this combination merely involved applying a known, superior material and structure (Kim's metal mesh) for a component (touch sensor) within a conventional display device (Lee-979) to achieve its well-documented advantages.

  • Additional Grounds: Petitioner asserted further obviousness challenges for claims 11 and 17 by adding Lee-P12 (a 2004 SID Digest article) for its seven-transistor pixel driving circuit designed to compensate for threshold voltage degradation. Additional grounds for claims 13-16 were asserted by adding Ka (Application # 2014/0002385) for its specific teachings on making flexible displays foldable.

4. Relief Requested

  • Petitioner requests institution of an inter partes review and cancellation of claims 1-17 of the ’496 patent as unpatentable.