PTAB

IPR2025-01579

Tianma Microelectronics Co Ltd v. LG Display Co Ltd

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Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Organic Light Emitting Display and Method of Fabricating the Same
  • Brief Description: The ’394 patent discloses an Organic Light Emitting Diode (OLED) display with an integrated touch screen. The technology aims to reduce device thickness and weight by disposing touch sensor components, including electrodes and conductive lines, directly on the display's top encapsulation layer, thereby eliminating a separate touch panel.

3. Grounds for Unpatentability

Ground 1: Claims 1-4 and 6-8 are obvious over Kwon224 in view of Kim524.

  • Prior Art Relied Upon: Kwon224 (Application # 2016/0378224) and Kim524 (Application # 2016/0170524).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Kwon224 discloses the foundational elements of the ’394 patent, including an OLED display with integrated touch sensors (first/second touch electrodes and connecting bridges) formed directly on a thin-film encapsulation (TFE) layer. Petitioner contended that Kwon224 also teaches a pixel definition layer (PXL) that functions as the claimed "bank," which overlaps the connecting bridges—a key feature added to the independent claims during prosecution to secure allowance. Kim524 was introduced to supply the teaching of a stacked conductive line structure connected through contact holes, a detail Petitioner asserted was absent in Kwon224.
    • Motivation to Combine: Petitioner argued a person of ordinary skill in the art (POSITA) would combine Kim524's teachings with Kwon224's device. Kwon224 allegedly provides limited detail on the vertical structure for its conductive lines, whereas Kim524, addressing analogous problems in OLED touchscreens, explicitly discloses a stacked signal line configuration to improve electrical performance. A POSITA would integrate Kim524's well-understood stacked structure into Kwon224’s design to achieve the known benefits of reduced resistance and improved touch sensitivity.
    • Expectation of Success: Petitioner asserted a high expectation of success, as combining the references involves implementing a stacked line configuration with contact holes—a standard and well-established fabrication technique in the display industry. The device architectures and materials disclosed in both references were argued to be fully compatible.

Ground 2: Claims 9-16 and 18 are obvious over Kwon224 and Kim524 in view of Zhu837.

  • Prior Art Relied Upon: Kwon224 (Application # 2016/0378224), Kim524 (Application # 2016/0170524), and Zhu837 (Application # 2016/0313837).

  • Core Argument for this Ground:

    • Prior Art Mapping: This ground builds upon the base combination of Kwon224 and Kim524, adding Zhu837 to teach the limitations of claim 9, which requires the encapsulation unit to comprise at least one inorganic layer and at least one organic layer. Petitioner asserted that Zhu837 discloses a multi-layered encapsulation structure composed of alternating inorganic and organic films. The argument was that a POSITA would be motivated to replace the single-material insulating layer taught in Kwon224 with the more robust multi-layer encapsulation structure of Zhu837.
    • Motivation to Combine: The primary motivation was to enhance device protection, reliability, and design flexibility. Petitioner argued that Zhu837’s multi-layer encapsulation offers superior protection against environmental factors like moisture compared to a single-layer structure. This modification was framed as an ordinary design choice to improve the overall durability and performance of the combined Kwon224/Kim524 device.
    • Expectation of Success: Petitioner contended there was a reasonable expectation of success, describing the modification as a predictable "like-for-like layer swap." The insulating structures in both Kwon224 and Zhu837 serve the same fundamental purpose of electrical isolation and are situated in the same location within the device stack, making the substitution a routine and well-understood practice in flexible OLED fabrication.

  • Additional Grounds: Petitioner asserted further obviousness challenges for claim 5 (adding Jang513 to the Kwon224/Kim524 combination to teach connecting conductive lines to touch pads on the substrate), claim 17 (adding Kim481 to the Kwon224/Kim524 combination to teach routing conductive lines along a side surface of the encapsulation unit), and claim 19 (combining Kim481 and Kim524).

4. Relief Requested

  • Petitioner requests institution of an inter partes review and cancellation of claims 1-19 of the ’394 patent as unpatentable.