PTAB

IPR2020-00140

Samsung Display Co Ltd v. Solas OLED Ltd

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Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Active Matrix Electroluminescent Display Apparatus
  • Brief Description: The ’450 patent discloses an active matrix organic electroluminescent display (OLED). Its central inventive concept is a pixel architecture where the electroluminescent (EL) structure—comprising a first electrode, an organic EL layer, and a second electrode—is formed to cover the underlying active elements (transistors). This configuration purports to increase the pixel's light-emitting area (aperture ratio) while simultaneously shielding the light-sensitive transistors from the emitted light.

3. Grounds for Unpatentability

Ground 1: Anticipation of Core Display Structure - Claims 1-2, 4-8, and 15-16 are anticipated by Utsugi under 35 U.S.C. § 102.

  • Prior Art Relied Upon: Utsugi (Patent 5,670,792).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Utsugi, which was not considered during prosecution, discloses every limitation of the primary independent claims (1 and 15) and several dependent claims. Utsugi describes an active matrix OLED display where the "luminescent element EL" is a layered structure that "extends over the capacitor C and the transistors Ql and Qs, covering substantially the entirety of the picture element region." Petitioner contended this structure—comprising an electron injection electrode (first electrode), an organic thin-film layer (EL layer), and a hole injection electrode (second electrode)—directly corresponds to the claimed structure covering the active elements. Furthermore, Petitioner asserted that Utsugi’s first electrode is made of a "metallic material MgAg," which would inherently be reflective and shield visible light, thus meeting the final key limitation of the independent claims.

Ground 2: Obviousness of Roughened Electrode - Claim 3 is obvious over Utsugi in view of Manabe.

  • Prior Art Relied Upon: Utsugi (Patent 5,670,792) and Manabe (Japanese Patent Application Publication JPH053079).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that while Utsugi discloses the base display apparatus of claim 1, it does not explicitly teach the limitation of claim 3, which requires the first electrode to have a "rough surface" in contact with the EL layer. Manabe, also not cited during prosecution, was presented as solving the known problem of viewing-angle-dependent luminance variations in OLED displays caused by light wave interference. Manabe’s solution is to roughen the surface of the metal electrode in contact with the organic EL layer, which averages out light path differences and improves display quality.
    • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA) would have been motivated to improve the viewing angle performance of the display taught in Utsugi, a common goal in display design. Since Utsugi’s display uses a reflective electrode and would suffer from the same interference-based viewing angle issues addressed by Manabe, a POSITA would combine Manabe’s well-known solution with Utsugi’s display structure.
    • Expectation of Success: A POSITA would have a high expectation of success, as the combination involves applying a known technique (roughening an electrode) to a known device (Utsugi’s display) to achieve a predictable improvement in performance. The materials disclosed in both references (magnesium-based alloys) are similar, making the integration straightforward.

Ground 3: Obviousness of Color Display Features - Claims 9, 11-13, and 17-18 are obvious over Utsugi in view of Eida.

  • Prior Art Relied Upon: Utsugi (Patent 5,670,792) and Eida (WO 96/25020).

  • Core Argument for this Ground:

    • Prior Art Mapping: Petitioner asserted that Utsugi provides the foundational active matrix OLED structure, while Eida teaches the specific color-generation features required by this group of dependent claims. Eida, which is substantively identical to a reference considered by the Examiner, explicitly teaches the use of "wavelength conversion layer(s)" and "filter(s)" to create a full-color display. Specifically, Eida discloses using "fluorescent layers" to convert blue light into red and green light and arranging color filters over these layers to "promote the color purity," directly mapping to the claim limitations.
    • Motivation to Combine: Utsugi states that organic EL structures were "attracting attention" for realizing "full-colored" displays but provides no details on achieving color. A POSITA seeking to create a full-color display based on Utsugi's efficient pixel architecture would naturally look to other references, like Eida, that specifically address color generation in similar top-emitting OLED devices. Eida provides an express teaching for optimizing a multi-color display.
    • Expectation of Success: The combination represented a predictable integration of known technologies. A POSITA would have reasonably expected that adding Eida's color conversion and filtering layers on top of Utsugi's EL structure would successfully produce a full-color display with improved efficiency and color purity.

  • Additional Grounds: Petitioner asserted that claims 1-2, 4-8, and 15-16 are also obvious over Utsugi alone (Ground II), arguing that to the extent any minor element was not explicitly disclosed in Utsugi, it represented an obvious design choice to a POSITA.

4. Relief Requested

  • Petitioner requested the institution of an inter partes review and cancellation of claims 1-9, 11-13, and 15-18 of the ’450 patent as unpatentable.