PTAB

IPR2015-00757

Sony Corp v. Delaware Display Group LLC

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Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Light Redirecting Films and Film Systems
  • Brief Description: The ’196 patent relates to light redirecting films and systems used in backlights for displays like LCDs. The technology purports to improve image brightness and quality by using a backlight with specific "deformities" that cause light to be emitted at relatively low angles, which is then redirected by an overlying film toward the viewer.

3. Grounds for Unpatentability

Ground 1: Anticipation of Claims 1-3, 5, 10, 18, and 19 by Kojima

  • Prior Art Relied Upon: Kojima (Patent 5,797,668).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Kojima, which discloses a surface illuminant device for an LCD, teaches every element of the challenged claims. Kojima’s light guide plate (3) corresponds to the claimed backlight, its linear light source (4) meets the light source limitation, and its lens film (1) with triangular prisms (2) is the claimed light redirecting film with optical elements. Crucially, Petitioner asserted that the "minute white dots" (7) printed on Kojima’s light guide plate to scatter light are the claimed "deformities." Kojima expressly states that these deformities cause "most light rays" to exit the guide plate at a "peak exit angle," which Petitioner contended meets the limitation of emitting light at "relatively low angles."
    • Key Aspects: The argument hinged on mapping Kojima’s specific structural elements—particularly the printed white dots—directly onto the functional language of the ’196 patent’s claims.

Ground 2: Anticipation of Claims 22-25 by Kalantar

  • Prior Art Relied Upon: Kalantar (Japanese Publication No. JP H09-292531).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner contended that Kalantar anticipates the claims directed to a backlight system with a high light-extraction efficiency. Kalantar discloses a light guiding plate (12) with an input edge (13) and an output surface (15), corresponding to the claimed backlight. The "protrusions" (23) on Kalantar’s backlight, which are described as having well-defined shapes, were mapped to the claimed "individual optical deformities." For the key limitation in claim 22 requiring deformities that cause "60 to 70% or more of the light" to be emitted, Petitioner argued that Kalantar's stated goal of "efficiently totally reflecting" incident light inherently meets this threshold. Kalantar’s separate light deflecting plate (16) with prism surfaces (27) was identified as the claimed "light redirecting film."

Ground 3: Obviousness of Claims 1-21 over Ando in view of Jannson

  • Prior Art Relied Upon: Ando (Patent 5,808,784) and Jannson (Patent 5,838,403).

  • Core Argument for this Ground:

    • Prior Art Mapping: Petitioner asserted that Ando discloses a backlight system for an LCD, including an optical conductor (light guide 51) and an overlying lens array sheet (1), which meets most limitations of claim 1. However, Petitioner acknowledged that Ando does not explicitly teach deformities that cause light emission at relatively low angles for increased brightness. To supply this element, Petitioner turned to Jannson, which discloses a collimating waveguide (150) with "substantially parallel optical elements" (160) specifically designed to cause light to leak at a "near zero degree angle" to the top surface, thereby increasing brightness.
    • Motivation to Combine: Petitioner argued a person of ordinary skill in the art (POSITA) would combine Ando and Jannson because both references address the same problem of creating brighter, more efficient LCD backlights. A POSITA would have been motivated to incorporate Jannson’s high-efficiency, low-angle deformities into Ando’s basic backlight structure as a simple substitution of known elements to achieve the predictable result of improved brightness.
    • Expectation of Success: The combination was presented as a straightforward application of known light-guiding principles from Jannson to the established backlight structure in Ando, with a high expectation of achieving the desired increase in brightness and efficiency.

  • Additional Grounds: Petitioner asserted additional obviousness challenges, including that claims 1-3, 5, 7-13, 18, 19, and 21 are obvious over Koike (Patent 5,982,540) in view of Kaneko (Patent 5,769,522), and that claims 22-25 are obvious over Koike in view of Hattersley (GB 2 281 802).

4. Key Claim Construction Positions

  • "deformities" (claims 1, 2, 18, 22, and 23): Petitioner argued that this term should be construed according to its express definition in the ’196 patent’s specification: "any change in the shape or geometry of a surface and/or coating or surface treatment that causes a portion of the light to be emitted from the backlight." This broad construction was central to mapping prior art elements like printed dots (Kojima) and dispersed particles (Koike) to the claims.
  • "light redirecting film" (claims 1 and 22): Petitioner again relied on the patent’s specification, proposing the construction: "a thin transparent or translucent optical film or substrate that redistributes the light passing through the film or substrate such that the distribution of the light exiting the films is directed more normal to the surface of the film or substrate."

5. Relief Requested

  • Petitioner requests institution of an inter partes review and cancellation of claims 1-25 of the ’196 patent as unpatentable.