KJ Pretech Co Ltd v. Innovative Display Technologies

1. Case Identification

• Case #: IPR2015-01867
• Patent #: 7,537,370
• Filed: September 11, 2015
• Petitioner(s): KJ. Pretech Co., Ltd.
• Patent Owner(s): Innovative Display Technologies LLC
• Challenged Claims: 1, 4-6, 9, 13, 29, and 47

2. Patent Overview

• Title: Light Emitting Panel Assemblies and Method of Making Same
• Brief Description: The ’370 patent describes light emitting panel assemblies, typically used as backlights for liquid crystal displays (LCDs). The technology involves a transparent panel member (a light guide) that receives light from a source at its edge and uses a pattern of "deformities" on its surfaces to extract and emit the light in a controlled distribution.

3. Grounds for Unpatentability

Ground 1: Obviousness over Kobayashi - Claims 1, 4, and 29 are obvious over Kobayashi.

• Prior Art Relied Upon: Kobayashi (Patent 5,408,388).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Kobayashi, a reference for a planar illuminating device, discloses all limitations of the challenged claims. The argument centered on a specific embodiment in Kobayashi (Fig. 6) which was not the primary focus of prior challenges against the ’370 patent. Petitioner asserted that this embodiment discloses an optical panel with prismatic cuts on its front surface and a "satin finish" comprising minute depressions (e.g., concave or hemispheric) on its rear surface. This combination allegedly meets the independent claim requirement for having light-extracting deformities of a different type on opposite sides of the panel. The variation of these deformities, such as varying the density of spot-shaped layers on the satin finish, was argued to meet the limitation of a pattern that varies along the panel's length.
  • Motivation to Combine (for §103 grounds): Not applicable as this is a single-reference ground. Petitioner contended that Kobayashi explicitly teaches and suggests the combination of features from its various disclosed embodiments into the single device shown in Fig. 6, making the claimed invention obvious.
  • Expectation of Success (for §103 grounds): Petitioner argued a POSITA would have had an expectation of success because Kobayashi explicitly teaches that its features are intended to increase luminance and uniformity, the same goals as the ’370 patent.

Ground 2: Obviousness over Kobayashi and Pristash - Claims 13 and 47 are obvious over Kobayashi in view of Pristash.

• Prior Art Relied Upon: Kobayashi (Patent 5,408,388) and Pristash (Patent 5,005,108).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground addressed claims 13 and 47, which additionally require a "transition region" to mix and spread light between the light source and the pattern of deformities. Petitioner asserted that while Kobayashi teaches the base light emitting panel assembly, it does not explicitly disclose this transition region, instead showing an air gap. Pristash, which relates to thin panel illuminators, was cited for its express disclosure of a solid, transparent "transition device" designed to efficiently couple and spread light from a source into a light emitting panel. Pristash further teaches that the transition device can have optical elements, such as a lens surface, to alter the light distribution.
  • Motivation to Combine (for §103 grounds): Petitioner argued a POSITA would combine these references as both address the same technical field (backlight assemblies) and share the objective of improving light efficiency. A POSITA would have been motivated to replace the air gap in Kobayashi's design with Pristash's explicit transition device to improve the efficiency of coupling light from the source into the light guide by reducing reflection at the air-plate interface.
  • Expectation of Success (for §103 grounds): Success would be expected because transition devices were known components used for the exact purpose of improving light coupling and distribution in such assemblies.

Ground 3: Obviousness over Suzuki - Claims 1, 4-5, 9, 13, 29, and 47 are obvious over Suzuki.

• Prior Art Relied Upon: Suzuki (JP H03-189679).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner contended that Suzuki alone renders all challenged claims obvious. Suzuki describes a surface light source device with a thin transparent light guide layer that uses an "embossed pattern" of projections or recesses to achieve uniform brightness. Petitioner argued Suzuki explicitly teaches forming these patterns on one or both sides of the light guide. Crucially, Suzuki discloses numerous different types of deformities (e.g., quadrangular-pyramid-shaped recesses, conical shapes, mixed projections) and expressly states that "all or some of these examples may also be employed in combination." This teaching allegedly made it obvious to use different types of deformities on the front and back surfaces of the light guide. Suzuki also discloses that the "projection area" or "pitch" of the embossed elements can be gradually changed with distance from the light source, meeting the variation requirement. For claims requiring a "transition region," Suzuki's teaching that the embossed pattern need not cover the entire surface was argued to create such a region.
  • Motivation to Combine (for §103 grounds): Not applicable as this is a single-reference ground. Petitioner argued a POSITA would simply follow the express teachings and combinations suggested within Suzuki to arrive at the claimed invention.
  • Expectation of Success (for §103 grounds): A POSITA would have had a high expectation of success, as Suzuki's stated objective is to provide a thin, light, and inexpensive device with high and uniform brightness by using the very combinations of features it describes.
• Additional Grounds: Petitioner asserted additional obviousness challenges, including Suzuki in view of Pristash (to further support the "transition region" limitation) and Suzuki in view of Murata (Patent 4,929,866) (to further support using different deformity types like recesses and projections on opposite sides).

4. Key Claim Construction Positions

• "deformities": Petitioner argued this term should be construed according to its express definition in the ’370 patent specification: "any change in the shape or geometry of the panel surface and/or coating or surface treatment that causes a portion of the light to be emitted."
• "transition region": Petitioner proposed construing this term to include any "region configured to transmit light [between the at least one input edge and the patterns of light extracting deformities to allow the light... to mix and spread]," citing both the patent's disclosure and a claim construction order from related district court litigation.

5. Relief Requested

• Petitioner requests the institution of an inter partes review and cancellation of claims 1, 4-6, 9, 13, 29, and 47 of the ’370 patent as unpatentable.