Guardian Glass LLC v. AGC Inc

1. Case Identification

• Case #: IPR2021-00173
• Patent #: 8,075,983
• Filed: November 4, 2020
• Petitioner(s): Guardian Glass, LLC
• Patent Owner(s): AGC, Inc.
• Challenged Claims: 1, 4-8, and 11-38

2. Patent Overview

• Title: Laminated Glass For Vehicle
• Brief Description: The ’983 patent is directed to a laminated glass structure for vehicle windshields, particularly for use in a Head-Up Display (HUD) system. The patent purports to solve an optical distortion problem by using a multilayer interlayer with specific minimum thickness requirements for its outer layers.

3. Grounds for Unpatentability

Ground 1: Claims 1, 4-8, and 11-38 are obvious over Nakamura and Sauer.

• Prior Art Relied Upon: Nakamura (Certified translation of JP 2004-175593A) and Sauer (Application # 2002/0086141).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that the combination of Nakamura and Sauer taught all limitations of the independent claims. Sauer disclosed a laminated glass window for a HUD system comprising a multilayered intermediate layer (interlayer) with a wedge-shaped cross-section to prevent double imaging. This interlayer included two outer thermoplastic sheets (first resin layers) and a central functional support sheet (second resin layer). Nakamura disclosed a laminated glass for automotive windows with a similar three-layer acoustic interlayer (hard-soft-hard) and taught that the outer hard layers ("intermediate films") must have a thickness of at least 0.3 mm to ensure strength and block UV rays.
  • Motivation to Combine: A Person of Ordinary Skill in the Art (POSA) would combine these analogous references to improve upon known designs. A POSA would modify Nakamura's acoustic interlayer with Sauer's wedge-shaped geometry to make it suitable for a HUD application, thereby gaining both acoustic benefits and proper HUD imaging. Alternatively, a POSA would improve Sauer's HUD interlayer by incorporating the specific minimum thickness (0.3 mm) and superior acoustic materials taught by Nakamura to enhance strength, durability, and sound insulation.
  • Expectation of Success: A POSA would have a reasonable expectation of success in combining these known elements for automotive windshields, as it involved applying established principles and components within the same field of art to achieve predictable results.

Ground 2: Claims 1, 4-8, and 11-38 are obvious over Nakamura and Sauer in view of Miyai.

• Prior Art Relied Upon: Nakamura (JP 2004-175593A), Sauer (Application # 2002/0086141), and Miyai (EP Application # 0710545 A1).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground builds upon the combination of Nakamura and Sauer, which established the basic structure of a wedge-shaped, multilayer acoustic interlayer for a HUD. Petitioner argued that a known issue with such interlayers is optical distortion caused by embossing on the outer surfaces, a process used to aid in manufacturing. Miyai directly addressed this exact problem. Miyai taught that for a multilayer acoustic interlayer, "minute uneven deformations" from embossing can transfer to the inner layer interfaces, causing "so-called optical distortion." Miyai explicitly taught that increasing the thickness of the "outmost resin film" to a range of 200 to 720 micrometers (0.2 mm to 0.72 mm) solves this problem, and provided examples where a thickness of 0.3 mm or more prevented any detected optical distortion.
  • Motivation to Combine: After combining Nakamura and Sauer, a POSA would be faced with the known problem of potential optical distortion resulting from the necessary embossing step. A POSA would have been motivated to consult prior art like Miyai, which specifically identifies and provides a solution for this exact issue in the context of acoustic multilayer interlayers for vehicles. Miyai provides the missing link: the express rationale for using a minimum outer layer thickness of 0.3 mm to prevent optical distortion, the very problem the ’983 patent claims to have solved.
  • Expectation of Success: A POSA would have expected Miyai's solution to work successfully in the combined Nakamura/Sauer structure, as Miyai's teachings were directly applicable to the same type of product (acoustic multilayer interlayers) and the same technical problem (embossing-induced optical distortion).

4. Key Claim Construction Positions

• "thickness capable of preventing optical distortion": Petitioner argued this term should be construed to mean "a thickness of at least 0.3 mm." This construction is based on repeated, explicit statements in the ’983 patent's specification and the Patent Owner’s own arguments during a prior ex parte reexamination (EPR), where this thickness was presented as "the solution" to the distortion problem.
• "embossed concave convex profile": Petitioner asserted this term should be interpreted as an "embossed outer surface of the interlayer." This construction is critical for linking the problem described in the patent to the problem explicitly solved by the prior art, particularly Miyai, which addresses distortion originating from surface embossing.

5. Arguments Regarding Discretionary Denial

• Petitioner argued that the Board should not exercise discretionary denial under §314(a) or §325(d) based on a prior EPR proceeding. Petitioner asserted that the General Plastic factors favored institution because Petitioner was not involved in the prior EPR and this petition relies on new prior art and arguments. Specifically, the primary reference Nakamura was never cited or considered during the original prosecution or the EPR.
• Under the Advanced Bionics framework, Petitioner argued that the USPTO committed a material error during the EPR by failing to consider the proposed combination of Nakamura and Sauer. Furthermore, Petitioner alleged the Patent Owner made misleading statements about Miyai's relevance, incorrectly characterizing it as only applying to "transmitted distortion" and not to HUDs or acoustic interlayers, despite Miyai's explicit text to the contrary. The new evidence and arguments presented, including expert declarations, were contended to show that the prior art teaches the very solution the examiner found lacking during reexamination.

6. Relief Requested

• Petitioner requested institution of an inter partes review and cancellation of claims 1, 4-8, and 11-38 of the ’983 patent as unpatentable.