Hisense USA Corp v. Light Guide Innovations LLC

1. Case Identification

• Case #: IPR2025-01538
• Patent #: 8,267,537
• Filed: September 16, 2025
• Petitioner(s): Hisense USA Corporation
• Patent Owner(s): Light Guide Innovations LLC
• Challenged Claims: 1-20

2. Patent Overview

• Title: Backlight Unit and Display Device
• Brief Description: The ’537 patent relates to a backlight unit for display devices. The invention describes a structure intended to allow for easy separation and replacement of light emitting diode (LED) modules from a supporting case by using a flexible "bending part" to guide and partially fix the module, and a separate "fixing part" to fully secure it.

3. Grounds for Unpatentability

Ground 1: Claims 1, 3-5, 8-9, 11-14, 16-17, 19, and 20 are obvious over Liu in view of the knowledge of a POSITA.

• Prior Art Relied Upon: Liu (Taiwan Patent # TWI248538B).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Liu discloses all elements of the challenged claims. Liu describes a backlight module with a detachable board (the claimed LED module) mounted on an elastic backboard (the claimed case). Petitioner asserted that Liu’s integrally formed, elastic "stamped protrusion part" (308), which uses clamping force to "tightly hold" the board, performs the function of the claimed bending part that guides and fixes an end of the module. Liu’s separate bolt (314) and nut (316) assembly, which fastens the other end of the board, was mapped to the claimed fixing part. Petitioner contended that various dependent claim limitations are also taught by different embodiments or figures within Liu or would have been obvious modifications to a POSITA.
  • Motivation to Combine (for §103 grounds): The argument centered on Liu as a primary reference, asserting that its teachings, combined with the general knowledge of a person of ordinary skill in the art (POSITA), rendered the claims obvious. The motivation was inherent in Liu's own disclosure, which aimed to solve the same problem as the ’537 patent: creating a system for easily installing and replacing LED modules without complex fasteners.
  • Expectation of Success (for §103 grounds): A POSITA would have had a high expectation of success as the argument relied on applying the direct teachings of a single reference to solve a known problem in the art.

Ground 2: Claims 2, 6, 7, 15, and 18 are obvious over Liu in view of Roberts.

• Prior Art Relied Upon: Liu (Taiwan Patent # TWI248538B) and Roberts (Application # 2007/0247414).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner asserted that Liu provides the foundational structure of a backlight with a detachable LED module, as detailed in Ground 1. Roberts was introduced to teach specific features related to the internal construction and optical performance of the LED module itself. Specifically, Roberts disclosed using a printed circuit board (PCB) for mounting LEDs, covering the LEDs with an encapsulant (mold part), and using a reflective sheet with openings over the LEDs to improve light uniformity and recycling. These features correspond directly to the limitations of claims 2, 6, 7, 15, and 18.
  • Motivation to Combine (for §103 grounds): A POSITA would combine Roberts’s teachings with Liu’s system to improve its performance. Petitioner argued that incorporating a PCB, encapsulant, and reflective sheet were well-known techniques for enhancing the electrical connectivity, light emission quality, and overall efficiency of LED backlight modules. A POSITA would have been motivated to apply these known improvements to Liu’s basic, serviceable design.
  • Expectation of Success (for §103 grounds): Success would have been reasonably expected because the combination involved applying conventional and predictable components to an existing backlight structure to achieve known benefits.

Ground 3: Claim 10 is obvious over Liu in view of Liu-660.

• Prior Art Relied Upon: Liu (Taiwan Patent # TWI248538B) and Liu-660 (Application # 2006/0187660).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground focused specifically on claim 10, which requires the bending part to be formed with a member separated from the case. While Liu teaches a bending part that is integrated with the case (as argued for claim 9), the related Liu-660 reference, by the same inventor, discloses an alternative fastening mechanism. Liu-660 teaches using a separate "rigid metal board" (23) that laps over adjacent LED modules to exert a compressing force and fasten them to the backboard. This separate board was asserted to teach the "member separated from the case" limitation.
  • Motivation to Combine (for §103 grounds): A POSITA would combine the references because they offer alternative solutions to the same problem from the same inventor. Petitioner argued it would have been a simple substitution to replace Liu's integrated protrusion part with Liu-660's separate rigid board to achieve the same function of clamping the LED module. This would have been an obvious design choice to one of ordinary skill.
  • Expectation of Success (for §103 grounds): There was a high expectation of success, as this combination represented a simple substitution of one known mechanical fastening element for another to perform the same function in a similar device.

4. Arguments Regarding Discretionary Denial

• Petitioner stipulated that, if the IPR is instituted, it will not pursue in co-pending litigation any ground raised or that could have been reasonably raised in the petition. This stipulation, made under the framework of Sotera Wireless, Inc. v. Masimo Corp., was presented to argue against a discretionary denial of institution under the Fintiv factors by mitigating concerns about parallel proceedings.

5. Relief Requested

• Petitioner requests institution of an inter partes review and cancellation of claims 1-20 of Patent 8,267,537 as unpatentable.