GriMCO Inc v. Principal Lighting Group LLC

1. Case Identification

• Case #: IPR2021-00968
• Patent #: 9,311,835
• Filed: May 17, 2021
• Petitioner(s): Grimco, Inc.
• Patent Owner(s): Principal Lighting Group, LLC
• Challenged Claims: 1-20

2. Patent Overview

• Title: Retrofit LED Lamp for Internally-Lighted Signs
• Brief Description: The ’835 patent discloses a retrofit light emitting diode (LED) lamp designed to replace gas-discharge lamps in internally-lighted signs. The invention comprises an elongate support member holding multiple LED units, with end caps at each end that feature mechanical coupling elements made of electrically insulative material to engage existing sockets without creating an electrical connection.

3. Grounds for Unpatentability

Ground 1: Obviousness over Huang and Zimmerman - Claims 1, 8-10, 13, 15-17, and 19 are obvious over Huang in view of Zimmerman.

• Prior Art Relied Upon: Huang (Patent 7,441,922) and Zimmerman (Patent 8,083,373).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued Huang taught an LED lamp tube for replacing fluorescent bulbs, which included an elongate circuit board, LEDs, and end caps. Huang's end caps frictionally engage the circuit board and possess pins for mechanically mounting the tube into existing fluorescent bulb holders, while power is supplied via a separate power cord. Zimmerman was cited for its disclosure of single-pin and bi-pin adapters for mounting LED assemblies into pre-existing receptacles, with the adapters explicitly made of "electrically-insulating material" to guard against electrical shock.
  • Motivation to Combine: A person of ordinary skill in the art (POSITA) would combine Zimmerman's teaching of electrically-insulating material with Huang's end cap and pin design. The motivation was to improve the safety of Huang's lamp by reducing the risk of electrical shock and to lower manufacturing costs compared to using conductive materials.
  • Expectation of Success: Petitioner asserted that combining these known elements—an LED lamp structure from Huang and an insulating material from Zimmerman—would predictably result in a safer and more cost-effective lamp.

Ground 2: Obviousness over Huang, Zimmerman, and Villard - Claims 2, 3, 6, 7, and 11 are obvious over Huang in view of Zimmerman and Villard.

• Prior Art Relied Upon: Huang (Patent 7,441,922), Zimmerman (Patent 8,083,373), and Villard (Application # 2009/0316408).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground builds upon the combination of Huang and Zimmerman. Villard was introduced for its disclosure of a heat-spreading mount for LEDs having an I-beam cross-section, including a web portion and flange portions. Petitioner mapped this structure to the limitations of dependent claims requiring an I-beam support member.
  • Motivation to Combine: A POSITA would be motivated to modify the elongate support member of Huang with the I-beam structure from Villard to improve thermal management. Heat dissipation is a known challenge for LEDs, and Villard's heat spreader design would cost-effectively dissipate heat, thereby improving the performance, reliability, and longevity of the LED lamp.
  • Expectation of Success: Incorporating a known heat-spreading structure like Villard's into an LED lamp like Huang's was argued to be a straightforward modification with a high expectation of success in improving heat dissipation.

Ground 10: Obviousness over Withers, Hoover, and Zimmerman - Claims 1, 8-10, 13, 15-17 and 19 are obvious over Withers in view of Hoover and Zimmerman.

• Prior Art Relied Upon: Withers (Application # 2010/0270925), Hoover (Patent 7,360,316), and Zimmerman (Patent 8,083,373).

• Core Argument for this Ground:

  • Prior Art Mapping: Petitioner presented Withers as an alternative primary reference disclosing an LED light tube with "dummy" end caps and pins for purely physical, non-electrical connection to existing sockets, with power supplied separately. Hoover was cited for teaching an end cap with flanges designed to engage an I-beam body, providing a secure frictional connection. Zimmerman was again used for its teaching of electrically insulating materials for adapters.
  • Motivation to Combine: A POSITA would be motivated to modify the end caps of Withers to include the flanges taught by Hoover to achieve a more secure frictional engagement with the lamp's support member. Concurrently, a POSITA would make Withers' end caps and pins from the electrically insulating material taught by Zimmerman for the same reasons of improved safety and reduced cost as in Ground 1.
  • Expectation of Success: Petitioner contended that combining a known secure connection mechanism (Hoover's flanges) with a retrofit LED tube (Withers) and using a known insulating material (Zimmerman) would predictably result in a more robust, safer, and cheaper product.

• Additional Grounds: Petitioner asserted numerous additional obviousness challenges based on combinations of the primary references Huang or Withers with various secondary references, including Timmermans (for an I-beam circuit board), Cummings (for fixed and spring-loaded mounts), Nall (for cutting a lighting system to fit), and Reed (for replacing standard mounts with plate brackets).

4. Key Claim Construction Positions

• "Frictionally Engage": Petitioner proposed this term should be construed to mean "element A contacts element B such that it is a frictional force between elements A and B that retains the positions of elements A and B relative to each other." Petitioner argued this construction is critical because the term was added during prosecution to overcome prior art (Yang) that disclosed a broader range of connections, such as mechanical or adhesive-based attachments. The amendment specifically to "frictionally engage" was intended to distinguish the invention by requiring a retention force based on friction between the end caps and the support member.

5. Arguments Regarding Discretionary Denial

• Against §314(a) Denial (Fintiv Factors): Petitioner argued against discretionary denial because the co-pending district court litigation was in its early stages. The petition was filed less than six months after the complaint was served, no significant discovery had occurred, and the trial date was over a year away and likely to be rescheduled. Petitioner also stated its intent to seek a stay of the litigation and to file a stipulation that it would not pursue in court any invalidity grounds raised or that could have been reasonably raised in the IPR.
• Against §325(d) Denial: Petitioner contended that denial was not warranted because the primary prior art references, Huang and Withers, were never considered during the patent's original prosecution. Although Zimmerman was cited by the examiner, it was not applied for the specific teaching relied upon in the petition (i.e., making end caps from electrically insulating material). Therefore, Petitioner argued the Board would be considering the art and arguments in a new light.

6. Relief Requested

• Petitioner requests the institution of an inter partes review and the cancellation of claims 1-20 of Patent 9,311,835 as unpatentable.