Home Depot USA Inc v. Lynk Labs Inc

1. Case Identification

• Case #: IPR2021-01369
• Patent #: 10,492,251
• Filed: August 18, 2021
• Petitioner(s): Home Depot U.S.A., Inc.
• Patent Owner(s): Lynk Labs, Inc.
• Challenged Claims: 1, 11, and 13

2. Patent Overview

• Title: AC Light Emitting Diode and AC LED Drive Methods and Apparatus
• Brief Description: The ’251 patent relates to light-emitting diode (LED) lighting systems and driver circuits for powering them. The technology covers methods and apparatus for driving LEDs using AC or DC voltage sources.

3. Grounds for Unpatentability

Ground 1: Obviousness over Deese, Kuo, and Obeck - Claim 1 is obvious over Deese in view of Kuo and Obeck.

• Prior Art Relied Upon: Deese (Patent 5,457,450), Kuo (Patent 6,019,493), and Obeck (Patent 5,014,052).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Deese, an LED traffic lighting system, discloses the foundational elements of claim 1, including an LED driver with an input/output and an LED circuit. Petitioner asserted that Kuo, which also discloses an LED traffic light, teaches coating the LED circuit board with a reflective substance to increase brightness, thereby satisfying the "reflective substrate" limitation. Finally, Petitioner alleged that Obeck, another traffic light control system, teaches incorporating a data receiver into a signal controller to allow for traffic signal preemption via data from a transmission line or antenna.
  • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA) would combine Deese and Kuo to improve the brightness of the Deese system, as Kuo expressly teaches using a reflective coating to solve the problem of wasted light. A POSITA would further incorporate Obeck's data receiver into Deese's conventional controller to add the well-known and advantageous functionality of emergency vehicle preemption, which Obeck describes in detail. All three references are in the analogous art of traffic lighting systems.
  • Expectation of Success: A POSITA would have a reasonable expectation of success because the proposed modifications involve combining known elements for their predictable purposes: adding a reflective coating to increase brightness and adding a data receiver to enable remote control.

Ground 2: Obviousness over Okuno and Teshima - Claim 11 is obvious over Okuno in view of Teshima.

• Prior Art Relied Upon: Okuno (Patent 4,298,869) and Teshima (Patent 4,271,408).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued Okuno discloses a multi-color LED traffic light system with many core features of claim 11, including an LED circuit array with red, yellow, and green circuits, an active current limiting device, an AC-to-DC driver, and LEDs doped with impurities to produce different colors. However, Okuno does not detail the circuitry for a single, combined multi-color light. Teshima was argued to supply this missing detail, teaching a combined traffic light implemented as an LED circuit array with selectable red, yellow, and green circuits driven by a single LED driver.
  • Motivation to Combine: A POSITA implementing Okuno’s combined multi-color traffic light would be motivated to look to Teshima for a specific circuit implementation. Teshima’s use of a single, switched driver to power different colored LED circuits was more efficient and less redundant than using separate drivers. This combination directly addresses the implementation gap in Okuno.
  • Expectation of Success: Using a single driver to switch between and drive an array of LED circuits, as taught by Teshima, was a well-known technique in LED lighting systems, leading to a high expectation of success.

Ground 3: Obviousness over Okuno, Teshima, and Butterworth - Claim 11 is obvious over Okuno in view of Teshima and Butterworth.

• Prior Art Relied Upon: Okuno (Patent 4,298,869), Teshima (Patent 4,271,408), and Butterworth (Patent 5,847,507).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground builds upon the Okuno/Teshima combination by adding Butterworth to address claim 11’s limitation of a "coated or doped" LED. While Okuno teaches creating color by doping the semiconductor material, Butterworth teaches a more modern and efficient method: coating a blue LED with a phosphor- or dye-infused epoxy lens to convert the blue light into other colors (e.g., green, yellow, red).
  • Motivation to Combine: Petitioner argued that Butterworth, from 1997, expressly identifies the older doping method (used in Okuno, from 1979) as less efficient. A POSITA would have been motivated to replace Okuno’s outdated doping technique with Butterworth’s superior coated-LED technology to achieve better efficiency, color consistency, and manufacturing yield—all advantages explicitly taught by Butterworth.
  • Expectation of Success: A POSITA would have a reasonable expectation of success in using Butterworth’s coated LEDs, as the technique was well-established by the ’251 patent’s priority date and involved substituting a known, improved component into the established Okuno/Teshima circuit design.
• Additional Grounds: Petitioner asserted that claim 13 is obvious over the combination of Deese and Kuo. This argument relied on the same rationale for combining these two references as presented in Ground 1.

4. Arguments Regarding Discretionary Denial

• Petitioner presented substantial arguments that discretionary denial under 35 U.S.C. §314(a) based on Fintiv factors would be inappropriate. The core arguments were that the parallel district court litigation was in its infancy, with a distant and tentative trial date set more than a year away.
• Petitioner further stipulated that, if the inter partes review (IPR) is instituted, it would not pursue the same instituted grounds or grounds based on the same primary reference in the district court litigation, thus mitigating concerns of duplicative efforts.
• Petitioner also argued that denial under §325(d) was unwarranted because none of the asserted prior art references were considered during the original prosecution of the ’251 patent, and the references establish a strong case of unpatentability.

5. Relief Requested

• Petitioner requests institution of IPR and cancellation of claims 1, 11, and 13 of the ’251 patent as unpatentable.