TCL Electronics Holdings Ltd v. LG Electronics Inc

1. Case Identification

• Case #: IPR2023-00239
• Patent #: 9,080,740
• Filed: November 29, 2022
• Petitioner(s): TCL Electronics Holdings Ltd. and related entities
• Patent Owner(s): LG Electronics Inc.
• Challenged Claims: 1-31

2. Patent Overview

• Title: Planar Lighting Device and Display Device
• Brief Description: The ’740 patent describes a direct-type, planar backlight assembly for a display device. The invention purports to solve uneven illumination by using a reflection sheet with inclined peripheral portions that feature a hole pattern, where at least two of the holes are different in size to regulate reflectance.

3. Grounds for Unpatentability

Ground 1: Obviousness over Yokota in view of Matsumoto - Claims 1-3, 7-29, and 31

• Prior Art Relied Upon: Yokota (Application # 2012/0069248) and Matsumoto (Application # 2012/0287347).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Yokota discloses all elements of the independent claims except for the limitation that at least two through holes in the reflection layer's hole pattern are different in size. Yokota teaches a direct-type backlight with a reflection sheet having inclined peripheral surfaces. To address uneven luminance at the edges, Yokota discloses applying a "reflection reduction treatment" to these inclined surfaces, which can be an arrangement of holes (apertures) or dots of light-absorbing ink, and teaches that the size of these elements can be optimized. Matsumoto was cited to address the missing element. Matsumoto tackles the same problem of "dark portions" and uneven brightness in a direct-type backlight by applying a pattern of light-absorbing dots of two different sizes (small and large) to its reflection sheet to selectively reduce reflectance.
  • Motivation to Combine: A POSITA would combine these references because they address the identical problem of non-uniform illumination in direct-type backlights. Yokota expressly teaches that holes and dots are interchangeable for its reflection reduction treatment and that their size can be optimized. A POSITA, seeking to implement Yokota's solution, would have looked to analogous art like Matsumoto, which teaches using different sized dots to create a graduated reflection reduction effect. Applying Matsumoto’s teaching of using multiple sizes to Yokota’s holes was argued to be a predictable combination of known elements to achieve a more optimized and uniform backlight.
  • Expectation of Success: A POSITA would have had a reasonable expectation of success in modifying Yokota's holes to have different sizes based on Matsumoto's teachings. The combination would predictably result in more granular control over light reflectance, thereby achieving the desired goal of improved illumination uniformity.

Ground 2: Obviousness over Yokota, Matsumoto, and Ha - Claim 30

• Prior Art Relied Upon: Yokota (Application # 2012/0069248), Matsumoto (Application # 2012/0287347), and Ha (Application # 2011/0013119).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground built upon the combination of Yokota and Matsumoto to address claim 30, which further requires that the inclination of the reflection sheet's second surface is "about a right angle" with respect to the first surface. While Yokota and Matsumoto teach inclined peripheral surfaces, Ha was introduced because it explicitly discloses a backlight assembly with a reflection plate having peripheral portions inclined at "about a right angle" to the central portion.
  • Motivation to Combine: Petitioner contended that modifying the angle of inclination of the reflector in the Yokota/Matsumoto combination to be "about a right angle" as taught by Ha would have been a simple design choice for a POSITA. Since all three references operate in the same technical field to achieve uniform lighting, incorporating a known reflector geometry from Ha into the primary combination was presented as an obvious modification to achieve a known function.

Ground 3: Obviousness over Yokota in view of Kim - Claims 4-6

• Prior Art Relied Upon: Yokota (Application # 2012/0069248) and Kim (Patent 7,275,852).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground addressed claims 4-6, which depend from claim 1 and add limitations requiring a "lower cover having grooves" where the circuit substrates are located. Yokota discloses mounting circuit substrates on a chassis. Kim was introduced because it teaches a backlight unit where elongated LED modules are supported in "elongated recesses or grooves" within a module supporter on the lower chassis.
  • Motivation to Combine: A POSITA would have been motivated to modify Yokota's design to include the grooved mounting structure from Kim. Both disclosures relate to mounting LED strips in planar backlights. Using Kim's grooves would result in a more uniform light source because the circuit substrates would sit below the principal surface of the reflector sheet, a known technique for improving uniformity. This was argued to be a routine design choice between known mounting structures.

4. Arguments Regarding Discretionary Denial

• Petitioner argued that the Board should not exercise discretionary denial under Fintiv. It was asserted that the district court trial date in a parallel proceeding was scheduled for well after the statutory deadline for a Final Written Decision (FWD). Petitioner also submitted a stipulation that it would not pursue in the parallel proceeding any invalidity grounds raised or that could have been reasonably raised in the IPR.
• Petitioner further contended that denial under 35 U.S.C. §325(d) was inappropriate because the prior art references and arguments presented in the petition were never before the Examiner during the original prosecution of the ’740 patent.

5. Relief Requested

• Petitioner requested the institution of an inter partes review and the cancellation of claims 1-31 of Patent 9,080,740 as unpatentable.