Hisense USA Corp v. Brightplus Ventures LLC

1. Case Identification

• Case #: IPR2023-01311
• Patent #: 8,177,382
• Petitioner(s): Hisense USA Corporation
• Patent Owner(s): Brightplus Ventures LLC
• Challenged Claims: 1-20

2. Patent Overview

• Title: Apparatus and Methods for Multiplanar Optical Diffusers and Display Panels for Using the Same
• Brief Description: The ’382 patent discloses a solid-state lighting device, typically for an LCD backlight, that uses a plurality of light-emitting diodes (LEDs) and a multi-plane light diffuser. The diffuser includes at least a first and a second diffusion plane positioned at different distances from the LEDs to homogenize the light.

3. Grounds for Unpatentability

Ground 1: Claims 1-3, 7-9, and 11-15 are obvious over Kobayashi

• Prior Art Relied Upon: Kobayashi (JP Publication # 2007-329016).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Kobayashi, a single reference, discloses every limitation of the challenged independent claims. Kobayashi teaches a backlight unit for a display device using LEDs as the light source and at least two diffusion planes (diffuser plates 4 and 5) positioned at different distances from the LEDs. Critically, Kobayashi explicitly discloses the key limitation that served as the basis for allowance: a functional relationship between the distance from the LEDs to the first diffusion plane ("first distance") and the distance between adjacent LEDs ("third distance"). Kobayashi defines a preferred ratio of "c / b," where 'c' is the first distance and 'b' is the third distance, thereby teaching that the first distance is a function of the third distance.
  • Key Aspects: This ground asserted that the primary prior art reference alone teaches the very feature the patent examiner identified as lacking in the prior art during prosecution, rendering the claims obvious.

Ground 2: Claims 10 and 16 are obvious over Kobayashi in view of Kirita

• Prior Art Relied Upon: Kobayashi (JP Publication # 2007-329016) and Kirita (Application # 2006/0050198).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground built upon the Kobayashi reference to address dependent claims 10 and 16, which recite a diffuser plate that includes a "light filter color." While Kobayashi provides the base backlight structure with multiple diffusion planes, it does not expressly disclose a color-selective filter. Kirita, which also discloses a backlight assembly for a display, remedies this by teaching a "light selective transmission filter" used to improve the color properties of the display.
  • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA) would combine Kirita’s color filter with Kobayashi’s backlight system to achieve predictable benefits. Specifically, a POSITA would be motivated to improve the color purity, expand the color reproduction range, and improve the NTSC ratio of the display disclosed in Kobayashi by incorporating the known color filter technology taught by Kirita.
  • Expectation of Success: The combination involved applying a known technique (a color filter) to a similar device (a backlight system) to achieve a predictable improvement in image quality, leading to a high expectation of success.

Ground 3: Claims 1-2, 7-8, and 11-15 are obvious over Schiavoni in view of Lim

• Prior Art Relied Upon: Schiavoni (WO 2008/025909) and Lim (Application # 2002/0071288).

• Core Argument for this Ground:

  • Prior Art Mapping: This ground presented an alternative invalidity theory using a different set of primary references. Schiavoni was argued to be a suitable primary reference, as it discloses an optical system for backlighting with LEDs and a multi-plane diffuser comprising a first optical element and a second planar diffuser at different distances. However, Schiavoni does not explicitly disclose the functional relationship between the LED-to-diffuser distance and the inter-LED distance. Lim was argued to supply this missing element, as it expressly teaches a relationship "between a diffusion plate and a lamp in accordance with the distance between lamps," noting that a smaller interval between lamps allows for a narrower interval to the diffusion plate.
  • Motivation to Combine: A POSITA would combine the teachings of Lim with the system in Schiavoni as a matter of routine design choice to optimize performance. Specifically, incorporating Lim's disclosed spacing relationships would enable the design of a thinner overall backlight structure with fewer diffuser plates, a well-known goal in the field of display design.
  • Expectation of Success: The proposed modification was argued to be nothing more than modifying the positioning of elements already described in Schiavoni according to a known distance relationship taught by Lim, which would have been a predictable design modification for a POSITA.

• Additional Grounds: Petitioner asserted numerous other obviousness grounds. These included combining Kobayashi with Tabito (Application # 2007/0103908) to add teachings of diffuser supports; combining Kobayashi, Tabito, and Onishi (Application # 2005/0243551) to add teachings of structured diffusers with extrusion peaks/grooves; and further combining those references with Epstein (Application # 2005/0024754) to add teachings of crossed linear prismatic lenselets. Similar combinations were asserted using Schiavoni as the primary reference.

4. Arguments Regarding Discretionary Denial

• Petitioner argued that discretionary denial under §314(a) based on Fintiv factors would be inappropriate. The parallel district court litigation was asserted to be in its very early stages, with no trial date set, no Markman hearing scheduled, and significant discovery yet to occur. Petitioner contended that a Final Written Decision in the inter partes review (IPR) would likely issue well before any potential trial date, and that the petition was filed expeditiously after the patent owner identified the asserted claims. Petitioner also argued that denial under §325(d) was inappropriate because none of the prior art references relied upon in the petition were cited in a substantive rejection during prosecution.

5. Relief Requested

• Petitioner requests institution of an IPR and cancellation of claims 1-20 of Patent 8,177,382 as unpatentable.