DCT

2:25-cv-00051

Light Guide Innovations LLC v. Hisense Co Ltd

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 2:25-cv-00051, E.D. Tex., 01/17/2025
  • Venue Allegations: Plaintiff alleges venue is proper because the Defendants are foreign companies that may be sued in any judicial district and have committed acts of patent infringement within the Eastern District of Texas.
  • Core Dispute: Plaintiff alleges that Defendant’s televisions and displays, including various LCD, LED, QLED, and MINI-LED models, infringe sixteen patents related to LED backlight assemblies, lenses, and components.
  • Technical Context: The patents relate to the design and construction of LED backlight units, which are fundamental components for illuminating the liquid crystal panels in modern flat-screen televisions and displays.
  • Key Procedural History: The complaint alleges that many of the asserted patents were originally developed by LG Innotek Co., Ltd. and that Defendants had knowledge of the patents at least since the time they were publicized during a sale from LG Innotek to Suzhou Lekin Semiconductor.

Case Timeline

Date Event
2006-08-24 U.S. Patent No. 7,936,415 Priority Date
2007-11-06 U.S. Patent No. 7,922,380 Priority Date
2009-11-19 U.S. Patent No. 8,052,307 Priority Date
2009-11-19 U.S. Patent No. 8,213,093 Priority Date
2009-11-19 U.S. Patent No. 8,506,122 Priority Date
2009-11-19 U.S. Patent No. 8,616,729 Priority Date
2009-11-19 U.S. Patent No. 9,534,744 Priority Date
2009-11-20 U.S. Patent No. 8,395,183 Priority Date
2009-11-20 U.S. Patent No. 8,823,048 Priority Date
2009-11-20 U.S. Patent No. 9,638,378 Priority Date
2009-11-20 U.S. Patent No. 10,030,823 Priority Date
2010-05-13 U.S. Patent No. 8,562,200 Priority Date
2011-04-12 U.S. Patent No. 7,922,380 Issued
2011-05-03 U.S. Patent No. 7,936,415 Issued
2011-11-08 U.S. Patent No. 8,052,307 Issued
2012-07-03 U.S. Patent No. 8,213,093 Issued
2012-08-07 U.S. Patent No. 8,237,352 Issued
2012-09-18 U.S. Patent No. 8,267,537 Issued
2013-03-12 U.S. Patent No. 8,395,183 Issued
2013-07-09 U.S. Patent No. 8,480,778 Issued
2013-08-13 U.S. Patent No. 8,506,122 Issued
2013-10-22 U.S. Patent No. 8,562,200 Issued
2013-12-31 U.S. Patent No. 8,616,729 Issued
2014-05-13 U.S. Patent No. 8,723,411 Issued
2014-09-02 U.S. Patent No. 8,823,048 Issued
2017-01-03 U.S. Patent No. 9,534,744 Issued
2017-05-02 U.S. Patent No. 9,638,378 Issued
2018-07-24 U.S. Patent No. 10,030,823 Issued
2023-01-01 Hisense tracks sales and growth of Accused Products (approx.)
2025-01-17 Complaint Filing Date

II. Technology and Patent(s)-in-Suit Analysis

U.S. Patent No. 7,936,415 - "Light Source Apparatus And Liquid Crystal Display Having The Same," Issued May 3, 2011

The Invention Explained

  • Problem Addressed: The patent addresses the need for improved mechanical and electrical connection structures for modular LED substrates used in backlight units, aiming to enhance reliability and simplify manufacturing (Compl. ¶29; ’415 Patent, col. 1:26-33).
  • The Patented Solution: The invention describes a light source apparatus where multiple LED "module substrates" are connected in series. The final module substrate in the series is connected back to the start via a "termination connecting substrate," which creates a "closed loop circuit" (Compl. ¶48; ’415 Patent, col. 3:37-46, FIG. 8). This modular, looped design allows for electrical connection between substrates without requiring an additional, separate module substrate (’415 Patent, col. 1:63-66).
  • Technical Importance: This approach suggests a method to construct large, reliable LED arrays for backlights from smaller, standardized modules while ensuring robust electrical connectivity throughout the assembly (Compl. ¶29).

Key Claims at a Glance

  • The complaint asserts infringement of at least Claim 1 (Compl. ¶47).
  • Independent Claim 1 requires:
    • at least one module substrate comprising connecting terminals at both side ends thereof;
    • a light emitting diode on the module substrate; and
    • a plurality of connecting substrates connected to the connecting terminals of the module substrate,
    • wherein the connecting substrate comprises a termination connecting substrate, by which the connecting terminal provided at one end of a final module substrate of the module substrates is prepared as a closed loop circuit.
  • The complaint does not explicitly reserve the right to assert dependent claims.

U.S. Patent No. 7,922,380 - "Light Unit And Display Device Having The Same," Issued April 12, 2011

The Invention Explained

  • Problem Addressed: The patent background describes the general structure of LCD backlights and the need for improved designs, with the summary indicating a focus on modules with improved heat conduction properties (Compl. ¶32; ’380 Patent, col. 1:20-33).
  • The Patented Solution: The invention discloses a light unit with a specific structural arrangement of components designed to manage heat and light. It comprises a light guide member, a flexible printed circuit board (PCB) with light-emitting devices, a reflection sheet, a housing, and a metal plate attached to the back of the PCB. A key feature is that the flexible PCB has a first portion disposed between the metal plate and the light guide member and a second portion disposed between the reflection sheet and the housing (’380 Patent, Abstract; col. 4:59-67).
  • Technical Importance: This layered construction suggests a method for integrating a flexible PCB into a backlight assembly in a way that facilitates heat transfer from the LEDs to the metal plate and housing while properly positioning the light-emitting components (Compl. ¶32).

Key Claims at a Glance

  • The complaint asserts infringement of at least Claim 1 (Compl. ¶60).
  • Independent Claim 1 requires:
    • a light guide member outputting surface light upward;
    • a board disposed to a first side of the light guide member;
    • a plurality of light-emitting devices mounted on a first side of the board;
    • a reflection sheet under the light guide member;
    • a housing receiving the light guide member, light-emitting devices, board, and reflection sheet;
    • a metal plate attached to a second side of the board and a first side of the housing;
    • wherein the board is a flexible PCB that includes a first portion (between the metal plate and light guide member) and a second portion (between the reflection sheet and housing), with the second portion including line patterns connected to the light-emitting devices.
  • The complaint does not explicitly reserve the right to assert dependent claims.

U.S. Patent No. 8,562,200 - "Lighting Module, Backlight Unit, And Display Device Including The Same," Issued October 22, 2013

  • Technology Synopsis: The patent describes a lighting module with at least one "guide protrusion" on the surface of the substrate. The protrusion includes a pin and a cap, with the pin's height being less than that of the light-emitting diodes, suggesting a feature for alignment or protection of optical components (Compl. ¶¶30, 81).
  • Asserted Claims: At least Claim 1 (Compl. ¶81).
  • Accused Features: The complaint alleges that the Accused Products contain guides on the LED strips that function as the claimed guide protrusions (Compl. ¶84).

U.S. Patent No. 8,506,122 - "Lens And Light Emitting Apparatus Having The Same," Issued August 13, 2013

  • Technology Synopsis: The patent relates to a light-emitting apparatus with a lens having a specific geometry. The lens body features a first recess on its top surface and a second recess on its bottom surface, and is supported by a lens support that spaces it from the substrate (Compl. ¶¶34, 95).
  • Asserted Claims: At least Claim 1 (Compl. ¶95).
  • Accused Features: The complaint alleges that the optics (lenses) disposed over the LEDs in the Accused Products have the claimed recessed top and bottom surfaces (Compl. ¶99).

U.S. Patent No. 8,052,307 - "Lens And Light Emitting Apparatus Having The Same," Issued November 8, 2011

  • Technology Synopsis: This patent describes a light-emitting apparatus with a specific package structure. The package on the substrate includes the light-emitting device, a surrounding phosphor layer, and a sealing resin layer, all of which are covered by a lens with recesses on its top and bottom surfaces (Compl. ¶¶34, 109).
  • Asserted Claims: At least Claim 1 (Compl. ¶109).
  • Accused Features: The complaint alleges the LED packages in the Accused Products contain a phosphor layer, a sealing resin layer, and an overlying lens with the claimed geometry (Compl. ¶¶112-113).

U.S. Patent No. 8,616,729 - "Lens And Light Emitting Apparatus Having The Same," Issued December 31, 2013

  • Technology Synopsis: This patent claims a lens with a specific geometry defined by dimensional ratios. It requires a lens body with a convex top surface having a central recessed part and a flat bottom surface with a central recessed part, where the ratio of the first recessed part's depth to the lens body's thickness is between 0.06 and 0.1 (Compl. ¶¶34, 123).
  • Asserted Claims: At least Claim 1 (Compl. ¶123).
  • Accused Features: The complaint alleges on information and belief that the lenses in the Accused Products meet the claimed geometric and ratio limitations (Compl. ¶¶124, 126).

U.S. Patent No. 8,213,093 - "Lens And Light Emitting Apparatus Having The Same," Issued July 3, 2012

  • Technology Synopsis: This patent claims a lens defined by a series of six distinct dimensional ratios relating the depths and widths of its top and bottom recessed parts to the overall lens body dimensions (Compl. ¶¶31, 136).
  • Asserted Claims: At least Claim 1 (Compl. ¶136).
  • Accused Features: The complaint alleges on information and belief that the lenses in the Accused Products meet the complex set of claimed ratio limitations (Compl. ¶¶139-140).

U.S. Patent No. 9,534,744 - "Light Emitting Apparatus," Issued January 3, 2017

  • Technology Synopsis: This patent describes a lens with a convex top surface that includes a flat top surface at its circumference, where this flat surface is disposed lower than the lowest point of a central recessed part. The claims also recite specific ranges for the maximum widths of the lens body and its curved portion (Compl. ¶¶34, 150).
  • Asserted Claims: At least Claim 1 (Compl. ¶150).
  • Accused Features: The complaint alleges on information and belief that the lenses in the Accused Products meet the claimed geometric and dimensional range limitations (Compl. ¶¶151, 154).

U.S. Patent No. 8,823,048 - "Light Emitting Apparatus," Issued September 2, 2014

  • Technology Synopsis: The patent describes a lens with three distinct portions: a center, a surrounding peripheral portion, and a surrounding side portion. The geometry is further defined by top and bottom recesses, an inwardly-concave curvature of the top recess, and a continuous, rounded-top surface on the peripheral portion (Compl. ¶¶34, 164).
  • Asserted Claims: At least Claim 1 (Compl. ¶164).
  • Accused Features: The complaint alleges the lenses in the Accused Products contain the claimed center, peripheral, and side portions with the specified recessed and curved surface geometries (Compl. ¶¶168-174).

U.S. Patent No. 8,395,183 - "Light Emitting Apparatus," Issued March 12, 2013

  • Technology Synopsis: This patent describes a light-emitting apparatus with fluorescent and encapsulant resin layers surrounding the light-emitting device. The lens has a downwardly concave top recess and an upwardly concave bottom recess, with a specific thickness profile and a claimed ratio of the recess depths (Compl. ¶¶34, 184).
  • Asserted Claims: At least Claim 1 (Compl. ¶184).
  • Accused Features: The complaint alleges the Accused Products include a phosphor layer, an encapsulant resin layer, and a lens with the claimed geometry and dimensional ratios (Compl. ¶¶187-192).

U.S. Patent No. 9,638,378 - "Light Emitting Apparatus," Issued May 2, 2017

  • Technology Synopsis: This patent is similar to the ’744 Patent, claiming a lens with a flat top surface at its circumference that is lower than both the lowest point of the top recess and the highest point of the bottom recess. It also recites specific dimensional and ratio limitations (Compl. ¶¶34, 202).
  • Asserted Claims: At least Claim 1 (Compl. ¶202).
  • Accused Features: The complaint alleges on information and belief that the lenses in the Accused Products meet these specific geometric and dimensional requirements (Compl. ¶¶203-208).

U.S. Patent No. 10,030,823 - "Light Emitting Apparatus," Issued July 24, 2018

  • Technology Synopsis: This patent claims a lens with a lateral surface perpendicular to its bottom surface. It recites specific ranges for the maximum thickness of this lateral surface and ratios relating the depth and width of a recessed part to the overall lens body dimensions (Compl. ¶¶34, 218).
  • Asserted Claims: At least Claim 1 (Compl. ¶218).
  • Accused Features: The complaint alleges on information and belief that the lenses in the Accused Products meet the claimed perpendicularity and dimensional ratio limitations (Compl. ¶¶219-222).

U.S. Patent No. 8,480,778 - "Air Cleaner Arrangements; Components; And, Methods," Issued July 9, 2013

  • Technology Synopsis: The patent describes a light source comprising a light guide plate, an optical sheet, and a conversion sheet. The optical sheet includes a diffusion sheet and a prism sheet, and is disposed such that the conversion sheet converts the color of light passing through both (Compl. ¶¶32, 232).
  • Asserted Claims: At least Claim 1 (Compl. ¶232).
  • Accused Features: The complaint alleges the Accused Products’ backlight includes a light guide plate, optical sheet, and conversion sheet arranged in the claimed manner (Compl. ¶¶233-237).

U.S. Patent No. 8,267,537 - "Backlight Unit And Display Device Having The Same," Issued September 18, 2012

  • Technology Synopsis: The patent claims a backlight unit with a specific mechanical assembly. It includes an LED module, a supporting case with a "bending part" that guides and fixes an end portion of the module, and a separate "fixing part" that fixes the module to the case (Compl. ¶¶33, 247).
  • Asserted Claims: At least Claim 1 (Compl. ¶247).
  • Accused Features: The complaint alleges the metal chassis of the Accused Products acts as the case, with pliable plastic clips serving as the "bending part" and fastening holes serving as the "fixing part" (Compl. ¶¶250-252).

U.S. Patent No. 8,723,411 - "Photoluminescent Sheet," Issued May 13, 2014

  • Technology Synopsis: This patent describes a photoluminescent sheet comprising a resin layer with a phosphor. The resin layer is "interposed between" a first (top) and second (bottom) protective film of uniform thickness, where both films are made of the same transparent synthetic resin (Compl. ¶¶35, 262).
  • Asserted Claims: At least Claim 1 (Compl. ¶262).
  • Accused Features: The complaint alleges the "quantum dot television" accused products contain a QD enhancement film (resin layer with phosphor) between two barrier film layers (protective films) made of the same material, such as PET (Compl. ¶¶263-266).

U.S. Patent No. 8,237,352 - "Photoluminescent Sheet," Issued August 7, 2012

  • Technology Synopsis: This patent claims a photoluminescent sheet with a resin layer containing a phosphor, a curing agent, and an additive for dispersion. The sheet is protected by top and bottom films made of a transparent synthetic resin that is "not curable by light" (Compl. ¶¶35, 276).
  • Asserted Claims: At least Claim 1 (Compl. ¶276).
  • Accused Features: The complaint alleges the quantum dot layer in the accused products contains the claimed components and is protected by barrier films (e.g., PET) that are not light-curable (Compl. ¶¶277-281).

III. The Accused Instrumentality

  • Product Identification: The accused instrumentalities are Hisense televisions and displays, including all "LCD LED, LED, ULED, QLED, MINI-LED ULED, and MINI-LED QLED" models (Compl. ¶36). The complaint identifies specific product series such as U6, R6, H7, A6, U7, and QD6, and names specific models as exemplary infringing products, including the 50R6E3 and 50U6H televisions (Compl. ¶¶36, 47, 60).
  • Functionality and Market Context: The accused products are televisions that use an LED backlight unit to illuminate a display panel (Compl. ¶¶28-35). The infringement allegations focus on the internal construction of these backlight units, which are alleged to contain components such as LED strips, individual LEDs with lenses, connecting substrates, guide protrusions, reflection sheets, housings, and photoluminescent "quantum dot" sheets (Compl. ¶¶35-36, 49, 61). The complaint includes a teardown photograph showing multiple horizontal LED strips, referred to as "module substrate," containing LEDs and connecting terminals at both ends (Compl. p. 13). Defendants are alleged to be a major global television manufacturer with a stated goal of becoming the top seller in the U.S. market (Compl. ¶41).

IV. Analysis of Infringement Allegations

’415 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
at least one module substrate comprising connecting terminals at both side ends thereof The accused TVs contain multiple LED strips, each identified as a "module substrate," which have connecting terminals at both ends. ¶49 col. 2:41-44
a light emitting diode on the module substrate The LED strips in the accused TVs include multiple LEDs, identified as the claimed "light emitting diode." ¶49 col. 2:45-46
a plurality of connecting substrates connected to the connecting terminals of the module substrate The accused TVs use connecting substrates and terminals to connect the multiple LED strips to each other in series. ¶50 col. 2:47-50
wherein the connecting substrate comprises a termination connecting substrate, by which the connecting terminal provided at one end of a final module substrate of the module substrates is prepared as a closed loop circuit The complaint alleges that the series connection of multiple LED strips, each including a positive and negative line, comprises a closed loop circuit. ¶50 col. 3:37-46
  • Identified Points of Contention (’415 Patent):
    • Scope Questions: A primary point of contention may be the interpretation of "closed loop circuit." The defense may argue that this term, as taught in the patent with a specific "termination connecting substrate" (FIG. 8), requires a feedback loop or a specific return path distinct from a standard series electrical circuit. The question for the court will be whether the allegation that the LED strips are "connected in series" (Compl. ¶50) is sufficient to meet the "closed loop circuit" limitation.
    • Technical Questions: What evidence does the complaint provide that the connectors between the LED strips in the accused products function as the claimed "termination connecting substrate" to form the claimed loop, as opposed to simply passing current in series?

’380 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
a light guide member outputting surface light upward Each LED in the backlight module has a transparent glass cover over the top, which the complaint alleges is a "light guide member" that guides light upward. ¶61 col. 2:35-40
a board disposed to a first side of the light guide member The accused products include an LED strip, identified as a "board," to which the transparent glass cover ("light guide member") is connected or disposed. ¶62 col. 2:53-54
a plurality of light-emitting devices mounted on a first side of the board Multiple LEDs are mounted on the front side of the LED strip. A teardown image shows these LEDs on the strip (Compl. p. 25). ¶63 col. 2:55-57
a reflection sheet under the light guide member A reflection sheet is placed under the light guide members, with the light-emitting portions protruding above the sheet. ¶64 col. 2:20-24
a housing receiving the light guide member, the light-emitting devices, the board, and the reflection sheet The exterior housing and frame of the TV supports the internal components, including the metal plate, LED strip, LEDs, and reflection sheet. ¶66 col. 2:8-14
a metal plate attached to a second side of the board and a first side of the housing A metal plate provides support for the backlight module and is located on the second (back) side of the LED strip board and on the first (interior) side of the housing. ¶67 col. 2:65-67
wherein the board is a flexible PCB that includes a first portion disposed between the metal plate and the first side of the light guide member, and a second portion disposed between the reflection sheet and the housing... The LED strip board is alleged to be a flexible PCB. The complaint maps the "first portion" to the part of the board with an LED and guide member, and the "second portion" to the remaining part of the board. ¶70 col. 4:59-67
  • Identified Points of Contention (’380 Patent):
    • Scope Questions: A central dispute may arise over the term "light guide member." The patent specification frequently refers to this component as a "light guide panel (LGP)" (e.g., '380 Patent, col. 2:35), which typically implies a large, single sheet used in edge-lit displays. The complaint alleges this term reads on the individual optical lenses over each LED in a direct-lit system (Compl. ¶61). This raises the question of whether the claim term can be construed to cover technology that is structurally and functionally different from the primary embodiment disclosed.
    • Technical Questions: Does the complaint provide sufficient evidence that the accused LED strip is a "flexible PCB" with two functionally and spatially distinct portions as claimed? The attempt to map this limitation by dividing the strip into the "part...with an LED" and the "remaining part" (Compl. ¶70) may be challenged as an artificial distinction not reflective of the component's actual structure or the patent's teaching.

V. Key Claim Terms for Construction

  • For the ’415 Patent:

    • The Term: "closed loop circuit"
    • Context and Importance: This term is the central feature of the asserted independent claim. Whether the accused products' series-wired LED strips constitute a "closed loop circuit" as prepared by a "termination connecting substrate" will be determinative of infringement for this patent. Practitioners may focus on this term because the complaint's allegations appear to equate a standard series circuit with the more specific "closed loop" language of the claim.
    • Intrinsic Evidence for Interpretation:
      • Evidence for a Broader Interpretation: The patent states that the apparatus allows "the end portion of the LED bar to form a closed loop" and that the termination substrate is "mounted on the end portion of a third module substrate" (’415 Patent, col. 3:41-44). This could be argued to generally describe the completion of an electrical circuit at the end of a series of modules.
      • Evidence for a Narrower Interpretation: The patent’s Figure 8 depicts a specific "termination connecting substrate" (145) with dedicated circuit patterns (146C, 147C, 148C) that connect corresponding pads (e.g., R1 to R2) to form the loop (’415 Patent, col. 3:37-46). An argument could be made that the claim requires this specific structure or a clear equivalent, not just a simple wire or connector completing a series circuit.

  • For the ’380 Patent:

    • The Term: "light guide member"
    • Context and Importance: The accused products are direct-lit televisions using individual lenses over each LED, whereas the patent specification appears to describe an edge-lit system using a large panel to distribute light. The construction of this term is critical to determining if the patent applies to the accused technology.
    • Intrinsic Evidence for Interpretation:
      • Evidence for a Broader Interpretation: The claim language itself is broad, requiring only "a light guide member outputting surface light upward" (’380 Patent, cl. 1). Plaintiff may argue that an individual lens over an LED performs this exact function and is therefore a "member" that "guides light."
      • Evidence for a Narrower Interpretation: The detailed description repeatedly and consistently refers to the component as a "light guide panel (LGP)" (’380 Patent, col. 2:35, 2:40, etc.). Figure 1 (item 120) clearly depicts a large, single panel. A defendant may argue that the term "light guide member" should be limited by this consistent disclosure to an LGP-type structure, not individual lenses.

VI. Other Allegations

  • Indirect Infringement: The complaint alleges both induced and contributory infringement for all asserted patents. Inducement is based on allegations that Defendants manufacture, sell, and distribute the Accused Products with instructions, manuals, and marketing materials that direct end-users to use them in an infringing manner (Compl. ¶¶51, 72). Contributory infringement is based on allegations that the accused components are material to the inventions, are not staple articles of commerce, and are known by Defendants to be especially adapted for infringing use (Compl. ¶¶52, 73).
  • Willful Infringement: The complaint alleges willful infringement based on Defendants' alleged knowledge of the patents. This knowledge is predicated on the assertion that the patents were "widely publicized during and after LG Innotek’s sale to Suzhou Lekin Semiconductor" (Compl. ¶¶53, 74, etc.). This allegation implies pre-suit knowledge of the patents-in-suit.

VII. Analyst’s Conclusion: Key Questions for the Case

  • A core issue will be one of definitional scope: can claim terms rooted in specific patent embodiments, such as "light guide member" (disclosed as a large panel) and "closed loop circuit" (disclosed with a specific termination substrate), be construed broadly enough to cover the different technologies of individual LED lenses and standard series-wired LED strips present in the accused direct-lit televisions?
  • A key evidentiary question will be one of structural mapping: particularly for the numerous patents claiming lenses with specific geometric ratios and profiles, can the plaintiff provide sufficient technical evidence to prove that the mass-produced lenses in the accused products meet every one of the precise dimensional limitations required by the asserted claims?
  • A central issue for damages will be willfulness: can the plaintiff establish that general publicity surrounding a corporate asset sale involving a large patent portfolio is sufficient to prove that the defendants knew of, or were willfully blind to, the specific sixteen patents asserted in this case, thereby supporting a claim of pre-suit willful infringement?