DCT

2:25-cv-00440

Longitude Licensing Ltd v. BOE Technology Group Co Ltd

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 2:25-cv-00440, E.D. Tex., 04/25/2025
  • Venue Allegations: Venue is asserted under 28 U.S.C. § 1391(c)(3), which permits suing a foreign defendant not resident in the United States in any judicial district.
  • Core Dispute: Plaintiffs allege that LCD panels manufactured by Defendant BOE, and consumer electronics such as monitors and TVs sold by Defendant LG that incorporate those panels, infringe three patents related to the physical layout of signal terminals and inspection features in LCDs.
  • Technical Context: The patents address foundational technologies for improving signal integrity, reliability, and manufacturability in the liquid crystal display (LCD) panels that are ubiquitous in consumer and commercial electronics.
  • Key Procedural History: The complaint alleges that Plaintiffs and Defendant BOE engaged in licensing negotiations from approximately January 2020 to January 2024. During these negotiations, Plaintiffs allegedly provided BOE with actual notice of infringement for the '146 and '512 patents, including the provision of claim charts. Allegations of willful infringement are predicated on these pre-suit communications.

Case Timeline

Date Event
2003-08-08 U.S. Patent No. 7,636,146 Priority Date
2009-03-23 U.S. Patent No. 8,319,512 Priority Date
2009-12-03 U.S. Patent No. 8,391,020 Priority Date
2009-12-22 U.S. Patent No. 7,636,146 Issues
2012-11-27 U.S. Patent No. 8,319,512 Issues
2013-03-05 U.S. Patent No. 8,391,020 Issues
2020-01-02 Plaintiff allegedly provides BOE with notice of '146 patent
2021-04-08 Plaintiff allegedly provides BOE with notice of '512 patent
2022-09-15 Plaintiff allegedly provides LG with notice of '512 patent
2023-09-27 Plaintiff allegedly provides LG with notice of '146 patent
2025-04-25 Complaint Filed

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

U.S. Patent No. 7,636,146 - "Electro-Optical Panel, System with Terminals Having Different Corresponding Characteristics"

The Invention Explained

  • Problem Addressed: The patent describes a conflict in designing input terminals for electro-optical panels. Making terminals small saves space but increases electrical resistance, which can degrade high-frequency signals ("dulling the waveform"). Making all terminals large to reduce resistance consumes too much space, especially on panels with many inputs ('146 Patent, col. 2:5-14).
  • The Patented Solution: The invention proposes tailoring the size of input terminals to the characteristics of the signal they carry. Terminals supplied with high-frequency "driving signals" (e.g., clock signals) are designed with a larger area to minimize resistance and preserve signal integrity. Terminals for lower-frequency "image signals" can be made smaller to conserve space, as their waveforms are less susceptible to degradation from resistance ('146 Patent, Abstract; col. 2:46-54).
  • Technical Importance: This design approach allows for a more compact and reliable panel interface by balancing the competing needs for high-fidelity signal transmission and miniaturization ('146 Patent, col. 2:16-19).

Key Claims at a Glance

  • The complaint asserts independent claim 23 (Compl. ¶73).
  • The essential elements of claim 23 are:
    • An electro-optical panel comprising a substrate with data lines, scanning lines, and pixels.
    • A clock signal input terminal and an image signal input terminal implemented on the substrate.
    • A scanning line drive circuit.
    • A mounting member (e.g., a flexible cable) distinct from but connected to the substrate.
    • The mounting member has a first wiring connected to the clock signal input terminal and a second wiring connected to the image signal input terminal.
    • A key limitation requires that the clock signal input terminal overlaps the first wiring by a larger area than the area at which the image signal input terminal overlaps the second wiring.
  • The complaint reserves the right to assert additional claims (Compl. ¶74).

U.S. Patent No. 8,319,512 - "Flexible Substrate Including Inspection Electrode for Outputting Signal Processed in Integrated Circuit, Electro-Optical Device, and Electronic Device"

The Invention Explained

  • Problem Addressed: The patent notes the difficulty of testing signals that are used for internal processing within an integrated circuit (IC) mounted on a flexible substrate. Adding external test points for these signals on the main device panel increases complexity and the number of connections required ('512 Patent, col. 1:26-39).
  • The Patented Solution: The invention places an "inspection electrode" directly on the flexible substrate itself, electrically connected to the IC. This electrode is designed to output signals processed within the IC, including internal signals not otherwise accessible, allowing a test probe to monitor them directly on the substrate. The patent also describes a switching section to turn the inspection functionality on or off ('512 Patent, Abstract; col. 2:55-62).
  • Technical Importance: This innovation facilitates manufacturing quality control by enabling direct, real-time assessment of internal circuit performance without complicating the primary panel interface, thereby improving reliability and reducing defects ('512 Patent, col. 2:39-40).

Key Claims at a Glance

  • The complaint asserts independent claim 1 (Compl. ¶106).
  • The essential elements of claim 1 are:
    • A flexible substrate comprising a substrate body, lines, and connection terminals.
    • An integrated circuit (IC) arranged on the substrate body.
    • An inspection electrode arranged on the substrate body, connected to the IC, and capable of outputting a signal processed in the IC.
    • A switching section that switches the operation of the inspection electrode on or off, causing it to either output or not output the processed signal.
  • The complaint reserves the right to assert additional claims (Compl. ¶107).

U.S. Patent No. 8,391,020 - "Electro-Optical Device, Electro-Optical Panel, and Electronic Apparatus"

The Invention Explained

  • Technology Synopsis: The patent addresses the need to reliably verify electrical connections between an electro-optical panel and associated circuit substrates (e.g., FPCs) (Compl. ¶23). It discloses specific terminal grouping and wiring configurations, where terminals at opposite ends of a group or in adjacent groups are connected by dedicated wiring paths, including paths that extend around the display area. This allows for an end-to-end electrical check to confirm the integrity of the bonded connections ('020 Patent, col. 2:6-18).

Key Claims at a Glance

  • Asserted Claims: The complaint asserts independent claim 1 (Compl. ¶136).
  • Accused Features: The complaint alleges that the accused BOE panels and LG devices contain electro-optical panels and circuit substrates with terminal portions and connection wirings arranged in a manner that practices the claimed invention (Compl. ¶¶142-159). For example, it alleges a "first terminal" and a "fourth terminal" are electrically connected through a "first connection wiring" on the electro-optical panel (Compl. ¶150).

III. The Accused Instrumentality

Product Identification

The complaint identifies two classes of accused products: "BOE Accused Instrumentalities," which are LCD panels and modules manufactured by BOE, and "LG Accused Instrumentalities," which are downstream products such as monitors and TVs manufactured by LG that incorporate the accused BOE components (Compl. ¶¶39, 43). The primary exemplary product is the LG 27" 4K UHD IPS display (model number 27SR73U), which is alleged to contain a BOE LCD panel (part number MV270QUM-N50) (Compl. ¶74).

Functionality and Market Context

The complaint alleges the accused BOE panels are foundational components for a wide range of display applications, including smartphones, monitors, and TVs (Compl. ¶40). The complaint uses extensive photographic evidence, including magnified images of the panel's internal structures, to identify the specific array substrates, flexible printed circuits (FPCs), integrated circuits, signal terminals, and wiring that allegedly practice the patented inventions (Compl. ¶¶77-91, 110-120, 140-159). BOE is positioned as a "world leader in the global semiconductor display industry," while LG is identified as having the second-largest global TV market share by revenue as of May 2024 (Compl. ¶¶28, 37). The complaint references an image showing a "BOE" logo on a printed circuit board inside the LG monitor to link the two defendants' products (Compl. ¶76; p. 21).

IV. Analysis of Infringement Allegations

'146 Patent Infringement Allegations

Claim Element (from Independent Claim 23) Alleged Infringing Functionality Complaint Citation Patent Citation
a substrate; data lines; scanning lines...; pixels... The BOE LCD panel comprises an array substrate with vertically-oriented data lines, horizontally-oriented scanning lines, and pixels at their intersections (Compl. ¶77; pp. 22-25). ¶¶77-80 col. 12:43-50
a clock signal input terminal supplied with a clock signal; an image signal input terminal supplied with an image signal The array substrate is alleged to have distinct input terminals for a clock signal and an image signal (Compl. ¶¶81, 83). ¶¶81, 83 col. 16:1-3
a mounting member that is distinct from and connected to the substrate A flexible printed circuit (FPC) is identified as a distinct mounting member connected to the array substrate (Compl. ¶¶87-88). ¶87 col. 16:10-12
the mounting member comprising: a first wiring that is connected to the clock signal input terminal; and a second wiring that is connected to the image signal input terminal The FPC is alleged to comprise separate wirings connected to the clock signal input terminal and the image signal input terminal, respectively (Compl. ¶¶89-90). ¶¶89-90 col. 16:13-18
wherein the clock signal input terminal overlaps the first wiring of the mounting member by a larger area than an area at which at least one of the image signal input terminals overlaps the second wiring... The complaint provides a magnified image alleging that the overlap area for the clock signal terminal and its wiring is approximately four times larger ("4x") than the overlap area for the image signal terminal and its wiring ("1x") (Compl. ¶91; p. 35). ¶91 col. 16:19-24

Identified Points of Contention

  • Technical Questions: A primary factual question will be verifying the complaint's technical assertions. Does the terminal designated as the "clock signal input terminal" actually receive a higher-frequency signal than the one designated as the "image signal input terminal" in the accused product's operation? The complaint's visual evidence of a "4x" vs "1x" size difference is probative but depends on the functional nature of the signals being correctly identified according to the patent's teachings.
  • Scope Questions: The patent distinguishes between "driving signals" and "image signals," with the former having a "higher frequency component" ('146 Patent, col. 2:31-34). The case may turn on whether the signals supplied to the accused terminals in the BOE panel fit these technical definitions as they would be construed by a person of ordinary skill in the art.

'512 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
A flexible substrate comprising: a substrate body; a plurality of lines...; a plurality of connection terminals... The accused FPC is alleged to be a flexible substrate with a body, conductive lines, and connection terminals (Compl. ¶110; pp. 41-43). ¶¶110-112 col. 9:44-50
an integrated circuit that is arranged on the substrate body... An IC is shown arranged on the flexible substrate body (Compl. ¶113; p. 44). ¶113 col. 9:51-53
an inspection electrode that is arranged on the substrate body and electrically connected to the integrated circuit and capable of outputting a signal processed in the integrated circuit The complaint identifies four "inspection electrodes" on the substrate, showing electrical connections to the IC. It alleges these electrodes are capable of outputting signals processed within the IC, such as from internal high and low side buffers (Compl. ¶114; pp. 45, 49). ¶¶114-117 col. 9:54-58
a switching section that switches an operation of the inspection electrode on/off to cause the inspection electrode to output or not to output the signal processed in the integrated circuit The complaint alleges that an "Output Switch Block" within the IC functions as the claimed switching section. It provides a circuit diagram illustrating how this block can select a processed signal to output to the inspection electrode or switch all buffer signals off (Compl. ¶119; pp. 50-51). ¶¶119-120 col. 9:59-62

Identified Points of Contention

  • Scope Questions: A key question for claim construction and infringement will be the scope of "inspection electrode". Does the term cover any test point on a flexible substrate, or is it limited, as the patent's background suggests, to an electrode that provides access to signals not otherwise available externally (e.g., purely internal processing signals)? The defendant may argue the accused electrodes are conventional test pads for signals that are ultimately output, not true "inspection" electrodes in the patent's novel sense.
  • Technical Questions: The complaint alleges the "Output Switch Block" can turn the output "on/off." An evidentiary dispute may arise over whether this circuit's actual operation meets the claim limitation of switching "an operation of the inspection electrode," or if it merely switches the signal input to the electrode, a subtle but potentially meaningful distinction in function.

V. Key Claim Terms for Construction

  • Term: "clock signal input terminal" ('146 Patent, Claim 23)

  • Context and Importance: The entire inventive concept of claim 23 hinges on this terminal having a "larger area" of overlap with its wiring than the "image signal input terminal". The definitions of "clock signal" and "image signal" are therefore critical, as they dictate which physical terminals on the accused device must be compared to assess infringement. Practitioners may focus on this term because the structural "larger area" limitation is meaningless without a proper functional mapping of the signals.

  • Intrinsic Evidence for Interpretation:

    • Evidence for a Broader Interpretation: The specification broadly categorizes inputs as "driving signals" and "image signals," stating that driving signals have a "higher frequency component" ('146 Patent, col. 2:31-34). This could support an interpretation where any relatively high-frequency timing or control signal qualifies as a "clock signal."
    • Evidence for a Narrower Interpretation: The embodiments consistently refer to the "Y clock signal YCK" and "inverted Y clock signal YCKB" as examples of driving signals for the scanning-line drive circuit ('146 Patent, col. 7:35-39). A defendant may argue the term should be narrowed to these specific types of system clock signals, rather than any periodic control signal.

  • Term: "inspection electrode" ('512 Patent, Claim 1)

  • Context and Importance: This term defines the core of the '512 invention. The patent's contribution is placing this element on the flexible substrate to monitor internal IC signals. Its construction will determine whether the accused test pads perform the same novel function or are merely conventional features.

  • Intrinsic Evidence for Interpretation:

    • Evidence for a Broader Interpretation: The claim requires the electrode be "capable of outputting a signal processed in the integrated circuit," without limiting what kind of processed signal. The specification notes the electrode can output "signals that are to be output from the flexible substrate" as well as internal signals ('512 Patent, col. 2:6-12), which could support a broader definition.
    • Evidence for a Narrower Interpretation: The patent’s summary emphasizes the ability to monitor a signal "that is not output from the flexible substrate, or a signal used only for the internal processing of the integrated circuit" ('512 Patent, col. 2:32-37). A defendant could argue that to be an "inspection electrode" in the patent's context, it must be for monitoring such non-output signals, distinguishing it from a standard test point for a signal already destined for an external connection.

VI. Other Allegations

Indirect Infringement

  • Inducement: The complaint alleges BOE induced infringement by selling the accused LCD panels to customers, including LG, with the specific intent that they would be incorporated into infringing end-products sold in the U.S. (Compl. ¶¶59-60). It alleges LG induced infringement by its customers by selling and providing instructions for the final infringing products (Compl. ¶¶66, 68).
  • Contributory Infringement: The complaint alleges BOE contributed to infringement by selling the LCD panels, which are alleged to be a material part of the patented inventions and not a staple article of commerce with substantial non-infringing uses (Compl. ¶63).

Willful Infringement

  • Willfulness is alleged against both defendants.
    • Against BOE, the claim is based on alleged actual notice and pre-suit knowledge gained during licensing negotiations beginning as early as January 2, 2020, for the '146 patent and April 8, 2021, for the '512 patent (Compl. ¶53).
    • Against LG, the claim is based on alleged actual notice provided on September 15, 2022, for the '512 patent and September 27, 2023, for the '146 patent (Compl. ¶58). For the '020 patent, willfulness allegations against both defendants are based on knowledge from the filing of the complaint itself (Compl. ¶¶51, 57, 166-167).

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

  • A core issue will be one of technical mapping: Can Plaintiffs prove that the physical structures in the accused BOE panels—specifically the different-sized terminals and the test electrodes—perform the precise technical functions required by the claims? This will require not just showing structural similarities, as the complaint's visuals do, but also providing evidence of the operational characteristics of the signals and circuits during use.
  • A second central issue will be one of claim scope and non-obviousness: The patents claim specific solutions to known problems in display manufacturing (signal integrity, testability). The defendants will likely challenge the validity of the claims by arguing that the claimed solutions are obvious variations of known design techniques. The case will thus turn on whether the specific claimed configurations, such as the "larger area" rule of the '146 patent or the switchable on-substrate "inspection electrode" of the '512 patent, represent a non-obvious inventive step over the prior art.
  • Finally, a key question will concern the chain of liability: The case targets both the upstream component manufacturer (BOE) and the downstream product integrator (LG). A significant focus of discovery and trial will be on proving the knowledge and intent elements for indirect infringement, particularly BOE's alleged intent to induce LG's infringement, and how damages should be apportioned between the maker of the infringing component and the seller of the final infringing device.