DCT

2:24-cv-00086

Bishop Display Tech LLC v. Heesung Electronics Ltd

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Key Events
Complaint

I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 2:24-cv-00086, E.D. Tex., 02/08/2024
  • Venue Allegations: Plaintiff alleges venue is proper because Defendant is a foreign entity that may be sued in any judicial district. Further, Plaintiff alleges Defendant committed acts of patent infringement in Texas by placing accused products into the stream of commerce with the knowledge they would be sold and used in the district.
  • Core Dispute: Plaintiff alleges that Defendant’s thin-film transistor liquid crystal displays (TFT-LCDs) and liquid crystal modules (LCMs) infringe six U.S. patents related to the structure, manufacture, and operation of liquid crystal displays.
  • Technical Context: The dispute centers on foundational technologies for modern flat-panel displays, specifically concerning the arrangement of electrodes and other components within individual pixels to improve image quality, viewing angles, and manufacturing reliability.
  • Key Procedural History: The complaint alleges that Defendant’s customers and business partners, LGE, LGEUS, and LGD, received notice of infringement of the asserted patents from a former patent owner as early as February 8, 2017, and again on July 29, 2020. Plaintiff alleges that Defendant, through its business and contractual relationships with these entities, received actual or constructive notice of the patents, a fact which may be material to allegations of indirect and willful infringement.

Case Timeline

Date Event
1999-10-05 ’293 Patent Priority Date
1999-10-21 ’798 Patent Priority Date
2000-04-05 ’829 Patent Priority Date
2000-07-24 ’208 Patent Priority Date
2000-08-30 ’769 Patent Priority Date
2001-09-27 ’303 Patent Priority Date
2003-02-25 ’798 Patent Issue Date
2004-09-07 ’829 Patent Issue Date
2004-10-05 ’293 Patent Issue Date
2004-11-09 ’208 Patent Issue Date
2005-02-01 ’303 Patent Issue Date
2005-06-14 ’769 Patent Issue Date
2017-02-08 LGD allegedly received notice of infringement of certain patents from former owner
2017-03-07 LGD allegedly replied to notice letter
2020-07-29 LGE and LGD allegedly received notice of infringement of certain patents
2024-02-08 Complaint Filing Date

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

U.S. Patent No. 6,525,798 - "Liquid Crystal Display Unit," issued Feb. 25, 2003

The Invention Explained

  • Problem Addressed: The patent’s background section describes technical challenges in early In-Plane Switching (IPS) type liquid crystal displays, including a phenomenon called "coloring," where the perceived color tone shifts depending on the viewing angle, as well as low light-use efficiency (’798 Patent, col. 1:47-53, col. 2:1-2).
  • The Patented Solution: The invention proposes using multiple "electrode pairs" within a single pixel, where at least one pair has a different geometrical shape—specifically, a different electrode thickness—from the others. This variation in geometry creates different electric field distributions, which in turn produce different wavelength dispersion characteristics that can be engineered to cancel each other out, thereby reducing color shifting and improving luminance for specific colors (’798 Patent, Abstract; col. 3:6-16).
  • Technical Importance: This approach provided a method for tuning pixel-level optical properties to improve color fidelity and viewing angle performance, which were critical for the adoption of IPS technology in high-quality displays.

Key Claims at a Glance

  • The complaint asserts independent claim 1 (Compl. ¶34).
  • Essential elements of claim 1 include:
    • A liquid crystal display unit comprising a plurality of pixels, scanning signal lines, and video signal lines.
    • An array substrate, a counter substrate, and a liquid crystal layer sandwiched between them.
    • Each pixel includes a plurality of common electrodes and pixel electrodes.
    • Each pixel includes a plurality of electrode pairs, each pair comprising one common electrode and an adjacent pixel electrode.
    • Crucially, "at least one of the electrode pairs differs from other electrode pairs in a thickness of its common electrode or a thickness of its pixel electrode."
  • The complaint does not explicitly reserve the right to assert dependent claims.

U.S. Patent No. 6,787,829 - "Liquid Crystal Display Panel," issued Sep. 7, 2004

The Invention Explained

  • Problem Addressed: The patent describes image quality degradation caused by the parasitic electric field between an image signal line and an adjacent common electrode. This field creates an "uncontrollable region" of liquid crystal molecules, which can cause light leakage and reduce the display's effective aperture ratio, or brightness (’829 Patent, col. 1:52–col. 2:10).
  • The Patented Solution: The invention specifies a particular material selection for the electrodes within a pixel. The electrode located adjacent and parallel to a signal line (e.g., an image or scanning signal line) is made of an "opaque conductor" to act as a light shield for the uncontrollable region. To compensate for the loss of aperture, at least one of the other electrodes in the pixel is made of a "transparent conductor," allowing light to pass through the main display area (’829 Patent, Abstract; col. 3:5-13).
  • Technical Importance: This design offers a structural solution to balance the competing needs of shielding stray electric fields and maximizing light throughput, thereby improving both contrast and brightness.

Key Claims at a Glance

  • The complaint asserts independent claim 1 (Compl. ¶50).
  • Essential elements of claim 1 include:
    • A liquid crystal display panel with an array substrate, counter substrate, and liquid crystal layer.
    • Image signal lines and perpendicular scanning signal lines located on the array substrate.
    • A line-shaped pixel electrode and a common electrode located in each pixel region.
    • A switching element connecting the pixel electrode to a signal line.
    • Critically, of the pixel and common electrodes, "the electrode that is located adjacent to and parallel to one of the image signal lines or one of the scanning signal lines comprises an opaque conductor, and at least one of the other electrodes comprises a transparent conductor."
  • The complaint does not explicitly reserve the right to assert dependent claims.

Multi-Patent Capsule: U.S. Patent No. 6,801,293 - "Method for Manufacturing an In-Plane Electric Field Mode Liquid Crystal Element," issued Oct. 5, 2004

  • Technology Synopsis: This patent addresses a manufacturing problem known as "black dot nonuniformities" in IPS displays, which it attributes to ions concentrating at electrode edges. The claimed solution is a manufacturing method that includes a "stripping step of stripping, by rubbing, a predetermined portion of the orientation film on the electrodes or lines" to remove the source of these defects (’293 Patent, Abstract; col. 51:52-62).
  • Asserted Claims: Claim 1 is asserted (Compl. ¶68).
  • Accused Features: The complaint alleges that the accused TFT-LCD products are manufactured by a process that includes the claimed rubbing and stripping steps on the orientation film, as evidenced by a UV light examination showing a glow from the film (Compl. ¶¶70-71).

Multi-Patent Capsule: U.S. Patent No. 6,816,208 - "Liquid Crystal Display Device," issued Nov. 9, 2004

  • Technology Synopsis: This patent aims to correct display unevenness caused by signal degradation along the length of scanning lines. It discloses a device structure where the storage capacity of a pixel on the signal "feeding side" is intentionally made larger than that of an adjacent pixel on the "termination side." This difference in capacitance is achieved by "varying an aperture in the common electrode" of the adjacent pixel relative to the first (’208 Patent, Abstract).
  • Asserted Claims: Claim 1 is asserted (Compl. ¶85).
  • Accused Features: The accused products are alleged to have capacitive accumulation portions whose storage capacity is varied between adjacent pixels by implementing different apertures in the common electrodes, as shown in a micrograph provided in the complaint (Compl. ¶¶86-87).

Multi-Patent Capsule: U.S. Patent No. 6,850,303 - "Liquid Crystal Display Device Having Additional Storage Capacitance," issued Feb. 1, 2005

  • Technology Synopsis: The patent seeks to improve the aperture ratio of IPS displays while maintaining sufficient storage capacitance. The invention describes a layered capacitor structure where the "common wiring and the storage capacity electrode are layered so as to hold at least some part of the pixel electrode in between through insulating layers." This three-dimensional arrangement allows for a larger capacitor in a smaller footprint (’303 Patent, Abstract).
  • Asserted Claims: Claim 1 is asserted (Compl. ¶100).
  • Accused Features: The accused products are alleged to embody this layered structure, where a portion of the common wiring is sandwiched between the pixel electrode and a storage capacity electrode, separated by an insulating layer (Compl. ¶¶106-107).

Multi-Patent Capsule: U.S. Patent No. 6,906,769 - "Liquid Crystal Screen Display," issued Jun. 14, 2005

  • Technology Synopsis: This patent addresses display unevenness caused by localized ion generation, particularly after laser repairs expose signal lines. The patented solution involves intentionally creating regions where a "first conductive member," such as a gate signal line, is "in partial contact with the alignment layer" and to which a negative voltage is applied. This structure is intended to uniformly generate and distribute ions across the liquid crystal layer, preventing localized concentrations that cause display defects (’769 Patent, Abstract).
  • Asserted Claims: Claim 1 is asserted (Compl. ¶120).
  • Accused Features: The accused products are alleged to include gate signal lines formed on a substrate and interposed between the substrate and its alignment layer, such that they are in partial contact with the alignment layer and receive a negative voltage during operation (Compl. ¶124).

III. The Accused Instrumentality

Product Identification

  • The accused products are Heesung-manufactured liquid crystal modules (LCMs), thin-film transistor liquid crystal displays (TFT-LCDs), and products containing them (Compl. ¶3). The complaint identifies as an exemplar the Heesung LCM model no. HC49EQH-SLXA1-211X, which is a component of the LG TV model no. 49SM8600PUA (Compl. ¶34).

Functionality and Market Context

  • The accused products are core components used in a wide range of electronic devices with flat-panel screens, such as televisions, monitors, and laptops (Compl. ¶¶3, 14). The complaint alleges that Heesung researches, designs, develops, and manufactures these components, which are then imported and sold in the U.S. through distributors and integrated into end-user products (Compl. ¶22). The complaint alleges that Heesung is an "LG Partner" and supplies these components to customers like LGE for incorporation into final products sold by retailers such as Best Buy (Compl. ¶26). The complaint provides a photograph of a label on the exemplar LCM identifying "HEESUNG ELECTRONICS CO., LTD" as the manufacturer (Compl. ¶34).

IV. Analysis of Infringement Allegations

’798 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
a liquid crystal display unit comprising: a plurality of pixels each including a plurality of common electrodes, a plurality of pixel electrodes, and a semiconductor switching element... The accused Heesung LCMs contain pixels with common electrodes, pixel electrodes, and semiconductor switching elements. A micrograph shows these components labeled on an array substrate. ¶35; p. 11 fig. col. 6:25-30
an array substrate having the pixels...a counter substrate arranged opposite the array substrate, and a liquid crystal layer sandwiched between the array substrate and the counter substrate... The accused LCMs comprise an array substrate, a counter substrate, and a liquid crystal layer between them. ¶36; p. 12 fig. col. 6:31-37
wherein each of the pixels includes a plurality of electrode pairs, each electrode pair comprising one of the common electrodes and an adjacent one of the pixel electrodes... Each pixel in the accused LCMs includes multiple electrode pairs, each formed by a common electrode and an adjacent pixel electrode. A micrograph identifies an "Electrode pair comprising common and adjacent pixel electrode." ¶37; p. 12 fig. col. 6:46-50
and at least one of the electrode pairs differs from other electrode pairs in a thickness of its common electrode or a thickness of its pixel electrode. In the accused LCMs, at least one electrode pair allegedly has a common electrode with a different thickness than other pairs. A micrograph includes a callout stating, "Thickness of the common electrode in at least one of the electrode pairs differs." ¶37; p. 12 fig. col. 6:50-57
  • Identified Points of Contention:
    • Evidentiary Question: What is the basis for the assertion in the complaint's visual evidence (Compl. ¶37) that the thickness of the common electrode differs between electrode pairs? The infringement analysis may depend on expert testimony and measurements to substantiate this visual claim.
    • Scope Question: Does any minute, unintentional variation in manufacturing satisfy the "differs...in a thickness" limitation, or does the claim require a functionally significant and intentional difference, as suggested by the patent's specification which links thickness variation to controlling wavelength dispersion (’798 Patent, col. 4:42-51)?

’829 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
a liquid crystal display panel comprising: an array substrate, a counter substrate opposing the array substrate, and a liquid crystal layer sandwiched between a surface of the array substrate and a surface of the counter substrate... The accused TFT-LCDs are liquid crystal display panels containing an array substrate, counter substrate, and a liquid crystal layer. ¶51; p. 18 fig. col. 12:4-9
a plurality of image signal lines located over the surface of the array substrate...the image signal lines being aligned in a same direction; a plurality of scanning signal lines...being located perpendicular to the image signal lines; The accused products have image signal lines and perpendicular scanning signal lines on the array substrate. A micrograph labels these perpendicular lines. ¶52; p. 19 fig. col. 12:10-17
a line-shaped pixel electrode located in each of pixel regions...a common electrode located in each of the pixel regions and located parallel to the pixel electrode; The accused products allegedly contain line-shaped pixel electrodes and parallel common electrodes within each pixel region. A micrograph shows these labeled components. ¶53; p. 19 fig. col. 12:18-27
wherein...the electrode that is located adjacent to and parallel to one of the image signal lines or one of the scanning signal lines comprises an opaque conductor... The common electrode, which is adjacent to an image signal line, is alleged to be an opaque conductor. A micrograph labels the "Common electrode comprising opaque conductor." ¶55; p. 21 fig. col. 12:35-42
and at least one of the other electrodes comprises a transparent conductor. The pixel electrode is alleged to be a transparent conductor. A micrograph labels the "Pixel electrode comprising transparent conductor." ¶55; p. 21 fig. col. 12:43-44
  • Identified Points of Contention:
    • Technical Question: The complaint's visual evidence (Compl. ¶55) labels one electrode as comprising an "opaque conductor" and another a "transparent conductor." The case may turn on factual evidence establishing the material composition and optical properties (e.g., transmissivity) of these specific conductors in the accused device.
    • Scope Question: The ’829 Patent's specification links the "opaque conductor" to the function of shielding adverse electric fields from the signal line (’829 Patent, col. 3:28-32). The infringement analysis raises the question of whether the term should be construed to require this shielding function, or if merely being opaque is sufficient to meet the claim limitation.

V. Key Claim Terms for Construction

For the ’798 Patent

  • The Term: "differs... in a thickness"
  • Context and Importance: This term is the central point of novelty in claim 1. Its construction will determine whether any variation in thickness suffices, or if a specific type or degree of difference is required. Practitioners may focus on this term because the complaint’s evidence is a labeled diagram, and the dispute will center on whether the physical reality of the accused device meets the legal standard set by the claim's construction.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The claim language itself does not quantify the difference, suggesting any measurable variation could infringe. The patent states that the "geometrical shape of the electrode... includes the width and thickness of the electrode" (’798 Patent, col. 2:56-58), which supports a plain-meaning interpretation.
    • Evidence for a Narrower Interpretation: The specification repeatedly links changes in electrode geometry (including thickness) to achieving specific functional outcomes, such as changing wavelength dispersion characteristics to cancel coloring (’798 Patent, col. 4:42-51; claim 2). A defendant may argue that "differs... in a thickness" should be limited to differences that are substantial enough to achieve such a functional purpose.

For the ’829 Patent

  • The Term: "opaque conductor"
  • Context and Importance: The distinction between "opaque" and "transparent" conductors is the core of the invention claimed in the ’829 Patent. The definition of "opaque" will be critical to determining infringement, as it defines the required characteristic of the electrode adjacent to the signal lines.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The plain and ordinary meaning of "opaque" is not transmitting light. The specification does not provide an explicit definition that deviates from this meaning.
    • Evidence for a Narrower Interpretation: The abstract and detailed description link the opaque conductor to a specific function: suppressing the "adverse effects of the electric field formed between a signal line and an adjacent electrode" (’829 Patent, Abstract; col. 3:28-32). A defendant may argue that "opaque conductor" is not merely a material property but should be construed as a functional limitation, requiring that the conductor actually perform this shielding function in the accused device.

VI. Other Allegations

  • Indirect Infringement: For all asserted patents, the complaint alleges induced infringement under 35 U.S.C. § 271(b). The allegations are based on Defendant manufacturing the accused products and selling them to distributors, customers, and manufacturers (e.g., LGE) with the knowledge and intent that they would be imported, incorporated into end-products, and sold in the U.S. (Compl. ¶¶39-40, 57-58). Acts of inducement are alleged to include providing instructions, marketing materials, and marking the products with UL Solutions labels indicating compliance with U.S. laws and suitability for the U.S. market (Compl. ¶39).
  • Willful Infringement: For all asserted patents, the complaint alleges that infringement has been willful. This allegation is based on alleged pre-suit knowledge of the patents, imputed to Heesung through its business relationship with LG entities that allegedly received direct notice of infringement on multiple occasions, beginning in February 2017 (Compl. ¶¶38, 41, 56, 59). The complaint alleges that Defendant continued its infringing conduct despite this knowledge, disregarding an objectively high likelihood of infringement.

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

  • A central issue will be one of imputed knowledge: can Plaintiff establish that notice of infringement provided to Defendant’s alleged business partner and customer (LGE/LGD) constitutes legally sufficient knowledge for Defendant Heesung to be liable for indirect and willful infringement? The court will have to examine the nature of the business relationship to determine if knowledge can be transferred.
  • A key evidentiary question will be one of structural verification: the complaint’s infringement theories for all six patents rely heavily on visual analysis from a single exemplar product. The case will likely depend on whether discovery confirms that the specific microscopic structures—such as differing electrode thicknesses (’798 Patent), the use of opaque conductors for shielding (’829 Patent), and layered capacitors (’303 Patent)—are present across the accused product lines and operate as claimed.
  • The case will also present a question of process versus product: for the ’293 patent, which claims a method of manufacturing, can Plaintiff meet the evidentiary burden of proving that the accused products, which are sold in the U.S., were in fact made by the specific patented process (including a "rubbing" step) that occurred abroad?