DCT

1:25-cv-02021

Tianma Microelectronics Co Ltd v. LG Display Co Ltd

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Key Events
Complaint

I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 1:25-cv-02021, W.D. Tex., 12/09/2025
  • Venue Allegations: Plaintiff alleges venue is proper for LG Display Co., Ltd. as a foreign corporation that may be sued in any judicial district. Venue for LG Display America, Inc. is based on allegations that it has committed acts of infringement in the district and maintains a regular and established place of business in Austin, Texas.
  • Core Dispute: Plaintiff alleges that Defendant’s TFT-LCD and OLED display panels infringe four U.S. patents related to thin-film transistor structures, touch-display panel configurations, OLED manufacturing processes, and high-resolution pixel arrangements.
  • Technical Context: The technology at issue involves the micro-architectures of advanced display panels, a critical component in the highly competitive global market for consumer electronics and automotive systems.
  • Key Procedural History: The complaint alleges a long history of licensing discussions and technical exchanges between the parties, including a virtual meeting on March 24, 2021, where Plaintiff allegedly put Defendant on notice of infringement of at least one of the patents-in-suit.

Case Timeline

Date Event
2011-08-12 U.S. Patent No. 8,785,925 Priority Date
2014-07-22 U.S. Patent No. 8,785,925 Issued
2015-09-02 U.S. Patent No. 12,293,691 Priority Date
2016-05-06 U.S. Patent No. 10,234,971 Priority Date
2018-08-10 U.S. Patent No. 10,770,525 Priority Date
2019-03-19 U.S. Patent No. 10,234,971 Issued
2020-09-08 U.S. Patent No. 10,770,525 Issued
2021-03-24 Plaintiff allegedly notifies Defendant of '925 Patent infringement
2025-05-06 U.S. Patent No. 12,293,691 Issued
2025-12-09 Complaint Filing Date

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

U.S. Patent No. 8,785,925, “Thin Film Device,” issued July 22, 2014

The Invention Explained

  • Problem Addressed: The patent's background describes how conventional thin-film transistors (TFTs) using oxide semiconductors can suffer from performance degradation when an "oxygen deficit layer" forms on the semiconductor surface during the manufacturing process, particularly during plasma etching of the source/drain electrodes, leading to increased off-current (’925 Patent, col. 2:5-13).
  • The Patented Solution: The invention proposes a TFT structure where the manufacturing process itself creates a specialized "surface layer" in the exposed region of the oxide semiconductor film between the source and drain electrodes. This surface layer is described as containing at least fluorine or chlorine, which is introduced during the plasma etching of the electrodes, and is intended to suppress the formation of the problematic oxygen deficit layer (’925 Patent, Abstract; col. 3:35-49).
  • Technical Importance: This approach aimed to improve the stability and performance of oxide semiconductor TFTs, a key enabling technology for high-resolution and low-power displays, by addressing a fundamental manufacturing side-effect without requiring additional process steps like acid etching (’925 Patent, col. 2:50-62).

Key Claims at a Glance

  • The complaint asserts at least independent claim 1 (Compl. ¶62).
  • Essential elements of claim 1 include:
    • A gate electrode, gate insulating film, oxide semiconductor film, and a source/drain electrode arranged in a standard TFT stack.
    • A "surface layer" that contains a composition element of the oxide semiconductor film, a composition element of a part of the source/drain electrode in contact with the film, and at least either fluorine or chlorine.
    • This surface layer must "exist in a part of the oxide semiconductor film where the source/drain electrode is not superimposed."
  • The complaint does not explicitly reserve the right to assert dependent claims.

U.S. Patent No. 10,234,971, “Touch-Display Panel and Touch-Display Device,” issued March 19, 2019

The Invention Explained

  • Problem Addressed: In display panels with integrated touch sensors, the conductive touch signal traces running through the display area limit the placement options for "spacers" (also called support pillars), which are critical for maintaining a uniform gap between the two glass substrates. This restriction can lead to some spacers being placed on top of traces and others not, causing uneven cell thickness and resulting in "abnormality in colors" and degraded display quality (’971 Patent, col. 1:32-44).
  • The Patented Solution: The invention introduces "a plurality of dummy touch signal wires" alongside the functional touch signal wires. These dummy wires are not connected to the control circuitry but are strategically placed to provide additional, structurally similar locations for spacers. This allows spacers to be distributed more uniformly across both functional and dummy wires, solving the uneven thickness problem and improving display consistency (’971 Patent, col. 2:5-14).
  • Technical Importance: This design provides a practical manufacturing solution for in-cell touch displays, enhancing yield and visual performance by decoupling spacer placement from the functional touch trace layout (’971 Patent, col. 2:5-14).

Key Claims at a Glance

  • The complaint asserts at least independent claim 1 (Compl. ¶83).
  • Essential elements of claim 1 include:
    • A first and second substrate, a touch electrode layer, a touch signal wire layer, spacers, and a control circuit.
    • The touch signal wire layer includes both a "plurality of touch signal wires" and a "plurality of dummy touch signal wires."
    • Each dummy wire has an orthographic projection located within the area of a single touch electrode.
    • The spacers are arranged such that at least one spacer's projection overlaps with a touch signal wire, and at least another spacer's projection overlaps with a dummy touch signal wire.
  • The complaint does not explicitly reserve the right to assert dependent claims.

U.S. Patent No. 10,770,525, “Organic Light-Emitting Display Panel, Display Device, and Fabrication Method Thereof,” issued September 8, 2020

  • Technology Synopsis: The patent addresses reliability and yield problems in OLED manufacturing related to the use of evaporation masks to deposit common layers. It discloses a system of "support units" located in the non-display region of the panel to physically support the mask during deposition, thereby preventing the mask from scratching or damaging underlying film layers and improving product yield (Compl. ¶¶52-54; ’525 Patent, Abstract). The invention specifies the placement of these support units, including on "island structures" of the pixel defining layer and within or outside the projection of the cathode (Compl. ¶¶53-54).
  • Asserted Claims: At least claim 7 (Compl. ¶106).
  • Accused Features: The complaint alleges that the LG Display 13.4-inch OLED panel (model LP134WT1) incorporates the claimed structure, including a plurality of support units disposed in the non-display region as specified by the patent (Compl. ¶¶107, 109).

U.S. Patent No. 12,293,691, “Display Device and Luminance Allocation Method,” issued May 6, 2025

  • Technology Synopsis: The patent is directed to the pixel architecture in high-resolution OLED displays that use two different pixel types arranged alternately in a checkerboard-like pattern. The invention teaches a specific, biased arrangement for the subpixels and for the "connection part" that links the TFT circuit to the subpixel. This specific placement is intended to maintain consistent spacing and proper overlap between layers (e.g., anode and OLED layers) across the different pixel types, which is critical for manufacturing consistency and performance (Compl. ¶58; ’691 Patent, Abstract).
  • Asserted Claims: At least claim 1 (Compl. ¶121).
  • Accused Features: The complaint alleges the LG Display 13.4-inch OLED panel (model LP134WT1) utilizes the claimed pixel array, including the distinct first and second pixel types with subpixels and connection parts arranged in the specific biased configuration taught by the patent (Compl. ¶¶122, 127-132).

III. The Accused Instrumentality

Product Identification

The complaint identifies the "Accused Products" as TFT-LCD and OLED display panels and modules manufactured by LG Display (Compl. ¶9). Specific exemplary products identified are the LG 27-inch UltraGear Nano IPS 4K Gaming Monitor (27GP950-B), the Tesla 15.4-inch LTPS in-cell display, and the LG Display 13.4-inch OLED panel (LP134WT1) (Compl. ¶¶9, 62, 83, 106, 121).

Functionality and Market Context

The accused products are core components for a wide range of electronic devices, including high-performance gaming monitors and automotive displays for major customers like Tesla (Compl. ¶¶9, 34). The infringement allegations focus on the microscopic physical structures within these panels, such as the composition of transistor layers, the layout of touch-sensing wires and spacers, the arrangement of support structures in non-display areas, and the precise geometry of pixel and subpixel layouts (Compl. ¶¶63-67, 85-89, 107-109, 122-134). The complaint positions the defendants as direct competitors who incorporate these patented technologies into products sold in significant commercial markets, including in the Western District of Texas (Compl. ¶¶6, 7, 34). The complaint provides an annotated microscopy image showing the projection of spacers overlapping with both functional and "dummy" touch signal wires in the accused Tesla display (Compl. p. 26).

IV. Analysis of Infringement Allegations

U.S. Patent No. 8,785,925 Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
a gate electrode on a substrate, a gate insulating film on the gate electrode, an oxide semiconductor film on the gate insulating film, and a source/drain electrode on the oxide semiconductor film The accused LG monitor panel is alleged to include this standard TFT stack, as shown in a cross-sectional TEM image identifying the substrate, gate electrode, gate insulating film, and oxide semiconductor film (Compl. p. 17). A source/drain electrode is shown on the oxide semiconductor film (Compl. p. 18). ¶63, ¶64 col. 3:40-45
a surface layer contains a composition element of the oxide semiconductor film, a composition element of a part of the source/drain electrode in contact with the oxide semiconductor film... The complaint alleges the existence of a "surface layer" and presents EDX spectroscopy data purporting to show that this layer contains elements from both the oxide semiconductor film (In, Ga, Zn, O) and the source/drain electrode (Ti, Mo) (Compl. p. 19). The complaint provides a TEM image labeling this "surface layer" (Compl. p. 18). ¶65, ¶66 col. 3:45-49
...and at least either fluorine or chlorine exist in a part of the oxide semiconductor film where the source/drain electrode is not superimposed. Time-of-Flight Secondary Ion Mass Spectrometry (TOF-SIMS) data is presented to demonstrate that fluorine (F) and chlorine (Cl) are present in the oxide semiconductor film in an area not covered by the source/drain electrode (Compl. p. 20). ¶67 col. 3:45-49
  • Identified Points of Contention:
    • Scope Questions: A central question may be the definition of "surface layer." The dispute may focus on whether the intermixed region identified in the accused product constitutes a distinct "layer" as contemplated by the patent, or is merely a transitional interface inherent in the manufacturing process.
    • Technical Questions: What evidence does the complaint provide that the identified "surface layer" is a single, integral feature containing all three required components (semiconductor elements, electrode elements, and fluorine/chlorine)? The complaint uses separate analyses (EDX and TOF-SIMS) for elemental composition and the presence of halogens, which may raise questions about whether these elements coexist in the same claimed "layer."

U.S. Patent No. 10,234,971 Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
a first substrate and a second substrate disposed opposite with each other; a touch electrode layer provided on the first substrate and comprising a plurality of touch electrodes... The accused Tesla in-cell display is alleged to be a touch-display panel with first and second substrates and a touch electrode layer (Compl. p. 26). ¶85, ¶86 col. 3:1-4
a touch signal wire layer, including... a plurality of touch signal wires, and a plurality of dummy touch signal wires, wherein each dummy touch signal wire... has an orthographic projection... located within an area of one touch electrode... The accused product is alleged to include both "touch signal wires" (aqua) and "dummy touch signal wires" (yellow), with the dummy wires located within the area of a touch electrode as shown in an annotated diagram (Compl. p. 26). ¶87, ¶88 col. 3:4-10
a plurality of spacers provided on a surface of the second substrate... wherein... at least one first orthographic projection overlaps with at least one touch signal wire... and at least another first orthographic projection overlaps with at least one dummy touch signal wire... An annotated diagram alleges that projections of the spacers (blue/green) in the accused product overlap with both the functional touch signal wires (aqua) and the dummy touch signal wires (yellow) (Compl. p. 26). ¶89 col. 3:10-14
a control circuit configured to provide touch signals to each touch electrode of the plurality of touch electrodes; wherein each touch signal wire... electrically connects one touch electrode... with the control circuit... The complaint identifies a "Control circuit" on the rear of the panel and alleges that the touch signal wires connect the touch electrodes to this circuit (Compl. p. 27). ¶90, ¶91 col. 3:15-18
  • Identified Points of Contention:
    • Scope Questions: The construction of "dummy touch signal wires" will be critical. The patent requires that they do not electrically connect the touch electrode with the control circuit. A potential dispute is whether the structures identified as "dummy" wires in the accused product meet this negative limitation and are present for the purpose of spacer support, or if they have another electrical function (e.g., shielding) or are non-functional manufacturing artifacts.
    • Technical Questions: Does the complaint provide sufficient evidence that the projection of spacers overlaps with both wire types in a manner that is systematic and intentional for providing even cell thickness, as the patent teaches? The infringement analysis may turn on the statistical distribution and purpose of this overlap across the entire display panel, rather than just the area shown in the complaint's diagram.

V. Key Claim Terms for Construction

'925 Patent

  • The Term: "surface layer"
  • Context and Importance: This term defines the core inventive concept. The infringement analysis hinges on whether the accused device has this specific layer, defined by its location, its composite nature (containing elements from both the semiconductor and the electrode), and the presence of a halogen. Practitioners may focus on this term because its structural and compositional definition is the primary point of differentiation from prior art.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: Claim 1 uses the word "contains," which may support an interpretation that the layer is a mixture or an inter-diffusion zone rather than a distinct, separately formed layer with a defined stoichiometry. The specification notes the layer is formed "at the time of" etching the electrode, suggesting it is a byproduct of a single process step (Compl. ¶67; ’925 Patent, col. 4:58-65).
    • Evidence for a Narrower Interpretation: The patent consistently refers to it as a "layer," which may suggest a feature with a discernible thickness and boundary, as depicted in the complaint’s own diagrams (Compl. p. 18). The abstract states the "surface layer... exists," which could be argued to imply a distinct feature rather than just a modified region of the original semiconductor film.

'971 Patent

  • The Term: "dummy touch signal wires"
  • Context and Importance: This term is the central feature of the invention claimed in the '971 patent. Whether the accused device infringes will depend on whether certain non-functional conductive traces within its structure meet the definition of "dummy touch signal wires." Practitioners may focus on this term because its definition must distinguish it from both functional signal lines and incidental, non-functional manufacturing remnants.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The specification defines the term primarily by its function (or lack thereof): the wires "would not render the touch electrodes ... and the control circuit ... electrically connected, and that the dummy touch signal wires ... would not transmit touch signals" (’971 Patent, col. 4:50-57). This could be argued to cover any conductive line that is not part of the active touch-sensing circuit but is available for spacer support.
    • Evidence for a Narrower Interpretation: The patent describes the dummy wires as being provided "so as to increase the flexibility of distribution of the spacers" (’971 Patent, col. 2:7-9). A defendant may argue that to meet this definition, the wires must be shown to have been intentionally designed and placed for that specific purpose, rather than being present for other reasons (e.g., as ground lines or for process uniformity) with any spacer overlap being merely incidental.

VI. Other Allegations

  • Indirect Infringement: The complaint alleges both induced and contributory infringement for all asserted patents. Inducement is based on allegations that Defendant promoted, advertised, and provided instructions for the Accused Products, encouraging infringing use by customers (Compl. ¶¶71, 94). Contributory infringement is based on allegations that Defendant sells key components (e.g., the specific TFTs or touch-panel structures) that are not staple articles of commerce and are known to be used in an infringing manner (Compl. ¶¶72, 95).
  • Willful Infringement: The complaint alleges willful infringement for all asserted patents. For the '925 patent, willfulness is predicated on alleged pre-suit knowledge dating back to at least a March 24, 2021 meeting and potentially as early as 2012, based on a "decade-long pattern of negotiations" (Compl. ¶¶68, 69, 73). For the other patents, willfulness is based on Defendant’s alleged actual knowledge from its industry position, its sophisticated engineering teams, and the parties’ history of licensing discussions (Compl. ¶¶92, 96, 110, 114, 135, 139).

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

  • A core issue will be one of material characterization: Does the interface region in LG's accused TFTs constitute the specific multi-element "surface layer" containing fluorine or chlorine, as required by the '925 patent? The case may turn on a highly technical, evidence-intensive dispute over the interpretation of microscopy and spectroscopy data.
  • A key question will be one of functional purpose: Do the non-signal-carrying conductive lines in the accused touch displays function as "dummy touch signal wires" designed to solve the spacer-placement problem as taught by the '971 patent, or is their structural similarity and any overlap with spacers incidental to a different design purpose?
  • A significant legal question will be one of pre-suit knowledge: Will the alleged history of general licensing discussions and technical exchanges between these two major industry competitors be sufficient to establish that the defendant acted willfully with respect to the specific technologies claimed in the four asserted patents, potentially exposing it to enhanced damages?