DCT

2:23-cv-00309

Samsung Display Co Ltd v. BOE Technology Co Ltd

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 2:23-cv-00309, E.D. Tex., 06/28/2023
  • Venue Allegations: Venue is alleged to be proper on the basis that Defendants are foreign corporations that do not reside in the United States and may be sued in any judicial district.
  • Core Dispute: Plaintiff alleges that Defendant’s Organic Light Emitting Diode (OLED) displays infringe five U.S. patents related to pixel driving circuitry, scan driver stage circuits, and specific pixel arrangement structures.
  • Technical Context: The dispute centers on core technologies for modern high-resolution OLED displays, which are critical components in premium consumer electronics such as smartphones.
  • Key Procedural History: The complaint alleges Defendants had pre-suit knowledge of four of the five asserted patents via a notice letter sent on May 2, 2022. It further references a U.S. International Trade Commission (ITC) investigation (No. 337-TA-1351) initiated by Plaintiff in December 2022, in which Defendant Mianyang BOE intervened in February 2023, allegedly acknowledging the risk of an exclusion order based on the asserted patents. Knowledge of the fifth patent is alleged from a March 2023 motion to amend the ITC complaint.

Case Timeline

Date Event
2003-07-07 ’599 Patent Priority Date
2008-08-19 ’599 Patent Issue Date
2012-03-06 ’803, ’683, & ’578 Patents Priority Date
2012-09-20 ’593 Patent Priority Date
2016-05-03 ’593 Patent Issue Date
2017-11-14 ’803 Patent Issue Date
2020-12-01 ’683 Patent Issue Date
2022-05-02 Samsung sends notice letter to BOE regarding ’599, ’593, ’803, and ’683 Patents
2022-12-28 Samsung files ITC complaint
2023-02-28 Mianyang BOE moves to intervene in ITC investigation
2023-02-28 ’578 Patent Issue Date
2023-03-10 Samsung moves to add ’578 Patent to ITC complaint
2023-06-28 Complaint Filing Date

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

U.S. Patent No. 7,414,599 - "Organic Light Emitting Device Pixel Circuit and Driving Method Thereof," Issued 08/19/2008

The Invention Explained

  • Problem Addressed: The patent's background describes how active-matrix OLED (AMOLED) displays can suffer from "display nonuniformity." This problem arises from variations in the threshold voltage of the thin film transistors (TFTs) that drive each pixel, which occur due to inconsistencies in the manufacturing process. These variations cause different pixels to emit different amounts of light even when given the same data signal, resulting in an uneven image. (’599 Patent, col. 1:40-50).
  • The Patented Solution: The invention proposes a novel pixel circuit designed to automatically compensate for these threshold voltage variations. The circuit uses a specific arrangement of transistors, including a "third transistor" that connects the driving transistor "in the form of a diode" during a programming phase. This configuration allows the circuit to detect and offset the driving transistor's specific threshold voltage, ensuring a uniform driving current and consistent light emission across the display. (’599 Patent, Abstract; col. 6:35-42).
  • Technical Importance: Such self-compensating pixel circuits were a critical development for enabling the mass production of large, high-quality, and long-lasting AMOLED displays for consumer devices. (’599 Patent, col. 2:7-10).

Key Claims at a Glance

  • The complaint asserts independent claim 1 (Compl. ¶31).
  • Claim 1 Elements:
    • A pixel circuit in an organic light emitting device comprising:
    • a first transistor for delivering a data signal voltage;
    • a second transistor for generating a driving current;
    • a third transistor for detecting and self-compensating threshold voltage deviation in the second transistor;
    • a fifth transistor for providing a power supply voltage to the second transistor;
    • a sixth transistor coupled in series with the second transistor for providing the driving current to an electroluminescent element;
    • a capacitor for storing the data signal voltage;
    • wherein the electroluminescent element emits light corresponding to the driving current.

U.S. Patent No. 9,330,593 - "Stage Circuit and Organic Light Emitting Display Using the Same," Issued 05/03/2016

The Invention Explained

  • Problem Addressed: The patent addresses the design of "stage circuits," which are fundamental building blocks of the scan drivers that select rows of pixels in a display. The background section notes the general architecture of displays using data drivers and scan drivers to address individual pixels. (’593 Patent, col. 1:33-44). The invention aims to provide an improved stage circuit design.
  • The Patented Solution: The invention discloses a stage circuit with a specific architecture comprising an "outputting unit," a "first driver," and a "second driver." A key feature is that a signal from a "third input terminal" is claimed to "directly control" the on/off operation of a transistor within the first driver. This configuration allows for precise control over the circuit's nodes to generate a stable output signal for the scan line. (’593 Patent, Abstract; col. 4:8-16).
  • Technical Importance: Efficient and reliable stage circuits are essential for high-speed, low-power operation of display drivers, which in turn enables higher refresh rates and can contribute to product designs with smaller bezels. (’593 Patent, col. 2:49-52).

Key Claims at a Glance

  • The complaint asserts independent claim 1 (Compl. ¶58).
  • Claim 1 Elements:
    • A stage circuit with first, second, third input terminals and an output terminal, comprising:
    • an outputting unit with a first and second node to supply a voltage to the output terminal;
    • a first driver to control the voltage of the second node based on signals from the first, second, and third input terminals;
    • a second driver to control the voltage of the first node based on the signal of the second input terminal and voltage of the second node;
    • wherein the signal of the third input terminal directly controls an on/off operation of a transistor included in the first driver.

U.S. Patent No. 9,818,803 - "Pixel Arrangement Structure for Organic Light Emitting Display Device," Issued 11/14/2017

  • Technology Synopsis: This patent addresses the physical layout of sub-pixels on a display. The invention describes a specific geometric arrangement of a "first pixel," "second pixel," and "third pixel" relative to the center and vertices of a "virtual square" to improve aperture ratio while maintaining deposition reliability during manufacturing ('803 Patent, Abstract; col. 1:42-51).
  • Asserted Claims: Independent claim 1 (Compl. ¶79).
  • Accused Features: The complaint accuses the specific geometric layout, relative sizing, and color configuration (e.g., the first pixel emitting green light) of the sub-pixels in BOE's OLED displays (Compl. ¶¶85-90).

U.S. Patent No. 10,854,683 - "Pixel Arrangement Structure for Organic Light Emitting Display Device," Issued 12/01/2020

  • Technology Synopsis: As a continuation of the '803 Patent, this patent also concerns pixel layouts. The invention defines a pixel structure based on the arrangement of a "first pixel," a "pair of second pixels," and a "pair of third pixels" located along two distinct, crossing lines. The claims include limitations on the relative distances between these pixels and their relative sizes ('683 Patent, Abstract; col. 2:3-15).
  • Asserted Claims: Independent claim 1 (Compl. ¶99).
  • Accused Features: The complaint alleges that the arrangement of green, red, and blue sub-pixels in BOE's displays, including their linear alignment and relative spacing, infringes the claimed structure (Compl. ¶¶105-112).

U.S. Patent No. 11,594,578 - "Pixel Arrangement Structure for Organic Light Emitting Display Device," Issued 02/28/2023

  • Technology Synopsis: This patent, a continuation of the '683 Patent, further refines the geometric constraints for a pixel layout. The claims describe pluralities of first, second, and third pixels arranged in sets forming parallel and perpendicular lines, with specific requirements for how these lines are arranged, how they pass through pixel centers, and how regions containing pixel rows are offset from one another ('578 Patent, col. 1:56-col. 2:24).
  • Asserted Claims: Independent claim 1 (Compl. ¶121).
  • Accused Features: The complaint accuses the grid-like arrangement of sub-pixels in BOE's displays of meeting the patent's detailed requirements for alternately arranged sets of pixels in perpendicular directions (Compl. ¶¶131-140).

III. The Accused Instrumentality

Product Identification

  • The Accused Products are OLED displays manufactured, used, sold, offered for sale, or imported by Defendants. The complaint specifically identifies OLED displays incorporated into smartphones, tablets, and other mobile devices, with a particular focus on those supplied for the Apple iPhone 12 (Compl. ¶¶24, 30, 32).

Functionality and Market Context

  • The accused devices are display panels comprising a substrate that supports OLED pixel elements and the circuitry that controls their operation (Compl. ¶34). The complaint alleges that Defendant BOE Beijing is an Apple supplier and that market reports indicate BOE supplies OLED display panels for Apple's iPhone 12 and 13 models sold in the United States (Compl. ¶27). The complaint provides an annotated image from a teardown of an iPhone 12, identifying the "Display Panel Substrate" supplied by Defendants (Compl. ¶34, Fig. 4).

IV. Analysis of Infringement Allegations

’599 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
a first transistor for delivering a data signal voltage in response to a current scan line signal Transistor T2 is coupled to a data signal line (Dm) and its gate is coupled to a scan line (Sn), delivering a data signal voltage in response to the scan line signal. ¶36 col. 5:29-37
a second transistor for generating a driving current depending on the data signal voltage delivered through the first transistor Transistor T1 generates a driving current from a power supply (ELVDD), where the amount of current is determined by the voltage stored on capacitor Cst, which is based on the data signal delivered by T2. ¶38 col. 5:38-42
a third transistor for detecting and self-compensating threshold voltage deviation in the second transistor Transistor T3 is coupled between the drain and gate of the second transistor (T1) to allow for detection and self-compensation of threshold voltage deviation in T1. ¶40 col. 5:61-65
a fifth transistor for providing a power supply voltage for the second transistor in response to a current light-emitting signal Transistor T5 is coupled to the power supply (ELVDD) and second transistor (T1), and is controlled by a light-emitting signal on the emission line (En) to provide the power supply voltage to T1. ¶42 col. 6:11-17
a sixth transistor which is coupled in series between the second transistor and an electroluminescent element and for providing the driving current... Transistor T6 is coupled in series between the second transistor (T1) and the OLED element. It is controlled by the light-emitting signal (En) to provide the driving current for the OLED through T1. ¶44 col. 6:18-26
a capacitor for storing the data signal voltage delivered to the second transistor A storage capacitor (Cst) stores the data signal voltage that is delivered to the second transistor (T1). ¶46 col. 6:6-10

Identified Points of Contention

  • Functional Questions: The complaint provides detailed annotated micrographs, such as the backside image of the pixel circuit in Figure 5 (Compl. ¶35), to map physical structures to claim elements. A potential point of contention may be whether these structures perform the claimed functions. For example, what evidence demonstrates that the accused transistor T3 actually performs the function of "detecting and self-compensating threshold voltage deviation" during the device's operation, as opposed to merely being structurally present?
  • Scope Questions: Claim 1 recites a "fifth" and "sixth" transistor but omits a "fourth." While the patent specification discloses an embodiment with a fourth transistor, its absence from the claim raises the question of whether the claim requires a specific number of transistors or merely the presence of transistors performing the recited functions, regardless of their label.

’593 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
an outputting unit having a first node and a second node, the outputting unit to supply a voltage... The outputting unit, comprising transistors T4 and T5, supplies a voltage from a first power supply (VGH) or a signal from a third input terminal (IN3) to the output terminal (OUT1) depending on voltages at its first and second nodes. ¶64-65 col. 4:16-25
a first driver to control the voltage of the second node in accordance with signals of the first input terminal, the second input terminal, and the third input terminal A first driver, comprising transistors T1, T2, and T3, controls the voltage of the second node (e.g., at the gate of T5) based on signals applied to input terminals IN1, IN2, and IN3. ¶66 col. 3:6-14
a second driver to control the voltage of the first node in accordance with the signal of the second input terminal and the voltage of the second node A second driver, comprising transistors T6 and T7, controls the voltage of the first node (e.g., at the gates of T3 and T4) based on the signal at the second input terminal (IN2) and the voltage of the second node. ¶68 col. 3:15-20
wherein the signal of the third input terminal directly controls an on/off operation of a transistor, the transistor included in the first driver The signal from the third input terminal (IN3) is coupled to the gate of transistor T2, which is part of the first driver, and directly controls its on/off operation. The complaint shows this coupling in Figure 33. ¶70 col. 4:32-36

Identified Points of Contention

  • Scope Questions: The infringement analysis may focus on the term "directly controls." The complaint alleges the signal from input IN3 is coupled to the gate of transistor T2 (Compl. ¶70, Fig. 33). A key question for the court will be the scope of "directly." Does it preclude any intervening passive components, or does it mean not being controlled through another active switching element?
  • Technical Questions: The complaint identifies functional blocks like the "first driver" and "outputting unit" based on annotated micrographs of the accused display's scan driver (Compl. ¶62, Fig. 28). A potential dispute could arise over whether these physical groupings of transistors in the accused product operate in the specific manner required to meet the functional definitions of these units as claimed in the patent.

V. Key Claim Terms for Construction

For the ’599 Patent

  • The Term: "self-compensating threshold voltage deviation"
  • Context and Importance: This term defines the core purpose and function of the third transistor and is central to the invention's value. The construction of this term will determine the functional standard that the accused product's circuit must meet. Practitioners may focus on whether this requires a specific mechanism of compensation or covers any circuit that achieves a compensating effect.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The Summary of the Invention describes the goal more generally as providing a pixel circuit "capable of detecting and self-compensating threshold voltage deviations" without being limited to one specific mechanism (’599 Patent, col. 3:45-48).
    • Evidence for a Narrower Interpretation: The detailed description explains that this function is achieved when the third transistor "connects the second transistor in the form of a diode," which allows the circuit to "self-compensate a threshold voltage of the second transistor" (’599 Patent, col. 4:35-42). This suggests the mechanism of compensation is integral to the term's meaning.

For the ’593 Patent

  • The Term: "directly controls"
  • Context and Importance: This term appears in the final "wherein" clause of claim 1, which often serves as a critical point of distinction over the prior art. Infringement will likely depend on whether the connection between the third input terminal and the transistor in the accused circuit is deemed "direct."
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The specification may not provide an explicit definition, which could support an interpretation based on the plain and ordinary meaning, i.e., control that is not substantially indirect or mediated by another active component.
    • Evidence for a Narrower Interpretation: The patent's figures, such as Figure 3, show a direct conductive line from the input terminal (corresponding to CLK2) to the gate of the relevant transistor (M2) (’593 Patent, Fig. 3). This embodiment may be used to argue that "directly" requires a physical, uninterrupted connection to the gate electrode.

VI. Other Allegations

Indirect Infringement

The complaint alleges both induced and contributory infringement for all asserted patents. The factual basis for inducement is the allegation that Defendants sell their OLED displays to customers (e.g., Apple) with the knowledge and specific intent that these customers will incorporate them into end-products (e.g., iPhone 12) that are imported, used, and sold in the U.S., thereby directly infringing the patents (Compl. ¶¶52-53, 73-74). Contributory infringement is alleged on the basis that the accused displays are especially designed to practice the patented inventions and have no substantial non-infringing uses (Compl. ¶¶54, 75).

Willful Infringement

Willfulness is alleged for all patents based on pre-suit knowledge. The complaint alleges that Defendant BOE Beijing received a notice letter on May 2, 2022, identifying the ’599, ’593, ’803, and ’683 Patents (Compl. ¶22). Knowledge of all five patents is further alleged based on Defendant Mianyang BOE's intervention in a related ITC investigation where it acknowledged the infringement risk (Compl. ¶¶23, 55). Knowledge of the ’578 Patent is also alleged based on Plaintiff’s motion to add it to the ITC case on March 10, 2023 (Compl. ¶23).

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

  • A core issue will be one of functional proof: For the circuit-level patents (’599 and ’593), the complaint provides extensive structural evidence by mapping claim elements to features in micrographs. A central question will be evidentiary: what proof will be required to demonstrate that these identified structures actually operate in the manner claimed (e.g., performing "self-compensation" or "direct control")?
  • A second key question will be one of geometric scope: For the pixel arrangement patents (’803, ’683, and ’578), the dispute will likely center on claim construction and factual application. Can the abstract geometric concepts of the claims, such as a "virtual square" or a "line defined by the center," be definitively and non-ambiguously mapped onto the physical, real-world layout of the sub-pixels in the accused displays?
  • A third question concerns knowledge and intent: The complaint alleges multiple instances of pre-suit notice, including a formal letter and admissions in a related ITC proceeding. This raises a key question for willfulness and indirect infringement: how will Defendants counter the strong factual allegations of pre-suit knowledge of their alleged infringement?