BOE Technology Group Co Ltd v. Samsung Display Co Ltd

1. Case Identification

• Case #: IPR2025-01498
• Patent #: 10,720,483
• Filed: August 31, 2025
• Petitioner(s): BOE Technology Group Co., Ltd.
• Patent Owner(s): Samsung Display Co., Ltd.
• Challenged Claims: 1-29

2. Patent Overview

• Title: TFT Array Substrate and Organic Light-Emitted Display
• Brief Description: The ’483 patent discloses a thin film transistor (TFT) array substrate for an organic light-emitting diode (OLED) display. The technology aims to solve manufacturing problems from mask misalignment by including a storage capacitor structure that maintains a substantially constant capacitance despite overlay deviations.

3. Grounds for Unpatentability

Ground 1: Obviousness over Park - Claims 1, 11, 14, and 15 are obvious over Park.

• Prior Art Relied Upon: Park (Application # 2003/0141811).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Park, which discloses an active matrix OLED device, teaches all limitations of independent claim 1. Park describes a TFT array substrate with first and second TFTs (a driving transistor and a switching transistor), each having a channel region, a gate electrode, and an insulating layer. Park also discloses a multi-layer insulating structure and a metal pattern (anode and capacitor electrodes) overlapping the first gate electrode, as well as a connection member electrically connecting the first gate electrode to the second TFT. Petitioner further asserted that Park teaches the additional limitations of dependent claims 11 (driving voltage line connected to the first metal pattern through a contact hole), 14 (a gate line connected to the second gate electrode), and 15 (source and drain regions of the second TFT).
  • Motivation to Combine (for §103 grounds): This ground is based on a single reference. Petitioner contended that Park itself provides all necessary elements and motivations. Specifically, Park sought to increase storage capacitance without decreasing the aperture ratio, a problem addressed by the claimed invention. The structural elements disclosed in Park were arranged to achieve this goal, rendering the claimed combinations obvious.
  • Expectation of Success (for §103 grounds): Not applicable for a single-reference ground.

Ground 2: Obviousness over Park and Zhan - Claims 2-6, 22-24, and 27 are obvious over Park in view of Zhan.

• Prior Art Relied Upon: Park (Application # 2003/0141811) and Zhan (Application # 2011/0297941).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner contended that Park teaches most elements of the challenged claims, and Zhan supplies the remaining features. Specifically, for claim 2, Petitioner argued that while Park discloses a "first metal pattern," Zhan teaches forming this pattern with an opening and having a portion of a connection member overlap that opening in a plan view. Zhan discloses a divided second storage electrode with a contact hole in the center, which Petitioner equated to the claimed opening for improving device connectivity and capacitance.
  • Motivation to Combine (for §103 grounds): A POSITA would combine Park and Zhan because both are from the same field (OLED displays) and address the same technical problem of increasing storage capacitance without reducing aperture ratio. Petitioner asserted a POSITA would be motivated to incorporate Zhan’s technique of using a hole in a storage electrode to create a direct connection path into Park’s similar device to achieve greater capacitance and reduce manufacturing deviations.
  • Expectation of Success (for §103 grounds): A POSITA would have had a reasonable expectation of success because both references relate to improving storage capacitance and use connection members for inter-layer connections, and Zhan demonstrated a successful OLED configuration for this purpose.

Ground 3: Obviousness over Liu100 and Ono - Claims 1-4, 12-19, 22-24, 28, and 29 are obvious over Liu100 in view of Ono.

• Prior Art Relied Upon: Liu100 (Application # 2012/0313100) and Ono (Application # 2011/0128211).

• Core Argument for this Ground:

  • Prior Art Mapping: Petitioner argued that Liu100, which discloses a pixel structure for an OLED device with six TFTs, teaches the core structure of claim 1, including first and second TFTs, multiple insulating layers, and a connection member. To the extent Liu100 does not explicitly disclose a "first metal pattern" overlapping the first gate electrode, Petitioner argued Ono supplies this teaching. Ono discloses forming a capacitor in a region above a driving transistor, using the gate electrode as one of the capacitor electrodes and placing a second capacitor electrode (the "first metal pattern") over it.
  • Motivation to Combine (for §103 grounds): A POSITA would combine Liu100 and Ono to improve pixel density and capacitance. Both references address the efficient use of pixel space in OLED devices. A POSITA would have been motivated to apply Ono's technique of forming a capacitor over the driving transistor to the unoccupied space above the driving transistor in Liu100's layout. This would increase the total capacitance and improve display performance without increasing the pixel area.
  • Expectation of Success (for §103 grounds): Success was predictable because the combination merely involved applying Ono’s known space-saving capacitor structure to Liu100's layout, which had available space for this purpose. The modification only required a different mask pattern, not new layers or complex integration.

• Additional Grounds: Petitioner asserted additional obviousness challenges, including combinations of Park with Osame (to teach bent channel regions), Park with Ko (to teach pluralities of contact holes), and Park with Kwon (to teach additional gate lines and transistors). Further grounds were based on combinations of Liu100, Ono, Osame, and Liu080.

4. Arguments Regarding Discretionary Denial

• Fintiv Factors (§314(a)): Petitioner argued against discretionary denial under Fintiv, stating that no trial date has been set in the parallel district court litigation and that a Final Written Decision in this IPR would issue well before any potential trial. Petitioner also contended that the strong merits of the petition weigh in favor of institution.
• Same Art or Arguments (§325(d)): Petitioner argued that denial under §325(d) is inappropriate because none of the asserted prior art references (including Park, Zhan, Ono, and Liu100) were considered during the original prosecution of the ’483 patent. Therefore, the petition does not raise the same or substantially the same art or arguments previously presented to the Office.

5. Relief Requested

• Petitioner requests institution of inter partes review and cancellation of claims 1-29 of Patent 10,720,483 as unpatentable.