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: Thin Film Transistor Array Substrate
• Brief Description: The ’483 patent discloses a thin film transistor (TFT) array substrate, particularly for an organic light-emitting diode (OLED) display. The technology is directed to a specific storage capacitor structure intended to maintain a substantially constant capacitance, even in the presence of manufacturing misalignments (overlay deviation), to prevent display defects like low-gradation spots or abnormal colors.

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 electro-luminescence display device, teaches all elements of the independent and dependent claims in this ground. Petitioner asserted that Park’s device includes a TFT array substrate with a first driving TFT and a second switching TFT, each comprising a channel region and gate electrode separated by a first insulating layer. Park was also alleged to disclose the claimed second and third insulating layers, a first metal pattern (a capacitor electrode) that overlaps the first gate electrode, and a connection member that electrically links the first gate electrode to the second TFT.
  • Motivation to Combine (for §103 grounds): As a single-reference ground under 35 U.S.C. §103, Petitioner’s argument implied that Park’s disclosure was so comprehensive that it rendered the claimed invention obvious without combination.

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), Zhan (Application # 2011/0297941).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner contended that Park provides the base TFT array substrate as recited in claim 1. Zhan was introduced to supply the limitations of dependent claim 2, specifically teaching a "first metal pattern" (e.g., a storage electrode) that includes an opening, and a "connection member" that overlaps this opening. Zhan discloses a divided storage electrode with a central contact hole to facilitate a direct connection to another layer, which Petitioner argued maps directly onto the claim limitations.
  • Motivation to Combine (for §103 grounds): A POSITA would combine Park with Zhan to solve the common problem of increasing storage capacitance without decreasing the pixel aperture ratio. Petitioner argued that Zhan’s technique of using a contact hole through a divided electrode was a known and advantageous method for improving interconnections and capacitance, which a POSITA would logically apply to Park’s similar device to achieve the same benefit.
  • Expectation of Success (for §103 grounds): Success would be reasonably expected because both references are in the same technical field of OLED displays, address identical problems, and the proposed modification involves applying a known interconnection technique from Zhan to the analogous structure in Park.

Ground 3: Obviousness over Park and Osame - Claims 7-10 are obvious over Park in view of Osame.

• Prior Art Relied Upon: Park (Application # 2003/0141811), Osame (Application # 2003/0222589).

• Core Argument for this Ground:

  • Prior Art Mapping: Petitioner argued that Park teaches the foundational elements of claim 1. Osame was asserted to teach the specific channel geometries recited in dependent claims 7-10, which require the first channel region to have a "bent portion," be curved in an "S' shape," or be curved in a "zigzag shape." Osame explicitly discloses forming the semiconductor layer of a driving TFT in such meandering shapes.
  • Motivation to Combine (for §103 grounds): A POSITA would be motivated to modify Park’s driving transistor with Osame’s channel shapes to increase the effective channel length without enlarging the transistor’s footprint. This known technique improves current stability and overall image quality while preserving a high aperture ratio, a key objective in the field.
  • Expectation of Success (for §103 grounds): The combination represented a simple substitution of a known element (a straight channel) with a well-understood alternative (a meandering channel) to obtain the predictable result of improved electrical performance without compromising pixel density.

• Additional Grounds: Petitioner asserted additional obviousness challenges based on combinations including Park/Zhan/Osame, Park/Ko, Park/Zhan/Ko, Park/Kwon, Liu100/Ono, Liu100/Ono/Osame, and Liu100/Ono/Liu080, which relied on similar rationales of combining known prior art elements for their established and predictable functions.

4. Arguments Regarding Discretionary Denial

• The petition argued against discretionary denial under §314(a) and the Fintiv factors, asserting that no schedule or trial date had been set in the parallel district court litigation. Petitioner contended that a Final Written Decision would therefore issue well before any potential trial.
• The petition also argued that denial under §325(d) would be inappropriate because none of the prior art references or invalidity arguments presented were the same or substantially the same as those considered by the USPTO during the original prosecution of the ’483 patent.

5. Relief Requested

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