Samsung Display Co Ltd v. Pictiva Displays Intl Ltd

1. Case Identification

• Case #: IPR2026-00129
• Patent #: 12,158,250
• Filed: November 18, 2025
• Petitioner(s): Samsung Display Co., Ltd.
• Patent Owner(s): Pictiva Displays International Ltd.
• Challenged Claims: 1-16

2. Patent Overview

• Title: Organic Light Emitting Diode Device
• Brief Description: The ’250 patent discloses an organic light-emitting diode (OLED) device. The device features an organic layer sequence that includes an n-doped electron transport layer (ETL), an emission layer containing an iridium compound, and an encapsulation to seal the device from environmental influences.

3. Grounds for Unpatentability

Ground 1: Obviousness over Suzuki and Ma - Claims 1-2, 4-5, 8-10 are obvious over Suzuki in view of Ma.

• Prior Art Relied Upon: Suzuki (Japanese Patent Application Publication No. 2007-277631) and Ma (a 2008 article in Synthetic Metals).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued Suzuki discloses all elements of independent claim 1 except for the specific n-dopant in the ETL. Suzuki teaches a complete OLED device with an encapsulated organic layer sequence, an iridium-containing emission layer, and an ETL described as "high n nature doped." Ma discloses the benefits of using 8-hydroxyquinolinolato-lithium ("Liq") as an n-dopant in an ETL to improve OLED efficiency, current density, and driving voltage. For dependent claims, Suzuki teaches insulation layers of silicon oxide (claim 2), p-doped hole transport layers (claim 4), and color filters (claim 5).
  • Motivation to Combine: A person of ordinary skill in the art (POSITA) would combine Suzuki and Ma to improve the performance of Suzuki’s OLED. Suzuki expressly teaches using a "high n nature doped" ETL and cites references disclosing n-doped ETLs for their known benefits. Ma explicitly teaches that n-doping an ETL with Liq enhances device performance by improving electron injection and transport conductivity. A POSITA would have been motivated to apply Ma's specific, advantageous Liq dopant to Suzuki's general teaching of an n-doped ETL to achieve these predictable benefits.
  • Expectation of Success: A POSITA would have a reasonable expectation of success. N-doped ETLs were widely used in OLEDs, and Liq was a known, art-recognized n-dopant. Combining the teachings would involve applying a known technique (Liq-doping) to a known device structure (Suzuki's OLED) to achieve a predictable improvement, which is a routine modification.

Ground 2: Obviousness over Diekmann and Ma - Claims 1-2, 4-5, 8-10 are obvious over Diekmann in view of Ma.

• Prior Art Relied Upon: Diekmann (International Publication No. WO 2008/040323) and Ma.
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner asserted Diekmann, like Suzuki, discloses a complete OLED device with all elements of the independent claims except the specific Liq n-dopant. Diekmann teaches an OLED with an encapsulated organic stack, an iridium-containing emission layer (Ir(ppy)3), and an explicitly disclosed n-doped ETL. The argument for combining with Ma is analogous to Ground 1: Ma supplies the teaching of using Liq as the specific n-dopant. Diekmann further discloses insulation layers of silicon oxide/nitride (claim 2) and a p-doped hole transport layer (claim 4).
  • Motivation to Combine: The motivation is parallel to that in Ground 1. Diekmann discloses an n-doped ETL to increase conductivity and improve electron injection. A POSITA would have been motivated to use the specific Liq dopant taught by Ma to further enhance the performance of Diekmann’s device, recognizing Liq as an advantageous and more stable dopant compared to those disclosed in Diekmann (e.g., cesium, lithium fluoride).
  • Expectation of Success: A POSITA would have reasonably expected success because Diekmann already teaches an n-doped ETL, and substituting one known n-dopant (from Diekmann) with another known, improved n-dopant (from Ma) was a routine optimization for a skilled artisan.

Ground 3: Obviousness over Suzuki, Ma, and Lee - Claims 3, 11-12, and 15-16 are obvious over Suzuki and Ma in view of Lee.

• Prior Art Relied Upon: Suzuki, Ma, and Lee (Application # 2005/0146267).

• Core Argument for this Ground:

  • Prior Art Mapping: This ground builds on the combination of Suzuki and Ma by adding Lee to render obvious claims related to a specific multi-layer encapsulation structure. Claims 3, 11, and 16 require an encapsulation with first and second layers having distinct, independent "volume structures," where one layer has a higher amorphicity. Lee teaches a multi-layer encapsulation for OLEDs using polymer layers with different levels of crystallinity (e.g., "highly crystalline" and "semi-crystalline") to improve device lifetime by preventing defect propagation and blocking moisture.
  • Motivation to Combine: A POSITA would have been motivated to incorporate Lee’s advanced, multi-layer encapsulation into the OLED of Suzuki/Ma to improve device longevity and reliability. Lee explicitly teaches its encapsulation improves upon conventional encapsulation techniques by providing a lower water vapor transport rate. A POSITA would apply Lee's teachings to improve the sealing of the Suzuki/Ma device, a known area of concern for OLEDs.
  • Expectation of Success: Success would be reasonably expected because applying multi-layer encapsulation techniques was a well-known strategy for improving OLED durability. Lee's method was an incremental improvement over existing encapsulation structures (like Suzuki's), and integrating it would have been a predictable design choice.

• Additional Grounds: Petitioner asserted additional obviousness challenges, including grounds based on Suzuki or Diekmann alone for certain claims (anticipation or obviousness), and further combinations involving Suzuki/Diekmann and Lee, or Diekmann, Ma, and Lee. These grounds relied on similar arguments and mappings for the respective prior art references.

4. Key Claim Construction Positions

• “Electromagnetic radiation in a spectral range from infrared radiation to UV radiation”: Petitioner argued this term is broad and encompasses the "white light" disclosed in the Suzuki and Diekmann references, regardless of whether the construction requires the full spectrum or merely light with wavelengths falling somewhere within that range.
• “Volume structure”: Petitioner argued this term, based on prosecution history, refers to the internal atomic or molecular arrangement of a solid, distinct from its surface structure. Lee's disclosure of encapsulation layers with different levels of crystallinity (e.g., semi-crystalline vs. highly crystalline) was argued to meet the claim limitations requiring layers with respective, independent volume structures and different levels of amorphicity.

5. Relief Requested

• Petitioner requests institution of an inter partes review and cancellation of claims 1-16 of the ’250 patent as unpatentable.