PTAB

IPR2021-00185

Samsung Electronics Co Ltd v. Nanoco Technologies Ltd

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Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Nanoparticles
  • Brief Description: The ’557 is directed to a method of producing multi-shell semiconductor nanoparticles, such as quantum dots (QDs), with a core/shell/shell structure. The method comprises forming a nanoparticle core by effecting conversion of a core precursor composition—which includes a first precursor species and a separate second precursor species—in the presence of a "molecular cluster compound" (MCC) that is different from the precursors and acts as a seed for nanoparticle growth.

3. Grounds for Unpatentability

Ground 1: Claims 1-6 and 16-17 are obvious over Banin in view of Braun.

  • Prior Art Relied Upon: Banin (WO 03/097904) and Braun (J. Phys. Chem. A, 2001).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Banin discloses the core inventive concept: synthesizing semiconductor nanocrystals (e.g., InAs) by reacting at least two different precursors (e.g., In-based and As-based) in the presence of a separate metal catalyst, such as a gold (Au) MCC, which acts as a seed for nanorod growth. Banin further teaches that adding shell layers can improve the nanocrystals' optical properties. Braun discloses the synthesis of multi-shell nanoparticles with a specific quantum dot quantum well (QDQW) structure (e.g., CdS/HgS/CdS) to achieve enhanced quantum confinement and improved optical characteristics. The combination of Banin's seeded, two-precursor synthesis method with Braun's well-known multi-shell QDQW structure would result in the method claimed in the ’557 patent.
    • Motivation to Combine: A person of ordinary skill in the art (POSITA) would have been motivated to apply the advanced multi-shell structures taught by Braun to the seeded-growth synthesis method of Banin. The explicit goal was to improve the optical and electrical properties of the resulting nanoparticles, a well-understood benefit of creating QDQW structures.
    • Expectation of Success: A POSITA would have had a reasonable expectation of success because Banin and Braun operate in the same field of art (nanoparticle synthesis) and teach similar solution-based synthesis techniques. Banin specifically identifies materials like CdS and HgS, which are the very materials used in Braun's exemplary QDQW structures.

Ground 2: Claims 1 and 16-17 are obvious over Zaban in view of Ptatschek and Braun.

  • Prior Art Relied Upon: Zaban (Langmuir, 1998), Ptatschek (Berichte der Bunsen-Gesellschaft für Physikalische Chemie, 1998), and Braun (J. Phys. Chem. A, 2001).
  • Core Argument for this Ground:
    • Prior Art Mapping: Zaban discloses synthesizing InP QDs by reacting two precursors (In-based and P-based) in the presence of a third, simple Zn-based precursor (zinc acetate). Ptatschek discloses using a specific Zn-based MCC as a single-source precursor that forms highly reactive "seeds" to nucleate QD synthesis. Petitioner argued a POSITA would replace Zaban's simple zinc acetate with Ptatschek's more sophisticated Zn-based MCC to gain the known advantages of MCC-seeded growth. Braun is again relied upon for its teaching of multi-shell QDQW structures.
    • Motivation to Combine: A POSITA would combine Zaban and Ptatschek to improve synthesis efficiency, as MCCs were known to allow for faster reactions at lower temperatures and produce more uniform nanoparticles. The motivation to then incorporate Braun's teachings is, as in Ground 1, to further enhance the optical properties of the resulting nanoparticles by creating an advanced multi-shell structure.
    • Expectation of Success: A POSITA would have expected success in substituting Ptatschek's MCC into Zaban's method because the prior art was replete with examples of using MCCs for seeded growth from separate precursors. Furthermore, the zinc sources in Zaban and Ptatschek were chemically similar. Creating the multi-shell structure would also be predictable, as Braun demonstrates its formation using similar solution-based chemistry.

Ground 3: Claims 1, 4, and 16-17 are obvious over Lucey in view of Ahrenkiel and Braun.

  • Prior Art Relied Upon: Lucey (Patent 7,193,098), Ahrenkiel (Nano Letters, 2003), and Braun (J. Phys. Chem. A, 2001).

  • Core Argument for this Ground:

    • Prior Art Mapping: Lucey teaches a process for producing nanoparticles by reacting a metal-ligand complex (an MCC) with a single precursor. Ahrenkiel, in contrast, teaches that using a mixture of two different precursors to synthesize InP nanorods provides superior control over the final product's dimensions (e.g., length) and optical properties. Petitioner argued it would have been obvious to modify Lucey's MCC-based method by replacing its single precursor with Ahrenkiel's two-precursor system. Braun provides the final piece by teaching the specific multi-shell QDQW structure.
    • Motivation to Combine: A POSITA would have been motivated to replace Lucey's single precursor with Ahrenkiel's two-precursor approach to maximize the optical efficiency of the resulting nanoparticles by better controlling their size and shape, as explicitly taught by Ahrenkiel.
    • Expectation of Success: The combination was a predictable optimization, as both Lucey and Ahrenkiel teach methods for synthesizing InP nanoparticles. Ahrenkiel's successful use of multiple precursors to create similar nanoparticles would have given a POSITA a high degree of confidence that incorporating this technique into Lucey's MCC-based system would be successful.

  • Additional Grounds: Petitioner asserted an additional obviousness challenge to claims 4-6 based on Zaban, Ptatschek, Braun, and Yu, arguing Yu’s disclosure of low-temperature synthesis would have motivated a POSITA to modify the reaction conditions to achieve more uniform nanoparticles with lower energy input.

4. Key Claim Construction Positions

  • Petitioner argued that the term "molecular cluster compound" did not require formal construction. However, it noted that two related patents assigned to the Patent Owner provide slightly different definitions. Petitioner contended that the term was widely understood in the art and that the compounds disclosed in the prior art references (e.g., the gold clusters in Banin and the zinc clusters in Ptatschek) would qualify as MCCs under any reasonable interpretation.

5. Arguments Regarding Discretionary Denial

  • Petitioner argued that discretionary denial under §314(a) based on Fintiv factors would be inappropriate. The core arguments were:
    • The parallel district court litigation was in its early stages, with significant work remaining before trial.
    • Petitioner had stipulated that, if IPR is instituted, it will not pursue in the district court the same grounds or grounds based on the same primary references.
    • The petition presents a reasonably strong case for unpatentability.
    • These factors, taken together, weigh against exercising discretion to deny institution, as proceeding with the IPR would serve the interests of efficiency and the integrity of the patent system.

6. Relief Requested

  • Petitioner requests institution of inter partes review and cancellation of claims 1-6 and 16-17 of the ’557 patent as unpatentable.