PTAB

IPR2015-00424

CeramTec GmbH v. CeraMedic LLC

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1. Case Identification

2. Patent Overview

  • Title: Sintered Al₂O₃ Material, Process for its Production and Use of the Material
  • Brief Description: The ’584 patent relates to sintered alumina (Al₂O₃) ceramic materials for use in applications like medical implants. The invention is defined by a specific combination of physical and mechanical properties, including high density, small mean grain size, high Vickers hardness, high flexural strength, and a low value for a parameter termed "dimensionless defect density" (DDD).

3. Grounds for Unpatentability

Ground 1: Claims 14 and 26-29 are anticipated under 35 U.S.C. §102 or obvious under §103 over Igarashi.

  • Prior Art Relied Upon: Igarashi (Japanese Application # JP1990255563).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Igarashi’s Example 1 material expressly discloses a sintered alumina body meeting nearly all limitations of independent claims 14 and 26. Specifically, Igarashi was alleged to teach a material with the claimed mean grain size (≤2.0 µm), density (≥98.5% of theoretical), Vickers hardness (≥1,750), and flexural strength (≥800 MPa). The central contention focused on the "dimensionless defect density" (DDD) limitation, which Petitioner asserted was an inventor-created metric not used in the prior art. Petitioner argued this limitation was inherently disclosed by Igarashi. The argument rested on the well-established inverse relationship between a ceramic's flexural strength and its microstructural defect level, which DDD purports to quantify. Because Igarashi’s material exhibited a substantially higher flexural strength (1066 MPa) than the materials described in the ’584 patent’s own examples, Petitioner contended it must necessarily possess a lower level of defects, resulting in a DDD value that falls within the claimed range.
    • Motivation to Combine (for §103 grounds): As an alternative to inherency, Petitioner argued that achieving the claimed DDD would have been obvious. A person of ordinary skill in the art (POSITA) starting with Igarashi’s high-strength material would be motivated to optimize its properties by reducing microstructural defects, a known result-effective variable for improving strength. The DDD parameter merely applied a new label to this known variable.
    • Expectation of Success (for §103 grounds): A POSITA would have a high expectation of success because the relationship between minimizing defects and increasing strength in sintered alumina was a predictable and fundamental principle in ceramics science.

Ground 2: Claims 14 and 26-29 are anticipated under §102 or obvious under §103 over Hayashi.

  • Prior Art Relied Upon: Hayashi (Patent 4,952,537).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner asserted a parallel argument that Hayashi’s "P8" material anticipates or renders obvious the challenged claims. Hayashi was alleged to disclose a sintered alumina material meeting the claimed density (≥99.9%) and mean grain size (<1.5 µm). Petitioner argued that Hayashi's reported flexural strength of 82 kg/mm² (804 MPa) met the claim requirement of ≥800 MPa. While Hayashi reported a Vickers hardness >2,020 without specifying the test load, Petitioner argued the hardness limitation was inherently met because the P8 material's superior density and smaller grain size compared to examples in the ’584 patent would necessarily result in higher hardness. As with Igarashi, the DDD limitation was argued to be inherently disclosed due to the material's high flexural strength, which is indicative of a low defect level.
    • Motivation to Combine (for §103 grounds): If not inherently disclosed, a POSITA would find it obvious to start with Hayashi's high-quality material and apply routine optimization techniques to minimize defects to achieve the claimed DDD, as defect reduction was a known pathway to enhance strength.
    • Expectation of Success (for §103 grounds): Success in achieving a low-defect, high-strength material was expected based on the well-understood principles taught in Hayashi and the general knowledge in the art regarding ceramic processing.
    • Key Aspects: Petitioner highlighted that Hayashi was overcome during prosecution based on the patentee’s allegedly flawed arguments that Hayashi failed to disclose the test load for hardness and did not meet the strength limitation. Petitioner contended that a correct interpretation of material science principles and a simple unit conversion for strength demonstrate that Hayashi does, in fact, teach these limitations.

4. Key Claim Construction Positions

  • "at a test load from 10 to 100 N": Petitioner argued this term should be construed to mean the required Vickers hardness value must be achieved at any single test load within the specified range, not necessarily across the entire range. This construction was supported by the claim's use of "a" test load and examples in the specification where hardness was measured at a single point.
  • "dimensionless defect density" (DDD): Petitioner adopted the patent’s explicit definition—"the sum of the squares of the defect sizes per area analysed." The core of Petitioner's argument was that this is an inventor-created parameter that quantifies a long-understood material property (defect structure) and does not represent a patentable distinction over prior art materials that inherently possessed the claimed property.

5. Relief Requested

  • Petitioner requested the institution of an inter partes review and the cancellation of claims 14 and 26-29 of Patent 6,066,584 as unpatentable.