Fujifilm Corp v. Sony Corp

1. Case Identification

• Case #: IPR2017-01389
• Patent #: 6,896,959
• Filed: May 8, 2017
• Petitioner(s): Fujifilm Corporation
• Patent Owner(s): Sony Corporation
• Challenged Claims: 1-18

2. Patent Overview

• Title: Dual-Layer Magnetic Recording Medium
• Brief Description: The ’959 patent discloses a dual-layer magnetic recording medium designed to achieve high-density recording. The invention focuses on the specific physical and magnetic properties of metallic particle pigments within the upper magnetic layer, such as high coercivity, small particle size, and high volume concentration, to produce a narrow pulse width (PW50).

3. Grounds for Unpatentability

Ground 1: Inherent Anticipation by Mori - Claims 1-9 and 11-16 are anticipated under 35 U.S.C. §102 by Mori.

• Prior Art Relied Upon: Mori (Japanese Application Publication # JP2002-074641).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Mori, which discloses a dual-layer magnetic recording medium for high-density recording, inherently discloses every limitation of the challenged claims. Petitioner asserted that Mori’s examples teach a magnetic upper layer with a primary magnetic metallic particulate pigment. Based on Mori’s disclosed material recipe, Petitioner calculated the volume concentration to be over 35% (e.g., 39.5% to 59.5%), the coercivity to be over 2000 Oe (e.g., 2400 Oe), and the average particle length to be under 100 nm (e.g., 70 nm).
  • Key Aspects: A central part of the argument was that the claimed orientation ratio and PW50 values, while not explicitly stated in Mori, were inherently disclosed. Petitioner contended that a person of ordinary skill in the art (POSA) would understand that Mori’s disclosed squareness value (≥0.85) necessarily results in an orientation ratio greater than 2.0 based on known linear relationships in the art. Furthermore, Petitioner argued the claimed PW50 value (<500 nm) is inherent in Mori’s examples by applying a linear regression formula derived from the ’959 patent’s own experimental data to the remanence-thickness (Mr*t) and coercivity (Hc) values disclosed in Mori.

Ground 2: Inherent Anticipation by Sasaki - Claims 1-9 and 11-18 are anticipated under §102 by Sasaki.

• Prior Art Relied Upon: Sasaki (Japanese Application Publication # JP2000-40217).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner alleged that Sasaki’s examples 1, 2, and 5 anticipate the challenged claims. Sasaki discloses a multilayered coated magnetic recording medium with an upper magnetic layer containing ferromagnetic metal powders. Petitioner’s calculations based on Sasaki’s recipe showed a volume concentration of 39.7%, meeting the "at least about 35%" limitation. Sasaki explicitly discloses coercivity values (e.g., 2400 Oe), particle sizes (e.g., 60-85 nm), and remanence-thickness products (e.g., 2.94-3.02 memu/cm²) that fall within the claimed ranges.
  • Key Aspects: Similar to the Mori argument, Petitioner asserted that the orientation ratio and PW50 were inherently disclosed. A POSA would recognize that Sasaki’s disclosed squareness of ~0.9 translates to an orientation ratio of 2.4 or higher. Using the same linear regression analysis derived from the ’959 patent, Petitioner calculated the inherent PW50 for Sasaki’s examples to be well below the claimed 500 nm threshold (e.g., 270-441 nm).

Ground 3: Obviousness over Aonuma and Mori - Claims 1-18 are obvious over Aonuma in view of Mori.

• Prior Art Relied Upon: Aonuma (Japanese Application Publication # JP2001-319315) and Mori.

• Core Argument for this Ground:

  • Prior Art Mapping: Petitioner argued that Aonuma discloses nearly all limitations of the challenged claims, including a dual-layer medium with specific values for PW50, orientation ratio, and particle size. To the extent Aonuma’s preferred coercivity (up to 1948 Oe) falls just short of the claimed "at least about 2000 Oe," Petitioner contended it would have been obvious to modify Aonuma’s formulation using the higher-coercivity ferromagnetic powder taught by Mori (≥2100 Oe).
  • Motivation to Combine: A POSA would combine Mori’s teaching of higher coercivity with Aonuma’s system to achieve the well-known benefit of decreased PW50 and greater recording density, a shared goal of both references. Mori’s disclosure of a thinner magnetic layer would have resolved any potential concerns a POSA might have had from Aonuma about recording head heating associated with higher coercivity powders.
  • Expectation of Success: The combination involved substituting a known type of magnetic particle for another to optimize a predictable property (recording density), a routine practice in the field of magnetic media development.

• Additional Grounds: Petitioner asserted additional challenges, including that claims 1-2 and 4-18 are anticipated by Aonuma alone, and that various claims are obvious over combinations of Mori or Sasaki with Mee (a textbook) and Tokuoka (a patent disclosing relationships between squareness and orientation ratio).

4. Key Claim Construction Positions

• "volume concentration": Petitioner proposed this term should be construed as "the volume of the primary magnetic metallic particulate pigment divided by the volume of all materials that form the magnetic layer," as calculated from the recipe of materials used.
• "magnetic metallic particulate pigment": Petitioner argued this term includes metal and/or metal alloy particles but explicitly excludes hexagonal ferrites, which the patent specification describes as a distinct, alternative embodiment.
• "orientation ratio": Petitioner adopted the patent’s explicit definition, simplified to mean the ratio of the saturation remanence measured in the intended transport direction to that measured in the perpendicular in-plane direction.

5. Key Technical Contentions (Beyond Claim Construction)

• Inherent Disclosure of PW50: A critical technical contention was that the claimed PW50 value was an inherent property of the prior art media when measured on appropriate equipment. Petitioner established a linear relationship between PW50 and the square root of (Mrt/Hc) by performing a linear regression on the experimental data provided in Table 2 of the challenged ’959 patent itself. Petitioner then used this derived formula to calculate the PW50 values for the Mori and Sasaki examples based on their disclosed Mrt and Hc values, demonstrating that these prior art media would necessarily have exhibited a PW50 within the claimed range.

6. Relief Requested

• Petitioner requested the institution of an inter partes review (IPR) and cancellation of claims 1-18 of the ’959 patent as unpatentable.