FUJIFILM Corporation v. Sony Corporation

1. Case Identification

• 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: Magnetic Recording Medium
• Brief Description: The ’959 patent is directed to a dual-layer magnetic recording medium designed to achieve high-density recording. The alleged invention involves using a magnetic upper layer containing specific metallic particle pigments with defined properties—such as high coercivity, small particle size, and high volume concentration—to yield significantly improved pulse width (PW50) characteristics.

3. Grounds for Unpatentability

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

• Prior Art Relied Upon: Mori (Certified Translation of Japanese Unexamined Patent Application Publication # JP2002-074641).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Mori, which describes a dual-layer magnetic recording medium, inherently discloses every limitation of the challenged claims. Mori explicitly teaches a dual-layer structure with a non-magnetic lower layer and a magnetic upper layer. Petitioner contended that Mori’s disclosure of using an "acicular" ferromagnetic alloy powder with a specified recipe, when analyzed, meets the claimed limitations for coercivity (>2000 Oe), volume concentration (>35%), and average particle length (<100 nm).
  • Key Aspects: A central part of the argument was that Mori inherently discloses the claimed PW50 and orientation ratio values. Petitioner asserted that a person of ordinary skill in the art (POSA) could calculate the remanence-thickness product (Mr*t) from Mori's disclosed parameters, finding it falls within the claimed range (<5.0 memu/cm²). Furthermore, Petitioner argued that the claimed PW50 value is inherently met by using a linear regression model derived from the ’959 patent’s own test data and applying it to the physical properties disclosed in Mori's examples. Similarly, the orientation ratio was argued to be inherently disclosed based on Mori's teachings of squareness and the known relationship between squareness and orientation ratio established in other prior art (Tokuoka).

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

• Prior Art Relied Upon: Sasaki (Certified Translation of Japanese Unexamined Patent Application Publication # JP2000-040217).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner asserted that Sasaki, like Mori, discloses a dual-layer magnetic recording medium that anticipates the challenged claims. Sasaki teaches a multilayered medium with an upper magnetic layer containing iron-based ferromagnetic metal powders. Petitioner’s calculations, based on Sasaki’s disclosed recipe, allegedly demonstrated a volume concentration of 39.7%, meeting the "at least about 35%" limitation of claim 1. Sasaki’s examples were also shown to meet the claimed coercivity (>2000 Oe), particle size (<100 nm), and Mr*t (<5.0 memu/cm²) values.
  • Key Aspects: As with the Mori anticipation argument, Petitioner contended that the PW50 value was inherent in Sasaki. By applying the same linear regression analysis derived from the ’959 patent’s data to the properties of Sasaki's examples, Petitioner calculated PW50 values that were all below the claimed 500 nm threshold. The orientation ratio was also argued to be inherently disclosed based on Sasaki's high squareness values (around 0.9) and the established formula in Tokuoka, resulting in a ratio greater than 2.0.

Ground 3: Claims 1-18 are obvious under §103 over Aonuma in view of Mori

• Prior Art Relied Upon: Aonuma (Certified Translation of Japanese Unexamined Patent Application Publication # JP2001-319315), Mori.

• Core Argument for this Ground:

  • Prior Art Mapping: Petitioner argued that to the extent Aonuma does not anticipate every limitation, the claims would have been obvious over Aonuma in view of Mori. Aonuma discloses a dual-layer magnetic medium with most of the claimed features but teaches a preferred coercivity range topping out at 1948 Oe, just below the claimed "about 2000 Oe." Mori explicitly teaches using higher coercivity powders (≥2100 Oe) to achieve the same goal of higher recording density.
  • Motivation to Combine: A POSA would combine Aonuma with Mori to improve recording density. Aonuma discloses that a low PW50 value permits greater recording density, a well-known benefit. Given the known relationship between higher coercivity (Hc) and lower PW50, a POSA would have been motivated to substitute the higher Hc powder taught by Mori into Aonuma’s medium to achieve this known benefit.
  • Expectation of Success: A POSA would have had a reasonable expectation of success in making this combination, as both references relate to improving performance in magnetic tape and Mori explicitly teaches that higher coercivity maintains stable recording.

• Additional Grounds: Petitioner asserted additional challenges, including anticipation of various claims by Aonuma alone (Ground 3) and obviousness challenges combining Sasaki with Aonuma (Ground 8). Further obviousness grounds relied on Mori or Sasaki in view of Mee (a textbook) and Tokuoka (a patent) to the extent the Board found that the PW50 and orientation ratio values were not inherently disclosed. These arguments asserted it would have been obvious to apply the well-known principles from Mee and Tokuoka to the media of Mori or Sasaki.

4. Key Claim Construction Positions

• "volume concentration": Petitioner argued this term was not explicitly defined in the patent. Based on extrinsic evidence, Petitioner proposed it 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," calculated from the recipe of materials.
• "magnetic metallic particulate pigment": Petitioner contended that the specification and extrinsic evidence support a construction that includes metal and/or metal alloys but excludes hexagonal ferrites, which are described as a separate, alternative embodiment in the ’959 patent.
• "orientation ratio": The patent provides a definition, which Petitioner simplified to "[t]he ratio of the saturation remanence measured in the recording medium's intended transport direction to the saturation remanence measured in the in-plane direction perpendicular to the recording medium's intended transport." This construction was foundational to calculating the ratio from prior art squareness values.

5. Key Technical Contentions (Beyond Claim Construction)

• Inherent Disclosure of PW50 via Linear Regression: A critical technical argument underpinning multiple grounds was that the claimed PW50 values were an inherent, unstated property of the prior art media. Petitioner established a linear relationship between PW50 and the square root of (Mr*t/Hc) by performing a linear regression on the experimental data provided in the ’959 patent itself. Petitioner then used this derived formula to calculate the PW50 values for the media described in Mori and Sasaki, arguing that they would necessarily exhibit the claimed PW50 performance when used in a standard drive.

6. Relief Requested

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