Sony Corp v. Fujifilm Corp

1. Case Identification

• Case #: IPR2017-00618
• Patent #: 7,355,805
• Filed: January 6, 2017
• Petitioner(s): Sony Corporation
• Patent Owner(s): Fujifilm Corporation
• Challenged Claims: 1-3 and 10

2. Patent Overview

• Title: Encoding Data into Timing-Based Servo Patterns on Magnetic Tape
• Brief Description: The ’805 patent discloses a magnetic tape with timing-based servo patterns where data for identifying a specific servo band is embedded directly into that band’s servo signal. This technique allows a read head to determine its position on a specific band without needing to reference or compare signals from adjacent servo bands.

3. Grounds for Unpatentability

Ground 1: Claims 1-3 and 10 are Anticipated by Hennecken

• Prior Art Relied Upon: Hennecken (Patent 6,710,967).
• Core Argument for this Ground: Petitioner argued that the "Background Art" section of Hennecken, which describes technology known prior to its own invention, inherently discloses every limitation of the challenged claims.
  • Prior Art Mapping: Hennecken’s background section described a known technique of encoding a unique "servo stripe number" into the timing-based servo pattern of each servo track. This was achieved by varying the spacing between low-frequency transitions. Petitioner asserted that encoding this unique identifier on each track inherently enables a read head to determine its coarse transverse location by reading the data from a single track, thus meeting the key limitation of claim 1. The use of non-parallel stripes (claim 2) and the implicit disclosure of the conventional method for writing such encoded patterns (claims 3 and 10) were also allegedly disclosed.

Ground 2: Claims 1-3 and 10 are obvious over Hennecken in view of Albrecht II

• Prior Art Relied Upon: Hennecken (Patent 6,710,967) and Albrecht II (Patent 5,930,065).
• Core Argument for this Ground: Petitioner argued that even if Hennecken’s background does not anticipate, it renders the claims obvious when combined with Albrecht II. Albrecht II provides a known multi-channel servo writer system capable of writing different data to different servo tracks, which is the exact technology needed to implement the servo identification scheme described in Hennecken.
  • Prior Art Mapping: Hennecken’s background taught the concept of encoding a unique number on each servo track. Albrecht II taught a specific apparatus and method for achieving this, disclosing a multi-channel servo writer with separate pulse generators to write different, distinct data streams onto multiple servo tracks simultaneously.
  • Motivation to Combine: A POSITA would combine these references because Hennecken explicitly noted that writing different data to each track (as required for unique servo numbers) could not be accomplished with a single current driver. This statement would have directly motivated a POSITA to seek a known multi-channel servo writer solution, such as the one described in Albrecht II. Further, Albrecht II was purported to address other known drawbacks mentioned in Hennecken, such as improving information transfer rates and remedying asymmetric spacing.
  • Expectation of Success: A POSITA would have a high expectation of success, as the combination involved using a known type of servo writer (Albrecht II) to implement a known encoding scheme (Hennecken) to achieve the predictable result of a tape with self-identifying servo tracks.

Ground 3: Claims 1-3 and 10 are obvious over Hennecken in view of Albrecht II and Dugas

• Prior Art Relied Upon: Hennecken (Patent 6,710,967), Albrecht II (Patent 5,930,065), and Dugas (Patent 6,496,328).

• Core Argument for this Ground: Petitioner asserted that adding Dugas to the combination of Hennecken and Albrecht II makes the obviousness case even stronger. Dugas provided a specific, improved, and commercially relevant implementation of the multi-channel servo writer concept, particularly one with a five-channel head that matched the predominant industry standard (LTO).

  • Prior Art Mapping: This combination leveraged the encoding concept from Hennecken, the general writing technique from Albrecht II, and the specific, efficient five-channel magnetic recording head taught by Dugas. This combination taught writing unique servo track numbers onto five separate servo tracks simultaneously.
  • Motivation to Combine: A POSITA, having identified the need for a multi-channel writer from Hennecken and Albrecht II, would have been motivated to use the specific five-channel head from Dugas. This was because the five-servo-track layout was the predominant industry standard at the time (e.g., the LTO standard), making the Dugas head a logical choice for creating a compliant and commercially relevant product. Dugas also explicitly described its head as a remedy for drawbacks in earlier servo writers, providing additional motivation for its adoption.
  • Expectation of Success: Success would be highly expected, as this ground proposed integrating known components (Hennecken's encoding, Albrecht II's method, Dugas's hardware) for their intended and well-understood purposes.

• Additional Grounds: Petitioner asserted an additional obviousness challenge to claims 1-3 and 10 over Albrecht II in view of Hennecken but relied on similar arguments.

4. Key Claim Construction Positions

• "wherein reading the data enables a servo read head... to specify on which servo band the servo read is currently positioned without referring to other servo bands" (Claim 1): Petitioner argued that under the broadest reasonable interpretation, this limitation is met by any difference in the data encoded on respective servo bands that allows for unique identification. The data does not need to have been encoded for the sole purpose of band identification.
• "a plurality continuous patterns sets each of which pattern is nonparallel stripes" (Claim 2): Petitioner contended this phrase corresponds to a "servo burst" or "sub-frame" as understood in the art of conventional timing-based servo patterns. Therefore, the phrase simply means two or more groups (or bursts) of non-parallel stripes.

5. Relief Requested

• Petitioner requests institution of IPR and cancellation of claims 1-3 and 10 as unpatentable.