PTAB

IPR2017-00618

Sony Corporation v. FUJIFILM Corporation

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1. Case Identification

2. Patent Overview

  • Title: Magnetic Tape with Encoded Servo Band Identification
  • Brief Description: The `’805 patent` is directed to a magnetic tape storage system where timing-based servo patterns include encoded data that identifies the specific servo band being read. This technology purports to allow a tape drive to determine its position without needing to reference or compare signals from adjacent servo bands.

3. Grounds for Unpatentability

Ground 1: Anticipation of Claims 1-3 and 10 by Hennecken

  • Prior Art Relied Upon: Hennecken (Patent 6,710,967).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that the "Background Art" section of Hennecken explicitly describes the invention claimed in the `’805 patent`. Hennecken teaches that a "servo stripe number" can be encoded into the timing-based servo pattern of each track for "coarse transverse location." Petitioner asserted this encoded number inherently enables a read head to identify the specific servo track it is on, thus meeting the key limitation of claim 1 to specify a servo band without referring to others. The method of encoding by varying the spacing between transitions, as described in Hennecken, was argued to anticipate the limitations of dependent claims 2, 3, and 10.
    • Key Aspects: Petitioner contended that this clear disclosure in Hennecken's "Background Art" section was overlooked by the examiner during the original prosecution of the `’805 patent`.

Ground 2: Obviousness of Claims 1-3 and 10 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:
    • Prior Art Mapping: Hennecken provides the foundational teaching of encoding a unique servo track number onto each servo band. Albrecht II discloses the necessary enabling technology: a multi-channel servo writer with separate pulse generators capable of writing different data patterns to different servo tracks simultaneously. The combination of Hennecken's concept with Albrecht II's implementation renders the claims obvious.
    • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA) would be motivated to combine these references for several reasons. First, Hennecken explicitly states that writing different patterns to each track requires more than a single current driver, directly pointing a POSITA towards a known multi-channel writer solution like that disclosed in Albrecht II. Second, Albrecht II was designed to solve other known issues with timing-based servo encoding that Hennecken also mentioned, such as improving data transfer rates and remedying asymmetric encoding, providing further motivation for its use.
    • 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 concept (Hennecken) to achieve the predictable result of a magnetic tape with uniquely identifiable servo bands.

Ground 3: Obviousness of Claims 1-3 and 10 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:

    • Prior Art Mapping: This ground builds upon the previous one by adding Dugas, which discloses a specific, improved multi-channel recording head. Hennecken provides the concept, Albrecht II provides the general multi-channel writing technique, and Dugas provides the specific, state-of-the-art hardware for its implementation. Dugas discloses a five-channel recording head, which corresponds to the five-band system described in the `’805 patent` and the predominant LTO industry standard layout at the time.
    • Motivation to Combine: A POSITA seeking to implement the system of Hennecken and Albrecht II would be motivated to use the multi-channel head of Dugas for two primary reasons. First, it would allow the final product to be compliant with the prevalent five-band LTO standard. Second, Dugas explicitly describes its head as an improvement that remedies drawbacks of earlier designs (like that in Albrecht II), offering a more efficient and higher-performing solution.
    • Expectation of Success: Combining these elements would be a straightforward application of known technologies to create an industry-standard-compliant and efficient system, leading to a high expectation of success.

  • Additional Grounds: Petitioner asserted an additional obviousness challenge based on Albrecht II in view of Hennecken (Ground 4), relying on similar design rationales for combining the references to encode servo track numbers for coarse transverse location.

4. Key Claim Construction Positions

  • "wherein reading the data enables a servo read head...to specify on which servo band...without referring to other servo bands."
    • Petitioner argued that under the broadest reasonable interpretation, this limitation is met by any difference in the data encoded in the respective servo bands that allows a read head to identify a band, regardless of whether the data was encoded for that specific purpose. This broad construction makes the limitation easier to find in prior art that encodes other data, like manufacturer information, which would necessarily be different across tracks.
  • "a plurality continuous patterns sets each of which pattern is nonparallel stripes"
    • Petitioner argued this term corresponds to the conventional "sub-frames" or "bursts" that are the fundamental building blocks of well-known, timing-based servo patterns. By equating this claim language to a standard, known feature, Petitioner contended it was not a point of novelty and was readily taught by the prior art.

5. Relief Requested

  • Petitioner requests the institution of an inter partes review and the cancellation of claims 1-3 and 10 of Patent 7,355,805 as unpatentable.