Intellectual Ventures II LLC v. Mitsuba Corp

I. Executive Summary and Procedural Information

• Parties & Counsel:
  • Plaintiff: Intellectual Ventures II LLC (Delaware)
  • Defendant: Mitsuba Corporation (Japan) and American Mitsuba Corporation (Michigan)
  • Plaintiff’s Counsel: Farnan LLP
• Case Identification: 1:17-cv-00298, D. Del., 03/20/2017
• Venue Allegations: Plaintiff alleges venue is proper in the District of Delaware based on Defendants maintaining a regular place of business, committing alleged acts of infringement, and deriving substantial revenue from the district.
• Core Dispute: Plaintiff alleges that certain electronic power steering units manufactured and sold by Defendants infringe a patent related to the assembly of electric motor stators.
• Technical Context: The lawsuit concerns methods for manufacturing electric motor stators, specifically techniques for arranging and securing wound wire segments to improve manufacturing efficiency and motor performance.
• Key Procedural History: The complaint was filed on March 20, 2017. Subsequent to this filing, the patent-in-suit was the subject of multiple Inter Partes Review (IPR) proceedings before the U.S. Patent and Trademark Office. Following these proceedings, the patent owner filed a disclaimer for claims 1-6 and 8-14 of the patent, which includes both claims asserted in this litigation (claims 10 and 12). This disclaimer is noted in the patent's IPR certificate and subsequent official gazette notices.

Case Timeline

Date	Event
2001-03-02	Priority Date for U.S. Patent No. 7,067,952
2006-06-27	U.S. Patent No. 7,067,952 Issued
2017-03-20	Complaint Filed
2019-09-27	Inter Partes Review Certificate Issued, noting disclaimed claims

II. Technology and Patent(s)-in-Suit Analysis

• Patent Identification: U.S. Patent No. 7,067,952, "Stator assembly made from a molded web of core segments and motor using same," issued June 27, 2006.
• The Invention Explained:
  • Problem Addressed: The patent describes several drawbacks with conventional methods of making electric motor stators. These include inconsistent magnetic properties due to the grain orientation in stamped circular steel pieces, difficulty in tightly winding wires in the cramped space of a stator core, and mechanical tolerance "stack up" issues that reduce motor efficiency (’952 Patent, col. 1:30-2:22).
  • The Patented Solution: The invention proposes a method where discrete, individual "arc segments" of the stator core are first linked together by a "phase change material" (e.g., a thermoplastic) to form a continuous, flexible strip ('952 Patent, col. 4:15-22; Fig. 5). This linear arrangement allows for wire to be wound around the poles of each segment more easily and with a higher packing density. After winding, the strip is rolled into a circular "toroidal core" to form the final stator assembly ('952 Patent, col. 7:6-14; Fig. 7).
  • Technical Importance: This manufacturing approach is presented as a way to create smaller, more powerful motors by enabling higher wire packing density and to improve motor performance by using arc segments with a more uniform steel grain structure ('952 Patent, col. 11:1-8, 11:26-34).
• Key Claims at a Glance:
  • The complaint asserts independent claims 10 and 12 ('952 Patent, col. 14:1-20).
  • Independent Claim 10:
    • a plurality of discrete stator segments each at least partially encased with a phase change material;
    • the phase change material also comprises a bridge between adjacent segments to link them into a continuous strip;
    • the bridge is formed by interconnecting two mating sections formed from the phase change material; and
    • the linked stator segments are arranged and secured together to form the stator assembly.
  • Independent Claim 12:
    • A stator assembly according to claim 10 where the stator segments are held in a toroidal shape by a retaining member.
  • The complaint does not explicitly reserve the right to assert dependent claims.

III. The Accused Instrumentality

• Product Identification: The complaint identifies the accused products as the "Mitsuba electronic power steering unit with Honda part number 53602-TV0-E01, the Mitsuba electronic power steering unit with Honda part number 53281-TG7-A20, and the Mitsuba electronic power steering unit with Honda part number 53602-SZT-G01" (collectively, the "Exemplary Mitsuba Products") (Compl. ¶11).
• Functionality and Market Context: The complaint identifies the accused instrumentalities as components of automotive electronic power steering systems but provides no further detail on their specific technical operation, features, or market position (Compl. ¶11). No probative visual evidence provided in complaint.

IV. Analysis of Infringement Allegations

The complaint's substantive infringement allegations are contained entirely within referenced exhibits (Exhibits 2-4) that were not included with the public filing (Compl. ¶¶13-14, 20). The body of the complaint does not provide a narrative infringement theory or map any specific features of the accused products to the limitations of the asserted claims.

• Identified Points of Contention: Lacking specific infringement contentions in the complaint, any analysis must focus on the questions the plaintiff would need to answer to prove infringement.
  • Technical Questions: A central question would be whether the accused Mitsuba products are manufactured using the specific process recited in the claims. What evidence would show that the stators are assembled from "discrete stator segments" that are first linked into a "continuous strip" via a "bridge" before being formed into a final assembly, as required by claim 10? What component of the accused products allegedly constitutes the "retaining member" of claim 12?

V. Key Claim Terms for Construction

• The Term: "phase change material"

• Context and Importance: This term is foundational to the claimed invention, as it forms the "bridge" linking the discrete segments. Its definition is critical to determining whether the material used in the accused products falls within the scope of the claims.

• Intrinsic Evidence for Interpretation:

  • Evidence for a Broader Interpretation: The specification states that the material can be "temperature activated" (like a thermoplastic) or "chemically activated" (like an epoxy), suggesting a broad definition covering different material types ('952 Patent, col. 6:9-12).
  • Evidence for a Narrower Interpretation: The patent provides very specific physical properties for preferred embodiments, such as a coefficient of linear thermal expansion (CLTE) of less than 2x10⁻⁵ in/in/°F and a thermal conductivity of at least 0.4 watts/meter°K ('952 Patent, col. 8:56-65). A defendant might argue these properties limit the scope of the term to high-performance, thermally-matched polymers.

• The Term: "bridge...formed by interconnecting two mating sections"

• Context and Importance: This limitation in claim 10 describes a specific method for creating the continuous strip of stator segments. Infringement of claim 10 hinges on whether the accused products are made using this particular technique. Practitioners may focus on this term to dispute the manufacturing process.

• Intrinsic Evidence for Interpretation:

  • Evidence for a Broader Interpretation: The term could be argued to cover any method where pre-molded sections of webbing are joined together.
  • Evidence for a Narrower Interpretation: The specification describes a specific process where this is accomplished by "designing the tool to insert a section of the plastic webbing of the outermost segment molded in the prior cycle with the new laminations to be molded," which then "mechanically lock with or, depending upon design, re-melt, the webbing from the prior cycle" ('952 Patent, col. 6:38-44). This detailed description could be used to argue for a narrower construction limited to this specific injection molding technique.

VI. Other Allegations

• Willful Infringement: The complaint does not contain an explicit allegation of willful infringement. It includes a prayer for a finding that the case is "exceptional" under 35 U.S.C. § 285, but it does not plead specific facts to support pre- or post-suit knowledge of infringement beyond the filing of the lawsuit itself (Compl. p. 4).

VII. Analyst’s Conclusion: Key Questions for the Case

The subsequent disclaimer of all asserted claims during IPR proceedings is the dispositive event in this case, effectively negating the basis for the infringement action as filed. Had the case proceeded, it would likely have turned on the following questions:

1. A central question would have been one of manufacturing equivalence: Could the plaintiff prove that the accused Mitsuba power steering stators are manufactured using the specific, multi-step process recited in claim 10—namely, creating a "continuous strip" from discrete segments via interconnected "bridges"—or are they assembled using a more conventional or altogether different method?
2. The dispute would also have involved a key issue of definitional scope: How broadly would the term "retaining member" in claim 12 be construed? Would it cover any part of an overmolded housing that holds the stator segments together, or would its meaning be narrowed by the specification's examples to a distinct, separate component such as a "metal band"?