DCT

0:18-cv-01669

Nitto Denko Corp v. Hutchinson Technology Inc

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I. Executive Summary and Procedural Information

  • Parties & Counsel:
  • Case Identification: 0:18-cv-01669, D. Minn., 07/16/2018
  • Venue Allegations: Venue is alleged to be proper based on Defendant HTI’s principal place of business being located in the District of Minnesota. The case was initially filed in the District of New Jersey and was transferred based on HTI's representation that venue would be appropriate in Minnesota.
  • Core Dispute: Plaintiff alleges that Defendant’s flexures for hard-disk drives, and the methods for manufacturing them, infringe six patents related to flexure terminal design, wiring patterns, positioning features, and manufacturing processes.
  • Technical Context: The technology involves flexures, which are flexible printed circuits that serve as the critical data connection between the magnetic read/write head and the larger circuitry of a hard-disk drive (HDD).
  • Key Procedural History: The complaint states that the lawsuit was originally filed in the District Court for the District of New Jersey and was subsequently transferred to the District of Minnesota upon agreement of the parties.

Case Timeline

Date Event
2001-07-17 U.S. Patent No. 6,841,737 Priority Date
2002-03-12 U.S. Patent No. 7,007,379 Priority Date
2005-01-11 U.S. Patent No. 6,841,737 Issues
2006-03-07 U.S. Patent No. 7,007,379 Issues
2008-12-03 U.S. Patent No. 7,923,644 Priority Date
2009-08-26 U.S. Patent No. 8,692,126 Priority Date
2009-09-11 U.S. Patent No. 8,895,870 Priority Date
2010-08-06 U.S. Patent No. 8,658,906 Priority Date
2011-04-12 U.S. Patent No. 7,923,644 Issues
2014-02-25 U.S. Patent No. 8,658,906 Issues
2014-04-08 U.S. Patent No. 8,692,126 Issues
2014-11-25 U.S. Patent No. 8,895,870 Issues
2018-07-16 Complaint Filed

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

U.S. Patent No. 6,841,737 - "Wired circuit board"

  • Patent Identification: U.S. Patent No. 6,841,737, "Wired circuit board," issued January 11, 2005 (Compl. ¶26).

The Invention Explained

  • Problem Addressed: The patent addresses the problem of physical weakness in terminal portions of wired circuit boards known as "flying leads," where both sides of a conductive pattern are exposed for connection. These exposed areas are subject to stress concentration during the bonding process, which can lead to disconnection and failure (’737 Patent, col. 1:45-54).
  • The Patented Solution: The invention proposes reinforcing the conductive pattern at the points where it crosses the edges of the opening that creates the flying lead. This is achieved by either forming "widened portions" in the conductive pattern itself or by adding "projections" from the insulating layers above and below the conductor that partially cover it at the stress points, thereby enhancing its physical strength (’737 Patent, Abstract; col. 2:26-40; Fig. 1).
  • Technical Importance: By strengthening the terminal connections, the invention aims to prevent breakage during manufacturing, thereby improving bonding reliability, increasing manufacturing yield, and prolonging the useful life of the HDD (Compl. ¶27).

Key Claims at a Glance

  • The complaint does not identify any specific claims asserted. Claim 3 is a representative independent claim directed to the "widened portions" embodiment.
  • Essential elements of independent Claim 3 include:
    • A wired circuit board comprising a first insulating layer, a conductive pattern on the first insulating layer, a second insulating layer on the conductive pattern, and an opening through the insulating layers to form a terminal portion where both sides of the conductive pattern are exposed.
    • The conductive pattern has "widened portions" that extend widthwise in the areas where the edges of the opening and the conductive pattern cross.
  • The complaint does not explicitly reserve the right to assert dependent claims.

U.S. Patent No. 7,923,644 - "Printed circuit board and method of manufacture the same"

  • Patent Identification: U.S. Patent No. 7,923,644, "Printed circuit board and method of manufacture the same," issued April 12, 2011 (Compl. ¶38).

The Invention Explained

  • Problem Addressed: The patent notes that advancements in hard disk drive technology, such as Perpendicular Magnetic Recording (PMR), require larger electrical currents for writing data, which necessitates lower impedance in the wiring traces to avoid signal degradation and bit-errors (’644 Patent, col. 1:47-51; Compl. ¶39).
  • The Patented Solution: The invention discloses a specific "interleaved" arrangement of two signal line pairs (e.g., a first and second wiring pattern, each with two lines). In this arrangement, a line from the first pair is located between the two lines of the second pair, and a line from the second pair is located between the two lines of the first pair. This structure increases the area in which the wiring patterns are opposite each other, which increases capacitance and reduces characteristic impedance (’644 Patent, col. 2:1-12, col. 17:34-42).
  • Technical Importance: This interleaved wiring pattern is intended to lower impedance, which is crucial for the high-fidelity transmission of large data streams in high-capacity HDDs, thereby reducing the bit-error rate (Compl. ¶39).

Key Claims at a Glance

  • The complaint does not identify any specific claims asserted. Claim 1 is a representative independent product claim.
  • Essential elements of independent Claim 1 include:
    • A printed circuit board with an insulating layer and first and second wiring patterns on one surface.
    • The first pattern has first and second lines; the second pattern has third and fourth lines.
    • The lines are arranged such that one of the first/second lines is located between the third and fourth lines, and one of the third/fourth lines is located between the first and second lines.
    • The board includes an intersection region where one wiring pattern line is divided to allow a line from the other pattern to pass between the divided portions.
  • The complaint does not explicitly reserve the right to assert dependent claims.

U.S. Patent No. 8,692,126 - "Wired circuit board and producing method thereof"

  • Patent Identification: U.S. Patent No. 8,692,126, "Wired circuit board and producing method thereof," issued April 8, 2014 (Compl. ¶50).
  • Technology Synopsis: The patent relates to improving the accuracy of "reference holes" used to position the magnetic head on the flexure during assembly. The invention describes forming a "stepped portion" around the reference hole on the metal supporting layer, which is alleged to enable more uniform and accurate etching of the hole, thereby improving alignment and manufacturing yield (Compl. ¶51; ’126 Patent, Abstract).
  • Asserted Claims: The complaint does not specify which claims are asserted (’126 Patent).
  • Accused Features: HTI's infringing activities are alleged to include flexures incorporated in hard drives identified as "WD Blue 2.5 inch/1TB (WD10JPVX)" (Compl. ¶52).

U.S. Patent No. 8,895,870 - "Printed circuit board and method of manufacture the same"

  • Patent Identification: U.S. Patent No. 8,895,870, "Printed circuit board and method of manufacture the same," issued November 25, 2014 (Compl. ¶62).
  • Technology Synopsis: The patent claims a novel configuration for "lead wires," which are temporary conductors used to supply current for electroplating during manufacturing. The invention's configuration allegedly minimizes internal signal reflections, reducing the bit-error rate, and allows the lead wires to remain on the final product without compromising performance (Compl. ¶63; ’870 Patent, Abstract).
  • Asserted Claims: The complaint does not specify which claims are asserted (’870 Patent).
  • Accused Features: HTI's infringing activities are alleged to include flexures incorporated in hard drives identified as "WD Blue 2.5 inch / 1TB (WD10JPVX)" (Compl. ¶64).

U.S. Patent No. 7,007,379 - "Production method of printed circuit board"

  • Patent Identification: U.S. Patent No. 7,007,379, "Production method of printed circuit board," issued March 7, 2006 (Compl. ¶74).
  • Technology Synopsis: The patent discloses a manufacturing method designed to control variations in the thickness of circuit patterns at a low cost. The method involves forming a "dummy pattern" on the supporting substrate at the same time as the primary circuit pattern; this dummy pattern is later removed simultaneously with unnecessary parts of the substrate, which helps maintain uniform current density during plating and thus uniform thickness (’379 Patent, Abstract; Compl. ¶18).
  • Asserted Claims: The complaint does not specify which claims are asserted (’379 Patent).
  • Accused Features: HTI's infringing activities are alleged to include flexures incorporated in hard drives identified as "WD Red 3.5 inch / 3TB (WD30EFRX)" (Compl. ¶75).

U.S. Patent No. 8,658,906 - "Printed circuit board assembly sheet and method for manufacturing the same"

  • Patent Identification: U.S. Patent No. 8,658,906, "Printed circuit board assembly sheet and method for manufacturing the same," issued February 25, 2014 (Compl. ¶85).
  • Technology Synopsis: The patent claims an assembly sheet used for manufacturing multiple flexures, which includes features to prevent the sheet and the flexures on it from curling or warping. This reduction in warpage is alleged to raise manufacturing yield and facilitate the subsequent bonding of the flexure to the suspension arm in an HDD (Compl. ¶86; ’906 Patent, Abstract).
  • Asserted Claims: The complaint does not specify which claims are asserted (’906 Patent).
  • Accused Features: HTI's infringing activities are alleged to include flexures incorporated in hard drives identified as "WD Red 3.5 inch / 3TB (WD30EFRX)" (Compl. ¶87).

III. The Accused Instrumentality

Product Identification

  • The accused instrumentalities are flexures designed, manufactured, used, and sold by HTI, which are incorporated into suspension assemblies for hard disk drives (Compl. ¶¶17-18, 20). Specific end-products containing the accused flexures are identified as Western Digital hard drives, including models "WD Blue 3.5 inch / 500GB (WD5000AAKX)," "WD Blue 2.5 inch / 1.0 TB (WD10JPVX)," and "WD Red 3.5 inch / 3TB (WD30EFRX)" (Compl. ¶¶28, 40, 75, 87).

Functionality and Market Context

  • Flexures are described as thin, flexible metal strips containing microscopic electrical wiring traces that function as a "superhighway" for data moving between the magnetic read/write head and the main HDD circuit board (Compl. ¶7). A diagram in the complaint depicts the structural assembly of a flexure with other HDD components, showing its position relative to the base plate, beam, hinge, and slider (Compl. ¶10). The complaint alleges that flexures are the "highest value-added component of a suspension" and that HTI and Plaintiff Nitto are two of only a few suppliers that manufacture modern flexures using additive processes (Compl. ¶¶8, 13).

IV. Analysis of Infringement Allegations

The complaint does not contain detailed infringement contentions or claim charts mapping specific product features to claim elements. The analysis below is based on the general allegations in the complaint.

'737 Patent Infringement Allegations

Claim Element (from Independent Claim 3) Alleged Infringing Functionality Complaint Citation Patent Citation
a wired circuit board comprising a first insulating layer, a conductive pattern formed on the first insulating layer, a second insulating layer formed on the conductive pattern, and an opening...to form a terminal portion... HTI flexures incorporated in hard drives identified as “WD Blue 3.5 inch / 500GB (WD5000AAKX),” which are alleged to be wired circuit boards with terminals for HDD circuitry (Compl. ¶¶27-28). ¶27, ¶28 col. 7:25-39
wherein the conductive pattern has widened portions formed to extend in a widthwise direction substantially orthogonal to an extending direction of the conductive pattern in crossing areas where ends of the opening and the conductive pattern cross each other. The accused HTI flexures are alleged to embody Nitto's technology for "novel and strengthened flexure terminals for connections to magnetic heads and hard drive circuitry" (Compl. ¶¶18, 27). ¶18, ¶27 col. 7:41-49
  • Identified Points of Contention:
    • Factual Question: The primary point of contention will be factual: do the accused HTI flexures incorporated in the identified Western Digital hard drives actually contain "widened portions" on their conductive patterns at terminal locations as required by the claim? The complaint offers no direct evidence, such as micrographs or technical specifications, to support this allegation.
    • Scope Question: If the accused products contain features that arguably strengthen the terminals, a dispute may arise over whether those features meet the specific definition of "widened portions formed to extend in a widthwise direction substantially orthogonal" to the conductor's path.

'644 Patent Infringement Allegations

Claim Element (from Independent Claim 1) Alleged Infringing Functionality Complaint Citation Patent Citation
A printed circuit board, comprising: an insulating layer; first and second wiring patterns that are formed on one surface of the insulating layer... HTI flexures incorporated in hard drives identified as “WD Blue 2.5 inch / 1.0 TB (WD10JPVX),” which are alleged to be printed circuit boards with wiring patterns (Compl. ¶¶39-40). ¶39, ¶40 col. 17:7-9
the first and second lines of the first wiring pattern and the third and fourth lines of the second wiring pattern are arranged such that any one of the first and second lines is located between the third and fourth lines and any one of the third and fourth lines is located between the first and second lines... The accused HTI flexures are alleged to use "novel wiring patterns for the wiring traces in high-density disk drive flexures for reducing impedance of wiring patterns" through an "interleaved wiring trace pattern" (Compl. ¶¶18, 39). ¶18, ¶39 col. 17:13-20
a first intersection region...wherein...a portion of the first or second line of the first wiring pattern...is divided, a portion of the third or fourth line of the second wiring pattern...is arranged...to pass through a portion in between divided portions... The complaint does not provide sufficient detail for analysis of this element. — col. 17:21-33
  • Identified Points of Contention:
    • Technical Question: The central dispute will likely concern the actual physical layout of the wiring traces on the accused HTI flexures. The infringement allegation depends on whether those traces use the specific interleaved and intersecting structure recited in the claim, including the division of one line to allow another to pass through it.
    • Evidentiary Question: What evidence does the complaint provide that the accused products' wiring traces are arranged in the claimed interleaved manner? The complaint makes a functional allegation (lower impedance) but does not provide structural evidence of how that function is achieved in the accused product.

V. Key Claim Terms for Construction

For the ’737 Patent

  • The Term: "widened portions"
  • Context and Importance: The entire infringement theory for the asserted product claim of the ’737 Patent rests on whether the accused flexures possess "widened portions" at their terminals. The construction of this term will define the structural scope of the invention and determine if HTI's designs, whatever they may be, fall within it.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The specification states that the "widened portions 22 may be formed in any shape other than the generally round shape, as long as they are shaped to protrude widthwise and have widths larger than the usual width" (’737 Patent, col. 8:10-13).
    • Evidence for a Narrower Interpretation: The patent's figures and detailed descriptions show specific embodiments, including a "generally round shape" and a structure that creates a "dumbbell shape" (’737 Patent, Fig. 2; col. 8:52-54). The specification also provides preferred dimensional ratios, stating the maximum widthwise length is "1.1-4 times, or preferably 2-3 times, as longer as a usual line width" (’737 Patent, col. 8:66-col. 9:1).

For the ’644 Patent

  • The Term: "intersection region"
  • Context and Importance: Claim 1 requires a highly specific structure within this "intersection region," where one line is divided and another passes through it, with connections made via a separate connecting layer. The definition of this term is critical because infringement requires not just an interleaved pattern but also this complex intersection structure. Practitioners may focus on this term because if the accused devices achieve interleaving without this specific intersection, they may not infringe.
  • Intrinsic Evidence for Interpretation:
    • Evidence for a Broader Interpretation: The term itself is general. The claim language defines its functional components (dividing a line, passing another through) without strictly limiting its physical implementation beyond what is written.
    • Evidence for a Narrower Interpretation: The specification consistently illustrates the "intersection region" as a structure requiring "first and second through holes in the first intersection region" and a "first connecting layer" on the opposite side of the insulating layer to electrically connect the divided portions of the line (’644 Patent, col. 2:20-28; Fig. 4). This suggests the "intersection region" inherently requires a structure that passes through the substrate, not merely a planar crossover.

VI. Other Allegations

  • Indirect Infringement: For each asserted patent, the complaint alleges that HTI induced and contributorily caused its customers and end users to infringe (e.g., Compl. ¶¶29, 41). The allegations are based on HTI having "encouraged the end users to use" the infringing products and knowledge that the products were made for an infringing use (e.g., Compl. ¶¶32, 34). It further alleges the products are not "commonly available items with substantial non-infringing uses" (e.g., Compl. ¶35).
  • Willful Infringement: The complaint alleges willful infringement for all six patents. The basis for this allegation is that "HTI was aware of the ['###] patent prior to the filing of this lawsuit" and that the infringement "has been, and continues to be, willful and deliberate" (e.g., Compl. ¶¶30, 36).

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

  1. Evidentiary Sufficiency: A primary issue for the case will be one of evidentiary support. Can Plaintiff, through discovery, produce technical evidence demonstrating that HTI's accused flexures practice the specific and varied technologies claimed across the six asserted patents—from the "widened portions" of the '737 patent to the anti-warping "assembly sheet" of the '906 patent? The complaint's infringement allegations are currently conclusory and lack specific factual support.
  2. Claim Construction and Technical Mismatch: The dispute will likely focus on claim scope versus technical implementation. For example, regarding the '644 patent, a key question will be whether HTI's wiring patterns, even if functionally similar, possess the precise "intersection region" structure—with a divided line, through-holes, and a connecting layer—required by the claims, or if they represent a fundamentally different and non-infringing design.
  3. Patent-by-Patent Infringement: Given the assertion of six distinct patents covering different aspects of flexure technology (e.g., structural features, manufacturing methods), a central question will be one of infringement on a patent-by-patent basis. The case will require discrete analyses of different accused products and processes against distinct claim sets, raising the possibility of varied outcomes for each asserted patent.