PTAB

IPR2019-00583

KEMET Electronics Corp. v. MEC Resources, LLC

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1. Case Identification

2. Patent Overview

  • Title: Inductors with Minimized EMI Effect and the Method of Manufacturing the Same
  • Brief Description: The ’390 patent discloses an inductor with enhanced inductance and a method for its manufacture. The invention involves a standard inductor, comprising a magnetic core and an electrically conducting coil, which is then embedded in a magnetic resin layer using compression molding to reduce electromagnetic interference (EMI) and enhance performance.

3. Grounds for Unpatentability

Ground 1: Obviousness over Franco and Shafer - Claims 1, 3-4, 7, 9-11, 13-14, 17, 19-20 are obvious over Franco in view of Shafer.

  • Prior Art Relied Upon: Franco (“Electric Circuits Fundamentals,” 1995 textbook), Shafer (Patent 6,204,744).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner asserted that Franco taught the fundamental structure of an inductor as recited in elements (a) and (b) of independent claim 1: a magnetic core (e.g., iron or ferrite) and an electrically conducting coil wound around the core. Shafer was alleged to teach the remaining limitations, namely embedding an inductor coil within a magnetic resin layer containing magnetic powder (powdered iron) dispersed in a polymer resin (polyester resin) via a compression molding process. Shafer’s method of compression molding a magnetic resin tightly around a coil was argued to meet the limitations of embedding an outer periphery of the coil.
    • Motivation to Combine: A Person of Ordinary Skill in the Art (POSITA) would combine the teachings of Franco and Shafer to improve upon Franco's basic, exposed-coil inductor. The motivation stemmed from achieving the known, predictable benefits disclosed in Shafer, including providing physical "armor" and magnetic shielding for the coil, minimizing air space to improve performance and reduce size, increasing inductance, and reducing manufacturing costs.
    • Expectation of Success: A POSITA would have had a high expectation of success, as the combination involved applying a known manufacturing process (Shafer's compression molding) to a standard component (Franco's inductor) to achieve predictable improvements.

Ground 2: Obviousness over Franco, Shafer, and Rittner - Claims 2 and 12 are obvious over Franco and Shafer in view of Rittner.

  • Prior Art Relied Upon: Franco (textbook), Shafer (Patent 6,204,744), and Rittner (Patent 6,600,403).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground built upon the Franco and Shafer combination. Dependent claims 2 and 12 require the magnetic resin layer to have a thickness determined to match a predetermined inductance. Petitioner argued Rittner explicitly taught this concept, disclosing that the inductance value of an inductor can be precisely set by tuning the thickness of a covering paste containing ferromagnetic material.
    • Motivation to Combine: A POSITA, having already combined Franco and Shafer, would be motivated to incorporate Rittner's teaching to gain further, predictable control over the final product. This would allow for the manufacture of inductors with precise, consistent inductance values for specific applications (e.g., filtering, power supplies) and would reduce part-to-part variation, a known goal in electronics manufacturing.
    • Expectation of Success: The combination was presented as the application of a known technique (controlling layer thickness to tune inductance, from Rittner) to an existing device (the Franco/Shafer inductor) to achieve the predictable result of a precisely controlled inductance value.

Ground 3: Obviousness over Amada and Shafer - Claims 1, 3-4, 9-11, 13-14, and 19-20 are obvious over Amada in view of Shafer.

  • Prior Art Relied Upon: Amada (Patent 6,144,280), Shafer (Patent 6,204,744).

  • Core Argument for this Ground:

    • Prior Art Mapping: Petitioner argued that Amada taught a chip inductor that meets most limitations of claim 1, including a magnetic bobbin (core), a wound coil, and a protective magnetic resin coating (e.g., epoxy resin with ferrite powder) that embeds the coil. However, Amada did not explicitly disclose that its coating was applied via compression molding. Petitioner asserted that Shafer supplied this missing element, teaching a well-known method for compression-molding a magnetic resin layer around an inductor coil.
    • Motivation to Combine: A POSITA would be motivated to apply Shafer's compression molding process to Amada's inductor for several reasons. First, it would be an obvious way to achieve the uniform, rectangular cross-section with flat surfaces described by Amada, which is beneficial for automated manufacturing. Second, it would solve the problem of "air spaces" that can affect inductor performance, a benefit explicitly noted in Shafer. Third, a POSITA could substitute Shafer's iron powder material for Amada's ferrite material to create an inductor capable of handling higher currents.
    • Expectation of Success: Success was predictable because the combination involved applying a known, suitable process (Shafer's molding) to a known product (Amada's inductor) to achieve improved manufacturability and performance.

  • Additional Grounds: Petitioner asserted additional obviousness challenges based on variations of the primary combinations. These grounds argued that it would have been obvious to further modify the Franco/Shafer or Amada/Shafer combinations with teachings from: Butherus (Patent 3,953,251) for using a compression-molded magnetic resin to form the core itself; Kaneko (Patent 5,010,313) for adding an outer metal magnetic sheath for further shielding and inductance control; and Ohkawa (EP0265839A2) for substituting the thermosetting resin of Shafer with a thermoplastic polymer resin like polypropylene.

4. Key Claim Construction Positions

  • "consolidated": Petitioner contended that for the purposes of the IPR, the term "consolidated" as used in claims 5 and 15 should be construed to mean that the magnetic core and the magnetic resin layer are formed from the same material and combined into a single structure at the same time. This construction was based on a disclosure in the ’390 patent describing an embodiment where the magnetic core is eliminated and the entire coil is embedded in a matrix of the magnetic-resin mixture.

5. Relief Requested

  • Petitioner requested the institution of an inter partes review and the cancellation of claims 1-20 of the ’390 patent as unpatentable.