Laird Technologies Inc v. Graftech Intl Holdings Inc

1. Case Identification

• Case #: IPR2014-00023
• Patent #: 6,482,520
• Filed: October 7, 2013
• Petitioner(s): Laird Technologies, Inc.
• Patent Owner(s): Graftech International Holdings, Inc.
• Challenged Claims: 1-2, 21-24, and 26-29

2. Patent Overview

• Title: Thermal Management System
• Brief Description: The ’520 patent discloses a thermal management system using an anisotropic, flexible graphite sheet made from compressed particles of exfoliated natural graphite. The sheet is placed in operative contact with a heat source, such as an electronic component, to dissipate heat effectively.

3. Grounds for Unpatentability

Ground 1: Anticipation by Larson - Claims 1-2, 22-24, and 27-29 are anticipated by Larson under 35 U.S.C. §102(b).

• Prior Art Relied Upon: Larson (Patent 4,471,837).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Larson discloses every element of the challenged claims. Larson teaches a heat-sink mounting for electronic devices using a "substantially pure flexible and compressible flat graphite sheet material" commercially available under the trademark GRAFOIL®. This material is described as being formed from expanded and compacted graphite particles, and Larson explicitly shows this Grafoil® sheet in contact with a semiconductor package (the heat source).
  • Key Aspects: The central argument for anticipation rested on inherency. Petitioner contended that the claimed thermal conductivity ratio of "at least about 20" was an inherent and well-known property of the Grafoil® product explicitly identified in Larson, even though Larson did not state the ratio numerically. Therefore, Larson's disclosure of Grafoil® inherently disclosed the claimed ratio.

Ground 2: Obviousness over Larson and Grafoil® Prior Art - Claims 1-2, 22-24, and 27-29 are obvious over Larson in view of the Grafoil® Prior Art under 35 U.S.C. §103.

• Prior Art Relied Upon: Larson (Patent 4,471,837) and the Grafoil® Prior Art, including the Grafoil® Graphite Tape Article (1968), the Grafoil® Manual (1987), and the Grafoil® Specification (1994).
• Core Argument for this Ground:
  • Prior Art Mapping: This ground was presented as an alternative in case the thermal conductivity ratio was not found to be inherent in Larson. Petitioner asserted that Larson taught all limitations except for an explicit disclosure of the 20:1 thermal conductivity ratio. The Grafoil® Prior Art, which consists of publications by the Patent Owner about its own Grafoil® product, explicitly discloses that Grafoil® has a thermal conductivity ratio of at least 28:1.
  • Motivation to Combine: A POSITA would combine these references because Larson itself explicitly identifies its graphite sheet material as Grafoil®. Therefore, it would have been a matter of common sense for a POSITA seeking to understand the properties of the material in Larson to consult the manufacturer's (Patent Owner's) own technical literature, which explicitly provides the missing thermal data.
  • Expectation of Success: A POSITA would have had a high expectation of success, as they would simply be confirming a known property of a commercially available product identified in the primary reference.

Ground 3: Obviousness over Inoue and Grafoil® Prior Art - Claims 1-2, 22-24, and 27-29 are obvious over Inoue in view of the Grafoil® Prior Art under §103.

• Prior Art Relied Upon: Inoue (Japanese Laid-Open Application Number H10-56114) and the Grafoil® Prior Art (including the Grafoil® Website and Grafoil® Specification).
• Core Argument for this Ground:
  • Prior Art Mapping: Petitioner argued that Inoue teaches the fundamental concept of the invention: placing a "carbonaceous sheet" in contact with an electronic heat source (a semiconductor) to act as a heat spreader. However, Patent Owner had previously argued during reexamination that Inoue did not disclose the specific type of graphite sheet claimed (i.e., formed of compressed, exfoliated natural graphite). Petitioner contended that the Grafoil® Prior Art supplies this missing element, as it describes the exact anisotropic, flexible sheet of exfoliated natural graphite recited in the claims, including its 28:1 thermal conductivity ratio.
  • Motivation to Combine: A POSITA would combine Inoue and the Grafoil® Prior Art because both address the same problem of managing heat in electronic devices using graphite sheets. It would have been obvious to substitute the known, high-performance Grafoil® material for the generic "carbonaceous sheet" in Inoue to achieve the predictable result of improved heat spreading.
  • Expectation of Success: The combination would predictably yield a thermal management system with improved heat dissipation, as it involves using a material with known, superior anisotropic properties (Grafoil®) in a known configuration (Inoue).
• Additional Grounds: Petitioner asserted additional anticipation challenges based on the T-gon 800® Website. Further obviousness challenges were based on combinations including Inoue and the T-gon 800® Website; adding Anschel (Patent 4,914,551) for teachings on sheet size ratios; and adding the Thermagon Paper for teachings on contact pressure.

4. Key Technical Contentions (Beyond Claim Construction)

• The petition's central technical argument, woven through multiple grounds, was that the Patent Owner, Graftech, manufactured and sold the specific graphite material known as Grafoil® for decades before the ’520 patent was filed.
• Petitioner contended that Grafoil® is the exact material described and claimed in the ’520 patent and that its key properties, particularly the anisotropic thermal conductivity ratio of at least 20:1, were well-documented in the "Grafoil® Prior Art"—publications created and distributed by the Patent Owner itself.
• A core theme was that the Patent Owner allegedly concealed this prior art and its knowledge of Grafoil®'s properties from the USPTO during the original prosecution and subsequent reexaminations, thereby misleading the Examiner into allowing the claims.

5. Relief Requested

• Petitioner requested the institution of an inter partes review and a final written decision canceling claims 1-2, 21-24, and 26-29 of the ’520 patent as unpatentable.