Spectra-Physics, Inc. v. Coherent, Inc.

827 F.2d 1524 (1987)

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Spectra-Physics, Inc. v. Coherent, Inc.

United States Court of Appeals for the Federal Circuit
827 F.2d 1524 (1987)


This case involved technology regarding a laser-discharge tube assembly comprising a ceramic tube whose inner wall had copper cups and axially spaced tungsten discs attached. The tungsten discs and the copper cups dissipated heat in the discharge tube, a function needed because discharging lasers had extremely high temperatures but needed to operate at room temperature. The bond between each copper cup and the inner tube wall was thermally stressed due to the differing thermal-expansion rates of copper and ceramic. These stresses produced poor thermal contact between the copper cups and the tube, raising disc temperature and impeding the gas flow through the tube. Coherent, Inc. (defendant) initially addressed the bond problem by unsuccessfully experimenting with soldering. Coherent then investigated brazing, by which a brazing shim was placed between a copper cup and the tube inner wall, then the entire tube assembly was heated to melt the brazing material. Coherent preferred TiCuSil brazing material, a copper-silver alloy with a small percentage of titanium added. The titanium performed an active metal process, invading and wetting the ceramic to allow the copper-silver alloy to hold each copper cup to the ceramic. Without an active metal-alloy component, the ceramic had to be premetallized with a compound like moly-manganese (MoMn) to provide the metallic surface to which the copper-silver braze material could adhere. The TiCuSil active-metal process, preferred by Coherent because it did not require the premetallization step, dissuaded Coherent from investigating the MoMn process and from further experimenting with soldering. Two patents owned by Coherent respectively claimed a “means for attaching” and “permanently securing” the copper cup to the inside tube wall, but the patent specifications only disclosed pulse-soldering and the MoMn process, not the TiCuSil active-metal process beyond mentioning TiCuSil as the preferred brazing material. Spectra-Physics, Inc. (Spectra) (plaintiff) developed its own MoMn process for laser-discharge tube assemblies. Spectra sued Coherent in the United States District Court for the Northern District of California, seeking a declaratory judgment of noninfringement and invalidity as to both of Coherent’s patents and asserting that the patents failed to meet the enablement and best-mode requirements of 35 U.S.C. § 112. Coherent counterclaimed for infringement and for a validity declaration. At trial, a jury found for Coherent on all issues, and the district court entered judgment on that verdict. Later, it withdrew the judgment, finding that Coherent’s patents failed to meet the enablement requirement, despite satisfying the best-mode requirement. Coherent appealed.

Rule of Law


Holding and Reasoning (Rich, J.)

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