Corning Glass Works v. Sumitomo Electric U.S.A., Inc.

868 F.2d 1251 (1989)

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Nature of the Case

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Facts

Corning (P) developed optical fiber with a pure fused silica cladding and a fused silica core containing approximately three percent by weight of titania as the dopant in the core. Due to the careful selection of the core diameter and refractive index (RI) differential between the core and the cladding that P's product began to meet an attenuation of 20 db/km, the approximate transmission efficiency of the copper wire commonly used in telephone communications. Bell Laboratories confirmed the attenuation measurements and considered P's achievement an important breakthrough, making long-distance optical telecommunications possible. The announcement created enormous interest and was the subject of many articles in both technical and general publications. This advancement in technology won P accolades from various societies and institutes, for which they were presented with many prestigious awards and honors. The invention of the '915 patent has achieved impressive commercial success on a worldwide basis. The district court determined that 'the 915 patent clearly covers a basic, pioneering invention.' The '915 patent is disclosed as having a doped fused silica core and a fused silica cladding (doping optional), wherein the RI of the core is greater than that of the cladding. Prior to the filing date, the inventors had experimented with dopants which increased the RI of fused silica, e.g. titania, and the '915 specification mentions only such positive dopant materials. At the time the application was filed, the inventors did not know of specific dopants that would decrease the RI of fused silica, although it had been known in the art since 1954 that the introduction of fluorine decreases the RI of certain multicomponent glasses. P sought to develop a low attenuation fiber which did not require heat treatment. By doping a fused silica core with germania, which also had the advantage of transmitting more light than using titania the '550 patent was issued. P also invented a process by introducing a chlorine-containing drying atmosphere into the furnace during the 'consolidation' phase. This was the '454 Patent. Ds are engaged in the manufacture and sale of optical waveguide fibers. Ds are engaged in the manufacture and sale of optical waveguide fibers. Ds sought a declaration of invalidity and noninfringement of P's '915 and '454 patents with a counterclaim by P alleging Ds' infringement of those patents, and a suit by P against Ds asserting infringement of the '915, '550, and '454 patents. The court found infringement on the '915 patent and claim 1 of the '550 patent but found no infringement of the '454 patent. Both parties appealed. D, in part, alleges clear error in the court's finding of equivalency.