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Assumptions About Properties of Prior Art Structure Fail to Prove Inherency

May 13, 2002

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Last Month at the Federal Circuit - June 2002

Judges: Gajarsa (author), Lourie, and Clevenger

In Crown Operations International, Ltd. v. Solutia Inc., No. 01-1144 (Fed. Cir. May 13, 2002), the Federal Circuit affirmed the district court’s SJ of no invalidity concerning U.S. Patent No. 4,973,511 (“the ‘511 patent”) issued to Solutia Inc. (“Solutia”) given the lack of proof concerning the inherency of a certain prior art structure. The Federal Circuit vacated, however, the district court’s grant of SJ of no invalidity concerning U.S. Patent No. 5,091,258 (“the ‘258 patent”), because the district court had erred in its analysis of the enablement requirement and had not addressed the written-description requirement.

The patents-in-suit concern layered films used to create safety and solar control glass. Claim 1 of the ‘511 patent claims that a “control film contributes no more than 2% visible reflectance, based on total visible incident radiation, in a laminated window assembly containing said composite solar/safety film laminated to at least one rigid transparent member.”

Crown Operations International, Ltd. (“Crown”) argued that U.S. Patent No. 4,017,661 to Gillery anticipates the ‘511 patent, because it inherently discloses the 2% limitation. Crown urged the Federal Circuit to accept the proposition that if a prior art reference discloses the same structure as claimed in a patent, the resulting property should be assumed. The Federal Circuit declined to adopt this approach because it is not in accordance with its precedents on inherency, which require proof that the inherent feature must necessarily be present and recognized by one of skill in the art. Crown offered only an assumption and its own contentions, the Court observed.

The ‘258 patent discloses a method to control distortion otherwise caused by the safety and solar film layer by measuring and controlling the texture of the surface of the plasticized polyvinyl butyral layers. The method expresses texture using a “wave index” and a “roughness value.” A smoothing program calculates the wave index by determining the peaks and valleys in the surface, the pitch average amplitude, and average pitch. Claim 1 of the ‘258 patent recites a “substrate layer or functional performance layer possessing low surface waviness on each side characterized by a wave index value, WI, of less than 15,000 square micrometers.”

Crown argued that the rules disclosed by the ‘258 patent for calculating wave index are not sufficiently precise to enable a person of ordinary skill in the art to practice the ‘258 patent without undue experimentation. Crown also asserted that according to the disclosed wave-index calculations, one of ordinary skill in the pertinent art would not know whether to instruct the smoothing program to disregard a peak by comparing it to an immediately preceding peak or to a valley. The district court held that common sense and a clarifying clause provided in the smoothing rules (“a valley being at least 0.5 micrometers below the immediately preceding prior peak”) defeated Crown’s argument.

The Federal Circuit concluded, despite Solutia’s claims that a person of ordinary skill in the pertinent art could overcome any ambiguities in the wave-index calculation without undue experimentation, that the ambiguities and lack of specified boundary conditions raised a genuine issue of material fact. Accordingly, the Court remanded for proceedings concerning the enablement and writtendescription requirements of 35 U.S.C. § 112.