A Chemical Markush Claim Tests the Elasticity of “Consisting of”
Why are chemical patent claims so difficult to understand? This was the question posed during a 1961 presentation before the Division of Chemical Literature for the American Chemical Society. According to the author, “[A]ttention has been called to the ‘sometimes baffling’ and seemingly ‘absurd’ idiom in which are cast chemical patent claims.” At least some of the blame for the confusion was attributed by the author to the “so-called ‘Markush’ claim.” Thus, the author wisely advised, “[A]n understanding of the philosophy behind the Markush expression in chemical claims might help to understand better the meaning of chemical claims themselves.” More than fifty years later, and at a time where subject matter eligibility, written description, and definiteness issues are at the forefront of the patent prosecution sphere, the Federal Circuit’s decision in Multilayer Stretch Cling Film Holdings, Inc. v. Berry Plastics Corp.
, Nos. 2015-1420, -1477(Fed. Cir. Aug. 4, 2016), revisits the Markush claims and offers guidance on their proper use. More
Section 112 Again Shows Teeth
In Advanced Ground Information Systems, Inc. v. Life360, Inc.
, No. 2015-1732 (Fed. Cir. July 28, 2016), the Federal Circuit continued in the vein of Williamson v. Citrix Online, LLC
, in affirming a district court’s finding claims with a functional recitation, but insufficient structure to support that recited function, as invoking 35 U.S.C. § 112, ¶ 6, and therefore subjecting the element to construction as a means-plus-function recitation. After this construction, because sufficient structure for performing the recited function was absent in the disclosure, the claims where deemed to be indefinite under the second paragraph of § 112, ¶ 2, and therefore invalid. More