Negative Limitation of Hair Coloring Agent Excludes A Functional Amount of Colorant
Dr. Richard Chinn reports:
In Liqwd, Inc. v. L’Oreal USA, Inc. the Fed. Cir. vacated the district court’s denial of a preliminary injunction and remanded for further proceedings, based on the district court's erroneous claim interpretation of “does not contain a hair coloring agent” as excluding any content of hair colorant, independent of whether the hair colorant was present in an amount effective to color hair. Even though the Fed. Cir. found it natural to interpret the negative limitation to only exclude functional amounts, the Fed. Cir. also found the district court's claim interpretation to be contrary to patentee’s prosecution history which explained that a “hair coloring agent” refers to a colorant which changes the color or tone of hair it is applied to.