Chemcast Corp. v. Arco Industries Corp.
913 F.2d 923 (Fed. Cir. 1990)

  • Chemcast had a patent on a "grommet" (which is kind of like a gasket). Arco invented a similar grommet and tried to get a patent on it. Chemcast sued for infringement.
    • Chemcast's patent had a claim saying that the grommet could be made of two different materials, and said in general what the hardness of the materials should be, but it didn't specify what materials should be used.
    • Arco argued that Chemcast's patent was invalid because it did not properly describe the best mode as required by 35 U.S.C. 112.
      • 112 requires that the written description of a patent "shall set forth the best mode contemplated by the inventor of carrying out his invention.
  • The Trial Court found for Arco and declared the claim invalid. Chemcast appealed.
    • The Trial Court found that the claim was invalid because it failed to disclose the best mode as required by 112.
    • The Court found that Chemcast's patent was invalid because if failed to specify the particular type, hardness, supplier, and trade name of the materials used to make the grommet.
  • The Appellate Court affirmed.
    • The Appellate Court found that determining if a patent disclosed the best mode required a two part analysis:
      • Contemplation: At the time the inventor filed the patent application, did they know of a mode of practicing the invention that he considered to be better than any other?
        • This is a subjective question.
      • Concealment: If so, does the written description in the patent application provide enough information to enable someone skilled in the art to practice the best mode?
        • This is an objective question.
    • The Court looked at the facts of the case, and found that by the time Chemcast filed the patent application they knew specifically what materials would make for the best grommets. Therefore, the patent application is invalid because it just gives a general description of what kinds of material should be used, and that was not enough for someone skilled in the art to be able to know what specific material Chemcast found worked best.
      • So it did not disclose the best mode.
    • Chemcast argued that they never claimed a specific material, so they shouldn't have to disclose what material they wanted to use. However, the Court found that did not excuse them from the best mode requirement.
    • Chemcast argued that they didn't develop the material themselves, they just bought it from a chemical supplier based on what the supplier's claims of the materials properties. Chemcast didn't even know the exact formula of the material! However, the Court found that in order to meet the best mode requirement, an inventor has to at least disclose the name of the material they were using.
  • The best mode requirement is designed to stop companies like Chemcast from getting patent protection while still maintaining a trade secret.