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
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 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
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
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
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
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