The Written Description Requirement

It is now well accepted that this provision of the 1952 Patent Act (Patent Act) includes a written description requirement that is separate and distinct from the enablement requirement. Thus, a specification may enable one of ordinary skill to make or use a claimed invention, but still not adequately describe the invention in a way that the public knows that the inventor was in possession of the claimed invention at the time of filing the application. For example, a patent specification that discloses various patterns of eight wooden shingles, does not necessarily provide written description for a claim amendment that recites “at least six shingles,” even though the specification would enable one so inclined to construct a panel of at least six wooden shingles. However, it was not entirely clear from the language of the Patent Act itself that there was a written description requirement separate and distinct from the enablement requirement.

The well-accepted understanding that these are separate and distinct requirements flows from judicial decisions, and not the text of the Patent Act itself.