Written Description Requirement To get a patent, an inventor must satisfy the written description requirement.  This is accomplished through the preparation of a patent application which describes the invention and shows any drawings if necessary for the understanding of the invention.  To satisfy the written description requirement, the discussion of the invention must correspond to the claims. [...]

Once a patent application is filed, it receives a priority date for all that it discloses and nothing more. The inventor can claim anything within the disclosure as being a part his or her invention. If the inventor wants to claim an invention that varies from the disclosure, then the claim language must be generalized so as to encompass the variation but cannot be shifted unless the original disclosure provides “written description” of the claimed variation. Otherwise, the claim will be invalid for lack of “written description” in the specification.