On March 29, 2022, a federal judge in the state of Illinois’s federal court invalidated the claims of a plaintiff’s patent as being “indefinite” under 35 U.S.C. §112. The individual plaintiff was suing HP, Inc. for induced infringement of his document archival patent. A copy of the full text of the invalidated patent can be found at the following link: patents.google.com/patent/US7447713B1
For a patent to be “indefinite” this means the specification, which includes the abstract, drawings, summary, and description of the invention, fails to adequately inform a person having skill in the art of the scope of the invention with reasonable certainty. In other words, for a patent claim to be “indefinite,” this usually means a term or phrase in the patent is unclear or not properly elaborated on in the specification.
For example, the unclear phrase at issue in the recent Illinois case was “without substantial redundancy.” This phrase doesn’t adequately inform someone reading the patent claims or specification just exactly how little redundancy is required for the invention. All that someone knows is the invention doesn’t have substantial redundancy, whatever that means.
Relative terms like “substantial,” “approximately,” “maximum,” “minimum,” etc., usually give patents indefinite validity issues. While these terms can be used in a valid patent, it is important for inventors and patent attorneys alike to clearly define what is meant by these terms in the specification, or risk invalidation of a patent that the inventor or a corporation has often invested significant resources into acquiring.