What rejections should be considered for unsupported means-plus-function limitations?

When a means- (or step-) plus-function limitation in a claim is not supported by corresponding structure, material, or acts in the specification, the examiner should consider the following rejections under 35 U.S.C. 112:

  • Enablement (35 U.S.C. 112(a)): If the skilled artisan would not know how to make and use the invention without a description of elements to perform the function.
  • Written Description (35 U.S.C. 112(a)): If the specification does not describe the claimed invention in sufficient detail to demonstrate possession of the claimed invention.
  • Indefiniteness (35 U.S.C. 112(b)): As being unclear or ambiguous due to lack of corresponding structure.

The MPEP provides specific guidance for computer-implemented means-plus-function limitations:

“If the means- (or step-) plus-function limitation is computer-implemented, and the specification does not provide a disclosure of the computer and algorithm in sufficient detail to demonstrate to one of ordinary skill in the art that the inventor possessed the invention, see MPEP § 2161.01 and MPEP § 2181, subsection IV, a rejection under 35 U.S.C. 112(a) or pre-AIA 35 U.S.C. 112, first paragraph, for lack of written description must be made.”

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Topics: First Or Second Paragraphs, MPEP 2100 - Patentability, MPEP 2185 - Related Issues Under 35 U.S.C. 112(A) Or (B) And Pre - Aia 35 U.S.C. 112, Patent Law, Patent Procedure
Tags: 35 u.s.c. 112(a), 35 U.S.C. 112(B), Enablement, indefiniteness, means-plus-function, Written Description