MPEP 2182

2182 Scope of the Search and Identification of the Prior Art

Why should claim language under examination be given its broadest reasonable interpretation?

• to ensure that the statutory presumption of validity attributed to each claim of an issued patent is warranted by the search and examination conducted by the examiner.
• to ensure that the scope of protection afforded by patents issued are not unnecessarily limited by the latest interpretation of means-plus-statutory provisions.
• to avoid the necessity for a patent specification to become a catalog of existing technology.
  • The specification need not describe the equivalents of the structures, material, or acts corresponding to the means- (or step-) plus-function claim element.
  • A patent specification need not teach, and preferably omits, what is well known in the art.

The application of a prior art reference to a means or step plus function limitation requires that the prior art element perform the identical function specified in the claim. However, if a prior art reference teaches identity of function to that specified in a claim, then under Donaldson an examiner carries the initial burden of proof for showing that the prior art structure or step is the same as or equivalent to the structure, material, or acts described in the specification which has been identified as corresponding to the claimed means or step plus function.

A "means or step plus function" limitation should be interpreted in a manner consistent with the specification disclosure. Two-step analysis involved in construing means-plus-function limitations:

1. Define the particular function of the claim limitation.
2. Look to the specification and identify the corresponding structure for that function.
   • structure disclosed in the specification is "corresponding" structure only if the specification or prosecution history clearly links or associates that structure to the function recited in the claim.

If the specification defines what is meant by the limitation for the purposes of the claimed invention, the examiner should interpret the limitation as having that meaning. If no definition is provided, some judgment must be exercised in determining the scope of the limitation.