How are “wherein” and “whereby” clauses interpreted in patent claims?

The interpretation of “wherein” and “whereby” clauses in patent claims depends on their specific context and effect on the claim. According to MPEP 2111.04:

“The determination of whether each of these clauses is a limitation in a claim depends on the specific facts of the case.”

For “wherein” clauses, they can be limiting if they give “meaning and purpose to the manipulative steps” as noted in Griffin v. Bertina.

For “whereby” clauses, the Hoffer v. Microsoft Corp. case provides guidance:

• If a “whereby” clause states a condition that is material to patentability, it cannot be ignored.
• However, in a method claim, a “whereby” clause that simply expresses the intended result of a process step positively recited is not given weight.

Patent attorneys and examiners should carefully analyze these clauses to determine if they add limitations to the claim or merely state the intended result of other claim elements.

Claim Scope Not Limited by Optional Steps MPEP 2111.04 Permitted
Claim Limitation Depends on Specific Facts MPEP 2111.04 Informative
Wherein Clause Limits Process Claim When Giving Purpose to Steps MPEP 2111.04 Informative
Adapted to Clause Limits Machine Claim When Described Narrowly MPEP 2111.04 Informative
Whereby Clause Must Not Change Substance of Invention MPEP 2111.04 Prohibited