How is the term “substantially” interpreted in patent claims?

The term “substantially” in patent claims is often used to describe a particular characteristic of the claimed invention. According to MPEP 2173.05(b), it is considered a broad term. The interpretation depends on the context and the guidance provided in the specification. For example, in In re Nehrenberg, the limitation “to substantially increase the efficiency of the compound as a copper extractant” was found definite based on the general guidelines in the specification. Similarly, in Andrew Corp. v. Gabriel Electronics, the court held that “substantially equal E and H plane illumination patterns” was definite because one of ordinary skill in the art would understand its meaning.

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• substantially
• claim interpretation
• indefiniteness
• approximations