Functional Language in Claim

In general, a claim with functional language is very often objected by the Examiner in Korean patent practice. Examiners usually consider functional wordings or expressions used in claims rendering the scope or constitution of the claimed invention unclear and indefinite. Further, they seem to surely have the opinion that such functional expressions make the scope of the functional language claim to be unduly broader than the subject matter supported by the specification.

However, functional wordings or functional expressions are surely allowed under Korean patent practice when no alternative and effective expressions that can clearly and definitely describe the claimed subject matter; the meanings of the functional expressions are fully supported by the detailed description of the invention; and the functional expressions do not pose any problems in defining the scope of the claimed invention. For example, for the specifications of electronic technology field, functional wordings are usually and often allowed in claims. An examiner who is in charge of examinations for chemistry, biotechnology or pharmaceutical patent applications, has relatively high tendency to reject functional language claims.

Recently the Supreme Court held that the scope of protection for an invention is limited to the embodiments clearly specified in the detailed description and drawings when means-plus-function features are exceptionally allowed. The detailed descriptions and drawings of the invention are critical factors to be considered in narrowly interpreting functional claims for purposes of determining the scope of protection. Therefore, it is advisable to keep in mind that many examples should be described in the detailed description when the applicant files an application for a functional claim.