An International Guide to
Patent Case Management for Judges

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8.5.1 Claim construction

8.5.1.1 Relationship between claims and scope of protection

The scope of protection of a patented invention is the objective scope that the effects of the patent reach and is determined by what is stated in the claims.82 Accordingly, the scope of protection should be determined before the issue of infringement, and such a determination involves claim construction. Claim construction is also done before deciding whether the invention at issue lacks novelty or an inventive step. It is a matter of legal decision or evaluation, not of fact-finding, and thus may not be done via confession.

8.5.1.2 Principles of claim construction

Claims state the scope of the patented invention for which the applicant seeks to receive protection. The scope of the claims must be determined based on what is stated in the claims and cannot be broadened or narrowed based on other statements (e.g., detailed descriptions or drawings). Nevertheless, reference to the descriptions or drawings of the invention is necessary to accurately understand the technical meaning of the claims. Thus, claims should be construed in an objective and reasonable manner based on contemplation of the technical meaning sought to be expressed by the wording of the claims, on the basis of the general meaning of the wording used in the claims but also in reference to the detailed description and drawings.83 In other words, one should mainly look to the wording of the claims for claim construction (the principle of literal interpretation), but the descriptions or drawings of the invention, as well as the general technical knowledge at the time of filing, should also be given weight (the principle of reference to description).

Further, one may also refer to other documents containing the applicant’s arguments in the prosecution history, such as specifications, amendments and written arguments presented by the applicant in the course of filing, as well as opinions presented by the KIPO examiner (the principle of reference to prosecution history). However, reference to these documents should never be used to broaden or narrow the meaning of the wordings used in the claims.