Tips for searching

Since some patent offices will only use the main groups for classifying their publications, some precautions have to be made when trying to do a complete search.

If searchers also want to retrieve documents from offices that only use the main group level, they must complement a search in deeper hierarchical levels of the IPC with a supplementary search in the corresponding main group.

The document content to be classified

Nowadays, most offices publish patent applications before they are examined. This means that the content of the claims at the time of publication does not necessarily reflect the “real” invention or all the material that one would like to retrieve in a search.

The rules for the IPC recommend that patent offices not only classify the content of the claims, but also other important and possibly inventive aspects of the documents found in the description, examples or drawings. All such important features are to be classified as “invention information”. Other content in a document, which whilst being of lesser importance, may still have some search value, can be classified as “additional information”.

Patent databases make a distinction between “invention information” and “additional information”, enabling more accurate searches.