5.115. How is the requirement of unity of invention satisfied? Unity of invention is present only when there is a technical relationship among the claimed inventions involving one or more of the same or corresponding special technical features. The expression special technical features means those technical features that define a contribution which each of the claimed inventions, considered as a whole, makes over the prior art. The determination whether a group of inventions is so linked as to form a single inventive concept is made without regard to whether the inventions are claimed in separate claims or as alternatives within a single claim. An initial determination of unity of invention based on the assumption that the claims avoid the prior art will be made before the prior art search but may be reconsidered on the basis of the results of the search. Annex B of the Administrative Instructions contains detailed criteria governing the determination whether an international application complies with the requirement of unity of invention under Rule 13. The following paragraphs set out a summary of some of the more important criteria discussed in that Annex. Illustrations of three particular situations are explained in detail below:
(i) combinations of different categories of claims (for example – product, process, use, and apparatus or means),
(ii) so-called Markush practice and
(iii) the case of intermediate and final products.
Date retrieved: 02 November 2015