Unity of invention

Unity of invention is the requirement that a patent application may relate to one invention only, or to a group of inventions so linked as to form a single general inventive concept. It is laid down by Article L. 612-4 of the French Intellectual Property Code and Article 82 of the European Patent Convention. Unity of invention ensures that each title corresponds to one filing and search fee and that third parties can clearly identify the protected subject matter.

Assessing unity of invention

First, several inventions claimed in one application satisfy the requirement where there is a technical relationship among them involving one or more special technical features, that is, features which define the contribution of each invention over the state of the art. Second, the assessment is made against the prior art: two claims sharing an already known element are not unified by that element alone. Third, the examination may take place a priori, on reading the claims, or a posteriori, after the search report. The rules applicable before the EPO are detailed on the website of the European Patent Office.

The sanction of lack of unity

Lack of unity of invention is sanctioned only during the grant procedure and affords no ground for revocation of the granted patent. The office invites the applicant to limit its claims to a single invention or to pay additional search fees. The inventions removed from the application may become one or more divisional patent applications, which retain the filing date and priority of the initial application. The text of the Code is available on Légifrance.

Key points

In practice, unity of invention is a patent portfolio management tool. The choice to group or split inventions affects the cost of the proceedings, the legibility of the titles and the litigation strategy, because a focused patent resists invalidity attacks better and lends itself better to an infringement action. The firm advises on these choices, together with patent attorneys, as presented on the page patent litigation attorney.