An interesting decision was recently given by the UK High Court, in which RN Ventures was found to infringe L’Oréal’s patent for a skin care device.

It was argued that the prosecution history of the patent application should be used to determine the scope of the patent’s claims. The Court re-iterated the test provided in the recent Actavis case which stated that the prosecution history should only be taken into account if;

“(i) the point at issue is truly unclear if one confines oneself to the specification and claims of the patent, and the contents of the file unambiguously resolve the point,

or

(ii) it would be contrary to the public interest for the contents of the file to be ignored”.

Because the wording of the claims was held to be clear, the prosecution history was of no assistance in determining their scope.

It was also emphasised that “reference to the prosecution history is the exception, and not the rule” and that “parties should think carefully in future before incurring additional costs in arguing about the prosecution history”.