T 0433/93 (Re-hearing) vom 06.12.1996

I. If an Opposition Division wishes to introduce a new ground of opposition into the proceedings in addition to the ground(s) substantiated in the notice of opposition, either of its own motion or upon request by an opponent, the patent proprietor must be informed (normally in writing) not only of the new ground of opposition (ie the new legal basis for the opposition), but also of the essential legal and factual reasons (ie its substantiation) which could lead to a finding of invalidity and revocation. Thereafter the patent proprietor must have a proper opportunity to present comments in reply to the new ground and its substantiation.

II. Following a substantial procedural violation in connection with a decision issued by a first instance department, at the request of a party, such decision has to be set aside. If a party has reasonable grounds to suspect that the same composition of Opposition Division would be tainted by the previous decision and therefore partial, at the request of that party the case should be re-heard before a different composition of Opposition Division.