Any oppositions filed are copied to the public file and forwarded to the patentee. Where there are multiple oppositions, proceedings are consolidated.
Each opposition is examined for formal defects, and if defects are found the opponent is invited to correct them (where correctable). Major defects will, if not corrected within the opposition period, lead to rejection of the opposition as inadmissible.
At the end of the opposition term (unless all oppositions are inadmissible), the patentee is given a period to reply with arguments or amendments. If amendments are filed, the opponents are given a period to comment in reply.
There is no formal provision for further written stages, but in practice the parties often file further documents, evidence or arguments, and the patentee may propose further amendments.
An Opposition Division of (at least) three examiners is appointed. Typically, the Rapporteur (the examiner who is actively involved in the early examination of the opposition papers) is the same individual who conducted the pre-grant examination of the application. It is therefore unlikely that he, at least, will be impressed by an opposition which merely reiterates arguments already dealt with in prosecution; an opponent is well advised to include a new objection from the outset. The other two members of the Opposition Division (one of whom is the Chairman) must not have been involved in the grant process. The Opposition Division may include an EPO in-house lawyer if witnesses are to be examined.
Unless occasioned by some action of the other party, newly filed citations filed outside the opposition period are formally regarded as "late filed" and hence only admitted with consent of the Opposition Division. The Opposition Division's discretion to admit late filed documents may be exercised if:
- the new documents are prima facie likely to prejudice the patent; or
- there is some sound reason why they were not found before the end of the Opposition period.
An opponent's own prior publications or uses are therefore rarely accepted if filed outside the opposition period. Similarly, amendments filed outside the period for response to the opposition may be disregarded as being late-filed, although this is rare in practice.
The EPO has extensive inquisitorial powers to order production of documents, inspect equipment, issue letters rogatory and hear witnesses on oath through the European national courts, but these powers are almost never used in practice.
At some point (typically several years after the filing of the opposition) the Rapporteur will review all the papers filed, and form a preliminary view.
WHOLLY WRITTEN PROCEEDINGS
If the Rapporteur finds points that require clarification, he may write to the parties requesting information. The Opposition Division can also write to other parties (e.g. libraries), but these inquisitorial powers are rarely used. In the rare event that neither party has requested oral proceedings (in other words, a hearing) the Rapporteur will then consult the remaining members of the Division and issue a written Decision terminating the opposition.
If one or more parties have so requested, or if the Opposition Division so requires (which is rare), the parties will be summoned to oral proceedings. The summons will set a date, typically six months or so later. Accompanying the summons will be a summary of the issues. Sometimes this merely lists the major points in dispute, but often it includes a preliminary view of the merits of the case. The summons will set a date for the close of written submissions, typically one month before the hearing. New documents, or amendments, are only admitted with extreme reluctance after this date.
Amendments to the patent are at the discretion of the Opposition Division and are only allowed if:
- they are intended to overcome some ground of invalidity;
- they do not go beyond what is necessary and appropriate;
- they do not introduce a lack of clarity; and
- they do not broaden the claims.
However, amendments may result in multiple independent claims without generating a lack of unity objection. Several alternative sets of amendments ("auxiliary requests") may be filed, to allow the Opposition Division to uphold a narrower text if the patentee's preferred text is found invalid.
The hearing itself is short - typically no longer than one day long. Each party has an opportunity to speak, and the opponents speak first (typically in the order in which their oppositions were filed).
The Opposition Division is presumed to be generally familiar with the technical field and have read the papers in advance, and therefore do not encourage lengthy repetition of written submissions.
Only European Patent Attorneys or European lawyers have the right to present the case for the patentee or opponent (in fact, lawyers only very rarely appear at the EPO), but experts or witnesses of fact may testify if they were notified to the other parties and the EPO well before the hearing.
The hearing will be in the language of prosecution of the patent (English, French or German), but free, simultaneous interpretation between this and the other two official languages of the EPO will be provided if requested a month in advance by one of the parties.
The general rule is: be prepared. The Opposition Division will assume an advocate to be fully familiar with all the papers in the case. New arguments and, occasionally, new citations or amendments, arise at the hearing, and it is rare to be granted more than a brief recess to deal with these.
At the close of the hearing, the Opposition Division will withdraw to discuss the case, and almost invariably will then reconvene later to issue an oral decision on the substance of the opposition. The decision will either:
- revoke the patent;
- uphold the patent; or
- uphold the patent in amended form.
Generally, each side bears its own costs (i.e. attorney fees and witness costs), but oppressive conduct, such as late filing of documents, leaves a party open to a costs order. Where costs are requested, it is at the hearing, and evidence of the level of costs should be taken to the hearing. Awards of costs are relatively rare. Any order on a costs request will be made at the close of the hearing.