After years of slowly diverging case law, in a move that helps patent proprietors, the Enlarged Board of Appeal of the European Patent Office has decided that during opposition proceedings the assessment of claim clarity should be restricted.

Unclear beginnings

It is not possible to attack a European patent on the ground of a lack of claim clarity. However, Opposition Divisions (ODs) and Boards of Appeal have the right, and the duty, to ensure that if a patent is amended during the course of opposition proceedings then it complies with all of the requirements of the European Patent Convention.  On the face of it, that could include requiring the claims to be clear.

Murky waters

The apparent conflict between lack of clarity not being a ground of opposition and the possibly unrestricted remit of the OD and Board in assessing whether an amended claim complies with the European Patent Convention (including clarity) has led to uncertainty concerning the extent to which clarity should be assessed during oppositions. 

Historically, ODs and Boards have been resistant to clarity objections being raised in opposition proceedings, even when claims are amended.  In the Board of Appeal case T 301/87 and the Enlarged Board of Appeal case G 1/91, the precedent was set that an amendment to include features of a dependent claim into an independent claim would not open the door to an attack on that claim’s clarity, because the clarity of that subject matter was assumed to have already been assessed and allowed by the Examining Division, pre-grant. 

However, through the years, that position has shifted and the clarity of claims that have been amended to include feature(s) of granted dependent claim(s) has become more frequently assessed during opposition proceedings, for example on the grounds that the amendment to join the independent and previous dependent claim together reveals an inconsistency that gives rise to a lack of clarity. 

An example of such a shift is in the Board of Appeal case T 459/09, in which it was decided that an amendment to include a feature of a dependent claim into an independent claim could have its clarity assessed, despite there being no change to the words used in the granted claims. 

Clear reasoning?

It was in the light of that diverging case law that the Board of Appeal in case T 373/12 asked the Enlarged Board of Appeal, in case G 3/14, to decide the extent to which clarity can be assessed during opposition proceedings.

The Enlarged Board took a methodical approach to the assessment of the referred questions, assessing what it saw as the extreme views (a narrow, “conventional”, approach as set out in T 381/87 or a broad approach in which the clarity of all of the claims could be assessed), as well the various positions in between. 

In short, the Enlarged Board decided that the “conventional” approach of T 381/87 should be followed.

The Enlarged Board also considered whether rigidly following the “conventional” approach might lead to patents being upheld with unclear claims (for example, in a situation in which a lack of clarity only became evident following an amendment). Although the Enlarged Board acknowledged that those situations would be undesirable, it outlined that it was not the OD’s role to repeat the work of the Examining Division.  Therefore, the subject matter of a dependent claim, which might be incorporated into an independent claim, should have been considered in relation to clarity pre-grant, so there is no need to reassess the situation.

Accordingly, the Enlarged Board considered that a narrow approach to assessing clarity at an opposition should be taken, and that despite the potential issues it is the fairest way in which to apply the law uniformly.

A clear way going forward?

This decision obviously favours the patent proprietor.  Viewing it from the other side of the table, it does not help opponents, who have largely been blocked from taking a last roll of the dice to try to revoke a patent due to an amendment (based on a granted dependent claim) which leads to an unclear claim.

That said, despite the rhetoric from the Enlarged Board in this case, there is room for clarity to be assessed in some cases.

In the final order, the Enlarged Board commented that clarity can be assessed at an opposition if the amendment makes the claim unclear (although it appears that this is likely to be the exception rather than the rule). Additionally, the decision leaves largely unchanged the ability to challenge and have assessed the clarity of amendments based on the description rather than the granted claims.

All in all, the decision appears to show that common sense has prevailed.  As the law had previously been applied in a slightly haphazard manner, neither patent proprietors nor opponents had any certainty of how good their case was, or whether a particular strategy was likely to be successful.  At least now, we seem to have some clarity.  Patent applicants should continue to ensure that the specification that goes to grant contains sub-claims that provide a useful reservoir of language for amendments that might have to be made during opposition or litigation.