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Double or quits – double patenting at the EPO

13th Mar 2012

In a recent decision, T 1491/06, by the Boards of Appeal of the European Patent Office (EPO), further guidance has been given as to when double patenting objections can be raised. The Board ruled that whilst double patenting is cause to reject a patent application, claims in a parent and divisional relating to overlapping, but non-identical, subject matter should not be objected to.

The application of double patenting objections by the EPO has been a source of great debate in the last few years. This is true not only for practitioners and other users of the system, but also between different boards of the EPO who cannot seem to agree on whether or not a provision against double patenting exists within the European Patent Convention, and if it were to exist, how to apply such an objection consistently.

In T 1491/06 the Board were considering a decision by the Examining Division to refuse a divisional application on the grounds that the claims being examined were identical to those of the parent application. The claims related to a calculating apparatus for processing terms known as “transform coefficients”, and avoiding an error introduced when performing a particular calculation known as an “inverse orthogonal transform”. During the appeal proceedings the applicant amended the claims of the divisional in question to refer to, among other things, a specific type of transform coefficient used when performing a specific type of orthogonal transform. This narrowing amendment was considered sufficient by the Board to distinguish the parent from the divisional as far as the double patenting objection was concerned.

In reaching this conclusion the Board turned to two earlier cases by the Enlarged Boards of Appeal, G 1/05 and G 1/06, in which the general principle of a prohibition of double patenting was raised on the basis that:

an applicant has no legitimate interest in proceedings leading to the grant of a second patent for the same subject-matter if he already possess one granted patent therefor.

In addition, the board were swayed by earlier Board of Appeal decision T 1391/07. This decision again relates to a divisional application that claimed overlapping subject matter with the parent. The Board, in this case, concluded that it was acceptable for the scope of protection of a parent and a divisional to overlap with each other in the sense that:

some, but not all of the embodiments notionally encompassed by one of the claims would also be encompassed by the other one of the claims.

The Board in T 1491/06 felt that the claims of the divisional application, as amended, overlapped with the parent, but only partially so, and that this was enough to escape the double patenting objection.

This decision relates to a rather specific situation in which there is only some overlap between claims of a parent and divisional, but does not definitively answer the question of whether the double patenting objection will bite when the subject matter of a divisional is entirely encompassed by the parent (or vice versa). On this question, a number of conflicting decisions such as T 587/98, T 307/03 and T 1423/07 exist.

It would appear that this question is ripe for referral to an Enlarged Board of Appeal. However, until the clarity of an Enlarged Board decision is forthcoming, we advise applicants to be vigilant when filing divisional applications for similar subject matter to that of the parent, and where possible to ensure that the divisional and parent claims do not claim wholly overlapping subject matter.

This article is for general information only. Its content is not a statement of the law on any subject and does not constitute advice. Please contact Reddie & Grose LLP for advice before taking before any action in reliance on it.

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