T 1877/08 – Continua Are Special

[2.1] The patent in suit claims two priority dates, the first priority date being that of US 558 346 of 26 July 1990, the second priority being that of US 681 565 of 5 April 1991.

The [opponent] cited document D2 in the proceedings as representing the closest state of the art in the assessment of inventive step. This document is an intermediate document having a publication date between the first priority date of the patent in suit, which is 26 July 1990, and the filing date thereof.

Since the question arises whether document D2 is to be considered as state of the art according to A 54(2), the matter of whether or not claim 1 of the patent in suit is entitled to the claimed right of the first priority date of 26 July 1990, has to be decided by the Board.

[2.2] Pursuant to A 87(1), a right of priority may only be enjoyed in respect of the same invention. Therefore, in deciding whether claim 1 of the patent in suit is entitled to the claimed priority, it needs to be decided whether in the priority document the same invention is disclosed as in present claim 1. The requirement for claiming priority of “the same invention”, referred to in A 87(1), means that priority of a previous application in respect of a claim in a European patent (application) in accordance with A 88 is to be acknowledged only if the skilled person can derive the subject-matter of the claim directly and unambiguously, using common general knowledge, from the previous application as a whole (see G 2/98).

In the present case the priority document US 558 346 relating to the priority date of 26 July 1990 discloses refrigerant mixtures being a blend of from 30 to 55 percent by weight of chlorodifluoromethane, from 35 to 65 percent by weight of pentafluoroethane and from 2 to 10 percent by weight of propane […]. However, there is no disclosure in the priority document of a composition consisting of from 30 to 65 percent by weight of chlorodifluoromethane, from 33 to 69 percent by weight of pentafluoroethane and from 1 to 10 percent by weight of propane, as defined in present claim 1.

[2.3] Thus, claim 1 discloses ranges of numerical values different from those disclosed in the priority document. As the person skilled in the art cannot derive the subject-matter of claim 1 directly and unambiguously, using common general knowledge, from the previous application as a whole, it follows that the priority based on that previous application cannot be acknowledged.

[2.4] The [patent proprietor] argued that although the limiting values of the ranges specified in claim 1 differed from those disclosed in the priority document, the latter ranges were comprised within those claimed in the patent in suit. Consequently, at least for the overlapping portion of the ranges the subject-matter of claim 1 was entitled to the earlier priority date of 26 July 1990.

A 88(3) stipulates that if one or more priorities are claimed, the right of priority shall cover only those elements of the European patent application which are included in the application whose priority is claimed. The expression “elements” has to be understood as relating to separable alternative embodiments (G 2/98 [4. and 6.7]). In the present case, however, the claimed amounts represent a continuum of a numerical range of values which does not correspond to distinctive alternative embodiments. Consequently, no separable alternative embodiments, i.e. elements in the sense of A 88(3), can be identified within that continuum, which could enjoy the claim to the first priority date of 26 July 1990.

[2.5] For these reasons, the Board concludes that the subject-matter of independent claim 1 as a whole is not entitled to the claimed priority right regarding the first priority date of 26 July 1990.

Thus, the effective date for claim 1 of all requests is later than the publication date of document D2. Consequently, document D2 is a prior art document pursuant to A 54(2) for the subject-matter of claim 1.

It may, therefore, be a bad idea to “push the limits” in the second application (the one claiming priority) when a search report for the first application shows that the ranges could have been defined more broadly. When doing so, it is advisable to keep a claim (or at least parts of the description) with the original limits because a claim based on these limits may validly claim the priority, whereas the extended claim may not.

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