A recent decision by the EPO’s Boards of Appeals, T 1811/13, considers whether a lack of clarity in a claim can give rise to an allowable objection to insufficiency of disclosure.

The patent in question relates to a liquid container detachably mountable to a recording apparatus. The patent was granted with claim 1 comprising a number of features including a feature referred to as e1. During the preceding opposition proceedings, the patent was amended to include a further feature referred to as e2.

In the appeal, the opponent objected to the features e1 and e2 of claim 1 as lacking clarity under Article 84 EPC 1973. The opponent further argued that, due to this lack of clarity, the skilled person would not know whether they were working within the features of the claim or not. Hence, the opponent submitted that the aspects of claim 1 relating to the features e1 and e2 were insufficiently disclosed under Article 83 EPC 1973.

In assessing clarity, the Board rejected the opponent’s objections. The Board stated that feature e2 was sufficiently clear to be understood by the skilled person. Furthermore, the Board asserted that e1 could not be objected to during opposition appeal proceedings because it was present in claim 1 as granted. The Board cited decision G 3/14 of the Enlarged Boards of Appeal in support of this assertion. Thus, claim 1 was determined to be clear as required by Article 84 EPC 1973.

In addressing the sufficiency of disclosure, the Board referred to Technical Board decision T 256/87 of 26 July 1988. In this decision, it was first determined that claim 1 was clear. It was then stated: “The further question then arises, however, of whether this information, although clear in itself, is sufficient to enable the skilled person to carry out the invention in the sense of his (a) being able to establish whether a composition containing an amount of EAC falling within the range claimed, and (b) being able reliably to prepare such a composition”.

The Board analysed how this decision has been applied in subsequent cases since 2003. They noted two approaches in how the decision had been applied. The first approach was found in four decisions issued by one board between 2004 and 2007. In these decisions, it was found that the skilled person would not know whether they were working within the area covered by the claim. As a result, the claimed invention was not disclosed in a manner sufficiently clear and complete for it to be carried out by the skilled person. The Board further comments that these decisions appear not to have been followed since 2007.

The second approach was found in more than twenty decisions issued by various boards since 2003 (including T 1948/10, T 608/12, T 2331/11 and T 1507/10). In these decisions, it was determined that the definition of the scope of a claim was related to clarity under Article 84 EPC rather than sufficiency of disclosure under Article 83 EPC.

As a result of this analysis of past decisions, the Board determined that “there is agreement or at least a clearly predominant opinion among the boards that the definition of the "forbidden area" of a claim should not be considered as a matter related to Article 83 EPC. The present board shares this opinion”.

The Board further clarified its positon on the matter by acknowledging that a lack of clarity may result in an insufficient disclosure of the invention in certain cases. However, the Board asserted that establishing that the claims lack clarity does not necessarily mean that there is a lack of compliance with Article 83 EPC 1973. Instead, it must be shown that the lack of clarity affects not just the claims but the patent application as a whole. In other words, the lack of clarity must be such that the skilled person cannot carry out the invention.

The Board concluded that this requirement had not been demonstrated by the opponent in this case. Thus, the appeal of the opponent was dismissed.