In a recent EPO Board of Appeal decision, T 2517/11, the Board has reaffirmed that for a feature to be deemed disclosed in a document, it is not necessary for the feature to be readily apparent on reading the document only once. Furthermore, the skilled person does not need to have specific motivation to investigate the existence of a “hidden” technical feature in the prior art.

In the case in question, Orange had applied for a patent for a method of transform-based coding/decoding of digital signals. The Examining Division had refused the application on the ground of lack of inventive step under Article 56 EPC.

Orange appealed the decision of the Examining Division, arguing that one of the features of the prior art on which the Examining Division had based their objections could only be determined after mathematical analysis and not solely from reading the text of the disclosure. In particular, the appellant argued that the skilled person would not be motivated to investigate a so-called “hidden” feature of the prior art and hence it would not be obvious to develop the prior art in order to arrive at the claimed invention.

The appellant further submitted that the Examining Division had misinterpreted the disclosure of one of the prior-art documents. In particular, the Examining Division had taken the statement “if the analysis window is restricted to be symmetrical…” to be an explicit indication to the skilled person to consider both symmetrical and asymmetrical coding windows. However, the appellant argued that the context in which the statement was used made it clear that it was only intended as a simplifying condition to enable a mathematical calculation to be performed, and not a disclosure of the option of using asymmetrical analysis windows.

In its decision, the Board referred to Enlarged Board decision G 1/92, which set out that, in relation to Article 54(2) EPC, “it is the fact that direct and unambiguous access to some particular information is possible, which makes the latter available, whether or not there is any reason for looking for it”.

The Board held that this test for disclosure was also relevant in the case of the claimed method and reasoned that the fact that the Examining Division was able to prove the existence of the particular “hidden” technical feature by mathematical analysis was itself proof that the feature in question was accessible and hence met the test for having been made available.

Despite its first line of argument being unsuccessful, the appellant was able to convince the Board that the Examining Division had misinterpreted the disclosure in one of documents cited as prior art. Ultimately, the Board decided that the application did involve an inventive step and the decision of the Examining Division to refuse the application was overturned.

In summary, in T 2517/11, the Board has followed the precedent set in G 1/92 with regard to disclosure in the prior art, namely that it is irrelevant whether there is any motivation to look for a feature in the prior art when considering the question of whether or not said feature is disclosed.