T 0510/13 - Late found document and search strategy

Key points

• In this opposition appeal, the opponent filed a further prior art document. The opponent gave as reason for admitting the document, that the document "could not be found earlier despite an extensive search conducted in preparation of the opposition against the patent in suit". In order to prove this, the appellant disclosed its search strategy.
• The Board does not accept the argument. "The board observes that the search strategy carried out by the appellant, [] was based exclusively on the combination of keywords that were introduced for search in the fields of: title, abstract and claims in the databases DEPATISnet and Espacenet. Such a strategy however, suffers from several deficiencies. Firstly, it relies on keywords in databases that do not provide any control of keywords. Secondly, the keywords were not searched in the full documents but only in their title, abstract and claims. Thirdly, the use of synonyms and truncations was apparently not contemplated. And lastly, the appellant did not perform any alternative search strategy independent from keywords, e.g. using patent classification symbols, in order to compensate the limitations of a strategy based exclusively on keywords." 
• Clearly, the Board members know how to search!

EPO T 0510/13 -  link

Reasons for the Decision

3.1 Reasons for late filing document (15)

According to the appellant, document (15) could not be found earlier despite an extensive search conducted in preparation of the opposition against the patent in suit. In order to prove this, the appellant disclosed its search strategy and submitted that even carrying out the search retroactively with the knowledge of document (15), it was very difficult to find the document (see letter dated 24 January 2014, page 2). As an additional hint at the difficulty in finding document (15), the appellant noted that the document had not been cited in the international search report.

The board observes that the search strategy carried out by the appellant, as outlined in its letter dated 24 January 2014, was based exclusively on the combination of keywords that were introduced for search in the fields of: title, abstract and claims in the databases DEPATISnet and Espacenet. Such a strategy however, suffers from several deficiencies. Firstly, it relies on keywords in databases that do not provide any control of keywords. Secondly, the keywords were not searched in the full documents but only in their title, abstract and claims. Thirdly, the use of synonyms and truncations was apparently not contemplated. And lastly, the appellant did not perform any alternative search strategy independent from keywords, e.g. using patent classification symbols, in order to compensate the limitations of a strategy based exclusively on keywords. For this reason, the board is not convinced that the appellant carried out a comprehensive search and that document (15) could not have been found. In addition, the appellant's remark that document (15) was not cited in the international search report does not prove that the document could not be found. This could simply mean that the International Searching Authority did not consider document (15) to be relevant.

It cannot therefore be concluded that document (15) could not have been filed in opposition.