In Telefonaktiebolaget LM Ericsson T 1688/08, a technical appeals board of the European Patent Office disapproved of the Examining Division’s approach in assuming that the skilled person would look only at the English abstract and drawings of a foreign language prior art document when considering obviousness in relation to a patent application.


Telefonaktiebolaget LM Ericsson applied for European Patent No. 1010024 on 25 June 1997 for an optical element of an optical fibre. The optical element utilises multimode interference in an optical fibre with a cylindrical or tubular core. The idea behind the invention is to provide for optical elements that utilise multimode interference and can be manufactured and constructed in a simple way. Such an optical element can be used as a filter, sensor, switch or coupler.

The application was refused initially on 27 March 2008— following oral proceedings on 21 January 2008—due to a lack of inventive step. One of the documents cited by the Examining Division as being closest prior art was a Japanese language patent application. The Examining Division held that a skilled person faced with the problem of determining how the device disclosed in this document worked would either seek a translation or make a comparison to similar devices. The Examining Division considered such a document disclosing a similar device in order to understand some technical aspects of the Japanese language patent application. On 5 June 2008 Telefonaktiebolaget appealed against the refusal.


On 17 July 2012, the board held that decision under appeal should be set aside and that the patent should be granted. The board criticised the Examining Division’s approach in relation to the interpretation of the Japanese patent document. The Examining Division assumed that the skilled person did not understand Japanese and sought to interpret the document by reference to the teachings of a separate document. The board stated that this methodology was not credible because the language of a patent should not be the decisive factor as to whether or not the skilled person considers the technical content of the document. Otherwise, skilled persons would be differentiated according to the language or languages they speak. This would be contrary to the principle that inventive step is assessed objectively. Further, the board was not convinced that the skilled person would believe that another document, having some features not dissimilar to those of the invention disclosed in the Japanese patent document, would actually correspond to the disclosure of the subject matter claimed in the Japanese patent document.


This decision suggests that if a translation is not provided, one should be obtained, in order to determine the invention disclosed in a foreign language prior art document. While it may be helpful to draw parallels between similar inventions, an analysis based on similarities is no substitute for actual knowledge.