Whilst machine translations are no doubt useful in many circumstances and can save a patent applicant time and money, they are often not accurate enough to determine the exact relevance of a prior art document for a patent application.

T1343/12, a recent decision from the EPO concerns the use of a machine translation of a Japanese reference, which was cited for inventive step.  The claims indicated that a surfactant was present in an oil-based composition in an amount of 10-30% ("the quantity of the non-ionic surfactant (B) is in the range of 10 to 30% by mass of the oil for dust adsorption").  The machine translation of the prior art document contained a seemingly relevant sentence which stated:

"The amount of the surface-active agent used besides the above of below 10 mass % is 0.1 to 8 mass % still more preferably preferably [sic] among the oils of this invention."

The board indicated that this disclosure was ambiguous and could mean up to 10%, more preferably 0.1% to 8%, or could mean 10% of one surfactant component plus 0.1% to 8% of another surfactant, i.e. giving a total of up to 18%.  Whilst the first meaning could arguably teach away from using higher amounts of surfactant, e.g. as claimed, the second meaning would provide a teaching which would fall within the claimed range. 

In view of the ambiguity, the Board was unable to make a decision regarding this prior art document and the case was remitted back to the Examining Division for reconsideration of inventive step based on a certified translation of the document. 

Thus in some instances, machine translations of foreign language prior art documents may not be sufficient for use at the EPO.  Whilst there was no indication in the decision regarding whether the EPO or the applicant should obtain and pay for the certified translation, one would assume that this burden would lie with the EPO who cited the document in the first place.  However, the file wrapper for the application indicates that the EPO had already requested the provision of a translation of 3 cited Japanese documents in the search opinion (where the applicant responded by filing machine translations).  As the burden of supplying certified translations would be high for either an applicant or the EPO, it will be interesting to see how this issue pans out.