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IP Information & News

31 January 2017

EPO discuss choice of closest prior art


The assessment of inventive step of a claimed invention is a key part of the patent prosecution process and the European Patent Office (EPO) are no different from any other office in attempting to assess inventive step using a rigorous legal test. The preferred legal test at the EPO is the often discussed problem solution approach.

Problem Solution Approach

There are three main stages of the problem solution approach, they can be summarised as:
- determining the closest prior art;
- establishing the objective technical problem solved by any features of the claimed invention that are not disclosed by the closest prior art; and
- considering whether or not the claimed invention is obvious over the closest prior art.

The consideration of the closest prior art is therefore fundamental to the correct application of the problem solution approach. The EPO have recently discussed the criteria against which the closest prior art should be chosen when applying the problem solution approach.

The EPO’s own Guidelines are quite clear about what the criteria should be in that it is set out that the closest prior should be that single reference which discloses the combination of features which constitutes the most promising starting point for a development leading to the invention.

According to the EPO Guidelines, the selection of the closest prior art is guided primarily by the consideration of whether the document in question is directed to a similar purpose or effect as the invention or at least the consideration of whether the document belongs to the same or a closely related technical field as the claimed invention. That is to say, according to the EPO, the closest prior art should provide a promising starting point for arriving at the invention and only against such a starting point can the inventive step of an invention really be tested.
The EPO therefore appears to take a sensible approach to this matter – but there is always real frustration, particularly in cases related to software, when the Examiner’s at the EPO seem to go against this sensible teaching by choosing a piece of prior art which appears to be entirely unrelated or have only a tenuous link to the invention.

In software cases it is not unknown for an Examiner to cite a “commonplace” data processing system against a claim as the closest prior art – this inevitably leads to conclusions about inventive step which are trite and trivial and do nothing other than prolong prosecution.

T 1379/11

In case T 1379/11 the Board of Appeal held that the closest prior art must be a realistic starting point which must be a logical choice for the skilled person if they are dealing with the kind of matter to which the invention relates. A copy of the decision can be found here.

As ever, the word “realistic” is open to interpretation and some may remark that the use of the term “realistic” is hardly a profound departure in view of the Guidelines the EPO have themselves provided – but in reading this decision, the reader will notice that it is the consideration of what is a “realistic” choice of closest prior art that changed the document the Board of Appeal used in their consideration of inventive step – although it did not overturn the decision under appeal.

Comment

The Board of Appeal have indicated that the choice of closest prior art should be a realistic starting point for arriving at the claimed invention – which must be a logical choice for the skilled person to consider if they are dealing with the kind of matter to which the invention relates.

The term “realistic” can be interpreted many ways but, using a dictionary definition, its meaning can be summarised as representing things in a way that is accurate and true to life. If this meaning is adopted then this decision is suggesting that the closest prior art should be one which the skilled person would consider in real life.

Whilst we are sure the EPO is not trying to give the skilled person too many human qualities, here they give to the skilled person the power to decide on what is a realistic starting point for solving a problem. This, in turn, logically provides the skilled person with the power to decide on what is not a realistic starting point for solving a problem.

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