Inventive Step - Is it Still Plausible?

The closest prior art is first established and then differences between this prior art and the claimed subject matter are identified. The next step is to determine the technical effect arising from such differences. This is a key step in the problem-and-solution approach and often determines how difficult the prosecution of the case will be.

Where there is no technical effect, the problem may be formulated as merely providing ‘an alternative’ to the prior art. Accordingly, the chances of successfully demonstrating an inventive step can be reduced. In contrast, where the technical effect is significant or unexpected, the problem to be solved and the solution are more likely to be found to be inventive.

This raises the question of the amount of evidence required in a patent application if one wants to rely on a particular technical effect. Some of the Examining Divisions at the EPO are starting to routinely question whether or not the claimed technical effect relied on by the applicant is plausible based on the patent application as filed. This has followed from a decision (T1329/04) where the plausibility of an alleged technical effect was raised. In this case, there was a substantiated reason to doubt the plausibility of the alleged technical effect and the patent was found to lack an inventive step.

An important question has been: should the initial burden of proof lie with the patentee to provide evidence that the technical effect is plausible in the patent application as filed? Thankfully, following two recent cases from the Boards of Appeal of the EPO (namely T0578/06 and T1642/07) the answer is perhaps not.

According to these decisions, the initial burden of proof to substantiate doubts about the plausibility of the alleged technical effect lies with the EPO1. In general, there is no requirement for the patent application to have experimental evidence of the claimed technical effects2. Thus, only when such doubts are substantiated can plausibility be raised3. Therefore, in some situations, it may be enough that the claimed technical effect is simply disclosed in the description of the patent application3. However, when doubts about the plausibility of the technical effect need to be substantiated, evidence of the technical effect in the patent application may be required.

Ideally experimental evidence showing a technical effect is already included in the patent application as filed. However, where this is not the case there may now be some hope from these two recent decisions that the earlier case (T1329/04) should be cited with care by EPO Examiners. If these two later decisions are followed, in many instances experimental data may be filed during prosecution of a European patent application to confirm the alleged technical effect. However, such data may only be admissible if there is no substantiated reason to doubt the plausibility of the alleged technical effect.

Useful links

Full text of decision T-0578/06
Full text of decision T-1642/07
Full text of decision T-1329/04