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A recent EPO Board of Appeal decision has dismissed the common test for novelty of a subrange and has instead proposed that the so-called “gold standard” test should be used. Under the gold standard novelty test, a claimed subrange is considered novel simply if there is no direct and unambiguous disclosure of the claimed subrange – regardless of whether the subrange is “sufficiently far removed” from any range in the prior art.


Historically (pre-2019), a subrange was considered novel over the prior art if the following criteria were met (T198/84 and T279/89):

a) The selected subrange is narrower than the known range;
b) The selected subrange is sufficiently far removed from any specific examples disclosed in the prior art and from the end-points of the known range; and
c) The selected range is not an arbitrary specimen of the prior art, i.e. not a mere embodiment of the prior art, but another invention (purposive selection, new technical teaching).

Since 2019, the Guidelines have stated that only the first two criteria must be met for a subrange to be considered novel.

The Present Case

In the present case, the patentee appealed the Opposition Division’s decision to revoke the patent (EP3056283) for lack of novelty.

The patent relates to rotary atomizer for painting. The claim in question included the feature that “…air discharged through the first air holes is twisted… at an angle of 56 degrees or more and 59 degrees or less.” The cited prior art disclosed air discharged at a twist angle of 50 degrees to 60 degrees.

It was therefore necessary to decide whether the subrange of 56-59 degrees in the claim was novel over the broader range of 50-60 degrees in the prior art.

The Opposition Division applied the historic three step test noted above and found that the claim was not novel. During the appeal proceedings the parties both agreed that the third step of this test is no longer relevant.

Appeal Proceedings

Not only did the Board of Appeal disagree with the use of the third step of the historic novelty test, but they also rejected steps (a) and (b) of the existing novelty test. The Board stated that the terms “narrower” and “sufficiently far removed” were too broad and open to subjective interpretation and as such believe that the present test cannot provide “objective, solid and consistent criteria for establishing novelty of a selected sub-range”.

Instead, the Board believed that the “gold standard” novelty test should be used, asking what a skilled person would have directly and unambiguously, using common general knowledge, derived from the prior disclosure. The Board further noted that the various tests with respect to Art. 123(2) EPC for different types of amendment are intended only to provide an indication of whether an amendment meets the gold standard test, and should not lead to a different result. Therefore, the Board felt that the same should be true for novelty over cited prior art documents.

As such, the Board went on to consider whether the skilled person, using common general knowledge, would directly and unambiguously derive a claimed sub-range from a particular disclosed range in the prior art.

The Opponent argued that the skilled person would have directly and unambiguously have understand that the prior art anticipated values in the middle of the stated range. The Opponent further argued that the disclosure of less than 60 degrees in the prior art was a direct and unambiguous disclosure of 59 degrees, as the next possible and logical alternative.

The Board of Appeal disagreed and instead stated that according to Case Law of the BoA I.C.4.1, the boundaries of a range cannot anticipate a specific value in the range. The Board further considered that this principle applied even to values adjacent to the end points of the disclosed range. As such, the board considered there to be no direct and unambiguous disclosure of the claimed subrange, finding the subrange novel.

The Board further considered the claimed subrange to be associated with a technical effect and therefore found the claim inventive, rejecting the Opponent’s argument that the technical effect existed outside of the claimed subrange, since the prior art in question did not disclose the technical effect.

The opposition decision to reject the patent was therefore overturned.

Relevance to the Doctrine of Equivalents’

Questions have been raised (for example by IPKat) on how this decision makes sense in the context of the UK Doctrine of Equivalents.

In most cases it would be expected that a device with an angle of 60 degrees would be found to infringe a claim to a device with an angle of 59 degrees under the UK Doctrine of Equivalents. However, the present case has found a device with an angle of 59 degrees to be both novel and inventive over a device with an angle of 60 degrees. Time will tell how this inconsistency is resolved.

Our articles are for general information only. They should not be considered specific legal advice, which is available upon request. All information in our articles is considered to be accurate at the date of publishing.


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