IP Information & News

Is a numerical range novel if it overlaps with a previously disclosed numerical range?

The Court of Appeal considered this scenario in Jushi v OCV. To a certain extent, this judgment brings the UK approach to patentability of overlapping numerical ranges in line with the established approach at the European Patent Office (EPO). However, further clarification is still needed.

Background to the case

OCV’s patent related to glass fibres or “strands” for inclusion as reinforcement in other materials such as glass-reinforced plastic. The main claim was directed to a glass strand and recited the weight percentage ranges of various constituents of the strand, e.g. silicon dioxide (SiO2) at 58-63%, aluminium oxide (Al2O3) at 12-20% and so forth.

A prior art document in the same field also disclosed glass fibres — of which the percentage ranges of 12 constituents overlapped with the claimed ranges in the patent.

The patentee (OCV) acknowledged the same prior art document in its patent and included a comparative test between the claimed glass fibres and those of the prior art document, showing that the claimed selection of percentage ranges resulted in a glass strand with improved performance.

Jushi sought revocation of OCV’s patent on the basis that the patent claims were anticipated (lacked novelty) over the fibres disclosed in the prior art.

EPO approach to overlapping ranges

At the EPO, overlapping ranges are dealt with during examination by establishing whether a person skilled in the art would “seriously contemplate” applying the technical teaching of the prior art document in the range of overlap (T 26/85). Both the UK courts and EPO’s approach has been consistent, in that novelty is destroyed if the prior art discloses an example falling within the overlapping range.

However, at the EPO, for novelty to be acknowledged for an overlapping range there must also be a technical effect associated with the claimed range, i.e. the claimed range must not be an arbitrary selection. This test is akin to the test applied for “selection inventions”, i.e. the selection of narrower subject-matter from a broader disclosure.

The need to demonstrate a technical effect in order to establish novelty essentially links the assessment of novelty with the assessment of inventive step — and for this reason, the UK courts have been reluctant to follow the EPO’s approach.


The previous test used by UK courts when considering overlapping ranges was to establish whether the matter relied upon as prior art disclosed subject-matter which, if performed, would inevitably result in something that fell within the claims of the patent in suit.

However, the first instance judge considered that the EPO test of “serious contemplation” was a more appropriate test.

On appeal, the Court upheld the finding of novelty. In particular, the Court was not satisfied that the skilled person would seriously contemplate the production of glass fibres that incorporated each and every range of overlap that would be needed to arrive at a glass fibre falling within the scope of the claims. This was because a skilled person would expect small changes in constituent percentages to have a large impact on the properties of the resulting glass fibres, and therefore would not choose any combination of values from the prior art ranges.

However, unlike the EPO approach, the Court of Appeal did not explicitly contemplate the presence of a technical effect in the claimed percentage ranges in order to arrive at the finding of novelty. This is perhaps because a technical effect was implicit from the comparative data in the application.

The Court of Appeal also held (with a strikingly similar justification to the assessment of novelty) that in the absence of a reason to do so, the skilled person would be unlikely to vary the relative amounts of each constituent in the prior art due to the impact on the resulting properties. Therefore, the Court concluded that the skilled person would not deviate significantly from the examples disclosed in the prior art.

As a result, OCV’s patent was held to be valid.


This case helpfully brings the UK approach on assessing novelty of overlapping ranges in line with the EPO’s approach of considering “serious contemplation”. However, the Court did not provide any comment on if, or under what circumstances, the presence of a technical effect would need to be demonstrated in order to establish novelty in an overlapping range.

It is expected that the UK courts will now also follow the EPO’s approach with respect to demonstrating a technical effect in an overlapping range. However, we will need to wait for a further case to confirm this expectation.

If you would like to discuss the patentability of overlapping ranges, please get in touch with Dr Simon Mitchell at sjm@udl.co.uk.

You can find out more about patents and our services here.

Related articles

You may also be interested in these...



​The patent process — a materials perspective

Take a look at the different elements of a patent, with some advice for materials-based inventions.

Read more



How to define complex materials in patent applications

How can you provide a clear definition of a material for a patent that is near impossible to define?

Read more



When is further processing at the EPO not available?

Are you in danger of missing a deadline at the EPO?

Read more

Website by Extreme