European patents cannot be opposed on the ground that the claims are unclear. In this case, the opponents argued that unclear features of the claims resulted in the claims being excessively broad and therefore insufficient. However, contrary to the Opponents’ argument that the unclear features must be considered as a whole, the Board of Appeal considered that for a fair and objective approach, each issue must be considered on a one-by-one basis.

EPO Decision T1285/15 relates to an appeal from an Opposition Decision to maintain (in amended form) European Patent No. EP1567358 owned by De La Rue International Limited.

The patent relates to security devices, for example those used to verify the authenticity of documents. The security device comprises two different materials which appear to have the same colour when viewed under “normal”, visible light but have different colours when viewed under UV light.

Claim 1 of the patent as granted reads as follows:

  1. A security device comprising two or more regions, each region containing a material or combination of materials wherein the two or more regions exhibit substantially the same visible colour under first viewing conditions comprising visible light and different visible colours under second viewing conditions, the second viewing conditions comprising a combination of […]
  2. d) [sic] visible light and
  3. e) [sic] light of substantially any UV wavelength in the range 235-380nm.

Three oppositions were filed based on various grounds, but the patent was ultimately held to be valid following amendments by the proprietor.

On appeal, one of the issues raised was whether the claims of the patent were sufficient. The Opponents considered numerous features of the claims to lack clarity, for example:

– The portion of UV light comprised in the first and second viewing conditions were not defined and therefore the first and second viewing conditions were indistinguishable (the definition of the first viewing condition did not exclude the presence of the UV light specified for the second viewing condition).

– The terms “the same” and “different colours” are functional and subjective and there is no objective method for determining this (e.g. the wavelengths of the visible light). Two different observers do not see colours in the same way and hence the skilled person has no way of differentiating different colours.

Although lack of clarity is not a ground of opposition, the Opponents/Appellants argued that as a result of the lack of clarity of the claims, the skilled person would not be able to work the invention over the scope of the claims and therefore the claims were insufficient.

In addition, they argued that the issues should not be considered one-by-one, but instead in combination. In their view, the claims covered an infinite number of colours and colour combinations without offering the skilled person enough guidance on how to produce such a wide range of devices (only a single example was given in the patent).

The Technical Board of Appeal considered each of the clarity issues one-by-one and held that each was clear in the content of the present patent.

The Board of Appeal rejected the Opponents/Appellants “holistic view” argument and stated that there is no other way for the Board to tackle multiple objections other than by breaking the sum of the objections into distinct aspects. The Board considered that this is what the skilled person would have done when faced with difficulties in working the invention.

It was therefore ultimately concluded that the approach taken by the Opposition Division to treat each issue separately was not flawed and that a more holistic approach would have had to have been based on an overall impression and would not have been objective.

If this decision is followed in other cases, then it is likely to become more difficult for opponents to run sufficiency attacks based on allegedly unclear claim features.

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 Our news articles are for general information only. They should not be considered specific legal advice, which is available on request.


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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