CASELAW - reviews of EPO Boards of Appeal decisions

T 2100/18 – Why is it necessary for a BA to refer to US case law? How do ranges have to be interpreted?

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Brief outline of the procedure

The application was refused for lack of IS. An appeal followed.

In a communication in preparation for the oral proceedings, objections under Art 56, 84 and 123(2) and R 49(10) were raised by the board.

Following the communication of the board, the applicant filed a new request which was admitted under Art 13(2) RPBA20 by the board.

The board remitted to the ED with the order to grant a patent on the basis of the claims according to the MR filed as AR 4 and possibly a description to be adapted to these claims.

The original clarity objection

In the communication under Art 15(1) RPBA20, the board was of the preliminary opinion that the feature of an “acidified additive solution having a pH of between 5.5 and 7.0” in claim 1 of the previous main request was unclear.

More specifically, the term “acidified” meant that the solution was made acidic and an acidified additive solution could not have a pH of 7.0.

In addition, the board referred to a US decision in order to support his objection.

According to the decision “Athletic Alternatives, Inc. v. Prince Manufacturing, Inc.,” 73 F.3d 1573 (Fed. Cir. 1996), it was not clear whether a range using the term “betweenincludes the limit values of this range, cf. Point 4.2 of the reasons.

The later position of the board

The board eventually held that in the present case, it does not need to be specified whether or not the term “between” is clear, since this term is not contained in claim 1 in isolation, but in a specific context, namely combined with the statement that the additive solution is acidified.

Hence, at least in the specific context of the present case, there can be no doubt that the value of 7.0, which implies a neutral rather than an acidic pH, is excluded, cf. point 4.3 of the reasons.

Claim 1 of the main request therefore met the requirements of Art 84.

The question of ranges

It appears established case law that in case of a range of values, the end values of a closed range are part of the original disclosure, whereas in an open range, the end value is not part of the disclosure.  

For example, in T 1990/10, relying on T 2/81, the board held that, on the one hand, a closed range comprised the end values, e.g. 30-35°C, which clearly means “between 30°C and 35°C”, the end values of 30°C and 35°C are part of the disclosure.

On the hand, in the open range below 35°C, the value 35°C is not part of the range.

When stating in the claim at stake that the feature “acidified additive solution having a pH of between 5.5 and 7.0”, it has to be concluded that the value pH 7.0 is part of the range.


Why was it necessary for a board to refer to a US decision when dealing with the feature of an “acidified additive solution having a pH of between 5.5 and 7.0”?

When looking at the case law about ranges it is manifest that the range “between 5.5 and 7.0” comprises the end value of 7.0.

The claim can thus be considered unclear as it implies a neutral rather than an acidic pH.

A clear claim could have looked like this: an “acidified additive solution having a pH of between 5.5 and less than 7.0”. In such a formulation, the value of pH 7.0 is clearly excluded and that of pH 5.5 is included.  

What do you think?  

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5 replies on “T 2100/18 – Why is it necessary for a BA to refer to US case law? How do ranges have to be interpreted?”

One of the first things I was taught, as a new trainee patent attorney in London, years before the EPO opened, was the importance of using words with precision, using the example of delineating ranges. If you want in your claim positively to include the end values, then write “from X to Y”. Conversely, if you want positively to exclude the end values, write “between X and Y”. How simple things were, back then. Those were the rules, and any competent patent agent knew them. Things are more complicated now, eh Daniel?


Dear Max Drei,

Things are not really more complicated.
What was valid in the UK might not be valid in Europe and vice-versa.

In my humble opinion “between”b is unclear as it is not clear whether the end values are comprised or not.
What I can deduce from the way some decisions have interpreted ranges is:
– when a range is closed, the end values are comprised in the range. In the range 10-100, 10 and 100 are comprised.
– in case of an open range, the end values are not comprised. In 30 to less than 100, 30 is comprised in the range, 100 is not.

Exactly, The term “between” is unclear, in that it is ambiguous whether the end point of the stated range is covered or not. But as we both know, sometimes a claim drafter (perhaps in the USA) intends that ambiguity. Ideally, those who deliberately write an ambiguous claim will get “hoist with their own petard”. When assessing validity, the broader meaning is taken but when the claim owner brings an infringement action the claim is positively held NOT to include the end of range numbers.

I’m interested, Daniel, that you categorize such a claim as exhibiting an “open” range. For me it is “closed” but with an unclear point of closure. For me, an “open” range is one for which one (or both) end points are unstated. Thus, for example, “A cloud with a volume of at least one cubic meter”. How big can it get? It covers a cloud in which you can hide, say, Planet Earth.

Open ranges in claims are open to a lot more objections than a claim that says “between”. I daresay you agree.

PS. I suspect that “petard” is a French word. I wonder then, do you speak in France about being hoist with your own petard, or was it only William Shakespeare who came to that idea?


I fully agree with the board; the claims must be read as a whole. The ordinary meaning of “between” is ambiguous and the use of the qualifier “acidified” provides a good reason to interpret “between” in the way that the board did. The case law on ranges is contrived and illogical. At the end of the day, what matters is how a reasonable person attempting to make technical sense of the claims would read them. The claims in this case can be interpreted in a sensible way without making artificial distinctions between the words “from” and “between”. It is strange that the board chose to refer to a US case when to my mind, the board’s decision is consistent with the approach described in the Case Law:
“According to the established case law, the skilled person should try, with synthetical propensity, i.e. building up rather than tearing down, to arrive at an interpretation of the claim which is technically sensible and takes into account the whole disclosure of the patent. The patent must be construed by a mind willing to understand, not a mind desirous of misunderstanding (see inter alia T 190/99, T 920/00, T 500/01, T 749/03, T 405/06, T 2480/11, T 2456/12, T 383/14, T 1477/15).
A considerable number of decisions held that the skilled person, when considering a claim, should rule out interpretations which are illogical or which do not make technical sense (see inter alia T 190/99, T 552/00, T 920/00, T 1023/02, T 749/03, T 859/03, T 1537/05, T 1204/06, T 681/15). Some decisions (T 1408/04, T 1582/08, T 493/09, T 5/14, T 2110/16) emphasised that this is understood to mean only that technically illogical interpretations should be excluded. A mind willing to understand did not require that a broad term needed to be interpreted more narrowly (even if, as in the case underlying T 1408/04, the narrower interpretation would refer to a structure which is very common, but not exclusive, in the technical field concerned).”


Dear Anonymous,

I am fully aware of the the fact that a claim has to be interpreted with the will to understand it and not to misunderstand it.

I can easily follow the board’s interpretation of the claim, but I am not sure that it is the only possible one.

That’s all I wanted to say.

What was disturbing was the reference to US case law by a BA of the EPO. This was actually the reason for my post.

The question of ranges was secondary to me.

In the present case, the formulation might be acceptable, but more generally I have my doubts. The doubts stem from the fact that “between” is as such unclear as it does not make clear whether the end values are disclosed or not.

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