Wednesday, 6 July 2011

T 258/09 – It’s Contagious

I find this decision interesting because it shows that there are disclaimer-transmitted diseases (DTD): a disclaimer may transmit a deficiency such as a lack of clarity from the disclaimed prior art to the claim comprising the disclaimer.

The appeal was directed against the decision of the Opposition Division to revoke the patent.

Claim 1 before the Board read (in English translation):
The use of an adhesive tape having a tape-like backing of non-woven material, which is coated on at least one side with an adhesive, the web being a staple fibre web which is mechanically consolidated or wet-laid, the staple fibre web being consolidated further by the addition of binders, for bandaging cable harnesses as used in particular in the automotive industry, wherein the binders are not melt-blown fibres (Schmelzfasern) if their fraction in the fibres of the staple fibre web is between 2 and 50%. (the underlining marks the additions with respect to claim 1 as filed)
In dealing with the main request on file, the Board raises a clarity issue:

*** Translated from the German ***

[2.1] Claim 1 of the main request differs from claim 1 as granted in that it contains a disclaimer of subject-matter disclosed in D4.

[2.2] According to decision G 1/03 [headnote II.1] a disclaimer that has not been disclosed in the application as filed can be allowable if it serves to restore novelty by delimiting the claim against state of the art under A 54(3) and (4) EPC 1973. The disclaimer must meet the requirements of clarity and conciseness of A 84 (see G 1/03 [headnote II.4]).

[2.3] In the present case the disclaimer requires that the “the binders are not melt-blown fibres if their fraction in the fibres of the staple fibre web is between 2 and 50%”. The content of the melt-blown fibres is given in “%”. The [opponent] rightly criticizes that this indication as such does not disclose whether weight percent or volume percent are meant. It is not disputed that D4 does not provide any information on this indication.

[2.4] The [patent proprietor] expressed the opinion that it was usual in the field to use weight percent and that, therefore, the skilled person would a priori suppose that the percentages in D4 and, consequently, in claim 1, were weight percent. It also pointed out that weight percents were used in the opposed patent […].

[2.5] However, this argument does not persuade the Board. There is no indication in D4 that the indication “%” referred to weight percents. Statements in the opposed patent cannot be used for interpreting the disclaimer that has its origin in D4. Moreover, the claims have to be clear to the skilled person using his common general knowledge, so that he does not have to consult the description of the patent under consideration when interpreting the claim. Therefore, the argument of the [patent proprietor] based on the description cannot succeed.

[2.6] Moreover, the disclaimer also lacks clarity because, according to paragraph [0025] of the patent, additives such UV stabilizers or flame retardants can be added to the backing of non-woven material. However, the disclaimer does not disclose whether the fraction of the melt-blown fibres in the fibres of the staple fibre web has to be calculated before or after a possible addition of additives.

[2.7] It follows from the above that the disclaimer of claim 1 is not clear. Therefore, claim 1 cannot be granted.

If my understanding is correct, you cannot disclaim an unclear teaching. Either you disclaim it, unclear as it is, and the disclaimer will contaminate the claim. Or you make the disclaimer clear, but then it does not fit the prior art any more, and the disclaimer will not comply with the requirements of G 1/03. Either way, trouble ahead.

One more reason to avoid disclaimers whenever you can.

To download the whole decision (in German), click here.

The file wrapper can be found here.