In case T 0555/18, the opponent appealed the decision to reject the opposition against EP2117839 B1. The Appellant [OA] requested to revoke the patent on all 3 grounds of opposition.
The Respondent (Proprietor) [RP] filed 10 Auxiliary Requests [AR], requested that the patent be maintained as granted or based on one of the ARs. Claim 1 of all ARs was directed to a film and comprised the following feature:
‘’FTIR Transmission Absorbance Ratio:
A1199/A1170 ≤ 1.65,
wherein A1199 is determined by integrating a peak area between 1223.6 cm-1 and 1186.0 cm-1 with a baseline made by connecting points on the curve at 1223.6 cm-1 and 1186.0 cm-1 with a straight line, and wherein A1170 is determined by integrating a peak area between 1186.0 cm-1 and 1152.5 cm-1 with a baseline made by connecting points on the curve at 1186.0 cm-1 and 1152.5 cm-1 with a straight line,….’’
The Board found when assessing the closest prior art, that the only feature differentiating claim 1 from the closest prior art was the FTIR Transmission Absorbance Ratio of 1.65 or lower. Since the invention defined in claim 1 provided none of the alleged technical effects set out in the patent, the problem to be solved was formulated as the provision of an alternative film to the one known from the closest prior art.
To address the question of obviousness, the Board further clarified the substantial meaning of the FTIR ratio and whether the ratio can be regarded as an unusual parameter.
According to the patent, the FTIR ratio would represent a proxy for the ratio between the degree of crystallinity of a semi-crystalline polyamide comprised in a layer of the claimed film, and the total polyamide content. Thus, the defined low values of the FTIR ratio were interpreted as implying that the film had a large content of polyamide with a relatively low degree of crystallinity. RP further argued by referring to a prior art handbook, that the parameter was not unusual.
The Board did not concur with this position and stated that the concept of "unusual parameters" did not necessarily imply that the parameter was unknown, but rather that it was uncommon in the sense that it was not generally used in the specific form as proposed in the claims within the underlying technical field. In the case at hand, the Board found the FTIR ratio was not commonly used in the field of the invention, and, additionally, that the parameters used in the formula of the claims (absorbance values, and wavenumbers) were not the same as in the prior art. Based on this reasoning, the Board concluded that the FTIR ratio was an unusual parameter.
The Board concluded that when the only feature distinguishing a claim from the closest prior art is a range of an unusual parameter, a similar approach to that proposed in inter-partes cases T 0131/03 and T 0740/01 should be applied to decide on the question of obviousness. In both of these cases, the burden of proof was shifted to the proprietor and there was a strong presumption that the unusual parameter was inherently disclosed in the prior art. The Board further set out: ‘’once it has been established that it would be obvious for the skilled person to solve the underlying technical problem in ways that can be presumed to inherently lead to values within or close to the claimed range, it is the proprietor who should carry the burden of proof to demonstrate that implementing such solutions would not lead to the claimed parametrical range.’’
The Board considered this approach justified, because it would be unequitable for a party to benefit from the uncertainties created by its decision to define the invention in terms of an unusual parameter.
RP set out that even if the teachings in the prior led to products having the same type/amount of a polymer and shrink levels as the invention, this did not necessarily imply that the FTIR ratio (i.e., the crystallinity to polyamide amount ratio) fell within the claimed range. RP argued that the shrink level could have resulted from other steps. Since there was no hint in the prior art that would lead the skilled person to adjust the crystallinity of the polymer in the prior art such that the FTIR ratio would fall within the claimed range, the subject-matter of claim 1 was not obvious in view of this document.
The Board ruled that it had to be the proprietor who carries the burden of proof to demonstrate that the films which would be obtained in an obvious way in view of the teachings in the prior art would fall outside the scope of claim 1. This burden was not discharged by RP because no evidence was provided that the film according to the prior art would have a FTIR ratio outside the claimed range.
The Board found that the arguments that it was ‘’not impossible for the films in the prior art to have an FTIR ratio falling outside the range of the invention’’ or that there was ‘’no definitive proof that the films in the prior art have a crystallinity low enough to render claim 1 obvious’’, in fact, even appeared to be an attempt by the proprietor to benefit from the uncertainties caused by its decision to draft the invention in terms of an unusual parameter. The latter was precisely what the Board intended to avoid by shifting the burden of proof to RP or by giving the OA the benefit of the doubt. The Board therefore concluded that the solution proposed in claim 1 of all ARs was obvious in view of the prior art.
The Board decided that the subject matter of claim 1 of all Request was obvious in view of the prior art and that none of the requests met the requirements of the EPC. The decision under appeal was set aside and the patent was revoked.