6. Interpretation of claims
6.2. Meaning of "comprising (substantially)", "consisting (essentially) of", "containing"
In T 759/91 and T 522/91 the claims contained the expression "comprising substantially". The board was of the opinion that this term lacked clear, explicit boundaries and its scope needed interpretation. While in everyday language the word "comprise" might have both the meaning "include" or "comprehend" and "consist of", in drafting patent claims legal certainty normally required it to be interpreted by the broader meaning "include" or "comprehend". The word "substantially" imposed a restriction on the word "comprising" in the sense that "to a large extent only that is comprised which is specified". The boundaries of the term "comprising substantially" were therefore to be drawn where the essential characteristics of the specified subject-matter ceased. The scope of the term "comprising substantially" was therefore interpreted as being identical to that of "consisting essentially of". However, in view of the unequivocal character of the words "consisting of" as compared to "comprising", the expression "consisting essentially of" was to be given preference. See also T 1730/09, T 274/16.
In T 405/00 the board considered that, according to the language conventional for patent claims in the field of chemistry, the wording "composition comprising a persalt" defined exclusively the mandatory presence of at least one of the specific chemical compounds belonging to the group of persalts.
In T 1023/02 the board stated that a claim using "comprising" language should generally not be construed as covering subject-matter which included further steps of a nature that would manifestly counteract the specified technical purpose of the step(s) recited in the claim.
In T 1599/06 the board likewise had to interpret the term "comprising". It emphasised that the meaning of terms in a patent claim has to be determined from the point of view of the skilled person, who reads the claim in the context of the application and against the background of their common general knowledge. The claim was directed to a vaccinating agent comprising at least one specific purified and isolated protein of Mycobacterium tuberculosis. The examining division had interpreted the term "comprising" broadly and held that the claimed subject-matter lacked novelty in relation to a partially purified protein fraction which, in their view, contained inter alia the specified proteins. In the board's view, however, the skilled person would derive from the application as a whole the information that the specific characteristic of the vaccinating agents according to the invention was their generation from isolated and purified Mycobacterium tuberculosis proteins. Therefore, the skilled person would have considered that the definition in claim 1 covered vaccinating agents that, firstly, were constituted from isolated and purified proteins as mentioned in the claims and, secondly, contained those proteins as their main constituents.
In T 1771/06 a claim specifically referred with closed language to the characterising part (GBSS gene fragment in the antisense direction) of the gene construct and, in an attempt to generalise, left open other structural elements necessary to operate the system ("comprising a fragment ... which codes for ...., said fragment consisting of a nucleotide sequence selected from ... SEQ ID No: ..."). According to the board this was not an unusual claim formulation. The board did not accept the appellant's argument that the scope of the claim extended to gene constructs which comprised any DNA in addition to the GBSS gene fragments. The skilled person would certainly take into account the fact that the gene construct was made for the purpose of introducing the GBSS DNA fragment into the potato cells and integrating it into the genome. Accordingly, the gene construct would be thought to contain all necessary DNA elements for these steps to take place.
In T 390/08 the board held that the definition of a composition as "consisting of" compulsory and optional components met the requirements of Art. 84 EPC, as such a composition defined a "closed" composition from which elements other than those mentioned were excluded. See also T 1190/01, T 1998/07.
In T 2027/13 the claimed composition was defined by an open formulation (in view of the word "comprising"), which already implied the presence not only of the optional excipients, but also of any additional pharmaceutically acceptable components (including impurities) and even of further release controlling agents, and the expression "consisting essentially of", which referred to a single ingredient of the composition. As the usual reading of this expression did not make sense in the case in hand, the skilled person reading the claim was at a loss as to the possible limitation introduced by the expression.
In T 2103/22 the claim was directed to "[…] a layer of a polyester resin which comprises an ethylene terephthalate unit […], characterised in that said polyester resin is a blended polyester resin which is a blend of a lowly crystalline polyester resin and a highly crystalline polyester resin at a weight ratio of 90:10 to 10:90 […]".The board stated that, although it was correct that the normal rule of claim construction was that the terms used in a claim should be given their broadest technically sensible meaning, the literal reading of this passage defined that "said polyester resin" consisted of the lowly crystalline and highly crystalline polyester resins further defined in the claim, in the given weight ratio, i.e. it excluded the presence of any other components other than the ones specifically defined. As the polyester resin specified in the term "a layer of a polyester resin" was identical to the "said polyester resin", the board concluded that it consisted of a blend of only the lowly and highly crystalline polyester resins.
In decision T 711/90 the board confirmed the assumption in the case law that the substitution of the term "consists of" for "contains" in a claim raised the question of clarity of the claim. When, as in the claim in question, the glass consisted of components denoted (i), (ii) and (iii), the presence of any additional component was excluded and, therefore, the proportions of the components (i), (ii) and (iii) expressed in percentages should have added up to 100 mole % for each claimed composition.
Regarding Art. 123(2) EPC, see chapter II.E.1.15. "Comprises", "consists of", "consists essentially of", "contains".
- T 0583/23
In T 583/23 the parties agreed that claim 1 related to a closed composition, i.e. a smoke condensate that did not include other components than those stated in the claim.
The board noted that claim construction, namely the meaning that a skilled person would give to the wording of a claim, was a question of law. In determining this, the board was not bound by the parties' views on the matter. The smoke condensate composition defined in claim 1 was introduced by the term "comprising." Due to the open-ended nature of this formulation, the inclusion of additional ingredients was, in principle, not excluded. Moreover, the scope of claim 1 included smoke condensates having a low pH of between 2.0 and 3.5, which were a preferred embodiment in the patent. These smoke condensates must necessarily comprise acids. Likewise, claims 2 and 3 contained further limitations which were not in line with a "closed" interpretation of claim 1.
Citing T 107/14 and T 303/20, the respondent (opponent) had argued that claim 2 as granted was a "false dependent claim" because it altered the closed composition of an allegedly closed independent claim 1. The board disagreed. As suggested in T 107/14, whether a particular amendment extended beyond the content of the application as originally filed must be assessed based on the information that is clearly and unambiguously disclosed in the entire application as originally filed, i.e. on the merits of the specific case. The same holds true for the interpretation of a specific claim and the question of whether it is a dependent claim or not.
According to the board, the indication "and the rest water" in claim 1 did not rule out the presence of further components in the smoke condensates, as long as water complemented the composition to 100 wt%. Such an interpretation of claim 1 was technically not nonsensical. By contrast, it was in line with e.g. claims 2 and 3 when interpreted as "truly dependent claims", and it led to a scenario which was not at variance with the teaching of the patent itself.
For these reasons, the board construed claim 1 as encompassing smoke condensates which could comprise other components than those explicitly specified in the claim ("open claim formulation"), such as, undoubtedly, acids.