Negatively defined claim features need to be interpreted narrowly when examining novelty
When examining novelty, the normal rule of claim interpretation of reading a feature specified in a claim in its broadest technically meaningful sense corresponds to determining the broadest scope encompassed by the subject-matter being claimed according to a technically sensible reading. In the case of a feature defined in a positive manner, which imposes the presence of a specific element, this is effectively achieved by giving to the element in question its broadest technically sensible meaning. However, for a feature defined in a negative manner, which excludes the presence of a specific element, the broadest scope of the claim corresponds to the narrowest (i.e. most limited) technically sensible definition of the element to be excluded (EPO Board of Appeal 28/10/2022, T 1553/19).