A composition which is specified in a claim as comprising a component in an amount which is defined by a numerical range of values is subject to an implicit proviso excluding the presence of that component in an amount outside of that range. An amendment restricting the breadth of that component, for instance by narrowing down a generic class or a list of chemical compounds defining that component, has the consequence of limiting the scope of this implicit proviso. However, a composition which is defined as comprising the components indicated in the claim is open to the presence of any further components, unless otherwise specified. Therefore in a claim directed to such an openly defined composition, the restriction of the breadth of a component present therein may have the effect of broadening the scope of protection of that claim, with the consequence that in opposition/appeal proceedings such amended claim may extend the protection conferred by the granted patent (Art. 123(3)) (see T 2017/07 and T 287/11). Restricting the breadth of the component means that certain materials are no longer explicitly limited by the claim and therefore can be present in amounts which were excluded from the granted claim.
Date retrieved: 30 December 2018