9.7. Substitution of materials – analogous use

In T 21/81 (OJ 1983, 15) the board held that it had to be considered as forming part of their normal activities for a skilled person to select, from the materials known to them as suitable for a certain purpose, the one which was the most appropriate. In T 324/94 the board held that the skilled person should therefore be at liberty, within the constraints of standard technical progress, to use alternative means known by them to have the same effect. In T 410/92 the board concluded that the skilled person who encountered known problems when using newly developed materials would not be deterred from using them in order to achieve specific, desired improvements, particularly since the means of overcoming such problems could be derived from the prior art.

The Headnote in T 192/82 (OJ 1984, 415) reads as follows: If an article is known as a combination or mixture of components fulfilling known functions, the generation and application of an improved novel component for the same purpose may be patentable as such and also as an improved article incorporating the same. If the component in question forms, on the other hand, part of the state of the art together with its relevant properties, the incorporation thereof in the same article will be obvious in view of its predictable beneficial effect ("analogous substitution").

In this regard the board in T 130/89 (OJ 1991, 514) held that the use of a known material in a combination on the basis of its known properties and in a known manner to obtain a known effect was not normally inventive ("similar use"). Exceptions to this principle might be allowed in special cases, e.g. where a selection brought unexpected advantages, a known prejudice was overcome or unforeseen difficulties were encountered, such as the need to alter another component (see also T 1216/05, T 330/07, T 422/09).

Following these decisions, the board summarised as follows in T 213/87; in the absence of any unexpected effect, the mere substitution of an element by another known for its relevant properties to provide that known effect could not be regarded as patentable.