Claims described in terms of their function, effect or purpose

In this article Patent attorney Fredrik Martinsen summarizes patent claims described in terms of their function, effect or purpose in European patent applications.

One of the central requirements to a European patent application is that of Art. 84 EPC, namely that “the claims shall define the matter for which protection is sought. They shall be clear and concise and be supported by the description”. One purpose of Art. 84 EPC is to ensure that the claims of a European patent application are defined in a sufficiently clear and concise manner such that there can be little or no doubt as to which scope of protection is obtained upon grant of a European patent. The wording of Art. 84 EPC does not in itself give any explicit guidance of how to construct an allowable claim, making it necessary to look to the implementing regulations, case law and Guidelines for Examination.

A further specification of Art. 84 EPC may be found in the implementing regulations under R. 43 (1) EPC, first sentence, which states that “the claims shall define the matter for which protection is sought in terms of the technical features of the invention”. The EPC in itself gives no strict definition of what is meant in R. 43 (1) EPC by “technical features of the invention”, but the EPO guidelines (F-IV, 2.1) imply, however, that the “technical features of the invention” may comprise features in the form of expressions of structural limitations, and features described in terms of its function. A feature described in terms of its function may according to the Guidelines for Examination (F-IV, 6.5) be referred to as a functional feature. Below follow a number of feature formulations where the feature is defined in terms of its function, effect or purpose.

“Means-plus-function” feature (general case):

A so-called means-plus-function feature may be used instead of a structural feature in a product claim when there exist several alternatives of structural features that obtain a desired technical effect. Instead of listing all the alternatives for said structural features, one may rather describe the feature functionally by introducing a means-plus-function feature in terms of the formulation “means for [function]” or equivalently “[function] means” (F-IV, 6.5 and F-IV, 4.13.2). A simple example of use of a means-plus-function feature is the use of “means for writing” or “writing means” instead of “pencil”, “pen”, “crayon” or similar. Note that any means suitable for performing said function in a prior art document will anticipate the means-plus-function feature. A pen will as an example anticipate writing means. Observe that the latter is necessarily the case because of the genus vs species rule (G-VI, 5), where a means-plus-function feature is normally described as a genus.

“Means-plus-function” feature (CII case):

A means-plus-function feature may be used in a computer implemented invention (CII) in order to claim an apparatus that is specifically adapted to carrying out a certain method or method step (F-IV, 3.9.1). A means-plus-function feature in a CII claim may be formulated in different ways, e.g. “means for carrying out …”, “a processor adapted to …”, “a processor configured to …”, “a computer configured to …” and so on. Whether to use a formulation such as «comprising means for», «adapted to», or «configured to» is in this context considered to be equivalent as meaning “specifically adapted to” and not merely meaning “suitable for” (T410/96). Important to remember is that the term “specifically adapted to” in the context of a CII-claim generally is interpreted as meaning “programmed to” (F-IV, 3.9.1), although interpretations such as “hardwired to” or similar are likely also acceptable interpretations. The stated interpretation of the term “specifically adapted to” entails that a computer configured to, i.e. a computer programmed to perform a certain method is not anticipated by a general unprogrammed computer merely suitable for performing the same method.

When is it allowed to use a “means-plus-function” feature?

Use of a “Means-plus-function” feature is generally allowable under the condition that a skilled person would have no difficulty in providing some means of performing the stated function without exercising inventive skill (F-IV, 2.1). The latter may for example either be explicitly supported by describing a plurality of different suitable means in the description or be self-evident if the examples of suitable means are obviously known to the skilled person. Use of a functional feature is on the other hand not simply made allowable by stating vaguely in the description that “other means are suitable” or that “the person skilled in the art will appreciate that other means are suitable”. A detailed description focusing solely on one specific type of means without indicating that other means may be suitable may give the impression that a skilled person would in fact have difficulty in providing alternative means without exercising inventive skill. Such a detailed description of one specific type may thus increase the probability of being met with an objection under Art. 84 EPC (see F-IV, 6.5).

“Product for …“ feature:

A claimed product may be limited by stating for which purpose the product is suitable (F-IV, 4.13.1), i.e. by including in the claim a phrasing such as “product for [purpose]”. The content of the bracket is often referred to as a “for-clause” and the word “for” shall here be interpreted as “suitable for”. The use of the word “for” may thus be used in order to limit the scope of a claim by implicitly imposing certain limitations on the product, i.e. limiting the scope of the claim to products suitable for a certain purpose. A known product in a prior art document will thus only anticipate said claimed product feature if the known product is in fact suitable for the stated use.

Note that there exist certain other special uses of the term “for …”, e.g. when claiming a first or further medical use of known products (G-VI, 7.1).

“Method for …” feature

A “product for [purpose]” feature differs from a “method for [purpose]” feature in that the latter in certain cases may be considered as a technical functional feature, and not merely an imposition of a limitation on the use of the method. A “method for [purpose]”-feature is interpreted as a technical functional feature if the stated purpose defines a specific application of the method not inherent or implied by the other steps of the method (F-IV, 4.13.3). The purpose may thus here be considered as one of the method steps of the claimed working method.

“Second entity” feature

A claim related to a product may be formulated such that it defines a first entity by reference to features of a second entity not described in said claim (F-IV, 4.14). This kind of definition may for example be used where the size and shape of the second entity is standardized, or where a skilled person would comprehend the resulting restriction of the scope of protection for the first entity (F-IV, 4.14.2). When relying on the latter when describing a relationship between entities in a claim it is important to choose an appropriate wording dependent on whether one or both entities is/are described in said claim. A claim relating to a single entity A should use wording such as “connectable”, “couplable”, etc. when describing its relationship with another entity B not described in the relevant claim. A claim describing both entities A and B should on the other hand use wording such a “connected”, “coupled” etc. (F-IV, 4.14.1). Other wordings, such as “configured to connect” or “adapted to couple” to the second entity etc. may alternatively be used as long as the skilled person would have little difficulty in inferring the resultant restriction of the scope of protection for the first entity (F-IV, 4.14.2). As a way of example, a device claim referring to two entities, part A and part B, where A is defined as “connectable to B” should be interpreted as meaning that A is “suitable for being connected” to B (T304/08).