Inventions involving programs for computers can be protected in different forms of a "computer-implemented invention", an expression intended to cover claims which involve computers, computer networks or other programmable apparatus whereby prima facie one or more of the features of the claimed invention are realised by means of a program or programs. Such claims directed at computer-implemented inventions may e.g. take the form of a method of operating said apparatus, the apparatus set up to execute the method, or, following T 1173/97, the computer program itself as well as the physical media carrying the program (see T 424/03), i.e. computer program product claims, such as "data carrier", "storage medium", "computer readable medium" or "signal" forms described in F-IV, 3.9 and sub-sections.
The category of a claim directed to a computer-implemented method is distinguished from that of a claim directed to a computer program corresponding to that method (T 424/03 and G 3/08). Such claims therefore have to be examined separately.
The basic patentability considerations in respect of claims for computer programs are in principle the same as for other subject-matter. While "programs for computers" are included among the items listed in Art. 52(2), if the claimed subject-matter has a technical character it is not excluded from patentability by the provisions of Art. 52(2) and Art. 52(3).
Technical character should be assessed without regard to the prior art (see T 1173/97, confirmed by G 3/08). Features of the computer program itself (see T 1173/97) as well as the presence of a device defined in the claim (see T 424/03 and T 258/03) may potentially lend technical character to the claimed subject-matter as explained below. In particular in embedded systems, a data processing operation implemented by means of a computer program can equally be implemented by means of special circuits (e.g. by field-programmable gate arrays).
A computer program claimed by itself is not excluded from patentability if it is capable of bringing about, when running on or loaded into a computer, a further technical effect going beyond the "normal" physical interactions between the program (software) and the computer (hardware) on which it is run (T 1173/97 and G 3/08). The normal physical effects of the execution of a program, e.g. electrical currents, are not in themselves sufficient to lend a computer program technical character, and a further technical effect is needed. The further technical effect may be known in the prior art.
Likewise, although it may be said that all computer programming involves technical considerations since it is concerned with defining a method which can be carried out by a machine, that in itself is not enough to demonstrate that the program which results from the programming has technical character; the programmer must have had technical considerations beyond "merely" finding a computer algorithm to carry out some procedure (G 3/08).
A further technical effect which lends technical character to a computer program may be found e.g. in the control of an industrial process or in the internal functioning of the computer itself or its interfaces under the influence of the program and could, for example, affect the efficiency or security of a process, the management of computer resources required or the rate of data transfer in a communication link. A computer program implementing a mathematical method that itself makes a technical contribution (see G‑II, 3.3) would also be considered to be capable of bringing about a further technical effect when it is run on a computer.
Whether a computer program can contribute to the technical character of the claimed subject-matter is frequently an issue separate and distinct from the technical character of the hardware components which may be defined in order to execute the computer program. When a computer program produces a further technical effect (T 1173/97), it is by itself considered technical and not excluded. In contrast, any claimed subject-matter defining or using technical means is an invention within the meaning of Art. 52(1) (see T 424/03 and T 258/03, and confirmed in G 3/08). This applies even if the technical means are commonly known; for example, the inclusion of a computer, a computer network, a readable medium carrying a program, etc. in a claim lends technical character to the claimed subject-matter.
If claimed subject-matter relating to a computer program does not have a technical character, it should be rejected under Art. 52(2) and Art. 52(3). If the subject-matter passes this test for technicality, the examiner should then proceed to the questions of novelty and inventive step (see G‑VI and G‑VII).
A patent may be granted on one of the different forms of a computer program product claim if all the requirements of the EPC are met; see in particular Art. 84, Art. 83, Art. 54 and Art. 56, and G‑III, 3 below. Such claims should not contain program listings, but should define all the features which assure patentability of the process which the program is intended to carry out when it is run (see F‑IV, 4.5.2, last sentence). Short excerpts from programs might be accepted in the description (see F‑II, 4.12).