In common with many patent offices around the world, some inventions that are implemented in software may be patented before the EPO.

In this chapter, we explore software patentability covering why only some software inventions are patentable before the EPO, the requirements for an invention to be patentable and how patent practice before the EPO with respect to software inventions may evolve in the future.


The European Patent Convention (EPC) is the statute under which the EPO operates to determine the grant of European patents. The EPC defines that European patents will be granted in all fields of technology, but excludes a specific list of subject matter from being considered as inventions, which includes, inter alia, mathematical methods, methods for doing business and computer programs. These exceptions from patentability have been described as relating to activities that do not aim at any direct technical result but rather are of an abstract and intellectual character. The exceptions from patentability are, however, limited in scope in that they relate only to "such subject-matter or activities as such".

Technical character is a requirement of an invention under the EPC, which was previously only implicitly required but is now explicitly mentioned in Article 52(1). To determine the patentability of an invention, particularly one that may relate to computer software, the EPO applies a two-hurdle approach. The first hurdle is to assess whether a claim relates to a non-invention falling within one or more of the list of excluded subject matters. The second hurdle involves consideration of whether the remaining requirements for a patentable invention are met, particularly that the invention is novel and has an inventive step. Therefore, only claimed subject matter having a technical character can be considered an invention, and to be a patentable invention it must also be novel and have an inventive step.

Alice test

Here we see a parallel with US patent practice where there are also two patent eligibility hurdles to overcome, known as the 'Alice test'. Here, the first hurdle is a test of whether the claimed invention is directed to a patent ineligible concept. A patent ineligible concept is one that is considered an abstract idea, as determined by the US Supreme Court. If so, to then avoid rejection, there must be some elements of the claim relating to an inventive concept sufficient to 'transform' the abstract idea into one relating to a patent-eligible invention. The inventive concept must be more than a recitation of a well-understood, routine, conventional activity. On the face of it, therefore, merely reciting in a claim generic computer features or activities (eg, processing or receiving) will be insufficient to transform the claim from one that is considered abstract to patent-eligible subject-matter. In comparison with the EPO's two tests, the first differs between EPO and US practice in that under EPO practice it is considered whether the claim as a whole avoids the exclusion to computer software as such, whereas at the USPTO it is assessed whether the claimed invention is patent ineligible. However, the second tests under both systems have more in common, since both look for matter that is more than routine. The test for eligibility under US practice is separate from consideration of novelty and inventive step, although some cases do recognise some overlap between these requirements, whereas under EPO practice an inventive step over the prior art is provided only by the matter having technical character.

EPO tests

At the EPO, every patent application is also examined with respect to novelty and inventive step, among other requirements. The EPO's inventive step requirement corresponds to the USPTO's requirement for non-obviousness. However, the inventive step requirement differs in some aspects from the non-obviousness requirement.

The first hurdle to overcome before the EPO is also a form of eligibility test, but one with a relatively low bar, only excluding subject matter that is entirely devoid of any technical character. A claim that includes any technical means is said to clear the first hurdle to be considered as an invention. This test is often referred to as the 'any hardware' or 'any technical means' approach. This determination is made without reference to the prior art. Therefore, a first step to considering whether a claim is likely to be patentable before the EPO is to assess whether the claim recites a technical entity, particularly hardware. In practice it can be surprising how many claims, particularly method claims, can be found at the initial prosecution stage, which on close inspection do not actually refer to any hardware whatsoever. One relatively easy way of ensuring that the first hurdle is cleared can be to recite "a computer implemented method". In other words, if any hardware (eg, a computer, storage or microprocessor, among other things) is mentioned in the claim, it will pass the first hurdle.

At the second hurdle, the requirement for an inventive step over the prior art is examined. The examination for inventive step is simultaneously subject to a limitation that only aspects of the claimed invention that are technical can be considered. In other words, any matter in the claim that is not considered technical cannot give rise to an inventive step over the prior art. Therefore, at the EPO, the test whether the claimed subject matter fulfils the requirement of 'technicality' is assessed simultaneously with the evaluation of whether the subject matter of the patent application has an inventive step.

Problem-solution approach

The EPO has developed a special process for assessing inventive step, known as the 'problem-solution approach. The problem-solution approach was modified by the EPO for assessing 'computer implemented inventions' (CIIs), which is the term used by the EPO for inventions that are usually realised by means of software and are colloquially called 'software patents'.

Under the modified problem-solution approach, features of the claim under examination are assessed as to whether they contribute to the solution of a technical problem. Only features of the claimed invention are considered that provide such a technical contribution. In some 'mixed type' inventions, being a mix of technical and non-technical claim elements, features can be considered that are non-technical, such as pure software steps, but only if they are said provide a contribution to the formulation of the technical problem solved by the invention.

CII case law

During its existence, the EPO has twice reviewed its case law relating to CIIs in the form of decisions of its Enlarged Board of Appeal. The first decision (G 03/08) from 2010 contains an overview of previous case law on CIIs, which confirmed the two-hurdle test and made no changes to the EPO's approach going forward.

The second decision of the Enlarged Board (G 01/19) was issued in 2021 and concerns the patenting of computer-aided simulations. On the one hand, the principles of the first decision were confirmed and, on the other hand, specific comments were made on the legal problems that arise when patenting computer-aided simulations.

Computer-implemented simulations use a numerical model that is fed with input data and in turn produces data as an output indicative of the result of the simulation. Therefore, only data is processed without directly influencing the physical world. In this sense, a computer-implemented simulation could be considered a purely mathematical process. Mathematical methods as such are excluded from patentability and it could be concluded that computer-implemented simulations are, in principle, not patentable.

In this decision, however, the Enlarged Board of Appeal came to a different conclusion and stated that computer-implemented simulations are not fundamentally excluded from patentability. Instead computer-implemented simulations can be patented if they relate to a technical invention according to the above principles.


The term 'technology' is not clearly defined either in the EPC or case law. Rather, its definition is left open so as not to exclude future technical developments from being patented. However, one is to be guided by what is not technical, which is excluded from patenting under the EPC (eg, mathematical methods, methods for doing business and computer programs), which can be illustrated with an example.

A mathematical solution of a differential equation is a mathematical method and, as such, cannot be patented. However, if the shape of a new antenna is described by this solution of the differential equation and the properties of the antenna are thereby improved, then the resulting antenna is patentable, since it is undoubtedly a technical object. The essential step that led to the invention was the solution of the differential equation. However, it should also be recognised that this mathematical solution has a technical effect when applied to antennas. There are many solutions of differential equations that are unsuitable for antennas, but a technical contribution is provided by the solution of this differential equation as applied to an antenna. In the sense of European patent law, this is also a technical contribution that can be rewarded with patent protection if it is new and inventive.

This is a relatively simple example, which clearly shows the difference between a pure mathematical method and technical subject matter relating to a mathematical method. However, there are also cases where it is much more difficult to draw the line as to whether the matter is technical in the sense of European patent practice.

In the board's decision on computer-based simulations, an earlier board decision relating to '1/f noise' was discussed in detail. The granted European patent arising from this decision relating to 1/f noise defines the simulation of 1/f noise for optimising electrical circuits. Here too, a mathematical procedure simulating 1/f noise is used to optimise a technical object in the form of the electrical circuit. Even if not every simulation automatically leads to a new design of an electrical circuit, the technical contribution was judged to be sufficient for the patent to be granted.

In its more recent decision, the Enlarged Board of Appeal clarified the protection of computer-assisted simulations to the effect that, on the one hand, the technical effect must be present over the entire scope of protection for the claimed invention and, on the other hand, the technical use of the simulation must be defined in the patent claim, although it may also be only implicitly present in the claim.

What does this mean for the 1/f noise example? Looking at the parallel US patent (US 6,795,840 B1), the patent was granted with a claim that was highly similar to the claim of the corresponding European patent. However, the limitation to electrical circuits is missing from the US claim. Here, a "computer programmed to process a method of determining sequences of random numbers of a 1/f noise" was patented. The description of the US patent also states that the simulation of the 1/f noise can also be used to predict "events on the financial markets".

According to the EPO case law, the US claim would likely be considered a purely mathematical method and a business method as such, both of which are excluded from being patented in Europe.

The claim of the US patent therefore contains no indication of a technical use as required by the EPO's Enlarged Board of Appeal. Moreover, the scope of protection of the US patent claim can be said to extend to applications in the financial sector, which are not technical in nature under European practice. The US patent claim is therefore not technical over its entire scope of protection. The US patent would, therefore, be unlikely to be granted by the EPO. The definition of the technical use, namely the use for electronic circuits, is missing from the US claim.

Although this example contrasts one claim that is likely to be unallowable before the EPO as not being technical over its entire scope of protection, following the Enlarged Board of Appeal's decision it is expected that more objections will be raised by the EPO against claims that are not technical over part of their scope. As a result, applicants will need to reduce the scope of their claimed protection during prosecution such that only technical embodiments are covered by the claim.

United States and the EPO – granting CII patents

Further, from the above comparative example, the difference between the granting of patents in the United States and at the EPO relating to CIIs in particular is clear. The EPO has clear rules as to how the technical content of an invention is to be examined. This excludes the granting of patents for subject matter that relates to, for example, purely mathematical methods or business processes as such. In the United States, patents can, in some cases, protect subject matter that is not technical in the sense of European patent practice. Therefore, patents can sometimes be obtained in the United States that are not grantable before the EPO.

Recent US case law, however, increasingly calls on the software in question to improve "computer functionality" (ie, it improves computing speeds or reduces the amount of computing resources required) or perform the computing tasks in an unconventional way. This points in a similar direction to the requirement that an invention must be technical.


Historically, at least, the patenting practice of software patents in the United States is perhaps more generous than at the EPO, but it is not so clear when the software is patent eligible. The distinction between technical and non-technical inventions at the EPO seems to be better defined and therefore clearer, which provides applicants with more certainty prior to application.

Originally published by IAM's Global Patent Prosecution 2022.

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