Apart from being novel and susceptible of industrial application, an invention also has to be inventive in order to qualify for a patent. When it comes to novelty the benchmark is fairly objective. If an invention appeared in a comic book either yesterday or at some time in the past, it can no longer be classified as novel. However, even if an invention is novel, this does not automatically mean it is inventive.
Point of departure to assess this is the so-called 'prior art'. This refers to everything that was in the public domain prior to the date on which the patent application was filed, due to it having appeared in a local newspaper or having been presented at an exhibition, for example. In order to be inventive the invention may not be obvious for your average person skilled in the art. It is not about whether the inventor himself was inventive when he developed his invention. This means that a very simple invention can still be inventive.
Solve a problem
In Europe, an invention is assessed by studying the measures which, according to the invention, are taken to solve a particular problem. These measures are often described in various different documents. The person skilled in the art could have combined these measures. The question is whether he would have done so in order to arrive at a solution for his problem.
Suppose, we go back in time and assume you have invented a table with four legs, one of which is adjustable in height. The nearest prior art is a table with four ordinary legs. The problem to be solved: how do you ensure the table is stable on an uneven surface? If there were already such a thing as a stool with three ordinary legs and a telescopic one, then the application for this leg for another piece of furniture such as table would be obvious. In that case your invention would not be inventive.
It becomes less clear when, apart from the ordinary table, the only other thing known to have an adjustable leg is a crane. If this is, for example, described in a brochure about cranes, then this invention is inventive. A furniture maker is not deemed to consult brochures on cranes. But what happens when the crane is described in a newspaper article headed 'How to deal with uneven surfaces?'. A furniture maker who wants to solve a problem might be tempted to read such an article. This means that the inventive step is subjective.
In Europe, the EPO (European Patent Office) determines whether or not an invention is inventive. It is one of the tasks of a patent attorney to convince the patent researchers of the EPO that a person skilled in the art does not have any reason to combine different documents in order to arrive at the invention. When drafting the patent application it is furthermore important to be well aware of the prior art. This is why a patent attorney will conduct a literature search. When drafting the patent application he or she will take the known literature into account so that, in the actual patent application, the invention is described as clearly as possible in relation to the prior art.