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The ‘Background of the invention’ in novelty and inventive step assessment

A patent application typically starts with a section called ‘background of the invention’. According to European patent law the application should indicate the background art which, as far as is known to the applicant, can be regarded as useful to understand the invention (Rule 42 EPC). The rule helpfully adds that, preferably, the documents reflecting such art should be cited.

A good background sets the context and makes it easy to understand the invention. For applicants that is generally a good thing. An Examiner who is convinced that you have an invention may be more sympathetic to your struggle to get the claims to accurately represent that invention. The background helps to ‘sell’ the invention.

On the other hand, ‘anything you say can and will be used against you’. If the background section is to represent state of the art, then your claims should be inventive when compared to it. If your claims are only a non-inventive variation of the prior art in your background, your invention is not looking good. After all, if even the applicant, who it may be assumed has the best interests of the invention in mind, states that something is known, then the public should be able to rely on that.

So can an Examiner cite your background section against you, or not? Reasoning from the EPC, one would think that he cannot. Art. 54(2) EPC defines the state of the art as everything made available to the public (...) before the date of filing of the European patent application. The patent application, of which the background is part, is not available until 18 months after the filing date, not before it.
This question recently played a role before the Court of appeal in The Hague, in a case between Sanofi and Ratiopharm. (Thanks to IEPT for the text of the decision). In section 11.3 the court considers this question as follows (my translation from Dutch):
In so far that the first-instance court must be considered to have only used the background section of the patent to draw conclusions about the teachings of the state of the art, that is not correct, because the background as such is not part of the prior art. In her statement of appeal, in section 5.20, Sanofi correctly points to case law of the EPO, which considers that using the background section in such as manner is deemed unacceptable. The case-law of the EPO acknowledges that the picture that the background section of a patent draws of the prior art may be based on personal prejudices or views of the inventor / patent attorney and so should be used reluctantly.
At least the Dutch court of appeal is of the opinion that your background section cannot be cited against you as part of the prior art. Unfortunately, the decision does not say which EPO case-law swayed the court.

One decision which, to some extent, supports the court’s point of view is T 654/92. A document was acknowledged in the patent. In the course of the oral proceedings it became clear though that it did not form part of the state of the art, but represented internal knowledge of the applicant's company. Any such art was to be ignored in an assessment of inventive step.

However, there is case law which has a stricter point of view. For example, in T 1073/02, the application contained a drawing "Fig. 6" with the title "background art", together with an explanation of the drawing. According to the applicant that figure did not relate to known prior art. However no explanation could be given why the figure was titled so. The board wanted to consider it as part of the prior art, and even as the closest prior art. The board required “sound evidence in support of the contention submitted by the appellants that said "background art" is not contained in the prior art”. The board then observes that no such evidence has yet been provided. After the case is remitted, the applicant succeeds in explaining the origin of the background art to the Examining division and obtains a grant after all.

Although the standard of proof appears to differ in these decisions, both of them seem to assume that an admission made in the background art is part of the state of the art until reasons are given why the admission was made erroneously.

For these reasons I would not agree to a blanket statement saying that before the EPO ‘background as such is not part of the prior art’. Likely the discussion before the court was more nuanced than can be gleaned from the decision alone. One should prudently assume that admissions made in the background may be cited against you. Good advice is given by Rule 42 itself: if you are going to describe prior art, then preferably, cite a document reflecting such art. It will stop you from disclosing anything that is not public.