IP-Fälle und Artikel

Strategies for challenging and proving prior art

When it comes to oppositions at the European Patent Office (EPO) every technical field has its own peculiarities. In the field of telecommunications, mobile technology and broadcast technology, standardisation plays a vital role. For this reason, standards related patents are extremely valuable.

As we have seen in some of the recent court battles (Samsung v Apple and Motorola v Apple for example) the weapon of choice for established telecommunications companies is standards related patents. This article introduces the first in a series of guides to tactical opposition, both as opponent and defendant, for businesses and innovators in the electronics and computing sector.

Standards bodies

It is not uncommon for engineers to exchange documents in order to establish a particular technology. Nowadays, standards bodies allow their members to upload documents to a shared server so that those members can easily access and review them in order to assist in defining a standard. Quite often a standards body will have an IPR policy to say that any contribution made by a member represents publication of that technical contribution and so others are free to use that technical contribution. Of course that means that any party making a contribution to the standard will file a patent application relating to that technical contribution before disclosing to the standards body. However, what is the status of documents which are exchanged between engineers (or known to engineers) before the standards body is established?

Prior art

Typically because of the time constraints for filing an opposition it is usual to assume that any document that has been acquired is in the public domain. However, just because a document is dated, does not necessarily mean that that document was in the public domain on that date. For example, typically before work on a standard begins, the standards body sends out a call for technologies. Often documents are submitted in response to that call for technologies and may be presented to other parties. At this point these documents are not necessarily published on a server or submitted to the standards body but are exchanged between the parties intending to contribute to the formation of the standard.

These documents can represent very useful prior art for an opponent wishing to attack a patent. If opposing a patent with documents acquired from engineers, a classic defence is for the patent proprietor to assert that these were not published (or in the public domain) or at least not published on the date that appears on the document itself.

Defence: witness statements

The opposition procedure is relatively stream line. This means that analysis of evidence and documents is as rigorous as time allows by this relatively streamlined procedure. Typically there is also no cross examination of witnesses because the opposition is usually based on written evidence. One thing an opponent can do if a publication date is challenged is to prepare witness statements establishing the what, when, where, how and to whom a disclosure was made. For example, an engineer’s witness statement would detail how long they worked for an organisation, in what role, and note that they were a member of a group which reviewed documents before the establishment of a standards body. This statement should be signed and dated and possibly countersigned. Clearly, the greater the number of witness statements supporting disclosure of a document the better. Furthermore, a witness statement prepared and signed by a person working for a party other than the opponent, though often difficult and time consuming, will add credibility to the witness statement.

Opposition: challenging witness statements

So what does the opponent do in response? Even with the witness statements prepared and filed, that is not necessarily the end of the story. A patent proprietor can still challenge or refuse to acknowledge the witness statements, leaving the opposition division to decide on whether they accept that this document was published on the alleged date or not. The patent proprietor can also use any inconsistency to their advantage. For example, a witness statement purporting to support the disclosure of document A on a certain date which does not mention another document B can be used by the patent proprietor to imply that document B was not published.


The opposition procedure at the European Patent Office represents a very effective way of attacking the intellectual property position of a party. It is relatively inexpensive and can provide rapid results. In some business situations, for example for standards related patents, the validity of the patent is the only factor in question. If the patent is related to a standard then the issue of infringement is rarely reviewed. This means that the opposition may be the only time the patent is challenged.

The supporting evidence and arguments which surround the publication dates of documents can be crucial in successfully opposing or defending an opposition against a European patent. The opposition division should accept the evidence on the balance of probabilities but in reality will be reluctant to revoke a European patent unless certain that a relevant document was indeed in the public domain on the date asserted by an opponent.