At the PatInfo2015  conference in Ilmenau I gave an update on my article published in World Patent Information on Successful EP-oppositions (World Patent Information Volume 35, Issue 2, June 2013, Pages 126–129 )


General information

The continuation of the study to the opposition behaviour of the EPO is showing a stable opposition rate over the last years and is almost 5% over the last five years (2010-2014) and, in other words, effects about 1 out of 20 granted patents.


When an opposition is filed, it tells you of course something about the importance of the granted patent. And also the opposite can be true, as there has not been filed an opposition it is probably not of interest to anyone.


When a patent survives an opposition, it says of course something about it’s strength. Over the last years (2010-2013) the deviation over the three possible outcomes is equal (three third each : revoked/ amended/ unchanged). Statistics on this is very risky as we know that a lot of opposition cases are settled before a decision is taken (and mentioned in the database as “opposition withdrawn”)



The opposition strategy for companies is also very different. Some companies are very active in filing oppositions, while others do not see any reason to do so. Very often, in small markets with only a few players, you see an active opposition policy. Each player tried to defend his/her own territory and to create a freedom to play. You can have some doubts whether or not this is wise, or is waste of money. Maybe more strength can be created in joining force and making good settlements, respecting each other’s Patent-portfolio.



Before search for documents useful in opposition,  it is good to have a clear view on the way the EPO is looking to Inventive Step (article 56).

It is a three step process based on the Problem-Solution Approach (PSA).

The three steps are:

  1. Define the closest prior art (document 1 )
  2. Define the technical problem
  3. Examine whether or not the solution is obvious based on published prior art (document 2)

Most the time document 1 is already found during the examination at the EPO, but document 2 is more trickier.

Some case law can be of help:

  • Old documents are hardly accepted (< 50 years old)see for example (T 261/87“70 year”T 366/89 “90 year”and T 404/90 “65 year”)
  • Documents can also come from a different technical area (other IPC-class) See for example T 0302/02

How this procedure in practice is works is in detail pointed out in the case T1254/08 where the opposition procedure is described between Unilever (opponent) and Gillette (Applicant) about EP1183005 .


Document D12 is the closest prior art (step a!), and in point 4 (page 8) the technical problem (step b!) is defined,  while Documents D10 (and also D9) (step c!) teaches a person skilled in the art to come to the proposed solution without any inventive ingenuity and thus the patent is lacking an inventive step in view of article 56.


The main issue for searching is finding documents useful in the third step (document 2).


This needs excellent search skills as well as reading documents in full-text, as the arguments maybe hidden somewhere in the description.


I hope this guidelines will help you for future opposition searches!


If not, ask Patent Information Services to perform the search for you.

Aalt van de Kuilen

Senior Patent Information Specialist in the field of Life Sciences and Chemistry. Read more about the background and expertise of Aalt van de Kuilen.