Anon, you seem to be making your understanding of the EP system(s) harder than it needs to be, possibly because you are trying to map the concepts onto your model of the US system. I would regard this as a category error!

Just to be clear at the outset, and at the risk of repeating myself, the short answer to your question is that the CJEU does not fit into this system anywhere. There is no avenue of appeal that leads to the CJEU, either via the EPO processes, or the national patent offices. The CJEU plays no role in establishing substantive patent law in any EPC member state.

To take yet another step back, a basic premise of EPC membership is that each member state has harmonised its own national patent laws to the provisions of the EPC. The idea here is that any patent that is valid under the EPC should also be valid in every member state. This is, however, not 100% correct, because each country nonetheless retains sovereignty with regard to the interpretation of the national laws that are nominally harmonious with the EPC. If you are really interested in this, you could research the different outcomes of the ‘Epilady’ case (Improver v Remington) in the UK, Germany and the Netherlands, or the difference in the approach to computer-implemented inventions at the EPO and in the UK courts.

Of course, if the CJEU had anything to do with the EPO or the EPC – which it does not – it could resolve these types of ‘edge cases’ with a ruling that would be binding on all the EPC member states. But it has no such role or power. So when the laws of different countries produce different outcomes, that is just something we all have to live with, just as we would if the EPO did not exist and the patents had all been examined and granted by the individual national patent offices.

As for opposition proceedings, I suspect that this may be one of the most difficult aspects of the system for the American mind to grasp. You see, while administrative proceedings, i.e. IPRs and the like, to challenge patents at the PTAB are relatively new developments in the US, and regarded by some as constitutionally suspect, for many of us in the rest of the world they are a long-standing feature of a well-designed patent system! Many jurisdictions provide for pre- or post-grant opposition of other challenges before an administrative tribunal, rather than a court. Such processes are intended to provide a lower (than judicial proceedings) cost mechanism for third parties to challenge patents that may be improperly granted, recognising that examiners may not have access to all of the prior art and specific technical expertise that may be relevant. Outside the US, there is (and never has been) any presumption of validity. We accept that examiners get it wrong sometimes, and believe that a balanced system should include mechanisms to correct such errors. (You may well disagree with this, which is fine, I’m just telling you how it is out here!)

The UK had a pre-grant opposition system under its 1949 Patents Act (which was replaced by the ‘EPC-ized’ 1977 Act), and retains an administrative procedure for post-grant revocation under section 72 of the 1977 Act.

Generally speaking, a party that disagrees with a national administrative decision has an avenue of appeal to the country’s courts – all the way up to the court of ultimate appeal – just as with PTAB decisions in the US. For EPC member states, such matters are determined entirely in accordance with the national laws and judicial procedures. The CJEU has no role here, either.

By comparison (or contrast, depending on your point of view) decisions of the Opposition Division of the EPO are subject to appeal firstly to the Technical Boards of Appeal, and ultimately (in limited circumstances) to the Enlarged Board of Appeal. The Boards are regarded as administrative courts, and the proceedings as judicial (or, at least, quasi-judicial) in nature. Once these avenues of appeal are exhausted, there is no higher authority – not the CJEU, nor any other body.

So, in summary, and to reiterate one last time, the CJEU has nothing to do with it!