Legal framework
A European patent may be opposed within nine months of publication of the mention of grant: Article 99(1) EPC. Since the mention of grant of EP-G was published 8 months ago, Mr O is still within the opposition period, assuming the notice of opposition and opposition fee are filed in time.
The grounds for opposition are exhaustively listed in Article 100 EPC. They include lack of patentability under Articles 52 to 57 EPC, insufficiency under Article 100(b) EPC, and added subject-matter under Article 100(c) EPC. Lack of clarity under Article 84 EPC is not listed. The case law confirms that lack of clarity is not itself a ground for opposition; see for example T 23/86, T 565/89, and the Case Law summary at IV.C.5.1.2(c).
For novelty, Article 54(2) EPC provides that the state of the art comprises everything made available to the public before the filing date, whether by written description, oral description, use, or any other way. A product put on the market before the filing date can therefore be prior art. The Guidelines confirm this for marketed products in G-IV, 2 and for prior use allegations in G-IV, 7.2.
Statement a)
True.
Lack of clarity is not a valid ground for opposition.
Even if claim 1 has two possible interpretations, an opposition cannot be based merely on the allegation that the claim is unclear. Article 100 EPC does not include lack of clarity as an opposition ground. The established case law confirms that an opposition cannot be filed on the basis that granted claims lack clarity, see T 23/86, T 565/89, T 89/89, and Case Law IV.C.5.1.2(c).
Statement b)
False.
If product Z was put on the market by Mr G before the filing date of EP-G, it can still form part of the state of the art.
EP-G was filed without priority in January 2020. Product Z has been on the market since November 2019, i.e. before the filing date of EP-G. Under Article 54(2) EPC, the decisive issue is whether the product was made available to the public before the filing date, not who made it available.
A product put on the market before the filing date is normally prior art. The Guidelines state in G-IV, 2 that such a marketed product is part of the state of the art, and that all analysable properties of that product are also part of the state of the art; this follows from G 1/23.
Statement c)
True.
A valid element of advice is to oppose EP-G for lack of novelty, relying on product Z as prior art.
Lack of novelty is a patentability objection under Article 54 EPC, and therefore a valid ground for opposition under Article 100(a) EPC. Since product Z was on the market before the filing date of EP-G, it may be relied on as prior use or prior availability under Article 54(2) EPC.
Because claim 1 has two possible interpretations, Mr O should explain in the notice of opposition why one technically reasonable interpretation of claim 1 covers product Z and why product Z therefore anticipates the claimed subject-matter. The notice of opposition must contain the grounds, facts and evidence relied on: Rule 76(2)(c) EPC and Guidelines D-III, 6. For prior use, the EPO will normally need to know when the use occurred, what was used, and the circumstances showing public availability: Guidelines G-IV, 7.2.
Statement d)
False.
Product Z does not need to be disclosed in a written publication in order to be prior art.
Article 54(2) EPC expressly covers anything made available to the public by written description, oral description, use, or any other way. Public sale or public use of a product before the filing date can therefore be novelty-destroying prior art.
Exam tip
In opposition questions, do not attack granted claims directly for lack of clarity. Instead, ask whether the ambiguity can be used to support a valid opposition ground. Here, the useful ground is lack of novelty under Article 100(a) EPC and Article 54 EPC, based on the prior marketed product. For prior use, always state and prove the three points from Guidelines G-IV, 7.2: when, what, and under what public circumstances the product was made available.
Legal Disclaimer
The information provided in this post is for general informational purposes only and does not constitute legal advice. This content should not be used as a substitute for professional legal advice tailored to your specific circumstances. For advice related to any specific legal matters, you should consult a qualified attorney.