The Interpretive Weight of Reference Signs: T 0903/24 on Rule 43(7) EPC
Are reference signs truly legally invisible? In T 0903/24, an EPO Board of Appeal explicitly used reference signs to interpret claim features during a novelty attack, highlighting a subtle limit to Rule 43(7) EPC.
Drafting a claim for a mechanical device like a refrigerator door often involves sprinkling reference signs throughout the features to satisfy the examining division under Rule 43(7) EPC. We are taught that these numbers are legally invisible, present only for convenience, and cannot limit the scope of protection. But what happens when a board of appeal actually uses those very reference signs to interpret the claim's technical meaning during a novelty attack?
The interpretive weight of reference signs
In T 0903/24, Board 3.2.03 confronted exactly this scenario in a case concerning refrigerator technology. The proprietor's main request faced a novelty objection, and the debate hinged on how to construe the claimed features.
The mandate of Rule 43(7) EPC is clear: reference signs shall not be construed as limiting the claim. Practitioners routinely rely on this provision to assure clients that adding numbers from the drawings will not narrow the patent's scope. However, the board took a highly unusual methodological step. As highlighted in the decision's catchword, the panel explicitly affirmed the use of reference signs for claim interpretation (reasons 2.8.2).
This approach reveals a subtle doctrinal distinction. While a reference sign cannot restrict a broad claim term solely to the specific embodiment shown in the figures, it can inform the objective technical understanding of what that term means in the context of the invention. By anchoring abstract wording to concrete structural relationships in the drawings, the reference signs helped the board determine the feature's true technical scope. In this instance, that interpretive clarity worked against the proprietor, resulting in a finding that the main request lacked novelty.
The procedural boundary for late objections
With the main request falling to the novelty attack, the proprietor relied on auxiliary request 2. At this stage, the opponent attempted to introduce new objections. Crucially, these objections were raised only after the notification of the board's communication under Article 15(1) RPBA.
The admission of such late submissions falls entirely within the board's discretion. The panel exercised this discretion and decided not to take the new objections into account, ultimately finding auxiliary request 2 allowable.
This strict enforcement of procedural economy provides a fascinating contrast to other recent decisions. For example, in T 0882/24, a different board overturned a first-instance discretionary decision and admitted a late-filed novelty objection because the opposition division's prima facie technical assessment was flawed (T 0882/24, reasons 2.3.2). In that case, the board was willing to assess the underlying merits de novo.
In T 0903/24, the opponent found no such flexibility. The board held the line at the Article 15(1) RPBA communication. Once that preliminary opinion is issued, the door for new attacks is firmly shut.
Practical implications
This decision provides two critical lessons for European patent attorneys.
First, practitioners must stop treating reference signs as entirely legally inert. While Rule 43(7) EPC prevents them from explicitly limiting the claim, T 0903/24 demonstrates that a board can use them as an interpretive tool to establish the technical meaning of disputed features. When drafting or amending claims, ensure that the reference signs point to embodiments that genuinely support your intended breadth.
Second, the strict disregard of new objections raised after the Article 15(1) RPBA communication reinforces the absolute necessity of front-loading all attacks. Unlike the situation in T 0882/24, where a flawed first-instance decision provided a gateway for late submissions, an opponent facing a ranked set of auxiliary requests must raise all conceivable objections early. Waiting until the board issues its preliminary opinion to attack a lower-ranking request is a procedural gamble that will almost certainly fail.