Overturning Discretionary Decisions: T 0882/24 on Flawed Technical Assessments
When an opposition division refuses to admit a late-filed document based on a flawed technical assessment, the Board of Appeal can overturn that discretion. T 0882/24 illustrates how inherent disclosures unlock de novo review.
Defending a European patent often involves a sigh of relief when the opposition division declines to admit a late-filed novelty attack based on a quick prima facie assessment. When the division concludes that a prior art document simply does not disclose a crucial feature, the procedural door seems firmly shut. But as T 0882/24 demonstrates, that door can swing wide open on appeal if the Board of Appeal finds the division's underlying technical reasoning to be flawed.
The acoustic interplay in the ear canal
The opposed patent relates to an active hearing protection device designed to reduce the occlusion effect, which causes a boomy perception of one's own voice, and the isolation effect caused by uneven passive attenuation. Claim 1 of the main request required a controller that processes signals taking into account "individual acoustic characteristics" of the occluded ear canal. The opposition division maintained the patent on this basis, refusing to admit a late novelty objection based on document D1 because they believed D1's filter did not use these individual characteristics.
Overturning the discretionary decision
The opponent appealed, arguing the division's prima facie assessment of D1 was wrong. The proprietor countered that the opponent should have raised the apparatus claim objection earlier, rather than restricting its initial attack to the method claim.
The panel rejected the proprietor's procedural argument. The board held that if a discretionary decision not to admit a submission is based on a flawed technical or factual assessment by the opposition division, the board may overturn that discretionary decision to assess the underlying merits of the submission de novo (reasons 2.3.2). Because D1's transfer function inherently relied on individual tuning, the division's technical premise was incorrect, justifying admittance under Article 12(6) RPBA.
Inherent disclosure of individual traits
Having admitted the objection, the board turned to Article 54 EPC. The proprietor argued that D1 targeted a general cohort and did not measure individual traits like ear canal shape or eardrum impedance.
The board disagreed. D1 defined a transfer function measured from noise to ear, through the headphones and with feedback active noise reduction being active. The board noted that characterising this transfer function is technically impossible without taking the individual characteristics of the user's ear canal into account (reasons 3.4.3). Furthermore, D1 adjusted filters based on the user's own-voice response. The board explained that this response is shaped by the acoustic environment, meaning the individual's occluded ear-canal acoustics are directly and unambiguously taken into account. Consequently, the claim lacked novelty.
The limits of exceptional circumstances
Faced with the loss of the main request, the proprietor filed auxiliary request 3 after the board's communication under Article 15(1) RPBA. They argued that the board adopting the opponent's broader construction of the acoustic characteristics constituted exceptional circumstances under Article 13(2) RPBA.
The board firmly rejected this. The opponent had advanced this exact interpretation in their statement of grounds of appeal. A board issuing a preliminary opinion that concurs with an appellant's long-standing argument does not constitute an "exceptional circumstance" (reasons 4.2). Furthermore, the amendment introduced new added matter issues under Article 123(2) EPC by conflating the gathering of information with the definitive determination of characteristics.
Practical implications
For practitioners, this decision clarifies the boundaries of discretionary review and late-filed requests:
- A first-instance decision not to admit a late submission is not shielded from appellate review if the technical foundation of that prima facie assessment is demonstrably wrong.
- Opponents should meticulously document why a division's technical reading of a late-filed document is flawed, as this can unlock de novo consideration on appeal.
- Proprietors cannot rely on a favourable preliminary opinion as an excuse for late filings. If an opponent clearly outlines a claim construction in their grounds of appeal, fallback requests must be filed with the reply.