Arbitrary size reduction and antenna placement: non-technical

The application underlying the discussed decision concerns a hearing aid comprising a rigid printed circuit board (PCB) with an indentation at its edge to accommodate at least part of an antenna terminal from a separate flexible printed circuit board. The features at the center of the decision were the “indentation” features (h) to (j), which the Board found did not credibly achieve any technical effect, such as size reduction or correct antenna placement, over the entire breadth of the claim. Because no credible technical effect could be established, the Board treated these distinguishing features as arbitrary modifications of the prior art that could not contribute to inventive step.

Here are the practical takeaways from the decision: T 0094/24 (Indentation in a hearing aid/GN HEARING) of 19 January 2026, of the Technical Board of Appeal 3.5.05.

Key takeaways

The invention

The Board of Appeal summarized the invention as follows:

The opposed patent relates to a hearing aid comprising an antenna arranged on a flexible printed circuit board (FPCB). A perennial challenge in hearing aid design is minimizing physical size while ensuring robust mechanical and electrical connections. The patent proposes a specific assembly geometry between the hearing aid’s rigid PCB, which carries signal-processing electronics, and the antenna-carrying FPCB. The rigid PCB is provided with an “indentation” (a recess or cut-out) at its edge. The antenna terminal on the FPCB is connected to a pad on the rigid PCB at an angle between 30 and 150 degrees, and at least part of the terminal is accommodated within the indentation. According to the patent, this arrangement facilitates compact connections compared to traditional surface-mount or wire-bridged solutions.

Is it patentable?

The Opposition Division’s position

The Opposition Division rejected the opposition and maintained the patent as granted. It considered document D2 (US 2015/0036854 A1) as a suitable starting point and noted agreement between the parties that features (h) to (j), relating to the indentation accommodating at least part of the antenna terminal, were the sole distinguishing features over D2. The Opposition Division found that these features provided a sufficient technical contribution to establish an inventive step.

The Appellant’s arguments

The opponent (appellant) argued that features (h) to (j) did not provide an inventive step over D2. Its core argument was that if there is no credible technical effect, there is no technical contribution, and therefore no inventive step. The opponent demonstrated with specific examples and drawings that the broad claim wording, particularly “accommodating at least a part”, allowed for embodiments where none of the alleged effects (size reduction, correct placement, alignment) would be achieved. For instance, a wide notch accommodating a narrow terminal results in a “floating” configuration with no mechanical support.

The Board’s analysis

Credibility of alleged technical effects

The Board assessed whether the alleged effects of features (h) to (j) were credibly achieved over the whole scope of claim 1. The proprietor alleged three effects: size reduction, correct placement, and correct alignment. The Board found none credible:

1. No credible “correct placement”: The expression “at least a part” allows “laterally unconstrained” embodiments where the indentation is significantly larger than the terminal, providing no mechanical guidance.
2. No credible “alignment”: Claim 1 does not require the terminal to be parallel to the PCB surface. A terminal at a significant skew angle still falls within the claimed scope.
3. No credible “size reduction”: The claim encompasses embodiments where the indentation is in a raised portion of the PCB (potentially increasing Z-height), and large indentations may require enlarging the PCB footprint.

Arbitrary features and inventive step

Since no credible technical effect was established, the Board concluded that features (h) to (j), while undoubtedly technical in nature, did not credibly contribute to solving a technical problem. Citing extensive case law (T 37/82, T 176/97, T 746/22, and many others), the Board held that such features are “arbitrary” or “non-functional” modifications that cannot support an inventive step, even if the skilled person would never think of such a modification.

Auxiliary requests and referral

1. Auxiliary requests 1-3 were not admitted under Article 13(2) RPBA (no exceptional circumstances). The Board also found them not prima facie allowable: request 1 (indentation dimensions) still left the “floating” problem unresolved; request 2 (negative limitation excluding raised portions) raised concerns under Articles 84, 123(2) EPC and G 1/03; request 3 (specifying “solder”) involved an arbitrary choice of a standard material.
2. Referral to the Enlarged Board: The proprietor argued the Board’s approach was a “novel doctrine” unique to Board 3.5.05 and limited to mixed-type (COMVIK/software) inventions under G 1/19. The Board refused the referral, confirming this principle is consistently applied across all technical fields and represents decades of established jurisprudence, not a departure from G 1/19 or G 2/21.

Conclusion

The Board set aside the Opposition Division’s decision and revoked the patent. Features (h) to (j) did not credibly achieve any technical effect over the whole scope of claim 1 and thus constituted arbitrary modifications that could not contribute to inventive step under Article 56 EPC. This decision is notable for its explicit confirmation that the principle of treating features without credible technical effect as arbitrary applies to all inventions, extending the reasoning familiar from COMVIK and G 1/19 well beyond mixed-type computer-implemented inventions.

More information

You can read the full decision here: T 0094/24 (Indentation in a hearing aid/GN HEARING) of 19 January 2026, of the Technical Board of Appeal 3.5.05.

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