EP 3 346 733 B1 relates to a hearing aid having a slot antenna.
The antenna is used for wireless data communication between, for instance, two hearing aids in a binaural hearing-aid system.
Brief outline oft he case
The OD rejected the opposition and the opponent appealed.
The board admitted in appeal the interpretation of the feature “a slot” and concluded that claim 1 as granted infringed Art 123(2). As all AR where either not admitted or not allowable, the patent was revoked.
The proprietor’s point of view
Admissibility of the objection
The proprietor argued that the opponent questioned the function of the “a slot” for the first time in its statement of grounds of appeal. It characterised this as a “radical departure” from the line of argument presented in the first-instance proceedings, where the opponent had consistently argued that “slot antennas” and their slots were notoriously known radiating elements.
On the interpretation of the term slot
The proprietor argued that the skilled reader would immediately understand that the term “slot” refers to the radiating slot of the slot antenna. For the proprietor, a “slot” was by definition a “narrow opening or gap“, whereas an “opening“, such as for a battery, is a “hole that allows access“. The proprietor argued that interpreting the slot as a “giant opening which would fit the battery” would be technically absurd.
The proprietor further argued, with reference to T 1354/18, that claim interpretation should not be based on a purely linguistic analysis but must yield a technically sensible result. The proprietor asserted that the board’s focus on the indefinite article “a” was overly formalistic and failed to apply the concept of a “mind willing to understand“.
The proprietor also submitted that the board “did not read the claims in accordance with the law”, failed to follow the instructions of G 1/24 and the EPO Guidelines, and stated that it was “a shame” that the board “wanted to revoke the patent” based on language details and nitpicking.
The board’s decision
Admissibility of the objection
The opponent’s “new argument” relates solely to the interpretation of the claims.
Determining the correct meaning of the claims is a question of law for the board to decide when assessing their compliance with the requirements of the EPC, irrespective of whether the parties have previously presented any arguments on this matter. The board referred to R 25/22, Reasons 12; R 14/23, Reasons 7, in the context of Art 54(2), and T 737/22, Reasons 3.2.
To exclude a technically viable interpretation of a claim feature simply because it was not explicitly articulated before the OD would prevent the board from assessing the relevant scope defined by that claim.
This means that the opponent’s argument regarding the interpretation of the term “a slot” is indeed suitable to address the issues which led to the decision under appeal.
Accordingly, at least for this reason, the board decided to admit the opponent’s argument concerning the interpretation of “a slot” into the appeal proceedings.
Claim interpretation
The board interpreted the feature “a slot” as referring to a structural element provided in the “electrically conductive material”, which is not necessarily identical to the radiating element, i.e. the radiating slot of the antenna, implied by the term “slot antenna”.
Claim 1 as granted uses the indefinite article “a” to introduce “a slot“, rather than referring back to “the slot” of the “slot antenna“. While a “slot antenna” inherently comprises a radiating slot, the claim wording does not preclude the presence of additional slots in the conductive material.
From a technical perspective, such additional slots are however well technically meaningful. A “slot” in the conductive material of a hearing-aid faceplate could serve various purposes including non-radiating ones, such as ventilation, strain relief or acoustic tuning.
Furthermore, a “slot” could perform electromagnetic functions other than radiation. For instance, it could act as a resonator or filter to absorb specific frequencies, as a reactive loading element to adjust the impedance or as a feeder to couple energy to another layer. Hence, interpreting the term “a slot” as a non-radiating slot is a technically sensible construction that falls within the broad meaning of claim 1 as granted.
The proprietor’s distinction between a “narrow slot” and a “large opening” is contradicted by the opposed patent itself. Paragraph [0050] of the patent specification states that the “slot 35 may form an opening in the conductive material 34″. Furthermore, this paragraph discloses that a “further opening 36” is provided within the loop formed by the “slot” to accommodate the battery.
Thus, the opposed patent explicitly envisages a configuration in which a “slot” forms an “opening“. Since the battery opening (36) is also a “hole” provided in the electrically conductive material (34) on the face plate (32), it satisfies all the structural requirements.
Without the functional limitation that the slot be “configured to cause emission of an electromagnetic field upon excitation”, which was present in “item 1” on pages 22 and 23 of the application as filed but was not present in claim 1 as granted, claim 1 as granted contains no limitation that would allow the skilled reader to distinguish the “radiating slot” from other openings or slots provided in the same “electrically conductive material”.
For the board, the often-cited “mind willing to understand” does not imply an intention to ignore the actual scope of a claim in order to ensure its allowability under the EPC.
The “non-radiating slot” interpretation is indeed a technically sensical construction. Excluding the technically viable embodiments of the “slot” simply because of the proprietor’s subjective intention to limit the claim to a radiating slot would amount to disregarding the skilled reader’s objective understanding of the claim and disregarding its erga omnes effect.
Boards of Appeal do not only act in the parties’ interests but also in the interest of the public and legal certainty. In this context, when assessing whether a claim complies with the requirements of the EPC, including the requirement of Art 123(2), in view of the interpretation of the claim that identifies all technically sensible interpretations of what these claims covers, the board fulfils its judicial duty.
Regarding the conclusions of G 1/24, the board noted that this decision requires the description and drawings to be consulted when interpreting claims. This was done in the present case.
The fact that the board’s objective interpretation of the claims differs from the proprietor’s preferred, subjective interpretation, does not constitute a misapplication of the law.
Comments
The board is to be followed when it considers that the interpretation of a claim is a matter of law and can be raised in appeal. Otherwise a board would be stuck with the interpretation of the claim decided by a first instance division. No judicial revision of the first instance decision would be possible, which is an absurd consequence.
The present case reminds also that, any technically sensible interpretation of the claim has to be taken into account.
If one of those interpretation is in conflict with the requirements of the EPC, it will lead to the corresponding objection.
The “mind willing to understand” is not just what the applicant/proprietor wishes to be understood. It just prevents absurd interpretations to be taken into account.
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