T 1208/22 13-03-2025

1. The appeal is admissible.

2. Sufficiency of disclosure (Article 83 EPC)

2.1 Claim 1 is directed to a method of operating an UV lamp. The UV lamp is repeatedly activated and turned off in a series of activation cycles. Such lamps may disinfect an environment, e. g. a lavatory inside a vehicle or an aircraft. This is described in the paragraph bridging pages 8 and 9 or on page 14 lines 3-14 of the originally filed description. The goal of the claimed method is to assure the maintenance of the antimicrobial effect caused by the UV light at a certain target level.

2.2 The claimed method defines various steps, as follows:

(i) provision of a supply power to the UV lamp

(ii) activating the UV lamp during a series of activation cycles

(iii) sensing the UV light and measuring an optical parameter related to its antimicrobial efficacy during at least one activation cycle,

(iv) adjusting the supply power to maintain a target antimicrobial efficacy

2.3 Carrying out the individual method steps defined in the claim as such does not present the skilled person with any difficulties. The objections of the Examining Division relate to the claimed feature that the adjustment of the supply power of the UV light should be carried out in such a way as to "maintain a target antimicrobial efficacy (...) over the series of activation cycles".

2.4 In the Examining Division's view the supply power adjustment being carried out during or after one of the activation cycles was insufficient to "maintain a target antimicrobial efficacy (...) over the series of activation cycles". In view of the multitude of activation cycles, and in view of events possibly taking place between the activation cycles the application lacked sufficient disclosure on how such an adjustment may maintain a target dose over the whole series of activation cycles, see point 2.2.16 of the decision. Debris could e. g. accumulate between the first and the second activation cycle which could not be accounted for if no regular sensing was carried out. The claim required sensing only once, it did not require a control loop where sensing and adjusting would be carried out in each activation cycle. The Examining Division concluded thus that the claim covered situations in which a skilled person would not know how to maintain a target antimicrobial efficacy based on the information obtained from sensing the properties of the UV light, since it was unknown how to adjust the supply power for future cycles.

2.5 In the Board's view, however, such a finding does not lead to the claimed method to be insufficiently disclosed.

2.5.1 The Board agrees with the Examining Division insofar as there are indeed ways of carrying out the claimed method which lead to the antimicrobial efficacy not being maintained. As mentioned in the description (page 6 line 15 to page 7 line 5) there are various reasons for which the lamp's UV intensity may decline, e. g. deposit of light absorbing particles in the interior of the lamp or of debris on the external surface. Thus, if sensing does not take place often enough such a decline may remain unnoticed and the antimicrobial efficacy may become insufficient.

2.5.2 However, the mere fact that the claim covers embodiments which do not lead to the result defined therein, i. e. the maintenance of a target antimicrobial efficacy, is on its own not sufficient to conclude that the claimed method is insufficiently disclosed. It is established jurisprudence of the Boards of Appeal that occasional failures are of no harm to the sufficient disclosure of an invention as long as a skilled person knows how to transform failure into success, see Case Law II.C.6.6, II.C.5.2 or G 01/03, point 2.5 of the reasoning. Thus, what needs to be assessed is whether a skilled person would, in general, be in a position to carry out the claimed method and, in case of failure, would know how the desired result may nevertheless be achieved.

2.5.3 It was undisputed that the description contains instructions on how to perform the claimed method, see e. g. the flowcharts in figures 5 or 13 and the corresponding explanations in the description. When implementing this method a skilled person would have to choose a frequency of sensing/adjustment events to start with. If it turned out that the target antimicrobial activity cannot be maintained in this way, a skilled person would know what to do, i. e. to increase the frequency of the sensing/adjustment cycles. This is also defined in original claims 8 and 9. It is self-evident that this frequency depends on the circumstances of the case and cannot be generally defined in the claim. In some cases it may be sufficient to sense/adjust only rarely, in others a tighter schedule may be necessary. A skilled person is not confronted with any situation requiring more than common sense in order to know what to do.

2.5.4 The Board also considers that, as submitted by the appellant, to "maintain a target antimicrobial efficacy of the UV light (116) over the series of activation cycles", as defined in the claim, must be interpreted in a technical meaningful sense. This feature cannot be interpreted as meaning that the antimicrobial efficacy remains constant on an even level. A technically meaningful cycle of sensing and adjusting for maintaining a certain output requires a defined interval of acceptable output values. An adjustment is then only made if the output is outside such a predefined interval. A certain fluctuation is inherent to any control loop. There is no fundamental insufficiency of disclosure linked to the fact that the antimicrobial efficacy cannot be maintained on exactly the same level throughout the series of activation cycles.

2.6 In summary, the method defined in claim 1 of the appellant's main request is sufficiently disclosed. The appellant's auxiliary requests need not be considered.

3. Remittal (Article 111 EPC)

The Examining Division refused the patent application under Article 97(2) EPC because claim 1 did not comply with the requirements of Article 83 EPC. No other grounds have been given for the refusal of the application.

From the file history it is not clear whether the examination of independent claims 1 (method) and 11 (apparatus) with respect to other patentability requirements, in particular novelty (Article 54 EPC) and inventive step (Article 56 EPC), has been concluded. The Board notes that a variety of such objections had been raised during the examination procedure.

The Board considers this to be a special reason for remittal for further prosecution, as defined in Article 11 RPBA. Thus, the case is to be remitted to the Examining Division for further prosecution.