Method for activating a photocatalytically active outer layer deposited on a composite

The invention relates to a method for activating a photocatalytically active, for example titanium-dioxide-containing, outer layer (13; 23) deposited on a composite, by means of at least one element (14; 24) generating a radiation, for example for generating ultraviolet radiation. The following method steps are comprised here: *a) forming the at least one radiation-generating first element (14; 24) within the composite; *b) forming at least one sensor (16; 26) within the composite; *c) recording an actual value of a physical variable characterizing luminous radiation by means of the at least one sensor (16; 26), wherein the luminous radiation is emitted by a light-generating second element (15; 25); *d) comparing the recorded actual value with a first threshold value within an evaluation device and switching on the at least one radiation-generating first element (14; 24) if the actual value is below or above the first threshold value.