Depending on the selected embodiment, the two light-emitting diodes can be constructed differently and in particular can comprise different materials, in particular different semiconductor materials. The two light-emitting diodes 2, 10 can thus also have a different aging behavior. In this embodiment, for example, a corresponding formula and/or table and/or characteristic curve and/or a theoretical model is thus stored in the memory 9 for each light-emitting diode 2, 10, using which the aging behavior of the light-emitting diode is taken into consideration for the ascertainment of the current for generating a desired luminous flux.

FIG. 3 shows a schematic illustration of a program sequence, using which an activation of the light-emitting diodes is carried out, wherein aging of the light-emitting diode is compensated for. At program point 100, current values for the light-emitting diodes, using which desired luminous fluxes are generated, are stored in the memory 9 of the control unit 1. Moreover, a formula, characteristic curve, table, and/or a theoretical model are stored in the memory 9, using which an aging behavior of the light-emitting diodes is taken into consideration during the ascertainment of the current.

At program point 110, the control unit 1 supplies the light-emitting diodes 2, 10 with the original current values for the emission of a desired luminous flux. Simultaneously with the energizing at program point 110, the timer 8 is started.