Abstract: An irradiation device which is suitable, in particular, in the field of medicine for photodynamic diagnosis or therapy, comprises a plurality of flat luminous segments (1-4) which respectively generate radiation directed towards a particular irradiation surface (A). The individual luminous segments (1-4) are arranged at an angle to one another so that, when the irradiation device is arranged at a particular distance (D) from the irradiation surface (A), the directed radiations of the luminous segments (1-4) overlap essentially fully on this irradiation surface (A). In this way, homogeneous irradiation of the irradiation surface (A) with a high irradiation intensity will be achieved even in the event that each individual luminous segment (1-4) only has a relatively low irradiation intensity.