The invention relates to a display device having a holding device (2) which can be worn on the head of a user, a multifunctional glass (4) which is fastened to the holding device (2), through said glass the user can perceive the real environment when the holding device is worn, said glass comprising a first and second coupling-out section (9, 7) and a coupling-in section (7), an image generation module (5) which produces an image and couples said image into the multifunctional glass (4) through the coupling-in section (7) in such a way that said image is led in the multifunctional glass (4) to the first coupling-out section (9) which when the holding device (2) is worn effects a redirecting of the image in the direction of the user in such a way that the user can perceive the image in superimposition with the real environment, and a control unit (12); for the image generation module (5). The display device comprises a detector (11) which is connected to the control unit (12) and which measures the intensity of ambient light coupled through the first coupling-out section (9) into the multifunctional glass (4), guided in said multifunctional glass (4) to the second coupling-out section (7), and coupled out of the multifunctional glass (4) through the second coupling-out section (7), wherein the control unit (12) controls the brightness during generation of the image by way of the image generation module (5), the brightness being controlled according to the intensity measured by the detector (11).