Abstract: The invention enables the realization of an optical and electronic structure of a touch-sensitive area on any flat display surface such as a monitor. The optical structure does not require any additional optical components such as lenses. Laser diodes are likewise not required for the operation of a structure of this type. Large distances and, nevertheless, high sensitivity and high resolution of the touch-sensitive area are accomplished by a novel time-control and location-control of both the emitter diodes as well as the receiver diodes or receiver photo-transistors. If still or moving images are displayed on the surface, the invention can be used as a touch screen and can interactively control the display. A central module simulates a computer mouse and a keyboard.