A touch screen input system (10) for use with a display screen (12) having a photo-active display surface including a controllable sweeping beam. The system includes at least one photo-detector (20) in combination with detection circuitry for continuously registering the position of the beam in the display surface. A pointer (26) is adapted to reflect light from the beam to the photo-detector to provide a latch signal which is used to hold a signal identifying display screen location corresponding to pointer means location.
