Initialization control for light beam position indicator

A crossed light beam position indicator includes orthogonal arrays of paired light emitters and detectors for covering a display surface with crossed light beams and scanning means coupled to the emitters and detectors for electronically scanning the orthogonal arrays such that a single emitter at any one time is emitting light. Improved initialization means detect the first occurrence of an interrupted light beam and in response to the first detection, reset the scanning means to the initial reset position to thus avoid transmitting an address that might represent only the edge of an object placed in proximity to the display screen and caught by the scan only after the scan had passed the position occupied by the main body of the object.