POSITION DETECTION OF AN ELECTROMAGNETIC BEAM PROJECTION

摘要

The invention relates to the detection of the position of a projection of an electromagnetic beam on a surface such as a laser pointer projection on a display screen. It is suggested to measure intensities of the electromagnetic radiation from the beam projection at three or more different positions at the borders of the surface and to process the measured intensities for determining the centre position of the electromagnetic beam projection on the surface. The intensities may be measured applying only a few low cost receivers. Thus, no optical add-ons or expensive position detection means with a plurality of photodiodes are required