Patent ID: 7307738

Claim:
A beam catcher for a light beam ( 2 ) pulsating in amplitude at a modulation frequency (f) with a photodetector ( 4 ) with a plurality of photo sensors ( 6 ) that are offset in a spatially defined manner relative to a reference point ( 5 ), an evaluating circuit ( 7 ), and an output device ( 8 ), wherein a phase shifter ( 10 ) that is sensitive to the modulation frequency (f) is arranged between at least two of the plurality of photosensors ( 6 ); wherein the phase shifter ( 10 ) includes two end points ( 11 ) connected to the evaluating circuit ( 7 ), which is connected to the output device ( 8 ); wherein the pulsating light beam ( 2 ) received by the photosensors ( 6 ), depending on an offset (V) relative to the reference point ( 5 ), shifts the phase between the two end points ( 11 ); and wherein the evaluating circuit ( 7 ) derives the offset (V) and controls the output device ( 8 ).