Patent ID: 8085389

Claim:
An optical sensor based on a transit time principle, comprising: a light source for emitting emergent light pulses into an observed region; a rotating device for rotating a beam direction of the emergent light pulses about a rotation axis orientated vertically to the beam direction; a detector for detecting light pulses reflected by objects in the observed region; a housing for separating an interior of the sensor from the environment and including a partitioning screen that is transparent to the emergent light pulses and to the reflected light pulses; a test device for testing a translucence of the partitioning screen; and a control and evaluation unit, cooperating with the test device, for controlling the light source, for evaluating the light pulses detected by the detector, and for determining a distance of an object using a measured transit time of the light pulses; wherein at least one test detector, mounted on a rotor adapted to rotate about the rotation axis, is provided in the interior of the sensor to form part of the test device; the test detector is oriented toward throughput regions of the partitioning screen through which at least one of the emergent light pulses and the reflected light pulses pass; a test light source, mounted on the rotor and forming part of the test device, supplies the emergent light pulses; at least one reflector element to which the test light is directed is arranged outside the housing; and the test detector is positioned such that it can detect the test light reflected by the reflector element.