Automotive Distance Control Systems Gmbh

Holger Schanz

Wilfried Mehr

Robert Kraus

A light beam is deflected by refraction and total internal reflection through a first prism, and projected through a first lens onto a scene that is to be scanned. The prism rotates, which varies the deflection angle and scans the beam across the scene along a scan line. Preferably, the successive side surfaces of the prism have different tilt angles relative to the rotation axis, so as to respectively deflect the beam in different deflection planes which cause successive scan lines of the beam across the scene. The emitted beam gives rise to a reflected beam from the scene, which is received through a second lens and deflected onto a photodetector through a second prism congruent to and rotating synchronously with the first prism. This apparatus is suitable as a laser scanning device for an object recognition system or a spacing distance regulation system of a motor vehicle.

Method and apparatus for optically scanning a scene

A scanning apparatus includes a radiation source for emitting a light beam, a rotatable prism for deflecting the light beam, and a lens arrangement for projecting the light beam onto a scene to be scanned. The path length that is traversed by the light beam from the radiation source to the lens arrangement is dependent on the angular position of the prism. To avoid a defocussing, the light beam is collimated so that it penetrates through the lens arrangement in a lens section that is dependent on the angular position of the prism, and the lens arrangement has different focal lengths for various lens sections. The focal lengths of the lens sections are thereby selected so that the radiation source respectively lies in the focal point of the lens section that is penetrated by the light beam. A preferred application is for optical spacing distance radar for motor vehicles.

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Lindau, Germany

Holger Schanz