| 摘要 |
A scanning apparatus typically comprises 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 that is to be scanned. The essential disadvantage of this apparatus exists in that the length of the path that is traversed by the light beam from the radiation source to the lens arrangement is dependent on the angular position of the prism, so that the light beam is defocussed by the rotation of the prism. The new apparatus shall avoid a defocussing of the light beam. This is achieved through the use of a radiation source, of which the light beam is collimated in such a manner so that it penetrates through the lens arrangement in a lens section that is dependent on the angular position of the prism, and through the use of a lens arrangement that comprises different focal lengths for various lens sections. The focal lengths of the lens sections are thereby selected in such a manner so that the radiation source respectively lies in the focal point of the lens section that is penetrated by the light beam. Optical spacing distance radar for motor vehicles.
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