| 摘要 |
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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