Scanner for the optical scanning of objects

摘要

In a scanner for the optical checking of objects such as CD-discs there is provided a coherent light source; a light deflecting device which allows a light beam emitted from the light source to sweep over the object in a substantially linear scanning movement, with the optical axis of the light beam subtending a small angle with a normal to the object surface transverse to the scanning direction; and a detector for detecting light which is reflected back from the object. In the present arrangement the optical axis of the light beam also subtends a small angle with the normal to the object surface in the scanning direction. This makes it possible to avoid disturbing modulation of the detector signal due to interference effects.