Optical scanning device for reading bar-code symbols

摘要

The subject-matter of the invention is an optical scanning device for reading bar-code symbols, in the case of which device a transmitted light beam (which is emitted by a light transmitter) is deflected via a multi-facet polygon and is aligned by means of an autofocus device, to form a small light-spot diameter, with a reading plane, and the received light beam (which flows back coaxially with respect to the transmitted light beam in accordance with the autocollimation principle and whose power is modulated by the different reflection of the bars and the background of a code pattern) passes via receiving optics to an evaluation unit, both the transmitted light beam and the received light beam being deflected via the same facet of the polygon. The object of the invention is to improve such a scanning device. This object is achieved according to the invention in that at least the normal to the surface of one facet of the multi-facet polygon (9) encloses an angle xi NOTEQUAL 90 DEG with respect to the rotation axis of the polygon (Fig. 2). <IMAGE>