Optoelectronic device for recognizing contrast marks

摘要

The invention relates to an opto-electronic device for recognising marks having defined contrast patterns, with a transmitter emitting a light beam and a receiver. The transmitted beam is moved periodically over the marks by means of a deflecting device, whereby the received beam reflected by a mark exhibits amplitude modulation according to the contrast of the marks and dependent upon the spatial intensity cycle of the transmitted beam. The received light is converted in the receiver into an analog received signal. The analog received signal is converted in an n-bit analog-digital converter (15), the word width of which is n greater than one, into a digital received signal which is taken to an digital filter (16) with a set of factors changeable in time. The various sets of factors of the filter are selected so that the transmission characteristic of the filter (16) for the individual factors substantially correspond to the inverse frequency spectrum of the spatial intensity distribution of the transmitted beam (8) at different distances from the device (1).