Optoelectronic device for recognizing contrast marks

摘要

PCT No. PCT/EP95/00992 Sec. 371 Date Dec. 21, 1995 Sec. 102(e) Date Dec. 21, 1995 PCT Filed Mar. 16, 1995 PCT Pub. No. WO95/29457 PCT Pub. Date Nov. 2, 1995An optoelectronic device for identifying a mark having a defined contrast pattern includes a transmitting element for emitting a beam of transmitted light. A deflector unit periodically guides the transmitted light beam over the mark. A receiving element receives the transmitted light beam after being reflected by the mark and produces an analog received signal which exhibits an amplitude modulation impressed by the contrast pattern of the mark and is dependent on the spatial intensity distribution of the transmitted light beam. An n-bit analog-digital converter has a word width greater than 1 for converting the analog received signal into a digital received signal. A digital filter includes an input for receiving the digital received signal. The digital filter has different coefficient sets that are temporally changed, wherein the coefficients of each coefficient set are selected so that a transmission characteristic of the filter for each coefficient set essentially corresponds to an inverse of the frequency spectrum of the spatial intensity distribution of the transmitted light beam at a respectively different distance from the device.