APPARAT FOR AVLESNING AV EN OPTISK STRALNINGSREFLEKTERANDE UPPTECKNINGSBERARE

摘要

An apparatus is described for reading an optical radiation-reflecting information carrier, which apparatus comprises an opto-electronic focussing error detection system. The radiation path of the read beam which is directed towards the information carrier includes a radiation deflecting element. The focussing beam which is derived from the radiation beam by said element co-operates with two focussing detectors, the difference between the output signals of the focussing detector being determined by the degree of focussing of the read beam on the information structure.