Track searching arrangement for an optical information recording and reproducing apparatus.

摘要

A track searching system for an optical information recording and reproducing apparatus in which a disc-like information carrier (5) provided previously with concentric or spiral guide tracks (8, 30) of a channel-like configuration is used as an information recording and storing means and adapted to be scanned by a light beam (2) for recording or retrival of information. Light flux (11, 17b) reflected by the information carrier (5) and presenting variable distribution of light intensity (Figures 3; 17b) is received by paired photoelectric elements (19a, 19b). A difference signal (23) and a sum signal (28) derived from the output signals from the photoelectric elements (19a, 19b) or a reproduced RF signal representative of reproduced information undergo phase comparison processing (at 25), the result of which is utilized for determining the direction in which the guide track (8, 30) is traversed by the scanning light beam (2) and the number of tracks which have been traversed by the light beam. A desired track (57) is thus searched and accessed with high accuracy at a high speed for assuring a positive and rapid information recording or retrieval at the desired track regardless of eccentricity (A) of the information carrier, variations in the scanning speed and the presence of recorded track (103).