Information reading system with controlled optical access

Abstract

There is provided an improved information reading system, comprising: an objective lens for converging a reading beam on an information recording medium so as to form an information detecting point; an actuator for controlling the position of the information detecting point by driving the objective lens; a tracking error signal generator for generating a tracking error signal; a least one light detecting/receiving means having at least two light detecting/receiving sections for detecting and receiving light reflected from the information recording medium; a least one calculator connected with the at least one light detecting/receiving means for producing a difference signal indicating a difference between two light receiving amounts on the two detecting/receiving sections; a low frequency signal detecting/passing means for detecting and passing low frequency signals which are low frequency components contained in the difference signal; an adder for adding together the low frequency signals fed from the low frequency signal detecting/passing means and the tracking error signal; and a driver for driving the actuator in accordance with an output signal fed from the adder.