| 摘要 |
PURPOSE: To substantially reduce the side robe of a light spot due to a super resolution effect by inserting a phase filter into an incident light path to control light to be circular and detecting reflected light flux from a recording medium by dividing the reflected light in a specified manner. CONSTITUTION: The optical disk 8 is irradiated with a laser beam from a semiconductor laser 1, a reflective beam is detected by light detectors 13a and 13b and differential-processed and a reproducing signal is formed. A phase filter 24 having a super resolution effect for controlling the transparency of the incident beam in a circular center part is inserted to the incident light path, the transparency of the center circular areas 131 of the detectors 13a and 13b are set lower than that of edge part areas 132 and side robes often produced in the area 13a reducing resolution due to crosstalk are substantially reduced. Thus, with resolution substantially increased, the recording information of a highly dense recording disk is reproduced keeping good S/N. |
