| 摘要 |
PURPOSE:To reproduce a signal even if a recording pit is small and to set a reproduction error to be small even if the pit is sufficiently large by delaying the detection signal of reflected light in a preceding light spot between two optical spots. CONSTITUTION:Out of laser beams from a semiconductor laser 1, the light flux of P-polarized light which does not pass through a phase filter 8 converges a first light spot on an optical axis, and the light flux of S-polarized light which passes through the phase filter 8 converges second and third spots. Then, an information storage carrier 14 is irradiated with light flux. The reflected light of second and third light flux is detected in a photodetector 18 and a differential amplifier 20 detects differential output and reproduces the output signal. At that time, the detection signal of the photodetector 18 detecting the reflected light of the preceding optical spot is delayed for prescribed time by a delay circuit 19 and it is inputted to the differential amplifier 20. Thus, the width of a dark line existing between the two spots can be set to almost zero. |
