| 摘要 |
PURPOSE:To increase the number of recording bits and to improve the recording density by diminishing the light intensity in the vicinity of a center of a cross section of an outgoing beam when reflected light from a converging point as a microspot formed from the outgoing light from a laser light source is led to a photodetector. CONSTITUTION:When the outgoing light from a semiconductor laser 1 is condensed by a condenser lens 4 to be converged on a recording medium 5, a part of the outgoing light is reflected by a beam splitter 2 located usually between the laser 1 and a lens 3, and the intensity of the beam is detected by a regenerative signal detector 6. In this constitution, a light intensity distribution modulator 3 is newly inserted between the splitter 2 and the lens 4, so as to diminish the light in the vicinity of the center of a circular or ellipsoidal beam cross section. That is, the modulator 3 is specified as a transmission type, and in the vicinity of its middle part, an aluminum metal 62 finished with black dye for lowering the reflection intensity is provided to reduce the light intensity in the center part of the beam. By this method, the effect of the reflected light from the medium 5 is reduced to promote the recording density. |
