| 摘要 |
PURPOSE:To enhance the efficiency of utilizing the emitting light quantity of a light source and to obtain a spot which lessens inter-track interference by setting the numerical aperture on the light source side of a finite objective lens at a prescribed value. CONSTITUTION:The luminous flux from a semiconductor laser 100 is made incident through a hologram element 103 and the finite objective lens 10 on a magneto-optical disk substrate 106. The luminous flux is reflected by a recording layer 107 and is made incident on a unit 117 of a type integrated with an LP-PD-hologram, then arrives at photoelectric conversion elements 112, 113. The numerical aperture on the light source side of the lens 10 is set at >=0.08 to satisfy a standardized value of the emitting light quantity thereof. The good magneto-optical reproducing signals having the less inter-track interference are obtd. by setting the numerical aperture on the light source side at <=0.21. |
