| 摘要 |
PURPOSE: To enhance the efficiency of light utilization, to improve the resolution of the information signal detection on an optical disk and to attain miniaturization. CONSTITUTION: This optical pickup has a concave lens 22 arranged in the optical path between a semiconductor laser 21 and an objective lens 25 and a photodetector 27 arranged near the condensing point where the reflected luminous flux from the optical disk 26 transmits the concave lens 22 and is condensed. The information signals recorded on the optical disk 26 are detected from the output signal of this photodetector 27. |
