| 摘要 |
PROBLEM TO BE SOLVED: To eliminate the effect of the divergent angle of a light beam by providing the optical pickup with a light focusing means for converging the light beam emitted from a light source by an aperture and focusing this light onto the signal recording surface of an optical disk and forming this aperture to an elliptic shape having the optical axis of this light focusing means at its center. SOLUTION: The light beam from a semiconductor laser element 21 is cast via respective optical elements 22 to 25 to the optical disk, is converged by the aperture 26a and is focused to the signal recording surface of the optical disk by an objective lens 26. The return light beam thereof is detected by a photodetector 29 via the respective optical elements and recording signals are reproduced. The aperture 26a formed to the elliptic shape converges the light beam by the minor diameter and major diameter with respect to the directions A and B of the small and large divergent angles of the light beam. Then, a uniform light intensity distribution is obtd. together with respect to the directions A, B. As a result, good reading performance is obtd. and the output coupling efficiency of the semiconductor laser element 21 is improved. |
