| 摘要 |
PROBLEM TO BE SOLVED: To obtain an optical pickup of double foci for a 0.6mm disk and a 1.2mm disks. SOLUTION: This optical pickup has a hologram lens 26 for diffracting the light from a light source in order to enhance the efficiency of light and to lessen the influence of the fluctuation of an optical axis and an objective lens 27 for focusing the +1st order diffracted beam of the hologram lens 26 to a thin disk 21 and focusing the -1st order diffracted beam to a thick disk 22. Namely, the degradation in the light efficiency is prevented by simultaneously using the fist order diffracted beam and the -1st order diffracted beam by the hologram lens 26. The production and assembly are facilitated and the optical performance stable against the fluctuation of the optical axis is exhibited by using the simple rigged hologram lens 26. |
