| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an objective lens for an optical pickup and an optical pickup device which can form a satisfactory spot by suppressing spherical aberration in recording or reproducing of the information with respect to either of an existing optical disk and an optical disk of a new specification. <P>SOLUTION: This objective lens for the optical pickup is used for the optical pickup device for recording or reproducing the information by selecting and using three kinds of light beams for a plurality of optical disks. In the optical pickup device, when a nearly parallel light beam is incident on the objective lens as to the light beam of a 1st wavelength and a divergent light beam is incident to the objective lens as to the light beams of 2nd and 3rd wavelengths, following equations (1) to (3) are satisfied on the condition that image formation magnifications in recording or reproducing the information with respect to each of the 1st to 3rd optical disks are expressed as M1 to M3, respectively, and focal distances are expressed as f1 to f3, respectively. (1) -0.02<f1×M1<0.02, (2) -0.10<f2×M2<-0.04 and (3) -0.29<f3×M3<-0.19. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
