| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical pickup device and an objective lens that can be used in common on the different optical information recording media, such as CD and DVD, which can suppress phase shift of wave aberration. SOLUTION: When a diffraction ring is brazed for the wavelength λ0 at the center and periphery of an objective lens, the wave aberration grows also in the periphery because of the ring. The phases of the wave aberrations, however, in the periphery and the center can be made substantially equal. Thus, the phase shift can be made zero or less than 0.05 λ1 by making the wave aberrations equal in average and the wave aberration can be improved. |
