| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical pickup in which good spot quality of both wavelengths can be obtain, and thinning and miniaturization can be realized even when a beam shaping prism is used in an optical system made an objective lens two-wavelength sharing using two light sources of different wavelengths. SOLUTION: In the optical system which made the objective lens 8 the two- wavelength sharing using a first module 1 at a side of a DVD, and a second module 13 for a CD with which the wavelengths differ, the CD side also obtains a good spot by providing with an AS correction prism 3 being an astigmatic correction means in an optical path only at the CD side to correct astigmatism which is generated when divergent light at the CD side passes to the beam shaping prism 6 used for the beam shaping at the DVD side. While the good spot is thereby obtained also for the DVD side and the CD side, the miniaturization and the thin shape of the optical pickup can be realized. |
