| 摘要 |
PROBLEM TO BE SOLVED: To provide a chromatic aberration correcting optical system capable of reducing chromatic aberration caused in an objective lens even though the wavelength of a laser beam is varied for reducing laser noise in an optical pickup for performing recording and reproducing by the irradiation of the laser beam on an optical recording medium such as an optical disk. SOLUTION: A lens 10 for chromatic aberration correcting is constituted of two lenses of a first lens 11 which has a planar surface on a semiconductor laser 3 side and which has positive refracting power and a second lens 12 which has the planar surface on an objective lens 7 side, which is stuck to the lens 11, and which has negative refracting power. Since the lens 10 does not have power as a whole, the lens 10 has general applicability, so that the lens 10 can be applied to any kinds of the lens 7, and the optical pickup 1 which is simple, inexpensive, and has little chromatic aberraction position can be obtained. |
