| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical head capable of reproducing two optical disks with a different thickness, one with information recorded with higher density than in the present state and the other recorded with the conventional density. SOLUTION: In accordance with the difference in thickness of an optical disk, in an optical system that converges as a micro spot a beam outgoing from a semiconductor laser light source 2, the aberration due to the difference in thickness of the optical disk can be cancelled through the transfer in the direction of the optical axis of a collimator lens 4a and an objective lens 3 by a lens actuator 5a, 5b. In addition, another example is such that a second collimator lens is provided which cancels the aberration generating in a first collimator lens, as is an objective lens which corrects the aberration remaining in the first and the second collimator lens, and that the aberration can be cancelled which is due to the difference in thickness of the optical disk. |
