| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical head device equipped with a converging device which secures a full optical strength at the time of recording and which forms an optical beam having a small beam spot diameter at the time of reproduction, and also to provide an optical disk device. SOLUTION: The optical head is equipped with a converging device 10 that makes the laser beam enter and that makes it exit with the spot diameter deformed, and equipped with a power supply device 28 that provides a power source for the converging device. The optical head characteristically changes the spot diameter of the laser beam, which is made incident on the converging device 10, by turning on or off the power supply device 28, forming a laser beam spot diameter smaller at the time of reproduction than at the time of recording. |
