| 摘要 |
PURPOSE: To provide an optical head device and the information recording and reproducing device to be capable of supplying a laser beam having stable light intensity. CONSTITUTION: For the optical head device 3, the output of a laser element 12 is maintained to be constant by a monitor laser beam returned on the side of a recording surface of an optical disk D by an APC mirror 18. Since the APC mirror is disposed to be inclined at a prescribed angle to an optical axis of this sytem, a laser beam to be reflected from the APC mirror 18 is only guided to an APC cell (2nd detector) 14b. Thus, the light intensity of the laser beam emitted from the laser element can accurately be detected, and the output of the laser element is maintained to be constant in light intensity. |
