| 摘要 |
PROBLEM TO BE SOLVED: To exactly detect recording medium kinds by moving the entire lens block body in a focusing direction to vary the relative distance between an objective lens and an auxiliary lens and discriminating the presence or absence of the reflected light from the surface of the recording medium during the course of the movement as a first detection point and the presence or absence of the reflected light from a signal surface as a second by moving the entire lens block body. SOLUTION: The entire lens block body LB 1 is moved and the kind of an optical disk D which is the recording medium during the course of the movement is discriminated from the detection signal in accordance with the reflected light from the optical disk D by determining whether there is the reflected light from the surface d1 of the optical disk D or not as the first detection point and whether there is the reflected light from the signal surface d2 of the optical disk D or not as the second detection point. The signals of the reflected light from both of the surface d1 and signal surface d2 of the optical disk D are utilized and since the change in the reflected light at these points is distinct, the discrimination is made easier and the exacter discrimination is made possible. The discrimination time is shortened by the moving speed regulation of the discriminating means. |
