| 摘要 |
PROBLEM TO BE SOLVED: To increase a range of a detectable inclination angle when an inclination of a surface to be detected is detected, to assure linearity in the case of calculating the angle and to accurately detect the angle. SOLUTION: A gradient of a recording surface 20A of an optical disk 20 is detected. A light irradiated from an LED 12 is reflected on the surface 20A through a lens 18, its reflected light is condensed by the lens 18, and incident to PD 14A to PD 14P disposed in a matrix state of 4×4 as reflected spot light. The reflected spot light is detected by the PD 14A to PD 14P, and the inclination of the surface 20 is detected by the distribution of the receiving amounts of the PD 14A to the PD 14P. When the inclination is calculated from the amounts of the PD 14A to the PD 14P, a weight coefficient is multiplied and calculated for the detection of the PD far from a center of the light receiving range, and hence linearity of the detected output when the angle becomes large is assured, thereby detecting the accurate inclination angle.
|
