| 摘要 |
PURPOSE:To perform stable servo by dividing into two equal parts with a dividing line parallel to the chord of a reflected light from a disk and, at the same time, extending another dividing line which is normal to the dividing line from the center position of the dividing line obtained by dividing the dividing line into two equal parts to the arc side of the reflected light. CONSTITUTION:A dividing line A is parallel with a reflected light from a disk which is made to have a semicircular shape by a knife edge, namely with the chord P1 of the light receiving pattern P of an optical sensor 10 and divides the optical sensor 10 into two equal parts. Moreover, another dividing line B which is normal to the dividing line A is extended from the center of the dividing line A to the arc P2 side of the light receiving pattern P. In such a constitution, stable servo can be performed since the offset point of the servo can be limited to one. |
