| 摘要 |
PURPOSE:To facilitate the leading-out of a signal for detecting the distance from an irradiation part, e.g. the leading-out of a servo signal for focusing control of light irradiation to the irradiation part. CONSTITUTION:The equipment is provided with the following; an irradiation part 2, an optical element 21 having a light emitting part 1 and a first light receiving part 41, at least a second light receiving part 42 and a third light receiving part 43 which put the optical element 21 between them and are arranged on both sides of the element 21, and a covergent means 3. The first light receiving part 41 is arranged in the vicinity of the light emitting part 1, and receives the return light LR of the emitted light from the light emitting part 1 which return light travels from the irradiation part 2 toward the light emitting part 1. The second light receiving part 42 and the third light receiving part 43 are arranged step-wise in the manner in which one of the distances between the light receiving surfaces of the parts 42, 43 and the irradiation part 2 is large and the other is small as compared with the distance between the light receiving surface of the first light receiving part 41 and the irradiation part 2. |
