| 摘要 |
PURPOSE:To reduce the number of elements and the size of the titled detector by providing grooves corresponding to tracks on a base on the recording signal base and irradiating this each groove with light from the side by a light emitting and photodetecting it with photodetecting elements on the tracks. CONSTITUTION:The light emitted from the light emitting element 1 is made incident on the recording signal base 2 from the side and separated into the refracting light toward the upper tracks 6a, 6b...6f at a slanting surface 3a of six grooves 3a, 3b...3f in order and the light going straight ahead within the base 2. Then, when the position of the base 2 is the turning position in which a light shielding part 6s is formed on the tracks 6a, 6b...6f, since the light is intercepted by the light shielding part 6s, the light does not reach the photodetecting elements 5a, 5b...5f but when the light shielding part 6s is not formed conversely, the refracted light reach the elements 5a, 5b...5f. Then, at the time of this photodetecting, a photodetecting signal is outputted. Then, a signal with six bits is made by deciding the photodetecting state of the elements 5a, 5b...5f for six each track 6a, 6b...6f in total and the position of the base 2 can be detected.
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