| 摘要 |
PURPOSE: To increase durability by providing a light emitting means, a light receiving means, a shielding plate arranged in the optical path of a light made incident on the light receiving means from the light emitting means and a detecting means for detecting the steering angle of a steering wheel based on the output of the light receiving means. CONSTITUTION: When a movable part including a steering wheel is rotated relative to a car main body, a shielding plate 6 is rotated around a rotary shaft corresponding to the steering angle thereof. The shielding plate 6 includes four groups of photocouplers composed of light emitting diodes D2 to D5 and phototransistors TR2 to TR5 corresponding to annular slits 61. The phototransistors TR2 to TR output H level signals when lights from the corresponding light emitting diodes D2 to D5 are detected, and L level signals when no lights are detected. Thus, signals corresponding to the steering angle of the steering wheel are outputted to terminals T5 to T8, and a microcomputer 1 detects the steering angle based on 4 bit data from the terminals T5 to T8. |
