| 摘要 |
PURPOSE:To improve the detecting accuracy of a rotation controller by mounting a rotary plates, on which a plurality of diffraction gratings are annularly arranged at a uniform interval, on a motor shaft, providing a light emitting element and a photoreceptor at one side, receiving the reflected light by the photoreceptor, thereby controlling the rotation. CONSTITUTION:Set number of diffraction gratings 12 which are formed in phase type and annularly arranged at uniform interval are provided on the outer periphery of a rotary plate 11, and mounted on a rotational shaft of a master disk rotating motor 17. A light emitting element and a photoreceptor are integrated as a light emitting and receiving element 18, which is disposed at the position opposed to the diffraction gratings 12, the reflected light from the grating 12 is received by the photoreceptor, the output is compared with a reference pulse 24, an error voltage is inputted to a control signal generator 26 and a drive circuit 27, thereby controlling a motor 17. Accordingly, the gratings 12 are processed in high accuracy, the detector is disposed at one side to reduce the space, and readily regulated. |
