| 摘要 |
PURPOSE:To form a small photoelectric type rotary encoder having high resolving power, by applying the theory of a phase modulation detecting system. CONSTITUTION:A reflector disc 5 eccentric to the revolving center of a rotary shaft 10 protruded into an enclosure 20 is secured to the end part of said shaft 10 through a holding disc 11 while light emitting and receiving bodies 1-4 are fixed to the inner surface of the front wall of the enclosure 20 at the positions of mechanical angles alpha1-alpha4 appropriately selected relative to different quadrants on the circumference of a circle concentric to the shaft 10. Therefore, opposed areas of the light emitting and receiving bodies 1-4 and the reflector disc are changed corresponding to the revolving angle of the shaft 10 and the light emitting parts of the light emitting and receiving bodies 1-4 are lighted and controlled by sine wave drive signals of respective phase angles alpha1-alpha4 from a lighting control part 30. By this mechanism, the synthesized light amount of each light emitting and receiving body and the light receiving part has phase- shift corresponding to the revolving angle of the rotary shaft. By this method, a small optical type rotary encoder having high resolving power can be formed. |
