| 摘要 |
PROBLEM TO BE SOLVED: To provide an electrostatic encoder capable of accurately detecting a rotational angle of a rotator based on change in electrostatic capacity between electrodes in a stator and the rotator.SOLUTION: The electrostatic encoder includes alternate arrangement of detection electrodes 44a to 44d and transmission electrodes 45a to 45d in a stator 41 in the circumferential direction. This alternate arrangement provides amplitude modulation from adjacent detection electrodes based on the rotation of a rotator 42 and output of detection signals (A-phase and B-phase) with a phase difference of 90°. The detection signals with the phase difference of 90°are modulated so that modulation signal V1 and V2 are generated. Application of resolver digital (RD) converting processing to the modulation signals can obtain a rotational angle of the rotator. Since the transmission electrodes and the detection electrodes are alternately arranged, it becomes possible to suppress unevenness of displacement of the modulation signals and decrease the number of detection electrodes, thereby achieving reduction of size of the electrostatic encoder.SELECTED DRAWING: Figure 4 |
