| 摘要 |
PROBLEM TO BE SOLVED: To accurately detect an angular position of a rotating object without error without expensive intrinsic bearing, by providing a correcting means for generating an output signal for removing an error generated by a discordance between a rotary shaft of the object and a shaft to be measured of a measuring scale. SOLUTION: A rotary shaft 51 for measuring an angular position is supported rotatably around an axis R merely in a bearing belonging to a rotary base. Many scanning units 2 each for photoelectrically scanning a housing 1 and a measuring scale 4 by transmitting lights belong to a static structure unit connected to a static portion 50 of the base. The units 2 output many partial scan signals depending upon angular positions to scan a rotary measuring scale at different many measuring scale positions. In the unit 2, a light source 2.1, a collimator 2.2 and a detecting element 2.3 having a scanning scale 4 are provided as a photoelectric transmission system. The selected scanning unit functions as a correcting means for generating an angular position measured position having as less eccentric error as possible. |
