| 摘要 |
<P>PROBLEM TO BE SOLVED: To reduce a cost by reducing the number of at least one of light-emitting parts and light-receiving parts, in an encoder for detecting both the rotation angular speed and the reference position. <P>SOLUTION: The encoder is provided with a rotation pulse reflecting band 109 for alternately radially forming a plurality of high reflecting parts 111 and low reflecting parts, along the circumferential direction on one face of a disk 102, and a reference mark reflecting band 110, comprising a high-reflection part 112 formed at a part on a circumference different in it and the radial direction and a low reflecting part other than this. In the encoder processes of irradiating a rotation pulse reflecting part 109 with an optical beam, irradiated from the light-emitting part 103 by an optical system member 104, comprising two half-mirrors 113 and 114, branching the reflection light into a first reflected light and a second reflected light, irradiating the reference mark reflecting part 110 with second reflected light, receiving the first reflected light with a first light-receiving part 105 and receiving the reflected light from the reference mark reflected part 110 with a second light-receiving part 106 are included; as well as, detecting the rotation pulse signal from the light-receiving signal of the first light-receiving part 105 and detecting the reference mark signal from the light-receiving signal of the second light-receiving part 106. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
