| 摘要 |
PCT No. PCT/JP96/03511 Sec. 371 Date Aug. 8, 1997 Sec. 102(e) Date Aug. 8, 1997 PCT Filed Nov. 29, 1996 PCT Pub. No. WO97/22008 PCT Pub. Date Jun. 19, 1997A rotation stopped detection sensor detects a rotation stopped condition of a rotatable body using a plurality of optical sensors. The detection sensor also includes a rotation disk having optical guide portions for guiding light beams from light emitting devices to respective light receiving devices, and light shut off portions for shutting off the light beams to the respective light receiving devices. The optical guide portions and the light shut off portions are disposed alternately on an outer peripheral portion of the rotation disk. The plurality of optical sensors are disposed such that when the disk is stopped, one of the optical sensors is always at a position corresponding to an optical guide portion. As a result, when the disk is stopped, there is always one output from the optical sensors which is at a high level. Hence the stopping of the disk can be advised using a direct output from the optical sensor.
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