| 摘要 |
<p>PURPOSE:To reduce the cost of the whole device by providing plural photosensor pats containing an LED and one end of an optical fiber, and allowing the other end of plural optical fibers to oppose to one photodetector. CONSTITUTION:Plural photosensor parts are constituted of LEDs 1, 2 and 3, and one end of optical fibers 6, 7 and 8. One photodetector PD1 is opposed to and placed at the other end of the optical fibers 6, 7 and 8. A microcomputer IC1 outputs pulse signals S0-S2 and turns on the LEDs 1-3 to match a timing by which a subject passes through the photosensor part. An output of the photodetector PD1 at that time is inputted to a microcomputer IC2 through an operational amplifier IC2, and whether the subject has passed through the photosensor part or not is discriminated. In such a way, as for the photodetector PD1, one piece will suffice, and the cost of the whole device can be reduced.</p> |
