| 摘要 |
PURPOSE:To obtain the encoder which has environment resistance and high reliability by emitting and photodetecting light through optical fiber cables and installing the optical fiber cables in the mechanism part of the encoder opposite to each other across a rotary disk. CONSTITUTION:Projection light beams of LEDs 33 and 33' are projected on a signal processing circuit 30 from tip parts 7 and 8 of optical fiber cables 15 and 16 through the fiber cables 15 and 16. Then, photodiodes 34 and 36 are provided to convert photoelectrically light beams which are transmitted through the transmission part of the rotary disk 6 and photodetected at tip parts 9 and 10 of the cables. Their output signals are passed through amplifying circuits 35 and 37 to which resistances and transistors are connected and variation of every pitch of the rotary disk 6 is outputted as a pulse signal on the basis of an A-phase signal SB and a B-phase signal SB which is 90 deg. out of phase with the signal SA. Consequently, the direction and speed of rotation are obtained, the power consumption is small, and the maintainability is improved.
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