| 摘要 |
PURPOSE:To improve reliability, by arranging magnetic pieces in parallel with a running path of a moving body at an equal distance, turning light, which is imparted through an optical fiber and the like on the moving body, by a magnetic field, dividing the light into two components, and supplying the light beams by other optical fibers as specified. CONSTITUTION:Magnetic pieces 10 are arranged in parallel with a running path of a moving body 1 at an equal distance P. On the moving body 1, an optical position detector 7, a magnetic field sensor 8, and a multiple-core optical fiber code 9 are mounted. Light from the detector 7 is made to be the light having only one polarized plane by a polarizing prism 82a through an optical fiber 9c of the cord 9, a right angle prism 81a of the sensor 8, and the like. The polarized plane is turned by a Farady element 83 by an angle proportional to a magnetic field H of the piece 10. The light is divided into the two components, whose polarized planes form a right angle. The light beams are inputted to the detector 7 through optical fibers 90a, 90b, and the like, and signals Va and Vb are obtained. The signals are applied to a differential amplifier 74. The position pulses are counted by a counter 75. |
