| 摘要 |
PURPOSE:To permit a differential spatial filter device of simple structure, which measures a velocity, etc., by using the optical irregularity of a body to be measured, to perform stable velocity measurement without any restriction even under strong electromagnetic induction, in a liquid, and in an explosive atmosphere, by arraying the photodetection ends of optical fibers in a line, and leading alternate optical fibers to two photodetectors. CONSTITUTION:The photodetection ends 14 of optical fibers 19 are arrayed in a line and alternate fibers are put together as a fiber bundle 16 and a fiber bundle 17. Incident light from a moving body is guided from alternate photodetection ends 14 through the fiber bundles 16 and 17 and added together by a photodetector, respectively. Therefore, this spatial filter device is utilized for the measurement of the velocity of the moving body, etc. Since this filter device has the simple and durable constitution and also handles light signals, so there is no influence of electromagnetically induced noise and the stable velocity measurement is carried out even under strong electromagnetic induction, in a liquid, and in an explosive atmosphere. |
