| 摘要 |
PURPOSE:To enable to narrow a gap between optical fibers and improve a SN ratio, by a method wherein a jetting end surface of an optical fiber, whose one end is connected to a light source, is caused to rock following rotation of a rotary body. CONSTITUTION:Under a condition that a rotary body is brought to a stop, a permanent magnet 22 is sucked by a magnetic pole of a disc 30, and an optical fiber 4 is bent centering around a fulcrum in the proximity of a fixed jig 24, whereby light from a light source is totally reflected at an interface between the core of the optical fiber and a clad, and a given volume of light is transferred to an optical fiber 6. Meanwhile, when the rotary body starts to turn, the disc 30 turns following rotation of a shaft 28, a jetting end surface 4a of the optical fiber 4 is caused to rock centering around a fulcrum, and an aggregate area of the jetting end surface 4a and an incident end surface 6a changes. As a resut, a light volume, transferred from the optical fiber 4 to the optical fiber 6, changes, and thereby a counting value proportioning the number of revolutions of the rotary body can be obtained by counting the number of changing times of the light volume. |
