| 摘要 |
PURPOSE:To obtain an optical displacement sensor which is reducible in size and has a lens means by using a small-sized Fresnel lens. CONSTITUTION:An optical fiber 1 is fitted to a substrate 2 so that an end surface of the optical fiber contacts a half-mirror 2b. Part of light propagated in the fiber 1 is reflected by the mirror 2b and returns to the inside of the fiber 1 as irradiation light. Light transmitted through the mirror 2b, on the other hand, travels in the substrate 2, but made parallel by a lens 2a and projected from the lens to travel toward a body to be measured or a mirror 3 fitted thereto. Its reflected light is converged 2a and incident on the fiber 1. This light is used for reference measurement. The reference light and measurement light interfere with each other in the process of returning in the fiber 1 and interference light on which intensity modulation is imposed at the position of the mirror 3 is obtained at the other end and analyzed to measure the quantity of displacement of the mirror 3. The small-sized Fresnel lens is used, so the small-sized optical displacement sensor is obtained.
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