| 摘要 |
PROBLEM TO BE SOLVED: To provide a displacement detector causing complex resonance even when the return distance from a light source to an object is longer than the coherence length of the laser light. SOLUTION: The device has a light source (laser light source 1) emitting a laser light, a first optical means (optical part 2) condensing the emitted laser light, a light introduction means (light introduction part 3) introducing the condensed laser light to an object capable of displacing, a second optical means (optical part 4) irradiating the object with the introduced laser light, a light receiving means (photodetector 6) outputting electric signal according to the light quantity due to complex resonance of the laser light reflected at the end surface of the object side of the light introduction means and the reflection light from the object, a control means (drive circuit 8) varying the wavelength of the laser light so that the phase difference between the laser light reflected at the end surface of the object side based on the detected light quantity and the reflection light from the object becomes constant, and a detecting means (control circuit 7) detecting the displacement of the object and/or displacement quantity based on the variation. COPYRIGHT: (C)2006,JPO&NCIPI
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