| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical sensor in which a quarter wave plate surely converts linearly polarized light into circularly polarized light to secure and maintain excellent sensor sensitivity even when a wavelength used by light source light fluctuates in an optical system in the optical sensor. <P>SOLUTION: The optical sensor 1 for vibration detection includes a light source 2, a polarization beam splitter 3, an objective lens 4, a wave plate unit 5, and two-dimensional image sensors 6 and 14. The wave plate unit is formed of an integral structure of the quarter wave plate 7 utilizing structural birefringence and a diaphragm 8 having a reflection surface. On the light-receiving surfaces 6a and 14a of the two-dimensional image sensors, circular beam spot shapes concentric and having different radii are made incident corresponding to the position of the reflection surface 8a of the diaphragm and, from an output signal, the area or the radius of the beam spot shape is measured to detects the position or the displacement magnitude of the diaphragm. <P>COPYRIGHT: (C)2012,JPO&INPIT |
