| 摘要 |
<P>PROBLEM TO BE SOLVED: To ensure and keep the good sensitivity of a sensor, by a one-quater wavelength plate which certainly converts linear polarized light into a circular polarized, even if the use wavelength of light source light in an optical system of an optical sensor is varied. <P>SOLUTION: A vibration detecting optical sensor 1 comprises a light source 2, a polarized light beam splitter 3, an objective lens 4, a wavelength plate unit 5, and one light receiving element 6. The wavelength plate unit has an integrated structure of a one-quater wavelength plate 7 using structural birefringent and a vibration plate 8 having a reflecting surface. The light receiving element is disposed so as to make its optical axis x2 in parallel with and slightly shift from an optical axis x1 of reflection light, and an incident beam spot shape is projected at a position where its center c is slightly shifted from a center O of a light receiving surface 6a, so that detected light amount is increased and decreased according to the displacement of the vibration plate. <P>COPYRIGHT: (C)2012,JPO&INPIT |
