| 摘要 |
PURPOSE:To attain miniaturization by reducing the numbers of parts, by forming oblique surfaces each having a constant angle to both ends of the optical axis of a photoelastic effect element and providing a polarizer to one oblique surface while providing an analyser to the other oblique surface. CONSTITUTION:A photoelastic effect element 14 forms oblique surfaces so that both ends in an optical axis direction are almost 45 deg. to the optical direction and each of the polarizing member 15 provided to one oblique surface and the analyser member provided to the other oblique surface are formed in a plurality of layers in a membrane state having polarizing action. A wt. 17 is arranged to the photoelastic effect element 14 in parallel with the optical axis so as to equally apply strain to the optical axis while strain accompanied by vibration generated in an object 13 to be measured is applied to said element 14 and a double refraction phenomenon is generated between the polarizing member 15 and the analyser member 16 and phase difference is generated from light undulatory property. Light intensity is modulated according to vibration from this polarizing action. in a non-vibrated stationary state, because static strain is applied and phase difference is generated by anoperation theory, phase difference is changed around this state by vibration and optical bias is applied. |
