OPTICAL SENSOR

摘要

PURPOSE:To simplify constitution and to enhance temp. stability by providing a reflecting body bending a light path by 45 deg. on the way of the light paths of input and output collimator lenses CL and allowing the polarizing directions of the emitting beams from a polarizer and a detector to cross each other at a right angle. CONSTITUTION:The beam becoming parallel by an input CL 5a becomes transmitted linear polarized beam and reflected linear polarized beam crossing each other at a right by a polarizer 5b. The beam path of the transmitted liner polarized beam is converted by 90 deg. by a triangle prism 7 and said polarized beam is allowed to be incident to an optical axis at an angle of 45 deg. by a 1/4 wavelength plate 5c to be converted to circular polarized beam which is, in turn, emitted to an electro-optical crystal element 5d. The circular polarized beam incident to the element 5d is modulated in phase by the voltage applied to the element 5d to become oval polarized beam which is, in turn, inputted to an analyzer 5e to become transmitted linear polarized beam and reflected linear polarized beam crossing each other at a right angle and the reflected linear polarized beam is guided to an output CL 5f and the polarizing direction of the emitting beam of the polarizer 5b and that of the emitting beam of the analyzer 5e become a state crossing each other at a right angle. By this constitution, temp. stability becomes good and, since the respective optical fibers 55a, 55b of incident beam and emitting beam can be led out in the same direction or opposite directions, a structure becomes simple.