PURPOSE: To obtain a temperature sensor consisting of a small number of components without using any movable member by using a two-directional coil spring type optical fiber and pressing one optical fiber into a groove by the elastic force of the optical fiber itself.
CONSTITUTION: An optical fiber 11a is fixed in a V groove 12 and a fixation groove 18 provided slantingly except at its tip parts, and the fiber is pressed into the groove 12 by its own elastic force nearby its tip. Then, one terminal of torsional coil spring type two-directional shape memory alloy 15 is fixed to a main body 17 and the other end pushes up the fiber 11a above certain temperature. Consequently, the alloy 15 is to change its shape above the certain temperature and pressure the tip of the fiber 11a, so that the optical axes of the two optical fibers 11 are not aligned with each other any more. Further, when the temperature falls, the alloy 15 restores itself to its original shape and the optical axes of the fibers 11a and 11b are aligned with each other. Thus, light in the optical fibers is transmitted and intercepted about the certain temperature.
KURATA NOBORU
TOJO MASAAKI
Next Patent: OPTICAL TEMPERATURE SENSOR