PURPOSE: To detect a distortion by a simple constitution, by detecting a variation of light which has been generated by the distortion, as a frequency signal.
CONSTITUTION: When a pressure receiving element 1 receives a pressure (p) from the direction as indicated with an arrow, its thin wall part 1b is displaced. A light emitting element 2a, and the element 2b are fixed to a thick wall part 1a, and extending over the thin wall part 1b and the thick wall part 1a, respectively, and forward voltage is impressed to them in advance. When a pressure is applied to the element 1, the thin wall part 1b is distorted, and a frequency of the light of the element 2b is varied. The varied frequency, and a frequency of the element 2a to which no distortion is applied are inputted to an optical interference means 4 through glass fibers 3a, 3b. Two beams of light are made to interfere and detected, and a distortion is calculated by an operator 5. According to the constitution of this circuit, since an output signal is fetched as light. The coupling to a computer, etc. is performed easily, also, no noise is picked up in the course of a transmission, and a distortion whose S/N is excellent can be detected.
IKEDA KYOICHI
WATANABE TETSUYA
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