| 摘要 |
PURPOSE:To obtain a pressure sensor which has high intensity and uses no metallic material by converting the deformation of a pressure receiving plate into variation in the capacity of a piezoelectric material and detecting variation in resonance frequency. CONSTITUTION:A bottom plate 1 and a side plate 2 are considered to be rigid bodies in terms of size and material as compared with a top plate 3. The top plate 3 is made thin to have flexibility and elasticity, and a proper material is selected for them. A hollow part 6 is made airtight. Piezoelectric elements 41 and 42 are fitted to the top plate 3 and used as resonance elements to constitute an electric resonance circuit. Then when external pressure varies, the top plate varies in the quantity of deformation and the piezoelectric elements 41 and 42 vary in electric capacity to vary the resonance frequency. Consequently, the pressure is measured by detecting the frequency.
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