| 摘要 |
PURPOSE:To obtain a small acceleration sensor with limited power consumption while serving as telemeter by providing a comb-shaped electrode on the surface of a piezo-electric substrate to form a surface acoustic wave element and arranging a load appyling means so that a load is applied on the element as uniform stress with an acceleration to be measured. CONSTITUTION:A bomb-shaped electrode 2, an input terminal 3 and an output terminal 4 are provided on a piezo-electric substrate 1 to form a surface acoustic wave (SAW) element. A SAW generated on the surface of the substrate 1 by a signal from the input terminal 3 is reflected sequentially with the comb-shaped electrode 2 and an output appears at the output terminal 4. When a bending load is applied to an SAW element 10, the series resonance frequency, parallel resonance frequency and passage characteristic changes due to a pitch variation and hence, acts as acceleration sensor. An acceleration generating mass 11 is mounted closer to both ends of the SAW element 10 supported at both ends thereof and a 4-point bending method is used to apply a uniform stress thereon. This provides a small acceleration sensor with limited power consumption while serving as telemeter. |
