发明名称 |
Capacitive force-balance system for measuring small forces and pressures |
摘要 |
A force balancing method and apparatus detects small changes in force or pressure. An LC tuned circuit having a capacitor with at least one movable plate senses force or pressure changes. Deviations in the phase of the response of the tuned circuit are compared to the phase of a driving reference oscillator to generate an error signal. The error signal is used to control the oscillator to increase or decrease its output amplitude for driving the tuned circuit. As a result the electrostatic force across the capacitor plates tends to change in such a way as to precisely balance the effect of external force or pressure changes. The system therefore operates in a force-balance mode and in such a way as to provide a high sensitivity together with a precisely controlled stiffness. This system is particularly applicable to high sensitivity microphones, micro-topography, and atomic force microscopy.
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申请公布号 |
US5085070(A) |
申请公布日期 |
1992.02.04 |
申请号 |
US19900476865 |
申请日期 |
1990.02.07 |
申请人 |
AT&T BELL LABORATORIES |
发明人 |
MILLER, GABRIEL L.;WAGNER, ERIC R. |
分类号 |
G01B5/28;G01L1/08 |
主分类号 |
G01B5/28 |
代理机构 |
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代理人 |
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主权项 |
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地址 |
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