Electrostatic-capacity-type acceleration sensor and acceleration measuring device therewith
First Claim
1. An acceleration measuring device comprising:
- an electrostatic-capacity-type acceleration sensor including a first capacitance detector having plural pairs of moving electrodes and fixed electrodes, which are arranged to face each other on a substrate surface such that facing areas therebetween are varied in response to an input acceleration, and a second capacitance detector having plural pairs of moving electrodes and fixed electrodes, which are arranged to face each other on the substrate surface such that facing areas therebetween are varied in response to the input acceleration and are set to be larger than the facing areas between the moving electrodes and the fixed electrodes of the first capacitance detector when the input acceleration is zero;
a first detection circuit for producing a first acceleration signal in response to capacitance variation occurring between the moving electrodes and the fixed electrodes of the first capacitance detector;
a second detection circuit for producing a second acceleration signal in response to capacitance variation occurring between the moving electrodes and the fixed electrodes of the second capacitance detector; and
a selector for selectively outputting the first acceleration signal as long as the first acceleration signal does not exceed a threshold level determined in advance and for selectively outputting the second acceleration signal when the first acceleration signal exceeds the threshold level.
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Accused Products
Abstract
A moving member having a plurality of moving electrodes is supported by support members at both ends thereof on a substrate surface in such a way that it can be subjected to displacement in a two-dimensional plane. A plurality of fixed electrodes are arranged to face the plurality of moving electrodes respectively, thus forming different facing areas therebetween when an input acceleration is zero. The facing areas formed between pairs of the electrodes facing each other are varied in response to the displacement of the moving member, whereby a capacitance caused by one pair of the electrodes whose facing area is relatively small is used to detect a relatively small input acceleration, and a capacitance caused by the other pair of the electrodes whose facing area is relatively large is used to detect a relatively large input acceleration.
15 Citations
4 Claims
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1. An acceleration measuring device comprising:
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an electrostatic-capacity-type acceleration sensor including a first capacitance detector having plural pairs of moving electrodes and fixed electrodes, which are arranged to face each other on a substrate surface such that facing areas therebetween are varied in response to an input acceleration, and a second capacitance detector having plural pairs of moving electrodes and fixed electrodes, which are arranged to face each other on the substrate surface such that facing areas therebetween are varied in response to the input acceleration and are set to be larger than the facing areas between the moving electrodes and the fixed electrodes of the first capacitance detector when the input acceleration is zero; a first detection circuit for producing a first acceleration signal in response to capacitance variation occurring between the moving electrodes and the fixed electrodes of the first capacitance detector; a second detection circuit for producing a second acceleration signal in response to capacitance variation occurring between the moving electrodes and the fixed electrodes of the second capacitance detector; and a selector for selectively outputting the first acceleration signal as long as the first acceleration signal does not exceed a threshold level determined in advance and for selectively outputting the second acceleration signal when the first acceleration signal exceeds the threshold level. - View Dependent Claims (2, 3, 4)
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Specification