Dynamic quantity sensor having movable and fixed electrodes with high rigidity
First Claim
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1. A dynamic quantity sensor comprising:
- a base portion;
a weight portion supported by the base portion to be displaced by a dynamic quantity applied thereto;
a movable electrode integrally formed with the weight portion and protruding from the weight portion; and
a fixed electrode protruding from the base portion and defining a detection interval with the movable electrode, the detection interval being changed by displacement of the weight portion to change a capacitance between the movable electrode and the fixed electrode for detecting the dynamic quantity, wherein;
at least one of the movable electrode and the fixed electrode has a tapered plane shape, a width of which decreases from a root portion toward a tip portion of the one of the movable electrode and the fixed electrode.
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Abstract
A dynamic quantity sensor has a weigh portion that is supported by a base portion to be displaced by a dynamic quantity, a movable electrode protruding from the weigh portion, and a fixed electrode protruding from the base portion and defining a detection interval with the movable electrode. The detection interval changes in response to displacement of the weight portion for detecting the dynamic quantity. Each of the movable electrode and the fixed electrode has a tapered plane shape with a width that decreases from a root portion toward a tip portion thereof.
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Citations
19 Claims
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1. A dynamic quantity sensor comprising:
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a base portion;
a weight portion supported by the base portion to be displaced by a dynamic quantity applied thereto;
a movable electrode integrally formed with the weight portion and protruding from the weight portion; and
a fixed electrode protruding from the base portion and defining a detection interval with the movable electrode, the detection interval being changed by displacement of the weight portion to change a capacitance between the movable electrode and the fixed electrode for detecting the dynamic quantity, wherein;
at least one of the movable electrode and the fixed electrode has a tapered plane shape, a width of which decreases from a root portion toward a tip portion of the one of the movable electrode and the fixed electrode. - View Dependent Claims (2, 3, 4)
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5. A dynamic quantity sensor comprising:
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a base portion;
a weight portion supported by the base portion to be displaced by a dynamic quantity applied thereto;
a movable electrode integrally formed with the weight portion and protruding from the weight portion; and
a fixed electrode protruding from the base portion and defining a detection interval with the movable electrode, wherein;
the dynamic quantity is detected based on a change in capacitance of the detection interval between the fixed electrode and the movable electrode while applying, to the fixed electrode and the movable electrode, carrier wave signals that periodically change with a carrier wave frequency, the carrier wave frequency being shifted from 1/n of a natural frequency of the fixed electrode when the fixed electrode performs flexural vibration, in which n is a positive integer. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12, 13)
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14. A dynamic quantity sensor comprising:
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a base portion;
a weight portion supported by the base portion to be displaced by a dynamic quantity applied thereto;
a movable electrode integrally formed with the weight portion and protruding from the weight portion; and
a fixed electrode protruding from the base portion and defining a detection interval with the movable electrode, the detection interval being changed by the displacement of the weight portion to change a capacitance between the fixed electrode and the movable electrode for detecting the dynamic quantity, wherein;
each of the movable electrode and the fixed electrode has a root portion and a tip portion in a protruding direction thereof, the root portion having a rigidity larger than that of the tip portion. - View Dependent Claims (15)
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16. A dynamic quantity sensor comprising:
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a base portion;
a weight portion supported by the base portion to be displaced by a dynamic quantity applied thereto;
first and second movable electrodes integrally formed with the weight portion and protruding from the weight portion; and
first and second fixed electrodes protruding from the base portion and respectively defining first and second detection intervals with the first and second movable electrodes, wherein;
first and second carrier wave signals having a first carrier wave frequency are respectively applied to the first and second fixed electrodes for detecting the dynamic quantity;
third and fourth carrier wave signals having a second carrier wave frequency are respectively applied to the first and second fixed electrodes for performing self-diagnosis; and
the first carrier wave frequency and the second carrier wave frequency are shifted from 1/n of a natural frequency of each of the first and second fixed electrodes when the first and second fixed electrodes perform flexural vibration, in which n is a positive integer. - View Dependent Claims (17, 18, 19)
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Specification