Dynamic amount sensor
First Claim
1. A dynamic amount sensor comprising:
- a frame having a hollow portion;
a plurality of flexible beams connected to the frame;
a mass supported on the frame by way of the flexible beams, a surface portion of the mass functioning as a movable electrode and changing an attitude thereof corresponding to an external force;
a plurality of fixed electrodes arranged to face the mass in an opposed manner;
detecting means for detecting a change in an electrostatic capacitance of each of a plurality of electrostatic capacitance elements comprised of the movable electrode and a respective fixed electrode;
switching means for switching the detecting means to a first connecting state forming a first detecting circuit that detects a change in the electrostatic capacitance of the electrostatic capacitance elements in accordance with a change in an attitude of the surface portion of the mass in a first detecting axis direction, and for switching the detecting means to a second connecting state forming a second detecting circuit that detects a change in the electrostatic capacitance of the electrostatic capacitance elements in accordance with a change in an attitude of the surface portion of the mass in a second detecting axis direction; and
dynamic amount outputting means for outputting, in accordance with a detection result by the detecting means in the first and second connecting states, components of a dynamic amount acting on the surface portion of the mass in the first detecting axis direction and the second detecting axis direction;
wherein the first detecting circuit includes a circuit formed by connecting at least a first electrostatic capacitance element in series with at least a second electrostatic capacitance element, the first and second electrostatic capacitance elements changing electrostatic capacitances along with an inclination of the mass in the first detecting axis direction such that when the electrostatic capacitance of the first electrostatic capacitance element increases the electrostatic capacitance of the second electrostatic capacitance element decreases;
wherein the second detecting circuit includes a circuit formed by connecting at least a first electrostatic capacitance element in series with at least a second electrostatic capacitance element, the first and second electrostatic capacitance elements of the second detecting circuit changing electrostatic capacitances along with an inclination of the mass in the second detecting axis direction such that, for the second detecting circuit, when the electrostatic capacitance of the first electrostatic capacitance element increases the electrostatic capacitance of the second electrostatic capacitance element decreases; and
further comprising carrier wave applying means for applying carrier waves whose phases are inverted from each other by 180°
to the respective first and second electrostatic capacitance elements which are connected in series in the first detecting circuit and the second detecting circuit.
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Accused Products
Abstract
A dynamic amount sensor has a detecting circuit that detects a change in an electrostatic capacitance of each of electrostatic capacitance elements comprised of a movable electrode and a fixed electrode. A switching circuit switches the detecting circuit to first and second connecting states that detect changes in the electrostatic capacitance of the electrostatic capacitance elements in accordance with a change in an attitude of the movable electrode in corresponding first and second detecting axes directions. In the first and second connecting states, the detecting circuit includes circuits formed by connecting the electrostatic capacitance elements in series which change electrostatic capacitances symmetrically along with inclination of the movable electrode in the corresponding first and second detecting axes directions. A carrier wave applying circuit applies carrier waves whose phases are inverted from each other by 180° to the electrostatic capacitance elements which are connected in series in the first and second connecting states of the detecting circuit.
17 Citations
18 Claims
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1. A dynamic amount sensor comprising:
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a frame having a hollow portion; a plurality of flexible beams connected to the frame; a mass supported on the frame by way of the flexible beams, a surface portion of the mass functioning as a movable electrode and changing an attitude thereof corresponding to an external force; a plurality of fixed electrodes arranged to face the mass in an opposed manner; detecting means for detecting a change in an electrostatic capacitance of each of a plurality of electrostatic capacitance elements comprised of the movable electrode and a respective fixed electrode; switching means for switching the detecting means to a first connecting state forming a first detecting circuit that detects a change in the electrostatic capacitance of the electrostatic capacitance elements in accordance with a change in an attitude of the surface portion of the mass in a first detecting axis direction, and for switching the detecting means to a second connecting state forming a second detecting circuit that detects a change in the electrostatic capacitance of the electrostatic capacitance elements in accordance with a change in an attitude of the surface portion of the mass in a second detecting axis direction; and dynamic amount outputting means for outputting, in accordance with a detection result by the detecting means in the first and second connecting states, components of a dynamic amount acting on the surface portion of the mass in the first detecting axis direction and the second detecting axis direction; wherein the first detecting circuit includes a circuit formed by connecting at least a first electrostatic capacitance element in series with at least a second electrostatic capacitance element, the first and second electrostatic capacitance elements changing electrostatic capacitances along with an inclination of the mass in the first detecting axis direction such that when the electrostatic capacitance of the first electrostatic capacitance element increases the electrostatic capacitance of the second electrostatic capacitance element decreases; wherein the second detecting circuit includes a circuit formed by connecting at least a first electrostatic capacitance element in series with at least a second electrostatic capacitance element, the first and second electrostatic capacitance elements of the second detecting circuit changing electrostatic capacitances along with an inclination of the mass in the second detecting axis direction such that, for the second detecting circuit, when the electrostatic capacitance of the first electrostatic capacitance element increases the electrostatic capacitance of the second electrostatic capacitance element decreases; and further comprising carrier wave applying means for applying carrier waves whose phases are inverted from each other by 180°
to the respective first and second electrostatic capacitance elements which are connected in series in the first detecting circuit and the second detecting circuit. - View Dependent Claims (2, 3, 4, 5, 6, 10, 11, 12, 13, 14, 15)
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7. A dynamic amount sensor according to 5;
- wherein the fixed electrodes include four first electrodes which, using a center position of mass as a reference position, are arranged equidistantly around the reference position on the same plane;
wherein the circuit of the first detection circuit includes first and second circuit portions connected in series, the first circuit portion being formed by connecting in parallel one of the electrostatic capacitance elements comprised of the movable electrode and a first of the four first electrodes positioned in a first quadrant on an x-y plane with one of the electrostatic capacitance elements comprised of the movable electrode and a second of the four first electrodes positioned in a second quadrant on the x-y plane, the second circuit portion being formed by connecting in parallel one of the electrostatic capacitance elements comprised of the movable electrode and a third of the four first electrodes positioned in a fourth quadrant on the x-y plane with one of the electrostatic capacitance elements comprised of the movable electrode and a fourth of the four first electrodes positioned in a third quadrant on the x-y plane;
wherein the circuit of the second detection circuit includes first and second circuit portions connected in series, the first circuit portion being formed by connecting in parallel the electrostatic capacitance element comprised of the movable electrode and the first of the four first electrodes positioned in the first quadrant on the x-y plane with the electrostatic capacitance element comprised of the movable electrode and the third of the four first electrodes positioned in the fourth quadrant on the x-y plane, the second circuit portion being formed by connecting in parallel the electrostatic capacitance element comprised of the movable electrode and the fourth of the four first electrodes positioned in the third quadrant on the x-y plane and the electrostatic capacitance element comprised of the movable electrode and the second of the four first electrodes positioned in the second quadrant on the x-y plane; and
wherein the switching means switches the first detection circuit and the second detection circuit by switching wire connecting states of the electrostatic capacitance elements.
- wherein the fixed electrodes include four first electrodes which, using a center position of mass as a reference position, are arranged equidistantly around the reference position on the same plane;
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8. A dynamic amount sensor according to 7;
- wherein the fixed electrodes further include four second electrodes on a plane which face the four first electrodes in an opposed manner by way of the mass;
wherein the circuit of the first detection circuit connects in parallel one of the electrostatic capacitance elements comprised of the movable electrode and a first of the four second electrodes positioned in the fourth quadrant on the x-y plane and one of the electrostatic capacitance elements comprised of the movable electrode and a second of the four second electrodes positioned in the third quadrant on the x-y plane with the electrostatic capacitance element comprised of the movable electrode and the first of the four first electrodes positioned in the first quadrant on the x-y plane, and connects in parallel one of the electrostatic capacitance elements comprised of the movable electrode and a third of the four second electrodes positioned in the first quadrant on the x-y plane and one of the electrostatic capacitance elements comprised of the movable electrode and a fourth of the four second electrodes positioned in the second quadrant on the x-y plane with the electrostatic capacitance element comprised of the movable electrode and the fourth of the first electrodes positioned in the third quadrant on the x-y plane; and
wherein the circuit of the second detection circuit connects in parallel the electrostatic capacitance element comprised of the movable electrode and the third of the four second electrodes positioned in the first quadrant on the x-y plane and the electrostatic capacitance element comprised of the movable electrode and the first of the four second electrodes positioned in the fourth quadrant on the x-y plane with the electrostatic capacitance element comprised of the movable electrode and the fourth of the four first electrodes positioned in the third quadrant on the x-y plane, and connects in parallel the electrostatic capacitance element comprised of the movable electrode and the second of the four second electrodes positioned in the third quadrant on the x-y plane and the electrostatic capacitance element comprised of the movable electrode and the fourth of the four second electrodes positioned in the second quadrant on the x-y plane with the electrostatic capacitance element comprised of the movable electrode and the first of the four first electrodes positioned in the first quadrant on the x-y plane.
- wherein the fixed electrodes further include four second electrodes on a plane which face the four first electrodes in an opposed manner by way of the mass;
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9. A dynamic amount sensor according to 7;
- wherein the fixed electrodes comprise a third electrode on a plane which face the first four electrodes in an opposed manner by way of the mass; and
wherein the third detecting circuit includes a circuit formed by connecting in series the electrostatic capacitance element comprised of the movable electrode and one of the four first electrodes and the electrostatic capacitance element comprised of the movable electrode and the third electrode.
- wherein the fixed electrodes comprise a third electrode on a plane which face the first four electrodes in an opposed manner by way of the mass; and
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16. A dynamic amount sensor comprising:
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a frame having a hollow portion; a plurality of flexible beams connected to the frame; a mass supported on the frame by way of the flexible beams, a surface portion of the mass functioning as a movable electrode and changing an attitude thereof corresponding to an external force; a plurality of fixed electrodes arranged to face the mass in an opposed manner; detecting means for detecting a change in an electrostatic capacitance of each of a plurality of electrostatic capacitance elements comprised of the movable electrode and a respective fixed electrode; switching means for switching the detecting means to a first connecting state forming a first detecting circuit that detects a change in the electrostatic capacitance of the electrostatic capacitance elements in accordance with a change in an attitude of the surface portion of the mass in a first detecting axis direction, and for switching the detecting means to a second connecting state forming a second detecting circuit that detects a change in the electrostatic capacitance of the electrostatic capacitance elements in accordance with a change in an attitude of the surface portion of the mass in a second detecting axis direction; and dynamic amount outputting means for outputting, in accordance with a detection result by the detecting means in the first and second connecting states, components of a dynamic amount acting on the surface portion of the mass in the first detecting axis direction and the second detecting axis direction; wherein the fixed electrodes include four first electrodes which, using a center position of mass as a reference position, are arranged equidistantly around the reference position on the same plane; wherein the circuit of the first detection circuit includes first and second circuit portions connected in series, the first circuit portion being formed by connecting in parallel one of the electrostatic capacitance elements comprised of the movable electrode and a first of the four first electrodes positioned in a first quadrant on an x-y plane with one of the electrostatic capacitance elements comprised of the movable electrode and a second of the four first electrodes positioned in a second quadrant on the x-y plane, the second circuit portion being formed by connecting in parallel one of the electrostatic capacitance elements comprised of the movable electrode and a third of the four first electrodes positioned in a fourth quadrant on the x-y plane with one of the electrostatic capacitance elements comprised of the movable electrode and a fourth of the four first electrodes positioned in a third quadrant on the x-y plane; wherein the circuit of the second detection circuit includes first and second circuit portions connected in series, the first circuit portion being formed by connecting in parallel the electrostatic capacitance element comprised of the movable electrode and the first of the four first electrodes positioned in the first quadrant on the x-y plane with the electrostatic capacitance element comprised of the movable electrode and the third of the four first electrodes positioned in the fourth quadrant on the x-y plane, the second circuit portion being formed by connecting in parallel the electrostatic capacitance element comprised of the movable electrode and the fourth of the four first electrodes positioned in the third quadrant on the x-y plane and the electrostatic capacitance element comprised of the movable electrode and the second of the four first electrodes positioned in the second quadrant on the x-y plane; and wherein the switching means switches the first detection circuit and the second detection circuit by switching wire connecting states of the electrostatic capacitance elements.
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17. A dynamic amount sensor according to 16;
- wherein the fixed electrodes further include four second electrodes on a plane which face the four first electrodes in an opposed manner by way of the mass;
wherein the circuit of the first detection circuit connects in parallel one of the electrostatic capacitance elements comprised of the movable electrode and a first of the four second electrodes positioned in the fourth quadrant on the x-y plane and one of the electrostatic capacitance elements comprised of the movable electrode and a second of the four second electrodes positioned in the third quadrant on the x-y plane with the electrostatic capacitance element comprised of the movable electrode and the first of the four first electrodes positioned in the first quadrant on the x-y plane, and connects in parallel one of the electrostatic capacitance elements comprised of the movable electrode and a third of the four second electrodes positioned in the first quadrant on the x-y plane and one of the electrostatic capacitance elements comprised of the movable electrode and a fourth of the four second electrodes positioned in the second quadrant on the x-y plane with the electrostatic capacitance element comprised of the movable electrode and the fourth of the first electrodes positioned in the third quadrant on the x-y plane; and
wherein the circuit of the second detection circuit connects in parallel the electrostatic capacitance element comprised of the movable electrode and the third of the four second electrodes positioned in the first quadrant on the x-y plane and the electrostatic capacitance element comprised of the movable electrode and the first of the four second electrodes positioned in the fourth quadrant on the x-y plane with the electrostatic capacitance element comprised of the movable electrode and the fourth of the four first electrodes positioned in the third quadrant on the x-y plane, and connects in parallel the electrostatic capacitance element comprised of the movable electrode and the second of the four second electrodes positioned in the third quadrant on the x-y plane and the electrostatic capacitance element comprised of the movable electrode and the fourth of the four second electrodes positioned in the second quadrant on the x-y plane with the electrostatic capacitance element comprised of the movable electrode and the first of the four first electrodes positioned in the first quadrant on the x-y plane.
- wherein the fixed electrodes further include four second electrodes on a plane which face the four first electrodes in an opposed manner by way of the mass;
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18. A dynamic amount sensor according to 16;
- wherein the fixed electrodes comprise a third electrode on a plane which face the first four electrodes in an opposed manner by way of the mass; and
wherein the third detecting circuit includes a circuit formed by connecting in series the electrostatic capacitance element comprised of the movable electrode and one of the four first electrodes and the electrostatic capacitance element comprised of the movable electrode and the third electrode.
- wherein the fixed electrodes comprise a third electrode on a plane which face the first four electrodes in an opposed manner by way of the mass; and
Specification