Physical quantity sensor
First Claim
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1. A physical quantity sensor, comprising:
- a container;
a sensing element installed in the container for detecting a physical quantity; and
a viscous fluid that provides a damping when an external acceleration different from the physical quantity is applied to the sensor element;
wherein;
the sensing element is supported by the viscous fluid;
a viscosity of the viscous fluid is controllable by applying a voltage having an electric field and a magnetic field associated therewith, the voltage proportional to a magnitude of the external acceleration, the voltage changing the viscosity such that when the external acceleration is increased, the viscosity is increased proportionally thereby increasing an effective stiffness of the sensing element;
the sensing element includes a rectangular silicon-on-insulator (SOI) substrate having a beam structure, the beam structure including an oscillating body for detecting angular velocity, driving electrodes and detecting electrodes; and
the driving electrodes are provided with driving comb teeth and the detecting electrodes are provided with detecting comb shaped teeth.
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Abstract
The angular velocity sensor includes a container, a sensing element in the container and a viscous fluid between the container and the sensing element. The sensing element is supported by the viscous fluid such as an ER fluid or an MR fluid. The angular velocity sensor detects acceleration of the body in which the angular velocity sensor is installed. The angular velocity sensor controls the viscosity of the viscous fluid depending on the acceleration of a body, by changing a voltage applied to the viscous fluid.
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Citations
19 Claims
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1. A physical quantity sensor, comprising:
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a container; a sensing element installed in the container for detecting a physical quantity; and a viscous fluid that provides a damping when an external acceleration different from the physical quantity is applied to the sensor element;
wherein;the sensing element is supported by the viscous fluid; a viscosity of the viscous fluid is controllable by applying a voltage having an electric field and a magnetic field associated therewith, the voltage proportional to a magnitude of the external acceleration, the voltage changing the viscosity such that when the external acceleration is increased, the viscosity is increased proportionally thereby increasing an effective stiffness of the sensing element; the sensing element includes a rectangular silicon-on-insulator (SOI) substrate having a beam structure, the beam structure including an oscillating body for detecting angular velocity, driving electrodes and detecting electrodes; and the driving electrodes are provided with driving comb teeth and the detecting electrodes are provided with detecting comb shaped teeth. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
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14. A physical quantity sensor, comprising:
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a container; a sensing element installed in the container for detecting a physical quantity; and a viscous fluid that provides a damping when an external acceleration different from the physical quantity is applied to the sensor element;
wherein;the sensing element is supported by the viscous fluid; a viscosity of the viscous fluid is controllable by applying a voltage having an electric field and a magnetic field associated therewith, the voltage proportional to a magnitude of the external acceleration, the voltage changing the viscosity such that when the external acceleration is increased, the viscosity is increased proportionally thereby increasing an effective stiffness of the sensing element; and the physical quantity sensor further comprises a holding body for absorbing the viscous fluid, wherein the sensing element is fixed to the container through the holding body; and the holding body includes a substance that becomes one of a gel and a semisolid by absorbing the viscous fluid.
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15. A physical quantity sensor, comprising;
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a container; a sensing element installed in the container for detecting a physical quantity; and a viscous fluid that provides a damping when an external acceleration different from the physical quantity is applied to the sensor element;
wherein;the sensing element is supported by the viscous fluid; a viscosity of the viscous fluid is controllable by applying a voltage having an electric field and a magnetic field associated therewith, the voltage proportional to a magnitude of the external acceleration, the voltage changing the viscosity such that when the external acceleration is increased, the viscosity is increased proportionally thereby increasing an effective stiffness of the sensing element; the sensing element includes a rectangular silicon-on-insulator (SOI) substrate having a beam structure, the beam structure including an oscillating body for detecting the physical quantity, driving electrodes and detecting electrodes; and the driving electrodes are provided with driving teeth that are comb shaped and the detecting electrodes are provided with detecting teeth that are comb shaped. - View Dependent Claims (16, 17, 18)
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19. A physical quantity sensor, comprising:
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a container; a sensing element installed in the container for detecting a physical quantity; and a viscous fluid that provides a damping when an external acceleration different from the physical quantity is applied to the sensor element;
wherein;the sensing element is supported by the viscous fluid; a viscosity of the viscous fluid is controllable by applying a voltage having an electric field and a magnetic field associated therewith, the voltage proportional to a magnitude of the external acceleration; the voltage changes the viscosity such that when the external acceleration is increased, the viscosity is increased proportionally thereby increasing an effective stiffness of the sensing element; the sensor further comprises; an acceleration detection unit for detecting a value of the external acceleration; control electrodes; and a control unit coupled to the control electrodes and the acceleration detecting unit, the control unit controlling the viscosity of the viscous fluid, wherein the control unit is configured to receive the value of the external acceleration detected by the acceleration detecting unit, determine a relationship between the external acceleration and a damping factor that is associated with the viscosity of the viscous fluid, and apply the voltage based on the external acceleration, between the control electrodes to thereby change the viscosity of the viscous fluid with a change in the value of the external acceleration associated; and the acceleration detection unit includes a capacitance-type acceleration detector having a movable electrode and a fixed electrode with comb shaped teeth.
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Specification