Capacitive physical quality detection device
First Claim
1. A capacitive physical quality detection device comprising:
- a sensor part including;
a movable electrode configured to be displaced by changing of a physical quantity;
a first fixed electrode disposed to face a first portion of the movable electrode; and
a second fixed electrode disposed to face a second portion of the movable electrode;
a control circuit configured to apply a signal between the movable electrode and the first fixed electrode, and between the movable electrode and the second fixed electrode; and
a CV conversion circuit configured to receive a reference voltage and to output a voltage corresponding to a capacitance change between the movable electrode and the first fixed electrode, and between the movable electrode and the second fixed electrode,wherein;
in a first time period, the control circuit applies a first signal to the first fixed electrode and applies a second signal to the second fixed electrode, the second signal being opposite in phase to the first signal,in a second time period, the control circuit applies the reference voltage to the first fixed electrode and applies the second signal to the second fixed electrode, andan amplitude of the second signal in the first time period is the same as an amplitude of the second signal in the second time period.
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Accused Products
Abstract
A capacitive physical quality detection device includes a sensor part, a control circuit, and a CV conversion circuit. The sensor part includes a movable electrode, a first fixed electrode, and a second fixed electrode. The CV conversion circuit is configured to receive a reference voltage and to output a voltage corresponding to a capacitance change. In a first time period, the control circuit applies a first signal to the first fixed electrode, and applies a second signal, which is opposite in phase to the first signal, to the second fixed electrode. In a second time period, the control circuit applies the reference voltage to the first fixed electrode and applies the second signal to the second fixed electrode.
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Citations
11 Claims
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1. A capacitive physical quality detection device comprising:
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a sensor part including; a movable electrode configured to be displaced by changing of a physical quantity; a first fixed electrode disposed to face a first portion of the movable electrode; and a second fixed electrode disposed to face a second portion of the movable electrode; a control circuit configured to apply a signal between the movable electrode and the first fixed electrode, and between the movable electrode and the second fixed electrode; and a CV conversion circuit configured to receive a reference voltage and to output a voltage corresponding to a capacitance change between the movable electrode and the first fixed electrode, and between the movable electrode and the second fixed electrode, wherein; in a first time period, the control circuit applies a first signal to the first fixed electrode and applies a second signal to the second fixed electrode, the second signal being opposite in phase to the first signal, in a second time period, the control circuit applies the reference voltage to the first fixed electrode and applies the second signal to the second fixed electrode, and an amplitude of the second signal in the first time period is the same as an amplitude of the second signal in the second time period. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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Specification