Capacitance change detection circuit, touch panel and determination method
First Claim
1. A capacitance change detection circuit, comprising:
- at least one set of contact electrodes including a set of a first contact electrode supplied with a pulse signal from an input unit for the pulse signal via phase inversion means, and a second contact electrode supplied with the pulse signal from the input unit;
a combining connection point that combines a first single output pulse output from the first contact electrode and a second single output pulse, corresponding to the first single output pulse, output from second contact electrode, and outputs a combined output;
a single amplification means connected to the combining connection point for amplifying combined output from the combining connection point, the combining connection point being provided between the at least one set of contact electrodes and the single amplification means;
first detection means for receiving the amplified combined output from the single amplification means and detecting a signal showing a state of the first contact electrode, the first detection means receiving the pulse signal via the phase inversion means to cancel signal indicative of a state of the second contact electrode;
second detection means for receiving the combined output from the single amplification means and detecting a signal showing the state of the second contact electrode, the second detection means receiving the pulse signal from the input unit to cancel signal indicative of the state of the first contact electrode; and
output units connected to the first detection means and the second detection means, respectively.
2 Assignments
0 Petitions
Accused Products
Abstract
A detection circuit 1 includes: an input unit 2; two contact electrodes A and B which are connected to the input unit; phase inversion unit 3 connected to the contact electrode A; one amplification unit 41 arranged in each contact unit; and detection units 5A and 5B which detect as an electric change amount, an amplitude change of an input signal caused by a capacitance change in each of the contact electrodes A and B. The detection circuit 1 causes the two electrodes to input signals having phases shifted by a half period from each other by using the phase inversion unit 3. In the presence of contact, the amplitude of the input pulses is amplified by the one amplification unit 41. The respective detection units 5A and 5B detect signals of respective electrodes from the one amplified signal and output them to output units 6A and 6B, respectively.
4 Citations
11 Claims
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1. A capacitance change detection circuit, comprising:
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at least one set of contact electrodes including a set of a first contact electrode supplied with a pulse signal from an input unit for the pulse signal via phase inversion means, and a second contact electrode supplied with the pulse signal from the input unit; a combining connection point that combines a first single output pulse output from the first contact electrode and a second single output pulse, corresponding to the first single output pulse, output from second contact electrode, and outputs a combined output; a single amplification means connected to the combining connection point for amplifying combined output from the combining connection point, the combining connection point being provided between the at least one set of contact electrodes and the single amplification means; first detection means for receiving the amplified combined output from the single amplification means and detecting a signal showing a state of the first contact electrode, the first detection means receiving the pulse signal via the phase inversion means to cancel signal indicative of a state of the second contact electrode; second detection means for receiving the combined output from the single amplification means and detecting a signal showing the state of the second contact electrode, the second detection means receiving the pulse signal from the input unit to cancel signal indicative of the state of the first contact electrode; and output units connected to the first detection means and the second detection means, respectively. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A capacitance change detection circuit, comprising:
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at least one set of contact electrodes including a set of a first contact electrode supplied with a pulse signal from an input unit for the pulse signal via phase inversion means, and a second contact electrode supplied with the pulse signal from the input unit; one amplification means connected to the one set of contact electrodes; first detection means for detecting a signal showing a state of the first contact electrode; second detection means for detecting a signal showing a state of the second contact electrode; and output units connected to the first detection means and the second detection means, respectively, wherein each of the first and second detection means comprises a diode, a resistor, and a capacitor, the diode of the first detection means has a cathode side connected to a first connection point supplied with the pulse signal from the phase inversion means, and has an anode side connected to a second connection point provided between an output side of the amplification means and the resistor of the first detection means, the diode of the second detection means has a cathode side connected to a third connection point supplied with the pulse signal from the input unit, and has an anode side connected to a fourth connection point provided between the output side of the amplification means and the resistor of the second detection means, and the resistor and the capacitor of each of the detection means constitute a smoothing circuit.
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Specification