INPUT DEVICE
First Claim
1. An input device, comprising:
- a selection circuit that is connected to a plurality of electrodes provided on a capacitive touch panel and selectively connects the plurality of electrodes;
a calibration resistor connected to the selection circuit;
a constant current source for supplying constant current power to the plurality of electrodes and the calibration resistor;
an A/D converter connected to the selection circuit to measure capacitance of the plurality of electrodes and a measured value measured when the calibration resistor is connected; and
a control unit controlling the selection circuit to make the A/D converter measure the capacitance of one of the plurality of electrodes and the measured value measured when the calibration resistor is connected, and determining a contact coordinate of the touch object on a touch panel by calculating a ratio of the capacitance to the measured value.
1 Assignment
0 Petitions
Accused Products
Abstract
An input device includes a selection circuit that is connected to a plurality of electrodes provided on a capacitive touch panel and selectively connects the plurality of electrodes, a calibration resistor connected to the selection circuit, a constant current source for supplying constant current power to the plurality of electrodes and the calibration resistor, an A/D converter connected to the selection circuit to measure capacitance of the plurality of electrodes and a measured value measured when the calibration resistor is connected, and a control unit controlling the selection circuit to make the A/D converter measure the capacitance of one of the plurality of electrodes and the measured value measured when the calibration resistor is connected, and determining a contact coordinate of the touch object on a touch panel by calculating a ratio of the capacitance to the measured value.
10 Citations
6 Claims
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1. An input device, comprising:
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a selection circuit that is connected to a plurality of electrodes provided on a capacitive touch panel and selectively connects the plurality of electrodes; a calibration resistor connected to the selection circuit; a constant current source for supplying constant current power to the plurality of electrodes and the calibration resistor; an A/D converter connected to the selection circuit to measure capacitance of the plurality of electrodes and a measured value measured when the calibration resistor is connected; and a control unit controlling the selection circuit to make the A/D converter measure the capacitance of one of the plurality of electrodes and the measured value measured when the calibration resistor is connected, and determining a contact coordinate of the touch object on a touch panel by calculating a ratio of the capacitance to the measured value. - View Dependent Claims (2, 3, 4, 5, 6)
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Specification