Coordinate input device and display device including the same
First Claim
1. A coordinate input device comprising:
- a coordinate input unit having a plurality of first detection electrodes, which are disposed in parallel to each other, and a plurality of second detection electrodes intersecting the first detection electrodes;
an electrode drive circuit configured to apply a drive signal to one or more of the first detection electrodes;
a capacitance detection circuit configured to detect a capacitance of the second detection electrode in synchronization with the drive signal;
wherein the electrode drive circuit is configured to select one or more of the first detection electrodes to which the drive signal is not applied as a reference electrode;
wherein the capacitance detection circuit is configured to detect a capacitance of the selected reference electrode, which capacitance represents noise;
an input coordinate computing circuit configured to correct a capacitance detection result of the capacitance detection circuit on the basis of the detected capacitance representing noise of the reference electrode, and to calculate an input coordinate from the corrected capacitance detection result.
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Accused Products
Abstract
Provided is a coordinate input device including: a coordinate input unit having a plurality of first detection electrodes and a plurality of second detection electrodes; an electrode drive circuit that applies a drive signal to one or more of the detection electrodes; a capacitance detection circuit that detects a capacitance of the first and/or second detection electrode; means for selecting one or more of the detection electrodes to which the drive signal is not applied from among the detection electrodes which are disposed in parallel to the detection electrodes to which the drive signal is applied, as a reference electrode; means for detecting a capacitance of the selected reference electrode; means for correcting a capacitance detection result of the capacitance detection circuit on the basis of the detected capacitance of the reference electrode; and an input coordinate computing circuit that calculates an input coordinate from the corrected capacitance detection result.
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Citations
12 Claims
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1. A coordinate input device comprising:
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a coordinate input unit having a plurality of first detection electrodes, which are disposed in parallel to each other, and a plurality of second detection electrodes intersecting the first detection electrodes; an electrode drive circuit configured to apply a drive signal to one or more of the first detection electrodes; a capacitance detection circuit configured to detect a capacitance of the second detection electrode in synchronization with the drive signal; wherein the electrode drive circuit is configured to select one or more of the first detection electrodes to which the drive signal is not applied as a reference electrode; wherein the capacitance detection circuit is configured to detect a capacitance of the selected reference electrode, which capacitance represents noise; an input coordinate computing circuit configured to correct a capacitance detection result of the capacitance detection circuit on the basis of the detected capacitance representing noise of the reference electrode, and to calculate an input coordinate from the corrected capacitance detection result. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A display apparatus comprising:
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a display panel configured to display an image based on an image signal from an external system; and a coordinate input device disposed on a display surface side of the display panel, wherein the coordinate input device includes a coordinate input unit in which a plurality of first detection electrodes, which are disposed in parallel to each other, and a plurality of second detection electrodes intersecting the first detection electrodes are formed, and which is disposed on the display surface side of the display panel, an electrode drive circuit configured to apply a drive signal to one or more of the first detection electrodes, a capacitance detection circuit configured to detect a capacitance of the second detection electrode in synchronization with the drive signal, the electrode drive circuit configured to select one or more of the first detection electrodes to which the drive signal is not applied as a reference electrode, a circuit configured to detect a capacitance of the selected reference electrode, which capacitance represents noise, an input coordinate computing circuit configured to correct a capacitance detection result of the capacitance detection circuit on the basis of the detected capacitance representing noise of the reference electrode, and to calculate an input coordinate from the corrected capacitance detection result. - View Dependent Claims (8, 9, 10, 11, 12)
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Specification