CAPACITIVE TOUCH PANEL AND DISPLAY DEVICE WITH TOUCH DETECTION FUNCTION
First Claim
1. A capacitive touch panel comprising:
- a plurality of drive electrodes each applied with a drive signal for touch detection;
a plurality of touch detection electrodes arranged to intersect the plurality of drive electrodes so that electrostatic capacitance is formed at each of intersections of the drive electrodes and the touch detection electrodes, to output a detection signal synchronized with the drive signal;
a first sampling circuit extracting a first series of sampling signal from the detection signal outputted from each of the touch detection electrodes, the first series of sampling signal including a signal component with first level and a noise component;
a second sampling circuit extracting a second series of sampling signal from the detection signal outputted from each of the touch detection electrodes, the second series of sampling signal including a signal component with second level different from the first level and including a noise component;
a filter circuit performing a high range cut process which allows a band higher than or equal to a predetermined frequency to be cut from the first and second series of sampling signals outputted from the first and second sampling circuits, respectively; and
a computation circuit determining a signal for touch detection based on an output of the filter circuit.
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Accused Products
Abstract
A capacitive touch panel capable of reducing a disturbance noise and reducing touch detection time with a simple structure is obtained. The capacitive touch panel includes: a plurality of drive electrodes each to which a drive signal for touch detection is applied; a plurality of touch detection electrodes arranged to intersect the plurality of drive electrodes, and each outputting a detection signal synchronized with the drive signal; a first sampling circuit (A/D conversion circuits 72 and 73) extracting a first series of sampling signal including a signal component with first level and a noise component, from the detection signal; a second sampling circuit (A/D conversion circuits 75 and 76) extracting a second series of sampling signal including a signal component with second level different from the first level and the noise component, from the detection signal; a filter circuit (digital LPFs 81 and 82) performing a high range cut process on the first series of sampling signal and the second series of sampling signal; and a computation circuit (a subtraction circuit 90) determining a signal for touch detection based on an output of the filter circuit.
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Citations
15 Claims
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1. A capacitive touch panel comprising:
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a plurality of drive electrodes each applied with a drive signal for touch detection; a plurality of touch detection electrodes arranged to intersect the plurality of drive electrodes so that electrostatic capacitance is formed at each of intersections of the drive electrodes and the touch detection electrodes, to output a detection signal synchronized with the drive signal; a first sampling circuit extracting a first series of sampling signal from the detection signal outputted from each of the touch detection electrodes, the first series of sampling signal including a signal component with first level and a noise component; a second sampling circuit extracting a second series of sampling signal from the detection signal outputted from each of the touch detection electrodes, the second series of sampling signal including a signal component with second level different from the first level and including a noise component; a filter circuit performing a high range cut process which allows a band higher than or equal to a predetermined frequency to be cut from the first and second series of sampling signals outputted from the first and second sampling circuits, respectively; and a computation circuit determining a signal for touch detection based on an output of the filter circuit. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12)
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13. A display device with a touch detection function comprising:
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a plurality of drive electrodes each applied with a drive signal for touch detection; a plurality of touch detection electrodes arranged to intersect the plurality of drive electrodes so that electrostatic capacitance is formed at each of intersections of the drive electrodes and the touch detection electrodes, to output a detection signal synchronized with the drive signal; a first sampling circuit extracting a first series of sampling signal from the detection signal outputted from each of the touch detection electrodes, the first series of sampling signal including a signal component with first level and a noise component; a second sampling circuit extracting a second series of sampling signal from the detection signal outputted from each of the touch detection electrodes, the second series of sampling signal including a signal component with second level different from the first level and including a noise component; a filter circuit performing a high range cut process which allows a band higher than or equal to a predetermined frequency to be cut from the first and second series of sampling signals outputted from the first and second sampling circuits, respectively; and a computation circuit determining a signal for touch detection based on an output of the filter circuit; and a display section displaying an image based on an image signal. - View Dependent Claims (14, 15)
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Specification