Method of driving touch panel, capacitance-type touch panel, and display apparatus with touch detection function
First Claim
1. A capacitance-type touch panel display comprising:
- a plurality of drive electrodes;
a drive control circuit performing control such that a drive signal for touch detection is selectively applied to the drive electrodes;
a plurality of touch detection electrodes arranged to form capacitance with the drive electrodes, and each outputting a detection signal in synchronization with the drive signal; and
a detection circuit detecting an external proximity object based on the detection signal,wherein the drive control circuit controls application of the drive signal such that a positive drive signal is selectively applied to predetermined regions of the touch panel display in a first period;
a negative drive signal is applied to predetermined regions of the touch panel display in a second period different from the first period so that there is a difference in surface area of the drive electrodes receiving the positive and negative drive signals for contact detection thereby causing a time-average level of the detection signal both in the first period and the second period to be shifted with respect to a center voltage of the detection signal when a portion of the display is contacted or approached due to a difference in capacitance between the first period and the second period; and
the detection circuit detects the external proximity object based on a shift of the time-average level of the detection signal both in the first period and the second period with respect to the center voltage of the detection signal.
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Abstract
A capacitance-type touch panel, allowing disturbance noise and touch detection time to be reduced and having a simple configuration, is provided. The capacitance-type touch panel including: a plurality of drive electrodes each having a strip shape; a drive control circuit performing control such that a drive signal for touch detection is selectively applied to the drive electrodes; a plurality of touch detection electrodes arranged to intersect with the drive electrodes in such a manner that capacitance is formed in each intersecting part, and each outputting a detection signal in synchronization with the drive signal; and a detection circuit detecting an external proximity object based on the detection signal. The drive control circuit controls application of the drive signal in such a manner that the detection signal is a polarity-alternating signal including a positive-negative asymmetrical signal component which is due to presence of the external proximity object.
16 Citations
14 Claims
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1. A capacitance-type touch panel display comprising:
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a plurality of drive electrodes; a drive control circuit performing control such that a drive signal for touch detection is selectively applied to the drive electrodes; a plurality of touch detection electrodes arranged to form capacitance with the drive electrodes, and each outputting a detection signal in synchronization with the drive signal; and a detection circuit detecting an external proximity object based on the detection signal, wherein the drive control circuit controls application of the drive signal such that a positive drive signal is selectively applied to predetermined regions of the touch panel display in a first period; a negative drive signal is applied to predetermined regions of the touch panel display in a second period different from the first period so that there is a difference in surface area of the drive electrodes receiving the positive and negative drive signals for contact detection thereby causing a time-average level of the detection signal both in the first period and the second period to be shifted with respect to a center voltage of the detection signal when a portion of the display is contacted or approached due to a difference in capacitance between the first period and the second period; and the detection circuit detects the external proximity object based on a shift of the time-average level of the detection signal both in the first period and the second period with respect to the center voltage of the detection signal. - View Dependent Claims (2, 3, 4, 5, 6, 7)
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8. A display apparatus with a touch detection function comprising:
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a plurality of drive electrodes; a drive control circuit performing control such that a drive signal for touch detection is selectively applied to the drive electrodes; a plurality of touch detection electrodes arranged to form capacitance with the drive electrodes, and each outputting a detection signal in synchronization with the drive signal; a detection circuit detecting an external proximity object based on the detection signal; and a display section displaying an image based on an image signal, wherein the drive control circuit controls application of the drive signal such that a positive drive signal is selectively applied to predetermined regions of the display in a first period; a negative drive signal is applied to predetermined regions of the display in a second period different from the first period so that there is a difference in surface area of the drive electrodes receiving the positive and negative drive signals for contact detection thereby causing a time-average level of the detection signal both in the first period and the second period to be shifted with respect to a center voltage of the detection signal when a portion of the display is contacted or approached due to a difference in capacitance between the first period and the second period; and the detection circuit detects the external proximity object based on a shift of the time-average level of the detection signal both in the first period and the second period with respect to the center voltage of the detection signal. - View Dependent Claims (9, 10, 11, 12, 13)
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14. A method of driving a touch panel display, comprising steps of:
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selectively applying a drive signal for touch detection to a plurality of drive electrodes; allowing each of a plurality of touch detection electrodes to output a detection signal in synchronization with the drive signal when an external proximity object exists, the touch detection electrodes being arranged form capacitance with the drive electrodes, and the detection signal being applied such that a positive drive signal is selectively applied to predetermined regions of the display in a first period and a negative drive signal is applied to predetermined regions of the display in a second period different from the first period so that there is a difference in surface area of the drive electrodes receiving the positive and negative drive signals for contact detection thereby causing a time-average level of the detection signal both in the first period and the second period to be shifted with respect to a center voltage of the detection signal when a portion of the display is contacted or approached due to a difference in capacitance between the first period and the second period; and detecting the external proximity object based a shift of the time-average level of the detection signal both in the first period and the second period with respect to the center voltage of the detection signal.
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Specification