Touch sensing device and method for driving the same
A touch sensing device includes a touch screen coupled with a display panel including data lines, gate lines crossing the data lines, and pixels arranged in a matrix form, and a touch sensing circuit which supplies a driving signal to lines of the touch screen and senses a touch input. The touch sensing circuit detects an optimum sensing time, in which changes in a voltage change of the gate lines are maintained within a previously determined allowable range, in a touch screen drive period in which data is not written to the pixels of the display panel. The touch sensing circuit supplies the driving signal to the lines of the touch screen only in the optimum sensing time of the touch screen drive period.
1. A touch sensing display device comprising:
a touch screen integrated with a display panel including data lines, gate lines crossing the data lines, touch electrodes for sensing a touch input, and pixels arranged in a matrix form at crossings of the gate lines and the data lines, the gate lines separate and disconnected from the touch electrodes; and
a touch sensing circuit configured to operate in a display mode or a touch mode according to a control signal, the control signal including a first period in which the control signal is at a first level indicative of the display mode and a second period in which the control signal is at second level indicative of the touch mode, wherein:
a common voltage is supplied to all the touch electrodes to display an image on the pixels during the first period of the control signal in which the control signal is at the first level;
the touch sensing circuit does not supply a touch driving signal to any of the touch electrodes during a first part of the second period of the control signal, the first part of the second period of the control signal immediately following the first period of the control signal and a ripple of voltage on the gate lines being outside a predetermined range in the first part of the second period of the control signal; and
the touch sensing circuit supplies the touch driving signal to one or more of the touch electrodes during a second part of the second period of the control signal, the second part of the second period of the control signal being subsequent to the first part of the second period of the control signal and the ripple of the voltage on the gate lines being within the predetermined range in the second part of the second period of the control signal, touch sensing signals from the one or more touch electrodes responsive to the touch drive signal being used to detect the touch input.
2. The touch sensing display device of claim 1 , further comprising a controller configured to time-divide one frame period into a display panel during the first period of the control signal and to not write data to the pixels of the display panel during the second period of the control signal.
3. The touch sensing display device of claim 2 , wherein the touch sensing circuit does not supply the touch driving signal to any of the touch electrodes during a third part of the second period of the control signal, the third part of the second of the control signal being subsequent to the second part of the second period of the control signal and immediately preceding another first period of the control signal of a subsequent frame, and the ripple of the voltage on the gate lines being outside the predetermined range in the third part of the second period of the control signal.
4. The touch sensing display device of claim 3 , wherein the ripple of a voltage measured at the gate lines during the second part of the second period of the control signal is less than a ripple of a voltage measured at the gate lines during the first part and the third part of the second period of the control signal.
5. The touch sensing display device of claim 3 , wherein the voltage at the gate lines is lowered from a first level to a second level during the first part of the second period of the control signal.
6. The touch sensing display device of claim 5 , wherein the voltage at the gate lines is increased from the second level to the first level during the third part of the second period of the control signal.
7. A method for driving a touch sensing display device including a touch screen integrated with a display panel including data lines, gate lines crossing the data lines, touch electrodes for sensing a touch input, and pixels arranged in a matrix form at crossing of the gate lines and the data lines, the gate lines separate and disconnected from the touch electrodes, the touch sensing display device operated in a display mode or a touch mode according to a control signal, the control signal including a first period in which the control signal is at a first level indicative of the touch mode, the method comprising:
supplying a common voltage to all the touch electrodes to display an image on the pixels during the first period of the control signal in which the control signal is at the first level;
not supplying a touch driving signal to any of the touch electrodes during a first part of the second period of the control signal, the first part of the second period of the control signal immediately following the first period of the control signal and a ripple of voltage on the gate lines being outside a predetermined range in the first part of the second period of the control signal; and
supplying the touch driving signal to one or more of the touch electrodes during a second part of the second period of the control signal, the second part of the second period of the control signal being subsequent to the first part of the second period of the control signal and the ripple of the voltage on the gate lines being within the predetermined range in the second part of the second period of the control signal, touch sensing signals from the one or more touch electrodes responsive to the touch drive signal being used to detect the touch input.
8. The method of claim 7 , further comprising:
not supplying the touch driving signal to any of the touch electrodes during a third part of the second period of the control signal, the third part of the second period of the control signal being subsequent to the second part of the second period of the control signal and immediately preceding another first period of the control signal of a subsequent frame, and the ripple of the voltage on the gate lines being outside the predetermined range in the third part of the second period of the control signal.
9. The method of claim 8 , wherein a ripple of a voltage measured in the gate lines during the second part of the second period of the control signal is less than a ripple of a voltage measured in the gate lines during the first part and the third part of the second period of the control signal.
10. The method of claim 7 ,
wherein data is written, to the pixels of the display panel during the first period of the control signal, and
wherein data is not written to the pixels of the display panel during the second period of the control signal.
11. The method of claim 8 , wherein the voltage at the gate lines is lowered from a first level to a second level during the first part of the second period of the control signal.
12. The method of claim 11 , wherein the voltage at the gate lines is increased from the second level to the first level during the third part of the second period of the control signal.
13. A driver circuit for driving a touch sensing display device including a touch screen integrated with a display panel including data lines, gate lines crossing the data lines, touch electrodes for sensing a touch input, and pixels arranged in a matrix form at crossings of the gate lines and the data lines, the gate lines separate and disconnected from the touch electrodes, the touch sensing display device operated in a display mode or a touch mode according to a control signal, the control signal including a first period in which the control signal is at a first level indicative of the display mode and a second period in which the control signal is at a second level indicative of the touch mode,
the driver circuit comprising circuitry to supply a common voltage or a touch driving signal, wherein:
the circuitry supplies the common voltage to all the touch electrodes to display an image on the pixels during the first period of the control signal in which the control signal is at the first level;
the circuitry does not supply the touch driving signal to any of the touch electrodes during a first part of the second period of the control signal, the first part of the second period of the control signal immediately following the first period of the control signal and a ripple of voltage on the gate lines being outside a predetermined range in the first part of the second period of the control signal; and
the circuitry supplies the touch driving signal to one or more of the touch electrodes during a second part of the second period of the control signal, the second part of the second period of the control signal being subsequent to the first part of the second period of the control signal and the ripple of the voltage on the gate lines being within the predetermined range in the second part of the second period of the control signal, touch sensing signals from the one or more touch electrodes responsive to the touch drive signal being used to detect the touch input.
14. The driver circuit of claim 13 ,
wherein the circuitry does not supply the touch driving signal to any of the touch electrodes during a third part of the second period of the control signal, the third part of the second period of the control signal being subsequent to the second part of the second period of the control signal and immediately preceding another first period of the control signal of a subsequent frame, and the ripple of the voltage on the gate lines being outside the predetermined range in the third part of the second period of the control signal.
15. The driver circuit of claim 14 , wherein the ripple of the voltage measured at the gate lines during the second part of the second period of the control signal is less than the ripple of the voltage measured at the gate lines during the first part and the third part of the second period of the control signal.
16. The driver circuit of claim 13 ,
wherein data is written to the pixels of the display panel during the first period of the control signal, and
wherein data is not written to the pixels of the display panel during the second period of the control signal.
17. The driver circuit of claim 14 , wherein the voltage at the gate lines is lowered from a first level to a second level during the first part of the second period of the control signal.
18. The driver circuit of claim 17 , wherein the voltage at the gate lines is increased from the second level to the first level during the third part of the second period of the control signal.