Driving circuit, touch display device, and method of driving the touch display device

• US 10,120,490 B2
• Filed: 07/21/2016
• Issued: 11/06/2018
• Est. Priority Date: 01/29/2016
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Display Co., Ltd.
• Inventors: Kim, SungChul, Kim, JuHan
• Primary Examiner(s): Faragalla, Michael
• Assistant Examiner(s): Bibbee, Chayce
• Application Number:
  US15/216,656
• Publication Number:
  US 20170220183A1
• Time in Patent Office: 838 Days
• CPC Class Codes: G06F 2203/04103 Manufacturing, i.e. details related to manufacturing processes specially suited for touch sensitive devices
• CPC Class Codes: G06F 2203/04105 Pressure sensors for measuring the pressure or force exerted on the touch surface without providing the touch position
• CPC Class Codes: G06F 2203/04107 Shielding in digitiser, i.e. guard or shielding arrangements, mostly for capacitive touchscreens, e.g. driven shields, driven grounds
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/04164 Connections between sensors and controllers, e.g. routing lines between electrodes and connection pads
• CPC Class Codes: G06F 3/04166 Details of scanning methods, e.g. sampling time, grouping of sub areas or time sharing with display driving Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally G06F3/04184
• CPC Class Codes: G06F 3/0445 using two or more layers of sensing electrodes, e.g. using two layers of electrodes separated by a dielectric layer
• CPC Class Codes: G06F 3/0447 Position sensing using the local deformation of sensor cells

Abstract

A driving circuit, a touch display device, and a method of driving the touch display device, in which, when a user touches a screen, not only can a touch point be sensed, but also a level of touch force with which the user presses the screen can also be efficiently sensed, in order to provide a range of functions. It is possible to provide a variety of functions that are not supported by related-art touch sensing technologies.

Claims

1. A touch display device comprising:

a plurality of first electrodes disposed within a display panel;

one or more second electrodes disposed outside of the display panel and separated from the first electrodes by a gap; and

a driving circuit to;

provide a touch driving signal to at least one first electrode among the plurality of first electrodes in a touch driving period of a frame period, the touch driving signal provided to the at least one first electrode having a plurality of pulses during the touch driving period of the frame period;

during the touch driving period, sense a touch position based on a change in capacitance between the first electrode provided with the touch driving signal and a pointer;

provide a first force driving signal to the at least one first electrode among the plurality of first electrodes during a force driving period, and provide a second force driving signal different than the first force driving signal to the one or more second electrodes during the force driving period; and

during the force driving period, sense a touch force based on a change in capacitance between a group of the first electrodes provided with the first force driving signal and the one or more second electrodes provided with the second force driving signal,

wherein the group of the first electrodes includes at least two first electrodes and the at least two first electrodes are electrically connected to each other.

2. The touch display device of claim 1, wherein the driving circuit time divides the frame period into a display driving period, the touch driving period, and the force driving period, wherein the driving circuit provides a common voltage to the first electrodes during the display driving period.

3. The touch display device of claim 1, wherein, in the touch driving period, when the touch driving signal is provided to the at least one first electrode among the plurality of first electrodes, the driving circuit applies a load-free driving signal to the second electrode, the load-free driving signal being in-phase with the touch driving signal.

4. The touch display device of claim 1, wherein, in the force driving period,

the first force driving signal and the second force driving signal are pulse signals;

the first force driving signal is a signal having a first direct-current voltage, and the second force driving signal is a signal having a second direct-current voltage;

the first force driving signal is a pulse signal, and the second force driving signal is a signal having the second direct-current voltage;

or

the first force driving signal is a signal having the first direct-current voltage, and the second force driving signal is a pulse signal.

5. The touch display device of claim 4, wherein, in the force driving period, when the first force driving signal and the second force driving signal are pulse signals, the first force driving signal is in-phase with or in reverse phase with the second force driving signal.

6. The touch display device of claim 5, wherein, in the force driving period, when the first force driving signal and the second force driving signal are pulse signals, the second force driving signal is in-phase with the first force driving signal, and an amplitude of the second force driving signal is greater than an amplitude of the first force driving signal.

7. The touch display device of claim 4, wherein the first direct-current voltage is a first reference voltage or a ground voltage, the second direct-current voltage is a second reference voltage or a ground voltage, and the first reference voltage and the second reference voltage are the same voltage or are different voltages.

8. The touch display device of claim 4, wherein, in the force driving period, when the first force driving signal is a signal having a first direct-current voltage and the second force driving signal is a signal having a second direct-current voltage, the first direct-current voltage and the second direct-current voltage are different voltages.

9. The touch display device of claim 1, wherein a size of the gap is changeable depending on a level of touch force.

10. The touch display device of claim 1, wherein, in the force driving period, the driving circuit detects a level of touch force by determining a change in capacitance between each of the one or more first electrodes and the one or more second electrode based on a signal received from each of the first electrodes, the signal generated based on the first force driving signal and the second force driving signal.

11. The touch display device of claim 1, wherein, in the force driving period, the driving circuit detects a level of touch force by determining a change in capacitance between each of the one or more first electrodes and the one or more second electrodes based on a signal received from a group of the first electrodes that includes at least two first electrodes among the one or more first electrodes.

12. The touch display device of claim 1, wherein the one or more second electrodes comprise a plurality of second electrodes.

13. The touch display device of claim 12, wherein, in the force driving period, the driving circuit applies a second force driving signal to a specific second electrode among the plurality of second electrodes corresponding to the touch position detected in the touch driving period.

14. The touch display device of claim 13, wherein, in the force driving period, the driving circuit applies the first force driving signal to all of the plurality of first electrodes or applies the first force driving signal to a first electrode among the plurality of first electrodes corresponding to the specific second electrode when providing a second force driving signal to the specific second electrode.

15. The touch display device of claim 13, wherein, in the force driving period, the driving circuit applies a second force driving signal to the specific second electrode and surrounding second electrodes close to the specific second electrode, applies the first force driving signal to all of the plurality of first electrodes, or applies the first force driving signal to first electrodes among the plurality of first electrodes corresponding to the specific second electrode and the surrounding second electrodes.

16. The touch display device of claim 1, wherein the touch driving signal and the first force driving signal are a same signal.

29. The touch display device of claim 1, wherein one or more second electrodes are floated during the touch driving period while the touch driving signal is provided to the at least one first electrode among the plurality of first electrodes.

30. The touch display device of claim 1, wherein a capacitance corresponding to the gap between the plurality of first electrodes and the one or more second electrodes changes depending on presence of the force touch.

17. A method of driving a touch display device, the touch display device comprising a plurality of first electrodes disposed within a display panel and one or more second electrodes separated from the first electrodes by a gap, the method comprising:

providing a touch driving signal to at least one first electrode among the plurality of first electrodes disposed within the display panel during a touch driving period of a frame period, the touch driving signal provided to the at least one first electrode having a plurality of pulses during the touch driving period of the frame period;

during the touch driving period, sensing a touch position based on a change in capacitance between the first electrode provided with the touch driving signal and a pointer;

providing a first force driving signal to the at least one first electrode among the plurality of first electrodes disposed within the display panel during a force driving period, and providing a second force driving signal different than the first force driving signal to the one or more second electrodes disposed outside of the display panel during the force driving period; and

during the force driving period, sensing a touch force based on a change in capacitance between a group of the first electrodes provided with the first force driving signal and the one or more second electrodes provided with the second force driving signal,

wherein the group of the first electrodes includes at least two first electrodes and the at least two first electrodes are electrically connected to each other.

18. A driving circuit for driving touch display device, the touch display device comprising a plurality of first electrodes disposed within a display panel and one or more second electrodes separated from the first electrodes by a gap, the driving circuit comprising:

a first circuit to provide a touch driving signal to at least one first electrode among the plurality of first electrodes disposed within the display panel during a touch driving period of a frame period, the touch driving signal provided to the at least one first electrode having a plurality of pulses during the touch driving period of the frame period, the first circuit to provide a first force driving signal to the at least one first electrode among the plurality of first electrodes disposed within the display panel during a force driving period, and the first circuit to provide a second force driving signal different than the first force driving signal to the one or more second electrodes disposed outside of the display panel during the force driving period; and

a second circuit to sense a touch position based on a change in capacitance between the first electrode provided with the touch driving signal and a pointer and to sense a touch force based on a change in capacitance between a group of the first electrodes provided with the first force driving signal and the one or more second electrodes provided with the second force driving signal,

wherein the group of the first electrodes includes at least two first electrodes and the at least two first electrodes are electrically connected to each other.

19. The driving circuit of claim 18, wherein the driving circuit time divides the frame period into a display driving period, the touch driving period, and the force driving period, wherein the first circuit provides a common voltage to the first electrodes during the display driving period.

20. The driving circuit of claim 18, wherein, in the touch driving period, when the touch driving signal is provided to the at least one first electrode among the plurality of first electrodes, the first circuit applies a load-free driving signal to the second electrode, the load-free driving signal being in-phase with the touch driving signal.

21. The driving circuit of claim 18, wherein, in the force driving period,

the first force driving signal and the second force driving signal are pulse signals;

the first force driving signal is a signal having a first direct-current voltage, and the second force driving signal is a signal having a second direct-current voltage;

the first force driving signal is a pulse signal, and the second force driving signal is a signal having the second direct-current voltage;

or

the first force driving signal is a signal having the first direct-current voltage, and the second force driving signal is a pulse signal.

22. The driving circuit of claim 21, wherein, in the force driving period, when the first force driving signal and the second force driving signal are pulse signals, the first force driving signal is in-phase with or in reverse phase with the second force driving signal.

23. The driving circuit of claim 22, wherein, in the force driving period, when the first force driving signal and the second force driving signal are pulse signals, the second force driving signal is in-phase with the first force driving signal, and an amplitude of the second force driving signal is greater than an amplitude of the first force driving signal.

24. The driving circuit of claim 21, wherein the first direct-current voltage is a first reference voltage or a ground voltage, the second direct-current voltage is a second reference voltage or a ground voltage, and the first reference voltage and the second reference voltage are the same voltage or are different voltages.

25. The driving circuit of claim 21, wherein, in the force driving period, when the first force driving signal is a signal having a first direct-current voltage and the second force driving signal is a signal having a second direct-current voltage, the first direct-current voltage and the second direct-current voltage are different voltages.

26. The driving circuit of claim 18, wherein, in the force driving period, the second circuit detects a level of touch force by determining a change in capacitance between each of the one or more first electrodes and the one or more second electrode based on a signal received from each of the first electrodes, the signal generated based on the first force driving signal and the second force driving signal.

27. The driving circuit of claim 18, wherein, in the force driving period, the second circuit detects a level of touch force by determining a change in capacitance between each of the one or more first electrodes and the one or more second electrodes based on a signal received from a group of the first electrodes that includes at least two first electrodes among the one or more first electrodes.

28. The driving circuit of claim 18, wherein, the one or more second electrodes comprise a plurality of second electrodes, and in the force driving period, the first circuit applies a second force driving signal to a specific second electrode among the plurality of second electrodes corresponding to the touch position detected in the touch driving period.