Touch display device and method of driving the same

• US 10,061,429 B2
• Filed: 07/29/2016
• Issued: 08/28/2018
• Est. Priority Date: 07/31/2015
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Display Co., Ltd.
• Inventors: Cho, Sungyong, Hwang, JongHee
• Primary Examiner(s): Patel, Premal R
• Application Number:
  US15/224,129
• Publication Number:
  US 20170031506A1
• Time in Patent Office: 760 Days
• CPC Class Codes: G02F 1/13338 Input devices, e.g. touch panels
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• 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 3/04184 Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally
• CPC Class Codes: G06F 3/0443 using a single layer of sensing electrodes

Abstract

A touch display device can include a touch panel having a plurality of subpixels, arranged between a first substrate and a second substrate, and a plurality of touch sensors arranged in units of a certain number of subpixels; an elastic layer on the second substrate; a display driver for supplying image signals to the plurality of subpixels, respectively; and a touch driver for supplying a touch driving signal to the plurality of touch sensors and sensing a touch position and a touch pressure which is applied when a touch is input to the touch panel, based on a capacitance variation of each of the plurality of touch sensors.

Claims

1. A touch display device comprising:

a touch panel configured to display an image, the touch panel including a plurality of subpixels arranged between a first substrate and a second substrate, and a plurality of touch sensors arranged in units of a certain number of subpixels;

an elastic layer on the second substrate;

a display driver configured to supply image signals to the plurality of subpixels, respectively; and

a touch driver configured to supply a touch driving signal to the plurality of touch sensors, sense a touch position of a touch based on a capacitance variation of a first touch sensor among the plurality of touch sensors, supply the touch driving signal to the first touch sensor and a plurality of second touch sensors surrounding the first touch sensor among the plurality of touch sensors, and sense a touch pressure of the touch position based on capacitance variations of the first touch sensor and the plurality of second touch sensors.

2. The touch display device of claim 1, further comprising:

a plurality of switches electrically connected to the plurality of touch sensors,

wherein the plurality of switches are adjacent to each other in up, down, left, and right directions.

3. The touch display device of claim 2, wherein when the touch is sensed from the first touch sensor, the touch driver turns on a plurality of switches disposed between the first touch sensor and the plurality of second touch sensors to electrically connect the first touch sensor to the plurality of second touch sensors, and turns on switches disposed between adjacent second touch sensors among the plurality of second touch sensors to electrically connect the adjacent second touch sensors among the plurality of second touch sensors.

4. The touch display device of claim 3, wherein a thickness of the elastic layer is changed by a force of the touch pressure, and the touch pressure is sensed based on a variation of a capacitance caused by the change in thickness of the elastic layer.

5. The touch display device of claim 4, wherein the touch pressure is divided into two or more levels.

6. The touch display device of claim 1, wherein a permittivity of the elastic layer is a value among 1 to 3.

7. The touch display device of claim 6, wherein the touch pressure is divided into two to four levels.

8. The touch display device of claim 1, wherein the plurality of touch sensors form a common electrode supplied with a common voltage during a display period for displaying the image.

9. A method of driving a touch display device, the method comprising:

supplying a touch driving signal to a plurality of touch sensors arranged in a touch panel;

sensing a touch position, based on a capacitance variation of each of the plurality of touch sensors;

in response to sensing a touch from a first touch sensor among the plurality of touch sensors, electrically connecting the first touch sensor to a plurality of second touch sensors surrounding the first touch sensor;

supplying the touch driving signal to the first touch sensor and the plurality of second touch sensors surrounding the first touch sensor; and

sensing a touch pressure of the touch, based on capacitance variations of the first touch sensor and the plurality of second touch sensors.

10. The method of claim 9, further comprising:

determining a touch pressure level for the touch pressure among a plurality of touch pressure levels, wherein the plurality of touch pressure levels are divided into two or more levels; and

providing a user interface based on the touch pressure level, wherein the touch pressure levels correspond to various user interfaces.

11. The method of claim 9, further comprising:

supplying the touch driving signal to nine touch sensors including the first touch sensor; and

sensing the touch pressure when the touch is input to the touch panel based on capacitance variations of the nine touch sensors.

12. The method of claim 9, further comprising:

supplying the touch driving signal to twenty-five touch sensors including the first touch sensor; and

sensing the touch pressure when the touch is input to the touch panel based on capacitance variations of the twenty-five touch sensors.

13. A touch display device comprising:

a touch panel configured to display an image, the touch panel including a plurality of subpixels arranged between a first substrate and a second substrate, and a plurality of touch sensors arranged in units of a certain number of subpixels;

an elastic layer on the second substrate;

a plurality of switches electrically connected to the plurality of touch sensors; and

a controller configured to;

divide a frame period into a display period for displaying the image and a touch period for touch sensing,

sense a touch input to the touch panel during the touch period by at least one touch sensor among the plurality of touch sensors,

turn on a set of switches among the plurality of switches and electrically connect the at least one touch sensor to a plurality of touch sensors surrounding the at least one touch sensor, in response to sensing the touch input by the at least one touch sensor,

supply a touch driving signal to the at least one touch sensor and the plurality of touch sensors surrounding the at least one touch sensor, and

sense a touch position and a touch pressure of the touch input based on the touch driving signal,

wherein the touch pressure is based on a capacitance variation of the at least one touch sensor and the plurality of touch sensors surrounding the at least one touch sensor, and

wherein the plurality of touch sensors form a common electrode supplied with a common voltage during the display period for displaying the image.

14. The touch display device of claim 13, wherein the plurality of switches are adjacent to each other in up, down, left, and right directions.

15. The touch display device of claim 13, wherein a thickness of the elastic layer is changed by a force of the touch pressure, and the touch pressure is sensed based on a variation of a capacitance caused by the change in thickness of the elastic layer.

16. The touch display device of claim 13, wherein the controller is further configured to:

determine a touch pressure level for the touch pressure among a plurality of touch pressure levels,

wherein the plurality of touch pressure levels are divided into two or more levels, and the two or more levels correspond to predetermined capacitance variations.

17. The touch display device of claim 16, wherein the touch pressure level is determined based on matching the touch pressure to one of the plurality of pressure levels in a look-up table.

18. The touch display device of claim 13, wherein the plurality of touch sensors surrounding the at least one touch sensor include nine to twenty-five touch sensors.