Electronic device having touch sensor and driving method thereof

• US 9,904,404 B2
• Filed: 10/05/2015
• Issued: 02/27/2018
• Est. Priority Date: 10/06/2014
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Display Co., Ltd.
• Inventors: Kang, Hyeongwon, Jun, Jaehun, Lee, Dukhyo, Kim, Beomjin
• Primary Examiner(s): Simpson, Lixi C
• Application Number:
  US14/875,502
• Publication Number:
  US 20160098141A1
• Time in Patent Office: 876 Days
• CPC Class Codes: G06F 1/3262 Power saving in digitizer or tablet
• CPC Class Codes: G06F 1/3265 Power saving in display device
• CPC Class Codes: G06F 2203/04112 Electrode mesh in capacitive digitiser: electrode for touch sensing is formed of a mesh of very fine, normally metallic, interconnected lines that are almost invisible to see. This provides a quite large but transparent electrode surface, without need for ITO or similar transparent conductive material
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/041661 using detection at multiple resolutions, e.g. coarse and fine scanning; using detection within a limited area, e.g. object tracking window
• CPC Class Codes: G06F 3/044 by capacitive means
• CPC Class Codes: G06F 3/0443 using a single layer of sensing electrodes
• CPC Class Codes: Y02D 10/00 Energy efficient computing, e.g. low power processors, power management or thermal management

Abstract

A display device that comprises a plurality of touch electrodes and a touchscreen driving circuit coupled to the plurality of touch electrodes. In a normal display mode of the display device, the touchscreen driving circuit senses touch via the plurality of touch electrodes using self capacitance touch sensing. In a sleep mode of the display device, the touchscreen driving circuit senses touch via the plurality of touch electrodes using mutual capacitance touch sensing.

Claims

1. A display device comprising:

a plurality of touch electrodes; and

a touchscreen driving circuit coupled to the plurality of touch electrodes, the touchscreen driving circuit having a plurality of switches,

wherein in a normal display mode of the display device, the touchscreen driving circuit senses touch via the plurality of touch electrodes using self capacitance touch sensing; and

wherein in a sleep mode of the display device, the touchscreen driving circuit short circuits together a first set of the touch electrodes through the switches and senses touch via the plurality of touch electrodes using mutual capacitance touch sensing by driving a first touch driving signal to the first set of the touch electrodes that are shorted circuited together through the switches.

2. The display device of claim 1, wherein the touchscreen driving circuit is to, in the sleep mode of the display device:

short the first set of the touch electrodes along a line into a first transmit channel;

short a second set of the touch electrodes along a line into a receive channel;

drive the first touch driving signal onto the first transmit channel; and

sense touch from a voltage of the receive channel, the voltage generated based on the touch driving signal on the first transmit channel and a mutual capacitance between the first transmit channel and the receive channel.

3. The display device of claim 2, wherein the first transmit channel is parallel to the receive channel.

4. The display device of claim 2, wherein the touchscreen driving circuit is to:

short a third set of the touch electrodes along a line into a second transmit channel;

drive a second touch driving signal onto the second transmit channel; and

wherein the voltage of the receive channel is further generated based on the second touch driving signal and a mutual capacitance between the second transmit channel and the receive channel.

5. The display device of claim 4, wherein the first touch driving signal and the second touch driving signal are complementary signals.

6. The display device of claim 1, wherein the touch electrodes used for mutual capacitive touch sensing during the sleep mode are the touch electrodes used for self capacitive touch sensing during the normal display mode.

7. A display device comprising:

a plurality of touch electrodes; and

a touchscreen driving circuit coupled to the plurality of touch electrodes, the touchscreen driving circuit having a plurality of switches to selectively short circuit together at least a first set of the touch electrodes;

wherein in a normal display mode of the display device, the touchscreen driving circuit senses touch via the plurality of touch electrodes using self capacitance touch sensing; and

wherein in a sleep mode of the display device, the touchscreen driving circuit short circuits the first set of the touch electrodes together through the switches and senses touch via the first set of short circuited touch electrodes by driving a first touch driving signal to the first set of the touch electrodes that are short circuited together through the switches.

8. The display device of claim 7, wherein the first set of the touch electrodes are shorted along a line into a first transmit channel, and the touchscreen driving circuit is to, in the sleep mode of operation:

short a second set of the touch electrodes along a line into a receive channel;

drive the first touch driving signal onto the first transmit channel; and

sense touch from a voltage of the receive channel, the voltage generated based on the touch driving signal on the first transmit channel and a mutual capacitance between the first transmit channel and the receive channel.

9. The display device of claim 8, wherein the first transmit channel is parallel to the receive channel.

10. The display device of claim 8, wherein the touchscreen driving circuit is to, in the sleep mode of operation:

short a third set of the touch electrodes along a line into a second transmit channel;

drive a second touch driving signal onto the second transmit channel; and

wherein the voltage of the receive channel is further generated based on the second touch driving signal and a mutual capacitance between the second transmit channel and the receive channel.

11. The display device of claim 7, wherein the first set of short circuited touch electrodes comprises all touch electrodes of the display device.

12. The display device of claim 7, wherein the first set of short circuited touch electrodes comprises two or more lines of the touch electrodes.

13. A method of operation in a display device that includes a plurality of touch electrodes, comprising:

in a normal display mode of the display device, sensing touch via the plurality of touch electrodes using self capacitance touch sensing; and

in a sleep mode of the display device, sensing touch via the plurality of touch electrodes using mutual capacitance touch sensing by shorting circuiting together a first set of the touch electrodes through a plurality of switches and driving a first touch driving signal to the first set of the touch electrodes that are shorted circuited together through the switches.

14. The method of claim 13, wherein sensing touch in the sleep mode comprises:

shorting the first set of the touch electrodes along a line into a first transmit channel;

shorting a second set of the touch electrodes along a line into a receive channel;

driving the first touch driving signal onto the first transmit channel; and

sensing touch from a voltage of the receive channel, the voltage generated based on the touch driving signal on the first transmit channel and a mutual capacitance between the first transmit channel and the receive channel.

15. The method of claim 14, wherein sensing touch in the sleep mode comprises:

shorting a third set of the touch electrodes along a line into a second transmit channel; and

driving a second touch driving signal onto the second transmit channel,

wherein the voltage of the receive channel is further generated based on the second touch driving signal and a mutual capacitance between the second transmit channel and the receive channel.

16. A method of operation in a display device that includes a plurality of touch electrodes and a plurality of switches to selectively short circuit together at least a first set of the touch electrodes, comprising:

in a normal display mode of the display device, sensing touch via the plurality of touch electrodes using self capacitance touch sensing; and

in a sleep mode of the display device, short circuiting the first set of the touch electrodes together through the switches and sensing touch via the first set of short circuited touch electrodes by driving a first touch driving signal to the first set of the touch electrodes that are short circuited together through the switches.

17. The method of claim 16, wherein the first set of the touch electrodes are shorted along a line into a first transmit channel, and further comprising, in the sleep mode of operation:

shorting a second set of the touch electrodes along a line into a receive channel;

driving the first touch driving signal onto the first transmit channel; and

sensing touch from a voltage of the receive channel, the voltage generated based on the touch driving signal on the first transmit channel and a mutual capacitance between the first transmit channel and the receive channel.

18. The method of claim 17, further comprising, in the sleep mode of operation:

shorting a third set of the touch electrodes along a line into a second transmit channel;

driving a second touch driving signal onto the second transmit channel; and

wherein the voltage of the receive channel is further generated based on the second touch driving signal and a mutual capacitance between the second transmit channel and the receive channel.

19. The method of claim 16, wherein the first set of short circuited touch electrodes comprises all touch electrodes of the display device.

20. The method of claim 16, wherein the first set of short circuited touch electrodes comprises two or more lines of the touch electrodes.

21. A display device comprising:

a plurality of touch electrodes including a first set of the touch electrodes and a second set of the touch electrodes;

a plurality of sensing lines including a first set of the sensing lines and a second set of the sensing lines; and

a touchscreen driving circuit coupled to the first set of the touch electrodes and the second set of the touch electrodes and the touchscreen driving circuit including a first multiplexer and a second multiplexer;

wherein the first set of the touch electrodes is coupled to the first set of the sensing lines respectively and the second set of the touch electrodes is coupled to the second set of the sensing lines respectively,

wherein the first multiplexer is capable of short-circuiting the first set of the touch electrodes together through the first set of the sensing lines in a sleep mode of the display device and the touchscreen driving circuit is capable of driving the first set of the touch electrodes through the first set of the sensing lines in the sleep mode of the display device,

wherein the second multiplexer is capable of short-circuiting the second set of the touch electrodes together through the second set of the sensing lines in the sleep mode of the display device and the touchscreen driving circuit is capable of sensing the second set of the touch electrodes through the second set of the sensing lines in the sleep mode of the display device.