Method and circuit for driving touch sensors to reduce noise measurement time and display device using the same

Patent metadata

Field	Value
Publication number	US-9569035-B1
Application number	US-201514981313-A
Country	US
Kind code	B1
Filing date	Dec 28, 2015
Priority date	Oct 20, 2015
Publication date	Feb 14, 2017
Grant date	Feb 14, 2017

Abstract

Disclosed herein are a method and circuit for driving touch sensors and a display device using the same. A method of driving touch sensors includes supplying a touch sensor driving signal to the touch sensors or an amplifier and sensing a touch input during a touch input sensing portion and measuring current noise received through the touch sensors without the touch sensor driving signal during a noise measurement portion.

First claim

What is claimed is:

1. A touch sensitive display device comprising:
a display panel comprising a plurality of touch sensors; and
touch driving circuitry to:
supply one or more touch sensor driving signals to the plurality of touch sensors and to sense touch; and
measure first electrical noise of the plurality of touch sensors while the one or more touch sensor driving signals are not supplied to the plurality of touch sensors,
the touch driving circuitry comprising a circuit to selectively short together two or more of the plurality of touch sensors while the first electrical noise of the touch sensors is measured.

2. The touch sensitive display device of claim 1 ,
wherein the display panel is driven in a display period for image display and a touch period for touch sensing, and
wherein the touch driving circuitry supplies the one or more touch sensor driving signals and senses touch during a touch sensing portion of the touch period, and
wherein the touch driving circuitry measures the first electrical noise during a noise measurement portion of the touch period.

3. The touch sensitive display device of claim 1 , wherein the touch driving circuitry is to:
measure second electrical noise of the plurality of touch sensors while the one or more touch sensor driving signals are not supplied to the plurality of touch sensors;
compare the first electrical noise to the second electrical noise; and
adjust an operating frequency of the touch driving circuitry based on the comparison.

4. The touch sensitive display device of claim 3 , wherein the first electrical noise is measured by the touch driving circuitry while the touch driving circuitry is operating at a first frequency, and the second electrical noise is measured by the touch driving circuitry while the touch driving circuitry is operating at a second frequency different than the first frequency.

5. The touch sensitive display device of claim 1 , wherein the touch driving circuitry further comprises:
an amplifier to amplify a signal on one or more sensor lines connected to the one or more touch sensors of the plurality of touch sensors; and
an integrator to integrate an output signal of the amplifier,
wherein the touch driving circuitry senses touch and measures noise based on an output of the integrator.

6. The touch sensitive display device of claim 1 , further comprising:
a first touch sensing line;
a second touch sensing line;
a differential amplifier having a first amplifier input and a second amplifier input, the first amplifier input coupled to the first touch sensing line; and
a switching circuit to couple the second amplifier input to the second touch sensing line when touch is sensed, and to couple the second amplifier input to a reference voltage when noise is measured.

7. A driver circuit for a display panel that comprises a plurality of touch sensors, the driver circuit comprising:
circuitry to:
supply one or more touch sensor driving signals to the a plurality of touch sensors and to sense touch corresponding to the touch sensors; and
measure first electrical noise of the plurality of touch sensors while the one or more touch sensor driving signals are not supplied to the plurality of touch sensors,
the circuitry comprising a circuit to selectively short together two or more of the plurality of touch sensors while the first electrical noise of the touch sensors is measured.

8. The driver circuit of claim 7 ,
wherein the display panel is driven in a display period for image display and a touch period for touch sensing, and
wherein the circuitry supplies the one or more touch sensor driving signals and senses touch during a touch sensing portion of the touch period, and
wherein the circuitry measures the first electrical noise during a noise measurement portion of the touch period.

9. The driver circuit of claim 7 , wherein the circuitry is to:
measure second electrical noise of the plurality of touch sensors while the one or more touch sensor driving signals are not supplied to the plurality of touch sensors;
compare the first electrical noise to the second electrical noise; and
adjust an operating frequency of the touch driving circuitry based on the comparison.

10. The driver circuit of claim 9 , wherein the first electrical noise is measured by the circuitry while the circuitry is operating at a first frequency, and the second electrical noise is measured by the circuitry while the circuitry is operating at a second frequency different than the first frequency.

11. The driver circuit of claim 7 , wherein the circuitry further comprises:
an amplifier to amplify a signal on one or more sensor lines connected to one or more touch sensors of the plurality of touch sensors; and
an integrator to integrate an output signal of the amplifier,
wherein the circuitry senses touch and measures noise based on an output of the integrator.

12. The driver circuit of claim 7 , further comprising:
a differential amplifier having a first amplifier input and a second amplifier input, the first amplifier input coupled to a first touch sensing line; and
a switching circuit to couple the second amplifier input to a second touch sensing line when touch is sensed, and to couple the second amplifier input to a reference voltage when noise is measured.

13. A method of operating a display device having a display panel including a plurality of touch sensors, the method comprising:
supplying one or more touch sensor driving signals to the plurality of touch sensors and sensing touch corresponding to the touch sensors;
measuring first electrical noise of the plurality of touch sensors while the one or more touch sensor driving signals are not supplied to the plurality of touch sensors; and
selectively shorting together two or more of the plurality of touch sensors while the first electrical noise of the touch sensors is measured.

14. The method of claim 13 ,
wherein the display panel is driven in a display period for image display and a touch period for touch sensing, and
wherein the one or more touch sensor driving signals are supplied during a touch sensing portion of the touch period, and the touch is sensed during the touch sensing portion of the touch period; and
wherein the first electrical noise is measured during a noise measurement portion of the touch period.

15. The method of claim 13 , further comprising:
measuring second electrical noise of the plurality of touch sensors while the one or more touch sensor driving signals are not supplied to the plurality of touch sensors;
comparing the first electrical noise to the second electrical noise; and
adjusting an operating frequency of a touch driving circuitry based on the comparison.

16. The method of claim 15 , wherein the first electrical noise is measured by touch driving circuitry while the touch driving circuitry is operating at a first frequency, and the second electrical noise is measured by the touch driving circuitry while the touch driving circuitry is operating at a second frequency different than the first frequency.

17. The method of claim 13 , wherein the display device comprises a first touch sensing line, a second touch sensing line, and a differential amplifier having a first amplifier input and a second amplifier input, the first amplifier input coupled to the first touch sensing line, and the method further comprises:
switchably coupling the second amplifier input to the second touch sensing line when touch is sensed, and
switchably coupling the second amplifier input to a reference voltage when

Assignees

• Lg Display Co Ltd

Inventors

• Lee Dukhyo
• Jun Jaehun
• Kang Hyeongwon
• Kim Beomjin

Classifications

• G06F3/0418 Primary

  for error correction or compensation, e.g. based on parallax, calibration or alignment · CPC title

• G06F3/044 Primary

  by capacitive means · CPC title

• G06F3/0443 Primary

  using a single layer of sensing electrodes · CPC title

• G06F3/04166

  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 title

• G06F3/04184

  Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally · CPC title