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

• US 9,569,035 B1
• Filed: 12/28/2015
• Issued: 02/14/2017
• Est. Priority Date: 10/20/2015
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Display Co., Ltd.
• Inventors: Jun, Jaehun, Lee, Dukhyo, Kang, Hyeongwon, Kim, Beomjin
• Primary Examiner(s): Sternbane, Larry
• Application Number:
  US14/981,313
• Time in Patent Office: 414 Days
• US Class Current: 1/1
• 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 3/0418 for error correction or compensation, e.g. based on parallax, calibration or alignment
• CPC Class Codes: G06F 3/04182 Filtering of noise external to the device and not generated by digitiser components
• 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
• CPC Class Codes: G06F 3/0446 using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes

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.

Claims

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 noise is measured.