Method and circuit for driving touch sensors and display device using the same

• US 10,198,124 B2
• Filed: 12/28/2016
• Issued: 02/05/2019
• Est. Priority Date: 10/20/2015
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Display Co., Ltd.
• Inventors: Lee, Dukhyo, Jun, Jaehun, Kang, Hyeongwon, Kim, Beomjin
• Primary Examiner(s): Lee, Laurence J
• Application Number:
  US15/393,166
• Publication Number:
  US 20170108993A1
• Time in Patent Office: 769 Days
• 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 at least a first touch sensor and a second touch sensor; and

touch driving circuitry to;

supply one or more touch sensor driving signals to the first touch sensor and the second touch sensor during a touch sensing period; and

supply a reference voltage different from the touch sensor driving signals to the first touch sensor and the second touch sensor to measure a first electrical noise from the first touch sensor and the second touch sensor during a noise measurement period,

wherein the display panel is driven in a display period for image display and a touch period for touch sensing,

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 noise measurement period is a portion of the touch period.

2. The touch sensitive display device of claim 1, wherein the reference voltage is simultaneously supplied to the first touch sensor and the second touch sensor during the noise measurement period.

3. The touch sensitive display device of claim 1, wherein the first touch sensor and the second touch sensor are selectively shorted together during the noise measurement period to measure the first electrical noise from the first touch sensor and the second touch sensor.

4. The touch sensitive display device of claim 1, wherein the touch driving circuitry is to:

supply the reference voltage to the first touch sensor and the second touch sensor to measure a second electrical noise from the first touch sensor and the second touch sensor during another noise measurement period;

compare the first electrical noise to the second electrical noise; and

adjust an operating frequency of the touch driving circuitry based on the comparison of the first electrical noise to the second electrical noise.

5. The touch sensitive display device of claim 4, 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.

6. The touch sensitive display device of claim 4, wherein the operating frequency of the touch driving circuitry is a frequency at which one or more switches in the touch driving circuitry are turned on and off.

7. The touch sensitive display device of claim 1, wherein the reference voltage is a specific DC reference voltage.

8. A driver circuit for a display panel that comprises at least a first touch sensor and a second touch sensor, the driver circuit comprising:

touch driving circuitry to;

supply one or more touch sensor driving signals to the first touch sensor and the second touch sensor during a touch sensing period; and

supply a reference voltage different from the touch sensor driving signals to the first touch sensor and the second touch sensor to measure a first electrical noise from the first touch sensor and the second touch sensor during a noise measurement period,

wherein the display panel is driven in a display period for image display and a touch period for touch sensing,

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 noise measurement period is a portion of the touch period.

9. The driver circuit of claim 8, wherein the reference voltage is simultaneously supplied to the first touch sensor and the second touch sensor during the noise measurement period.

10. The driver circuit of claim 8, wherein the first touch sensor and the second touch sensor are selectively shorted together during the noise measurement period to measure the first electrical noise from the first touch sensor and the second touch sensor.

11. The driver circuit of claim 8, wherein the touch driving circuitry is to:

supply the reference voltage to the first touch sensor and the second touch sensor to measure a second electrical noise from the first touch sensor and the second touch sensor during another noise measurement period;

compare the first electrical noise to the second electrical noise; and

adjust an operating frequency of the touch driving circuitry based on the comparison of the first electrical noise to the second electrical noise.

12. The driver circuit of claim 11, 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.

13. The driver circuit of claim 11, wherein the operating frequency of the touch driving circuitry is a frequency at which one or more switches in the touch driving circuitry are turned on and off.

14. The driver circuit of claim 8, wherein the reference voltage is a specific DC reference voltage.

15. A method of operating a display device having a display panel being driven in a display period for image display and a touch period for touch sensing, the method comprising:

supplying one or more touch sensor driving signals to a first touch sensor and a second touch sensor of the display panel during a touch sensing portion of the touch period; and

supplying a reference voltage different from the touch sensor driving signals to the first touch sensor and the second touch sensor to measure a first electrical noise from the first touch sensor and the second touch sensor during a noise measurement period,

wherein the noise measurement period is a portion of the touch period.

16. The method of claim 15, wherein the reference voltage is simultaneously supplied to the first touch sensor and the second touch sensor during the noise measurement period.

17. The method of claim 15, further comprising:

selectively shorting together the first touch sensor and the second touch sensor during the noise measurement period to measure the first electrical noise from the first touch sensor and the second touch sensor.

18. The method of claim 15, further comprising:

supplying the reference voltage to the first touch sensor and the second touch sensor to measure a second electrical noise from the first touch sensor and the second touch sensor during another noise measurement period;

comparing the first electrical noise to the second electrical noise; and

adjusting an operating frequency of touch driving circuitry that supplies the reference voltage and the one or more touch driving signals, the operating frequency adjusted based on the comparison of the first electrical noise to the second electrical noise.

19. The method of claim 18, wherein the first electrical noise is measured while the touch driving circuitry is operating at a first frequency, and the second electrical noise is measured while the touch driving circuitry is operating at a second frequency different than the first frequency.

20. The method of claim 18, wherein the operating frequency of the touch driving circuitry is a frequency at which one or more switches in the touch driving circuitry are turned on and off.

21. The method of claim 15, wherein the reference voltage is a specific DC reference voltage.