Touch display device and touch driving circuit

Patent metadata

Field	Value
Publication number	US-11360620-B2
Application number	US-201916712015-A
Country	US
Kind code	B2
Filing date	Dec 12, 2019
Priority date	Dec 27, 2018
Publication date	Jun 14, 2022
Grant date	Jun 14, 2022

Abstract

A touch display device includes: a touch panel including N touch electrodes; a sensor sensing unit block including M sensor sensing units and to sense two or more touch electrodes among the N touch electrodes; a front multiplexer to select two or more touch electrodes from among the N touch electrodes and connect the selected touch electrodes to the sensor sensing unit block. The front multiplexer is configured to select M touch electrodes, which are disposed in a sensing active region corresponding to a first sensing period, from among the N touch electrodes, and to match and connect the M touch electrodes to the M sensor sensing units, wherein M is greater than or equal to 2, and N is greater than M. The M sensor sensing units are configured to simultaneously sense the M touch electrodes disposed in the sensing active region during the first sensing period.

First claim

What is claimed is:

1. A touch display device, comprising:
a touch panel comprising N touch electrodes;
a sensor sensing unit block configured to sense two or more touch electrodes among the N touch electrodes; and
a front multiplexer configured to select the two or more touch electrodes among the N touch electrodes and connect the selected touch electrodes to the sensor sensing unit block,
wherein the sensor sensing unit block comprises M sensor sensing units, M is greater than or equal to 2, and N is greater than M,
wherein the front multiplexer is configured to select M touch electrodes, which are disposed in a sensing active region corresponding to a first sensing period, from among the N touch electrodes, and to match and connect the M touch electrodes to the M sensor sensing units,
wherein the M sensor sensing units are configured to simultaneously sense the M touch electrodes disposed in the sensing active region during the first sensing period, and
wherein the front multiplexer comprises:
a first-multiplexer configured to select the 2M touch electrodes from among the N touch electrodes, and to set a differential sensing region;
M second-multiplexers corresponding to the M sensor sensing units, and configured to group the 2M touch electrodes into M touch electrode pairs; and
M third-multiplexers corresponding to the M sensor sensing units, and configured to selectively connect two touch electrodes included in each of the M touch electrode pairs to a sensing input end and a reference input end of a differential amplifier included in each of the M sensor sensing units.

2. The touch display device of claim 1 , wherein each of the M sensor sensing units comprises a differential amplifier having a sensing input end and a reference input end,
the front multiplexer is configured to:
select the M touch electrodes disposed in the sensing active region from among the N touch electrodes, as M sensing electrodes;
further select other M touch electrodes from among N-M touch electrodes remaining after excluding the M touch electrodes from the N touch electrodes, as M reference electrodes;
connect each of the M sensing electrodes to a sensing input end of the differential amplifier of each of the M sensor sensing units; and
connect each of the M reference electrodes to a reference input end of the differential amplifier of each of the M sensor sensing units, and the differential amplifier of each of the M sensor sensing units differentially amplifies a first input signal and a second input signal, which are input from a corresponding sensing electrode and a corresponding reference electrode, respectively.

3. The touch display device of claim 2 , wherein the first-multiplexer is configured to: select the 2M touch electrodes from among the N touch electrodes, and to provide a load-free driving signal to touch electrodes remaining after excluding the 2M touch electrodes from the N touch electrodes.

4. The touch display device of claim 2 , wherein, when grouping the 2M touch electrodes into the M touch electrode pairs, the M second-multiplexers group two touch electrodes, disposed to be adjacent to each other, into a single touch electrode pair.

5. The touch display device of claim 2 , wherein, when grouping the 2M touch electrodes into the M touch electrode pairs, the M second-multiplexers group two touch electrodes, disposed to be spaced apart from each other, into a single touch electrode pair.

6. The touch display device of claim 2 , wherein each of the M second-multiplexers comprises:
a first switch and a second switch which group a first touch electrode and a second touch electrode adjacent to the first touch electrode, at a first sensing timing; and
a third switch and a fourth switch which group the second touch electrode and a third touch electrode adjacent to the second touch electrode, at a second sensing timing.

7. The touch display device of claim 2 , wherein each of the M second-multiplexers comprises a fifth switch and a sixth switch which group a first touch electrode and a second touch electrode which is spaced one or more touch electrodes apart from the first touch electrode.

8. The touch display device of claim 2 , wherein each of the M third-multiplexers comprises four polarity assignment switches which selectively connect two touch electrodes included in each of the M touch electrode pairs to a sensing input end and a reference input end of a differential amplifier of a corresponding sensor sensing unit.

9. The touch display device of claim 1 , wherein the touch panel comprises a plurality of touch electrode rows,
the sensing active region comprises H touch electrode rows from among the plurality of touch electrode rows, and
the front multiplexer changes a first touch electrode row of the sensing active region in units of rows.

10. The touch display device of claim 9 , wherein the front multiplexer comprises:
switch elements configured to connect one of K touch electrodes, which are connectable to each of the M sensor sensing units, to a corresponding sensor sensing unit, and
K is a number of touch electrodes which are connectable to each of the M sensor sensing units at different points in time, and is equal to N/M.

11. The touch display device of claim 10 , wherein the front multiplexer turns on some of the switch elements on the basis of register values stored in a switch enable register.

12. The touch display device of claim 11 , wherein the front multiplexer changes a location of a first touch electrode row of the sensing active region in units of rows in response to updating of the register values stored in the switch enable register.

13. The touch display device of claim 1 , wherein the sensing active region is changed in units of rows such that a touch occurrence location is included in the sensing active region.

14. A touch driving circuit, comprising:
a sensor sensing unit block configured to sense two or more touch electrodes from among N touch electrodes included in a touch panel; and
a front multiplexer configured to select two or more touch electrodes from among the N touch electrodes, and to connect the two or more touch electrodes to the sensor sensing unit block,
wherein the sensor sensing unit block comprises M sensor sensing units, M is greater than or equal to 2, and N is greater than M,
wherein the front multiplexer is configured to select M touch electrodes disposed in a sensing active region corresponding to a first sensing period from among the N touch electrodes, and to match and connect the M touch electrodes and the M sensor sensing units,
wherein the M sensor sensing units are configured to simultaneously sense the M touch electrodes disposed in the sensing active region during the first sensing period, and
wherein the front multiplexer comprises:
a first-multiplexer configured to select the 2M touch electrodes from among the N touch electrodes, and to set a differential sensing region;
M second-multiplexers corresponding to the M sensor sensing units, and configured to group the 2M touch electrodes into M touch electrode pairs; and
M third-multiplexers corresponding to the M sensor sensing units, and configured to selectively connect two touch electrodes included in each of the M touch electrode pairs to a sensing input end and a reference input end of a differential amplifier included in each of the M sensor sensing units.

15. The touch driving circuit of claim 14 , wherein each of the M sensor sensing units comprises a differential amplifier having a sensing input end and a reference input end,
the front multiplexer is configured to:
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Assignees

• Lg Display Co Ltd

Inventors

• Kim Kiyong
• Kang Hyeongwon
• Jo Youngwoo
• Lee Hongju

Classifications

• G06F3/0443 Primary

  using a single layer of sensing electrodes · CPC title

• G06F2203/04104

  Multi-touch detection in digitiser, i.e. details about the simultaneous detection of a plurality of touching locations, e.g. multiple fingers or pen and finger · CPC title

• G06F3/04166 Primary

  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

• G06F3/0412

  Digitisers structurally integrated in a display · CPC title

• G06F3/044

  by capacitive means · CPC title