Touch display device, touch driving circuit and touch driving method thereof

Patent metadata

Field	Value
Publication number	US-11079876-B2
Application number	US-202017115558-A
Country	US
Kind code	B2
Filing date	Dec 8, 2020
Priority date	Dec 31, 2019
Publication date	Aug 3, 2021
Grant date	Aug 3, 2021

Abstract

Embodiments of the present disclosure relate to a touch display device, a touch driving circuit, and a touch driving method, and more specifically, to a touch display device, a touch driving circuit, and a touch driving method for enabling a signal-to-noise ratio (SNR) and sensitivity of touch sensing to be improved by implementing a code division sensing effect for the self-capacitance sensing scheme.

First claim

The invention claimed is:

1. A touch display device, comprising:
a touch panel including a plurality of touch electrodes and a plurality of touch lines;
a multiplexer connected to the touch electrodes through the touch lines, the multiplexer configured to output a code division sensing signal obtained by adding, in a code division form, touch sensing signals provided from touch electrodes of the plurality of touch electrodes that are selected by a code division control signal; and
a touch sensing circuit configured to:
calculate capacitances in the plurality of touch electrodes based on the code division sensing signal from the multiplexer, and
detect a touch presence or a touch coordinate.

2. The touch display device according to claim 1 , wherein the touch panel is configured to be operated based on a self-capacitance touch sensing method, in which a touch driving signal and a touch sensing signal are provided through a same touch line of the plurality of touch lines that is connected to a touch electrode of the plurality of touch electrodes.

3. The touch display device according to claim 1 , wherein the multiplexer includes a plurality of multiplexers, to each of which a sub-plurality of touch electrodes from the plurality of touch electrodes is connected as one group.

4. The touch display device according to claim 1 , wherein the touch sensing circuit including:
a preamplifier circuit including:
an operational amplifier configured to receive the code division sensing signal through an inverting input terminal of the operational amplifier, the operational amplifier configured to receive a touch driving signal through an non-inverting input terminal of the operational amplifier,
a feedback capacitor connected in parallel between the inverting input terminal and an output terminal of the operational amplifier, and
a feedback switch;

an integrating circuit including a plurality of switches and a plurality of capacitors, the integrating circuit configured to accumulate output voltages from the preamplifier circuit; and
a sampling circuit configured to provide an output signal from the integrating circuit at any time.

5. The touch display device according to claim 4 , wherein the touch driving signal is a sine wave signal including a plurality of frequency components.

6. The touch display device according to claim 4 , wherein the touch driving signal has a first peak-to-peak value different from a second peak-to-peak value of a load-free driving signal that is applied to the plurality of touch electrodes through the multiplexer.

7. The touch display device according to claim 1 , wherein the touch sensing circuit is configured to calculate the capacitances in the plurality of touch electrodes using a decoding code corresponding to an inverse matrix of the code division control signal.

8. A touch driving circuit, comprising:
a multiplexer connected to a plurality of touch electrodes through a plurality of touch lines, the multiplexer, in operation, outputting a code division sensing signal obtained by adding, in a code division form, touch sensing signals provided from touch electrodes of the plurality of touch electrodes that are selected by a code division control signal; and
a touch sensing circuit, in operation, calculating capacitances in the plurality of touch electrodes based on the code division sensing signal from the multiplexer, the touch sensing circuit, in operation, detecting a touch presence or a touch coordinate.

9. The touch driving circuit according to claim 8 , wherein the multiplexer includes a plurality of multiplexers, to each of which a sub-plurality of touch electrodes from the plurality of touch electrodes is connected as one group.

10. The touch driving circuit according to claim 8 , wherein the touch sensing circuit including:
a preamplifier circuit including:
an operational amplifier, in operation, receiving the code division sensing signal through an inverting input terminal of the operational amplifier,
a feedback capacitor connected in parallel between the inverting input terminal and an output terminal of the operational amplifier, and
a feedback switch,
wherein a touch driving signal is applied to a non-inverting input terminal of the operational amplifier;

an integrating circuit including a plurality of switches and a plurality of capacitors, the integrating circuit, in operation, accumulating output voltages from the preamplifier circuit; and
a sampling circuit, in operation, providing an output signal from the integrating circuit at any time.

11. A touch driving method, comprising:
applying code division control signals to a multiplexer connected to a plurality of touch electrodes through a plurality of touch lines;
outputting a code division sensing signal, through the multiplexer, which are obtained by adding, in a code division form, touch sensing signals provided from touch electrodes of the plurality of touch electrodes that are selected by the code division control signal; and
detecting a touch presence or a touch coordinate by calculating capacitances in the plurality of touch electrodes based on the code division sensing signal from the multiplexer.

12. A touch display device, comprising:
a touch panel including a plurality of touch electrodes and a plurality of touch lines; and
a touch driving circuit for sensing the touch electrodes through the touch lines,
wherein the touch driving circuit includes a first multiplexer including n touch line channel ports, wherein the n is a natural number greater than or equal to 3,
wherein the n touch line channel ports are electrically connected to n touch electrodes through n touch lines, respectively, and
wherein during a first period of the touch panel, a touch driving signal is concurrently applied to (n−k) touch electrodes among the n touch electrodes connected with the n touch line channel ports and a load-free driving signal with a same phase to the touch driving signal is concurrently applied to k touch electrodes, wherein the k is a number smaller than n by 1 or more.

13. The touch display device according to claim 12 , wherein during a second period of the touch panel, the load-free driving signal is applied to at least one of the (n−k) touch electrodes to which the touch driving signal has been applied, and the touch driving signal is applied to at least one of k touch electrodes to which the load-free driving signal has been applied.

14. The touch display device according to claim 12 , wherein an amplitude of the touch driving signal is different from that of the load-free driving signal.

15. The touch display device according to claim 12 , further comprising a display panel including a plurality of data lines and a plurality of gate lines,
wherein during the first period of the touch panel, a gate load-free driving signal with a same phase to the touch driving signal is applied to gate lines of the plurality of gate lines that are overlapping with (n−k) touch electrodes to which the touch driving signal is applied, or during the first period of the touch panel, a data load-free driving signal with a same phase to the touch driving signal is applied to data lines of the plurality of data lines that are overlapping with (n−k) touch electrodes to which the touch driving signal is applied.

16. The touch display device according to claim 15 , wherein an amplitude of the gate load-free driving signal is different from that of the touch driving signal, or an amplitude of the data load-free driving signal is different from that of the touch driving signal.

17.

Assignees

• Lg Display Co Ltd

Inventors

• Jun Jaehun
• Kang Hyeongwon
• Shin Myungho

Classifications

• G06F2203/04112

  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 title

• G06F3/0446

  using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes · CPC title

• G06F3/041662 Primary

  using alternate mutual and self-capacitive scanning · CPC title

• G06F3/0443

  using a single layer of sensing electrodes · CPC title

• G06F3/0412

  Digitisers structurally integrated in a display · CPC title