Apparatus for driving touch panel and display apparatus comprising the same

• US 8,988,385 B2
• Filed: 12/29/2011
• Issued: 03/24/2015
• Est. Priority Date: 08/12/2011
• Status: Active Grant

• Current Assignee: Industry-University Cooperation Foundation Hanyang University, LG Display Co., Ltd.
• Original Assignee: Industry-University Cooperation Foundation Hanyang University, LG Display Co., Ltd.
• Inventors: Kwon, Oh Kyong, Seo, Seong Mo, Cha, Dong Hoon, Yang, Ik Seok
• Primary Examiner(s): Awad, Amr
• Assistant Examiner(s): LUI, DONNA V
• Application Number:
  US13/339,901
• Publication Number:
  US 20130038570A1
• Time in Patent Office: 1,181 Days
• Field of Search: None
• US Class Current: 345/174
• CPC Class Codes: G06F 3/0416 Control or interface arrangements specially adapted for digitisers
• CPC Class Codes: G06F 3/0443 using a single layer of sensing electrodes
• CPC Class Codes: G06F 3/0445 using two or more layers of sensing electrodes, e.g. using two layers of electrodes separated by a dielectric layer
• 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 are a touch panel driving apparatus and a display device including the same, which lead to the enhancement of sensing sensitivity. The touch panel driving apparatus includes a touch control unit and a touch sensing unit. The touch sensing unit is connected to the receiving lines, and generates the digital touch information on the basis of change of a capacitance between two transmitting lines and one receiving line or generates the digital touch information on the basis of change of a capacitance of each of the receiving lines to supply the digital touch information to the touch control unit, according to the sensing control signal.

Claims

1. A touch panel driving apparatus comprising:

a touch control unit generating a sensing control signal corresponding to a first or second sensing mode, and generating touch point information on the basis of input digital touch information, the first or second sensing mode being set for a touch panel which comprises a plurality of intersected transmitting lines and receiving lines; and

a touch sensing unit connected to the receiving lines, and generating the digital touch information on the basis of change of a capacitance between two transmitting lines and one receiving line according to the sensing control signal based on the first sensing mode or generating the digital touch information on the basis of change of a capacitance of each of the receiving lines to supply the digital touch information to the touch control unit according to the sensing control signal based on the second sensing mode,

wherein in the first sensing mode, the capacitance between the two transmitting lines and one receiving line is changed by mutually inverted first and second excitation signals which are respectively and directly applied to the two transmitting lines at the same time,

wherein the touch sensing unit comprises;

a control signal generator generating a reset control signal and mutually inverted first and second switching control signals which respectively correspond to a reset section, sensing section, and digital conversion section of a line sensing period on the basis of the sensing control signal based on the first sensing mode;

an excitation supplier generating the mutually inverted first and second excitation signals on the basis of the sensing control signal based on the first sensing mode;

a sensing circuit unit comprising a plurality of sensing circuits which generate mutually inverted first and second differential amplification signals on the basis of the change of the capacitance between the two transmitting lines and one receiving line based on the mutually inverted first and second excitation signals, in response to the reset control signal and mutually inverted first and second switching control signals;

a multiplexer selectively outputting the mutually inverted first and second differential amplification signals supplied from the sensing circuits, according to a channel selection signal of the touch control unit; and

a converter converting the mutually inverted first and second differential amplification signals, outputted from the multiplexer, into the digital touch information to supply the digital touch information to the touch control unit.

2. The touch panel driving apparatus of claim 1, wherein,

a high voltage section and a low voltage section of the first excitation signal are repeated by a certain time unit during the sensing section, and

the low voltage section of the first excitation signal is maintained during sections other than the sensing section.

3. The touch panel driving apparatus of claim 1, wherein each of the sensing circuits comprises:

a first input terminal connected to the receiving line;

a second input terminal receiving a reference voltage signal;

a node connector connecting the first input terminal to one of a first and a second output node and connecting the second input terminal to the other output node, in response to the mutually inverted first and second switching control signals; and

a differential amplifier unit initialized according to the reset control signal, and generating the mutually inverted first and second differential amplification signals according to two input signals which are respectively inputted to an inverting input terminal and a non-inverting input terminal through the node connector.

4. The touch panel driving apparatus of claim 3, wherein,

during the reset section, the node connector connects the first input terminal to the first output node and simultaneously connects the second input terminal to the second output node, in response to the mutually inverted first and second switching control signals,

during the sensing section, the node connector alternately connects the first and second input terminals to the first and second output nodes, in response to the mutually inverted first and second switching control signals, and

during the digital conversion section, the node connector connects the first input terminal to the second output node and simultaneously connects the second input terminal to the first output node, in response to the mutually inverted first and second switching control signals.

5. The touch panel driving apparatus of claim 3, wherein the differential amplifier unit comprises:

a differential amplifier comprising the inverting input terminal connected to the first output node, the non-inverting input terminal connected to the second output node, a non-inverting output terminal outputting the first differential amplification signal, and an inverting output terminal outputting the second differential amplification signal;

a first feedback capacitor connected between the non-inverting output terminal and the inverting input terminal;

a first reset switch parallelly connected to the first feedback capacitor, and initializing the first feedback capacitor during the reset section according to the reset control signal;

a second feedback capacitor connected between the inverting output terminal and the non-inverting input terminal; and

a second reset switch parallelly connected to the second feedback capacitor, and initializing the second feedback capacitor during the reset section according to the reset control signal.

6. The touch panel driving apparatus of claim 1, wherein,

the control signal generator generates the reset control signal and the mutually inverted first and second switching control signals which respectively correspond to the reset section, sensing section, and digital conversion section of the line sensing period on the basis of the sensing control signal based on the second sensing mode;

the excitation signal supplier generates an excitation signal on the basis of the sensing control signal based on the second sensing mode; and

the plurality of sensing circuits generates the mutually inverted first and second differential amplification signals according to the capacitance change of the receiving line based on the excitation signal, in response to the reset control signal and the mutually inverted first and second switching control signals.

7. The touch panel driving apparatus of claim 6, wherein,

the excitation signal comprises a third excitation signal supplied to odd-numbered sensing circuits of the sensing circuits, and a fourth excitation signal supplied to even-numbered sensing circuits of the sensing circuits,

the third excitation signal is maintained at a voltage level higher than a voltage level of a reference voltage signal, only during the sensing section and digital conversion section of an odd-numbered line sensing period for an odd-numbered receiving line, and

the fourth excitation signal is maintained at the voltage level higher than the voltage level of the reference voltage signal, only during the sensing section and digital conversion section of an even-numbered line sensing period for an even-numbered receiving line.

8. The touch panel driving apparatus of claim 6, wherein each of the sensing circuits comprises:

a first input terminal connected to the receiving line;

a second input terminal receiving the excitation signal;

a node connector connecting the first input terminal to one of a first and a second output node and connecting the second input terminal to the other output node, in response to the mutually inverted first and second switching control signals; and

a differential amplifier unit initialized according to the reset control signal, and generating the mutually inverted first and second differential amplification signals according to two input signals which are respectively inputted to an inverting input terminal and a non-inverting input terminal through the node connector.

9. The touch panel driving apparatus of claim 8, wherein,

only during an odd-numbered line sensing period, the node connector of an odd-numbered sensing circuit of the sensing circuits connects the first input terminal to the first output node and simultaneously connects the second input terminal to the second output node, and

only during even-numbered line sensing period, the node connector of an even-numbered sensing circuit of the sensing circuits connects the first input terminal to the first output node and simultaneously connects the second input terminal to the second output node.

10. The touch panel driving apparatus of claim 8, wherein the differential amplifier unit comprises:

a differential amplifier comprising the inverting input terminal connected to the first output node, the non-inverting input terminal connected to the second output node, a non-inverting output terminal outputting the first differential amplification signal, and an inverting output terminal outputting the second differential amplification signal;

a first feedback capacitor connected between the non-inverting output terminal and the inverting input terminal;

a first reset switch parallelly connected to the first feedback capacitor, and initializing the first feedback capacitor during the reset section according to the reset control signal;

a second feedback capacitor connected between the inverting output terminal and the non-inverting input terminal; and

a second reset switch parallelly connected to the second feedback capacitor, and initializing the second feedback capacitor during the reset section according to the reset control signal.

11. A display device comprising:

a display panel;

a display panel driver displaying an image on the display panel;

a touch panel disposed on the display panel or formed inside the display panel; and

a touch panel driving apparatus driving the touch panel,

wherein the touch panel driving apparatus comprises;

a touch control unit generating a sensing control signal corresponding to a first or second sensing mode, and generating touch point information on the basis of input digital touch information, the first or second sensing mode being set for a touch panel which comprises a plurality of intersected transmitting lines and receiving lines; and

a touch sensing unit connected to the receiving lines, and generating the digital touch information on the basis of change of a capacitance between two transmitting lines and one receiving line according to the sensing control signal based on the first sensing mode or generating the digital touch information on the basis of change of a capacitance of each of the receiving lines to supply the digital touch information to the touch control unit according to the sensing control signal based on the second sensing mode,

wherein in the first sensing mode, the capacitance between the two transmitting lines and one receiving line is changed by mutually inverted first and second excitation signals which are respectively and directly applied to the two transmitting lines at the same time,

wherein the touch sensing unit comprises;

a control signal generator generating a reset control signal and mutually inverted first and second switching control signals which respectively correspond to a reset section, sensing section, and digital conversion section of a line sensing period on the basis of the sensing control signal based on the first sensing mode;

an excitation signal supplier generating the mutually inverted first and second excitation signals on the basis of the sensing control signal based on the first sensing mode;

a sensing circuit unit comprising a plurality of sensing circuits which generate mutually inverted first and second differential amplification signals on the basis of the change of the capacitance between the two transmitting lines and one receiving line based on the mutually inverted first and second excitation signals, in response to the reset control signal and mutually inverted first and second switching control signals;

a multiplexer selectively outputting the mutually inverted first and second differential amplification signals supplied from the sensing circuits, according to a channel selection signal of the touch control unit; and

a converter converting the mutually inverted first and second differential amplification signals, outputted from the multiplexer, into the digital touch information to supply the digital touch information to the touch control unit.

12. The display device of claim 11, wherein each of the sensing circuits comprises:

a first input terminal connected to the receiving line;

a second input terminal receiving a reference voltage signal;

a node connector connecting the first input terminal to one of a first and a second output node and connecting the second input terminal to the other output node, in response to the mutually inverted first and second switching control signals; and

a differential amplifier unit initialized according to the reset control signal, and generating the mutually inverted first and second differential amplification signals according to two input signals which are respectively inputted to an inverting input terminal and a non-inverting input terminal through the node connector.

13. The display device of claim 11, wherein the touch control unit generates a touch sync signal which is synchronized with a source output enable signal for displaying an image by a horizontal line unit of the display panel, and drives the touch sensing unit after about 5μ

s elapses from a falling edge point of the touch sync signal.

14. The display device of claim 12, wherein,

during the reset section, the node connector connects the first input terminal to the first output node and simultaneously connects the second input terminal to the second output node, in response to the mutually inverted first and second switching control signals,

during the sensing section, the node connector alternately connects the first and second input terminals to the first and second output nodes, in response to the mutually inverted first and second switching control signals, and

during the digital conversion section, the node connector connects the first input terminal to the second output node and simultaneously connects the second input terminal to the first output node, in response to the mutually inverted first and second switching control signals.

15. The display device of claim 12, wherein the differential amplifier unit comprises:

a differential amplifier comprising the inverting input terminal connected to the first output node, the non-inverting input terminal connected to the second output node, a non-inverting output terminal outputting the first differential amplification signal, and an inverting output terminal outputting the second differential amplification signal;

a first feedback capacitor connected between the non-inverting output terminal and the inverting input terminal;

a first reset switch parallelly connected to the first feedback capacitor, and initializing the first feedback capacitor during the reset section according to the reset control signal;

a second feedback capacitor connected between the inverting output terminal and the non-inverting input terminal; and

a second reset switch parallelly connected to the second feedback capacitor, and initializing the second feedback capacitor during the reset section according to the reset control signal.

16. The display device of claim 11, wherein,

the control signal generator generates the reset control signal and the mutually inverted first and second switching control signals which respectively correspond to the reset section, sensing section, and digital conversion section of the line sensing period on the basis of the sensing control signal based on the second sensing mode;

the excitation signal supplier generates an excitation signal on the basis of the sensing control signal based on the second sensing mode; and

the plurality of sensing circuits generates the mutually inverted first and second differential amplification signals according to the capacitance change of the receiving line based on the excitation signal, in response to the reset control signal and the mutually inverted first and second switching control signals.

17. The display device of claim 16, wherein,

the excitation signal comprises a third excitation signal supplied to odd-numbered sensing circuits of the sensing circuits, and a fourth excitation signal supplied to even-numbered sensing circuits of the sensing circuits,

the third excitation signal is maintained at a voltage level higher than a voltage level of a reference voltage signal, only during the sensing section and digital conversion section of an odd-numbered line sensing period for an odd-numbered receiving line, and

the fourth excitation signal is maintained at the voltage level higher than the voltage level of the reference voltage signal, only during the sensing section and digital conversion section of an even-numbered line sensing period for an even-numbered receiving line.

18. The display device of claim 16, wherein each of the sensing circuits comprises:

a first input terminal connected to the receiving line;

a second input terminal receiving the excitation signal;

a node connector connecting the first input terminal to one of a first and a second output node and connecting the second input terminal to the other output node, in response to the mutually inverted first and second switching control signals; and

a differential amplifier unit initialized according to the reset control signal, and generating the mutually inverted first and second differential amplification signals according to two input signals which are respectively inputted to an inverting input terminal and a non-inverting input terminal through the node connector.

19. The display device of claim 18, wherein,

only during an odd-numbered line sensing period, the node connector of an odd-numbered sensing circuit of the sensing circuits connects the first input terminal to the first output node and simultaneously connects the second input terminal to the second output node, and

only during an even-numbered line sensing period, the node connector of an even-numbered sensing circuit of the sensing circuits connects the first input terminal to the first output node and simultaneously connects the second input terminal to the second output node.

20. The display device of claim 18, wherein the differential amplifier unit comprises:

a differential amplifier comprising the inverting input terminal connected to the first output node, the non-inverting input terminal connected to the second output node, a non-inverting output terminal outputting the first differential amplification signal, and an inverting output terminal outputting the second differential amplification signal;

a first feedback capacitor connected between the non-inverting output terminal and the inverting input terminal;

a first reset switch parallelly connected to the first feedback capacitor, and initializing the first feedback capacitor during the reset section according to the reset control signal;

a second feedback capacitor connected between the inverting output terminal and the non-inverting input terminal; and

a second reset switch parallelly connected to the second feedback capacitor, and initializing the second feedback capacitor during the reset section according to the reset control signal.