Display device with touch panel

• US 20090009486A1
• Filed: 06/06/2008
• Published: 01/08/2009
• Est. Priority Date: 07/03/2007
• Status: Active Grant

• Current Assignee: Paneltouch Technologies LLC (Touch Display LLC)
• Original Assignee: Hitachi Displays Limited (Japan Display Incorporated)
• Inventors: Sato, Hideo, Nishitani, Shigeyuki, Saito, Teruaki
• Granted Patent: US 8,451,234 B2
• Time in Patent Office: Days
• US Class Current: 345/174
• CPC Class Codes: G02F 1/13338 Input devices, e.g. touch panels
• 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 3/0445 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

A touch panel includes plural first electrodes extending in a first direction, plural second electrodes extending in a second direction different from the first direction, a driving circuit, a detection circuit, and a coordinate-position calculating circuit. The driving circuit sequentially selects two first electrodes out of the plural first electrodes, supplies a high potential voltage higher than a reference voltage to one of the selected two first electrodes, and supplies the reference voltage to the other, the detection circuit detects a capacitance difference (A-B) between a capacitor A between a selected one of the second electrodes and the first electrode to which the high potential voltage is supplied and a capacitor B between the selected second electrode and the first electrode to which the reference voltage is supplied, and the coordinate-position calculating circuit calculates a touch position on the touch panel touched by the observer on the basis of positions of the selected first and second electrodes and the capacitance difference (A-B).

Claims

1. A display device with touch panel comprising:

a display panel; and

an electrostatic capacitance coupling type touch panel arranged on a surface on an observer side of the display panel,

the touch panel including;

plural first electrodes extending in a first direction;

plural second electrodes extending in a second direction different from the first direction;

a driving circuit;

a detection circuit; and

a coordinate-position calculating circuit that calculates a touch position on the touch panel touched by the observer, wherein

the driving circuit sequentially selects two first electrodes out of the plural first electrodes, supplies a high potential voltage higher than a reference voltage to one of the selected two first electrodes, and supplies the reference voltage to the other,

the detection circuit selects at least one second electrode out of the plural second electrodes and detects a capacitance difference (A-B) between a capacitor A between the selected second electrode and the first electrode to which the high potential voltage is supplied and a capacitor B between the selected second electrode and the first electrode to which the reference voltage is supplied, and

the coordinate-position calculating circuit calculates a touch position on the touch panel touched by the observer on the basis of positions of the selected first and second electrodes and the capacitance difference (A-B).

2. A display device with touch panel according to claim 1, wherein the selected two first electrodes are adjacent two of the first electrodes.

3. A display device with touch panel according to claim 1, wherein

the detection circuit has an integration circuit, and

the integration circuit integrates a current difference between an electric current flowing through the capacitor A and an electric current flowing through the capacitor B and outputs a voltage proportional to the capacitance difference (A-B).

4. A display device with touch panel according to claim 3, wherein

the detection circuit sequentially selects the second electrodes in a time division manner, and

the integration circuit integrates a current difference between an electric current flowing through a capacitor A between the sequentially selected second electrodes and the first electrode to which the high potential voltage is supplied and an electric current flowing through a capacitor B between the sequentially selected second electrodes and the first electrode to which the reference voltage is supplied and outputs a voltage proportional to the capacitance difference (A-B).

5. A display device with touch panel according to claim 3, wherein

the detection circuit simultaneously selects the plural second electrodes,

the integration circuit is provided for each of the plural second electrodes, and

each of the integration circuits integrates a current difference between an electric current flowing through a capacitor A between the second electrode corresponding to each of the integration circuits and the first electrode to which the high potential voltage is supplied and an electric current flowing through a capacitor B between the second electrode corresponding to each of the integration circuits and the first electrode to which the reference voltage is supplied and outputs a voltage proportional to the capacitance difference (A-B).

14. A display device with touch panel according to claim 3, wherein the detection circuit has an A/D conversion circuit connected to a post stage of the integration circuit.

17. A display device with touch panel according to claim 1, wherein

each of the first electrodes has a wide electrode pattern between the adjacent two second electrodes, and

each of the second electrodes has a wide electrode pattern between the adjacent two first electrodes.

18. A display device with touch panel according to claim 1, wherein the display device is an IPS type liquid crystal display device.

6. A display device with touch panel comprising:

a display panel; and

an electrostatic capacitance coupling type touch panel arranged on a surface on an observer side of the display panel,

the touch panel including;

plural first electrodes extending in a first direction;

plural second electrodes extending in a second direction different from the first direction;

a driving circuit;

a detection circuit; and

a coordinate-position calculating circuit that calculates a touch position on the touch panel touched by the observer, wherein

the driving circuit sequentially selects, in a period A, two first electrodes out of the plural first electrodes, supplies a high potential voltage higher than a reference voltage to one of the selected two first electrodes, and supplies the reference voltage to the other and sequentially selects, in a period B, two second electrodes out of the plural second electrodes, supplies the high potential voltage higher than the reference voltage to one of the selected two second electrodes, and supplies the reference voltage to the other,

the detection circuit detects, in the period A, a capacitance difference (A-B) between a capacitor A between each of the second electrodes and the first electrode to which the high potential voltage is supplied and a capacitor B between each of the second electrodes and the first electrode to which the reference voltage is supplied and detects, in the period B, a capacitance difference (C-D) between a capacitor C between each of the first electrodes and the second electrode to which the high potential voltage is supplied and a capacitor D between each of the first electrodes and the second electrode to which the reference voltage is supplied, and

the coordinate-position calculating circuit calculates a touch position on the touch panel by the observer on the basis of the selected first electrode and the capacitance difference (A-B) and the selected second electrode and the capacitance difference (C-D).

7. A display device with touch panel according to claim 6, wherein the two first electrodes selected in the period A are adjacent two of the first electrodes and the two second electrodes selected in the period B are adjacent two of the second electrodes.

8. A display device with touch panel according to claim 6, wherein

the detection circuit has an integration circuit, and

the integration circuit integrates, in the period A, a current difference between an electric current flowing through the capacitor A and an electric current flowing through the capacitor B and outputs a voltage proportional to the capacitance difference (A-B) and integrates, in the period B, a current difference between an electric current flowing through the capacitance C and an electric current flowing through the capacitor D and outputs a voltage proportional to the capacitance difference (C-D).

15. A display device with touch panel according to claim 8, wherein the detection circuit has an AID conversion circuit connected to a post stage of the integration circuit.

9. A display device with touch panel comprising:

a display panel; and

an electrostatic capacitance coupling type touch panel arranged on a surface on an observer side of the display panel,

the touch panel including;

plural first electrodes extending in a first direction;

plural second electrodes extending in a second direction different from the first direction;

a first electrode selection circuit;

a second electrode selection circuit;

a detection circuit; and

a coordinate-position calculating circuit that calculates a touch position on the touch panel touched by the observer, wherein

the first electrode selection circuit sequentially selects, in a period A, two first electrodes out of the plural first electrodes, supplies a high potential positive polarity pulse having a voltage level higher than a reference voltage to one of the selected two first electrodes, and supplies a low potential negative polarity pulse having a voltage level lower than the reference voltage to the other,

the second electrode selection circuit sequentially selects, in a period B, two second electrodes out of the plural second electrodes, supplies a high potential positive polarity pulse having a voltage level higher than the reference voltage to one of the selected two second electrodes, and supplies a low potential negative polarity pulse having a voltage level lower than the reference voltage to the other,

the detection circuit detects, in the period A, a capacitance difference (A-B) between a capacitor A between each of the second electrodes and the first electrode to which the positive polarity pulse is supplied and a capacitor B between each of the second electrodes and the first electrode to which the negative polarity pulse is supplied and detects, in the period B, a capacitance difference (C-D) between a capacitor C between each of the first electrodes and the second electrode to which the positive polarity pulse is supplied and a capacitor D between each of the first electrodes and the second electrode to which the negative polarity pulse is supplied, and

the coordinate-position calculating circuit calculates a touch position on the touch panel by the observer on the basis of the selected first electrode and the capacitance difference (A-B) and the selected second electrode and the capacitance difference (C-D).

10. A display device with touch panel according to claim 9, wherein the two first electrodes selected in the period A are adjacent two of the first electrodes and the two second electrodes selected in the period B are adjacent two of the second electrodes.

11. A display device with touch panel according to claim 9, wherein the two first electrodes selected in the period A are the first electrode serving as a reference and the other first electrode and the two second electrodes selected in the period B are the second electrode serving as a reference and the other second electrode.

12. A display device with touch panel according to claim 9 wherein

the first electrode selection circuit supplies the reference voltage to each of the first electrodes in the period B, and

the second electrode selection circuit supplies the reference voltage to each of the second electrodes in the period A.

13. A display device with touch panel according to claim 9, wherein

the detection circuit has an integration circuit, and

the integration circuit integrates, in the period A, a current difference between an electric current flowing through the capacitor A and an electric current flowing through the capacitor B and outputs a voltage proportional to the capacitance difference (A-B) and integrates, in the period B, a current difference between an electric current flowing through the capacitor C and an electric current flowing through the capacitor D and outputs a voltage proportional to the capacitance difference (C-D).

16. A display device with touch panel according to claim 13, wherein the detection circuit has an A/D conversion circuit connected to a post stage of the integration circuit.

19. A display device with touch panel according to claim 10, wherein

the first electrode selection circuit supplies the reference voltage to each of the first electrodes in the period B, and

the second electrode selection circuit supplies the reference voltage to each of the second electrodes in the period A.

20. A display device with touch panel according to claim 11, wherein

the first electrode selection circuit supplies the reference voltage to each of the first electrodes in the period B, and

the second electrode selection circuit supplies the reference voltage to each of the second electrodes in the period A.