Touch sensor, display with touch sensor, and method for generating position data

• US 20040217945A1
• Filed: 02/20/2004
• Published: 11/04/2004
• Est. Priority Date: 08/22/2001
• Status: Active Grant

• Current Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.), Omron Corporation
• Original Assignee: Sharp Kabushiki Kaisha (Hon Hai Precision Industry Co., Ltd.)
• Inventors: Nakano, Toshihisa, Miyamoto, Saburo
• Granted Patent: US 8,031,180 B2
• Time in Patent Office: Days
• US Class Current: 345/173
• CPC Class Codes: G02F 1/13338 Input devices, e.g. touch panels
• CPC Class Codes: G06F 2203/04113 Peripheral electrode pattern in resistive digitisers, i.e. electrodes at the periphery of the resistive sheet are shaped in patterns enhancing linearity of induced field
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/0443 using a single layer of sensing electrodes
• CPC Class Codes: G06F 3/0444 using a single conductive element covering the whole sensing surface, e.g. by sensing the electrical current flowing at the corners
• CPC Class Codes: G06F 3/045 using resistive elements, e.g. a single continuous surface or two parallel surfaces put in contact

Abstract

A display device with a touch sensor according to the present invention includes an active matrix substrate 4A and a transparent counter electrode 7. On a first surface of the active matrix substrate, multiple pixel electrodes are arranged in matrix. The transparent counter electrode is opposed to the first surface of the active matrix substrate. The display device further includes a first circuit, a second circuit and a switching circuit. The first circuit supplies a voltage or a current to the transparent counter electrode for display purposes. The second circuit detects currents flowing from a number of points on the transparent counter electrode. And the switching circuit selectively connects electrically one of the first and second circuits to the transparent counter electrode.

Claims

1. A display device with a touch sensor, the display device comprising:

an active-matrix substrate including multiple pixel electrodes that are arranged in matrix on a first surface thereof; and

a transparent counter electrode, which is opposed to the first surface of the active-matrix substrate,

wherein the display device further includes;

a first circuit for supplying a voltage or current to the transparent counter electrode for display purposes;

a second circuit for detecting currents flowing from multiple points on the transparent counter electrode; and

a switching circuit for selectively connecting electrically one of the first and second circuits to the transparent counter electrode.

2. The display device with the touch sensor of claim 1, wherein the switching circuit periodically switches the electrical connection of the first or second circuit to the transparent counter electrode in response to a control signal.

3. The display device with the touch sensor of claim 1, wherein at least a portion of the first circuit, at least a portion of the second circuit, and the switching circuit each include a thin-film transistor that is provided on the active-matrix substrate.

4. The display device with the touch sensor of claim 3, wherein the thin-film transistor includes polysilicon that is deposited on the active-matrix substrate.

5. The display device with the touch sensor of claim 3, wherein the transparent counter electrode includes a plurality of divided areas, and wherein a current flowing between both ends of each said area is detected by the second circuit.

6. The display device with the touch sensor of claim 1, further comprising a liquid crystal layer between the pixel electrodes and the transparent counter electrode.

7. The display device with the touch sensor of claim 6, wherein the transparent counter electrode is provided on another substrate that faces the substrate, and wherein the liquid crystal layer is sealed between the two substrates.

8. The display device with the touch sensor of claim 1, further comprising an organic EL layer between the pixel electrodes and the transparent counter electrode.

9. A display device with a touch sensor, the display device comprising:

a first substrate including multiple scanning electrodes that are arranged on a first surface thereof; and

a second substrate including multiple data electrodes that are opposed to the first surface of the first substrate,

wherein the display device further includes;

a first circuit for supplying a voltage or current to each said data electrode for display purposes;

a second circuit for detecting currents flowing from multiple points on each said data electrode; and

a switching circuit for selectively connecting electrically one of the first and second circuits to the data electrode.

11. The display device with the touch sensor of claim 9, wherein at least a portion of the first circuit, at least a portion of the second circuit, and the switching circuit each include a thin-film transistor that is provided on the substrate.

12. The display device with the touch sensor of claim 11, wherein the thin-film transistor includes polysilicon that is deposited on the substrate.

13. The display device with the touch sensor of claim 9, further comprising a liquid crystal layer between the first and second substrates.

10. A display device with a touch sensor, the display device comprising:

a first substrate including a first group of electrodes that are arranged on a first surface thereof; and

a second substrate including a second group of electrodes that are opposed to the first surface of the first substrate,

wherein the display device further includes;

a first circuit for supplying a voltage or current to each said electrode of the first group for display purposes;

a second circuit for detecting currents flowing from multiple points on each said electrode of the first group; and

a switching circuit for selectively connecting electrically one of the first and second circuits to the electrode of the first group.

36. The display device with the touch sensor of claim 10, wherein at least a portion of the first circuit, at least a portion of the second circuit, and the switching circuit each include a thin-film transistor that is provided on the substrate.

37. The display device with the touch sensor of claim 36, wherein the thin-film transistor includes polysilicon that is deposited on the substrate.

38. The display device with the touch sensor of claim 10, further comprising a liquid crystal layer between the first and substrates.

14. A display device with a touch sensor, the display device comprising:

a display medium having a display plane with a two-dimensional area;

driving means for generating an electric field in a selected portion of the display medium; and

location sensing means for locating a point of external contact on a plane, which is defined parallel to the display plane, by an electrostatic capacitive coupling technique,

wherein the driving means includes a transparent electrode, and

wherein the location sensing means is electrically connected to multiple points of the transparent electrode, thereby detecting a current associated with the point of contact.

15. A touch sensor for locating an external input point on an operating plane, which expands in an X direction and in a Y direction, by an electrostatic capacitive coupling technique, the touch sensor comprising:

a first location sensing transparent conductive film, which is provided parallel to the operating plane and which is electrically connected to a Y coordinate detecting conductive portion for detecting a coordinate of the input point in the Y direction;

a second location sensing transparent conductive film, which is provided so as to face the first location sensing transparent conductive film and which is electrically connected to an X coordinate detecting conductive portion for detecting a coordinate of the input point in the X direction;

a dielectric layer, which is provided between the first and second location sensing transparent conductive films; and

a switching circuit for selectively applying a predetermined voltage to one of the first and second location sensing transparent conductive films.

16. The touch sensor of claim 15, wherein the switching circuit makes one of the first and second location sensing transparent conductive films electrically continuous alternately.

17. The touch sensor of claim 15, further comprising a detector circuit for calculating the coordinate of the input point in the Y direction based on the amount of current flowing between the input point and the Y coordinate detecting conductive portion and the coordinate of the input point in the X direction based on the amount of current flowing between the input point and the X coordinate detecting conductive portion, respectively.

18. The touch sensor of claim 15, wherein the Y coordinate detecting conductive portion is provided on the first location sensing transparent conductive film and includes at least two conductive portions, which are spaced apart from each other in the Y direction, and wherein the X coordinate detecting conductive portion is provided on the second location sensing transparent conductive film and includes at least two conductive portions, which are spaced apart from each other in the X direction.

19. The touch sensor of claim 15, wherein the dielectric layer is made of polyethylene terephthalate.

20. The touch sensor of claim 15, wherein the dielectric layer is made of glass.

21. The touch sensor of claim 15, wherein glass is provided on a principal surface of the first or second location sensing transparent conductive film, the principal surface being opposite from the dielectric layer, and wherein the input point is defined by way of the glass.

22. A display device comprising:

the touch sensor of claim 15;

and a display panel, of which the display plane is provided with the touch sensor.

23. The display device with the touch sensor of claim 22, wherein the display panel includes:

a display medium layer;

an electrode, which is provided closer to a viewer than the display medium layer is and which drives the display medium layer; and

an insulating layer, which is provided even closer to the viewer than the electrode is, and

wherein a selected one of the first and second location sensing transparent conductive films is provided so as to face the electrode with the insulating layer interposed between them, and

wherein by applying a periodically changing oscillating voltage to the electrode, an induced voltage, and eventually an electric field, are generated in the selected location sensing transparent conductive film, and

wherein in accordance with a variation in the current to be produced by forming a point of contact on the first and second location sensing transparent conductive films, location data is generated for the point of contact.

24. A display device comprising:

the touch sensor of claim 15;

an active-matrix substrate, which is provided so as to face a selected one of the first and second location sensing transparent conductive films with the display medium layer interposed between them;

a display circuit for supplying a voltage or current to the selected location sensing transparent conductive film for display purposes while the predetermined voltage is not applied thereto;

a detector circuit for detecting currents flowing from multiple points on the selected location sensing transparent conductive film; and

another switching circuit for selectively connecting one of the display and detector circuits electrically to the selected location sensing transparent conductive film.

25. A display device with a touch sensor, the display device comprising:

a display panel including a display medium layer, an electrode provided closer to a viewer than the display medium layer is so as to drive the display medium layer, and an insulating layer provided even closer to the viewer than the electrode is;

a location sensing transparent conductive film, which is provided so as to face the electrode with the insulating layer interposed between them; and

a detector circuit for detecting variations in currents flowing from multiple points on the location sensing transparent conductive film,

wherein by applying a periodically changing oscillating voltage to the electrode, an induced voltage, and eventually an electric field, are generated in the location sensing transparent conductive film, and

wherein in accordance with the variations in the currents to be produced by forming a point of contact on the location sensing transparent conductive film, location data is generated for the point of contact.

26. The display device with the touch sensor of claim 25, wherein the induced voltage is a pulse wave that has local maximum values and/or local minimum values periodically.

27. The display device with the touch sensor of claim 25, wherein the oscillating voltage is used to drive the display medium layer.

28. The display device with the touch sensor of claim 25, further comprising:

a display circuit for supplying a voltage or current to the electrode so as to drive the display medium layer; and

a switching circuit for selectively connecting electrically one of the display and detector circuits to the electrode.

29. The display device with the touch sensor of claim 27, wherein the display panel is a liquid crystal panel, and wherein the oscillating voltage is a voltage of which the polarities invert periodically.

30. The display device with the touch sensor of claim 29, wherein the liquid crystal panel is an active-matrix-addressed liquid crystal panel, and wherein the electrode is a transparent counter electrode.

31. The display device with the touch sensor of claim 25, wherein the distance between the electrode and the location sensing transparent conductive film is about 1 mm or less.

32. The display device with the touch sensor of claim 26, wherein the pulse wave has a frequency of about 40 kHz.

39. The display device with the touch sensor of claim 28, wherein the display panel is a liquid crystal panel, and wherein the oscillating voltage is a voltage of which the polarities invert periodically.

40. The display with the touch sensor of claim 39, wherein the liquid crystal panel is an active-matrix-addressed liquid crystal panel, and wherein the electrode is a transparent counter electrode.

41. the display device with the touch sensor of claim 27, wherein the pulse wave has a frequency of about 40 kHz.

42. the display device with the touch sensor of claim 28, wherein the pulse wave has a frequency of about 40 kHz.

43. The display device with the touch sensor of claim 31, wherein the pulse wave has a frequency of about 40 kHz.

33. A method of generating location data for a point of contact on a location sensing transparent conductive film, which is provided so as to face an electrode with an insulating layer interposed between them, the method comprising the steps of:

applying a periodically changing oscillating voltage to the electrode, thereby generating an induced voltage, and eventually an electric field, in the location sensing transparent conductive film; and

generating location data for the point of contact in accordance with variations in currents to be produced by forming the point of contact on the location sensing transparent conductive film.

34. The location data generating method of claim 33, wherein the electrode is used to drive a display medium layer of a display panel.

35. The location data generating method of claim 33, wherein the oscillating voltage is used to drive the display medium layer of the display panel.