TOUCH SCREEN LIQUID CRYSTAL DISPLAY

• US 20080062139A1
• Filed: 06/08/2007
• Published: 03/13/2008
• Est. Priority Date: 06/09/2006
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Krah, Christoph, Boer, Willem, Yao, Wei, Hotelling, Steve, Chen, Wei, Hodge, Andrew, Zhong, John, Elias, John, Land, Brian
• Granted Patent: US 8,552,989 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 2203/04103 Manufacturing, i.e. details related to manufacturing processes specially suited for touch sensitive devices
• CPC Class Codes: G06F 2203/04112 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 Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/04164 Connections between sensors and controllers, e.g. routing lines between electrodes and connection pads
• 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 3/04184 Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally
• 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 3/0445 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 herein are liquid-crystal display (LCD) touch screens that integrate the touch sensing elements with the display circuitry. The integration may take a variety of forms. Touch sensing elements can be completely implemented within the LCD stackup but outside the not between the color filter plate and the array plate. Alternatively, some touch sensing elements can be between the color filter and array plates with other touch sensing elements not between the plates. In another alternative, all touch sensing elements can be between the color filter and array plates. The latter alternative can include both conventional and in-plane-switching (IPS) LCDs. In some forms, one or more display structures can also have a touch sensing function. Techniques for manufacturing and operating such displays, as well as various devices embodying such displays are also disclosed.

Claims

1. An integrated liquid crystal display touch screen comprising:

a first polarizer;

a second polarizer;

a first substrate having display control circuitry formed thereon, the first substrate being disposed between the first polarizer and the second polarizer;

a second substrate disposed between the first polarizer and the second polarizer and adjacent the first substrate; and

at least one touch sensing element disposed between the first and second substrate.

2. The touch screen of claim 1 wherein the second substrate has a color filter disposed thereon.

3. The touch screen of claim 1 wherein the at least one touch sensing element disposed between the first and second substrates comprises a plurality of touch drive electrodes formed on the second substrate.

4. The touch screen of claim 3 wherein the plurality of touch drive electrodes comprise ITO patterned on top of a color filter.

5. The touch screen of claim 3 wherein the touch drive electrodes are configured to be used for display V_COM.

6. The touch screen of claim 4 further comprising a plurality of touch sense electrodes disposed between the first polarizer and the second polarizer and not between the first and second substrates.

7. The touch screen of claim 6 wherein the plurality of touch sense electrodes are formed on the second substrate.

8. The touch screen of claim 3 wherein the plurality of touch drive electrodes comprise ITO patterned directly on the second substrate and wherein a color filter is deposited on top of the plurality of electrodes.

9. The touch screen of claim 8 further comprising a plurality of touch sense electrodes disposed between the first polarizer and the second polarizer but not between the first and second substrates.

10. The touch screen of claim 9 wherein the plurality of touch sense electrodes are formed on the second substrate.

11. The touch screen of claim 8 further comprising an ITO layer deposited on top of the color filter, wherein the ITO layer comprises display V_COM.

12. The touch screen of claim 3 further comprising at least one touch sensing element disposed between the first polarizer and the second polarizer but not between the first and second substrates.

13. The touch screen of claim 12 wherein the at least one touch sensing element disposed between the first polarizer and the second polarizer but not between the first and second substrates comprises a plurality of touch electrodes formed on the second substrate.

14. The touch screen of claim 1 wherein the at least one touch sensing element disposed between the first and second substrates comprises a conductive black matrix segmented into a plurality of touch drive electrodes.

15. The touch screen of claim 14 further comprising a plurality of touch sense electrodes disposed between the first polarizer and the second polarizer but not between the first and second substrates.

16. The touch screen of claim 14 wherein the plurality of touch sense electrodes are formed on the second substrate.

17. The touch screen of claim 1 wherein the at least one touch sensing element disposed between the first and second substrates comprises a plurality of metal touch drive electrodes disposed behind a black matrix.

18. The touch screen of claim 17 further comprising a plurality of touch sense electrodes disposed between the first polarizer and the second polarizer but not between the first and second substrates.

19. The touch screen of claim 17 wherein the plurality of touch sense electrodes are formed on the second substrate.

20. The touch screen of claim 1 wherein the at least one touch sensing element disposed between the first and second substrates comprises a plurality of ITO drive pixels on the first substrate.

21. The touch screen of claim 20 further comprising a plurality of sense electrodes deposited on the first polarizer, wherein the first polarizer is laminated to the first substrate.

22. The touch screen of claim 20 wherein the ITO drive pixels are also used for display pixel drive.

23. The touch screen of claim 1 wherein the at least one touch sensing element disposed between the first and second substrates comprises a plurality of touch drive electrodes formed on the first substrate, wherein the plurality of touch drive electrodes also form electrodes for display pixel storage capacitors.

24. The touch screen of claim 23 further comprising a plurality of sense electrodes deposited on the first polarizer, wherein the first polarizer is laminated to the first substrate.

25. The touch screen of claim 23 wherein the ITO drive pixels are also used for display pixel drive.

26. An electronic device incorporating an integrated liquid crystal display touch screen, the touch screen comprising:

a first polarizer;

a second polarizer;

a first substrate having display control circuitry formed thereon, the first substrate being disposed between the first polarizer and the second polarizer;

a second substrate disposed between the first polarizer and the second polarizer and adjacent the first substrate; and

at least one touch sensing element disposed between the first and second substrate.

27. The electronic device of claim 26 wherein the electronic device is selected from the group consisting of a desktop computer, a tablet computer, and a notebook computer.

28. The electronic device of claim 26 wherein the electronic device comprises at least one of a handheld computer, a personal digital assistant, a media player, and a mobile telephone.

29. The electronic device of claim 26 wherein the at least one touch sensing element disposed between the first and second substrates comprises a plurality of touch drive electrodes formed on the second substrate.

30. The electronic device of claim 29 wherein the electronic device is selected from the group consisting of a desktop computer, a tablet computer, and a notebook computer.

31. The electronic device of claim 29 wherein the electronic device comprises at least one of a handheld computer, a personal digital assistant, a media player, and a mobile telephone.

32. The electronic device of claim 29 wherein the touch drive electrodes are configured to be used for display V_COM.

33. The electronic device of claim 32 wherein the electronic device is selected from the group consisting of a desktop computer, a tablet computer, and a notebook computer.

34. The electronic device of claim 32 wherein the electronic device comprises at least one of a handheld computer, a personal digital assistant, a media player, and a mobile telephone.

35. The electronic device of claim 29 wherein the plurality of touch drive electrodes comprise ITO patterned directly on the second substrate and wherein a color filter is deposited on top of the plurality of electrodes.

36. The electronic device of claim 35 wherein the electronic device is selected from the group consisting of a desktop computer, a tablet computer, and a notebook computer.

37. The electronic device of claim 35 wherein the electronic device comprises at least one of a handheld computer, a personal digital assistant, a media player, and a mobile telephone.

38. The electronic device of claim 26 wherein the at least one touch sensing element disposed between the first and second substrates comprises a conductive black matrix segmented into a plurality of touch drive electrodes.

39. The electronic device of claim 38 wherein the electronic device is selected from the group consisting of a desktop computer, a tablet computer, and a notebook computer.

40. The electronic device of claim 38 wherein the electronic device comprises at least one of a handheld computer, a personal digital assistant, a media player, and a mobile telephone.

41. The electronic device of claim 26 wherein the at least one touch sensing element disposed between the first and second substrates comprises a plurality of metal touch drive electrodes disposed behind a black matrix.

42. The electronic device of claim 41 wherein the electronic device is selected from the group consisting of a desktop computer, a tablet computer, and a notebook computer.

43. The electronic device of claim 41 wherein the electronic device comprises at least one of a handheld computer, a personal digital assistant, a media player, and a mobile telephone.

44. The electronic device of claim 26 wherein the at least one touch sensing element disposed between the first and second substrates comprises a plurality of ITO drive pixels on the first substrate.

45. The electronic device of claim 44 wherein the electronic device is selected from the group consisting of a desktop computer, a tablet computer, and a notebook computer.

46. The electronic device of claim 44 wherein the electronic device comprises at least one of a handheld computer, a personal digital assistant, a media player, and a mobile telephone.

47. The electronic device of claim 44 wherein the ITO drive pixels are also used for display pixel drive.

48. The electronic device of claim 47 wherein the electronic device is selected from the group consisting of a desktop computer, a tablet computer, and a notebook computer.

49. The electronic device of claim 47 wherein the electronic device comprises at least one of a handheld computer, a personal digital assistant, a media player, and a mobile telephone.

50. The electronic device of claim 26 wherein the at least one touch sensing element disposed between the first and second substrates comprises a plurality of touch drive electrodes formed on the first substrate, wherein the plurality of touch drive electrodes also form electrodes for display pixel storage capacitors.

51. The electronic device of claim 50 wherein the electronic device is selected from the group consisting of a desktop computer, a tablet computer, and a notebook computer.

52. The electronic device of claim 50 wherein the electronic device comprises at least one of a handheld computer, a personal digital assistant, a media player, and a mobile telephone.

53. A mobile telephone incorporating an integrated liquid crystal display touch screen, the touch screen comprising:

a first polarizer;

a second polarizer;

a first substrate having display control circuitry formed thereon, the first substrate being disposed between the first polarizer and the second polarizer;

a second substrate disposed between the first polarizer and the second polarizer and adjacent the first substrate; and

at least one touch sensing element disposed between the first and second substrate.

54. The mobile telephone of claim 53 wherein the at least one touch sensing element disposed between the first and second substrates comprises a plurality of touch drive electrodes formed on the second substrate.

55. The mobile telephone of claim 54 wherein the touch drive electrodes are configured to be used for display V_COM.

56. The mobile telephone of claim 54 wherein the plurality of touch drive electrodes comprise ITO patterned directly on the second substrate and wherein a color filter is deposited on top of the plurality of electrodes.

57. The mobile telephone of claim 53 wherein the at least one touch sensing element disposed between the first and second substrates comprises a conductive black matrix segmented into a plurality of touch drive electrodes.

58. The mobile telephone of claim 53 wherein the at least one touch sensing element disposed between the first and second substrates comprises a plurality of metal touch drive electrodes disposed behind a black matrix.

59. The mobile telephone of claim 53 wherein the at least one touch sensing element disposed between the first and second substrates comprises a plurality of ITO drive pixels on the first substrate.

60. The mobile telephone of claim 59 wherein the ITO drive pixels are also used for display pixel drive.

61. The mobile telephone of claim 53 wherein the at least one touch sensing element disposed between the first and second substrates comprises a plurality of touch drive electrodes formed on the first substrate, wherein the plurality of touch drive electrodes also form electrodes for display pixel storage capacitors.

62. A method of operating an integrated liquid crystal display touch screen whereby updating of the display can be done concurrently with touch scanning, the method comprising:

dividing touch-sensing circuitry of the touch screen into a plurality of drive segments, each drive segment overlapping one or more display rows;

updating the display at a predetermined refresh rate;

stimulating the plurality of drive segments at a predetermined scan rate; and

changing the sequence of stimulating the plurality of drive segments as required to prevent simultaneously stimulating a drive segment that overlaps a display row currently being updated.

63. The method of claim 62 wherein the scan rate is the same as the refresh rate.

64. The method of claim 62 wherein the scan rate is an integer multiple of the refresh rate.

65. The method of claim 64 wherein the scan rate is twice the refresh rate.

66. The method of claim 62 further comprising changing the sequence of stimulating the plurality of drive segments as required to prevent concurrently stimulating a drive segment that is adjacent a display row currently being updated.

67. A method of manufacturing an integrated liquid crystal display touch screen, the method comprising:

processing a first substrate, wherein processing the first substrate comprises;

applying a first ITO layer to the first substrate;

etching the first ITO layer;

applying a second ITO layer;

processing a second substrate, wherein processing the second substrate comprises;

forming one or more touch-sensing structures on the second substrate

affixing the first substrate to the second substrate to form an LCD assembly; and

affixing one or more touch-sensing elements to the LCD assembly.

68. The method of claim 67 wherein the one or more touch-sensing structures on the second substrate comprise one or more drive circuits.

69. The method of claim 67 wherein the one or more touch-sensing structures on the second substrate comprise one or more sense circuits.

70. The method of claim 67 wherein the one or more touch-sensing elements affixed to the LCD assembly are selected from the group consisting of integrated circuits, flexible printed circuits, and discrete components.

71. The method of claim 67 wherein processing the first substrate further comprises patterning the second ITO layer photolithography.

72. The method of claim 67 wherein processing the first substrate further comprises etching the second ITO layer.

73. The method of claim 67 wherein processing the first substrate further comprises applying a third ITO layer.

74. The method of claim 73 wherein a resistance of the third ITO layer is reduced by adding metal traces aligned with a black matrix of the LCD.