Touch screen liquid crystal display

• US 8,243,027 B2
• Filed: 06/08/2007
• Issued: 08/14/2012
• Est. Priority Date: 06/09/2006
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Hotelling, Steve Porter, Chen, Wei, Krah, Christoph Horst, Elias, John Greer, Zhong, John Z., Hodge, Andrew Bert, Land, Brian Richards, Yao, Wei Hsin, Boer, Willem den
• Primary Examiner(s): Eisen, Alexander
• Assistant Examiner(s): MARINELLI, PATRICK
• Application Number:
  US11/760,060
• Publication Number:
  US 20080062148A1
• Time in Patent Office: 1,894 Days
• Field of Search: 345156-184, 345/104, 178 1801- 2004, 349/162, 349/12
• 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. A touch screen comprising a liquid crystal display with integral touch sensing, 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;

a liquid crystal layer disposed between the first and second substrates;

a plurality of pixel electrodes disposed on the first substrate;

a plurality of touch drive electrodes disposed between the liquid crystal layer and the second substrates and extending in a first direction, the plurality of touch drive electrodes providing a driving voltage waveform during a touch sensing mode of operation;

a plurality of touch sense electrodes disposed between the liquid crystal layer and the second substrates and extending in a second direction, transverse to the first direction;

a counter electrode disposed between the liquid crystal layer and the second substrate, wherein the counter electrode is segmented and comprises one of the plurality of touch drive electrodes or the plurality of touch sense electrodes;

the plurality of touch drive electrodes and the plurality of touch sense electrodes being operative during the touch sensing mode of operation, the counter electrode operative to provide a common voltage waveform, different from the driving voltage waveform, during a display mode of operation;

the plurality of touch drive electrodes and the plurality of touch sense electrodes being spaced apart from one another to form capacitive coupling nodes therebetween; and

at least one capacitance sensing circuit operatively coupled to the plurality of touch sense electrodes during the touch sensing mode of operation for measuring a change in current and/or voltage resulting from a change in capacitance at the capacitive coupling nodes.

2. The touch screen of claim 1 wherein the plurality of touch drive electrodes are disposed on the second substrate;

and the plurality of touch sense electrodes comprises a segmented conductive black matrix.

3. The touch screen of claim 1 wherein the plurality of touch drive electrodes serve as the counter electrode during the display mode of operation.

4. The touch screen of claim 1 wherein the plurality of touch drive electrodes are disposed on the second substrate;

and the plurality of touch sense electrodes comprises a non-transparent metal layer disposed behind a black matrix.

5. The touch screen of claim 4 wherein the plurality of touch drive electrodes are configured to serves as the counter electrode during the display mode of operation.

6. The touch screen of claim 1 wherein at least during the touch sensing mode of operation, the plurality of touch drive electrodes are operative to sequentially transmit a stimulus waveform having a periodic voltage along one or multiple ones of the plurality of touch drive electrodes to the capacitive coupling nodes.

7. The touch screen of claim 1 wherein the plurality of touch sense electrodes comprise a segmented conductive black matrix.

8. The touch screen of claim 1, wherein:

the plurality of touch sense electrodes are disposed directly on the second substrate;

a dielectric layer is disposed directly on the plurality of touch sense electrodes; and

the plurality of touch drive electrodes are disposed directly on the dielectric layer.

9. The touch screen of claim 8, wherein the capacitance sensing circuit comprises a charge amplifier and the plurality of touch sense electrodes are coupled to an input of the charge amplifier.

10. The touch screen of claim 9, wherein the charge amplifier has an output, an inverting input and a non-inverting input and a feedback path between the output and inverting input, and the plurality of touch sense electrodes are coupled to the inverting input of the charge amplifier.

11. The touch screen of claim 10, wherein at least during the touch sensing mode of operation, the plurality of touch drive electrodes are operative to sequentially transmit a stimulus waveform having a periodic voltage along one or multiple ones of the touch drive electrodes to the capacitive coupling nodes.

12. The touch screen of claim 11, wherein the plurality of touch sense electrodes comprises a segmented conductive black matrix.

13. The touch screen of claim 11, wherein the plurality of touch sense electrodes comprises a non-transparent metal layer disposed behind a polymer black matrix.

14. The touch screen of claim 8, further comprising primary color sections disposed directly on the second substrate and in between ones of the plurality of sense electrodes.

15. The touch screen of claim 1, further comprising an active TFT layer disposed on the second substrate and coupled at least to one of the plurality of touch drive electrodes and the plurality of touch sense electrodes.

16. The touch screen of claim 1, wherein:

the plurality of touch sense electrodes are disposed directly on the second substrate;

a planarization layer is disposed on the plurality of touch sense electrodes; and

the plurality of touch drive electrodes are disposed on the planarization layer.

17. The touch screen of claim 16, wherein the plurality of touch drive electrodes are also used for V_COM during the display mode of operation.

18. The touch screen of claim 17, wherein a color filter is disposed between the plurality of touch sense electrodes and the planarization layer.

19. The touch screen of claim 1, wherein:

the plurality of touch drive electrodes are disposed directly on the second substrate;

a planarization layer is disposed on the plurality of touch drive electrodes; and

the plurality of touch sense electrodes are disposed on the planarization layer.

20. The touch screen of claim 19, wherein the plurality of touch sense electrodes are also used for V_COM during the display mode of operation.

21. The touch screen of claim 20 wherein the touch drive electrodes comprise resistance reducing metal segments.

22. The touch screen of claim 20 further comprising a plurality of guard traces configured to block a portion of an electric field between the touch drive electrodes and the touch sense electrodes.

23. The touch screen of claim 20, wherein a color filter is disposed between the plurality of touch drive electrodes and the planarization layer.

24. The touch screen of claim 16, wherein at least during the touch sensing mode of operation, the plurality of touch drive electrodes are operative to sequentially transmit a stimulus waveform having a periodic voltage along one or multiple ones of the touch drive electrodes to the capacitive coupling nodes.

25. The touch screen of claim 24, wherein a color filter is disposed between the plurality of touch sense electrodes and the planarization layer.

26. The touch screen of claim 19, wherein at least during the touch sensing mode of operation, the plurality of touch drive electrodes are operative to sequentially transmit a stimulus waveform having a periodic voltage along one or multiple ones of the touch drive electrodes to the capacitive coupling nodes.

27. The touch screen of claim 26, wherein a color filter is disposed between the plurality of touch drive electrodes and the planarization layer.

28. The touch screen of claim 1, wherein the counter electrode is segmented such that one region of the display is keep at a constant Vcom during the display mode of operation, while another region is independently scanned for touches during the touch sensing mode of operation.

29. The touch screen of claim 28, wherein at least during the touch sensing mode of operation, the plurality of touch drive electrodes are operative to sequentially transmit a stimulus waveform having a periodic voltage along one or multiple ones of the plurality of touch drive electrodes to the capacitive coupling nodes.

30. 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;

a liquid crystal layer disposed between the first and second substrates;

a plurality of pixel electrodes disposed on the first substrate;

a plurality of touch drive electrodes disposed between the liquid crystal layer and the second substrates and extending in a first direction, the plurality of touch drive electrodes providing a driving voltage waveform during a touch sensing mode of operation;

a plurality of touch sense electrodes disposed between the liquid crystal layer and the second substrates and extending in a second direction, transverse to the first direction;

a counter electrode disposed between the liquid crystal layer and the second substrate, wherein the counter electrode is segmented and comprises one of the plurality of touch drive electrodes or the plurality of touch sense electrodes;

the plurality of touch drive electrodes and the plurality of touch sense electrodes being operative during the touch sensing mode of operation, the counter electrode operative to provide a common voltage waveform, different from the driving voltage waveform, during a display mode of operation;

the plurality of touch drive electrodes and the plurality of touch sense electrodes being spaced apart from one another to form capacitive coupling nodes therebetween; and

at least one capacitance sensing circuit operatively coupled to the plurality of touch sense electrodes during the touch sensing mode of operation for measuring a change in current and/or voltage resulting from a change in capacitance at the capacitive coupling nodes.

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

32. The electronic device of claim 30 wherein the electronic device comprises at least one of a handheld computer, a personal digital assistant, a media player, and a mobile telephone.

33. The touch screen of claim 30 wherein the plurality of touch drive electrodes are disposed on the second substrate;

and the plurality of touch sense electrodes comprises a segmented conductive black matrix.

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

35. The electronic device of claim 33 wherein the electronic device comprises at least one of a handheld computer, a personal digital assistant, a media player, and a mobile telephone.

36. The touch screen of claim 30 wherein the plurality of touch drive electrodes are disposed on the second substrate;

and the plurality of touch sense electrodes comprises a non-transparent metal layer disposed behind a black matrix.

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

38. The electronic device of claim 36 wherein the electronic device comprises at least one of a handheld computer, a personal digital assistant, a media player, and a mobile telephone.

39. The electronic device of claim 30, wherein the plurality of touch drive electrodes serve as the counter electrode during the display mode of operation.

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

41. The electronic device of claim 39 wherein the electronic device comprises at least one of a handheld computer, a personal digital assistant, a media player, and a mobile telephone.

42. The electronic device of claim 30, wherein at least during the touch sensing mode of operation, the plurality of touch drive electrodes are operative to sequentially transmit a stimulus waveform having a periodic voltage along one or multiple ones of the plurality of touch drive electrodes to the capacitive coupling nodes.

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

44. The electronic device of claim 42 wherein the electronic device comprises at least one of a handheld computer, a personal digital assistant, a media player, and a mobile telephone.

45. The electronic device of claim 30, wherein:

the plurality of touch sense electrodes are disposed directly on the second substrate;

a dielectric layer is disposed directly on the plurality of touch sense electrodes; and

the plurality of touch drive electrodes are disposed directly on the dielectric layer.

46. The electronic device of claim 45, wherein the capacitance sensing circuit comprises a charge amplifier and the plurality of touch sense electrodes are coupled to an input of the charge amplifier.

47. The electronic device of claim, 46 wherein the charge amplifier has an output, an inverting input and a non-inverting input and a feedback path between the output and inverting input, and the plurality of touch sense electrodes are coupled to the inverting input of the charge amplifier.

48. The electronic device of claim, 47 wherein at least during the touch sensing mode of operation, the plurality of touch drive electrodes are operative to sequentially transmit a stimulus waveform having a periodic voltage along one or multiple ones of the touch drive electrodes to the capacitive coupling nodes.

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

50. The electronic device of claim 48 wherein the electronic device comprises at least one of a handheld computer, a personal digital assistant, a media player, and a mobile telephone.

51. The electronic device of claim 30, further comprising an active TFT layer disposed on the second substrate and coupled at least to one of the plurality of touch drive electrodes and the plurality of touch sense electrodes.

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

53. The electronic device of claim 51 wherein the electronic device comprises at least one of a handheld computer, a personal digital assistant, a media player, and a mobile telephone.

54. The electronic device of claim 30, wherein:

the plurality of touch sense electrodes are disposed directly on the second substrate;

a planarization layer is disposed on the plurality of touch sense electrodes; and

the plurality of touch drive electrodes are disposed on the planarization layer.

55. The electronic device of claim 54 wherein the electronic device is selected from the group consisting of a desktop computer, a tablet computer, and a notebook computer.

56. The electronic device of claim 54 wherein the electronic device comprises at least one of a handheld computer, a personal digital assistant, a media player, and a mobile telephone.

57. The electronic device of claim 54, wherein a color filter is disposed between the plurality of touch sense electrodes and the planarization layer.

58. The electronic device of claim 57 wherein the electronic device is selected from the group consisting of a desktop computer, a tablet computer, and a notebook computer.

59. The electronic device of claim 57 wherein the electronic device comprises at least one of a handheld computer, a personal digital assistant, a media player, and a mobile telephone.

60. The electronic device of claim 30, wherein:

the plurality of touch drive electrodes are disposed directly on the second substrate;

a planarization layer is disposed on the plurality of touch drive electrodes; and

the plurality of touch sense electrodes are disposed on the planarization layer.

61. The electronic device of claim 60 wherein the electronic device is selected from the group consisting of a desktop computer, a tablet computer, and a notebook computer.

62. The electronic device of claim 60 wherein the electronic device comprises at least one of a handheld computer, a personal digital assistant, a media player, and a mobile telephone.

63. The electronic device of claim 60, wherein the plurality of touch sense electrodes are also used for V_COM during the display mode of operation.

64. The electronic device of claim 63, wherein a color filter is disposed between the plurality of touch drive electrodes and the planarization layer.

65. The electronic device of claim 30, wherein the counter electrode is segmented such that one region of the display is kept at a constant V_COM during the display mode of operation, while another region is independently scanned for touches during the touch sensing mode of operation.

66. 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;

a liquid crystal layer disposed between the first and second substrates;

a plurality of pixel electrodes disposed on the first substrate;

a plurality of touch drive electrodes disposed between the liquid crystal layer and the second substrates and extending in a first direction, the plurality of touch drive electrodes providing a driving voltage during a touch sensing mode of operation;

a plurality of touch sense electrodes disposed between the liquid crystal layer and the second substrates and extending in a second direction, transverse to the first direction;

a counter electrode disposed between the liquid crystal layer and the second substrate, wherein the counter electrode is segmented and comprises one of the plurality of touch drive electrodes or the plurality of touch sense electrodes;

the plurality of touch drive electrodes and the plurality of touch sense electrodes being operative during the touch sensing mode of operation, the counter electrode operative to provide a common voltage waveform, different from the driving voltage waveform, during a display mode of operation;

the plurality of touch drive electrodes and the plurality of touch sense electrodes being spaced apart from one another to form capacitive coupling nodes therebetween; and

at least one capacitance sensing circuit operatively coupled to the plurality of touch sense electrodes during the touch sensing mode of operation for measuring a change in current and/or voltage resulting from a change in capacitance at the capacitive coupling nodes.

67. The mobile telephone of claim 66, wherein the plurality of touch drive electrodes are disposed on the second substrate;

and the plurality of touch sense electrodes comprises a segmented conductive black matrix.

68. The mobile telephone of claim 66, wherein the plurality of touch drive electrodes are disposed on the second substrate;

and the plurality of touch sense electrodes comprises a non-transparent metal layer disposed behind a black matrix.

69. The mobile telephone of claim 68, wherein the plurality of touch drive electrodes are configured to serves as the counter electrode during the display mode of operation.

70. The mobile telephone of claim 66, wherein at least during the touch sensing mode of operation, the plurality of touch drive electrodes are operative to sequentially transmit a stimulus waveform having a periodic voltage along one or multiple ones of the plurality of touch drive electrodes to the capacitive coupling nodes.

71. The mobile telephone of claim 66, wherein:

the plurality of touch sense electrodes are disposed directly on the second substrate;

a dielectric layer is disposed directly on the plurality of touch sense electrodes; and

the plurality of touch drive electrodes are disposed directly on the dielectric layer.

72. The mobile telephone of claim 71, wherein the capacitance sensing circuit comprises a charge amplifier and the plurality of touch sense electrodes are coupled to an input of the charge amplifier.

73. The mobile telephone of claim 72, wherein the charge amplifier has an output, an inverting input and a non-inverting input and a feedback path between the output and inverting input, and the plurality of touch sense electrodes are coupled to the inverting input of the charge amplifier.

74. The mobile telephone of claim 73, wherein at least during the touch sensing mode of operation, the plurality of touch drive electrodes are operative to sequentially transmit a stimulus waveform having a periodic voltage along one or multiple ones of the touch drive electrodes to the capacitive coupling nodes.

75. The mobile telephone of claim 74, wherein the plurality of touch sense electrodes comprises a segmented conductive black matrix.

76. The mobile telephone of claim 74, wherein the plurality of touch sense electrodes comprises a non-transparent metal layer disposed behind a polymer black matrix.

77. The mobile telephone of claim 71, further comprising primary color sections disposed directly on the second substrate and in between ones of the plurality of sense electrodes.

78. The mobile telephone of claim 66, further comprising an active TFT layer disposed on the second substrate and coupled at least to one of the plurality of touch drive electrodes and the plurality of touch sense electrodes.

79. The mobile telephone of claim 66 wherein:

the plurality of touch sense electrodes are disposed directly on the second substrate;

a planarization layer is disposed on the plurality of touch sense electrodes; and

the plurality of touch drive electrodes are disposed on the planarization layer.

80. The mobile telephone of claim 79, wherein the plurality of touch drive electrodes are also used for V_COM during the display mode of operation.

81. The mobile telephone of claim 80, wherein a color filter is disposed between the plurality of touch sense electrodes and the planarization layer.

82. The mobile telephone of claim 66, wherein:

the plurality of touch drive electrodes are disposed directly on the second substrate;

a planarization layer is disposed on the plurality of touch drive electrodes; and

the plurality of touch sense electrodes are disposed on the planarization layer.

83. The mobile telephone of claim 82, wherein the plurality of touch sense electrodes are also used for V_COM during the display mode of operation.

84. The mobile telephone as recited in claim 83, wherein a color filter is disposed between the plurality of touch drive electrodes and the planarization layer.

85. The mobile telephone of claim 79, wherein at least during the touch sensing mode of operation, the plurality of touch drive electrodes are operative to sequentially transmit a stimulus waveform having a periodic voltage along one or multiple ones of the touch drive electrodes to the capacitive coupling nodes.