Touch screen liquid crystal display

• US 8,654,083 B2
• Filed: 06/08/2007
• Issued: 02/18/2014
• Est. Priority Date: 06/09/2006
• Status: Expired due to Fees

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Hotelling, Steve Porter, Chen, Wei, Krah, Christoph Horst, Elias, John Greer, Yao, Wei Hsin, Zhong, John Z., Hodge, Andrew Bert, Land, Brian Richards, Boer, Willem den
• Primary Examiner(s): Eisen, Alexander
• Assistant Examiner(s): MARINELLI, PATRICK
• Application Number:
  US11/760,080
• Publication Number:
  US 20080062140A1
• Time in Patent Office: 2,447 Days
• Field of Search: 345156-173, 345/104, 349/141, 178 1801- 2003
• US Class Current: 345/173
• CPC Class Codes: G02F 1/13338 Input devices, e.g. touch panels
• CPC Class Codes: G02F 1/133514 Colour filters
• CPC Class Codes: G02F 1/133528 Polarisers
• CPC Class Codes: G02F 1/134309 characterised by their geometrical arrangement
• CPC Class Codes: G02F 1/134363 for applying an electric field parallel to the substrate, i.e. in-plane switching [IPS]
• CPC Class Codes: G02F 1/1362 Active matrix addressed cells G02F1/134336, G02F1/134363 take precedence
• CPC Class Codes: G02F 2201/124 interdigital
• CPC Class Codes: G06F 2203/04103 Manufacturing, i.e. details related to manufacturing processes specially suited for touch sensitive devices
• CPC Class Codes: G06F 2203/04104 Multi-touch detection in digitiser, i.e. details about the simultaneous detection of a plurality of touching locations, e.g. multiple fingers or pen and finger
• CPC Class Codes: G06F 2203/04111 Cross over in capacitive digitiser, i.e. details of structures for connecting electrodes of the sensing pattern where the connections cross each other, e.g. bridge structures comprising an insulating layer, or vias through substrate
• 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
• CPC Class Codes: G09G 2300/0426 Layout of electrodes and connections
• CPC Class Codes: G09G 2300/0439 : Pixel structures
• CPC Class Codes: G09G 2300/0456 : with a reflective area and a transmissive area combined in one pixel, such as in transflectance pixels
• CPC Class Codes: G09G 2300/0478 : related to liquid crystal pixels
• CPC Class Codes: G09G 2310/0205 : Simultaneous scanning of several lines in flat panels
• CPC Class Codes: G09G 3/3614 : Control of polarity reversal in general
• CPC Class Codes: G09G 3/3648 : using an active matrix G09G3/367 - G09G3/3696 take precedence

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 an in-plane-switching (IPS) liquid crystal display with integral touch sensing, the touch screen comprising:

a first substrate having display control circuitry formed thereon, the display control circuitry comprising a pair of electrodes for each display pixel, the pair of electrodes operative for in-plane-switching;

a second substrate adjacent the first substrate;

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

a plurality of touch sensing elements wherein each touch sensing element comprises a first electrode and a second electrode forming the pair of electrodes for each of the display pixels, the first electrode and the second electrode spaced apart from one another and operative in a display mode of operation and in a touch sensing mode of operation;

one or more transistors disposed on the first substrate for switching the mode of operation between the display mode of operation and the touch sensing mode of operation,

one or more gate lines exclusively for controlling the one or more transistors;

in the display mode of operation, for each pair of electrodes, the first electrode, serving as a common electrode and receiving a common voltage modulation signal, and the second electrode coupled to receive LCD display data over a display data line;

in a touch sensing mode of operation, for each pair of electrodes, the first electrode receiving a stimulation signal over a touch drive line, and the second electrode coupled to a capacitance measuring circuit over a touch sense line; and

wherein, for each pixel, the display data line, used for display data in the display mode of operation, is used as the touch sense line in the touch sensing mode of operation.

2. The touch screen of claim 1 wherein in the display mode of operation the common voltage modulation signal is applied to at least to a portion of the touch drive line.

3. The touch screen of claim 1 wherein the capacitance measuring circuitry comprises a charge amplifier.

4. The touch screen of claim 1 wherein the common voltage modulation signal has a periodic waveform of high frequency such that it does not negatively affect the display state of the liquid crystal layer.

5. The touch screen of claim 1 wherein the display is oriented with the second substrate positioned nearer a user than the first substrate.

6. The touch screen of claim 1 wherein the display is oriented with the first substrate positioned nearer a user than the second substrate.

7. The touch screen of claim 1, wherein a first plurality of first electrodes, forming pixels of a first type, are connected together to form a plurality of touch sense rows and a second plurality of first electrodes, forming pixels of a second type, are connected together to form a plurality of touch sense columns.

8. An electronic device incorporating an in-plane-switching (IPS) integrated liquid crystal display touch screen, the touch screen comprising:

a first substrate having display control circuitry formed thereon, the display circuitry comprising a pair of electrodes for each display pixel, the pair of electrodes operative for in-plane-switching;

a second substrate adjacent the first substrate;

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

a plurality of touch sensing elements wherein each touch sensing element comprises a first electrode and a second electrode forming the pair of electrodes for each of the display pixels, the first electrode and the second electrode spaced apart from one another and operative in a display mode of operation and in a touch sensing mode of operation;

one or more transistors disposed on the first substrate for switching the mode of operation between the display mode of operation and the touch sensing mode of operation,

one or more gate lines exclusively for controlling the one or more transistors;

in the display mode of operation, for each pair of electrodes, the at least first electrode, serving as a common electrode and receiving a common voltage modulation signal, and at least the second electrode coupled to receive LCD display data over a display data line;

in a touch sensing mode of operation, for each pair of electrodes, the first electrode receiving a stimulation signal over a touch drive line, and the second electrode coupled to a capacitance measuring circuit over a touch sense line; and

wherein, for each pixel, the display data line, used for display data in the display mode of operation, is used as the touch sense line in the touch sensing mode of operation.

9. The electronic device of claim 8 wherein the electronic device is selected from the group consisting of a desktop computer, a tablet computer, and a notebook computer.

10. The electronic device of claim 8 wherein the electronic device comprises at least one of a handheld computer, a personal digital assistant, a media player, and a mobile telephone.

11. The electronic device of claim 8 wherein the capacitance measuring circuit comprises a charge amplifier.

12. The electronic device of claim 11 wherein the electronic device is selected from the group consisting of a desktop computer, a tablet computer, and a notebook computer.

13. The electronic device of claim 11 wherein the electronic device comprises at least one of a handheld computer, a personal digital assistant, a media player, and a mobile telephone.

14. The electronic device of claim 8 wherein in the display mode of operation, common voltage modulation signal is applied to at least to a portion of the touch drive line, and wherein the common voltage modulation signal has a periodic waveform of high frequency such that it does not negatively affect a display state of the liquid crystal layer.

15. The electronic device of claim 14 wherein the electronic device is selected from the group consisting of a desktop computer, a tablet computer, and a notebook computer.

16. The electronic device of claim 14 wherein the electronic device comprises at least one of a handheld computer, a personal digital assistant, a media player, and a mobile telephone.

17. A mobile telephone incorporating an in-plane-switching (IPS) integrated liquid crystal display touch screen, the touch screen comprising:

a first substrate having display control circuitry formed thereon, the display circuitry comprising a pair of electrodes for each display pixel, the pair of electrodes operative for in-plane-switching;

a second substrate adjacent the first substrate;

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

a plurality of touch sensing elements wherein each touch sensing element comprises a first electrode and a second electrode forming the pair of electrodes for each of the display pixels, the first electrode and the second electrode spaced apart from one another and operative in a display mode of operation and in a touch sensing mode of operation;

one or more transistors disposed on the first substrate for switching the mode of operation between the display mode of operation and the touch sensing mode of operation,

one or more gate lines exclusively for controlling the one or more transistors;

in the display mode of operation, for each pair of electrodes, at least the first electrode, serving as a common electrode and receiving a common voltage modulation signal, and at least the second electrode coupled to receive LCD display data over a display data line;

in a touch sensing mode of operation, for each pair of electrodes, the first electrode receiving a stimulation signal over a touch drive line, and the second electrode coupled to a capacitance measuring circuit over a touch sense line; and

wherein, for each pixel, the display data line, used for display data in the display mode of operation, is used as the touch sense line in the touch sensing mode of operation.

18. The mobile telephone of claim 17 wherein the capacitance measuring circuitry comprises a charge amplifier.

19. The mobile telephone of claim 17, wherein in the display mode of operation, the common voltage modulation signal is applied to at least to a portion of the drive line, and wherein the common voltage modulation signal has a periodic waveform of high frequency such that it does not negatively affect the display state of the liquid crystal layer.

20. The mobile telephone of claim 17, wherein a first plurality of first electrodes, forming pixels of a first type, are connected together to form a plurality of touch sense rows and a second plurality of first electrodes, forming pixels of a second type, are connected together to form a plurality of touch sense columns.

21. A touch screen comprising an in-plane-switching (IPS) liquid crystal display with integral touch sensing, the touch screen comprising:

a first substrate having disposed thereon a pair of electrodes for each of a plurality of display pixels, the pair of electrodes operative for in-plane-switching;

a second substrate adjacent the first substrate;

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

a plurality of touch sensing elements, each touch sensing element comprising;

a first electrode, wherein the first electrode is one of the pair of electrodes for each of the plurality of display pixels;

a second electrode, wherein the second electrode is the other of the pair of electrodes for each of the plurality of display pixels;

one or more transistors adapted to switch the pair of electrodes between a display mode of operation and a touch mode of operation;

one or more gate lines exclusively for controlling the one or more transistors;

in the display mode of operation, for each pair of electrodes, the first electrode, serving as a common electrode and receiving a common voltage modulation signal, and the second electrode coupled to receive LCD display data over a display data line;

in a touch sensing mode of operation, for each pair of electrodes, the first electrode receiving a stimulation signal over a touch drive line, and the second electrode coupled to a capacitance measuring circuit over a touch sense line; and

wherein, for each pixel, the display data line, used for display data in the display mode of operation, is used as the touch sense line in the touch sensing mode of operation.

22. An electronic device incorporating an in-plane-switching (IPS) integrated liquid crystal display touch screen, the touch screen comprising:

a first substrate having disposed thereon a pair of electrodes for each of a plurality of display pixels, the pair of electrodes operative for in-plane-switching;

a second substrate adjacent the first substrate;

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

a plurality of touch sensing elements, each touch sensing element comprising;

a first electrode, wherein the first electrode is one of the pair of electrodes for each of the plurality of display pixels;

a second electrode, wherein the second electrode is the other of the pair of electrodes for each of the plurality of display pixels;

one or more transistors adapted to switch the pair of electrodes between a display mode of operation and a touch mode of operation;

one or more gate lines exclusively for controlling the one or more transistors;

in the display mode of operation, for each pair of electrodes, the first electrode, serving as a common electrode and receiving a common voltage modulation signal, and the second electrode coupled to receive LCD display data over a display data line;

in a touch sensing mode of operation, for each pair of electrodes, at least the first electrode receiving a stimulation signal over a touch drive line, and at least the second electrode coupled to a capacitance measuring circuit over a touch sense line; and

wherein, for each pixel, the display data line, used for display data in the display mode of operation, is used as the touch sense line in the touch sensing mode of operation.

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

a first substrate having disposed thereon a pair of electrodes for each of a plurality of display pixels, the pair of electrodes operative for in-plane-switching;

a second substrate adjacent the first substrate;

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

a plurality of touch sensing elements, each touch sensing element comprising;

a first electrode, wherein the first electrode is one of the pair of electrodes for each of the plurality of display pixels;

a second electrode, wherein the second electrode is the other of the pair of electrodes for each of the plurality of display pixels;

one or more transistors adapted to switch the pair of electrodes between a display mode of operation and a touch mode of operation;

one or more gate lines exclusively for controlling the one or more transistors;

in the display mode of operation, for each pair of electrodes, the first electrode, serving as a common electrode and receiving a common voltage modulation signal, and the second electrode coupled to receive LCD display data over a display data line;

in a touch sensing mode of operation, for each pair of electrodes, at least the first electrode receiving a stimulation signal over a touch drive line, and at least the second electrode coupled to a capacitance measuring circuit over a touch sense line; and

wherein, for each pixel, the display data line, used for display data in the display mode of operation, is used as the touch sense line in the touch sensing mode of operation.

24. A touch screen comprising an in-plane-switching (IPS) liquid crystal display with integral touch sensing, the touch screen comprising:

a first substrate having display control circuitry formed thereon and a pair of electrodes for each display pixel, the pair of electrodes operative in a display updating function and in a touch sensing function and arranged in an in-plane-switching arrangement;

a second substrate adjacent the first substrate;

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

one or more transistors disposed on the first substrate for switching between the display updating function and the touch sensing function,

one or more gate lines exclusively for controlling the one or more transistors;

in the display updating function, for each pair of electrodes, a first electrode of the pair of electrodes serving as a common electrode and receiving a common voltage modulation signal, and a second electrode of the pair of electrodes coupled to receive LCD display data over a display data line; and

in a touch sensing function, for each pair of electrodes, at least the first electrode of the pair of electrodes receiving a touch stimulation signal over a touch drive line, and at least the second electrode of the pair of electrodes coupled to a capacitance measuring circuit over a touch sense line; and

wherein, for each pixel, the display data line, used for display data in the display updating function, is used as the touch sense line in the touch sensing function.

25. The touch screen of claim 24, wherein the capacitance measuring circuitry comprises a charge amplifier.

26. The touch screen of claim 24, wherein the touch stimulation signal has a periodic waveform of high frequency such that it does not negatively affect the display state of the liquid crystal layer.

27. An electronic device incorporating the touch screen as recited in claim 24.

28. The touch screen of claim 24, wherein the display is oriented with the second substrate positioned nearer a user than the first substrate.

29. The touch screen of claim 24, wherein the display is oriented with the first substrate positioned nearer a user than the second substrate.

30. The touch screen of claim 24, further comprising:

for each pair of electrodes;

a first and second capacitor connected in series and connected to the first of the pair of electrodes at a junction of the first and second capacitors;

the first capacitor coupled to receive the common voltage modulation signal during the display updating function and the touch stimulation signal during the touch sensing function.

31. The touch screen of claim 30, wherein the first capacitor has a first and second plate and the first plate of the first capacitor is coupled to receive the common voltage modulation signal during the display updating function and the touch stimulation signal during the touch sensing function and the second plate is coupled to the junction of the first and second capacitors, and wherein the touch screen further comprises:

a first transistor, constituting the one or more transistors, and connected to the first plate of the first capacitor and to the first electrode and rendered conductive by a gate signal to a gate thereof from the one or more gate lines during the display updating function to couple the common voltage modulation signal to the first electrode, the first transistor rendered non-conductive during the touch sensing function.

32. The touch screen of claim 31, further comprising:

for each pair of electrodes;

a third and fourth capacitor connected in series and connected to the second of the pair of electrodes at the junction of the third and fourth capacitors, the third capacitor coupled to receive the common voltage modulation signal during the display updating function and the touch stimulation signal during the touch sensing function.

33. The touch screen of claim 32, wherein the third capacitor has a first and second plate and the first plate of the third capacitor is coupled to receive the common voltage modulation signal during the display updating function and the touch stimulation signal during the touch sensing function, and the second plate of the third capacitor is coupled to the junction of the third and fourth capacitors, and wherein the touch screen further comprises:

a second transistor, constituting the one or more transistors, and connected to the second plate of the third capacitor and to the second electrode and rendered conductive by a gate signal to a gate thereof from the one or more gate lines during the display updating function to couple the LCD display data to the second electrode, the second transistor rendered non-conductive during the touch sensing function.