TOUCH SCREEN LIQUID CRYSTAL DISPLAY

• US 20080062140A1
• 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: Yao, Wei, Hotelling, Steve, Chen, Wei, Den Boer, Willem, Krah, Christoph, Hodge, Andrew, Zhong, John, Elias, John, Land, Brian
• Granted Patent: US 8,654,083 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: 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 circuitry comprising a pair of electrodes for each display sub-pixel;

a second substrate adjacent the first substrate;

at least one touch sensing element disposed between the first and second substrates wherein all touch sensing elements are disposed between the first and second substrates.

2. The touch screen of claim 1 wherein the at least one touch sensing element between the first and second substrates comprises:

a touch drive electrode, wherein the touch drive electrode is one of the pair of electrodes for a display sub-pixel;

a touch sense electrode, wherein the touch sense electrode is one of the pair of electrodes for each display sub-pixel; and

one or more switches adapted to switch the electrodes between a display function and a touch function.

3. The touch screen of claim 2 wherein the one or more switches comprise TFTs.

4. The touch screen of claim 2 wherein V_COM is used as a source of a touch drive signal.

5. The touch screen of claim 2 wherein a display data line is used as a touch sense line.

6. The touch screen of claim 2 wherein the at least one touch sensing element between the first and second substrates further comprises a plurality of metal sense lines disposed on the first substrate.

7. The touch screen of claim 2 wherein the second substrate is positioned nearer a user than the first substrate.

8. The touch screen of claim 2 wherein the first substrate is positioned nearer a user than the second substrate.

9. The touch screen of claim 1 wherein a first plurality of display sub-pixels are connected to form a plurality of touch sense rows and a second plurality of display sub-pixels are connected to form a plurality of touch sense columns.

10. An electronic device incorporating an 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 sub-pixel;

a second substrate adjacent the first substrate;

at least one touch sensing element disposed between the first and second substrates wherein all touch sensing elements are disposed between the first and second substrates.

11. The electronic device of claim 10 wherein the electronic device is selected from the group consisting of a desktop computer, a tablet computer, and a notebook computer.

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

13. The electronic device of claim 10 wherein the at least one touch sensing element between the first and second substrates comprises:

a touch drive electrode, wherein the touch drive electrode is one of the pair of electrodes for a display sub-pixel;

a touch sense electrode, wherein the touch sense electrode is one of the pair of electrodes for each display sub-pixel; and

one or more switches adapted to switch the electrodes between a display function and a touch function.

14. The electronic device of claim 13 wherein the electronic device is selected from the group consisting of a desktop computer, a tablet computer, and a notebook computer.

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

16. The electronic device of claim 13 wherein V_COM is used as a source of a touch drive signal.

17. The electronic device of claim 16 wherein the electronic device is selected from the group consisting of a desktop computer, a tablet computer, and a notebook computer.

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

19. The electronic device of claim 13 wherein a display data line is used as a touch sense line.

20. The electronic device of claim 19 wherein the electronic device is selected from the group consisting of a desktop computer, a tablet computer, and a notebook computer.

21. The electronic device of claim 19 wherein the electronic device comprises at least one of a handheld computer, a personal digital assistant, a media player, and a mobile telephone.

22. The electronic device of claim 13 wherein the at least one touch sensing element between the first and second substrates further comprises a plurality of metal sense lines disposed on the first substrate.

23. The electronic device of claim 22 wherein the electronic device is selected from the group consisting of a desktop computer, a tablet computer, and a notebook computer.

24. The electronic device of claim 22 wherein the electronic device comprises at least one of a handheld computer, a personal digital assistant, a media player, and a mobile telephone.

25. The electronic device of claim 10 wherein a first plurality of display sub-pixels are connected to form a plurality of touch sense rows and a second plurality of display sub-pixels are connected to form a plurality of touch sense columns.

26. The electronic device of claim 25 wherein the electronic device is selected from the group consisting of a desktop computer, a tablet computer, and a notebook computer.

27. The electronic device of claim 25 wherein the electronic device comprises at least one of a handheld computer, a personal digital assistant, a media player, and a mobile telephone.

28. A mobile telephone incorporating an 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 sub-pixel;

a second substrate adjacent the first substrate;

at least one touch sensing element disposed between the first and second substrates wherein all touch sensing elements are disposed between the first and second substrates.

29. The mobile telephone of claim 28 wherein the at least one touch sensing element between the first and second substrates comprises:

a touch drive electrode, wherein the touch drive electrode is one of the pair of electrodes for a display sub-pixel;

a touch sense electrode, wherein the touch sense electrode is one of the pair of electrodes for each display sub-pixel; and

one or more switches adapted to switch the electrodes between a display function and a touch function.

30. The mobile telephone of claim 29 wherein V_COM is used as a source of a touch drive signal.

31. The mobile telephone of claim 29 wherein a display data line is used as a touch sense line.

32. The mobile telephone of claim 29 wherein the at least one touch sensing element between the first and second substrates further comprises a plurality of metal sense lines disposed on the first substrate.

33. The mobile telephone of claim 28 wherein a first plurality of display sub-pixels are connected to form a plurality of touch sense rows and a second plurality of display sub-pixels are connected to form a plurality of touch sense columns.

34. A method of operating a touch screen comprising an in-plane-switching liquid crystal display with integral touch sensing, wherein the display comprises a first plurality of display pixels connected to form a plurality of touch sense rows and a second plurality of display sub-pixels connected to form a plurality of touch sense columns, the method comprising:

holding the touch sense rows and columns at ground during a first time period;

updating the display during the first time period;

stimulating the touch sense rows during a second time period;

sensing touch at the touch columns during the second time period;

stimulating the touch sense columns during a third time period; and

sensing touch at the touch rows during the third time period.