SEGMENTED VCOM

• US 20110187677A1
• Filed: 04/11/2011
• Published: 08/04/2011
• Est. Priority Date: 06/09/2006
• Status: Active Grant

• Current Assignee: Andrew Bert Hodge, Brian Richards Land, Christoph Horst Krah, John Greer Elias, John Z. Zhong, Steve Porter Hotelling, Wei Chen, Wei Hsin Yao, Willem Den Boer
• Original Assignee: Andrew Bert Hodge, Brian Richards Land, Christoph Horst Krah, John Greer Elias, John Z. Zhong, Steve Porter Hotelling, Wei Chen, Wei Hsin Yao, Willem Den Boer
• Inventors: Yao, Wei Hsin, Zhong, John Z., Hotelling, Steve Porter, den Boer, Willem, Krah, Christoph Horst, Chen, Wei, Land, Brian Richards, Hodge, Andrew Bert, Elias, John Greer
• Granted Patent: US 8,451,244 B2
• Time in Patent Office: Days
• US Class Current: 345/174
• CPC Class Codes: G02F 1/13338 Input devices, e.g. touch panels
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• 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 2300/0478 related to liquid crystal pixels
• CPC Class Codes: G09G 3/3648 using an active matrix G09G3/367 - G09G3/3696 take precedence
• CPC Class Codes: Y10T 29/49826 Assembling or joining

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 display comprising:

a liquid crystal display having a plurality of pixel electrodes and a counter electrode;

the counter electrode segmented into a plurality of touch drive electrodes, the counter electrode operating as a Vcom electrode during a display function and operating as the plurality of touch drive electrodes during a touch function;

a plurality of touch sense electrodes spaced apart from the plurality of touch drive electrodes to form capacitive coupling nodes therebetween;

at least one capacitance touch sensing circuit operatively coupled to the plurality of touch sense electrodes during the touch function for measuring a change in capacitance at the capacitive coupling nodes.

2. The touch screen of claim 1, wherein the liquid crystal display has a color filter plate and wherein the plurality of touch sense electrodes are disposed on the color filter plate.

3. The touch screen of claim 1, wherein the plurality of touch drive electrodes comprise patterned ITO and the plurality of touch sense electrodes comprise patterned ITO.

4. The touch screen of claim 2, wherein the liquid crystal display comprises a plurality of rows of display pixels and wherein each of the plurality of touch drive electrodes overlaps plural rows of display pixels.

5. The touch screen of claim 2, wherein the plurality of touch drive electrodes are disposed on the color filter plate.

6. The touch screen of claim 1, wherein the liquid crystal display comprises a plurality of rows of display pixels and wherein each of the plurality of touch drive electrodes overlaps plural rows of display pixels.

7. The touch screen of claim 6, wherein a touch scanning rate is twice a display refresh rate.

8. The touch screen of claim 2, wherein the plurality of touch drive electrodes are disposed on the color filter plate on a side opposite the plurality of touch sense electrodes.

9. The touch screen of claim 2, wherein the liquid crystal display further comprising:

a first polarizer;

a second polarizer;

an active matrix layer disposed on a first substrate, the first substrate disposed between the first and second polarizers;

the color filter plate disposed between the first and second polarizers and spaced apart from the active matrix layer; and

a liquid crystal layer disposed between the first substrate and the color filter plate.

10. The touch screen of claim 9 wherein the liquid crystal display comprises a plurality of rows of display pixels and wherein each of the plurality of touch drive electrodes overlaps plural rows of display pixels.

11. The touch screen of claim 1, wherein a touch scanning rate is twice a display refresh rate.

12. The touch screen of claim 1, wherein a touch scanning rate is equal to a display refresh rate.

13. The touch screen of claim 4, wherein each display pixel includes a storage capacitor and in the display function a common voltage is applied to each storage capacitor of the plural rows of display pixels overlapped by each of the touch drive segments.

14. The touch screen of claim 13, wherein in the display function, the common voltage is also applied to the touch drive segments.

15. The touch screen of claim 14, wherein in the touch function, a stimulation voltage is applied to the touch drive segments.

16. The touch screen of claim 15, wherein in the touch function, the stimulation voltage is also applied to each storage capacitor of the plural rows of display pixels overlapped by a given touch drive segment which receives the stimulation voltage.

17. The touch screen of claim 15, wherein in the touch function, each storage capacitor of the plural rows of display pixels overlapped by a given touch drive segment which receives the stimulation voltage is placed in an open state.

18. The touch screen of claim 1, wherein in the display function, a common voltage is also applied to the touch drive electrodes;

and in the touch function, a stimulation voltage is applied to the touch drive electrodes.

19. The touch screen of claim 1, wherein the liquid crystal display further comprises:

a first polarizer;

a second polarizer;

an active matrix layer disposed on a first substrate, the first substrate disposed between the first and second polarizers;

a color filter plate disposed between the first and second polarizers and spaced apart from the active matrix layer; and

a liquid crystal layer disposed between the first substrate and the color filter plate; and

wherein the plurality of touch drive electrodes and the plurality of touch sense electrodes are disposed on the color filter plate.

20. The touch screen of claim 19, wherein the plurality of touch drive electrodes and the plurality of touch sense electrodes are disposed on opposite sides of the color filter plate.

21. The touch screen of claim 20, wherein the plurality of touch drive electrodes are disposed on a side of the color filter plate facing the liquid crystal layer, and the plurality of touch sense electrodes are disposed on a side of the color filter plate facing the second polarizer.

22. The touch screen of claim any of claim 1, wherein the display and touch functions are performed simultaneously, and an area of the display of the touch screen being updated in the display function does not overlap an area of the display being scanned in the touch function.

23. The touch screen of any of claim 1, wherein the capacitance touch sensing circuit includes a charge amplifier having an inverting input coupled to receive on output from the plurality of touch sense electrodes, a non-inverting input coupled to a reference potential and an output coupled to the inverting input.

24. The touch screen of claim 22, wherein the capacitance touch sensing circuit includes a charge amplifier having an inverting input coupled to receive on output from the plurality of touch sense electrodes, a non-inverting input coupled to a reference potential and an output coupled to the inverting input.

25. An electronic device incorporating the touch screen as recited in claim 1.

26. A method of integrating the functions of a liquid crystal display and a touch screen comprising:

providing a counter electrode segmented into a plurality of touch drive electrodes for operating as a Vcom electrode during a display function and operating as the plurality of touch drive electrodes during a touch function;

providing a plurality of touch sense electrodes spaced apart from the plurality of touch drive electrodes to form capacitive coupling nodes therebetween, the plurality of touch sense electrodes adapted for coupling to capacitance touch sensing circuitry.

27. The method of claim 26, further comprising:

providing the plurality of touch sense electrodes on a color filter plate.

28. The method of claim 27, further comprising:

providing a plurality of rows of display pixels;

disposing each of the plurality of touch drive electrodes in overlapping relationship with a contiguous group of the plurality of rows of the display pixels.