Multi-touch active display keyboard

1. A touch sensitive display device comprising:

a display fabricated on a first flexible substrate having a thickness of d 2 , the display having a viewing surface, a display medium and a second flexible substrate between the display medium and the viewing surface, the second flexible substrate having a thickness of d 1 ; and

a plurality of resistive touch sensitive elements under the display, each of the plurality of resistive touch sensitive elements is discrete from each of the other resistive touch sensitive elements, the resistive touch sensitive elements being operable by touching the viewing surface of the display, and each of the plurality of resistive touch sensitive elements having an output for outputting a signal responsive to the viewing surface being touched,

wherein each of the plurality of resistive touch sensitive elements defines a non-overlapping region of the viewing surface in which the resistive touch sensitive element produces an output in response to a touch, wherein the plurality of resistive touch sensitive elements are arranged such that two or more simultaneous touches of different regions of the viewing surface produces output signals corresponding to the two or more touches of the viewing surface,

wherein each of said resistive touch sensitive elements comprises its own separate upper sensor substrate having a thickness of d 3 and its own separate lower sensor substrate having a thickness of d 4 and each of the upper and lower sensor substrates is flexible;

wherein the thickness of each lower sensor substrate d 4 is defined as: d 4 >d 1 +d 2 +d 3 ;

wherein said resistive touch sensitive elements are in a neutral axis of the touch sensitive display device;

wherein each of the resistive touch sensitive elements comprises its own separate upper conducting layer on said separate upper sensor substrate and its own separate lower conducting layer on said separate lower sensor substrate; and

wherein each of the separate upper conducting layers are mutually electrically isolated from one another and each of the separate lower conducting layers are mutually electrically isolated from one another.

2. The device of claim 1 , wherein the first flexible substrate comprises polyethyleneterephtalate (PET) or polyethyleneaphtalene (PEN).

3. The device according to claim 1 , wherein the display comprises a display backplane.

4. The device of claim 3 , wherein the display backplane comprises an active matrix of thin-film transistors.

5. The device of claim 3 , wherein the device includes a plurality of interconnections for connecting components of the device to one another.

6. The device according to claim 1 configured as a keyboard, and wherein the regions define keys of the keyboard.

7. The device according to claim 6 , wherein one or more of the regions define one or more of a shift, control, alt, caps, num, function or operation key.

8. The device according to claim 6 , wherein one or more of the regions define a QWERTY keyboard.

9. The device as claimed in claim 6 further comprising a region defining a mouse track-pad.

10. The device according to claim 3 , wherein the display includes an electrophoretic display medium over the display backplane.

11. The device according to claim 1 , wherein the output signals corresponding to the two or more touches of the viewing surface are produced simultaneously.

12. The device according to claim 1 further comprising a touch sensor controller, wherein the output of the plurality of resistive touch sensitive elements is coupled to the controller; and wherein the controller is configured to identify simultaneous touches of the regions and to output a touch signal responsive to the identification.

13. The device according to claim 1 wherein said display includes a multilayer electronic structure adapted to solution deposition.

14. The device of claim 13 wherein said multilayer electronic structure comprises an active matrix backplane of said display.

15. The device of claim 14 , wherein said active matrix comprises an array of field-effect transistors comprising an organic semiconductor.

16. The device of claim 15 , wherein said organic semiconductor is a solution-processed polymer semiconductor.

17. The device of claim 15 , wherein said field-effect transistor comprises an organic gate dielectric.

18. The device of claim 17 , wherein said organic gate dielectric is a solution-processed polymer dielectric.

19. The device of claim 17 , wherein said organic gate dielectric is deposited by chemical vapour deposition.

20. The device of claim 19 , wherein said organic gate dielectric is parylene.

21. The device according to claim 17 , wherein said organic gate dielectric has a thickness between 200 nm and 1 micron.

22. A flexible display device incorporating a touch sensitive keyboard, said device comprising:

a display fabricated on a first flexible substrate having a thickness of d 2 , the display having a viewing surface, a display medium and a second flexible substrate between the display medium and the viewing surface, the second flexible substrate having a thickness of d 1 ; and

a resistive touch sensor behind said display surface;

wherein said resistive touch sensor has at least two non-overlapping regions each with its own upper and lower electrical contacts, the upper electrical contacts of the at least two non-overlapping regions electrically separate from one another and the lower electrical contacts of the at least two non-overlapping regions electrically separate from one another, a first of said regions being configured to define a plurality of user-operable keys, a second of said regions being configured to define at least one user-operable combination key for operation in combination with one of said plurality of keys;

wherein said device has electrical output connections which enable operation of said combination key simultaneously with operation of one of said plurality of keys to be detected,

wherein the upper electrical contact of each region of the resistive touch sensor is on its own separate upper flexible sensor substrate having a thickness of d 3 and the lower electrical contact of each region of the resistive touch sensor is on its own separate lower sensor substrate having a thickness of d 4 ; wherein the thickness of each lower sensor substrate d 4 is defined as: d 4 >d 1 +d 2 +d 3 ; and

wherein said resistive touch sensor is in a neutral axis of the flexible display device.

23. A flexible display device as claimed in claim 22 , wherein said at least one user-operable combination key comprises a plurality of said combination keys.

24. A flexible display device as claimed in claim 23 , wherein a said combination key of said at least one user-operable combination key comprises one of a shift, control, alt, caps, num, function or operation key.

25. A method of producing a touch screen component comprising a display and a plurality of resistive touch screen elements, the method comprising:

fabricating the display on a first flexible substrate, the first flexible substrate having a thickness of d 2 , the display having a viewing surface, a display medium and a second flexible substrate between the display medium and the viewing surface, the second flexible substrate having a thickness of d 1 , each resistive touch screen element comprising its own separate upper sensor substrate having a thickness of d 3 and its own separate lower flexible sensor substrate having a thickness of d 4 ;

mounting the plurality of resistive touch screen elements under the display such that each of the plurality of resistive touch screen elements defines a non-overlapping region of the viewing surface in which each of the resistive touch screen elements produces an output in response to a touch of the viewing surface, and such that two or more simultaneous touches of different regions of the viewing surface produces an output signal from an output of the resistive touch screen elements corresponding to the two or more touches of the viewing surface; and

fabricating each of said resistive touch screen elements on said lower flexible sensor substrate of the resistive touch screen element; wherein the thickness of each lower flexible sensor substrate d 4 is defined as: d 4 >d 1 +d 2 +d 3 ;

wherein said resistive touch screen elements are in a neutral axis of the touch screen component;

wherein each of the resistive touch screen elements comprises its own separate upper conducting layer on said separate upper sensor substrate and its own separate lower conducting layer on said separate lower flexible sensor substrate; and

wherein each of the upper conducting layers are mutually electrically isolated from one another and each of the lower conducting layers are mutually electrically isolated from one another.

26. A method of producing a touch signal responsive to two or more simultaneous touches of two or more regions of a viewing surface of a ouch sensitive display device, wherein the touch sensitive display device comprises:

a display fabricated on a first flexible substrate having a thickness of d 2 , the display having a viewing surface, a display medium and a second flexible substrate between the display medium and the viewing surface, the second flexible substrate having a thickness of d 1 ; and

a plurality of resistive touch sensitive elements under the display, each of the plurality of resistive touch sensitive elements being operable by touching the viewing surface of the display, and each of the plurality of resistive touch sensitive elements having an output for outputting a signal responsive to the viewing surface being touched,

wherein each of the plurality of resistive touch sensitive elements defines a non-overlapping region of the viewing surface in which the resistive touch sensitive element produces an output in response to a touch, and the two or more regions correspond to two or more different regions defined by the resistive touch sensitive elements,

wherein the plurality of resistive touch sensitive elements are arranged such that two or more simultaneous touches of different regions of the viewing surface produces output signals corresponding to the two or more touches of the viewing surface, and

wherein each of said resistive touch sensitive elements comprises its own separate upper sensor substrate having a thickness of d 3 and its own separate lower sensor substrate having a thickness of d 4 and each of the upper and lower sensor substrates is flexible;

wherein the thickness of each lower sensor substrate d 4 is defined as: d 4 >d 1 +d 2 +d 3 ;

wherein said resistive touch sensitive elements are in a neutral axis of the touch sensitive display device;

wherein each of the resistive touch sensitive elements comprises its own separate upper conducting layer on said upper sensor substrate and its own separate lower conducting layer on said lower sensor substrate; and

wherein each of the upper conducting layers are mutually electrically isolated from one another and each of the lower conducting layers are mutually electrically isolated from one another;

the method comprising:

receiving a signal from each of the resistive touch sensitive elements corresponding to the two or more regions being touched;

identifying the two or more regions being touched using the signals from the resistive touch sensitive elements; and

outputting a touch signal responsive to the identification.