DISPLAY WITH DUAL-FUNCTION CAPACITIVE ELEMENTS

• US 20100001973A1
• Filed: 09/29/2008
• Published: 01/07/2010
• Est. Priority Date: 07/03/2008
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Huang, Lili, Zhong, John Z., Hotelling, Steve Porter, Chang, Shih Chang
• Granted Patent: US 8,508,495 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: G02F 1/133388 with constructional differences between the display region and the peripheral region
• 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 1/13606 having means for reducing parasitic capacitance
• CPC Class Codes: G02F 1/136213 Storage capacitors associated with the pixel electrode
• CPC Class Codes: G02F 1/136218 Shield electrodes
• CPC Class Codes: G02F 1/136286 Wiring, e.g. gate line, drain line
• CPC Class Codes: G02F 1/1393 the birefringence of the liquid crystal being electrically controlled, e.g. ECB-, DAP-, HAN-, PI-LC cells G02F1/1396, G02F1/141 take precedence
• CPC Class Codes: G02F 2201/40 Arrangements for improving the aperture ratio
• CPC Class Codes: G06F 2203/04101 2.5D-digitiser, i.e. digitiser detecting the X/Y position of the input means, finger or stylus, also when it does not touch, but is proximate to the digitiser's interaction surface and also measures the distance of the input means within a short range in the Z direction, possibly with a separate measurement setup
• CPC Class Codes: G06F 2203/04103 Manufacturing, i.e. details related to manufacturing processes specially suited for touch sensitive devices
• CPC Class Codes: G06F 2203/04107 Shielding in digitiser, i.e. guard or shielding arrangements, mostly for capacitive touchscreens, e.g. driven shields, driven grounds
• 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 2203/04808 Several contacts: gestures triggering a specific function, e.g. scrolling, zooming, right-click, when the user establishes several contacts with the surface simultaneously; e.g. using several fingers or a combination of fingers and pen
• CPC Class Codes: G06F 3/017 Gesture based interaction, e.g. based on a set of recognized hand gestures interaction based on gestures traced on a digitiser G06F3/04883
• 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 3/0445 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 3/36 : using liquid crystals

Abstract

A touch screen including display pixels with capacitive elements is provided. The touch screen includes first common voltage lines connecting capacitive elements in adjacent display pixels, and a second common voltage line connecting first common voltage lines. The pixels can be formed as electrically separated regions by including breaks in the common voltage lines. The regions can include a drive region that is stimulated by stimulation signals, a sense region that receives sense signals corresponding to the stimulation signals. A grounded region can also be included, for example, between a sense region and a drive region. A shield layer can be formed of a substantially high resistance material and disposed to shield a sense region. A black mask line and conductive line under the black mask line can be included, for example, to provide low-resistance paths between a region of pixels and touch circuitry outside the touch screen borders.

Claims

1. A touch screen including display pixels with capacitive elements, the touch screen comprising:

a plurality of first common voltage lines connecting capacitive elements in a plurality of adjacent display pixels; and

a second common voltage line connecting two or more first common voltage lines.

2. The touch screen of claim 1, wherein the capacitive elements operate collectively as at least one of a drive line and a sense line of a touch sensing system.

3. The touch screen of claim 1, wherein at least one of a first common voltage line and a second common voltage line comprises at least two layers of conductive material.

4. The touch screen of claim 3, further comprising:

conductive vias formed between the at least two layers of conductive material.

5. The touch screen of claim 1, wherein the capacitive elements include least one of pixel electrodes and storage electrodes.

6. The touch screen of claim 1 including a plurality of second common voltage lines, wherein a plurality of first common voltage lines and a plurality of second common voltage lines include breaks that electrically separate groups of capacitive elements to form a plurality of regions of pixels, wherein all of the capacitive elements of pixels in a region are electrically connected together.

7. The touch screen of claim 6, further comprising:

touch sensing circuitry that transmits a stimulation signal through a group of capacitive elements.

8. The touch screen of claim 7, wherein a group of capacitive elements form at least one of a sense line and a drive line of a touch sensing system.

9. The touch screen of claim 7, wherein the capacitive elements include at least one of a fringe field electrode, a pixel electrode, and a storage electrode.

10. The touch screen of claim 7, wherein the capacitive elements include upper and lower pixel electrodes.

11. The touch screen of claim 10, wherein the upper and lower pixel electrodes of each pixel are electrically connected such that a relative voltage between the upper and lower pixel electrodes of each pixel remains constant when a modulated stimulation signal is applied by the touch sensing circuitry.

12. The touch screen of claim 7, wherein the touch sensing circuitry includes a charge amplifier.

13. The touch screen of claim 7, wherein one or more regions of pixels are electrically connected to the touch sensing circuitry by one of a first common voltage line and a second common voltage line.

14. The touch screen of claim 6, wherein one or more regions of pixels are shaped as one of a square, rectangle, a sawtooth, a pyramid, an inverted pyramid, and a zig-zag of polygons.

15. The touch screen of claim 1, wherein one or more of the display pixels operates as one of an electrically controlled birefringence (ECB) liquid crystal display (LCD) pixel and an in-plane switching (IPS) LCD pixel.

16. The touch screen of claim 1, wherein a first conductive layer includes a portion of a first common voltage line and a portion of a second common voltage line.

17. The touch screen of claim 1, wherein at least one of a first common voltage line and a second common voltage line is formed in a same layer as a capacitive element.

18. The touch screen of claim 1, wherein one or more display pixels that do not include a first common voltage line are disposed between two display pixels that include first common voltage lines.

19. The touch screen of claim 1, wherein one or more display pixels that do not include a second common voltage line are disposed between two display pixels that include second common voltage lines.

20. The touch screen of claim 6, further comprising:

a grounded section between two regions of pixels.

21. The touch screen of claim 20, wherein the grounded section is positioned in between a drive region of pixels that is stimulated by stimulation signals and a sense region of pixels that receives sense signals corresponding to the stimulation signals.

22. The touch screen of claim 6, further comprising:

a shield layer formed of a substantially high resistance material positioned between a surface of the touch screen and a sense region of pixels that receives sense signals.

23. The touch screen of claim 22, wherein the shield layer is formed of a high resistance organic material.

24. The touch screen of claim 6, further comprising:

a black mask line.

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

a conductive line under the black mask line.

26. The touch screen of claim 25, wherein the conductive line is connected to a region of pixels.

27. The touch screen of claim 6, wherein a region of pixels is operated during a first period of time as a drive region of pixels that is stimulated by stimulation signals and is operated during a second period of time as a sense region of pixels that receives sense signals corresponding to the stimulation signals.

28. The touch screen of claim 1, the touch screen formed within a computing system.

29. A touch screen including display pixels with capacitive elements, the touch screen comprising:

a plurality regions of display pixels, the capacitive elements of each region (i) being electrically connected together with a grid of first common voltage lines and second common voltage lines and (ii) being electrically separated from other regions by breaks in the grid.

49. The method of claim 29, wherein forming a plurality of first common voltage lines comprises:

forming a first layer of conductive material including the first common voltage lines.

50. The method of claim 29, wherein forming a second common voltage line comprises:

forming lower portions of the second common voltage line that connects together the first common voltage lines;

forming a passivation layer;

forming vias in the passivation layer; and

forming a second layer of conductive material including upper portions of the second common voltage line, wherein the upper portions are connected to the vias to form the second common voltage line.

51. The method of claim 29, wherein the capacitive elements include least one of pixel electrodes and storage electrodes.

52. The method of claim 29, wherein a plurality of second common voltage lines are formed, the method further comprising:

forming a plurality of first common voltage lines and a plurality of second common voltage lines to include breaks that electrically separate groups of capacitive elements to form a plurality of regions of pixels, wherein all of the capacitive elements of pixels in a region are electrically connected together.

53. The method of claim 52, further comprising:

forming touch sensing circuitry that transmits a stimulation signal through a group of capacitive elements.

54. The method of claim 53, wherein group of capacitive elements form at least one of a sense line and a drive line of a touch sensing system.

55. The touch screen of claim 54, wherein one or more regions of pixels are electrically connected to the touch sensing circuitry by one of a first common voltage line and a second common voltage line.

56. The method of claim 52, wherein the capacitive elements are formed as at least one of a fringe field electrode, a pixel electrode, and a storage electrode.

57. The method of claim 52, wherein one or more regions of pixels are formed in the shaped of one of a square, rectangle, a sawtooth, a pyramid, an inverted pyramid, and a zig-zag of polygons.

58. The method of claim 29, wherein at least one of a first common voltage line and a second common voltage line is formed in a same layer as a capacitive element.

30. A touch screen including display pixels with capacitive elements, the touch screen comprising:

a drive region of display pixels that is stimulated by stimulation signals;

a sense region of display pixels that receives sense signals corresponding to the stimulation signals; and

a grounded region of display pixels that is grounded, wherein the capacitive elements of each region (i) are electrically connected together by first common voltage lines and second common voltage lines and (ii) are electrically separated from other regions by breaks in the grid.

31. The touch screen of claim 30, wherein the grounded region is disposed in between the sense region and the drive region.

32. A touch screen including display pixels with capacitive elements, the touch screen comprising:

a drive region of display pixels disposed on a first side of a surface of the touch screen and including capacitive elements that emanate an electric field to a second side of the surface;

a sense region of display pixels disposed on the first side of the surface and including capacitive elements that receive the electric field from the second side of the surface; and

a shield layer formed of a substantially high resistance material disposed such that the electric field from the second side of the surface passes through the shield layer before being received by the sense region.

33. The touch screen of claim 32, wherein the shield layer is formed of a high resistance organic material.

34. The touch screen of claim 33, wherein the high resistance organic material is carbon nanotubes.

35. A touch screen including display pixels with capacitive elements, the touch screen comprising:

a drive region of display pixels that is stimulated by stimulation signals;

a sense region of display pixels that receives sense signals corresponding to the stimulation signals;

a black mask line; and

a conductive line under the black mask line.

36. The touch screen of claim 35, wherein the conductive line is connected to one of the drive region and the sense region.

37. A mobile telephone including a touch screen comprising:

a plurality of first common voltage lines connecting capacitive elements in a plurality of adjacent display pixels; and

a second common voltage line connecting two or more first common voltage lines.

38. A digital media player including a touch screen comprising:

a plurality of first common voltage lines connecting capacitive elements in a plurality of adjacent display pixels; and

a second common voltage line connecting two or more first common voltage lines.

39. A method of operating a touch screen including pixels with capacitive elements comprising:

operating the capacitive elements during a display phase to produce an image on the touch screen;

operating the capacitive elements during a touch phase to sense a touch event on or near the touch screen, wherein the touch phase includes at least one of transmitting a stimulation signal to the capacitive elements and receiving a sense signal from the capacitive elements.

40. The method of claim 39, wherein operating the capacitive elements during the touch phase comprises:

driving capacitive elements in a drive region of pixels with a stimulation signal; and

sensing electric fields produced by the drive region with capacitive elements in a sense region of pixels.

41. The method of claim 39, wherein the display phase and the touch phase alternate periodically.

42. The method of claim 39, wherein operating the capacitive elements during the touch phase comprises:

transmitting an alternating current (AC) signal through capacitive elements in the drive region, the AC signal having a same direct current (DC) offset as an LCD inversion signal transmitted through the capacitive elements during the display phase.

43. The method of claim 39, wherein the frequency of the stimulation signal is substantially greater than a response time of liquid crystal in pixels of the drive regions.

44. The method of claim 39, wherein operating the capacitive elements during the display phase comprises:

transmitting an inversion signal through a common line connecting drive regions to perform LCD inversion of liquid crystal in pixels of the drive regions.

45. The method of claim 44, wherein the LCD inversion signal is a square wave signal.

46. The method of claim 39, further comprising:

determining a location of a touch event sensed by a sense region based a misalignment of the sense region in a predetermined direction.

47. The method of claim 39, wherein a region of pixels is operated as a drive region during a first period of time and is operated as a sense region during a second period of time.

48. A method of manufacturing a touch screen, the method comprising:

forming a plurality of first common voltage lines connecting capacitive elements in a plurality of adjacent display pixels; and

forming a second common voltage line connecting two or more first common voltage lines.