Display with dual-function capacitive elements

• US 8,743,087 B2
• Filed: 07/08/2013
• Issued: 06/03/2014
• Est. Priority Date: 07/03/2008
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Hotelling, Steve Porter, Chang, Shih Chang, Huang, Lili, Zhong, John Z.
• Primary Examiner(s): Lubit, Ryan A
• Application Number:
  US13/936,980
• Publication Number:
  US 20130293513A1
• Time in Patent Office: 330 Days
• Field of Search: 345173-178, 178 1801- 2004
• 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 a display region having display pixels and a non-display border region, the touch screen comprising:

a plurality of first common voltage lines disposed in rows including at least one row having a plurality of first portions that are electrically separate in the at least one row in the display region;

a plurality of second common voltage lines disposed in columns including at least one column having a plurality of second portions that are electrically separate in the at least one column in the display region;

a plurality of first and second regions, each region including a plurality of display pixels each having a capacitive element, wherein in each region, the capacitive elements are electrically connected together via one or more portions of each of the first and second common voltage lines, and the plurality of first regions are electrically separated from the plurality of second regions in the display region in a touch sensing mode of operation;

wherein capacitive elements within each region are configured to provide a display function in a display mode of operation of the touch screen and to provide capacitive coupling between at least one region of the plurality of first regions serving as a drive region, and one region of the plurality of second regions serving as a sense region, in the touch sensing mode of operation.

2. The touch screen of claim 1, wherein during the touch sensing mode of operation, the plurality of first regions are electrically connected together in the non-display border region of the touch screen.

3. The touch screen of claim 1, wherein the capacitive elements of each of the plurality of first regions emanate an electric field;

the capacitive elements of each of the plurality of second regions receive the electric field; and

a shield layer formed of a substantially high resistance material disposed such that the electric field passes through the shield layer before being received by the sense regions.

4. The touch screen of claim 3, wherein the drive regions and the sense regions are disposed on a common substrate.

5. The touch screen of claim 4, wherein the touch screen comprises a cover and the drive shield layer is disposed between the cover and the drive and sense regions.

6. The touch screen of claim 5, wherein the plurality of first regions are electrically connected together in a non-display border region of the touch screen.

7. The touch screen as recited in claim 1, wherein the display region includes a liquid crystal display.

8. The touch screen as recited in claim 7, wherein each of the plurality of display pixels includes a fringe field electrode.

9. The touch screen as recited in claim 8, wherein the fringe field electrode is configured to operate in a display mode of operating during the touch sensing mode of operation.

10. A method of operating a touch screen including a display region having display pixels and a non-display border region, the touch screen having a plurality of first common voltage lines disposed in rows including at least one row having a plurality of first portions that are electrically separate in the at least one row in the display region;

a plurality of second common voltage lines disposed in columns including at least one column having a plurality of second portions that are electrically separate in the at least one column in the display region;

a plurality of first and second regions, each region including a plurality of display pixels each having a capacitive element, wherein in each region, the capacitive elements are electrically connected together via one or more portions of each of the first and second common voltage lines, and the plurality of first regions are electrically separated from the plurality of second regions in the display region in a touch sensing mode of operation;

wherein capacitive elements within each region are configured to provide a display function in a display mode of operation of the touch screen and to provide capacitive coupling between at least one region of the plurality of first regions serving as a drive region, and one region of the plurality of second regions serving as a sense region in the touch sensing mode of operation;

the method comprising;

operating the capacitive elements during the display mode of operation to produce an image on the touch screen;

operating the capacitive elements during the touch sensing mode of operation to sense a touch event on or near the touch screen, wherein operating the capacitive elements during the touch sensing mode of operation comprises;

driving the capacitive elements in the plurality of first regions of display pixels with a stimulation signal; and

sensing electric fields with the capacitive elements in at least one of the plurality of second regions of display pixels, and wherein the display mode of operation and the touch sensing mode of operation alternate periodically.

11. The method of claim 10 wherein operating the capacitive elements during the touch sensing mode of operation comprises:

transmitting an alternating current (AC) signal through capacitive elements in the plurality of first regions , the AC signal having a same direct current (DC) offset as an LCD inversion signal transmitted through the capacitive elements during the display mode of operation.

12. A stackup of a touch screen including a display region having display pixels and a non-display border region, the stackup comprising:

a plurality of gate lines;

a plurality of data lines;

the plurality of gate lines and the plurality of data lines coupled to the plurality of pixels for enabling display of data by the plurality of pixels;

a plurality of first common voltage lines disposed in rows including at least one row having a plurality of first portions that are electrically separate in the at least one row in the display region;

a plurality of second common voltage lines disposed in columns including at least one column having a plurality of second portions that are electrically separate in the at least one column in the display region;

a plurality of first and second regions, each region including a plurality of display pixels each having a capacitive element, wherein in each region, the capacitive elements are electrically connected together via one or more portions of each of the first and second common voltage lines, and the plurality of first regions are electrically separated from the plurality of second regions in the display region in a touch sensing mode of operation, wherein the first regions are drive regions and the second regions are sense regions;

at least one bus line forming part of an electrical connection that connects together the plurality of first regions in the touch sensing mode of operation; and

wherein the at least one bus line is disposed in the non-display border region of the display screen.

13. The stackup of claim 12, wherein the plurality of first common voltage lines are formed from a single layer of conductive material.

14. The stackup of claim 13 wherein the plurality of second common voltage lines are formed of another single layer of conductive material.

15. The stackup of claim 12, wherein the circuit elements are storage capacitors of the display pixels.

16. The stackup of claim 12, wherein the at least one bus line comprises first bus lines that connect together the plurality of first regions in the touch sensing mode of operation and at least an additional bus line that connects together the plurality of second regions in the touch sensing mode of operation a third region of display pixels, wherein circuit elements of the display pixels of the third region are electrically connected together in.

17. A touch sensing system comprising:

a stackup of a touch screen including a display region having display pixels and a non-display border region comprising;

a plurality of gate lines;

a plurality of data lines;

a plurality of first common voltage lines disposed in rows including at least one row having a plurality of first portions that are electrically separate in the at least one row in the display region;

a plurality of second common voltage lines disposed in columns including at least one column having a plurality of second portions that are electrically separate in the at least one column in the display region;

a plurality of first and second regions, each region including a plurality of display pixels each having a capacitive element, wherein in each region, the capacitive elements are electrically connected together via one or more portions of each of the first and second common voltage lines, and the plurality of first regions are electrically separated from the plurality of second regions in the display region in a touch sensing mode of operation;

wherein capacitive elements within each region are configured to provide a display function in a display mode of operation of the touch screen and to provide capacitive coupling between at least one region of the plurality of first regions serving as a drive region, and one region of the plurality of second regions serving as a sense region in the touch sensing mode of operation;

a drive circuit configured to provide stimulation signals to the plurality of first regions during the touch mode of operation; and

a sense channel connected to the plurality of second regions during the touch sensing mode of operation.

18. The touch sensing system of claim 17, further comprising:

at least one bus line forming part of an electrical connection that connects together the plurality of first regions in the touch sensing mode of operation; and

wherein the at least one bus line is disposed in the non-display border region of the display screen.

19. The touch sensing system of claim 17, wherein the capacitive elements of the plurality of first and second regions are common electrodes.

20. The touch sensing system of claim 17, wherein the capacitive elements of the plurality of first and second regions are fringe field electrodes.