Display with dual-function capacitive elements

• US 9,354,761 B2
• Filed: 06/12/2015
• Issued: 05/31/2016
• Est. Priority Date: 07/03/2008
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Hotelling, Steven P., Chang, Shih Chang, Huang, Lili, Zhong, John Z.
• Primary Examiner(s): Lubit, Ryan A
• Application Number:
  US14/738,648
• Publication Number:
  US 20150309623A1
• Time in Patent Office: 354 Days
• Field of Search: None
• US Class Current: 1/1
• 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. Groups of 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 portion having display pixels with capacitive elements and a non-display border portion, the touch screen comprising:

a plurality of regions of display pixels positioned in the display portion, the capacitive elements of each region (i) being connected together in the display portion with a grid of common voltage lines extending along first and second directions and (ii) being electrically separated in the display portion from other regions by at least one break in the grid along each of the first and second directions;

wherein capacitive elements within each region are configured to provide a display function in a display mode of operating of the touch screen and to provide capacitive coupling between at least two of the regions in a touch sensing mode of operation of the touch screen.

2. The touch screen of claim 1, wherein at least the plurality of regions comprises drive regions and sense regions of display pixels disposed on a first surface of the touch screen, the capacitive elements of the drive regions emanating an electric field;

capacitive elements of the sense regions receiving the electric field ; and

a shield layer formed of a 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 1, wherein the capacitive elements include a fringe field electrode.

5. The touch screen of claim 1, wherein the capacitive elements include a pixel electrode.

6. The touch screen of claim 1, wherein the capacitive elements include storage electrode.

3. A touch screen including a display portion having display pixels with capacitive elements and a non-display border portion, the touch screen comprising:

at least one drive region of display pixels that is stimulated by stimulation signals;

at least one sense region of display pixels that receives sense signals corresponding to the stimulation signals; and

at least one grounded region of display pixels that is grounded, wherein the at least one ground region is disposed between the at least one sense region and the at least one drive region, and wherein (i) capacitive elements of each region are connected together in the display portion by a grid of common voltage lines and (ii) the at least one drive region electrically is separated in the display portion from the at least one sense region by breaks in the grid;

wherein capacitive elements within the at least one drive region and the at least one sense region are configured to provide a display function in a display mode of operating of the touch screen and to provide capacitive coupling between the at least one drive region and the at least one sense region in a touch sensing mode of operation of the touch screen.

7. A method of operating a touch screen as recited in claim 3, comprising:

operating the capacitive elements in the at least one drive region, the at least one sense region and the at least one ground region 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 capacitive elements in the at least one drive region with a stimulation signal; and

sensing electric fields produced by the at least one drive region with capacitive elements in the at least one sense region.

8. The method of claim 7, further comprising alternately and periodically operating the display and touch sensing modes of operation.

9. The method of claim 7 wherein operating the capacitive elements during the touch sensing mode of operation comprises:

transmitting an alternating current (AC) signal through capacitive elements in the at least one 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 mode of operation.

10. The method of claim 7 wherein a region of pixels is operated as the at least one drive region during a first period of time and is operated as the at least one sense region during a second period of time.

11. A touch sensing system 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 during a display mode of operation;

first conductive lines in a first direction, each of the first conductive lines including a plurality of first line portions extending through plural display pixels and separated from each other in the first direction by disconnections; and

second conductive lines in a second direction transverse to the first direction, each of the second conductive lines including a plurality of second line portions extending through plural display pixels and separated from each other in the second direction by disconnections,

a first region of display pixels serving as a drive region, wherein circuit elements of the display pixels in the first region are electrically connected together in the first direction by a first plurality of the first line portions, and the circuit elements of the display pixels in the first region are electrically connected together in the second direction by a first plurality of the second line portions;

a second region of display pixels serving as a sense region and being disposed on one side of the first region along the first direction, wherein the circuit elements of the display pixels of the second region are electrically connected together in the first and second directions by a second plurality of the first line portions and a second plurality of the second line portions, respectively;

wherein the circuit elements of the display pixels of the second region are disconnected in a display portion during a touch sensing mode of operation from the circuit elements in the first region;

a third region of display pixels serving as another sense region and being disposed on the other side of the first region along the first direction, wherein the circuit elements of the display pixels of the third region are electrically connected together in the first and second directions by a third plurality of the first line portions and a third plurality of the second line portions;

wherein the circuit elements of the display pixels of the third region are disconnected in the display portion during the touch sensing mode of operation from the circuit elements in the first region; and

at least one sense channel connected to the second and third regions;

wherein the circuit elements of the display pixels of the first, second and third regions are configured to provide a display function in the display mode of operating of the touch sensing system and to provide capacitive coupling between the first region and the second region and between the first region and the third regions in the touch sensing mode of operation of the touch sensing system.

12. A touch screen comprising:

a plurality of gate lines;

a plurality of data lines;

a plurality of pixels, each pixel having an pixel electrode and a common electrode;

for each pixel, a capacitor formed by the pixel electrode and the common electrode;

the plurality of gate and data lines coupled to the plurality of pixels for enabling display of data by the plurality of pixels during a display mode of operation;

a first plurality of common voltage lines connecting together the common electrodes of each pixel in a first region along a first and a second direction, the first region serving as a drive region;

a second plurality of common voltage lines, connecting together the common electrodes of each pixel in a second region along the first and the second directions, the second region serving as a sense region;

the first plurality of common voltage lines receiving a stimulating voltage during a touch sensing mode of operation; and

the second plurality of common voltage lines coupled to capacitive measuring circuitry during the touch sensing mode of operation;

wherein during the touch sensing mode of operation, the plurality of first common voltage lines are electrically separated from the plurality of second common voltage lines.