DISPLAY WITH DUAL-FUNCTION CAPACITIVE ELEMENTS

• US 20130293513A1
• Filed: 07/08/2013
• Published: 11/07/2013
• 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.
• Granted Patent: US 8,743,087 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 first and second regions of display pixels, the capacitive elements of each region being electrically connected together with first voltage lines and second voltage lines and the plurality of first regions being electrically separated from the plurality of second regions;

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 one region of the first plurality of regions and one region of the second plurality of regions.

2. The touch screen of claim 1, wherein the plurality of first regions are electrically connected together in a border region of the touch screen.

3. The touch screen of claim 1, wherein the plurality of first regions comprises drive regions and including capacitive elements that emanate an electric field;

the plurality of second regions comprise sense regions and including capacitive elements that 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 border region of the touch screen.

7. A method of operating a touch screen as recited in claim 1, 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 capacitive elements in the plurality of first regions of display pixels with a stimulation signal; and

sensing electric fields with 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.

8. 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 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.

9. The method of operating a touch screen as recited in claim 6, 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 capacitive elements in the plurality of first regions of display pixels with a stimulation signal; and

sensing electric fields with 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.

10. A stackup of a plurality of display pixels, 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;

at least a first and a second region;

first line portions electrically connecting together in the first direction circuit elements of the display pixels in the first region ;

second line portions electrically connecting together in a second direction the circuit elements of the display pixels in the first region;

third line portions electrically connecting together in the first direction circuit elements of the display pixels in the second region;

fourth line portions electrically connecting together in a second direction the circuit elements of the display pixels in the second region;

at least one bus line forming part of an electrical connection that connects together at least one of the first or second line portions with at least one of the third and fourth line portions; and

wherein the at least one bus line is disposed in a border region of the display panel.

11. The stackup of claim 10, wherein the first and third line portions are formed from a single layer of conductive material.

12. The stackup of claim 11 wherein the second and fourth line portions are formed of another single layer of conductive material.

13. The stackup of claim 10, wherein the circuit elements are storage capacitors of the display pixels.

14. The stackup of claim 10, further comprising:

a third region of display pixels, wherein circuit elements of the display pixels of the third region are electrically connected together in at least one of the first and second directions by fifth line portions.

15. The stackup of claim 14 wherein the third region is disposed between the first and second regions along the first direction.

16. The stackup of claim 15, further comprising a fourth region of display pixels and a fifth region of display pixels, wherein

the first through fifth regions are disposed along the first direction in the order of the first region, the third region, the second region, the fourth region and the fifth region;

the at least one bus line includes a first bus line forming part of an electrical connection that connects together the circuit elements of the first, second and fifth regions, and a second bus line that forms part of an electrical connection that connects together circuit elements of the third and fourth regions.

17. A touch sensing system comprising:

a stackup comprising;

a plurality of gate lines;

a plurality of data lines;

a first, second and third regions of display pixels, the third region disposed between the first and second regions along a first direction;

the plurality of gate lines and the plurality of data lines coupled to the plurality of pixels in the first, second and third regions for enabling display of data by the plurality of pixels in a display mode of operation;

first conductive lines connecting together circuit elements of the display pixels in the first region along the first direction and along a second direction, transverse to the first direction;

second second conductive lines connecting together circuit elements of the display pixels in the second region along the first direction and along the second direction;

third conductive lines connecting together circuit elements of the display pixels in the third region along the first direction and along the second direction;

capacitive elements within the first, second and third regions operative to provide a capacitive coupling between the first and second regions and between the

second and third regions in a touch mode of operation;

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

a sense channel connected to the third region.

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

at least one bus line forming at least a part of an electric connection that connects together the circuit elements of the first and second display pixel, the at least one bus line disposed on a border region of the display pixels.

19. The touch sensing system of claim 18, wherein the first, second and third conductive lines are common voltage lines.

20. The touch sensing system of claim 19, wherein the circuit elements of the first, second and third regions are common electrodes.

21. The touch sensing system of claim 19, wherein the circuit elements of the first, second and third regions are fringe field electrodes.

22. An integrated liquid crystal display touch screen comprising:

a first layer of conductive material including gate lines;

a second layer of conductive material including data lines;

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

the 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 voltage lines connecting together the circuit elements 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 voltage lines, electrically isolated from the first plurality of voltage lines, connecting together the circuit elements 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 voltage lines receiving a stimulating voltage waveform during a touch sensing mode of operation; and

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

23. The integrated liquid crystal display touch screen of claim 22, wherein each of the plurality of display pixels includes a fringe field electrode.

24. The integrated liquid crystal display touch screen of claim 23, wherein the fringe field electrode and the simulating voltage waveform are configured to permit the fringe field electrode operate in a display mode of operating during the touch sensing mode of operation.

25. A touch screen including display pixels with capacitive elements, 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 in between the at least one sense region and the at least one drive region, and wherein capacitive elements of each region (i) are electrically connected together by a grid of first voltage lines and second voltage lines and (ii) the at least one drive region is electrically separated from the at least one sense region;

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 the at least one drive region and the at least one sense region in a touch sensing mode of operation of the touch screen.

26. The touch screen of claim 25, wherein the at least one drive region comprises a plurality of drive regions electrically connected to one another by electrical connections at least partially disposed on a border region of the touch screen.