Integrated touch screens

• US 9,025,090 B2
• Filed: 08/11/2014
• Issued: 05/05/2015
• Est. Priority Date: 12/22/2010
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Chang, Shih Chang, Zhong, John Z.
• Primary Examiner(s): Vu, Phu
• Application Number:
  US14/456,831
• Publication Number:
  US 20150022497A1
• Time in Patent Office: 267 Days
• Field of Search: 349/12
• US Class Current: 349/12
• CPC Class Codes: G02F 1/13306 Circuit arrangements or driving methods for the control of single liquid crystal cells G02F1/132, G02F1/133382 take precedence
• CPC Class Codes: G02F 1/133305 Flexible substrates, e.g. plastics, organic film
• CPC Class Codes: G02F 1/13338 Input devices, e.g. touch panels
• CPC Class Codes: G02F 1/133512 Light shielding layers, e.g. black matrix G02F1/136209 takes precedence
• CPC Class Codes: G02F 1/133514 Colour filters
• CPC Class Codes: G02F 1/134336 Matrix
• CPC Class Codes: G02F 1/1368 in which the switching element is a three-electrode device G02F1/136277 takes precedence
• CPC Class Codes: G06F 1/16 Constructional details or arrangements
• CPC Class Codes: G06F 2203/04104 Multi-touch detection in digitiser, i.e. details about the simultaneous detection of a plurality of touching locations, e.g. multiple fingers or pen and finger
• CPC Class Codes: G06F 2203/04108 Touchless 2D- 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 without distance measurement in the Z direction
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/04164 Connections between sensors and controllers, e.g. routing lines between electrodes and connection pads
• 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

Abstract

Integrated touch screens are provided including drive lines formed of grouped-together circuit elements of a thin film transistor layer and sense lines formed between a color filter layer and a material layer that modifies or generates light. The common electrodes (Vcom) in the TFT layer can be grouped together during a touch sensing operation to form drive lines. Sense lines can be formed on an underside of a color filter glass, and a liquid crystal region can be disposed between the color filter glass and the TFT layer. Placing the sense lines on the underside of the color filter glass, i.e., within the display pixel cell, can provide a benefit of allowing the color filter glass to be thinned after the pixel cells have been assembled, for example.

Claims

1. A capacitive touch screen including a plurality of display pixels, the touch screen comprising:

a color filter layer;

a thin film transistor (TFT) substrate including a plurality of drive lines, wherein the drive lines are configured to transmit stimulation signals, the stimulation signals used to stimulate the capacitive touch screen for the purpose of detecting touch input events;

a liquid crystal layer disposed between the TFT substrate and the color filter layer;

each drive line including groups of the plurality of display pixels connected to a transparent continuous layer of conductive material serving as a common electrode for the drive line and the groups of the plurality of display pixels;

a plurality of sense lines disposed between the liquid crystal layer and the color filter layer, wherein the sense lines are configured to receive signals based on the stimulation signals transmitted by the drive lines and wherein the drive lines and the sense lines form a plurality of capacitive sensing nodes.

2. The touch screen of claim 1, wherein each group of the plurality of display pixels forming a drive line includes display pixels disposed along a first and second, different direction.

3. The touch screen of claim 2, wherein during a touch sensing operation, first stimulation signals are applied to a first drive line and second stimulation signals are applied to a second drive line.

4. The touch screen of claim 2, wherein the common electrode of the groups of the plurality of display pixels is connected to display circuitry during a display operation of the touch screen.

5. The touch screen of claim 4, wherein electric fields are applied to the liquid crystal layer during the display operation, the electric fields being based on voltages applied to the common electrode.

6. The touch screen of claim 1, further comprising a common voltage driver positioned on the TFT substrate.

7. The touch screen of claim 1, wherein each sense line includes a plurality of conductive lines disposed on the color filter layer.

8. The touch screen of claim 7, wherein each sense line includes a conductive mesh disposed on the color filter layer.

9. The touch screen of claim 1, wherein the color filter layer includes a black mask, and the sense lines are disposed on the black mask.

10. A capacitive touch screen including a plurality of display pixels, the touch screen comprising:

a color filter layer;

a plurality of drive lines that carry, during a touch sensing operation, stimulation signals that are used to stimulate the touch screen for the purpose of detecting touch and proximity events, each of the plurality of drive lines including a continuous layer of transparent conductive material serving as a common electrode for the drive line;

a pixel material disposed between the plurality of drive lines and the color filter layer;

display circuitry that controls, during a display operation, the pixel material of each display pixel such that a controlled amount of light from each display pixel passes through the color filter layer to form an image;

a plurality of sense lines that receive sense signals based on the stimulation signals, the sense lines being disposed between the pixel material and the color filter layer; and

touch sensing circuitry connected to receive the sense signals from the plurality of sense lines.

11. The touch screen of claim 10, wherein:

the sense lines are disposed on the color filter layer; and

each of the plurality of drive lines includes groups of the plurality of display pixels connected to the continuous layer of transparent conductive material serving as the common electrode for the drive line during the touch sensing operation and also as the common electrode for the groups of the plurality of display pixels during the display operation.

12. The touch screen of claim 11, wherein the color filter layer includes a plurality of individual color filters, and the sense lines include conductive material disposed between the individual color filters.

13. The touch screen of claim 12, wherein the sense lines include non-transparent conductive material.

14. The touch screen of claim 11, wherein the sense lines include transparent conductive material.

15. The touch screen of claim 11, further comprising an organic coat disposed on the sense lines.

16. The touch screen of claim 10, wherein the pixel material includes a light modifying material.

17. The touch screen of claim 10, wherein the pixel material includes a light generating material.

18. A touch screen including a plurality of display pixels, the touch screen comprising:

a first substrate including a plurality display pixels disposed thereon, each display pixel including a pixel electrode and a switching element for connecting a data line to the pixel electrode to display an image on the touch screen during a display mode of operation, and for disconnecting the data line from the pixel electrode during a touch sensing mode of operation;

a plurality of groups of the display pixels, each group including a transparent continuous layer of conductive material serving as a common electrode for the group, the common electrode receiving a common voltage during the display mode of operation and a stimulation voltage during the touch sensing mode of operation;

a second substrate including a color filter;

a pixel material disposed between the first and second substrates; and

a plurality of sense lines disposed between the second substrate and the pixel material.

19. The touch screen of claim 18, wherein the stimulation voltage includes an alternating current waveform.

20. The touch screen of claim 19, wherein the display pixels are arranged along a first direction and along a second direction, perpendicular to the first direction, and wherein a plurality of drive lines is formed by the plurality of groups of display pixels;

and

the sense lines are disposed along the second direction, crossing the drive lines;

wherein each intersection of one of the drive lines with one of the sense lines forms a capacitive sensing node.

21. The touch screen of claim 18, wherein the pixel material includes a light modifying material.

22. The touch screen of claim 18, wherein the pixel material includes a light generating material.