Integrated touch screens

• US 9,146,414 B2
• Filed: 03/23/2015
• Issued: 09/29/2015
• 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:
  US14/666,174
• Publication Number:
  US 20150192815A1
• Time in Patent Office: 190 Days
• US Class Current: 1/1
• 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 comprising:

a TFT layer;

a plurality of display pixels positioned on the TFT layer;

each display pixel comprising a pixel electrode;

one or more common electrodes positioned on the TFT layer;

each pixel electrode operatively coupled to one of the one or more common electrodes to provide a display function in a display mode of operation;

a color filter substrate;

the thin film transistor (TFT) layer 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, each drive line configured from the one or more common electrodes in a touch sensing mode of operation;

a pixel material disposed between the TFT layer and the color filter substrate; and

a plurality of sense lines disposed on a side of the color filter substrate facing the pixel material, 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 of the plurality of drive lines includes display pixels disposed along a first and second, different directions.

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 one or more common electrodes are connected to display circuitry during a display mode of operation of the touch screen.

5. The touch screen of claim 1, wherein electric fields are applied to the pixel material during the display mode of operation, the electric fields being based on voltages applied to the one or more common electrodes.

6. The touch screen of claim 1, 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.

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 of the plurality of sense lines includes a conductive mesh disposed on the color filter substrate.

9. The touch screen of claim 1, wherein the color filter substrate includes a black mask, and the plurality of sense lines are non-transparent conductors disposed behind the black mask so as not to be visible to a user of the touch screen.

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

a color filter layer disposed on a first substrate;

a plurality of drive lines, disposed on a second substrate, the plurality of drive lines carrying, during a touch sensing mode of 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 configured from one or more common electrodes;

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

display circuitry that controls the pixel material, during a display mode of operation, 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 on a side of the first substrate facing the pixel material; 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 display pixels.

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 individual color filters.

13. The touch screen of claim 11, 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 coating 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 having one or more common electrodes, 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;

a plurality of drive lines disposed on the first substrate, each of the plurality of drive lines formed from the one or more common electrodes;

the one or more 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 layer;

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

a plurality of sense lines disposed between the color filter layer and the pixel material.

19. The touch screen of claim 18, wherein the pixel electrodes of the plurality of display pixels and the one or more common electrodes are configured in an in-plane-switching arrangement.

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.

23. The touch screen of claim 18, wherein the pixel electrodes of the plurality of display pixels and the one or more common electrodes are configured in a fringe-field-switching arrangement.