DISPLAY INTEGRATED PRESSURE SENSOR

• US 20140247239A1
• Filed: 03/04/2013
• Published: 09/04/2014
• Est. Priority Date: 03/04/2013
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: JAMSHIDI-ROUDBARI, Abbas, Chang, Shih Chang, Yu, Cheng-Ho, Chang, Ting-Kuo
• Granted Patent: US 10,402,000 B2
• Time in Patent Office: Days
• US Class Current: 345/174
• CPC Class Codes: G06F 2203/04103 Manufacturing, i.e. details related to manufacturing processes specially suited for touch sensitive devices
• CPC Class Codes: G06F 2203/04105 Pressure sensors for measuring the pressure or force exerted on the touch surface without providing the touch position
• 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 3/0447 Position sensing using the local deformation of sensor cells

Abstract

A touch sensitive device that can detect the amount of pressure being applied to a touch screen from a user or other external object is provided. A spacer of the touch screen can be coated with a layer of conductive material and the change in capacitance between the spacer and various circuit elements of the touch screen can be measured. The change in capacitance can be correlated to the amount of pressure being applied to the touch screen, thus providing a method to determine the pressure being applied. During operation of the device, the system can time multiplex touch, display and pressure sensing operations so as to take advantage of an integrated touch and display architecture.

Claims

1. A display, comprising:

a first layer having a plurality of spacers formed thereon; and

a second layer formed with a separation relative to the first layer, the second layer including a plurality of circuit elements;

wherein the plurality of circuit elements are configurable for coupling with one or more of the spacers in a pressure sensing mode.

2. The display of claim 1, further comprising conductive material formed over the plurality of spacers for coupling with the one or more circuit elements in the pressure sensing mode.

3. The display of claim 1, wherein the plurality of circuit elements are further configurable for operating with the first layer in a display mode.

4. The display of claim 1, wherein the plurality of circuit elements are further configurable for coupling with objects proximate to the display in a touch sensing mode.

5. The display of claim 1, wherein the plurality of circuit elements are further configurable for forming a plurality of row electrodes, column electrodes, and guard shield electrodes.

6. The display of claim 5, wherein one or more of the plurality of row electrodes, column electrodes, and guard shield electrodes are further configurable for generating signals indicative of an amount of pressure in the pressure sensing mode.

7. The display of claim 5, wherein one or more of the spacers are formed over a boundary between a row electrode, a column electrode, or a guard shield electrode.

8. The display of claim 1, wherein the display is a liquid crystal display (LCD), and the plurality of circuit elements include a common electrode layer of the LCD.

9. The display of claim 8, wherein the first layer is a color filter layer, and the spacers are sub-photo spacers formed on the color filter layer.

10. The display of claim 2, wherein the conductive material formed over each spacer is floating.

11. The display of claim 2, wherein the conductive material formed over the plurality of spacers is electrically connected together.

12. The display of claim 11, wherein the conductive material formed over the plurality of spacers is configured for receiving a stimulation signal.

13. A controller, comprising:

a plurality of drivers configured for stimulating one or more drive lines in a stackup;

a plurality of sense channels configured for detecting changes in capacitive coupling in the stackup; and

a processor capable of configuring the plurality of sense channels for detecting object proximity at the stackup in a touch sensing mode, and configuring the plurality of sense channels for detecting object pressure at the stackup in a pressure sensing mode.

14. The controller of claim 13, the processor further capable of configuring the plurality of drivers for stimulating those drive lines at which object proximity has been detected.

15. The controller of claim 13, the processor further capable of configuring the plurality of drivers for stimulating conductive material formed over spacers in the stackup in the pressure sensing mode.

16. The controller of claim 13, the plurality of sense channels configurable for sensing changes in capacitive coupling between one or more spacers in the stackup and one or more of a plurality of rows, plurality of columns, and a plurality of ground shields in the stackup.

17. The controller of claim 16, the processor further capable of determining an amount of object pressure based on the sensed change in capacitive coupling.

18. A method for sensing pressure in a display, comprising:

forming conductive material over a plurality of spacers on a first layer of the display;

detecting changes in capacitive coupling between one or more of the spacers and one or more of a plurality of circuit elements on a second layer of the display; and

determining an amount of object pressure on the display based on the detected changes in capacitive coupling between the spacers and the circuit elements.

19. The method of claim 18, further comprising operating the plurality of circuit elements with the first layer in a display mode.

20. The method of claim 18, further comprising:

detecting changes in capacitive coupling at one or more of the circuit elements; and

determining an amount of object proximity at the display based on based on the detected changes in capacitive coupling at the one or more circuit elements.

21. The method of claim 18, further comprising:

configuring the plurality of circuit elements to form a plurality of row electrodes, column electrodes, and guard shield electrodes; and

generating signals at one or more of the plurality of row electrodes, column electrodes, and guard shield electrodes indicative of an amount of pressure in the pressure sensing mode.

22. The method of claim 18, further comprising forming one or more of the spacers over a boundary between a row electrode, a column electrode, or a guard shield electrode.

23. The method of claim 18, further comprising floating the conductive material formed over each spacer.

24. The method of claim 18, further comprising electrically connecting the conductive material formed over the plurality of spacers.

25. The method of claim 23, further comprising stimulating the conductive material formed over the plurality of spacers with an AC signal.