Touch sensitive display utilizing mutual capacitance and self capacitance

• US 9,652,091 B1
• Filed: 03/15/2013
• Issued: 05/16/2017
• Est. Priority Date: 03/15/2013
• Status: Active Grant

• Current Assignee: Amazon Technologies, Inc. (Amazon.com, Inc.)
• Original Assignee: Amazon Technologies, Inc. (Amazon.com, Inc.)
• Inventors: Obeidat, Amjad Turki
• Primary Examiner(s): Spar, Ilana
• Assistant Examiner(s): Truong, Nguyen H
• Application Number:
  US13/838,299
• Time in Patent Office: 1,523 Days
• Field of Search: 345156-184
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/0416 Control or interface arrangements specially adapted for digitisers
• CPC Class Codes: G06F 3/041662 using alternate mutual and self-capacitive scanning
• 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

Systems and methods are provided for detecting gestures using both mutual capacitance and self capacitance touch sensing. These systems may be incorporated into devices utilizing an in-cell touch system, where the display controller is also used to drive the transmitter lines for mutual capacitance scans. The receiver lines can be used in conjunction with the transmitter lines for mutual capacitance sensing, or can be used alone for self capacitance sensing, even when the display controller is not operating, such as when the display is turned off. One-dimensional touch detection using the receiver lines alone can be used to generate different types of gesture inputs or to trigger body proximity sensing.

Claims

1. A touch sensitive computing device, comprising:

a liquid crystal display panel comprising a thin film transistor (TFT) layer, a color filter layer, and a liquid crystal layer positioned between the TFT layer and the color filter layer;

a plurality of electrically conductive transmitter lines positioned on the TFT layer and extending in a first direction;

a plurality of electrically conductive receiver lines positioned on the color filter and extending in a second direction different from the first direction;

a display controller comprising a transmitter circuit operably coupled to the transmitter lines, said display controller configured to drive the transmitter lines to control the liquid crystal layer;

a touch controller comprising receiver circuit operably coupled to the receiver lines and operably coupled to the display controller, said touch controller configured to;

when displaying an image on the liquid crystal display panel, operate in a mutual capacitance mode by instructing the display controller to drive the transmitter lines for mutual capacitance measurements, detecting in the receiver lines mutual capacitance changes between the receiver lines and the transmitter lines, and generating two-dimensional touch location information based on the detected mutual capacitance changes in the receiver lines; and

when no image is displayed on the liquid crystal display panel, operate in a self capacitance mode by detecting self capacitance changes in the receiver lines and generating one-dimensional touch location information based on the self capacitance changes detected in the receiver lines, wherein the touch controller does not generate two-dimensional touch location information in the self capacitance mode; and

at least one processor programmed to respond to the one-dimensional touch location information generated by the touch controller in the self capacitance mode.

2. The touch sensitive computing device of claim 1 wherein said touch controller is configured to operate in the mutual capacitance mode when the computing device is displaying an image with the liquid crystal display panel and is configured to operate in the self capacitance mode when the computing device is not displaying an image with the liquid crystal display panel.

3. The touch sensitive computing device of claim 1 wherein said touch controller is configured to operate in the self capacitance mode when the display controller is not driving the transmitter lines.

4. A computing device, comprising:

a liquid crystal display panel;

a first plurality of electrodes;

a second plurality of electrodes;

a display controller comprising a transmitter circuit operably coupled to the first plurality of electrodes, said display controller configured to drive the first plurality of electrodes; and

a touch controller comprising a receiver circuit operably coupled to the second plurality of electrodes and to the display controller, said touch controller configured to;

when displaying an image on the liquid crystal display panel, operate in a mutual capacitance mode by instructing the display controller to drive the first plurality of electrodes for mutual capacitance measurements, detecting in the second plurality of electrodes mutual capacitance changes between the first and second plurality of electrodes, and generating touch location information based on the detected mutual capacitance changes between the first and second plurality of electrodes; and

when no image is displayed on the liquid crystal display panel, operate in a self capacitance mode by detecting self capacitance changes in the second plurality of electrodes and generating one-dimensional touch location information based on the self capacitance changes detected in the second plurality of electrodes, wherein the touch controller does not generate two-dimensional touch location information in the self capacitance mode; and

at least one processor programmed to respond to the one-dimensional touch location information generated by the touch controller in the self capacitance mode.

5. The computing device of claim 4, wherein said touch controller is configured to:

generate two-dimensional touch location information based on the detected mutual capacitance changes between the first and second plurality of electrodes.

6. The computing device of claim 5, further comprising a processor configured to execute functions in response to receipt of the one-dimensional touch location information from the touch controller during periods when no images are being displayed by the liquid crystal display panel.

7. The computing device of claim 4, wherein:

said second plurality of electrodes comprises a plurality of substantially linear electrodes arranged in a first direction; and

said touch controller is configured to generate swipe gesture information in response to a sequential detection of self capacitance changes in adjacent electrodes in the second plurality of electrodes over a period of time.

8. The computing device of claim 4, wherein said touch controller is configured to generate touch gesture information in response to detection of self capacitance changes in a set of adjacent electrodes in the second plurality of electrodes for a period of time.

9. The computing device of claim 4, wherein said display controller is configured to drive the first plurality of electrodes to control a liquid crystal layer in the liquid crystal display panel.

10. The computing device of claim 9, wherein said touch controller is configured to operate in the self capacitance mode while the display controller is not driving the first plurality of electrodes to control the liquid crystal layer.

11. The computing device of claim 4, wherein said touch controller is configured to operate in the self capacitance mode while the display controller is not driving the first plurality of electrodes for mutual capacitance measurements.

12. The computing device of claim 4, wherein said touch controller is configured to continue operating in the self capacitance mode while images are not being produced by the liquid crystal display panel.

13. The computing device of claim 4, wherein:

said liquid crystal display panel comprises a plurality of layers including a thin film transistor (TFT) layer; and

said first plurality of electrodes are provided in the TFT layer.

14. The computing device of claim 13, wherein said plurality of layers in the liquid crystal display panel further includes:

a color filter layer, said second plurality of electrodes being positioned on the color filter layer; and

a liquid crystal layer positioned between the TFT layer and the color filter layer.

15. The computing device of claim 4, wherein said computing device is configured to remain in a body proximity state while the touch controller is detecting self capacitance changes indicating proximity to a user'"'"'s body over a minimum threshold region.

16. The computing device of claim 15, wherein said computing device is configured to remain in a body proximity state while the touch controller is detecting self capacitance changes across substantially all of the second plurality of electrodes.

17. The computing device of claim 15, wherein said body proximity state comprises a state in which the computing device does not produce images on the display panel and does not drive the first plurality of electrodes for mutual capacitance measurements.

18. The computing device of claim 4, wherein said computing device is configured to wake from a sleep mode when the touch controller detects self capacitance changes indicative of a predefined user input pattern.

19. The computing device of claim 18, wherein said predefined user input pattern comprises a one-dimensional swipe or a temporal series of predefined one-dimensional inputs.

26. The device of claim 4, wherein the at least one processor is programmed to interpret a first direction of one-dimensional touch movement detected in the self capacitance mode as a first user input and to interpret a second direction of one-dimensional touch movement detected in the self capacitance mode as a second user input different than the first user input.

28. The device of claim 4, wherein the one-dimensional touch location information comprises touch movement information.

20. A method of operating a computing device with a processor and a liquid crystal display panel having a first and second plurality of electrodes, comprising:

driving, by a display controller, a first plurality of electrodes to control a liquid crystal layer in the liquid crystal display panel;

driving, by the display controller, the first plurality of electrodes for mutual capacitance measurements;

when displaying an image on the liquid crystal display panel, performing a mutual capacitance scan between the first plurality of electrodes and a second plurality of electrodes using a touch controller;

generating, by the touch controller, touch location information based on mutual capacitance changes detected between the first and second plurality of electrodes;

when no image is displayed on the liquid crystal display panel, performing a self capacitance scan using the touch controller and the second plurality of electrodes; and

generating, by the touch controller, one-dimensional touch location information based on self capacitance changes detected in the second plurality of electrodes in said self capacitance scan and not generating two-dimensional touch location information based on self capacitance changes; and

responding, by the processor, to the one-dimensional touch location information generated by the touch controller based on self capacitance changes.

21. The method of claim 20, wherein:

said generating touch location information based on mutual capacitance changes comprises generating two-dimensional touch location information based on the detected mutual capacitance changes between the first and second plurality of electrodes.

22. The method of claim 20, further comprising instructing the display controller to cease driving the first plurality of electrodes when the touch controller is performing the self capacitance scan.

23. The method of claim 20, further comprising instructing the display controller to cease driving the first plurality of electrodes for mutual capacitance measurements when the touch controller is performing the self capacitance scan.

24. The method of claim 20, further comprising:

in response to detecting self capacitance changes indicating proximity to a user'"'"'s body over a minimum threshold region, instructing the display controller to cease driving the first plurality of electrodes to produce images on the display panel.

25. The method of claim 20, further comprising:

in response to detecting self capacitance changes indicative of a predefined gesture, waking the computing device from the sleep mode.

27. The method of claim 20, further comprising:

interpreting a first direction of one-dimensional touch movement based on self capacitance changes as a first user input; and

interpreting a second direction of one-dimensional touch movement based on self capacitance changes as a second user input different than the first user input.

29. The method of claim 20, wherein the one-dimensional touch location information comprises touch movement information.