Coupling correction in capacitive touch panels

• US 10,042,484 B1
• Filed: 09/02/2014
• Issued: 08/07/2018
• Est. Priority Date: 09/02/2014
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: O'Connor, Sean E.
• Primary Examiner(s): Edwards, Mark
• Application Number:
  US14/474,571
• Time in Patent Office: 1,435 Days
• 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 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 3/04166 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 3/04186 Touch location disambiguation
• CPC Class Codes: G06F 3/0443 using a single layer of sensing electrodes

Abstract

A touch screen is disclosed. In some examples, the touch screen comprises a touch sensor panel including a plurality of touch pixels that include a first and a second touch pixel, a first sense connection coupled to the first touch pixel, and a second sense connection coupled to the second touch pixel. In some examples, a touch controller is configured to detect an object coupled to the first touch pixel and the second sense connection, and in response to detecting the object, output substantially no touch signal associated with the second touch pixel. In some examples, the touch controller is further configured to scale a first touch signal associated with the first touch pixel by a first correction coefficient corresponding to the first touch pixel and the second touch pixel, and subtract the scaled first touch signal from a second touch signal associated with the second touch pixel.

Claims

1. A touch screen comprising:

a touch sensor panel including;

a plurality of touch pixel electrodes, the plurality of touch pixel electrodes including a first touch pixel electrode and a second touch pixel electrode;

a first sense connection coupled to the first touch pixel electrode; and

a second sense connection coupled to the second touch pixel electrode and

a touch controller configured to;

detect an object coupled to the first touch pixel electrode and the second sense connection resulting in a first amount of touch associated with the first touch pixel electrode and a second amount of touch associated with the second touch pixel electrode; and

in response to detecting the object;

in accordance with a determination that the first amount of touch associated with the first touch pixel electrode exceeds a touch threshold and independent of the second amount of touch associated with the second touch pixel electrode, apply a first touch correction to the second amount of touch associated with the second touch pixel electrode; and

in accordance with a determination that the first amount of touch associated with the first touch pixel electrode does not exceed the touch threshold, forgo applying the first touch correction to the second amount of touch associated with the second touch pixel electrode.

2. The touch screen of claim 1, wherein:

the second sense connection is further coupled to a second bond pad,

the object is further coupled to the second bond pad, and

the touch controller is configured to;

detect the object coupled to the first touch pixel electrode, the second sense connection and the second bond pad, and

in response to detecting the object, output substantially no touch signal associated with the second touch pixel electrode.

3. The touch screen of claim 1, wherein the touch controller is further configured to scale the first amount of touch associated with the first touch pixel electrode by a first correction coefficient corresponding to the first touch pixel electrode and the second touch pixel electrode, and subtract the scaled first amount of touch from the second amount of touch associated with the second touch pixel electrode.

4. The touch screen of claim 1, wherein the second sense connection is disposed adjacent to the first touch pixel electrode on the touch screen.

5. The touch screen of claim 2, wherein the second bond pad is disposed adjacent to the first touch pixel electrode on the touch screen.

6. The touch screen of claim 1, wherein the first touch pixel electrode and the second touch pixel electrode comprise self-capacitance touch pixel electrodes.

7. A touch controller comprising:

sense circuitry configured to;

detect a first touch signal at a first touch pixel on a touch sensor panel, and

detect a second touch signal at a second touch pixel on the touch sensor panel; and

a touch processor configured to, in response to the detection of the first touch signal at the first touch pixel;

in accordance with a determination that the first touch signal exceeds a threshold signal and independent of the second touch signal, reduce the second touch signal by an amount based on the first touch signal; and

in accordance with a determination that the first touch signal does not exceed the threshold signal, forgo reducing the second touch signal by the amount based on the first touch signal.

8. The touch controller of claim 7, wherein:

the sense circuitry is further configured to detect a third touch signal at a third touch pixel on the touch sensor panel, and

the touch processor is further configured to, in response to the detection of the third touch signal at the third touch pixel, further reduce the second touch signal based on the third touch signal.

9. The touch controller of claim 8, wherein reducing the second touch signal based on the first touch signal comprises:

scaling the first touch signal by a first correction coefficient corresponding to the first touch pixel and the second touch pixel, and subtracting the scaled first touch signal from the second touch signal; and

scaling the third touch signal by a second correction coefficient corresponding to the second touch pixel and the third touch pixel, different from the first correction coefficient, and subtracting the scaled third touch signal from the second touch signal.

10. The touch controller of claim 7, wherein:

the sense circuitry is further configured to detect a third touch signal at a third touch pixel on the touch sensor panel, and

the touch processor is further configured to, in response to the detection of the first touch signal at the first touch pixel, reduce the third touch signal based on the first touch signal.

11. The touch controller of claim 10, wherein:

reducing the second touch signal based on the first touch signal comprises scaling the first touch signal by a first correction coefficient corresponding to the first touch pixel and the second touch pixel resulting a first scaled first touch signal, and subtracting the first scaled first touch signal from the second touch signal, and

reducing the third touch signal based on the first touch signal comprises scaling the first touch signal by a second correction coefficient corresponding to the first touch pixel and the third touch pixel, different from the first correction coefficient, resulting in a second scaled first touch signal, and subtracting the second scaled first touch signal from the third touch signal.

12. The touch controller of claim 7, wherein:

a second sense connection on the touch sensor panel is coupled to the second touch pixel and is configured to couple the second touch pixel to the sense circuitry, and

the second sense connection is adjacent to the first touch pixel on the touch sensor panel.

13. The touch controller of claim 7, wherein:

a second bond pad on the touch sensor panel is coupled to the second touch pixel and is configured to couple the second touch pixel to the sense circuitry, and

the second bond pad is adjacent to the first touch pixel on the touch sensor panel.

14. The touch controller of claim 7, wherein the first touch pixel and the second touch pixel comprise self-capacitance touch pixels.

15. The touch controller of claim 7, wherein reducing the second touch signal based on the first touch signal comprises:

scaling the first touch signal by a first correction coefficient corresponding to the second touch pixel; and

subtracting the scaled first touch signal from the second touch signal.

16. A method comprising:

detecting an object coupled to a first touch pixel electrode and a second sense connection of a touch sensor panel resulting in a first amount of touch associated with the first touch pixel electrode and a second amount of touch associated with a second touch pixel electrode, wherein the touch sensor panel includes;

a plurality of touch pixel electrodes including the first touch pixel electrode and the second touch pixel electrode;

a first sense connection coupled to the first touch pixel electrode; and

the second sense connection coupled to the second touch pixel electrode; and

in response to detecting the object;

in accordance with a determination that the first amount of touch associated with the first touch pixel electrode exceeds a touch threshold and independent of the second amount of touch associated with the second touch pixel electrode, applying a first touch correction to the second amount of touch associated with the second touch pixel electrode; and

in accordance with a determination that the first amount of touch associated with the first touch pixel electrode does not exceed the touch threshold, forgoing applying the first touch correction to the second amount of touch associated with the second touch pixel electrode.

17. The method of claim 16, wherein:

the second sense connection is further coupled to a second bond pad,

the object is further coupled to the second bond pad, and

the method further comprises;

detecting the object coupled to the first touch pixel electrode, the second sense connection and the second bond pad, and

in response to detecting the object, outputting substantially no touch signal associated with the second touch pixel electrode.

18. The method of claim 16, further comprising:

scaling a first touch signal associated with the first touch pixel electrode by a first correction coefficient corresponding to the first touch pixel electrode and the second touch pixel electrode; and

subtracting the scaled first touch signal from a second touch signal associated with the second touch pixel electrode.

19. The method of claim 16, wherein the first touch pixel electrode and the second touch pixel electrode comprise self-capacitance touch pixel electrodes.

20. A method comprising:

detecting a first touch signal at a first touch pixel on a touch sensor panel;

detecting a second touch signal at a second touch pixel on the touch sensor panel; and

in response to the detection of the first touch signal at the first touch pixel;

in accordance with a determination that the first touch signal exceeds a threshold signal and independent of the second touch signal, reducing the second touch signal by an amount based on the first touch signal;

in accordance with a determination that the first touch signal does not exceed the threshold signal, forgoing reducing the second touch signal by the amount based on the first touch signal.

21. The method of claim 20, wherein reducing the second touch signal based on the first touch signal comprises:

scaling the first touch signal by a first correction coefficient corresponding to the second touch pixel; and

subtracting the scaled first touch signal from the second touch signal.