Reducing touch pixel coupling

• US 9,535,544 B2
• Filed: 05/31/2013
• Issued: 01/03/2017
• Est. Priority Date: 05/31/2013
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Syed, Taif Ahmed, Yousefpor, Marduke, Al-Dahle, Ahmad, White, Kevin J., Jamshidi-Roudbari, Abbas, Poon, Stephen S.
• Primary Examiner(s): Leiby, Christopher E
• Application Number:
  US13/907,698
• Publication Number:
  US 20140354586A1
• Time in Patent Office: 1,313 Days
• US Class Current: 1/1
• CPC Class Codes: G06F 2203/04107 Shielding in digitiser, i.e. guard or shielding arrangements, mostly for capacitive touchscreens, e.g. driven shields, driven grounds
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/0443 using a single layer of sensing electrodes
• 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

A touch screen to reduce touch pixel coupling. In some examples, the touch screen can include a first display pixel and a second display pixel in a row of display pixels, where the first display pixel can be configurable to be decoupled from the second display pixel during at least a touch sensing phase of the touch screen. In some examples, the touch screen can include a display pixel having a first and a second transistor, where the second transistor can be electrically connected to a gate terminal of the first transistor, and can be diode-connected. In some examples, the touch screen can include two display pixels, each display pixel having two transistors, where two of the transistors can be electrically connected to a first gate line, and the remaining two transistors can be individually electrically connected to a second and third gate line, respectively.

Claims

1. A touch screen comprising:

a first drive region;

a first sense region; and

a first display pixel in the first drive region coupled to a first gate line, wherein the first display pixel includes a first transistor, and wherein the first transistor includes a first gate; and

a second display pixel in the first sense region coupled to a second gate line, different from the first gate line, wherein the second display pixel includes a second transistor, and wherein the second transistor includes a second gate;

wherein the first gate line is coupled to the first gate and the second gate line is coupled to the second gate, wherein the first gate line is decoupled from the second gate line during at least a touch sensing phase of the touch screen, and wherein the first gate line is coupled to the second gate line at least during a display phase of the touch screen.

2. The touch screen of claim 1, further comprising a third display pixel in a second drive region of the touch screen, wherein the first gate line is coupled to the third display pixel.

3. The touch screen of claim 1, further comprising a third display pixel in a second sense region of the touch screen, wherein the second gate line is coupled to the third display pixel.

4. The touch screen of claim 1, further comprising a decoupling portion between the first and second gate lines.

5. The touch screen of claim 4, wherein the decoupling portion comprises a capacitor electrically connected to a diode.

6. The touch screen of claim 4, wherein the decoupling portion comprises a diode electrically connected to a transistor.

7. The touch screen of claim 4, wherein the decoupling portion comprises a transistor controlled by a timing signal, the timing signal controlling a transition between the touch sensing phase and the display phase of the touch screen.

8. The touch screen of claim 4, wherein the decoupling portion comprises a first diode and a second diode electrically connected in a ring configuration.

9. The touch screen of claim 4, wherein the decoupling portion comprises:

a switch controlled by a timing signal, the timing signal controlling a transition between the touch sensing phase and the display phase of the touch screen; and

a diode electrically connected to the switch.

10. The touch screen of claim 1, wherein the first gate line is configured to pass through the first sense region.

11. The touch screen of claim 10, wherein the second gate line is configured to pass through the first drive region.

12. The touch screen of claim 10, wherein the first sense region further comprises a first sense electrode, and the first gate line is configured to pass underneath the first sense electrode.

13. The touch screen of claim 12, wherein the first sense electrode is configured to operate as at least a portion of touch sensing circuitry during the touch sensing phase of the touch screen and is configured to further operate as at least a portion of a display sensing circuitry during the display phase of the touch screen.

14. The touch screen of claim 1, further comprising a third display pixel in the first sense region.

15. The touch screen of claim 14, wherein the third display pixel is coupled to the second gate line and is aligned with the first and second display pixels in the first direction.

16. The touch screen of claim 14, wherein the third display pixel is coupled to a third gate line, wherein the third gate line is decoupled from the first and second gate line and the third display pixel is aligned with the second display pixel in a second direction, perpendicular to the first direction.

17. The touch screen of claim 14, wherein the second display pixel and the third display pixel are immediately adjacent to one another.

18. The touch screen of claim 1, wherein the second gate line is parallel to the first gate line.

19. A method for operating a touch screen, the method comprising:

providing a first drive region and a first sense region;

applying a first voltage to a first gate line coupled to a first display pixel in the first drive region, wherein the first display pixel includes a first transistor, and wherein the first transistor includes a first gate; and

applying a second voltage to a second gate line coupled to a second display pixel in the first sense region, wherein the second display pixel includes a second transistor, and wherein the second transistor includes a second gate;

wherein the first gate line is coupled to the first gate and the second gate line is coupled to the second gate, wherein the first gate line is decoupled from the second gate line during at least a touch sensing phase of the touch screen, and wherein the first gate line is coupled to the second gate line at least during a display phase of the touch screen.

20. The method of claim 19, wherein:

a third display pixel in a second drive region of the touch screen is coupled to the first gate line; and

a fourth display pixel in a second sense region of the touch screen is coupled to the second gate line.

21. The method of claim 19, further comprising:

electrically connecting the first gate line to the second gate line via a decoupling portion between the first and second gate lines.

22. The method of claim 19, wherein the first gate line passes through the first sense region.

23. The method of claim 22, wherein the second gate line passes through the first drive region.

24. The method of claim 22, wherein the first sense region further comprises a first sense electrode, and the first gate line is configured to pass underneath the first sense electrode.

25. The method of claim 24, wherein the first sense electrode is configured to operate as at least a portion of touch sensing circuitry during the touch sensing phase of the touch screen, and is configured to further operate as at least a portion of a display sensing circuitry during a display phase of the touch screen.

26. The method of claim 19, wherein the second gate line is parallel to the first gate line.