PANEL BOOTSTRAPING ARCHITECTURES FOR IN-CELL SELF-CAPACITANCE

• US 20170139539A1
• Filed: 05/22/2014
• Published: 05/18/2017
• Est. Priority Date: 05/22/2014
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: YAO, Weijun, NHO, Hyunwoo, SYED, Taif A., AL-DAHLE, Ahmad, YAO, Wei Hsin, LI, Yingxuan
• Granted Patent: US 10,936,120 B2
• Time in Patent Office: 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 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 3/0416 Control or interface arrangements specially adapted for digitisers
• 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 3/0418 for error correction or compensation, e.g. based on parallax, calibration or alignment
• CPC Class Codes: G06F 3/044 by capacitive means
• 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
• CPC Class Codes: H01L 27/124 with a particular composition, shape or layout of the wiring layers specially adapted to the circuit arrangement, e.g. scanning lines in LCD pixel circuits wiring structures per se H01L23/52
• CPC Class Codes: H01L 27/1255 integrated with passive devices, e.g. auxiliary capacitors

Abstract

A self-capacitance touch screen. In some examples, the touch screen comprises a plurality of display pixels, a first display pixel of the plurality of display pixels including a first touch electrode of a plurality of touch electrodes, and a gate line coupled to the first display pixel, wherein the gate line is configured such that a voltage at the gate line substantially follows a voltage at the first touch electrode. In some examples, the gate line is coupled to a resistor, the resistor being configured to decouple the gate line from ground. In some examples, the gate line is coupled to an AC voltage source.

Claims

1. A self-capacitance touch screen, the touch screen comprising:

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

a gate line coupled to the first display pixel, wherein the gate line is configured such that a voltage at the gate line substantially follows a voltage at the first touch electrode.

2. The touch screen of claim 1, wherein the touch screen is configured to enable an AC voltage to be present at both the gate line and the first touch electrode.

3. The touch screen of claim 1, wherein the gate line is coupled to a resistor, the resistor being configured to decouple the gate line from ground.

4. The touch screen of claim 3, wherein the resistor is in a border region of the touch screen.

5. The touch screen of claim 3, wherein the resistor is coupled to an AC voltage source.

6. The touch screen of claim 5, wherein:

the AC voltage source is coupled to sense circuitry, and

the sense circuitry is coupled to the first touch electrode.

7. The touch screen of claim 1, wherein the gate line is coupled to an AC voltage source.

8. The touch screen of claim 7, further comprising sense circuitry coupled to:

the first touch electrode, and

the AC voltage source.

9. The touch screen of claim 7, wherein the gate line is further coupled to a DC voltage source.

10. The touch screen of claim 1, wherein the gate line is coupled to a transistor in the first display pixel.

11. The touch screen of claim 1, wherein the gate line is further coupled to a second display pixel of the plurality of display pixels.

12. A method for operating a self-capacitance touch screen, the method comprising:

coupling a gate line to a first display pixel of a plurality of display pixels, the first display pixel including a first touch electrode of a plurality of touch electrodes; and

operating the gate line such that a voltage at the gate line substantially follows a voltage at the first touch electrode.

13. The method of claim 12, wherein the voltage at the gate line and the voltage at the first touch electrode comprise an AC voltage.

14. The method of claim 12, wherein operating the gate line comprises coupling the gate line to a resistor, the resistor being configured to decouple the gate line from ground.

15. The method of claim 14, wherein the resistor is in a border region of the touch screen.

16. The method of claim 14, further comprising coupling the resistor to an AC voltage source.

17. The method of claim 16, further comprising:

coupling the AC voltage source to sense circuitry; and

coupling the sense circuitry to the first touch electrode.

18. The method of claim 12, wherein operating the gate line comprises coupling the gate line to an AC voltage source.

19. The method of claim 18, further comprising coupling the first touch electrode and the AC voltage source to sense circuitry.

20. The method of claim 18, further comprising coupling the gate line to a DC voltage source.

21. The method of claim 12, wherein coupling the gate line to the first display pixel comprises coupling the gate line to a transistor in the first display pixel.

22. The method of claim 12, further comprising coupling the gate line to a second display pixel of the plurality of display pixels.

23. A self-capacitance touch screen, the touch screen comprising:

a plurality of display pixels, a first display pixel of the plurality of display pixels including a first touch electrode of a plurality of touch electrodes;

a gate line coupled to the first display pixel; and

circuitry configured to apply substantially similar voltage signals at the gate line and the first touch electrode.

24. The touch screen of claim 23, wherein the gate line is further coupled to a second display pixel of the plurality of display pixels.

25. The touch screen of claim 23, wherein the circuitry comprises:

an AC voltage source coupled to the gate line and to sense circuitry, the sense circuitry being coupled to the first touch electrode.

26. The touch screen of claim 25, wherein:

the sense circuitry comprises an operational amplifier,

the AC voltage source is coupled to a non-inverting input of the operational amplifier, and

the first touch electrode is coupled to an inverting input of the operational amplifier.

27. The touch screen of claim 25, wherein the circuitry further comprises a resistor through which the AC voltage source is coupled to the gate line.