INTEGRATED TOUCH AND DISPLAY ARCHITECTURES FOR SELF-CAPACITIVE TOUCH SENSORS

• US 20170090644A1
• Filed: 09/30/2014
• Published: 03/30/2017
• Est. Priority Date: 12/13/2013
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: YANG, Bingrui, YAO, Weijun, YAO, Wei Hsin, LI, Yingxuan, YOUSEFPOR, Marduke, JAMSHIDI-ROUDBARI, Abbas, AL-DAHLE, Ahmad
• Granted Patent: US 10,209,813 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• 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 3/0446 using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes
• CPC Class Codes: H04L 12/12 Arrangements for remote connection or disconnection of substations or of equipment thereof
• CPC Class Codes: H10K 59/1216 the pixel elements being capacitors
• CPC Class Codes: H10K 59/123 Connection of the pixel electrodes to the thin film transistors [TFT]
• CPC Class Codes: H10K 59/40 OLEDs integrated with touch screens
• CPC Class Codes: Y02D 30/50 in wire-line communication networks, e.g. low power modes or reduced link rate

Abstract

A self-capacitive touch sensor panel configured to have a portion of both the touch and display functionality integrated into a common layer is provided. The touch sensor panel includes a layer with circuit elements that can switchably operate as both touch circuitry and display circuitry such that during a touch mode of the device the circuit elements operate as touch circuitry and during a display mode of the device the circuit elements operate as display circuitry. The touch mode and display mode can be time multiplexed. By integrating the touch hardware and display hardware into common layers, savings in power, weight and thickness of the device can be realized.

Claims

1. A touch sensitive device including a plurality of display pixels, the touch sensitive device comprising:

a TFT layer, the TFT layer comprising a plurality of circuit elements that are configurable as a plurality of self-capacitance touch pixel electrodes during a touch detection mode of the device, and are configurable as display circuitry during a display mode of the device, wherein each of the plurality of self-capacitance touch pixel electrodes is electrically isolated from others of the plurality of self-capacitance touch pixel electrodes, and wherein each of the plurality of self-capacitance touch pixel electrodes represents a unique touch location on a touch sensor panel;

a plurality of conductive wires, each wire of the plurality of conductive wires configured to transmit a touch signal from one of the plurality of circuit elements to a touch controller of the device; and

one or more processing units configured to switch the device between the touch detection mode and the display mode,

wherein during the touch detection mode, the plurality of circuit elements are configured as self-capacitance touch pixel electrodes, and during the display mode, the plurality of circuit elements are biased at a common voltage.

2. The device of claim 1, wherein the one or more processing units comprise the touch controller.

3. The device of claim 2, wherein:

the touch controller comprises a plurality of sense circuits, and

the plurality of conductive wires are configured to transmit the touch signals to the plurality of sense circuits.

4. The device of claim 1, wherein the touch detection mode of the device and the display mode of the device are time multiplexed.

5. The device of claim 1, wherein:

a first conductive wire of the plurality of conductive wires has a first width and a first length, and

a second conductive wire of the plurality of conductive wires has a second width and a second length, the second length being greater than the first length, the second width being greater than the first width such that a first resistance of the first conductive wire is substantially equal to a second resistance of the second conductive wire.

6. The device of claim 1, further comprising:

a wire matrix disposed in a non-active area of a display comprising the plurality of display pixels, the wire matrix configured to transmit display control signals to the plurality of display pixels during the display mode.

7. An organic light emitting diode (OLED) touch sensitive device including a plurality of display pixels, the device comprising:

an anode layer; and

a cathode layer, the cathode layer comprising a plurality of circuit elements that are configurable as a plurality of self-capacitance touch pixel electrodes during a touch detection mode of the device, and are configurable as a cathode for an OLED display during a display mode of the device, wherein each of the plurality of self-capacitance touch pixel electrodes is electrically isolated from others of the plurality of self-capacitance touch pixel electrodes, and wherein each of the plurality of self-capacitance touch pixel electrodes represents a unique touch location on a touch sensor panel.

8. The device of claim 7, the device further comprising:

a stimulation circuit, the stimulation circuit configured to stimulate the self-capacitance touch pixel electrodes during the touch detection mode of the device; and

a bootstrapping circuit, the bootstrapping circuit configured to stimulate the anode layer of the device with substantially the same signal as being used by the stimulation circuit to stimulate the self-capacitance touch pixel electrodes during the touch detection mode of the device.

9. The device of claim 7, wherein:

the anode layer comprises a plurality of anode elements, and

during the display mode of the device, each of the plurality of circuit elements is electrically coupled to a respective anode element of the plurality of anode elements.

10. The device of claim 9, wherein each of the plurality of circuit elements is electrically coupled to a respective anode element of the plurality of anode elements via an organic layer comprising a plurality of organic light emitting diodes.

11. The device of claim 8, wherein a DC current between the anode layer and the self-capacitance touch pixel electrodes remains substantially constant during the touch detection mode of the device.

12. The device of claim 7, wherein the touch detection mode of the device and the display mode of the device are time multiplexed.

13. An organic light emitting diode touch sensitive device including a plurality of display pixels, the device comprising:

a cathode layer;

an ITO layer, the ITO layer configurable as a plurality of self-capacitive touch sensors during a touch detection mode of the device, and configurable as an anode layer during a display mode of the device, wherein each of the plurality of self-capacitive touch sensors is electrically isolated from others of the plurality of self-capacitive touch sensors, and wherein each of the plurality of self-capacitive touch sensors represents a unique touch location on a touch sensor panel; and

an encapsulation layer disposed between the cathode layer and the ITO layer.

14. The device of claim 13, further comprising:

a metal layer, the metal layer connected to the ITO layer through a plurality of vias.

15. The device of claim 13, further comprising:

a cancellation circuit, the cancellation circuit coupled to the ITO layer and configured to cancel a parasitic capacitance effect of one or more of the self-capacitive touch sensors.

16. The device of claim 15, wherein:

the parasitic capacitance effect comprises an offset current, and

the cancellation circuit is configured to cancel the parasitic capacitance effect by at least producing an offset cancellation current to offset the offset current.

17. The device of claim 15, wherein an operation of the cancellation circuit is determined when no touch event is occurring at the device.

18. The device of claim 13, wherein the touch detection mode of the device and the display mode of the device are time multiplexed.