IN-CELL TOUCH FOR LED

• US 20140225838A1
• Filed: 02/13/2013
• Published: 08/14/2014
• Est. Priority Date: 02/13/2013
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Chang, Shih Chang, Chang, Ting-Kuo, GUPTA, Vasudha, Park, Young-Base
• Granted Patent: US 9,336,723 B2
• Time in Patent Office: Days
• US Class Current: 345/173
• CPC Class Codes: G06F 2203/04103 Manufacturing, i.e. details related to manufacturing processes specially suited for touch sensitive devices
• 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 3/04184 Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally
• CPC Class Codes: G06F 3/044 by capacitive means
• CPC Class Codes: G06F 3/0443 using a single layer of sensing electrodes
• CPC Class Codes: G09G 2300/0861 with additional control of the display period without amending the charge stored in a pixel memory, e.g. by means of additional select electrodes
• CPC Class Codes: G09G 2300/0866 by means of changes in the pixel supply voltage
• CPC Class Codes: G09G 3/3208 organic, e.g. using organic light-emitting diodes [OLED]
• CPC Class Codes: G09G 3/3233 with pixel circuitry controlling the current through the light-emitting element
• CPC Class Codes: G09G 3/34 by control of light from an independent source
• CPC Class Codes: H10K 59/40 OLEDs integrated with touch screens

Abstract

A touch screen having touch circuitry integrated into a display pixel stackup. The touch screen can include a transistor layer, an LED layer and a first layer. The first layer can operate as an LED cathode during a display phase and as touch circuitry during a touch sensing phase. The transistor layer can be at least partially utilized for transitioning between the display phase and the touch sensing phase. The touch screen can be fabricated to reduce or eliminate damage to the LED layer.

Claims

1. A touch screen comprising:

a transistor layer;

a first layer disposed over the transistor layer and configured to operate as a light-emitting diode (LED) cathode during a display phase and as touch circuitry during a touch sensing phase; and

an LED layer disposed between the transistor layer and the first layer.

2. The touch screen of claim 1, wherein the LED layer comprises an organic light-emitting diode (OLED) layer.

3. The touch screen of claim 1, wherein the transistor layer comprises:

a first transistor connected to the LED layer; and

a power supply line connected to the first transistor.

4. The touch screen of claim 3, wherein during the display phase, the power supply line voltage is set to a first voltage, and during the touch sensing phase, the power supply line voltage is set to a second voltage.

5. The touch screen of claim 4, wherein the first voltage causes the LED layer to emit light, and the second voltage causes the LED layer to not emit light.

6. The touch screen of claim 3, further comprising:

a second transistor connected to the first transistor; and

a gate voltage line connected to a gate terminal of the second transistor,

wherein during the display phase, the gate voltage line is set to a first voltage, and during the touch sensing phase, the gate voltage line is set to a second voltage.

7. The touch screen of claim 6, wherein the first voltage causes the second transistor to turn on, and the second voltage causes the second transistor to turn off.

8. The touch screen of claim 1, wherein the first layer comprises a plurality of drive lines and a plurality of sense lines.

9. The touch screen of claim 8, wherein a drive line comprises:

a first drive line segment; and

a second drive line segment electrically connected to the first drive line segment by a drive line connection.

10. A method for operating a touch screen comprising:

operating, during a display phase, a first layer as a cathode of a light-emitting diode (LED) layer; and

operating, during a touch sensing phase, the first layer as touch circuitry.

11. The method of claim 10, wherein operating the first layer as the cathode of the LED layer comprises operating the first layer as the cathode of an organic light-emitting diode (OLED) layer.

12. The method of claim 10, wherein:

operating the first layer as the cathode of the LED layer comprises setting the voltage of a power supply line connected to a transistor to a first voltage that causes the LED layer to emit light, and

operating the first layer as touch circuitry comprises setting the voltage of the power supply line to a second voltage that causes the LED layer to not emit light.

13. The method of claim 10, wherein operating the first layer as touch circuitry comprises:

operating the first layer as a plurality of drive line segments and a plurality of sense lines; and

electrically connecting a first drive line segment to a second drive line segment.

14. A method for fabricating a light-emitting diode (LED) touch screen, the method comprising:

forming a plurality of LED layers; and

forming, over the LED layers, a plurality of regions of a first layer configurable to operate as a plurality of LED cathodes during a display phase and as touch circuitry during a touch sensing phase.

15. The method of claim 14, wherein forming the plurality of LED layers comprises forming a plurality of organic light-emitting diode (OLED) layers.

16. The method of claim 14, wherein forming the plurality of regions of the first layer comprises:

depositing the first layer over the LED layers; and

removing portions of the first layer to form regions of the first layer.

17. The method of claim 14, wherein forming the plurality of regions of the first layer comprises:

depositing the first layer over the LED layers; and

oxidizing portions of the first layer to form regions of the first layer.

18. The method of claim 16, further comprising:

depositing a second layer over the first layer; and

removing portions of the second layer to form regions of the second layer,

wherein the second layer protects the LED layer from the removal of portions of the first layer and the second layer.

19. The method of claim 18, wherein removing portions of the first layer and the second layer comprises etching portions of the first layer and the second layer.

20. The method of claim 16, wherein removing portions of the first layer comprises laser ablating portions of the first layer.

21. The method of claim 14, wherein forming the plurality of regions of the first layer comprises depositing the first layer using a shadow mask.

22. The method of claim 14, further comprising modifying the dimensions of an LED layer at a boundary of one of the plurality of regions of the first layer.

23. The method of claim 14, wherein forming the plurality of regions of the first layer comprises:

forming, of the first layer, a plurality of drive line segments and a plurality of sense lines; and

electrically connecting a first drive line segment to a second drive line segment using a drive line connection.

24. The method of claim 23, further comprising forming the drive line connection over the first layer.

25. The method of claim 23, further comprising forming the drive line connection under the first layer.