Light emitting diode display with redundancy scheme

• US 8,791,474 B1
• Filed: 03/15/2013
• Issued: 07/29/2014
• Est. Priority Date: 03/15/2013
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: LuxVue Techonology Corporation (Apple Inc.)
• Inventors: Bibl, Andreas, Sakariya, Kapil V., Griggs, Charles R., Perkins, James Michael
• Primary Examiner(s): Nguyen, Khiem D
• Application Number:
  US13/842,879
• Time in Patent Office: 501 Days
• Field of Search: 257/88, 257/89, 257/99, 257/100, 257/E33.001, 438/22, 438/28, 438/30, 438/34, 438/38, 438/42, 438/44, 349/192
• US Class Current: 257/89
• CPC Class Codes: G09G 2300/0426 Layout of electrodes and connections
• CPC Class Codes: G09G 2330/021 Power management, e.g. power saving
• CPC Class Codes: G09G 2330/08 Fault-tolerant or redundant circuits, or circuits in which repair of defects is prepared
• CPC Class Codes: G09G 3/2003 Display of colours specific for liquid crystal displays G09G3/3607
• CPC Class Codes: G09G 3/3208 organic, e.g. using organic light-emitting diodes [OLED]
• CPC Class Codes: H01L 25/0753 the devices being arranged next to each other
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00

Abstract

A display panel and method of manufacture are described. In an embodiment, a display substrate includes a pixel area and a non-pixel area. An array of subpixels and corresponding array of bottom electrodes are in the pixel area. An array of micro LED devices are bonded to the array of bottom electrodes. One or more top electrode layers are formed in electrical contact with the array of micro LED devices. In one embodiment a redundant pair of micro LED devices are bonded to the array of bottom electrodes. In one embodiment, the array of micro LED devices are imaged to detect irregularities.

Claims

1. A display panel with redundancy scheme comprising:

a display substrate including a pixel area and a non-pixel area, wherein the pixel area includes an array of subpixels and a corresponding array of bottom electrodes within the array of subpixels;

an array of redundant micro LED device pairs bonded to the array of bottom electrodes, wherein each subpixel includes a bottom electrode and a redundant micro LED device pair bonded to the bottom electrode, and each redundant micro LED device pair within a respective subpixel is designed to emit a same primary color emission; and

one or more top electrode layers in electrical contact with the array of redundant micro LED device pairs;

wherein the array of redundant micro LED device pairs comprises a first array of redundant micro LED device pairs, a second array of redundant micro LED device pairs, and a third array of redundant micro LED device pairs, wherein the first, second, and third arrays of redundant micro LED device pairs are designed to emit different primary color emissions.

2. The display panel of claim 1, wherein each micro LED device is formed of a semiconductor material.

3. The display panel of claim 2, wherein each micro LED device has a maximum width of 1 to 100 μ

m.

4. The display panel of claim 2, wherein the display substrate is a thin film transistor substrate.

5. The display panel of claim 4, further comprising a ground line in the non-pixel area of the thin film transistor substrate, wherein the one or more top electrode layers are electrically connected to the ground line.

6. The display panel of claim 5, wherein the one or more top electrode layers comprise a first top electrode layer electrically connecting a first micro LED device of a redundant micro LED device pair to the ground line, and a separate second top electrode layer electrically connecting a second micro LED device of the redundant micro LED device pair to the ground line.

7. The display panel of claim 2, further comprising an array of micro controller chips bonded to the display substrate, wherein each bottom electrode is electrically connected to a micro controller chip.

8. The display panel of claim 7, wherein each micro controller chip is connected to a scan driver circuit and a data driver circuit.

9. The display panel of claim 8, further comprising a ground line in the non-pixel area of the display substrate, wherein the one or more top electrode layers are electrically connected to the ground line.

10. The display panel of claim 9, wherein the one or more top electrode layers comprise a first top electrode layer electrically connecting a first micro LED device of a redundant micro LED device pair to the ground line, and a separate second top electrode layer electrically connecting a second micro LED device of the redundant micro LED device pair to the ground line.

11. The display panel of claim 2, further comprising:

a plurality of micro LED device irregularities within the array of redundant micro LED device pairs, the irregularities selected from the group consisting of missing micro LED devices, defective micro LED devices, and contaminated micro LED devices; and

a passivation layer material covering the plurality of irregularities.

12. The display panel of claim 11, wherein the one or more top electrode layers do not make electrical contact with the plurality of irregularities.

13. The display panel of claim 12, wherein the one or more top electrode layers are formed directly over the plurality of irregularities.

14. The display panel of claim 12, wherein the one or more top electrode layers are not formed directly over the plurality of irregularities.

15. The display panel of claim 12, wherein the plurality of micro LED device irregularities are missing micro LED devices.

16. The display panel of claim 15, further comprising an array of bonding layers on the array of bottom electrodes corresponding to the plurality of missing micro LED devices, wherein the passivation layer material covers the array of bonding layers.

17. The display panel of claim 12, wherein the plurality of micro LED device irregularities are defective micro LED devices and the passivation layer material covers the defective micro LED devices.

18. The display panel of claim 12, wherein the plurality of micro LED device irregularities are contaminated micro LED devices and the passivation layer material covers the contaminated micro LED devices.

19. The display panel of claim 11, wherein the passivation layer material covers sidewalls of the array of redundant micro LED device pairs.

20. The display panel of claim 11, further comprising a repair micro LED device bonded to one of the bottom electrodes including one of the micro LED device irregularities.

21. The display panel of claim 4, wherein each subpixel and corresponding redundant micro LED device pair bonded to a corresponding bottom electrode is independently addressable by the thin film transistor substrate.

22. The display panel of claim 7, wherein each subpixel and corresponding redundant micro LED device pair bonded to a corresponding bottom electrode is independently addressable by a micro controller chip.

23. The display panel of claim 22, wherein each micro controller chip is bonded to the display substrate within the pixel area, and the each micro controller chip is connected to a scan driver circuit and a data driver circuit that is not bonded to the display substrate within the pixel area.

24. The display panel of claim 1, wherein the first array of redundant micro LED device pairs is designed to emit a red primary color emission, the second array of redundant micro LED device pairs is designed to emit a green primary color emission, and the third array of emitting redundant micro LED device pairs is designed to emit a blue primary color emission.

25. The display panel of claim 1, wherein each micro LED device is bonded to a bottom electrode with an electrically conductive bonding layer directly between the micro LED device and the bottom electrode.

26. The display panel of claim 25, wherein the electrically conductive bonding layer comprises a solder material.

27. The display panel of claim 11, wherein the display substrate is a thin film transistor substrate.