FLEXIBLE DISPLAY

• US 20140138637A1
• Filed: 03/15/2013
• Published: 05/22/2014
• Est. Priority Date: 11/16/2012
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Yang, Byung Duk, Zhong, John Z., Chang, Shih Chang, Gupta, Vasudha, Park, Young Bae
• Granted Patent: US 9,601,557 B2
• Time in Patent Office: Days
• US Class Current: 257/40
• CPC Class Codes: H01L 27/1218 with a particular composition or structure of the substrate
• 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 27/1244 for preventing breakage, peeling or short circuiting
• CPC Class Codes: H01L 27/1248 with a particular composition or shape of the interlayer dielectric specially adapted to the circuit arrangement
• CPC Class Codes: H10K 2102/311 Flexible OLED
• CPC Class Codes: H10K 59/131 Interconnections, e.g. wiring lines or terminals

Abstract

A flexible display having an array of pixels or sub-pixels is provided. The display includes a flexible substrate and an array of thin film transistors (TFTs) corresponding to the array of pixels or sub-pixels on the substrate. The display also includes a first plurality of metal lines coupled to gate electrodes of the TFTs and a second plurality of metal lines coupled to source electrodes and drain electrodes of the TFTs. At least one of the first plurality of metal lines and the second plurality of metal lines comprises a non-stretchable portion in the TFT areas and a stretchable portion outside the TFT areas.

Claims

1. A flexible display having an array of pixels or sub-pixels, the display comprising:

a flexible substrate;

an array of thin film transistors (TFTs) corresponding to the array of pixels or sub-pixels on the substrate;

a first plurality of metal lines coupled to gate electrodes of the TFTs; and

a second plurality of metal lines coupled to source electrodes and drain electrodes of the TFTs, wherein at least one of the first plurality of metal lines and the second plurality of metal lines comprises a non-stretchable portion in the TFT areas and a stretchable portion outside the TFT areas.

2. The flexible display of claim 1, wherein the stretchable portion comprises a metal trace shaped in a pattern configured to be bendable.

3. The flexible display of claim 2, wherein the pattern comprises at least one of serpentine, sine wave, and square wave.

4. The flexible display of claim 1, wherein the pixels or sub-pixels comprise organic light emitting diode.

5. The flexible display of claim 1, further comprising a buffer layer between the substrate and the TFT.

6. The flexible display of claim 5, further comprising an active semiconductor layer over the buffer layer and a gate insulator over the active layer, wherein the gate electrode is disposed over the gate insulator.

7. The flexible display of claim 6, wherein the active semiconductor layer comprises a material selected from a group consisting of amorphous silicon, low temperature polysilicon, and metal oxide.

8. The flexible display of claim 5, wherein the buffer layer comprises a sublayer of silicon oxide and a sublayer of silicon nitride, wherein the silicon nitride comprises striation in the bendable area.

9. The flexible display of claim 5, wherein the buffer layer comprises a sublayer of silicon oxide and a sublayer of silicon nitride, wherein the silicon nitride comprises a thicker portion in the TFT area than the bendable area outside the TFT area.

10. The flexible display of claim 1, further comprising an interlayer dielectric (ILD) between the gate electrode of the TFT and the source/drain of the TFT.

11. The flexible display of claim 10, wherein the ILD comprises a sublayer of silicon oxide and a sublayer of silicon nitride, wherein the silicon nitride comprises a striation pattern in the bendable area outside the TFT area.

12. The flexible display of claim 10, wherein the ILD layer is present in the TFT area and absent outside the TFT area.

13. The flexible display of claim 1, further comprising a passivation disposed over the source electrodes and drain electrodes of the TFTs.

14. The flexible display of claim 13, wherein the passivation layer comprises a flexible organic material.

15. The flexible display of claim 1, wherein the flexible substrate comprises polyimide.

16. The flexible display of claim 1, wherein the stretchable portion of the at least one of the first plurality of metal lines and the second plurality of metal lines further comprises a first stretchable portion interleaved or overlapped with a second stretchable portion as a redundant.

17. The flexible display of claim 16, wherein the first stretchable portion is formed from the first metal for the gate electrode and gate line, and the second stretchable portion is formed from the second metal for the drain and source and data line.

18. The flexible display of claim 17, wherein the first stretchable portion and the second stretchable portion are connected at least one location outside the TFT area.

19. A flexible display having an array of pixels or sub-pixels, the display comprising:

a flexible substrate;

a buffer layer over the flexible substrate;

an array of thin film transistors (TFTs) corresponding to the array of pixels or sub-pixels on the substrate;

a first plurality of metal lines coupled to gate electrodes of the TFTs; and

a second plurality of metal lines coupled to source electrodes and drain electrodes of the TFTs;

an integration circuit (IC) board outside the TFT and pixels; and

a plurality of metal traces coupled between the TFTs and the IC board, the plurality of metal traces being formed of at least one of the first metal for gate electrode of the TFT and the second metal for source electrode and drain electrode of the TFT, wherein the plurality of metal traces being disposed over the buffer layer, wherein the buffer layer outside the TFT area is configured to have a striation pattern.

20. The flexible display of claim 19, wherein the plurality of metal traces are being configured to be stretchable.

21. The flexible display of claim 19, wherein at least one of the first plurality of metal lines and the second plurality of metal lines comprises a non-stretchable portion in the TFT areas and a stretchable portion outside the TFT areas.

22. The flexible display of claim 19, wherein the stretchable portion comprises a metal trace shaped in a pattern configured to be bendable.

23. The flexible display of claim 22, wherein the pattern comprises at least one of serpentine, sine wave, and square wave.

24. The flexible display of claim 19, wherein the pixels or sub-pixels comprise organic light emitting diode.

25. The flexible display of claim 19, further comprising a buffer layer between the substrate and the TFT.

26. The flexible display of claim 25, wherein the buffer layer comprises a sublayer of silicon oxide and a sublayer of silicon nitride, wherein the silicon nitride comprises striation in the bendable area.

27. The flexible display of claim 25, wherein the buffer layer comprises a sublayer of silicon oxide and a sublayer of silicon nitride, wherein the silicon nitride comprises a thicker portion in the TFT area than the bendable area outside the TFT area.

28. The flexible display of claim 19, further comprising an interlayer dielectric (ILD) between the gate electrode of the TFT and the source/drain of the TFT.

29. The flexible display of claim 28, wherein the ILD comprises a sublayer of silicon oxide and a sublayer of silicon nitride, wherein the silicon nitride comprises a striation pattern in the bendable area outside the TFT area.

30. The flexible display of claim 28, wherein the ILD layer is present in the TFT area and absent outside the TFT area.

31. The flexible display of claim 19, further comprising a passivation disposed over the source electrodes and drain electrodes of the TFTs.

32. The flexible display of claim 31, wherein the passivation layer comprises a flexible organic material.

33. The flexible display of claim 19, wherein the flexible substrate comprises polyimide.

34. The flexible display of claim 19, wherein the stretchable portion of the at least one of the first plurality of metal lines and the second plurality of metal lines further comprises a first stretchable portion interleaved or overlapped with a second stretchable portion as a redundant.

35. The flexible display of claim 34, wherein the first stretchable portion is formed from the first metal for the gate electrode and gate line, and the second stretchable portion is formed from the second metal for the drain and source and data line.

36. The flexible display of claim 34, wherein the first stretchable portion and the second stretchable portion are connected at least one location outside the TFT area.