Organic light emitting display device having a reflective barrier and method of manufacturing the same

• US 10,490,613 B2
• Filed: 11/28/2017
• Issued: 11/26/2019
• Est. Priority Date: 11/30/2016
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Display Co., Ltd.
• Inventors: Lee, Seong-Joo, Kim, Jeong-Oh, Beak, Jung-Sun
• Primary Examiner(s): Bradley, Stephen M
• Application Number:
  US15/824,715
• Publication Number:
  US 20180151645A1
• Time in Patent Office: 728 Days
• CPC Class Codes: H10K 50/856 comprising reflective means
• CPC Class Codes: H10K 59/12 Active-matrix OLED [AMOLED] displays
• CPC Class Codes: H10K 59/123 Connection of the pixel electrodes to the thin film transistors [TFT]
• CPC Class Codes: H10K 71/00 Manufacture or treatment specially adapted for the organic devices covered by this subclass

Abstract

Disclosed are an organic light emitting display device to improve optical efficiency and prevent deterioration in reliability of thin film transistors, and a method of manufacturing the same. The organic light emitting display device includes a mirror wall which is disposed on a substrate such that the mirror wall surrounds a light emitting area of each sub-pixel where a light emitting element is disposed, thus preventing total reflection of light produced in the light emitting element and improving optical efficiency by reflecting light travelling toward a non-emitting area to be directed to the light emitting area.

Claims

1. An organic light emitting display device comprising:

a substrate;

a plurality of sub-pixels on the substrate, each of the sub-pixels including;

a light emitting element disposed in a light emitting area; and

a pixel circuit disposed in a circuit area, the pixel circuit configured to operate the light emitting element; and

a reflective barrier disposed overlying the substrate and surrounding a perimeter of the light emitting area of each sub-pixel, the reflective barrier including;

an insulation layer surrounding the perimeter of the light emitting area of each sub-pixel, the insulation layer having an upper surface, an inner sidewall facing the light emitting area of the sub-pixels, and an outer sidewall opposite the inner sidewall; and

a reflective layer disposed on the upper surface, the inner sidewall, and the outer sidewall of the insulation layer.

2. The organic light emitting display device according to claim 1, further comprising:

a transparent layer disposed between the insulation layer and the reflective layer.

3. The organic light emitting display device according to claim 2, further comprising:

a color filter disposed between the substrate and the light emitting element; and

a planarization layer on the color filter,

wherein the insulation layer and the planarization layer are formed of a same material and are disposed on a same plane, and

the transparent layer and an anode of the light emitting element are formed of a same material and are disposed on a same plane.

4. The organic light emitting display device according to claim 1, wherein the reflective barrier surrounds

a perimeter of the circuit area of each sub-pixel.

5. The organic light emitting display device according to claim 4, further comprising:

a transparent layer disposed between the insulation layer and the reflective layer.

6. The organic light emitting display device according to claim 4, wherein the insulation layer includes portions that extend between the light emitting area and the circuit area of each sub-pixel.

7. The organic light emitting display device according to claim 5, further comprising:

a color filter disposed between the substrate and the light emitting element; and

a planarization layer on the color filter,

wherein the insulation layer and the planarization layer are formed of a same material and are disposed on a same plane, and

the transparent layer and an anode of the light emitting element are formed of a same material and are disposed on a same plane.

8. The organic light emitting display device according to claim 1, wherein the reflective layer is formed using a same material as a cathode of the light emitting element.

9. The organic light emitting display device according to claim 1, wherein the reflective layer is formed as a single layer or multiple layers including at least one of molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), copper (Cu) and APC (Ag;

Pb;

Cu), or an alloy thereof.

10. The organic light emitting display device according claim 1, wherein the pixel circuit comprises:

a driving transistor connected to the light emitting element; and

a switching transistor connected to the driving transistor,

wherein the reflective barrier is disposed between the light emitting area and the circuit area.

11. The organic light emitting display device according to claim 10, further comprising:

a scan line connected to a gate electrode of the switching transistor;

a data line connected to a source electrode of the switching transistor; and

a high-voltage supply line connected to a source electrode of the driving transistor,

wherein the reflective barrier overlaps with the scan line, the data line and the high-voltage supply line.

12. The organic light emitting display device according to claim 11, wherein the reflective layer overlapping with the scan line, the data line and the high-voltage supply line is spaced apart from an anode of the light emitting element.

13. The organic light emitting display device according to claim 10, wherein the light emitting element comprises:

an anode connected to the driving transistor;

a cathode facing the anode; and

a light emitting stack disposed between the anode and the cathode,

wherein an upper surface of the reflective layer disposed on the insulation layer is disposed on a higher plane relative to the substrate than a lower surface of the light emitting stack contacting the anode.

14. The organic light emitting display device according to claim 13, wherein the reflective layer and the cathode reflect light produced in the light emitting stack toward the substrate.

15. The organic light emitting display device according to claim 1, wherein the reflective layer completely covers the upper surface of the insulation layer.

16. The organic light emitting display device according to claim 1, wherein the reflective layer partially covers the upper surface of the insulation layer, a portion of the upper surface of the insulation layer being uncovered by the reflective layer.

17. The organic light emitting display device according to claim 1, further comprising:

a data line electrically coupled to the pixel circuit and disposed adjacent to a first side of the light emitting area; and

a high-voltage supply line electrically coupled to the pixel circuit and disposed adjacent to a second side of the light emitting area that is opposite the first side,

wherein the insulation layer of the reflective barrier is disposed on the data line and the high-voltage supply line, and portions of the upper surface of the insulation layer overlapping the data line and the high-voltage supply line are uncovered by the reflective layer.

18. The organic light emitting display device according to claim 1, wherein the reflective layer extends continuously between a first portion on the upper surface of the insulation layer and a second portion on the inner sidewall of the insulation layer.

19. A method of manufacturing an organic light emitting display device comprising:

forming a pixel circuit in a pixel area of a sub-pixel on a substrate;

forming a light emitting element in a light emitting area of the sub-pixel; and

forming a reflective barrier on the substrate, the forming the reflective barrier including;

forming an insulation layer surrounding a perimeter of the light emitting area, the insulation layer having an upper surface, an inner sidewall facing the light emitting area of the sub-pixels, and an outer sidewall opposite the inner sidewalls; and

forming a reflective layer on the upper surface, the inner sidewall, and the outer sidewall of the insulation laver.

20. The method of claim 19, wherein forming the reflective layer includes forming the reflective layer to have an upper surface disposed at a height from a surface of the substrate that is greater than a height of an anode of the light emitting element from the surface of the substrate.

21. The method of claim 19, wherein forming the pixel circuit includes:

forming a driving transistor connected to the light emitting element; and

forming a switching transistor connected to the driving transistor.

22. The method of claim 21 wherein forming the reflective barrier includes:

forming at least a portion of the reflective barrier between the light emitting area and the pixel circuit area.