Apparatus and method for encapsulating an OLED formed on a flexible substrate

• US 20040201027A1
• Filed: 04/11/2003
• Published: 10/14/2004
• Est. Priority Date: 04/11/2003
• Status: Active Grant

• Current Assignee: Global OLED Technology LLC (LG Display Co., Ltd.)
• Original Assignee: Eastman Kodak Company
• Inventors: Ghosh, Amalkumar P.
• Granted Patent: US 6,888,172 B2
• Time in Patent Office: Days
• US Class Current: 257/99
• CPC Class Codes: H10K 2102/3026 Top emission
• CPC Class Codes: H10K 2102/311 Flexible OLED
• CPC Class Codes: H10K 50/844 Encapsulations
• CPC Class Codes: H10K 59/873 Encapsulations

Abstract

An apparatus and method are disclosed for encapsulating an OLED device formed on a flexible substrate. The OLED device is moisture protected by an encapsulation which sandwiches the OLED device between two transparent dielectric metal oxide layers. The oxide layers are formed in a chamber which includes a plurality of processing stations for forming successive atomic layers of oxides along passes of the flexible substrate within the chamber.

Claims

1. A method of forming a transparent moisture barrier layer in direct contact with a flexible substrate on which can be formed an OLED device, comprising the steps of:

a) providing a vacuum chamber;

b) disposing within the vacuum chamber a repeating series of stations including at least two spaced apart processing stations and an intermediate purging station disposed between the two processing stations and wherein the two processing stations include different gases which react with the substrate to form a portion of the moisture barrier layer, the purging station having a purging gas disposed between the processing stations and directed to impinge upon the substrate to separate the two different gases in the processing stations; and

c) moving the flexible substrate along a path in the vacuum chamber past the repeating stations which form the moisture barrier layer on the substrate.

2. The method of claim 1 further including repeating steps b) and c) in the same or a different vacuum chamber to form a transparent moisture protective encapsulation layer over the OLED device and over the moisture barrier layer.

3. The method of claim 1 wherein the gases in the processing stations include ozone, trimethylaluminum, and nitrogen.

4. The method of claim 1 wherein the gases form a transparent dielectric oxide layer.

5. The method of claim 4 wherein the transparent dielectric oxide layer includes aluminum oxide, silicon dioxide, aluminum titanium oxide, tantalum oxide, hafnium oxide, or zirconium oxide.

6. The method of claim 2 further including providing openings through the encapsulation layer to permit electrical connections to the OLED device.

7. Apparatus for forming a transparent moisture barrier layer in direct contact with a flexible substrate on which can be formed an OLED device in a vacuum chamber, comprising:

a) a repeating series of stations including at least two spaced apart processing stations and an intermediate purging station disposed within the vacuum chamber between the two processing stations and wherein the two processing stations include different gases which react with the substrate to form a portion of the moisture barrier layer, the purging station having a purging gas disposed between the processing stations and directed to impinge upon the substrate to separate the two different gases in the processing stations;

b) means for moving the flexible substrate along a path in the vacuum chamber past the repeating stations; and

c) means for controlling the operation of the repeating series of stations to form the moisture barrier layer on the substrate.

8. The apparatus of claim 7 wherein the processing stations and the intermediate purging station are disposed in the same or a different vacuum chamber to form a transparent moisture protective encapsulation layer over the OLED device and over the moisture barrier layer.

9. The apparatus of claim 7 wherein the gases in the processing stations include ozone, trimethylaluminum, and nitrogen.

10. The apparatus of claim 7 wherein the gases form a transparent dielectric oxide layer.

11. The apparatus of claim 10 wherein the transparent dielectric oxide layer includes aluminum oxide, silicon dioxide, aluminum titanium oxide, tantalum oxide, hafnium oxide, or zirconium oxide.

12. A moisture protected OLED device, comprising:

a) a flexible substrate;

b) a transparent moisture barrier layer in direct contact with one surface of the substrate;

c) a first electrode layer formed over at least a portion of the moisture barrier layer;

d) an organic electroluminescent medium structure formed over at least a portion of the first electrode layer;

e) a second electrode layer formed over at least a portion of the electroluminescent medium structure;

f) a transparent moisture protective encapsulation layer formed over the second electrode layer and extending over a portion of the moisture barrier layer; and

g) openings formed through the encapsulation layer to permit electrical connections to the first and second electrode layers of the OLED device.

13. The moisture protected OLED device of claim 12 wherein the moisture barrier layer and the moisture protective encapsulation layer are formed of transparent dielectric metal oxides.

14. The moisture protected OLED device of claim 13 wherein the transparent dielectric materials include aluminum oxide, silicon dioxide, aluminum titanium oxide, tantalum oxide, hafnium oxide, or zirconium oxide.