Encapsulation of polymer based solid state devices with inorganic materials

• US 20040140766A1
• Filed: 01/06/2004
• Published: 07/22/2004
• Est. Priority Date: 08/03/1998
• Status: Active Grant

• Current Assignee: Boo Nilsson, Phillip Bailey
• Original Assignee: Boo Nilsson, Phillip Bailey
• Inventors: Nilsson, Boo, Bailey, Phillip
• Granted Patent: US 7,088,041 B2
• Time in Patent Office: Days
• US Class Current: 313/512
• CPC Class Codes: H05B 33/04 Sealing arrangements , e.g. against humidity
• CPC Class Codes: H10K 50/8426 Peripheral sealing arrangements, e.g. adhesives, sealants
• CPC Class Codes: H10K 50/844 Encapsulations
• CPC Class Codes: H10K 59/8722 Peripheral sealing arrangements, e.g. adhesives, sealants
• CPC Class Codes: H10K 59/873 Encapsulations

Abstract

Methods for creating a protective seal suitable for protecting polymer-based electronic devices, including light emitting diodes and polymer emissive displays, are disclosed together with the protected devices. The protective seal includes one or more thin films of silicon nitride (SiN) or other inorganic dielectric applied at low temperature. One or more nonreactive metal layers may be present in the protective layer as well. Other embodiments are disclosed which include a protective cover over the protective layers. These protective layers provide encapsulation with sufficient protection from the atmosphere to enable shelf life and stress life for polymer electronic devices that are adequate for commercial applications.

Claims

1. In a light-emitting device comprising a layer of an active light-emitting polymer sandwiched between a cathode and an anode, the improvement comprising an encapsulating layer of low-temperature-applied inorganic material protecting the device against environmental attack.

2. The device of claim 1 wherein the low-temperature-applied inorganic material comprise an oxide or nitride of a group IIIb or group IVb element.

3. The device of claim 2 wherein the inorganic material is a silicon-based material.

4. The device of claim 3 wherein the inorganic material is a silicon-based material selected from silicon-nitride and silicon-oxide.

5. The device of claim 1 additionally comprising a low-temperature-applied coating comprising a nonreactive metal located between the device and the layer of inorganic material.

6. The device of claim 1 additionally comprising a protective cover plate attached over the layer of inorganic material.

7. The device of claim 6 wherein the protective cover plate is attached with epoxy.

8. The device of claim 7 wherein the epoxy is around the perimeter of the cover.

9. The device of claim 8 additionally comprising an inert gas between the cover and the layer of inorganic material.

10. The device of claim 7 wherein the epoxy is uniformly distributed between the cover and the layer of inorganic material.

11. The device of claim 5 additionally comprising a protective cover plate attached over the layer of inorganic material.

12. The device of claim 11 wherein the protective cover plate is attached with epoxy.

13. The device of claim 12 wherein the epoxy is around the perimeter of the cover.

14. The device of claim 13 additionally comprising an inert gas between the cover and the layer of inorganic material.

15. The device of claim 12 wherein the epoxy is uniformly distributed between the cover and the layer of inorganic material.

16. The device of claim 6 wherein the protective cover plate is attached with solder.

17. The device of claim 11 wherein the protective cover plate is attached with solder.

18. The device of claim 1 wherein the coating of inorganic material is in the form of a frame plate.

19. The device of claim 1 wherein the layer of inorganic material is applied at a temperature below 400°

C.

20. The device of claim 5 wherein the nonreactive metal is applied at a temperature below 400°

C.

21. The device of claim 5 wherein both the nonreactive metal and the inorganic material are applied at a temperature below 400°

C.

22. A method for protecting a light-emitting device comprising an active light-emitting polymer sandwiched between a cathode and an anode comprising encapsulating said device with an encapsulating layer of low-temperature-applied inorganic material.

23. The method of claim 22 wherein the low-temperature-applied inorganic material comprise an oxide or nitride of a group IIIb or group IVb element.

24. The method of claim 22 additionally comprising the step of overcoating the layer of low-temperature-applied inorganic material with a layer of nonreactive metal.

25. The method of claim 22 additionally comprising the step of attaching a protective plate over the layer of inorganic material.

26. The method of claim 24 additionally comprising a low-temperature-applied coating comprising a nonreactive metal located between the device and the layer of inorganic material.