Encapsulated RGB OLEDs having enhanced optical output

• US 9,337,446 B2
• Filed: 12/22/2008
• Issued: 05/10/2016
• Est. Priority Date: 12/22/2008
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Inventors: Visser, Robert Jan, Moro, Lorenza
• Primary Examiner(s): Santiago, Mariceli
• Application Number:
  US12/341,134
• Publication Number:
  US 20100156277A1
• Time in Patent Office: 2,696 Days
• Field of Search: 313500-512
• US Class Current: 1/1
• CPC Class Codes: H10K 2102/351 Thickness
• CPC Class Codes: H10K 50/828 Transparent cathodes, e.g. comprising thin metal layers
• CPC Class Codes: H10K 50/84 Passivation; Containers; Encapsulations
• CPC Class Codes: H10K 50/844 Encapsulations
• CPC Class Codes: H10K 50/858 comprising refractive means, e.g. lenses
• CPC Class Codes: H10K 59/80524 Transparent cathodes, e.g. comprising thin metal layers
• CPC Class Codes: H10K 59/873 Encapsulations
• CPC Class Codes: H10K 59/879 comprising refractive means, e.g. lenses

Abstract

Methods of making an integrated barrier stack and optical enhancement layer for protecting and improving the light out coupling of an encapsulated OLED are described. The method includes optimizing the thickness of various layers including the initial inorganic barrier layer and the inorganic barrier layer and polymeric decoupling layer for the barrier stack. The thickness is optimized for at least one of maximum efficiency, minimum dispersion, or minimum spectral shift so that the encapsulated OLED has enhanced light outcoupling compared to the bare OLED.

Claims

1. A method of making an integrated barrier and optical enhancement stack for protecting and improving the light out coupling of an encapsulated OLED comprising;

providing an OLED having at least two colors selected from red, green, or blue, and a transparent electrode;

selecting an initial inorganic barrier layer having a refractive index in a range of about 1.55 to about 2, the initial inorganic barrier layer adjacent to the transparent electrode in the OLED;

providing a thickness of the initial inorganic barrier layer for the OLED within a range of about 40 nm to about 240 nm;

selecting a barrier stack comprising an inorganic barrier layer and a polymeric decoupling layer, the inorganic barrier layer having a refractive index in a range of about 1.55 to about 2, and the polymeric decoupling layer having a refractive index in a range of about 1.4 to about 1.65, the barrier stack adjacent to the initial inorganic barrier layer;

providing a thickness of the inorganic barrier layer within a range of about 20 nm to about 80 nm and the polymeric decoupling layer of the barrier stack within a range of about 0.2 μ

m to about 4 μ

m;

optimizing the thickness of at least one of the initial inorganic barrier layer, the inorganic barrier layer, or the polymeric decoupling layer for at least one of maximum efficiency, minimum dispersion, or minimum spectral shift, so that the encapsulated OLED has enhanced light outcoupling compared to a bare OLED, said optimizing being achieved without use of either (a) a scattering layer placed adjacent the OLED, initial inorganic barrier layer or barrier stack or (b) a quarter-wave stack placed adjacent the OLED, initial inorganic barrier layer or barrier stack;

depositing the initial inorganic barrier layer having the optimized thickness adjacent to the transparent electrode of the OLED; and

depositing the barrier stack having the optimized thickness adjacent to the initial inorganic layer.

2. The method of claim 1 further comprising:

selecting a plasma protective layer having a refractive index in a range of about 1.1 to about 1.9; and

optimizing a thickness of the plasma protective layer for the OLED within a range of about 20 nm to about 50 nm;

wherein the thickness of the plasma protective layer is optimized for at least one of maximum efficiency, minimum dispersion, or minimum spectral shift, and

wherein the plasma protective layer is positioned between the OLED and the initial inorganic barrier layer;

depositing the plasma protective layer having the optimized thickness adjacent to the transparent electrode of the OLED before the initial inorganic barrier layer is deposited.

3. The method of claim 2 wherein the plasma protective layer is an inorganic layer.

4. The method of claim 1 wherein the transparent electrode in the OLED is a transparent cathode.

5. The method of claim 4 wherein providing the OLED includes:

selecting the transparent cathode layer, the transparent cathode layer having a refractive index in a range of about 1.6 to about 2; and

optimizing a thickness of the transparent cathode layer within a range of about 20 to about 300 nm,

and wherein the thickness of the transparent cathode layer is optimized for at least one of maximum efficiency, minimum dispersion, or minimum spectral shift.

6. The method of claim 1 wherein the maximum efficiency or total efficiency is increased by at least about 20% compared to the bare OLED.

7. The method of claim 1 wherein the maximum efficiency or total efficiency is increased by at least about 40% compared to the bare OLED.

8. The method of claim 1 wherein the maximum efficiency or total efficiency is increased by at least about 50% compared to the bare OLED.

9. The method of claim 1 wherein the transparent electrode in the OLED is a transparent anode.

10. The method of claim 1 wherein the encapsulated OLED exhibits an intentional spectral shift.

20. The product made by the method of claim 1.

21. The product made by the method of claim 2.

11. A method of making an integrated barrier and optical enhancement stack for protecting and improving the light out coupling of an encapsulated OLED comprising;

providing an OLED having at least two colors selected from red, green, or blue, and a transparent electrode;

selecting a plasma protective layer having a refractive index in a range of about 1.1 to about 1.9, the plasma protective layer adjacent to the transparent electrode in the OLED;

optimizing a thickness of the plasma protective layer for the OLED within range of about 20 nm to about 50 nm;

selecting an initial inorganic barrier layer having a refractive index in a range of about 1.55 to about 2, the initial inorganic barrier layer adjacent to the plasma protective layer;

providing a thickness of the initial inorganic barrier layer for the OLED within a range of about 40 nm to about 240 nm;

selecting a barrier stack comprising an inorganic barrier layer and a polymeric decoupling layer, the inorganic barrier layer having a refractive index in a range of about 1.55 to about 2, and the polymeric decoupling layer having a refractive index in a range of about 1.4 to about 1.5, the barrier stack adjacent to the initial inorganic barrier layer;

providing a thickness of the inorganic barrier layer within a range of about 20 nm to about 80 nm and the polymeric decoupling layer of the barrier stack within a range of about 0.2 μ

m to about 4 μ

m;

optimizing the thickness of at least one of the plasma protective layer, the initial inorganic barrier layer, the inorganic barrier layer, or the polymeric decoupling layer for at least one of maximum efficiency, minimum dispersion, or minimum spectral shift so that the encapsulated OLED has enhanced light outcoupling compared to a bare OLED, said optimizing being achieved without use of either (a) a scattering layer placed adjacent the OLED, initial inorganic barrier layer or barrier stack or (b) a quarter-wave stack placed adjacent the OLED, initial inorganic barrier layer or barrier stack;

depositing the plasma protective layer having the optimized thickness adjacent to the transparent electrode of the OLED;

depositing the initial inorganic barrier layer having the optimized thickness adjacent to the plasma protective layer; and

depositing the barrier stack having the optimized thickness adjacent to the initial inorganic barrier layer.

12. The method of claim 11 wherein the transparent electrode in the OLED is a transparent cathode.

13. The method of claim 12 wherein providing the OLED includes:

selecting a transparent cathode layer material, the transparent cathode layer material having a refractive index in a range of about 1.6 to about 2; and

optimizing a thickness of the transparent cathode layer within a range of about 20 to about 300 nm,

and wherein thickness of the transparent cathode layer is optimized for at least one of maximum efficiency, minimum dispersion, or minimum spectral shift.

14. The method of claim 11 wherein the maximum efficiency or total efficiency is increased by at least about 20% compared to the bare OLED.

15. The method of claim 11 wherein the maximum efficiency or total efficiency is increased by at least about 40% compared to the bare OLED.

16. The method of claim 11 wherein the maximum efficiency or total efficiency is increased by at least about 50% compared to the bare OLED.

17. The method of claim 11 wherein the plasma protective layer is an inorganic layer.

18. The method of claim 11 wherein the transparent electrode in the OLED is a transparent anode.

19. The method of claim 11 wherein the encapsulated OLED exhibits an intentional spectral shift.

22. The product made by the method of claim 11.