OLED with minimal plasmonic losses

Patent metadata

Field	Value
Publication number	US-10770690-B2
Application number	US-201816189088-A
Country	US
Kind code	B2
Filing date	Nov 13, 2018
Priority date	Nov 15, 2017
Publication date	Sep 8, 2020
Grant date	Sep 8, 2020

Abstract

A top-emitting organic light emitting device (OLED) that comprises: a substrate having an inward side and an outward side; an OLED body that includes a transparent bottom electrode proximate to the inward side of the substrate, an organic emitting layer, and a transparent top electrode in that order; a non-metallic, diffuse reflective layer with a roughened top surface proximate to and facing the bottom transparent electrode; and a high refractive index waveguide layer. The diffuse reflective layer is positioned between the inward side of the substrate and the OLED body, and the waveguide layer is positioned between the diffuse layer and the bottom transparent electrode.

First claim

We claim:

1. A top-emitting organic light emitting device (OLED) comprising:
a substrate having an inward side and an outward side;
a non-metallic, diffuse reflective layer with a roughened top surface and a bottom surface disposed over the substrate with the roughened top surface disposed over the bottom surface;
a high refractive index waveguide layer disposed over the reflective layer; and
an OLED body disposed over the reflective layer, the OLED body comprising:
a transparent bottom electrode disposed over high refractive index waveguide layer,
an organic emissive layer disposed over the transparent bottom electrode, and
a transparent top electrode disposed over the organic emissive layer;

wherein a majority of light emitted by the OLED during operation is emitted through the transparent top electrode.

2. The OLED of claim 1 , wherein the roughened top surface of the diffuse reflective layer has a root-mean-square roughness in a range from 1.0 μm to 25 μm.

3. The OLED of claim 1 , further comprising a microlens array disposed over the top transparent electrode.

4. The OLED of claim 1 , wherein the bottom electrode is an anode and the top electrode in a cathode, and the anode and cathode are the same material.

5. The OLED of claim 1 , wherein the diffuse reflective layer is selected from polytetrafluoroethylene (PTFE), polyethylene terephthalate (PET), and barium sulfate.

6. The OLED of claim 1 , wherein the diffuse reflective layer is positioned at a distance of at least 100 nm from the organic emissive layer.

7. The OLED of claim 1 , wherein the high refractive index waveguide layer is a polymer with a refractive index in a range from 1.6 to 2.1.

8. The OLED of claim 1 , wherein the inside of the substrate is corrugated with a pattern of corrugation and the pattern of corrugation extends to the diffuse reflective layer.

9. The OLED of claim 1 , wherein the light emitted from the device top-emitting OLED has a narrow emission spectrum of less than 40 nm fwhh, and the peak emissive wavelength provides a distinct color selected from blue, green, yellow, orange, or red.

10. The OLED of claim 3 , wherein the microlens array is in direct physical contact with the top transparent electrode.

11. The OLED of claim 1 , wherein the OLED body is in direct physical contact with the waveguide layer.

12. The OLED of claim 11 , wherein the reflective layer is in direct physical contact with the substrate.

13. The OLED of claim 1 , wherein the reflective layer is in direct physical contact with the substrate and the waveguide layer.

14. The OLED of claim 1 , wherein the substrate is corrugated.

15. The OLED of claim 14 , wherein the emissive layer is corrugated with a structure caused by a structure of corrugation of the substrate.

16. The OLED of claim 14 , wherein the substrate has a random corrugated structure.

17. The OLED of claim 16 , wherein the emissive layer is corrugated with a structure caused by a structure of corrugation of the substrate.

Assignees

• Univ Michigan Regents

Inventors

• Forrest Stephen R
• Kim Jongchan

Classifications

• H10K50/856

  comprising reflective means · CPC title

• H10K59/878 Primary

  comprising reflective means · CPC title

• G02B5/0221

  the surface having an irregular structure (G02B5/0226 takes precedence) · CPC title

• G02B5/0284

  used in reflection · CPC title

• H01L2251/5315

  Electricity · mapped topic