OLEDs having light absorbing electrode

• US 6,750,609 B2
• Filed: 08/22/2001
• Issued: 06/15/2004
• Est. Priority Date: 08/22/2001
• Status: Expired due to Term

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: Xerox Corporation (Xerox Holdings Corp.)
• Inventors: Duff, James M., Hu, Nan-Xing, Aziz, Hany, Popovic, Zoran D.
• Primary Examiner(s): Patel, Vip
• Application Number:
  US09/935,031
• Publication Number:
  US 20030038593A1
• Time in Patent Office: 1,028 Days
• Field of Search: 313/504, 313/506, 313/311, 313/5.3, 313/512
• US Class Current: 313/506
• CPC Class Codes: H10K 50/86 Arrangements for improving contrast, e.g. preventing reflection of ambient light
• CPC Class Codes: H10K 59/8791 Arrangements for improving contrast, e.g. preventing reflection of ambient light

Abstract

An organic light emitting device composed of: a first electrode; a second electrode; and a luminescent region including an organic electroluminescent material between the first electrode and the second electrode, wherein one of the first electrode and the second electrode includes both a substantially transparent charge injecting layer adjacent to the luminescent region and an electrically conductive light absorbing layer.

Claims

1. An organic light emitting device defining a viewer side and comprising:

a first electrode;

a second electrode; and

a luminescent region including an organic electroluminescent material between the first electrode and the second electrode, wherein one of the first electrode and the second electrode includes both a single substantially transparent charge injecting layer adjacent to the luminescent region and an electrically conductive light absorbing layer wherein the light absorbing layer is positioned farther from the viewer side than the luminescent region and the light absorbing layer overlays the charge injecting layer to absorb ambient light that passes through the charge injecting layer.

2. The device of claim 1, further comprising a substrate, wherein one of the first electrode and the second electrode is between the substrate and the luminescent region.

3. The device of claim 1, wherein the charge injecting layer has a thickness ranging from about 10 Angstroms to about 50,000 Angstroms.

4. The device of claim 1, wherein the light absorbing layer is deposited by thermal evaporation in vacuum.

5. The device of claim 1, wherein the light absorbing layer exhibits at least about 50% extinction of light entering the light absorbing layer.

6. The device of claim 1, wherein the light absorbing layer exhibits at least about 90% extinction of light entering the light absorbing layer.

7. An organic light emitting device defining a viewer side and comprising in sequence:

(a) a cathode including;

(i) an electrically conductive light absorbing layer, and

(ii) a single substantially transparent electron injecting layer;

(b) a luminescent region including an organic electroluminescent material; and

(c) an anode that is substantially transparent to light wherein the light absorbing layer is positioned farther from the viewer side than the luminescent region and the light absorbing layer overlays the electron injecting layer to absorb ambient light that passes through the electron injecting layer.

8. The device of claim 7, further comprising a substantially transparent substrate, wherein the anode is between the luminescent region and the substrate.

9. The device of claim 7, further comprising a substrate, wherein the cathode is between the luminescent region and the substrate.

10. The device of claim 7, wherein the cathode further comprises a metallic layer, wherein the light absorbing layer is between the metallic layer and the electron injecting layer.

11. The device of claim 7, wherein the cathode further comprises a buffer layer between the light absorbing layer and the electron injecting layer.

12. The device of claim 7, wherein the electron injecting layer has a thickness ranging from about 10 Angstroms to about 50,000 Angstroms.

13. The device of claim 7 wherein the light absorbing layer is deposited by thermal evaporation in vacuum.

14. The device of claim 7, wherein the light absorbing layer exhibits at least about 50% extinction of light entering the light absorbing layer.

15. The device of claim 7, wherein the light absorbing layer exhibits at least about 90% extinction of light entering the light absorbing layer.

16. An organic light emitting device defining a viewer side and comprising in sequence:

(a) a cathode that is substantially transparent to light;

(b) a luminescent region including an organic electroluminescent material; and

(c) an anode including;

(i) a substantially transparent hole injecting layer, and

(ii) an electrically conductive light absorbing layer wherein the light absorbing layer is positioned farther from the viewer side than the luminescent region and the light absorbing layer overlays the hole injecting layer to absorb ambient light that passes through the hole injecting layer.