Organic electroluminescent device using optical resonance effect

• US 20040056590A1
• Filed: 09/17/2003
• Published: 03/25/2004
• Est. Priority Date: 09/18/2002
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung NEC Mobile Display Company Limited (Samsung Electronics Co. Ltd.)
• Inventors: Nam, Wi Jin, Lim, Jung Ku
• Granted Patent: US 7,098,590 B2
• Time in Patent Office: Days
• US Class Current: 313/506
• CPC Class Codes: H10K 50/852 comprising a resonant cavity structure, e.g. Bragg reflector pair
• CPC Class Codes: H10K 59/17 Passive-matrix OLED displays
• CPC Class Codes: H10K 59/173 comprising banks or shadow masks

Abstract

An organic electroluminescent device induces optical resonance with a simple structure, the organic electroluminescent device including: a transparent substrate; a semi-transparent layer formed on the transparent substrate; a first anode layer formed on the semi-transparent layer as a predetermined pattern; a cathode layer formed of a metallic total reflection layer on the first anode layer; and an organic layer formed between the first anode layer and the cathode layer, which includes at least an emitting layer, wherein the optical distance between the top surface of the semi-transparent layer and the bottom of the cathode layer is determined to be a least integer multiple of half bandwidths of peak wavelengths of light of various colors. Due to a resonance effect of the organic electroluminescent device, the emission efficiency of wavelengths of light of different colors is improved, and high-purity quality pictures may be displayed on the organic electroluminescent device.

Claims

1. An organic electroluminescent device comprising:

a transparent substrate;

a semi-transparent layer formed on the transparent substrate;

a first anode layer formed on the semi-transparent layer as a predetermined pattern;

a cathode layer formed of a metallic total reflection layer on the first anode layer; and

an organic layer formed between the first anode layer and the cathode layer, which includes at least an emitting layer,

wherein an optical distance between a top surface of the semi-transparent layer and a bottom of the cathode layer is determined to be a least integer multiple of half the peak wavelengths of light of a predetermined set of colors.

2. The organic electroluminescent device of claim 1, wherein the optical distance between the top surface of the semi-transparent layer and the bottom of the cathode layer is a sum of products of refractive indices and thicknesses of the respective first anode layer and the organic layer.

3. The organic electroluminescent device of claim 1, further comprising a transparent spacer layer between the semi-transparent layer and the first anode layer.

4. The organic electroluminescent device of claim 3, wherein the optical distance between the top surface of the semi-transparent layer and the bottom of the cathode layer is a sum of products of refractive indices and thicknesses of the respective transparent spacer layer, the first anode layer, and the organic layer.

5. The organic electroluminescent device of claim 1, further comprising a second anode layer between the transparent substrate and the semi-transparent layer.

6. The organic electroluminescent device of claim 5, wherein the optical distance between the top surface of the semi-transparent layer and the bottom of the cathode layer is a sum of products of refractive indices and thicknesses of the respective first anode layer and the organic layer.

7. The organic electroluminescent device of claim 1, further comprising a metal oxide layer deposited on the top surface of the transparent substrate.

8. The organic electroluminescent device of claim 3, further comprising a metal oxide layer deposited on the top surface of the transparent substrate.

9. The organic electroluminescent device of claim 5, further comprising a metal oxide layer deposited on the top surface of the transparent substrate.

10. The organic electroluminescent device of claim 7, wherein the metal oxide layer is one selected from the group consisting of a SiO₂ layer, a TiO₂ layer, a Y₂O₃ layer, and a Nb₂O₅ layer.

11. The organic electroluminescent device of claim 8, wherein the metal oxide layer is one selected from the group consisting of a SiO₂ layer, a TiO₂ layer, a Y₂O₃ layer, and a Nb₂O₅ layer.

12. The organic electroluminescent device of claim 9, wherein the metal oxide layer is one selected from the group consisting of a SiO₂ layer, a TiO₂ layer, a Y₂O₃ layer, and a Nb₂O₅ layer.

13. The organic electroluminescent device of claim 1, wherein the transparent substrate is a glass substrate.

14. The organic electroluminescent device of claim 1, wherein the semi-transparent layer is a thin metal layer.

15. The organic electroluminescent device of claim 14, wherein the thin metal layer is formed of one of silver and aluminum.

16. The organic electroluminescent device of claim 14, wherein the thin metal layer is formed of one of a silver-copper-gold alloy and a silver-palladium-copper alloy.

17. The organic electroluminescent device of claim 1, wherein the first anode layer and the organic layer are formed as a stripe pattern, and the cathode layer is formed as a stripe pattern perpendicular to the stripe pattern of the first anode layer and the organic layer.

18. The organic electroluminescent device of claim 1, wherein the first anode layer is formed as a stripe pattern, and the organic layer and the cathode layer are formed as a stripe pattern perpendicular to the stripe pattern of the first anode layer.

19. The organic electroluminescent device of claim 1, wherein the semi-transparent layer, the first anode layer, and the organic layer are formed as a stripe pattern, and the cathode layer is formed as a stripe pattern perpendicular to the stripe pattern of the semi-transparent layer, the first anode layer, and the organic layer.

20. The organic electroluminescent device of claim 1, wherein the semi-transparent layer and the first anode layer are formed as a stripe pattern, and the organic layer and the cathode layer are formed as a stripe pattern perpendicular to the stripe pattern of the semi-transparent layer and the first anode layer.

21. The organic electroluminescent device of claim 3, wherein the semi-transparent layer, the transparent spacer layer, the first anode layer, and the organic layer are formed as a stripe pattern, and the cathode layer is formed as a stripe pattern perpendicular to the stripe pattern of the semi-transparent layer, the transparent spacer layer, the first anode layer, and the organic layer.

22. The organic electroluminescent device of claim 3, wherein the semi-transparent layer, the transparent spacer layer, and the first anode layer are formed as a stripe pattern, and the organic layer and the cathode layer are formed as a stripe pattern perpendicular to the stripe pattern of the semi-transparent layer, the transparent spacer layer, and the first anode layer.

23. The organic electroluminescent device of claim 5, wherein the second anode layer, the semi-transparent layer, the first anode layer, and the organic layer are formed as a stripe pattern, and the cathode layer is formed as a stripe pattern perpendicular to the stripe pattern of the second anode layer, the semi-transparent layer, the first anode layer, and the organic layer.

24. The organic electroluminescent device of claim 5, wherein the second anode layer, the semi-transparent layer, and the first anode layer are formed as a stripe pattern, and the organic layer and the cathode layer are formed as a stripe pattern perpendicular to the stripe pattern of the second anode layer, the semi-transparent layer, and the first anode layer.