Efficient white-light OLED display with filters

• US 7,332,860 B2
• Filed: 03/30/2006
• Issued: 02/19/2008
• Est. Priority Date: 03/30/2006
• Status: Active Grant

• Current Assignee: Global OLED Technology LLC (LG Display Co., Ltd.)
• Original Assignee: Eastman Kodak Company
• Inventors: Spindler, Jeffrey P., Hatwar, Tukaram K.
• Primary Examiner(s): Santiago; Mariceli
• Assistant Examiner(s): DIAZ, JOSE
• Application Number:
  US11/393,767
• Publication Number:
  US 20070228938A1
• Time in Patent Office: 691 Days
• Field of Search: 313498-512, 315/169.1, 315/169.3, 428690-691, 428/917, 438 26- 29, 438/34, 438/82, 257/40, 257/72, 257 98-100, 257642-643, 257/759, 427/66, 427532-535, 427/539
• US Class Current: 313/504
• CPC Class Codes: H10K 50/125 specially adapted for multicolour light emission, e.g. for emitting white light
• CPC Class Codes: H10K 50/19 Tandem OLEDs
• CPC Class Codes: H10K 59/12 Active-matrix OLED [AMOLED] displays
• CPC Class Codes: H10K 59/351 comprising more than three subpixels, e.g. red-green-blue-white [RGBW]
• CPC Class Codes: H10K 85/322 comprising boron
• CPC Class Codes: H10K 85/621 Aromatic anhydride or imide compounds, e.g. perylene tetra-carboxylic dianhydride or perylene tetracarboxylic di-imide
• CPC Class Codes: H10K 85/622 containing four rings, e.g. pyrene
• CPC Class Codes: H10K 85/657 Polycyclic condensed heteroaromatic hydrocarbons
• CPC Class Codes: H10K 85/6572 comprising only nitrogen in the heteroaromatic polycondensed ring system, e.g. phenanthroline or carbazole
• CPC Class Codes: H10K 85/6574 comprising only oxygen in the heteroaromatic polycondensed ring system, e.g. cumarine dyes

Abstract

A white light-emitting OLED device comprising: an anode and a cathode; at least four light-emitting layers provided between the anode and the cathode, wherein each of the four light-emitting layers produces a different emission spectrum when current passes between the anode and cathode, and such spectra combine to form white light; and wherein the four light-emitting layers include a red light-emitting layer, a yellow light-emitting layer, a blue light-emitting layer, and a green light-emitting layer, arranged such that: i) each of the light-emitting layers is in contact with at least one other light-emitting layer, ii) the blue light-emitting layer is in contact with the green light-emitting layer, and iii) the red light-emitting layer is in contact with only one other light-emitting layer.

Claims

1. A white light-emitting OLED device comprising:

a) an anode and a cathode;

b) at least four light-emitting layers provided between the anode and the cathode, wherein each of the four light-emitting layers produces a different emission spectrum when current passes between the anode and cathode, and such spectra combine to form white light; and

c) wherein the four light-emitting layers include a red light-emitting layer, a yellow light-emitting layer, a blue light-emitting layer, and a green light-emitting layer, arranged such that;

i) each of the light-emitting layers is in contact with at least one other light-emitting layer,

ii) the blue light-emitting layer is in contact with the green light-emitting layer, and

iii) the red light-emitting layer is in contact with only one other light-emitting layer.

2. The white light-emitting OLED device of claim 1 wherein the red light-emitting layer is formed closest to the anode, the yellow light-emitting layer has a thickness greater than 0.5 nm and less than 5 nm and is in contact with the red light-emitting layer, the blue light-emitting layer is in contact with the yellow light-emitting layer, and the green light-emitting layer is in contact with the blue light-emitting layer.

3. The white light-emitting OLED device of claim 1 wherein the red light-emitting layer is formed closest to the anode, the yellow light-emitting layer has a thickness greater than 0.5 nm and less than 5 nm and is in contact with the red light-emitting layer, the green light-emitting layer has a thickness greater than 0.5 nm and less than 20 nm and is in contact with the yellow light-emitting layer, and the blue light-emitting layer is in contact with the green light-emitting layer.

4. The white light-emitting OLED device of claim 1 wherein the red light-emitting layer is formed closest to the anode, the blue light-emitting layer is in contact with the red light-emitting layer, the green light-emitting layer has a thickness greater than 0.5 nm and less than 20 nm and is in contact with the blue light-emitting layer, and the yellow light-emitting layer is in contact with the green light-emitting layer.

5. The white light-emitting OLED device of claim 1 wherein the red light-emitting layer is formed closest to the anode, the green light-emitting layer has a thickness greater than 0.5 nm and less than 20 nm and is in contact with the red light-emitting layer, the blue light-emitting layer is in contact with the green light-emitting layer, and the yellow light-emitting layer is in contact with the blue light-emitting layer.

6. The white light-emitting OLED device of claim 1 wherein the yellow light-emitting layer is formed closest to the anode, the blue light-emitting layer is in contact with the yellow light-emitting layer, the green light-emitting layer has a thickness greater than 0.5 nm and less than 20 nm and is in contact with the blue light-emitting layer, and the red light-emitting layer is in contact with the green light-emitting layer.

7. The white light-emitting OLED device of claim 1 wherein the yellow light-emitting layer is formed closest to the anode, the green light-emitting layer has a thickness greater than 0.5 nm and less than 20 nm and is in contact with the yellow light-emitting layer, the blue light-emitting layer is in contact with the green light-emitting layer, and the red light-emitting layer is in contact with the blue light-emitting layer.

8. The white light-emitting OLED device of claim 1 wherein the green light-emitting layer is formed closest to the anode, the blue light-emitting layer is in contact with the green light-emitting layer, the yellow light-emitting layer has a thickness greater than 0.5 nm and less than 5 nm and is in contact with the blue light-emitting layer, and the red light-emitting layer is in contact with the yellow light-emitting layer.

9. The white light-emitting OLED device of claim 1 wherein the blue light-emitting layer is formed closest to the anode, the green light-emitting layer has a thickness greater than 0.5 nm and less than 20 nm and is in contact with the blue light-emitting layer, the yellow light-emitting layer has a thickness greater than 0.5 nm and less than 5 nm and is in contact with the green light-emitting layer, and the red light-emitting layer is in contact with the yellow light-emitting layer.

29. The white light-emitting OLED device of claim 1 wherein each of the four light emitting layers includes an anthracene derivative.

30. The white light emitting OLED device of claim 29 wherein the anthracene derivative in the four light emitting layers is a monoanthracene derivative.

10. A white light-emitting OLED display comprising:

a) an array of first, second, third, and fourth light-emitting pixels, each pixel having an anode, a cathode, and at least four light-emitting layers provided between the anode and the cathode, wherein each of the four light-emitting layers produces a different emission spectrum when current passes between the anode and cathode;

b) wherein the four light-emitting layers include a red light-emitting layer, a yellow light-emitting layer, a blue light-emitting layer, and a green light-emitting layer, arranged such that;

i) each of the light-emitting layers is in contact with at least one other light-emitting layer,

ii) the blue light-emitting layer is in contact with the green light-emitting layer, and

iii) the red light-emitting layer is in contact with only one other light-emitting layer; and

c) an array of at least three different color filters in operative association with the first, second, and third light-emitting pixels, such filters being selected to receive white light to produce different colored light.

11. The white light-emitting OLED device of claim 10 wherein the red light-emitting layer is formed closest to the anode, the yellow light-emitting layer has a thickness greater than 0.5 nm and less than 5 nm and is in contact with the red light-emitting layer, the blue light-emitting layer is in contact with the yellow light-emitting layer, and the green light-emitting layer is in contact with the blue light-emitting layer.

12. The white light-emitting OLED device of claim 10 wherein the red light-emitting layer is formed closest to the anode, the yellow light-emitting layer has a thickness greater than 0.5 nm and less than 5 nm and is in contact with the red light-emitting layer, the green light-emitting layer has a thickness greater than 0.5 nm and less than 20 nm and is in contact with the yellow light-emitting layer, and the blue light-emitting layer is in contact with the green light-emitting layer.

13. The white light-emitting OLED device of claim 10 wherein the red light-emitting layer is formed closest to the anode, the blue light-emitting layer is in contact with the red light-emitting layer, the green light-emitting layer has a thickness greater than 0.5 nm and less than 20 nm and is in contact with the blue light-emitting layer, and the yellow light-emitting layer is in contact with the green light-emitting layer.

14. The white light-emitting OLED device of claim 10 wherein the red light-emitting layer is formed closest to the anode, the green light-emitting layer has a thickness greater than 0.5 nm and less than 20 nm and is in contact with the red light-emitting layer, the blue light-emitting layer is in contact with the green light-emitting layer, and the yellow light-emitting layer is in contact with the blue light-emitting layer.

15. The white light-emitting OLED device of claim 10 wherein the yellow light-emitting layer is formed closest to the anode, the blue light-emitting layer is in contact with the yellow light-emitting layer, the green light-emitting layer has a thickness greater than 0.5 nm and less than 20 nm and is in contact with the blue light-emitting layer, and the red light-emitting layer is in contact with the green light-emitting layer.

16. The white light-emitting OLED device of claim 10 wherein the yellow light-emitting layer is formed closest to the anode, the green light-emitting layer has a thickness greater than 0.5 nm and less than 20 nm and is in contact with the yellow light-emitting layer, the blue light-emitting layer is in contact with the green light-emitting layer, and the red light-emitting layer is in contact with the blue light-emitting layer.

17. The white light-emitting OLED device of claim 10 wherein the green light-emitting layer is formed closest to the anode, the blue light-emitting layer is in contact with the green light-emitting layer, the yellow light-emitting layer has a thickness greater than 0.5 nm and less than 5 nm and is in contact with the blue light-emitting layer, and the red light-emitting layer is in contact with the yellow light-emitting layer.

18. The white light-emitting OLED device of claim 10 wherein the blue light-emitting layer is formed closest to the anode, the green light-emitting layer has a thickness greater than 0.5 nm and less than 20 nm and is in contact with the blue light-emitting layer, the yellow light-emitting layer has a thickness greater than 0.5 nm and less than 5 nm and is in contact with the green light-emitting layer, and the red light-emitting layer is in contact with the yellow light-emitting layer.

19. The white light-emitting OLED display of claim 10 wherein all the pixels of the array share a common cathode.

20. A tandem white light-emitting OLED device comprising:

a) a spaced anode and cathode;

b) at least two white light-emitting units that are disposed between the electrodes and that produce emission spectra corresponding to white light and each white light-emitting unit having four light-emitting layers including a red light-emitting layer, a yellow light-emitting layer, a blue light-emitting layer, and a green light-emitting layer, arranged such that;

i) each of the light-emitting layers of a white light-emitting unit is in contact with at least one other light-emitting layer of that unit,

ii) the blue light-emitting layer of a white light-emitting unit is in contact with the green light-emitting layer of that unit, and

iii) the red light-emitting layer of a white light-emitting unit is in contact with only one other light-emitting layer of that unit; and

c) an intermediate connector disposed between the white light-emitting units.

21. The tandem white light-emitting OLED device of claim 20 wherein at least one of the white light-emitting units has the structure comprising:

the red light-emitting layer being formed closest to the anode, the yellow light-emitting layer having a thickness greater than 0.5 nm and less than 5 nm and being in contact with the red light-emitting layer, the blue light-emitting layer being in contact with the yellow light-emitting layer, and the green light-emitting layer being in contact with the blue light-emitting layer.

22. The tandem white light-emitting OLED device of claim 20 wherein at least one of the white light-emitting units has the structure comprising:

the red light-emitting layer being formed closest to the anode, the yellow light-emitting layer having a thickness greater than 0.5 nm and less than 5 nm and being in contact with the red light-emitting layer, the green light-emitting layer having a thickness greater than 0.5 nm and less than 20 nm and being in contact with the yellow light-emitting layer, and the blue light-emitting layer being in contact with the green light-emitting layer.

23. The tandem white light-emitting OLED device of claim 20 wherein at least one of the white light-emitting units has the structure comprising:

the red light-emitting layer being formed closest to the anode, the blue light-emitting layer being in contact with the red light-emitting layer, the green light-emitting layer having a thickness greater than 0.5 nm and less than 20 nm and being in contact with the blue light-emitting layer, and the yellow light-emitting layer being in contact with the green light-emitting layer.

24. The tandem white light-emitting OLED device of claim 20 wherein at least one of the white light-emitting units has the structure comprising:

the red light-emitting layer being formed closest to the anode, the green light-emitting layer having a thickness greater than 0.5 nm and less than 20 nm and being in contact with the red light-emitting layer, the blue light-emitting layer being in contact with the green light-emitting layer, and the yellow light-emitting layer being in contact with the blue light-emitting layer.

25. The tandem white light-emitting OLED device of claim 20 wherein at least one of the white light-emitting units has the structure comprising:

the yellow light-emitting layer being formed closest to the anode, the blue light-emitting layer being in contact with the yellow light-emitting layer, the green light-emitting layer having a thickness greater than 0.5 nm and less than 20 nm and being in contact with the blue light-emitting layer, and the red light-emitting layer being in contact with the green light-emitting layer.

26. The tandem white light-emitting OLED device of claim 20 wherein at least one of the white light-emitting units has the structure comprising:

the yellow light-emitting layer being formed closest to the anode, the green light-emitting layer having a thickness greater than 0.5 nm and less than 20 nm and being in contact with the yellow light-emitting layer, the blue light-emitting layer being in contact with the green light-emitting layer, and the red light-emitting layer being in contact with the blue light-emitting layer.

27. The tandem white light-emitting OLED device of claim 20 wherein at least one of the white light-emitting units has the structure comprising:

the green light-emitting layer being formed closest to the anode, the blue light-emitting layer being in contact with the green light-emitting layer, the yellow light-emitting layer having a thickness greater than 0.5 nm and less than 5 nm and being in contact with the blue light-emitting layer, and the red light-emitting layer being in contact with the yellow light-emitting layer.

28. The tandem white light-emitting OLED device of claim 20 wherein at least one of the white light-emitting units has the structure comprising:

the blue light-emitting layer being formed closest to the anode, the green light-emitting layer having a thickness greater than 0.5 nm and less than 20 nm and being in contact with the blue light-emitting layer, the yellow light-emitting layer having a thickness greater than 0.5 nm and less than 5 nm and being in contact with the green light-emitting layer, and the red light-emitting layer being in contact with the yellow light-emitting layer.

31. The tandem white light-emitting OLED device of claim 20 wherein each of the four light emitting layers in each white light emitting unit includes an anthracene derivative.

32. The tandem white light-emitting OLED device of claim 31 wherein the anthracene derivative in each of the four light emitting layers in each white light emitting unit is a monoanthracene derivative.