Color OLED device having improved performance

• US 7,091,523 B2
• Filed: 05/13/2004
• Issued: 08/15/2006
• Est. Priority Date: 05/13/2004
• Status: Active Grant

• Current Assignee: Global OLED Technology LLC (LG Display Co., Ltd.)
• Original Assignee: Eastman Kodak Company
• Inventors: Miller, Michael E., Cok, Ronald S.
• Primary Examiner(s): Weiss, Howard
• Assistant Examiner(s): Trinh, (Vikki) Hoa B.
• Application Number:
  US10/845,038
• Publication Number:
  US 20050258429A1
• Time in Patent Office: 824 Days
• Field of Search: 257/98, 257/103, 257/89, 257/79, 315/169.3, 313/500, 313/504, 313/506, 313/113, 345/589
• US Class Current: 257/79
• CPC Class Codes: H10K 59/351 comprising more than three subpixels, e.g. red-green-blue-white [RGBW]
• CPC Class Codes: H10K 59/38 comprising colour filters or colour changing media [CCM]

Abstract

A color OLED device is described having one or more pixels, at least one pixel comprising: four or more light-emitting elements, each light-emitting element comprising one or more layers of electroluminescent organic material producing a broadband light having a variable frequency-dependent luminous efficacy emission spectrum, and each light-emitting element further comprising a filter for filtering the broadband light and emitting a different color of light; wherein the different colors of light emitted by three of the light-emitting elements specify a first color gamut of the OLED device, and an additional one or more of the light-emitting elements emit at least one additional different color of light and wherein the frequency range of the filter of the additional light emitting element is matched to a portion of the broadband light frequency range having a radiant intensity greater than the radiant intensity of the frequency range of at least one of the filters of the three light-emitting elements specifying the first color gamut of the OLED device, and the additional one or more light emitting elements having luminous efficiency greater than that of at least one of the three light emitting elements specifying the first color gamut.

Claims

1. A color OLED device having one or more pixels, at least one pixel comprising:

four or more light-emitting elements, each light-emitting element comprising one or more layers of electroluminescent organic material producing a broadband light having a variable frequency-dependent luminous efficacy emission spectrum, and each light-emitting element further comprising a different color filter having a frequency range matched to a portion of the broadband light frequency range for differentially filtering the broadband light and emitting a different color of light;

wherein the different colors of light emitted by three of the light-emitting elements specify a first color gamut of the OLED device, and an additional one or more of the light-emitting elements emit at least one additional different color of light and wherein the frequency range of the color filter of the additional light emitting element is matched to a portion of the broadband light frequency range having a radiant intensity greater than the radiant intensity of the portion of the broadband light frequency range that is matched to the frequency range of at least one of the color filters of the three light-emitting elements specifying the first color gamut of the OLED device, and the additional one or more light emitting elements having luminous efficiency greater than that of at least one of the three light emitting elements specifying the first color gamut.

2. The color OLED device claimed in claim 1 wherein the additional color is within the first color gamut.

3. The color OLED device claimed in claim 1 wherein the additional color is outside the first color gamut, and in combination with the light emitted by the three light-emitting elements specifying the first color gamut specifies a second expanded color gamut.

4. The color OLED device claimed in claim 1 wherein the three colors of light specifying the first color gamut include red, green, and blue.

5. The color OLED device claimed in claim 1 wherein additional light-emitting element emits yellow light.

6. The color OLED device claimed in claim 1 wherein additional light-emitting element emits cyan light.

7. The color OLED device claimed in claim 1 wherein each pixel emits red, green, blue, and yellow.

8. The color OLED device claimed in claim 1 wherein each pixel emits red, green, blue, and cyan.

9. The color OLED device claimed in claim 1 wherein each pixel emits red, green, blue, yellow, and cyan.

10. The color OLED device claimed in claim 1, further comprising a controller for controlling the color OLED device.

11. The color OLED device claimed in claim 10, wherein the controller converts a three-color signal to a converted four-or-more color signal driving the color OLED display device.

12. The color OLED device claimed in claim 10, wherein the converted signal reduces the power usage or increases the lifetime of the color OLED device.

13. The color OLED device claimed in claim 1, wherein the light-emitting elements are of different sizes.

14. The color OLED device claimed in claim 1, wherein the frequency range of the light emitted by the additional light-emitting element overlaps at least some of the frequency range of the light emitted by one or more of the other light-emitting elements.

15. The color OLED device claimed in claim 1 wherein the filters are formed by light-absorbent materials through which the light from the broadband light-emitting electroluminescent organic material passes.

16. The color OLED device claimed in claim 1 wherein the filters are formed by dielectric stacks providing optical interference in light passing through the stacks.

17. The color OLED device claimed in claim 1 wherein the filters are formed by electrodes that are at least partially reflective and that form an optical cavity that filters the broadband light.

18. The color OLED device claimed in claim 1 wherein the filters are formed by secondary light emitters of colored light stimulated by the broadband light.

19. The color OLED device claimed in claim 1 wherein the filters are formed using a plurality of filtering techniques.

20. The OLED device in claim 1, wherein the OLED device is an active-matrix device.

21. The OLED device in claim 1, wherein the OLED device is a passive-matrix device.

22. The OLED device in claim 1, further comprising pixels without the additional light-emitting element.

23. The OLED device in claim 1, comprising pixels having a different number of light-emitting elements of different colors.

24. The OLED device in claim 1, wherein the frequency range of the filter of the additional light emitting element is matched to correspond to a local maximum of the broadband light emission spectrum.

25. The OLED device in claim 1, wherein each light-emitting element comprises only two light-emitting layers of electroluminescent organic material that in combination produce the broadband light having a variable frequency-dependent luminous efficacy emission spectrum.

26. The OLED device in claim 25, wherein the frequency range of the filter of the additional light emitting element is matched to correspond to a local maximum of the broadband light emission spectrum corresponding to the light emitted from one of the light-emitting layers of electroluminescent organic material.