Inorganic-based color conversion matrix element for organic color display devices and method of fabrication

• US 6,608,439 B1
• Filed: 05/03/2000
• Issued: 08/19/2003
• Est. Priority Date: 09/22/1998
• Status: Expired due to Term

• Current Assignee: eMagin Corporation (Samsung Electronics Co. Ltd.)
• Original Assignee: eMagin Corporation (Samsung Electronics Co. Ltd.)
• Inventors: Sokolik, Igor, Campos, Richard A.
• Primary Examiner(s): Patel, Nimeshkumar D.
• Assistant Examiner(s): Santiago, Mariceli
• Application Number:
  US09/530,604
• Time in Patent Office: 1,203 Days
• Field of Search: 313/501, 313/504, 313/506, 313/512
• US Class Current: 313/512
• CPC Class Codes: B82Y 20/00 Nanooptics, e.g. quantum optics or photonic crystals
• CPC Class Codes: B82Y 30/00 Nanotechnology for materials or surface science, e.g. nanocomposites
• CPC Class Codes: H10K 2102/3026 Top emission
• CPC Class Codes: H10K 2102/331 Nanoparticles used in non-emissive layers, e.g. in packaging layer
• CPC Class Codes: H10K 50/841 Self-supporting sealing arrangements
• CPC Class Codes: H10K 59/38 comprising colour filters or colour changing media [CCM]
• CPC Class Codes: H10K 59/871 Self-supporting sealing arrangements

Abstract

An integrated organic light emitting diode (OLED) color display device is disclosed. The OLED display device comprises at least one pixel element (10) capable of emitting visible light of varying wavelengths. Pixel element (10) may comprise: a substrate (100), an addressable two-dimensional matrix of organic light emitting diodes (120) that emits monochrome light, a color conversion matrix element (110) capable of absorbing the monochrome light and re-emitting that light at different wavelengths, and cover element (130). Color conversion matrix element (110) may further comprise at least one red color converting subelement (111), at least one green color converting subelement (112), and at least one blue color converting subelement (113). The color converting subelements (111, 112, and 113) may further comprise semiconductor nanocrystals (140) uniformly dispersed in a transparent organic binding material (150). The size distribution of the semiconductor nanocrystals (140) may be precisely controlled to define the capability for color conversion to a particular wavelength of re-emitted light. The color conversion matrix element (110) is fabricated separately from the organic light emitting diode matrix. A method for making an integrated organic light emitting diode display device comprising at least one pixel element (10) capable of emitting visible light of varying wavelengths is also disclosed.

Claims

1. A pixel clement for an organic light emitting diode display device;

said pixel element capable of emitting visible light of varying wavelengths comprising;

a substrate;

a transparent element through which said visible light is emitted;

an addressable two-dimensional organic light emitting diode matrix that emits monochrome light, in contact with at least one of said substrate and said transparent element;

a color conversion matrix element for conversion of the wavelength of said monochrome light, in contact with said organic light emitting diode matrix and at least one of said substrate and said transparent element;

a cover element for protecting said color conversion matrix element and said organic light emitting diode matrix against physical, chemical or thermal damage, in contact with at least one of said color conversion matrix element and said organic light emitting diode matrix; and

wherein said color conversion matrix element absorbs said monochrome light emitted from said organic light emitting diode matrix and re-emits said visible light at different wavelengths;

wherein said color conversion matrix element further comprises a two-dimensional array of color conversion elements;

wherein said color conversion matrix element further comprises at least one red, at least one green and at least one blue converting subelement;

wherein said color conversion matrix element further comprises a plurality of semiconductor nanocrystals uniformly dispersed in a transparent organic binding material.

2. The pixel element of claim 1, wherein said color conversion matrix element is fabricated independently from said organic light emitting diode matrix.

3. The pixel element of claim 2, wherein said semiconductor nanocrystals are selected from the group of the semiconductor compounds CdS, CdSe and CdTe and mixtures of two or more of said semiconductor compounds.

4. The pixel element of claim 3, wherein the color of said visible light re-emitted by said color conversion matrix element is tunable by altering the size of said semiconductor nanocrystals.

5. The pixel element of claim 4, wherein the size distribution of said semiconductor nanocrystals is precisely controlled to define the capability for color conversion to a particular wavelength of re-emitted light.

6. The pixel element of claim 5, wherein said red color converting subelement further comprises semiconductor nanocrystals that absorb said monochrome light emitted from said organic light emitting diode matrix and re-emit said monochrome light as red light.

7. The pixel element of claim 5, wherein said green color converting subelement further comprises semiconductor nanocrystals that absorb said monochrome light emitted from said organic light emitting diode matrix and re-emit said monochrome light as green light.

8. The pixel element of claim 5, wherein said blue color converting subelement further comprises at least one of

(a) said transparent organic binding material without semiconductor nanocrystals such that said blue color converting subelements transparent to said monochrome light; and

(b) an optical filter without semiconductor nanocrystals, capable of spectrum correction and transparent to said monochrome light.

9. The pixel element of claim 4, wherein said substrate is said transparent element.

10. The pixel element of claim 9, wherein said cover is formed in contact with said organic light emitting diode matrix.

11. The pixel element of claim 10, wherein said pixel element is a component of a “

down-emitting”

OLED display device.

12. The pixel element of claim 1, wherein said color conversion matrix element comprises at least one layer.

13. The pixel element of claim 1, wherein said organic light emitting diode matrix is formed in contact with said substrate.

14. The pixel element of claim 13, wherein said substrate is opaque.

15. The pixel element of claim 14, wherein said cover is formed in contact with said color conversion matrix element.

16. The pixel element of claim 15, wherein said cover is said transparent element.

17. The pixel element of claim 16, wherein said pixel element is a component of an “

up-emitting”

OLED display device.

18. A color display device for providing an image utilizing light emitted from at least one pixel element capable of emitting visible light of varying wavelengths, said display device comprising:

a substrate;

a transparent element through which said visible light is emitted;

an addressable two-dimensional organic light emitting diode matrix that emits monochrome light, in contact with at least one of said substrate and said transparent element;

a color conversion matrix element for conversion of the wavelength of said monochrome light, in contact with said organic light emitting diode matrix and at least one of said substrate and said transparent element; and

wherein said color conversion matrix element;

(a) absorbs said monochrome light emitted from said organic light emitting diode matrix and re-emits said visible light at different wavelengths;

(b) further comprises a two-dimensional array of color conversion elements;

(c) further comprises at least one red, at least one green, and at least one blue color converting subelement;

(d) further comprises a plurality of semiconductor nanocrystals uniformly dispersed in a transparent organic binding material;

(e) further comprises at least one layer; and

(f) is fabricated independently from said organic light emitting diode matrix; and

a cover element for protecting said color conversion matrix element and said organic light emitting diode matrix against physical, chemical or thermal damage, in contact with at least one of said color conversion matrix element and said organic light emitting diode matrix.

19. The display device of claim 18, wherein said semiconductor nanocrystals are selected from the group of the semiconductor compounds CdS, CdSe and CdTe and mixtures of two or more of said semiconductor compounds.

20. The display device of claim 19, wherein the color of said visible light re-emitted by said color conversion matrix element is tunable by altering the size of said semiconductor nanocrystals.

21. The display device of claim 20, wherein the size distribution of said semiconductor nanocrystals is precisely controlled to define the capability for color conversion to a particular wavelength of re-emitted light.

22. The display device of claim 21, wherein said red color converting subelement further comprises semiconductor nanocrystals that absorb said monochrome light emitted from said organic light emitting diode matrix and re-emit said monochrome light as red light;

said green color converting subelement further comprises semiconductor nanocrystals that absorb said monochrome light emitted from said organic light emitting diode matrix and re-emit said monochrome light as green light; and

said blue color converting subelement further comprises at least one of

(a) said transparent organic binding material without semiconductor nanocrystals such that said blue color converting subelement is transparent to said monochrome light; and

(b) an optical filter without semiconductor nanocrystals, capable of spectrum correction and transparent to said monochrome light.

23. The display device of claim 21, wherein said blue color converting subelement further comprises semiconductor nanocrystals that absorb said monochrome light emitted from said organic light emitting diode matrix and re-emit said monochrome light as a different wavelength of blue light.

24. The display device of claim 21, wherein said color conversion matrix element is formed in contact with said substrate.

25. The display device of claim 24, wherein said substrate is said transparent element.

26. The display device of claim 25, wherein said cover is formed in contact with said organic light emitting diode matrix.

27. The display device of claim 26, wherein said display device is a “

down-emitting”

OLED display device.

28. The displace device of claim 21, wherein said organic light emitting diode matrix is formed in contact with said substrate.

29. The display device of claim 28, wherein said substrate is opaque.

30. The display device of claim 29, wherein said cover is formed in contact with said color conversion matrix element.

31. The display device of claim 30, wherein said cover is said transparent element.

32. The display device of claim 31, wherein said display device is an “

up-emitting”

OLED display device.

33. A method of fabricating an integrated organic light emitting diode color display device comprising at least one pixel element capable of emitting visible light of varying wavelengths, comprising the steps of:

forming a substrate;

forming a transparent element through which said visible light is emitted;

forming an addressable two-dimensional organic light emitting diode matrix that emits monochrome light, in contact with at least one of said substrate and said transparent element;

forming a color conversion matrix element for conversion of the wavelength of said monochrome light, in contact with said organic light emitting diode matrix and at least one of said substrate and said transparent element;

wherein said color conversion matrix element absorbs said monochrome light emitted from said organic light emitting diode matrix and re-emits said visible light at different wavelengths;

forming a cover element for protecting said color conversion matrix element and said organic light emitting diode matrix against physical, chemical or thermal damage, in contact with at least one of said color conversion matrix element and said organic light emitting diode matrix; and

wherein said step of forming said color conversion matrix element is independent from said step of forming said organic light emitting diode matrix;

wherein said color conversion matrix element further comprises a plurality of semiconductors nanocrystals uniformly dispersed in a transparent organic binding material.

34. The method of claim 33, further comprising the step of altering the size of said semiconductor nanocrystals in order to tune the color of said visible light re-emitted by said color conversion matrix element.

35. The method of claim 34, further comprising the step of precisely controlling the size distribution of said semiconductor nanocrystals in order to define the capability for color conversion to a particular wavelength of re-emitted light.