Resonant microcavity display

• US 5,469,018 A
• Filed: 07/20/1993
• Issued: 11/21/1995
• Est. Priority Date: 07/20/1993
• Status: Expired due to Fees

• Current Assignee: Quantum Vision
• Original Assignee: The University of Georgia Research Foundation, Inc.
• Inventors: Jacobsen, Stuart M., Jones, Michieal L., Jaffe, Steven M., Eilers, Hergen
• Primary Examiner(s): O'Shea, Sandra L.
• Assistant Examiner(s): Patel, Vip
• Application Number:
  US08/094,767
• Time in Patent Office: 854 Days
• Field of Search: 313/461, 313/466, 313/474, 313/506, 313/509
• US Class Current: 313/461
• CPC Class Codes: H01J 29/28 with protective, conductive or reflective layers
• CPC Class Codes: H01J 61/42 by transforming the wavelength of the light by luminescence
• CPC Class Codes: H01J 63/06 Lamps with luminescent screen excited by the ray or stream
• CPC Class Codes: H05B 33/12 Light sources with substantially two-dimensional radiating surfaces
• CPC Class Codes: H05B 33/22 characterised by the chemical or physical composition or the arrangement of auxiliary dielectric or reflective layers

Abstract

A resonant microcavity display, comprising a thin-film resonant microcavity with a phosphor active region is disclosed. The microcavity comprises: a rigid substrate; a front reflector disposed upon the rigid substrate; a phosphor active region disposed upon the front reflector; and a back reflector disposed upon the active region. The display preferentially emits light that propagates along the axis perpendicular to plane of the display, due to its quantum mechanical properties. It exhibits high external efficiency, highly controllable chromaticity, high resolution, highly directional output and highly efficient heat transfer characteristics. For these reasons it provides a suitable display element for projection screen television, high definition television, direct view television, flat panel displays, optical coupling, and other applications.

Claims

1. A luminescent display, comprising a thin-film resonant microcavity with an active region, said active region having a phosphor disposed therein for emitting light.

2. The luminescent display of claim 1 wherein said microcavity comprises:

a. a rigid substrate;

b. a front reflective region disposed upon said substrate;

c. said active region disposed upon said front reflective region; and

d. a back reflective region disposed upon said active region; and

at least one of said front and said back reflective regions is partially reflective, so that light produced by excitation of said active region forms a standing wave between said front reflective region and said back reflective region and is emitted through said at least one partially reflective region.

3. The luminescent display of claim 2 wherein said rigid substrate comprises a material that is transparent.

4. The luminescent display of claim 2 wherein said rigid substrate is crystalline.

5. The luminescent display of claim 2 wherein said rigid substrate is amorphous.

6. The luminescent display of claim 2 wherein said front reflective region and back reflective region are dielectric reflectors.

7. The luminescent display of claim 6 wherein said dielectric reflectors further comprise a plurality of alternating parallel layers wherein layers comprising a material with a relatively low index of refraction alternate with layers comprising a material with a relatively high index of refraction.

8. The luminescent display of claim 7 wherein said material with a relatively low index of refraction is selected from fluorides and oxides.

9. The luminescent display of claim 7 wherein said material with a relatively high index of refraction is selected from sulfides, selenides, nitrides, and oxides.

10. The luminescent display of claim 2 wherein said front reflective region is a metallic reflector.

11. The luminescent display of claim 2 wherein said back reflective region is a metallic reflector.

12. The luminescent display of claim 2 wherein said active region comprises a phosphor selected from sulfides, oxides, silicates, oxysulfides, and aluminates.

13. The luminescent display of claim 2 wherein said active region comprises an activator selected from transition metals, rare earths and color centers.

14. The luminescent display of claim 2 wherein the distance between said front reflective region and said back reflective region is equal to the desired wavelength of light to be emitted by the display multiplied by an integer and divided by the quantity 4 times the index of refraction for light of the desired wavelength of the material used in the active region.

15. The luminescent display of claim 2 wherein the distance between said front reflective region and said back reflective region is equal to the desired wavelength of light to be emitted by the display multiplied by an integer and divided by the quantity 2 times the index of refraction for light of the desired wavelength of the material used in the active region.

16. The luminescent display of claim 2 disposed upon the viewing screen of a cathode ray tube.

17. The luminescent display of claim 2 further comprising a conductive layer disposed upon said back reflective region to channel off electrons.

18. The luminescent display of claim 1 wherein said phosphor is excited by electrons.

19. The luminescent display of claim 17 further comprising a cathode ray tube to generate said exciting electrons.

20. The luminescent display of claim 1 wherein said phosphor is excited by an electric field.

21. The luminescent display of claim 1 wherein said phosphor is excited by light.

22. The luminescent display of claim 21 wherein said conductive layer is made of aluminum.

23. The luminescent display of claim 1 wherein said phosphor is selected to have a controlled excited-state decay time.

24. A method of producing a luminescent display, which comprises growing a resonant microcavity, including a phosphor active region inside said microcavity, on a rigid substrate.

25. The method of claim 24 wherein said phosphor is selected to control the phosphor decay time.

26. The method of claim 24 wherein said active region has a width selected to control the chromaticity of the light emitted from the display.

27. The method of claim 26 wherein the width of said active region is selected so that it is equal to an integer number of quarter wavelengths of light corresponding to a selected chromaticity.

28. The method of claim 26 wherein the width of said active region is selected so that it is equal to an integer number of half wavelengths of light corresponding to a selected chromaticity.

29. The method of claim 24 wherein said microcavity has a width selected such that the microcavity has a resonance frequency that lies within the phosphor'"'"'s natural luminescence resonance.

30. The method of claim 24 wherein said rigid substrate is selected to maximize the heat transfer efficiency of the display.

31. The method of claim 24 wherein said microcavity is designed to control the directionality of the light emitted from the display.