Color-tunable light emitter
View Patent ↗The color-tunable light emitter has a first electrode and a light-generating layer adjacent the first electrode. The light-generating layer is operable to generate light in a band of wavelengths. The color-tunable light emitter also includes an electro-optical layer, a second electrode adjacent the electro-optical layer and a corrugated metal layer between the light-generating layer and the electro-optical layer. The corrugated metal layer couples a sub-band of the light from the light-generating layer to the electro-optical layer. The sub-band has a center wavelength dependent on a voltage applied to at least one of the electrodes.
1. A color-tunable light emitter, comprising:
a first electrode;
a light-generating layer adjacent the first electrode, the light-generating layer operable to generate light in a band of wavelengths;
an electro-optical layer;
a second electrode adjacent the electro-optical layer, and
a corrugated metal layer between the light-generating layer and the electro-optical layer, the corrugated metal layer coupling a sub-band of the light from the light-generating layer to the electro-optical layer, the sub-band having a center wavelength dependent on a voltage applied to at least one of the electrodes.
2. The light emitter of claim 1 , additionally comprising a diffuser layer adjacent the second electrode.
3. The light emitter of claim 1 , additionally comprising an optical waveguide between the light-generating layer and the corrugated metal layer.
4. The light emitter of claim 3 , in which the optical waveguide comprises a layer having a thickness in the range from about 500 nm to about 1,000 nm.
5. The light emitter of claim 4 , in which the layer comprises a material selected from nitrides and fused silica.
6. The light emitter of claim 1 , in which the light-generating layer comprises a material selected from an electro-luminescent material, a photo-luminescent material, and a cathode-luminescent material.
7. The light emitter of claim 1 , in which the electro-optical layer comprises liquid crystal material.
8. The light emitter of claim 7 , in which the liquid crystal material is a nematic liquid crystal material and is encapsulated in a porous silicon matrix.
9. The light emitter of claim 1 , in which the second electrode is transparent in the band of wavelengths.
10. The light emitter of claim 1 , in which:
the light generated by the light-generating layer has a brightness dependent on a first voltage applied between the first electrode and the corrugated metal layer; and
the center wavelength of the sub-band is dependent on a second voltage applied between the second electrode and the corrugated metal layer.
11. A method for generating color-tunable light, the method comprising:
providing an electro-optical layer and a corrugated metal layer;
juxtaposing the corrugated metal layer and the electro-optical layer;
illuminating the corrugated metal layer with light in a band of wavelengths;
coupling a sub-band of the light through the corrugated metal layer to the electro-optical layer, the sub-band having a center wavelength; and
adjusting the refractive index of the electro-optical layer to tune the center wavelength by changing a voltage across the electro-optical layer.
12. The method of claim 11 , in which the illuminating comprises:
providing a light-generating layer; and
juxtaposing the light-generating layer and the corrugated metal layer.
13. The method of claim 12 , in which:
the light-generating layer comprises photo-luminescent material; and
the illuminating additionally comprises optically pumping the photo-luminescent material.
14. The method of claim 12 , in which:
the light-generating layer comprises electro-luminescent material; and
the illuminating additionally comprises applying voltage across the electro-luminescent material.
15. The method of claim 11 , in which the illuminating comprises generating the light by one of electro-luminescence, photo-luminescence, and cathode-luminescence.
16. The method of claim 11 , in which the illuminating comprises:
providing an optical waveguide layer;
juxtaposing the optical waveguide layer and the corrugated metal layer; and
illuminating the optical waveguide layer.
17. A color display, comprising:
opposed electrodes, at least one of the electrodes comprising electrode segments defining respective color-tunable light emitters; and
between the electrodes, a layer structure comprising:
a light-generating layer operable to generate light in a band of wavelengths,
an electro-optical layer, and
a corrugated metal layer between the light-generating layer and the electro-optical layer, the corrugated metal layer coupling a sub-band of the light generated by the light-generating layer to the electro-optical layer, the sub-band having a center wavelength, the center wavelength of each of the color-tunable light emitters dependent on a voltage applied to the respective one of the electrode segments.
18. The display of claim 17 , additionally comprising dielectric spacers between the electrode segments.
19. The display of claim 18 , in which the dielectric spacers extend through the layer structure.
20. The display of claim 17 , in which the electro-optical layer comprises liquid crystal material.
21. The display of claim 20 , in which the liquid crystal material is a nematic liquid crystal material and is encapsulated in a porous silicon matrix.
22. The display of claim 17 , in which the second electrode is transparent in the band of wavelengths.
23. The display of claim 17 , in which both electrodes comprise electrode segments.
24. The display of claim 23 , in which, in each of the color-tunable light emitters:
the light generated by the light-generating layer has a brightness dependent on a first voltage applied between the corrugated metal layer and the respective one of the electrode segments the one of the electrodes adjacent the light-generating layer; and
the center wavelength of the sub-band is dependent on a second voltage applied between the corrugated metal layer and the respective one of the electrode segments of the electrode adjacent the electro-optical layer.
25. A method for generating color-tunable light, the method comprising:
providing an electro-optical layer and a corrugated metal layer;
juxtaposing the corrugated metal layer and the electro-optical layer;
illuminating the corrugated metal layer with light in a band of wavelengths;
coupling a sub-band of the light through the corrugated metal layer to the electro-optical layer, the sub-band having a center wavelength; and
adjusting the refractive index of the electro-optical layer to tune the center wavelength;
wherein the illuminating comprises providing a light-generating layer comprising electro-luminescent material, and juxtaposing the light-generating layer and the corrugated metal layer; and
the illuminating additionally comprises applying voltage across the electro-luminescent material.