Waveguide having unidrectional illuminance
A luminaire includes an optical waveguide having a first surface and a second surface opposite the first surface, and a light source associated with the optical waveguide. At least about 80% of light produced by the light source is directed by the waveguide into an illumination distribution emitted from the first surface of the optical waveguide.
1. A display lighting element for viewing of an object disposed therein, comprising:
a luminaire comprising:
a transparent optical waveguide comprising a primary light-emitting surface and a secondary surface opposite the primary light-emitting surface;
a light source coupled to the transparent optical waveguide; and
a plurality of light extraction features disposed on the primary light-emitting surface; and
wherein the plurality of light extraction features comprises a first portion adjacent to the primary light-emitting surface and a second portion distal from the primary light-emitting surface, wherein the first portion comprises a truncated hemispherical shape in cross section and the second portion comprises one of a truncated conical shape and a cylindrical shape in cross section such that the plurality of light extraction features develop a directional illumination distribution through the primary light-emitting surface in a direction away from the secondary surface onto the object displayed,
a display case comprising a housing wherefrom the display lighting element is suspended;
wherein the object is viewable through the secondary surface and the primary light-emitting surface by a direct line-of-sight.
2. The display lighting element of claim 1 , wherein the first portion is undercut relative to the primary light-emitting surface between an aperture adjacent the primary light-emitting surface and the second portion.
3. The display lighting element of claim 2 , wherein the second portion is disposed between the first portion and a base opposite the aperture.
4. The display lighting element of claim 3 , wherein the plurality of light extraction features comprises a first extraction feature comprising a first height and a second extraction feature comprising a second height different from the first height.
5. The display lighting element of claim 3 , wherein the plurality of light extraction features comprises a first extraction feature comprising a first aperture diameter and a second extraction feature comprising a second aperture diameter different from the first aperture diameter.
6. The display lighting element of claim 3 , wherein the plurality of light extraction features comprises a first extraction feature comprising a first base diameter and a second extraction feature comprising a second base diameter different from the first base diameter.
7. The display lighting element of claim 1 , wherein at least about 90% of light is emitted from the primary light-emitting surface of the optical waveguide.
8. The display lighting element of claim 1 , wherein at least about 95% of light is emitted from the primary light-emitting surface of the optical waveguide.
9. A luminaire, comprising:
a transparent optical waveguide comprising a primary light-emitting surface and a secondary surface opposite the primary light-emitting surface;
a light source coupled to the transparent optical waveguide;
a plurality of light extraction features disposed on the primary light-emitting surface; and
wherein the plurality of light extraction features comprises a first portion adjacent to the primary light-emitting surface and a second portion distal from the primary light-emitting surface, and wherein the first portion comprises a truncated hemispherical shape in cross section and the second portion comprises one of a truncated conical shape and a cylindrical shape in cross section such that light is directionally extracted from the primary light-emitting surface in a direction away from the secondary surface to illuminate a surrounding that is viewable through the transparent optical waveguide;
a housing wherefrom the luminaire is vertically suspended for providing general illumination lighting in a direction away from a viewer.
10. The luminaire of claim 9 , wherein the light source is disposed within the housing, and wherein a coupling end of the transparent optical waveguide is disposed in the housing adjacent to the light source.
11. The luminaire of claim 10 , wherein the first portion is undercut relative to the primary light-emitting surface between an aperture adjacent the primary light-emitting surface and the second portion.
12. The luminaire of claim 11 , wherein the second portion is disposed between the first portion and a base opposite the aperture.
13. The luminaire of claim 12 , wherein the plurality of light extraction features comprises a first extraction feature comprising a first height and a second extraction feature comprising a second height different from the first height.
14. The luminaire of claim 12 , wherein the plurality of light extraction features comprises a height of between about 10 μm and about 500 μm.
15. The luminaire of claim 12 , wherein the second portion comprises a height of between about 10 μm and about 100 μm.
16. The luminaire of claim 12 , wherein the plurality of light extraction features is disposed in a hexagonal array.
17. A method of illumination using an optical waveguide comprising a primary light-emitting surface and a secondary surface opposite the primary light-emitting surface, the method comprising:
providing the optical waveguide;
injecting light into the optical waveguide; and
wherein the waveguide comprises a plurality of light extraction features that produce an illumination characteristic resulting from the plurality of extraction features directing light out of the optical waveguide away from the primary light-emitting surface;
wherein the plurality of light extraction features comprises a first portion adjacent to the primary light-emitting surface and a second portion distal from the primary light-emitting surface; and
wherein the first portion comprises a truncated hemispherical shape in cross section and the second portion comprises one of a truncated conical shape and a cylindrical shape in cross section;
directionally extracting light from the primary light-emitting surface through the plurality of light extraction features in a direction away from the secondary surface to direct light onto an object that is viewable through the secondary surface and the primary light-emitting surface.
18. A method of illumination using an optical waveguide comprising a primary light-emitting surface and a secondary surface opposite the primary light-emitting surface, the method comprising:
providing the optical waveguide;
disposing a plurality of light extraction features onto the primary light-emitting surface, the plurality of light extraction features comprising a first portion adjacent to the primary light-emitting surface and a second portion distal from the primary light-emitting surface, wherein the first portion comprises a truncated hemispherical shape in cross section and the second portion comprises one of a truncated conical shape and a cylindrical shape in cross section;
injecting light into the optical waveguide;
arranging a light source within a housing;
mounting the optical waveguide on the housing wherein a coupling end of the optical waveguide is disposed in the housing adjacent to the light source; and
directionally extracting light from the primary light-emitting surface through the plurality of light extraction features in a direction away from the secondary surface to direct at least 95% of the injected light out of the optical waveguide and onto an object that is viewable through the secondary surface and the primary light-emitting surface.
19. The method of claim 18 , wherein the disposing comprises disposing the plurality of light extraction features in a hexagonal array.