Waveguide Having Unidirectional 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 luminaire, comprising:
an optical waveguide having a first surface and a second surface opposite the first surface;
a light source associated with the optical waveguide;
wherein 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.
2 . The luminaire of claim 1 , wherein at least about 90% of light is emitted from the first surface of the optical waveguide.
3 . The luminaire of claim 1 , wherein at least about 95% of light is emitted from the first surface of the optical waveguide
4 . The luminaire of claim 3 , wherein the optical waveguide has an optical efficiency of at least 90%.
5 . The luminaire of claim 3 , wherein the optical waveguide has an optical efficiency of at least 95%.
6 . The luminaire of claim 1 , wherein the waveguide includes a plurality of extraction features disposed on the first surface.
7 . The luminaire of claim 6 , wherein each extraction feature comprises an outer surface extending between an aperture adjacent the first surface of the waveguide and a base opposite the aperture, and wherein the outer surface is undercut adjacent the first surface of the waveguide.
8 . The luminaire of claim 7 , wherein the plurality of extraction features includes a first extraction feature having a first height and a second extraction feature having a second height different from the first height.
9 . The luminaire of claim 7 , wherein the plurality of extraction features includes a first extraction feature having a first aperture diameter and a second extraction feature having a second aperture diameter different from the first aperture diameter.
10 . The luminaire of claim 7 , wherein the plurality of extraction features includes a first extraction feature having a first base diameter and a second extraction feature having a second base diameter different from the first base diameter.
11 . The luminaire of claim 6 , wherein the plurality of extraction features is disposed in a hexagonal array.
12 . A luminaire, comprising:
a waveguide having a first surface and a second surface opposite the first surface, wherein the waveguide includes an extraction feature disposed on the first surface; and
a light source associated with the waveguide;
wherein light emitted from the light source is directed by the waveguide into an illumination distribution emitted from the first surface of the waveguide; and
wherein the waveguide is optically transparent such that the illumination distribution is visible along a line of sight through the waveguide extending from the second surface to the first surface.
13 . The luminaire of claim 12 , wherein at least about 90% of light produced by the light source is emitted from the first surface of the waveguide, and wherein the waveguide has an optical efficiency of at least 90%.
14 . The luminaire of claim 12 , wherein the waveguide exhibits a luminance of less than about 5% of light produced by the light source that is visible along the line of sight.
15 . The luminaire of claim 12 , wherein the extraction feature has a curved shape extending between an aperture adjacent the first surface and a base opposite the aperture.
16 . The luminaire of claim 15 , wherein the curved shape has an outer surface that is determined by iteratively plotting points using a differential equation.
17 . The luminaire of claim 16 , wherein the differential equation calculates the curvature of the outer surface that achieves total internal reflection of light at the outer surface of the extraction feature.
18 . The luminaire of claim 17 , wherein the differential equation calculates a slope a point along the outer surface and comprises:
Slope
=
-
h
R
=
tan
(
+
α
)
wherein α represents a complementary angle of a maximum angle of incidence enabling total internal reflection;
wherein φ is the defined by a light ray incident on the point having coordinates (h, R+R o ) relative to an edge of the aperture opposite the point, and wherein φ is calculated in accordance with:
ϕ
=
ArcTan
(
n
R
+
Ro
)
wherein h is a distance from the first surface of the waveguide, R O is a radius of the aperture, and R is a distance from a centerline of the extraction feature to the point.
19 . The luminaire of claim 15 , wherein the curved shape has a height of between about 10 μm and about 500 μm.
20 . The luminaire of claim 15 , wherein the curved shape includes a first portion adjacent the aperture and a second portion adjacent the base.
21 . The luminaire of claim 20 , wherein the first portion has an outer surface that is undercut relative to the first surface of the waveguide.
22 . The luminaire of claim 20 , wherein the second portion has a cylindrical shape.
23 . The luminaire of claim 20 , wherein the second portion has a height of between about 10 μm and about 100 μm.
24 . The luminaire of claim 12 , wherein the waveguide and the extraction feature comprise the same material.
25 . The luminaire of claim 12 , further comprising a member, wherein the base of the extraction feature is disposed on the member.
26 . The luminaire of claim 25 , wherein the member is comprised of a material selected from the group of a film, a glass, a polyester, and an acrylic.
27 . The luminaire of claim 12 , wherein a bonding feature formed atop the aperture is displaced during joining of the extraction feature to the light emitting surface of the waveguide.
28 . The luminaire of claim 12 , wherein the luminaire produces an asymmetric illumination distribution.
29 . The luminaire of claim 12 , wherein the luminaire has an overall efficiency of at least 90%.
30 . A luminaire, comprising:
a housing;
an LED element disposed within the housing;
a waveguide having a light emitting surface disposed in the housing adjacent the LED element; and
an extraction feature disposed on the light emitting surface of the waveguide;
wherein the extraction feature has a curved shape extending between an aperture adjacent the light emitting surface and a base opposite the aperture.
31 . The luminaire of claim 30 , wherein the LED element is disposed in a first end of the housing, and wherein the waveguide extends out of a second end of the housing opposite the first end.
32 . The luminaire of claim 31 , wherein the LED element is disposed along a coupling surface of the waveguide.