LED illumination device with a highly uniform illumination pattern
An LED (light emitting diode) illumination device that can generate a uniform light output illumination pattern. The illumination source includes first and second reflectors with a conic or conic-like shape. One reflector is mounted in the same plane as the LED and wraps around the front of the LED to redirect the light emitted along a central axis of the LED.
1. An illumination source comprising:
an LED light source with a central axis;
a first reflector having a first reflecting surface with a first conic or conic-like shape, the first reflector passing directly in front of the central axis of the LED light source; and
a second reflector having a second reflecting surface with a second conic or conic-like shape, the second reflector not passing directly in front of the central axis of the LED,
wherein the light reflected off the first reflector is redirected from a positive angle to a dominantly negative angle;
wherein at least a portion of the light reflected off the second reflector is redirected from a negative angle to a positive angle.
2. An illumination source according to claim 1 , wherein at least a portion of the light reflected off the second reflector is redirected from a negative angle to a positive angle.
3. An illumination source according to claim 1 , wherein the conic or conic-like shape of each of the first and second reflectors has a shape selected from the group consisting of: a hyperbola; a parabola; an ellipse; a sphere; or a modified conic.
4. An illumination source according to claim 1 , wherein each of the first and second reflectors is formed of one of: a metal; a metalized surface; or a reflectorized surface.
5. An illumination source according to claim 1 , wherein the first and second reflecting surfaces are revolved in a circle.
6. An illumination source according to claim 1 , wherein the first and second reflecting surfaces are extruded or projected linearly.
7. An illumination source according to claim 5 , wherein the first and second reflecting surfaces are projected along a conic or conic-like curve.
8. An illumination source according to claim 1 , wherein each of said first and second reflecting surfaces satisfies:
z
=
cr
2
1
+
1
-
(
1
+
k
)
c
2
r
2
r
2
=
x
2
+
y
2
,
in which x, y, and z are positions on a 3-axis system, k is conic constant, and c is curvature.
9. An illumination source according to claim 1 , wherein each of said first and second reflecting surfaces satisfies:
z
=
cr
2
1
+
1
-
(
1
+
k
)
c
2
r
2
+
F
r
2
=
x
2
+
y
2
,
in which x, y, and z are positions on a 3-axis system, k is conic constant, c is curvature, and F is an arbitrary function.
10. An illumination source according to claim 6 , wherein each of said first and second reflecting surfaces satisfies:
z
=
cr
2
1
+
1
-
(
1
+
k
)
c
2
r
2
r
2
=
x
2
+
y
2
,
in which x, y, and z are positions on a 3-axis system, k is conic constant, and c is curvature.
11. An illumination source according to claim 7 , wherein each of said first and second reflecting surfaces satisfies:
z
=
cr
2
1
+
1
-
(
1
+
k
)
c
2
r
2
+
F
r
2
=
x
2
+
y
2
,
in which x, y, and z are positions on a 3-axis system, k is conic constant, c is curvature, and F is an arbitrary function.
12. An illumination source according to claim 1 , wherein said first and second conic or conic-like reflecting surfaces are represented by a set of points and a basic curve or a spline fit, resulting in a conic-like shape of said first and second portions of the first reflector.