Light guide for coupling differently shaped light source and receiver
View Patent ↗A light guide for interfacing between a light source having a light emitting surface with a first shape and a light receiver with a light receiving surface of a second shape. The light guide has a light emitting end having a first shape of substantially the same size as the first shape of the light emitting surface. A light receiving end has a second shape of substantially the same size as the second shape of the light receiving surface. A free form body between the light emitting end and the light receiving end causes a transition between the first and second shape.
1. A light guide for interfacing a light source having a light emitting surface having a first shape and a light receiver having a light receiving surface of a second shape, the light guide comprising:
a light receiving end having a first shape of substantially the same size as the first shape of the light emitting surface;
a light emitting end having a second shape of substantially the same size as the second shape of the light receiving surface; and
a free form body connecting the light emitting end and the light receiving end having a shape transitioning between the first shape of the light receiving end and the second shape of the light emitting end,
wherein the first shape of the light receiving end is a different shape than the second shape of the light emitting end, and
wherein the free form body is configured so that when light enters the light receiving end from the light source, the light bounces between surfaces of the free form body due to total internal reflection and exits the light emitting end.
2. The light guide of claim 1 , wherein the first shape of the light receiving end is a rectangle and the second shape of the light emitting end is a circle.
3. The light guide of claim 1 , wherein the first shape of the light receiving end is a square.
4. The light guide of claim 1 , wherein the second shape of the light emitting end is a polygon.
5. The light guide of claim 1 , wherein the light source is an LED package.
6. The light guide of claim 1 , wherein the light guide is fabricated from one of glass, quartz, polymeric material or fused fiber.
7. The light guide of claim 1 , wherein at least one of the light receiving end or the light emitting end is coated with anti-reflection film or a wavelength filter.
8. The light guide of claim 1 , wherein the light source has multiple colors.
9. The light guide of claim 1 , wherein the light guide is doped with color to achieve spectral characteristics.
10. A method of producing a light guide to interface a light source having a light emitting surface having a first shape with a light receiver having a light receiving surface of a second shape, comprising:
forming a light receiving end of the light guide having a first shape of substantially the same size as the first shape of the light emitting surface;
forming a light emitting end of the light guide having a second shape of substantially the same size as the second shape of the light receiving surface; and
forming a free form body connecting the light emitting end and the light receiving end having a shape transitioning between the first shape of the light receiving end and the second shape of the lighting emitting end,
wherein the first shape of the light receiving end is a different shape than the second shape of the light emitting end, and
wherein the free form body is configured so that when light enters the light receiving end from the light source, the light bounces between surfaces of the free form body due to total internal reflection and exits the light emitting end.
11. The method of claim 10 , wherein the first shape of the light receiving end is a rectangle and the second shape of the light emitting end is a circle.
12. The method of claim 10 , wherein the first shape of the light receiving end is a square.
13. The method of claim 10 , wherein the second shape of the light emitting end is a polygon.
14. The method of claim 10 , wherein the light source is an LED package.
15. The method of claim 10 , wherein the light guide is fabricated from one of glass, quartz, polymeric material or fused fiber.
16. The method of claim 10 , further comprising:
coating at least one of the light receiving end or the light emitting end with anti-reflection film or a wavelength filter.
17. The method of claim 10 , wherein the light source has multiple colors.
18. The method of claim 10 , wherein the light guide is doped with color to achieve spectral characteristics.
19. The light guide of claim 1 , wherein the free form body has a thickness that changes at a substantially constant rate from the light receiving end to the light emitting end.
20. The light guide of claim 1 , wherein points on the free form body can be expressed in cylindrical coordinates (φ, r, z) as:
{
φ
=
(
-
arctan
(
b
/
a
)
,
arctan
(
b
/
a
)
)
⋁
(
π
-
arctan
(
b
/
a
)
,
π
+
arctan
(
b
/
a
)
)
r
=
a
(
L
-
z
)
+
2
cos
φ
(
R
-
z
)
2
cos
φ
L
z
=
(
0
,
L
)
or
{
φ
=
(
arctan
(
b
/
a
)
,
π
-
arctan
(
b
/
a
)
)
⋁
(
π
+
arctan
(
b
/
a
)
,
-
arctan
(
b
/
a
)
)
r
=
a
(
L
-
z
)
+
2
sin
φ
(
R
-
z
)
2
sin
φ
L
z
=
(
0
,
L
)
wherein, for each point along the free form body, “φ” represents an angle for that point from a fixed plane, “r” represents a distance of that point from a central axis of the light guide, and “z” represents a position along a length L of the light guide, and
wherein “a” is a length of the second surface, “b” is a width of the second surface, “R” is a radius associated with the first surface, and “L” is the length of the light guide.
21. The method of claim 10 , wherein the free form body has a thickness that changes at a substantially constant rate from the light receiving end to the light emitting end.
22. The method of claim 10 , wherein points on the free form body can be expressed in cylindrical coordinates (φ, r, z) as:
{
φ
=
(
-
arctan
(
b
/
a
)
,
arctan
(
b
/
a
)
)
⋁
(
π
-
arctan
(
b
/
a
)
,
π
+
arctan
(
b
/
a
)
)
r
=
a
(
L
-
z
)
+
2
cos
φ
(
R
-
z
)
2
cos
φ
L
z
=
(
0
,
L
)
or
{
φ
=
(
arctan
(
b
/
a
)
,
π
-
arctan
(
b
/
a
)
)
⋁
(
π
+
arctan
(
b
/
a
)
,
-
arctan
(
b
/
a
)
)
r
=
a
(
L
-
z
)
+
2
sin
φ
(
R
-
z
)
2
sin
φ
L
z
=
(
0
,
L
)
wherein, for each point along the free form body, “φ” represents an angle for that point from a fixed plane, “r” represents a distance of that point from a central axis of the light guide, and “z” represents a position along a length L of the light guide, and
wherein “a” is a length of the second surface, “b” is a width of the second surface, “R” is a radius associated with the first surface, and “L” is the length of the light guide.