Light pipe with side-light extraction
View Patent ↗A light pipe with uniform side-light emission has a core comprising a polymer, and a fluoropolymer cladding on the core with a lower refractive index than the core. Light-scattering material is distributed within the core along an active section of light pipe in which side-light emission is desired, with a density gradient chosen to achieve uniform side-light emission. Another light pipe with uniform side-light emission has a core comprising a polymer, and a fluoropolymer cladding on the core with a lower refractive index than the core. Light-scattering material is distributed within at least one of the cladding and the core along an active section of light pipe in which side-light emission is desired, with a density gradient chosen to yield uniform side light emission, and substantially only in a radial swath, along the longitudinal axis of the light pipe, of substantially less than 360 degrees.
1. A light pipe with uniform side-light emission, comprising:
a) a core comprising a polymer and a fluoropolymer cladding on the core; the cladding having a lower refractive index than the core; and
b) light-scattering material distributed within the core along an active section of light pipe in which side-light emission is desired;
c) the light-scattering material being distributed with a non-zero density gradient along a longitudinal axis of the light pipe chosen to achieve uniform side-light emission; and
d) the core lacking any significant variation in refractive index along the longitudinal axis as measured without regard to the presence of the light-scattering material.
2. The light pipe of claim 1 , wherein the light-scattering material comprises titanium dioxide.
3. A light pipe with uniform side-light emission, comprising:
a) a core comprising a polymer and a fluoropolymer cladding on the core; the cladding having a lower refractive index than the core; and
b) light-scattering material distributed within the core along an active section of light pipe in which side-light emission is desired;
c) the light-scattering material being distributed in the core along the active section of the light pipe, substantially only in a radial swath, along the longitudinal axis of the light pipe, of substantially less than 360 degrees, so that light exits the light pipe in a directional manner.
4. The light pipe of claim 3 , wherein the radial swath less than about 180 degrees.
5. The light pipe of claim 4 , wherein the radial swath is more than about 10 degrees.
6. The light pipe of claim 4 , wherein the radial swath is less than about 90 degrees.
7. The light pipe of claim 3 , wherein the lumen output as between inlet and outlet portions of a the active section is within plus or minus 10 percent of the average value of each other.
8. The light pipe of claim 3 , wherein the light-scattering material is uniformly distributed along a longitudinal axis of the active section of the light pipe substantially only in a radial swath, along the longitudinal axis of the light pipe, of substantially less than 360 degrees, so that light exits the light in a directional manner.
9. The light pipe of claim 8 , wherein the radial swath is less than about 180 degrees.
10. The light pipe of claim 9 , wherein the radial swath is more than about 10 degrees.
11. The light pipe of claim 9 , wherein the radial swath is less than about 90 degrees.
12. The light pipe of claim 8 , wherein the lumen output as between inlet and outlet portions of the active section is within plus or minus 10 percent of the average value of each other.
13. A light pipe with uniform side-light emission, comprising:
a) a core comprising an acrylic polymer and a fluoropolymer cladding on the core; the cladding having a lower refractive index than the core; and
b) light-scattering material being distributed in the core along an active section of the light pipe in which side-light emission is desired;
c) the light-scattering material being distributed substantially only in a radial swath, along the longitudinal axis of the light pipe, of less than about 180 degrees, so that light exits the light pipe in a directional manner.
14. The light pipe of claim 13 , wherein the light-scattering material comprises titanium dioxide particles.
15. The light pipe of claim 14 , wherein the radial swath is between about 30 and 45 degrees.
16. The light pipe of claim 15 , wherein the active section is between about 0.5 end 5 meters long.
17. The light pipe of claim 16 , wherein the active section is between about 1.5 and 2.5 meters long.
18. The light pipe of claim 16 , wherein the particles are distributed with a non-zero density gradient along a longitudinal axis of the light pipe chosen to result in uniform illumination along the active section.
19. The light pipe of claim 18 , wherein the lumen output as between inlet and outlet portions of the active section is within plus or minus 10 percent of the average value of each other.
20. A light pipe with uniform side-light emission, comprising:
a) a core comprising a polymer and a fluoropolymer cladding on the core; the cladding having a lower refractive index than the core; and
b) light-scattering material distributed within the core along an active section of light pipe in which side-light emission is desired;
c) the light-scattering material being distributed with a non-zero density gradient along a longitudinal axis of the light pipe chosen to achieve uniform side-light emission; and
d) the light-scattering material being distributed in the core along the active section of the light pipe, substantially only in a radial swath, along the longitudinal axis of the light pipe, of substantially less than 360 degrees, so that light exits the light pipe in a directional manner.
21. The light pipe of claim 20 , wherein the light-scattering material comprises titanium dioxide.