发明人：
ASPELL, JENNIFER | WALKER, KENNETH L. | SHEN, BING
摘要：
A light transmissive substrate for transforming a Lambertian light distribution includes a base film having a first side and a second side opposite the first side, a plurality of first microstructures disposed on the first side of the base film and a plurality of first valleys. Each of the first valleys is defined by a pair of adjacent first microstructures. A filler material is disposed in the plurality of first valleys and defines a substantially planar surface spaced from and substantially parallel to the first side of the base film. The substrate also includes a plurality of second microstructures disposed on the substantially planar surface of the filler material and a plurality of second valleys. Each of the second valleys is defined by a pair of adjacent second microstructures.
权利要求：
WHAT IS CLAIMED IS:
1. A light transmissive substrate for transforming a Lambertian light
distribution, the light transmissive substrate comprising:
a base film having a first side and a second side opposite the first side;
a plurality of first microstructures disposed on the first side of the base film, each of the first microstructures having a first peak defining a first roof angle;
a plurality of first valleys, each of the first valleys defined by a pair of adjacent first microstructures;
a filler material disposed in the plurality of first valleys and defining a substantially planar surface spaced from and substantially parallel to the first side of the base film; and
a plurality of second microstructures disposed on the substantially planar surface of the filler material, each of the second microstructures having a second peak defining a second roof angle; and
a plurality of second valleys, each of the second valleys defined by a pair of adjacent second microstructures.
2. The light transmissive substrate according to claim 1 , wherein each of the plurality of first microstructures and the plurality of second microstructures is an elongated microprism having a triangular cross-section.
3. The light transmissive substrate according to claim 2, wherein the plurality of first microstructures and the plurality of second microstructures are orthogonal to each other.
4. The light transmissive substrate according to claim 1 , wherein the first roof angle is between about 50 degrees and about 70 degrees.
5. The light transmissive substrate according to claim 4, wherein the first roof angle is about 60 degrees.
6. The light transmissive substrate according to claim 1 , wherein the second roof angle is between about 70 degrees and about 90 degrees.
7. The light transmissive substrate according to claim 6, wherein the second roof angle is about 80 degrees.
8. The light transmissive substrate according to claim 1 , wherein the filler material has a refractive index of between about 1.3 and about 1.5.
9. The light transmissive substrate according to claim 8, wherein the refractive index is about 1.3.
10. The light transmissive substrate according to claim 1 , wherein the plurality of first microstructures and the plurality of second microstructures have refractive indices of between about 1.5 and about 1.7.
11. The light transmissive substrate according to claim 10, wherein the refractive indices are about 1.6.
12. The light transmissive substrate according to claim 1 , wherein the second side of the base film is substantially planar.
13. The light transmissive substrate according to claim 1 , wherein the second side of the base film comprises a texture.
14. A method for manufacturing a light transmissive substrate for transforming a Lambertian light distribution, the method comprising:
creating a plurality of first microstructures and a plurality of first valleys on a first side of a base film, each of the plurality of first microstructures having a first peak defining a first roof angle, and each of the plurality of first valleys being defined by an adjacent pair of first microstructures;
disposing a filler material in the plurality of first valleys to establish a substantially planar surface spaced from and substantially parallel to the first side of the base film; and
creating a plurality of second microstructures and a plurality of second valleys on the substantially planar surface of the filler material, each of the plurality of second microstructures having a second peak defining a second roof angle, and each of the plurality of second valleys being defined by an adjacent pair of second microstructures.
15. The method according to claim 14, further comprising curing the filler material before creating the plurality of second microstructures and the plurality of second valleys.
16. The method according to claim 14, wherein each of the plurality of first microstructures and the plurality of second microstructures is an elongated microprism having a triangular cross-section.
17. The method according to claim 16, wherein the plurality of second microstructures are orthogonal to the plurality of first microstructures.
18. The method according to claim 14, wherein the first roof angle is between about 50 degrees and about 70 degrees.
19. The method according to claim 18, wherein the first roof angle is about 60 degrees.
20. The method according to claim 14, wherein the second roof angle is between about 70 degrees and about 90 degrees.
21. The method according to claim 20, wherein the second roof angle is about 80 degrees.
22. The method according to claim 14, wherein the filler material has a refractive index of between about 1.3 and about 1.5.
23. The method according to claim 22, wherein the refractive index is about 1.3.
24. The method according to claim 14, wherein the plurality of first
microstructures and the plurality of second microstructures have refractive indices of between about 1.5 and about 1.7.
25. The method according to claim 24, wherein the refractive indices are about
1 .6.
26. The method according to claim 14, further comprising texturing the second side of the base film.