High transmission light control film
A light control film comprises a light input surface and a light output surface opposite the light input surface; alternating transmissive regions and absorptive regions disposed between the light input surface and the light output surface, wherein the absorptive regions comprise a core having a first concentration, C 1 , of a light absorbing material sandwiched between cladding layers having a second concentration, C 2 , of the light absorbing material, wherein C 2 <C 1 , and wherein the cores have an aspect ratio of at least 20.
1. A light control film comprising:
a light input surface and a light output surface opposite the light input surface;
alternating transmissive regions and absorptive regions disposed between the light input surface and the light output surface, wherein the absorptive regions comprise a core having a first extinction coefficient, k 1 , sandwiched between cladding layers having a second extinction coefficient, k 2 , wherein k 2 <k 1 , and wherein the cores have an aspect ratio of at least 20,
wherein the core comprises 30 wt. % to 100 wt. % of a light absorbing material and the cladding layers comprise 0.5 wt. % to 50 wt. % of the light absorbing material.
2. The light control film of claim 1 wherein the core and the cladding layers comprise light absorbing material comprising light absorbing particles.
3. The light control film of claim 1 wherein the core and the cladding layers comprise organic light absorbing material.
4. The light control film of claim 1 wherein the core and the cladding layers comprise carbon black particles.
5. The light control film of claim 1 wherein the core and the cladding layers comprise light absorbing particles having a median particle size less than about 500 nanometers.
6. The light control film of claim 1 wherein k 1 is 0.2-0.4 and k 2 is 0.005-0.15.
7. The light control film of claim 1 wherein the cladding layers comprise light absorbing particles, non-light absorbing diluent and an organic polymeric material.
8. The light control film of claim 7 wherein the non-light absorbing diluent comprises silica particles.
9. The light control film of claim 1 wherein the transmissive regions have a wall angle less than 5 degrees.
10. The light control film of claim 1 wherein the transmissive regions and absorptive regions have a height ranging from 40 microns to 400 microns.
11. The light control film of claim 1 wherein the cores have an average width no greater than 5 microns.
12. The light control film of claim 1 wherein the cladding layers have an average width no greater than 1 micron.
13. The light control film of claim 12 wherein the cladding layers have an average width of 100 nm to 500 nm.
14. The light control film of claim 1 wherein the absorptive regions have an aspect ratio of at least 50.
15. The light control film of claim 1 wherein the transmissive regions have an aspect ratio of a least 2.
16. The light control film of claim 1 wherein absorptive regions have an average pitch of 10 microns to 400 microns.
17. The light control film of claim 1 wherein the light control film has a relative transmission at a viewing angle of 0 degrees of at least 75%.
18. The light control film of claim 1 wherein the light control film has an average relative transmission at viewing angles of 35 degrees to 80 degrees of no more than 5%.
19. The light control film of claim 1 wherein the cladding layers are conformal coatings on the cores.
20. A light control film comprising:
a light input surface and a light output surface opposite the light input surface;
alternating transmissive regions and absorptive regions disposed between the light input surface and the light output surface, wherein the absorptive regions comprise a core comprising light absorbing particles sandwiched between cladding layers comprising light absorbing particles and non-light absorbing diluent, and wherein the cores have an aspect ratio of at least 20,
wherein the core comprises 30 wt. % to 100 wt. % of a light absorbing material and the cladding layers comprise 0.5 wt. % to 50 wt. % of the light absorbing material.