High transmission light control films with asymmetric light output
Light control films comprise a light input surface and alight output surface opposite the light input surface and alternating transmissive regions and absorptive regions disposed between the light input surface and the light output surface. The absorptive regions have an aspect ratio of at least 30 and are canted in the same direction. The alternating transmissive regions and absorbing regions have a maximum relative transmission at a viewing angle other than 0 degrees.
1. A light control film comprising:
a light input surface and a light output surface opposite the light input surface and a microstructured surface comprising a plurality of
alternating protrusions and channels disposed between the light input and output surfaces, each of the protrusions comprising opposing first and second sidewalls defining a plurality of alternating first and second sidewalls of the microstructured surface, a light absorbing material disposed on only on the first sidewalls to define a plurality of alternating transmissive regions and absorptive regions disposed between the light input surface and the light output surface, wherein the absorptive regions have an aspect ratio of at least 30 and are canted in the same direction, and the alternating transmissive regions and absorbing regions have a maximum relative transmission at a viewing angle other than 0 degrees.
2. The light control film of claim 1 wherein the alternating transmissive regions and absorbing regions have a maximum relative transmission at a viewing angle other than 0 degrees of at least 75%.
3. The light control film of claim 1 wherein the maximum relative transmission is at a viewing angle between +30 degrees and −30 degrees.
4. The light control film of claim 3 wherein the maximum relative transmission is at a viewing angle between +10 degrees and −10 degrees.
5. The light control film of claim 1 wherein the absorptive regions have a wall angle with a line that is perpendicular to the light output surface from +1 degree to +10 degrees or from −1 degree to −10 degrees.
6. The light control film of claim 5 wherein the absorptive regions have a wall angle with a line that is perpendicular to the light output surface from +2 degrees to +8 degrees or from −2 degrees to −8 degrees relative to the light input surface.
7. The light control film of claim 1 wherein the absorptive regions are parallel to each other.
8. The light control film of claim 1 wherein the absorptive regions have an aspect ratio of at least 50.
9. The light control film of claim 8 wherein the absorptive regions have an aspect ratio of at least 100.
10. The light control film of claim 1 wherein the absorptive regions have an average pitch of 10 to 100 microns.
11. The light control film of claim 1 wherein the absorptive regions comprise an organic light absorbing material.
12. The light control film of claim 1 wherein the absorptive regions comprise carbon black.
13. The light control film of claim 1 wherein the absorptive regions comprise polyelectrolytes.
14. The light control film of claim 1 wherein the absorptive regions comprise a non-metallic light absorbing material.
15. The light control film of claim 1 wherein the absorptive regions comprise bilayers in the form of a polyelectric stack comprising an organic polymeric polyion and counterion comprising a light absorbing material.
16. The light control film of claim 1 wherein the absorptive regions comprise a layer-by-layer light absorptive coating.
17. The light control film of claim 1 wherein the alternating transmissive regions are integral with a land region.
18. The light control film of claim 1 wherein the absorptive regions comprise a core sandwiched between cladding layers.
19. A method of making a light control film comprising:
providing a microstructured film comprising a bottom surface and a microstructured surface opposite the bottom surface and a plurality of light transmissive regions alternated with channels, each of the light transmissive regions defined by a top surface and first and second sidewalls, the channels comprising bottom surfaces opposite the top surfaces of the light transmissive regions, wherein each of the first sidewalls has a wall angle with a line that is perpendicular to the light output surface from +1 degree to +10 degrees or from −1 degree to −10 degrees;
applying an organic light absorptive material to the microstructured surface; and
removing the applied light absorptive material from the top surfaces, the bottom surfaces and only first sidewall or the second sidewalls.