CPC G02F 1/133603 (2013.01) [G02B 6/0011 (2013.01); G02F 1/133524 (2013.01); G02F 1/133607 (2021.01); G02F 1/133615 (2013.01)] | 33 Claims |
1. An edge-lit back light unit for a backlit display, the edge-lit back light unit comprising:
a) a specular reflector;
b) an edge-lit light guide film positioned above the specular reflector, the edge-lit light guide film having a length and a width, wherein a combination of the edge-lit light guide film and the specular reflector is configured to couple light that is input at a light input edge of the edge-lit light guide film out of the edge-lit light guide film with an angular distribution that is directed away from the light input edge and runs nominally along the length of the edge-lit light guide film;
c) a diffuser film positioned above the edge-lit light guide film, the diffuser film having a plurality of parallel prism microstructures on one side thereof facing the edge-lit light guide film, at least some of the plurality of parallel prism microstructures having an apex angle and being formed of a material having a refractive index, and a plurality of inverted pyramid microstructures on an opposite side thereof, the inverted pyramid microstructures having an apex angle and being formed of a material having a refractive index; and
d) a pair of crossed brightness enhancement films positioned above the diffuser film, at least one of the brightness enhancement films having a plurality of parallel micro prisms on one side thereof and facing away from the diffuser film, wherein the plurality of parallel micro prisms of one of the brightness enhancement films is oriented perpendicular to the plurality of micro prisms of the other brightness enhancement film.
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