| CPC G02B 6/0068 (2013.01) [G02B 6/0016 (2013.01); G02B 6/0025 (2013.01); G02B 6/0073 (2013.01)] | 20 Claims |
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1. A backlight for providing illumination along a first direction to a display disposed thereon, the backlight comprising:
a plurality of spaced apart discrete light sources arranged in rows and columns of the light sources and configured to face the display; and
an optical film disposed on and above the light sources and below and proximate a first plane, the optical film and the first plane configured to be disposed between the display and the light sources, the optical film comprising a plurality of through-holes arranged in rows and columns of the through-holes and extending between first and second major surfaces of the optical film, each through hole having a first opening at the first major surface and having a first open area, A1, and a second opening at the second major surface and having a second open area, A2, each through-hole having a length, H, along the first direction such that the ratio of H/A2 is greater than or equal to about 0.13, such that:
when all the light sources emit light, the light emitted by all the light sources has a first overall peak intensity in the first plane, and a first brightness uniformity across the first plane, and
in the absence of the optical film, the light emitted by all the light sources has a second overall peak intensity in the first plane, and a second brightness uniformity across the first plane, wherein:
the first and second overall peak intensities are different by less than about 20%; and
the first brightness uniformity exhibits an improvement over the second brightness uniformity by at least 2.8%.
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