US 12,001,097 B2
Edge-lit back light unit with improved efficiency
Kenneth L. Walker, Semora, NC (US); Bing Shen, Cary, NC (US); and Matthew K. Pope, Durham, NC (US)
Assigned to BrightView Technologies, Inc., Durham, NC (US)
Filed by BrightView Technologies, Inc., Durham, NC (US)
Filed on May 2, 2023, as Appl. No. 18/310,877.
Application 18/310,877 is a continuation of application No. 17/553,170, filed on Dec. 16, 2021, granted, now 11,668,975.
Claims priority of provisional application 63/214,730, filed on Jun. 24, 2021.
Claims priority of provisional application 63/127,325, filed on Dec. 18, 2020.
Prior Publication US 2023/0273479 A1, Aug. 31, 2023
This patent is subject to a terminal disclaimer.
Int. Cl. G02F 1/13357 (2006.01); F21V 8/00 (2006.01); G02F 1/1335 (2006.01)
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
OG exemplary drawing
 
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.