Back to results
US 12,001,097 B2Granted
Edge-lit back light unit with improved efficiency
AssigneeBrightView Technologies, Inc.
InventorsKenneth L. Walker, Bing Shen, Matthew K. Pope
Life of this patent
Estimating the term…
Abstract
An edge-lit back light unit for a backlit display includes a reflector, an edge-lit light guide film, a diffuser film, and a pair of crossed brightness enhancement films with increased efficiency. The diffuser film has an angular light distribution output that is matched to light acceptance angles of the pair of crossed brightness enhancement films to provide increased on-axis brightness without having to increase power to the edge-lit back light unit.
Claims33
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.
2 more elements
An edge-lit back light unit for a backlit display, the edge-lit back light unit comprising:
- a) a diffusive reflector;
- b) an edge-lit light guide film positioned above the diffusive 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 diffusive 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.
2 more elements
A diffuser film for a back light unit comprising:
- a) a substrate;
- b) a plurality of parallel prism microstructures positioned on a bottom surface of the substrate, at least some of the plurality of parallel prism microstructures having an apex angle between 78° and 92° and a refractive index between 1.49 and 1.58, the plurality of parallel prism microstructures configured to receive light having a peak optical distribution between 15° and 20° and a full width half maximum angle of diffusion of between 25° to 45°;
- and
- c) a plurality of inverted pyramid microstructures positioned on a top surface of the substrate, at least some of plurality of the inverted pyramid microstructures having an apex angle between 80° and 110° and a refractive index between 1.49 and 1.7, the diffuser film providing light from the top surface having a peak optical distribution between 30° to 50° and a full width half maximum angle of diffusion of 55° to 85°.
1 more element
Dependencies are inferred from the claim text.