DIFFUSER FILM WITH CONTROLLED LIGHT COLLIMATION
In one embodiment, a diffuser film with controlled light collimation comprises: a plastic layer having a first side and a second side, the first side having a first textured surface, wherein 20 to 50 percent of slope angles on the first textured surface proximate a first axis have a value of zero to five degrees. In one embodiment, a back lighted device, comprises: a light source, a light guide disposed proximate the light source for receiving light from the light source, and the diffuser film. In one embodiment, a method of controlling collimation in a diffusing film, comprises: determining a desired degree of collimation of the diffusing film; and texturing a plastic layer to form a first textured surface, wherein 20 to 50 percent of slope angles on the first textured surface proximate a first axis have a value of zero to five degrees.
1 . A diffuser film with controlled light collimation, comprising:
a plastic layer having a first side and a second side opposite the first side and a first peripheral edge, the first side having a first textured surface comprising projecting portions and/or trough portions, wherein 20 to 50 percent of slope angles on the first textured surface proximate a first axis have a value of greater than zero to five degrees; wherein the projecting portions and/or the trough portions have an average width of 20 μm to 100 μm.
2 . The diffuser film of claim 1 , wherein the first textured surface comprises a plurality of projecting portions and a plurality of trough portions, wherein each projecting portion extends outwardly from an adjacent trough portion.
3 . The diffuser film of claim 2 , wherein an average height of the plurality of projecting portions is 5 to 25 percent of an average width of the plurality of projecting portions.
4 . The diffuser film of claim 2 , wherein the average width of the plurality of projecting portions is 20 to 45 micrometers.
5 . The diffuser film of claim 1 , wherein the plastic layer controls collimation of light propagating through the plastic layer from the second side to the first side.
6 . The diffuser film of claim 1 , wherein the plastic layer controls collimation of light passing therethrough toward an axis perpendicular to a surface of the plastic layer.
7 . The diffuser film of claim 1 , wherein the second side comprises a second textured surface, wherein greater than or equal to 70 percent of slope angles on the second textured surface have a value of zero to five degrees.
8 . The diffuser film of claim 1 , wherein the plastic layer contains an optical brightener in a range of 0.001-1.0 percent of a total mass of the plastic layer.
9 . (canceled)
10 . The diffuser film of claim 1 , wherein the plastic layer comprises a fluorinated phosphonium sulfonate.
11 . The diffuser film of claim 10 , wherein the plastic layer further comprises a UV absorber compound in an amount of 0.01 to 1.0 percent of a total mass of the plastic layer.
12 . The diffuser film of claim 1 , wherein the plastic layer has a thickness of 0.025 millimeters to 10 millimeters.
13 . The diffuser film of claim 12 , wherein the thickness is 0.025 millimeters to 2 millimeters.
14 . The diffuser film of claim 1 , wherein greater than or equal to 80 percent of a total mass of the plastic layer comprises a polycarbonate compound.
15 . The diffuser film of claim 1 , wherein the plastic layer contains an optical brightener in a range of 0.001-1.0 percent of a total mass of the plastic layer.
16 . The diffuser film of claim 1 , wherein an internal stress in the plastic layer expressed in terms of optical retardation is less than or equal to 50 nanometers.
17 . The diffuser film of claim 1 , wherein the plastic layer has haze value greater than or equal to 80%.
18 . The diffuser film of claim 1 , wherein 20 to 50 percent of slope angles on the first textured surface proximate a second axis have a value of zero to five degrees, and wherein the second axis is substantially perpendicular to the first axis.
19 . A diffuser film with controlled light collimation comprising:
a unitary layer wherein greater than or equal to 80 percent of a total mass of the unitary layer comprises a polycarbonate compound, the unitary layer having a first side and a second side opposite the first side and a first peripheral edge, the first side having a first textured surface comprising projecting portions and/or trough portions, wherein 20 to 50 percent of slope angles on the first textured surface proximate a first axis have a value of greater than zero to five degrees, the first axis being substantially parallel to the first peripheral edge, wherein the plastic layer controls collimation of light propagating therethrough; and wherein the projecting portions and/or the trough portions have an average width of 20 μm to 100 μm.
20 . A back lighted device, comprising:
a light source;
a light guide disposed proximate the light source for receiving light from the light source; and
user film of claim 1 .
21 . The back lighted device of claim 20 , further comprising a light directing film disposed proximate the first textured surface.
22 . A method of controlling collimation in a diffusing film, comprising:
determining a desired degree of collimation for the diffusing film;
forming a plastic layer having a first side and a second side opposite the first side and a first peripheral edge, and
texturing the first side to form a first textured surface comprising projecting portions and/or trough portions, wherein 20 to 50 percent of slope angles on the first textured surface proximate a first axis have a value of greater than zero to five degrees, wherein the projecting portions and/or the trough portions have an average width of 20 μm to 100 μm.
23 . The diffuser film of claim 1 , wherein the plastic layer is configured to attain controlled light collimation using the textured surface and without using additional material.