IP Library › Granted Patent US 12,228,818
Granted Patent B2
US 12,228,818 · App. 18/733,419 · Granted Feb 18, 2025

Back light unit for backlit displays

Inventors: Kenneth L. Walker (Semora, NC); Matthew K. Pope (Durham, NC)
Assignee: BrightView Technologies, Inc.
G02F1/133603G02F1/133605G02F1/133607G02F1/133611G02F1/13362G02F2202/022G02F2202/13
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Quick Facts
Patent No.
US 12,228,818
App. No.
18/733,419
Granted
Feb 18, 2025
Kind
B2
Abstract

A BLU includes a 2D array of LEDs, wherein a number of rows in the two-dimensional array is less than a number of columns in the two-dimensional array, and at least one LED in the two-dimensional array produces light with an angular distribution of nominally ±90 degrees around a center of the at least one LED. A transparent solid material layer is positioned with a bottom surface over the 2D array of LEDs that is configured to transform the light produced by the 2D array of LEDs into light having an angular distribution of nominally less than ±90 degrees around the center of the at least one LED at a top surface of the transparent solid material layer. A diffuser film is positioned over the top surface of the transparent solid material layer and is configured to provide a FWHM of greater than 60 degrees and configured to diffuse the light produced at the top surface of the transparent solid material layer to produce diffused light at a top surface of the diffuser film. A pair of cross BEFs is positioned over the top surface of the diffuser film and includes a plurality of prism microstructures where at least some prism microstructures have an apex angle of approximately ninety degrees. A polarizer reflector film is positioned over the pair of cross BEF and is configured to transmit one polarization and to reflect another polarization.

Claims (10)

1. A back light unit comprising:

a) a two-dimensional array of light emitting diodes (LEDs), wherein a number of rows in the two-dimensional array is less than a number of columns in the two-dimensional array, at least one LED in the two-dimensional array producing light with an angular distribution of nominally ±90 degrees around a center of the at least one LED;

b) a transparent solid material layer positioned with a bottom surface over the two-dimensional array of LEDs, the transparent solid material layer configured to transform the light produced by the two-dimensional array of LEDs into light having an angular distribution of nominally less than ±90 degrees around the center of the at least one LED at a top surface of the transparent solid material layer;

c) a diffuser film positioned over the top surface of the transparent solid material layer, the diffuser film configured to provide a full width at half max of greater than 60 degrees and configured to diffuse the light produced at the top surface of the transparent solid material layer to produce diffused light at a top surface of the diffuser film;

d) a pair of cross brightness enhancement films positioned over the top surface of the diffuser film and comprising a plurality of prism microstructures on at least one surface, at least some prism microstructures having an apex angle of approximately ninety degrees; and

e) a polarizer reflector film positioned over the pair of cross brightness enhancement films and configured to transmit one polarization and to reflect another polarization, thereby improving uniformity of the light output from the back light unit.

2. The back light unit of claim 1 , further comprising a second diffuser film positioned between the diffuser film and the pair of cross brightness enhancement films.

3. The back light unit of claim 1 , further comprising a prismatic angle bend film positioned over the polarizer reflector film and configured to tilt a light distribution from the output of the back light unit.

4. The back light unit of claim 1 , further comprising an elliptical diffuser film positioned over the polarizer reflector film and configured to broaden a light distribution for the output of the back light unit in one direction.

5. The back light unit of claim 1 , wherein a number of rows of the plurality of rows is less than or equal to fifteen.

Continuity (3)
Division 18418311 · Jan 21, 2024
Provisional Application 63503517 · May 22, 2023
Related Publication 20240393639A1 · Nov 28, 2024
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