# US 11,441,756 B2 · Vertically integrated transmissive microstructures for transforming light having Lambertian distribution

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- Number: US 11,441,756 B2
- Document ID: US11441756B2
- Status: Granted
- Kind: B2
- Application number: 16/973,689
- Filed: 2019-06-13
- Published: 2021-07-29
- Granted: 2022-09-13
- Earliest claimed: 2018-06-22
- Assignees: BrightView Technologies, Inc.
- Applicants: Brightview Technologies, Inc.
- Inventors: Jennifer Aspell; Kenneth L. Walker; Bing Shen
- Web page: https://patentgrep.com/patent/US11441756B2

## CPC

- F21V 5/005: {using microprisms}
- F21K 9/65: specially adapted for changing the characteristics or the distribution of the light, e.g. by adjustment of parts
- F21K 9/68: Details of reflectors forming part of the light source
- F21K 9/90: Methods of manufacture
- F21V 5/02: of prismatic shape (F21V5/04 takes precedence)
- G02B 5/045: {Prism arrays}
- G02B 19/0009: {having refractive surfaces only}
- G02B 19/0061: {the light source comprising a LED}
- F21Y 2115/10: Light-emitting diodes [LED]
- F21V: FUNCTIONAL FEATURES OR DETAILS OF LIGHTING DEVICES OR SYSTEMS THEREOF; STRUCTURAL COMBINATIONS OF LIGHTING DEVICES WITH OTHER ARTICLES, NOT OTHERWISE PROVIDED FOR
- F21K: NON-ELECTRIC LIGHT SOURCES USING LUMINESCENCE; LIGHT SOURCES USING ELECTROCHEMILUMINESCENCE; LIGHT SOURCES USING CHARGES OF COMBUSTIBLE MATERIAL; LIGHT SOURCES USING SEMICONDUCTOR DEVICES AS LIGHT-GENERATING ELEMENTS; LIGHT SOURCES NOT OTHERWISE PROVIDED FOR
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- F21Y: INDEXING SCHEME ASSOCIATED WITH SUBCLASSES F21K, F21L, F21S and F21V, RELATING TO THE FORM OR THE KIND OF THE LIGHT SOURCES OR OF THE COLOUR OF THE LIGHT EMITTED

## Abstract

A light transmissive substrate for transforming a Lambertian light distribution includes a base film having a first side and a second side opposite the first side, a plurality of first microstructures disposed on the first side of the base film and a plurality of first valleys. Each of the first valleys is defined by a pair of adjacent first microstructures. A filler material is disposed in the plurality of first valleys and defines a substantially planar surface spaced from and substantially parallel to the first side of the base film. The substrate also includes a plurality of second microstructures disposed on the substantially planar surface of the filler material and a plurality of second valleys. Each of the second valleys is defined by a pair of adjacent second microstructures.

## Claims

### Claim 1

A light transmissive substrate for transforming a Lambertian light distribution, the light transmissive substrate comprising:
a base film having a first side and a second side opposite the first side;
a plurality of first microstructures disposed on the first side of the base film, each of the first microstructures having a first peak defining a first roof angle;
a plurality of first valleys, each of the first valleys defined by a pair of adjacent first microstructures;
a filler material disposed in the plurality of first valleys and defining a substantially planar surface spaced from and substantially parallel to the first side of the base film; and
a plurality of second microstructures disposed on the substantially planar surface of the filler material, each of the second microstructures having a second peak defining a second roof angle; and
a plurality of second valleys, each of the second valleys defined by a pair of adjacent second microstructures.

### Claim 2 (depends on 1)

The light transmissive substrate according to claim 1, wherein each of the plurality of first microstructures and the plurality of second microstructures is an elongated microprism having a triangular cross-section.

### Claim 3 (depends on 2)

The light transmissive substrate according to claim 2, wherein the plurality of first microstructures and the plurality of second microstructures are orthogonal to each other.

### Claim 4 (depends on 1)

The light transmissive substrate according to claim 1, wherein the first roof angle is between about 50 degrees and about 70 degrees.

### Claim 5 (depends on 4)

The light transmissive substrate according to claim 4, wherein the first roof angle is about 60 degrees.

### Claim 6 (depends on 1)

The light transmissive substrate according to claim 1, wherein the second roof angle is between about 70 degrees and about 90 degrees.

### Claim 7 (depends on 6)

The light transmissive substrate according to claim 6, wherein the second roof angle is about 80 degrees.

### Claim 8 (depends on 1)

The light transmissive substrate according to claim 1, wherein the filler material has a refractive index of between about 1.3 and about 1.5.

### Claim 9 (depends on 8)

The light transmissive substrate according to claim 8, wherein the refractive index is about 1.3.

### Claim 10 (depends on 1)

The light transmissive substrate according to claim 1, wherein the plurality of first microstructures and the plurality of second microstructures have refractive indices of between about 1.5 and about 1.7.

### Claim 11 (depends on 10)

The light transmissive substrate according to claim 10, wherein the refractive indices are about 1.6.

### Claim 12 (depends on 1)

The light transmissive substrate according to claim 1, wherein the second side of the base film is substantially planar.

### Claim 13 (depends on 1)

The light transmissive substrate according to claim 1, wherein the second side of the base film comprises a texture.

### Claim 14

A method for manufacturing a light transmissive substrate for transforming a Lambertian light distribution, the method comprising:
creating a plurality of first microstructures and a plurality of first valleys on a first side of a base film, each of the plurality of first microstructures having a first peak defining a first roof angle, and each of the plurality of first valleys being defined by an adjacent pair of first microstructures;
disposing a filler material in the plurality of first valleys to establish a substantially planar surface spaced from and substantially parallel to the first side of the base film; and
creating a plurality of second microstructures and a plurality of second valleys on the substantially planar surface of the filler material, each of the plurality of second microstructures having a second peak defining a second roof angle, and each of the plurality of second valleys being defined by an adjacent pair of second microstructures.

### Claim 15 (depends on 14)

The method according to claim 14, further comprising curing the filler material before creating the plurality of second microstructures and the plurality of second valleys.

### Claim 16 (depends on 14)

The method according to claim 14, wherein each of the plurality of first microstructures and the plurality of second microstructures is an elongated microprism having a triangular cross-section.

### Claim 17 (depends on 16)

The method according to claim 16, wherein the plurality of second microstructures are orthogonal to the plurality of first microstructures.

### Claim 18 (depends on 14)

The method according to claim 14, wherein the first roof angle is between about 50 degrees and about 70 degrees.

### Claim 19 (depends on 18)

The method according to claim 18, wherein the first roof angle is about 60 degrees.

### Claim 20 (depends on 14)

The method according to claim 14, wherein the second roof angle is between about 70 degrees and about 90 degrees.

### Claim 21 (depends on 20)

The method according to claim 20, wherein the second roof angle is about 80 degrees.

### Claim 22 (depends on 14)

The method according to claim 14, wherein the filler material has a refractive index of between about 1.3 and about 1.5.

### Claim 23 (depends on 22)

The method according to claim 22, wherein the refractive index is about 1.3.

### Claim 24 (depends on 14)

The method according to claim 14, wherein the plurality of first microstructures and the plurality of second microstructures have refractive indices of between about 1.5 and about 1.7.

### Claim 25 (depends on 24)

The method according to claim 24, wherein the refractive indices are about 1.6.

### Claim 26 (depends on 14)

The method according to claim 14, further comprising texturing the second side of the base film.