High transmission light control film comprising alternating transmissive and absorptive regions

Patent metadata

Field	Value
Publication number	US-12313864-B2
Application number	US-202017757743-A
Country	US
Kind code	B2
Filing date	Dec 18, 2020
Priority date	Dec 23, 2019
Publication date	May 27, 2025
Grant date	May 27, 2025

Abstract

A light control film comprises a light input surface and a light output surface; alternating transmissive regions and absorptive regions disposed between the light input surface and the light output surface; and TIR cladding layers. The TIR cladding layer having a refractive index, n TIR . The transmissive regions alternate between high refractive index transmissive regions having a refractive index, n 2 , and low refractive index transmissive regions having a refractive index, n 1 . The absorptive regions comprise a core having a refractive index, n core , adjacent an AR cladding layer; wherein n 1 <n 2 and n TIR <n 2 . The TIR cladding layers are adjacent the high refractive index transmissive regions. The cores have an aspect ratio of at least 20. The high refractive index transmissive regions have a wall angle of 6 degrees or less.

First claim

We claim:

1. A light control film comprising:
a light input surface and a light output surface opposite the light input surface;
alternating transmissive regions and absorptive regions disposed between the light input surface and the light output surface; and
TIR cladding layers, the TIR cladding layer having a refractive index, n TIR , and an extinction coefficient, K TIR ;
wherein the transmissive regions alternate between high refractive index transmissive regions having a refractive index, n 2 , and low refractive index transmissive regions having a refractive index, n 1 ,
wherein the absorptive regions comprise a core having a refractive index, ncore, and an extinction coefficient, k core , adjacent an AR cladding layer, the AR cladding layer having a refractive index, n AR , and an extinction coefficient, K AR ;
wherein n 1 <n 2 ;
wherein n TIR <n 2 ;
wherein the TIR cladding layers are adjacent the high refractive index transmissive regions;
wherein the cores have an aspect ratio of at least 20; and
wherein the high refractive index transmissive regions have a wall angle of 6 degrees or less.

2. The light control film of claim 1 wherein k TIR <k core and K AR <K core .

3. The light control film of claim 2 wherein k TIR <K AR .

4. The light control film of claim 1 wherein the cores, TIR cladding layers and AR cladding layers comprise light absorbing particles.

5. The light control film of claim 4 wherein the light absorbing particles comprise carbon black.

6. The light control film of claim 1 wherein K TIR is 0 to 0.1.

7. The light control film of claim 1 wherein k AR is 0.005 to 0.15.

8. The light control film of claim 1 wherein K core is 0.1 to 0.5.

9. A light control film comprising:
a light input surface and a light output surface opposite the light input surface;
alternating transmissive regions and absorptive regions disposed between the light input surface and the light output surface; and
TIR cladding layers, the TIR cladding layer having a refractive index, n TIR , and a concentration of light absorbing material, C TIR ;
wherein the transmissive regions alternate between high refractive index transmissive regions having a refractive index, n 2 , and low refractive index transmissive regions having a refractive index, n 1 ,
wherein the absorptive regions comprise a core having a refractive index, n core , and a concentration of light absorbing material, C core , adjacent an AR cladding layer, the AR cladding layer having a refractive index, n AR , and a concentration of light absorbing material, C AR ;
wherein n 1 <n 2 ;
wherein n TIR <n 2 ;
wherein the TIR cladding layers are adjacent the high refractive index transmissive regions;
wherein the cores have an aspect ratio of at least 20; and
wherein the high refractive index transmissive regions have a wall angle of 6 degrees or less.

10. The light control film of claim 9 wherein C TIR <C core and C AR <C core .

11. The light control film of claim 10 wherein C TIR <C AR .

12. The light control film of claim 1 wherein the cores, TIR cladding layers and AR cladding layers comprise light absorbing particles.

13. The light control film of claim 12 wherein the light absorbing particles comprise carbon black.

14. The light control film of claim 9 wherein the TIR cladding layers comprise 0 wt. % to 40 wt. % of light absorbing material.

15. The light control film of claim 9 wherein the AR cladding layers comprise 25 wt. % to 45 wt. % of light absorbing material.

16. The light control film of claim 1 the cores comprise 30 wt. % to 100 wt. % of light absorbing material.

17. The light control film of claim 1 wherein n 1 is 1.47-1.55.

18. The light control film of claim 1 wherein n 2 is 1.6 to 1.7.

19. A method of making a light control film comprising:
providing a microstructured film comprising a plurality of high refractive index transmissive regions having a refractive index, n 2 , alternated with channels, wherein the microstructured film has a surface defined by a top surface and side walls of the light transmissive regions and a bottom surface of the channels, wherein the side walls have a wall angle of 6 degrees or less;
applying a TIR layer of a light absorptive or transmissive cladding material having a refractive index, n TIR , and an extinction coefficient, K TIR , to the surface;
applying a layer of a light absorptive core material having a refractive index, n core , and an extinction coefficient, k core , on the TIR layer;
applying an AR layer of a light absorptive cladding material having a refractive index, n AR , and an extinction coefficient, k AR , on the layer of light absorptive core material;
removing at least a portion of the TIR layer, the layer of light absorptive core material and the AR layer from the top surface of the light transmissive regions and bottom surface of the channels; and
filling the channels with a light transmissive organic polymeric material having a refractive index, n 1 ;
wherein n 1 <n 2 and n TIR <n 2 .

20. A method of making a light control film comprising:
providing a microstructured film comprising a plurality of high refractive index transmissive regions having a refractive index, n 2 , alternated with channels, wherein the microstructured film has a surface defined by a top surface and side walls of the light transmissive regions and a bottom surface of the channels, wherein the side walls have a wall angle of 6 degrees or less;
applying a TIR layer of a light absorptive or transmissive cladding material having a refractive index, n TIR , and a concentration of light absorbing material, C TIR , to the surface;
applying a layer of a light absorptive core material having a refractive index, n core , and a concentration of light absorbing material, C core , on the TIR layer;
applying an AR layer of a light absorptive cladding material having a refractive index, n AR , and a concentration of light absorbing material, C AR , on the layer of light absorptive core material;
removing at least a portion of the TIR layer, the layer of light absorptive core material and the AR layer from the top surface of the light transmissive regions and bottom surface of the channels; and
filling the channels with a light transmissive organic polymeric material having a refractive index, n 1 ;
wherein n 1 <n 2 and n TIR <n 2 .

Assignees

• 3M Innovative Properties Company

Inventors

• Liu Tao
• Johnson Nicholas A
• Kenney Raymond J
• Nelson Caleb T
• Schmidt Daniel J

Classifications

• G02B5/3033

  in the form of a thin sheet or foil, e.g. Polaroid · CPC title

• G02B5/28

  Interference filters · CPC title

• G02B1/04

  made of organic materials, e.g. plastics (G02B1/08 takes precedence) · CPC title

• G02B2207/123

  Optical louvre elements, e.g. for directional light blocking · CPC title

• G02B5/003 Primary

  Light absorbing elements · CPC title