US 12,493,208 B2
High transmission light control film
Daniel J. Schmidt, Woodbury, MN (US); Kevin W. Gotrik, Hudson, WI (US); Nicholas A. Johnson, Burnsville, MN (US); Raymond J. Kenney, Woodbury, MN (US); Caleb T. Nelson, McKinney, TX (US); and Kenneth A. Epstein, St. Paul, MN (US)
Assigned to 3M INNOVATIVE PROPERTIES COMPANY, St. Paul, MN (US)
Filed by 3M INNOVATIVE PROPERTIES COMPANY, St. Paul, MN (US)
Filed on Feb. 19, 2024, as Appl. No. 18/444,975.
Application 18/444,975 is a continuation of application No. 18/064,644, filed on Dec. 12, 2022, granted, now 11,940,689.
Application 18/064,644 is a continuation of application No. 17/264,512, granted, now 11,550,183, issued on Jan. 10, 2023, previously published as PCT/IB2019/056489, filed on Jul. 30, 2019.
Claims priority of provisional application 62/713,462, filed on Aug. 1, 2018.
Prior Publication US 2024/0192544 A1, Jun. 13, 2024
Int. Cl. G02B 5/00 (2006.01); G02B 5/30 (2006.01); G02F 1/1335 (2006.01)
CPC G02F 1/133524 (2013.01) [G02B 5/003 (2013.01); G02B 5/305 (2013.01); G02B 2207/123 (2013.01)] 8 Claims
OG exemplary drawing
 
1. A method of making a light control film comprising:
providing a microstructured film comprising a plurality of light transmissive regions 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; applying one or more layers of a light absorptive cladding material, each layer having a concentration of light absorbing particles, to the surface; applying a layer of a light absorptive core material having a first concentration of light absorbing particles, C1, on the one or more layers of light absorptive cladding material; applying an additional one or more layers of a light absorptive cladding material, each additional layer having the concentration of light absorbing particles, on the layer of light absorptive core material; and removing at least a portion of the one or more layers of light absorptive cladding material, the layer of light absorptive core material and the additional one or more layers of light absorptive cladding material from the top surface of the light transmissive regions and bottom surface of the channels, resulting in a plurality of louvers comprising a core layer having an aspect ratio of at least 20 sandwiched between a first cladding layer and a second cladding layer; wherein the concentration of light absorbing materials in each of the one or more layers of a light absorptive cladding material and each of the additional one or more layers of a light absorptive cladding material is less than C1; and wherein the layer of light absorptive core material comprises 30 wt % to 100 wt % of the light absorbing particles, and the one or more layers of light absorptive cladding material and the additional one or more layers of light absorptive cladding material comprise 0.5 wt % to 50 wt % of the light absorbing particles.