Methods of manufacturing polymer dispersed liquid crystal films

Patent metadata

Field	Value
Publication number	US-2022011609-A1
Application number	US-201917296285-A
Country	US
Kind code	A1
Filing date	Nov 26, 2019
Priority date	Nov 30, 2018
Publication date	Jan 13, 2022
Grant date	—

Abstract

A method of manufacturing a polymer dispersed liquid crystal, PDLC, film, the method comprising: forming a region of liquid polymer (206) on a substrate (212); depositing one or more liquid crystal, LC, formulations (214) into the liquid polymer; and thereafter curing (234) the liquid polymer (206) to thereby induce phase separation between the polymer (206) and the liquid crystal formulations (214), resulting in PDLC pixels (236) which are phase separated from the surrounding, cured polymer—thereby producing a PDLC film.

First claim

1 . A method of manufacturing a polymer dispersed liquid crystal, PDLC, film, the method comprising:
forming a region of liquid polymer on a substrate; depositing one or more liquid crystal, LC, formulations into the liquid polymer; and thereafter curing the liquid polymer to thereby induce phase separation between the polymer and the liquid crystal formulations.

2 . The method according to claim 1 , wherein curing and phase separation is performed at least partially by photo-polymerization.

3 . The method according to claim 1 , wherein curing and phase separation is performed at least partially by thermal curing.

4 . The method according to claim 1 , wherein the step of depositing one or more liquid crystal formulations comprises inkjet printing liquid crystal droplets from a print head into the liquid polymer.

5 . The method according to claim 4 , wherein the inkjet printing process is a drop-on-demand inkjet printing process, a continuous inkjet printing process or an electrohydrodynamic jet printing process.

6 . The method according to claim 1 , wherein the region of liquid polymer is a layer of liquid polymer, or alternatively a droplet of liquid polymer.

7 . The method according to claim 1 , wherein the liquid polymer is a thiolene-based optical adhesive.

8 . The method according to claim 1 , wherein a refractive index of the liquid polymer is selected to match a refractive index of the liquid crystal formulations.

9 . The method according to claim 1 , further comprising the step of monitoring the formation and deposition of the liquid crystal formulations using a video camera, optionally in a shadowgraphy configuration.

10 . The method according to claim 2 , further comprising performing thermal curing after photo-polymerization and/or applying an external electric field to the substrate during the step of photo-polymerization.

11 . (canceled)

12 . The method according to claim 1 , further comprising positioning a top substrate over the polymer after the step of curing.

13 . The method according to claim 1 , further comprising, after the step of curing, coating the region of polymer with a conductive polymer and, optionally, affixing electrodes to the conductive polymer.

14 . The method according to claim 1 , wherein the region of liquid polymer is deposited by a thin-film deposition technique or inkjet printing process.

15 . The method according to claim 1 , wherein the LC formulations comprise one or more of the following:
nematic liquid crystals; chiral nematic liquid crystals; smectic liquid crystals; blue phase liquid crystals; and/or reactive mesogens.

16 . The method according to claim 1 , wherein the LC formulations further comprise one or more of the following:
one or more colour dyes; additional particles to increase light scattering properties; ionic dopants; and/or surfactants to improve printability of the LC formulations.

17 . A method of manufacturing a polymer dispersed liquid crystal, PDLC, film, the method comprising:
inkjet printing a mixture comprising a liquid polymer and liquid crystal, LC, formulations onto a substrate; and thereafter curing the liquid polymer to thereby induce phase separation between the polymer and the liquid crystal formulations.

18 . The method according to claim 17 , wherein said mixture is inkjet-printed to form a substantially even layer on the substrate.

19 . The method according to claim 17 , wherein said mixture is printed at discrete locations on the substrate to form localized sessile droplets.

20 . The method according to claim 19 , wherein said step of curing forms PDLC droplets with micron-sized domains or nano-sized domains.

21 . (canceled)

22 . The method according to claim 19 , wherein said step of curing forms encapsulated LC droplets.

Assignees

• Univ Oxford Innovation Ltd

Inventors

• Parry Ellis
• Morris Stephen
• Elston Steve
• Castrejón-Pita Alfonso

Classifications

• G02F1/13415

  Drop filling process · CPC title

• G02F1/1334 Primary

  based on polymer dispersed liquid crystals, e.g. microencapsulated liquid crystals · CPC title