# US 12,111,530 B2 · Polymer-dispersed-type liquid crystal film, emulsion, and method for producing polymer-dispersed-type liquid crystal film

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- Number: US 12,111,530 B2
- Document ID: US12111530B2
- Status: Granted
- Kind: B2
- Application number: 17/916,208
- Filed: 2021-03-29
- Published: 2023-10-26
- Granted: 2024-10-08
- Earliest claimed: 2020-03-31
- Assignees: Nitto Denko Corporation
- Applicants: Nitto Denko Corporation
- Inventors: Hiroyuki Takemoto; Jin Yoshikawa; Masanori Otsuka; Mariko Hirai
- Web page: https://patentgrep.com/patent/US12111530B2

## CPC

- G02F 1/1334: based on polymer dispersed liquid crystals, e.g. microencapsulated liquid crystals
- B32B 27/08: of synthetic resin
- B32B 27/36: comprising polyesters
- B32B 37/24: with at least one layer not being coherent before laminating, e.g. made up from granular material sprinkled onto a substrate (B32B37/15 takes precedence)
- B32B 2037/243: {Coating}
- B32B 2250/02: 2 layers
- B32B 2250/244: All polymers belonging to those covered by group B32B27/36
- B32B 2255/10: on synthetic resin layer or on natural or synthetic rubber layer
- B32B 2255/20: Inorganic coating
- B32B 2255/26: Polymeric coating
- B32B 2255/28: Multiple coating on one surface
- B32B 2307/202: Conductive
- B32B 2307/412: Transparent
- B32B 2457/202: LCD, i.e. liquid crystal displays
- G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- B32B: LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM

## Abstract

According to the present invention, provided is a PDLC film, which includes a PDLC layer excellent in thickness uniformity and is suppressed from causing liquid crystal leakage from the PDLC layer. A method of producing a polymer dispersed liquid crystal film of the present invention includes: applying, to a first transparent conductive film, an emulsion including a solvent, and polymer particles and liquid crystal particles dispersed in the solvent to form an applied layer; drying the applied layer to form a polymer dispersed liquid crystal layer containing a polymer matrix and the liquid crystal particles dispersed in the polymer matrix; and laminating a second transparent conductive film on the polymer dispersed liquid crystal layer, wherein the polymer particles include first polymer particles and second polymer particles, and wherein an average particle diameter of the second polymer particles is larger than an average particle diameter of the first polymer particles.

## Claims

### Claim 1

A method of producing a polymer dispersed liquid crystal film, comprising:
applying, to a first transparent conductive film, an emulsion including a solvent, and polymer particles and liquid crystal particles dispersed in the solvent to form an applied layer;
drying the applied layer to form a polymer dispersed liquid crystal layer containing a polymer matrix and the liquid crystal particles dispersed in the polymer matrix; and
laminating a second transparent conductive film on the polymer dispersed liquid crystal layer,
wherein the polymer particles include first polymer particles and second polymer particles, and
wherein an average particle diameter of the second polymer particles is larger than an average particle diameter of the first polymer particles.

### Claim 2 (depends on 1)

The production method according to claim 1, wherein the average particle diameter of the second polymer particles is from 1.3 times to 20 times as large as the average particle diameter of the first polymer particles.

### Claim 3 (depends on 1)

The production method according to claim 1, wherein the average particle diameter of the first polymer particles is from 10 nm to 100 nm.

### Claim 4 (depends on 1)

The production method according claim 1, wherein the average particle diameter of the second polymer particles is from 50 nm to 500 nm.

### Claim 5 (depends on 1)

The production method according to claim 1, wherein the emulsion further includes a leveling agent and/or a cross-linking agent.

### Claim 6

An emulsion for forming a polymer dispersed liquid crystal layer, comprising:
a solvent; and
polymer particles and liquid crystal particles dispersed in the solvent,
wherein the polymer particles include first polymer particles and second polymer particles, and
wherein an average particle diameter of the second polymer particles is larger than an average particle diameter of the first polymer particles.

### Claim 7 (depends on 6)

The emulsion according to claim 6, wherein the average particle diameter of the second polymer particles is from 1.3 times to 20 times as large as the average particle diameter of the first polymer particles.

### Claim 8 (depends on 6)

The emulsion according to claim 6, wherein the average particle diameter of the first polymer particles is from 10 nm to 100 nm.

### Claim 9 (depends on 6)

The emulsion according to claim 6, wherein the average particle diameter of the second polymer particles is from 50 nm to 500 nm.

### Claim 10 (depends on 6)

The emulsion according to claim 6, further comprising a leveling agent and/or a cross-linking agent.

### Claim 11 (depends on 6)

A polymer dispersed liquid crystal film, comprising in this order:
a first transparent conductive film;
a polymer dispersed liquid crystal layer; and
a second transparent conductive film,
wherein the polymer dispersed liquid crystal layer is formed by applying the emulsion for forming a polymer dispersed liquid crystal layer of claim 6 to the first transparent conductive film, and drying the emulsion.

### Claim 12 (depends on 11)

The polymer dispersed liquid crystal film according to claim 11, wherein the polymer dispersed liquid crystal layer has a thickness of from 1 μm to 15 μm.