Liquid crystal composition, optical element, and light guide element

Patent metadata

Field	Value
Publication number	US-2024004116-A1
Application number	US-202318467447-A
Country	US
Kind code	A1
Filing date	Sep 14, 2023
Priority date	Mar 22, 2021
Publication date	Jan 4, 2024
Grant date	—

Abstract

Regarding an optical element that includes an optically-anisotropic layer having a liquid crystal alignment pattern where a direction of an optical axis derived from a liquid crystal compound changes while continuously rotating in at least one in-plane direction, an object of the present invention is to provide a liquid crystal composition with which an optical element having an excellent diffraction efficiency can be prepared, and an optical element and a light guide element. The liquid crystal composition according to the present invention includes a rod-like liquid crystal compound and a disk-like liquid crystal compound, and a ratio between a twist elastic constant K22 and a splay elastic constant K11 of the liquid crystal composition satisfies 0.7≤K22/K11.

First claim

What is claimed is:

1 . A liquid crystal composition comprising:
a liquid crystal compound, wherein the liquid crystal composition includes a rod-like liquid crystal compound and a disk-like liquid crystal compound, and a ratio between a twist elastic constant K22 and a splay elastic constant K11 of the liquid crystal composition satisfies 0.7≤K22/K11.

2 . The liquid crystal composition according to claim 1 ,
wherein a difference Δn 550 in refractive index generated by refractive index anisotropy of the liquid crystal composition is 0.2 or more.

3 . The liquid crystal composition according to claim 1 ,
wherein a content of the disk-like liquid crystal compound in the liquid crystal composition with respect to a total mass of the rod-like liquid crystal compound and the disk-like liquid crystal compound in the liquid crystal composition is 5 to 25 mass %.

4 . The liquid crystal composition according to claim 1 ,
wherein the rod-like liquid crystal compound is a compound represented by Formula (I),

in Formula (I),
P 1 and P 2 each independently represent a hydrogen atom or a substituent,
S 1 and S 2 each independently represent a single bond or a divalent linking group,
A 1 and A 2 each independently represent a non-aromatic ring, an aromatic ring, or an aromatic heterocycle which may have a substituent,
in a case where a plurality of A 2 's are present, the plurality of A 2 's may be the same as or different from each other,
Y 1 represents —O—, —S—, —OCH 2 —, —CH 2 O—, —CH 2 CH 2 —, —CO—, —COO—, —OCO—, —CO—S—, —S—CO—, —O—CO—O—, —CO—NH—, —NH—CO—, —SCH 2 —, —CH 2 S—, —CF 2 O—, —OCF 2 —, —CF 2 S—, —SCF 2 —, —CH═CH—COO—, —CH═CH—OCO—, —COO—CH═CH—, —OCO—CH═CH—, —COO—CH 2 CH 2 —, —OCO—CH 2 CH 2 —, —CH 2 CH 2 —COO—, —CH 2 CH 2 —OCO—, —COO—CH 2 —, —OCO—CH 2 —, —CH 2 —COO—, —CH 2 —OCO—, —CH═CH—, —N═N—, —CH═N—N═CH—, —CF═CF—, —C≡C—, —OCH 2 CH 2 O—, —SCH 2 CH 2 S—, or a single bond,
in a case where a plurality of Y 1 's are present, the plurality of Y 1 's may be the same as or different from each other, and
m1 represents an integer of 1 to 12.

5 . The liquid crystal composition according to claim 1 ,
wherein the disk-like liquid crystal compound is a compound represented by Formula (II),

in Formula (II),
P 3 represents a hydrogen atom or a substituent,
a plurality of P 3 's may be the same as or different from each other,
S 3 represents a single bond or a divalent linking group,
a plurality of S 3 's may be the same as or different from each other,
A 3 represent a non-aromatic ring, an aromatic ring, or an aromatic heterocycle which may have a substituent,
a plurality of A 3 's may be the same as or different from each other,
Y 2 represents —O—, —S—, —OCH 2 —, —CH 2 O—, —CH 2 CH 2 —, —CO—, —COO—, —OCO—, —CO—S—, —S—CO—, —O—CO—O—, —CO—NH—, —NH—CO—, —SCH 2 —, —CH 2 S—, —CF 2 O—, —OCF 2 —, —CF 2 S—, —SCF 2 —, —CH═CH—COO—, —CH═CH—OCO—, —COO—CH═CH—, —OCO—CH═CH—, —COO—CH 2 CH 2 —, —OCO—CH 2 CH 2 —, —CH 2 CH 2 —COO—, —CH 2 CH 2 —OCO—, —COO—CH 2 —, —OCO—CH 2 —, —CH 2 —COO—, —CH 2 —OCO—, —CH═CH—, —N═N—, —CH═N—N═CH—, —CF═CF—, —C≡C—, —OCH 2 CH 2 O—, —SCH 2 CH 2 S—, or a single bond,
a plurality of Y 2 's may be the same as or different from each other,
m2 represents an integer of 0 to 5,
n represents an integer of 3 to 20, and
D represents an n-valent disk-like core.

6 . The liquid crystal composition according to claim 4 ,
wherein at least one Y 1 in Formula (I) represents —C≡C—.

7 . An optical element comprising:
an optically-anisotropic layer that is formed of a liquid crystal composition including a liquid crystal compound, wherein the liquid crystal composition includes a rod-like liquid crystal compound and a disk-like liquid crystal compound, and the optically-anisotropic layer has a liquid crystal alignment pattern in which a direction of an optical axis derived from the liquid crystal compound changes while continuously rotating in at least one in-plane direction.

8 . An optical element comprising:
an optically-anisotropic layer that is formed of the liquid crystal composition according to claim 1 , wherein the liquid crystal composition includes a rod-like liquid crystal compound and a disk-like liquid crystal compound, and the optically-anisotropic layer has a liquid crystal alignment pattern in which a direction of an optical axis derived from the liquid crystal compound changes while continuously rotating in at least one in-plane direction.

9 . The optical element according to claim 7 ,
wherein the directions of the optical axes in the optically-anisotropic layer match each other in a thickness direction.

10 . The optical element according to claim 7 ,
wherein the optically-anisotropic layer has a region where the direction of the optical axis is twisted in a thickness direction and rotates.

11 . The optical element according to claim 7 ,
wherein in a case where a length over which the direction of the optical axis rotates by 180° in a plane is set as a single period, the optically-anisotropic layer has regions having different lengths of the single periods in the liquid crystal alignment pattern.

12 . The optical element according to claim 7 ,
wherein a single period in the liquid crystal alignment pattern gradually decreases in the one in-plane direction in which the direction of the optical axis changes while continuously rotating in the liquid crystal alignment pattern.

13 . The optical element according to claim 7 ,
wherein the liquid crystal alignment pattern of the optically-anisotropic layer is a concentric circular pattern having a concentric circular shape where the one in-plane direction in which the direction of the optical axis changes while continuously rotating moves from an inner side toward an outer side.

14 . Alight guide element comprising:
the optical element according to claim 7 ; and a light guide plate.

15 . The liquid crystal composition according to claim 2 ,
wherein a content of the disk-like liquid crystal compound in the liquid crystal composition with respect to a total mass of the rod-like liquid crystal compound and the disk-like liquid crystal compound in the liquid crystal composition is 5 to 25 mass %.

16 . The liquid crystal composition according to claim 2 ,
wherein the rod-like liquid crystal compound is a compound represented by Formula (I),

in Formula (I),
P 1 and P 2 each independently represent a hydrogen atom or a substituent,
S 1 and S 2 each independently represent a single bond or a divalent linking group,
A 1 and A 2 each independently represent a non-aromatic ring, an aromatic ring, or an aromatic heterocycle which may have a substituent,
in a case where a plurality of A 2 's are present, the plurality of A 2 's may be the same as or different from each other,
Y 1 represents —O—, —S—, —OCH 2 —, —CH 2 O—, —CH 2 CH 2 —, —CO—, —COO—, —OCO—, —CO—S—, —S—CO—, —O—CO—O—, —CO—NH—, —NH—CO—, —SCH 2 —, —CH 2 S—, —CF 2 O—, —OCF 2 —, —CF 2 S—, —SCF 2 —, —CH═CH—COO—, —CH═CH—OCO—, —COO—CH═CH—, —OCO—CH═CH—, —COO—CH 2 CH 2 —, —OCO—CH 2 CH 2 —, —

Assignees

• Fujifilm Corp

Inventors

• Okubo Megumi
• Ichihashi Mitsuyoshi
• Fukushima Yuki
• Kodama Keisuke
• Katoh Shunya

Classifications

• G02B5/3016 Primary

  involving passive liquid crystal elements (optical properties of liquid crystals G02F1/0063; polarising elements associated with active liquid crystal devices G02F1/133528) · CPC title

• C09K19/3861

  containing condensed ring systems · CPC title

• C09K2019/0448

  the end chain group being a polymerizable end group, e.g. -Sp-P or acrylate · CPC title

• G02B5/30

  Polarising elements (light-modulating devices with active elements G02F1/00) · CPC title

• G02B5/18

  Diffraction gratings {(holographic optical elements G02B5/32, G03H; integrally combined with optical fibres G02B6/02057; for coupling light guides G02B6/34; integrally combined with optical integrated light guides G02B6/12; grating systems G02B27/44)} · CPC title