Liquid crystal composition, optical film, circularly polarizing plate for organic EL display, and method for producing optically anisotropic layer

Patent metadata

Field	Value
Publication number	US-11834600-B2
Application number	US-202217670906-A
Country	US
Kind code	B2
Filing date	Feb 14, 2022
Priority date	Aug 16, 2019
Publication date	Dec 5, 2023
Grant date	Dec 5, 2023

Abstract

Provided is a liquid crystal composition capable of forming an optically anisotropic layer, and method thereof, in which a variation in a twisted angle of liquid crystal compound in an in-plane direction is suppressed an optical film, and a circularly polarizing plate for an organic EL display. The liquid crystal composition contains a liquid crystal, optically active compound A which is a photosensitive optically active compound whose helical twisting power changes upon irradiation with light and has a molar absorption coefficient of 5,000 M −1 ·cm −1 or more with respect to light having a wavelength of 365 nm, and an optically active compound B having a molar absorption coefficient with respect to light having a wavelength of 365 nm smaller than the molar absorption coefficient of the optically active compound A, in which a mass content ratio of the optically active compound A to the liquid crystal compound is less than 0.01.

First claim

What is claimed is:

1. A liquid crystal composition comprising:
a liquid crystal compound,
an optically active compound A which is a photosensitive optically active compound whose helical twisting power changes upon irradiation with light and has a molar absorption coefficient of 5,000 M −1 ·cm −1 or more with respect to light having a wavelength of 365 nm; and
an optically active compound B having a molar absorption coefficient with respect to light having a wavelength of 365 nm smaller than the molar absorption coefficient of the optically active compound A,
wherein a mass content ratio of the optically active compound A to the liquid crystal compound is less than 0.01.

2. The liquid crystal composition according to claim 1 ,
wherein the optically active compound A has a molar absorption coefficient of 15,000 M −1 ·cm −1 or more with respect to light having a wavelength of 365 nm.

3. The liquid crystal composition according to claim 2 ,
wherein the optically active compound B has a molar absorption coefficient of less than 1,000 M −1 ·cm −1 with respect to light having a wavelength of 365 nm.

4. The liquid crystal composition according to claim 2 ,
wherein the liquid crystal compound is a polymerizable liquid crystal compound.

5. The liquid crystal composition according to claim 2 ,
wherein a helical direction of a helix induced by the optically active compound A is opposite to a helical direction of a helix induced by the optically active compound B.

6. The liquid crystal composition according to claim 1 ,
wherein the optically active compound B has a molar absorption coefficient of less than 1,000 M −1 ·cm −1 with respect to light having a wavelength of 365 nm.

7. The liquid crystal composition according to claim 1 ,
wherein the liquid crystal compound is a polymerizable liquid crystal compound.

8. The liquid crystal composition according to claim 1 ,
wherein a helical direction of a helix induced by the optically active compound A is opposite to a helical direction of a helix induced by the optically active compound B.

9. The liquid crystal composition according to claim 1 ,
wherein an absolute value of a weighted average helical twisting power based on all the optically active compounds contained in the liquid crystal composition is 0.0 μm −1 or more and less than 0.5 μm −1 .

10. The liquid crystal composition according to claim 1 ,
wherein the helical twisting power of the optically active compound A changes by 20 μm −1 or more upon irradiation with light having a wavelength of 365 nm at an illuminance of 30 mW/cm 2 for 1 second.

11. The liquid crystal composition according to claim 1 ,
wherein the helical twisting power of the optically active compound B does not change by 5 μm −1 or more upon irradiation with light having a wavelength of 365 nm at an illuminance of 30 mW/cm 2 for 1 second.

12. The liquid crystal composition according to claim 1 ,
wherein the optically active compound A and the optically active compound B have a partial structure of any one of a binaphthyl partial structure, an isosorbide partial structure, or an isomannide partial structure.

13. The liquid crystal composition according to claim 1 ,
wherein the optically active compound A has a group containing a photoisomerizable double bond.

14. The liquid crystal composition according to claim 13 ,
wherein the group containing a photoisomerizable double bond is a cyanocinnamoyl group.

15. The liquid crystal composition according to claim 1 ,
wherein a mass content ratio of the optically active compound A to the liquid crystal compound is equal to or less than 0.006.

16. An optical film comprising:
a substrate; and
an optically anisotropic layer formed of the liquid crystal composition according to claim 1 arranged on the substrate.

17. The optical film according to claim 16 ,
wherein the optically anisotropic layer has, along a thickness direction, a first region in which an alignment state of the liquid crystal compound twist-aligned along a helical axis extending along a thickness direction is fixed, and a second region in which an alignment state of a homogeneously aligned liquid crystal compound is fixed.

18. A circularly polarizing plate for an organic EL display, comprising:
the optical film according to claim 16 ; and
a polarizer.

19. A method for producing an optically anisotropic layer, comprising:
a step 1 of forming a composition layer on a substrate using the liquid crystal composition according to claim 1 ;
a step 2 of subjecting the composition layer to a heat treatment to align the liquid crystal compound in the composition layer;
a step 3 of subjecting the composition layer to light irradiation under a condition of an oxygen concentration of 1% by volume or more, after the step 2; and
a step 4 of subjecting the light-irradiated composition layer to a curing treatment to fix an alignment state of the liquid crystal compound to form an optically anisotropic layer having a plurality of regions having different alignment states of the liquid crystal compound along a thickness direction,
wherein a step 5 of carrying out the step 3 under heating conditions, or subjecting the composition layer to a heat treatment between the step 3 and the step 4 is further provided.

20. The method for producing an optically anisotropic layer according to claim 19 ,
wherein the optically anisotropic layer has, along a thickness direction, a first region in which the alignment state of the liquid crystal compound twist-aligned along a helical axis extending along a thickness direction is fixed, and a second region in which the alignment state of a homogeneously aligned liquid crystal compound is fixed.

Assignees

• Fujifilm Corp

Inventors

• Kodama Keisuke
• Fukushima Yuki
• Katoh Shunya
• Takahashi Yuta
• Yoshida Shinpei
• YANOKUCHI Satoshi
• Maruyama Akira
• Hagio Hiroyuki

Classifications

• H10K59/8791

  Arrangements for improving contrast, e.g. preventing reflection of ambient light · CPC title

• C09K19/588 Primary

  Heterocyclic compounds · CPC title

• C09K19/586 Primary

  Optically active dopants; chiral dopants · CPC title

• C09K2019/546

  creating a polymeric network · CPC title

• C09K2019/0448

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