Liquid crystal display and manufacturing method thereof

Patent metadata

Field	Value
Publication number	US-10459291-B2
Application number	US-201715409621-A
Country	US
Kind code	B2
Filing date	Jan 19, 2017
Priority date	Jun 2, 2016
Publication date	Oct 29, 2019
Grant date	Oct 29, 2019

Abstract

A liquid crystal display includes: a first substrate, a second substrate overlapping the first substrate, a liquid crystal layer positioned between the first substrate and the second substrate and including a plurality of liquid crystal molecules, a first alignment layer positioned between the first substrate and the liquid crystal layer, a second alignment layer positioned between the second substrate and the liquid crystal layer, and a plurality of protrusions positioned at at least one of between the first alignment layer and the liquid crystal layer and between the second alignment layer and the liquid crystal layer, wherein at least one among the plurality of protrusions includes a polymer of a reactive mesogen, and the reactive mesogen is represented by Chemical Formula 1:

P a —A 1 —O CH 2 n O—A 2 —P b   Chemical Formula 1.

First claim

What is claimed is:

1. A liquid crystal display, comprising:
a first substrate;
a second substrate overlapping the first substrate;
a liquid crystal layer positioned between the first substrate and the second substrate and including a plurality of liquid crystal molecules;
a first alignment layer positioned between the first substrate and the liquid crystal layer;
a second alignment layer positioned between the second substrate and the liquid crystal layer; and
a plurality of protrusions positioned at at least one of the positions of between the first alignment layer and the liquid crystal layer, and between the second alignment layer and the liquid crystal layer,
wherein the first alignment layer includes a first polymer, the first polymer includes a first main chain and a plurality of first side chains connected to the first main chain, and at least one among the plurality of first side chains includes at least one of a photoreactive group and a photoreactive group derivative,
wherein at least one among the plurality of protrusions includes a polymer of a reactive mesogen,
wherein the photoreactive group or photoreactive group derivative is chemically combined with the polymer of the reactive mesogen included in the plurality of protrusions, and
the reactive mesogen is represented by Chemical Formula 1:
P a —A 1 —O CH 2 n O—A 2 —P b   Chemical Formula 1

wherein, in Chemical Formula 1,
Pa and Pb are independently an acrylate group or a methacrylate group,
A 1 includes

 in which at least one hydrogen connected to a carbon ring is unsubstituted or substituted with one selected from a group including F, CI, and Br,
A 2 includes any one of

 in which at least one hydrogen connected to the carbon ring is unsubstituted or substituted with one selected from the group including F, CI, and Br, and
n is a natural number of 2 to 5.

2. The liquid crystal display as claimed in claim 1 , wherein
the second alignment layer includes a second polymer, the second polymer includes a second main chain and a plurality of second side chains connected to the second main chain, and the plurality of second side chains do not include the photoreactive group and the photoreactive group derivative.

3. The liquid crystal display as claimed in claim 1 , wherein the reactive mesogen is represented by Chemical Formula A or Chemical Formula B:

wherein, in Chemical Formula A and Chemical Formula B, Pa and Pb are independently the acrylate group or the methacrylate group, S is one selected from a group including F, Cl, and Br, x is 0, 1, 2, or 3, and n is the natural number of 2 to 5.

4. The liquid crystal display as claimed in claim 1 , wherein the reactive mesogen has heat resistance of about 250 degrees Celsius or more.

5. The liquid crystal display as claimed in claim 4 , wherein
the density of the protrusions positioned between the first alignment layer and the liquid crystal layer is higher than the density of the protrusions positioned between the second alignment layer and the liquid crystal layer among the plurality of protrusions.

6. The liquid crystal display as claimed in claim 1 , wherein
the pre-tilt angle of the liquid crystal molecules adjacent to the first alignment layer among the plurality of liquid crystal molecules is larger than the pre-tilt angle of the liquid crystal molecules adjacent to the second alignment layer among the plurality of liquid crystal molecules.

7. The liquid crystal display as claimed in claim 1 , wherein the first substrate and the second substrate have a curved surface.

8. The liquid crystal display as claimed in claim 1 , further comprising:
a thin film transistor positioned between the first substrate and the first alignment layer;
a pixel electrode connected to the thin film transistor; and
a common electrode forming an electric field with the pixel electrode.

9. The liquid crystal display as claimed in claim 1 , wherein
the first alignment layer includes a lower alignment layer, an upper alignment layer, and a buffer region positioned between the lower alignment layer and the upper alignment layer,
the upper alignment layer includes at least one of the photoreactive group and the photoreactive group derivative, the lower alignment layer does not include the photoreactive group and the photoreactive group derivative, and the buffer region includes less of the photoreactive group than the content of at least one of the photoreactive group and the photoreactive group derivative of the upper alignment layer.

10. A method for manufacturing a liquid crystal display, comprising:
preparing a lower panel including a first alignment layer positioned on a first substrate;
preparing an upper panel including a second alignment layer positioned on a second substrate;
forming a liquid crystal layer positioned between the lower panel and the upper panel and including a plurality of liquid crystal molecules;
heat-treating the upper panel and the lower panel; and
irradiating light to the lower panel, the upper panel, and the liquid crystal layer in a state in which an electric field is applied to the liquid crystal layer, and
in the step of the heat treatment, the reactive mesogen included in at least one of the first alignment layer and the second alignment layer is adsorbed into the liquid crystal layer,
in the light irradiation step, the reactive mesogen is polymerized to form a plurality of protrusions positioned at at least one of the positions of between the first alignment layer and the liquid crystal layer, and between the second alignment layer and the liquid crystal layer,
wherein the first alignment layer includes a first polymer, the first polymer includes a first main chain and a plurality of first side chains connected to the first main chain, and at least one among the plurality of first side chains includes at least one of a photoreactive group and a photoreactive group derivative,
wherein the photoreactive group or photoreactive group derivative is chemically combined with the polymer of the reactive mesogen forming the plurality of protrusions, and
the reactive mesogen is represented by Chemical Formula 1:
P a —A i —O CH 2 n O—A 2 —P b   Chemical Formula 1

wherein, in Chemical Formula 1, Pa and Pb are independently an acrylate group or a methacrylate group,
A 1 includes

 in which at least one hydrogen connected to a carbon ring is unsubstituted or substituted with one selected from a group including F, CI, and Br,
A 2 includes any one of

 in which at least one hydrogen connected to the carbon ring is unsubstituted or substituted with one selected from the group including F, CI, and Br, and n is a natural number of 2 to 5.

11. The method as claimed in claim 10 , wherein the second alignment layer includes a second polymer, the second polymer includes a second main chain and a plurality of second side chains connected to the second main chain, and the plurality of second side chains do not include the photoreactive group.

12. The method as claimed in claim 10 , wherein the reactive mesogen is represented by Chemi

Assignees

• Samsung Display Co Ltd

Inventors

• Lee Hyeok Jin
• Kwon Oh Jeong
• Kim Ka Eun
• Kim Soo Dong
• Kim Su Jin
• Kim Jin Won
• Cho Jae Bum
• Jeon Baek Kyun

Classifications

• C08F22/1006

  of polyhydric alcohols or polyhydric phenols, e.g. ethylene glycol dimethacrylate · CPC title

• G02F1/134309

  characterised by their geometrical arrangement · CPC title

• C09K19/3852

  Poly(meth)acrylate derivatives · CPC title

• G02F1/133711 Primary

  by organic films, e.g. polymeric films · CPC title

• G02F1/133788

  by light irradiation, e.g. linearly polarised light photo-polymerisation · CPC title