WO2013189147A1

WO2013189147A1 - Reflective polarizer, method for producing same and liquid crystal display device

Info

Publication number: WO2013189147A1
Application number: PCT/CN2012/084838
Authority: WO
Inventors: 崔晓鹏; 林鸿涛; 封宾; 马国靖; 赵成明
Original assignee: 京东方科技集团股份有限公司; 北京京东方显示技术有限公司
Priority date: 2012-06-20
Filing date: 2012-11-19
Publication date: 2013-12-27
Also published as: CN102749669A

Abstract

A reflecting polarizer, method for producing the same and a liquid crystal display device. The reflecting polarizer has both optical compensation performance and broadband reflection performance can be produced. Wherein, the reflecting polarizer comprises a first substrate, a first alignment layer which is arranged on the first substrate, a chiral coating which is formed on the first alignment layer, a second substrate which is arranged with the first substrate in a box manner and is provided with a second alignment layer, and cholesteric liquid crystals which are filled in a clearance, wherein the chiral coating is formed by coating chiral discotic liquid crystal solution onto the first alignment layer; spacers are arranged between the chiral coating and the second alignment layer for forming the clearance.

Description

Reflective polarizing plate, method for preparing reflective polarizing plate, and liquid crystal display device

The present disclosure relates to the field of liquid crystal display technology, and more particularly to a reflective polarizer, a method of preparing a reflective polarizer, and a liquid crystal display device. Background technique

With the rapid development of liquid crystal display technology, polarizing plates used in liquid crystal displays are also becoming more and more important. A polarizing plate is an optical component that can convert natural light into polarized light and is an important component of liquid crystal displays.

Due to the selective reflection properties of biliary liquid crystals with a special helical structure, this special optical property makes biliary liquid crystals widely used in liquid crystal displays, storage materials, infrared radiation shielding materials and "smart" windows. A reflective polarizing plate made of a cholesteric liquid crystal enables the polarizing plate to have a function of selective reflection.

Since the reflection type polarizing plate made of the cholesteric liquid crystal alone has a narrow reflection wave width, the reflection wave width of the reflection type polarizing plate is conventionally increased by adding a chiral compound to the cholesteric liquid crystal. However, since the chiral compound and the bile phase liquid crystal molecules have similar chemical structures and good molecular compatibility, the diffusion control is difficult, so the fabrication process is difficult to control, thus causing the reflection wavelength of the reflective polarizer. Still narrow. Summary of the invention

Embodiments of the present disclosure provide a reflective polarizing plate, a method of preparing a reflective polarizing plate, and a liquid crystal display device capable of performing optical compensation by heat treatment and light irradiation treatment of chiral discotic liquid crystal and bile phase liquid crystal. Reflective polarizer for performance and broadband reflection performance.

According to an aspect, an embodiment of the present disclosure provides a reflective polarizer comprising: a first substrate; a first alignment film disposed on the first substrate; a chiral coating formed on the first alignment film, The chiral coating is prepared by coating a chiral discotic liquid crystal solution on a first alignment film, wherein the chiral discotic liquid crystal solution is at least composed of a photopolymerizable chiral disc liquid crystal monomer. And a photoinitiator and a thermal polymerization inhibitor are dissolved in the organic solvent; and the second substrate having the second alignment film disposed on the first substrate is disposed between the chiral coating and the second alignment film a spacer to form a gap; a bile-phase liquid crystal filled in the gap, wherein the bile phase liquid crystal is at least composed of nematic liquid crystal, photopolymerizable The nematic liquid crystal monomer, the chiral compound, the photoinitiator, and the thermal polymerization inhibitor are mixed.

According to another aspect, an embodiment of the present disclosure provides a method of preparing a reflective polarizer, comprising: disposing a first alignment film on a first substrate; and applying a chiral disc liquid crystal solution to the first alignment film Forming a chiral coating, wherein the chiral discotic liquid crystal solution is obtained by dissolving at least a photopolymerizable chiral discotic liquid crystal monomer, a photoinitiator and a thermal polymerization inhibitor in an organic solvent; Forming a thin film device between the substrate and the second substrate provided with the second alignment film, and providing a spacer between the chiral coating and the second alignment film of the second substrate to form a gap; Liquid crystal is injected into the gap, wherein the cholesteric liquid crystal is obtained by mixing at least a nematic liquid crystal, a photopolymerizable nematic liquid crystal monomer, a chiral compound, a photoinitiator, and a thermal polymerization inhibitor; And light irradiation treatment to form a reflective polarizer.

According to another aspect, an embodiment of the present disclosure provides a liquid crystal display device including an array substrate, a color filter substrate disposed parallel to the array substrate and disposed on the array substrate, and disposed between the array substrate and the color filter substrate. The liquid crystal layer further includes: a reflective polarizing plate having any of the above features disposed on the array substrate opposite to the liquid crystal layer and disposed on the color film substrate opposite to the liquid crystal layer.

The reflective polarizer provided by the embodiment of the present disclosure, the method for preparing the reflective polarizer, and the liquid crystal display device are prepared by applying a chiral discotic liquid crystal solution on the first alignment film to prepare a chiral coating. After the bile phase liquid crystal is injected into the gap of the thin film device, the thin film device provided with the chiral coating and the gallium-phase liquid crystal is subjected to heat treatment and photo-irradiation treatment to form a reflective polarizing film. Through this scheme, the chiral discotic molecules in the chiral coating slowly diffuse in the cholesteric liquid crystal by heat treatment and photoirradiation treatment, and form a chiral discotic liquid crystal polymer network and nematic liquid crystal. The monomer polymer network further increases the reflection wavelength of the cholesteric liquid crystal, thereby enabling the preparation of a reflective polarizer having both optical compensation performance and wide-band reflection performance, and increasing the reflection polarization in the prior art. The reflected wave width of the sheet. DRAWINGS

In order to more clearly illustrate the technical solutions of the present disclosure or the prior art, the following description of the technical solutions provided in the present disclosure or the drawings used in the prior art description will be briefly introduced. Obviously, the drawings in the following description Only some of the specific embodiments of the technical solutions of the present disclosure are illustrated, and those skilled in the art can obtain other drawings according to the drawings without any creative work. In order to more clearly illustrate the embodiments of the present disclosure or the technical solutions in the prior art, the drawings to be used in the embodiments or the description of the prior art will be briefly described below. Obviously, the drawings in the following description are only It is a certain embodiment of the present disclosure, and other drawings can be obtained from those skilled in the art without any creative work.

1 is a schematic structural view of a reflective polarizer according to an embodiment of the present disclosure;

2 is a schematic flow chart of a method for preparing a reflective polarizing plate according to an embodiment of the present disclosure;

3 is a schematic structural view showing a state in a process of preparing a reflective polarizing plate according to an embodiment of the present disclosure;

4 is a schematic structural view of a second state in a process of preparing a reflective polarizer according to an embodiment of the present disclosure;

5 is a schematic structural view of a photopolymerizable chiral discotic liquid crystal cell according to an embodiment of the present disclosure;

6 is a schematic structural view showing a third state in a preparation process of a reflective polarizing plate according to an embodiment of the present disclosure;

7 is a schematic structural view showing a fourth state in the process of preparing a reflective polarizing plate according to an embodiment of the present disclosure;

8 is a schematic view showing the molecular structure of a photopolymerizable nematic liquid crystal monomer according to an embodiment of the present disclosure;

9 is a schematic view showing the molecular structure of a chiral compound R811 according to an embodiment of the present disclosure; FIG. 10 is a schematic view showing the molecular structure of a photoinitiator 1651 according to an embodiment of the present disclosure; and FIG. 11 is a reflection spectrum of a reflective polarizing plate according to an embodiment of the present disclosure. Figure

12 is a graph showing a phase retardation curve of a chiral liquid crystal molecule according to an embodiment of the present disclosure. detailed description

The technical solutions in the embodiments of the present disclosure will be clearly and completely described in conjunction with the drawings in the embodiments of the present disclosure. It is obvious that the described embodiments are only a part of the embodiments of the present disclosure, and not all of the embodiments. All other embodiments obtained by a person of ordinary skill in the art based on the embodiments of the present disclosure without departing from the inventive scope are the scope of the disclosure. The embodiment of the present disclosure provides a reflective polarizing plate 1, as shown in FIG. 1, comprising: a first substrate 10; a first alignment film 11 disposed on the first substrate 10; and a hand formed on the first alignment film 11. The characterization coating 12, wherein the chiral coating 12 is prepared by coating a chiral discotic liquid crystal solution on the first alignment film 11, wherein the chiral discotic liquid crystal solution is at least soluble in organic a photopolymerizable chiral discotic liquid crystal monomer of a solvent, a photoinitiator and a thermal polymerization inhibitor; a second substrate 16 having a second alignment film 15 disposed on the first substrate 10, wherein the chiral coating A spacer 13 is disposed between the layer 12 and the second alignment film 15 to form a gap; a cholesteric liquid crystal 14 filled in the gap, wherein the cholesteric liquid crystal 14 is volatilized by a bile phase liquid crystal solution, The bile phase liquid crystal solution includes at least an organic solvent, a nematic liquid crystal, a photopolymerizable nematic liquid crystal monomer, a chiral compound, a photoinitiator, and a thermal polymerization inhibitor.

In one example, the chiral discotic liquid crystal solution comprises at least a photopolymerizable chiral discotic liquid crystal monomer to which an organic solvent is added, a photoinitiator in a weight percentage of 0.1 to 10 weight percent, and a weight percentage of 0.01. To a thermal polymerization inhibitor of weight percentage 10.

Wherein, the weight percentage of a substance means: a substance occupies the weight ratio of the whole solution, that is, the weight of the whole solution is B, and the weight of a substance contained in the solution is A, then the weight percentage of the substance is 100*A /B. For example, a photoinitiator having a weight percentage of 0.1 to 10 weight percent means that the weight percentage of the photoinitiator to the chiral discotic liquid crystal solution is between 0.1 and 10, that is, the photoinitiator is in the chiral discotic liquid crystal. The ratio in the solution is between 0.1% and 10% and contains the boundary value (0.1%, 10%).

In one example, the weight ratio of the photopolymerizable chiral discotic liquid crystal monomer to the organic solvent is 1:19.

Illustratively, the photopolymerizable chiral discotic liquid crystal monomer molecule is a symmetric type formed by a photopolymerization branch and a chiral branch by an acid bond, an ester bond, an amide bond or a carbonate bond. An asymmetric discotic liquid crystal molecule; the disc core is selected from the group consisting of pyrogallol, pyridazine, anthracene, benzophenanthrene, trimeric fluorene, hexaacetylene benzene, and hexabenzopyrene; photopolymerizable branch The terminal group is selected from the group consisting of acrylates, mercapto acrylates, styrenes, diacetyls, or a mixture of two or more, and the chiral branched end groups are selected from the group consisting of octanol and isova. Any one or a mixture of two or more of alcohol, cholesterol, and menthol. The number of photopolymerizable branches may be 1-5; the number of chiral branches may be 1-5.

The mixing of two or more means that the photopolymerizable branches and the chiral branches in a photopolymerizable chiral discotic liquid crystal monomer molecule may be different, and further, each photopolymerizable branch End The base and chiral branched end groups may also be different. Specifically, for example, if the photopolymerizable chiral discotic liquid crystal monomer molecule comprises three photopolymerizable branched end groups, the first photopolymerizable branched end group may be an acrylate type, and the second The photopolymerized branched end group may be the same as or different from the first photopolymerizable branched end group, and the third photopolymerizable branched end group may be identical to the first photopolymerizable branched end group and/or The two photopolymerizable branched end groups are the same or different.

In one example, the cholesteric liquid crystal solution comprises: an organic solvent, a nematic liquid crystal dissolved in the organic solvent, and a photopolymerizable amount of 0.1 to 30% by weight in the organic solvent. a nematic liquid crystal monomer, a chiral compound dissolved in the organic solvent in an amount of from 1 to 60% by weight, a photoinitiator dissolved in the organic solvent in an amount of from 0.1 to 10% by weight, and dissolved The thermal solvent is from 0.01 to 10% by weight of the organic solvent.

In one example, the cholesteric liquid crystal solution comprises: an organic solvent, a nematic liquid crystal having a weight percentage of 64.8 dissolved in the organic solvent, and a photopolymerizable weight of 15.0 dissolved in the organic solvent. a nematic liquid crystal monomer, a chiral compound having a weight percentage of 14.8 dissolved in the organic solvent, a photoinitiator having a weight percentage of 4.4 dissolved in the organic solvent, and a weight percentage dissolved in the organic solvent of 1.0 Thermal polymerization inhibitor.

Similarly, the weight percentage of a substance herein means: the weight ratio of a substance to the whole solution, that is, the weight of the whole solution is B, and the weight of a substance contained in the solution is A, then the weight percentage of the substance is 100*A/B. For example, a nematic liquid crystal having a weight percentage of 64.8 means that the weight percentage of the nematic liquid crystal and the cholesteric liquid crystal solution is 64.8, that is, the ratio of the nematic liquid crystal in the cholesteric liquid crystal solution is 64.8.

In one example, the photopolymerizable nematic liquid crystal monomer is selected from any one or a mixture of two or more of an acrylate, a mercapto acrylate, a styrene group, and a diacetyl group.

In one example, the chiral compound is selected from the group consisting of R811 (benzoic acid, 4-hexyloxy, 4-[[[(1R)-1-indolylheptyl]oxy]carbonyl]phenyl), S811 ( Benzoic acid, 4-hexyloxy, 4-[[[( IS ) -1-decylheptyl]oxy]carbonyl]phenyl ester;), CB15( ( + )-4, -( 2 fluorenyl) Butyl)-4-biphenyl cyanide, ZLI4572 (benzoic acid, 4-(p--4-pentylcyclohexyl), (1R)-1-phenyl-1,2-ethanedi-decyl) Any one or a mixture of two or more.

In one example, the photoinitiator is selected from the group consisting of dibenzoyl peroxide, dodecyl peroxide, azobisisobutyronitrile, diisopropyl peroxydicarbonate, dicyclohexyl peroxydicarbonate. One; the thermal polymerization inhibitor is hydroquinone, p-benzoquinone, 2-tert-butyl hydroquinone, 2, 5-di-tert-butyl hydroquinone Any of them.

In one example, the organic solvent is selected from the group consisting of ethanol, acetone, dichlorodecane, trichlorodecane, carbon tetrachloride, tetrahydrofuran, isopropanol, cyclohexane, benzene, toluene, and diphenylbenzene. Kind.

In one example, the spacer 13 is a glass microsphere having a diameter of from 10 micrometers to 300 micrometers. It should be noted that the embodiment of the present disclosure does not limit the arrangement of the spacers, and may be uniformly distributed between the chiral coating and the second alignment film of the second substrate, or may be only in chirality. The coating is disposed along the edge of the polarizing plate with the second alignment film of the second substrate.

In one example, the material of the first alignment film 11 or the second alignment film 15 is polyimide. As shown in FIG. 1, after the cholesteric liquid crystal 14 is filled in the gap, the chiral discotic molecules in the chiral coating 12 are directed to the cholesteric liquid crystal 14 due to heat treatment and light irradiation treatment. The diffuse diffusion slowly forms a nematic liquid crystal monomer polymer network 17 and a chiral discotic liquid crystal polymer network 18, thereby increasing the reflected wave width of the cholesteric liquid crystal 14. And, since the chiral discotic liquid crystal has a light-compensating reflective polarizing plate provided by the embodiment of the present disclosure, a chiral coating is formed on the first substrate provided with the first alignment film, and is parallel to the first substrate And a bile phase liquid crystal is disposed between the second substrate having the second alignment film and the chiral coating disposed on the chiral coating pair. According to this scheme, since the heat treatment and the photoirradiation treatment are performed after the bile phase liquid crystal is injected into the gap, the chiral discotic molecules slowly diffuse toward the cholesteric liquid crystal, and form a chiral discotic liquid crystal polymer. The network and the nematic liquid crystal monomer polymer network further increase the reflection wavelength of the cholesteric liquid crystal. In one example, the reflective polarizer has both optical compensation performance and wide-band reflection performance.

A method for preparing a reflective polarizer provided by an embodiment of the present disclosure, as shown in FIG. 2, includes the following steps:

5101. A first alignment film is disposed on the first substrate.

Illustratively, as shown in FIG. 3, a first alignment film 11 is disposed on the first substrate 10. The material of the first alignment film 11 used in the embodiment of the present disclosure is polyimide, which enables coating on the poly The liquid crystal molecules of the imide oriented film are oriented parallel to the array substrate.

5102. Applying a chiral discotic liquid crystal solution to the first alignment film 11 to prepare a chiral coating 12. As shown in Fig. 4, a chiral coating 12 is formed on the first alignment film 11. Wherein the chiral discotic liquid crystal solution is obtained by dissolving at least an organic solvent in a photopolymerizable chiral discotic liquid crystal monomer, a photoinitiator and a thermal inhibitor.

After the first alignment film is disposed on the first substrate, the chiral discotic liquid crystal solution is applied to the first On the alignment film 11, wherein the chiral discotic liquid crystal solution is obtained by dissolving at least an organic solvent in a photopolymerizable chiral discotic liquid crystal monomer, a photoinitiator, and a thermal polymerization inhibitor.

Illustratively, a method of preparing a chiral discotic liquid crystal solution includes:

The photopolymerizable chiral discotic liquid crystal monomer is dissolved in an organic solvent, and the photopolymerizable chiral disc-shaped liquid crystal monomer is a substance having a discotic liquid crystal intermediate phase;

a photoinitiator having a weight percentage of 0.1 to 10% by weight and a thermal polymerization inhibitor having a weight percentage of 0.01 to 10% by weight are added to the organic solvent;

The organic solvent of the photopolymerizable chiral discotic liquid crystal monomer, photoinitiator and thermal polymerization inhibitor is stirred and mixed for 1 minute to 60 minutes to prepare a chiral discotic liquid crystal solution.

Specifically, the method of preparing the chiral discotic liquid crystal solution may be:

The photopolymerizable chiral discotic liquid crystal monomer is dissolved in a tetrahydrofuran solvent in a ratio of 1:19; a photoinitiator having a weight percentage of 0.1 to 10% by weight and a thermal resistance of 0.01 to 10% by weight Adding a monomer to the tetrahydrofuran solvent;

The tetrahydrofuran solvent was stirred for 30 minutes under a sealed condition to prepare a chiral discotic liquid crystal solution of 5 parts by weight.

It should be added that the molecular structure of the photopolymerizable chiral discotic liquid crystal monomer is a symmetric or non-formation formed by an acid bond, an ester bond, an amide bond or a carbonate bond, and a photopolymerizable branch and a chiral branch. Symmetrical discotic liquid crystal molecules;

The disc core of the photopolymerizable chiral discotic liquid crystal monomer molecule is selected from any one of pyrogallol, pyridazine, anthracene, triphenylene, trimeric anthracene, hexaacetylenebenzene, and hexabenzopyrene or a mixture of two or more kinds; the photopolymerizable branched end group is selected from the group consisting of acrylates, mercapto acrylates, styrenes, diacetyls, or a mixture of two or more, photopolymerizable The number of chains is 1-5; the chiral branched end groups are selected from any one or a mixture of two or more of octanol, isoamyl alcohol, cholesterol, menthol, and the number of chiral branches is one. -5.

In general, a TFT-LCD (Thin Film Transistor-Liquid Crystal Display) uses an optical positive liquid crystal, and when viewed at a large angle, a positive phase retardation occurs, resulting in a decrease in contrast and a decrease in viewing angle. The discotic liquid crystal has an optical negative characteristic opposite to that of the optical positive liquid crystal, and has a negative phase retardation. This negative phase retardation can be used to compensate the positive phase retardation of the TFT-LCD, and thus the optically negative disc shape. The liquid crystal material can be used to fabricate an optical compensation film of a TFT-LCD. The chiral discotic liquid crystal of the present disclosure has optical compensation characteristics Learn the compensation characteristics.

Wherein, by way of example, FIG. 5 shows the structure of a photopolymerizable chiral discotic liquid crystal monomer molecule which is a symmetric discotic liquid crystal molecule having a molecular formula of tri-1 , 3 , 5-acryloyloxy Hexyloxybenzoic acid-tris-2,4,6-sec-octyloxybenzoic acid-benzophenanthrene ester. Among them, the disk core is a commonly used benzophenanthrene; the three polymerizable branches are acryloyloxyhexyloxybenzoic acid, wherein the polymerizable branched end group is acrylic acid, and the three chiral branches are secondary octane oxygen. Benzophthalic acid, wherein the chiral branched end group is octanol.

5103. Forming a thin film device on the first substrate 10 and the second substrate 16 provided with the second alignment film 15, and providing a spacer between the chiral coating 12 and the second alignment film 15 of the second substrate 16. Object 13 to form a gap.

After the completion of the chiral coating 12 on the first alignment film 11, the first substrate 10 and the second substrate 16 provided with the second alignment film 15 are paired to form a thin film device, and in the chiral coating 12 and A spacer 13 is disposed between the second alignment films 15 of the second substrate 16 to form a gap.

As shown in FIG. 6, the first substrate 10 is placed in a box with the second substrate 16 having the second alignment film 15 disposed parallel to the first substrate 10 and disposed with the chiral coating 12, and in the chiral A spacer 13 is provided between the sexual coating 12 and the second alignment film 15 to form a gap.

It is to be noted that the spacer 13 may be a glass bead having a diameter of 10 μm to 300 μm, and the material of the second alignment film 15 may also be a polyimide.

5104, injecting a cholesteric liquid crystal 14 into the gap, wherein the cholesteric liquid crystal 14 is composed of at least a nematic liquid crystal, a photopolymerizable nematic liquid crystal monomer, a chiral compound, a photoinitiator, and a thermal polymerization inhibitor. Mixed income.

A spacer is disposed between the chiral coating 12 on the first substrate 10 in the thin film device and the second alignment film 15 on the second substrate 16 to form a gap, and then the cholesteric liquid crystal is injected into the gap formed. Illustratively, the cholesteric liquid crystal is injected into the gap under vacuum, wherein the cholesteric liquid crystal exhibits orientation parallel to the array substrate due to the action of the second alignment film.

As shown in Fig. 7, the cholesteric liquid crystal 14 is filled in the gap.

First, a brief introduction to cholesteric liquid crystals is required:

The cholesteric liquid crystal has a selective spiral structure because of its special helical structure. There are generally two sources of cholesteric liquid crystals: one is a liquid crystal molecule itself having a chiral group; the other is obtained by incorporating a chiral compound into a nematic liquid crystal.

In the bile phase liquid crystal, the long axis of the liquid crystal molecules periodically rotates around a spiral axis to form a spiral structure. The distance traveled by the long axis of liquid crystal molecules 360 is called the pitch P, the size and liquid of P The content of chiral compounds in the crystal is inversely proportional. The reflection wavelength of the single-pitch cholesteric liquid crystal = ΔηΡ, where Δη is the birefringence of the liquid crystal material, respectively.

In the range of the reflected wave width, the left (right) rotated circularly polarized light is reflected by the left (right) rotating cholesteric liquid crystal, while the right (left) rotated circularly polarized light is transmitted; Outside the wide range, both left and right circularly polarized light are transmitted. For this reason, the bile phase liquid crystal can also be used as a reflective polarizer. The visible light is reflected by the visible light to obtain circularly polarized light, which is then converted into linearly polarized light by a quarter wave plate, and can be directly used for a liquid crystal display.

The cholesteric liquid crystal of the embodiment of the present disclosure is obtained by mixing at least a nematic liquid crystal, a photopolymerizable nematic liquid crystal monomer, a chiral compound, a photoinitiator, and a thermal polymerization inhibitor.

Illustratively, a method of preparing a cholesteric liquid crystal includes:

The nematic liquid crystal, the photopolymerizable nematic liquid crystal monomer having a weight percentage of 0.1 to 30% by weight, a chiral compound having a weight percentage of 1 to 60% by weight, and a weight percentage of 0.1 to 10% by weight a photoinitiator, a thermal polymerization inhibitor having a weight percentage of 0.01 to 10% by weight, dissolved in an organic solvent;

The organic solvent is volatilized to prepare a cholesteric liquid crystal having a single pitch with a liquid crystal phase temperature in the range of 60 °C to 120 °C.

Specifically, the method for preparing the cholesteric liquid crystal may be:

a nematic liquid crystal having a weight percentage of 64.8, a photopolymerizable nematic liquid crystal monomer having a weight percentage of 15.0, a chiral compound having a weight percentage of 14.8, a photoinitiator having a weight percentage of 4.4, and a heat of 1.0 by weight. The polymerization inhibitor is dissolved in an organic solvent;

After dissolving the mixture in a solvent, the solvent is volatilized to prepare a bile phase liquid crystal having a single pitch in a liquid crystal phase temperature in the range of 60 °C to 120 °C.

It is to be noted that the photopolymerizable nematic liquid crystal monomer is any one or a mixture of two or more of an acrylate, a mercapto acrylate, a styrene group, and a diacetyl group;

The chiral compound is selected from any one or more of R811, S811, CB15, ZLI4572;

The photoinitiator is selected from the group consisting of dibenzoyl peroxide, dodecyl peroxide, azobisisobutyronitrile, diisopropyl peroxydicarbonate, and dicyclohexyl peroxydicarbonate;

The thermal polymerization inhibitor is selected from the group consisting of hydroquinone, p-benzoquinone, 2-tert-butyl hydroquinone, and 2, 5-di-tert-butyl hydroquinone;

The solvent is selected from the group consisting of ethanol, acetone, dichlorodecane, trichlorodecane, carbon tetrachloride, tetrahydrofuran, and different Any one of propanol, cyclohexane, benzene, toluene, and diphenyl.

Figure 8 shows the structure of a photopolymerizable nematic liquid crystal monomer C6M which is an acrylate photopolymerizable nematic liquid crystal having a molecular formula of 1, 4-bis(4-(6, -propyleneoxy) Oxyphenyl)benzoyloxy)-2-indenylbenzene, both photoactive functional groups are acrylates;

Figure 9 shows the molecular structure of the chiral compound R811, which has the formula: (benzoic acid, 4-hexyloxy, 4-[[[(l))-l-decylheptyl]oxy]carbonyl]phenyl));

Figure 10 shows the molecular structure of photoinitiator 1651 having the formula 2,2-dimethoxyoxy-phenylfluorenone.

It should be noted that, in the embodiments of the present disclosure, several components constituting the bile phase liquid crystal are: nematic liquid crystal, chiral compound, photopolymerizable nematic liquid crystal monomer, photoinitiator, and may also be selected according to The composition, the process and the actual needs determine whether or not to add other components such as achiral small molecule liquid crystal, smectic liquid crystal, dye, etc., and the disclosure is not limited.

S105. The thin film device is subjected to heat treatment and light irradiation treatment to form a reflective polarizing plate. After the cholesteric liquid crystal is injected into the gap of the thin film device, the thin film device is subjected to heat treatment and photoirradiation treatment to form a reflective polarizing plate.

As shown in FIG. 1, after the cholesteric liquid crystal 14 is injected into the gap of the thin film device, the thin film device is subjected to heat treatment and light irradiation treatment, and the chiral discotic molecules slowly diffuse toward the bile phase liquid crystal 14 and form a chiral sign. The discotic liquid crystal polymer network 17 and the nematic liquid crystal monomer polymer network 18 further increase the reflected wave width of the cholesteric liquid crystal 14.

Illustratively, the process of heat-treating and photo-irradiating the thin film device to form the reflective polarizer may include:

The film device is heated to a temperature ranging from 90 ° C to 120 ° C, preheated for 1 minute to 60 minutes, and subjected to ultraviolet irradiation polymerization crosslinking, wherein the ultraviolet irradiation time is 1 minute to 60 minutes, and the ultraviolet wavelength is 365 nm. The irradiation dose was 0.001 mW per square centimeter to 100 mW per square centimeter to prepare a reflective polarizing plate.

Specifically, the method of performing heat treatment and light irradiation treatment on the thin film device to form the reflective polarizing plate may be:

The thin film device was heated to 110 ° C, preheated for 30 minutes, and subjected to ultraviolet irradiation polymerization cross-linking, wherein the ultraviolet irradiation time was 30 minutes, the ultraviolet wavelength was 365 nm, and the irradiation dose was 10 mW per square centimeter. During heat treatment and ultraviolet irradiation, chiral discotic molecules diffuse into the cholesteric liquid crystal and form a nematic liquid crystal monomer polymer network and a chiral discotic liquid crystal polymer network. This increases the reflection wavelength of the bile phase liquid crystal, thereby producing a reflective polarizer having both optical compensation performance and wide-band reflection performance.

Curve 1 of Fig. 11 shows a curve in which the reflectance of the prepared reflective polarizing plate which was prepared by preheating at 110 ° C for 30 minutes at a temperature of 25 ° C as a function of incident wavelength, and in Fig. 11, the horizontal axis was a reflection type. The reflection beam width of the polarizing plate, and the vertical axis is the reflectance of the reflective polarizing plate. As shown by the curve 1 in Fig. 11, the reflected circularly polarized light has a wavelength in the range of 400 to 700 nm and a reflection bandwidth of 300 nm. The curve of the reflectance of the next test as a function of the incident wavelength. As shown in Fig. 11, as the preheating time is extended, the reflection center is displaced, and the reflection wave width is gradually narrowed. The wavelength of the reflected circularly polarized light is 420-680 nm, and the reflection bandwidth is 260 nm, which indicates that the preheating is performed. In the process, the preheating time is different, which causes the chiral discoid molecules to diffuse slowly in the bile phase liquid crystal, which causes the reflection wave width of the reflective polarizer to change.

In one example, after the prepared reflective polarizer is soaked with a solvent, a chiral coating is separated to test the phase retardation value of the chiral liquid crystal molecules in the chiral coating. Fig. 12 shows the phase retardation values of the chiral liquid crystal molecules of the chiral coating, wherein the horizontal axis represents the polarization angle and the vertical axis represents the phase retardation value. As shown in FIG. 12, when the polarization angle is a negative value, the chiral liquid crystal molecules can still generate a phase retardation, that is, the chiral liquid crystal molecules are optically negative discotic liquid crystals having optical compensation characteristics, thereby demonstrating the preparation of the present disclosure. The reflective polarizer has optical compensation characteristics.

A method for preparing a reflective polarizing plate provided by an embodiment of the present disclosure, by disposing a first alignment film on a first substrate, and dissolving a photopolymerizable chiral discotic liquid crystal monomer, a photoinitiator, and a thermal polymerization inhibitor The chiral discotic liquid crystal solution obtained by the organic solvent is coated on the first alignment film to prepare a chiral coating layer, and the first substrate and the second substrate provided with the second alignment film are paired to form a thin film device. And providing a spacer between the chiral coating and the second alignment film of the second substrate to form a gap, which is further caused by a nematic liquid crystal, a photopolymerizable nematic liquid crystal monomer, a chiral compound, and light. The cholesteric liquid crystal obtained by mixing the agent and the thermal polymerization inhibitor is injected into the gap of the thin film device, and the thin film device is subjected to heat treatment and light irradiation treatment to form a reflective polarizing plate. According to this scheme, a reflective polarizer having both optical compensation performance and wide-band reflection performance can be prepared, which increases the reflection wavelength of the reflective polarizer in the prior art.

A liquid crystal display device according to an embodiment of the present disclosure includes an array substrate, a color filter substrate disposed parallel to the array substrate and disposed on the array substrate, and a liquid crystal layer disposed between the array substrate and the color filter substrate. A reflective polarizing plate which is the same as the above embodiment and which is disposed on the opposite side of the liquid crystal layer on the array substrate and which is disposed on the color film substrate opposite to the liquid crystal layer.

The liquid crystal display device provided by the embodiment of the present disclosure may be a product or a component having a display function, such as a liquid crystal display, a liquid crystal television, a digital photo frame, a mobile phone, a tablet computer, etc.; and the liquid crystal display device may apply the above reflective polarization The structure of the reflective polarizer is the same as that of the above embodiment, and will not be described herein.

The above embodiments are merely illustrative of the present invention and are not to be construed as limiting the scope of the invention, and various modifications and changes can be made without departing from the spirit and scope of the invention. Equivalent technical solutions are also within the scope of the invention, and the scope of the invention is defined by the claims.

Claims

claims

1. A reflective polarizing plate, characterized by including:

first substrate;

a first alignment film disposed on the first substrate;

A chiral coating formed on the first alignment film, the chiral coating is prepared by coating a chiral discoidal liquid crystal solution on the first alignment film, wherein, the chiral discoidal The liquid crystal solution at least includes a photopolymerizable chiral discotic liquid crystal monomer dissolved in an organic solvent, a photoinitiator and a thermal polymerization inhibitor; a second substrate with a second alignment film that is arranged opposite the first substrate, A spacer is provided between the chiral coating and the second alignment film to form a gap;

The cholesteric liquid crystal filled in the gap, wherein the cholesteric liquid crystal is prepared by volatilization of a cholesteric liquid crystal solution, the cholesteric liquid crystal solution at least includes an organic solvent, a nematic liquid crystal, and a photopolymerizable nematic phase Liquid crystal monomers, chiral compounds, photoinitiators and thermal polymerization inhibitors.

2. The reflective polarizing plate according to claim 1, characterized in that,

The chiral discotic liquid crystal solution includes: an organic solvent, a photopolymerizable chiral discotic liquid crystal monomer dissolved in the organic solvent, and a weight percentage of 0.1 to 10 weight percent dissolved in the organic solvent. The photoinitiator and the thermal polymerization inhibitor dissolved in the organic solvent range from 0.01 to 10 weight percent.

3. The reflective polarizer according to claim 2, wherein the weight ratio of the photopolymerizable chiral discoidal liquid crystal monomer to the organic solvent is 1:19.

4. The reflective polarizer according to any one of claims 1 to 3, characterized in that the photopolymerizable chiral discoidal liquid crystal monomer molecule is a disc core formed through an acid bond, an ester bond, or an amide bond. Or a symmetrical or asymmetric discoidal liquid crystal molecule formed by photopolymerizable branches and chiral branches bonded by carbonate bonds; the disc core is selected from phloroglucinol, azine, perylene, benzophenanthrene, trimer Any one of indene, hexaethynylbenzene, and hexabenzocorone; the photopolymerizable branched chain end group is selected from any one of acrylates, methacrylates, styryl groups, and diacetyl groups. Or a mixture of two or more; the chiral branched end group is selected from any one or a mixture of two or more of secondary octanol, isoamyl alcohol, cholesterol, and menthol.

5. The reflective polarizing plate according to claim 4, characterized in that the number of the photopolymerizable branches is 1-5, and the number of the chiral branches is 1-5.

6. The reflective polarizer according to claim 1, wherein the cholesteric liquid crystal solution includes: an organic solvent, a nematic liquid crystal dissolved in the organic solvent, and a nematic liquid crystal dissolved in the organic solvent. A photopolymerizable nematic liquid crystal monomer ranging from 0.1 to 30 weight percent, a chiral compound soluble in the organic solvent ranging from 1 to 60 weight percent, and a chiral compound soluble in the organic solvent. The photoinitiator is 0.1 to 10 weight percent and the thermal polymerization inhibitor is 0.01 to 10 weight percent and is dissolved in the organic solvent.

7. The reflective polarizer according to claim 1, characterized in that the cholesteric liquid crystal solution includes: an organic solvent, a nematic liquid crystal with a weight percentage of 64.8% dissolved in the organic solvent, and a nematic liquid crystal dissolved in the organic solvent. A photopolymerizable nematic liquid crystal monomer with a weight percentage of 15.0 in the solvent, a chiral compound with a weight percentage of 14.8 in the organic solvent, a photoinitiator and a solvent with a weight percentage of 4.4 in the organic solvent. The weight percentage of the thermal polymerization inhibitor in the organic solvent is 1.0.

8. The reflective polarizing plate according to any one of claims 17, characterized in that the photopolymerizable nematic liquid crystal monomer is selected from the group consisting of acrylates, methacrylates, styryls, and diacetyl. Any one or a mixture of two or more base classes.

9. The reflective polarizing plate according to any one of claims 1 to 7, characterized in that the chiral compound is selected from any one or a mixture of two or more of R811, S811, CB15, and ZLI4572.

10. The reflective polarizing plate according to any one of claims 1 to 7, characterized in that the photoinitiator is selected from the group consisting of diphenyl peroxide, dodecanoyl peroxide, and azobisisobutyronitrile. , any one of diisopropyl peroxydicarbonate and dicyclohexyl peroxydicarbonate; the thermal polymerization inhibitor is selected from hydroquinone, p-quinone, 2-tert-butylhydroquinone, 2 , any one of 5-di-tert-butylhydroquinone.

11. The reflective polarizing plate according to any one of claims 1 to 7, characterized in that the organic solvent is selected from ethanol, acetone, dichloromethane, chloromethane, carbon tetrachloride, and tetrahydrofuran , isopropyl alcohol, cyclohexane, benzene, toluene, or any one of xylene.

12. The reflective polarizing plate according to any one of claims 1 to 7, characterized in that the spacers are glass beads with a diameter of 10 microns to 300 microns.

13. A method of preparing a reflective polarizer, characterized by including:

disposing a first alignment film on the first substrate;

Coating the chiral discotic liquid crystal solution on the first alignment film to prepare a chiral coating, wherein the chiral discotic liquid crystal solution at least includes photopolymerizable chiral discotic liquid crystal dissolved in an organic solvent Monomers, photoinitiators and thermal inhibitors;

The first substrate and the second substrate provided with the second alignment film are paired together to form a thin film device, and a spacer is provided between the chiral coating and the second alignment film of the second substrate to form a gap;

Cholesterol phase liquid crystal is injected into the gap, wherein the cholesteric phase liquid crystal is volatilized by the cholesteric phase liquid crystal solution. Preparation, the cholesteric liquid crystal solution at least includes an organic solvent, nematic liquid crystal, photopolymerizable nematic liquid crystal monomer, chiral compound, photoinitiator and thermal polymerization inhibitor;

The thin film device is subjected to heat treatment and light irradiation treatment to make a reflective polarizer.

14. The method of preparing a reflective polarizer according to claim 13, wherein the thin film device is subjected to heat treatment and light irradiation treatment to make a reflective polarizer, including:

Raise the temperature of the thin film device to a range of 90°C-120°C, preheat for 1 minute to 60 minutes, and perform UV irradiation polymerization and cross-linking. The UV irradiation time is 1 minute to 60 minutes, and the UV wavelength is 365 nanometers. , the irradiation dose is 0.001 milliwatts per square centimeter to 100 milliwatts per square centimeter to make a reflective polarizer.

15. The method of preparing a reflective polarizer according to claim 13, wherein the thin film device is subjected to heat treatment and light irradiation treatment to make a reflective polarizer, including:

The thin film device was heated to 110°C, preheated for 30 minutes, and subjected to ultraviolet irradiation polymerization and cross-linking. The ultraviolet irradiation time was 30 minutes, the ultraviolet wavelength was 365nm, and the irradiation dose was 10 milliwatts per square centimeter to produce into a reflective polarizer.

16. The method of preparing a reflective polarizer according to any one of claims 13-15, characterized in that the injecting cholesteric liquid crystal into the gap of the thin film device includes:

Cholesteric liquid crystal is injected into the gap under vacuum, where the cholesteric liquid crystal is oriented parallel to the array substrate.

17. A liquid crystal display device, including an array substrate, a color filter substrate parallel to the array substrate and disposed opposite the array substrate, and a liquid crystal layer disposed between the array substrate and the color filter substrate, characterized in that it also includes:

The reflective polarizing plate of claims 1-12 is provided on the side of the array substrate opposite to the liquid crystal layer, and is provided on the side of the color filter substrate opposite to the liquid crystal layer.