KR20080090659A - Cholesteric liquid crystal polymer, color compensating film and filter comprising the same, and display device having the film or the filter - Google Patents

Abstract

A cholesteric liquid crystal polymer, a color-correcting film comprising the cholesteric liquid crystal polymer, and an image display device comprising the color-correcting film are provided to block wavelengths of an orange light region efficiently and raise the transmittance of wavelengths of a visible light region. A color-correcting film(1) comprises a transparent base(10) and a cholesteric liquid crystal layer(20). The cholesteric liquid crystal layer contains cholesteric liquid crystal polymers. The cholesteric liquid crystal layer is composed of a first cholesteric liquid crystal layer(21) and a second cholesteric liquid crystal layer(22). If the first cholesteric liquid crystal layer is levorotary and the second cholesteric liquid crystal layer is dextrorotary, orange light is effectively blocked. Fifty percent of orange light is reflected in an incident direction by the first cholesteric liquid crystal layer, and remaining fifty percent of the orange light, which passes through the first cholesteric liquid crystal layer, is again reflected by the second cholesteric liquid crystal layer. The first cholesteric liquid crystal layer is disposed on one surface of the transparent base. The second cholesteric liquid crystal layer is disposed on the other surface of the transparent base.

Description

Cholesteric liquid crystal polymer, color compensating film and filter comprising the same, and display device having the film or the filter}

1 is a cross-sectional view showing a color correction film according to an embodiment of the present invention.

2 is a cross-sectional view showing a color correction film according to another embodiment of the present invention.

3 is a conceptual diagram for explaining the structure and operation of the cholesteric liquid crystal polymer.

Figure 4 is a schematic diagram showing the role of the color correction film according to an embodiment of the present invention.

5 is a spectrum showing the performance of the color correction film of FIG.

6 is a spectrum illustrating the performance of the color correction film of FIG. 2.

<Explanation of symbols for main parts of the drawings>

1: Color Correction Film 2: Image Display

10: transparent substrate 20: cholesteric liquid crystal layer

21: first cholesteric liquid crystal layer 22: second cholesteric liquid crystal layer

The present invention relates to a cholesteric liquid crystal polymer, a color correction film and a color correction filter including the same, and an image display device including the color correction film or the filter. An excellent cholesteric liquid crystal polymer, a color correction film and a color correction filter including the same, and an image display device including the color correction film or the filter.

Recently, many kinds of image display devices have been developed and put into practical use. Such image display devices are, for example, liquid crystal image display devices (LCDs), plasma display panels (PDPs), electroluminescent displays (FEDs), and cathode ray tube image display devices. (CRT), fluorescent display tubes, field emission display panels. Such image display devices display color images by implementing three primary colors of red, blue, and green in principle.

By the way, there is a problem in that light of an unnecessary wavelength is generated from the image display device to lower the purity of color. In particular, a decrease in the purity of red light due to the unique orange light emitted from the plasma display panel is problematic. This orange light is a unique visible light having a wavelength range of 550-650 nm generated when the neon atom is returned from the plasma display panel to the ground state after excitation.

As described above, in order to improve the problem of lowering the color purity of the image display device due to orange light, a color correction film for correcting the color purity is provided on one surface of the image display device. The main function of this color correction film is to remove the orange light.

Currently, a color correction film generally used in general has a structure in which a neon-cut pigment having a maximum absorption wavelength at 560-650 nm is added to a polymer resin and coated on a transparent substrate. For example, Korean Patent Laid-Open Publication No. 2006-0059787 discloses a method of manufacturing a color correction film for a plasma display panel using a cyanine dye as a neon-cut dye. In addition, Korean Patent Laid-Open Publication No. 2005-0121492 discloses a fluorescence removal method of a cyanine-based or porphyrin-based pigment and a method of manufacturing a color correction film using this method. However, as in the above methods, the color correction film using a pigment has a large maximum absorption wavelength and a full width at half maximum (FWHM), and insufficient blocking of orange light due to neon light emission or emission of fluorescence results in an image display device. Has the disadvantage of degrading the contrast and color reproducibility of the image.

In addition, such a neon-cut pigment has a problem of poor storage stability such as deterioration in durability when stored for a long time at high temperature and high humidity conditions. That is, the color correction film using the neon-cut pigment is not excellent in durability.

It is an object of the present invention to provide a cholesteric liquid crystal polymer having improved durability while efficiently blocking orange light.

Another object of the present invention is to provide a color correction film containing the cholesteric liquid crystal polymer.

Still another object of the present invention is to provide a color correction filter including the cholesteric liquid crystal polymer or the color correction film.

Still another object of the present invention is to provide an image display device having improved color purity by providing the color correction film or the filter.

According to the invention,

A cholesteric liquid crystal polymer is prepared by polymerizing 100 parts by weight of a nematic liquid crystal compound and 5 to 10 parts by weight of a chiral compound having at least one chiral center, and having a selective reflection center wavelength of 550 nm to 650 nm.

According to one embodiment of the invention, 5 to 7 parts by weight of the photoinitiator is used with respect to 100 parts by weight of the nematic liquid crystal compound as a polymerization initiator.

Also according to the invention,

Transparent substrates; And

At least one cholesteric liquid crystal layer containing a cholesteric liquid crystal polymer is disposed on at least one surface of the transparent substrate, and the cholesteric liquid crystal polymers contained in the adjacent cholesteric liquid crystal layers are each circularly polarized light reflected. There is provided a color correction film in opposite directions.

According to one embodiment of the invention, the cholesteric liquid crystal layer, the first cholesteric liquid crystal layer disposed on the transparent substrate, and the second cholesteric liquid crystal disposed on the first cholesteric liquid crystal layer Layer.

According to another embodiment of the present invention, the cholesteric liquid crystal layer, the first cholesteric liquid crystal layer disposed on one surface of the transparent substrate, and the second cholesteric liquid crystal disposed on the other surface of the transparent substrate Layer.

According to another embodiment of the present invention, the cholesteric liquid crystal polymer is formed by polymerizing 5 to 10 parts by weight of a chiral compound having at least one chiral center with respect to 100 parts by weight of a nematic liquid crystal compound, and selective reflection A color correction film is provided, characterized in that the center wavelength is 550 nm to 650 nm.

According to another embodiment of the present invention, the nematic liquid crystal compound and the chiral compound are difunctional acrylic compounds represented by the following Chemical Formulas 1 and 2, respectively.

Also according to the invention,

A color correction filter including a cholesteric liquid crystal polymer according to any one of the above embodiments is provided.

Also according to the invention,

A color correction filter including a color correction film according to any one of the above embodiments is provided.

Also according to the invention,

There is provided an image display device having a color correction filter according to any one of the above embodiments.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a cross-sectional view showing a color correction film according to an embodiment of the present invention, Figure 2 is a cross-sectional view showing a color correction film according to another embodiment of the present invention.

1 and 2, the color correction film 1 according to an embodiment of the present invention includes a transparent substrate 10 and a cholesteric liquid crystal layer 20.

As the transparent substrate 10, an organic polymer film such as polyethylene terephthalate (PET), polyvinyl alcohol (PVA), and triacetyl cellulose (TAC) is used.

The cholesteric liquid crystal layer 20 includes a cholesteric liquid crystal polymer, which will be described later, and includes a first cholesteric liquid crystal layer 21 and a second cholesteric liquid crystal layer 22. The first cholesteric liquid crystal layer 21 and the second cholesteric liquid crystal layer 22 may be left rotatable or left rotatable. However, when the first cholesteric liquid crystal layer 21 is left rotatable, the second cholesteric liquid crystal layer 22 is preferably right rotatable (dextro) in terms of blocking orange light. By including the transparent substrate 10 and the first and second cholesteric liquid crystal layers 21 and 22 as described above, the color correction film 1 transmits the incident orange light from the first cholesteric liquid crystal layer 21. About 50% of the light is reflected in the incident direction, and the remaining 50% of the orange light transmitted through the first cholesteric liquid crystal layer 21 is reflected back from the second cholesteric liquid crystal layer 22, thereby theoretically 100% Orange light reflectance is achieved. The orange light reflection principle in the cholesteric liquid crystal layer 20 will be described later.

The cholesteric liquid crystal layer 20 may have at least one layer disposed on the transparent substrate 10 in various structures. For example, in the cholesteric liquid crystal layer 20, as shown in FIG. 1, the first cholesteric liquid crystal layer 21 is disposed on the transparent substrate 10, and the first cholesteric liquid crystal is disposed. The second cholesteric liquid crystal layer 22 may be disposed on the layer 21. In addition, as shown in FIG. 2, the cholesteric liquid crystal layer 20 includes a first cholesteric liquid crystal layer 21 disposed on one surface of the transparent substrate 10, and the transparent substrate 10. The second cholesteric liquid crystal layer 22 may be disposed on the other surface of the substrate. In addition, two or more first and second cholesteric liquid crystal layers 21 and 22 may be disposed on the transparent substrate 10, respectively.

The cholesteric liquid crystal polymer is formed by polymerizing a nematic liquid crystal compound and a chiral compound having at least one chiral center.

The nematic liquid crystal compound is composed of long rod-shaped molecules and has no regularity at the center of the molecule, but has an order in the direction of the molecular axis. Since each nematic molecule can move freely in the long axis direction, the viscosity is small and the fluidity is good. Since the directions of the nematic molecules are almost equal in the up and down directions, the polarization is canceled out and thus generally does not exhibit ferroelectricity. In nematic liquid crystal compounds, molecular arrangements vary depending on temperature, electric field, or magnetic field. It is preferable that such a nematic liquid crystal compound is curable, and all can use it if it contains a mesogenic group. The liquid crystal compound has a long and hard structure in the middle part, and the end part is composed of long chains. The hard part in the middle part is called mesogen structure, and the chain part at the end of the molecule is called a flexible lattice. Mesogenic groups usually contain several ring structures, such as cycloalkane or aromatic rings, in which rings are interconnected by esters, carbonyl bonds, and the like. Flexible terminals, such as alkyl groups, alkoxy groups, and vinyl groups, may be bonded to the ends at various lengths. The flexible lattice may be bonded to both ends of the molecule, or may be bonded to only one side. In addition, the nematic liquid crystal compound is preferably a bifunctional acrylic compound represented by the following Chemical Formula 1, but the present invention is not limited thereto. Here, a bifunctional acryl-type compound means the compound which has two acryl groups in a molecule | numerator.

 [Formula 1]

Wherein m is 1 to 8, Ar is arylene unsubstituted or substituted with a halogen atom, a hydroxyl group, a cyan group, or an alkyl group having 1 to 5 carbon atoms.

A chiral compound is a symmetrical structure of three-dimensional structure like the relationship between the right hand and the left hand, and is a chemical substance having the same chemical structure and physical properties but not having the same three-dimensional structure due to its mirror image relationship. It is preferable that a chiral compound is also curable, and if it is a substance which has normal chiral carbon, all can be used, and it does not restrict | limit especially. In addition, the chiral compound is preferably a bifunctional acrylic system represented by the following Chemical Formula 2, but the present invention is not limited thereto.

 [Formula 2]

Wherein n is 1 to 8, Ar is arylene unsubstituted or substituted with a halogen atom, a hydroxyl group, a cyan group, or an alkyl group having 1 to 5 carbon atoms.

In this embodiment, the curable means thermosetting or ultraviolet curing. In the case of thermosetting, the nematic liquid crystal compound or chiral compound may be a combination of a monomer having a reactive group such as a vinyl group, an acryl group, a methacryl group, a vinylidene group, or an allyl group, or various reactive groups capable of condensation polymerization. Can be. In addition, in the case of UV curing, the compounds may be a combination of monomers having a reactive group crosslinkable by ultraviolet light such as vinyl group, acrylic group, methacryl group, vinylidene group, or allyl group.

The cholesteric liquid crystal polymer is formed to include 5 to 10 parts by weight of the chiral compound having at least one chiral center with respect to 100 parts by weight of the nematic liquid crystal compound, and the selective reflection center wavelength is 550 nm to 650 nm. Depending on the rotational direction of the chiral compound used, the rotational direction of the cholesteric liquid crystal polymer formed as a result of polymerization is different. That is, when the left rotatable chiral compound is polymerized with the nematic liquid crystal compound, the left rotatable cholesteric liquid crystal polymer is formed, and when the right rotatable chiral compound is polymerized with the nematic liquid crystal compound, the right rotatable cholesteric liquid crystal polymer is formed. Will be.

The cholesteric liquid crystal polymer has a structure in which nematic structural units represented by the following Chemical Formula 3 and chiral structural units represented by the following Chemical Formula 4 are randomly bonded in a ratio of 100: 5 to 100: 10.

[Formula 3]

 Wherein m is 1 to 8, Ar is arylene unsubstituted or substituted with a halogen atom, a hydroxyl group, a cyan group, or an alkyl group having 1 to 5 carbon atoms, and R is hydrogen or a methyl group.

[Formula 4]

Wherein n is 1 to 8, Ar is aryl unsubstituted or substituted with a halogen atom, a hydroxyl group, a cyan group, or an alkyl group having 1 to 5 carbon atoms, and R is hydrogen or a methyl group.

The cholesteric liquid crystal polymer thus formed forms a thin layer and each layer has a two-dimensional nematic structure composed of one layer of molecules. Here, the molecules in each layer have long axes arranged along the layer plane and each axis is parallel to each other. One of the unique optical properties of these cholesteric liquid crystal polymers is circular dichroism, which is the splitting of the beam of light. One wavelength is circularly polarized and the other is reflected. . Therefore, when white light is irradiated to the cholesteric liquid crystal polymer, the reflected beam has a characteristic of displaying a rainbow color according to the angle of the incident beam.

3 is a conceptual diagram for explaining the structure and operation of the cholesteric liquid crystal polymer.

As shown in FIG. 3, the cholesteric liquid crystal polymer repeats twisting of molecules at regular intervals. The repeated length is called pitch (p), and light causes Bragg reflection by the repeated structure. Here, Bragg reflection has a reflectance of about 50% rather than total reflection. That is, about 50% of light of a specific wavelength incident on the cholesteric liquid crystal polymer is reflected and the remaining about 50% is helically passed through the cholesteric liquid crystal polymer by the twisted molecular structure in the pitch p. Therefore, when the right turn cholesteric liquid crystal layer is disposed on the left turn cholesteric liquid crystal layer, light of a specific wavelength passing through one cholesteric liquid crystal layer does not pass through the other cholesteric liquid crystal layer, but is totally reflected. This is because the twisted direction of the molecules in the pitch p of the left-rotating cholesteric liquid crystal layer is opposite to the twisted direction of the molecules in the pitch p of the right-rotating cholesteric liquid crystal layer.

In the present embodiment, when the cholesteric liquid crystal polymer is polymerized as described above, horizontal alignment is induced and thus has selective reflection characteristics. Therefore, in this embodiment, a separate horizontal orientation induction method such as a gradient deposition method, a rubbing method, or an electric application method is unnecessary. Here, the gradient deposition method is a method of applying a cholesteric liquid crystal polymer on a transparent substrate and then applying an alignment agent thereon, and the rubbing method is a liquid crystal polymer in a predetermined direction after applying the cholesteric liquid crystal polymer on a transparent substrate It means rubbing the surface or the like to orient it.

In this embodiment, the selective reflection center wavelength of the cholesteric liquid crystal polymer was adjusted to 550 nm to 650 nm, preferably 590 nm to block the orange light. Since the wavelength range is a wavelength range corresponding to orange light, it is not preferable to leave a range of visible light in addition to the orange light because it is out of this range. The selective reflection center wavelength is controlled by controlling the polymerization ratio of the nematic liquid crystal compound and the chiral compound. That is, by polymerizing at a ratio of 5 to 10 parts by weight of the chiral compound with respect to 100 parts by weight of the nematic liquid crystal compound, the selective reflection center wavelength of the cholesteric liquid crystal polymer is adjusted to 550 nm to 650 nm. When it is out of the polymerization ratio range, the result is out of the range of the selective reflection center wavelength, so it is impossible to achieve the object of the present invention to block the orange light.

The cholesteric liquid crystal polymer is also polymerized using a photoinitiator, and the amount of photoinitiator is preferably 5 to 7 parts by weight based on 100 parts by weight of the nematic liquid crystal compound. Photoinitiators generate radicals by ultraviolet light (200-450 nm), which radicals react with monomers, ie nematic liquid crystal compounds and chiral compounds, to cause polymerization. Photopolymerization initiators, which usually have absorption bands in the ultraviolet region of 250 nm to 450 nm, include carbonyl compounds, sulfur compounds, and azo compounds, but mainly carbonyl compounds are used. Photoinitiators are classified into radical reaction type and ionic reaction type depending on the polymerization initiation mechanism. The polymerization initiator of the present invention is not limited to photoinitiators, and various other initiators can be used.

The polymerization of the cholesteric liquid crystal polymer may further include a leveling agent, and the content thereof is preferably 0.01 to 0.1 parts by weight based on 100 parts by weight of the nematic liquid crystal compound. The leveling agent further controls the coating film thickness of the cholesteric liquid crystal polymer applied to the transparent substrate to improve the uniformity of the coating film thickness. As such a leveling agent, silicone type surfactants, such as a nonionic surfactant, polyether modified silicone, or fluoropolyether comodified silicone, are mainly used.

In addition to the photoinitiator and leveling agent, other various additives may be used as necessary.

Hereinafter, a method of manufacturing a color correction film by laminating a cholesteric liquid crystal polymer having the above configuration on a transparent substrate will be described in detail.

(1) A nematic liquid crystal compound and a chiral compound are dissolved in an organic solvent to prepare a mixed solution. Although the ketone solvent was used as the organic solvent in the present embodiment, the present invention is not limited thereto.

(2) Additives, such as a photoinitiator and a leveling agent, are added to the said mixed solution.

(3) A thin film is applied onto the transparent substrate by a method such as roll coating, dip coating or spray coating.

(4) The transparent substrate coated with the mixed solution is introduced into a drier to evaporate the organic solvent.

(5) The cholesteric liquid crystal polymer is obtained by irradiating the transparent substrate with UV light to polymerize the nematic liquid crystal compound and the chiral compound. As a result, a cholesteric liquid crystal layer is formed on the transparent substrate.

The above is a method of laminating one cholesteric liquid crystal layer on a transparent substrate, and a method of manufacturing a color correction film by laminating two or more layers of cholesteric liquid crystal layers on a transparent substrate is as follows. It will be different together.

For example, as shown in FIG. 1, a method of manufacturing a color correction film by laminating two cholesteric liquid crystal layers on a transparent substrate is as follows.

First, the first cholesteric liquid crystal layer is laminated on the transparent substrate according to the lamination method of (1) to (5), and then the second cholesteric liquid crystal layer is formed on the other transparent substrate (1). It laminates according to the lamination method of (5). Thereafter, the laminated two transparent substrates are laminated using an adhesive (not shown), followed by thermosetting in a dryer, and then peeling the transparent substrate in one direction to complete the color correction film. Note that the first cholesteric liquid crystal layer and the second cholesteric liquid crystal layer are laminated so as to contact each other when laminating the laminated two transparent substrates.

As another example, as shown in FIG. 2, a method of laminating a total of two layers of cholesteric liquid crystal layers, one on each side of the transparent substrate, is as follows.

First, the first cholesteric liquid crystal layer is laminated on one surface of the transparent substrate according to the lamination method of (1) to (5).

Next, a second cholesteric liquid crystal layer is laminated on the other surface of the transparent substrate according to the lamination method of (1) to (5) above to complete the color correction film.

Figure 4 is a schematic diagram showing the role of the color correction film according to an embodiment of the present invention.

Hereinafter, the role of the color correction film 1 according to the present embodiment will be described in detail with reference to FIG. 4.

As shown in FIG. 4, when the color correction film 1 is provided in the image display device 2, the visible light of R, G, and B emitted from the image display device 1 is used as the color correction film 1. It transmits, and orange light of 550-650 nm wavelength band is interrupted | blocked. The color correction film 1 is usually laminated so that the left rotatable cholesteric liquid crystal layer and the right rotatable cholesteric liquid crystal layer are paired, and the reason is as described above.

In addition, the color correction film 1 according to the present embodiment may be employed in the light blocking filter. Such a light blocking filter may include various films such as a near infrared blocking film in addition to the color correction film. In addition, the light blocking filter may be composed of an integrated film by simultaneously introducing a cholesteric liquid crystal polymer and a near infrared absorbing dye. In this case, there is an advantage that the manufacturing process of the light blocking filter is reduced.

Here, the light blocking filter is limited to the color correction filter.

The color correction filter according to the present embodiment may further include an antireflection film (AR film), an electromagnetic shielding film (EMI film), and a black screen treatment layer. The color correction filter not only blocks orange light. It functions as image display device protection, antireflection, and electromagnetic wave blocking.

The present invention also provides an image display device including the color correction filter.

Hereinafter, the present invention will be described in more detail with reference to preferred embodiments, but the present invention is not limited thereto.

Example

Preparation of color correction film

Example 1

A color correction film having a laminated structure of FIG. 1 was prepared as follows.

Example 1-A: formation of a right-rotating cholesteric liquid crystal layer on a transparent substrate

First, 200 g of a bifunctional acrylic nematic liquid crystal compound (BASF, LC242) of Formula 5 and 13.4 g of a bifunctional acrylic right-turning chiral compound (BASF, LC756) of Formula 6, 64 g of methyl isobutyl ketone (MIBK) And 256 g of methyl ethyl ketone (MEK) were mixed with the mixed organic solvent to prepare a mixed solution.

[Formula 5]

[Formula 6]

Thereafter, 11 g of a photoinitiator (Ciba-Geigy, IG-907) and 0.11 g of a leveling agent (Ciba-Geigy, Tego-Rad 2100) were mixed with the mixed solution. The mixed solution was thin-film coated on a polyethylene terephthalate (PET) film (transparent substrate) by a roll coating method. Thereafter, the thin film coated film was put in a dryer to evaporate the organic solvent. Next, UV light was irradiated to form a cholesteric liquid crystal layer. At this time, the drying temperature was 90 ℃, UV light irradiation was performed using a 300W (center wavelength 360nm) lamp. The selective reflection center wavelength of the formed right-rotating cholesteric liquid crystal layer was 590 nm, and the thickness was 2.5-3.0 micrometers.

Example 1-B: Left-rotating cholesteric liquid crystal layer formed on another transparent substrate

The selective reflection central wavelength was 590 nm and the thickness was 2.5-3.0 μm in the same manner as in Example 1-A, except that 16.2 g of a bifunctional acrylic left-rotating chiral compound (BASF, LC766) corresponding to Chemical Formula 6 was used. A phosphorus left rotatable cholesteric liquid crystal layer was prepared.

Example 1-C: Color Correction Film Formation

The film on which the right rotational cholesteric liquid crystal layer was formed and the film on which the left rotational cholesteric liquid crystal layer was formed were laminated using an adhesive. At this time, the lamination direction was a direction in which the right rotational cholesteric liquid crystal layer and the left rotational cholesteric liquid crystal layer were in contact with each other. The laminated film was thermally cured in a dryer for about 4 hours, and then the polyethylene terephthalate (PET) film in one direction was peeled off. The thickness of all the formed cholesteric liquid crystal layers was 5-6 micrometers.

As a result, a color correction film having the structure of FIG. 1 was obtained.

Example 2

A color correction film having a laminated structure of FIG. 2 was prepared as follows.

Example 2-A: formation of a right-rotating cholesteric liquid crystal layer on one surface of a transparent substrate

In the same manner as in Example 1-A, a right-rotating cholesteric liquid crystal layer having a selective reflection center wavelength of 590 nm and a thickness of 2.5-3.0 μm was formed.

Example 2-B: Left-rotating cholesteric liquid crystal layer formed on the other surface of the transparent substrate

The selective reflection center wavelength is 590 nm and the thickness is 2.5-3.0 μm in the same manner as in Example 2-A, except that 16.2 g of a bifunctional acrylic left-rotating chiral compound (BASF, LC766) corresponding to Formula 6 is used. A phosphorus left rotatable cholesteric liquid crystal layer was formed on the other surface of the PET film (transparent substrate).

As a result, a color correction film having the structure of FIG. 2 was obtained.

Test Example 1

For the color correction films prepared in Examples 1 and 2, the UV-VIS spectrum was taken after 500 hours at 60 ° C. and 90% relative humidity to evaluate the color correction performance and durability of the film. Are shown in FIGS. 5 and 6. In general, the durability of a color correction film is determined by the rate of change after measuring the initial transmittance and then exposing it for a certain period of time under high temperature or high humidity conditions. The change in transmittance is excellent in durability. have.

5 is a spectrum showing the performance of the color correction film of FIG. 1 (Example 1), and FIG. 6 is a spectrum showing the performance of the color correction film of FIG. 2 (Example 2).

5 and 6, it was shown that the color correction films of Examples 1 and 2 block about 71% of the wavelength (550-650 nm) of the orange light region. Therefore, when such a film is employed in the image display device, the color purity improving effect is increased. This result is also obtained after leaving the color correction film for a long time in the high temperature and humidity conditions of Test Example 1, and also demonstrates the fact that the durability of the color correction film according to the present embodiments is very excellent.

On the other hand, in the case where only the cholesteric liquid crystal layers having the same rotational direction are stacked in duplicate, the wavelength transmittance of the visible light region is similar to those of Examples 1 and 2, but the wavelength blocking ratio of the orange light region is the cholesteric liquid crystal polymer described above. Only about half of the case of Examples 1 and 2 in view of the optical properties. From this, it can be seen that the color correction film is preferably used by laminating at least a pair of cholesteric liquid crystal layers having opposite directions of rotation.

As described above, according to the present invention, a cholesteric liquid crystal polymer capable of effectively blocking the wavelength of the orange light region and increasing the transmittance of the wavelength of the visible light region can be provided.

In addition, according to the present invention may be provided a color correction film containing the cholesteric liquid crystal polymer.

According to the present invention, a color correction filter including the cholesteric liquid crystal polymer or the color correction film may be provided.

In addition, according to the present invention, by providing the color correction film or the filter can be provided with an image display device improved color purity improvement effect.

Claims (9)

A cholesteric liquid crystal polymer having a structure in which nematic structural units and chiral structural units are irregularly bonded in a ratio of 100: 5 to 100: 10, and the selective reflection center wavelength is 550 nm to 650 nm. The method of claim 1, The nematic liquid crystal compound and the chiral compound are cholesteric liquid crystal polymers, characterized in that the difunctional acrylic system represented by the following formula (1) and (2), respectively. [Formula 1]

Wherein m is 1 to 8, Ar is arylene unsubstituted or substituted with a halogen atom, a hydroxyl group, a cyan group, or an alkyl group having 1 to 5 carbon atoms. [Formula 2]

Wherein n is 1 to 8, Ar is arylene unsubstituted or substituted with a halogen atom, a hydroxyl group, a cyan group, or an alkyl group having 1 to 5 carbon atoms. Transparent substrates; And At least one cholesteric liquid crystal layer containing the cholesteric liquid crystal polymer of claim 1 is disposed on at least one surface of the transparent substrate, and the cholesteric liquid crystal polymers contained in the cholesteric liquid crystal layers are circularly polarized. Color correction films with opposite directions of reflection. The method of claim 3, The cholesteric liquid crystal layer comprises a first cholesteric liquid crystal layer disposed on the transparent substrate, and a second cholesteric liquid crystal layer disposed on the first cholesteric liquid crystal layer. Correction film. The method of claim 3, The cholesteric liquid crystal layer includes a first cholesteric liquid crystal layer disposed on one surface of the transparent substrate, and a second cholesteric liquid crystal layer disposed on the other surface of the transparent substrate. Correction film. The method according to any one of claims 3 to 5, The color correction film is a color correction film, characterized in that for the plasma display panel. A color correction filter comprising the color correction film according to any one of claims 3 to 5. An image display device comprising the color correction filter according to claim 7. The method of claim 8, And the image display device is a plasma display panel.

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