KR20170101543A

KR20170101543A - Polarizing plate

Info

Publication number: KR20170101543A
Application number: KR1020160024206A
Authority: KR
Inventors: 이대희; 김영진; 이은혜; 박문수; 장준원
Original assignee: 주식회사 엘지화학
Priority date: 2016-02-29
Filing date: 2016-02-29
Publication date: 2017-09-06
Also published as: KR102006381B1

Abstract

The present application is directed to a polarizing plate comprising a hazy liquid crystal film. The polarizing plate of the present application can impart a haze property to a polarizing plate even by a simple process compared to other processes.

Description

Polarizing plate {

This application is directed to polarizers and their uses.

The liquid crystal display (LCD) may include a liquid crystal panel and a polarizing plate disposed on the upper side and the lower side of the liquid crystal panel, and may include various functional optical elements in addition to the polarizing plate.

The polarizing plate included in the LCD can be classified into an absorption type or a reflection type polarizing plate in general, and can have a predetermined haze.

Patent Document 1 is a document which includes predetermined particles for inducing a scattering effect in a liquid crystal layer included in a polarizing plate, and Patent Document 2 is a document for implementing haze through orientation of a cholesteric liquid crystal layer.

However, in the method of implementing the haze of the polarizing plate as in Patent Documents 1 and 2, there are some complications of the process and difficulties in the operation, and there are various constraint conditions for realizing the desired haze, and the desired scattering effect and haze A new method for assigning a new value is required.

Registered patent KR 1155878 Registered patents KR 1251248

The present application provides a polarizing plate, a method for producing the same, and uses thereof.

The present application relates to a polarizing element; And a polarizing plate comprising a liquid crystal film. The liquid crystal film is positioned on a polarizing element, and includes a liquid crystal compound and a surfactant, and has a haze within a range of 5% to 50%.

The present application also relates to a polarizing plate manufacturing method comprising forming a liquid crystal film having a haze within a range of 5% to 50% by using a liquid crystal film forming composition containing a liquid crystal compound and a surfactant on a polarizing element will be.

The present application further relates to a use of the polarizing plate, for example, an optical element including a polarizing plate.

The polarizing plate of the present application is simpler in process than the various known methods for achieving a desired haze, and is advantageous from the viewpoint of productivity of a product.

1 to 5 are schematic diagrams of a polarizing plate according to the present application.
6 is a microscope photograph of a liquid crystal film according to an embodiment of the present application.

The present application relates to a polarizing plate, a method for producing the same, and a use thereof.

The polarizing plate of the present application is superior to other polarizing plate manufacturing methods for realizing a desired haze by including a scattering particle or the like by placing a liquid crystal film having a predetermined haze on a polarizing element including a liquid crystal compound and a surfactant The process efficiency can be improved. Such a polarizing plate is an absorption type or reflection type polarizing plate, and may be included on, for example, any one side of a liquid crystal panel for an LCD.

The polarizing plate of the present application comprises a polarizing element; And a liquid crystal film. The liquid crystal film is positioned on the polarizing element, and includes a liquid crystal compound and a surfactant, and has a haze within a range of 5% to 50%.

In the polarizing plate of the present application, a predetermined surfactant is contained on a polarizing element to position a liquid crystal film having a haze within a range of 5% to 50%, so that even if scattering particles are contained or alignment of the liquid crystal in the polarizing element is not controlled , The desired haze of the polarizer can be realized.

The present application includes a polarizing element.

The term " polarizing element " in the present application may mean a functional element exhibiting selective transmission and blocking characteristics, for example, reflection or absorption characteristics, with respect to incident light. For example, the polarizing element may have a function of transmitting light that vibrates in one direction from incident light that vibrates in various directions, and blocking light that vibrates in the other direction.

As the polarizing element of the present application, for example, an absorption type polarizing element or a reflection type polarizing element can be exemplified.

In one example, the polarizing element may be an absorbing polarizing element. The absorption type polarizing element may include, for example, a stretched layer of polyvinyl alcohol (PVA) in which a dye is dyed.

The absorption type polarizing element using the polyvinyl alcohol (PVA) stretching layer is produced by dying a dye in a polyvinyl alcohol (PVA) resin and then stretching in a predetermined direction, whereby the dye dyed in the resin is stretched in the stretching direction And may mean a polarizing element that absorbs light to impart polarization characteristics.

The kind of the dye to be dyed in the polyvinyl alcohol (PVA) stretched layer, the method of dyeing, etc. are known, and the stretching magnification can be freely changed by a person skilled in the art .

In one example, the polyvinyl alcohol (PVA) stretching layer may be stretched to within a range of 1.1 to 2.5 times or 1.3 to 2.0 times in the machine transport direction or in the opposite direction to the machine transport direction, but is not limited thereto.

When the polarizing element includes, for example, a stretched layer of polyvinyl alcohol (PVA) in which a dye is dyed, a triacetylcellulose (TAC) layer for protecting the stretched layer is laminated on either or both sides of the stretched layer May be further included. 2, the polarizing plate has a triacetyl cellulose (TAC) layer 102 laminated on both sides of a stretching layer 101 of polyvinyl alcohol (PVA), and a liquid crystal film 200) may be located.

In addition, the triacetylcellulose (TAC) layer may be laminated directly to the stretched layer of the polyvinyl alcohol (PVA) or via a pressure-sensitive adhesive layer.

In another example, the polarizing element may be a reflective polarizing element. The reflection type polarizing element includes, for example, a laminate including a cholesteric liquid crystal layer; A mammary liquid crystal layer; A wire grid polarizing layer; And DBEF (Dual Brightness Enhancement Film). However, the present invention is not limited thereto, and it may have a structure of a multi-layer laminate such as DBEF, A known reflection type polarizing element capable of functioning can be used without limitation.

In one embodiment, the reflective polarizing element may be a laminate comprising a cholesteric liquid crystal layer and an optically anisotropic layer.

The cholesteric liquid crystal layer may include, for example, a cholesteric liquid crystal.

Specifically, the cholesteric liquid crystal has a spiral structure in which waveguides of liquid crystal molecules are twisted along a spiral axis and oriented in layers. The distance in which the spiral structure is rotated 360 degrees is called a pitch.

The cholesteric liquid crystal layer of the present application may include a plurality of regions including a pitch at which the helical structure of the liquid crystal molecules is rotated 360 degrees. In addition, the helical axis of the cholesteric liquid crystal present in the regions may be perpendicular to the polarizer.

In one example, the cholesteric liquid crystal layer comprises a cholesteric liquid crystal region, and the helical axis of the waveguide of the cholesteric liquid crystal molecules in the liquid crystal region may be perpendicular to the polarizer.

That is, the cholesteric liquid crystal layer may include a planar aligned region in which the helical axis of the cholesteric liquid crystal molecules is perpendicular to the liquid crystal layer.

Thus, the direction of the helical axis can further control the haze characteristic of the polarizing plate.

The laminate including the cholesteric liquid crystal layer may further include an optically anisotropic layer, which may be, for example, a quarter wavelength plate.

3, when the polarizing element included in the polarizing plate is a reflective polarizing element including a cholesteric liquid crystal layer, the polarizing plate includes a cholesteric liquid crystal layer 103 and a 1/4 wavelength plate And a liquid crystal film 200 formed on the polarizing element 100. The polarizing element 100 may be a reflective polarizing element including a polarizing element 100 and a liquid crystal film 200 formed on the polarizing element 100.

The polarizing plate of the present application includes a liquid crystal film. As shown in FIG. 1, the liquid crystal film 200 is positioned on the polarizing element 100. Further, as shown in Fig. 1, the liquid crystal film 200 may have at least one concavity and convexity 201.

The liquid crystal film of the present application may have a predetermined haze value due to the at least one unevenness.

That is, the liquid crystal film has a haze in the range of 5% to 50%. The haze may be a value measured by an ASTM method using a hazemeter such as HR-100 or HM-150 or NDH-5000SP of Sephoon Co., for example. In another example, the liquid crystal film may have a haze in the range of 10% to 45% or 15% to 40%.

The liquid crystal film includes a liquid crystal compound and a surfactant.

The liquid crystal film of the present application contains a surfactant in a predetermined ratio as compared with the liquid crystal compound, and by allowing the surfactant to aggregate the liquid crystal compound, predetermined irregularities can be imparted to the liquid crystal film, and ultimately, Lt; RTI ID = 0.0 > a < / RTI > desired haze value.

When a liquid crystal film is formed using a composition containing a liquid crystal compound and a surfactant in a predetermined ratio with respect to the liquid crystal compound, scattering particles may be included to realize haze or adjust the alignment characteristics of the liquid crystal compound to adjust the haze The manufacturing process is easier and the degree of freedom in process selection can be increased as compared with the implementation.

The liquid crystal compound contained in the liquid crystal film may be, for example, a polymer of a reactive mesogen.

That is, when the composition for forming a liquid crystal film contains a reactive mesogen, when a liquid crystal film is formed through a curing process or the like to be described later, the reactive sites of the reactive mesogens are bonded to each other to form one polymer layer have.

The term " reactive mesogen " in the present application may mean a reactor capable of inducing polymerization by light or heat, for example, a mesogen comprising a polymerizable functional group. The term " mesogen " refers to a meso phase compound capable of causing the layer to exhibit liquid crystal phase behavior when a liquid crystal compound such as the reactive mesogen is polymerized to form a layer. . &Lt; / RTI >

In one example, the reactive mesogen can be represented by the following formula (1).

[Chemical Formula 1]

Wherein A is a single bond, -COO- or -OCO-, and R ₁ to R ₁₀ are each independently selected from the group consisting of hydrogen, a halogen, an alkyl group, an alkoxy group, a cyano group, a nitro group, -OQP, Wherein at least one of R ₁ to R ₁₀ is -OQP or a substituent of the following formula 2, Q is an alkylene group or an alkylidene group, P is an alkenyl group, an epoxy group, a cyano group, a carboxyl group, an acryloyl group, A methacryloyl group, an acryloyloxy group or a methacryloyloxy group;

(2)

R ₁₁ to R ₁₅ each independently represents hydrogen, halogen, an alkyl group, an alkoxy group, a cyano group, a nitro group or -OQP, R ₁₁ to R ₁₅ each independently represent a hydrogen atom, At least one of them is -OQP wherein Q is an alkylene group or an alkylidene group and P is an alkenyl group, an epoxy group, a cyano group, a carboxyl group, an acryloyl group, a methacryloyl group, an acryloyloxy group, It is a sunny season.

In the above formula (2), "-" to the left of B means that B is directly connected to benzene of formula (1).

The term "single bond" in the above formulas (1) and (2) means a case where there is no separate atom in the part represented by A or B. For example, when A is a single bond in formula (I), benzene on both sides of A may be directly connected to form a biphenyl structure.

As the halogen in the formulas (1) and (2), chlorine, bromine or iodine and the like can be exemplified.

The alkyl group in the general formulas (1) and (2) is preferably a linear or branched alkyl group having from 1 to 20 carbon atoms, from 1 to 16 carbon atoms, from 1 to 12 carbon atoms, from 1 to 8 carbon atoms or from 1 to 4 carbon atoms or from 3 to 20 carbon atoms, A cycloalkyl group having 4 to 12 carbon atoms may be exemplified. In addition, the alkyl group may be optionally substituted by one or more substituents.

In the general formulas (1) and (2), an alkoxy group having 1 to 20 carbon atoms, 1 to 16 carbon atoms, 1 to 12 carbon atoms, 1 to 8 carbon atoms or 1 to 4 carbon atoms may be exemplified. The alkoxy group may be linear, branched or cyclic.

In addition, the alkoxy group may be optionally substituted with one or more substituents.

The alkylene group or the alkylidene group in the formulas (1) and (2) may be an alkylene group or an alkylidene group having 1 to 12 carbon atoms, 4 to 10 carbon atoms, or 6 to 9 carbon atoms. The alkylene group or alkylidene group may be linear, branched or cyclic. The alkylene or alkylidene group may be optionally substituted by one or more substituents.

The alkenyl groups in the general formulas (1) and (2) include an alkenyl group having 2 to 20 carbon atoms, 2 to 16 carbon atoms, 2 to 12 carbon atoms, 2 to 8 carbon atoms or 2 to 4 carbon atoms. The alkenyl group may be linear, branched or cyclic. In addition, the alkenyl group may be optionally substituted with one or more substituents.

Examples of the substituent which may be substituted in the above alkyl group, alkoxy group, alkenyl group, alkylene group or alkylidene group include alkyl group, alkoxy group, alkenyl group, epoxy group, cyano group, carboxyl group, acryloyl group, methacryloyl group, Acryloyloxy group, methacryloyloxy group, aryl group, and the like, but the present invention is not limited thereto.

In the formulas (1) and (2), P may be an acryloyl group, a methacryloyl group, an acryloyloxy group or a methacryloyloxy group.

-OQP, which may be present in at least one of the formulas (1) and (2), or the moiety of the formula (2) may be present at the position of, for example, R ₃ , R ₈ or R ₁₃ , One or two residues may be present. In the compound of formula 1 or the moiety of formula 2, substituents other than -OQP or the moiety of formula 2 include, for example, hydrogen, halogen, a straight or branched alkyl group of 1 to 4 carbon atoms, An alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a cyano group or a nitro group, preferably a chlorine, a straight or branched alkyl group having 1 to 4 carbon atoms, a cycloalkyl group having 4 to 12 carbon atoms, Lt; / RTI > alkoxy group or cyano group.

In a specific example, the liquid crystal compound may be at least one selected from the reactive mesogens represented by the following general formulas (3) to (7), but is not limited thereto.

(3)

[Chemical Formula 4]

[Chemical Formula 5]

[Chemical Formula 6]

(7)

Such a liquid crystal compound may be vertically aligned in, for example, a liquid crystal film. When the vertically aligned liquid crystal compound is contained in the liquid crystal film, it may be effective to realize a desired haze in the liquid crystal film, together with a predetermined content of a surfactant to be described later.

The liquid crystal film includes a surfactant capable of imparting cohesiveness to the liquid crystal compound.

The surfactant is contained in a predetermined proportion in the liquid crystal film to aggregate the liquid crystal compound, and ultimately has a function of controlling the haze of the liquid crystal film within the range of 5% to 50%.

Therefore, the surfactant contained in the liquid crystal film of the present application may be one having properties capable of appropriately aggregating the liquid crystal compound. In the structure of the surfactant, if the flexible portion is excessively long, the smoothness of the liquid crystal film may be improved rather than the purpose of the present application. Therefore, Active agents can be employed and used.

In one example, a fluorine-based surfactant or a silicon-based surfactant may be used as the surfactant.

In a specific example, the fluorine-based surfactant may be represented by the following general formula (8).

[Chemical Formula 8]

Wherein R ₁₆ and R ₁₇ are each independently hydrogen, fluorine, an alkyl group, an aryl group, an acryloyl group, a methacryloyl group, an acryloyloxy group, or a methacryloyloxy group; And y is an integer of 0 to 5.

The oxygen included in the formula (8) has a large angle of bonding and is more flexible than the carbon chain, so that the surface roughness of the liquid crystal film can be lowered. Therefore, when the y value is too high in the fluorine-based surfactant of the formula 3 of the present application, there is a fear of inhibiting the formation of agglomerates due to the bonding of the liquid crystal compound and the surfactant, and the unevenness of the entire liquid crystal film is reduced, Which may not be achieved. Therefore, in formula (3), y may preferably be 0 to 4, 0 to 3, 0 to 2 or 0.

As such a fluorochemical surfactant, for example, a commercially available Fluorad series of 3M may be used, but the present invention is not limited thereto.

As the silicone surfactant, for example, BYK-TM manufactured by BYK-Chemie may be used. However, it is not limited thereto, and appropriate types may be selected in consideration of the cohesiveness of the liquid crystal compound.

The surfactant may be included in the liquid crystal film within a range of 5 to 20 parts by weight based on 100 parts by weight of the liquid crystal compound. Within such a range, it is possible to realize a liquid crystal film in which the liquid crystal compound can aggregate to give a concave-convex structure in the liquid crystal film, and ultimately the haze is in the range of 5% to 50%. When the content of the surfactant is too small or the content is too large, the desired haze value can not be realized. Therefore, it is preferable that the surfactant is included in the liquid crystal film together with the liquid crystal compound within the above range.

The term " part by weight " in the present application may mean a weight ratio between the respective components, unless otherwise specified. When the liquid crystal compound is a polymer of a reactive mesogen, 100 parts by weight of the liquid crystal compound may mean 100 parts by weight of the reactive mesogen forming the polymer.

When the above liquid crystal compound and the surfactant are simultaneously contained in the liquid crystal film, the liquid crystal compound may be aggregated by the surfactant.

As described above, when a liquid crystal compound aggregated by a surfactant is included in the liquid crystal film, the liquid crystal film may have irregularities 201 on its surface, and may have a predetermined surface roughness.

In one example, the liquid crystal film may have a center line surface roughness (Ra) in the range of 100 nm to 10,000 nm. In another example, the liquid crystal film may have a center line surface roughness (Ra) in the range of 200 nm to 5,000 nm.

The liquid crystal film may have a single layer structure including, for example, the above-described liquid crystal compound and a surfactant, or may have a laminated structure of a base layer and a liquid crystal layer including a liquid crystal compound and a surfactant formed on the base layer .

The base layer plays a role of supporting the liquid crystal layer and may be a cellulose base material such as DAC (diacetyl cellulose) or TAC (triacetyl cellulose) base material; A cycloolefin copolymer (COP) base material such as a norbornene derivative resin base material; Polyolefin based materials such as polyethylene terephthalate (PBT), polyethylene terephthalate (PBT), polyethylene terephthalate (PBT), polyethylene terephthalate (polysulfone) substrate, a PAR (polyarylate) substrate, a fluororesin substrate, and the like, for example, a polyetheretherketone substrate, a polyetheretherketone substrate, a PEN substrate, a polyethylenenaphthatate substrate, The same plastic substrate can be used.

The thickness of the liquid crystal film may be, for example, in the range of 100 nm to 10,000 nm or 300 nm to 5,000 nm.

The liquid crystal film of the present application is capable of imparting a concavo-convex shape to the surface of the film without containing particles such as fillers due to the agglomeration of the liquid crystal compound due to the above-mentioned surfactant, and can realize a predetermined haze value, Roughness can be provided. That is, the liquid crystal film may not contain particles such as fillers having a size of 0.1 to 50 탆. Here, the particle may mean a shape including a sphere, an ellipsoid, a tetrahedron, a hexahedron, or a pillar.

The polarizing plate of the present application may further include a protective film.

The protective film may be a plastic substrate, for example, a cellulose substrate such as DAC (diacetyl cellulose) or TAC (triacetyl cellulose) substrate, which is the same as or different from the substrate layer of the liquid crystal film; A cycloolefin copolymer (COP) base material such as a norbornene derivative resin base material; Polyolefin based materials such as polyethylene terephthalate (PBT), polyethylene terephthalate (PBT), polyethylene terephthalate (PBT), polyethylene terephthalate (polyarylate) base material, a fluoro resin base material, or the like may be used as the base material, such as a polyetheretherketone base material, a polyetherimide base material, a PEN (polyethylenenaphthatate) base material, a polyester base material such as a PET (polyethyleneterephthalate) base material, Can be illustrated.

The protective film may be positioned, for example, between the polarizing element and the liquid crystal film.

4 and 5, the polarizing plate of the present application is formed on the polarizing element 100, the protective film 300 formed on the polarizing element 100, and the protective film 300 And a liquid crystal film (200) formed thereon.

The present application also relates to a method for producing a polarizing plate.

The method for producing a polarizing plate of the present application includes forming a liquid crystal film having a haze within a range of 5% to 50% by using a composition for forming a liquid crystal film containing a liquid crystal compound and a surfactant on a polarizing element.

The manufacturing process of the polarizing plate according to the present application is not limited to a method of realizing the haze of the polarizing plate including the scattering particles or the like or the method of realizing the haze of the polarizing plate by controlling the alignment of the liquid crystal, There is an advantage to implementing haze.

The method of forming a liquid crystal film on a polarizing element can be carried out, for example, by coating the composition on a polarizing element by using a known coating method for a composition for forming a liquid crystal film, And then a liquid crystal film is formed through a process such as curing to laminate with a polarizing element.

Such known coating methods include, for example, bar coating, gravure coating, reverse roll coating, reverse gravure coating, slot die coating, comma coating, spray coating, knife coating, die coating, dip coating, microgravure coating, But the present invention is not limited thereto.

The composition for forming a liquid crystal film may contain 5 to 20 parts by weight of a surfactant based on 100 parts by weight of the liquid crystal compound. The types of the liquid crystal compound and the surfactant are as described above.

The composition for forming a liquid crystal film may further include a solvent.

Examples of the solvent include halogenated hydrocarbons such as chloroform, dichloromethane, tetrachloroethane, trichlorethylene, tetrachlorethylene and chlorobenzene; Aromatic hydrocarbons such as benzene, toluene, xylene, methoxybenzene, and 1,2-dimethoxybenzene; Alcohols such as methanol, ethanol, propanol, isopropanol, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, and cyclopentanone; Cellosolve such as methyl cellosolve, ethyl cellosolve, and butyl cellosolve; And ethers such as diethylene glycol dimethyl ether (DEGDME) and dipropylene glycol dimethyl ether (DPGDME). The content of the solvent is not particularly limited and may be suitably selected in consideration of coating efficiency, drying efficiency, and the like.

The composition for forming a liquid crystal film may further include an initiator. The initiator may serve to polymerize or crosslink the liquid crystal compound.

Examples of the initiator include photoinitiators such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin n-butyl ether, benzoin isobutyl ether, acetophenone, dimethyl anilino Acetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2,2-diethoxy-2-phenylacetophenone, 2-hydroxy- Methyl-1- [4- (methylthio) phenyl] -2-morpholino-propan-1-one, 4- (2-hydroxyethoxy) phenyl- 2- 2-ethyl anthraquinone, 2-t-butyl anthraquinone, 2-ethylhexanoic acid, 2-ethylhexanoic acid, Thioxanthone, 2-ethylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, 2,4-diethylthioxanthone, benzyldimethylketal, acetophenone Dimethyl ketal, p-dimethylamino Benzyl ester, oligo [2-hydroxy-2-methyl-1- [4- (1-methylvinyl) phenyl] propanone] and 2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide And one or more of the photoinitiators may be appropriately selected and contained in the composition in a predetermined ratio.

In one example, the initiator may be included in the composition in a ratio of from 0.1 parts by weight to 10 parts by weight based on 100 parts by weight of the liquid crystal compound. By controlling the content of the initiator as described above, effective polymerization and crosslinking of the liquid crystal can be induced, and deterioration of properties due to the residual initiator after polymerization and crosslinking can be prevented.

The method of curing the coated composition for forming a liquid crystal film is also known. For example, the curing method may include irradiating with appropriate heat and / or light to enable the coating solution to be filmed.

As described above, when a liquid crystal film is formed on the polarizing element using the above-described composition, the desired haze characteristics can be imparted to the polarizing plate.

When the protective film is formed on the polarizing element, the liquid crystal film may be formed on the protective film, and the method of forming the liquid crystal film is the same as the method of forming the liquid crystal film on the polarizing element described above.

The present application also relates to the use of a polarizing plate, for example an optical element comprising a polarizing plate.

In one example, the optical element includes a polarizing plate and a phase delay layer formed on one surface of the polarizing plate. The phase delay layer may be, for example, a 1/4 wavelength plate.

As the? / 4 wavelength layer, for example, a polymer film or a liquid crystal film can be used, and it can be a single layer or a multilayer structure. Alternatively, the? / 4 wavelength layer may be a liquid crystal layer. In one example, the liquid crystal layer as the? / 4 wavelength layer is formed on the surface of the substrate, and an alignment film may be present between the substrate and the liquid crystal layer.

The present application also relates to a display device including an optical element. The display device may be, for example, a liquid crystal display (LCD).

In one example, the LCD may further include a liquid crystal panel and a light source disposed on one side of the liquid crystal panel, and the optical element may be disposed between the liquid crystal panel and the light source. Further, the optical element may be arranged such that the polarizing plate is located closer to the light source than the? / 4 wavelength layer.

Other known configurations other than the configuration of the LCD described above can be included in the display device according to the present application without limitation.

Hereinafter, the present application will be described in more detail with reference to examples, but it should be apparent to those skilled in the art that the following examples do not limit the technical idea of the present application.

The physical properties of the liquid crystal film were measured in the following manner.

One. Hayes Measure

The haze of the liquid crystal films according to Examples and Comparative Examples was measured using a haze meter (NDH-5000SP) at a wavelength of 550 nm by the ASTM method.

< Example 1> - Preparation of liquid crystal film

A liquid crystal mixture was prepared in the same ratios as in Table 1 below.

Liquid crystal mixture content( % ) (3) 32.7 Formula 4 18.7 6 21.5 Formula 7 21.5 Initiator (Igacure 907) 5.6

The liquid crystal mixture was poured into toluene (toluene) solution so that the solid content became 25 wt%, and then heated at 50 DEG C for 1 hour to prepare a polymerizable liquid crystal mixture solution.

Fluorad (trade name: Fluorad, 3M) FC4430, which is a fluorocarbon surfactant, was added to the solution so as to be 2 wt% (8 wt% based on the total solids content of the liquid crystal mixture) relative to 100 wt% of the whole solution to form a liquid crystal film Lt; / RTI >

The composition was coated on a norbornene derivative film (Zeonor, Zeon) film surface-treated using a corona apparatus and cured to form a liquid crystal film. As shown in FIG. 6, the liquid crystal film can form a structure in which a liquid crystal compound is aggregated by a surfactant to have irregularities on its surface. The haze of the liquid crystal film was measured by ASTM method at a wavelength of 550 nm using a haze meter (NDH-5000SP). As a result, it was confirmed that the liquid crystal film had a haze value of about 35%.

< Comparative Example 1>

Except that a liquid crystal film was formed using a composition for forming a liquid crystal film in which the surfactant was added so as to be 0.2 wt% (0.8 wt% with respect to the total solid content of the liquid crystal mixture) relative to 100 wt% of the whole solution. To form a liquid crystal film. The evaluation of the haze of the liquid crystal film according to Comparative Example 1 showed a haze of about 1.5%, and it was confirmed that the desired haze characteristics could not be realized.

100: polarizing element
101: stretched layer of polyvinyl alcohol (PVA)
102: triacetyl cellulose (TAC) layer
103: cholesteric liquid crystal layer
104: 1/4 wavelength plate
200: liquid crystal film
201: unevenness
300: protective film

Claims

A polarizing element; And
And a liquid crystal film disposed on the polarizing element and including a liquid crystal compound and a surfactant and having a haze within a range of 5% to 50%.

The method according to claim 1,
The polarizing element is an absorption type polarizing element or a reflection type polarizing element.

3. The method of claim 2,
Wherein the absorption type polarizing element comprises a stretched layer of polyvinyl alcohol (PVA) in which a dye is dyed.

3. The method of claim 2,
The reflection type polarizing element includes a laminate including a cholesteric liquid crystal layer; A mammary liquid crystal layer; A wire grid polarizing layer; And DBEF (Dual Brightness Enhancement Film).

5. The method of claim 4,
Wherein the cholesteric liquid crystal layer comprises a cholesteric liquid crystal region and the spiral axis of the cholesteric liquid crystal molecules in the liquid crystal region is perpendicular to the polarizer.

The method according to claim 1,
Wherein the liquid crystal compound is vertically aligned.

The method according to claim 1,
Wherein the liquid crystal compound is a polymer of reactive mesogens.

8. The method of claim 7,
The reactive mesogen is a polarizing plate represented by the following formula (1): < EMI ID =
[Chemical Formula 1]

Wherein A is a single bond, -COO- or -OCO-, and R ₁ to R ₁₀ are each independently selected from the group consisting of hydrogen, a halogen, an alkyl group, an alkoxy group, a cyano group, a nitro group, -OQP, Wherein at least one of R ₁ to R ₁₀ is -OQP or a substituent of the following formula 2, Q is an alkylene group or an alkylidene group, P is an alkenyl group, an epoxy group, a cyano group, a carboxyl group, an acryloyl group, A methacryloyl group, an acryloyloxy group or a methacryloyloxy group;
(2)

In the formula 2 B is a single bond, -COO- or -OCO-, R ₁₁ to R ₁₅ are each independently hydrogen, halogen, an alkyl group, an alkoxy group, a cyano group, a nitro group or -OQP provided that, R ₁₁ to At least one of R < ₁₅ > is -OQP, Q is an alkylene group or an alkylidene group, and P is an alkenyl group, an epoxy group, a cyano group, a carboxyl group, an acryloyl group, a methacryloyl group, Methacryloyloxy group.

The method according to claim 1,
Wherein the liquid crystal compound in the liquid crystal film is aggregated by a surfactant.

The method according to claim 1,
Wherein the liquid crystal film comprises 5 to 20 parts by weight of a surfactant based on 100 parts by weight of the liquid crystal compound.

The method according to claim 1,
Wherein the liquid crystal film has a center line average roughness (Ra) in the range of 100 nm to 10,000 nm.

The method according to claim 1,
Wherein the polarizing plate further comprises a protective film, and the liquid crystal film is formed on the protective film.

And forming a liquid crystal film having a haze within a range of 5% to 50% by using a composition for forming a liquid crystal film containing a liquid crystal compound and a surfactant on the polarizing element.

14. The method of claim 13,
Wherein the composition for forming a liquid crystal film comprises 100 parts by weight of a liquid crystal compound and 5 to 20 parts by weight of a surfactant.

An optical element comprising the polarizing plate of claim 1.