KR20160120485A

KR20160120485A - Vertical alignment layer and liquid crystal device comprising the same

Info

Publication number: KR20160120485A
Application number: KR1020150049576A
Authority: KR
Inventors: 김진홍; 오동현; 민성준; 유정선; 김정운; 임은정; 김연희; 강연주
Original assignee: 주식회사 엘지화학
Priority date: 2015-04-08
Filing date: 2015-04-08
Publication date: 2016-10-18
Also published as: KR101987371B1

Abstract

The present invention relates to a vertical alignment film, a liquid crystal element comprising the same, a manufacturing method thereof, and a light modulation device including the vertical alignment film. The vertical alignment film can effectively induce vertical alignment of liquid crystals and realize a general transmission mode by being applied to the liquid crystal element. The vertical alignment film can be applied to a variety of light modulation devices such as a smart window, a window protection film, a flexible display element, an active retarder for displaying a 3D image, a viewing angle adjusting film, or the like.

Description

TECHNICAL FIELD [0001] The present invention relates to a vertical alignment film and a liquid crystal device including the vertical alignment film,

The present invention relates to a vertical alignment film, a liquid crystal device including the same, a method of manufacturing the same, and a light modulation device including the vertical alignment film.

An LCD (Liquid Crystal Display) realizes an image by orienting a liquid crystal compound in a certain direction and switching the orientation through application of a voltage. An alignment film for aligning the liquid crystal molecules of the liquid crystal layer is formed inside the display panel. Generally, when a voltage is not applied to an electric field generating electrode, liquid crystal molecules are arranged in a certain direction by an orientation film. When a voltage is applied to an electric field generating electrode, liquid crystal molecules rotate according to the direction of an electric field.

The present application provides a vertical alignment film, a liquid crystal device and a light modulation device, which can effectively induce vertical alignment of a liquid crystal and can be applied to a liquid crystal device to realize a normal transmission mode.

This application relates to a vertical alignment film. Exemplary vertical alignment films can be applied to a light modulation device. In one example, the vertical alignment film may satisfy the following general formula (1).

[Formula 1]

0 ≤ | Y - {1 × 10 ^-4 X ³ + 1.2 × 10 ^-3 X ² ^{- 3.1 × 10 -3 X + 1.6} × 10 -3} | 0.04

In the general formula 1, X represents the AFM Z-scale surface roughness of the vertical alignment film, and Y represents the surface polarity of the vertical alignment film. On the other hand, the surface energy of the vertical alignment film (γ ^surface) is considered non-polar molecules in the dispersion forces and the polar inter-molecular interaction forces (γ ^surface = γ ^dispersion + γ ^polar) may be calculated and this application is the surface energy γ ^surface The ratio of the polar term (gamma ^polar ) to the polarity of the surface can be defined. The vertical alignment film according to the present application can be vertically aligned in a state where an external alignment force is not applied by being applied to a liquid crystal device or the like by taking into consideration the mutual relationship of surface roughness and polarity as described above. That is, when the vertical alignment film is applied to a liquid crystal device or the like, the normal transmissive mode can be effectively realized because the surface roughness and the polarity degree of the vertical alignment film satisfy the above-mentioned general formula (1). In one example, the graph Y = 1 x 10 ^-4 X ³ + 1.2 x 10 ^-3 X ² - 3.1 x 10 < ^-3 > X + 1.6 x 10 < ^-3 > On the other hand, if | Y - {1 × 10 ^-4 X ³ + 1.2 × 10 ^-3 X ² - 3.1 x 10 ^-3 X + 1.6 x 10 ^-3 } may be 0 to 0.04 or 0 to 0.03, 0 to 0.02, 0 to 0.01 or 0 to 0.008 as described above. As shown in the graph of Fig. 3, Y = 1 x 10 ^-4 X ³ + 1.2 x 10 ^-3 x ² - may be an R ² (coefficient of determination) is 0.9997 eseo ^{3 - 3.1 × 10 -3 X +} 1.6 × 10.

The surface orientation of the vertical alignment film of the present application is not particularly limited as long as the above general formula 1 is satisfied. That is, the surface energy, the surface polarity, and the surface roughness of the vertical alignment film are not particularly limited as long as the above general formula 1 is satisfied.

In one example, the surface energy of the vertical alignment layer may be 5 mN / m to 100 mN / m, 8 mN / m to 80 mN / m, or 10 mN / m to 50 mN / m. In addition, the polarity of the vertical alignment film of the present application may be in the range of 0 to 0.5 or 0 to 0.4. In the range of the surface energy or the degree of polarity, the vertical alignment film can effectively induce the vertical alignment of the liquid crystal and the like. As described above, the surface energy (? ^Surface , mN / m) can be calculated as? ^Surface =? ^Dispersion +? ^Polar . The surface energy may be a value measured by a known measuring method. In one example, the surface energy can be measured using a Drop Shape Analyzer (DSA100 from KRUSS). For example, the surface energy of a target sample to be measured is diluted with about 2% by weight of solid content in flourobenzene to a thickness of about 50 nm and a coating area of 4 cm ² (width: 2 cm, length: : 2 cm) at room temperature for about 1 hour and then thermal annealed at 160 ° C for about 1 hour. The process of dropping the deionized water whose surface tension is known in the film subjected to thermal aging and obtaining the contact angle is repeated 5 times to obtain an average value of the obtained five contact angle values and similarly, The process of dropping the known diiodomethane and determining the contact angle thereof is repeated five times, and an average value of the obtained five contact angle values is obtained. Thereafter, the surface energy can be obtained by substituting the value (Strom value) of the surface tension of the solvent by the Owens-Wendt-Rabel-Kaelble method using the average value of the contact angle with the deionized water and diiodo methane obtained.

In another example, the vertical alignment film may have an AFM Z-scale surface roughness of 0.1 nm to 50 nm, 0.2 nm to 30 nm, 0.3 nm to 10 nm, or 0.4 nm to 8 nm. In the surface roughness range, the vertical alignment film can effectively realize the vertical alignment of the liquid crystal. The surface roughness may be a value measured by a known average surface roughness measuring method, for example, a value measured using a Multimode AFM instrument manufactured by Bruker.

In order to set the surface energy or the average surface roughness of the vertical alignment film within the above-mentioned range, a known method of controlling surface energy or surface roughness can be selected and used without limitation. For example, it is possible to select a material capable of exhibiting the above-described surface characteristics as a material of the vertical alignment film, or to add a further additive capable of exhibiting surface characteristics to the material of the vertical alignment film, Control.

In one example, the vertical alignment film may comprise a vertically oriented polymer. The material of the vertically oriented polymer is not particularly limited as long as it satisfies the above-mentioned physical properties.

In one example, the vertical orientation film polymer may have a solids content in the range of 0.5 wt% to 4.5 wt%, 1 wt% to 4 wt%, 1.5 wt% to 3.5 wt%, or 1.8 wt% to 3.2 wt% . Within this range, the present application can realize a functional relationship between the above-described AFM Z-scale surface roughness of the vertical alignment film and the surface polarity of the vertical alignment film. In the present specification, the solid content refers to a solid content at the time when the polymer is prepared in the form of a coating liquid or the like and is applied to a vertical alignment film production process.

In one example, the vertical alignment layer according to the present application may be formed of a polymer selected from the group consisting of polymethyl methacrylate, acrylic acid / methacrylic acid copolymer, styrene / maleic anhydride copolymer, polyvinyl alcohol, denatured polyvinyl alcohol, Acrylamide), styrene / vinyltoluene copolymer, chlorosulfonated polyethylene, nitrocellulose, polyvinyl chloride, chlorinated polyolefin, polyester, polyimide, vinyl acetate / vinyl chloride copolymer, ethylene / vinyl acetate copolymer, carboxymethyl But are not limited to, cellulose, polyethylene, polypropylene or polycarbonate.

In addition, in one example, the vertically oriented polymer may include, but is not limited to, polymerized units derived from a compound of formula (1).

[Chemical Formula 1]

Wherein L is a single bond or an alkylene group, and R ₁ to R ₁₀ are each independently selected from the group consisting of hydrogen, halogen, an alkyl group, an alkoxy group, group, an alkoxycarbonyl group, a cyano group, a nitro group, a -P, being chihwangiyi of -OQP or the following general formula 2, R ₁ to R ₁₀ is at least one of -P, or a substituent of the formula -OQP or 2, R ₁ to Two adjacent substituents of R ₅ or two adjacent substituents of R ₆ to R ₁₀ are connected to each other to form a benzene substituted with -OQP wherein Q is an alkylene group or an alkylidene group, A methacryloyl group, an acryloyloxy group, or a methacryloyloxy group, which is a polymerizable functional group, such as a vinyl group, an epoxy group, a cyano group, a carboxyl group, an acryloyl group,

(2)

Wherein B is a single bond, -COO- or -OCO-, and R ₁₁ to R ₁₅ are each independently selected from the group consisting of hydrogen, a halogen, an alkyl group, an alkoxy group, an alkoxycarbonyl group, a cyano group, a nitro group, -OQP, at least one of R ₁₁ to R ₁₅ is -P or -OQP, or two adjacent substituents of R ₁₁ to R ₁₅ are connected to each other to form benzene substituted with -OQP, wherein Q is alkyl And P is a polymerizable functional group such as 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.

The formation of benzene substituted with -OQP in the above two substituents in Formulas 1 and 2 means that two adjacent substituents are connected to each other to form a naphthalene skeleton substituted with -OQP as a whole have.

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

The term " single bond " in the above formulas (1) and (2) means a case where no separate atom exists in the portion represented by L, 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.

This application is, in the case of Formula 1 and 2, R ₁ to R _15, if at least one of the -P or -OQP of, it is possible to except where R ₁ to R ₁₅ is a halogen atom, substituted by halogen As the functional group, for example, an alkyl group substituted with a halogen, an alkenyl group substituted with a halogen, an alkynyl group substituted with a halogen, or an alkoxy group substituted with a halogen may be excluded. Examples of the halogen include chlorine, bromine, iodine, and the like. When at least one of R ₁ to R ₁₅ is -P, it may mean that R ₁ to R ₁₅ are not -OQP or Formula 2, and when P is alkenyl or alkenyl, epoxy, A cyano group, a carboxyl group, an acryloyl group, a methacryloyl group, an acryloyloxy group or a methacryloyloxy group.

In addition, the vertically oriented polymer may include, but is not limited to, a polymerized unit derived from a compound represented by the following formula (3).

(3)

In Formula 3, R ₂₀ may represent hydrogen, an alkyl group, an alkenyl group, an alkynyl group, or an aryl group.

The term "alkyl group" as used herein means an alkyl group having 1 to 30 carbon atoms, 1 to 25 carbon atoms, 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 &Lt; / RTI > The alkyl group may have a linear, branched or cyclic structure and may optionally be substituted with one or more substituents. However, the case where the halogen element is substituted may be excluded.

Unless otherwise specified, the "alkenyl group" in the present specification may mean 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.

In the present specification, "alkynyl", unless otherwise specified, may mean an alkynyl 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 alkynyl group may be linear, branched or cyclic. In addition, the alkynyl group may be optionally substituted with one or more substituents.

The term "alkoxy group" as used herein may mean 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, unless otherwise specified. The alkoxy group may be linear, branched or cyclic. In addition, the alkoxy group may be optionally substituted with one or more substituents.

Unless otherwise specified, the term "alkylene group" or "alkylidene group" as used herein may mean 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. Also, the alkylene group or alkylidene group may be optionally substituted with one or more substituents.

As used herein, the term " aryl group " means a monovalent residue derived from a compound or a derivative thereof containing a structure containing benzene or two or more benzenes condensed or bonded, unless otherwise specified have. The aryl group may be, for example, an aryl group having 6 to 22 carbon atoms, preferably 6 to 16 carbon atoms, and more preferably 6 to 13 carbon atoms, and examples thereof include a phenyl group, a phenylethyl group, a phenylpropyl group, , A tolyl group, a xylyl group or a naphthyl group.

Examples of the substituent which may be substituted in the specific functional group in the present invention include alkyl groups, alkoxy groups, alkenyl groups, epoxy groups, oxo groups, oxetanyl groups, thiol groups, cyano groups, carboxyl groups, acryloyl groups, methacryloyl groups, Acryloyloxy group, methacryloyloxy group, aryl group, and the like, but the present invention is not limited thereto.

The -P, -OQP or the moiety of Formula 2, which may be present in at least one of the above Formulas 1 and 2, may be present, for example, at the position of R ₃ , R ₈ or R ₁₃ . It is also preferred that R < ₃ > and R < _{4 &} gt ;, or R < ₁₂ > and R < ₁₃ > The substituent other than -P, -OQP or the residue of the formula (4) in the compound of the formula (1) or the residue of the formula (2), or a substituent other than the benzene which is connected to each other, may be, for example, hydrogen, halogen, An alkoxycarbonyl group having a straight or branched chain alkoxy group having 1 to 8 carbon atoms, a cycloalkyl group having 4 to 12 carbon atoms, a cyano group, an alkoxy group having 1 to 8 carbon atoms, a cyano group, or a nitro group Preferably a straight chain or branched alkyl group having 1 to 8 carbon atoms, a cycloalkyl group having 4 to 12 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, an alkoxy group having 1 to 8 carbon atoms, a linear or branched alkoxy group having 1 to 8 carbon atoms A carbonyl group or a cyano group.

The present application also relates to a liquid crystal device including the aforementioned vertical alignment film. The liquid crystal device may include a vertical alignment layer and a liquid crystal layer present on the vertical alignment layer and including a liquid crystal compound. The vertical alignment layer can induce the vertical alignment of the liquid crystal compound of the liquid crystal device. The liquid crystal device according to the present application can realize a normal transmission mode in a state in which no external directing force is applied.

In the liquid crystal layer, the liquid crystal compound may exist in an initial state, for example, in a state in which the external directing force is not applied, in one direction, and this alignment direction may be changed by external action, for example, Can be changed. Accordingly, in the present application, a device capable of switching between a white mode and a black mode can be implemented. For example, the present application may implement a device in a normally transparent mode. In one example, the haze of the device of the present application in the transmission mode may be 10% or less, 8% or less, 6% or less, or 5% or less. Also, the black mode in the present application may exhibit a haze of, for example, 60% or more, 70% or more, 80% or more, or 90% or more. The haze may be a percentage of the transmittance of the diffused light to the transmittance of the total transmitted light passing through the object to be measured. The haze can be evaluated using a hazemeter (NDH-5000SP). The haze can be evaluated in the following manner using the haze meter. That is, light is transmitted through the object to be measured and is incident into the integrating sphere. In this process, light is separated into diffused light (DT) and parallel light (PT) by the object to be measured. The light is reflected in the integrating sphere and condensed on the light receiving element, and the haze can be measured through the condensed light Do. That is, the total transmitted light TT according to the above procedure is the sum (DT + PT) of the diffused light DT and the parallel light PT and the haze is the percentage of diffused light with respect to the total transmitted light (Haze (%) = 100 X DT / TT). Further, the liquid crystal device of the present application can exhibit excellent transparency in the transmission mode. For example, the liquid crystal element is in a normal orientation state, that is, in a normal orientation state, that is, in a state in which no external action is exerted, such as a state in which no external orientation force is applied, at least 80%, at least 85%, at least 90% Light transmittance can be shown. The light transmittance may be a light transmittance for a wavelength in a visible light region, for example, in a range of about 400 nm to 700 nm. The light transmittance may mean a light transmittance in the case where the liquid crystal layer does not include a dye described later. For example, when the liquid crystal layer further comprises 1% by weight of a colorant, the light transmittance is 60% 70% or more, or 80% or more.

In the present application, the external orientation force may mean any kind of action that may affect the liquid crystal orientation, for example, voltage. That is, the state in which the external directing force is not applied may mean a state in which the voltage is not applied.

Fig. 1 shows a structure of an exemplary element, which includes a liquid crystal layer 11 and a vertical alignment film 12 formed on at least one side of the liquid crystal layer, and the liquid crystal layer 11 is an example of a liquid crystal device including a polymer and a liquid crystal region gouge. In the present application, the liquid crystal region means a region in which a liquid crystal compound is present in the polymer, and may be, for example, a region containing a liquid crystal compound and being dispersed in the polymer in a phase-separated state from the polymer .

As the liquid crystal compound, any kind of compound can be used as long as it is phase-separated in the polymer and can exist in the state oriented by the polymer. For example, as the liquid crystal compound, a smectic liquid crystal compound, a nematic liquid crystal compound, or a cholesteric liquid crystal compound can be used. The liquid crystal compound may be in a form that is phase-separated and not bonded to the polymer, and the orientation can be changed accordingly when a voltage is applied from the outside. For this purpose, for example, the liquid crystal compound may be a compound having no polymerizable group or a crosslinkable group.

The liquid crystal device may include a polarizing layer disposed on one side or both sides of the liquid crystal layer. Examples of the polarizing layer include, but are not limited to, ordinary materials used in conventional LCDs such as a polarizing plate such as a PVA (poly (vinyl alcohol)), a liquid crystal (LLC: Lyotropic Liquid Cystal) A polarizing layer implemented by a coating method such as a polarizing coating layer including a mesogen and a dichroic dye can be used. The arrangement of the light absorption axis of the polarizing layer in the presence of the polarizing layer is not particularly limited and may be selected in consideration of the initial orientation of the liquid crystal layer and the mode of the device to be implemented. The term " initial orientation of the liquid crystal layer " in the present application may mean an optical axis of the liquid crystal layer, for example, a slow axis in a state in which no voltage is applied.

The liquid crystal element may include one or two or more substrate layers. Typically, a liquid crystal layer may be disposed between two oppositely disposed substrate layers. When the base layer is present, the above-mentioned polarizing layer may usually exist outside the base layer, but if necessary, the polarizing layer may be present inside the base layer, that is, between the liquid crystal layer and the base layer. In this case, the use of the above-mentioned polarizing coating layer may be advantageous as the polarizing layer.

As the substrate layer, known materials can be used without any particular limitation. For example, inorganic films such as glass films, crystalline or amorphous silicon films, quartz or indium tin oxide (ITO) films, and plastic films can be used. As the base layer, an optically isotropic base layer, a optically anisotropic base layer such as a retardation layer, a polarizing plate, a color filter substrate, or the like can be used. For example, when the polarizing layer is present inside the base layer, that is, between the liquid crystal layer and the base layer, a device of suitable performance can be realized even when an anisotropic base layer is used as the base layer.

Examples of the plastic substrate layer include TAC (triacetyl cellulose); A cycloolefin copolymer (COP) such as a norbornene derivative; Poly (methyl methacrylate), PC (polycarbonate), polyethylene (PE), polypropylene (PVP), polyvinyl alcohol (PVA), diacetyl cellulose (DAC), polyacrylate (PAC), polyether sulfone (PES) (PPS), polyarylate (PAR), amorphous fluororesin, or the like may be used as the base layer, but it is possible to use a base layer containing at least one selected from the group consisting of PPS (polyphenylsulfone), PEI (polyetherimide), PEN (polyethylenemaphthatate) A coating layer of a silicon compound such as gold, silver, silicon dioxide or silicon monoxide, or a coating layer such as an antireflection layer may be present on the base layer.

An electrode layer may be included on the surface of the base layer, for example, on the surface of the base layer on the side of the liquid crystal layer (for example, the surface of the base layer in contact with the liquid crystal layer). The electrode layer can be formed by, for example, depositing a conductive polymer, a conductive metal, a conductive nanowire, or a metal oxide such as ITO (Indium Tin Oxide). The electrode layer may be formed to have transparency. In this field, various materials and forming methods capable of forming a transparent electrode layer are known, and all of these methods can be applied. If necessary, the electrode layer formed on the surface of the base layer may be appropriately patterned. In this case, the above-mentioned vertical alignment film may be formed on the surface of the base layer or on the surface of the electrode layer formed on the base layer.

The present application also relates to a method of manufacturing the aforementioned vertical alignment film. The manufacturing method may include applying a coating liquid containing a vertically oriented polymer to the substrate layer. The alignment film of the present application may be an alignment film formation material. In one example, a coating liquid containing polyvinyl alcohol may be applied on a transparent support, followed by heating and drying to form a vertically oriented polymer layer, and the polymer layer may be subjected to orientation treatment such as rubbing treatment. Examples of the application method include a spin coating method, a dip coating method, an extrusion coating method and a bar coating method. In consideration of the surface characteristics of the above-mentioned vertical alignment film, dip coating method, extrusion coating method and bar coating method Or a coating using a Mayer bar may be used. The film thickness may be 0.1 탆 or more, less than 1 탆, 0.1 to 0.95 탆, 0.2 to 0.9 탆, 0.3 탆 to 0.85 탆, 0.4 탆 to 0.85 탆 or 0.5 탆 to 0.83 탆, but is not limited thereto. Within this thickness range, the present application can realize the functional relationship between the above-described AFM Z-scale surface roughness of the vertical alignment film and the surface polarity of the vertical alignment film. The heating and drying can be carried out at 70 to 250 캜, 80 to 240 캜 or 90 to 230 캜. The drying time may be from 1 minute to 60 minutes, from 1 minute to 40 minutes, or from 1 minute to 35 minutes. By controlling the drying temperature and the drying time in the above range, the present application can realize the desired surface characteristics of the vertical alignment film.

As the vertical alignment film, a polymer layer can be used as described above, and a treatment method widely used as a liquid crystal alignment treatment process of an LCD can be used, and orientation treatment such as rubbing treatment can be used. The alignment film may be positioned so as to define the alignment direction of the liquid crystal compound such as a liquid crystalline discotic compound provided thereon. In the rubbing treatment, the surface of the polymer layer can generally be treated in a predetermined direction using fibers such as polyamide or polyester.

The present application also relates to a method of manufacturing a liquid crystal device. The manufacturing method of a liquid crystal device may include forming a liquid crystal layer containing a liquid crystal compound on the above-mentioned vertical alignment film. The liquid crystal layer containing the liquid crystal compound can be formed by coating with a conventional coating method such as bar coating, comma coating, ink jet coating or spin coating.

In one example, the liquid crystal layer may be laminated and then irradiated with appropriate energy capable of inducing crosslinking or polymerization, for example, light. The crosslinking or polymerization may mean crosslinking or polymerization between the crosslinkable or polymerizable compounds contained in the liquid crystal layer. As a result, the polymer in the liquid crystal layer can be completely cured.

The present application also relates to a light modulation device including the vertical alignment film or the liquid crystal device. Examples of the optical modulating device include, but are not limited to, a smart window, a window protective film, a flexible display device, an active retarder for 3D image display, or a viewing angle adjusting film. The manner of constructing the optical modulator as described above is not particularly limited, and a conventional method can be applied as long as the vertical alignment film is used.

The vertical alignment film of the present application is applied to a liquid crystal device or the like to effectively induce the vertical alignment of the liquid crystal and to realize the transmissive mode in a state in which the external alignment is unexcited. Such a vertical alignment layer can be applied to various optical modulation devices such as a smart window, a window protective film, a flexible display device, an active retarder for 3D image display, or a viewing angle adjusting film.

1 shows a cross-sectional view of an exemplary liquid crystal device.
2 is a graph showing light transmittance according to incident angles of vertical alignment layers according to Examples and Comparative Examples.
3 is a graph showing the surface polarity according to the surface roughness of the vertical alignment film according to Examples and Comparative Examples.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. However, the scope of the present application is not limited by the following description.

Example One

A vertical alignment layer polymer solution was prepared by dissolving a vertical alignment layer polymer having a repeating unit represented by the following formula (A) (Mw = about 55,000 in the following formula A) in toluene so that the polymer solid content was 2% by weight. Thereafter, the solution was coated on a PET (polyethylene terephthalate) film (substrate layer) having a transparent electrode formed thereon to a thickness of about 800 nm using a mayer bar, and then heat-treated at 100 ° C for 2 minutes to form a vertical alignment film .

(A)

Example 2

A vertical alignment film was formed in the same manner as in Example 1 except that a vertical alignment film polymer having a repeating unit represented by the following formula (B) (Mw = about 50,000 in the following formula (B)) was used.

[Chemical Formula B]

Example 3

A vertical alignment film was formed in the same manner as in Example 1 except that a vertical alignment film polymer having a repeating unit represented by the following formula (C) (Mw = about 53,000 in the following formula (C)) was used.

&Lt; RTI ID = 0.0 &

Example 4

Except that a vertical alignment film polymer (Mw = about 50,000, m: n = 4: 6) having a repeating unit represented by the above formula (C) and a repeating unit represented by the following formula (C ') was used. .

[Chemical formula C ']

Example 5

A vertical alignment film was formed in the same manner as in Example 1, except that a vertical alignment film polymer having a repeating unit represented by the following formula (D) (Mw = about 70,000 in the following formula (D)) was used and heat treatment was performed at 200 ° C for 30 minutes.

[Chemical Formula D]

Example 6

A vertical alignment film polymer solution was prepared by dissolving RMM 28B of MERCK as a vertical alignment film polymer in toluene so that the polymer solid content was 2% by weight. Thereafter, the solution was coated on a PET (polyethylene terephthalate) film (substrate layer) having a transparent electrode formed thereon to a thickness of about 800 nm using a mayer bar, heat-treated at 100 ° C for 2 minutes, .

Comparative Example One

A vertical alignment film was formed in the same manner as in Example 1, except that a vertical alignment film polymer having a repeating unit represented by the following formula (E) (Mw = 70,000 in the following formula E) was used and heat treatment was performed at 100 ° C for 2 minutes.

(E)

Comparative Example 2

The vertical alignment film was formed in the same manner as in Example 6, except that the polymer was dissolved so that the solid content was 5% by weight.

Comparative Example 3

A vertical alignment film was formed in the same manner as in Example 6, except that the polymer solid content was 10% by weight.

Comparative Example 4

A vertical alignment film was formed in the same manner as in Example 6, except that the coating was performed using spin coating.

Comparative Example 5

A vertical alignment layer polymer solution was prepared by dissolving a silicone and acrylate based adhesive (Dow Corning 7652) in toluene to a polymer solids content of 5% by weight. Then, the solution was coated on a PET (polyethylene terephthalate) film (substrate layer) having a transparent electrode formed thereon to a thickness of about 1 탆 using a mayer bar, and then heat-treated at 100 캜 for 5 minutes to form a vertical alignment film .

Experimental Example 1 - vertical orientation characteristic

A liquid crystal layer was formed on one side of the vertical alignment film prepared in Examples and Comparative Examples. Specifically, a liquid crystal composition comprising a liquid crystal compound (negative LC of HCCH and 1 wt% of dye) as a liquid crystal composition, a proper amount of a photoinitiator and a toluene solvent was prepared. Subsequently, the liquid crystal composition was applied to the vertical alignment film to form a coated layer. Thereafter, the coated layer was dried at room temperature for about 2 minutes. Subsequently, the liquid crystal composition was aligned at room temperature according to the orientation of the vertical alignment film at the bottom, and then irradiated with ultraviolet light (about 100 mW / cm ² ) for about 10 seconds to form a liquid crystal layer.

When the liquid crystal and dye in the liquid crystal layer are aligned in the vertical direction, the light transmittance depends on the incident light. That is, as the transmittance at the front of the vertically aligned liquid crystal cell is highest and the incident angle is increased, the transmittance is significantly reduced.

In contrast, when the liquid crystal and dye are oriented randomly on the surface, the difference in transmittance according to the incident angle is not large.

Therefore, the light transmittance of the liquid crystal film cell according to the angle of incidence (viewing angle) was measured (halogen lamp, LCMS-200) to judge whether the liquid crystal was vertically aligned or not and the light transmittance according to the incident angle was shown in FIG.

On the other hand, when the liquid crystal film cell is observed at the front (incident angle of 0), it can be determined that the vertical alignment is formed when the light transmittance is 58% or more (dye 1 wt%).

Experimental Example 2 - Contact angle , Surface energy and Polarity Measure

In this application, the contact angle and surface energy were measured using a Drop Shape Analyzer (product of DSU100, KRUSS).

The surface energy was measured by dropping the deionized water whose surface tension was known in the vertical alignment films according to the examples and comparative examples to be measured and measuring the contact angle thereof five times. The average value of the five contact angle values The same procedure as that of dropping the diiodomethane having a known surface tension and determining the contact angle thereof is repeated five times to obtain an average value of the obtained five contact angle values. Then, the surface energy was obtained by substituting the value (Strom value) of the surface tension of the solvent by the Owens-Wendt-Rabel-Kaelble method using the average value of the contact angle with the deionized water and diiodo methane obtained.

The surface energy of the vertical alignment film (γ ^surface) is considered non-polar molecules in the dispersion forces and the polar inter-molecular interaction forces (γ ^surface = γ ^dispersion + γ ^polar) may be calculated, polar term (γ in the surface energy γ ^surface the ratio of the ^polar) can be defined as the polarity (polarity) of the surface.

Experimental Example 3 - Measurement of surface roughness

The AFM Z-scale surface roughness (arithmetic mean roughness, Ra) of the vertical alignment layers according to Examples and Comparative Examples was measured using a Multimode AFM instrument manufactured by Bruker.

FIG. 3 is a graph showing a functional relationship of surface polarity according to surface roughness. The measurement conditions are as follows.

Measuring instrument

Multimode AFM (Bruker, multimode 8)

Measuring conditions

Parameters: Mode: ScanAsyst in air, Samples / line: 512x512, Scan rate: 0.7Hz)

AFM probe - Silicon tip on aluminum nitride w / Al coating (Bruker), Material: Silicon Nitride, Resonance Frequency: 50 ~ 90 kHz, Force Constant: 0.4 N / m, Thickness: 0.65㎛, Length: 115 ± 10㎛, Width : 25 탆, Tip height: 5 탆

Software - Nanoscope 8.15

Vertical alignment property Contact angle (°) Surface energy mN / m) Polarity Surface roughness H ₂ O MI gamma ^표면 gamma ^dispersion gamma ^polar Ra Example 1 Yes 97 23 46.7 46.7 0.00 0.0000 0.5 Example 2 Yes 94 13 49.6 49.6 0.03 0.0006 1.8 Example 3 Yes 96 18 48.3 48.3 0.00 0.0000 0.4 Example 4 Yes 93 18 48.6 48.6 0.07 0.0014 0.4 Example 5 Yes 91 41 40.1 39.2 0.90 0.0224 4.5 Example 6 Yes 90 59 31.8 29.4 2.40 0.0755 6.9 Comparative Example 1 No 88 55 34.1 31.5 2.60 0.0762 1.3 Comparative Example 2 No 90 49 36.7 35.1 1.60 0.0436 0.8 Comparative Example 3 No 108 85 15.8 14.8 1.00 0.0633 0.9 Comparative Example 4 No 85 60 32.5 28.4 4.10 0.1262 0.9 Comparative Example 5 No 115 105 8.5 6.9 1.60 0.1882 1.2

11: liquid crystal layer
12: vertical alignment film

Claims

A vertical alignment film satisfying the following general formula 1:
[Formula 1]
0 ≤ | Y - {1 × 10 ^-4 X ³ + 1.2 × 10 ^-3 X ² ^{- 3.1 × 10 -3 X + 1.6} × 10 -3} | 0.04
In the general formula 1, X represents the AFM Z-scale surface roughness of the vertical alignment film, and Y represents the surface polarity of the vertical alignment film.

The vertical alignment film according to claim 1, wherein the surface energy is in the range of 5 mN / m to 100 mN / m.

The vertical alignment film according to claim 1, wherein the AFM Z-scale surface roughness is in the range of 0.1 nm to 50 nm.

The vertical alignment film according to claim 1, wherein the surface polarity is in the range of 0 to 0.5.

The vertical alignment film according to claim 1, comprising a vertically oriented polymer.

6. The vertical alignment film of claim 5, wherein the vertically oriented polymer has a solids content in the range of 0.5 wt% to 4.5 wt%.

6. The composition of claim 5 wherein the vertically oriented polymer is selected from the group consisting of polymethyl methacrylate, acrylic acid / methacrylic acid copolymer, styrene / maleic anhydride copolymer, polyvinyl alcohol, denatured polyvinyl alcohol, poly (N-methylol acrylamide ), Styrene / vinyltoluene copolymer, chlorosulfonated polyethylene, nitrocellulose, polyvinyl chloride, chlorinated polyolefin, polyester, polyimide, vinyl acetate / vinyl chloride copolymer, ethylene / vinyl acetate copolymer, carboxymethylcellulose, A vertical alignment film comprising polyethylene, polypropylene or polycarbonate.

6. The vertical alignment film according to claim 5, wherein the vertically oriented polymer comprises a polymerized unit derived from the following formula:
[Chemical Formula 1]

Wherein L is a single bond or an alkylene group, and R ₁ to R ₁₀ are each independently selected from the group consisting of hydrogen, halogen, an alkyl group, an alkoxy group, group, an alkoxycarbonyl group, a cyano group, a nitro group, a -P, being chihwangiyi of -OQP or the following general formula 2, R ₁ to R ₁₀ is at least one of -P, or a substituent of the formula -OQP or 2, R ₁ to Two adjacent substituents of R ₅ or two adjacent substituents of R ₆ to R ₁₀ are connected to each other to form a benzene substituted with -OQP wherein Q is an alkylene group or an alkylidene group, An epoxy group, a cyano group, a carboxyl group, an acryloyl group, a methacryloyl group, an acryloyloxy group or a methacryloyloxy group:
(2)

Wherein B is a single bond, -COO- or -OCO-, and R ₁₁ to R ₁₅ are each independently selected from the group consisting of hydrogen, a halogen, an alkyl group, an alkoxy group, an alkoxycarbonyl group, a cyano group, a nitro group, -OQP, at least one of R ₁₁ to R ₁₅ is -P or -OQP, or two adjacent substituents of R ₁₁ to R ₁₅ are connected to each other to form benzene substituted with -OQP, wherein Q is alkyl And 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.

A vertical alignment film according to claim 1; And a liquid crystal layer present on the vertical alignment film and including a liquid crystal compound.

10. The liquid crystal device according to claim 9, wherein the haze is 10% or less in a state in which no external directing force is applied.

The liquid crystal device according to claim 9, wherein the liquid crystal compound comprises a smectic liquid crystal compound, a nematic liquid crystal compound or a cholesteric liquid crystal compound.

A method for manufacturing a vertical alignment film according to claim 1, which comprises applying a coating liquid containing a vertically oriented polymer.

The method of claim 12, comprising drying at a temperature of from 70 캜 to 250 캜 for 1 minute to 60 minutes.

A liquid crystal device manufacturing method comprising forming a liquid crystal layer containing a liquid crystal compound on a vertical alignment film according to claim 1.

A light modulation device comprising the vertical alignment film of claim 1.