KR20200057307A - Retardation film, manufacturing method of same, polarizing plate comprising same and liquid crystal display device comprising same - Google Patents

Abstract

The present application relates to a method of manufacturing a retardation film, a retardation film manufactured thereby, a polarizing plate comprising the same, and a liquid crystal display device including the same.

Description

Retardation film, manufacturing method thereof, polarizing plate including the same, and liquid crystal display device including the same {RETARDATION FILM, MANUFACTURING METHOD OF SAME, POLARIZING PLATE COMPRISING SAME AND LIQUID CRYSTAL DISPLAY DEVICE COMPRISING SAME}

The present invention relates to a retardation film, a manufacturing method thereof, a polarizing plate comprising the same, and a liquid crystal display device including the same.

In recent years, based on the development of optical technology, various plasma display panels (PDPs), liquid crystal displays (LCDs), and organic light emitting diodes (OLEDs) that replace conventional CRTs Display devices using the method have been proposed and marketed. Recently, the characteristics required for these display devices are becoming more advanced, and accordingly, the required properties for peripheral parts such as optical films applied to the display devices are also being advanced. In particular, as display devices have recently become thinner, lighter, and larger in screen area, wide viewing angle, high contrast, suppression of image color change according to viewing angle, and uniformity of screen display have become particularly important problems.

In general, a liquid crystal display device has a basic configuration in which polarizing plates are installed on both sides of a liquid crystal cell, and the orientation of the liquid crystal cell changes depending on whether an electric field is applied to the driving circuit, and accordingly, the transmittance through the polarizing plate is changed, so that light Is made visible. At this time, the light path and birefringence change according to the incident angle of the incident light because the liquid crystal is an anisotropic material having two different refractive indices.

Due to these characteristics, the liquid crystal display device has a disadvantage in that the contrast ratio, which is a measure of how clearly the image is seen according to the viewing angle, changes, and gray scale inversion occurs, resulting in poor visibility. Have In order to overcome this disadvantage, an optical retardation film that expresses an optical retardation occurring in a liquid crystal cell is used in the liquid crystal display device.

As the retardation film applied to the IPS (In-Plaine Switching) mode liquid crystal panel, for example, an optical film having a refractive index distribution of nx> nz> ny should be used. At this time, the optical film having the refractive index distribution as described above is generally known to be difficult to implement uniaxial / biaxially stretched film alone, and the optical film having the refractive index distribution is known as a regular dispersion or a flat dispersion optical film.

However, it has a refractive index distribution of nx> nz> ny as described above, and in the case of an optical film of constant dispersion, a problem that performance deteriorates occurs.

From the above problems, an optical film of reverse dispersion having a refractive index distribution of nx> nz> ny applied to the IPS mode, the manufacturing process is simple, and the phase difference film produced according to the manufacturing process is thinner for the phase difference film Research is ongoing.

Japanese Patent Publication No. 1993-157911

The present invention is to provide a retardation film, a manufacturing method thereof, a polarizing plate comprising the same, and a liquid crystal display device including the same.

One embodiment of the present application, a resin containing a styrene monomer; And a retardation film-forming composition comprising a birefringent modifier having a dichroic value satisfying the following formula (1) or a cured product thereof, the glass transition temperature (Tg) of the retardation film-forming composition. ) Is 115 ° C or higher, and the birefringent modifier is 5 parts by weight or more and 15 parts by weight or less based on 100 parts by weight of the resin containing the styrene-based monomer, and the retardation film satisfies the following formulas (2) to (4). It provides a phosphorus retardation film.

Equation (1): 0.01 ≤ | α _e -α ₀ | ≤ 0.07

Equation (2): nx> nz> ny

Equation (3): 0.7 ≤ Rin (450) / Rin (550) ≤ 1.03

Equation (4): 0.97 ≤ Rin (650) / Rin (550) ≤ 1.2

In the formulas (1) to (4),

α _e is the extinction coefficient of the extraordinary ray, α ₀ is the extinction coefficient of the ordinary ray,

nx is the refractive index in the slow axis direction of the retardation film surface, ny is the refractive index in the fast axis direction of the retardation film surface, nz is the refractive index in the retardation film thickness direction,

Rin (λ) is the plane direction retardation at wavelength λ nm, (nx-ny) x d,

D is the retardation film thickness.

In another embodiment, preparing a heat-shrinkable substrate having a maximum shrinking force in a first direction on a plane; Laminating the retardation film according to claim 1 on the heat-shrinkable substrate; Shrinking in the first direction by applying heat to the heat-shrinkable substrate; And removing the heat-shrinkable substrate, wherein the heat-shrinkable substrate has a shrinkage of 60% or less at a condition of 150 ° C., and a maximum shrinkage force of 5 N / cm ² or more. Provides a manufacturing method.

Another embodiment, the polarizer; And it provides a polarizing plate including at least one retardation film according to an exemplary embodiment of the present application on one surface of the polarizer.

Another embodiment, a liquid crystal cell; An upper polarizing plate provided on an upper layer portion of the liquid crystal cell; A lower polarizing plate provided on the lower layer of the liquid crystal cell; And a backlight unit provided on a lower layer of the lower polarizer, wherein at least one of the upper polarizer and the lower polarizer is a polarizer; And a retardation film according to an exemplary embodiment of the present application disposed on one surface of the polarizer.

The retardation film according to an exemplary embodiment of the present application has a refractive index distribution of nx> nz> ny, and has wavelength dispersion property of reverse dispersion, and the glass transition temperature of the composition for retardation formation is higher than a specific range It has a value and has excellent heat resistance characteristics.

In addition, the retardation film according to an exemplary embodiment of the present application may implement a reverse wavelength / flat wavelength dispersion by changing a wavelength dispersion property using a difference in refractive index with the resin by using a specific content of a birefringent regulator. The retardation film is characterized by generating a relatively uniform degree of phase retardation in a wide light band because the retardation film has an inverse wavelength dispersion property in which the phase retardation value increases as the optical wavelength increases. As a result, when the retardation film of the present invention is applied to a polarizing plate or a display device, it is possible to realize superior color, visual and optical characteristics compared to the prior art.

In addition, in the method of manufacturing the retardation film according to the present invention, the retractable substrate satisfies a specific shrinkage rate and the maximum shrinkage force, so that the retardation film formed therethrough has a refractive index distribution of nx> nz> ny, compared to that implemented by a general stretching process It has the characteristics of simple process steps and cost savings.

1 is a view showing a laminated structure of a polarizing plate according to an exemplary embodiment of the present application.
2 is a view showing a laminated structure of a polarizing plate according to an exemplary embodiment of the present application.
3 is a view showing a liquid crystal display device according to an exemplary embodiment of the present application.

Hereinafter, preferred embodiments of the present invention will be described. However, embodiments of the present invention may be modified in various other forms, and the scope of the present invention is not limited to the embodiments described below. In addition, embodiments of the present invention are provided to explain the present invention in more detail to those skilled in the art.

One embodiment of the present application, a resin containing a styrene monomer; And a retardation film-forming composition comprising a birefringent modifier having a dichroic value satisfying the following formula (1) or a cured product thereof, the glass transition temperature (Tg) of the retardation film-forming composition. ) Is 115 ° C or higher, and the birefringent modifier is 5 parts by weight or more and 15 parts by weight or less based on 100 parts by weight of the resin containing the styrene-based monomer, and the retardation film satisfies the following formulas (2) to (4). It provides a phosphorus retardation film.

Equation (1): 0.01 ≤ | α _e -α ₀ | ≤ 0.07

Equation (2): nx> nz> ny

Equation (3): 0.7 ≤ Rin (450) / Rin (550) ≤ 1.03

Equation (4): 0.97 ≤ Rin (650) / Rin (550) ≤ 1.2

In the formulas (1) to (4),

α _e is the extinction coefficient of the extraordinary ray, α ₀ is the extinction coefficient of the ordinary ray,

nx is the refractive index in the slow axis direction of the retardation film surface, ny is the refractive index in the fast axis direction of the retardation film surface, nz is the refractive index in the retardation film thickness direction,

Rin (λ) is the plane direction retardation at wavelength λ nm, (nx-ny) x d,

D is the retardation film thickness.

The retardation film according to an exemplary embodiment of the present application has a refractive index distribution of nx> nz> ny, and has wavelength dispersion property of reverse dispersion, and the glass transition temperature of the composition for retardation formation is higher than a specific range It has a value and has excellent heat resistance characteristics.

In addition, the retardation film according to an exemplary embodiment of the present application may implement a reverse wavelength / flat wavelength dispersion by changing a wavelength dispersion property using a difference in refractive index with the resin by using a specific content of a birefringent regulator. The retardation film is characterized by generating a relatively uniform degree of phase retardation in a wide light band because the retardation film has an inverse wavelength dispersion property in which the phase retardation value increases as the optical wavelength increases. As a result, when the retardation film of the present invention is applied to a polarizing plate or a display device, it is possible to realize superior color, visual and optical characteristics compared to the prior art.

In this specification, the glass transition temperature was measured using a DSC (Differential Scanning Calorymeter) equipment of METTLER, and the measurement method was performed by adding 3 to 20 mg of resin to be measured in an aluminum crucible at 30 ° C. to 250 ° C. at 10 ° C. per minute. The resin is melted at a heating rate, cooled to 30 ° C again, and then melted at a heating rate of 10 ° C per minute to 200 ° C again. At this time, through the DSC equipment of METTLER, the middle point of the temperature range in which the specific heat behavior of the resin changes heat in the second melting process is measured, and this value is measured as the glass transition temperature value.

In Equation (1), the extinction coefficient α _e of the extraordinary ray and the extinction coefficient α ₀ of the ordinary ray can be calculated by measuring the polarization transmittance of the film containing the birefringent modifier. For example, after attaching a polarizing plate to a light source of a transmittance measuring device (for example, U-3310 manufactured by Hitachi) to generate polarized light, and then transmitting the polarized light to a sample film to measure the transmittance T _o of the normal light , Transmitting polarized light in a state where the sample film is rotated by 90 degrees to measure the transmittance T _e of abnormal light. Then, by substituting the measured normal light transmittance and the abnormal light transmittance into the following equation, the absorption coefficients of the normal light and the abnormal light can be calculated.

-Log T = αbc

(T: transmittance, α: extinction coefficient, b: sample thickness, c: triazine-based birefringent regulator concentration)

In the above formulas (3) and (4), R _in (λ) is a measurement of a plane direction retardation at a wavelength of λnm, and measurement is a value measured using Axoscan from Axometrics. That is, in the above formulas (3) and (4), R _in (450), R _in (550) and R _in (650) mean the plane direction phase difference values at 450 nm, 550 nm and 650 nm, respectively.

The retardation in the plane direction at each wavelength depends on the difference between the refractive index in the slow axis direction and the refractive index in the fast axis direction and the thickness of the retardation film, as described in equations (3) and (4) above. It is determined by. The slow axis and the fast axis are determined according to the orientation direction of the polymer chain of the retardation film. The direction in which the polymer chain is highly oriented is called the slow axis, which is at each wavelength. The direction in which the phase difference delay is long due to the long time for light to pass is called the slow axis. The fast axis is the opposite concept, and the direction in which the polymer chain has a small orientation is called a fast axis, and it takes a short time for light to pass at each wavelength so that the phase difference delay is the smallest. It is called the Fast Axis.

In the formula (3), the plane direction retardation at a wavelength of 550 nm is called R _in (550), and the plane retardation at a wavelength of 450 nm can be referred to as R _in (450). When R _in (450) / R _in (550), the phase difference ratio at two wavelengths, becomes 1 or less, it is called reverse wavelength dispersion, and when it has a value of 1, flat wavelength dispersion, and a value greater than 1, it represents constant wavelength dispersion.

It can be seen that the above formula (4) also exhibits reverse wavelength dispersion / flat wavelength dispersion when R _in (650) / R _in (550) has the range of Equation 4 _{in the} same manner as _in equation (3).

In an exemplary embodiment of the present application, Equation (3) may satisfy 0.7 ≤ Rin (450) / Rin (550) ≤ 1.03, and 0.7 ≤ Rin (450) / Rin (550) ≤ 1.00. .

In an exemplary embodiment of the present application, Equation (4) may satisfy 0.97 ≤ Rin (650) / Rin (550) ≤ 1.2, and 0.97 ≤ Rin (650) / Rin (550) ≤ 1.10. .

In the case of the retardation film according to an exemplary embodiment of the present application, it exhibits a wavelength dispersion property that satisfies Equations (3) and (4) while satisfying the refractive index range of Equation (2), and a liquid crystal containing it later In the case of a display device, it has characteristics that can realize superior color, visual, and optical characteristics compared to the prior art.

In one embodiment of the present application, the resin containing the styrene monomer provides a retardation film that is 20 parts by weight or more and 99 parts by weight or less based on 100 parts by weight of the composition for forming the retardation film.

 In another embodiment, the resin containing the styrene monomer is 20 parts by weight or more and 99 parts by weight or less, preferably 40 parts by weight or more and 98 parts by weight or less, more preferably, based on 100 parts by weight of the composition for forming the retardation film. It may be 50 parts by weight or more and 96 parts by weight or less.

When the resin containing the styrene monomer has the above-mentioned weight range, the glass transition temperature of the composition for forming a phase difference satisfies a value over a specific range, and thus has an effect of greatly increasing the heat resistance of the phase difference film.

In one embodiment of the present application, the birefringent modifier may be 5 parts by weight or more and 15 parts by weight or less based on 100 parts by weight of the resin containing the styrene monomer.

In another exemplary embodiment, the birefringent control agent may be 5 parts by weight or more and 14 parts by weight or less, preferably 5.5 parts by weight or more and 13 parts by weight or less based on 100 parts by weight of the resin containing the styrene monomer.

When the birefringent control agent is included in the content range, the wavelength dispersion of the retardation film may be reduced to 1.0 or less to implement flat / reverse dispersion in normal static dispersion, and has excellent optical properties. When the weight part of the birefringent modifier is smaller than the above range, the wavelength dispersibility has a regular dispersion rather than a normal dispersion / reverse dispersion, and when it is larger than the above range, the phase difference expression is small and sufficient phase difference expression becomes difficult. Have

In one embodiment of the present application, the styrene monomer provides a retardation film that is styrene acrylonitrile (SAN, Styrene acrylonitrile) or styrene maleic anhydride (SMA, Styrene maleicanhydride).

In one embodiment of the present application, the resin containing the styrene monomer is styrene maleic anhydride (SMA, Styrene maleicanhydride), or styrene acrylonitrile (SAN, Styrene acrylonitrile); Or it may be a mixture of styrene maleic anhydride (SMA, Styrene maleicanhydride) and (meth) acrylate-based resin.

In one embodiment of the present application, the (meth) acrylate-based resin may include a (meth) acrylate-based resin having a weight average molecular weight of 100,000 to 5 million.

The weight average molecular weight is a value obtained by averaging the molecular weights of the molecular weights of the component molecular species of the polymer compound having a molecular weight distribution as one of the average molecular weights in which the molecular weight is not uniform and the molecular weight of a certain polymer material is used as a standard.

The weight average molecular weight can be measured through Gel Permeation Chromatography (GPC) analysis.

In the present specification, (meth) acrylate is meant to include both acrylate and methacrylate. The (meth) acrylate-based resin may be, for example, a copolymer of a (meth) acrylic acid ester-based monomer and a crosslinkable functional group-containing monomer.

The (meth) acrylic acid ester-based monomer is not particularly limited, and examples thereof include alkyl (meth) acrylate, and more specifically, as a monomer having an alkyl group having 1 to 12 carbon atoms, pentyl (meth) acrylate, n-butyl (meth) acrylate, ethyl (meth) acrylate, methyl (meth) acrylate, hexyl (meth) acrylate, n-octyl (meth) acrylate, isooctyl (meth) acrylate, 2-ethyl Hexyl (meth) acrylate, dodecyl (meth) acrylate and decyl (meth) acrylate may include one or more kinds.

The crosslinkable functional group-containing monomer is not particularly limited, but may include, for example, one or more of hydroxy group-containing monomer, carboxyl group-containing monomer, and nitrogen-containing monomer.

Examples of the hydroxyl group-containing compound include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, and 6-hydroxyhexyl (meth) ) Acrylate, 8-hydroxyoctyl (meth) acrylate, 2-hydroxyethylene glycol (meth) acrylate, or 2-hydroxypropylene glycol (meth) acrylate.

Examples of the carboxyl group-containing compound include (meth) acrylic acid, 2- (meth) acryloyloxyacetic acid, 3- (meth) acryloyloxypropyl acid, 4- (meth) acryloyloxybutyl acid, acrylic acid double Sieve, itaconic acid, maleic acid, or maleic anhydride.

Examples of the nitrogen-containing monomer include (meth) acrylonitrile, N-vinyl pyrrolidone or N-vinyl caprolactam.

The (meth) acrylate-based resin may also be further copolymerized with at least one of vinyl acetate, styrene, and acrylonitrile from the viewpoint of improving other functions such as compatibility.

In one embodiment of the present application, the resin containing the styrene monomer may be styrene maleic anhydride (SMA, Styrene maleicanhydride).

In one embodiment of the present application, the resin containing the styrene monomer may be a mixture of styrene acrylonitrile (SAN, Styrene acrylonitrile) and (meth) acrylate-based resin.

In one embodiment of the present application, the resin containing the styrene monomer may be a mixture of styrene maleic anhydride (SMA, Styrene maleicanhydride) and (meth) acrylate-based resin.

In particular, when the resin containing the styrene monomer is a mixture of styrene acrylonitrile (SAN, Styrene acrylonitrile) and (meth) acrylate-based resin, the (meth) acrylate-based resin is N-substituted maleimide structure, lac It may have one or more monomers selected from the group consisting of a ton ring structure and a glutarimide structure in an acrylate molecular chain.

The resin containing the styrene monomer is a factor for controlling the glass transition temperature of the composition for forming a phase difference, and when styrene acrylonitrile is used alone, the glass transition temperature is low, causing problems in heat resistance. By mixing with a (meth) acrylate-based resin having a high transition temperature value, the glass transition temperature of the composition for forming a phase difference has a characteristic capable of being formed in a specific range or more. In addition, when using styrene acrylonitrile, when styrene is used alone, the usability with (meth) acrylate resin does not appear, but styrene-acrylonitrile used with acrylonitrile ( By using SAN), the usability with the (meth) acrylate-based resin may be sufficient.

In the (meth) acrylate-based resin, the N-substituted maleimide structure, the lactone ring structure, and the glutarimide structure can be confirmed through nuclear magnetic resonance (NMR) measurement.

In one embodiment of the present application, the N-substituted maleimide structure may be N-phenylmaleimide (PMI).

In the present application, having the monomer in the acrylate molecular chain includes 1 to 40 parts by weight of the monomer based on 100 parts by weight of the acrylic resin, preferably 5 to 30 parts by weight, more preferably 5 to 20 parts by weight It means, and when the monomer is included in the acrylate molecular chain, a copolymer can be formed.

The above-mentioned copolymer is an article obtained by polymerizing two or more different monomers, and the copolymer may have two or more monomers arranged irregularly or regularly.

The copolymer is a random copolymer (Random Copolymer) having a form in which monomers are mixed with each other without a rule, a block copolymer (Block Copolymer) in which blocks arranged in a certain section are repeated, or an alternating form in which monomers are alternately repeated and polymerized. There may be a copolymer (Alternating Copolymer), (meth) acrylate-based resin according to an exemplary embodiment of the present application may be an irregular copolymer, a block copolymer or an alternating copolymer.

In one embodiment of the present application, the (meth) acrylate-based resin is lactone-methyl methacrylate (Lactone-MMA), maleimide-methyl methacrylate (Maleimide-MMA) or glutimide-methylmethacryl Rate (Glutaimide-MMA).

In one embodiment of the present application, the birefringent modulator may be a triazine-based birefringent modulator, and specifically, 2-hydroxyphenyl-s-triazine derivative may be used. Examples include, but are not limited to, Tinuvin 1600, Tinuvin 460, Tinuvin477, Tinuvin479, Tinuvin1577 from BASF, and / or LA-F70, LA46 from ADEKA.

In an exemplary embodiment of the present application, the birefringent modulator may be represented by Formula 1 below.

[Formula 1]

In Chemical Formula 1,

L ₁ to L ₃ are the same as or different from each other, and each independently a direct bond; A substituted or unsubstituted arylene group; Or a substituted or unsubstituted heteroarylene group,

Z ₁ to Z ₃ are the same as or different from each other, and each independently hydrogen; Hydroxy group; A substituted or unsubstituted alkoxy group; A substituted or unsubstituted alkyl group; A substituted or unsubstituted aryl group; Or a substituted or unsubstituted heteroaryl group.

a, b, and c are the same as or different from each other, and each independently an integer of 1 to 3,

p, q, and r are the same as or different from each other, and each independently an integer from 1 to 5. When a, b, c, p, q and r are integers of 2 or more, the substituents in parentheses of 2 or more are the same or different from each other.

Examples of the substituents are described below, but are not limited thereto.

The term "substituted or unsubstituted" as used herein refers to an alkoxy group; Alkyl groups; Aryl group; And substituted or unsubstituted with one or more substituents selected from the group consisting of heterocyclic groups, or substituted or unsubstituted with two or more substituents among the exemplified substituents. For example, "a substituent having two or more substituents" may be a biphenyl group. That is, the biphenyl group may be an aryl group or may be interpreted as a substituent to which two phenyl groups are connected.

In the present specification, the alkyl group may be straight chain or branched chain, and carbon number is not particularly limited, but is preferably 1 to 40. According to an exemplary embodiment, the alkyl group has 1 to 20 carbon atoms. According to another exemplary embodiment, the alkyl group has 1 to 10 carbon atoms. According to another exemplary embodiment, the alkyl group has 1 to 6 carbon atoms. Specific examples of the alkyl group are methyl group, ethyl group, propyl group, n-propyl group, isopropyl group, butyl group, n-butyl group, isobutyl group, tert-butyl group, sec-butyl group, 1-methyl-butyl group, 1-ethyl-butyl group, pentyl group, n-pentyl group, isopentyl group, neopentyl group, tert-pentyl group, hexyl group, n-hexyl group, 1-methylpentyl group, 2-methylpentyl group, 4- Methyl-2-pentyl group, 3,3-dimethylbutyl group, 2-ethylbutyl group, heptyl group, n-heptyl group, 1-methylhexyl group, cyclopentylmethyl group, cyclohexylmethyl group, octyl group, n-octyl group , tert-octyl group, 1-methylheptyl group, 2-ethylhexyl group, 2-propylpentyl group, n-nonyl group, 2,2-dimethylheptyl group, 1-ethyl-propyl group, 1,1-dimethyl- Propyl group, isohexyl group, 4-methylhexyl group, 5-methylhexyl group, and the like, but are not limited to these.

In the present specification, the alkoxy group may be a straight chain, branched chain or cyclic chain. The number of carbon atoms of the alkoxy group is not particularly limited, but is preferably 1 to 40 carbon atoms. Specifically, methoxy, ethoxy, n-propoxy, isopropoxy, i-propyloxy, n-butoxy, isobutoxy, tert-butoxy, sec-butoxy, n-pentyloxy, neopentyloxy, Isopentyloxy, n-hexyloxy, 3,3-dimethylbutyloxy, 2-ethylbutyloxy, n-octyloxy, n-nonyloxy, n-decyloxy, benzyloxy, p-methylbenzyloxy, etc. It may be, but is not limited to this.

Substituents comprising alkyl, alkoxy, and other alkyl group moieties described herein include both straight-chain or ground forms.

In the present specification, the aryl group is not particularly limited, but is preferably 6 to 60 carbon atoms, and may be a monocyclic aryl group or a polycyclic aryl group. According to one embodiment, the carbon number of the aryl group is 6 to 30. According to one embodiment, the carbon number of the aryl group is 6 to 20. The aryl group may be a phenyl group, a biphenyl group, a terphenyl group, etc., as a monocyclic aryl group, but is not limited thereto. The polycyclic aryl group may be a naphthyl group, anthracenyl group, phenanthryl group, pyrenyl group, perylenyl group, triphenyl group, chrysenyl group, fluorenyl group, and the like, but is not limited thereto.

In the present specification, the heterocyclic group is a heteroatom as a heterocyclic group containing one or more of N, O, P, S, Si, and Se, and the number of carbon atoms is not particularly limited, but is preferably 1 to 60 carbon atoms. According to one embodiment, the heterocyclic group has 1 to 30 carbon atoms. Examples of the heterocyclic group include, for example, pyridyl group, pyrrol group, pyrimidyl group, pyridazinyl group, furanyl group, thiophenyl group, imidazole group, pyrazole group, oxazole group, isoxazole group, thiazole group, isothiazole group, Triazole group, oxadiazole group, thiadiazole group, dithiazole group, tetrazole group, pyranyl group, thiopyranyl group, pyrazinyl group, oxazinyl group, thiazinyl group, dioxynyl group, triazinyl group, tetrazinyl group, quie Nolinyl group, isoquinolinyl group, quinolyl group, quinazolinyl group, quinoxalinyl group, naphthyridinyl group, acridil group, xanthenyl group, phenanthridinyl group, diazanaphthalenyl group, triazindenyl group, indole group , Indolinyl group, indolizinyl group, phthalazinyl group, pyrido pyrimidinyl group, pyrido pyrazinyl group, pyrazino pyrazinyl group, benzothiazole group, benzoxazole group, benzimidazole group, benzothiophene group , Benzofuranyl group, dibenzothiophenyl group, dibenzofuranyl group, carbazole group, benzocarbazole group, dibenzocarbazole group, indolocarbazole group, indenocarbazole group, phenazinyl group, imidazopyridine group, phenoxazinyl group , Phenanthridine group, phenanthroline group, phenothiazine group, imidazopyridine group, imidazophenanthridine group. Benzoimidazoquinazoline groups, or benzoimidazophenanthridine groups, and the like, but are not limited thereto.

In the present specification, the description of the aforementioned heterocyclic group may be applied, except that the heteroaryl group is aromatic.

In the present specification, the description of the aryl group described above may be applied, except that the arylene group is a divalent group.

In one embodiment of the present application, L ₁ to L ₃ are a direct bond; Or it may be a substituted or unsubstituted arylene group having 6 to 60 carbon atoms.

In another exemplary embodiment, L ₁ to L ₃ are a direct bond; Or it may be a substituted or unsubstituted arylene group having 6 to 40 carbon atoms.

In another exemplary embodiment, L ₁ to L ₃ are a direct bond; Or it may be a phenylene group.

In an exemplary embodiment of the present application, Z ₁ to Z ₃ are hydrogen; Hydroxy group; A substituted or unsubstituted aryl group having 6 to 60 carbon atoms; Or it may be a substituted or unsubstituted alkoxy group.

In another exemplary embodiment, Z ₁ to Z ₃ is hydrogen; Hydroxy group; A substituted or unsubstituted aryl group having 6 to 40 carbon atoms; Or it may be a substituted or unsubstituted alkoxy group.

In another exemplary embodiment, Z ₁ to Z ₃ is hydrogen; Hydroxy group; An aryl group having 6 to 40 carbon atoms; Or it may be an alkoxy group substituted or unsubstituted with an alkyl group having 1 to 40 carbon atoms.

In another exemplary embodiment, Z ₁ to Z ₃ is hydrogen; Hydroxy group; Phenyl group; Or it may be an alkoxy group unsubstituted or substituted with a branched alkyl group having 1 to 10 carbon atoms.

In one embodiment of the present application, Formula 1 may be represented by Formula 2 below.

[Formula 2]

In Chemical Formula 2, the definitions of Z ₁ to Z ₃ , p, q and r are the same as those in Chemical Formula 1.

In one embodiment of the present application, at least one of Z ₁ to Z ₃ may be a substituted or unsubstituted aryl group.

In particular, when at least one of the Z ₁ to Z ₃ has a phenyl group, the difference in birefringence is greater than that in the case where it is not, and due to the structural difference in the birefringent modulator, the Z ₁ to Z ₃ do not have a birefringent modifier Even in the case of overdose, the effect is small.

In particular, in an exemplary embodiment of the present application, when using BASF's Tinuvin 1600 (2-hydroxyphenyl-s-triazine derivative) as a birefringent modulator, the effect of improving wavelength dispersibility compared to a similar content was most noticeable, which is a structural difference. It may be due to the difference in birefringence.

In one embodiment of the present application, the thickness of the retardation film is 10 μm or more and 180 μm It may be:

In another exemplary embodiment, the thickness of the retardation film is 10 μm or more and 180 μm. Hereinafter, preferably 30 μm or more and 160 μm Hereinafter, more preferably 60 μm or more and 140 μm It may be:

As can be seen from the above equations (3) and (4), the retardation value varies depending on the thickness of the retardation film, and in the present application, when the thickness of the retardation film has the above range, it has a flat dispersion / reverse dispersion.

In an exemplary embodiment of the present application, preparing a heat-shrinkable substrate having a maximum shrinking force in a first direction on a plane; Laminating the retardation film according to claim 1 on the heat-shrinkable substrate; Shrinking in the first direction by applying heat to the heat-shrinkable substrate; And removing the heat-shrinkable substrate, wherein the heat-shrinkable substrate has a shrinkage of 60% or less at a condition of 150 ° C., and a maximum shrinkage force of 5 N / cm ² or more. Provides a manufacturing method.

In the present invention, the retardation film may be produced through melt / extrusion.

In the present invention, the retardation film may be produced through solution casting.

In one embodiment of the present application, the step of laminating the retardation film according to claim 1 on the heat-shrinkable substrate is heat-shrinkable through the pressure sensitive adhesive (PSA) of the fabric of the retardation film according to the present application. It may be a step of lamination to a substrate.

In one embodiment of the present application, there is provided a method of manufacturing a retardation film, further comprising stretching the retardation film before the step of laminating the retardation film on the heat-shrinkable substrate.

In one embodiment of the present application, after the step of shrinking in the first direction by applying heat to the heat-shrinkable substrate, further comprising stretching in a direction perpendicular to the first direction and the plane of the retardation film Provides a manufacturing method.

In one embodiment of the present application, the stretching ratio of the step of stretching the retardation film before the step of laminating the retardation film on the heat-shrinkable substrate may be 1.02 times or more, preferably 1.1 times or more.

In another embodiment, the stretching ratio of the step of stretching the retardation film before the step of laminating the retardation film on the heat-shrinkable substrate may be 5 times or less, preferably 4 times or less.

Before the step of laminating the retardation film on the heat-shrinkable substrate, the stretching direction of the step of stretching the retardation film may include both a machine direction (MD) and a transverse direction (TD) perpendicular thereto.

In one embodiment of the present application, there is provided a method of manufacturing a retardation film having a draw ratio of a step of stretching in a direction perpendicular to the first direction and the plane is 2 times or less.

The stretching ratio in the step of stretching in a direction perpendicular to the first direction is measured based on the length of the stretching direction, and the stretching ratio is 2 times or less, preferably 1.8 times or less, more preferably 1.5 times It can have the following values.

In another exemplary embodiment, the stretching ratio of the step of stretching in a direction perpendicular to the first direction and the plane may have a value of 1.05 times or more, preferably 1.1 times or more.

In the method of manufacturing the retardation film according to the present application, when the stretching ratio of the step of stretching in the direction perpendicular to the first direction and the plane satisfies the above range, the retardation film is not damaged in the stretching process, Accordingly, it has a characteristic that the appearance is not damaged.

The stretching process may perform longitudinal (MD) stretching or transverse (TD) stretching. In the case of longitudinal stretching, stretching can be performed by a difference in speed between rolls, and in the case of transverse stretching, tenta can be used.

The stretching temperature is preferably in the range near the glass transition temperature of the retardation film for conditions above the temperature at which the heat-shrinkable substrate can shrink, and when the glass transition temperature of the retardation film composition is Tg, preferably (Tg-30 ° C) to (Tg + 100 ° C), more preferably (Tg-20 ° C) to (Tg + 50 ° C), more preferably (Tg-20 ° C) to (Tg + 30 ° C) Is within the scope of If the stretching temperature is less than (Tg-30 ° C), there is a fear that the stretching may not be smoothly performed at a low processing temperature. Conversely, if the stretching temperature exceeds (Tg + 100 ° C), there is a fear that stable stretching cannot be performed under too high a processing temperature condition.

When the retardation film is produced through melt / extrusion and solution casting, the retardation film surface may be flattened and remain in the retardation film before stretching in the direction perpendicular to the first direction. In order to volatilize the included solvent, a drying process may be further performed.

In one embodiment of the present application, the step of stretching may be omitted.

In an exemplary embodiment of the present application, a refractive index distribution of the retardation film after the step of shrinking in the first direction by applying heat to the heat-shrinkable substrate satisfies the following formula (5). to provide.

Equation (5)

ny <nz <nx

In the formula (5),

nx is the refractive index in the direction in which the refractive index is maximum with respect to the plane direction,

ny means the refractive index in the direction perpendicular to the nx direction,

nz means the refractive index in the thickness direction.

The refractive index of the general stretched retardation film has birefringence such as nz> nx> ny, nx> ny> nz, nz> nx = ny, nx = ny> nz, and a retardation film satisfying the refractive index distribution of nx> nz> ny Although it is difficult to implement as a general stretching process, when preparing the retardation film according to the present application through the above manufacturing method, a retardation film satisfying the refractive index distribution of the formula (5) can be formed.

In one embodiment of the present application, the refractive index distribution of the retardation film after the step of shrinking in the first direction by applying heat to the heat-shrinkable substrate satisfies the following equations (6) to (8) Provided is a method of manufacturing a film.

Equation (6)

100nm <R _in <500nm

Equation (7)

50nm <R _th <250nm

Equation (8)

0 <Nz <1

In the formulas (6) to (8),

R _in can be represented by (nx-ny) xd,

R _th can be expressed as (nz-ny) xd,

Nz is the value of (nx-nz) / (nx-ny),

D is the thickness of the retardation film,

The nx is a refractive index in a direction in which the refractive index is maximum with respect to the plane direction,

The ny means a refractive index in a direction perpendicular to the nx direction,

The nz means a refractive index in the thickness direction.

In one embodiment of the present application, the heat-shrinkable substrate has a maximum shrinking force in a first direction on a plane, and the first direction means a direction in which the degree of contraction is greatest, and the first direction in the present application Is the same as the shrinking direction of the heat-shrinkable substrate.

In one embodiment of the present application, the heat-shrinkable substrate may have a shrinkage of 60% or less under the conditions of 150 ° C.

In another exemplary embodiment, the heat-shrinkable substrate may have a shrinkage of 60% or less, preferably 55% or less, and more preferably 50% or less under the conditions of 150 ° C.

In another exemplary embodiment, the heat-shrinkable substrate may have a shrinkage of 10% or more, preferably 15% or more, and more preferably 25% or more under conditions of 150 ° C.

The shrinkage rate of the heat-shrinkable substrate may mean a value of (L1-L2) / L1 * 100 (%) when the initial length of the heat-shrinkable substrate is L1 and the length contracted by shrinkage is L2.

In one embodiment of the present application, the maximum shrinkage force generated when the heat-shrinkable substrate is contracted may be 5 N / cm ^{2 or} more.

In another exemplary embodiment, the maximum shrinkage force generated when the heat-shrinkable substrate is contracted may be 5 N / cm ² or more, preferably 7 N / cm ² or more, and more preferably 12 N / cm ^{2 or} more.

In another exemplary embodiment, the maximum shrinkage force generated during shrinkage of the heat-shrinkable substrate may be 10,000 N / cm ² or less, preferably 8,000 N / cm ² or less, and more preferably 5,000 N / cm ² or less.

In an exemplary embodiment of the present application, the shrinkage may be calculated by cutting the shrinkable substrate in a square shape of 5 cm each in a horizontal x vertical direction and staying at a temperature of 150 ° C. for 5 minutes to measure the contracted length.

In an exemplary embodiment of the present application, the shrinkage force is cut so that the shrinkable base film is 2 cm wide and 10 cm long, and is mounted so that the sample length (UTM zig length) is 5 cm on a UTM (Universal Tensile Machine) equipment equipped with a high temperature oven chamber After that, it is possible to measure the force contracted at 150 ° C by recording the force contracted at 150 ° C by allowing the zig site equipped with the shrinkable substrate sample to enter a chamber set at a high temperature of 150 ° C. N) is measured by reflecting the width (2 cm) and thickness values of the film, cm ² It is the value expressed by the sugar contracting force.

The maximum contraction force of the heat-shrinkable substrate refers to a force in which the heat-shrinkable substrate is to be restored to its original state after contraction, and the maximum shrinkage force is a force to restore the original state at the maximum shrinkage rate at which the heat-shrinkable substrate can be restored. Means

When the heat-shrinkable substrate has the range of the shrinkage rate and the maximum shrinkage force range, the rate of change in shrinkage dimension of the composition for forming a retardation film coated on the shrinkable substrate is suitable, so as not to be damaged according to the shrinkage change, and to have an appearance that is not deformed. In addition, it also has a characteristic that can form a retardation film having a specific refractive index range and wavelength dispersion.

In one embodiment of the present application, the heat shrinkable substrate is PET (polyethylene terephthalate), polyester (polyester), PC (Polycarbonate), polyolefin (Polyolefin), PCO (polycylicolefin), polystyrene (Polystyrene), COP (cycloolefin polymer) ), Acrylic polymer, polyimide (PI), polyethylene naphthalate (PEN), polyether ether ketone (PEK), polyarylate (PAR), polynorbornene, and polyethersulphone (PES). Can be.

In another exemplary embodiment, the heat-shrinkable substrate may be PET (polyethylene terephthalate).

The retardation film may be subjected to heat treatment (annealing) or the like after stretching treatment in order to stabilize its optical isotropy or mechanical properties. The conditions for heat treatment are not particularly limited and any suitable conditions known to those skilled in the art of the present invention can be employed.

The retardation film of the present invention as described above may be usefully applied to a polarizing plate and / or a liquid crystal display device. In one embodiment of the present invention, the present invention is a polarizer; And it provides a polarizing plate comprising at least one phase difference film of the present application.

1 is a view showing a laminated structure of the polarizing plate 103 according to an exemplary embodiment of the present application. Specifically, the polarizing plate 103 has a structure in which a polarizer 102 and a phase difference film 101 are stacked on one surface of the polarizer.

In one embodiment of the present application, the polarizer is not particularly limited, and a polarizer well known in the art, for example, a film made of polyvinyl alcohol (PVA) containing iodine or dichroic dye is used.

The polarizer exhibits a characteristic that only light that vibrates in one direction can be extracted from light that is incident while vibrating in various directions. This property can be achieved by stretching polyvinyl alcohol (PVA) absorbing iodine with strong tension. For example, more specifically, swelling by swelling a PVA film in an aqueous solution, swelling with a dichroic material that imparts polarization to the swollen PVA film, and stretching the dyed PVA film ) To form a polarizer through a stretching step of arranging the dichroic dye material side by side in a stretching direction, and a complementary color step of correcting the color of the PVA film that has undergone the stretching step. However, the polarizing plate of the present invention is not limited thereto.

In an exemplary embodiment of the present application, the polarizer and the retardation film may be adhered with an adhesive, and the usable adhesive is not particularly limited as long as it is known in the art. For example, there are water-based adhesives, one-component or two-component polyvinyl alcohol (PVA) -based adhesives, polyurethane-based adhesives, epoxy-based adhesives, styrene-butadiene rubber-based (SBR-based) adhesives, or hot melt adhesives, but the present invention It is not limited to these examples.

The retardation film may be directly attached to one or both sides of the polarizer. In addition, it is attached to the protective film of the conventional polarizing plate with a protective film on both sides of the polarizer, it can be usefully used as a retardation film.

When the retardation film is directly attached to one side or both sides of the polarizer, for example, the structure may be a phase protection film / polarizer / phase difference film or a phase difference film / polarizer / bottom protection film. The attachment method is to apply a primer to the surface of the retardation film or polarizer using a roll coater, gravure coater, bar coater, knife coater, capillary coater, or micro chamber doctor blade coater, etc. , Sprinkling the adhesive in a droplet manner, may be performed by a method of heating and laminating a laminate comprising a retardation film and a polarizer with a lamination roll, a method of laminating by pressing at normal temperature, or a method of UV curing.

2 is a view showing a laminated structure of a polarizing plate according to an exemplary embodiment of the present application. Specifically, the polarizing plate 103 may have a structure in which the polarizer protective film 104 / adhesive layer 105 / phase difference film 101 / polarizer 102 / polarizer protective film 104 are sequentially stacked.

In an exemplary embodiment of the present application, a polarizer protective film is attached to one surface of the polarizer, and a retardation film according to the present application is attached to a surface opposite to the surface to which the polarizer protective film of the polarizer is attached. do.

In one embodiment of the present application, the polarizer protective film is a COP (cycloolefin polymer) film, acrylic film, TAC (triacetylcellulose) film, COC (cycloolefin copolymer) film, PNB (polynorbornene) film and PET (polyethylene) terephtalate) -based film.

In one embodiment of the present application, there is provided a liquid crystal display device including the polarizing plate.

In addition, an exemplary embodiment of the present application is a liquid crystal cell; An upper polarizing plate provided on an upper layer portion of the liquid crystal cell; A lower polarizing plate provided on the lower layer of the liquid crystal cell; And a backlight unit provided on a lower layer of the lower polarizer, wherein at least one of the upper polarizer and the lower polarizer is a polarizer; And a retardation film according to an exemplary embodiment of the present application disposed on one surface of the polarizer.

In one embodiment of the present application, the upper polarizing plate is the polarizer; And the retardation film, wherein the retardation film is disposed to face the liquid crystal cell.

In one embodiment of the present application, the lower polarizing plate is the polarizer; And the retardation film, wherein the retardation film is disposed to face the backlight unit.

The upper polarizing plate is the polarizer; And the retardation film, wherein the retardation film is disposed to face the liquid crystal cell, wherein the upper polarizer is the polarizer; And the retardation film, which means that the retardation film at this time is disposed in the liquid crystal cell direction in the liquid crystal display device, and specifically, the backlight unit / lower polarizer / liquid crystal cell / phase difference film / polarizer are sequentially stacked. It means having a structure.

The lower polarizing plate may include the polarizer; And the retardation film, wherein the retardation film is disposed to face the backlight unit, wherein the lower polarizing plate includes the polarizer; And the retardation film, which means that the retardation film at this time is disposed in the direction of the backlight unit in the liquid crystal display, and specifically, the backlight unit / polarizer / phase difference film / liquid crystal cell / top polarizing plate are sequentially stacked. It means having a structure.

In the liquid crystal display device according to the present application, when the phase difference film of the upper polarizing plate is disposed to face the liquid crystal cell, or when the phase difference film of the lower polarizing plate is disposed to face the backlight unit, included in the phase difference film The triazine-based birefringent modulator may have a main purpose of improving the function of the panel with the phase difference expression function, not the main function of ultraviolet absorption.

The backlight unit includes a light source that irradiates light from the rear surface of the liquid crystal panel, and the type of the light source is not particularly limited, and a general LCD light source such as CCFL, HCFL or LED can be used.

3 is a view showing a liquid crystal display device according to an exemplary embodiment of the present application. Specifically, the upper polarizing plate 11 and the lower polarizing plate 12 may be stacked on both sides of the liquid crystal cell 10, and the surface contacting the liquid crystal cell 10 of the lower polarizing plate 12 close to the backlight unit 14 and The protective film 13 may be stacked on the opposite side. As the upper polarizing plate 11 and the lower polarizing plate 12, a polarizing plate according to an exemplary embodiment of the present application may be used, and preferably, a polarizing plate according to an exemplary embodiment of the present application may be used as the lower polarizing plate 12.

The protective film is the same as the contents of the polarizer protective film described above.

Hereinafter, the operation and effects of the invention will be described in more detail through specific examples of the invention. However, these examples are only presented as examples of the invention, and the scope of the invention is not thereby determined.

< Manufacturing example >

< Phase difference  Film production>

The retardation film was laminated on a heat shrinkable substrate through a pressure-sensitive adhesive to form a laminate. The heat-shrinkable substrate was shrunk in an oven according to the temperature shown in Table 1 below, and the laminated film thus laminated was stretched in the direction and magnification shown in Table 1 below before laminating the retardation film, if necessary. When necessary, the heat-shrinkable substrate was shrunk and uniaxially stretched in a direction perpendicular to the shrinking direction.

Then, the heat shrinkable substrate was peeled to form a retardation film satisfying the conditions and physical properties of Table 1 below.

1. Shrinkage (%): The heat shrinkable substrate was cut into square shapes of 5 cm each in width x length to stay at 150 ° C. for 5 minutes, and then the shrinked length was measured to calculate the shrinkage.

2. Shrinkage (N / cm ² ): The heat shrinkable base film is cut into ² cm wide and 10 cm long, and attached to a UTM (Universal Tensile Machine) equipped with a high temperature oven chamber so that the sample length (UTM zig length) is 5 cm. Then, by recording the force (N) that contracts at 150 ° C. by recording the zig site with the sample of shrinkable substrate entering the chamber set at a high temperature of 150 ° C., the force N contracted Measuring film width (2cm) and thickness values reflecting cm ² It is the value expressed by the sugar contracting force.

In Table 1, Examples 1 to 3 were produced by using a birefringent modifier of SMA alone, and in Example 1, after the retardation film layer was slightly stretched in the vertical direction in the direction to shrink before laminating with the heat shrinkable substrate. It is produced by laminating with a heat-shrinkable substrate and shrinking and further stretching, and Examples 2 and 3 are produced by laminating a heat-shrinkable substrate before lamination, before and after laminating a retardation film without stretching, and then shrinking and stretching the heat-shrinkable substrate.

In the case of Example 4, it was prepared using a birefringent modifier comprising heat-resistant PMMA and SAN, and before being laminated to a heat-shrinkable substrate, stretching was increased vertically in the direction to shrink (3.0 times) and stretched in the direction to shrink. After making it small (1.3 times), it was laminated with a heat-shrinkable substrate to produce shrinkage and stretching.

The Comparative Examples 1 to 3 correspond to the Examples 1 to 3, and the wavelength dispersion is set as a constant wavelength by putting the content of the birefringent modifier in a composition for forming a retardation film less, and in the case of Comparative Example 4, in Table 1, As can be seen, before the shrinkage of the heat-shrinkable substrate, it can be seen that the retardation film is relatively larger in the vertical direction in the direction to be shrunk, and also, the shrinkage of the heat-shrinkable substrate is low, so that the retardation film of the present application is low. It was confirmed that the expression (2) was not satisfied, and the Nz value also did not represent a value between 0 and 1.

101: retardation film
102: polarizer
103: polarizer
104: polarizer protective film
105: adhesive layer
10: liquid crystal cell
11: upper polarizer
12: lower polarizer
13: Protective film
14: backlight unit

Claims (18)

Resins containing styrene monomers; And
A birefringent modulator having a dichroic value satisfying the following formula (1);
A composition for forming a retardation film comprising or a retardation film comprising a cured product thereof,
The retardation film forming composition has a glass transition temperature (Tg, glass transition temperature) of 115 ° C or higher,
The birefringent modifier is 5 parts by weight or more and 15 parts by weight or less based on 100 parts by weight of the resin containing the styrene monomer,
The retardation film is a retardation film that satisfies the following formulas (2) to (4):
Equation (1): 0.01 ≤ | α _e -α ₀ | ≤ 0.07
Equation (2): nx>nz> ny
Equation (3): 0.7 ≤ Rin (450) / Rin (550) ≤ 1.03
Equation (4): 0.97 ≤ Rin (650) / Rin (550) ≤ 1.2
In the formulas (1) to (4)
α _e is the extinction coefficient of the extraordinary ray, α ₀ is the extinction coefficient of the ordinary ray,
nx is the refractive index in the slow axis direction of the retardation film surface, ny is the refractive index in the fast axis direction of the retardation film surface, nz is the refractive index in the retardation film thickness direction,
Rin (λ) is the planar phase difference at wavelength λ nm, (nx-ny) xd,
D is the retardation film thickness. The method according to claim 1,
The resin containing the styrene monomer, the phase difference film that is 20 parts by weight or more and 99 parts by weight or less based on 100 parts by weight of the composition for forming the retardation film. The method according to claim 1,
The styrene monomer is a styrene acrylonitrile (SAN, Styrene acrylonitrile) or styrene maleic anhydride (SMA, Styrene maleicanhydride) is a retardation film. The method according to claim 1,
The resin containing the styrene monomer is styrene maleic anhydride (SMA, Styrene maleicanhydride), or styrene acrylonitrile (SAN, Styrene acrylonitrile); Or a retardation film that is a mixture of styrene maleic anhydride (SMA, Styrene maleicanhydride) and a (meth) acrylate-based resin. The retardation film according to claim 4, wherein the (meth) acrylate-based resin has at least one monomer selected from the group consisting of an N-substituted maleimide structure, a lactone ring structure, and a glutarimide structure in an acrylate molecular chain. The method according to claim 1,
The retardation film has a thickness of 10 μm or more and 180 μm. The retardation film which is the following. Preparing a heat-shrinkable substrate having a maximum shrinking force in a first direction on a plane;
Laminating the retardation film according to claim 1 on the heat-shrinkable substrate;
Shrinking in the first direction by applying heat to the heat-shrinkable substrate; And
Removing the heat-shrinkable substrate;
As a method of manufacturing a retardation film comprising a,
The heat-shrinkable substrate is a method of manufacturing a retardation film having a shrinkage of 60% or less and a maximum shrinkage of 5 N / cm ² or more under conditions of 150 ° C. The method according to claim 7,
Before laminating the retardation film on the heat-shrinkable substrate
The method of manufacturing a retardation film further comprising the step of stretching the retardation film. The method according to claim 7,
After the step of shrinking in the first direction by applying heat to the heat-shrinkable substrate, further comprising the step of stretching in a direction perpendicular to the first direction and the plane. The method according to claim 7,
A method of manufacturing a retardation film, wherein the refractive index distribution of the retardation film after the step of shrinking in the first direction by applying heat to the heat-shrinkable substrate satisfies Equation (5) below:
Equation (5)
ny <nz <nx
In the formula (5),
nx is the refractive index in the direction in which the refractive index is maximum with respect to the plane direction,
ny means the refractive index in the direction perpendicular to the nx direction,
nz means the refractive index in the thickness direction. The method according to claim 7,
A method of manufacturing a retardation film in which the refractive index distribution of the retardation film after the step of shrinking in the first direction by applying heat to the heat-shrinkable substrate satisfies the following formulas (6) to (8):
Equation (6)
100nm <R _in <500nm
Equation (7)
50nm <R _th <250nm
Equation (8)
0 <Nz <1
In the formulas (6) to (8),
R _in can be represented by (nx-ny) xd,
R _th can be expressed as (nz-ny) xd,
Nz is the value of (nx-nz) / (nx-ny),
D is the thickness of the retardation film,
The nx is a refractive index in a direction in which the refractive index is maximum with respect to the plane direction,
The ny means a refractive index in a direction perpendicular to the nx direction,
The nz means a refractive index in the thickness direction. The method according to claim 9,
The method of manufacturing a retardation film having a draw ratio of a step of stretching in a direction perpendicular to the first direction and a plane is 2 times or less. The method according to claim 7,
The heat shrinkable substrate is PET (polyethylene terephthalate), polyester (polyester), PC (Polycarbonate), polyolefin (Polyolefin), PCO (polycylicolefin), polystyrene (Polystyrene), COP (cycloolefin polymer), acrylic polymer (Acrylic polymer), A method for producing a phase difference film selected from the group consisting of polyimide (PI), polyethylene naphthalate (PEN), polyether ether ketone (PEK), polyarylate (PAR), polynorbornene, and polyethersulphone (PES). Polarizer; And
A polarizing plate comprising at least one retardation film of any one of claims 1 to 6. The method according to claim 14,
A polarizer protective film is attached to one surface of the polarizer,
A polarizing plate in which the retardation film is attached to a surface opposite to the surface to which the polarizer protective film of the polarizer is attached. Liquid crystal cell;
An upper polarizing plate provided on an upper layer portion of the liquid crystal cell;
A lower polarizing plate provided on the lower layer of the liquid crystal cell; And
It includes a backlight unit provided on the lower layer of the lower polarizing plate,
At least one of the upper polarizing plate and the lower polarizing plate is a polarizer; And a retardation film of any one of claims 1 to 6 disposed on one surface of the polarizer. The method according to claim 16,
The upper polarizing plate is the polarizer; And the retardation film,
The retardation film is disposed so as to face the liquid crystal cell. The method according to claim 16,
The lower polarizing plate may include the polarizer; And the retardation film,
The retardation film is disposed so as to face the backlight unit.

Images