KR20210049384A - Composition for retardation film, retardation film, polarizing plate comprising same, liquid crystal display device comprising same and organic light emitting diode display device comprising same - Google Patents

Abstract

The present invention relates to a retardation film composition, a retardation film, a polarizing plate comprising the same, and a liquid crystal display including the same and an organic light emitting device display including the same. The retardation film composition comprising an ethyl cellulose resin having positive birefringence; and a styrene-maleic acid-ester (SMA) resin having negative birefringence can implement specific reverse wavelength dispersion properties by changing wavelength dispersion properties.

Description

A retardation film composition, a retardation film, a polarizing plate including the same, a liquid crystal display including the same, and an organic light emitting device display including the same. DIODE DISPLAY DEVICE COMPRISING SAME}

The present invention relates to a retardation film composition, a retardation film, a polarizing plate including the same, a liquid crystal display including the same, and an organic light emitting device display including the same.

Based on the recent development of optical technology, various types of plasma display panels (PDP), liquid crystal displays (LCDs), organic light emitting diodes (OLEDs), etc., which replace conventional CRT, Display devices using the method are proposed and marketed. Recently, the characteristics required for these display devices are becoming more advanced, and accordingly, the characteristics required for peripheral components such as an optical film applied to a display device are also increasing. In particular, in recent years, as display devices have been promoted to be thinner, lighter, and larger in screen area, a wide viewing angle, high contrast, suppression of image color change depending on the viewing angle, and uniform screen display have become particularly important issues.

The retardation film is an optical film used in a display device for the purpose of improving a viewing angle and improving display quality, and can be classified into one having a positive wavelength dispersion, a flat wavelength dispersion, and a reverse wavelength dispersion according to the wavelength dispersion characteristics. A retardation film having a constant wavelength dispersion property refers to a retardation film having a characteristic that a retardation value generated as the wavelength of incident light increases, and a retardation film having a flat wavelength dispersion property has a similar degree regardless of the wavelength of the incident light. It means a retardation film having a characteristic in which a retardation value is generated, and a retardation film having a reverse wavelength dispersion property means a retardation film having a characteristic in which a retardation value generated as the wavelength of incident light increases.

Most of the retardation films developed so far have a constant wavelength dispersion property or a flat wavelength dispersion property, but in the case of a retardation film having a constant wavelength dispersion property or a flat wavelength dispersion property, the degree of phase delay changes as the light wavelength changes. There is a problem in that it is difficult to obtain a uniform color or visual sense. On the other hand, in the case of having reverse wavelength dispersion, the phase delay value increases as the optical wavelength increases, and thus, it is attracting attention in that a relatively uniform phase delay can be implemented in a relatively wide optical wavelength band.

However, since wavelength dispersibility is a characteristic that appears uniquely depending on the material of the retardation film, in order to manufacture a retardation film having reverse wavelength dispersion in one sheet, it is necessary to find a new raw material, which is not easy in reality. Therefore, conventionally, two or more retardation films having different wavelength dispersion properties are laminated using an adhesive or an adhesive to prepare a retardation film having reverse wavelength dispersion, or a resin having a positive retardation value and a resin having a negative phase difference value are used. A method of producing a retardation film having reverse wavelength dispersion by extruding to form a laminate and stretching it has been proposed.

However, in the case of the first method, if the optical axes of the two retardation films to be stacked are not accurately arranged, there is a problem that the reverse wavelength dispersion is not exhibited, and manufacturing is very difficult. In the second method, the resin forming each layer If the glass transition temperature is not similar, since stretching does not occur properly, there is a problem that the usable resin is limited.

In addition, in the case of a retardation film in which wavelength dispersion is improved by reverse wavelength dispersion, the glass transition temperature is very low, resulting in a problem of poor heat resistance.

Therefore, there is a need for development of a retardation film that is easy to manufacture, has excellent heat resistance, and can implement reverse wavelength dispersion.

Korean Public Publication No. 2005-0101743

An object of the present invention is to provide a retardation film, a polarizing plate including the same, a liquid crystal display including the same, and an organic light emitting device display including the same.

An exemplary embodiment of the present application, ethyl cellulose resin having a positive birefringence; And a styrene-maleic acid-ester (SMA) resin having negative birefringence, wherein the weight average molecular weight of the styrene-maleic acid-ester (SMA) resin having negative birefringence is 80,000 g /mol or more, and the ethylcellulose resin having the positive birefringence: provides a retardation film composition in which the styrene-maleic acid-ester (SMA) resin having negative birefringence satisfies 70:30 to 30:70 .

Another exemplary embodiment provides a retardation film including the retardation film composition or a cured product thereof according to an exemplary embodiment of the present application.

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

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

Finally, an exemplary embodiment of the present application is an organic light emitting device (OLED) panel; And an upper polarizing plate provided on the organic light emitting element (OLED) panel, wherein the upper polarizing plate includes a polarizer; And it is intended to provide an organic light-emitting device (OLED) display including the retardation film according to the present application disposed on one surface of the polarizer.

The retardation film composition according to the present invention includes an ethyl cellulose resin having a positive birefringence; And a styrene-maleic acid-ester (SMA) resin having negative birefringence, and an ethylcellulose resin having the positive birefringence: styrene-maleic acid-ester (SMA) resin having a negative birefringence is 70: By satisfying 30 to 30:70, it has a characteristic capable of implementing a specific reverse wavelength dispersion by changing the wavelength dispersion.

In order to implement a specific reverse wavelength dispersion as described above, the styrene-maleic acid-ester (SMA) resin having negative birefringence should contain 30 parts by weight or more, and accordingly, in the retardation film composition according to the present application The weight average molecular weight of the included styrene-maleic acid-ester (SMA) resin having negative birefringence is 80,000 g/mol or more, so that filming problems do not occur when forming a retardation film in the future. .

The retardation film including the retardation film composition according to the present invention has a reverse wavelength dispersion property that increases the phase retardation value as the optical wavelength increases, and thus has a characteristic capable of generating a relatively uniform degree of phase retardation in a wide optical band. do. As a result, when the retardation film of the present invention is applied to a polarizing plate or a liquid crystal display device, it has characteristics capable of realizing superior color, visibility, and optical characteristics compared to the conventional one.

In addition, the organic light-emitting device (OLED) display including the retardation film according to the present application has excellent anti-reflection properties not only in the front direction of the screen, but also in the oblique direction.

1 is a diagram showing a stacked structure of a polarizing plate according to an exemplary embodiment of the present application.
2 is a diagram showing a stacked structure of a polarizing plate according to an exemplary embodiment of the present application.
3 is a diagram illustrating a liquid crystal display according to an exemplary embodiment of the present application.
4 is a diagram showing a schematic lamination structure of an organic light emitting diode (OLED) display 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 with average knowledge in the art.

An exemplary embodiment of the present application, ethyl cellulose resin having a positive birefringence; And a styrene-maleic acid-ester (SMA) resin having negative birefringence, wherein the weight average molecular weight of the styrene-maleic acid-ester (SMA) resin having negative birefringence is 80,000 g /mol or more, and the ethylcellulose resin having the positive birefringence: provides a retardation film composition in which the styrene-maleic acid-ester (SMA) resin having negative birefringence satisfies 70:30 to 30:70 .

In the exemplary embodiment of the present application, the ethylcellulose resin having positive birefringence: styrene-maleic acid-ester (SMA) resin having negative birefringence is 70:30 to 30:70 in the phase difference film composition. It means the content ratio of ethyl cellulose resin having positive birefringence and styrene-maleic acid-ester (SMA) resin having negative birefringence.

The retardation film composition according to the present invention includes an ethyl cellulose resin having a positive birefringence; And a styrene-maleic acid-ester (SMA) resin having negative birefringence, and an ethylcellulose resin having the positive birefringence: styrene-maleic acid-ester (SMA) resin having a negative birefringence is 70: It may satisfy the range of 30 to 30:70, preferably 60:40 to 40:60.

The retardation film composition according to the present invention includes an ethyl cellulose resin having a positive birefringence; And a styrene-maleic acid-ester (SMA) resin having negative birefringence, and an ethylcellulose resin having the positive birefringence: styrene-maleic acid-ester (SMA) resin having a negative birefringence is 70: By satisfying 30 to 30:70, it has a characteristic capable of implementing a specific reverse wavelength dispersion by changing the wavelength dispersion.

In the exemplary embodiment of the present application, the positive birefringence and the negative birefringence mean a case in which the following conditions are satisfied in Equations A to C below.

[Equation A]

R _in =(n _x -n _y ) xd

[Equation B]

R _th =(n _z -(n _x +n _y )/2) xd

[Equation C]

N _z =(n _x -n _z )/(n _x -n _y )

In the above formulas A to C,

The n _x is the refractive index of the retardation film surface in the slow axis direction,

The n _y is a refractive index in the fast axis direction of the retardation film surface,

Wherein n _z is a refractive index in the thickness direction of the retardation film,

D is the thickness of the retardation film.

In the exemplary embodiment of the present application, the positive birefringence means a case in which any one of the following conditions 1 to 3 is satisfied.

1) Condition 1

n _x > n _y = n _z

R _in > 0

R _th > 0

N _z = 1.0

2) Condition 2

n _x > n _y > n _z

R _in > 0

R _th > 0

N _z > 1.0

3) Condition 3

n _z <n _y ≤ n _x

R _in > 0

R _th > 0

N _z ≫ 1.0

In the exemplary embodiment of the present application, the negative birefringence means a case in which any one of the following conditions 1 to 3 is satisfied.

1) Condition 1

n _y <n _x = n _z

R _in > 0

R _th <0

N _z = 0.0

2) Condition 2

n _y <n _x <n _z

R _in > 0

R _th > 0

N _z <0.0

3) Condition 3

n _y ≤ n _x <n _z

R _in > 0

R _th <0

N _z ≪ 0.0

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

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

In the exemplary embodiment of the present application, the weight average molecular weight of the styrene-maleic acid-ester (SMA) resin having negative birefringence may be 80,000 g/mol or more.

In another embodiment, the weight average molecular weight of the styrene-maleic acid-ester (SMA) resin having negative birefringence is 80,000 g/mol or more, preferably 90,000 g/mol or more, more preferably May be greater than or equal to 100,000 g/mol.

In another embodiment, the weight average molecular weight of the styrene-maleic acid-ester (SMA) resin having negative birefringence is 250,000 g/mol or less, preferably 200,000 g/mol or less, more preferably May be less than 180,000 g/mol.

In another embodiment, the weight average molecular weight of the styrene-maleic acid-ester (SMA) resin having negative birefringence is 80,000 g/mol or more and 250,000 g/mol or less, preferably 80,000 g/ mol or more and 200,000 g/mol or less, more preferably 100,000 g/mol or more and 180,000 g/mol or less.

The retardation film composition according to the present application is for implementing a specific reverse wavelength dispersion when a retardation film is formed later, and the styrene-maleic acid-ester (SMA) resin having negative birefringence is 30 parts by weight or more. It should be included, and accordingly, as the weight average molecular weight of the negative birefringence styrene-maleic acid-ester (SMA) resin included in the retardation film composition according to the present application is formed within the above range, a retardation film is formed later. It has a feature that does not cause a problem of film formation.

In the exemplary embodiment of the present application, the weight average molecular weight of the ethyl cellulose resin having the positive birefringence is 50,000 g/mol or more to provide a retardation film composition.

In another exemplary embodiment, the weight average molecular weight of the ethylcellulose resin having the positive birefringence is 50,000 g/mol or more and 310,000 g/mol or less.

In another exemplary embodiment, the weight average molecular weight of the ethylcellulose resin having positive birefringence is 50,000 g/mol or more, 310,000 g/mol or less, preferably 70,000 g/mol or more, 230,000 g/ mol or less, more preferably 100,000 g/mol or more, and 200,000 g/mol or less.

In an exemplary embodiment of the present application, a retardation film composition is provided in which the styrene content is 50 parts by weight or more based on 100 parts by weight of the styrene-maleic acid-ester (SMA) resin.

In another exemplary embodiment, the styrene content based on 100 parts by weight of the styrene-maleic acid-ester (SMA) resin may be 50 parts by weight or more and 90 parts by weight or less.

In another exemplary embodiment, the styrene content based on 100 parts by weight of the styrene-maleic acid-ester (SMA) resin is 50 parts by weight or more, 90 parts by weight or less, preferably 50 parts by weight or more, 85 It may be not more than 55 parts by weight, more preferably not more than 55 parts by weight, and not more than 80 parts by weight.

In the composition of the styrene-maleic acid-ester (SMA) resin, as the styrene content satisfies the above range, styrene-maleic acid-ester (SMA) included in the retardation film composition of the present application ) The content of the resin and the weight average molecular weight can be adjusted, and the retardation film thus prepared has a characteristic of having a specific reverse wavelength dispersion property.

In the exemplary embodiment of the present application, the styrene-maleic acid-ester (SMA) resin is a styrene-maleic anhydride-based copolymer (SMAh) subjected to a ring-opening reaction with alcohol or water, and the styrene-maleic acid- The ester (SMA) may have a carboxyl acid functional group.

In the exemplary embodiment of the present application, the retardation film composition uses a styrene-maleic acid-ester (SMA) resin in which a styrene-maleic anhydride-based copolymer (SMAh) is subjected to a ring-opening reaction with alcohol or water. If a ren-maleic anhydride-based copolymer (SMAh) is used, turbidity increases rapidly after the mixing, coating, or stretching process of the resin depending on the content, so that it cannot serve as a retardation film. Accordingly, the retardation film composition according to the present application Using a styrene-maleic acid-ester (SMA) resin, the above problem could be solved, and the desired wavelength dispersion property could be obtained.

In the exemplary embodiment of the present application, the retardation film composition comprises at least one selected from the group consisting of a solvent, a dispersant, an antioxidant, an adhesion promoter, a photoinitiator, a thermal initiator, a crosslinking agent, and a tackifier. to provide.

Particularly, when the retardation film composition further includes an antioxidant, the retardation film including the retardation film may have a characteristic in which durability of the retardation film including the same may be improved in the future.

In the exemplary embodiment of the present application, the crosslinking agent may include a crosslinkable compound, and the crosslinking agent may use an isocyanate-based crosslinking agent, and those known in the art may be used.

According to an exemplary embodiment of the present specification, the crosslinkable compound is hexanediol di (meth) acrylate, ethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate having 2 to 14 ethylene groups, trimethyl Allpropane di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, 2-trisacryloyloxymethylethylphthalic acid, propylene group Acidic modifications of propylene glycol di(meth)acrylate, dipentaerythritol penta(meth)acrylate, dipentaerythritol hexa(meth)acrylate, dipentaerythritol penta(meth)acrylate, and di Compounds obtained by esterifying polyhydric alcohols such as a mixture of pentaerythritol hexa(meth)acrylate (to-2348, TO-2349, manufactured by Dong-A Synthetic Japan as a brand name) with αβ-unsaturated carboxylic acid; Compounds obtained by adding (meth)acrylic acid to a compound containing a glycidyl group such as trimethylolpropane triglycidyl ether acrylic acid adduct and bisphenol A diglycidyl ether acrylic acid adduct; An ester compound of a compound having a hydroxyl group or ethylenically unsaturated bond, such as a phthalic acid diester of β-hydroxyethyl (meth)acrylate and a toluene diisocyanate adduct of β-hydroxyethyl (meth)acrylate, and a polyhydric carboxylic acid , Or adducts with polyisocyanates; (Meth)acrylic acid alkyl esters such as methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate; And 9,9'-bis[4-(2-acryloyloxyethoxy)phenyl]fluorene, and is not limited thereto and known in the art. You can use common ones.

According to an exemplary embodiment of the present specification, the photoinitiator is a triazine-based compound, a biimidazole compound, an acetophenone-based compound, an O-acyloxime-based compound, a thioxanthone-based compound, a phosphine oxide-based compound, a coumarin-based compound, and benzope. It may be substituted with one or two or more substituents selected from the group consisting of non-based compounds.

Specifically, according to the exemplary embodiment of the present specification, the photoinitiator is 2,4-trichloromethyl-(4'-methoxyphenyl)-6-triazine, 2,4-trichloromethyl-(4'-me Toxystyryl)-6-triazine, 2,4-trichloromethyl-(pipelonyl)-6-triazine, 2,4-trichloromethyl-(3',4'-dimethoxyphenyl)-6 -Triazine, 3-{4-[2,4-bis(trichloromethyl)-s-triazine-6-yl]phenylthio}propanoic acid, 2,4-trichloromethyl-(4'-ethyl ratio Triazine compounds such as phenyl)-6-triazine or 2,4-trichloromethyl-(4'-methylbiphenyl)-6-triazine; 2,2'-bis(2-chlorophenyl)-4,4',5,5'-tetraphenyl biimidazole or 2,2'-bis(2,3-dichlorophenyl)-4,4',5 Biimidazole-based compounds such as ,5'-tetraphenylbiimidazole; 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1-(4-isopropylphenyl)-2-hydroxy-2-methylpropan-1-one, 4-(2-hydroxye Oxy)-phenyl (2-hydroxy) propyl ketone, 1-hydroxycyclohexyl phenyl ketone, 2,2-dimethoxy-2-phenyl acetophenone, 2-methyl-(4-methylthiophenyl)-2-mol Acetopes such as polyno-1-propan-1-one (Irgacure-907) or 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)-butan-1-one (Irgacure-369) Non-based compounds; O-acyloxime compounds such as Irgacure OXE 01 and Irgacure OXE 02 of Ciba Geigy; Benzophenone compounds such as 4,4'-bis(dimethylamino)benzophenone or 4,4'-bis(diethylamino)benzophenone; Thioxanthone compounds such as 2,4-diethyl thioxanthone, 2-chloro thioxanthone, isopropyl thioxanthone, or diisopropyl thioxanthone; 2,4,6-trimethylbenzoyl diphenylphosphine oxide, bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentyl phosphine oxide or bis(2,6-dichlorobenzoyl) propyl phosphine oxide Phosphine oxide compounds such as; 3,3'-carbonylvinyl-7-(diethylamino)coumarin, 3-(2-benzothiazolyl)-7-(diethylamino)coumarin, 3-benzoyl-7-(diethylamino)coumarin, 3-benzoyl-7-methoxy-coumarin or 10,10'-carbonylbis[1,1,7,7-tetramethyl-2,3,6,7-tetrahydro-1H,5H,11H-Cl] Coumarin-based compounds such as -benzopyrano[6,7,8-ij]-quinolizin-11-one, etc. may be used alone or in combination of two or more, but are not limited thereto.

In addition, the thermal initiator may use those known in the art.

Usable solvents include alcohol solvents such as methanol, ethanol, isopropyl alcohol, butanol, alkoxy alcohol solvents such as 2-methoxyethanol, 2-ethoxyethanol, and 1-methoxy-2-propanol, acetone, Ketone solvents such as methyl ethyl ketone, methyl isobutyl ketone, methyl propyl ketone, and cyclohexanone, propylene glycol monopropyl ether, propylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether , Diethylene glycol monomethyl ether, diethyl glycol monoethyl ether, diethyl glycol monopropyl ether, diethyl glycol monobutyl ether, ether solvents such as diethylene glycol-2-ethylhexyl ether, benzene, toluene, xylene Aromatic solvents such as those described above may be used alone or in combination.

In an exemplary embodiment of the present application, a retardation film including a retardation film composition or a cured product thereof according to an exemplary embodiment of the present application is provided.

In the exemplary embodiment of the present application, the retardation film provides a retardation film that satisfies Equations 1 and 2 below.

[Equation 1]

0.5 <R _in (450)/R _in (550) <1.0

[Equation 2]

1.0 <R _in (650)/R _in (550) <1.2

In the above formulas 1 and 2,

R _in (λ) is the retardation in the plane direction at the wavelength λ nm, and is the value of _{(n x} -n _{y) xd,}

The n _x is the refractive index of the retardation film surface in the slow axis direction,

The n _y is a refractive index in the fast axis direction of the retardation film surface,

D is the thickness of the retardation film.

In Equations 1 and 2, R _in (λ) is a measurement of the phase difference in the plane direction at a wavelength of λnm, and the measurement is a value measured using Axoscan from Axometrics. That is, in Equation 1 and Equation 2, R _in (450), R _in (550) and R _in (650) refer to the plane direction retardation values at 450 nm, 550 nm and 650 nm, respectively.

The retardation in the plane direction at each wavelength is a value determined by 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 1 and 2 above. to be. The slow axis and fast axis are determined according to the orientation direction of the polymer chain of the retardation film, and the direction in which the polymer chain is aligned is called the slow axis. The direction in which the phase difference delay is greatest because it takes a long time for light to pass is called the slow axis. The fast axis is the opposite concept, and the direction in which the orientation of the polymer chain becomes smaller is called the fast axis, which takes a short time for light to pass through at each wavelength, and the direction with the smallest retardation is advanced. It is called the Fast Axis.

In Equation 1, the retardation in the plane direction at a wavelength of _{550 nm may be referred to as R in} (550), and the retardation in the plane direction at a wavelength of 450 nm may be referred to _{as R in (450).} When the retardation ratio R _in (450)/R _in (550) at the two wavelengths is less than 1, it is called reverse wavelength dispersion. When it is 1, the flat (flat) wavelength is dispersed. Represents.

_{As in} Equation 1, when R in (650)/R _in (550) has the range of Equation 2, it can be seen that the equation 2 represents a reverse wavelength dispersion.

In addition, in the exemplary embodiment of the present application, the retardation film provides a retardation film that satisfies Equations 3 and 4 below.

[Equation 3]

20nm ≤ R _in (550) ≤ 300nm

[Equation 4]

-300nm ≤ R _th (550) ≤ 0nm

In the above formulas 3 and 4,

R _in (550) is the retardation in the plane direction at a wavelength of 550 nm, and is a value of _{(n x} -n _{y) xd,}

R _th (550) is the retardation in the thickness direction at a wavelength of 550 nm, and is a value of {n _z -(n _x +n _y )/2} xd,

The n _x is the refractive index of the retardation film surface in the slow axis direction,

The n _y is a refractive index in the fast axis direction of the retardation film surface,

Wherein n _z is a refractive index in the thickness direction of the retardation film,

D is the thickness of the retardation film.

In Equation 3 and Equation 4, R _in (λ) is a measure of the phase difference in the plane direction at a wavelength of λnm, and the measurement is a value measured using Axoscan of Axometrics. In addition, R _th (λ) is a retardation in the thickness direction at a wavelength of λ nm, and is a value determined by a value of the difference from the average of the refractive indexes in the plane direction and the thickness by measuring the refractive index in the thickness direction with an AxoScan device.

In the exemplary embodiment of the present application, the thickness of the retardation film is 5 μm or more and 500 μm It may be below.

In another exemplary embodiment, the thickness of the retardation film is 5 μm or more and 500 μm Or less, preferably 15 µm or more and 300 µm Or less, more preferably 15 µm or more and 50 µm It can be below.

As can be seen from Equations 1 to 4, the retardation value changes according to 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 reverse wavelength dispersion, and is included in the liquid crystal display device later. If so, it has features that can increase the size and durability of the liquid crystal display device in a suitable thickness range.

In the exemplary embodiment of the present application, the solvent included in the retardation film composition may be removed from the retardation film by drying or curing the composition.

On the other hand, the manufacturing method of the retardation film of the present invention having the above characteristics is not particularly limited, it may be produced by a method of forming a film after preparing the composition, and stretching it.

The composition is prepared by extruding and kneading the obtained mixture after pre-blending the film raw material with any suitable mixer such as an omni mixer. In this case, the mixer used for extrusion and kneading is not particularly limited, and for example, an extruder such as a single screw extruder and a twin screw extruder, or any suitable mixer such as a pressure kneader can be used.

As the method of forming the film, any suitable film forming method such as a solution casting method (solution casting method), a melt extrusion method, a calender method, and a compression molding method may be mentioned. Among these film forming methods, a solution casting method (solution casting method) and a melt extrusion method are preferable.

The solvent used in the solution casting method (solution casting method) includes, for example, aromatic hydrocarbons such as benzene, toluene, and xylene; Aliphatic hydrocarbons such as cyclohexane and decalin; Esters such as ethyl acetate and butyl acetate; Ketones such as acetone, methyl ethyl ketone, and methyl isobutyl ketone; Alcohols such as methanol, ethanol, isopropanol, butanol, isobutanol, methyl cellosolve, ethyl cellosolve, and butyl cellosolve; Ethers such as tetrahydrofuran and dioxane; Halogenated hydrocarbons such as dichloromethane, chloroform, and carbon tetrachloride; Dimethylformamide; And dimethyl sulfoxide. These solvents may be used alone or in combination of two or more.

As an apparatus for performing the solution casting method (solution casting method), for example, a drum type casting machine, a band type casting machine, a spin coater, and the like may be mentioned. On the other hand, examples of the melt extrusion method include a T-die method and an inflation method. The molding temperature may be 150°C to 350°C, or 200°C to 300°C.

In the case of forming a film by the T-die method, a T-die is attached to the tip of a known single-screw extruder or twin-screw extruder, and the extruded film is wound up to obtain a roll-shaped film.

After the film is formed through the above process, the film is stretched. In the stretching process, stretching in the longitudinal direction (MD) and stretching in the transverse direction (TD) may be performed, respectively, or both may be performed. Further, in the case of performing both longitudinal stretching and transverse stretching, either one may be first stretched and then stretched in the other direction, or both directions may be simultaneously stretched. In addition, the stretching may be performed in one step or may be performed in multiple steps. In the case of stretching in the longitudinal direction, stretching may be performed by a difference in speed between the rolls, and in the case of stretching in the transverse direction, a tenter may be used. The starting angle of the tenter's rail is usually within 10 degrees, thereby suppressing the bowing phenomenon occurring at the time of stretching in the lateral direction, and controlling the angle of the optical axis regularly. Even when the transverse stretching is carried out in multiple stages, a bowing suppression effect can be obtained.

The stretching temperature is preferably in a range near the glass transition temperature of the composition as a raw material for the film, and when the glass transition temperature of the composition is Tg, preferably (Tg-30°C) to (Tg+100°C), more It is preferably in the range of (Tg-20°C) to (Tg+80°C), more preferably (Tg-5°C) to (Tg+20°C). If the stretching temperature is less than (Tg-30°C), there is a concern that a sufficient stretching ratio may not be obtained. Conversely, when the stretching temperature exceeds (Tg+100°C), flow (flow) of the resin composition occurs, and there is a fear that stable stretching may not be performed.

In addition, in the exemplary embodiment of the present application, the stretching ratio in the step of stretching the film may be 1.05 to 10 times the length in the stretching direction.

In addition, the total stretch ratio may be stretched to be 1.1 times or more, 1.2 times or more, or 1.5 times or more, 25 times or less, or 10 times or less, or 7 times or less based on the total stretched area of the base film. When the stretching ratio is less than 1.1 times, the effect of stretching may not be sufficiently achieved, and when it exceeds 25 times, the film layer may be cracked.

Before the stretching, a process of flattening the coated surface of the composition and drying to volatilize the solvent contained in the composition may be further performed.

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 heat treatment conditions are not particularly limited, and any suitable conditions known to those skilled in the art may 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 an exemplary embodiment of the present invention, a polarizer; And it provides a polarizing plate including at least one or more retardation film of the present application.

1 is a diagram showing a stacked structure of a 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 retardation film 101 are stacked on one surface of the polarizer.

In the exemplary 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 a dichroic dye is used.

The polarizer vibrates in various directions and exhibits a characteristic of extracting only light vibrating in one direction from incident light. This property can be achieved by stretching iodine-absorbed poly vinyl alcohol (PVA) with strong tension. For example, more specifically, swelling of swelling by immersing a PVA film in an aqueous solution, dyeing with a dichroic material imparting 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 materials side by side in a stretching direction, and a complementary color step of correcting the color of the PVA film after the stretching step. However, the polarizing plate of the present invention is not limited thereto.

In the exemplary embodiment of the present application, the polarizer and the retardation film may be bonded with an adhesive, and the adhesive that can be used is not particularly limited as long as it is known in the art. For example, there are water-based adhesives, one- 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. 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 on the protective film of the conventional polarizing plate to which the protective film is attached to both sides of the polarizer, and may be usefully used as a retardation film.

When the retardation film is directly attached to one or both sides of a polarizer, for example, the structure may be an upper protective film/polarizer/phase difference film or a retardation film/polarizer/lower protective film. The attachment method is after coating a primer on the surface of a retardation film or polarizer using a roll coater, gravure coater, bar coater, knife coater, capillary coater, or micro chamber doctor blade coater. , Spraying the adhesive in a dropping method, and heat-laminating the laminate including the retardation film and the polarizer with a laminating roll, a method of laminating by pressing at room temperature, or a method of UV curing.

2 is a diagram showing a stacked 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 a polarizer protective film 104 / an adhesive layer 105 / a phase difference film 101 / a polarizer 102 / a 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 is attached of the polarizer. do.

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

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

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

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

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

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

The lower polarizing plate includes the polarizer; And the retardation film, wherein the retardation film is disposed to face the backlight unit, wherein the lower polarizing plate comprises the polarizer; And the phase difference film, wherein the phase difference film is disposed in the direction of the backlight unit in the liquid crystal display device, and specifically, the backlight unit/polarizer/phase difference film/liquid crystal cell/upper polarizing plate are sequentially stacked. It means to have a structure.

In the liquid crystal display device according to the present application, when the retardation film of the upper polarizing plate is disposed to face the liquid crystal cell, or the retardation film of the lower polarizing plate is disposed to face the backlight unit, it is included in the retardation film. The triazine-based birefringence modifier may have a main purpose in improving the function of the panel by a function of expressing a phase difference rather than an ultraviolet absorption function.

In the present invention, the terms "top" and "upper" mean a surface or direction arranged to face the viewer, that is, the viewer, when the polarizing plate is mounted on a device such as a liquid crystal display. Conversely, when the polarizing plate is mounted on the device, the'lower side' and the'lower side' refer to a surface or a direction arranged to face the viewer opposite, that is, the backlight unit.

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 may be used.

3 is a diagram illustrating a liquid crystal display 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 of the lower polarizing plate 12 adjacent to the backlight unit 14 and in contact with the liquid crystal cell 10 It may have a structure in which the protective film 13 is 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.

In an exemplary embodiment of the present application, an organic light emitting device (OLED) panel; And an upper polarizing plate provided on the organic light emitting element (OLED) panel, wherein the upper polarizing plate includes a polarizer; And it is intended to provide an organic light-emitting device (OLED) display including the retardation film according to the present application disposed on one surface of the polarizer.

The organic light-emitting device (OLED) display including the retardation film according to the present application has excellent anti-reflection properties not only in the front direction of the screen, but also in the oblique direction.

4 illustrates a schematic stacking structure of an organic light emitting diode (OLED) display according to the present application, and the stacking order of the polarizer and the retardation film may be changed according to the use.

In the exemplary embodiment of the present application, the structure of the organic light-emitting device (OLED) display is not particularly limited, and any known structure may be employed. Since these structures are well known in the art, detailed descriptions thereof will be omitted.

Typically, in the organic light emitting diode (OLED) display, an anode and a cathode are stacked on a substrate, and at least one organic thin film layer may be provided between the anode and the cathode, and the organic thin film layer may be red or green. Green) and a light emitting layer for implementing the colors of blue may be included, and in addition, at least one of a hole injection layer, a hole transport layer, an electron injection layer, and an electron transport layer may be included.

In the exemplary embodiment of the present application, the emission layer may include a host and a dopant.

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

< Example >

1) Example 1

Poly(styrene-co-maleic acid), partial butyl/methyl mixed ester, Solenis Scripset 540 3g and DOW ETHOCEL ^TM After dissolving 7 g of Standard 100 in 66.9 g of ethyl acetate, a transparent solution was prepared by additional stirring of 0.1 phr compared to 100 of the resin solid content in which AO-60 was previously dissolved. At this time, Scripset 540 has a weight average molecular weight of 180,000 g/mol and a styrene content of 55%. After preparing the polymer solution, it was cast on a 100um PET film (SKC) to a certain thickness using an applicator, dried in a 50°C drying oven for 5 minutes, and then dried in a 110°C drying oven for 10 minutes. After peeling the dried coating film from the PET film, it was uniaxially stretched 1.5 times at a temperature of 150° C. with a Lab stretcher, and the thickness and phase difference were measured, and are shown in Tables 1 and 2 below.

2) Example 2

After dissolving 6g of Solenis Scripset 540 and ^{4g of DOW's ETHOCEL TM} Standard 100 in 66.9g of ethyl acetate (Ethyl acetate), a transparent solution was prepared by additional agitation of 0.1 phr compared to 100 of the resin solid content in which AO-60 was previously dissolved. After preparing the polymer solution, it was cast on a 100um PET film (SKC) to a certain thickness using an applicator, dried in a 50°C drying oven for 5 minutes, and then dried in a 110°C drying oven for 10 minutes. After peeling the dried coating film from the PET film, it was uniaxially stretched 1.5 times at a temperature of 155° C. with a Lab stretcher, and the thickness and phase difference were measured and shown in Tables 1 and 2 below.

3) Example 3

Poly(styrene-co-maleic acid), a partial secondary butyl ester, Solenis Scripset 550 3g and DOW ETHOCEL ^TM Standard 100 7g Ethyl Acetate After dissolving in 66.9 g of acetate), a transparent solution was prepared by performing additional stirring of 0.1 phr compared to 100 of the resin solid content in which AO-60 was previously dissolved. At this time, Scripset 550 has a weight average molecular weight of 105,000 g/mol and a styrene content of 59%. After preparing the polymer solution, it was cast on a 100um PET film (SKC) to a certain thickness using an applicator, dried in a 50°C drying oven for 5 minutes, and then dried in a 110°C drying oven for 10 minutes. After peeling the dried coating film from the PET film, it was uniaxially stretched 1.5 times at a temperature of 150° C. with a Lab stretcher, and the thickness and phase difference were measured, and are shown in Tables 1 and 2 below.

4) Example 4

After dissolving 6g of Solenis Scripset 550 and ^{4g of DOW's ETHOCEL TM} Standard 100 in 66.9 g of Ethyl acetate, a transparent solution was prepared by additional stirring of 0.1 phr compared to 100 of the resin solid content in which AO-60 was previously dissolved. After preparing the polymer solution, it was cast on a 100um PET film (SKC) to a certain thickness using an applicator, dried in a 50°C drying oven for 5 minutes, and then dried in a 110°C drying oven for 10 minutes. After peeling the dried coating film from the PET film, it was uniaxially stretched 1.5 times at a temperature of 160° C. with a Lab stretcher, and the thickness and phase difference were measured and shown in Tables 1 and 2 below.

5) Example 5

A retardation film was prepared in the same manner as in Example 4, except that the draw ratio was 2.0 times, and the thickness and retardation were measured, and are shown in Tables 1 and 2 below.

6) Example 6

After dissolving 7 g of Solenis Scripset 550 and ^{3 g of DOW ETHOCEL TM} Standard 100 in 66.9 g of Ethyl acetate, a transparent solution was prepared by additional stirring of 0.1 phr compared to 100 of the resin solid content in which AO-60 was previously dissolved. After preparing the polymer solution, it was cast on a 100um PET film (SKC) to a certain thickness using an applicator, dried in a 50°C drying oven for 5 minutes, and then dried in a 110°C bath oven for 10 minutes. After peeling the dried coating film from the PET film, it was uniaxially stretched 1.5 times at a temperature of 165° C. with a Lab stretcher, and the thickness and phase difference were measured and shown in Tables 1 and 2 below.

7) Comparative Example 1

After dissolving 10 g of DOW's ETHOCEL ^TM Standard 100 in 80 g of Ethyl acetate, a transparent solution was prepared by additional stirring of 0.1 phr compared to 100 of the resin solid content in which AO-60 was previously dissolved. After preparing the polymer solution, it was cast on a 100um PET film (SKC) to a certain thickness using an applicator, dried in a 50°C drying oven for 5 minutes, and then dried in a 110°C bath oven for 10 minutes. After peeling the dried coating film from the PET film, it was uniaxially stretched 1.5 times at a temperature of 145° C. with a Lab stretcher, and the thickness and phase difference were measured and shown in Tables 1 and 2 below.

8) Comparative Example 2

2 g of Scripset 540 from Solenis and ^{8 g of ETHOCEL TM} Standard 100 from DOW were dissolved in 66.9 g of Ethyl acetate, followed by additional agitation of 0.1 phr compared to 100 solids of the resin previously dissolved in AO-60 to prepare a transparent solution. After preparing the polymer solution, it was cast on a 100um PET film (SKC) to a certain thickness using an applicator, dried in a 50°C drying oven for 5 minutes, and then dried in a 110°C drying oven for 10 minutes. After peeling the dried coating film from the PET film, it was uniaxially stretched 1.5 times at a temperature of 150° C. with a Lab stretcher, and the thickness and phase difference were measured, and are shown in Tables 1 and 2 below.

9) Comparative Example 3

^{After dissolving 2g of Solenis Scripset 520 and 8g of DOW's ETHOCEL TM} Standard 100, which is styrene maleic anhydride, in 66.9g of Ethyl acetate, add 0.1phr to 100% resin solid content dissolved in AO-60 to be transparent. The solution was prepared. At this time, Scripset 520 has a weight average molecular weight of 350,000g/mol and a Styrene content of 50%. After preparing the polymer solution, it was cast on a 100um PET film (SKC) to a certain thickness using an applicator, dried in a 50°C drying oven for 5 minutes, and then dried in a 110°C drying oven for 10 minutes. After peeling the dried coating film from the PET film, it was confirmed that the phase was separated and the film was not formed.

10) Comparative Example 4

After dissolving 6g of product name 435287 of Sigma aldrich, which is a poly(styrene-co-maleic acid) partial isobutyl ester, and ^{4g of DOW's ETHOCEL TM} Standard 100, in 66.9g of Ethyl acetate, 0.1 compared to 100 solids of the resin previously dissolved in AO-60. Further stirring was performed to prepare a clear solution. At this time, 435287 has a weight average molecular weight of 78,000 g/mol and a Styrene content of 50%. After preparing the polymer solution, it was cast on a 100um PET film (SKC) to a certain thickness using an applicator, dried in a 50°C drying oven for 5 minutes, and then dried in a 110°C drying oven for 10 minutes. When looking at the dried coating film, it was confirmed that the film was phase-separated and brittle, so that the film could not be formed.

Resin 1 ratio
(%) Suzy 2 ratio
(%) Stretching temperature
(℃) Draw ratio
(x) Film thickness
(μm) Comparative Example 1 - - ETHOCEL ^TM Standard 100 100 145 1.5 10.1 Comparative Example 2 Scripset 540 20 ETHOCEL ^TM Standard 100 80 150 1.5 21.5 Comparative Example 3 Scripset 520 20 ETHOCEL ^TM Standard 100 80 - - - Comparative Example 4 435287 60 ETHOCEL ^TM Standard 100 40 - - - Example 1 Scripset 540 30 ETHOCEL ^TM Standard 100 70 150 1.5 18.4 Example 2 Scripset 540 60 ETHOCEL ^TM Standard 100 40 155 1.5 77.1 Example 3 Scripset 550 30 ETHOCEL ^TM Standard 100 70 150 1.5 23.3 Example 4 Scripset 550 60 ETHOCEL ^TM Standard 100 40 160 1.5 61.2 Example 5 Scripset 550 60 ETHOCEL ^TM Standard 100 40 165 2.0 66.6 Example 6 Scripset 550 70 ETHOCEL ^TM Standard 100 30 165 1.5 91.6

Rin(550)nm Rth(550)nm Rin(450)/Rin(550) Rin(650)/Rin(550) Comparative Example 1 151.3 -96.7 1.01 0.99 Comparative Example 2 190.9 -135.6 1.01 1.00 Comparative Example 3 - - - - Comparative Example 4 - - - - Example 1 128.6 -79.7 0.99 1.01 Example 2 118.9 -78.7 0.94 1.03 Example 3 174.5 -104.9 0.99 1.01 Example 4 120.6 -73.5 0.93 1.03 Example 5 143.7 -72.0 0.95 1.02 Example 6 55.6 -36.4 0.88 1.07

As can be seen from Tables 1 and 2, the retardation film composition according to the present invention includes an ethylcellulose resin having positive birefringence; And a styrene-maleic acid-ester (SMA) resin having negative birefringence, and an ethylcellulose resin having the positive birefringence: styrene-maleic acid-ester (SMA) resin having a negative birefringence is 70: By satisfying 30 to 30:70, it was confirmed that it has a characteristic capable of implementing a specific reverse wavelength dispersion by changing the wavelength dispersion.

In order to implement a specific reverse wavelength dispersion as described above, the styrene-maleic acid-ester (SMA) resin having negative birefringence should contain 30 parts by weight or more, and accordingly, in the retardation film composition according to the present application The weight average molecular weight of the included styrene-maleic acid-ester (SMA) resin having negative birefringence is 80,000 g/mol or more, so that film formation problems do not occur when forming a retardation film in the future. I could confirm.

In Comparative Example 1 of Tables 1 and 2, it was confirmed that the styrene-maleic acid-ester resin having negative birefringence was not used, and that the desired wavelength dispersion was not realized, and Tables 1 and 2 In Comparative Example 2 of, it was confirmed that the desired wavelength dispersion was not implemented as a case where the weight part of the styrene-maleic acid-ester (SMA) resin having negative birefringence was not more than 30 parts by weight as 20 parts by weight. there was.

Solenis Scripset 520, which is the styrene maleic anhydride used in Comparative Example 3 of Tables 1 and 2, used maleic anhydride, not maleic acid ester, and mixed with ethyl cellulose such as maleic acid ester. It could be confirmed that the film was not formed, showing no properties, showing phase separation after coating.

Sigma aldrich 435287, a poly(styrene-co-maleic acid) partial isobutyl ester used in Comparative Example 4 of Tables 1 and 2, has a weight average molecular weight of 78,000 g/mol, and due to its low molecular weight, sufficient strength of the film It was confirmed that it was not filmed because it did not have a stalk and was brittle and broken.

101: retardation film
102: polarizer
103: polarizing plate
104: polarizer protective film
105: adhesive layer
10: liquid crystal cell
11: upper polarizer
12: lower polarizer
13: protective film
14: backlight unit
15: organic light emitting element panel
16: organic light emitting device display

Claims (14)

Ethylcellulose resin having positive birefringence; And
Styrene-maleic acid-ester (SMA) resin having negative birefringence;
As a retardation film composition comprising a,
The weight average molecular weight of the styrene-maleic acid-ester (SMA) resin having negative birefringence is 80,000 g/mol or more,
The ethyl cellulose resin having the positive birefringence: a phase difference film composition in which the styrene-maleic acid-ester (SMA) resin having negative birefringence satisfies 70:30 to 30:70. The method according to claim 1,
The phase difference film composition in which the styrene content is 50 parts by weight or more based on 100 parts by weight of the styrene-maleic acid-ester (SMA) resin. The method according to claim 1,
The weight average molecular weight of the ethyl cellulose resin having the positive birefringence is 50,000 g/mol or more. The method according to claim 1,
The retardation film composition comprising at least one selected from the group consisting of a solvent, a dispersant, an antioxidant, an adhesion promoter, a photoinitiator, a thermal initiator, a crosslinking agent, and a tackifier. A retardation film comprising the retardation film composition of any one of claims 1 to 4 or a cured product thereof. The method of claim 5,
The retardation film is a retardation film that satisfies the following Equations 1 and 2:
[Equation 1]
0.5 <R _in (450)/R _in (550) <1.0
[Equation 2]
1.0 <R _in (650)/R _in (550) <1.2
In the above formulas 1 and 2,
R _in (λ) is the phase difference in the plane direction at the wavelength λ nm, and is the value of _{(n x} -n _{y) xd,}
The n _x is the refractive index of the retardation film surface in the slow axis direction,
The n _y is a refractive index in the fast axis direction of the retardation film surface,
D is the thickness of the retardation film. The method of claim 5,
The retardation film is a retardation film that satisfies the following Equation 3 and Equation 4:
[Equation 3]
20nm ≤ R _in (550) ≤ 300nm
[Equation 4]
-300nm ≤ R _th (550) ≤ 0nm
In the above formulas 3 and 4,
R _in (550) is the retardation in the plane direction at a wavelength of 550 nm, and is a value of _{(n x} -n _{y) xd,}
R _th (550) is the retardation in the thickness direction at a wavelength of 550 nm, and is a value of {n _z -(n _x +n _y )/2} xd,
The n _x is the refractive index of the retardation film surface in the slow axis direction,
The n _y is a refractive index in the fast axis direction of the retardation film surface,
Wherein n _z is a refractive index in the thickness direction of the retardation film,
D is the thickness of the retardation film. The method of claim 5,
The thickness of the retardation film is 5 μm or more and 500 μm The retardation film which is the following. Polarizer; And
A polarizing plate comprising at least one or more retardation films of claim 5. The method of claim 9,
A polarizer protective film is attached to one side of the polarizer,
The polarizing plate that the retardation film is attached to the opposite surface of the polarizer protective film is attached to the surface of the polarizer. Liquid crystal cell;
An upper polarizing plate provided on the upper layer of the liquid crystal cell;
A lower polarizing plate provided on the lower layer of the liquid crystal cell; And
Including a backlight unit provided in 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 claim 5 disposed on one surface of the polarizer. The method of claim 11,
The upper polarizing plate includes the polarizer; And the retardation film,
The phase difference film is a liquid crystal display device that is disposed so as to face the liquid crystal cell. The method of claim 11,
The lower polarizing plate includes the polarizer; And the retardation film,
The phase difference film is a liquid crystal display device that is disposed so as to face the backlight unit. Organic light-emitting device (OLED) panels; And
An upper polarizing plate provided on the organic light-emitting device (OLED) panel;
An organic light-emitting device (OLED) display comprising a,
The upper polarizing plate is a polarizer; And the retardation film of claim 5 disposed on one surface of the polarizer.

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