KR20170013143A - Optical film and display device - Google Patents

Abstract

The present invention relates to an optical film and a display device. The optical film includes a polarizing film which includes polyolefin and dichroic dye, a first phase delay layer which is located on one side of the polarizing film and includes a liquid crystal, a second phase delay layer which is located on one side of the first phase delay layer and includes a liquid crystal, a first adhesive which is located between the polarizing film and the first phase delay layer, and a second adhesive which is located between the first phase delay layer and the second phase delay layer. At least one of the first adhesive and the second adhesive has a room temperature storage modulus of 0.2 MPa or more in a 10 Hz frequency. Accordingly, the present invention can provide the optical film with a thin thickness and high durability.

Description

[0001] OPTICAL FILM AND DISPLAY DEVICE [0002]

An optical film and a display device.

A flat panel display device which is mainly used now can be divided into a light emitting display device which emits light by itself and a light receiving display device which requires a separate light source. Optical films such as compensation films are frequently used as a method for improving the image quality of these devices .

In the case of a light emitting display device such as an organic light emitting display, visibility and contrast ratio may be lowered due to reflection of external light by a metal such as an electrode. In order to reduce this, the polarizing plate and the phase difference film are used to convert the linearly polarized light into the circularly polarized light so that the external light reflected by the organic light emitting display does not leak out.

A liquid crystal display (LCD), which is a light-receiving type display device, is a method for resolving outside light reflection and sunglass effect according to types such as transmission type, transflective type, and reflection type, and converts linearly polarized light into circularly polarized light to improve image quality have.

However, currently developed optical films have poor durability, which can affect the display quality and can be particularly damaged in bending or folding. In addition, the thickness of the optical film itself is too thick, which is a hindrance to the thinness of the display device.

One embodiment provides an optical film that can realize a thin thickness while enhancing durability.

Another embodiment provides a display device comprising the optical film.

According to one embodiment, there is provided a polarizing element comprising a polarizing film comprising a polyolefin and a dichroic dye, a first retardation layer disposed on one side of the polarizing film and including a liquid crystal, a second retardation layer disposed on one side of the first retardation layer, A first adhesive disposed between the polarizing film and the first retardation layer and a second adhesive disposed between the first retardation layer and the second retardation layer, At least one of the pressure-sensitive adhesive and the second pressure-sensitive adhesive provides an optical film having a room temperature storage elastic modulus of 0.2 MPa or more at a frequency of 10 Hz.

The pressure-sensitive adhesive may be at least one selected from the group consisting of (meth) acrylic compounds, urethane compounds, polyisobutylene compounds, styrene butadiene rubber, polyvinyl ether compounds, epoxy compounds, melamine compounds, polyester compounds, phenol compounds, silicone compounds, Coalescence, or a combination thereof.

The pressure-sensitive adhesive may include a resin having a hydroxyl group, a carboxyl group, a nitrogen-containing functional group, or a combination thereof.

The pressure-sensitive adhesive may be a crosslinked resin using a crosslinking agent comprising an isocyanate compound, an epoxy compound, an aziridine compound, a metal chelate compound, or a combination thereof.

The first retardation layer and the second retardation layer may be thinner than the first adhesive or the second adhesive, respectively.

The thicknesses of the first retardation layer and the second retardation layer may be about 0.05 to 0.8 times the thickness of the first adhesive or the second adhesive, respectively.

The thicknesses of the first adhesive and the second adhesive may be about 5 탆 to 25 탆, respectively, and the thicknesses of the first retardation layer and the second retardation layer may be 0.5 탆 to 5 탆, respectively.

The thickness sum of the first retardation layer and the second retardation layer may be about 1 탆 to 10 탆.

At least one of the first pressure-sensitive adhesive and the second pressure-sensitive adhesive may have a room temperature storage elastic modulus of about 0.2 MPa to 8 GPa at a frequency of 10 Hz.

At least one of the first pressure sensitive adhesive and the second pressure sensitive adhesive may have a 180 DEG peel force at room temperature of about 1500 gf / 25 mm or more for the first phase retardation layer or the second phase retardation layer.

One of the first retardation layer and the second retardation layer may have an in-plane retardation of about 230 nm to 300 nm for a wavelength of 550 nm, and the other of the first retardation layer and the second retardation layer has a retardation The in-plane retardation for the wavelength may be about 110 nm to 160 nm.

The liquid crystal of the first phase delay layer and the liquid crystal of the second phase retardation layer may independently have a refractive index satisfying the following relational expression 1A or 1B.

[Relation 1A]

n _x > n _y = n _z

[Relation 1B]

n _x <n _y = n _z

In the above relational expressions 1A and 1B,

n _x is a refractive index at a slow axis between the first and second phase delay layers and n _y is a fast axis of the first and second phase delay layers, And n _z is the refractive index in the vertical direction to n _x and n _y .

The in-plane retardation (R _e1 ) of the first phase retardation layer with respect to the wavelengths of 450 nm, 550 nm and 650 nm can satisfy R _e1 (450 nm)> R _e1 (550 nm)> R _e1 (650 nm) wherein the in-plane retardation (R _e2) of the second phase delay layer on the _{R e2 (450nm)> R e2} (550nm)> R e2 may be satisfied (650nm), the first phase for 450nm, 550nm and 650nm wavelength overall in-plane retardation of the retardation layer and the second phase delay layer (R _e0) is _{R e0 (450nm) ≤R e0 (} 550nm) <R e0 (650nm) or _{R e0 (450nm) <R e0} (550nm) ≤R e0 (650 nm) can be satisfied.

The short wavelength dispersion of the first phase delay layer and the second phase retardation layer may be about 1.1 to 1.2 and the overall short wavelength dispersion of the first phase retardation layer and the second phase retardation layer may be about 0.70 to 0.99 have.

The long wavelength dispersion properties of the first phase delay layer and the second phase retardation layer may be about 0.9 to 1.0 and the entire long wavelength dispersion properties of the first phase retardation layer and the second phase retardation layer may be about 1.01 to 1.20 have.

The polarizing film may have a thickness of about 100 mu m or less.

According to another embodiment, there is provided a display device including a display panel and an optical film disposed on at least one side of the display panel.

The display panel may include a liquid crystal display panel or an organic light emitting display panel.

The display panel may be a flexible display panel.

By providing an optical film having a thin thickness and high durability, a thin display device having good display quality can be realized. Further, since the durability of the folded or bent portion is strong, it can be effectively applied to a flexible display device.

1 is a schematic cross-sectional view of an optical film according to one embodiment,
2 is a schematic view showing the principle of prevention of external reflection of the optical film,
FIG. 3 is a schematic cross-sectional view showing a polarizing film in the optical film of FIG. 1,
FIG. 4 is a cross-sectional view schematically illustrating an organic light emitting display according to an embodiment,
5 is a cross-sectional view schematically showing a liquid crystal display device according to one embodiment,
6 is an external view of the optical film according to Example 5 attached to the reflector after the bending test,
7 is an external view of an optical film according to Example 6 having a reflector after performing a bending test,
8 is an external view of an optical film according to Example 7 having a reflector after performing a bending test,
Fig. 9 is an external view of an optical film according to Comparative Example 1 to which a reflector is attached after performing a bending test. Fig.

Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily carry out the present invention. However, implementations may be implemented in various different forms and are not limited to the implementations described herein.

In the drawings, the thickness is enlarged to clearly represent the layers and regions. Like parts are designated with like reference numerals throughout the specification. Whenever a portion of a layer, film, region, plate, or the like is referred to as being "on" another portion, it includes not only the case where it is "directly on" another portion, but also the case where there is another portion in between. Conversely, when a part is "directly over" another part, it means that there is no other part in the middle.

Hereinafter, an optical film according to one embodiment will be described with reference to the drawings.

1 is a schematic cross-sectional view of an optical film according to one embodiment.

1, an optical film 300 according to an exemplary embodiment includes a polarizing film 110, a first retardation layer 120a, a second retardation layer 120b, a polarizing film 110, A first adhesive 115a positioned between the retardation layer 120a and a second adhesive 115b positioned between the first retardation layer 120a and the second retardation layer 120b.

The first phase delay layer 120a and the second phase delay layer 120b may have different in-plane retardations. For example, the first phase retardation layer 120a and the second phase retardation layer 120b may be formed with respect to a 550 nm wavelength One of the second phase delay layer 120b may have an in-plane retardation of about 230 nm to 300 nm and the other may have an in-plane retardation of about 110 nm to 160 nm. As an example, the in-plane retardation of the first retardation layer 120a with respect to the reference wavelength may be between about 230 nm and 300 nm, and the in-plane retardation of the second retardation layer 120b with respect to the reference wavelength may be between about 110 nm and 160 nm.

For example, one of the first retardation layer 120a and the second retardation layer 120b may be a lambda / 2 phase delay layer and the other may be a lambda / 4 phase retardation layer. For example, the first phase delay layer 120a may be a lambda / 2 phase delay layer and the second phase delay layer 120b may be a lambda / 4 phase delay layer.

The first and second retardation layers 120a and 120b can circularly polarize light passing through the polarizing film 110 to generate a retardation and affect reflection and / or absorption of light .

For example, the optical film 300 may be provided on one side or both sides of the display device, and in particular, may be disposed on the screen side of the display device to prevent reflection of light (hereinafter referred to as 'external light' . Therefore, deterioration of visibility due to reflection of external light can be prevented.

2 is a schematic view showing the principle of prevention of external light reflection of an optical film.

2, an incident unpolarized light is transmitted through the polarizing film 110 so that only one polarized quadrature component of the two polarized quadrature components, that is, the first polarized quadrature component, is transmitted, The light can be converted into circularly polarized light while passing through the first and second phase delay layers 120a and 120b. The circularly polarized light is reflected by the display panel 50 including the substrate, the electrodes, and the like, so that the circularly polarized light changes direction and the circularly polarized light passes through the second phase delay layer 120b and the first phase delay layer 120a Only the second polarization orthogonal component, that is, the second polarization orthogonal component, of the two polarization orthogonal components can be transmitted. Since the second polarized quadrature component does not pass through the polarizing film 110 and thus does not emit light to the outside, it can have an effect of preventing reflection of external light.

FIG. 3 is a schematic cross-sectional view showing a polarizing film in the optical film of FIG. 1;

3, the polarizing film 110 may be an integral stretched film made of a melt blend of a polyolefin 71 and a dichroic dye 72.

The polyolefin 71 may be, for example, a mixture of at least two selected from polyethylene (PE), polypropylene (PP), a copolymer of polyethylene and polypropylene (PE-PP), and examples thereof include polypropylene (PP) and polyethylene- Copolymer (PE-PP).

The polypropylene (PP) may have a melt flow index (MFI) of, for example, from about 0.1 g / 10 min to about 5 g / 10 min. Here, the melt flow index (MFI) represents the amount of polymer flowing in a molten state per 10 minutes, which is related to the viscosity of the molten polyolefin. That is, the lower the melt flow index (MFI), the higher the polyolefin viscosity and the higher the melt flow index (MFI), the lower the viscosity of the polyolefin. When the melt flow index (MFI) of the polypropylene is within the above range, the workability can be effectively improved and the physical properties of the final product can be effectively improved. Specifically, the polypropylene may have a melt flow index (MFI) of from about 0.5 g / 10 min to about 5 g / 10 min.

The polyethylene-polypropylene copolymer (PE-PP) may comprise about 1% to about 50% by weight of ethylene groups relative to the total content of the copolymer. When the content of the ethylene group in the polyethylene-polypropylene copolymer (PE-PP) is within the above range, the phase separation of the polypropylene and the polyethylene-polypropylene copolymer (PE-PP) can be effectively prevented or alleviated. In addition, it is possible to increase elongation at the time of stretching while having excellent light transmittance and orientation, and to realize improved polarization characteristics. Specifically, the polyethylene-polypropylene copolymer (PE-PP) may comprise about 1 wt% to about 25 wt% ethylene groups relative to the total amount of the copolymer.

The polyethylene-polypropylene copolymer (PE-PP) may have a melt flow index (MFI) of from about 5 g / 10 min to about 15 g / 10 min. When the melt flow index (MFI) of the polyethylene-polypropylene copolymer (PE-PP) is within the above range, the workability can be effectively improved and the physical properties of the final product can be effectively improved. Specifically, the polyethylene-polypropylene copolymer (PE-PP) may have a melt flow index (MFI) of about 10 g / 10 min to about 15 g / 10 min.

The polyolefin 71 may comprise, for example, polypropylene (PP) and a polyethylene-polypropylene copolymer (PE-PP) in a weight ratio of about 1: 9 to about 9: 1. When the polypropylene (PP) and the polyethylene-polypropylene copolymer (PE-PP) are contained within the above ranges, crystallization of the polypropylene can be prevented and the haze characteristics can be effectively improved while having excellent mechanical strength. Specifically, the polyolefin 71 can comprise polypropylene (PP) and a polyethylene-polypropylene copolymer (PE-PP) in a weight ratio of about 4: 6 to about 6: 4, more specifically about 5: have.

The polyolefin (71) may have a melt flow index (MFI) of about 1 g / 10 min to about 15 g / 10 min. When the melt flow index (MFI) of the polyolefin (71) is within the above range, no excessive crystals are formed in the resin, and excellent light transmittance can be ensured, and at the same time, have. Specifically, the polyolefin 71 may have a melt flow index (MFI) of about 5 g / 10 min to about 15 g / 10 min.

The polyolefin (71) may have a haze of about 5% or less. By having the polyolefin 71 have haze in the above range, the transmittance can be increased and excellent optical properties can be obtained. Specifically, the polyolefin (71) may have a haze of about 2% or less, more specifically about 0.5% to about 2%.

The polyolefin (71) may have a degree of crystallization of about 50% or less. By having the polyolefin 71 have the crystallinity in the above range, the haze can be lowered and excellent optical characteristics can be achieved. Specifically, the polyolefin (71) may have a crystallinity of about 30% to about 50%.

The polyolefin (71) may have a transmittance of about 85% or more in a wavelength range of about 400 to 780 nm. The polyolefin (71) is uniaxially stretched. The uniaxial direction may be the same as the length direction of the dichroic dye 72 described later.

The dichroic dye 72 is dispersed in the polyolefin 71 and arranged in one direction along the stretching direction of the polyolefin 71. The dichroic dye 72 can transmit only one polarizing quadrature component of two polarizing quadrature components with respect to a predetermined wavelength region.

The dichroic dye 72 may be included in an amount of about 0.01 to 5 parts by weight based on 100 parts by weight of the polyolefin (71). By including it in the above range, it is possible to exhibit sufficient polarization characteristics without lowering the transmittance when formed into a polarizing film. In the range of about 0.05 to 1 part by weight based on 100 parts by weight of the polyolefin (71).

The polarizing film 110 may have a dichroic ratio of about 2 to 14 at the maximum absorption wavelength? _Max of the visible light region. And may be about 3 to 10 within the above range. Here, the dichroic ratio is a value obtained by dividing the absorption of the plane polarized light in the direction perpendicular to the axis of the polymer by the polarization absorption in the horizontal direction thereof, and can be obtained by the following equation (1).

 [Equation 1]

_{DR = Log (1 / T ⊥} ) / Log (1 / T ∥)

In the above equation (1)

DR is the dichroic ratio of the polarizing film,

T _∥ is the light transmittance of the polarizing film to light incident parallel to the transmission axis of the polarizing film,

T _⊥ is the light transmittance of the polarizing film to the light incident perpendicular to the transmission axis of the polarizing film.

The dichroic ratio may indicate the degree to which the dichroic dyes 72 are aligned in one direction in the polarizing film 110, and may have a dichroic ratio in the range of visible light wavelengths, depending on the orientation of the polyolefin chain The orientation of the dichroic dye 72 can be induced and the polarization characteristics can be improved.

The polarizing film 110 may have a polarization efficiency of about 80% or more and a polarization efficiency of about 83 to 99.9% within the above range. Here, the polarization efficiency can be obtained by the following equation (2).

&Quot; (2) &quot;

PE (%) = [(T _∥ -T _⊥ ) / (T _∥ + T _⊥ )] ^1/2 ⅹ 100

In Equation (2)

PE is the polarization efficiency,

T _∥ is the transmittance of the polarizing film to light incident parallel to the transmission axis of the polarizing film,

T _⊥ is the transmittance of the polarizing film to light incident perpendicular to the transmission axis of the polarizing film.

The polarizing film 110 may have a relatively thin thickness of about 100 탆 or less, and may have a thickness of, for example, about 30 탆 to about 95 탆. By having a thickness in the above range, the thickness can be greatly reduced as compared with a polyvinyl alcohol polarizing plate requiring a protective layer such as triacetyl cellulose (TAC), and thus a thin display device can be realized.

The first and second phase delay layers 120a and 120b may be anisotropic liquid crystal layers including liquid crystal.

The liquid crystal may be in the form of a rigid-rod or a wide disk extending in one direction, and may be, for example, a monomer, an oligomer and / or a polymer.

The liquid crystal may be a reactive mesogenic liquid crystal, and may have, for example, one or more reactive crosslinking groups. The reactive mesogenic liquid crystal may be prepared by reacting, for example, a rod-shaped aromatic derivative having at least one reactive crosslinking group, a compound represented by propylene glycol 1-methyl, propylene glycol 2-acetate and P1-A1- (Z1-A2) n- And P2 each independently comprise acrylate, methacrylate, vinyl, vinyloxy, epoxy, or combinations thereof, wherein A1 and A2 are each independently 1 (1,4-phenylene), naphthalene-2,6-diyl group or a combination thereof, and Z1 represents a single bond, -COO-, -OCO-, or a combination thereof. And n is 0, 1 or 2), but the present invention is not limited thereto.

The liquid crystal of the first retardation layer 120a and the liquid crystal of the second retardation layer 120b may each independently have a positive or negative birefringence value [Delta] n. The birefringence value? N is a value obtained by subtracting the refractive index (n _o ) of the light propagating perpendicularly to the optical axis from the refractive index n _e of the light traveling horizontally with respect to the optical axis. The liquid crystal may be oriented in one direction along the optical axis.

For example, the liquid crystal of the first retardation layer 120a and the liquid crystal of the second retardation layer 120b may each independently have a refractive index satisfying the following relational expression 1A or 1B.

[Relation 1A]

n _x > n _y = n _z

[Relation 1B]

n _x & lt _; n _y = n _z

In the above-mentioned relational expression 1A or 1B,

n _x is the refractive index at a slow axis of the first phase delay layer and n _y is the refractive index at a fast axis of the first phase delay layer and the refractive index at the second axis of the second phase retardation layer, And n _z is the refractive index in the vertical direction to n _x and n _y .

For example, the liquid crystal of the first retardation layer 120a and the liquid crystal of the second retardation layer 120b may have a refractive index satisfying the relational expression 1A, respectively.

For example, the liquid crystal of the first retardation layer 120a and the liquid crystal of the second retardation layer 120b may have a refractive index satisfying the relational expression 1B, respectively.

For example, the liquid crystal of the first retardation layer 120a may have a refractive index satisfying the relational expression 1A, and the liquid crystal of the second retardation layer 120b may have a refractive index satisfying the relational expression 1B.

For example, the liquid crystal of the first retardation layer 120a may have a refractive index satisfying the relational expression 1B, and the liquid crystal of the second retardation layer 120b may have the refractive index satisfying the relational expression 1A.

The first phase delay layer 120a and the second phase delay layer 120b may each have a constant wavelength dispersion phase delay and the combination of the first phase delay layer 120a and the second phase delay layer 120b may be reversed And may have a wavelength dispersive phase delay. Here, the constant wavelength dispersion phase retardation means that the phase difference with respect to light in a short wavelength is larger than the phase difference with respect to light in a long wavelength, and the inverse wavelength dispersion phase retardation means that the phase difference with respect to light in a long wavelength is larger than the phase difference with respect to light in a short wavelength .

The phase delay may be represented by an in-plane retardation, and the in-plane retardation R _e1 of the first retardation layer 120a may be expressed as R _e1 = (n _x1 -n _y1 ) d ₁ , in-plane retardation of (120b) (R _e2) is _{R e2 = (n x2 -n y2} ) can be represented as d _2, a first total in-plane retardation of the phase retardation layer (120a) and the second phase delay layer (120b) (R _e0 ) can be expressed as R _e0 = (n _x0- n _y0 ) d ₀ . Where n _x1 is the refractive index of the first phase delay layer 120a in the slow axis, n _y1 is the refractive index in the fast axis of the first phase delay layer 120a, d ₁ is the refractive index of the first phase delay layer 120a, and a thickness, n _x2 is the second in which the refractive index in a slow axis of the phase retardation layer (120b), n _y2 is a refractive index in the fast axis of the second phase delay layer (120b), d ₂ is the second phase delay layer the thickness of the (120b), n _x0 is the first phase retardation layer (120a) and a refractive index in the slow axis of the combination of the second phase delay layer (120b), n _y0 is the first phase retardation layer (120a) and the 2, in which the refractive index in the fast axis of the combination of the phase retardation layer (120b) d ₀ is the sum thickness of the first phase retardation layer (120a) and the second phase delay layer (120b).

Therefore, the refractive index and / or the thickness of the first phase delay layer 120a and the second phase retardation layer 120b at the slow axis and / or the fast axis are changed to have the in-plane retardations R _e1 and R _e2 within a predetermined range .

For example, the in-plane retardation R _e1 of the first retardation layer 120a with respect to the reference wavelength may be about 230 nm to 300 nm, and the in-plane retardation R (n) of the second retardation layer 120b with respect to the incident light of the reference wavelength _e2) the plane of from about 110nm to may be 160nm, reference wavelength of the first phase retardation layer (120a) and the second phase delay layer (120b) overall in-plane retardation of the first phase retardation layer (120a) of the incident light of the phase difference Plane retardation (R _e2 ) of the second retardation layer (R _e1 ) and the second retardation layer (120b). For example, the total in-plane retardation R _e0 of the first and second retardation layers 120a and 120b with respect to incident light of a reference wavelength may be about 110 nm to 160 nm.

As described above, the retardation of the first retardation layer 120a and the retardation of the second retardation layer 120b may be greater than the retardation of the retardation layer 120a with respect to light of a shorter wavelength, in-plane retardation of the first phase retardation layer (120a) (R _e1) is _{R e1 (450nm)> R e1} (550nm)> R e1 can satisfy the (650nm), and the in-plane retardation (R _e2 of the second phase delay layer (120b) ) Can satisfy R _e2 (450 nm)> R _e2 (550 nm)> R _e2 (650 nm).

As described above, the combination of the first retardation layer 120a and the second retardation layer 120b may have a retardation with respect to light of a long wavelength greater than a retardation with respect to light with a short wavelength, a first phase retardation layer (120a) and a second total in-plane retardation (R _e0) of the phase retardation layer (120b) is _{R e0 (450nm) ≤R e0 (} 550nm) <R e0 (650nm) or R _e0 (450nm) for <R _e0 (550nm) may satisfy the ≤R _e0 (650nm).

The short wavelength dispersion of the first phase delay layer 120a can be represented by R _e1 (450 nm) / R _e1 (550 nm), and the second phase delay The short wavelength dispersion of the layer 120b can be expressed by R _e2 (450 nm) / R _e2 (550 nm). For example, the short-wavelength dispersion properties of the first and second retardation layers 120a and 120b may be about 1.1 to 1.2, respectively, and the short-wavelength dispersion properties of the first and second retardation layers 120a and 120b The overall short-wavelength dispersion may be from about 0.70 to about 0.99.

The long wavelength dispersion of the first phase delay layer 120a can be represented by R _e1 (650 nm) / R _e1 (550 nm), and the second phase delay The long wavelength dispersion of the layer 120b may be expressed as R _e2 (650 nm) / R _e2 (550 nm). For example, the long wavelength dispersion of the first phase delay layer 120a and the second phase delay layer 120b may be about 0.9 to 1.0, and the first phase delay layer 120a and the second phase delay layer 120b may have a The overall long wavelength dispersion may be about 1.01 to 1.20.

The thickness direction retardation R _th1 of the first phase delay layer 120a may be expressed by R _th1 = {[(n _{x1 +} n _y1 ) / 2] -n _z1 } d ₁ , retardation (R _th2) in the thickness direction of the layer (120b) is _{R th2 = {[(n x2} + n y2) / 2] -n z2} d and ₂ can be expressed by the first phase retardation layer (120a) and the second The thickness direction retardation R _th0 of the combination of the phase delay layer 120b may be expressed by R _th0 = {[(n _{x0 +} n _y0 ) / 2] -n _z0 } d ₀ . Where n _x1 is the refractive index in the slow axis of the first phase delay layer 120a, n _y1 is the refractive index in the fast axis of the first phase delay layer 120a, n _z1 is the refractive index in the fast axis of the first phase delay layer 120a perpendicular to n _x1 and n _y1 a refractive index in a direction, n _x2 is the second in which the refractive index in a slow axis of the phase retardation layer (120b), n _y2 is a refractive index in the fast axis of the second phase delay layer (120b), n _z2 is n _x2 and the refractive index of which in the direction perpendicular to the n _y2, n _x0 is a refractive index in a slow axis of the phase retardation layer (120), n _y0 is the refractive index in the fast axis of the phase retardation layer (120), n _z0 is n _x0 And the refractive index in a direction perpendicular to n _y0 .

The thickness direction retardation R _th0 of the first and second retardation layers 120a and 120b may be determined by the thickness direction retardation R _th1 of the first and second retardation layers 120a and 120b, ( _Rth2 ) of the thickness direction of the light- _shielding layer. For example, the thickness direction retardation R _th0 of the first and second retardation layers 120a and 120b with respect to the reference wavelength may be about -250 nm to 250 nm.

The first phase delay layer 120a and the second phase delay layer 120b may each have a thickness of 5 占 퐉 or less. For example, the first and second phase delay layers 120a and 120b may each have a thickness of about 0.5 μm to 5 μm. For example, the sum of the thicknesses of the first retardation layer 120a and the second retardation layer 120b may be about 1 탆 to 10 탆 and within the range of about 2 탆 to 8 탆.

As such, the first and second retardation layers 120a and 120b have greatly reduced thicknesses compared to the conventional polymer retardation layer, thereby greatly reducing the thickness of the optical film 300. [ Therefore, the thickness of the display device to which the optical film 300 is applied can also be reduced, thereby realizing a thin display device.

The first and second retardation layers 120a and 120b may be thinner than the first and second adhesive layers 115a and 115b, respectively, which will be described later.

The first phase delay layer 120a and the second phase delay layer 120b may be formed by applying a liquid crystal solution on a substrate. At this time, the first phase delay layer 120a and the second phase retardation layer 120b may be formed on the respective substrates or sequentially on one substrate. The substrate may be, for example, triacylcellulose (TAC), but is not limited thereto. The liquid crystal solution may include a liquid crystal and a solvent such as toluene, xylene, cyclohexanone, and the liquid crystal solution may be applied on the substrate by a solution process such as spin coating, bar coating, slit coating or ink jet coating. Drying the liquid crystal solution, and curing the liquid crystal using, for example, UV.

The first phase delay layer 120a and the second phase retardation layer 120b whose optical characteristics are controlled are respectively prepared and bonded to each other to realize an inverse wavelength dispersion delay and a? / 4 phase difference can be exhibited in the entire visible light region . Accordingly, the first phase delay layer 120a and the second phase delay layer 120b can effectively realize the circularly polarized light compensation function, and the optical film is formed together with the polarizing film 110 described above to improve the display characteristics of the display device can do.

The polarizing film 110 and the first retardation layer 120a and the first retardation layer 120a and the second retardation layer 120b are bonded to each other through the first and second adhesive layers 115a and 115b, . The first and second adhesive 115a and 115b may be, for example, pressure sensitive adhesive (PSA).

The first and second pressure-sensitive adhesives 115a and 115b may be a composition containing a viscous resin or a cured product thereof.

Examples of the adhesive resin include (meth) acrylic resin, urethane resin, polyisobutylene resin, styrene butadiene rubber, polyvinyl ether resin, epoxy resin, melamine resin, polyester resin, phenol resin, silicone resin, , Or combinations thereof, but are not limited thereto.

The adhesive resin may be synthesized from, for example, at least one monomer and / or oligomer, a reaction initiator and a crosslinking agent. The at least one monomer and / or oligomer may include, but is not limited to, alkyl (meth) acrylate. The reaction initiator may be, for example, benzoyl peroxide, acetyl peroxide, diaryl peroxide, hydrogen peroxide, potassium persulfate, 2,2'-azobisisobutyronitrile (AIBN) , But is not limited thereto. The crosslinking agent may be, for example, an isocyanate compound, an epoxy compound, an aziridine compound, a metal chelate compound, or a combination thereof, but is not limited thereto.

The tacky resin may have, for example, a hydroxyl group, a carboxyl group, a nitrogen-containing functional group, or a combination thereof.

The viscous resin may have a weight average molecular weight (Mw) of, for example, about 500,000 to about 1,800,000, and a weight average molecular weight (Mw) of about 600,000 to 1,500,000 within the above range.

The first and second adhesive 115a and 115b may each have a thickness of, for example, about 5 탆 to 25 탆. Within this range, the first and second adhesive 115a and 115b may each have a thickness of, for example, about 5 탆 to 12 탆.

The first and / or second adhesive 115a, 115b may have a storage modulus of at least about 0.2 MPa at a frequency of 10 Hz and room temperature (25 DEG C).

As described above, the first phase delay layer 120a and the second phase delay layer 120b may have a very thin thickness of about 0.5 占 퐉 to 5 占 퐉. The thicknesses of the first and second phase delay layers 120a and 120b may be less than the thickness of the first or second adhesive 115a or 115b and the thickness of the first phase delay layer 120a and the second phase The thickness of the retardation layer 120b may be about 0.05 to 0.8 times the thickness of the first or second adhesive 115a or 115b.

This embodiment may be achieved by adjusting the storage elastic modulus of the first and / or second adhesive 115a, 115b that are in contact with the first and / or second phase delay layer 120a and / or 120b, The durability of the first phase delay layer 120a and the second phase delay layer 120b can be secured. That is, when the storage elastic modulus of the first and / or second adhesive 115a and / or 115b is about 0.2 MPa or more, cracks are generated in the first phase retardation layer 120a and / or the second phase retardation layer 120b, And / or reduce the occurrence of wrinkles.

Furthermore, when the storage elastic modulus of the first and / or second adhesive 115a and 115b is about 0.2 MPa or more, when the optical film 300 is folded or bent, the first retardation layer 120a and / The generation of cracks and / or wrinkles can be remarkably reduced in the folded portion of the folded portion 120b. Accordingly, it is possible to reduce the external deformation of the optical film 300, and thus can be effectively applied to a flexible display device such as a foldable display device or a bendable display device, Can be improved.

The storage elastic modulus of the first and / or second adhesive 115a, 115b may be within the range of about 0.2 MPa to 8 GPa. The storage elastic modulus of the first and / or second adhesive 115a and 115b may be about 0.7 MPa or more within the above range, and may be about 0.7 MPa to 8 GPa within the above range.

The first and / or second adhesive 115a and 115b may have a 180 ° peeling force at room temperature of about 1500 gf / 25 mm or more for the first phase delay layer 120a or the second phase delay layer 120b. Here, the 180 占 peeling force is obtained by curing a sample to which the first or second retardation layer 120a or 120b, the first and / or second adhesive 115a or 115b and the polymer film are sequentially applied, Is an index for evaluating the adhesion between the first and second phase delay layers 120a and 120b and the first and / or second adhesive 115a and 115b. But it is not limited thereto within the range of about 1500 gf / 25 mm to 5000 gf / 25 mm.

The optical film 300 may further include a correction layer (not shown). The correction layer may be, for example, a color shift resistant layer, but is not limited thereto.

The optical film 300 may further include a light blocking layer (not shown) extending along the edge. The light shielding layer may be formed in the form of a band along the periphery of the optical film 300, for example, between the polarizing film 110 and the first retardation layer 120a. The light-shielding layer may comprise an opaque material, such as a black material. For example, the light-shielding layer can be made of black ink.

As described above, the optical film 300 according to the present embodiment realizes an inverse wavelength dispersion delay by joining the first phase delay layer 120a and the second phase retardation layer 120b whose optical characteristics are controlled, The? / 4 phase difference can be displayed in the entire region. Accordingly, the first and second retardation layers 120a and 120b may be combined to effectively implement the circularly polarized light compensating function, and the optical film may be formed together with the polarizing film 110 to improve display characteristics of the display device.

Also, the optical film 300 according to the present embodiment can greatly reduce the thickness of the optical film 300 by using the first phase delay layer 120a and the second phase retardation layer 120b having a very thin thickness. Therefore, the thickness of the display device to which the optical film 300 is applied can also be reduced, thereby realizing a thin display device.

Also, by adjusting the storage modulus of the first adhesive 115a and / or the second adhesive 115b which are in contact with the first phase delay layer 120a and / or the second phase delay layer 120b, It is possible to reduce the occurrence of cracks and wrinkles in the retardation layer 120a and the second phase retardation layer 120b and ensure durability. Therefore, the display characteristics of the display device to which the optical film 300 is applied can be improved.

When the optical film 300 is folded or bent by securing the durability of the first retardation layer 120a and the second retardation layer 120b as described above, the first retardation layer 120a and the second retardation layer 120b, Cracks and wrinkles can be remarkably reduced at the folded portion of the folded portion 120b and thus can be effectively applied to a flexible display device such as a foldable display device or a Ben-double display device.

The optical film 300 described above can be applied to various display devices.

A display device according to an embodiment includes a display panel and an optical film positioned on one side of the display panel. The display panel may be a liquid crystal display panel or an organic light emitting display panel, but is not limited thereto.

Hereinafter, an organic light emitting display will be described as an example of a display device.

4 is a cross-sectional view schematically showing an organic light emitting diode display according to one embodiment.

Referring to FIG. 4, the organic light emitting display according to one embodiment includes an organic light emitting display panel 400 and an optical film 300 located on one side of the organic light emitting display panel 400.

The OLED display panel 400 may include a base substrate 410, a lower electrode 420, an organic emission layer 430, an upper electrode 440, and an encapsulation substrate 450.

The base substrate 410 may be made of glass or plastic.

One of the lower electrode 420 and the upper electrode 440 may be an anode and the other may be a cathode. The anode is an electrode through which holes are injected. The anode may be made of a transparent conductive material having a high work function and emitting light to the outside, and may be, for example, ITO or IZO. The cathode is an electrode to which an electrode is injected. The cathode may be made of a conductive material having a low work function and not affecting an organic material, and may be selected from aluminum (Al), calcium (Ca), and barium (Ba) .

The organic light emitting layer 430 includes an organic material capable of emitting light when a voltage is applied to the lower electrode 420 and the upper electrode 440.

(Not shown) may be further provided between the lower electrode 420 and the organic light emitting layer 430 and between the upper electrode 440 and the organic light emitting layer 430. The sub-layer may include a hole transporting layer, a hole injecting layer, an electron injecting layer, and an electron transporting layer for balancing electrons and holes. have.

The encapsulation substrate 450 may be made of glass, metal, or polymer, and may seal the lower electrode 420, the organic emission layer 430, and the upper electrode 440 to prevent water and / .

The organic light emitting display panel 400 may be a flexible display panel.

The optical film 300 may be disposed on the side where light is emitted. For example, in the case of a bottom emission structure in which light is emitted toward the base substrate 410, it may be disposed outside the base substrate 410, and in the case of a top emission structure in which light is emitted toward the sealing substrate 450 And may be disposed outside the encapsulation substrate 450.

The optical film 300 comprises an integral polarizing film 110 made of a molten mixture of a polyolefin and a dichroic dye, first and second retardation layers 120a and 120b as liquid crystalline anisotropic layers, And second pressure-sensitive adhesive (115a, 115b). The polarizing film 110, the first and second retardation layers 120a and 120b and the first and second adhesive layers 115a and 115b are as described above. It is prevented from being reflected by a metal such as an electrode of the light emitting display panel 400 and coming out to the outside of the display device, thereby preventing deterioration of visibility due to light introduced from the outside. Therefore, the display characteristics of the organic light emitting display device can be improved.

Hereinafter, a liquid crystal display device will be described as an example of a display device.

5 is a cross-sectional view schematically showing a liquid crystal display device according to one embodiment.

Referring to FIG. 5, a liquid crystal display device according to one embodiment includes a liquid crystal display panel 500 and an optical film 300 positioned on one or both sides of the liquid crystal display panel 500.

The liquid crystal display panel 500 may be a twisted nematic (TN) mode, a patterned vertical alignment (PVA) mode, an in plane switching (IPS) mode, an optically compensated bend have.

The liquid crystal display panel 500 includes a first display panel 510, a second display panel 520 and a liquid crystal layer 530 interposed between the first display panel 510 and the second display panel 520.

The first display panel 510 may include a thin film transistor (not shown) formed on a substrate (not shown) and a first electric field generating electrode (not shown) connected thereto, 520 may include a color filter (not shown) and a second electric field generating electrode (not shown) formed on a substrate (not shown), for example. However, the present invention is not limited thereto. The color filter may be included in the first display panel 510, and the first electric field generating electrode and the second electric field generating electrode may be disposed together in the first display panel 510.

The liquid crystal layer 530 may include a plurality of liquid crystal molecules. The liquid crystal molecules may have a positive or negative dielectric constant anisotropy. When the liquid crystal molecules have a positive dielectric anisotropy, the long axis of the liquid crystal molecules is aligned so as to be substantially parallel to the surfaces of the first and second display plates 510 and 520 in the absence of an electric field, And may be oriented so as to be substantially perpendicular to the surfaces of the first display panel 510 and the second display panel 520. On the other hand, when the liquid crystal molecules have a negative dielectric anisotropy, the long axes of the liquid crystal molecules are oriented substantially perpendicular to the surfaces of the first and second display plates 510 and 520 in the absence of an electric field, The major axis can be oriented substantially parallel to the surfaces of the first display plate 510 and the second display plate 520.

The liquid crystal display panel 500 may be a flexible display panel.

The optical film 300 includes an integral polarizing film 110 made of a molten mixture of a polyolefin and a dichroic dye, first and second retardation layers 120a and 120b which are liquid crystalline anisotropic layers, and first and second pressure- (115a, 115b), as described above.

The optical film 300 is disposed on the outer side of the liquid crystal display panel 500 and is formed on the lower and upper portions of the liquid crystal display panel 500. However, It may be formed only on one of the upper portions.

Hereinafter, embodiments of the present invention will be described in detail with reference to examples. The following examples are for illustrative purposes only and are not intended to limit the scope of the invention.

Production of polarizing film

Production Example 1

100 parts by weight of a polyolefin containing polypropylene (PP) (HU300, manufactured by Samsung Total) and a polypropylene-polyethylene copolymer (PP-PE) (RJ581, Samsung Total) in a ratio of 5: 5 (w / , 0.5, 0.2 and 0.3 parts by weight of a dichroic dye represented by the following formulas (A), (B) and (C), respectively.

(A)

[Chemical Formula B]

&Lt; RTI ID = 0.0 &

The composition for polarizing film was melt-mixed at about 250 캜 using a DSM Micro-compounder. The molten mixture is put into a sheet-like mold and pressed with a high-temperature high-pressure press to produce a film. Subsequently, the film was uniaxially stretched (using an Instron tensile tester) at a magnification of 1000% at 115 캜 to prepare a polarizing film having a thickness of 20 탆.

Preparation of phase delay layer

Production Example 2

After photo-alignment in a single direction on a PET film having a thickness of 100 μm, a liquid crystal (MR2, manufactured by Dai Nippon Printing Co., Ltd.) is coated on the PET film and dried at 60 ° C. for 1 minute in a drying oven to remove the coating solvent. Next, the liquid crystal was photo-crosslinked by irradiating ultraviolet rays of 80 mW / cm 2 intensity in a container filled with nitrogen for 30 seconds to prepare a λ / 2 retardation layer having the optical characteristics shown in Table 1 below.

Production Example 3

After photo-alignment in a single direction on a 100 μm thick PET film, liquid crystal (MR4, Dai Nippon Printing Co., Ltd.) is coated and dried in a drying oven at 60 ° C. for 1 minute to remove the coating solvent. Then, the liquid crystal was photo-crosslinked by irradiating ultraviolet rays of 80 mW / cm 2 intensity in a container filled with nitrogen for 30 seconds to prepare a λ / 4 retardation layer having the optical characteristics shown in Table 1 below.

In-plane retardation (Re) Wavelength dispersibility Thickness direction retardation
(Rth) Thickness (㎛) Re (550 nm) R _e (450 nm) / R _e (550 nm) R _e (650 nm) / R _e (550 nm) λ / 2 240 1.16 0.97 110 2 λ / 4 120 1.12 0.99 57 One ? / 2 +? / 4 134 0.78 1.06 167 3

Preparation of Adhesive

Production Example 4

A three-necked flask equipped with a condenser, a stirrer and a thermometer was charged with 2-ethylhexyl acrylate

95 parts by weight of ethyl hexyl, 5 parts by weight of acrylic acid and 350 parts by weight of acetone, and sufficiently purged with nitrogen. While the solution was stirred in a nitrogen atmosphere, the polymerization vessel was heated to 80 占 폚, and 0.05 parts by weight of 2,2'-azobis isobutyronitrile was added thereto and reacted for 2 hours. Subsequently, 0.05 part by weight of 2,2'-azobisisobutyronitrile was further added, and the mixture was reacted for 5 hours. After completion of the reaction, the polymerization vessel was cooled and 100 parts by weight of ethyl acetate was added to obtain an acrylic polymer solution. The weight average molecular weight of the acrylic polymer solution is about 800,000.

10 parts by weight of modified polyisocyanate (Hardner, Toyoink) based on the solid content is added to 100 parts by weight of the solid content of the acrylic polymer solution to prepare a pressure-sensitive adhesive.

Production Example 5

A pressure-sensitive adhesive was prepared in the same manner as in Production Example 4, except that the modified polyisocyanate was added in an amount of 13 parts by weight based on the solids content.

Production Example 6

A pressure-sensitive adhesive was prepared in the same manner as in Production Example 4, except that 15 parts by weight of modified polyisocyanate was added based on the solid content.

Production Example 7

A pressure-sensitive adhesive was prepared in the same manner as in Production Example 4, except that 20 parts by weight of the modified polyisocyanate was added based on the solid content.

Production Example 8

A pressure-sensitive adhesive was prepared in the same manner as in Production Example 4 except that 0.2 part by weight of modified polyisocyanate was added in terms of solid content.

* Preparation Example 9

A pressure-sensitive adhesive was prepared in the same manner as in Production Example 4, except that 5 parts by weight of modified polyisocyanate was added based on the solid content.

Evaluation 1: Storage elastic modulus of pressure-sensitive adhesive

The storage elastic moduli of the pressure-sensitive adhesives according to Production Examples 4 to 9 were measured.

A polyester film having a thickness of 38 탆 was coated so that the thickness of the pressure-sensitive adhesive after drying was 10 탆 and heat-treated at 105 캜 for 5 minutes to prepare an adhesive film. Subsequently, a sample in which a plurality of adhesive films were laminated and a 500 탆 thick adhesive film laminated was cut into a circle having a diameter of 8 mm was prepared. Using a storage elasticity tester (Anton paar), a storage elastic modulus .

The results are shown in Table 2.

Storage modulus (MPa, 25 캜) Production Example 4 0.28 Production Example 5 0.72 Production Example 6 0.79 Production Example 7 1.60 Production Example 8 0.065 Production Example 9 0.12

Sample preparation for evaluation of peel strength of curable pressure-sensitive adhesive

Example 1

A pressure sensitive adhesive according to Production Example 4 was coated on the? / 2 phase retardation layer according to Production Example 2 to a thickness of 10 占 퐉 and heat-treated at 105 占 폚 for 5 minutes to prepare a pressure sensitive adhesive film having a thickness of 7 占 퐉. A polyethylene terephthalate (PET) film having a thickness of 100 mu m is attached to the adhesive film to prepare a sample.

Example 2

A sample is prepared in the same manner as in Example 1, except that the pressure-sensitive adhesive according to Production Example 5 is used instead of the pressure-sensitive adhesive according to Production Example 4. [

Example 3

A sample is prepared in the same manner as in Example 1, except that the pressure-sensitive adhesive according to Production Example 6 is used in place of the pressure-sensitive adhesive according to Production Example 4. [

Example 4

A sample is prepared in the same manner as in Example 1, except that the pressure-sensitive adhesive according to Production Example 7 is used instead of the pressure-sensitive adhesive according to Production Example 4. [

Evaluation 2: Evaluation of peel strength of adhesive

The samples according to Examples 1 to 4 were cut to a size of 25 mm x 200 mm and the polyethylene terephthalate (PET) film was peeled off at 180 degrees using a texture analyzer to evaluate the peeling force of the? / 2 retardation layer and the adhesive do.

The results are shown in Table 3.

Peel force (gf / 25 mm, 25 캜) Example 1 2650 Example 2 1530 Example 3 2550 Example 4 2520

Referring to Table 3, it can be seen that the samples according to Examples 1 to 4 exhibit a good peeling force and all have a room temperature peeling force of about 1500 gf / 25 mm or more.

Manufacture of optical film

Example 5

The pressure sensitive adhesive according to Production Example 8 was applied on one side of the polarizing film according to Production Example 1 to a thickness of 7 탆, and then the polarizing film and the? / 2 phase retarding layer according to Production Example 2 were arranged facing each other. Then, the? / 2 phase retardation layer is transferred onto the pressure sensitive adhesive while removing the PET film to produce an optical film. Next, a pressure sensitive adhesive according to Production Example 5 was applied to one surface of the? / 2 phase retardation layer to a thickness of 7 μm. The λ / 4 phase retardation layer according to Production Example 3 was disposed on the pressure-sensitive adhesive so as to face each other, and the λ / 4 phase retardation layer was transferred while the PET film was removed to produce an optical film. The optical axis of the polarizing film is 0 degrees, the slow axis of the? / 2 phase delay layer is 15 degrees, the slow axis of the? / 4 phase delay layer is 75 degrees, and the thickness of the optical film is about 40 占 퐉.

Example 6

An optical film was prepared in the same manner as in Example 5, except that the pressure-sensitive adhesive according to Production Example 6 was used in place of the pressure-sensitive adhesive according to Production Example 5. [

Example 7

An optical film was prepared in the same manner as in Example 5, except that the pressure-sensitive adhesive according to Production Example 5 was used in place of the pressure-sensitive adhesive according to Production Example 8.

Comparative Example 1

An optical film was prepared in the same manner as in Example 5, except that the pressure-sensitive adhesive according to Production Example 8 was used in place of the pressure-sensitive adhesive according to Production Example 5. [

Rating 3: High temperature durability 1

The high temperature durability of the optical films according to Examples 5 to 7 and Comparative Example 1 is evaluated.

The high-temperature durability was evaluated from the deformation and / or the damage of the folded portion by performing the static bending test, and the static bending test was conducted to measure the optical film according to Examples 5 to 7 and Comparative Example 1 between the two stainless steel plates, ) 3 mm, and then left to stand at 85 ° C for 240 hours, and then unfolded to evaluate the deformation of the folded portion.

The results are shown in FIGS.

6 is an external view of the optical film according to Example 5 attached to the reflector after the bending test, FIG. 7 is a photograph of the appearance of the optical film according to Example 6 having the reflector after the bending test, FIG. 8 is an external view of an optical film according to Example 7 having a reflection plate after performing a bending test, and FIG. 9 is an external view of an optical film according to Comparative Example 1 having a reflection plate after performing a bending test.

6 to 9, it can be confirmed that cracks and wrinkles are not generated in the folded portions of the optical films according to Examples 5 to 7, whereas the optical film according to Comparative Example 1 shows cracks and wrinkles along the diagonal lines at the folded portions, It can be confirmed that a large amount of wrinkles have occurred.

From these results, it can be confirmed that the optical films according to Examples 5 to 7 are excellent in high-temperature durability without external deformation.

Rating 4: High temperature durability 2

The retardation change after the optical film according to Example 5 and Comparative Example 1 was subjected to the static bending test described above was observed.

Before the static bending test, measure the initial phase difference using optical measuring equipment (KOBRA), and after the static bending test, measure the phase difference again using optical measuring equipment (KOBRA) to check the change value.

The results are shown in Table 4.

Phase difference change value Example 5 1.90 Comparative Example 1 2.60

Referring to Table 4, it can be seen that the optical film according to Example 5 has a retardation change of less than 2.0 in the folded portion, whereas the optical film according to Comparative Example 1 has a retardation change of 2.5 or more in the folded portion. Specifically, it can be seen that the optical film according to Example 5 has a retardation change value of about 30% or less as compared with the optical film according to Comparative Example 1. [

From this, it can be confirmed that the optical film according to Example 5 has a low durability at high temperature because the optical characteristics are small.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but, on the contrary, And it goes without saying that the invention belongs to the scope of the invention.

300: optical film 110: polarizing film
115a and 115b:
120a: first phase delay layer 120b: second phase delay layer
50: display panel 400: organic light emitting display panel
410: base substrate 420: lower electrode
430: organic light emitting layer 440: upper electrode
450: sealing substrate 500: liquid crystal display panel
510: first display panel 520: second display panel
530: liquid crystal layer

Claims (19)

A polarizing film comprising a polyolefin and a dichroic dye,
A first retardation layer disposed on one surface of the polarizing film and including a liquid crystal,
A second phase delay layer disposed on one surface of the first phase retardation layer and including a liquid crystal,
A first adhesive disposed between the polarizing film and the first retardation layer, and
And a second adhesive disposed between the first phase delay layer and the second phase delay layer,
Lt; / RTI &gt;
Wherein at least one of the first pressure-sensitive adhesive and the second pressure-sensitive adhesive has a room temperature storage elastic modulus of 0.2 MPa or more at a frequency of 10 Hz. The method of claim 1,
The pressure-sensitive adhesive may be at least one selected from the group consisting of (meth) acrylic compounds, urethane compounds, polyisobutylene compounds, styrene butadiene rubber, polyvinyl ether compounds, epoxy compounds, melamine compounds, polyester compounds, phenol compounds, silicone compounds, &Lt; / RTI &gt; or a combination thereof. The method of claim 1,
Wherein the pressure-sensitive adhesive comprises a resin having a hydroxyl group, a carboxyl group, a nitrogen-containing functional group, or a combination thereof. The method of claim 1,
Wherein the pressure-sensitive adhesive is a resin crosslinked using a crosslinking agent comprising an isocyanate compound, an epoxy compound, an aziridine compound, a metal chelate compound or a combination thereof. The method of claim 1,
Wherein the first retardation layer and the second retardation layer are thinner than the first adhesive or the second adhesive, respectively. The method of claim 5,
Wherein a thickness of the first retardation layer and a thickness of the second retardation layer are 0.05 to 0.8 times the thickness of the first adhesive or the second adhesive, respectively. The method of claim 5,
The thicknesses of the first pressure-sensitive adhesive and the second pressure-sensitive adhesive are 5 탆 to 25 탆, respectively,
The thicknesses of the first retardation layer and the second retardation layer are 0.5 to 5 mu m
Optical film. The method of claim 1,
Wherein the sum of the thicknesses of the first retardation layer and the second retardation layer is 1 占 퐉 to 10 占 퐉. The method of claim 1,
Wherein at least one of the first adhesive and the second adhesive has a room temperature storage elastic modulus of 0.2 to 8 GPa at a frequency of 10 Hz. The method of claim 1,
Wherein at least one of the first adhesive and the second adhesive has a 180 DEG peel force at room temperature of 1500 gf / 25 mm or more with respect to the first retardation layer or the second retardation layer. The method of claim 1,
Wherein either one of the first retardation layer and the second retardation layer has an in-plane retardation of from 230 nm to 300 nm with respect to a wavelength of 550 nm,
Wherein the other of the first phase delay layer and the second phase delay layer has an in-plane retardation of from 110 nm to 160 nm for a wavelength of 550 nm
Optical film. The method of claim 1,
Wherein the liquid crystal of the first retardation layer and the liquid crystal of the second retardation layer independently have an index of refraction satisfying the following relational expression 1A or 1B:
[Relation 1A]
n _x > n _y = n _z
[Relation 1B]
n _x & lt _; n _y = n _z
In the above relational expressions 1A and 1B,
n _x is a refractive index at a slow axis between the first and second phase delay layers and n _y is a fast axis of the first and second phase delay layers, And n _z is the refractive index in the vertical direction to n _x and n _y . The method of claim 1,
The in-plane retardation (R _e1 ) of the first phase retardation layer with respect to the wavelengths of 450 nm, 550 nm and 650 nm satisfies R _e1 (450 nm)> R _e1 (550 nm)> R _e1
The in-plane retardation (R _e2 ) of the second phase retardation layer with respect to the wavelengths of 450 nm, 550 nm and 650 nm satisfies R _e2 (450 nm)> R _e2 (550 nm)> R _e2
450nm, 550nm and overall in-plane retardation of said first phase retardation layer and the second phase delay layer for the wavelength of 650nm (R _e0) is _{R e0 (450nm) ≤R e0 (} 550nm) <R e0 (650nm) or R _{e0 (450nm) <R e0 (550nm} ) ≤R e0 optical film satisfying (650nm). The method of claim 13,
The short-wavelength dispersion properties of the first retardation layer and the second retardation layer are respectively 1.1 to 1.2,
Wherein the first retardation layer and the second retardation layer have an overall short wavelength dispersion of 0.70 to 0.99.
The method of claim 13,
The long wavelength dispersion of the first phase delay layer and the second phase delay layer is 0.9 to 1.0,
Wherein the first retardation layer and the second retardation layer have an overall long wavelength dispersion of from 1.01 to 1.20. The method of claim 1,
Wherein the polarizing film has a thickness of 100 mu m or less. Display panel, and
The optical film according to any one of claims 1 to 16, which is located on at least one surface of the display panel
. The method of claim 17,
Wherein the display panel includes a liquid crystal display panel or an organic light emitting display panel. The method of claim 17,
Wherein the display panel is a flexible display panel.

Images