KR102210260B1 - Retardation film, polarizing plate comprising the same and display apparatus comprising the same - Google Patents

Abstract

Inverse wavelength dispersion, in-plane retardation Re at a wavelength of 550 nm is 100 nm to 200 nm, a retardation film comprising a non-epoxy compound having a fluorene skeleton and an aromatic and aliphatic polycarbonate compound, a polarizing plate including the same, and comprising the same A display device is provided.

Description

A retardation film, a polarizing plate including the same, and a display device including the same {RETARDATION FILM, POLARIZING PLATE COMPRISING THE SAME AND DISPLAY APPARATUS COMPRISING THE SAME}

The present invention relates to a retardation film, a polarizing plate including the same, and a display device including the same.

In a display device such as a liquid crystal display (LCD) or an organic light emitting diode (OLED), a retardation film is used for the purpose of improving a viewing angle, improving display quality, or preventing reflection. The retardation film can be divided into one having a positive wavelength dispersion, a flat wavelength dispersion, and a reverse wavelength dispersion according to the wavelength dispersion characteristics. The retardation film having reverse wavelength dispersion refers to a retardation film having a property of increasing a retardation value generated as the wavelength of incident light increases.

In recent years, as a new display device, a self-luminous display device such as an organic electroluminescent display device has attracted attention. The self-luminous display device has a room for suppressing power consumption compared to a liquid crystal display device in which the backlight is always lit. In a self-luminous display device, such as an organic electroluminescent display device, in which a light source corresponding to each color is turned on, it is not necessary to provide a color filter that causes contrast reduction, and thus the contrast can be further increased. However, in an organic electroluminescent display device, in order to increase the light extraction efficiency, a reflector such as an aluminum plate is installed on the back side of the display, so that external light incident on the display is reflected by the reflector, thereby reducing the contrast of the image. There is. In order to solve this problem, for the purpose of preventing reflection of external light on the side, a method of using a circular polarizing plate with a λ/4 retardation film is known.

It is ideal that a λ/4 retardation film used in an organic electroluminescent display device substantially imparts a phase difference of λ/4 to a wide wavelength range of visible light. For this reason, it is required that the phase difference imparted to the light of a long wavelength is greater than the phase difference imparted to the light of a short wavelength to have reverse wavelength dispersion. However, in the current situation, it has been difficult to obtain a film capable of providing a phase difference of 1/4 wavelength, exhibiting sufficient reverse wavelength dispersion, and providing a phase difference of λ/4 to light in a wide wavelength range.

The background technology of the present invention is disclosed in Korean Patent Application Publication No. 10-2016-0006817.

An object of the present invention is to provide a retardation film capable of implementing reverse wavelength dispersion and in-plane retardation Re 100nm to 200nm at a wavelength of 550nm.

Another object of the present invention is to provide a retardation film capable of minimizing the deviation of the in-plane retardation in both MD (machine direction) and TD (transverse direction) directions.

Another object of the present invention is to provide a retardation film having low haze and excellent optical transparency.

Another object of the present invention is to provide a retardation film capable of implementing an in-plane retardation Re 100nm to 200nm in a wide wavelength range.

Another object of the present invention is to provide a polarizing plate and a display device including the retardation film of the present invention.

The retardation film of the present invention has a reverse wavelength dispersion and an in-plane retardation Re of 100 nm to 200 nm at a wavelength of 550 nm, and contains a non-epoxy compound having a fluorene skeleton and an aromatic and aliphatic polycarbonate compound as the base resin of the retardation film. I can.

The polarizing plate of the present invention may include a polarizing film and a retardation film of the present invention formed on one surface of the polarizing film.

An object of the present invention is to provide a retardation film having a light transmittance of 90% or more at a thickness of 30 μm to 80 μm.

The display device of the present invention may include the retardation film of the present invention or the polarizing plate of the present invention.

The present invention provides a retardation film capable of implementing reverse wavelength dispersion and in-plane retardation Re 100nm to 200nm at a wavelength of 550nm.

The present invention provides a retardation film capable of minimizing the deviation of the in-plane retardation in both MD and TD directions.

The present invention provides a retardation film having low haze and excellent optical transparency.

The present invention provides a retardation film capable of implementing an in-plane retardation Re 100nm to 200nm in a wide wavelength range.

The present invention provides a retardation film having a light transmittance of 90% or more at a thickness of 30 μm to 80 μm.

The present invention provides a polarizing plate and a display device including the retardation film of the present invention.

It will be described in detail so that those skilled in the art can easily implement the present invention by the accompanying embodiments. The present invention may be implemented in various different forms, and is not limited to the embodiments described herein. In order to clearly describe the present invention, parts not related to the description are omitted.

In the present specification, "in-plane retardation (Re)" is represented by the following equation A, "thickness direction phase difference (Rth)" is represented by the following Formula B, and "biaxiality degree (NZ)" may be represented by the following Formula C. have:

<Equation A>

Re = (nx-ny) x d

<Equation B>

Rth = ((nx + ny)/2-nz) x d

<Equation C>

NZ = (nx-nz)/(nx-ny)

(In Equations A to C, nx, ny, and nz are refractive indices in the slow axis direction, fast axis direction, and thickness direction of the retardation film at the measurement wavelength, respectively, and d is the thickness (unit: nm) of the retardation film). The "measurement wavelength" may be a wavelength of 450 nm, 550 nm or 650 nm.

In the present specification,'nx','ny', and'nz' mean refractive indices in the slow axis direction, fast axis direction, and thickness direction of a corresponding retardation film at a measurement wavelength.

The inventors of the present invention believe that the retardation film comprising a non-epoxy compound having a fluorene skeleton and an aromatic and aliphatic polycarbonate compound as the base resin of the retardation film, and the stretched retardation film has a reverse wavelength dispersion and an in-plane retardation Re of 100 nm at a wavelength of 550 nm. To 200 nm, the in-plane retardation deviation among the retardation films can be reduced, the haze of the retardation film can be significantly improved, and the in-plane retardation Re can be secured from 100 nm to 200 nm in a wide wavelength range. Was completed.

Hereinafter, a retardation film according to an embodiment of the present invention will be described.

The retardation film may include, as a base resin, a non-epoxy compound having a fluorene skeleton and an aromatic and aliphatic polycarbonate compound, and a stretched film. The aromatic and aliphatic polycarbonate compounds may enable the retardation film to implement an in-plane retardation of 100 nm to 200 nm at a wavelength of 550 nm. The non-epoxy clock compound having a fluorene skeleton may enable the retardation film to implement reverse wavelength dispersion. Through this, the retardation film can simultaneously implement reverse wavelength dispersion and in-plane retardation of 100 nm to 200 nm at a wavelength of 550 nm even with a single layer.

On the other hand, the polycarbonate compounds are aromatic and aliphatic, and at the same time, the difference in the glass transition temperature compared to the non-epoxy compound having a fluorene skeleton can be secured to 10°C or less, thereby stretching the unstretched film containing the base resin. When made, it is possible to reduce the deviation of the in-plane retardation in both MD and TD directions of the retardation film, implement an in-plane retardation of 100 nm to 200 nm in a wide wavelength range, and reduce the haze of the retardation film.

In one embodiment, the retardation film may have an in-plane retardation Re of 100 nm to 200 nm, for example, 100 nm to 150 nm, for example, a quarter retardation at a wavelength of 550 nm. In the above range, when used for a polarizing plate for a light emitting display device, a side reflectance of external light may be lowered to improve screen quality.

In one embodiment, the retardation film satisfies the following Equation 1 and Equation 2 to achieve reverse wavelength dispersion: The retardation film exhibits reverse wavelength dispersion, thereby lowering the side reflectance of external light when used in a polarizing plate for a light emitting display device. Screen quality can be improved:

[Equation 1]

0.7 ≤ Re(450)/Re(550) ≤ 0.9

[Equation 2]

1.0 <Re(650)/Re(550) ≤ 1.3

(In Equations 1 and 2, Re (450) is the in-plane retardation (unit: nm) at the wavelength of the retardation film at 450 nm, Re (550) is the in-plane retardation (unit: nm) at the wavelength of the retardation film at 550 nm, Re (650 ) Is the in-plane retardation at a wavelength of 650 nm of the retardation film (unit: nm)).

For example, in the retardation film, Re(450)/Re(550) of Formula 1 may be 0.75 to 0.86, preferably 0.8 to 0.85. For example, in the retardation film, Re(650)/Re(550) of Equation 2 may be 1.02 to 1.2, preferably 1.05 to 1.19.

For example, the retardation film may have a Re (450) of 105nm to 130nm, preferably 110nm to 128nm, 110nm to 125nm. In the above range, there may be an anti-reflection effect. For example, the retardation film Re (650) may be 143nm to 170nm, preferably 143nm to 166nm. In the above range, there may be an anti-reflection effect.

In one embodiment, the retardation film may have a deviation of the in-plane retardation of Equations 3 and 4 of 0nm to 5nm. In the above range, since the in-plane retardation of the retardation film is uniform, the availability of the retardation film can be increased, and when used for a polarizing plate, the screen quality can be improved:

[Equation 3]

Deviation of the in-plane phase difference on the MD side = Re(max)-Re(min)

(In Equation 3, for a rectangular specimen of 3 cm in the MD direction and 2 cm in the TD direction of the retardation film, five points are displayed at 0.3 cm intervals in the MD direction, and the in-plane retardation at a wavelength of 550 nm is measured at that point, and measured. Among the phase difference in one plane, the maximum value is called Re(max) (unit: nm), and the minimum value is called Re(min) (unit: nm)).

[Equation 4]

Deviation of in-plane phase difference on the TD side = Re(max)-Re(min)

(In Equation 4, for a rectangular specimen of 3 cm in the MD direction and 2 cm in the TD direction of the retardation film, five points are displayed at 0.3 cm intervals in the TD direction, and the in-plane retardation at a wavelength of 550 nm is measured at that point, and measured. Among the phase difference in one plane, the maximum value is called Re(max) (unit: nm), and the minimum value is called Re(min) (unit: nm)).

Preferably, the deviation of Equations 3 and 4 can be measured multiple times and calculated as an average value. The deviation of the in-plane phase difference of Equations 3 and 4 may be measured with reference to the experimental examples described below.

In one embodiment, the retardation film may have a haze of 0% to 3%, preferably 0% to 1%. In the above range, when used in a polarizing plate for a light emitting display device, optical transparency can be improved, and even when stacked with a positive C layer, it can be used in a polarizing plate.

In one embodiment, the retardation film may be a two-component retardation film made of only a non-epoxy compound having a fluorene skeleton and an aromatic and aliphatic polycarbonate compound as a base resin. Aromatic and aliphatic polycarbonate compounds have high compatibility with non-epoxy compounds having a fluorene skeleton, so even if they do not contain a compatibilizing agent such as an epoxy compound having a fluorene skeleton, the haze of the retardation film can be reduced. In-plane phase difference deviation of Equations 3 and 4 can be reduced.

In one embodiment, the retardation film may have a glass transition temperature of 115°C to 150°C, preferably 125°C to 145°C. In the above range, a change in phase difference due to shrinkage at 80°C or higher is minimized, and there may be an effect of having durability reliability.

In one embodiment, the retardation film may have a first glass transition temperature implemented by a non-epoxy compound having a fluorene skeleton, and a second glass transition temperature implemented by an aromatic and aliphatic polycarbonate compound. The first glass transition temperature and the second glass transition temperature may be 115°C to 150°C, and preferably 125°C to 145°C, respectively. The first glass transition temperature and the second glass transition temperature may be the same or different from each other.

In one embodiment, the retardation film may have a thickness of more than 0 μm and 100 μm or less, for example, 30 μm to 80 μm, 40 μm to 60 μm. In the above range, it can be used for a polarizing plate for a light emitting display device.

In one embodiment, the retardation film may have a retardation Rth in the thickness direction at a wavelength of 550 nm of 30 nm to 100 nm, for example, 40 nm to 80 nm. In the above range, there may be an effect of minimizing side reflection by being laminated with the positive C film.

In one embodiment, the retardation film may have a biaxial degree NZ of 0.95 to 1.05, for example, 0.96 to 1.03 at a wavelength of 550 nm. In the above range, there is an effect of having a reverse wavelength characteristic in the entire area of visible light, and in particular, a difference in compensation characteristics for each wavelength can be eliminated, thereby maximizing the effect.

In one embodiment, the retardation film may be a non-epoxy clock retardation film having no epoxy group. As described in the present specification, even if the retardation film of the present invention is formed of only a non-epoxy compound having a fluorene skeleton and an aromatic and aliphatic polycarbonate compound without an epoxy compound as a base resin, all the effects of the present invention can be realized. .

In one embodiment, the non-epoxy compound having a fluorene skeleton and the aromatic and aliphatic polycarbonate compounds in the retardation film do not react with each other. Therefore, it may be a non-urethane-based retardation film that does not contain a urethane bond derived from a compound having a conventional fluorene skeleton.

In one embodiment, the retardation film may have a refractive index of 1.45 to 1.55, preferably 1.49 to 1.52. In the above range, there may be an effect of phase difference expression.

Hereinafter, the base resin constituting the retardation film of the present invention will be described.

The base resin may form a matrix of a retardation film and implement a retardation of the retardation film by stretching.

The non-epoxy compound having a fluorene skeleton may include a compound having a fluorene skeleton but not an epoxy functional group. The non-epoxy clock compound having a fluorene skeleton can allow the retardation film to exhibit reverse wavelength dispersion.

The non-epoxy compound having a fluorene skeleton may include a monomer, oligomer, or resin. When the non-epoxy compound having a fluorene skeleton is a monomer, the glass transition temperature in the homopolymer state may be 200°C to 350°C, preferably 220°C to 300°C. When the non-epoxy compound having a fluorene skeleton is an oligomer or resin, the glass transition temperature may be 115°C to 150°C, preferably 125°C to 145°C. Within the above range, shrinkage is minimized at high temperature and high humidity, thereby minimizing phase difference change and increasing durability reliability.

In one embodiment, the non-epoxy compound having a fluorene skeleton may include a cardo type polyester compound having a bisarylfluorene skeleton, for example, a 9,9-bisarylfluorene skeleton. .

In one embodiment, the non-epoxy compound having a fluorene skeleton may contain a bisarylfluorene skeleton and an alicyclic hydrocarbon group (eg, cyclohexane group) skeleton.

For example, the non-epoxy compound having a fluorene skeleton may include units represented by the following Chemical Formulas 1 and 2, and the order of their arrangement is not particularly limited. In one embodiment, the unit of Formula 1 may be contained in an amount of 50 mol% to 80 mol% of the compound, and the unit of Formula 2 may be included in an amount of 20 mol% to 50 mol% of the compound;

<Formula 1>

(In Formula 1, * is a connection site,

R1 and R2 are each independently an alkylene group having 1 to 10 carbon atoms,

R3 is a cycloalkylene group having 3 to 10 carbon atoms)

<Formula 2>

(In Formula 2, * is a connection site,

Each R4 is independently an alkylene group having 1 to 10 carbon atoms,

R5 is a C3-C10 cycloalkylene group)

In one embodiment, the non-epoxy compound having a fluorene skeleton may be represented by Formula 3:

<Formula 3>

(In Chemical Formula 3,

0<m<1, 0<n<1, m+n=1

n is m+0.2 to m+0.4)

The aromatic-based and aliphatic polycarbonate compounds can achieve an in-plane retardation at a wavelength of 550 nm of the present invention. In addition, aromatic and aliphatic polycarbonate compounds can increase compatibility with non-epoxy compounds having a fluorene skeleton, thereby lowering the deviation of the phase difference in the plane and lowering the haze. Through this, even if the base resin does not contain an epoxy-based compound having a fluorene skeleton, it is possible to reduce the deviation of the phase difference in the plane and reduce the haze.

The aromatic and aliphatic polycarbonate compounds may have positive wavelength dispersion. Through this, the retardation in the Re direction can be expressed, and an effect of obtaining a wavelength of λ/4 can be achieved.

Aromatic and aliphatic polycarbonate compounds may have a glass transition temperature difference of 0°C to 10°C, preferably 0°C to 5°C, compared to a non-epoxy compound having a fluorene skeleton. In the above range, even if the unstretched film is stretched, the deviation of the in-plane retardation can be reduced and the haze can be reduced.

The aromatic and aliphatic polycarbonate compounds are aromatic and aliphatic polycarbonate resins and may have a glass transition temperature of 115°C to 150°C, preferably 125°C to 145°C. In the above range, there may be an effect of obtaining excellent durability and reliability.

The aromatic and aliphatic polycarbonate compounds may include a polycarbonate resin having both an aromatic unit and an aliphatic unit. The polycarbonate resin may include a block copolymer in which aromatic units and aliphatic units are alternately arranged. The aromatic unit may mean a substituted or unsubstituted arylene group having 6 to 20 carbon atoms or an arylalkylene group. The aliphatic unit may mean a linear or branched substituted or unsubstituted alkylene group having 1 to 10 carbon atoms. In one embodiment, the aromatic unit may be a bisphenol type (eg, bisphenol A type). In one embodiment, the aliphatic unit may mean a linear alkylene group.

The base resin may be composed of only non-epoxy compounds having a fluorene skeleton and aromatic and aliphatic polycarbonate compounds. At this time, the non-epoxy compounds having a fluorene skeleton and the aromatic and aliphatic polycarbonate compounds are 50 parts by weight to 99.9 parts by weight of the non-epoxy compounds having a fluorene skeleton out of a total of 100 parts by weight, and aromatic and aliphatic polycarbonate compounds. The carbonate compound may be included in an amount of 0.1 to 50 parts by weight. In the above range, the in-plane phase difference can be well implemented, and there may be an effect that the elongation ratio can be easily adjusted. Preferably, the non-epoxy compound having a fluorene skeleton is 80 to 99 parts by weight, more preferably 90 to 99 parts by weight, and the aromatic and aliphatic polycarbonate compounds are 1 to 20 parts by weight. , More preferably, it may be included in 1 to 10 parts by weight. Non-epoxy compounds having a fluorene skeleton and non-epoxy compounds having a fluorene skeleton out of the total 100 parts by weight of a total of 100 parts by weight of a non-epoxy compound having a fluorene skeleton and an aromatic and aliphatic polycarbonate compound: 50:50 to 99.9:0.1 , Preferably it may be included in a weight ratio of 80:20 to 99:1, 90:10 to 99:1.

The retardation film may be prepared from a composition for a retardation film including the base resin. In the composition for the retardation film, the base resin may be included in an amount of 90 to 100 parts by weight, preferably 95 to 100 parts by weight based on solid content. In the above range, even if the unstretched film is stretched, there is no film breakage, and reverse wavelength dispersion and in-plane retardation can be realized.

The composition for a retardation film may further include an additive (a compound other than a fluorene compound, an epoxy compound, or a polycarbonate compound) as needed in addition to the base resin. The additives include fillers, reinforcing agents, coloring agents (dyes or pigments), conductive agents, flame retardants, plasticizers, lubricants, stabilizers (heat stabilizers or antioxidants), curing agents, curing accelerators, release agents, antistatic agents, flow modifiers, leveling agents, dispersants, It may include one or more of a defoaming agent and a surface modifier, but is not limited thereto. Additives may be included alone or in combination of two or more.

In one embodiment, the retardation film may further include rod-shaped nanoparticles. Rod-shaped nanoparticles are long and thin rod-shaped nanoparticles, meaning nanoparticles having a major axis and a minor axis. Rod-shaped nanoparticles have a higher refractive index in the thickness direction compared to the surface direction, so when the rod-shaped nanoparticles are included in the film and then stretched, the rod-shaped nanoparticles are arranged in the stretching direction, thereby increasing the refractive index in the thickness direction, thereby stably implementing the phase difference of the present invention. And increase the strength of the film. The rod-shaped nanoparticles may have a refractive index ratio of a refractive index in a major axis direction: a refractive index in a minor axis direction of 1:1.2 to 1:1.7. In the above range, the retardation of the present invention can be better expressed when the film is stretched. The rod-shaped nanoparticles may have a length aspect ratio of 1.5:1 to 3:1, preferably 2:1 to 3:1. In the above range, the retardation of the present invention may be exhibited when the film is stretched, the total light transmittance of the film may be increased, and the film may not be crushed when mixed with a resin. The aspect ratio refers to the ratio of the long axis, that is, the length, of the rod-shaped nanoparticles to the diameter of the cross-section, that is, the short axis of the rod-shaped nanoparticles. The rod-shaped nanoparticles may have a short axis of 5 nm to 50 nm, preferably 10 nm to 30 nm, and a long axis of 30 nm to 150 μm. In the above range, the strength of the film can be increased, and desired birefringence can be achieved.

The rod-shaped nanoparticles exhibit negative optical anisotropy and may include, for example, one or more of strontium carbonate (SrCO ₃ ), calcium carbonate, magnesium carbonate, zirconium carbonate, cobalt carbonate, and manganese carbonate, and preferably the present invention Strontium carbonate can be used for the aromatic vinyl-based monomer, acid anhydride-based monomer, and comonomer. The rod-shaped nanoparticles may be those that are not surface-treated, but those that have been surface-treated with a titanate compound such as titanium-based may be used.

The rod-shaped nanoparticles may be included in an amount of 1% to 15% by weight, preferably 2% to 10% by weight of the retardation film. In the above range, the effect of the film of the present invention may be achieved by increasing the refractive index in the thickness direction of the retardation film.

The retardation film can be produced by forming or molding the composition for a retardation film using a conventional film forming method, casting method, melt extrusion method, calendering method, etc. to prepare an unstretched film, and then stretching the prepared unstretched film. . The stretching may be uniaxial stretching or biaxial stretching, preferably biaxial stretching. Further, stretching may be performed by oblique stretching. Uniaxial stretching includes fixed width uniaxial stretching. The draw ratio may be 1.5 to 4.5 times the MD draw ratio and/or 1.5 to 4.5 times the TD draw ratio based on the uniaxial draw. Biaxial stretching may be increased to 1.1 times to 1.5 times in TD after stretching 1.5 to 4.5 times in the MD direction. The stretching temperature may be 125°C to 160°C, preferably 135°C to 155°C. In the above range, there may be an effect of minimizing phase difference and in-plane deviation due to stretching. Stretching is a stretching treatment performed on an unstretched film after film formation or molding, and the stretching method is not particularly limited, and a wet stretching or dry stretching, a tenter method, a tube method, or the like can be employed.

Hereinafter, the polarizing plate of the present invention will be described.

The polarizing plate may include a polarizing film and a retardation film of the present invention formed on one surface of the polarizing film. Since the polarizing plate is used in a light-emitting display device, it is possible to improve screen quality by lowering the side reflectance of external light.

In one embodiment, the polarizing plate may include a polarizing film and a retardation film of the present invention formed on a lower surface of the polarizing film. An adhesive film is further formed on the lower surface of the retardation film, so that the polarizing plate may be laminated on the panel for a light emitting display device.

In one embodiment, the polarizing film may be a polarizer. Specifically, the polarizer may include a polyvinyl alcohol-based polarizer manufactured by uniaxially stretching a polyvinyl alcohol-based film, or a polyene-based polarizer manufactured by dehydrating a polyvinyl alcohol-based film. The polarizer may have a thickness of 5 μm to 40 μm. In the above range, it can be used in a display device.

In another embodiment, the polarizing film may include a polarizer and a protective layer formed on at least one surface of the polarizer. The protective layer protects the polarizer, thereby increasing the reliability of the polarizing plate and increasing the mechanical strength of the polarizing plate.

The protective layer may include one or more of optically transparent, protective film or protective coating layer. The protective film includes a cellulose ester resin including triacetylcellulose (TAC), a cyclic polyolefin resin including amorphous cyclic polyolefin (COP), a polycarbonate resin, polyethylene terephthalate (PET), etc. Poly(meth)acrylates including polyester resins, polyethersulfone resins, polysulfone resins, polyamide resins, polyimide resins, non-cyclic-polyolefin resins, polymethylmethacrylate resins, etc. A film formed of at least one of resin, polyvinyl alcohol-based resin, polyvinyl chloride-based resin, and polyvinylidene chloride-based resin may be included, but is not limited thereto. The protective coating layer may be formed of an active energy ray-curable resin composition containing an active energy ray-curable compound and a polymerization initiator. The active energy ray-curable compound may include at least one of a cationic polymerizable curable compound, a radical polymerizable curable compound, a urethane resin, and a silicone resin.

A functional coating layer may be additionally formed on the other side of the polarizing film. The functional coating layer may include, but is not limited to, one or more of a primer layer, a hard coating layer, an anti-fingerprint layer, an antireflection layer, an anti-glare layer, a low reflection layer, and an ultra low reflection layer.

The angle formed by the absorption axis (MD of the polarizer) of the polarizing film and the optical axis of the retardation film may be 43° to 47°. In the above range, there may be an effect of reducing reflectance.

The retardation film may be directly laminated on the polarizing film. That is, the optical film may be laminated by contacting the polarizing film without an adhesive layer, an adhesive layer, or an adhesive layer.

The retardation film may be laminated on the polarizing film by an adhesive layer, an adhesive layer, or an adhesive layer. The adhesive layer, the adhesive layer, or the pressure-sensitive adhesive layer may be formed of a conventional pressure-sensitive adhesive known to those skilled in the art, but is not limited thereto.

In another embodiment, the polarizing plate may include a polarizing film, and a laminate of a retardation film of the present invention and a positive C plate formed on a lower surface of the polarizing film. A retardation film and a positive C plate may be sequentially formed from a polarizing film, or a positive C plate and a retardation film may be sequentially formed from a polarizing film. This can increase the anti-reflection effect of external light. An adhesive film is further formed on the lower surface of the laminate, so that the polarizing plate may be laminated on the panel for a light emitting display device.

The positive C plate may have a retardation Rth in the thickness direction of -40 nm to -80 nm at a wavelength of 550 nm. In the above range, it is possible to obtain an effect of preventing reflection of external light together with the retardation film.

Hereinafter, a display device of the present invention will be described.

The display device of the present invention may include at least one of the retardation film of the present invention and the polarizing plate of the present invention. In an embodiment, the display device may include a liquid crystal display device, a light emitting device display device, preferably a light emitting device display device, and the like. The light emitting device display device includes an organic or organic light emitting device, and includes a light emitting material such as a light emitting diode (LED), an organic light emitting diode (OLED), a quantum dot light emitting diode (QLED), and a phosphor. It may mean a light emitting device.

Hereinafter, the configuration and operation of the present invention will be described in more detail through preferred embodiments of the present invention. However, the following examples are for aiding understanding of the present invention, and the scope of the present invention is not limited to the following examples.

Example One

As a non-epoxy compound having a fluorene skeleton, a fluorene-based polyester resin (TS9HT4, OSAKA CHEMICAL, glass transition temperature: 129°C) was used. As aromatic and aliphatic polycarbonate compounds, a block copolymer polycarbonate resin (HFD1910, SABIC, glass transition temperature: 130°C) in which aromatic units and aliphatic units are alternately copolymerized was used.

A mixture obtained by mixing the fluorene-based polyester resin and the polycarbonate resin in a weight ratio of 99:1 was supplied to a 30φ extruder. Nitrogen was substituted from the hopper to the extruder. The mixture was melted at 250° C. to prepare a raw material pellet.

The prepared raw material pellets were passed through a coat hanger type T-die, and a non-stretched film having a thickness of 100 μm was prepared through a chrome plating casting roll and a drying roll. The prepared unstretched film was uniaxially stretched twice in MD at a stretching temperature of 140° C. to prepare a phase difference film having a thickness of 50 μm uniaxially stretched.

Example 2

In Example 1, a retardation film was prepared in the same manner as in Example 1, except that stretching was performed at 2.4 times by MD and 1.1 times by TD.

Example 3

In Example 1, a retardation film was prepared in the same manner as in Example 1, except that a mixture of the fluorene-based polyester resin and the polycarbonate resin in a weight ratio of 98:2 was used.

Example 4

In Example 1, the same method as in Example 1 was used, except that a mixture of the fluorene-based polyester resin and the polycarbonate resin in a weight ratio of 95:5 was used, and the stretching temperature was 155°C. The film was prepared.

Comparative example One

A polycarbonate resin (T7430, Mitsubishi) was used at 240° C. using a T-die film forming machine to prepare an unstretched film having a thickness of 100 μm. The prepared unstretched film was stretched 1.5 times in MD at 140°C to prepare a retardation film having a thickness of 50 μm.

Comparative example 2

Styrene-methacrylic-maleic anhydride resin (R310, DENKA) was used at 260° C. using a T-die film forming machine to prepare an unstretched film having a thickness of 100 μm. The prepared unstretched film was stretched 1.5 times in MD at 155°C to prepare a retardation film having a thickness of 50 μm.

Comparative example 3

As a non-epoxy compound having a fluorene skeleton, a fluorene-based polyester resin (TS9HT4, OSAKA CHEMICAL, glass transition temperature: 129°C) was used. As an aromatic polycarbonate compound, a polycarbonate resin having an aromatic unit (OQ-1028, manufactured by Sabic, glass transition temperature: 145°C, no aliphatic unit) was used.

A mixture obtained by mixing the fluorene-based polyester resin and the polycarbonate resin in a weight ratio of 99:1 was supplied to a 30φ extruder. Nitrogen was substituted from the hopper to the extruder. The mixture was melted at 250° C. to prepare a raw material pellet. The prepared raw material pellets were passed through a coat hanger-type tee die, and a non-stretched film having a thickness of 100 μm was prepared through a chrome plating casting roll and a drying roll. The prepared unstretched film was uniaxially stretched twice in MD at a stretching temperature of 140° C. to prepare a retardation film having a thickness of 50 μm uniaxially stretched.

The following physical properties were evaluated for the retardation films prepared in Examples and Comparative Examples, and the results are shown in Tables 1 and 2 below.

(1) In-plane retardation (unit: nm), thickness direction retardation (unit: nm) and degree of biaxiality: In-plane retardation (@ wavelengths 550 nm, 450 nm, 650 nm) was determined by using Axoscan for the retardation films prepared in Examples and Comparative Examples. It was measured using. In the same way, the retardation in the thickness direction (@ wavelength of 550 nm) was measured using Axoscan.

(2) Haze (unit: %): For the retardation films prepared in Examples and Comparative Examples, haze was measured using a haze measuring device.

(3) Deviation of in-plane retardation (unit: nm): For the retardation films prepared in Examples and Comparative Examples, a rectangular specimen of 3 cm in the MD direction and 2 cm in the TD direction was cut off. For the obtained rectangular specimen, five points were marked at intervals of 0.3 cm in the MD direction, and the in-plane retardation at a wavelength of 550 nm was measured at that point. The difference between the maximum and minimum values among the measured in-plane retardation was calculated, and the deviation of the in-plane retardation was calculated according to Equation 3.

Regarding the retardation films prepared in Examples and Comparative Examples, rectangular specimens of 3 cm in the MD direction and 2 cm in the TD direction were knitted. For the obtained rectangular specimen, five points were marked at 0.3 cm intervals in the TD direction, and the in-plane retardation at a wavelength of 550 nm was measured at that point. The difference between the maximum value and the minimum value among the measured in-plane phase difference was calculated, and the deviation of the in-plane phase difference was calculated according to Equation 4.

Example 1 Example 2 Example 3 Example 4 Weight ratio of base resin 99:1 99:1 98:2 95:5 Re(550) 139 135 145 142.1 Re(450) 116.76 113.4 126.15 117.8 Re(650) 147.34 143.55 152.25 151 Rth(550) 63 67 68 66 NZ 0.9683 0.9645 0.9714 0.966 Re(450)/Re(550) 0.84 0.84 0.87 0.83 Re(650)/Re(550) 1.06 1.06 1.05 1.06 Haze 0.93 0.93 0.94 0.97 Deviation from Equation 3 2 2 3 4 Deviation from Equation 4 2 2 3 4

* Weight ratio of base resin = Non-epoxy compound with fluorene skeleton: Weight ratio of aromatic and aliphatic polycarbonate compounds

Comparative Example 1 Comparative Example 2 Comparative Example 3 Base resin Polycarbonate Styrene-methacrylic-maleic anhydride resin 99:1 Re(550) 350 316 166 Re(450) 357 338.12 155 Re(650) 343 303.36 169 Rth(550) 190 -162 79 Re(450)/Re(550) 1.02 1.07 0.93 Re(650)/Re(550) 0.98 0.96 1.02 Haze 0.95 0.98 0.98 Deviation from Equation 3 3 6 9 Deviation from Equation 4 3 6 9

*99:1 = non-epoxy compound having a fluorene skeleton: weight ratio of aromatic polycarbonate compound

As shown in Table 1, the retardation film of the present invention has an in-plane retardation Re 100nm to 200nm due to reverse wavelength dispersion, it is possible to minimize the deviation of the in-plane retardation in both MD and TD directions, and has excellent optical transparency due to low haze.

On the other hand, Comparative Examples 1 and 2, which did not contain the base resin of the present invention at all, could not obtain all the effects of the present invention. In addition, Comparative Example 3 containing a non-epoxy compound having a fluorene skeleton but containing an aromatic polycarbonate compound without an aliphatic unit had a remarkably large deviation in the in-plane phase difference in both MD and TD directions.

Simple modifications or changes of the present invention can be easily implemented by those of ordinary skill in the art, and all such modifications or changes can be considered to be included in the scope of the present invention.

Claims (19)

As a retardation film having reverse wavelength dispersion and an in-plane retardation Re of 100 nm to 200 nm at a wavelength of 550 nm,
As a base resin of the retardation film, it includes a mixture of a non-epoxy compound having a fluorene skeleton and an aromatic and aliphatic polycarbonate compound,
The retardation film is that the deviation of the in-plane retardation of Equation 3 and Equation 4 is 0 nm to 5 nm, respectively:
[Equation 3]
Deviation of the in-plane phase difference on the MD side = Re(max)-Re(min)
(In Equation 3, for a rectangular specimen of 3 cm in the MD direction and 2 cm in the TD direction of the retardation film, five points are displayed at 0.3 cm intervals in the MD direction, and the in-plane retardation at a wavelength of 550 nm is measured at that point, and measured. The maximum value of the phase difference in one plane is called Re(max) (unit: nm), and the minimum value is called Re(min) (unit: nm)),
[Equation 4]
Deviation of in-plane phase difference on the TD side = Re(max)-Re(min)
(In Equation 4, for a rectangular specimen of 3 cm in the MD direction and 2 cm in the TD direction of the retardation film, five points are displayed at 0.3 cm intervals in the TD direction, and the in-plane retardation at a wavelength of 550 nm is measured at that point, and measured. The maximum value among the phase difference in one plane is called Re(max) (unit: nm), and the minimum value is called Re(min) (unit: nm)).
The retardation film of claim 1, wherein the retardation film satisfies Equation 1 and Equation 2 below:
[Equation 1]
0.7 ≤ Re(450)/Re(550) ≤ 0.9
[Equation 2]
1.0 <Re(650)/Re(550) ≤ 1.3
(In Equation 1 and Equation 2 above,
Re (450) is the in-plane retardation (unit: nm) at the wavelength of the retardation film at 450 nm, Re (550) is the in-plane retardation (unit: nm) at the wavelength of the retardation film (550 nm), and Re (650) is the in-plane at the wavelength of the retardation film 650 nm. Phase difference (unit: nm)).
delete The retardation film according to claim 1, wherein the retardation film is a two-component retardation film consisting only of a non-epoxy compound having the fluorene skeleton and the aromatic and aliphatic polycarbonate compounds as the base resin.
The method of claim 1, wherein the retardation film has a first glass transition temperature of 115° C. to 150° C. and a second glass transition temperature of 115° C. to 150° C., and the first glass transition temperature and the second glass transition temperature are The same or different ones, retardation film.
The retardation film according to claim 5, wherein a difference between the second glass transition temperature and the first glass transition temperature is 0°C to 10°C.
The retardation film of claim 1, wherein the retardation film is a non-epoxy single-layer retardation film.
The retardation film of claim 1, wherein the retardation film has a biaxial degree NZ of 0.95 to 1.05 at a wavelength of 550 nm.
The retardation film according to claim 1, wherein the non-epoxy time compound having a fluorene skeleton comprises a cardo-type polyester compound having a bisarylfluorene skeleton.
The retardation film according to claim 1, wherein the non-epoxy clock compound having a fluorene skeleton has a glass transition temperature of 115°C to 150°C.
The retardation film according to claim 1, wherein the aromatic and aliphatic polycarbonate compounds comprise a block-type polycarbonate resin in which aromatic units and aliphatic units are alternately arranged.
The retardation film according to claim 11, wherein the aromatic unit is a bisphenol-based, and the aliphatic unit contains a linear alkylene group.
The retardation film according to claim 1, wherein the aromatic-based and aliphatic polycarbonate compounds have a glass transition temperature of 115°C to 150°C.
The retardation film according to claim 1, wherein the difference between the glass transition temperature of the aromatic-based and aliphatic polycarbonate compounds and the glass transition temperature of the non-epoxy-based compound having the fluorene skeleton is 0°C to 10°C.
The method of claim 1, wherein the non-epoxy compound having a fluorene skeleton is 50 parts by weight to 99.9 parts by weight among a total of 100 parts by weight of the non-epoxy compound having a fluorene skeleton and the aromatic and aliphatic polycarbonate compounds. , The aromatic-based and aliphatic polycarbonate compound is contained in an amount of 0.1 parts by weight to 50 parts by weight, a retardation film.
The retardation film according to claim 1, wherein the retardation film further comprises rod-shaped nanoparticles.
Polarizing film; And the retardation film of any one of claims 1, 2, and 4 to 16 formed on one surface of the polarizing film.
The polarizing plate of claim 17, wherein a positive C plate is further laminated on one surface of the retardation film.
A display device comprising the polarizing plate of claim 17.