KR20150145610A - Optical filter for stereoscopic display device and manufacturing method for the same - Google Patents

Abstract

The present invention relates to an optical filter for stereoscopic display device and a method for manufacturing the same. The optical filter includes a base film which satisfies equation (1) : 0nm <= Rin 50nm and (2) 0nm <= Rth<= 100nm; and a 3D filter layer which is formed on the base film and includes a first region and a second region which have different phase delay characteristics. In the equation, the Rin is the surface direction phase difference value of the base film measured in 550nm wavelength, and the Rth is the thickness direction phase difference value of the base film measured in 550nm wavelength.

Description

TECHNICAL FIELD [0001] The present invention relates to an optical filter for a stereoscopic image display device,

The present invention relates to an optical filter for a stereoscopic image display device and a method of manufacturing the same.

A stereoscopic image display device is a new concept image display device which improves the quality level of visual information by several dimensions by providing a three-dimensional image similar to a real image that a person sees and felt unlike a conventional two-dimensional plane image. In this case, the stereoscopic image display device can be roughly divided into a method using polarized glasses and a method using no polarized glasses. Among them, the stereoscopic image display device using the polarizing glasses is different from the left- And a polarizing plate or the like is attached to the polarizing glasses so that only the left eye image is seen through the left eye lens and only the right eye image is seen through the right eye lens.

The stereoscopic image display apparatus of the polarizing glasses system includes an image generating section including a left eye image section for generating a left eye image and a right eye image section for generating a right eye image, And a filter unit for changing the polarization state of the right eye image light. At this time, the filter unit comprises a 3D filter layer patterned to correspond to the left-eye image display unit and the right-eye image display unit, and a base layer supporting the 3D filter layer. As the base layer, TAC (TriAcetyl Cellulose, triacetylcellulose) have.

However, in the conventional stereoscopic image display device using the TAC film as the base layer of the filter portion as described above, there is a limitation in realizing a wide 3D viewing angle only by the above configuration, and therefore, a separate retardation film must be provided There was a problem.

An object of the present invention is to provide an optical filter for a stereoscopic image display device and a method of manufacturing the stereoscopic image display device, which can realize a wide 3D viewing angle characteristic without applying a separate retardation film.

In one aspect, the present invention relates to a base film satisfying the following formulas (1) and (2); And a 3D filter layer formed on the base film and including a first region and a second region having different phase delay characteristics from each other.

(1): 0 nm? R _in ? 50 nm

(2): 0 nm? R _th ? 100 nm

In the above formulas (1) and (2)

R _in is the retardation value in the plane direction of the base film measured at a wavelength of 550 nm,

R _th is the retardation value in the thickness direction of the base film measured at a wavelength of 550 nm.

On the other hand, it is preferable that the base film satisfies the following formula (3).

(3): T _{380 nm} ? 10%

In the above formula (3)

T _{380 nm} is the light transmittance of the base film at a wavelength of 380 nm.

On the other hand, the base film preferably has a moisture permeability of 150 g / m ² · day or less.

On the other hand, the base film preferably includes an acrylic resin and a polymer material having negative retardation characteristics.

At this time, the acrylic resin may include an acrylic monomer; And at least one monomer selected from the group consisting of styrene-based monomers, maleic anhydride-based monomers and maleimide-based monomers.

The polymer material having negative phase retardation may be at least one selected from the group consisting of styrene resins, polyvinylcarbazole, and polyvinylnaphthalene.

On the other hand, the acrylic resin and the polymer material having negative retardation characteristics are preferably contained in a weight ratio of 95: 5 to 50:50.

On the other hand, the base film preferably further comprises a triazine-based ultraviolet screening agent or a benzotriazole-based ultraviolet ray absorbing agent.

On the other hand, the base film preferably further comprises a light stabilizer.

The 3D filter layer may include an orientation layer patterned to have a first region for controlling the polarization state of the right eye image and a second region for controlling the polarization state of the left eye image to have different retardation values; And a liquid crystal layer formed on the alignment layer.

The present invention also provides a stereoscopic image display device including the optical filter.

In another aspect, the present invention provides a method of manufacturing a semiconductor device, comprising: preparing a base film satisfying the following formulas (1) and (2); And forming a 3D filter layer on at least one side of the base film, the 3D filter including a first region and a second region having different retardation characteristics from each other.

(1): 0 nm? R _in ? 50 nm

(2): 0 nm? R _th ? 100 nm

In the above formulas (1) and (2)

R _in is the retardation value in the plane direction of the base film measured at a wavelength of 550 nm,

R _th is the retardation value in the thickness direction of the base film measured at a wavelength of 550 nm.

On the other hand, it is preferable that the step of producing the base film is performed such that the base film further satisfies the following formula (3).

(3): T _{380 nm} ? 10%

In the above formula (3)

T _{380 nm} is the light transmittance of the base film at a wavelength of 380 nm.

In addition, it is preferable that the step of preparing the base film is performed such that the moisture permeability of the base film is 150 g / m ² · day or less.

Meanwhile, the step of preparing the base film is preferably performed by preparing an unoriented base film containing an acrylic resin and a polymer material having negative retardation characteristics, and then biaxially stretching the base film.

Since the base film of the optical filter of the present invention satisfies the above-mentioned expressions (1) and (2), a wide 3D viewing angle characteristic can be imparted to the stereoscopic image display device without using a separate retardation film.

On the other hand, it is more preferable that the base film of the optical filter of the present invention satisfies the above formula (3). In this case, ultraviolet rays can be effectively blocked without any additional treatment.

The base film of the optical filter of the present invention is more preferably low in moisture permeability. In this case, since the amount of dimensional change due to moisture is smaller than that of the conventional TAC film, the film is less deformed under heat and humidity conditions, It is possible to effectively prevent water from penetrating into the polarizing element without any special treatment.

1 is a cross-sectional view showing an example of an optical filter of the present invention.
FIG. 2 is a diagram showing the white luminance and the black luminance of the optical filter of the embodiment measured and their ratios in hue. FIG.
3 is a graph showing the white luminance and the black luminance of the optical filter of the comparative example measured and their ratios in hue.
4 is a light spectrum showing the light transmittance of the base film used in the examples.

First, terms used in this specification are defined.

(1) R _in means a retardation value _in the plane direction, which is obtained from the retardation value R _in = (n _x -n _y ) x d. Here, n _x is the refractive index in the direction in which the refractive index in the plane direction is the maximum (that is, in the slow axis direction), and n _y is the refractive index in the direction perpendicular to the slow axis in the plane direction d is the thickness of the film to measure the retardation value. On the other hand, _in the R it can be measured by a known method known in the art and, for example, can be measured using the equipment of Axoscan Axomatrics社.

(2) _Rth means a retardation value in the thickness direction, and is obtained by the retardation value in the thickness direction R _th = (n _z -n _y ) x d. In this case, n _y is the refractive index in the direction perpendicular to the slow axis in the plane direction (i.e., the fast axis direction), n _z is the refractive index in the thickness direction, and d is the thickness of the film to be measured. On the other hand, the R _th can be determined by well-known methods known in the art and, for example, can be measured using the equipment of Axoscan Axomatrics社.

(3) T ₃₈₀ nm means the light transmittance (%) of the base film measured with light having a wavelength of ₃₈₀ nm. At this time, the light transmittance is an actually measured value of a film actually manufactured, not a conversion value. Meanwhile, the T _{380 nm} can be measured by a well-known method well known in the art and can be measured using, for example, a U-3310 spectrometer manufactured by Hitachi.

(4) "positive retardation property" means that the maximum refractive index is expressed along the stretching direction at the time of stretching, and "negative retardation property" means that the maximum refractive index is expressed along the direction perpendicular to the stretching direction at the time of stretching do.

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

<< Optical filter >>

First, an optical filter for a stereoscopic image display device of the present invention will be described.

The optical filter for a stereoscopic image display device of the present invention comprises a base film (100); And a 3D filter layer 200 formed on the base film and including a first region and a second region having different phase delay characteristics from each other.

1. Base film

First, the base film is basically used to support the 3D filter layer, and further satisfies the following formulas (1) and (2). When the base film satisfies the following formulas (1) and (2), it is possible to secure a wide 3D viewing angle of the stereoscopic image display device without providing a separate retardation film. On the other hand, the base film preferably has a retardation value in the range of 0 to 40 nm, 0 to 20 nm, or 0 to 10 nm, more preferably 30 to 90 nm, 40 to 80 nm, or 60 nm And more preferably about 80 nm to about 80 nm. In this case, the above-mentioned viewing angle improving effect is more excellent.

(1): 0 nm? R _in ? 50 nm

(2): 0 nm? R _th ? 100 nm

In the above formulas (1) and (2), R _in is the retardation value in the plane direction of the base film measured at a wavelength of 550 nm, and R _th is the retardation value in the thickness direction of the base film measured at a wavelength of 550 nm.

On the other hand, it is more preferable that the base film satisfies the following formula (3). In this case, the ultraviolet rays can be effectively blocked by only the optical filter of the present invention without any special process. On the other hand, it is more preferable that the base film has a light transmittance of 8% or less at a wavelength of 380 nm. This is because the ultraviolet shielding effect described above is more excellent.

(3): T _{380 nm} ? 10%

In the above formula (3), T _{380 nm} is the light transmittance of the base film at a wavelength of 380 nm.

The base film of the optical filter of the present invention which satisfies the above-mentioned expressions (1) to (2) and preferably satisfies the expression (3) can also be produced by suitably controlling the raw material and stretching conditions.

Specifically, the base film may include an acrylic resin and a polymer material having negative retardation characteristics. In the case of using the acrylic resin as described above, the amount of dimensional change due to moisture is small compared with the conventional case where the TAC film is used as a base film, the film is less deformed under heat and humidity conditions, It is possible to effectively prevent moisture from penetrating into the polarizing element without using the polarizing plate. In addition, by using the acrylic resin in combination with a polymer material having negative retardation characteristics, the above equations (1) and (2) can be satisfactorily satisfied by stretching.

The acrylic resin includes a (meth) acrylic monomer as a main component, and includes not only a homopolymer resin composed of a (meth) acrylic monomer but also a copolymer resin in which a monomer other than a (meth) acrylic monomer is copolymerized.

On the other hand, the (meth) acrylic monomers include not only acrylates and methacrylates but also derivatives of acrylates and methacrylates, such as methyl methacrylate, ethyl methacrylate, propyl methacrylate, n -butyl Methacrylate, t -butyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, benzyl methacrylate, methoxyethyl methacrylate, ethoxyethyl methacrylate, butoxy methyl methacrylate, Acrylates such as ethyl acrylate, propyl acrylate, n -butyl acrylate, t -butyl acrylate, cyclohexyl acrylate, phenyl acrylate, benzyl acrylate, methoxyethyl acrylate, ethoxyethyl acrylate, Acrylate, oligomers thereof, etc. Among them, Methacrylate, one or more preferably alkyl (meth) acrylates such as methyl acrylate, is not limited thereto. These may be used alone or in combination.

On the other hand, in order to improve the heat resistance, the acrylic resin can be produced by copolymerizing a maleic anhydride monomer, a maleimide monomer, etc. with other monomers other than the (meth) acrylic monomers. Among them, it is more preferable to include a maleic anhydride-based monomer or a maleimide-based monomer. Examples of the maleic anhydride monomer include maleic anhydride, methyl maleic anhydride, ethyl maleic anhydride, propyl maleic anhydride, isopropyl maleic anhydride, cyclohexyl maleic anhydride and phenyl maleic anhydride. ; Examples of the maleimide-based monomer include maleimide, N-methylmaleimide, N-ethylmaleimide, N-propylmaleimide, N-isopropylmaleimide, N-cyclohexylmaleimide, But are not limited thereto. These may be used alone or in combination.

On the other hand, in order to further improve the negative retardation property, the acrylic resin may be produced by copolymerizing a styrene monomer together with a monomer other than the (meth) acrylic monomer. Although not limited thereto, it is more preferable to use styrene or? -Methylstyrene among styrene-based monomers. These may be used alone or in combination.

On the other hand, the acrylic resin may be used in combination with (meth) acrylic monomers by mixing two or more kinds of styrenic monomers, maleic anhydride monomers, maleimide monomers, and the like. For example, the acrylic resin may be a (meth) acrylic monomer; And at least one monomer selected from the group consisting of styrene-based monomers, maleic anhydride-based monomers and maleimide-based monomers.

More specifically, the acrylic resin includes, but is not limited to, cyclohexyl maleic anhydride-methyl methacrylate copolymer, N-cyclohexyl maleimide-methyl methacrylate copolymer, styrene-cyclohexyl maleic anhydride- Methyl methacrylate copolymer, styrene-N-cyclohexylmaleimide-methylmethacrylate copolymer,? -Methylstyrene-N-cyclohexylmaleimide-methylmethacrylate copolymer,? Methylstyrene-N-phenylmaleimide Methyl methacrylate copolymer,? -Methylstyrene-N-phenylmaleimide-methylmethacrylate-methacrylate copolymer,? -Methylstyrene-N-cyclohexylmaleimide-methylmethacrylate-cyclohexyl Methacrylate copolymer and the like.

The polymer material having the negative retardation characteristic is not limited as long as it is a polymer material having a negative retardation characteristic. However, from the viewpoint of compatibility with an acrylic resin, a styrene resin, polyvinylcarbazole, polyvinylnaphthalene or the like can be preferably used.

On the other hand, the styrenic resin can be used without particular limitation as long as it contains a styrene-based monomer as a main component. Examples of the styrenic monomer include but are not limited to styrene,? -Methylstyrene, 3-methylstyrene, 4-methylstyrene, 2,4-dimethylstyrene, 2,5-dimethylstyrene, ? -Methylstyrene, 4-fluoro-? -Methylstyrene, 4-chlorostyrene, 2,4,6-trimethylstyrene, cis-? -Methylstyrene, trans-? methylstyrene, 4-t-butylstyrene, 2-fluorostyrene, 3-fluorostyrene, 4-fluorostyrene, 2,4-difluorostyrene, 2,3 , 4,5,6-pentafluorostyrene, 2-chlorostyrene, 3-chlorostyrene, 4-chlorostyrene, 2,4-dichlorostyrene, 2,6-dichlorostyrene, octachlorostyrene, , 3-bromostyrene, 4-bromostyrene, 2,4-dibromostyrene,? -Bromostyrene,? -Bromostyrene, 2-hydroxystyrene and 4-hydroxystyrene. Among them, And more preferably in the α- methyl styrene. These may be used alone or in combination.

In addition to the above styrene type monomer, the styrene type resin may also be used in combination with a styrene type monomer in combination of two or more kinds of maleic anhydride type monomer, maleimide type monomer, acrylonitrile type monomer and the like. For example, the styrene-based resin includes styrene-based monomers; And at least one monomer selected from the group consisting of maleic anhydride-based monomer, maleimide-based monomer and acrylonitrile-based monomer.

Examples of the maleic anhydride monomer include maleic anhydride, methyl maleic anhydride, ethyl maleic anhydride, propyl maleic anhydride, isopropyl maleic anhydride, cyclohexyl maleic anhydride and phenyl maleic anhydride. Can be; Examples of the maleimide-based monomer include maleimide, N-methylmaleimide, N-ethylmaleimide, N-propylmaleimide, N-isopropylmaleimide, N-cyclohexylmaleimide, For example; Examples of the acrylonitrile-based monomer include acrylonitrile, methacrylonitrile, ethacrylonitrile, and phenyl acrylonitrile. However, the present invention is not limited thereto.

More specifically, the styrenic resin includes, but is not limited to, styrene-maleic anhydride copolymer, styrene-acrylonitrile copolymer,? -Methylstyrene-acrylonitrile copolymer, N-phenylmaleimide-? -Methylstyrene-acrylonitrile copolymer, N-phenylmaleimide-styrene-acrylonitrile copolymer, N-phenylmaleimide-a-methylstyrene-acrylonitrile and the like.

In addition, the polyvinylcarbazole has a carbazole skeleton in the molecule such as poly (9-vinylcarbazole), and polyvinylcarbazole generally used in the art can be used without any particular limitation.

The polyvinylnaphthalene has a naphthalene skeleton in the molecule such as poly (2-vinylnaphthalene), and polyvinylnaphthalene generally used in the art can be used without particular limitation.

On the other hand, the acrylic resin and the polymer material having negative retardation characteristics are preferably contained in a weight ratio of 95: 5 to 50:50. If the polymer material having a negative retardation characteristic is included in the range of less than the above range, there may arise a problem that the retardation characteristic is deteriorated. In addition, when the amount is larger than the above range, the glass transition temperature of the mixed resin may be lowered and the heat resistance may be lowered. Also, the phase difference developing property becomes too large and the film must be excessively thin The handling may become difficult.

On the other hand, the base film preferably further comprises an ultraviolet screening agent. In this case, it is possible to realize an excellent ultraviolet shielding effect as described above. At this time, the ultraviolet absorber used in the present invention is included in order to effectively block ultraviolet rays introduced from the outside, and can be used without any particular limitation as long as it is an ultraviolet absorber capable of setting a light transmittance within 10% at a wavelength of 380 nm. Examples of the ultraviolet absorber include benzophenone ultraviolet absorbers, benzotriazole ultraviolet absorbers, triazine ultraviolet absorbers, salicylate ultraviolet absorbers, and the like, which are well known in the art.

On the other hand, the ultraviolet absorber is not particularly limited, but is preferably a triazine ultraviolet absorber or a benzotriazole ultraviolet absorber. In this case, the thermal stability and the ultraviolet ray absorbing effect are excellent, and a sufficient amount of ultraviolet ray shielding effect can be obtained even in an appropriate amount. Further, fume phenomenon and migration phenomenon that may occur during the film formation process can be prevented .

On the other hand, the triazine-based ultraviolet absorber usable in the present invention is not particularly limited and includes, for example, a compound having a 2,4,6-triphenyl-1,3,5-triazine skeleton as a main component, Various triazine-based ultraviolet absorbers available in the art can be used without particular limitation.

More specifically, for example, the triazine-based ultraviolet absorber may include, but is not limited to, a triazine-based compound represented by the following general formula (1) or (2).

[Chemical Formula 1]

In Formula _1, R 1 ~ R ₃ are each independently a substituted or unsubstituted C _{1 ~ 18} alkyl or hydrogen. In this case, R ₁ to R ₃ may be substituted with an alkyl group, an alkoxy group, a hydroxyl group, a halogen atom, or may be interrupted by an oxygen atom, a sulfur atom, a carbonyl group, an ester group, an amide group or an imino group. The above substitution and termination may be combined.

(2)

In Formula 2, R ₄ ~ R ₆ are each independently a substituted or unsubstituted C _{1 ~ 18} alkyl or hydrogen, R ₇ ~ R ₉ are each independently a substituted or unsubstituted C _{1 ~ 6} alkyl or hydrogen ring . Here, R ₄ to R ₉ may be substituted with an alkyl group, an alkoxy group, a hydroxyl group, a halogen atom, or may be interrupted by an oxygen atom, a sulfur atom, a carbonyl group, an ester group, an amide group or an imino group. The above substitution and termination may be combined.

On the other hand, R ₁ ~ R ₃ of Formula 1 are identical C _{3 ~ 5} alkyl, such as all profiles to each other, or both n- butyl, or it is more preferable that both n- pentyl. In this case, ultraviolet rays in the UVB region can also be effectively blocked. For example, although not limited thereto, the triazine-based compound represented by Formula 1 may preferably be a triazine-based compound represented by Formula 1-1.

[Formula 1-1]

Further, in the above formula (2) R ₄ R ~ ₆ are identical C _{4 ~ 8} alkyl, such as n- butyl both with each other, or both n- pentyl, n- hexyl, or both, or both n- heptyl, n- octyl are both is more preferable, and the above formula (2) of the R ₇ R ~ ₉ are identical to each other or C _{1 ~ 3} alkyl, such as both methyl, are both more preferably ethyl or, or both profiles. In this case, a better ultraviolet shielding effect can be obtained. For example, although not limited thereto, the triazine-based compound represented by Formula 2 may preferably be a triazine-based compound represented by Formula 2-1.

[Formula 2-1]

Also, the benzotriazole-based ultraviolet absorber usable in the present invention is not particularly limited, and includes, for example, a compound having a (2H-benzotriazol-2-yl) phenol skeleton as a main component, Various commercially available ultraviolet absorbers based on benzotriazole can be used without particular limitation.

More specifically, for example, the benzotriazole ultraviolet absorber may include, but is not limited to, a benzotriazole-based compound represented by the following formula (3).

(3)

In Formula 3, R ₁₀ ~ R ₁₁ are each independently a substituted or unsubstituted C _{1 ~ 18} alkyl or hydrogen, R ₁₂ is a substituted or unsubstituted C _{1 ~ 6} alkylene. Here, R ₁₀ to R ₁₂ may be substituted with an alkyl group, an alkoxy group, a hydroxyl group, a halogen atom, or may be interrupted by an oxygen atom, a sulfur atom, a carbonyl group, an ester group, an amide group or an imino group. The above substitution and termination may be combined.

R ₁₀ to R ₁₁ in the general formula (3) are the same C _{4 to 10} alkyl, for example, all 1,1,3,3-tetramethyl-butyl, or more preferably a tert-butyl group. Further, R ₁₂ in the formula (3) is more preferably a C _{1 ~ 3} alkylene, such as methylene, dimethylene, dimethylmethylene or the like. In this case, there is an advantage that the thermal stability is excellent. For example, but not limited to, the benzotriazole-based compound represented by Formula 3 may be a benzotriazole-based compound represented by Formula 3-1.

[Formula 3-1]

On the other hand, the base film of the present invention may further contain a light stabilizer if necessary. In this case, there is an advantage that the optical spectrum can be stabilized even when the base film is exposed to ultraviolet rays for a long period of time. In this case, the light stabilizer is not particularly limited, and for example, a piperidine light stabilizer (HALS), a sulfur / phosphorus light stabilizer, and the like well known in the art can be used without particular limitation.

More specifically, examples of the piperidine-based light stabilizer (HALS) include SABOSTAB UV62, UV94, UV119 available from Songwon Industrial Co., Ltd., LA 63 and LA 68 manufactured by ADEKA, Tinuvin 770 manufactured by BASF, As the sulfur / phosphorus-based light stabilizer, for example, IR1010 available from BASF Co., which is commercially available, may be used.

On the other hand, the base film preferably has a moisture permeability of 150 g / m ² · day or less, for example, 0.1 to 130 or 0.1 to 110 g / m ² · day. In this case, as described above, since the amount of dimensional change due to moisture is smaller than that of the conventional TAC film, the film is less deformed under heat and humidity conditions, and when it is attached to a polarizing plate or the like, moisture penetrates into the polarizing element Can be effectively prevented. The method of measuring the moisture permeability is not particularly limited, and can be measured by, for example, a method of measuring the weight of water permeating the film for one day under conditions of a temperature of 40 DEG C and a relative humidity of 90%.

2. 3D filter layer

The 3D filter layer is for realizing a stereoscopic image by differentiating the polarization states of the right eye image light and the left eye image light and may include a first region and a second region having different phase delay characteristics, Various 3D filter layers commonly used in the art can be used without any particular limitation. For example, the 3D filter layer may include an orientation layer patterned so that a first region for controlling a polarization state of a right eye image and a second region for controlling a polarization state of a left eye image have different phase difference values; And a liquid crystal layer formed on the alignment layer.

At this time, the composition for forming an alignment layer for forming the alignment layer is not particularly limited, and a composition containing a known photo-alignment material may be used. The liquid crystal compound for forming the liquid crystal layer is not particularly limited, and a known liquid crystal compound can be used.

<< Manufacturing method of optical filter >>

Next, a manufacturing method of the optical filter for the stereoscopic image display device of the present invention will be described.

A manufacturing method of an optical filter for a stereoscopic image display device according to the present invention comprises the steps of: preparing a base film satisfying the above-mentioned formulas (1) and (2); And forming a 3D filter layer on at least one surface of the base film, the 3D filter layer including a first region and a second region having different phase delay characteristics from each other. At this time, it is more preferable that the preparation method is carried out such that the base film is also satisfactorily satisfied with the formula (3), and the water vapor permeability of the base film is 150 g / m ² · day or less.

1. Base Film Production Step

First, the base film of the present invention satisfying the above-mentioned formulas (1) and (2) can be produced by using a resin composition comprising the above-mentioned acrylic resin and a polymer material having negative retardation characteristics, For example, an unoriented film may be prepared by extrusion molding, solution casting, calender molding, film casting, or the like, followed by stretching.

On the other hand, the resin composition for producing the unstretched film may further contain an ultraviolet absorber as described above. In this case, the base film to be produced may satisfy the formula (3).

In addition, the resin composition for preparing the unstretched film may further contain a light stabilizer as described above. In this case, even when the substrate film is exposed to ultraviolet rays for a long time, it can have a stable optical spectrum.

On the other hand, it is preferable that the unstretched film is stretched by biaxial stretching. In this case, the biaxial stretching can be performed by a method of uniaxially stretching the unstretched base film in the longitudinal direction (MD) and then uniaxially stretching in the width direction (TD), or by uniaxially stretching in the longitudinal direction (MD) and the transverse direction It is possible to simultaneously stretch biaxially.

Specifically, the stretching is performed by uniaxially stretching the base film in a longitudinal direction (MD) at a magnification ratio of 1.1 to 4.0, more preferably at a magnification ratio of 1.3 to 3.0, and then stretching the base film at a magnification ratio of 1.1 to 4.0 in a width direction (TD) And may be uniaxially stretched at a magnification ratio of 1.3 to 3.0. Alternatively, the stretching may be simultaneous biaxial stretching independently in the longitudinal direction (MD) and the transverse direction (TD) at a magnification of 1.1 to 4.0, more preferably 1.3 to 3.0. If the stretching ratio is less than the above range, the toughness of the film may deteriorate, so that it may be difficult to apply the prepared base film to the base film of the optical filter. If the stretching ratio exceeds the above range, And stable film production may be difficult.

The stretching is preferably performed by stretching the base film so that the base film has a thickness of 5 to 80 占 퐉. For example, the base film may be stretched to have a thickness of 10 to 70 占 퐉 or 15 to 65 占 퐉 . If the thickness of the base film after stretching is less than the above range, the thickness of the film may become too thin, which may result in poor handling, and may cause breakage or breakage during the manufacturing process or handling of the product. There is a difficulty in thinning, and further, it may be difficult to express a desired phase difference.

The stretching is preferably performed at a temperature of (Tg-20) ° C to (Tg + 30) ° C, more preferably in a range of (Tg) ° C to Tg + 25) ° C or (Tg) ° C to (Tg + 20) ° C. At this time, when the stretching step is performed at a temperature lower than the above range, the storage elastic modulus of the film may be lowered, so that the loss elastic modulus may become larger than the storage elastic modulus. In addition, when the polymerization is carried out at a temperature exceeding the above range, the orientation of the polymer chains may be relaxed and lost. On the other hand, the glass transition temperature can be measured by a differential scanning calorimeter (DSC). For example, in the case of using a differential scanning calorimeter (DSC), when a sample of about 10 mg is sealed in a dedicated pan and heated at a constant temperature, the amount of endothermic heat The transition temperature can be measured.

On the other hand, the stretching method is not particularly limited, and can be carried out by a stretching method well known in the art. For example, in the stretching in the longitudinal direction (MD), a roll-to-roll stretching method, a compression stretching method, or the like can be used, and a tenter can be used for stretching in the width direction (TD). Further, simultaneous biaxial stretching in the longitudinal direction (MD) and the transverse direction (TD) can use a simultaneous biaxial stretching machine.

2. 3D filter layer manufacturing step

Next, after the base film is produced, a 3D filter layer including a first region and a second region having different phase delay characteristics from each other is formed on at least one surface of the base film. At this time, the method of forming the 3D filter layer is also not particularly limited, and can be formed by a method commonly used in the related art. For example, it can be produced by forming a patterned orientation layer on a base film, coating the liquid crystal on the orientation layer, and then curing it with ultraviolet rays or the like to fix the orientation of the liquid crystal.

In this case, the patterning of the alignment layer may be performed in various ways, for example, a method in which different alignment layers are alternately formed on the portions corresponding to the first region and the second region, And then an alignment layer is formed by superimposing only the portion corresponding to the second region on the alignment layer. Alternatively, an alignment layer may be formed on the entire surface of the base film, and then a first region and a second region Or a method of irradiating polarized light of different directions to the light emitting layer. A known photo-crosslinkable or photopolymerizable liquid crystal compound is applied and oriented on the patterned alignment layer formed by such methods, and the liquid crystal compound is photo-crosslinked or photopolymerized to form a first region and a second region Can be implemented.

<< More >>

The optical filter of the present invention manufactured by the above method can be used for a stereoscopic image display device. At this time, as long as the stereoscopic image display device includes the optical filter, various methods known in the art can be applied.

Hereinafter, the present invention will be described in more detail with reference to Examples.

Example  One

(Styrene-acrylonitrile copolymer (LG Chemical, SAN82TR, acrylonitrile content: 20%) was mixed with an acrylic resin (poly (cyclohexylmaleimide-co-methylmethacrylate) % By weight) were mixed at a weight ratio of 87:13, 0.7 parts by weight of an ultraviolet screening agent (including a triazine-based compound represented by the following formula (4) as a main component) was added to the composition, and the mixture was extruded at 250 ° C. and 200 rpm To prepare a resin composition. An undrawn film having a width of 800 mm and a thickness of 185 占 퐉 was produced using the T-die film under the condition of 250 占 폚. The unstretched film was uniaxially stretched by a roll-to-roll method in a longitudinal direction at a temperature of 125 DEG C and stretched 2.2 times by a tenter stretching method at a temperature of 125 DEG C to stretch the biaxially stretched film .

[Chemical Formula 4]

The prepared biaxially stretched film was used as a base film, and a mixture of a polynorbornene and an acrylic monomer having a cinnamate group on one side was mixed with a photoinitiator (Igacure 907), and the mixture was further added to a toluene solvent with a solids concentration of polynorbornene To 2 wt%, the coating was coated to a thickness of about 1 mu m after drying and dried in an oven at 80 DEG C for 2 minutes. The dried composition for forming alignment layer was subjected to alignment treatment so that one region was alternately arranged adjacent to each other at a width of about 450 mu m so as to form an angle of 45 DEG in a clockwise direction and 45 DEG in a counterclockwise direction in another region And photo-alignment was performed using a pattern mask and ultraviolet rays.

Thereafter, a liquid crystal layer was formed so as to have the characteristic of the 1/4 wavelength layer on the alignment layer subjected to alignment treatment. Specifically, the liquid crystal composition includes a polyfunctional polymerizable liquid crystal compound represented by the following formula (5), and a liquid crystal composition containing a proper amount of a photo initiator is applied to a dry thickness of about 1 탆, And then irradiated with ultraviolet rays for about 10 seconds to crosslink and polymerize to form a liquid crystal layer having an optical axis perpendicular to each other in accordance with the orientation of the lower light alignment layer to produce an optical filter for a stereoscopic image display device.

[Chemical Formula 5]

Example  2

A biaxially stretched film was produced in the same manner as in Example 1 except that no ultraviolet screening agent was included. Thereafter, an optical filter was produced in the same manner.

Comparative Example

An optical filter was prepared in the same manner as in Example 1 except that a commercially available TAC film (Fuji, UZ-TAC) was used as a base film in place of the acrylic film thus prepared.

Experimental Example  One - Phase difference  Measure

The surface direction retardation value and the thickness direction retardation value at a wavelength of 550 nm of the base film used in Examples 1 to 2 and Comparative Examples were measured using Axoscan's Axoscan equipment and are shown in Table 1 below.

division

R _in (nm)
R _th (nm)
Example 1

+ 5
+ 70
Example 2

+ 7
+ 70
Comparative Example

+ 2
- 40

As shown in Table 1, in the case of Examples 1 and 2 using the base film according to the present invention, the retardation values in the plane direction of the base film were 5 nm and 7 nm, respectively, and the retardation values in the thickness direction were all 70 nm. 1) and (2). However, in the case of a conventional TAC film, it can be seen that the retardation value in the thickness direction is -40 nm, which does not have such a retardation property.

Experimental Example  2 - Moisture permeability  And dimensional change measurement

The dimensional changes of the substrate films used in Examples 1 to 2 and Comparative Examples according to the moisture permeability and humidity were measured and are shown in Table 2 below. The following water permeability was measured by measuring the weight of water permeating the film during a day under conditions of a temperature of 40 ° C and a relative humidity of 90%. The following dimensional change (CHE) was measured using a TA DMA machine at a predetermined temperature Were measured by the method of measuring the amount of change in dimension.

division

Moisture permeability
(g / m ² .day)
Dimensional change (ppm /% RH)

25 ° C, 30 to 75%

50 ° C, 30 to 75%
80 ° C, 30 to 75%
Example 1

42
29
54
98
Example 2

41
28
55
97
Comparative Example

262
67
95
138

As shown in Table 2, it can be seen that the base film according to the present invention has a very low moisture permeability compared to the conventional TAC retardation film, and the dimensional change according to the humidity is also small. Therefore, when the base film of the present invention is used, it can be seen that the film is less deformed under heat and humidity conditions than the conventional TAC film, and the moisture blocking effect is excellent.

Experimental Example  3 - Viewing angle measurement

The viewing angles of the optical filters of Example 1 and Comparative Example were measured using a measuring device (Eldim EZcontrast) and are shown in Figs. 2 and 3, respectively. Specifically, after the manufactured optical filter was applied to IPS-LCD having the first polarizing plate and the second polarizing plate attached to both sides of the liquid crystal panel, the white luminance and the black luminance at all the longitude and inclination angles were measured And the ratios thereof are shown in color in Fig. 2 and Fig. 3, respectively. In this case, the higher the contrast ratio, the reder the color, the lower the blue, and the wider the red area, the wider the viewing angle. Fig. 2 shows the results of Example 1, and Fig. 3 shows the results of Comparative Examples.

2 and 3, the optical filter of the present invention, which uses an acrylic film satisfying the above-mentioned expressions (1) and (2) as a base film, can be used as an optical filter of a comparative example using a conventional TAC film as a base film Contrast, and viewing angle of right and left are excellent.

Experimental Example  4 - Light transmittance measurement

In order to compare the ultraviolet blocking effect of Examples 1 and 2, an experiment for measuring the light transmittance at a wavelength of 380 nm was further performed. The results are shown in FIG. The light transmittance was measured using a U-3310 spectrometer from Hitachi.

As shown in FIG. 4, the light transmittance at 380 nm is about 5.3% in the case of Example 1 including the ultraviolet screening agent according to the present invention. Therefore, the formula (3) It has a blocking effect.

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, It will be obvious to those of ordinary skill in the art.

100: substrate film
200: 3D filter layer

Claims (15)

A base film satisfying the following formulas (1) and (2); And
And a 3D filter layer formed on the base film and including a first region and a second region having different phase delay characteristics from each other.
(1): 0 nm? R _in ? 50 nm
(2): 0 nm? R _th ? 100 nm
In the above formulas (1) and (2)
R _in is the retardation value in the plane direction of the base film measured at a wavelength of 550 nm,
R _th is the retardation value in the thickness direction of the base film measured at a wavelength of 550 nm.
The method according to claim 1,
Wherein the base film satisfies the following formula (3).
(3): T _{380 nm} ? 10%
In the above formula (3)
T _{380 nm} is the light transmittance of the base film at a wavelength of 380 nm.
The method according to claim 1,
Wherein the base film has a moisture permeability of 150 g / m ² · day or less.
The method according to claim 1,
Wherein the base film comprises an acrylic resin and a polymer material having negative retardation characteristics.
5. The method of claim 4,
The acrylic resin includes an acrylic monomer; And at least one monomer selected from the group consisting of styrene-based monomers, maleic anhydride-based monomers, and maleimide-based monomers.
5. The method of claim 4,
Wherein the polymer material having a negative retardation characteristic is at least one selected from the group consisting of a styrene resin, polyvinylcarbazole, and polyvinylnaphthalene.
5. The method of claim 4,
Wherein the acrylic resin and the polymer material having negative retardation characteristics are contained in a weight ratio of 95: 5 to 50:50.
5. The method of claim 4,
Wherein the base film further comprises a triazine-based ultraviolet screening agent or a benzotriazole-based ultraviolet screening agent.
5. The method of claim 4,
Wherein the base film further comprises a light stabilizer.
The method according to claim 1,
Wherein the 3D filter layer is formed by patterning a first region for controlling a polarization state of a right eye image and a second region for controlling a polarization state of a left eye image to have different retardation values; And a liquid crystal layer formed on the alignment layer.
A stereoscopic image display device comprising the optical filter according to any one of claims 1 to 10.
Preparing a base film satisfying the following formulas (1) and (2); And
And forming a 3D filter layer on at least one side of the base film, the 3D filter including a first region and a second region having different retardation characteristics from each other.
(1): 0 nm? R _in ? 50 nm
(2): 0 nm? R _th ? 100 nm
In the above formulas (1) and (2)
R _in is the retardation value in the plane direction of the base film measured at a wavelength of 550 nm,
R _th is the retardation value in the thickness direction of the base film measured at a wavelength of 550 nm.
13. The method of claim 12,
Wherein the step of preparing the base film is performed such that the base film satisfies the following formula (3) more satisfactorily.
(3): T _{380 nm} ? 10%
In the above formula (3)
T _{380 nm} is the light transmittance of the base film at a wavelength of 380 nm.
13. The method of claim 12,
Wherein the step of preparing the base film is performed so that the moisture permeability of the base film is 150 g / m ² · day or less.
13. The method of claim 12,
Wherein the step of preparing the base film is performed by a method of producing an unstretched base film containing an acrylic resin and a polymer material having negative retardation characteristics and then biaxially stretching the base film. .

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