WO2019045300A1 - Optical film having improved contrast ratio, polarizing plate including same, and liquid crystal display device including same - Google Patents

Abstract

Disclosed is an invention related to an optical film having an improved contrast ratio, a polarizing plate including same, and a liquid crystal display device including same. The optical film having an improved contrast ratio includes a protection layer and a pattern layer disposed on the protection layer, the pattern layer includes an embossed optical pattern on one surface thereof and a pattern part including a flat portion between the embossed optical pattern and another adjacent embossed optical pattern, the optical pattern has a base angle (θ) of about 55° to about 90°, and the pattern part satisfies equation 1 and further includes a gap fill layer that directly contacts the one surface of the pattern layer. (Equation 1 is defined in the specification.)

Description

Contrast improvement optical film, polarizing plate including the same, and liquid crystal display device including the same

The present invention relates to an optical film for improving contrast ratio, a polarizing plate including the optical film, and a liquid crystal display including the same.

The liquid crystal display apparatus is operated by emitting light from the backlight unit through the two polarizing plates. Therefore, although the color of the front of the screen of the liquid crystal display device is good, the color contrast, the contrast ratio, and the viewing angle of the front side of the liquid crystal display device may be lowered.

In order to increase the color, contrast, and viewing angle on the side, it is attempted to improve through the change of the liquid crystal panel or the liquid crystal structure. However, improvement through the modification of the liquid crystal panel is limited, and the process is complicated. As the size of the liquid crystal display increases, the disadvantage that the viewing angle becomes narrower in the case of the VA system is emphasized. To solve this problem, when the pattern structure having the internal diffusion is inserted, the viewing angle is widened and the visibility is improved.

A viewing angle can be improved by incorporating an optical film for improving the contrast ratio in the viewer-side polarizing plate. Further, an antiglare effect against external light can be obtained by laminating an optical film for improving contrast ratio in a polarizing plate and laminating an anti-glare film having surface irregularities on the contrast improving optical film. Conventional antiglare films are composed of a matrix for forming a film and antiglare particles dispersed in the matrix, for example, beads. The refractive index between the matrix and the antiglare particles is used to control the internal haze and the external haze, Scattering can be realized.

However, when the antiglare film is laminated on the contrast improving optical film, the effect of improving the contrast due to the optical film can be further reduced due to internal diffusion while passing through the antiglare film. In addition, the polarizing plate can be made thick by including a protective layer (base layer) for the antiglare film and a protective layer (base layer) for the contrast ratio improving optical film in total.

The background art of the present invention is disclosed in Japanese Laid-Open Patent Publication No. 2006-251659.

An object of the present invention is to provide an optical film with improved contrast ratio that can obtain external light scattering effect by particles while maintaining the effect of improving the front and side visibility due to the pattern layer and the gap fill layer.

Another object of the present invention is to provide a contrast ratio improving optical film which does not cause moiré even though it contains a pattern layer and an antiglare particle.

Another object of the present invention is to provide an optical film with improved contrast ratio that can be thinned.

The contrast improving optical film of the present invention includes a protective layer and a pattern layer formed on the protective layer, wherein the pattern layer is formed between the optical pattern of the embossed pattern on one side and the optical pattern of the embossed pattern immediately adjacent to the embossed optical pattern Wherein the optical pattern has a base angle &thetas; of about 55 DEG to about 90 DEG, the pattern portion satisfies the following formula (1)

<Formula 1>

About 1 < P / W &lt; / = about 10

(In the above formula (1), P is the period (unit: mu m) of the pattern portion,

W is the maximum width (unit: 占 퐉) of the optical pattern)

Further comprising a gap fill layer directly contacting one surface of the pattern layer,

Wherein the gap fill layer comprises a matrix and first particles included in the matrix, wherein an absolute value of a difference in refractive index between the matrix and the first particle is about 0 to about 0.03, and a refractive index of the pattern layer and the gap fill layer The difference can be at least about 0.06.

In an embodiment, the gap fill layer may include irregularities having a height of less than about 1% and less than about 20% of the first particle diameter.

In an embodiment, the maximum distance between the top surface of the pattern layer and the top surface of the gap fill layer may be greater than about 0 탆 and less than about 15 탆.

In an embodiment, the average particle size of the first particles may be less than the width of the first surface, which is the top of the optical pattern of the emboss.

In an embodiment, the first particles may comprise from about 1% to about 50% by weight of the gap fill layer.

In an embodiment, the first particle may comprise an antiglare particle.

In an embodiment, the ratio (W / L) of the maximum width (W) of the optical pattern of the relief to the width (L) of the flat portion may be about 0.1 to about 3.

In an embodiment, the first particle may be formed of at least one of polymethylmethacrylate, polystyrene, a copolymer of polymethylmethacrylate and styrene.

In an embodiment, the pattern layer may be formed of a composition for a pattern layer containing an aromatic group-free resin, high-refractive-index inorganic particles.

In an embodiment, the relief optical pattern may comprise an optical pattern whose cross section is a trapezoid, a rectangle or a square.

In an embodiment, the refractive index of the pattern layer may be higher than the refractive index of the gap fill layer.

In an embodiment, the gap fill layer may further include a second particle having a refractive index higher than that of the first particle.

The polarizing plate of the present invention may include a polarizing film and the contrast improving optical film of the present invention formed on the polarizing film.

The liquid crystal display device of the present invention may include the polarizing plate of the present invention.

The present invention provides an optical film with improved contrast ratio that can obtain external light scattering effect by particles while maintaining the effect of improving the front and side visibility due to the pattern layer and the gap fill layer.

The present invention provides an optical film with improved contrast ratio that does not cause moiré even though it contains a pattern layer and antiglare particles.

The present invention provides an optical film with improved contrast ratio that can be thinned.

1 is a cross-sectional view of an optical film for improving contrast ratio according to an embodiment of the present invention.

2 is a cross-sectional view of a polarizer according to an embodiment of the present invention.

The present invention is not limited to the above embodiments and various changes and modifications may be made by those skilled in the art without departing from the scope of the present invention. The present invention may be embodied in many different forms and is not limited to the embodiments described herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and the same or similar components are denoted by the same reference numerals throughout the specification.

The terms "upper" and "lower" in this specification are defined with reference to the drawings, wherein "upper" may be changed to "lower", "lower" What is referred to as " on " may include not only superposition, but also intervening other structures in the middle. On the other hand, what is referred to as " directly on ", " directly above ", or " directly formed " or " directly contacting "

In the present specification, the terms "horizontal direction" and "vertical direction" mean the longitudinal direction and the unidirectional direction of the rectangular liquid crystal display screen, respectively. In the present specification, the terms "front" and "side" refer to the horizontal direction (φ, θ) by the spherical coordinate system, the front surface is (0 °, 0 °) (0 °, 90 °) and the right end point (0 °, 90 °), respectively.

As used herein, the term " top part " means the highest part of the optical pattern of the emboss.

As used herein, the term " aspect ratio " means the ratio of the maximum height to the maximum width of the optical pattern (maximum height / maximum width).

As used herein, the term " period " means a distance between neighboring optical patterns, for example, a sum of a maximum width of one optical pattern and a width of one flat portion immediately adjacent to the optical pattern.

In the present specification, the " retardation in the retardation direction (Re) " is a value at a wavelength of 550 nm and is represented by the following formula A:

<Formula A>

Re = (nx - ny) xd

(In the above formula A, nx and ny are the refractive indexes in the slow axis direction and the fast axis direction of the protective layer or the substrate layer at a wavelength of 550 nm, respectively, and d is the thickness (unit: nm) of the protective layer or base layer.

As used herein, " (meth) acrylic " means acrylic and / or methacrylic.

Hereinafter, an optical film for improving contrast ratio according to an embodiment of the present invention will be described with reference to FIG. 1 is a cross-sectional view of an optical film for improving contrast ratio according to an embodiment of the present invention.

1, the contrast improving optical film 10 includes a protective layer 100 and a pattern layer 210 formed on the protective layer 100. The optical film 10 has a gap (not shown) directly opposed to one surface of the pattern layer 210, And a fill fill layer 220.

Protective layer

The protective layer 100 may be formed on one surface of the pattern layer 210, that is, on the light incident surface, to support the pattern layer 210. In one embodiment, the protective layer is formed directly on the pattern layer, which can thin the contrast improving optical film. The " directly formed " means that no adhesive layer, adhesive layer, or laminating layer is interposed between the protective layer and the pattern layer. However, the present invention is not limited thereto.

The protective layer 100 may be optically transparent, and may include a light incident surface and a light exit surface facing the light incident surface. A pattern layer 210 is formed on the light exit surface of the protective layer 100. The protective layer 100 may have a total light transmittance of 90% or more, for example, 90% to 100% in the visible light region. It can be transmitted to the pattern layer without affecting the incident light in the above range.

The protective layer 100 may be a protective film type or a protective coating type.

When the protective layer is a protective film type, it may include an optically transparent resin film. The protective film may be formed by melting and extruding the resin. If necessary, a further stretching process may be added. The resin may include a cellulose ester-based resin including triacetyl cellulose (TAC), a cyclic polyolefin-based resin including amorphous cyclic polyolefin (COP), a polycarbonate-based resin, polyethylene terephthalate A polyacrylate resin including a polyether resin, a polyether sulfone resin, a polysulfone resin, a polyamide resin, a polyimide resin, a non-cyclic-polyolefin resin, a polymethylmethacrylate resin, A vinyl alcohol resin, a polyvinyl chloride resin, and a polyvinylidene chloride resin.

The protective film may be a non-stretched film, but may be a phase difference film or an isotropic optical film having a predetermined range of retardation by stretching the resin by a predetermined method. In one embodiment, the protective film may be an isotropic optical film having a Re of about 60 nm or less, specifically about 0 nm to about 60 nm, more specifically about 40 nm to about 60 nm. The viewing angle can be compensated in the above range to improve the image quality. The " isotropic optical film " means a film in which nx, ny, and nz are substantially the same, and the " substantially the same " includes not only completely identical cases but also cases including some errors. In other embodiments, the protective film may be a retardation film having a Re of about 60 nm or greater. For example, the protective film may have a Re of about 60 nm to about 350 nm. For example, the protective film may have a Re of at least about 8,000 nm, specifically at least about 10,000 nm, more specifically at least about 10,000 nm, more specifically from about 10,100 nm to about 30,000 nm, more specifically from about 10,100 nm to about 15,000 nm . In this range, it is possible to prevent rainbow stains from being visible, and the diffusion effect of light diffused through the contrast ratio improvement layer can be made larger.

The protective coating layer may be formed of an active energy ray-curable resin composition comprising 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 radically polymerizable curable compound, a urethane resin, and a silicone resin. The cationic polymerizable curable compound may be an epoxy compound having at least one epoxy group in the molecule, or an oxetane compound having at least one oxetane ring in the molecule. The epoxy compound may be at least one of a hydrogenated epoxy compound, a chained aliphatic epoxy compound, a cyclic aliphatic epoxy compound, and an aromatic epoxy compound.

The radical polymerizable curable compound can be obtained by reacting two or more (meth) acrylate monomers having at least one (meth) acryloyloxy group in the molecule, a compound having a functional group and at least two (meth) acryloyloxy (Meth) acrylate oligomer having a &lt; / RTI &gt; (Meth) acrylate monomers include monofunctional (meth) acrylate monomers having one (meth) acryloyloxy group in the molecule, difunctional (meth) acrylates having two (meth) acryloyloxy groups in the molecule (Meth) acrylate monomers having three or more (meth) acryloyloxy groups in the molecule. (Meth) acrylate oligomer may be a urethane (meth) acrylate oligomer, a polyester (meth) acrylate oligomer, an epoxy (meth) acrylate oligomer, or the like. The polymerization initiator can cure the active energy ray-curable compound. The polymerization initiator may include at least one of a photocationic initiator and a photosensitizer. Gwangyang ionic initiator and photosensitizer may be those conventionally known to those skilled in the art.

Preferably, the protective layer 100 may be a non-surface treated non-surface treated protective film type or a protective coating type. As will be described later, the contrast-improving optical film exhibits an antiglare effect of the gap fill layer, so there is no need to perform surface treatment on the protective layer, thereby improving the contrast ratio. The optical film production process can be simplified and the contrast ratio can be improved by the surface treatment. It may not affect the optical function of the optical system.

The protective layer 100 may have a refractive index of from about 1.4 to about 1.7, preferably from about 1.45 to about 1.65.

The thickness of the protective layer 100 is about 10 탆 to about 200 탆, specifically about 20 탆 to about 200 탆, for a protective film type, about 20 탆 to about 250 탆, preferably about 30 탆 to about 200 탆, And in the case of the protective coating layer type, about 5 탆 to about 50 탆. Can be used for the polarizer in the above range.

The protective layer 100 may be a single layer as shown in FIG. 1, or may have a multi-layer structure of two or more protective films or protective coating layers.

Pattern layer

The pattern layer 210 is formed on the light exit surface of the protective layer 100 and can emit light emitted from the protective layer 210. The pattern layer 210 has a flat portion 212 between a positive embossed optical pattern 211 and a positive embossed optical pattern 211 and an immediately adjacent positive optical pattern 211 on one side of the pattern layer 210 And may be a layer having a pattern portion. The pattern layer 210 has the pattern portion directly contacting the gap fill layer 220 on one side.

The optical pattern 211 may be an optical pattern composed of at least one inclined surface 213 in which a first surface 214 is formed at the top and connected to the first surface 214. The pattern portion satisfies the following expression (1), and the optical pattern (211) can have a base angle (?) Of about 55 to about 90 degrees. The base angle θ means an angle formed by the inclined plane 213 of the optical pattern 211 and the line of the maximum width W of the optical pattern 211 to about 55 ° to about 90 °. Here, the inclined surface 213 refers to an inclined surface directly connected to the flat portion 212 of the optical pattern 211. In the above range, the front contrast ratio and the side contrast ratio can be improved at the same time, the difference between the front contrast ratio and the side contrast ratio can be reduced, and the contrast ratio can be increased at the same side viewing angle and the same front viewing angle. Specifically, the base angle? May range from about 70 degrees to about 90 degrees, and P / W (the ratio of P to W) may be about 1.2 to about 8:

<Formula 1>

About 1 < P / W &lt; / = about 10

(In the above formula (1), P is the period (unit: mu m) of the pattern portion,

W is the maximum width of the optical pattern (unit: mu m)).

Fig. 1 shows a case in which both base angles [theta] of the optical pattern are the same. However, optical patterns different in base angle [theta] may be included in the scope of the present invention if the base angle is included in the above range of about 55 [deg.] To about 90 [deg.]. For example, the base angle &amp;thetas; is about 55 DEG, 56 DEG, 57 DEG, 58 DEG, 59 DEG, 60 DEG, 61 DEG, 62 DEG, 63 DEG, 64 DEG, 65 DEG, 66 DEG, 80, 81, 82, 83, 84, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 85 °, 86 °, 87 °, 88 °, 89 ° or 90 °. For example, the P / W may be about 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 3, 4, 5, 6, 7 or 8.

The optical pattern 211 may be an embossed optical pattern composed of at least one inclined surface 213 having a first surface 214 formed at the top and connected to the first surface 214. 1, the optical pattern 211 shows a trapezoidal optical pattern in which two adjacent inclined surfaces 213 are connected by the first surface 214. However, the present invention is not limited to this, and the optical pattern may have a trapezoidal cross- But may be a rectangular or square optical pattern.

The first surface 214 is formed at the top so that the light reaching the pattern layer 210 in the optical display device is further diffused by the first surface 214, thereby increasing the viewing angle and brightness. Therefore, the light diffusion effect can be enhanced and the luminance loss can be minimized. The first surface 214 may be a flat surface to facilitate the process of producing the contrast ratio improving optical film. However, the first surface 214 may be formed with fine irregularities or may be a curved surface. When the first surface is formed as a curved surface, a lenticular lens pattern may be formed. 1 shows a pattern in which one plane is formed on the top (first surface) and the slope is plane, and the cross-section is in a trapezoidal shape (for example, a cut-prism shape in which the top of a prism having a triangular cross section is cut) . However, when the positive optical pattern of the embossed pattern is a convex pattern in which the first surface is formed at the top and the inclined surface is a curved surface (e.g., a cut-lenticular lens in which the top of the lenticular lens pattern is cut, A cut-micro lens in a cut form) may be included in the scope of the present invention. It may also include a pattern in which the cross section is an N-square (N is an integer of 3 to 20) such as a rectangle or a square.

The first surface 214 may be formed parallel to at least one of the planar portion 212, the lowest surface of the pattern layer 210, 1 shows a case in which the lowest surfaces of the first surface 214, the flat portion 212, and the pattern layer 210 of the optical pattern 211 are parallel to each other.

The first side 214 may have a width A of about 0.5 占 퐉 to about 30 占 퐉, specifically about 1 占 퐉 to about 15 占 퐉. In the above range, it can be used in an optical display device, and an effect of improving the contrast ratio can be expected.

The optical pattern 211 may have an aspect ratio H1 / W of about 0.1 to about 10, specifically about 0.1 to about 7.0, and more specifically about 0.1 to about 5.0. In the above range, it is possible to improve the contrast ratio and the viewing angle at the side in the optical display device.

The maximum height H1 of the optical pattern 211 may be greater than about 0 占 퐉 and less than about 20 占 퐉, specifically greater than about 0 占 퐉 and less than about 15 占 퐉, and more specifically, greater than about 0 占 퐉 and less than or equal to about 10 占 퐉. In the above range, the improvement of the contrast ratio, the improvement of the viewing angle, and the improvement of the luminance are shown, and the moire and the like may not appear.

The maximum width W of the optical pattern 211 may be greater than about 0 占 퐉 and less than about 20 占 퐉, specifically greater than about 0 占 퐉 and less than about 15 占 퐉, and more specifically, greater than about 0 占 퐉 and less than or equal to about 10 占 퐉. In the above range, the improvement of the contrast ratio, the improvement of the viewing angle, and the improvement of the luminance are shown, and the moire and the like may not appear.

FIG. 1 shows a pattern portion in which neighboring optical patterns have an optical pattern in which the base angle, the width of the first surface, the maximum height, and the maximum width are the same. However, neighboring optical patterns may have different base angles, widths of first side, maximum height, and maximum width, respectively.

The flat portion 212 can increase the front luminance by emitting light that has passed through the pattern layer 210 to the gap fill layer 220.

The ratio (W / L) of the maximum width W of the optical pattern 211 to the width L of the flat portion 212 is greater than about 0 and about 9 or less, specifically about 0.1 to about 3, About 0.15 to about 2. In the above range, the difference between the front contrast ratio and the side contrast ratio can be reduced, and the contrast ratio can be increased in the same side viewing angle and the same front viewing angle. The width L of the flat portion 212 may be about 1 탆 to about 50 탆, specifically about 1 탆 to about 20 탆. In the above range, the front luminance may be increased.

The maximum width W of one optical pattern 211 and the immediately adjacent flat portion 212 form one period P. The period P may be from about 1 [mu] m to about 50 [mu] m, specifically from about 1 [mu] m to about 40 [ Moire can be prevented while the contrast ratio is improved within the above range.

FIG. 1 shows pattern portions having the same period and maximum width, but the period and the maximum width may be different from each other.

Although not shown in Fig. 1, Fig. 1 shows that the optical pattern is formed in an elongated form of a stripe shape in the longitudinal direction of the optical pattern, but the optical pattern may be formed in a dot shape. The " dot " means that the combination of the fill pattern and the optical pattern is dispersed. Preferably, the optical pattern is elongated in a stripe shape to produce a right-and-left viewing angle enlarging effect.

The difference in refractive index between the pattern layer 210 and the gap fill layer 220 is about 0.06 or more, preferably about 0.08 to about 0.3, more preferably about 0.08 to about 0.2, and more preferably about 0.08 to about 0.15. The light diffusing effect compared to the front CR reduction can be excellent. For example, be about 0.06, 0.07, 0.08, 0.09, 0.1, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19, 0.2, 0.25 or 0.3.

The pattern layer 210 may have a refractive index of at least about 1.52, preferably from about 1.55 to about 1.70, more preferably from about 1.60 to about 1.70. As described above, the higher the refractive index, the higher the difference in refractive index between the gap fill layer and the light diffusion effect can be maximized.

The pattern layer 210 may be formed of a composition for a pattern layer including at least one of a thermosetting resin and a photocurable resin capable of providing the refractive index.

For example, the pattern layer 210 may be formed of at least one of a resin having an aromatic group and a resin having no aromatic group (non-aromatic group resin). The resin having an aromatic group may include, for example, a resin having fluorene or naphthalene, but is not limited thereto.

The pattern layer 210 may be formed of a composition for a pattern layer comprising at least one of a thermosetting monomer capable of providing the refractive index, a photocurable monomer, and the like. For example, the composition for a pattern layer may contain two or more functional (meth) acrylic monomers.

Specifically, the (meth) acrylic monomer is at least one selected from the group consisting of ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, butanediol di (meth) acrylate, hexanediol di (meth) acrylate, tricyclodecane dimethanol Acrylate, diethylene glycol di (meth) acrylate, nonane diol di (meth) acrylate, ethoxylated hexanediol di (meth) acrylate, propoxylated hexanediol di (Meth) acrylate, neopentyl glycol di (meth) acrylate, ethoxylated neopentyl glycol di (meth) acrylate, dipropylene glycol di (Meth) acrylate such as tripropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, and hydroxypivalic acid neopentyl glycol di Meth) acrylics;

Acrylate, trimethylolpropane tri (meth) acrylate, ethoxylated trimethylolpropane tri (meth) acrylate, propoxylated trimethylolpropane tri (meth) acrylate, tris 2-hydroxyethylisocyanurate tri (Meth) acrylate such as tri (meth) acrylate, pentaerythritol tri (meth) acrylate, dipentaerythritol tri (meth) acrylate and ditrimethylol propane tri (meth) (Meth) acrylic type; (Meth) acrylate such as pentaerythritol tetra (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate and dipentaerythritol tetra (meth) acrylate; (Meth) acrylate such as dipentaerythritol penta (meth) acrylate and ditrimethylol propane penta (meth) acrylate; (Meth) acrylate such as dipentaerythritol hexa (meth) acrylate, ditrimethylol propane hexa (meth) acrylate, and the like.

The pattern layer may be formed of a composition for a pattern layer comprising at least one of a thermosetting resin, a photocurable resin and at least one of a thermosetting monomer and a photocurable monomer capable of providing the refractive index. At least one of a thermosetting resin, a photocurable resin, and at least one of a thermosetting monomer and a photocurable monomer may form a matrix of a pattern layer.

The pattern layer may be formed of a composition for a pattern layer containing at least one of high refractive index inorganic particles such as zirconium oxide (zirconia) and titanium oxide (titania). The composition for a pattern layer containing inorganic particles having a high refractive index can increase the refractive index of the pattern layer and enhance the light reliability of the pattern layer even when the composition does not include a resin having an aromatic group. A resin having an aromatic group may be yellowed upon prolonged exposure to external light ultraviolet rays, which may lower light reliability. The inorganic particles of high refractive index may be present in the pattern layer in an amount of from about 10% to about 80%, preferably from about 20% to about 80%, more preferably from about 20% to about 75% By weight to about 70% by weight. Within the above range, the refractive index of the pattern layer can be increased, and the light reliability can be improved.

The inorganic particles having a high refractive index may have a refractive index of about 1.8 or more, and preferably about 2.0 or more, for example, about 2.0 to about 3.0, with a refractive index higher than that of the matrix of the pattern layer. Within the above range, the refractive index of the pattern layer can be easily secured. The inorganic particles may include non-surface-treated particles, but they can be surface-treated to improve compatibility with other components. The surface treatment can be from about 5% to about 50% of the total surface area of the inorganic particles. Preferably, the pattern layer may include zirconia, and the refractive index of the gap layer may be easily controlled so that the visibility improving effect can be improved.

The average particle diameter (D50) of the inorganic particles having a high refractive index may be about 1 nm to about 80 nm, preferably about 5 nm to about 50 nm. The average particle diameter (D50) can be measured by a conventional method known to a person skilled in the art. In the above range, scattering of light does not occur and the effect of increasing the refractive index of the high refractive index layer may be obtained.

The composition for a pattern layer may further include at least one of a photoinitiator and a thermal initiator which cures the composition to facilitate pattern layer formation. For example, at least one of phosphorus, triazine, acetophenone, benzophenone, thioxanthone, benzoin, oxime, and phenylketone.

The composition for a pattern layer may further contain conventional additives such as a release agent, a defoaming agent, a leveling agent, an antioxidant, an ultraviolet absorber, and a light stabilizer. The composition for the pattern layer may be a solventless type that does not contain a solvent, but it may further include a solvent to facilitate pattern layer formation. As the solvent, a usual solvent may be used.

Gap fill layer

The gap fill layer 220 is directly formed on one surface of the pattern layer 210 and is formed on the light output surface of the pattern layer 210. The gap fill layer 220 can increase the light diffusion effect by diffusing the light incident from the light exit surface of the pattern layer 210.

The gap fill layer 220 may be a planarization layer that fills at least a portion of the gap between the optical pattern 211 of the pattern layer 210 and the neighboring optical pattern 211 to planarize the contrast ratio improving layer 200.

In one embodiment, the gap fill layer 220 can completely fill the gap between the optical pattern 211 of the pattern layer 210 and the neighboring optical pattern 211.

The thickness of the gap fill layer 220 is greater than the maximum height of the optical pattern 211 to completely fill the gap between the optical pattern 211 of the pattern layer 210 and the neighboring optical pattern 211 The top portion of the optical pattern 211 can be completely covered.

The refractive index of the pattern layer 210 is higher than that of the gap fill layer 220. The contrast ratio improving layer 200 composed of the pattern layer 210 and the gap fill layer 220 can improve the side contrast ratio by diffusing and emitting the light incident from the light incident surface of the pattern layer 210, The reduction of the front contrast ratio can be minimized and the difference between the front contrast ratio and the side contrast ratio can be reduced and the contrast ratio can be increased in the same side view angle and the same front view angle.

The gap fill layer 220 may have a refractive index of greater than about 0 to about 1.53, specifically from about 1.43 to about 1.525. In the above range, the refractive index difference with respect to the pattern layer is increased, so that the visibility effect can be excellent.

The gap fill layer 220 may comprise a matrix and first particles 230 included in the matrix. At least a part of the first particles 230 may be exposed on the surface of the gap fill layer 220 to form surface irregularities and have the same refractive index as the matrix. By this, the light passing through the pattern layer 210 is not scattered by the first particles, so that the first particles exposed on the surface do not affect the visibility improving effect, and the antiglare effect by surface irregularities, Can also be provided. Not only some of the first particles 230 may be exposed to the surface of the gap fill layer 220, but the rest of the first particles may be dispersed among the optical patterns.

Even if the first particles are dispersed between the optical patterns, the first particles have a minimum internal haze in the range of about 0 to about 0.03 in absolute value of the refractive index difference with respect to the matrix, so that the visibility improving effect is not affected. For example, the absolute value of the refractive index difference may be about 0, 0.005, 0.01, 0.015, 0.02, 0.025 or 0.03.

The first particles 230 may comprise from about 1% to about 50%, preferably from about 2% to about 40%, and more preferably from about 2% to about 30%, by weight of the gap fill layer 220, &Lt; / RTI &gt; In the above range, external irregularities may be formed to have an external light scattering effect.

In one embodiment, less than about 1% and less than about 20% of the first particle diameter included in the gap fill layer may be exposed to the top surface of the gap fill layer surface, i.e., the gap fill layer, So that unevenness may occur. Within this range, an antiglare effect can be obtained while maintaining the effect of improving the contrast ratio of light emitted from the pattern layer.

In one embodiment, the maximum distance (also referred to as a "thickness") between the top surface 214 of the pattern layer 210 and the top surface of the gap fill layer 220 is greater than about 0 μm and not greater than about 15 μm, Preferably from about 5 占 퐉 to about 10 占 퐉. In the above range, the effect of improving the visibility of the light coming from the top of the pattern layer is not affected, and the antiglare effect can be sufficiently obtained. When the conventional antiglare film is laminated on the optical film for improving the contrast ratio, the light emitted from the pattern layer can not reach the antiglare particles via the film constituting the antiglare film. In the present invention, by setting the absolute value of the refractive index difference of the matrix and the first particle in the gap fill layer to about 0 to about 0.03, the side visibility can be improved and the antiglare effect can be obtained by the external irregularity.

The first particles 230 may include particles that scatter the light incident from the matrix to provide an anti-glare effect. The first particle may comprise spherical or amorphous particles, and may preferably comprise spherical particles. As a result, the appearance can be improved by uniformly scattering light on the surface of the gap fill layer.

The first particles may have an average particle diameter (D50) of greater than about 0 microns but not greater than about 20 microns, preferably from about 2 microns to about 15 microns, more preferably from about 2 microns to about 10 microns. In the above range, it can be included in the gap fill layer, and an antiglare effect can be obtained.

The average particle diameter of the first particles may be smaller than the width of the first surface which is the top of the positive optical pattern or the maximum width of the optical pattern of the positive or the maximum width of the flat portion. In such a case, an antiglare effect may be produced and moire may not occur.

The first particles 230 are particles having an absolute refractive index difference of about 0 to about 0.03 with respect to the matrix, and the lower visibility effect can be maintained. An antiglare effect can be obtained with respect to the light incident from the pattern layer. In one embodiment, the first particles may have the same or lower refractive index than the matrix.

The first particle may include at least one of organic particles, inorganic particles, and organic-inorganic hybrid particles as conventional antiglare particles. The organic particles may be formed of polymethylmethacrylate, polystyrene, or copolymers of polymethylmethacrylate and styrene, but are not limited thereto. The inorganic particles may include, but are not limited to, silica, titania, zirconia, alumina, and the like. Preferably, the compatibility with the matrix can be improved by using organic particles, more preferably polymethylmethacrylate particles.

The first particle may have a refractive index of greater than about 0 to about 1.53, specifically from about 1.43 to about 1.53, and more specifically from about 1.43 to about 1.525.

The matrix can support the gap fill layer and support the first particle exposed on the surface of the gap fill layer. The matrix may be formed of a composition for a gap fill layer capable of securing an absolute value of the refractive index difference of about 0 to about 0.03 with respect to the first particles. The matrix may have a refractive index of greater than about 0 to about 1.53, specifically from about 1.43 to about 1.53, and more specifically from about 1.43 to about 1.525.

The composition for the gap fill layer may comprise a photocurable compound, a (meth) acrylic monomer, an initiator, and a first particle.

The photocurable compound may include a compound having a UV curable group such as a (meth) acrylate group or an epoxy group (at least one of oligomers and resins). The photocurable compound may include at least one of a bifunctional or higher functional (meth) acrylic oligomer and a resin formed therefrom. The photocurable compound is a polyfunctional urethane (meth) acrylate synthesized from a polyfunctional (meth) acrylate such as a polyhydric alcohol and an ester of (meth) acrylic acid, or a polyhydric alcohol, an isocyanate compound, or a hydroxy ester of (meth) Acrylate. &Lt; / RTI &gt; The (meth) acrylic monomer may include at least one of the above-mentioned (meth) acrylic monomers in the composition for a pattern layer. The initiator may include one or more of the initiators described above in the composition for a pattern layer. The first particle is as described above.

The composition for the gap fill layer may further contain conventional additives such as a dispersant, a defoaming agent, a leveling agent, a slip agent, an antioxidant, an ultraviolet absorber, a light stabilizer, and a filler.

For example, a UV-reactive silicone additive such as UV3500 may be used as a leveling agent. For example, a deagglomeration type dispersant (e.g., Disperbyk-2163) of a block copolymer having a high molecular weight may be used as a dispersant. For example, a UV curable fluorine-based acrylic compound (e.g., KY 1200 1203) or the like may be used.

The composition for the gap fill layer may be a solventless type that does not contain a solvent, but it may further include a solvent to facilitate formation of a gap fill layer. The solvent may be any conventional solvent, and may include, but is not limited to, at least one of propylene glycol monomethyl ether acetate and methyl isobutyl ketone.

The composition for the gap fill layer may further include second particles having a higher refractive index than the first particles 230. This makes it possible to ensure that the absolute value of the difference in refractive index between the matrix and the first particle during curing of the composition for the gap fill layer exceeds about 0 to about 0.03.

The second particle may have a refractive index of at least about 1.8, preferably at least about 2.0, more preferably from about 2.0 to about 3.0. Within this range, the refractive index of the gap fill layer can be easily secured.

The second particle may include particles substantially the same as the high refractive index inorganic particles described above in the pattern layer. Preferably, the second particle may comprise zirconia. The average particle size (D50) of the second particles may be from about 5 nm to about 80 nm. The average particle diameter (D50) can be measured by a conventional method known to a person skilled in the art. Within this range, there may be an effect of increasing the refractive index of the high-refraction layer.

The second particles may comprise from about 10 wt% to about 80 wt%, preferably from about 10 wt% to about 75 wt%, and from about 15 wt% to about 70 wt% of the composition or gap fill layer for the gap fill layer. Within this range, there may be an effect of maintaining the hardness of the layer while maintaining the dispersibility.

The maximum thickness of the gap fill layer 220 may be greater than about 0 micrometers but not greater than about 30 micrometers, e.g., greater than about 0 micrometers but less than about 20 micrometers. In this range, it is possible to prevent the occurrence of warpage such as curl.

The first particles 230 of the contrast enhancement layer 200 may be included in an amount of about 1 wt% to about 50 wt%, preferably about 2 wt% to about 40 wt%. In the above range, the antiglare effect can be obtained while maintaining the effect of improving the contrast ratio.

The haze of the contrast improving optical film 10 may be about 0% or more and about 35% or less. And can be used in an optical display device in the above range.

Hereinafter, a polarizing plate according to an embodiment of the present invention will be described with reference to FIG. 2 is a cross-sectional view of a polarizer according to an embodiment of the present invention.

Referring to FIG. 2, the polarizing plate 20 includes a polarizing film 300 and a contrast ratio improving optical film. The contrast ratio improving optical film may include a contrast ratio improving optical film according to an embodiment of the present invention.

The contrast ratio improving optical film may be formed on the light exit surface of the polarizing film 300. The contrast ratio improving optical film diffuses the polarized light transmitted through the polarizing film 300 to improve the front contrast ratio, the side contrast ratio, and improve the viewing angle.

The polarizing film 300 can transmit the light incident from the liquid crystal panel to the contrast enhancing layer 200 by polarizing the light. The polarizing film 300 is formed on the light incident surface of the contrast enhancing layer 200.

The polarizing film 300 may include a polarizer. Specifically, the polarizer may include a polyvinyl alcohol polarizer produced by uniaxially stretching a polyvinyl alcohol film, or a polyene polarizer produced by dehydrating a polyvinyl alcohol film. The polarizer may have a thickness of 5 占 퐉 to 40 占 퐉. In the above range, it can be used in an optical display device.

The polarizing film 300 may include a polarizer and a protective layer formed on one surface of the polarizer, that is, a light incident surface of the polarizer. The protective layer can protect the polarizer, thereby increasing the reliability of the polarizer and increasing the mechanical strength of the polarizer. The protective layer may comprise one or more of an optically transparent, protective film or protective coating layer. The protective layer is as described above.

The polarizing plate can be formed by a conventional method. For example, the optical film may be manufactured by preparing an optical film having improved contrast ratio by the above-described method, and bonding the polarizing film to the first optical film through the first resin layer. The first resin layer has excellent adhesion to the polarizing film.

The liquid crystal display device of the present invention may include the polarizing plate of the present invention. In one embodiment, the liquid crystal panel can be included as a viewing side polarizing plate. The " viewer-side polarizing plate " is disposed opposite to the screen side, i.e., the light source side, with respect to the liquid crystal panel.

In one embodiment, the liquid crystal display device may include a backlight unit, a first polarizing plate, a liquid crystal panel, and a second polarizing plate sequentially laminated, and the second polarizing plate may include the polarizing plate of the present invention. The liquid crystal panel may employ a VA (vertical alignment) mode, an IPS mode, a PVA (patterned vertical alignment) mode, or an S-PVA (super-patterned vertical alignment) mode. In another embodiment, it may be included as a light source side polarizing plate for a liquid crystal panel. The " light source side polarizing plate " is disposed on the light source side with respect to the liquid crystal panel. In another embodiment, both the viewing-side polarizing plate and the light-source-side polarizing plate with respect to the liquid crystal panel may include the polarizing plate of the present invention.

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

Manufacturing example  One: For pattern layer  Composition manufacturing

73 parts by weight of zirconia-containing solvent-free solution HR-10-1 (average particle diameter (D50) of zirconia in Japanese catalyst, 11 nm in refractive index, dispersion of zirconia in benzyl acrylate as 80% by weight in high refractive index compound, refractive index 1.67), trimethylpropane , And 4.5 parts by weight of initiator TPO LG (IGC) and 0.5 parts by weight of release agent BYK 3500 were mixed to prepare a composition for a pattern layer. The refractive index of the composition for a pattern layer was 1.60. The composition for a pattern layer contains zirconia in an amount of 51% by weight based on the solid content.

Manufacturing example  2: Preparation of composition for gap fill layer

23 parts by weight of UP111 (solid content: 70% by weight, solvent: PEME (propylene glycol methyl ether)) as a photo-curable compound, 8.4 parts by weight of SR833S (Sartomer Co.), 8 parts by weight of HDDA (ENTIS) 46 parts by weight of monomethyl ether acetate) and 12 parts by weight of MIBK (methyl isobutyl ketone) were mixed and stirred. After the stirring was completed, 1.15 parts by weight of initiator Omnirad 184 (IGC), 0.03 part by weight of UV-reactive silicone additive UV3500, 0.07 part by weight of dispersant Disperbyk-2163 (BYK), and 0.05 part by weight of kneader KY1203 (Shin Etsu) The crude solution was prepared.

A composition for a gap fill layer was prepared by mixing MSX-105 (refractive index: 1.495, polymethylmethacrylate particles, average particle diameter (D50): 5.41 占 퐉, monodispersed particles, Sekisui Chemical Co., Ltd.) as organic particles. The composition for the gap fill layer contains 6% by weight of solid-based organic particles.

Manufacturing example  3: Preparation of composition for gap fill layer

The crude liquid was prepared in the same manner as in Production Example 2.

MBX-2H (refractive index: 1.495, polymethylmethacrylate particles, average particle diameter (D50): 2.7 占 퐉, neutral dispersed particles, Sekisui Chemical Co., Ltd.) was mixed with the organic solvent to prepare a gap fill layer composition. The composition for the gap fill layer contains 6% by weight of solid-based organic particles.

Manufacturing example  4: Preparation of composition for gap fill layer

24 parts by weight of UP111 (solid content: 70% by weight, solvent: PEME) as a photo-curable compound, 17 parts by weight of zirconia-containing solvent solution HR-10-1 (Japanese Catalyst, average particle diameter of zirconia (D50) 46 parts by weight of PGME and 12 parts by weight of MIBK were mixed and stirred. After the stirring was completed, 1.15 parts by weight of initiator Omnirad 184 (IGC), 0.03 part by weight of UV-reactive silicone additive UV3500, 0.07 part by weight of dispersant Disperbyk-2163 (BYK), and 0.05 part by weight of kneader KY1203 (Shin Etsu) The crude solution was prepared.

A composition for a gap fill layer was prepared by mixing MSX-105 (refractive index: 1.495, polymethylmethacrylate particles, average particle diameter (D50): 5.41 占 퐉, monodispersed particles, Sekisui Chemical Co., Ltd.) as organic particles. The composition for the gap fill layer contains 6% by weight of solid-based organic particles.

Manufacturing example  5: Preparation of composition for gap fill layer

The crude liquid was prepared in the same manner as in Production Example 2.

A composition for a gap fill layer was prepared by mixing SMX-5R (refractive index: 1.555, polystyrene-polymethylmethacrylate copolymer particles, average particle size (D50): 5 占 퐉, polydisperse particles, . The composition for the gap fill layer contains 6% by weight of solid-based organic particles.

Manufacturing example  6: Gap Peel layer  Composition manufacturing

The crude liquid was prepared in the same manner as in Production Example 2.

SBX-4 (refractive index: 1.595, polystyrene particles, average particle diameter (D50): 4 占 퐉, polydisperse particles, Sekisui Co., Ltd.) was mixed with the organic solvent to prepare a gap fill layer composition. The composition for the gap fill layer contains 6% by weight of solid-based organic particles.

Manufacturing example  7: Gap Peel layer  Composition manufacturing

The crude liquid was prepared in the same manner as in Production Example 2. The particles were not included.

Manufacturing example  8: Gap Peel layer  Composition manufacturing

38.5 parts by weight of UP111 (solid content: 70% by weight, solvent: PEME) as a photo-curable compound, 38.5 parts by weight of zirconia-containing solvent solution HR-10-1 (Japan Catalyst, average particle diameter of zirconia (D50) 6.5 parts by weight of zirconia dispersed in benzyl acrylate at 80% by weight), 42 parts by weight of PGME and 12 parts by weight of MIBK were mixed and stirred. After the stirring was completed, 1.15 parts by weight of initiator Omnirad 184 (IGC), 0.03 part by weight of UV-reactive silicone additive UV3500, 0.07 part by weight of dispersant Disperbyk-2163 (BYK), and 0.05 part by weight of kneader KY1203 (Shin Etsu) The crude solution was prepared.

MXS-105 (refractive index: 1.495, polymethylmethacrylate particles, average particle diameter (D50): 5.41 mu m, monodispersed particles, Sekisui Co., Ltd.) was mixed with the above crude liquid to prepare a gap fill layer composition. The composition for the gap fill layer contains 6% by weight of solid particles based on solids, and 16% by weight of zirconia.

Manufacturing example  9: For pattern layer  Composition manufacturing

40 parts by weight of a zirconia-containing solvent-free solution HR-10-1 (average particle diameter (D50) of zirconia of Japanese catalyst, 11 nm of high refractive index compound, dispersed in benzyl acrylate at 80% by weight of zirconia, refractive index of 1.67) , And 4.5 parts by weight of initiator TPO LG (IGC) and 0.5 part by weight of release agent BYK 3500 were mixed to prepare a composition for a pattern layer. The refractive index of the composition for a pattern layer was 1.55. In the composition for a pattern layer, zirconia is contained in an amount of 28% by weight based on the solid content.

Example  One

A coating layer was prepared by coating the composition for a pattern layer of Production Example 1 on one side of a polyethylene terephthalate film (SKC, thickness: 40 탆) as a protective layer. A pattern and a flat part were applied to the coating layer using an optical film on which a prism pattern and a flat part were formed with a positive angle and cured to form a pattern layer.

The composition for gap fill layer of Production Example 2 was coated with # 18 on the prepared pattern layer, dried at 80 ° C for 2 minutes, and photocured to prepare an optical film having improved contrast ratio. Specific specifications of the optical pattern and the flat part in the optical film having the improved contrast ratio are shown in Table 1 below.

The polyvinyl alcohol film was stretched three times at 60 ° C, adsorbed iodine, and then stretched 2.5 times in an aqueous boric acid solution at 40 ° C to prepare a polarizer. A polarizing plate was prepared by adhering a polarizer to the other side of the protective layer among the contrast improving optical films with an adhesive.

Example  2

A contrast ratio improving optical film and a polarizing plate were produced in the same manner as in Example 1, except that the composition for a gap-fill layer in Production Example 3 was used in place of the composition for a gap-fill layer in Production Example 2. [

Example  3

A contrast ratio improving optical film and a polarizing plate were prepared in the same manner as in Example 1, except that the composition for a gap-fill layer in Production Example 8 was used in place of the composition for a gap-fill layer in Production Example 2.

Comparative Example  1 to Comparative Example  4

In Example 1, a contrast ratio improving optical film and a polarizing plate were prepared in the same manner as in Production Example 2, except that the composition for a gap-fill layer in Table 2 was used in place of the composition for a gap-fill layer.

Comparative Example  5

A contrast ratio improving optical film and a polarizing plate were produced in the same manner as in Example 3, except that the pattern layer composition of Production Example 9 was used instead of the pattern layer composition of Production Example 1

Reference Example  One

A polarizer was prepared in the same manner as in Example 1. A polarizing plate was prepared by adhering a polyethylene terephthalate film (SKC, thickness: 40 mu m) as a protective layer to one surface of a polarizer with an adhesive.

The following properties of the optical film and the polarizing plate were evaluated, and the results are shown in Table 2 below.

The haze and transmittance ( unit:% ) of haze and transmittance of the optical film were measured by NDH 2000 manufactured by Nippon Denshok. NDH2000 is DF (diffuse transmitted light) in the wavelength range of 400nm to 700nm. Measure PT (parallel transmitted light), TT (total transmitted light), and haze.

DF: The sum of the light that is diffused through the sample in the lamp and transmitted

PT: Sum of the light transmitted through the sample straight through the light in the lamp

TT: Sum of diffuse transmission light and parallel transmission light

Haze: The degree of cloudiness that appears through the sample

Haze (%) = DF (diffused light) / TT (total transmitted light) x100

Side Contrast Ratio ( Unit:% ) and Viewing Angle ( Unit: ° ) : The side contrast ratio and 1/2 viewing angle (upper and lower, left and right) were evaluated for the polarizing plates of Examples and Comparative Examples, and the results are shown in Table 2 below. Side contrast ratio, and 1/2 viewing angle were manufactured and evaluated for the liquid crystal display device module in the following manner.

Preparation of first polarizing plate

The polyvinyl alcohol film was stretched three times at 60 DEG C, adsorbed to iodine, and then stretched 2.5 times in an aqueous boric acid solution at 40 DEG C to prepare a first polarizer. A triacetyl cellulose film (thickness: 80 占 퐉) was bonded to both surfaces of the first polarizer with a polarizer adhesive (Z-200, manufactured by Nippon Goshei) to prepare a first polarizer plate.

Manufacture of Module for Liquid Crystal Display

The first polarizing plate, the liquid crystal panel (PVA mode), and the polarizing plates prepared in the above-mentioned Examples and Comparative Examples were sequentially assembled to prepare a module for a liquid crystal display device. The polarizing plates prepared in Examples and Comparative Examples were assembled with a viewer-side polarizing plate, and the gap fill layer was arranged at the outermost side on the viewing side.

A liquid crystal display device including a LED light source, a light guide plate, and a module for a liquid crystal display device and including a one-sided edge type LED light source (same configuration as the Samsung LED TV (UN32H5500) except for the configuration of the module for the liquid crystal display device of the embodiment and the comparative example ).

The luminance values were measured in the white mode and the black mode with respect to the sides of the spherical coordinate system (0 °, 60 °) using an EZCONTRAST X88RC (EZXL-176R-F422A4, ELDIM). The side contrast ratio was calculated as the ratio of the luminance value of the white mode to the luminance value of the black mode in the spherical coordinate system (0 °, 60 °). The 1/2 viewing angle was set to an angle at which half of the front luminance was displayed in the white mode.

External light scattering effect : The external light scattering was evaluated by measuring the 60 degree reflection gloss using BYK Gardner according to JIS Z8741 and ISO 2813. [ When the 60 ° reflection gloss was less than 90, the external light scattering effect was evaluated as " Yes "

* Difference in refractive index 1: Absolute value of the difference between the refractive index of the matrix and the refractive index of the first particle in the gap fill layer

Refractive index difference 2: pattern layer refractive index-refractive index of the gap fill layer

As shown in Table 2, the polarizing plate of the present invention has an excellent effect of improving the front viewability and the side viewability, the side contrast ratio is excellent, and the external light scattering effect due to the particles can also be obtained.

On the other hand, in Comparative Example 1 in which the absolute value of the refractive index difference between the matrix and the first particle deviates from the range of the present invention and the refractive index difference between the pattern layer and the gap fill layer is less than 0.06, Of Comparative Example 2 and Comparative Example 3 had an effect of scattering external light, but the effect of improving the frontal viewability and side viewability was weak and the side contrast ratio was not good.

In Comparative Example 4, which does not contain particles, there is no external light scattering effect, and therefore, in order to obtain an external light scattering effect, it is necessary to further laminate the film, and the effect of the present invention can not be obtained.

In Comparative Example 5 in which the absolute value of the refractive index difference between the matrix and the first particle satisfies the range of the present invention but the refractive index difference between the pattern layer and the gap fill layer is outside the scope of the present invention, the side contrast ratio is poor, I did.

It will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims.

Claims (14)

1. A protective layer and a pattern layer formed on the protective layer,

   Wherein the pattern layer has a pattern portion having a flat portion between an optical pattern on the one side and a positive optical pattern of the positive angle adjacent to the optical pattern on the one side and the optical pattern has a base angle & 90 DEG, the pattern portion satisfies the following formula (1)

   <Formula 1>

   About 1 < P / W &lt; / = about 10

   (In the above formula (1), P is the period (unit: mu m) of the pattern portion,

   W is the maximum width (unit: 占 퐉) of the optical pattern)

   Further comprising a gap fill layer directly contacting one surface of the pattern layer,

   Wherein the gap fill layer comprises a matrix and first particles contained in the matrix,

   The absolute value of the refractive index difference of the matrix and the first particle is from about 0 to about 0.03,

   Wherein a difference in refractive index between the pattern layer and the gap fill layer is about 0.06 or more.
2. The optical film of claim 1, wherein the gap fill layer comprises irregularities of at least about 1% and less than about 20% of the first particle diameter.
3. The optical film of claim 1, wherein a maximum distance between a top surface of the pattern layer and a top surface of the gap fill layer is greater than about 0 탆 and not greater than about 15 탆.
4. The optical film of claim 1, wherein an average particle diameter of the first particles is smaller than a width of a first surface which is a top portion of the optical pattern of the emboss.
5. The optical film of claim 1, wherein the first particles are comprised between about 1% and about 50% by weight of the gap fill layer.
6. The optical film according to claim 1, wherein the first particles include antiglare particles.
7. The optical film of claim 1, wherein the ratio (W / L) of the maximum width (W) of the optical pattern of the positive angle to the width (L) of the flat portion is about 0.1 to about 3.
8. The optical film according to claim 1, wherein the first particles are formed of at least one of polymethylmethacrylate, polystyrene, and a copolymer of polymethylmethacrylate and styrene.
9. The optical film according to claim 1, wherein the pattern layer is formed of a composition for a pattern layer containing a resin having no aromatic group and inorganic particles having high refractive index.
10. The optical film according to claim 1, wherein the relief optical pattern includes an optical pattern whose cross section is trapezoidal, rectangular or square.
11. The optical film of claim 1, wherein the refractive index of the pattern layer is higher than the refractive index of the gap fill layer.
12. The optical film of claim 1, wherein the gap fill layer further comprises second particles having a refractive index higher than that of the first particles.
13. Polarizing film; And a contrast ratio improving optical film formed on a light output surface of the polarizing film, wherein the contrast improving optical film includes the contrast ratio improving optical film according to any one of claims 1 to 12.
14. 14. A liquid crystal display device comprising the polarizing plate of claim 13.

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