TW201918764A - Optical film, polarizing plate, and liquid crystal display apparatus - Google Patents

Abstract

Provided is an optical film, the optical film including: a protective layer; and a contrast ratio improvement layer including a second resin layer and a first resin layer, wherein the second resin layer has a refractive index greater than that of the first resin layer, and the first resin layer has a patterned portion which has at least two embossed optical patterns and flat portions between the embossed optical patterns and immediately adjacent embossed optical patterns in at least a portion thereof facing the second resin layer, wherein a base angle ([theta]) of the embossed optical pattern is in a range of about 75 DEG to about 90 DEG, and the patterned portion satisfies Expression 1 as described in the specification, and wherein at least one of the first resin layer and the second resin layer includes at least one of a metal complex dye and an organic black dye. In addition, provided are a polarizing plate including the optical film and a liquid crystal display apparatus including the polarizing plate.

Description

Optical film, polarizing plate, and liquid crystal display device

The present invention relates to an optical film, a polarizing plate including the optical film, and a liquid crystal display device including the polarizing plate.

The liquid crystal display device operates in such a manner that light from the backlight unit is emitted through the liquid crystal panel. Light from the backlight unit is incident perpendicular to the screen of the liquid crystal display device. Therefore, the contrast ratio (CR) on the side surface of the liquid crystal display device is lower than the contrast on the front surface thereof. Therefore, research and development of an optical film (increasing side contrast) was carried out.

The optical film includes a high refractive index layer and a low refractive index layer to improve side contrast caused by the optical pattern. The contrast on the side surface can be improved by an optical pattern in which the flat portion is alternately formed with the optical pattern. However, although the contrast on the side surface is improved to some extent by the optical film, the light emitted to the front surface is disturbed by the optical pattern, and thus the front contrast is lowered. Even when external light is still incident on the optical pattern when the optical display device is not driven, the reflectance is increased.

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

The present invention is directed to providing an optical film capable of improving contrast on a front surface and reducing reflectance.

The present invention is directed to providing an optical film capable of reducing the degree of color shift on a side surface.

The present invention is directed to providing an optical film having a good appearance by allowing the composition for the high refractive index layer to be sufficiently cured to minimize the separation of the dye from the high refractive index layer.

The present invention is directed to providing an optical film having a good appearance by allowing the composition for the low refractive index layer to be sufficiently cured to minimize the separation of the dye from the low refractive index layer.

The present invention is directed to providing an optical film capable of reducing light leakage to a side surface by reducing light emitted to a side surface in a black mode, and improving contrast in a black mode.

The present invention is directed to providing an optical film comprising a second resin layer having improved brightness and having high light transmittance (although containing a dye).

The present invention is directed to providing a polarizing plate and an optical display device comprising the optical film of the present invention.

The optical film of the present invention comprises a protective layer and a contrast improving layer, the contrast improving layer comprising a second resin layer and a first resin layer facing the second resin layer, the second resin layer and the first resin layer being from the lower surface of the protective layer Stacking sequentially, wherein the refractive index of the second resin layer is greater than the refractive index of the first resin layer, and the first resin layer has a patterned portion in at least a portion thereof facing the second resin layer, the patterned portion having at least two a raised optical pattern and a flat portion between the raised optical pattern and the immediately adjacent raised optical pattern, wherein the bottom angle (θ) of the raised optical pattern is in the range of from about 75° to about 90°, and patterned Partially satisfies the following Expression 1: <Expression 1> 1 < P/W ≤ 10, where, in Equation 1, P is the pitch (unit: micrometer) of the patterned portion, and W is the relief The maximum width (unit: micrometer) of the optical pattern, at least one of the first resin layer and the second resin layer containing at least one of a metal complex dye and an organic black dye.

The polarizing plate of the present invention comprises a polarizing film and an optical film of the present invention, and the optical film is formed on the polarizing film.

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

The exemplary embodiments will be described in detail with reference to the drawings in order to provide a thorough understanding of the invention. It should be understood that the present invention may be embodied in various forms and is not limited to the embodiments described below. In the drawings, portions that are not related to the description will be omitted for clarity. Similar components throughout the specification will be referred to by like reference numerals.

As used herein, spatially relative terms such as "upper" and "lower" are defined with reference to the drawings. Therefore, it should be understood that "upper" can be used interchangeably with "lower" and "lower" can be used interchangeably with "upper". It will be understood that when a layer is referred to as "on" another layer, the layer may be formed directly on the other layer or the intervening layer may be present. Therefore, it should be understood that when a layer is referred to as being "directly on" another layer, the intervening layer is not inserted.

As used herein, the terms "horizontal direction" and "vertical direction" mean the lateral direction and the longitudinal direction of a rectangular screen of a liquid crystal display, respectively. As used herein, when referring to the horizontal direction in the spherical coordinate system (Φ, θ), the front surface is represented by (0°, 0°), the left end point is represented by (180°, 90°) and (0°, 90 is used). °) When referring to the right end point, the term "side surface" means an area represented by (0°, 60°) or (0°, 80°).

As used herein, the term "top portion" refers to a portion that is located at the uppermost portion of the embossed optical pattern.

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

As used herein, the term "pitch" means the distance between adjacent optical patterns, such as the sum of the maximum width of one optical pattern and the width of a flat portion of the optical pattern.

As used herein, "in-plane retardation (Re)" is a value at a wavelength of 550 nm and is represented by the following expression A: <Expression A> Re = (nx - ny) × d.

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

As used herein, the term "(meth)acrylinyl" refers to acryloyl and/or methacrylinyl.

The inventors of the present invention have completed the present invention by adding a metal complex dye and an organic black dye to at least one of the first resin layer and the second resin layer in the optical film including the patterned portion. At least one of them can improve the contrast on the front surface, can significantly reduce the reflectance, and can reduce the color shift on the side surface, while the patterned portion does not affect the improvement of the contrast on the side surface.

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

Referring to FIG. 1, in the optical film 10, a contrast improving layer 200 is formed on the lower surface of the protective layer 100.

The protective layer

The protective layer 100 may be formed on one surface of the contrast improving layer 200 to support the contrast improving layer 200. The protective layer 100 may be directly formed on the second resin layer 220 of the contrast improving layer 200 to reduce the thickness of the optical film 10. The expression "directly formed on" means that any intervening layer such as an adhesive layer, a bonding layer or a viscous bonding layer is not interposed between the protective layer 100 and the contrast improving layer 200.

The contrast improving layer 200 is formed on the light incident surface of the protective layer 100. Light passing through the contrast improving layer 200 may be emitted through the protective layer 100.

The protective layer 100 may have a total transmittance of about 90% or more (for example, about 90% to about 100%) in the wavelength range of visible light. Within this range, the protective layer 100 can transmit incident light without affecting incident light.

The protective layer 100 may be a protective film or a protective coating having a light incident surface and a light exit surface opposite to the light incident surface. Preferably, the degree of support to the contrast improving layer 200 can be increased by using a protective film as the protective layer 100.

When the protective layer 100 is a protective film, the protective layer 100 may include a single-layer optically transparent resin film. However, the protective layer 100 may include a plurality of stacked resin films. The protective film can be formed by melting and extruding the resin. If necessary, an additional elongation process can be added. The resin may comprise at least one selected from the group consisting of cellulose ester resins comprising triacetyl cellulose (TAC) and the like; and cyclic polyolefin resins comprising a cyclic polyolefin; COP); polycarbonate resin; polyester resin, including polyethylene terephthalate (PET) and the like; polyether oxime resin; polyfluorene resin; polyamine resin Polyimide resin; acyclic polyolefin resin; polyacrylate resin comprising polymethyl methacrylate resin and the like; polyvinyl alcohol resin; polyvinyl chloride resin; Vinyl chloride resin.

The protective film may be a non-elongated film. However, the protective film may be a retardation film or an isotropic optical film having a certain retardation range by elongating the resin in a specific method. In an exemplary embodiment, the protective film may be an isotropic optical film, and the Re of the isotropic optical film ranges from about 0 nm to about 60 nm, specifically about 40 nm. It is within the range of about 60 nm. Within this range, high image quality can be provided by compensating the viewing angle. As used herein, the term "isotropic optical film" means a film in which nx, ny, and nz are substantially the same (where nz represents a refractive index in a direction orthogonal to nx and ny). As used herein, the expression "substantially the same" encompasses not only the case where nx, ny, and nz are completely identical, but also the case where there is an acceptable margin of error between nx, ny, and nz. In another exemplary embodiment, the protective film may be a retardation film having a Re of about 60 nm or more than 60 nm. For example, the Re of the protective film can range from about 60 nanometers to about 500 nanometers, and specifically, from about 60 nanometers to about 300 nanometers. For example, the Re of the protective film can be about 8,000 nanometers or more, more specifically about 10,000 nanometers or more, more specifically about 10,000 nanometers, and more specifically more than about 10,000 nanometers. It is in the range of about 10,100 nm to about 30,000 nm, and more specifically, in the range of about 10,100 nm to about 15,000 nm. Within this range, it is possible to prevent rainbow spots from being visible and to further improve the diffusion effect of light diffused through the contrast improving layer 200.

The protective coating may be made of an activated energy ray curable resin composition containing an active energy ray curable compound and an initiator. The active energy ray-curable compound may include at least one selected from the group consisting of a cationically polymerizable curable compound, a radical polymerizable curable compound, an urethane resin, and an anthrone-based resin. The cationically polymerizable curable compound may comprise at least one selected from the group consisting of an epoxy-based compound having at least one epoxy group in its molecule, and an oxetane-based compound having at least one oxygen in its molecule Cyclobutane ring. The epoxy-based compound may contain at least one selected from the group consisting of a hydrogenated epoxy-based compound, a chain aliphatic epoxy-based compound, a cyclic aliphatic epoxy-based compound, and an aromatic epoxy-based compound.

The radical polymerizable curable compound can be reacted with a (meth) acrylate monomer having at least one (meth) propylene fluorenyloxy group in its molecule with two or more types of functional group-containing compounds It is obtained and may comprise a (meth) acrylate oligomer having at least two (meth) acryloxy groups in its molecule. Examples of the (meth) acrylate monomer may include a monofunctional (meth) acrylate monomer having a single (meth) acryloxy group in its molecule; a difunctional (meth) acrylate monomer, There are two (meth) acryloxy groups in their molecules; and a polyfunctional (meth) acrylate monomer having three or more (meth) acryloxy groups in its molecule. The (meth) acrylate oligomer may comprise at least one selected from the group consisting of urethane (meth) acrylate oligomers, polyester (meth) acrylate oligomers, and epoxy groups (methyl groups). ) acrylate oligomers and/or analogs. The initiator can cure the activated energy ray curable compound. The initiator can include at least one of a cationic photoinitiator and a photosensitizer. Any of the typical initiators known to those skilled in the art can be used as the cationic photoinitiator and photosensitizer.

The thickness of the protective layer 100 can range from about 5 microns to about 200 microns, and specifically, from about 30 microns to about 120 microns. When the protective layer 100 is provided as a type of protective film, the thickness of the protective film may range from about 30 microns to about 100 microns, preferably from about 50 microns to about 90 microns. When the protective layer 100 is provided as a type of protective coating, the thickness of the protective coating can range from about 5 microns to about 50 microns. Within this range, the protective layer 100 can be used in a polarizing plate.

A surface treatment layer such as an undercoat layer, a hard coat layer, an anti-fingerprint layer, an anti-reflection layer, an anti-glare layer, a low reflection layer, or an ultra-low reflection layer may be additionally formed on at least one surface of the protective layer 100 (ie, the upper surface and the lower surface) On the surface). A hard coat layer, an anti-fingerprint layer, an anti-reflective layer or the like may provide additional functions to the protective layer 100, the polarizing film, and the like. The undercoat layer can enhance the adhesion between the protective layer 100 and the adhesive (for example, a polarizer).

Contrast modified layer

The contrast improving layer 200 includes a first resin layer 210 and a second resin layer 220 facing the first resin layer 210. Preferably, the contrast improving layer 200 includes only the first resin layer 210 and the second resin layer 220 by disposing the first resin layer 210 and the second resin layer 220 in direct contact with each other.

The first resin layer 210 is formed on the light incident surface of the second resin layer 220. Light incident from the lower surface of the first resin layer 210 may be emitted to the second resin layer 220. The first resin layer 210 can diffuse light by refracting and emitting light incident from the lower surface thereof in various directions according to the incident position of the light.

The first resin layer 210 is directly formed on the second resin layer 220. The patterned portion to be described below is formed on the interface of the first resin layer 210, and the second resin layer 220 (ie, the lower surface of the second resin layer 220) is in direct contact with the first resin layer 210 at the interface . FIG. 1 shows that the patterned portion is in full contact with the second resin layer 220. However, it is also within the scope of the invention for the patterned portion to be in contact with at least a portion of the second resin layer 220. The uncontacted portion between the second resin layer 220 and the first resin layer 210 may be filled with air or a resin having a specific refractive index. The patterned portion may be in full contact with the second resin layer 220.

The patterned portion has at least one raised optical pattern 221 and a flat portion 222 between the immediately adjacent raised optical patterns 221. The patterned portion is configured such that a combination of the embossed optical pattern 221 and the flat portion 222 is repeatedly formed.

The optical pattern 221 may be an optical pattern having a first surface 224 formed at a top portion thereof and at least one inclined surface 223 connected to the first surface 224. The first resin layer 210 has an upper surface 210a and a lower surface 210b. The upper surface 210a of the first resin layer 210 may be an interface between the first resin layer 210 and the second resin layer 220, and may correspond to the patterned portion.

The patterned portion may satisfy the following Expression 1 and the base angle (θ) of the optical pattern 221 may be about 75° to about 90°. The base angle (θ) means an angle defined by the inclined surface 223 of the optical pattern 221 and a line corresponding to the maximum width W of the optical pattern 221, and the defined angle is in the range of about 75° to about 90°. In this case, the inclined surface 223 means an inclined surface directly connected to the flat portion 222 of the optical pattern 221. Within this range, it is possible to improve the contrast on the side surface and the contrast at the same side surface viewing angle. Specifically, the base angle (θ) may be about 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87. , 88°, 89° or 90°, for example, in the range of from about 80° to about 90°. P/W (ratio of P to W) may be about 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2, 2.5, 3.0, 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5. , 7.0, 7.5, 8.0, 8.5, 9.0, 9.5 or 10, for example, in the range of from about 1.2 to about 8. <Equation 1> 1 < P/W ≤ 10. In Expression 1, P is the pitch (unit: micrometer) of the patterned portion, and W is the maximum width (unit: micrometer) of the optical pattern.

Fig. 1 shows the case where the two base angles (?) of the optical pattern are the same. However, when the base angle (θ) is included in the range of about 75° to about 90°, optical patterns having different base angles (θ) may also be included in the scope of the present invention.

The optical pattern 221 may be an embossed optical pattern having a first surface 224 formed at a top portion thereof and at least one inclined surface 223 connected to the first surface 224. 1 shows that the optical pattern 221 is a trapezoidal optical pattern in which two adjacent inclined surfaces 223 are connected by the first surface 224, but the invention is not limited thereto. The optical pattern 221 may be an optical pattern having a rectangular cross section or a square cross section in addition to the trapezoidal cross section.

Since the first surface 224 is formed at the top portion, the light reaching the second resin layer 220 may be additionally diffused by the first surface 224 in the optical display device, thereby improving the viewing angle and brightness. Therefore, the optical diffusion effect can be improved to minimize the loss of brightness. The first surface 224 can be a flat surface and can also contribute to the fabrication of the optical film 10. However, the first surface 224 may have a fine concave or convex surface or a curved surface. When the first surface 224 is a curved surface, a lenticular lens pattern can be formed. 1 shows a pattern in which a plane is formed at a top portion (first surface) thereof, an inclined surface thereof is flat, and a cross section thereof has a trapezoidal shape (for example, a prism pattern having a triangular cross section, which is cut, that is, a cutting prism shape). However, an embossed pattern may also be included in the scope of the present invention, the embossed pattern having a shape in which the first surface is formed at the top portion and the inclined surface is a curved surface (eg, the contrast-improving layer has, for example, a truncated lenticular pattern A cut lenticular lens pattern, or a cut microlens pattern such as a truncated microlens pattern. Further, a pattern of an N-sided shape having a cross section having, for example, a rectangular shape or a square shape (where N is an integer from 3 to 20) may also be included in the scope of the present invention.

The first surface 224 may be formed to be parallel to at least one of the flat portion 222, the bottom surface of the first resin layer 210, and the top surface of the second resin layer 220 (ie, the upper surface of the second resin layer 220). 1 shows a case where the first surface 224 of the optical pattern 221, the flat portion 222 thereof, the bottom surface of the first resin layer 210, and the top surface of the second resin layer 220 are parallel to each other.

The width A of the first surface 224 can range from about 0.5 microns to about 30 microns, specifically from about 1 micron to about 15 microns. Within this range, the optical pattern 221 can be used in an optical display device, and a contrast improving effect can be expected.

The aspect ratio (H1/W) of the optical pattern 221 may range from about 0.1 to about 10, such as about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.5, 2, 2.5. , in the range of 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, 9.5 or 10, specifically in the range of from about 0.1 to about 7.0, more specifically It is in the range of from about 0.1 to about 5.0, and more specifically in the range of from about 0.1 to about 1.0. Within this range, it is possible to improve the contrast and viewing angle at the side surface of the optical display device.

The maximum height H1 of the optical pattern 221 can be greater than about 0 microns and equal to or less than about 20 microns, specifically greater than about 0 microns and equal to or less than about 15 microns, and still more specifically greater than about 0 microns and equal to or less than about 10 microns. Within this range, it is possible to improve the contrast, the viewing angle, and the brightness and prevent the occurrence of moiré.

The maximum width W of the optical pattern 221 can be greater than about 0 microns and equal to or less than about 20 microns, specifically greater than about 0 microns and equal to or less than about 15 microns, and still more specifically greater than about 0 microns and equal to or less than about 10 microns. Within this range, it is possible to improve contrast, viewing angle, brightness, and prevent ripples from occurring.

Figure 1 shows a patterned portion in which the optical patterns are formed to have the same base angle, a first surface having the same width, the same maximum height, and the same maximum width. However, adjacent optical patterns can have different base angles, first surfaces having different widths, different maximum heights, and different maximum widths.

The flat portion 222 can emit light passing through the first resin layer 210 to the second resin layer 220, thereby improving the brightness at the front side of the optical display device.

The ratio (W/L) of the maximum width W of the optical pattern 221 to the width L of the flat portion 222 may be greater than about 0 and equal to or less than about 9, such as about 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9 or 3.0, specifically between It is in the range of 0.1 to about 3, and more specifically in the range of about 0.15 to about 2. Within this range, it is possible to reduce the difference between the contrast on the front surface and the contrast on the side surface, and to improve the contrast at the same side angle of view and the contrast at the same front angle of view. In addition, the ripple phenomenon can be prevented. The width L of the flat portion 222 can range from about 1 micron to about 50 microns, and specifically from about 1 micron to about 20 microns. Within this range, it is possible to improve the brightness at the front side of the optical display device.

The maximum width W of one optical pattern 221 and the flat portion 222 of the optical pattern 221 form a pitch P. The pitch P can range from about 1 micron to about 50 microns, and specifically from about 1 micron to about 40 microns. Within this range, it is possible to improve the contrast and prevent ripples.

Figure 1 shows that adjacent patterned portions have the same pitch and the same maximum width, but adjacent patterned portions can have different pitches and different maximum widths.

The refractive index of the first resin layer 210 can be greater than about 0 and less than about 1.52, specifically greater than or equal to about 1.35 and less than about 1.50. Within this range, it is possible to improve the light diffusion effect, contribute to the manufacture of optical display devices and significantly improve polarized light diffusion and contrast.

The first resin layer 210 may be made of a composition for the first resin layer, the composition comprising a curable resin. The composition for the first resin layer may further contain an initiator. The curable resin and the initiator are the same as the curable resin and initiator of the composition for the second resin layer to be described below. The composition for the first resin layer may further contain an additive to be used in the composition for the second resin layer described below.

In an exemplary embodiment, the first resin layer 210 may be a non-adhesive layer that does not have an adhesive force. When the first resin layer 210 is a non-stick layer, the optical film 10 may be stacked on the adhesive (for example, a polarizing film) via an adhesive, a bonding agent, or a viscous bonding agent.

In another exemplary embodiment, the first resin layer 210 may have adhesive properties. When the first resin layer 210 has an adhesive property, the optical film 10 can be stacked on the adhesive without an additional adhesive, a binder or a viscous bond, thereby reducing the thickness of the optical film 10.

In an exemplary embodiment, the first resin layer 210 may not include the metal complex dye and the organic black dye to be described below.

Although not shown in FIG. 1, FIG. 1 shows that the optical pattern 221 is formed to be elongated in a strip shape in the longitudinal direction of the optical pattern 221. However, the optical pattern 221 may be formed in a dot shape. The term "dot" means that the optical patterns 221 are spaced apart from each other and dispersed. Preferably, the optical pattern 221 is formed to be elongated in a strip shape such that the viewing angle is widened from the left or right.

The refractive index of the second resin layer 220 is greater than the refractive index of the first resin layer 210. Therefore, the contrast improving layer 200 can improve the contrast on the side surface by diffusing and emitting light incident from the light incident surface of the first resin layer 210. Although the contrast on the side surface is improved, it is possible to minimize the reduction in contrast on the front surface, reduce the difference between the contrast on the front surface and the contrast on the side surface, and improve the same side angle of view. Contrast and contrast at the same front angle of view. The difference in refractive index between the second resin layer 220 and the first resin layer 210 may be greater than or equal to about 0.05, such as about 0.05, 0.1, 0.15, 0.2, 0.25, or 0.3, specifically ranging from about 0.05 to about 0.3. And more specifically in the range of from about 0.05 to about 0.2. Within this range, it is possible to significantly improve concentrated light diffusion and contrast.

The refractive index of the second resin layer 220 can be greater than or equal to about 1.50, such as about 1.50, 1.55, 1.60, 1.65, or 1.70, and specifically from about 1.55 to about 1.70. Within this range, it is possible to improve the light diffusion effect.

The second resin layer 220 may include at least one of a metal complex dye and an organic black dye, and includes a composition for the second resin layer, the composition including a curable resin.

After dispersing at least one of the metal complex dye and the organic black dye, the average particle diameter (D50) may be greater than about 0 nm and equal to or less than about 100 nm, such as about 5 nm, 10 nm, 15 Nano, 20 nm, 25 nm, 30 nm, 35 nm, 40 nm, 45 nm, 50 nm, 55 nm, 60 nm, 65 nm, 70 nm, 75 nm 80 nm, 85 nm, 90 nm, 95 nm or 100 nm, and preferably in the range of from about 5 nm to about 80 nm. Within this range, it is possible to obtain the effects of the present invention.

The average particle diameter of the metal complex dye and the organic black dye may be significantly smaller than each of the maximum width W of the optical pattern 221 and the width L of the flat portion 222. For example, the ratio of the average particle diameter of the metal complex dye or the organic black dye to the maximum width W of the optical pattern 221, the width L of the flat portion 222, or the width A of the first surface 224 of the optical pattern 221 (ie, metal Average particle diameter of the complex dye or organic black dye: the maximum width W of the optical pattern 221, the width L of the flat portion 222, or the width A) of the first surface 224 of the optical pattern 221 may be between about 1:500 and about 1 Within the range of 800, and preferably in the range of from about 1:600 to about 1:800. Within this range, it is possible to obtain the effects of the present invention.

The second resin layer 220 may include at least one of a metal complex dye having an average particle diameter and an organic black dye, thereby improving contrast on the front surface, reducing reflectance, and reducing color shift on the side surface. In this range of the average particle diameter, when the metal complex dye or the organic black dye is present between the adjacent optical patterns 221, the movement of light emitted from the flat portion 222 of the first resin layer 220 is not affected. The contrast on the front surface is improved, and the light emitted to the side surface of the pattern is unaffected by the patterned portion to also improve the contrast on the side surface. The second resin layer 220 may contain a metal complex dye or an organic black dye, thereby improving the contrast on the side surface and reducing the reflectance which can be increased by increasing the layer. It is possible to increase the low visibility of black caused by the side light leakage of the LCD panel. The panel reflectance measured at the protective layer 100 relative to the optical film 10 can be less than about 5%, preferably from about 0% to about 4.95%, and more preferably from about 0% to about 4.9%. Within the scope. Within this range, the reflectance can be lowered to improve the appearance.

In an exemplary embodiment, the content of at least one of the metal complex dye and the organic black dye may be from about 0.01% by weight to about 10% by weight, for example, about 0.01%, relative to the weight of the second resin layer 220. % by weight, 1% by weight, 2% by weight, 3% by weight, 4% by weight, 5% by weight, 6% by weight, 7% by weight, 8% by weight, 9% by weight or 10% by weight, preferably about 0.01% by weight % by weight to about 5.0% by weight, from about 0.01% by weight to about 3.0% by weight or from about 0.01% by weight to about 2.0% by weight, more preferably from about 0.01% by weight to about 1.0% by weight, and most preferably about From 0.01% by weight to about 0.5% by weight. Within this range of amounts, it is possible to improve the front contrast, reduce the reflectance, increase the visibility of black, and add a metal complex dye or an organic black dye to the second resin layer 220. In addition, it is possible to obtain an excellent dispersion effect of the dye and prevent the light transmittance of the second resin layer 220 from being reduced.

The light transmittance of the second resin layer 220 may range from about 50% to about 92%, and preferably from about 75% to about 85%, at a wavelength of 550 nm. Within this range, it is possible to improve the contrast on the side surface (caused by the pattern) and the contrast on the front surface.

Although not shown in FIG. 1, at least one of the metal complex dye and the organic black dye may be contained throughout the second resin layer 220. That is, the space between the immediately adjacent embossed optical patterns 220 in the second resin layer 220 is defined as a "first region" and will be connected to the virtual surface of the first surface 224 of the embossed optical pattern 220 that is spaced apart from each other. When the space between the surface and the lower surface of the protective layer 100 is defined as the "second region", the second resin layer 220 may have a first region and a second region, and the first region and the second region may be in contact with each other And at least one of the metal complex dye and the organic black dye may be included in both the first zone and the second zone. In this case, the second resin layer 220 can be easily manufactured. 2 shows the first region 220a and the second region 220b of the second resin layer 220 in the optical film 10 described above.

Hereinafter, the metal complex dye will be described in detail.

The metal complex dye may comprise a metal-containing black dye.

The metal complex dye may comprise at least one of a 1:1 metal complex dye and a 1:2 metal complex dye. A 1:1 metal complex dye means a dye in which one metal atom is bonded to one dye molecule. A 1:2 metal complex dye means a dye in which one metal atom is combined with two dye molecules.

The metal may be chromium, nickel, cobalt or copper, but the invention is not limited thereto.

The dye molecule may contain an azo-based molecule (for example, a monoazo-based molecule) containing at least one selected from the group consisting of a hydroxyl group, a carboxyl group, and an amine group. Therefore, it is possible to further improve the contrast on the side surface (caused by the pattern) and improve the contrast on the front surface (caused by the metal complex dye), and further reduce the reflectance and further increase the visibility of black.

In an exemplary embodiment, the metal complex dye may be a metal-containing azo dye and may have a C ₆ -C ₂₀ monocyclic aromatic functional group or a polycyclic aromatic functional group. Preferably, the metal complex dye may comprise a C ₈ -C ₁₅ monocyclic aromatic functional group or a polycyclic aromatic functional group such as a phenyl or naphthyl group as a monocyclic aromatic functional group or a polycyclic aromatic functional group. . Therefore, when the metal complex dye is mixed with the UV curable resin forming the second resin layer 220, the UV curable resin can be sufficiently cured, thereby increasing the hardness of the second resin layer 220 and preventing the metal complex dye and the first The two resin layers 220 are separated.

In an exemplary embodiment, the metal complex dye can comprise one type of dye.

In another exemplary embodiment, the metal complex dye may comprise a mixture of a red metal complex dye, a green metal complex dye, and a blue metal complex dye.

The metal complex dye may have a refractive index in the range of from about 1.6 to about 2.2, such as in the range of about 1.6, 1.7, 1.8, 1.9, 2.0, 2.1 or 2.2, and preferably in the range of from about 1.9 to about 2.1. . Within this range, when the metal complex dye is contained in the second resin layer 220, the refractive index of the second resin layer 220 may not be lowered.

The metal complex dye is not particularly limited, but a commercially available product can be used as a metal complex dye. For example, at least one of Orasol® Black X55 (manufactured by BASF Company) and Orasol® Black X51 (manufactured by BASF Corporation) can be used as the metal complex dye.

Hereinafter, the organic black dye will be described in detail.

The organic black dye may be a non-metal based dye that does not contain a metal, and may include a black dye containing only organic molecules.

The organic black dye has high dispersibility (minimum dispersion unit of 1 nm to 5 nm), high transparency, and high brightness. On the other hand, an inorganic black dye containing carbon black and the like is inferior in dispersibility (minimum dispersion unit is from 50 nm to 400 nm) and is opaque. Organic black dyes are superior to inorganic black dyes, ie, carbon black, due to the high dispersion, reduced brightness, and high transmission of several nanometers suitable for micropattern size and solventless printing procedures.

The organic black dye may have a refractive index in the range of from about 1.6 to about 2.2, such as in the range of about 1.6, 1.7, 1.8, 1.9, 2.0, 2.1 or 2.2, and preferably in the range of from about 1.9 to about 2.1. Within this range, when the organic black dye is contained in the second resin layer 220, the refractive index of the second resin layer 220 may not be lowered.

In an exemplary embodiment, the organic black dye can be a trichromatic dye mixture. For example, the trichrome dye mixture can be a mixture of a first dye (orange dye), a second dye (red dye), and a third dye (blue dye). The first dye, the second dye, and the third dye may have different maximum absorption wavelengths. The "maximum absorption wavelength" is a value measured at a concentration of each of the first to third dyes in the solvent (i.e., methyl ethyl ketone) of 5 mg/liter (5% by weight). The range of concentrations can be considered as the concentration suitable for measuring the transmittance.

The first dye can comprise a dye having a maximum absorption wavelength of from about 430 nanometers to about 450 nanometers, and preferably about 440 nanometers, and an absorption wavelength ranging from about 360 nanometers to about 640 nanometers.

The second dye can comprise a dye having a maximum absorption wavelength of from about 510 nm to about 530 nm and preferably about 520 nm and an absorption wavelength ranging from about 360 nm to about 740 nm.

The third dye can comprise a dye having a maximum absorption wavelength of from about 590 nanometers to about 610 nanometers and preferably about 600 nanometers and an absorption wavelength ranging from about 360 nanometers to about 740 nanometers.

In an exemplary embodiment, the organic black dye may be a mixture in which the first dye is present in an amount of from about 30% by weight to about 50% by weight, based on the total weight of the organic black dye, for example, in an amount of about 30% by weight, 35% by weight, 40% by weight, 45% by weight or 50% by weight and preferably in an amount of from about 40% by weight to about 50% by weight, and the second dye is present in an amount of from about 1% by weight to about 20% by weight For example, the content is about 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12 By weight, 13%, 14%, 15%, 16%, 17%, 18%, 19% or 20% by weight and preferably from about 1% to about 10% by weight, And the content of the third dye is from about 30% by weight to about 50% by weight, for example, the content is about 30% by weight, 35% by weight, 40% by weight, 45% by weight or 50% by weight, and preferably the content is about 40% by weight. Up to about 50% by weight. Within this range, it is possible to obtain a black dye having high brightness.

The first dye (orange dye) may comprise an azo dye, such as an aromatic azo dye. For example, a dye represented by the following formula 1 (for example, Synolon yellow Brown K-2RS manufactured by Kyungin Synthetic Corporation) can be used as the first dye, but The present invention is not limited to this: <Formula 1> .

The second dye (red dye) may comprise an azo dye, such as an aromatic azo dye. For example, a dye represented by the following formula 2 (for example, Synolon rubine K-GFL manufactured by Kyoko No. 1 Co., Ltd.) can be used as the second dye, but the present invention is not limited thereto: <Formula 2> .

The third dye (blue dye) may contain an azo dye such as an aromatic azo dye. For example, a dye represented by the following formula 3 (for example, Synolon navy blue K-GLS manufactured by Kyung Nippon Co., Ltd.) can be used as the third dye, but the present invention is not limited thereto. : <式3> .

The organic black dye is not particularly limited, and a commercially available product can be used as an organic black dye. For example, BS01 (manufactured by Kyung Nippon Co., Ltd.), BS02 (manufactured by Kyojin Electronics Co., Ltd.), or the like can be used as the organic black dye.

The curable resin may include at least one of a UV curable resin and a thermosetting resin. However, preferably, the use of the UV curable resin causes the second resin layer 220 to be formed in a short time and the pattern shape is excellent at the time of pattern formation. The curable resin may comprise a (meth)acrylic monomer, oligomer or resin. Since the resin has a high refractive index, the curable resin may contain a resin having a repeating unit as a main framework derived from a compound having a benzene ring structure.

After the curable resin is cured, its refractive index can be greater than or equal to about 1.55, and preferably from about 1.58 to about 1.62. Within this range, it is possible to ensure the refractive index of the second resin layer 220.

The composition for the second resin layer may further contain an initiator. An initiator can be used to cure the curable resin and can include at least one of a photoinitiator and a thermal initiator. Any conventional type known to those skilled in the art can be used as the photoinitiator and thermal initiator. The photoinitiator can comprise one selected from the group consisting of phosphorus, triazine, acetophenone, benzophenone, thioxanthone, benzoin, anthraquinone, phenylketone initiators, and mixtures thereof. The initiator may be included in an amount of from about 0.01% by weight to about 5% by weight based on the solid content of the second resin layer 220 or the composition for the second resin layer, for example, the content is greater than about 0.5% by weight and equal to or less than about 5% by weight, or the content is from about 2% by weight to about 5% by weight. Within this range, the composition for the second resin layer can be sufficiently cured, and the remaining amount of the initiator can prevent the light transmittance of the contrast improving layer 200 from being lowered.

For the coatability of the composition, the composition for the second resin layer may contain a conventional solvent such as ethanol (EtOH), propylene glycol monomethyl ether acetate (PGME), methyl group. Methyl ketone (MEK) and methyl isobutyl ketone (MIBK), but the invention is not limited thereto.

The composition for the second resin layer may further comprise conventional additives known to those skilled in the art. The additive may comprise at least one selected from the group consisting of a leveling agent, a surface control agent, an antioxidant, an antifoaming agent, an ultraviolet absorber, and a light stabilizer.

The second resin layer 220 may have a maximum thickness of greater than about 0 microns and equal to or less than about 30 microns, such as greater than about 0 microns and equal to or less than about 20 microns. Within this range, it is possible to prevent the occurrence of, for example, curling of the curl.

The difference between the maximum thickness of the second resin layer 220 and the maximum height of the optical pattern 221 (also referred to as "wall thickness") may be greater than about 0 microns and equal to or less than about 30 microns, such as greater than about 0 microns and equal to or less than About 20 microns, or greater than about 0 microns and equal to or less than about 10 microns. Within this range, it is possible to minimize the reduction in contrast on the side surfaces.

In an exemplary embodiment, the second resin layer 220 may not contain carbon black.

In an exemplary embodiment, the first resin layer 210 may not contain carbon black.

The thickness of the contrast-improving layer 200 can range from about 10 microns to about 100 microns, specifically from about 10 microns to about 50 microns, and more specifically from about 10 microns to about 40 microns. . Within this range, the contrast improving layer 200 can be used in an optical display device.

The contrast improving layer 200 can be prepared by a conventional method known to those skilled in the art. For example, the contrast improving layer 200 may be formed by coating the protective layer 100 with a composition for the second resin layer, coating and curing the optical pattern 221 and the flat portion 222 to form the second resin layer 220, And coating and curing the composition for the first resin layer, but the invention is not limited thereto.

Hereinafter, an optical film according to another exemplary embodiment of the present invention will be described.

An optical film according to the present exemplary embodiment and an optical film according to the present invention, except that the second resin layer does not contain a metal complex dye or an organic black dye and the first resin layer contains at least one of a metal complex dye and an organic black dye The optical film 10 of the exemplary embodiment is the same.

The content of at least one of the metal complex dye and the organic black dye may be from about 0.01% by weight to about 10% by weight, for example, about 0.01% by weight, 1% by weight, and 2 parts by weight relative to the weight of the first resin layer. %, 3% by weight, 4% by weight, 5% by weight, 6% by weight, 7% by weight, 8% by weight, 9% by weight or 10% by weight, preferably in an amount of from about 0.01% by weight to about 5.0% by weight, 0.01 The weight% to 3.0% by weight or 0.01% by weight to 2.0% by weight, and more preferably the content is from about 0.01% by weight to about 1.0% by weight. Within this range, it is possible to improve the contrast on the front surface, increase the visibility of black, reduce the reflectance, obtain high transmittance, and obtain an excellent diffusion effect of the metal composite. The details of the metal complex dye and the organic black dye are the same as those described above.

In an exemplary embodiment, the second resin layer may not contain carbon black.

In an exemplary embodiment, the first resin layer may not contain carbon black.

Hereinafter, an optical film according to another exemplary embodiment of the present invention will be described.

In the optical film according to the present exemplary embodiment, the second resin layer may include at least one of a metal complex dye and an organic black dye. At least one of the metal complex dye and the organic black dye may be contained only in the first region of the second resin layer and not included in the second region of the second resin layer. Since the metal complex dye or the organic black dye is contained in a specific region, it is possible to further improve the contrast and brightness and prevent the light transmittance of the second resin layer from decreasing.

The content of at least one of the metal complex dye and the organic black dye may be from about 0.01% by weight to about 10% by weight, for example, about 0.01% by weight, 1% by weight, and 2 parts by weight relative to the weight of the second resin layer. %, 3% by weight, 4% by weight, 5% by weight, 6% by weight, 7% by weight, 8% by weight, 9% by weight or 10% by weight, preferably in an amount of from about 0.1% by weight to about 5.0% by weight, preferably From 0.01% by weight to about 3.0% by weight or from about 0.01% by weight to about 5% by weight, and more preferably from about 0.01% by weight to about 1.0% by weight. Within this range, it is possible to improve the contrast on the front surface, increase the visibility of black, reduce the reflectance, obtain high transmittance, obtain excellent diffusion effects of the metal composite, and remove the first and second regions. The difference in refractive index between. The details of the metal complex dye and the organic black dye are the same as those described above.

In an exemplary embodiment, the absolute value of the refractive index difference between the first zone and the second zone may range from about 0.02 to about 0.20, and preferably from about 0.08 to about 0.20. Within this range, the refractive index difference between the first region and the second region can be reduced to prevent the light transmittance of each of the second resin layer, the optical film, and the polarizing plate from being reduced.

In an exemplary embodiment, the second resin layer may not contain carbon black.

In an exemplary embodiment, the first resin layer may not contain carbon black.

A polarizing plate according to an exemplary embodiment of the present invention will be described with reference to FIG. FIG. 3 is a cross-sectional view showing a polarizing plate according to an exemplary embodiment of the present invention.

Referring to FIG. 3, the polarizing plate 20 may include a polarizing film 300 and an optical film. The optical film may comprise an optical film 10 in accordance with an illustrative embodiment of the invention. An optical film may be formed on the light exit surface of the polarizing film 300. The optical film can diffuse the polarized light that passes through the polarizing film 300, thereby improving front contrast, side contrast, and viewing angle, and increasing black visibility.

The polarizing film 300 may polarize light incident from the liquid crystal panel and transmit the polarized light to the contrast improving layer 200. The polarizing film 300 is formed on the light incident surface of the contrast improving layer 200.

The polarizing film 300 may include a polarizer. Specifically, the polarizer may include a polyvinyl alcohol-based polarizer produced by stretching a polyvinyl alcohol-based film in one direction, or a polyene-based polarizer produced by dehydrating a polyvinyl alcohol-based film. The thickness of the polarizer can range from about 5 microns to about 40 microns. Within this range, the polarizer can be used in an optical display device.

The polarizing film 300 may include a polarizer and a protective layer formed on at least one surface of the polarizer. The protective layer protects the polarizer, thereby improving the reliability of the polarizing plate and increasing the mechanical strength of the polarizing plate. The protective layer may include at least one of an optically transparent protective film and a protective coating. The description of the protective layer is the same as those described above.

The polarizing plate can be formed through a conventional method. For example, a polarizing plate can be manufactured by preparing an optical film by the method described above, and attaching the polarizing film to the other surface of the protective layer. The attachment can be performed by using at least one of a generally known water-based adhesive and a photocurable adhesive.

The liquid crystal display device of the present invention may comprise the polarizing plate of the present invention. In an exemplary embodiment, the liquid crystal display device may include a polarizing plate as a polarizing plate at a visible side with respect to the liquid crystal panel. The "polarizing plate at the visible side" is disposed opposite to the screen (i.e., the light source) with respect to the liquid crystal panel.

In an exemplary embodiment, the liquid crystal display device may include a backlight unit, a first polarizing plate, a liquid crystal panel, and a second polarizing plate that are sequentially stacked. The second polarizing plate may include the polarizing plate of the present invention. The liquid crystal panel can use a vertical alignment (VA) mode, an in-plane switching (IPS) mode, a patterned vertical alignment (PVA) mode, or a super-patterned vertical alignment. ; S-PVA) mode, but the invention is not limited thereto. In an exemplary embodiment, the liquid crystal display device may include a polarizing plate as a polarizing plate at a side opposite to a light source of the liquid crystal panel. The "polarizing plate at the light source side" is disposed at the light source side with respect to the liquid crystal panel. In another exemplary embodiment, both of the polarizing plate at the visible side with respect to the visible side of the liquid crystal panel and the polarizing plate at the light source side 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 the exemplary embodiments of the present invention. However, it is to be understood that the following exemplary embodiments are provided for the purpose of illustration only and are not intended to limit the invention.

Instance 1

0.15 parts by weight of the dye was mixed into 100 parts by weight of the UV curable resin, and the resulting mixture was stirred at 2,000 rpm for 2 hours by using a disperser to prepare a composition for the second resin layer. The dye is Orasol® Black X55 (manufactured by BASF, average particle diameter (D50) is 10 nm, powder, and chromium metal: azo compound is a 1:2 complex salt), the UV curable The resin is SSC5760 (manufactured by SHIN-A T&C).

100 parts by weight of the acrylic copolymer (i.e., binder PL8540) was mixed with 80 parts by weight of a diluent solvent (i.e., methyl ethyl ketone), and the resulting mixture was stirred at 500 rpm by using a stirrer. Minutes to prepare a composition for the first resin layer.

The prepared composition for the second resin layer is coated on one surface (light incident surface) of the protective layer to prepare a coating layer, that is, a polyethylene terephthalate (PET) film (TA044 manufactured by Toyobo Company, thickness 80 microns). The optical pattern and the flat portion are applied onto the coating by using a film in which the optical pattern and the flat portion are alternately formed, and the optical pattern is UV-cured at a light amount of 500 mJ/cm ² and The flat portion to form a second resin layer.

The prepared composition for the first resin layer was coated on one surface of the prepared second resin layer and dried in a drying oven at a temperature of 90 ° C for 4 minutes to form a first resin layer, thereby fabricating optical membrane. The first resin layer has a bonding property and a refractive index lower than a refractive index of the second resin layer. The dye is contained in the entire second resin layer (two of the first zone and the second zone) in the optical film.

Table 1 below shows the specifications of the patterned portion of the contrast improving layer.

One surface of the first resin layer of the optical film was laminated on the surface of a PET film of a polarizing film (product name: AMN-6143CPS (CO)) to manufacture a polarizing plate having PET manufactured by Samsung SDI /PVA/COP three-layer structure.

Instance 2

An optical film and a polarizing plate were produced in the same manner as in Example 1, except that 0.3 part by weight of Orasol® black X55 was used in forming the composition for the second resin layer. The dye is contained in the entire second resin layer (two of the first zone and the second zone) in the optical film.

Instance 3

An optical film and a polarizing plate were produced in the same manner as in Example 1, except that in the composition for forming the second resin layer, 100 parts by weight of a resin (i.e., ECOKOT-H903 (by NC Chemistry (NC Chem) was used. )))) Replace 100 parts by weight of SSC5760 (manufactured by Shinan, Korea) and 0.15 parts by weight of Orasol® black X51 (manufactured by BASF, average particle diameter (D50) of 10 nm, powder, and chrome metal: The azo compound is a 1:2 complex salt) in place of 0.15 parts by weight of Orasol® Black X55. The dye is contained in the entire second resin layer (two of the first zone and the second zone) in the optical film.

Instance 4

An optical film and a polarizing plate were produced in the same manner as in Example 1, except that 0.3 part by weight of Orasol® black X51 was used as a black dye instead of 0.15 part by weight of Orasol® black in the composition for forming the second resin layer. X55. The dye is contained in the entire second resin layer (two of the first zone and the second zone) in the optical film.

Instance 5

An optical film and a polarizing plate were produced in the same manner as in Example 1, except that 0.15 parts by weight of an organic black dye (average particle diameter of 10 nm) was used instead of 0.15 by weight in the composition for forming the second resin layer. Orasol® Black X55. By using 45% by weight of an orange dye (i.e., Western European Longan Brown K-2RS (manufactured by Kyokobe Co., Ltd.)), 10% by weight of a red dye (i.e., Western Omega Red G-GEL (by Kyoko-yeon Co., Ltd.) An organic black dye which is a three-color dye mixture is prepared by mixing a blue dye (i.e., 45 wt% of Western European Long Deep Blue K-GLS (manufactured by Kyojin Co., Ltd.)). Figure 5 shows the transmittance according to the wavelength of each color dye. The dye is contained in the entire second resin layer (two of the first zone and the second zone) in the optical film.

Instance 6

A UV curable resin, SSC5760 (manufactured by Shinan, Korea), was used as a composition for the second resin layer.

100 parts by weight of an acrylic copolymer (ie, binder resin PL8540) and 0.038 parts by weight of Orasol® black X55 (manufactured by BASF Corporation, an average particle diameter of 10 nm) and 80 parts by weight of a diluent solvent (ie, methyl group B) The base was mixed, and the resulting mixture was stirred at 500 rpm for 30 minutes by using a stirrer to prepare a composition for the first resin layer.

The prepared composition for the second resin layer was coated on one surface (light incident surface) of the protective layer to prepare a coating layer, that is, a PET film (TA044 manufactured by Toyobo Co., Ltd., thickness 80) Micron). The optical pattern and the flat portion are applied onto the coating by using a film in which the optical pattern and the flat portion are alternately formed, and the optical pattern and the flat portion are UV-cured at a light amount of 500 mJ/cm to form The second resin layer.

The prepared composition for the first resin layer was coated on one surface of the prepared second resin layer and dried in a drying oven at a temperature of 90 ° C for 4 minutes to form a first resin layer, thereby fabricating optical membrane. The first resin layer has a bonding property and a refractive index lower than a refractive index of the second resin layer.

A polarizing plate was manufactured by using an optical film in the same manner as in Example 1.

Instance 7

An optical film and a polarizing plate were produced in the same manner as in Example 6, except that 0.076 parts by weight of Orasol® Black X55 was used in forming the composition for the first resin layer.

Instance 8

100 parts by weight of the acrylic copolymer (i.e., the binder resin PL8540) was mixed with 80 parts by weight of a diluent solvent (i.e., methyl ethyl ketone), and the resulting mixture was stirred at 500 rpm by using a stirrer. Minutes to prepare a composition for the first resin layer.

100 parts by weight of a UV curable resin, that is, SSC5760 (manufactured by Shinan, Korea), was used as a composition for the second region of the second resin layer.

A certain amount of the dye was mixed into 100 parts by weight of the UV curable resin, and the resulting mixture was stirred at 2,000 rpm for 2 hours by using a disperser to serve as a combination of the first region for the second resin layer. The dye, Orasol® Black X55 (manufactured by BASF, having an average particle diameter (D50) of 10 nm, a powder, and a chromium metal: azo compound is a 1:2 complex salt), UV curable resin is SSC5760 (Xinan, Korea).

The composition for the first resin layer was coated on a PET film surface (light-emitting surface) of a polarizing film (product name: AMN-6143CPS (CO)) to prepare a coating layer, which was manufactured by Samsung SDI PET / PVA / COP three-layer structure. The optical pattern and the flat portion are applied onto the coating by using a film in which the optical pattern and the flat portion are alternately formed, and the optical pattern and the flat portion are UV-cured at a light amount of 500 mJ/cm to form The first resin layer.

The prepared composition for the first region of the second resin layer is coated only between the optical patterns of the first resin layer. The prepared composition for the second region of the second resin layer is coated on the coating layer. UV curing was performed at a light amount of 500 mJ/cm 2 to manufacture a polarizing plate.

Table 1 below shows the specifications of the patterned portion of the contrast improving layer. The dye is contained only in the first region of the second resin layer and is not contained in the second region of the second resin layer. In the composition for forming the first region for the second resin layer, Orasol® Black X55 was added to the second resin layer of the finally manufactured polarizing plate so as to have the contents shown in Table 2 below.

Instance 9

A polarizing plate was produced in the same manner as in Example 8, except that Orasol® Black X55 was added to the second resin layer so as to have the contents shown in Table 2 below.

Instance 10

A polarizing plate was produced in the same manner as in Example 8, except that Orasol® black X51 was used instead of Orasol® black X55, and Orasol® black X51 was added to the second resin layer so as to have the contents shown in Table 2 below. .

Comparative example 1

A polarizing plate (product name: AMN-6143CPS (CO)) having a PET/PVA/COP structure manufactured by Samsung SDI and containing no optical film was used.

Comparative example 2

An optical film and a polarizing plate were produced in the same manner as in Example 1, except that the second resin layer did not contain Orasol® Black X55.

Comparative example 3

An optical film and a polarizing plate were produced in the same manner as in Example 1, except that 0.5 part by weight of a light absorber was used instead of 0.15 parts by weight of Orasol® Black X55 used in forming a composition for the second resin layer. The light absorbing agent (xx-2740 manufactured by Sekisui Company, having an average diameter (D50) of 6 μm) is coated with a light absorbing layer containing acrylic light diffusion on the surface thereof. Body carbon black.

Comparative example 4

An optical film and a polarizing plate were produced in the same manner as in Example 6, except that 0.5 part by weight of a light absorber was used in the composition for forming the second resin layer instead of 0.15 part by weight of Orasol used as a light absorber. ® Black X55, the light absorbing agent (xx-2740 manufactured by Sekisui Co., Ltd., having an average diameter (D50) of 6 μm) coated with a light absorbing layer containing acrylic light diffusion on the surface thereof Body carbon black.

[Table 1]

The physical properties of each of the polarizing plate and the optical film of the examples and the comparative examples were evaluated. The evaluation results are shown in Table 2, Table 3, and Figure 4 below.

Panel reflectance: The optical film laminated on the polarizing film of the examples and the comparative examples was laminated on the SUHD 55 having the LCD VN type manufactured by Samsung Electronics by using a binder having a refractive index of 1.46 to 1.50. On the LCD panel, and then, by using a reflectance meter (ie, a spectrophotometer (CM-2600D manufactured by Konica Minolta)) in the SCI reflection mode (light source: D65 light source) The reflectance is measured in the wavelength range of 320 nm to 800 nm. The Y (D65) value of the measured value is measured.

Manufacturing a polarizing plate at the side of the light source

The polyvinyl alcohol film was elongated at a temperature of 60 ° C to three times its original length, adsorbed with iodine, and then elongated to 2.5 times its elongation length in an aqueous boric acid solution having a temperature of 40 ° C to prepare a polarizer. The bottom layer, a triethylene fluorene cellulose film (thickness 80 μm), was bonded to both surfaces of the polarizer by using a polarizing plate adhesive (Z-200 manufactured by Nippon Goshei Company). Each one to make a polarizing plate. The manufactured polarizing plate was used as a polarizing plate at the side of the light source.

Manufacturing a module for a liquid crystal display device

Each of the manufactured polarizing plate at the light source side, the liquid crystal panel (PVA mode), and the polarizing plates manufactured in the examples and the comparative examples was sequentially assembled to manufacture a module for a liquid crystal display device. The protective layer was assembled so as to be placed at the outermost position of each of the polarizing plates manufactured in the examples and the comparative examples.

A light-emitting diode (LED) light source, a light guide plate, and a module for a liquid crystal display device are assembled to manufacture a liquid crystal display device, except for the configuration of a module for a liquid crystal display device in the examples and comparative examples In addition, the liquid crystal display device further includes an edge type LED light source (having the same configuration as the Samsung TV (55 inches), and the model name: UN55KS8000F manufactured in 2016).

By using EZ CONTRAST X88RC (EZXL-176R-F422A4 manufactured by ELDIM Company) on the front surface (0°, 0°) and side surface (0°, 80°) of the spherical coordinate system The front brightness is measured in each of the white mode and the black mode.

The relative contrast on the front surface is calculated as the ratio of the brightness of the white mode to the brightness value of the black mode in the spherical coordinate system (0°, 0°). The contrast on the side surface is calculated as the ratio of the brightness of the white mode to the brightness value of the black mode in the spherical coordinate system (0°, 80°).

The front relative luminance in the white mode is calculated as the ratio of the luminance of the corresponding example or the comparative example in the white mode to the luminance of the comparative example 1. The front relative luminance in the black mode is calculated as the ratio of the luminance of the corresponding example or the comparative example in the black mode to the luminance of Comparative Example 1.

The skin tone shift was evaluated by using EZCONTRAST X88RC (EZXL-176R-F422A4 manufactured by Eldim Corporation). A low skin tone shift means excellent properties.

The appearance of the optical film was evaluated to be good when the strip pattern and the unusual features were not visible in the appearance. When a strip pattern or a convex surface is produced, the appearance is evaluated as defective.

The light transmittance of the polarizing plate was evaluated by using a V7100 manufactured by Jasco Company.

[Table 2]

[table 3]

As shown in Table 2, the optical film of the present invention can improve front contrast and side contrast, reduce reflectance, and reduce side color shift. In particular, the optical film of the present invention can allow a front contrast ratio of greater than 70% and a reflectance of less than 5%. The optical film of the present invention has an excellent appearance since each layer is sufficiently cured and the dye is sufficiently dissolved and mixed.

Accordingly, the present invention provides an optical film capable of improving front contrast and reducing reflectance. The present invention provides an optical film capable of reducing side color shift. The present invention provides an optical film which has an excellent appearance by sufficiently curing a composition for a high refractive index layer and sufficiently dissolving and mixing the dye in a high refractive index resin. The present invention provides an optical film which has an excellent appearance due to sufficiently curing a composition for a low refractive index layer and sufficiently dissolving and mixing the dye in a low refractive index resin. The present invention provides an optical film capable of reducing light leakage to a side surface by reducing light emitted to a side surface in a black mode, and improving contrast in a black mode. The present invention relates to an optical film comprising a second resin layer having improved brightness and having high light transmittance (although containing a dye). The present invention provides a polarizing plate and an optical display device, the polarizing plate and the optical display device comprising the optical film of the present invention, the polarizing plate and the optical display device capable of improving side contrast, reducing reflectance, and increasing black Visibility.

On the other hand, Comparative Example 3 and Comparative Example 4 containing carbon black were inferior in appearance, high in height side color shift, and high in panel reflectance, and thus black visibility was low. In addition, referring to FIG. 4, when carbon black (shown in a circle in FIG. 4) is contained, carbon black does not match the pattern size, and thus the effects of the present invention may not be obtained.

All of these simple variations and modifications of the embodiments can be made by those skilled in the art, and all such modifications that fall within the scope of the invention are intended to be included within the scope of the appended claims.

10‧‧‧Optical film

20‧‧‧Polar plate

100‧‧‧protection layer

200‧‧‧Contrast modified layer

210‧‧‧First resin layer

210a‧‧‧ upper surface

210b‧‧‧ lower surface

220‧‧‧Second resin layer

220a‧‧‧First District

220b‧‧‧Second District

221‧‧‧ optical pattern

222‧‧‧flat part

223‧‧‧Sloping surface

224‧‧‧ first surface

300‧‧‧ polarizing film

A‧‧‧The width of the first surface

H1‧‧‧Maximum height of optical pattern

L‧‧‧Width of the flat part

P‧‧‧ spacing

W‧‧‧Maximum width of optical pattern

Θ‧‧‧ bottom angle

The above and other objects, features and advantages of the present invention will become apparent to those skilled in the <

FIG. 1 is a cross-sectional view showing an optical film according to an exemplary embodiment of the present invention. 2 shows a first region and a second region of a second resin layer in the optical film of the present invention. FIG. 3 is a cross-sectional view showing a polarizing plate according to an exemplary embodiment of the present invention. 4 is a scanning electron microscope (SEM) image of a cross section of an optical film according to Comparative Example 4. Fig. 5 shows the transmittance (TT) according to each of the wavelengths of the dyes contained in the organic black dye and shows the organic black dye used in the examples.

Claims (20)

An optical film comprising: a protective layer; and a contrast improving layer comprising a second resin layer and a first resin layer facing the second resin layer, the second resin layer and the first resin layer Sequentially stacked from a lower surface of the protective layer, wherein a refractive index of the second resin layer is greater than a refractive index of the first resin layer, and the first resin layer faces the second resin layer thereof At least a portion having a patterned portion having at least two raised optical patterns and a flat portion between the raised optical pattern and the immediately adjacent raised optical pattern, wherein the raised optical pattern The base angle is in the range of 75° to 90°, and the patterned portion satisfies the following Expression 1: <Expression 1> 1 < P/W ≤ 10, wherein, in Equation 1, P is in microns a pitch of the patterned portion of the unit, and W is a maximum width of the optical pattern in micrometers, and wherein at least one of the first resin layer and the second resin layer comprises a metal misalignment Dye and At least one of the organic black dyes. The optical film of claim 1, wherein the at least one of the metal complex dye and the organic black dye is contained in the second resin in an amount of 0.01% by weight to 10% by weight. In the layer. The optical film of claim 1, wherein the at least one of the metal complex dye and the organic black dye is contained in the first resin in an amount of 0.01% by weight to 10% by weight. In the layer. The optical film of claim 1, wherein the metal complex dye or the organic black dye has a D50 average particle diameter of 100 nm or less. The optical film of claim 1, wherein the second resin layer has a light transmittance of 50% to 92% at a wavelength of 550 nm. The optical film of claim 1, wherein the metal complex dye is a black dye containing chromium, nickel, cobalt or copper. The optical film of claim 6, wherein the metal complex dye is a black dye containing chromium. The optical film of claim 1, wherein the metal complex dye is a metal azo dye. The optical film of claim 1, wherein the metal complex dye is an azo dye having a C ₆ - C ₂₀ monocyclic aromatic functional group or a polycyclic aromatic functional group. The optical film of claim 1, wherein the metal complex dye is an azo dye containing chromium and having a C ₆ - C ₂₀ monocyclic aromatic functional group or a polycyclic aromatic functional group, It has a D50 average particle diameter of 100 nm or less and a content of 0.01% by weight to 10% by weight with respect to the weight of the first resin layer. The optical film of claim 1, wherein the metal complex dye is an azo dye containing chromium and having a C ₆ - C ₂₀ monocyclic aromatic functional group or a polycyclic aromatic functional group, It has a D50 average particle diameter of 100 nm or less and a content of 0.01% by weight to 10% by weight with respect to the weight of the second resin layer. The optical film of claim 1, wherein the organic black dye comprises a first dye having a maximum absorption wavelength of from 430 nm to 450 nm, and a second absorption having a maximum absorption wavelength of from 510 nm to 530 nm. The dye and the third dye having a maximum absorption wavelength of from 590 nm to 610 nm. The optical film of claim 12, wherein each of the first dye, the second dye, and the third dye comprises an azo dye. The optical film according to claim 12, wherein the first dye is represented by the following formula 1, the second dye is represented by the following formula 2, and the third dye is represented by the following formula 3: 1> , <Formula 2> , and <Formula 3> . The optical film of claim 1, wherein the first resin layer has an adhesive property. The optical film of claim 1, wherein the optical pattern comprises a pattern having a trapezoidal shape, a rectangular shape, or a square shape in cross section. The optical film of claim 1, wherein in the second resin layer, a space between the embossed optical pattern and the immediately adjacent embossed optical pattern is defined as a first And the metal complex when the space between the virtual surface connecting the first surface of the top surface of the embossed optical pattern and the lower surface of the protective layer, which are spaced apart from each other, is defined as the second region The at least one of the dye and the organic black dye is included in both the first zone and the second zone. The optical film of claim 1, wherein in the second resin layer, a space between the embossed optical pattern and the immediately adjacent embossed optical pattern is defined as a first The metal complex when the space between the virtual surface connecting the first surface of the top surface of the embossed optical pattern and the lower surface of the protective layer, which are spaced apart from each other, is defined as the second region The at least one of the dye and the organic black dye is included in the first zone and is not included in the second zone. A polarizing plate comprising: a polarizing film; and the optical film according to any one of claims 1 to 18, wherein the optical film is formed on a light exit surface of the polarizing film. A liquid crystal display device comprising the polarizing plate according to claim 19 of the patent application.