KR101078599B1 - High luminance multifunctional polarizing sheet, rear polarizing film of liquid crystal display with them and liquid crystal display having the same - Google Patents

Abstract

The present invention relates to a high-brightness polarizing sheet in which an iodine-based or dye-based absorbing polarizing layer and a fibrous reflective polarizing layer composed of birefringent island-in-the-sea yarns are integrated.

In the integrated high brightness polarizing sheet of the present invention, a birefringent island-in-the-sea yarn having a birefringent island-in-the-sea yarn by disposing a fibrous reflective polarization layer made of birefringent island-in-the-sea yarn while maintaining high polarization efficiency by the conventional absorption type polarizing layer. The birefringent interface between the constituent sea component and the island component enhances the light condensing efficiency of incident light, thereby realizing high brightness. Accordingly, the present invention provides a polarizing film for a rear surface of a liquid crystal display panel (Liquid Crystal Display, hereinafter referred to as "LCD") combining a conventional absorbing layer polarizing film layer and a fibrous reflective polarizing layer composed of birefringent island-in-the-sea yarns. It can provide high-efficiency efficiency while localizing materials and providing finished products with price competitiveness.

Absorption polarizing layer, birefringent island-in-the-sea yarn, fibrous reflective polarizing layer, polarizing film

Description

HIGH LUMINANCE MULTIFUNCTIONAL POLARIZING SHEET, REAR POLARIZING FILM OF LIQUID CRYSTAL DISPLAY WITH THEM AND LIQUID CRYSTAL DISPLAY HAVING THE SAME}

The present invention relates to an integrated high-brightness polarizing sheet, a polarizing film for the back of the LCD panel applied thereto and a liquid crystal display having the same, more specifically, by integrating a fibrous reflective polarizing layer made of an absorption polarizing layer and a birefringent island-in-the-sea yarn, The present invention relates to a polarizing sheet in which high luminance is realized by a fibrous reflective polarizing layer while maintaining a high polarization efficiency by an absorption type polarizing layer, a polarizing film for LCD panel back applied thereto, and a liquid crystal display having the same.

As the modern industrial society develops into a high information age, the importance of the electronic display as a medium for transmitting various information is increasing day by day, and the liquid crystal display (LCD) is very important as a display device of information in place of the CRT. Occupies the position. In addition to mobile phones, car navigation systems are used for on-vehicle devices, especially monitors and large-screen TVs.

Liquid crystal display (LCD) is a display method that controls the light emitted from the backlight on-off by using the light switching function of liquid crystal molecules, but various kinds of optical films are used to realize high quality display. . As an optical film, a film group (diffusion film, prism sheet, brightness enhancement film, etc.) for effectively using a backlight, a film group (polarizing film, polarizer protective film) used for a polarizing plate, a phase difference between a liquid crystal cell and a polarizing plate is corrected. Retardation film).

According to a recent research report on display related fields, the market for optical films for backlights related to prism sheets, DBEF sheets, diffusers, and reflective films is growing day by day.

Commercially available polarizing films include absorption type or non-absorption type, and absorption type includes iodine-based polarizer or dye-based polarizer. Most of the polarizing plates currently used are PVA-iodine polarizing films having excellent optical characteristics.

PVA-iodine polarizing film is a polyvinyl alcohol (PVA) film is adsorbed iodine having a high dichroic to the PVA film in order to give the light absorbing ability of the visible light region, due to the structural characteristics of the iodine, Will have In this case, the polarizer property is to change the isotropic light into anisotropic polarization in the form of linear vibration or rotational vibration in one direction to enable selective polarization absorption.

However, PVA-iodine polarizing film has a birefringence, high light transmittance, no wavelength dependence, high heat resistance moisture resistance and high mechanical strength in order to prevent deformation of the film due to high sublimation and low durability of iodine. The film should be laminated with a protective film.

Accordingly, the PVA-dye polarizing film that appeared as an alternative to solve the durability problem due to the sublimation of iodine has polarizer properties due to the dichroism of the aligned dye itself during stretching, and even under high temperature and high humidity conditions. Since it has durability, there is little change in optical properties, and it is particularly suitable as a highly durable polarizing film for LCD which requires durability.

Another type of polarizing film is a reflective polarizing film that improves the polarization function and the brightness of the transmitted light through the rotation and secondary reflection of the reflected light after passing through the film. The reflective polarizing film is a film that uses specific polarization technology to emit specific light and continuously reflects specific light so that light can be used as much as possible without light loss.

Reflective polarizing films are manufactured by stacking layers having different refractive indices, etc., and are being used for improving luminance for maximizing light from light sources of LCDs and displays rather than polarizing films due to the lack of linearity of polarization. At this time, as a method of stacking multiple layers is applied, it is difficult to realize thinning of the film and causes a price increase.

As shown in FIG . 1 , the structure of a general liquid crystal display (LCD) is largely composed of a panel 100 and a backlight unit 200, and the polarizing film 400 located at the rear of the panel 100 will be described in more detail. 2 , the PVA protective films 420 and 430 are laminated on both sides of a polyvinyl alcohol (PVA) film 410 called a polarizer for implementing the most important polarization function in the polarizing film. In this case, a brightness enhancing film (3M DBEF sheet, 300) is inserted on the PVA protective film 420 located close to the LCD backlight 200 side, and a viewing angle compensating film on another PVA protective film 430. (Retardation plate 310) may be laminated.

Accordingly, the present inventors have made efforts to develop a polarizing film capable of reducing manufacturing costs while implementing polarization and luminance performance improvement of the conventional polarizing film. As a result, the birefringence diagram of the absorption type polarizing film including the conventional iodine-based or dye-based film The present invention was completed by integrating a fibrous reflective polarizing sheet made of yarns to produce a high brightness polarizing sheet.

An object of the present invention is to provide a high-brightness polarizing sheet in which a conventional iodine-based or dye-based absorbing polarizing layer and a fibrous reflective polarizing layer made of birefringent island-in-the-sea yarns are integrated.

Another object of the present invention is the LCD to which the integrated high brightness polarizing sheet is applied. To provide a rear panel polarizing film, and furthermore, a liquid crystal display having the same.

The present invention provides a high-brightness polarizing sheet in which a fibrous reflective polarizing layer made of birefringent island-in-the-sea yarns and an iodine-based or dye-based absorbing polarizing layer are integrated.

Polarizing sheet of the present invention can be integrated between the layers by an adhesive.

In the integrated high brightness polarizing sheet of the present invention, the diameter of the birefringent island-in-the-sea yarn is 0.3 to 50 denier, and the thickness of the fibrous reflective polarizing layer 10 made of the birefringent island-in-the-sea yarn is 10 to 500 mu m.

In the fibrous reflective polarization layer 10 made of the birefringent island-in-the-sea yarn in the integrated high-brightness polarizing sheet of the present invention, the refractive index between the sea component and the island component satisfies the following equation.

┃n'x-nx┃> 0.1 (1)

┃n'y-ny┃ <0.05 (2)

┃n'z-nz┃ <0.05 (3)

(In the above, n'x is the refractive index in the stretching direction (x-axis direction) of the island component, n'y and n'z are the refractive indices in the y and z directions, which are perpendicular to the stretching direction, and nx and ny And nz are refractive indices in the x-axis direction, y-direction, and z-direction of the sea component.)

In the birefringent island-in-the-sea yarn, any one of the sea component or island component is isotropic and the other is anisotropic, and the sea component of the island-in-the-sea yarn is polyethylene naphthalate (PEN), copolyethylene naphthalate (co-PEN), or polyethylene tere. Phthalate (PET), Polycarbonate (PC), Polycarbonate (PC) Alloy, Polystyrene (PS), Heat Resistant Polystyrene (PS), Polymethylmethacrylate (PMMA), Polybutylene Terephthalate (PBT), Polypropylene (PP), polyethylene (PE), acrylonitrile butadiene styrene (ABS), polyurethane (PU), polyimide (PI), polyvinyl chloride (PVC), styrene acrylonitrile mixture (SAN), ethylene vinyl acetate (EVA), polyamide (PA), polyacetal (POM), phenol, epoxy (EP), urea (UF), melamine (MF), unsaturated polyester (UP), silicone (SI), elastomers and cycloolefins At least one material selected from the group consisting of polymers It is made preferable.

In addition, the island component of the island-in-the-sea yarn is polyethylene naphthalate (PEN), copolyethylene naphthalate (co-PEN), polyethylene terephthalate (PET), polycarbonate (PC), polycarbonate (PC) alloy, polystyrene (PS) Heat-resistant polystyrene (PS), polymethyl methacrylate (PMMA), polybutylene terephthalate (PBT), polypropylene (PP), polyethylene (PE), acrylonitrile butadiene styrene (ABS), polyurethane (PU) , Polyimide (PI), polyvinyl chloride (PVC), styrene acrylonitrile mixture (SAN), ethylene vinyl acetate (EVA), polyamide (PA), polyacetal (POM), phenol, epoxy (EP), It is preferably made of at least one material selected from the group consisting of urea (UF), melamine (MF), unsaturated polyester (UP), silicone (SI), elastomer and cycloolefin polymer.

In the present integrated high brightness polarizing sheet, the dye-based absorption type polarizing layer is preferably any one selected from dyes or pearl dyes selected from the group consisting of azo, anthraquinone, cyandidigo, perylene and phthalone.

Accordingly, the present invention provides a polarizing film for LCD panel rear panel combining a fibrous reflective polarization layer made of birefringent island-in-the-sea yarn and a high-brightness polarizing sheet in which an iodine-based or dye-based absorbing polarizing layer is integrated.

More specifically, the PVA protective film is laminated on both sides of a polyvinyl alcohol (hereinafter referred to as 'PVA') film as a polarizer, and a fibrous reflective polarizing layer made of birefringent island-in-the-sea yarn on one side of the lamination; A protective film is sequentially laminated, and on the laminated back side, an adhesive and a release paper are sequentially laminated to provide an LCD panel rear polarizing film.

In the polarizing film for LCD panel rear surface of the present invention, the PVA protective film is preferably a hydrophobic transparent resin film containing a triacetyl cellulose film or polyethylene terephthalate.

Thus, in the integrated polarizing sheet of the present invention, since the sea component and island component composed of islands-in-the-sea yarns in the fibrous reflective polarization layer satisfy a specific refractive index, high luminance is realized.

In addition, the diameter of the birefringent island-in-the-sea yarn in the integrated polarizing sheet is 0.3 to 50 denier, and the thickness of the fibrous reflective polarizing layer made of the birefringent island-in-the-sea yarn is 10 to 500 µm.

Furthermore, the present invention provides a liquid crystal display consisting of a panel and a backlight unit provided with the polarizing film for the LCD panel back.

The present invention provides a polarizing sheet in which a fibrous reflective polarizing layer made of a birefringent island-in-the-sea yarn is integrated into a conventional iodine-based or dye-based absorbing polarizing layer, thereby maintaining the high polarization efficiency by the conventional absorbing polarizing layer, The birefringent interface between islands and islands and the birefringent interface between sea islands and island components constituting the birefringent island yarns enhance the condensing efficiency of incident light incident at an invalid angle as well as high brightness by increasing the incident light incident at an invalid angle. Implement

Therefore, the integrated high brightness polarizing sheet of the present invention can replace the conventional brightness enhancement film (DBEF), it is possible to localize the material, it is possible to provide a polarizing film for LCD panel rear with a cost competitiveness.

Accordingly, the present invention can expect high polarization and high luminance efficiency of the liquid crystal display consisting of a panel and a backlight unit provided with a polarizing film for the LCD panel back.

Hereinafter, the present invention will be described in detail.

The present invention provides a high-brightness polarizing sheet in which a fibrous reflective polarization layer 10 made of birefringent island-in-the-sea yarns and an iodine-based or dye-based absorbing polarizing layer 30 are integrated.

In the polarizing sheet 1 of the present invention, the integration means that the absorbing polarizing layer 30 and the fibrous reflective polarizing layer 10 may be integrated by the interlayer bonding means, and the bonding means may be the absorbing polarizing layer ( 30) and directly applied between the fibrous reflective polarization layer 10, or if a protective film or a release film is laminated between the layers as necessary, it may be applied for the purpose of adhesion between the multi-layer.

Figure 3 is a schematic diagram of an integrated polarizing sheet which is a preferred embodiment of the present invention, on the fibrous reflective polarization layer 10 made of birefringent islands (12), the adhesive layer 20 and the iodine-based or dye-based absorption type The polarizing layer 30 is sequentially laminated and integrated.

In the integrated polarizing sheet 1 of the present invention, the fibrous reflective polarization layer 10 made of the birefringent island-in-the-sea yarn 12 is a fiber layer in which the birefringent island-in-the-sea yarn or the birefringent island-in-the-sea yarn is partially dispersed and woven.

4 is The polarizing sheet of FIG. 3, which is a preferred embodiment of the present invention, illustrates the high luminance principle of the polarizing sheet 1 in which the absorbing polarizing layer 30 and the fibrous reflective polarizing layer 10 are integrated. The refractive index of the island component in the polarizing layer 10 in the stretching direction (x-axis direction) is n'x, and the refractive indices in the y and z directions, which are perpendicular to the stretching direction, are n'y and n'z, respectively. When the refractive indexes in the x-axis direction, the y-direction, and the z-direction of the sea component are nx, ny, and nz, respectively, the difference between the x-axis refractive index of the island component and the x-axis refractive index of the sea component is large, and is perpendicular to the stretching direction. If the refractive indices n'y and n'z in the y and z directions of the island component in the phosphorus direction are the same as the refractive indices in the y and z directions of the sea component (n'y = ny and n'z = nz), the polarizing layer The luminance efficiency is increased by using the polarization effect of the birefringent interface between the sea component and the island component.

In the fibrous reflective polarization layer 10 composed of the birefringent island-in-the-sea yarns 12, the refractive index between the sea component and the island component satisfies the following equation.

┃n'x-nx┃> 0.1 (1)

┃n'y-ny┃ <0.05 (2)

┃n'z-nz┃ <0.05 (3)

In the above, n'x is the refractive index in the stretching direction (x-axis direction) of the island component, n'y and n'z are the refractive indices in the y and z directions, which are perpendicular to the stretching direction, and nx, ny and nz is the refractive index of the x-axis direction, the y direction, and the z direction of a sea component.

According to the above principle, the light transmitted to the panel first reaches the fibrous reflective polarization layer 10 of the polarizing sheet 1, and passes only the polarization (P polarization) portion perpendicular to the stretching direction, and the polarization of the remaining stretching direction. S polarization is reflected downward. In this process, the S-polarized light is re-reflected at the bottom, and the polarized light is changed and rises upward. Among the changed polarized light, P-polarized light passes and the remaining S-polarized light is recycled, thereby increasing luminance. At this time, the P-polarized light passes through the absorption type polarizing layer 30 to realize a polarization efficiency of 99.99% or more.

Accordingly, the polarizing sheet 1 of the present invention integrates the fibrous reflective polarization layer 10 made of the iodine-based or dye-based absorption type polarizing layer 30 and the birefringent island-in-the-sea yarn 12, thereby absorbing the conventional absorption type polarizing layer. By means of the birefringent interface between the birefringent islands and the birefringent interface between the sea component and the island component constituting the birefringent islands, and not only the incident light incident at an effective angle The brightness can be dramatically improved by increasing the light condensing efficiency of incident light incident at an angle. Thus, the integrated high-brightness polarizing sheet 1 of the present invention can realize a high brightness or higher even if not laminated in a multi-layer like the conventional reflective polarizing film.

In the birefringent island-in-the-sea yarn 12 of the present invention, either the sea component or the island component should be isotropic and the other should be anisotropic. That is, since the optical properties of the sea component or island component are different in the birefringent island-in-the-sea yarn 12, and the birefringence interface is formed inside the island-in-the-sea yarn, the brightness enhancement efficiency is significantly increased in comparison with the other case.

More specifically, in the birefringent island-in-the-sea yarn 12 of the present invention, the sea component has isotropy, and the island component has anisotropy, so that the light reaching the panel constitutes the boundary between the sea component and the island component that constitute the interior of the island-in-the-sea yarn. Due to birefringence, P-polarized light passes through the polarizing sheet, and S-polarized light continuously recycles the path of increasing luminance while recycling.

At this time, in the integrated polarizing sheet 1 of the present invention, the birefringent island-in-the-sea yarn 12 in the fibrous reflective polarization layer 10 uses a material that is optically birefringent and has excellent light transmittance, and twists several tens of strands. It can be prepared and used as a composite fiber.

In the birefringent island-in-the-sea yarn 12 of the present invention, it is preferable to use a material having the same sea component and island component, and examples thereof include polyethylene naphthalate (PEN), copolyethylene naphthalate (co-PEN), and polyethylene terephthalate. (PET), polycarbonate (PC), polycarbonate (PC) alloy, polystyrene (PS), heat-resistant polystyrene (PS), polymethyl methacrylate (PMMA), polybutylene terephthalate (PBT), polypropylene ( PP), polyethylene (PE), acrylonitrile butadiene styrene (ABS), polyurethane (PU), polyimide (PI), polyvinyl chloride (PVC), styrene acrylonitrile mixture (SAN), ethylene vinyl acetate ( EVA), polyamide (PA), polyacetal (POM), phenol, epoxy (EP), urea (UF), melamine (MF), unsaturated polyester (UP), silicone (SI), elastomer and cycloolefin polymer Use at least one selected from the group consisting of.

That is, the birefringent island-in-the-sea yarn 12 of the present invention uses the same material of sea component and island component, but can be used as long as it is a combination of resins having different optical properties. For example, the sea component of the island-in-the-sea yarn may use isotropic co-PEN, and the island component may use PEN having birefringence, but is not limited thereto.

In this case, the refractive index of the isotropic sea component is 1.4 to 2.0, and in some cases, may match the refractive index of the transparent substrate 11 in the fibrous reflective polarization layer 10.

The shape of the cross-section of the birefringent island-in-the-sea yarn 12 of the present invention is not particularly limited to a circle, an ellipse, a polygon, and the like, and may have various cross-sectional shapes. In addition, the cross section of the island component among the islands and seams is also not limited to the shape of the shape can also have a heteromorphic cross section, such as round, oval, polygon, etc., the shape, size, number and arrangement of the island component is effectively adjusted according to the purpose Can be used. However, the birefringent island-in-the-sea yarn 12 of the present invention should satisfy the area ratio of the sea component and the island component of 2: 8 to 8: 2 based on the cross section.

In the integrated polarizing sheet 1 of the present invention, the birefringent island-in-the-sea yarn 12 constituting the fibrous reflective polarization layer 10 has a thickness of 0.3 to 50 denier, and the fiber composed of the birefringent island-in-the-sea yarn 12. 10-500 micrometers is preferable and, as for the thickness of the type reflective polarizing layer 10, More preferably, it is 10-300 micrometers. At this time, when the thickness of the polarizing layer is less than 10 μm, the brightness enhancement effect due to the birefringent island-in-the-sea yarn is insufficient, and when the thickness of the polarization layer exceeds 500 μm, the brightness enhancement effect does not increase any more and is saturated. However, it is not preferable because it acts as a cost increase factor.

The transparent base material 11 used in the integrated polarizing sheet 1 of the present invention may be used without particular limitation as long as it is a transparent resin that can be used for optical purposes, and examples thereof include polymethyl methacrylate (PMMA) and polystyrene (PS). ), Polyethylene terephthalate (PET), random copolymer resin of styrene and methyl methacrylate (MS resin) or polycarbonate (PC) can be used.

As described above, in the integrated high-brightness polarizing sheet 1 of the present invention, the fibrous reflective polarization layer 10 emits specific light, and on the other hand, continuously reflects specific light to use the light as much as possible without the loss of light. High brightness is achieved by making it possible. In particular, since the fibrous reflective polarizing layer is composed of a birefringent island-in-the-sea fibrous type, the manufacturing cost is lower than that of the conventional multilayer thin film reflective polarizing layer, and thus, price competitiveness can be achieved.

In the integrated high brightness polarizing sheet 1 of the present invention, the absorption type polarizing layer 30 can be used without particular limitation as long as it is conventionally used, and typically includes an iodine-based or dye-based absorption type polarizing layer. As the dye-based, any one selected from a dye selected from the group consisting of azo-based, anthraquinone-based, cyiodigo-based, perylene-based and phthalone-based or pearl dyes can be used.

In addition, the integration of the present invention refers to the integration by the adhesive means, preferably an integration method by the optical adhesive without optical damage, wherein the thickness of the adhesive layer 20 is not particularly limited, but 2 to 10㎛ is preferred. Do.

The present invention provides a polarizing film for an LCD panel back surface combining a fibrous reflective polarizing layer made of birefringent island-in-the-sea yarn and a polarizing sheet in which an iodine-based or dye-based absorbing polarizing layer is integrated.

More specifically, the PVA protective films 42 and 43 are laminated on both surfaces of a polyvinyl alcohol (hereinafter, referred to as 'PVA') film 41 which is a polarizer, and the birefringent islands are formed on one surface of the lamination. The fibrous reflective polarization layer 10 and the protective film 44 made of yarn are sequentially stacked, and on the back side of the laminate, an adhesive 45 and a release paper 46 are sequentially stacked to provide a polarizing film for the back of the LCD panel . 5 ]. In FIG. 5, a phase difference or viewing angle compensation film may be stacked between the PVA protective film 43 and the pressure-sensitive adhesive 45, depending on whether the phase difference or viewing angle compensation is required.

In the LCD panel rear polarizing film 40 of the present invention, the PVA film 41 and the PVA protective films 42 and 43 are absorbing polarizing film layers, wherein the PVA protective film is triacetyl cellulose, It can be selected from hydrophobic transparent resin film including 'TAC') film or polyethylene terephthalate (hereinafter referred to as 'PET').

In the LCD panel rear polarizing film 40 of the present invention, the thickness of the fibrous reflective polarization layer 10 is preferably 10 to 500 µm.

At this time, the polarizing sheet 1 in the fibrous reflective polarization layer 10 made of birefringent island-in-the-sea yarns, the refractive index between the sea component and the island component satisfies the following equation.

┃n'x-nx┃> 0.1 (1)

┃n'y-ny┃ <0.05 (2)

┃n'z-nz┃ <0.05 (3)

In the above, n'x is the refractive index in the stretching direction (x-axis direction) of the island component, n'y and n'z are the refractive indices in the y and z directions, which are perpendicular to the stretching direction, and nx, ny and nz is the refractive index of the x-axis direction, the y direction, and the z direction of a sea component.

When the above refractive index conditions are satisfied, not only incident light incident at an effective angle due to the birefringent interface between the birefringent island-in-the-sea yarns 12 and the birefringent interface between sea components and island components constituting the birefringent island-in-the-sea yarns is not effective. The brightness can be dramatically improved by increasing the light condensing efficiency of incident light incident at an angle.

Accordingly, the LCD panel rear polarizing film 40 of the present invention is a combination of the absorption type polarizing layer consisting of the PVA film 41 and PVA protective films 42, 43 and the fibrous reflective polarization layer 10, Since high brightness can be realized from the fibrous reflective polarization layer 10 while maintaining high polarization efficiency from the absorbing polarizing film layer, a conventional brightness absorbing polarizing film and an expensive luminance enhancing film (3M company's DBEF film) Can be used in place of a combination of. In terms of manufacturing cost, the fibrous reflective polarizing layer is cheaper than the conventional multilayer thin film reflective polarizing layer, and the manufacturing cost can be reduced by simplifying the assembly process of the optical component through the integration of the existing polarizing film and the luminance enhancing film.

Accordingly, the present invention combining the conventional absorbing polarizing film layer and the fibrous reflective polarizing layer made of birefringent island-in-the-sea yarns can provide a final product having a cost competitiveness as well as localizing the material of the LCD panel rear polarizing film 40. .

Furthermore, the present invention can be expected to improve the performance of the liquid crystal display consisting of the panel 100 and the backlight unit 200 provided with the polarizing film 40 for the rear LCD panel.

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

The following examples are merely illustrative of the present invention, but the scope of the present invention is not limited to the following examples.

&Lt; Example 1 >

Step 1: preparing absorbing polarizing layer

0.2 parts by weight of anthraquinone dichroic dye (Disperse red 60) was mixed with respect to 100 parts by weight of polyethylene terephthalate, followed by extrusion at 270 ° C. to prepare a 200 μm thick film, which was stretched 5 times at 100 ° C. A polarizing film was prepared.

Step 2: preparing a fibrous reflective polarizer layer

Unstretched with anisotropic PEN (nx = 1.88, ny = 1.57, nz = 1.57) as a drawing part inside the filler of isotropic Co-PEN (nx = 1.57, ny = 1.57, nz = 1.57) After the island-in-the-sea yarn was spun under the condition of a spinning temperature of 305 ° C. and a spinning speed of 1500 M / min, a stretched island-in-the-sea yarn of 50d / 24F was obtained by three times stretching.

Isotropic Co-PEN is used as a warp, using four fibers (50d / 24F × 4) of the island-in-the-sea yarn manufactured above as a warp yarn.

The fabric was woven into the fabric using the weft yarn . Co-PEN resin was added to a twin-screw extruder to melt extrusion, and a fibrous reflective polarizing film having a thickness of 250 μm was prepared after cooling by laminating a fabric made of the island-in-the-sea yarn to a resin extruded through a T-die. .

Step 3: manufacture the integrated polarizing sheet

After applying the UV curable adhesive on one surface of the fibrous reflective polarizing film prepared in Step 2, the absorbing polarizing film prepared in Step 1 was placed thereon to bond the interlayers to form the integrated polarizing film 40 for the back of the LCD panel. Prepared.

After assembling the panel on the 32 "direct backlight unit, the brightness was measured using Topcon's BM-7 measuring device. When the conventional brightness enhancing film (3M DBEF film) was inserted into the LCD panel back, While showing a 40% improvement, the result of attaching a polarizing film in which the absorbing polarizing layer of the present invention and the fibrous reflective polarizing layer made of birefringent island-in-the-sea yarns was attached, confirmed the result of improving the luminance of 45 to 50%.

As described above, the present invention

First, by providing a polarizing sheet incorporating a fibrous reflective polarizing layer made of a birefringent island-in-the-sea yarn in a conventional iodine-based or dye-based absorbing polarizing layer, while maintaining a high polarization efficiency by a conventional absorbing polarizing layer, The birefringent interface between the sand and the birefringent interface between the sea component and the island component constituting the birefringent island-in-the-sea yarn can enhance the light condensing efficiency of the incident light, thereby realizing high brightness. Thus, an integrated high brightness polarizing sheet that satisfies high polarization and high brightness was provided.

Second, by applying the integrated high-brightness polarizing sheet to the polarizing film for LCD panel back, while maintaining the high polarization from the conventional absorption type polarizing layer, the brightness (45-50%) than the conventional brightness enhancement film (40% brightness) equipped with Is improved, and can be replaced with expensive commercial film products, it is possible to provide a product with a competitive price.

Third, a liquid crystal display device including a panel and a backlight unit having a polarizing film for LCD panel rear surface of the present invention can be expected to improve the performance of high polarization and high brightness.

While the invention has been shown and described with reference to certain exemplary embodiments thereof, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined by the appended claims.

1 is a schematic diagram of the structure of a general liquid crystal display (LCD),

2 is a cross-sectional view of a conventional polarizing sheet,

3 is a schematic diagram of an integrated polarizing sheet which is a preferred embodiment of the present invention;

4 is It illustrates the high brightness principle of the integrated polarizing sheet of the present invention,

Figure 5 shows an example of a preferred structure of the polarizing film for the back panel of the LCD panel to which the integrated polarizing sheet of the present invention is applied.

<Brief Description of Drawings>

1: Integrated Polarizing Sheet 10: Fibrous Reflective Polarizing Layer

11: Base sheet 12: birefringent sea island

20: adhesive layer 30: absorbing polarizing layer

41: PVA film 42, 43: PVA protective film

44: protective film 45: adhesive

46: release paper 100: panel

40: polarizing film 50, 51 for the back panel

60: panel polarizing film 70: pattern material

71: alignment layer 72: ITO

73: liquid crystal 74: color PR

75: overcoat 200: backlight unit

210: reflective sheet 220: light source

230: diffusion plate 240: diffusion sheet

250: prism sheet 300: brightness enhancement film (DBEF film)

310: viewing angle compensation film 400: conventional polarizing film

410: PVA film 420: first PVA protective film

430: second PVA protective film

Claims (15)

On the fibrous reflective polarizing layer made of birefringent islands, Adhesive layer and Iodine- or dye-based absorption type polarizing layer is a structure in which the stacking sequentially, In the fibrous reflective polarization layer made of the birefringent island-in-the-sea yarn, the difference between the refractive index of the island component (x 'axis direction) and the refractive index of the sea component (x axis direction) satisfies Equation (1), The refractive indices n'y and n'z in the y and z directions of the island component perpendicular to the stretching direction are the same as the refractive indices ny and nz in the y and z directions of the sea component (n'y = ny and n'z). = nz) high brightness polarizing sheet characterized by: ┃n'x-nx┃> 0.1 (1) In the above, n'x is the refractive index of the island component in the x-axis direction, and nx is the refractive index of the sea component in the x-axis direction. delete The high brightness polarizing sheet according to claim 1, wherein the birefringent island-in-the-sea yarn has a diameter of 0.3 to 50 denier. The high brightness polarizing sheet according to claim 1, wherein the fibrous reflective polarizing layer made of birefringent island-in-the-sea yarns has a thickness of 10 to 500 µm. delete The high brightness polarizing sheet according to claim 1, wherein any of the birefringent island-in-the-sea yarns is isotropic, and the other is anisotropic. The sea component of the island-in-the-sea yarn of claim 6 is polyethylene naphthalate (PEN), copolyethylene naphthalate (co-PEN), polyethylene terephthalate (PET), polycarbonate (PC), polycarbonate (PC) alloy, polystyrene (PS), heat-resistant polystyrene (PS), polymethyl methacrylate (PMMA), polybutylene terephthalate (PBT), polypropylene (PP), polyethylene (PE), acrylonitrile butadiene styrene (ABS), polyurethane (PU), polyimide (PI), polyvinyl chloride (PVC), styrene acrylonitrile mixture (SAN), ethylene vinyl acetate (EVA), polyamide (PA), polyacetal (POM), phenol, epoxy ( EP), urea (UF), melamine (MF), unsaturated polyester (UP), silicone (SI), elastomer and cycloolefin polymer, characterized in that the high brightness polarizing sheet comprising at least one material selected from the group consisting of . According to claim 6, wherein the island component of the island-in-the-sea yarn is polyethylene naphthalate (PEN), copolyethylene naphthalate (co-PEN), polyethylene terephthalate (PET), polycarbonate (PC), polycarbonate (PC) alloy, polystyrene (PS), heat-resistant polystyrene (PS), polymethyl methacrylate (PMMA), polybutylene terephthalate (PBT), polypropylene (PP), polyethylene (PE), acrylonitrile butadiene styrene (ABS), polyurethane (PU), polyimide (PI), polyvinyl chloride (PVC), styrene acrylonitrile mixture (SAN), ethylene vinyl acetate (EVA), polyamide (PA), polyacetal (POM), phenol, epoxy ( EP), urea (UF), melamine (MF), unsaturated polyester (UP), silicone (SI), elastomer and cycloolefin polymer, characterized in that the high-brightness polarizing sheet comprising at least one material selected from the group consisting of . delete On both sides of the polyvinyl alcohol (PVA) film which is a polarizer, PVA protective films are laminated, respectively, one side of the lamination, the fibrous reflective polarizing layer and the protective film made of birefringent island-in-the-sea yarn is sequentially laminated, and the adhesive and release paper is sequentially laminated on the back of the lamination, In the fibrous reflective polarization layer made of the birefringent island-in-the-sea yarn, the difference between the refractive index of the island component (x 'axis direction) and the refractive index of the sea component (x axis direction) satisfies Equation (1), The refractive indices n'y and n'z in the y and z directions of the island component perpendicular to the stretching direction are the same as the refractive indices ny and nz in the y and z directions of the sea component (n'y = ny and n'z). = nz) polarizing film for the back of the LCD panel: ┃n'x-nx┃> 0.1 (1) In the above, n'x is the refractive index of the island component in the x-axis direction, and nx is the refractive index of the sea component in the x-axis direction. The polarizing film for back panel of claim 10, wherein the PVA protective film is a hydrophobic transparent resin film containing a triacetyl cellulose film or polyethylene terephthalate. The polarizing film of claim 10, wherein a diameter of the birefringent island-in-the-sea yarn in the fibrous reflective polarization layer is 0.3 to 50 denier. 11. The LCD panel back polarizing film according to claim 10, wherein a thickness of the fibrous reflective polarizing layer made of birefringent islands in the fibrous reflective polarizing layer is 10 to 500 mu m. delete delete

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