KR101109134B1 - Manufacturing method of light modulated film - Google Patents

Abstract

The present invention relates to a method of manufacturing an optical modulation film, and more particularly, to include a fabric containing a birefringent island-in-the-sea yarn having two or more spinning cores between the substrates during the lamination of the substrate, significantly lowering the production cost while reducing the brightness It provides a method for producing a light modulated film enhanced by.

Description

Manufacturing method of light modulated film

The present invention relates to a method of manufacturing an optical modulation film, and more particularly, to include a fabric containing a birefringent island-in-the-sea yarn having two or more spinning cores between the substrates during the lamination of the substrate, significantly lowering the production cost while reducing the brightness It is to provide a method for producing a light modulated film enhanced by.

Flat panel display technology is mainly made up of liquid crystal display (LCD), projection display, and plasma display (PDP), which have already secured market in TV, and related technologies such as field emission display (FED) and electroluminescent display (ELD) With the improvement of the market, it is expected to occupy the field according to each characteristic. LC displays are currently expanding their range of use, including notebooks, personal computer monitors, liquid crystal TVs, automobiles, and airplanes, accounting for about 80% of the flat panel market. have.

Conventional LC displays place liquid crystals and electrode matrices between a pair of light absorbing optical films. In an LC display, the liquid crystal portion has an optical state that is changed accordingly by moving the liquid crystal portion by an electric field generated by applying a voltage to two electrodes. This process displays an image of a 'pixel' carrying information using polarization in a specific direction. For this reason, LC displays include front and back optical films that induce polarization.

  The liquid crystal display of such an LC display is not necessarily a high utilization efficiency of light emitted from the backlight. This is because at least 50% of the light emitted from the backlight is absorbed by the rear optical film. Thus, in order to increase the utilization efficiency of the backlight light in the liquid crystal display device, an optical modulation film is provided between the optical cavity and the liquid crystal assembly.

  1 is a view showing the optical principle of a conventional optical modulation film.

  Specifically, P-polarized light from the optical cavity to the liquid crystal assembly passes through the optical modulation film to the liquid crystal assembly, and S-polarized light is reflected from the optical modulation film to the optical cavity and then polarized light on the diffuse reflection surface of the optical cavity. The direction is reflected in a randomized state and is transmitted back to the optical modulation film so that S-polarized light is converted into P-polarized light that can pass through the polarizer of the liquid crystal assembly, and then passed through the optical modulation film to be transferred to the liquid crystal assembly.

The selective reflection of S-polarized light and the transmission of P-polarized light with respect to the incident light of the optical modulation film have refractive indexes between the optical layers in a state where an optical layer on a plate having anisotropic refractive index and an optical layer on a plate having an isotropic refractive index are alternately stacked. It is made by the optical thickness setting of each optical layer and the refractive index change of the optical layer according to the difference and the stretching process of the stacked optical layers.

  That is, the light incident on the optical modulation film repeats the reflection of S-polarized light and the transmission of P-polarized light through each optical layer, and eventually only the P-polarized light of the incident polarization is transmitted to the liquid crystal assembly. On the other hand, the reflected S-polarized light is reflected in a state in which the polarization state is randomized at the diffuse reflection surface of the optical cavity and is transmitted to the light modulation film again. As a result, power loss can be reduced together with the loss of light generated from the light source.

  By the way, such a conventional optical modulation film is laminated with anisotropic optical layer and anisotropic optical layer on a flat plate having different refractive indices, and stretched to obtain optical thickness and refractive index between each optical layer that can be optimized for selective reflection and transmission of incident polarization. Since it is manufactured to have, there is a problem that the manufacturing process of the light modulation film is complicated. In particular, since each optical layer of the optical modulation film has a flat plate structure, the P-polarized light and the S-polarized light must be separated to correspond to the wide range of incident angles of the incident polarization. There was a growing problem. In addition, due to the structure in which the number of laminated layers of the optical layer is excessively formed, there is a problem that the optical performance decrease due to light loss.

Accordingly, a technique for overcoming the problems of the laminated optical modulator film by inserting birefringent fibers into the substrate has been disclosed. In this case, since the general birefringent fibers are not manufactured in a lamination type, the production cost is low and the production is easy, but there is a problem that it is difficult to be applied to an industrial site in place of the above-described lamination type optical modulation film because the effect of brightness enhancement is insignificant. Was found.

The present invention has been made to solve the above-described problem, the first problem to be solved by the present invention is a fabric comprising a birefringent island-in-the-sea yarn whose structure is changed to maximize the light modulation effect by preventing the aggregation of the island portion It is to provide a method of manufacturing an optical modulation film comprising the step of laminating the substrate between the substrate.

The second problem to be solved by the present invention is to provide a method for producing a birefringent island-in-the-sea yarn having color development when used in fabrics while being mounted on the optical modulator film of the present invention to prevent the aggregation of the island portion.

The present invention to achieve the first object,

A method of manufacturing an optical modulating film comprising placing a fabric between substrates and laminating the substrate, wherein the fabric has a birefringent island-in-the-sea yarn having a portion arranged around two or more spinning cores to form a partitioned group. In the method of manufacturing a light modulating film comprising a weft or warp, the fabric provides a light modulated film comprising a birefringent islands weft or warp yarns in which the island portion is arranged around two or more spinning cores to form a partitioned group. do.

According to a preferred embodiment of the present invention, the lamination step may be performed in a vacuum hot press, more preferably the lamination step may be performed at a vacuum degree of 1 to 500 torr.

According to another preferred embodiment of the present invention, one of the weft yarn and the warp yarn is the birefringent island-in-the-sea yarn, the other may be isotropic fibers.

According to another preferred embodiment of the present invention, the melting start temperature of the island portion of the birefringent island-in-the-sea yarn may be higher than the melting temperature of the sea portion of the isotropic fibers and the birefringent island-in-the-sea yarn, more preferably the birefringent islands The melting start temperature of the island portion of the yarn may be 30 ° C. or more higher than the melting temperature of the sea portion of the isotropic fibers and the birefringent island-in-the-sea yarn.

According to another preferred embodiment of the present invention, the weft yarn or warp yarn may be formed by gathering 1 ~ 200 strands.

According to another preferred embodiment of the present invention, the spinning peripheral core is 3 to 20, more preferably the spinning peripheral core may be 6 to 10.

According to another preferred embodiment of the present invention, 10 to 300 islands may be arranged with respect to the one radiation reference core or one radiation peripheral core.

According to still another preferred embodiment of the present invention, the total number of the conductive parts may be 50 to 1500, more preferably, the total number of the conductive parts may be 500 to 1500, and most preferably, the total conductive parts The number of may be 1000 to 1500.

According to another preferred embodiment of the present invention, the longitudinal cross-sectional shape of the islands grouped around the radiation core may be aligned in a circle or polygon, in which case the islands grouped around the radiation core. The cross-sectional shape in the longitudinal direction may be identical or different.

According to another preferred embodiment of the present invention, the spinning core may be arranged based on the center of the island-in-the-sea yarn, and more preferably, the spinning core may not be formed in the center of the island-in-the-sea yarn.

According to another preferred embodiment of the present invention, the number of the spinning core may be 3 to 20, more preferably 6 to 10.

According to another preferred embodiment of the present invention, the single yarn fineness of the island-in-the-sea yarn may be 0.5 to 30 denier, and the single yarn fineness of the island portion of the island-in-the-sea yarn may be 0.0001 to 1.0 denier.

According to another preferred embodiment of the present invention, a birefringent interface may be formed at the boundary between the island portion and the sea portion of the birefringent island-in-the-sea yarn, and more preferably, the island portion is anisotropic and the sea portion may be isotropic.

According to another preferred embodiment of the present invention, the island portion 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), It may be one or more of phenol, epoxy (EP), urea (UF), melanin (MF), unsaturated polyester (UP), silicone (SI), elastomer and cycloolefin polymer.

According to another preferred embodiment of the present invention, the sea portion 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), It may be one or more of phenol, epoxy (EP), urea (UF), melanin (MF), unsaturated polyester (UP), silicone (SI), elastomer and cycloolefin polymer.

According to another preferred embodiment of the invention, the substrate may be isotropic.

According to another preferred embodiment of the present invention, the refractive index of the substrate and the birefringent island-in-the-sea yarn may have a difference in refractive index of 0.05 or less in two axial directions and a difference in refractive index in the other one axial direction of 0.1 or more.

According to still another preferred embodiment of the present invention, the refractive index of the substrate in the x-axis direction is nX1, the y-axis refractive index is nY1 and the z-axis refractive index is nZ1, the refractive index of the birefringent island-in-the-sea yarn is nX2, nY2 and nZ2 In this case, at least one of the X, Y, Z-axis refractive indices of the substrate and the birefringent island-in-the-sea yarn may coincide, and the refractive index of the birefringent island-in-the-sea yarn may be nX2> nY2 = nZ2.

According to another preferred embodiment of the present invention, the refractive index of the sea portion and the island portion of the birefringent island-in-the-sea yarn has a difference in refractive index of 0.05 or less in two axial directions and a difference in refractive index of the other one axial direction of 0.1 or more. Can be.

According to still another preferred embodiment of the present invention, the refractive index in the x-axis direction in the longitudinal direction of the island portion of the birefringent island-in-the-sea yarn is nX3, the refractive index in the y-axis direction is nY3 and the refractive index in the z-axis direction is nZ3, When the refractive index in the x-axis direction is nX4, the refractive index in the y-axis direction is nY4, and the refractive index in the z-axis direction is nZ4, at least one of the X, Y, and Z-axis refractive indices of the birefringent island-in-the-sea yarn may coincide. The absolute value of the difference between the refractive indices of nX3 and nX4 may be 0.05 or more.

According to another preferred embodiment of the present invention, the refractive index of the sea portion of the island-in-the-sea yarn may be the same as the refractive index of the substrate.

According to another preferred embodiment of the present invention, the area ratio of the sea portion and the island portion based on the cross-section of the birefringent island-in-the-sea yarn may be 2: 8 ~ 8: 2:

According to another preferred embodiment of the present invention, the birefringent island-in-the-sea yarn may be used to extend in the longitudinal direction.

According to another preferred embodiment of the present invention, the backlight may be a CCFL or an LED.

According to another preferred embodiment of the present invention, the birefringent island-in-the-sea yarns are arranged around two or more spinning cores to form a partitioned group, but the maximum value of the center distance between adjacent islands within the same group is different from each other. It may be less than the maximum value of the center distance between adjacent islands between neighboring groups.

According to another preferred embodiment of the present invention, the light modulating film may have a structured surface.

In addition, the present invention provides a method for producing a birefringent islands, which can be applied to the optical modulation film of the present invention, in order to achieve the second object, preferably birefringent islands comprising a plurality of islands and sea portion surrounding them In the yarns, the islands are arranged about two or more spinning cores to form partitioned groups.

According to a preferred embodiment of the present invention, the birefringent island-in-the-sea yarns are arranged around two or more radiating cores to form a partitioned group, but the maximum value of the center distance between adjacent islands within the same group is adjacent to each other. It may be less than the maximum value of the center distance between adjacent island parts between groups.

According to another preferred embodiment of the present invention, the radiation core may be a single radiation reference core in the center of the birefringent islands and the plurality of radiation peripheral cores may be arranged around it.

According to another preferred embodiment of the present invention, the separation distance between the radiation reference core and the plurality of radiation peripheral cores may be substantially the same or different.

According to another preferred embodiment of the present invention, the radial peripheral core may be 6 to 10.

According to another preferred embodiment of the present invention, 10 to 300 islands may be arranged with respect to the one radiation reference core or one radiation peripheral core, and the total number of islands may be 500 to 1500.

According to another preferred embodiment of the present invention, the number of the spinning core may be 6 to 10. The single yarn fineness of the birefringent island-in-the-sea yarn may be 0.5 to 30 denier.

According to another preferred embodiment of the present invention, a birefringent interface may be formed at the boundary between the island portion and the sea portion of the birefringent islands, wherein the island portion is anisotropic and the sea portion may be isotropic.

According to another preferred embodiment of the present invention, the refractive index of the island portion and the sea portion of the birefringent island-in-the-sea yarn has a difference in refractive index of 0.05 or less in two axial directions and a difference in refractive index of the other one axial direction of 0.1 or more. Can be.

According to another preferred embodiment of the present invention, the melting start temperature of the island portion of the birefringent island-in-the-sea yarn may be 30 ° C. or more higher than the melting temperature of the sea portion.

The terms used herein are briefly described.

Unless otherwise stated, the term 'spinning core' refers to the point where the island parts in the cross section are grouped and arranged around a certain point inside the island (when partitioned) when cutting the island in the longitudinal direction. It means.

The term 'radiation reference core' refers to a radiation core which is a center when a plurality of radiation cores exist and the other radiation cores are arranged around one radiation core, and the 'radiation peripheral core' refers to one radiation core. It means the remaining spinning core to be arranged.

The term “part of islands formed to form a grouped group” means that islands of islands in the island are divided and arranged in a uniform shape with respect to one spinning core. In the case of two, the islands are arranged in a uniform shape around each spinning core so that the islands are divided into two groups within the islands.

The term "partitioned group" means not forming a group through the arrangement of the shape of the drawing part, but forming the group by the difference in the distance between the drawing parts.

'Fiber has birefringence' means that when light is irradiated on a fiber having a different refractive index according to the direction, the light incident on the polymer is refracted by two lights having different directions.

'Isotropic' means that when light passes through an object, the refractive index is constant regardless of the direction.

'Anisotropy' means that the optical properties of an object are different depending on the direction of light. Anisotropic objects have birefringence and correspond to isotropy.

'Light modulation' means that the irradiated light is reflected, refracted, scattered, or the intensity of the light, the period of the wave, or the nature of the light is changed.

The 'melting start temperature' refers to the temperature at which the melting of a polymer begins, and the 'melting temperature' refers to the temperature at which melting occurs most rapidly. Therefore, when the melting temperature of a polymer is observed by DSC, if the end point of the endothermic peak due to melting is the melting start temperature, the temperature corresponding to the vertex of the endothermic peak is the melting temperature.

'Photochromic fiber' refers to a fiber whose color is expressed by the interference of light due to the structural / optical design of the fiber, rather than being colored by the physical / chemical combination of a material having a color such as a dye or a pigment. Means.

Since the optical modulation film manufactured by the method of manufacturing the optical modulation film according to the present invention includes birefringent islands in which island portions are grouped and divided around two or more radiation cores, an optical modulation interface is formed at an interface between the island portion and the sea portion. It can be formed to maximize the light modulation effect compared to the conventional birefringent fibers. In particular, the birefringent island-in-the-sea yarn manufactured by the method of manufacturing the birefringent island-in-the-sea yarn of the present invention does not generate agglomeration (conjugation phenomenon) of the island portion even at the center of the island-in-the-sea yarn even when the number of island portions is 500 or more. As a result, the area of the light modulation interface can be maximized as compared with the conventional islands-in-the-sea yarn having one spinning core, so that the light modulation effect is significantly increased. Therefore, the brightness is remarkably improved as compared with the case of using a conventional birefringent island-in-the-sea yarn having only one birefringent fiber or one spinning core inside the sheet.

In addition, since the lamination process is performed in a vacuum hot press, it is very useful for minimizing pores and preventing curling.

Furthermore, birefringent islands produced through the birefringent islands of the invention according to the present invention can reduce the fineness of the island portion because it can be arranged in more than 500 islands in one island islands in addition to being applied to the light modulation film Not only is it very advantageous to produce microfiber, but it is possible to produce more than 500 microfiber from one island island, which can significantly reduce the production cost. In addition, the group islands-in-the-sea yarn according to the present invention can be utilized as a photochromic fiber by expressing a specific color according to the sea island ratio and fiber diameter without adding a compound causing color development such as dye due to the excellent light modulation effect.

Hereinafter, the present invention will be described in more detail.

As described above, the conventional laminated optical modulator film has an excessive increase in the number of layers of the optical layer, so that the production cost increases exponentially, and the optical performance is deteriorated due to light loss due to the structure in which the number of the layers of the optical layer is excessively formed. Therefore, there was a problem that it is difficult to mount it on the liquid crystal display device. Accordingly, when the birefringent fibers are disposed in the substrate, the light incident from the light source is reflected , scattered, and refracted at the birefringent interface, which is an interface between the birefringent fibers and the isotropic substrate , thereby generating light modulation, thereby improving luminance. However, when the general birefringent fibers are used, they are not manufactured in a laminated type, and thus, production costs are low and easy to produce.

Accordingly, when the optical modulation film including the birefringent island-in-the-sea yarn is mounted as a birefringent fiber having the birefringent interface in the liquid crystal display device, it is advantageous to overcome the above problems. Specifically, when the birefringent island-in-the-sea yarn was used, it was confirmed that the effect of improving the light modulation efficiency and luminance was significantly improved than when using the conventional birefringent fibers. The seam portion constituting the island-in-the-sea yarn has anisotropy, and the sea portion partitioning the seam portion has isotropy. In this case, not only the interface between the island-in-the-sea yarn and the base material, but also the interface between the islands and sea portions of the island-in-the-sea yarn has a birefringent interface, so that a birefringent interface is generated only at the interface between the base material and the birefringent fibers. The optical modulation effect is remarkably increased compared to the fiber to replace the laminated optical modulation film can be applied to actual industrial sites. Therefore, the use of birefringent island-in-the-sea yarn is superior to the use of conventional birefringent fibers, and the efficiency of brightness enhancement is excellent. What can form an interface is that the brightness enhancement efficiency can be remarkably improved as compared with the case where it is not.

On the other hand, in order to maximize the light modulation efficiency, the larger the area of the birefringent interface in the birefringent islands, the greater the advantage, for this purpose, the number of islands in the birefringent islands should be larger. However, the conventional islands and islands are arranged concentrically around a single spinning core inside the islands, and the structure of such a cross section is fine when the number of the islands is small, but when the number of islands increases (about 300 or more), in the case of the island portion adjacent to the spinning core formed in the center of the island, the density becomes large, and the phenomenon of agglomeration (conjugation phenomenon) occurs in the portion of the coating located around the spinning core during the spinning process. More specifically, FIGS. 2A and 2B are cross-sectional views of the conventional islands of the sea island (Fig. 331), and Fig. 2A shows concave portions 22 arranged concentrically around a single spinning core 21 inside the island. The cross-sectional area occupied by the dorsal portion of the total island-in-the-sea yarn is 60 to 70%. FIG. 2B also shows that the concave portion 24 is arranged concentrically around a single spinning core 23 in the island-in-the-sea yarn, and the cross-sectional area of the island-in-the-sea yarn is 70 to 80%. This cross-sectional structure is not abnormal when the number of islands is small, but when the number of islands is increased (about 300 or more) or when the ratio of the cross-sectional area of the islands of the islands is increased, the radiation core formed at the center of the islands In the case of the portion adjacent to (21), the density becomes large, and in the spinning process, the phenomenon of agglomeration between the portion located around the spinning core occurs. In other words, as the number of islands of islands in the sea island increases, there is a side effect (conjugation phenomenon) in which the island parts of the islands of the islands agglomerate to form a mass.

Therefore, the birefringent island-in-the-sea yarn having a cross-sectional shape of a conventional island-in-the-sea yarn has a problem in that the birefringence interface is reduced due to the degree of conduction.

Thus, the manufacturing method of the optical modulation film according to an embodiment of the present invention is a method of manufacturing an optical modulation film comprising the step of placing the fabric between the substrate and the substrate, wherein the fabric is two or more spinning parts A birefringent island-in-the-sea yarn that is arranged around the core to form a partitioned group is included as a weft or warp yarn to solve the above problems. In this case, in the birefringent island-in-the-sea yarn, it is possible to prevent a phenomenon in which the conductive parts are excessively accumulated in one radiating core so as not to cause a conjugation phenomenon. As a result, it was confirmed that the light modulation and the brightness is significantly improved.

Hereinafter, the optical modulator film of the present invention will be described in detail with reference to the accompanying drawings.

3 is a view of the fabric contained in the optical modulation film of the present invention. Specifically, the birefringent islands of the present invention may be disposed in the form of a fabric as shown in FIG. In this case, the present invention provides a fabric comprising the birefringent island-in-the-sea yarn of the present invention as weft and / or warp yarn, and most preferably, the birefringent island-in-the-sea yarn of the present invention is used as the weft or warp yarn and the isotropic fibers are used as the remaining weft or warp yarn. Do. Preferably, the weft yarn or warp yarn may be 1 to 200 strands of the birefringent island-in-the-sea yarn and the isotropic fibers may be partially or entirely melted. More specifically, the melting start temperature of the island portion of the birefringent island-in-the-sea yarn may be higher than the melting temperature of the sea portion of the isotropic fibers and / or the birefringent island-in-the-sea yarn. The temperature may be at least 30 ° C. above the melting temperature of the isotropic fibers and / or sea parts. For example, in the case of the birefringent island-in-the-sea yarn, when the melting start temperature of the island portion is 230 ° C., the melting temperature of the sea portion is 142 ° C., and the melting temperature of the isotropic fiber is 142 ° C., the fabric produced therefrom is placed between the substrates. If the lamination temperature is 150 ° C. while applying heat and pressure to the substrate, the lamination temperature is higher than the melting temperature of the sea portion and the isotropic fibers, but the isotropic fibers and the sea portion are partially or completely melted, but the island portion is not melted. As a result, the isotropic fibers are melted and disappeared, thereby improving the foreign material (fiber visible) phenomenon due to the isotropic fibers in the optical modulation film including the same. That is, when the lamination process is performed between the melting temperature of the isotropic fibers and / or sea portion and the melting start temperature of the island portion of the birefringent island-in-the-sea yarn, the isotropic fibers woven by the weft or warp are melted and disappeared. Fiber visible) phenomenon can be improved.

On the other hand, the optical modulating film of the present invention includes a process of placing the fabric between the substrate and laminating it, wherein the substrate that can be used in the material includes a thermoplastic and thermosetting polymer that transmits the light wavelength of the desired range and transmits light The transparent material may be easy. Preferably suitable substrates may be amorphous or semicrystalline and may comprise homopolymers, copolymers or blends thereof. Specifically poly (carbonate) (PC); Syndiotactic and isotactic poly (styrene) (PS); Alkyl styrenes; Alkyl, aromatic and aliphatic ring containing (meth) acrylates including poly (methylmethacrylate) (PMMA) and PMMA copolymers; Ethoxylated and propoxylated (meth) acrylates; Polyfunctional (meth) acrylates; Acrylated epoxy; Epoxy; And other ethylenically unsaturated substances; Cyclic olefins and cyclic olefin copolymers; Acrylonitrile butadiene styrene (ABS); Styrene acrylonitrile copolymer (SAN); Epoxy; Poly (vinylcyclohexane); PMMA / poly (vinylfluoride) blends; Poly (phenylene oxide) alloys; Styrene block copolymers; Polyimide; Polysulfones; Poly (vinyl chloride); Poly (dimethylsiloxane) (PDMS); Polyurethane; Unsaturated polyesters; Polyethylene; Poly (propylene) (PP); Poly (alkane terephthalates) such as poly (ethylene terephthalate) (PET); Poly (alkane naphthalate) such as poly (ethylene naphthalate) (PEN); Polyamides; Ionomers; Vinyl acetate / polyethylene copolymers; Cellulose acetate; Cellulose acetate butyrate; Fluoropolymers; Poly (styrene) -poly (ethylene) copolymers; PET and PEN copolymers, including polyolefins PET and PEN; And poly (carbonate) / aliphatic PET blends. More preferably, polyethylene naphthalate (PEN), polyethylene naphthalate copolymer (co-PEN) polyethylene terephthalate (PET), polycarbonate (PC), polycarbonate alloy (PC + PCTG), 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 Melanin (UF.MF), Unsaturated polyester (UP), Silicone (SI), Elastomer, Cycloolefin polymer (COP, Japan ZEON, JSR) can be used alone or in combination. The same component as the sea portion of the island-in-the-sea yarn 31 can be used. Furthermore, the substrate may contain additives such as antioxidants, light stabilizers, heat stabilizers, lubricants, dispersants, ultraviolet absorbers, white pigments, fluorescent whitening agents, and the like, as long as the above properties are not impaired. On the other hand, the optical properties of the substrate may be isotropic.

Next, a birefringent island-in-the-sea yarn forming a weft or warp yarn in the fabric will be described in more detail. As described above, the conventional islands and islands are arranged concentrically around a single spinning core inside the islands and seams in the cross-sectional structure is no abnormal when the number of the portion is small, but the number of the portion is large When it loses (about 300 or more), the density of the island portion adjacent to the spinning core formed in the center of the island is increased, the condensation occurs in the portion of the portion located around the spinning core during the spinning process. In other words, as the number of islands of islands in the sea island increases, the islands in the center portion of the islands agglomerate to form agglomerates. Thus, when used in an optical modulation film, the birefringence interface decreases, thereby limiting the improvement of the light modulation effect.

Accordingly, in the island-in-the-sea island comprising a plurality of islands and sea portions surrounding the birefringent islands according to an embodiment of the present invention, the islands are grouped and partitioned around two or more spinning cores to be described above. I solved the problem. This prevented excessive integration of the drawing parts in one spinning core.

FIG. 4 is a birefringent island-in-the-sea yarn according to a preferred embodiment of the present invention, and two spinning cores 41 and 42 are formed inside the island-in-the-sea yarn 40 and the center portion 43 is formed around the spinning cores 41 and 42. , 44) are grouped and arranged. In other words, the convex parts 43 and 44 are arranged around the respective radiating cores 41 and 42 so that the cross section is divided by the number of the radiating cores. In this case, there is no restriction in the kind of cross-sectional shape of semi-circular, sector, circular, elliptical, polygonal and heteromorphic cross section of each group of the conductive parts 43 and 44 arranged around the radiating cores 41 and 42. The shape may be the same or different. For example, FIG. 5 illustrates a case in which four spinning cores 51, 52, 53, and 54 exist inside the island-in-the-sea yarn 50, and the arrangement shapes 55, 56, 57, and 58 of respective islands are illustrated. Are all fan-shaped, but some of the arrangements of the drawing parts may be triangles, squares, or circles that are not fan-shaped. On the other hand, in the drawings of the present disclosure, the radiation core is shown in bold as a black point, but this is only an expression for clearly showing the radiation core, which means a point that is the center of the actual group, the point is also part It can be or it can be a solution. Furthermore, the blanks inside the islands may actually be filled with islands or only sea parts.

On the other hand, the number of islands arranged in the birefringent islands of the present invention may be 38 to 1500, more preferably the total number of islands may be 500 to 1500, and to properly control the number of spinning cores In this case, most preferably, the total number of conductive parts may be 1000 to 1500. Furthermore, 10 to 300 islands may be arranged with respect to the single radiation core, and more preferably, 100 to 150 islands may be arranged, but is not limited thereto. As a result, the number of islands arranged around the one radiation core described above maximizes island islands and islands, island microfibers, and desired microfibers, and light modulation efficiency to be described later, within a range where aggregation of islands does not occur. It can be adjusted as appropriate within the range possible.

According to one preferred embodiment of the present invention, the radiation core may be one radiation reference core is located in the center of the island, the plurality of radiation peripheral cores may be arranged around it. In detail, FIG. 6 illustrates an example of a birefringent island-in-the-sea yarn according to a preferred embodiment of the present invention, in which one radiation reference core 61 is formed at the center of the island-in-the-sea yarn 60, and the center of the radiation reference core 61 is 7. Four radiation peripheral cores 62 to 68 are formed. In this case, preferably, the separation distance between the radiation reference core 61 and the plurality of radiation peripheral cores 62 to 68 may substantially coincide or not coincide. Substantially coinciding the separation distance between the core 61 and the plurality of radiation peripheral cores 62 to 68 is effective to minimize the effect of the aggregation of the islands. On the other hand, when the cross-sectional shape is elliptical, the radiation reference core 61 such that the distance between the radiation reference core 61 and the plurality of radiation peripheral cores 62 to 68 is long in the long axis direction and short in the short axis direction of the ellipse. ) And a plurality of radial peripheral cores (62 to 68) may be formed.

On the other hand, the number of the radiation peripheral core is preferably 3 to 20, more preferably 6 to 10 may be formed, as shown in Figure 6 arranged based on one radiation reference core 61 The effect is most effective when the number of the radially peripheral cores 62 to 68 is 6 to 8, and the number of the doped parts grouped to the radial reference core 61 and the radial peripheral cores 62 to 68 is 100 to 200. Excellent (Table 1).

According to a second preferred embodiment of the present invention, the spinning core may be arranged based on the center of the island-in-the-sea yarn, and more preferably, the spinning core may not be formed in the center of the island-in-the-sea yarn. Hereinafter, only characteristic features of the above two embodiments will be described except for overlapping descriptions. Specifically, Figure 7 is an example of the birefringent islands in accordance with the preferred embodiment 2 of the present invention, the radiation core (72, 73, 74, 75) is arranged on the basis of the center 71 of the islands of the islands, the center of the island 71, no spin core is formed. 8 shows three spinning cores 82, 83, 84 based on the center 81 of the island-in-the-sea yarn, and eight spinning cores 85, 86 on the outside of the three spinning cores 82, 83, 84. , 87, 88, 89, 90, 91, 92). At this time, three spinning cores 82, 83, 84 formed therein and eight spinning cores 85, 86, 87, 88, 89 formed outside of the three spinning cores 82, 83, 84. , 90, 91, 92 are all arranged with respect to the center 81 of the island-in-the-sea yarn. In this case, the number of the spinning cores is preferably 3 to 20, more preferably 6 to 10, but is not limited thereto.

Meanwhile, as can be seen in FIG. 8, the birefringent islands of the present invention may have a maximum value of the center distance between adjacent islands within the same group less than a maximum value of the center distance between adjacent islands between adjacent (adjacent) groups. have. More specifically, in FIG. 8, the center distance between the neighboring drawing parts belonging to different groups from each other is the closest part d ₃ and the farthest part d ₂ . In this case, the maximum value d ₁ of the central distance of adjacent islands in the same group may be smaller than d ₂ , and thus empty spaces a ₁ and a ₂ are generated due to the separation between the groups. In other words, since the birefringent islands in the present invention do not have a constant distance between the adjacent groups formed therebetween, the distance between the adjacent islands (center distance between adjacent islands belonging to different groups) The longest part of the center distance is larger than the maximum value of the center distance of adjacent islands within the same group. Therefore, simply changing the shape of the drawing part is merely a repetition of a simple pattern, so that the joining cannot be avoided and does not belong to the partitioned group of the present invention.

On the other hand, the fineness of the group type island-in-the-sea yarn used in the present invention satisfies the single yarn fineness of a conventional island-in-the-sea yarn, but preferably may have a single yarn fineness of 0.5 to 30 denier. It is advantageous to achieve the object of the present invention that the single yarn fineness of the island portion of the island-in-the-sea yarn is 0.0001 to 1.0 denier.

In order to maximize light modulation efficiency, the birefringent island-in-the-sea yarn according to another embodiment of the present invention may have different optical characteristics of the island portion and the sea portion (optical modulation interface formation), and more preferably, the island portion is anisotropic. And the sea portion may be isotropic.

Specifically, in an island-in-the-sea island comprising an optically isotropic sea portion and an island portion having anisotropy, the magnitude of the substantial coincidence or mismatch of the refractive indices along the X, Y, and Z axes in space affects the degree of scattering of the polarized light along the axis. Crazy In general, the scattering power varies in proportion to the square of the refractive index mismatch. Thus, the greater the degree of mismatch in refractive index along a particular axis, the more strongly scattered light polarized along that axis. Conversely, when the mismatch along a particular axis is small, the light polarized along that axis is scattered to a lesser extent. If the refractive index of the sea portion along a certain axis substantially coincides with the refractive index of the island portion, the incident light polarized by an electric field parallel to this axis will not be scattered regardless of the size, shape, and density of the portion of the island. Will pass. Also, when the refractive indices along that axis are substantially coincident, the light beam passes through the object without being substantially scattered. More specifically, FIG. 9 is a cross-sectional view showing a path of light transmitted through the birefringent island-in-the-sea yarn of the present invention. In this case, the P wave (solid line) is transmitted without affecting the interface between the birefringent island-in-the-sea yarn and the birefringence interface of the seam and sea portion inside the birefringent island-in-the-sea yarn, but the S-wave (dotted line) is transmitted to the substrate and the birefringence. The modulation of light occurs due to the influence of the birefringent interface between the boundary surface of the island and the sea portion inside the birefringent islands and / or the birefringent islands.

The above-mentioned light modulation phenomenon at the birefringent interface mainly occurs at the interface between the substrate and the sea portion within the interface between the substrate and the birefringent island-in-the-sea yarn and inside the birefringent island-in-the-sea yarn. Specifically, when the optical property of the base material is isotropic, light modulation occurs at the interface between the base material and the birefringent island-in-the-sea yarn as in the case of ordinary birefringent fibers. Specifically, the refractive index of the substrate and the birefringent island-in-the-sea yarn may have a difference in refractive index of 0.05 or less in two axial directions, and a difference in refractive index of the other one axial direction of 0.1 or more. More specifically, when the refractive index in the x-axis direction of the substrate is nX1, the refractive index in the y-axis direction is nY1 and the refractive index in the z-axis direction is nZ1, and the refractive indexes of the birefringent island-in-the-sea yarns are nX2, nY2 and nZ2, At least one of the X, Y, and Z-axis refractive indices of the island-in-the-sea yarn may coincide, and the refractive index of the birefringent island-in-the-sea yarn may be nX2> nY2 = nZ2.

On the other hand, in the present invention, the optical quality of the island portion and the sea portion of the birefringent island-in-the-sea yarn is advantageous to create a birefringent interface. Specifically, when the island portion is anisotropic and the sea portion is isotropic, a birefringence interface may be formed at the interface between the island portion and the sea portion, and more preferably, the refractive index may be 0.05 or less in difference between the two indexes. It is preferable that the difference in refractive index with respect to one axial direction is 0.1 or more. In this case, P wave passes through the birefringent interface of island-in-the-sea yarn, but S wave can cause light modulation. In more detail, the refractive index in the x-axis direction in the longitudinal direction of the portion of the birefringent island-in-the-sea yarn is nX3, the refractive index in the y-axis direction is nY3, and the refractive index in the z-axis direction is nZ3, and the refractive index in the x-axis direction of the sea portion. When the refractive index in the nX4 and y-axis directions is nY4 and the refractive index in the z-axis direction is nZ4, at least one of the X, Y, and Z-axis refractive indices of the substrate and the birefringent island-in-the-sea yarn may coincide, and the refractive indices of the nX3 and nX4 The absolute value of the difference of may be 0.1 or more. Most preferably, the difference in refractive index in the longitudinal direction of the sea portion and the island portion of the island-in-the-sea yarn is 0.1 or more, and the optical modulation efficiency may be maximized when the refractive indices of the sea portion and the island portion in the remaining two axial directions substantially coincide. have. On the other hand, it is advantageous to increase the light modulation efficiency when the refractive index of the sea portion of the substrate and the birefringent islands.

As a result, in order to maximize the light modulation efficiency of the island-in-the-sea yarn as described above, the optical properties of the island portion and the sea portion should be different, and the area of the light modulation interface should be wide. For this purpose, the number of the drawing parts should be large, and preferably, the number of drawing parts should exceed 500. However, even when the refractive index of the island portion is anisotropic and the refractive index of the sea portion is arranged isotropically in the conventional islands and islands, when the number of the island portions exceeds 500, the island portion is agglomerated, and the area of the optical modulation interface is reduced and the light is reduced. There is a fatal problem of poor modulation efficiency. Thus, in the present invention, when two or more spinning cores are formed as described above, even when 500 or more, preferably 1000 or more islands are disposed, the phenomenon of bunching of islands can be prevented. As a result, the light modulation efficiency of the island-in-the-sea yarn is maximized, and when the birefringent island-in-the-sea yarn according to the embodiment of the present invention is added to the light modulation film and the light modulation film to be described later, a significant improvement in light modulation effect and luminance can be expected.

The sea portion and / or island portion of the birefringent island-in-the-sea yarn that may be used in the present invention may be 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), acrylo Nitrile Butadiene Styrene (ABS), Polyurethane (PU), Polyimide (PI), Polyvinyl Chloride (PVC), Styrene Acrylonitrile Mixture (SAN), Ethylene Vinyl Acetate (EVA), Polyamide (PA), Poly It may be at least one of acetal (POM), phenol, epoxy (EP), urea (UF), melanin (MF), unsaturated polyester (UP), silicone (SI), elastomer and cycloolefin polymer. Preferably, the material and the sea portion have substantially the same refractive index in two axial directions, but selecting a material having a large difference in refractive index in one axial direction is effective to improve the light modulation efficiency. However, most preferably, the birefringent island-in-the-sea yarn 31 uses polyethylene naphthalate (PEN) as the island portion, and copolyethylene naphthalate or polycarbonate alloy alone or mixed to be used as a sea portion as a conventional material. The luminance is remarkably improved as compared to the birefringent island-in-the-sea yarn set out in Article 3. In particular, when the polycarbonate alloy (alloy) is used as the sea portion, it is possible to produce a birefringent island-in-the-sea yarn having the best optical modulation properties. In this case, the polycarbonate alloy may be preferably composed of polycarbonate and modified glycol polycyclohexylene dimethylene terephthalate (PCTG), and more preferably modified with polycarbonate. It is effective to increase the luminance by using a polycarbonate alloy having a glycol polycyclohexylene dimethylene terephthalate (PCTG) in a weight ratio of 15:85 to 85:15. If the polycarbonate is added less than 15%, the viscosity of the polymer required to secure the radioactivity is high, and the ordinary spinning machine cannot be used. If the polycarbonate is more than 85%, the glass transition temperature increases, and after the nozzle discharge, the radiation tension increases to secure radioactivity. Has a difficult problem.

Most preferably, the polycarbonate and the modified glycol polycyclohexylene dimethylene terephthalate (PCTG) in a weight ratio of 4: 6 to 6: 4 exhibit the best effect on brightness enhancement. Furthermore, it is effective to improve the light modulation efficiency by selecting a material in which the refractive index in the two axial directions is substantially the same, but the difference in the refractive index in the one axial direction is large.

On the other hand, a method for changing an isotropic material to birefringence is commonly known and, for example, when drawn under suitable temperature conditions, the polymer molecules are oriented so that the material becomes birefringent.

Preferably, the material and the sea portion have substantially the same refractive index in two axial directions, but selecting a material having a large difference in refractive index in one axial direction is effective to improve the light modulation efficiency.

Furthermore, the birefringent island-in-the-sea yarn may have 500 to 4,000,000 pieces in 1 c㎥ of the optical modulation film. The cross-sectional diameter of the islands within the birefringent islands can also have a significant effect on light modulation. When the diameter of the cross-section of each birefringent island-in-the-sea island is smaller than the wavelength of light, the effects of refraction, scattering, and reflection decrease, and light modulation hardly occurs. If the cross section diameter of the island portion is too large, light is specularly reflected from the surface of the island-in-the-sea yarn and diffusion in other directions is very small. The cross-sectional diameter of the aligned portion may vary depending on the intended use of the optics. For example, the diameter of the fiber can vary depending on the wavelength of electromagnetic radiation important for a particular application, and different fiber diameters are required to reflect, scatter or transmit visible, ultraviolet, infrared and microwave radiation.

On the other hand, according to a preferred embodiment of the present invention, the optical modulation film of the present invention may have a structured surface layer on its surface, and more specifically, the structured surface layer may be formed on the surface from which light is emitted. The structured surface layer may be prismatic, lenticular or convex. Specifically, the surface on which the light is emitted on the light modulation film may have a curved surface having a convex lens shape. The curved surface may focus or defocus light transmitted through the surface. In addition, the light exit surface may have a prism pattern.

Next, the method of manufacturing the birefringent island-in-the-sea yarn of the present invention will be described. The birefringent island-in-the-sea yarn of the present invention can be applied without any limitation as long as it is a method capable of producing a conventional island-in-the-sea yarn such as a composite spinning process. The spinnerets and spinnerets used can be used as long as they can produce birefringent islands, but generally the spinnerets and yarns are designed to substantially match the arrangement of the islands in the cross-section of the birefringent islands. Can be used. Specifically, a sea component flowed from a flow channel designed to fill the gap between the island component extruded from a hollow pin or a spinning nozzle appropriately designed to allow the island portion to be partitioned inside the spinneret, and the flow of water It is possible to form an island-in-the-sea yarn by extruding from the discharge port while gradually thinning, and any spinneret can be used as long as the island-in-the-sea yarn includes two or more spinning centers. 10 and 11 illustrate an example of spinnerets that are preferably used, but spinnerets that can be used in the method of the present invention are not necessarily limited thereto, and spinnerets disclosed in Korean Patent Application No. 2009-12138 Through the birefringent islands of the present invention can be produced.

Specifically, Figure 10 is an example of a preferred spinneret that can be applied to the present invention. Specifically, in the spinneret 100, the conductive polymer (molten body) in the conductive polymer storage portion 101 before distribution is distributed in the conductive polymer introduction passage 102 formed by the plurality of hollow pins, The sea component polymer (melt) is introduced into the sea component polymer storage section 104 before dispensing through the sea component polymer introduction passage 103. The hollow pins forming the island component polymer introduction passage 102 respectively penetrate through the polymer storage portion 104 for sea component, and are located at the centers of the respective inlets of the plural ecchotype compound flow passages 105 formed thereunder. It is open downward. The island component polymers are introduced into the central portion of the vinegar composite flow passage 105 from the lower end of the island component polymer introduction passage 102, and the sea component polymers in the sea component polymer storage section 104 are the passages for the vinegar composite flow passage. In 105, a core component is introduced so as to surround the island component polymers, and the sea component polymers are formed with sea component polymers as a seam, and the core portion is centered on two or more radiation centers. The core parts are grouped and arranged. After the plural cardiac complexes are introduced into the funnel-shaped confluence passage 106, in the confluence passage 106, the pleural pleated complexes are joined to each other by the seaweed-shaped complex flows. do. This island-in-the-sea composite flow gradually decreases the cross-sectional area in the horizontal direction while flowing inside the funnel-shaped confluence passage 106 and is discharged from the discharge port 107 at the lower end of the confluence passage 106.

11 is an example of another preferred spinneret 110 of the present invention, wherein the island component polymer storage section 111 and the sea component polymer storage section 112 are formed of a plurality of transmission holes. Connected to each other, the island-based polymer (melt) in the island-based polymer storage 111 is distributed in the plurality of island-based polymer introduction passages 113 and introduced therethrough into the sea-component polymer storage 112. . Meanwhile, the sea component polymer is accommodated in the sea component polymer storage 112 through the sea component polymer furnace 115. On the other hand, the island component polymers introduced into the sea component polymer storage section 112 penetrate through the sea component polymer (melt) accommodated in the sea component polymer storage section 112 and enter into the aquatic composite flow passage 114. After it flows in, it flows down the central part. On the other hand, the sea component polymer in the sea component polymer storage part 112 flows down to surround the island component polymers which flow down the center part in the deep-sea type composite flow passage 114. As a result, in the plurality of edible-type composite flow passages 114, a plurality of edible-type composite flows are formed, and flow down into the funnel-shaped confluence passage 116, and eventually, the island-in-the-sea composite as in the spinneret of FIG. A stream is formed and flows down while decreasing the cross-sectional area in the horizontal direction, and is discharged through the discharge port 117 to finally produce the birefringent island-in-the-sea yarn of the present invention.

As a result, the birefringent island-in-the-sea yarn of the present invention, unlike the conventional islands-in-the-sea yarn, does not generate agglomeration of island portions, so that the number of island portions can be arranged to 1000 or more, so that a large number of birefringent interfaces can be formed. It is particularly effective for improving modulation efficiency and enhancing luminance.

Furthermore, in the case of producing a composite fiber by twisting multiple strands or dozens of islands, for example, when manufacturing one composite fiber by twisting 10 islands or yarns, the composite fiber has 100 birefringent interfaces and at least 100 times of light. Modulation can occur. In addition, in the case of manufacturing the island-in-the-sea yarn spun into several strands, for example, if the island-in-the-sea yarn of 10 strands is manufactured, 100 birefringent interfaces exist in the composite fiber, and at least 100 light modulations may occur. The island-in-the-sea yarn of the present invention may be manufactured by a coextrusion method, but is not limited thereto.

Therefore, if the conventional island-in-the-sea yarn utilizes the remaining island portion as a micro-fine fiber by eluting the sea portion regardless of whether it is birefringent or not to produce the microfiber yarn, in the present invention, the sea portion and island portion are not eluted. It is assumed that the island-in-the-sea yarn having different optical properties is used by itself. In the present invention, only the case where the island portion is composed of anisotropy and the sea portion is isotropic is assumed, but the object of the present invention may be achieved in the opposite case. .

On the other hand, after manufacturing a fabric comprising a birefringent island-in-the-sea yarn having the above-described configuration can be produced the optical modulating film of the present invention through the process of placing the fabric between the substrate and laminating. In this case, preferably, the lamination process may be performed by pressing and heating using a vacuum hot press equipment. Specifically, Figure 12a is a SEM photograph of the light modulating film after performing the lamination process in a vacuum state using a vacuum hot press, Figure 12b, 12c is a light modulated film after performing the lamination process in the air using a common hot press When the lamination process is performed on a vacuum hot press, the pores rarely occur in the film. However, when the lamination process is performed in air using a general hot press, a pore occurs. Therefore, carrying out the lamination process through vacuum hot press is very important to provide a light modulation film having excellent reliability by preventing curl phenomenon and improving adhesion performance.

In this case, the degree of vacuum in the pressurizing and heating steps is 5 to 500 torr, the applied pressure is 1.0 to 100 kgf / cm ² , the temperature is 80 to 160 ° C., and the process time is preferably 1 to 30 minutes. If the vacuum degree is less than 5 torr, there is a fear that the process efficiency is lowered, and if it exceeds 500 torr, there is a fear that bubble removal is insufficient. In addition, the applied pressure is 1.0kgf / cm ² Less than When the adhesion of the film may not be sufficient and when it exceeds 100 kgf / cm ² , the pressure may be excessive to disturb the tissue of the fabric and collapse the arrangement of the fibers. When the heating temperature is lower than 120 ° C., the adhesion of the film may not be sufficient. If the heating temperature is higher than 180 ° C., the substrate or the birefringent islands may be crystallized or melted. When the process time is less than 1 minute, the bubble removal and adhesion may be It may be insufficient, and when it exceeds 30 minutes, it is not preferable in terms of process efficiency.

On the other hand, the configuration of the liquid crystal display device including the optical modulator film of the present invention with reference to FIG. 13 as an example of the liquid crystal display device employing the optical modulator film of the present invention, the reflecting plate 220 on the frame 210 Is inserted, the cold cathode fluorescent lamp 230 is located on the upper surface of the reflecting plate 220. An optical film 240 is positioned on an upper surface of the cold cathode fluorescent lamp 230, and the optical film 240 includes a diffusion plate 241, a light diffusion film 242, a prism film 243, and a light modulation film ( 244 and the absorption polarizing film 245, but the order of stacking may vary depending on the purpose, some components may be omitted, or a plurality may be provided. For example, the diffusion plate 241, the light diffusing film 242, the prism film 243, and the like may be excluded from the overall configuration and may be changed in order or formed at different positions. Furthermore, a retardation film (not shown) or the like may also be inserted at an appropriate position in the liquid crystal display device. Meanwhile, the liquid crystal display panel 260 may be inserted into the mold frame 250 on the upper surface of the optical film 240.

Looking at the center of the light path, the light irradiated from the backlight 230 reaches the diffusion plate 241 of the optical film 240. The light transmitted through the diffuser plate 241 passes through the light diffusion film 242 to advance the light propagation direction perpendicular to the optical film 240. The film passing through the light diffusing film 242 passes through the prism film 243 and reaches the light modulating film 244 to generate light modulation. Specifically, the P wave transmits the light modulating film 244 without loss, but in the case of the S wave, light modulation (reflection, scattering, refraction, etc.) is generated, and thus the reflection wave 220 is the back surface of the cold cathode fluorescent lamp 230. After being reflected and the nature of the light is randomly changed to P wave or S wave, it passes through the light modulating film 244 again. After passing through the absorption polarizing film 245, the liquid crystal display panel 260 is reached. As a result, when the optical modulation film of the present invention is used by being inserted into a liquid crystal display device, it is possible to expect a significant improvement in luminance compared to a conventional optical modulation film. In addition, the cold cathode fluorescent lamp 230 may be used instead of the LED as a light source.

On the other hand, the birefringent island-in-the-sea yarn included in the optical modulation film of the present invention not only prevents the phenomenon of over-integration in one radiation core when included in the optical modulation film, but also when used as the fiber itself. Since more than 500 islands can be placed in the islands, the fineness of the islands can be reduced, which is very advantageous to produce microfiber yarns. Can be. In addition, the group islands-in-the-sea yarn according to the present invention can be utilized as a photochromic fiber by expressing a specific color according to the sea island ratio and fiber diameter without adding a compound causing color development such as dye due to the excellent light modulation effect.

Hereinafter, the present invention will be described in detail by Examples and Experimental Examples. The following Examples and Experimental Examples are only illustrative of the present invention, and the scope of the present invention is not limited to the following Examples and Experimental Examples.

≪ Example 1 >

An isotropic PC alloy in which polycarbonate and modified glycol polycyclohexylene dimethylene terephthalate (PCTG) is mixed at 5: 5 as a sea component (nx = 1.57, ny = 1.57, nz = 1.57), and anisotropic PEN (nx = 1.88, ny = 1.57, nz = 1.57). In order to obtain the island-in-the-sea yarn of the cross section as shown in FIG. Through this composition, the undrawn yarn 150/24 was spun under the condition of spinning temperature of 305 ° C. and the spinning speed of 1500 M / min, and then the drawn yarn 50/24 was obtained by three times stretching. The group-shaped island-in-the-sea yarn manufactured as described above is arranged in two spinning cores, each of which has 200 islands each grouped into 100 pieces. Was woven into a fabric. Thereafter, the island-in-the-sea yarn fabric is placed between two PC alloy sheets made of the same material as the sea portion of the birefringent island-in-the-sea yarn, and then pressurized with a constant tension to laminate the woven fabric with the island-in-the-sea yarn inside the Pc alloy sheet. I was. Subsequently, a mixed UV cured coating resin of an epoxy acrylate having a refractive index of 1.54 and a urethane acrylate is given to the point where the fiber is laminated to the PC alloy sheet and the mirror roll, and UV cured through primary and secondary birefringence. A fused sheet was prepared in which the island-in-the-sea yarn was laminated. The coating resin exhibits a refractive index of 1.54 before the UV coating curing but a refractive index of 1.57 after curing. Through this, a light modulated film having a thickness of 400 μm was prepared.

<Example 2>

Light modulation is carried out in the same manner as in Example 1 except that the cross-sectional shape of the island-in-the-sea yarn corresponds to FIG. 6 and 130 birefringent island-in-the-sea yarns are arranged in one radiating core and the total number of the island portions is 1040. A film was prepared.

<Example 3>

The optical modulation was carried out in the same manner as in Example 1 except that the cross-sectional shape of the island-in-the-sea yarn corresponds to FIG. 8 and the birefringent island-in-the-sea yarn having 100 islands were arranged in one spinning core and the total number of islands was 1100. A film was prepared.

Comparative Example 1

Except that the island portion is isotropic PET (nx = ny = nz = 1.57), the sea portion is isotropic C0-PEN (nx = ny = nz = 1.57), and sea island yarn having a cross section of the island-in-the-sea yarn corresponding to FIG. 4 is used. In the same manner as in Example 1, a light modulating film having a thickness of 400 μm was prepared.

Comparative Example 2

After superposing | polymerizing the PEN resin of IV 0.53 instead of the birefringent island-in-the-sea yarn of Example 1, the yarn of the unstretched yarn 150/24 was produced. At this time, the spinning temperature was 305 ℃, spinning speed was applied by applying 1500 M / min. The obtained undrawn yarn was stretched three times at a temperature of 150 ° C. to produce 50/24 drawn yarn. The stretched PEN fibers exhibit birefringence and the refractive indices in each direction are nx = 1.88, ny = 1.57, and nz = 1.57. Except for including the birefringent PEN fibers in place of the island-in-the-sea yarn of Example 1 was carried out in the same manner as in Example 1 to prepare a light modulation film having a thickness of 400㎛.

Comparative Example 3

Light modulation is performed in the same manner as in Example 1 except for using the island-in-the-sea yarn having one spinning core and 200 islands arranged around the birefringent island-in-the-sea yarn as shown in FIG. 2A. A film was prepared.

<Comparative Example 4>

Light modulation is carried out in the same manner as in Example 1 except for using the island-in-the-sea yarn having one spinning core and 500 islands arranged around the birefringent island-in-the-sea yarn as shown in FIG. 2B. A film was prepared.

Experimental Example

Examples 1 to 3 and Comparative Examples 1 to 4 for the optical modulated film prepared through the following physical properties were evaluated and the results are shown in Table 1.

1. Luminance

In order to measure the brightness of the prepared optical modulation film was performed as follows. After assembling the panel on the 32 "direct type backlight unit equipped with a diffuser plate, two diffusion sheets, and a light modulating film, the average value was measured by measuring the luminance at nine points using a BM-7 measuring instrument from Topcon.

2. Transmittance

Permeability was measured by ASTM D1003 method using COH300A analysis equipment of NIPPON DENSHOKU, Japan.

3. Polarization degree

The degree of polarization was measured using an OTSKA RETS-100 analyzer.

4. Water absorption rate

The change in weight percent of the sample before and after the treatment was measured after immersion in water at 23 ° C. for 24 hours according to ASTM D570.

5. Seatum

       The light modulator film was assembled in a 32-inch backlight unit, left in a constant temperature and humidity chamber at 60 ° C. and 75% for 96 hours, and then decomposed and visually observed the degree of occurrence of the light modulator film was divided into ○, △, and ×.

        ○: Good, △: Normal, ×: Poor

6. UV resistance

       After irradiating the output of 130mW UV lamp (365nm) for 10 minutes at 10cm height using Semyung Baektron's SMDT51H, YI (Yellow Index) before and after treatment was measured by using NIPPON DENSHOKU's SD-5000 analysis equipment. Yellowness was evaluated.

[Table 1]

Brightness (cd / m 2) Transmittance (%) % Polarization Absorption rate (%) Sheet help UV resistance Example 1 400 52 78 0.24 O 2.3 Example 2 420 48 80 0.24 O 2.0 Example 3 420 48 80 0.24 O 2.0 Comparative Example 1 290 85 5 0.24 O 1.5 Comparative Example 2 320 55 50 0.24 O 1.8 Comparative Example 3 380 58 70 0.24 O 2.0 Comparative Example 4 390 56 72 0.24 O 2.0

As can be seen from Table 1, the optical modulator film (Examples 1 to 3) including the birefringent island-in-the-sea yarn of the present invention was superior to the overall optical properties compared to Comparative Examples 1 to 4 without using it. In particular, as shown in Example 2, the best effect was to use the island-in-the-sea yarn having the cross section as shown in FIG.

On the other hand, as can be seen from Comparative Example 1, even when the birefringent island-in-the-sea yarn cross section of the present invention is adopted, when the optical properties of the island portion and the sea portion are the same, the effect of brightness enhancement hardly occurs. Even when the optical properties were different, the optical properties were poor even when the shape of the cross section of a normal island-in-the-sea yarn having one radiation core was adopted. Through this, it can be seen that the optical properties of the island portion and sea portion are different, but the cross-sectional shape has very excellent optical properties when the shape of the birefringent island-in-the-sea yarn of the present invention is adopted.

Since the optical modulation film of the present invention has excellent optical modulation performance, the optical modulation film may be mounted and used in an optical device such as a camera and a liquid crystal display device requiring high brightness such as a mobile phone, an LCD, an LED TV, a monitor, and the like.

Although the present invention has been described in detail only with respect to the described embodiments, it will be apparent to those skilled in the art that various modifications and variations are possible within the technical spirit of the present invention, and such modifications and modifications belong to the appended claims. .

1 is a schematic view illustrating the principle of a conventional optical modulation film.

2A and 2B are electron micrographs of a conventional islands-in-the-sea cross-section.

3 is a woven fabric using the birefringent island-in-the-sea yarn of the present invention as weft and / or warp yarns.

4 is a cross-sectional view of a group island-in-the-sea yarn according to a preferred embodiment of the present invention.

5 is a cross-sectional view of a group island-in-the-sea yarn according to another preferred embodiment of the present invention.

6 is an electron micrograph of a group islands-in-the-sea yarn according to another preferred embodiment of the present invention.

7 is a cross-sectional view of a group island-in-the-sea yarn according to another preferred embodiment of the present invention.

8 is a cross-sectional view of a group island-in-the-sea yarn according to another preferred embodiment of the present invention.

9 is a cross-sectional view showing a path of light incident on the birefringent island-in-the-sea yarn of the present invention.

10 is a cross-sectional view of a portion of the spinneret according to a preferred embodiment of the present invention.

11 is a cross-sectional view of a portion of a spinneret according to another preferred embodiment of the present invention.

12A is a SEM photograph of a light modulating film after performing a lamination process in a vacuum state using a vacuum hot press, and FIGS. 12B and 12C are SEM images of a light modulating film after performing a lamination process in air using a general hot press. It is a photograph.

13 is an exploded perspective view of a liquid crystal display device including the optical modulation film of the present invention.

Claims (34)

A method of manufacturing an optical modulating film comprising placing a fabric between substrates and laminating the substrate, wherein the fabric has a birefringent island-in-the-sea yarn having a portion arranged around two or more spinning cores to form a partitioned group. It includes a weft or warp, the other isotropic fiber and the isotropic fiber is a method of manufacturing a light modulating film, characterized in that some or all of the melted. The method of claim 1, wherein the laminating step is performed in a vacuum hot press. The method of claim 2, wherein the laminating step is performed at a vacuum degree of 5 to 500 torr. delete The method of claim 1, wherein the melting start temperature of the island portion of the birefringent island-in-the-sea yarn is higher than the melting temperature of the sea portion of the isotropic fibers and the birefringent island-in-the-sea yarn. The method of claim 1, wherein the melting start temperature of the island portion of the birefringent island-in-the-sea yarn is 30 ° C or more higher than the melting temperature of the sea portion of the isotropic fibers and the birefringent island-in-the-sea yarn. The method of claim 5, wherein the lamination process is performed at the temperature condition of the following relation 1. [Relationship 1] Melting temperature of isotropic fibers (℃) <Lamination temperature (℃) <Melting start temperature of islands in islands delete The method of claim 1, wherein the weft or warp is a method for manufacturing an optical modulation film, characterized in that the island-in-the-sea yarn is formed by gathering 1 ~ 200 strands. The method of claim 1, wherein the radiation core has one radiation reference core positioned at the center of the birefringent island-in-the-sea yarn and a plurality of radiation peripheral cores are arranged around the radiation core. The method of claim 10, wherein the separation distance between the radiation reference core and the plurality of radiation peripheral cores is the same or different. The method of claim 10, wherein the radiation peripheral core is 6 to 10 characterized in that the manufacturing method of the optical modulation film. The method of claim 10, wherein the radiation reference core or one radiation peripheral core with respect to the radiation modulated film is characterized in that 10 to 300 are arranged. The method of manufacturing a light modulating film according to claim 10, wherein the total number of the drawing parts is 1000 to 1500. The method of claim 10, wherein the number of the radiating cores is 6 to 10. The method of claim 1, wherein a birefringent interface is formed at a boundary between the island portion and the sea portion of the birefringent island-in-the-sea yarn. The method of claim 16, wherein the island portion is anisotropic and the sea portion is isotropic. The method of claim 1, wherein the substrate is isotropic. The optical modulation film of claim 1, wherein the refractive index of the substrate and the birefringent island-in-the-sea yarn is 0.05 or less in two axial directions, and the difference in refractive index in one remaining axial direction is 0.1 or more. Manufacturing method. The refractive index of the island portion and the sea portion of the birefringent island-in-the-sea yarn has a difference in refractive index of 0.05 or less in the two axial directions, and a difference in refractive index of the other one axial direction of 0.1 or more. Method of manufacturing light modulating film. The method of claim 1, wherein the refractive index of the sea portion in the island-in-the-sea yarn coincides with the refractive index of the base material. The method of claim 1, The birefringent island-in-the-sea yarns are arranged around two or more radiating cores to form a partitioned group, but the maximum distance of the center distance between adjacent islands within the same group is the center distance between adjacent islands between groups. Method for producing a light modulated film, characterized in that less than the maximum value of. delete delete delete delete delete delete delete delete delete delete delete delete

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