KR100951705B1 - Method for preparing brightness enhancement sheet and brightness enhancement sheet prepared by the same - Google Patents

Abstract

PURPOSE: By using a simple method for passing through macromolecular film formed in both sides of fabric between lamination roll manufacturing method of brightness enhancement sheet and brightness enhancement sheet manufactured thereby increases productivity and profitability. CONSTITUTION: By passing through fabric and material between lamination rolls the materials is laminated in the fabric including the birefringence. The sheet is formed by laminating the materials in fabric. The material is laminated in both sides of fabric. Fabric and materials are provided through the respective unwinding rolls(871, 872, 873) to lamination rolls. The lamination roll comprises the heating portion and cooling part. The temperature of the upper heating part is 100°C to 300°C.

Description

Method for preparing brightness enhancement sheet and brightness enhancement sheet produced by the same {Method for preparing brightness enhancement sheet and brightness enhancement sheet prepared by the same}

The present invention relates to a method for manufacturing a luminance-reinforced sheet including a fabric woven with birefringent islands and a polymer film, a sheet in which a polymer film is laminated on a fabric woven with a birefringent island-in-the-sea yarn by passing the fabric and the polymer film between lamination rolls The present invention relates to a method for manufacturing a luminance-enhanced sheet characterized in that it forms a light, thereby improving the light efficiency and adhesion performance.

In information display technology, the display device has occupied the CRT position for more than half a century. However, in the rapidly developing information age, various types of display technologies are required. Among them, flat panel display is expected to become a technology that surpasses CRT in the near future. Already, portable computers, as well as small measuring instruments, have become popular, and existing CRT methods, including various monitors and TVs, are being replaced by flattening.

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 the TV field, 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. Therefore, in order to increase the utilization efficiency of the backlight light in the liquid crystal display device, a brightness enhancing film is provided between the optical cavity and the liquid crystal assembly.

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

Specifically, P-polarized light from the optical cavity to the liquid crystal assembly passes through the luminance-enhanced film to be transmitted to the liquid crystal assembly, and S-polarized light is reflected from the luminance-enhanced film to the optical cavity, and then the light is reflected on the diffuse reflection surface of the optical cavity. The polarization direction is reflected in a randomized state and then transmitted to the luminance-enhanced film, which eventually converts the S-polarized light into P-polarized light that can pass through the polarizer of the liquid crystal assembly, and then passes the luminance-enhanced film 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 luminance-enhanced film have a refractive index 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 luminance-enhanced film repeats the reflection of S-polarized light and the transmission of P-polarized light while passing 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 luminance-enhanced film as described above. As a result, power loss can be reduced together with the loss of light generated from the light source.

However, such a conventional brightness enhancement film is laminated with anisotropic optical layer and anisotropic optical layer on a 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 luminance-enhanced film is complicated. In particular, since each optical layer of the luminance-enhanced film has a flat plate structure, it is necessary to separate P-polarized light and S-polarized light in response to a wide range of incidence angles of 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 luminance-enhanced film by inserting birefringent fibers into the substrate has been disclosed. In this case, the general birefringent fibers are not manufactured in a laminated form, so the production cost is low and the production is easy. However, there is a problem that it is difficult to be applied to an industrial site in place of the laminated luminance-enhanced film described above because the effect of brightness enhancement is insignificant. Was found.

The first object of the present invention is a method for producing a luminance-reinforced sheet comprising a fabric and a polymer film woven with birefringent island-in-the-sea yarn, a luminance-enhanced film improved adhesion and reliability by passing the fabric and the polymer film between the lamination rolls It is to provide a manufacturing method.

It is a second object of the present invention to provide a brightness enhancing sheet manufactured by the above manufacturing method.

A third object of the present invention is to provide a display device including the luminance-enhanced sheet manufactured by the manufacturing method.

In order to solve the first problem, the present invention is a method of manufacturing a luminance-reinforced sheet comprising a fabric and a substrate comprising a birefringent islands, the fabric and the substrate is passed through a lamination roll to the birefringent islands Provided is a method for producing a luminance-enhanced sheet, characterized in that to form a sheet laminated the substrate on the fabric comprising.

According to one embodiment of the invention, the substrate is preferably laminated on both sides of the fabric.

In addition, according to another embodiment of the present invention, the lamination roll may have a heating unit and a cooling unit therein, the temperature of the heating unit is preferably 100 ℃ to 300 ℃, the temperature of the cooling unit is 60 ℃ to 180 It is preferable that it is ° C.

In addition, according to another embodiment of the present invention, it is preferable that the speed of the lamination roll is from 1 to 50 m / min, the fabric and the substrate is generally supplied to the lamination roll through the unwinding roll, respectively.

In addition, according to another embodiment of the present invention, it may further comprise the step of forming a three-dimensional structured pattern on the surface of the luminance-enhanced sheet, such a pattern is a hemispherical, prismatic, or lenticular pattern formed repeatedly, for example You can choose from.

In addition, according to another embodiment of the present invention, the fabric can be woven using either a birefringent island-in-the-sea yarn and one of the warp and weft yarns, and the other is a non-birefringent yarn. In this case, the fabric is preferably asymmetrical so that the birefringent island-in-the-sea yarn is more exposed to the surface than the non-birefringent yarn. Here, the asymmetric structure, one non-birefringent yarn per 5 to 16 birefringent island-in-the-sea yarn in the advancing direction of the non-birefringent yarn is exposed to the surface, or the birefringent island-in-the-sea yarn is 5 than the non-birefringent yarn To 16 times more exposed to the surface.

According to another embodiment of the present invention, the birefringent island-in-the-sea yarn is 100 to 240 pieces / inch, and the non-birefringent yarn may be woven to 20 to 240 pieces / inch. In addition, the birefringent island-in-the-sea yarn may be formed by gathering 1 to 200 strands of birefringent island-in-the-sea single yarn, wherein the fineness of the birefringent island-in-the-sea yarn is preferably 5 to 500 denier, and the birefringent island-in-the-sea yarn It is preferable that a fineness is 0.5-30 denier. In addition, the birefringent islands-in-the-sea yarn may be made of 2 to 1500 pieces, and the degree of fineness of the islands of the birefringent islands-in-the-sea yarn may be 0.0001 to 1.0 denier.

In addition, according to another embodiment of the present invention, the non-birefringent yarn is preferably isotropic fibers.

According to another embodiment of the present invention, it is preferable that the birefringent island-in-the-sea yarn have different optical characteristics of the island portion and the sea portion. For example, the island portion may be anisotropic and the sea portion may be isotropic.

In addition, the island portion or sea portion of the birefringent island-in-the-sea yarn is polyethylene naphthalate, copolyethylene naphthalate, polyethylene terephthalate, polycarbonate, polycarbonate alloy, polystyrene, heat-resistant polystyrene, polymethyl methacrylate, polybutylene tere Phthalate, Polypropylene, Polyethylene, Acrylonitrile Butadiene Styrene, Polyurethane, Polyimide, Polyvinylchloride, Styrene Acrylonitrile Blend, Ethylene Vinyl Acetate, Polyamide, Polyacetal, Phenol, Epoxy, Urea, Melanin, Unsaturated Poly It may be selected from the group consisting of esters, silicones, elastomers and cycloolefin polymers.

According to another embodiment of the present invention, the refractive index of the birefringent islands-in-the-sea yarn and the island portion has a difference in refractive index of 0.03 or less in two axial directions, and a difference in refractive index in one axial direction. 0.05 or more. In addition, 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 to 8: 2.

In addition, according to another embodiment of the present invention, the birefringent islands-in-the-sea yarn may be arranged in groups of two or more spinning cores, and in this case, one spinning reference core is positioned at the center of the spinning core. A plurality of radial peripheral cores may be arranged around this.

In addition, according to another embodiment of the present invention, it is preferable that the substrate is an isotropic substrate, and the material of the substrate may be the same as the material of the island portion or sea portion of the birefringent island-in-the-sea yarn. The substrate mainly uses a polymer film, for example polyethylene naphthalate, copolyethylene naphthalate, polyethylene terephthalate, polycarbonate, polycarbonate alloy, polystyrene, heat resistant polystyrene, polymethylmethacrylate, polybutylene terephthalate , Polypropylene, polyethylene, acrylonitrile butadiene styrene, polyurethane, polyimide, polyvinyl chloride, styrene acrylonitrile mixture, ethylene vinyl acetate, polyamide, polyacetal, phenol, epoxy, urea, melanin, unsaturated polyester At least one selected from the group consisting of silicone, elastomer, and cycloolefin polymer can be used.

In addition, according to another embodiment of the present invention, the method may further include attaching a protective film on both sides of the luminance-enhanced sheet passing through the lamination roll, in which case an OPP film or PET film may be used as the protective film. .

In order to solve the second problem, the present invention provides a luminance-enhanced sheet comprising a birefringent island-in-the-sea yarn and a substrate, characterized in that produced in the roll-to-roll method.

In order to solve the third problem, the present invention provides a liquid crystal display device comprising a brightness enhancement sheet manufactured by the roll-to-roll method.

The method for manufacturing a luminance-enhanced sheet according to the present invention can produce a luminance-enhanced sheet by a simple method of weaving birefringent island-in-the-sea yarns and passing a polymer film between lamination rolls on both sides of the fabric. In addition, the luminance-enhanced sheet manufactured by the roll-to-roll method

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings based on embodiments. However, the described embodiments are exemplary and are not intended to limit the scope of the present invention.

The luminance-enhanced sheet in the present invention is characterized by being manufactured by a roll to roll method. In general, the roll-to-roll method refers to a method of manufacturing a sheet by laminating through a fabric or a substrate for manufacturing the sheet between lamination rolls. According to the present invention there is provided a method for producing a luminance-reinforced sheet by passing the fabric and the substrate including the birefringent islands and yarns between the lamination roll, the fabric comprising birefringent islands, which are laminated on both sides of the fabric Each of the substrates will be described first, and a method of manufacturing the luminance-enhanced sheet will be exemplified.

The luminance-enhancing fabric of the present invention is one of warp and weft yarns is a birefringent island-in-the-sea yarn, and the other is a non-birefringent yarn. A birefringent island-in-the-sea yarn consists of sea and island sections. The sea component in the conventional islands-in-the-sea yarn is a component that elutes or dissolves in the post-processing process after spinning, and the island component is a component that continues to form fibers after removing the sea component. However, in the present invention, the sea component may be left without being removed.

As used herein, the term birefringent islands-in-the-sea yarn refers to a yarn used as a warp or weft of a fabric. The birefringent islands-in-the-sea yarn may consist of one island-in-the-sea single yarn, or a plurality of islands-in-sea single yarn may be twisted. Unless otherwise specified, birefringent islands-in-the-sea yarns may be used in both of the above meanings, and when it is necessary to distinguish them, the terms birefringent islands-like yarn for the former and birefringent islands-in-the-sea yarn for the latter are used.

2 is a cross-sectional view of the birefringent islands-in-the-sea yarn of the present invention. Referring to FIG. 2, a birefringent island-in-the-sea yarn includes a seam portion 220b and a sea portion 210b, and is formed in an island shape in which the seam portion 220b is isolated inside the sea portion 210b. In this case, the island portion 220b and the sea portion 210b may be made of a material having different optical characteristics. In particular, the birefringent island-in-the-sea yarn of the present invention may have different light refraction characteristics of the island portion 220b and the sea portion 210b in order to maximize the light modulation efficiency, and more preferably, the island portion 220b is anisotropic. And the portion 210b may be isotropic. Specifically, in a birefringent island-in-the-sea yarn comprising optically isotropic and anisotropic islands, the magnitude of the substantial coincidence or mismatch of the refractive indices along the X, Y and Z axes in space is the degree of scattering of polarized light along that axis. Affects. In general, the scattering power varies in proportion to the square of the refractive index mismatch. Thus, the greater the degree of mismatch of the refractive indices along a particular axis, the more strongly scattered light polarized along that axis. Conversely, if the discrepancy along a particular axis is small, light polarized along that axis is scattered to a lesser extent. If the refractive index of the seam along a certain axis substantially coincides with the refractive index of the island, light polarized by an electric field parallel to these axes is not scattered and is birefringent regardless of the size, shape, and density of the birefringent island-in-the-sea yarn part. Will pass through saint-like yarn. Also, if the refractive indices along that axis are substantially coincident, light passes through the object without being substantially scattered.

Figure 3 schematically shows the path of light transmitted through the birefringent island-in-the-sea yarn of the present invention. Referring to FIG. 3, the P wave (solid line) is formed at the birefringent interface between the interface 300 between the outer and the birefringent island-in-the-sea yarns and the interface between the island portion 320a and the sea portion 310a inside the birefringent island-in-the-sea yarn. Although transmitted unaffected, the S wave (dotted line) is transmitted to the birefringent interface between the interface 300 of the substrate and the birefringent island-in-the-sea yarn and / or the interface between the island portion 320a and the sea portion 310a inside the birefringent island-in-the-sea yarn. Under the influence of this, modulation of light occurs.

On the other hand, in the present invention, the refractive index of the island portion and the sea portion of the birefringent island-in-the-sea yarn is preferably 0.03 or less in the difference between the two in the axial direction and 0.05 or more difference in the refractive index in the other one axial direction. In this case, P wave passes through the birefringent interface of birefringent island-in-the-sea yarn, but S wave can cause light modulation. More preferably, the difference in refractive index in the longitudinal direction between the sea portion and the island portion of the birefringent island-in-the-sea yarn is 0.1 or more, and the light modulation efficiency when the refractive indexes of the sea portion and the island portion in the remaining two axial directions substantially coincide. This can be maximized. As a result, in order to maximize the light modulation efficiency of the birefringent 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. To this end, the number of the drawing parts should be large, preferably the number of drawing parts should be 2 to 1,500, and more preferably 500 to 1,500.

As described above, it is preferable that the island portion and sea portion of the birefringent island-in-the-sea yarn have different optical properties, and in particular, the island portion is anisotropic and the sea portion is isotropic. To this end, the island portion and sea portion may be made of different materials. For example, the birefringent island-in-the-sea yarn part may be polyethylene naphthalate, copolyethylene naphthalate, polyethylene terephthalate, polycarbonate, polycarbonate alloy, polystyrene, heat-resistant polystyrene, polymethyl methacrylate, polybutylene terephthalate , Polypropylene, polyethylene, acrylonitrile butadiene styrene, polyurethane, polyimide, polyvinyl chloride, styrene acrylonitrile blend, ethylene vinyl acetate, polyamide, polyacetal, phenol, epoxy, urea, melanin, unsaturated polyester It may be any one or more selected from the group consisting of silicone, elastomer, and cycloolefin polymer, and the sea portion is polyethylene naphthalate, copolyethylene naphthalate, polyethylene terephthalate, polycarbonate, polycarbonate alloy, polystyrene, heat resistant Restyrene, polymethyl methacrylate, polybutylene terephthalate, polypropylene, polyethylene, acrylonitrile butadiene styrene, polyurethane, polyimide, polyvinyl chloride, styrene acrylonitrile mixture, ethylene vinyl acetate, polyamide , Polyacetal, phenol, epoxy, urea, melanin, unsaturated polyester, silicone, elastomer and cycloolefin polymer may be at least one selected from the group consisting of, the island portion and the sea portion preferably has a different refractive index.

The fineness of the birefringent island-in-the-sea yarn of the present invention is preferably 5 to 500 denier. When the birefringent island-in-the-sea yarn has a fineness of less than 5 denier, the number of islands is small, and the light scattering effect by the birefringent island-in-the-sea yarn is too small, and when the fineness exceeds 500 denier, the flexibility of the luminance-enhancing fabric is inferior. Workability becomes low.

The fineness of the island portion of the birefringent island-in-the-sea yarn of the present invention is preferably 0.0001 to 1.0 denier. If the fineness of the island portion is less than 0.0001 denier, it is difficult to maintain the island portion of a constant diameter. If the island portion fineness exceeds 1.0 dea, the area of the optical boundary surface becomes small and the light scattering effect is lowered.

The birefringent island-in-the-sea yarn of the present invention preferably has an area ratio of the sea portion and the island portion of 2: 8 to 8: 2. This is because when the area ratio is in the above range, the area of the interface where light modulation occurs can be effectively ensured.

The non-birefringent yarns of the present invention may be isotropic fibers. This is because non-birefringent yarns do not greatly affect the modulation of light, and thus can reduce manufacturing costs by using simple fibers.

Figure 4 illustrates one embodiment of a group birefringent islands-in-the-sea yarn of the present invention.

The birefringent islands-in-the-sea single yarn of the present invention may be arranged in which the island portions are grouped around two or more spinning cores. Peripheral cores can be arranged.

The grouping of the drawing parts in this way means that when the number of drawing parts is large (about 300 or more), the density of the drawing parts becomes large, and thus, the drawing parts located around the radiating core are agglomerated in the spinning process. This is to prevent. This prevents the excessive accumulation of coating parts in one spinning core and reduces the production cost by forming 500 or more drawing parts in one birefringent island-in-the-sea yarn.

Referring to FIG. 4, two spinning cores 401a and 401b are formed inside the birefringent islands-in-the-sea yarn 400, and the conductive parts 402a and 402b are grouped around the spinning cores 401a and 401b. do. In other words, the concave portions 402a and 402b are partitioned and arranged around the radiating cores 401a and 401b. In this case, the cross-sectional shape of each group of the conductive parts 402a and 402b arranged around the radiating cores 401a and 401b is not limited in kind such as circular, elliptical, polygonal, and deformed cross sections, and the cross-sectional shape of each group is the same. Can be different. For example, in the case where four spinning cores exist inside a birefringent island-in-the-sea yarn, each arrangement of the islands is all quadrangular, but some of the arrangements of the islands are triangular or circular rather than rectangular. May be Meanwhile, in the drawings of the present specification, the radiation core is shown in bold as a black circle, but this is merely an expression for clearly illustrating the radiation core, and means one point that is the center of the actual group. It can be or it can be a solution. Furthermore, the voids inside the birefringent island-in-the-sea yarn may actually be filled with island portions or only sea portions.

Meanwhile, the number of islands arranged in the group-type birefringent island-in-the-sea yarn of the present invention may be 2 to 1,500, and more preferably, the total number of islands may be 500 to 1,500. When adjusted appropriately, most preferably, the number of the entire portion may be 1000 to 1500. Furthermore, 10 to 300 islands may be arranged with respect to the single spinning core, and more preferably, 100 to 150 islands may be arranged, but is not limited thereto. As a result, the number of the islands arranged around the one radiation core described above is birefringent islands-like yarn and the islands of the islands, the microfibers of the desired microfibers, and the optical modulation described below within the range where the abundance of the islands does not occur. It can be adjusted appropriately within the range in which the efficiency can be maximized.

The method for producing the birefringent islands-in-the-sea yarn of the present invention can be applied without any limitation as long as it is a method capable of manufacturing conventional islands-in-the-sea yarns such as a compound 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 fiber contains two or more islands. However, in order to manufacture microfiber yarns, the microfiber yarn is used as a microfiber yarn by eluting the sea portion irrespective of whether it is birefringent or not, but in the present invention, the sea portion and island portion are not eluted. There is a difference in using an island-in-the-sea yarn having different optical properties.

The luminance-enhancing fabric of the present invention may be woven into an asymmetrical structure such that the birefringent island-in-the-sea yarn is more exposed to the surface than the non-birefringent yarn. The surface of the fabric refers to either side of the fabric. The asymmetrical tissue refers to a fabric of a fabric in which the intersection point of the warp and the weft is small, and either the warp or the weft floats on the surface in a long continuous manner. The term intersection refers to staggered positions where the warp and weft are shifted up and down. The luminance-enhancing fabric of this asymmetrical structure can minimize the leaving of the pattern of the fabric (trace of the intersection of the warp and weft) on the luminance-enhanced sheet.

Figure 5a shows a symmetrical fabric. Referring to Figure 5a, the symmetrical fabric of the weft 501 and the warp 502 is woven vertically, the weft 501 is repeatedly positioned at the top and bottom at the intersection with the warp 502. Figure 5b shows an embodiment of the asymmetrical structure of the fabric for brightness enhancement according to the present invention. 5B, the luminance-enhancing fabric of the present invention forms a birefringent island-in-the-sea yarn and a non-birefringent yarn to form a weft 503 and a warp 504 or a warp 504 and a weft 503, respectively. Line A-A 'is a straight line parallel to warp 504 that includes the intersection of weft 503 and warp 504. Looking at the structure of the asymmetrical structure along the line A-A ', one non-birefringent yarn per five birefringent island-like yarns in the direction of the line A-A' is exposed on the surface. Therefore, when weaving the fabric with the asymmetrical structure, the birefringent island-in-the-sea yarn on the surface of the fabric may be more exposed to the surface and the number of intersections may be reduced. In the present invention, such an asymmetric structure is preferably exposed to the surface of one non-birefringent yarn per 5 to 16 birefringent island-in-the-sea yarn in the A-A 'line direction. When one non-birefringent yarn is exposed to the surface per less than five islands in the A-A 'line direction, the number of intersections between the birefringent island-in-the-sea yarn and the non-birefringent yarn is high, and the moiré phenomenon on the LCD screen If one non-birefringent yarn is exposed to the surface of more than 16 birefringent island-in-the-sea yarns in the A-A 'line direction, the hardness of the luminance-enhancing fabric may be low, and defects may occur in bonding operations. .

The asymmetrical structure of the luminance-enhancing fabric of the present invention can be made in various forms. As exemplified above, asymmetrical tissue may be formed by various combinations in addition to one non-birefringent yarn per surface of the birefringent island-in-the-sea yarn in the A-A 'line direction. For example, even if one non-birefringent yarn is exposed to the surface per five birefringent islands in the direction A-A ', the intersection of neighboring non-birefringent yarns is how many wefts are formed. Accordingly, various combinations can be generated. This combination can be limited if the tissue maintains a constant repeating pattern. In other words, the minimum unit repeating vertically, vertically, or horizontally is generally called perfect tissue. When it is determined whether one non-birefringent yarn is exposed to the surface per number of birefringent islands in the direction of line A-A ' The number of cases in the organization is determined accordingly.

The asymmetrical structure of the luminance-enhancing fabric of the present invention may not have a uniform repeating pattern of the tissue. In this case, the asymmetric tissue is preferably exposed to the surface of the birefringent islands-like yarn 5 to 16 times more than the non-birefringent yarn.

The luminance-enhancing fabric of the present invention is preferably birefringent island-in-the-sea yarn of 40 to 240 pieces / inch, non-birefringent yarn is preferably woven 20 to 240 pieces / inch. As described above, when the warp and weft yarns are configured, the light modulation characteristics and the productivity of the luminance-enhancing fabric are excellent.

The birefringent island-in-the-sea yarn constituting the luminance-enhancing fabric of the present invention may be a form in which a plurality of birefringent island-in-the-sea single yarns are plyed together, in which case the birefringent island-in-the-sea single yarn 1 to 200 strands gather to form one birefringent island-in-the-sea yarn. It is preferable that yarn is made.

In this case, the fineness of the birefringent island-in-the-sea single yarn is preferably 0.5 to 30 days. This is because the weaving is easy and the light modulation characteristic is excellent in the above numerical range.

The luminance-enhanced fabric of the present invention is manufactured in the form of a luminance-enhanced sheet and can be applied to various types of optical devices. The luminance-enhanced sheet of the present invention is made by combining the fabric for brightness enhancement to the sheet fabric. Sheet fabric may be made of a variety of materials that can pass light. As a method of combining the fabric for enhancing brightness and the sheet fabric, a vacuum hot press laminating method may be used. In particular, when the brightness enhancing fabric of the present invention is combined with a liquid crystal display device, the brightness of the liquid crystal display device may be increased. The luminance-enhancing fabric of the present invention has the characteristics of passing only light in a specific rotation direction and light modulation characteristics of scattering and reflecting light in other rotation directions and changing rotation, thereby increasing the amount of light supplied to the liquid crystal panel. You can. In addition, the brightness enhancing fabric of the present invention can reduce the moiré phenomenon that may occur on the screen of the liquid crystal display device. The moiré phenomenon refers to a phenomenon in which interference patterns generated by overlapping two or more periodic wave patterns on the screen by the beat phenomenon. Moiré can occur when light passes through a permeable membrane with a regular array of patterns, which can also cause moiré. Therefore, when the luminance-enhanced fabric is woven into an asymmetrical structure as in the present invention, the pattern of the fabric remains in the luminance-enhanced sheet to minimize the occurrence of the moiré phenomenon.

The brightness enhancing sheet of the present invention may be used in other types of flat panel display devices other than the liquid crystal display device to increase the brightness or prevent the moiré phenomenon.

6 is a cross-sectional view of the luminance-enhanced sheet 600 manufactured according to the present invention. As shown, the middle layer is a fabric layer 651 including a birefringent island-in-the-sea yarn, and has a structure in which substrates 652 are stacked on both sides of the fabric. In one embodiment of the present invention, the substrate is preferably an isotropic substrate, the material of the substrate may be the same as the material of the island portion or sea portion of the birefringent islands-like yarn. In addition, the base material mainly uses a polymer film, for example polyethylene naphthalate, copolyethylene naphthalate, polyethylene terephthalate, polycarbonate, polycarbonate alloy, polystyrene, heat-resistant polystyrene, polymethyl methacrylate, polybutylene tere Phthalate, Polypropylene, Polyethylene, Acrylonitrile Butadiene Styrene, Polyurethane, Polyimide, Polyvinylchloride, Styrene Acrylonitrile Mixture, Ethylene Vinyl Acetate, Polyamide, Polyacetal, Phenol, Epoxy, Urea, Melanin, Unsaturated Poly Any one or more selected from the group consisting of esters, silicones, elastomers and cycloolefin polymers can be used.

7 is an exemplary view of a three-dimensional structure formed on the surface of the luminance-enhanced sheet prepared according to the present invention. As can be seen, hemispherical 752a, prismatic 752b, lenticular 752c, and the like are possible.

The method of manufacturing the brightness enhancing sheet according to the present invention will be described in detail with reference to FIGS. 8 and 9.

As illustrated in FIG. 8, the manufacturing method of the present invention is a roll to roll method. The fabric including the island-in-the-sea yarn and the substrate attached to both sides of the fabric are continuously supplied through the unwinding rolls 871, 872, and 873, and the fabric and the substrate thus supplied are interposed between the lamination rolls 874 and 875. Pass it through for lamination continuously.

9 specifically shows the configuration of lamination rolls 974 and 975 used in the roll-to-roll method according to the present invention. As can be seen in the above configuration, the lamination roll includes heating parts 981 and 982 and cooling parts 983 and 984, and the fabric 951 and the substrate 952 are heating parts 981 and 982. The lamination may be performed while passing through, and the state may be fixed while passing through the cooling units 983 and 984 again. In addition, rolls 985 and 986 in which a protective film is attached to both surfaces of the luminance-enhanced sheet 910 passing through the lamination rolls 974 and 975 are added to FIG. 9. At this time, it is preferable to use OPP film or PET film as a protective film.

In the roll lamination apparatus, the temperature of the heating units 981 and 982 is preferably 100 ° C to 300 ° C. If the heating part temperature is less than 100 ° C., the adhesion between the fabric 951 and the substrate 952 may be weakened. If the heating part temperature is higher than 300 ° C., the polymer constituting the island component of island-in-the-sea yarn may be fused to reduce birefringence. Have possession. In addition, the temperature of the cooling unit is preferably 60 ℃ to 180 ℃. If the cooling temperature is less than 60 ℃ is not suitable for the process efficiency, if the cooling temperature exceeds 180 ℃ sufficient cooling is not achieved there is a fear that the deformation of the sheet due to the tension generated during the winding. Moreover, it is preferable that the speed | rate of the said roll is 1 m / min-50 m / min. When the speed of the roll is less than 1 m / min, the process speed is too slow, which is not preferable in terms of process efficiency. When the speed of the roll exceeds 50 m / min, air bubbles are effectively applied in the process of laminating the fabric and the polymer film. It can be difficult to remove and insufficient adhesion.

When the brightness enhancement sheet manufactured according to the present invention is bonded to the LCD panel, it is possible to increase the brightness of the LCD. The luminance-enhanced sheet of the present invention has the characteristics of passing only light in a specific rotation direction and scattering and reflecting light in other rotation directions and changing rotation, thereby increasing the amount of light supplied to the panel. . In other words, in the LCD panel, only the light of a certain rotation can pass through the luminance-enhancing panel. In the LCD panel, the birefringent island-in-the-sea yarn of the luminance-enhancing fabric scatters light that does not pass through the panel and changes the rotation direction. To make it pass through the panel.

As described above, weaving the fabric used in the luminance-enhanced sheet according to the present invention into satin tissue can reduce the moiré phenomenon that may occur on the LCD screen. The moiré phenomenon refers to a phenomenon in which interference patterns generated by overlapping two or more periodic wave patterns on the screen by the beat phenomenon. Moiré can occur when light passes through a permeable membrane with a regular array of patterns, which can also cause moiré. Therefore, when the fabric containing the birefringent island-in-the-sea yarn as in the present invention is woven into an asymmetrical structure, the pattern of the fabric remains in the luminance-reinforced sheet to minimize the occurrence of the moiré phenomenon.

Hereinafter, the present invention will be described in more detail using examples and comparative examples.

<Example 1>

Isotropic PC alloy (nx = 1.55, ny = 1.55, nz = 1.55) containing 5: 5 of polycarbonate and modified glycol polycyclohexylene dimethylene terephthalate (PCTG) as a sea component and anisotropic PEN (nx = 1.88, ny = 1.57, nz = 1.57) were formed into the drawing parts, and 200 drawing parts were arranged. Through this composition, the unstretched yarn is 150/24, and the spinning temperature is 305 ° C. and the spinning speed is 1500 M / min. The yarn is then tripled to prepare birefringent island-in-the-sea yarn of the stretched yarn 50/24 It was. The woven fabric was woven with the prepared island-in-the-sea yarn as the weft yarn and the isotropic PC alloy fibers as the warp yarns. At this time, the fabric was woven into an asymmetrical structure, and one non-birefringent yarn per six birefringent island-in-the-sea yarns were exposed on the surface in the direction of progress of the non-birefringent yarn. Then, the woven fabric is placed on an unwinding roll located in the center of the roll-to-roll laminator, and the PC alloy sheet (having the same composition and optical properties as that of the birefringent island-in-the-sea yarn) is placed on top of the fabric unwinding roll. It was placed on the two unwinding rolls at the bottom. Thereafter, the fabric and two PC alloy sheets (substrate) were simultaneously introduced into an extrusion roll to apply heat and pressure. At this time, the temperature of the roll was 200 ℃, the pressure was 25kgf / cm2, the processing speed was applied to the condition of 5 MPM. As a result, a luminance-reinforced sheet having a thickness of 400 μm was manufactured.

<Example 2>

The brightness-reinforcing sheet was manufactured in the same manner as in Example 1 except that the weaving method of the fabric was such that one non-birefringent yarn per ten birefringent island-in-the-sea yarns were exposed to the surface in the advancing direction of the non-birefringent yarn. .

<Example 3>

The brightness-reinforcing sheet was manufactured in the same manner as in Example 1 except that the weaving method of the fabric was such that one non-birefringent yarn per 15 birefringent island-in-the-sea yarns were exposed to the surface in the advancing direction of the non-birefringent yarn. .

Comparative Example 1

The luminance-enhanced sheet was carried out in the same manner as in Example 1, except that an isotropic island-in-the-sea yarn having an isotropic PET (nx = ny = nz = 1.57) and an isotropic C0-PEN (nx = ny = nz = 1.57) portion was used. Was prepared.

Comparative Example 2

The brightness-enhanced sheet was manufactured in the same manner as in Example 1 except that the weaving method of the fabric was exposed to one surface per two weft yarns in the direction of the warp.

Comparative Example 3

Except that the woven fabric in a symmetrical structure was prepared in the same manner as in Example 1 luminance-reinforced sheet.

Experimental Example

Table 1 shows the results of evaluating the following physical properties of the luminance-enhanced sheet manufactured by the above Examples and Comparative Examples.

1. Luminance

Insert a brightness enhancing sheet manufactured according to the above embodiments and comparative examples between the 32 "liquid crystal panel and the direct backlight unit, and measure the average of nine points using a BM-7 measuring instrument manufactured by Topcon. Indicated.

2. Transmittance

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

3. Polarization degree

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

4. Moire test

The panel was assembled on a 32 "direct backlight unit equipped with a diffuser plate, two diffuser sheets, and a brightness enhancing film, and then visually discriminated into four levels of weak, weak, medium, and steel.

Luminance (cd / ㎡) Transmittance (%) % Polarization Moire Example 1 400 52 78 weak Example 2 400 52 78 weak Example 3 400 52 78 weak Comparative Example 1 270 85 2 weak Comparative Example 2 400 52 78 medium Comparative Example 3 400 52 78 River

As can be seen in Table 1, the liquid crystal display device (Examples 1 to 3) to which the luminance-enhancing fabric containing the birefringent island-in-the-sea yarn of the present invention is applied (Examples 1 to 3) does not apply the liquid crystal display device (Comparative Examples 1 to 1) Compared to Example 3) the overall optical properties were excellent. Specifically, when birefringent islands-in-the-sea yarns having different optical characteristics of the island portion and the sea portion are used (Examples 1 to 3, Comparative Example 2 and Comparative Example 3), the optical characteristics of the island portion and the sea portion are the same ( The luminance was higher than that of Comparative Example 1). As a result of evaluating the brightness enhancing sheet itself, Comparative Example 1 had a lower polarization degree and a higher transmittance than Comparative Examples 1 to 3, Comparative Example 2 and Comparative Example 3, In the case of Examples 1 to 3, Comparative Example 2 and Comparative Example 3 having a light modulation function was higher than Comparative Example 1. On the other hand, when the fabric was woven into a symmetrical structure (Comparative Example 3) and when one warp per two wefts were exposed to the surface in the direction of the warp (Comparative Example 2), the moiré phenomenon was observed to be strong and medium, respectively. In Examples 1 to 3 and Comparative Example 1, the moiré phenomenon was observed to be weak.

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

2 is a cross-sectional view of the birefringent islands-in-the-sea yarn of the present invention.

Figure 3 schematically shows the path of light transmitted through the birefringent island-in-the-sea yarn of the present invention.

4 is a cross-sectional view of an embodiment of a group birefringent islands-in-the-sea yarn according to the present invention.

Figures 5a and 5b shows a fabric of symmetrical and asymmetrical tissue in accordance with an embodiment of the present invention.

6 is a cross-sectional view of the luminance-enhanced sheet manufactured according to an embodiment of the present invention.

7 is an exemplary view of a three-dimensional structure formed on the surface of the luminance-enhanced sheet prepared according to the present invention.

8 is a view showing a roll-to-roll apparatus according to an embodiment of the present invention.

9 is a view showing a roll-to-roll apparatus according to another embodiment of the present invention.

<Description of the symbols for the main parts of the drawings>

871, 872, 873: unwinding rolls 874, 875, 974, 975: lamination rolls

910: brightness enhancement sheet 951: fabric

952: polymer film 981, 982: heating part

983, 984: cooling section

Claims (35)

A method of manufacturing a luminance-reinforced sheet comprising a fabric including a birefringent island-in-the-sea yarn and a substrate, the method comprising: passing the fabric and the substrate through a lamination roll to form a sheet on which a substrate is laminated on a fabric including a birefringent island-in-the-sea yarn Method for producing a brightness enhancement sheet, characterized in that. The method of claim 1, wherein the substrate is laminated on both sides of the fabric. The method of claim 1, wherein the fabric and the substrate are respectively supplied to a lamination roll through an unwinding roll. The method of claim 1, wherein the lamination roll comprises a heating unit and a cooling unit. 5. The method of claim 4, wherein the heating unit has a temperature of 100 ° C to 300 ° C. The method of claim 4, wherein the cooling unit has a temperature of 60 ° C. to 180 ° C. 6. The method of claim 1, wherein the roll has a speed of 1 to 50 m / min. The method of claim 1, further comprising forming a three-dimensionally structured pattern on the surface of the luminance-enhanced sheet. The method of claim 8, wherein the three-dimensionally structured pattern is selected from a hemispherical, prismatic, or lenticular pattern formed repeatedly. The method of claim 1, wherein the fabric is one of warp and weft yarns using a birefringent island-in-the-sea yarn and the other is a non-birefringent yarn. The method according to claim 10, wherein the birefringent island-in-the-sea yarn is woven into an asymmetrical structure so as to be exposed to the surface more than the non-birefringent yarn. 12. The method of claim 11, wherein the asymmetrical structure is exposed to the surface of one non-birefringent yarn per 5 to 16 birefringent islands-in-the-sea yarn in the direction of travel of the non-birefringent yarn. . 12. The method of claim 11, wherein the asymmetrical structure is exposed to the surface of the birefringent island-in-the-sea yarn 5 to 16 times more than the non-birefringent yarn. 12. The method of claim 11, wherein the birefringent island-in-the-sea yarn is 100 to 240 pieces / inch, and the non-birefringent yarn is woven to 20 to 240 pieces / inch. The method of claim 10, wherein the birefringent islands-in-the-sea yarn comprises 1 to 200 strands of birefringent islands-in-the-sea single yarn. 11. The method of claim 10, wherein the birefringent island-in-the-sea yarn has a fineness of 5 to 500 denier. 16. The method according to claim 15, wherein the fineness of the birefringent island-in-the-sea single yarn is 0.5 to 30 denier. 11. The method of claim 10, wherein the birefringent island-in-the-sea yarn has a drawing portion of 2 to 1500. 11. The method of claim 10, wherein the fineness of the island portion of the birefringent island-in-the-sea yarn is 0.001 to 1.0 denier. The method of claim 10, wherein the non-birefringent yarn is an isotropic fiber. The method of manufacturing a brightness-enhanced sheet according to claim 10, wherein the optical properties of the island portion and the sea portion of the birefringent island-in-the-sea yarn are different. 22. The method of claim 21, wherein the island portion is anisotropic and the sea portion is isotropic. The birefringent island-in-the-sea yarn of claim 10 is polyethylene naphthalate, copolyethylene naphthalate, polyethylene terephthalate, polycarbonate, polycarbonate alloy, polystyrene, heat resistant polystyrene, polymethylmethacrylate, polybutyl Lenterephthalate, polypropylene, polyethylene, acrylonitrile butadiene styrene, polyurethane, polyimide, polyvinylchloride, styrene acrylonitrile mixture, ethylene vinyl acetate, polyamide, polyacetal, phenol, epoxy, urea, Method for producing a luminance-enhanced sheet, characterized in that any one or more selected from the group consisting of melanin, unsaturated polyester, silicone, elastomer and cycloolefin polymer. 11. The method of claim 10, wherein the birefringent island-in-sea yarn seabed is polyethylene naphthalate, copolyethylene naphthalate, polyethylene terephthalate, polycarbonate, polycarbonate alloy, polystyrene, heat-resistant polystyrene, polymethyl methacrylate, polybutyl Lenterephthalate, polypropylene, polyethylene, acrylonitrile butadiene styrene, polyurethane, polyimide, polyvinylchloride, styrene acrylonitrile blend, ethylene vinyl acetate, polyamide, polyacetal, phenol, epoxy, urea, melanin, Method for producing a luminance-enhanced sheet, characterized in that any one or more selected from the group consisting of unsaturated polyesters, silicones, elastomers and cycloolefin polymers. The refractive index of the birefringent islands-in-the-sea yarn and the island portion of the birefringent island-like yarn is 0.03 or less in the difference in refractive index in two axial directions, and the difference in the refractive index in the one axial direction is 0.05 or more. Method of manufacturing a brightness enhancement sheet. The method of claim 10, wherein the area ratio of the sea portion and the island portion of the birefringent island-in-the-sea yarn is 2: 8 to 8: 2. The method of claim 10, wherein the birefringent island-in-the-sea yarn has a drawing portion arranged in groups of two or more spinning cores. 28. The method of claim 27, wherein the radiation core has one radiation reference core at a center thereof and a plurality of radiation peripheral cores are arranged at the center thereof. The method of claim 1, wherein the substrate is an isotropic substrate. The method of claim 1, wherein the base material is the same as the material of the island portion or sea portion of the birefringent island-in-the-sea yarn. The method of claim 1, wherein the substrate is a substrate. The method of claim 1, wherein the substrate is polyethylene naphthalate, copolyethylene naphthalate, polyethylene terephthalate, polycarbonate, polycarbonate alloy, polystyrene, heat-resistant polystyrene, polymethyl methacrylate, polybutylene terephthalate, poly Propylene, polyethylene, acrylonitrile butadiene styrene, polyurethane, polyimide, polyvinyl chloride, styrene acrylonitrile mixture, ethylene vinyl acetate, polyamide, polyacetal, phenol, epoxy, urea, melanin, unsaturated polyester, silicone Method for producing a luminance-enhanced sheet, characterized in that any one or more selected from the group consisting of an elastomer and a cycloolefin polymer. The method of claim 1, further comprising attaching a protective film to both surfaces of the luminance-enhanced sheet manufactured by passing through the lamination roll. 34. A luminance-enhanced sheet characterized in that it is manufactured by the manufacturing method according to any one of claims 1 to 33. A liquid crystal display device comprising the brightness enhancing sheet of claim 34.

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