WO2013100664A1

WO2013100664A1 - Method and apparatus for manufacturing multilayer reflective polarizer

Info

Publication number: WO2013100664A1
Application number: PCT/KR2012/011635
Authority: WO
Inventors: 조덕재; 한정완; 백명기; 고승진; 이황규
Original assignee: 웅진케미칼 주식회사
Priority date: 2011-12-28
Filing date: 2012-12-27
Publication date: 2013-07-04
Also published as: TWI509298B; TW201333555A

Abstract

A method for manufacturing a reflective polarizer according to the present invention produces a plurality of multilayer combined flows having different mean optical widths by means of a plurality of slit-type extrusion dies, and combines same while in molten states, thereby obviating a separate adhesion layer and/or a protective boundary layer (PBL) in the interior of a core layer, and allowing all S waves in the visible wavelength range to be reflected. Also, formation of a skin layer, on at least one surface of a core layer, while in a molten state obviates a separate adhesion step. Thus, manufacturing costs may be significantly reduced, and optical properties can be favorably maximized within the restricted widths.

Description

Method and apparatus for manufacturing multilayer reflective polarizer

The present invention relates to a method and apparatus for manufacturing a multilayer reflective polarizer, and more particularly, to a core layer including a plurality of groups having different average optical thicknesses within the core layer and not forming an adhesive layer between the groups, and integrally with the core layer. The present invention provides a method and apparatus for manufacturing a multilayer reflective polarizer including a formed skin layer.

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. LCD displays are currently expanding their range of use, including notebooks, personal computer monitors, LCD TVs, automobiles, and airplanes, accounting for about 80% of the flat panel market, and are booming to date due to a sharp increase in LCD demand worldwide.

Conventional liquid crystal displays arrange a liquid crystal and an electrode matrix between a pair of light absorbing optical films. In a liquid crystal 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, liquid crystal displays include a front optical film and a back optical film that induce polarization.

The optical film used in such a liquid crystal display does not necessarily have high utilization efficiency of light emitted from the backlight. This is because 50% or more of the light emitted from the backlight is absorbed by the back side optical film (absorption type polarizing film). Thus, in order to increase the utilization efficiency of backlight light in the liquid crystal display, a reflective polarizer is provided between the optical cavity and the liquid crystal assembly.

1 is a view showing the optical principle of a conventional reflective polarizer. Specifically, P-polarized light from the optical cavity to the liquid crystal assembly passes through the reflective polarizer to the liquid crystal assembly, and S-polarized light is reflected from the reflective polarizer 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 then transmitted back to the reflective polarizer so that S-polarized light is converted into P-polarized light which can pass through the polarizer of the liquid crystal assembly, and then passed through the reflective polarizer to be transmitted 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 reflective polarizer are based on the refractive index of each optical layer 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 laminated alternately. 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 to the reflective polarizer 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 polarized light 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 reflective polarizer again. As a result, power loss can be reduced together with the loss of light generated from the light source.

However, the conventional reflective polarizer has an optical thickness and a refractive index between the optical layers that can be optimized for selective reflection and transmission of incident polarization by alternately stacking isotropic optical layers and anisotropic optical layers having different refractive indices. Since it is manufactured so as to have it, there existed a problem that the manufacturing process of a reflective polarizer was complicated. In particular, since each optical layer of the reflective polarizer has a flat plate structure, it is necessary to separate P-polarized light and S-polarized light in response to a wide range of incident angles of incident polarization, so that the number of optical layers is excessively increased and the production cost is exponentially increased. 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.

2 is a cross-sectional view of a conventional multilayer reflective polarizer (DBEF). Specifically, the multilayer reflective polarizer has

skin layers

9 and 10 formed on both surfaces of the core layer 8. The core layer 8 is divided into four groups (1, 2, 3, 4), each group having an isotropic layer and an anisotropic layer alternately stacked to form approximately 200 layers. On the other hand, between the four groups (1, 2, 3, 4) forming the core layer (8) is formed a separate adhesive layer (5, 6, 7) for bonding them. In addition, since each group has a very thin thickness of about 200 layers, each group may be damaged when co-extrusion of these groups individually, so the groups often include a protective layer (PBL). In this case, there is a problem that the thickness of the core layer becomes thick and the manufacturing cost increases. In addition, since the reflective polarizer included in the display panel has a limitation on the thickness of the core layer for slimming, when the adhesive layer is formed on the core layer and / or the skin layer, the core layer is reduced by the thickness thereof, which is very good for improving optical properties. There was no problem. Furthermore, since the inside of the core layer and the core layer and the skin layer are bonded by an adhesive layer, there is a problem in that an interlayer peeling phenomenon occurs when an external force is applied, when a long time passes, or when the storage location is poor. In addition, in the process of attaching the adhesive layer, not only the defect rate is excessively high but also there is a problem in that offset interference with the light source occurs due to the formation of the adhesive layer.

Skin layers

9 and 10 are formed on both sides of the core layer 8, and separate

adhesive layers

11 and 12 are formed to couple them between the core layer 8 and the

skin layers

9 and 10. do. In case of integrating the conventional polycarbonate skin layer and PEN-coPEN by alternatingly laminated core layer through co-extrusion, peeling may occur due to incompatibility, and the crystallization degree is about 15%. There is a high risk of birefringence. Accordingly, in order to apply the polycarbonate sheet of the non-stretching process, there was no choice but to form an adhesive layer. As a result, the addition of the adhesive layer process results in a decrease in yield due to external foreign matters and process defects. In general, when the polycarbonate non-stretched sheet of the skin layer is produced, birefringence occurs due to uneven shear pressure due to the winding process. In order to compensate, a separate control such as deformation of the polymer molecular structure and speed control of the extrusion line were required, resulting in a decrease in productivity.

Briefly describing the conventional method of manufacturing a multilayer reflective polarizer, after co-extracting four groups having different average optical thicknesses for forming the core layer separately, the four co-extruded groups are stretched and then stretched. The four groups were glued together to form a core layer. This is because peeling phenomenon occurs when the core layer is stretched after adhesive bonding. Thereafter, the skin layer is adhered to both surfaces of the core layer. After all, to make a multi-layer structure, by folding the two-layer structure to form a four-layer structure, and by forming a multi-layer structure of a continuous folding method to form a group (209 layers) and co-extruded it can not give a change in thickness one process It was difficult to form groups inside the multilayer at. As a result, four groups having different average optical thicknesses can be co-extruded separately and then bonded to each other.

Since the above-described process is performed intermittently, the production cost has been increased, and as a result, there is a problem that the cost is the most expensive among all the optical films included in the backlight unit. Accordingly, there has been a serious problem in that a liquid crystal display is often released except for a reflective polarizer even though the luminance decrease in terms of cost reduction.

Accordingly, a reflective polarizer in which a polymer is dispersed, which can achieve the function of the reflective polarizer by arranging the birefringent polymer elongated in the longitudinal direction inside the substrate rather than the multilayer reflective polarizer, has been proposed. 3 is a perspective view of a reflective polarizer 20 including a rod-shaped polymer, in which the birefringent polymer 22 extending in the longitudinal direction is arranged in one direction in the substrate 21. Through this, the birefringent interface between the substrate 21 and the birefringent polymer 22 causes the light modulation effect to perform the function of the reflective polarizer. However, as compared with the above-described alternately stacked reflective polarizers, it is difficult to reflect light in the entire visible light wavelength region, resulting in a problem that the light modulation efficiency is too low. Thus, in order to have a transmittance and reflectance similar to that of the alternating reflective polarizers, there is a problem in that a large number of birefringent polymers 22 must be disposed inside the substrate. Specifically, in the case of manufacturing a horizontal 32-inch display panel based on the vertical cross section of the reflective polarizer, in order to have optical properties similar to those of the stacked reflective polarizer described above in the substrate 21 having a width of 1580 mm and a height (thickness) of 400 μm or less, At least 100 million circular or elliptical birefringent polymers 22 having a cross-sectional diameter in the longitudinal direction of 0.1 to 0.3 μm should be included. In this case, not only the production cost is excessively high, but also the equipment becomes too complicated and There was a problem that it is difficult to commercialize the facility itself is almost impossible. In addition, since the optical thickness of the birefringent polymer 22 included in the sheet is difficult to be configured in various ways, it is difficult to reflect the light in the entire visible light region, thereby reducing the physical properties.

In order to overcome this problem, a technical idea including a birefringent island-in-the-sea yarn has been proposed. FIG. 4 is a cross-sectional view of a birefringent island-in-the-sea yarn included in the substrate, and the birefringent island-in-the-sea yarn may generate a light modulation effect at an optical modulation interface between the inner and sea portions of the inner portion, and thus, a very large number such as the birefringent polymer described above. Optical properties can be achieved even if the island-in-the-sea yarns are not disposed. However, since the birefringent island-in-the-sea yarn is a fiber, problems of compatibility, ease of handling, and adhesion with a substrate which is a polymer have arisen. Furthermore, due to the circular shape, light scattering is induced, and thus the reflection polarization efficiency of the visible wavelength is reduced, and the polarization characteristic is lowered compared to the existing products, thereby limiting the luminance improvement. As the area is subdivided, the voids cause the optical leakage due to light leakage, that is, light loss. In addition, there is a problem that a limitation occurs in the reflection and polarization characteristics due to the limitation of the layer configuration due to the organization of tissue in the form of a fabric.

The present invention relates to a method and apparatus for manufacturing a multilayer reflective polarizer, and more particularly, to a method for manufacturing a multilayer reflective polarizer including a core layer formed of a plurality of groups having different average optical thicknesses and a skin layer formed simultaneously with the core layer. To provide a device.

A method for manufacturing a multilayer reflective polarizer of the present invention for achieving the above object of the present invention is a method of manufacturing a multilayer reflective polarizer comprising a core layer of the first component and the second component alternately laminated, (1) the first Supplying the component and the second component to the extruders, respectively; (2) forming two or more multilayered composites in which the repeating units of the first component and the second component are alternately laminated, wherein each of the multilayered composites reflects a shear wave (S wave) of a desired wavelength; Injecting the first component and the second component transferred from the plurality of slit-type extrusion molds to form two or more multilayered composites having different average optical thicknesses of the repeating units; (3) laminating the two or more multilayered composites into one to form a core layer; And (4) inducing spreading of the core layer in the flow control unit.

According to a preferred embodiment of the present invention, in the case of supplying the skin layer component to the extruder in step (1) between the step (3) and (4) extruded on at least one surface of the core layer formed in step (3) The method may further include laminating the skin layer component transferred from the unit.

According to another preferred embodiment of the present invention, when the skin layer component is supplied to the extruder in step (1), the skin layer component transferred from the extruder may be laminated on at least one surface of the core layer in step (3). have.

According to still another preferred embodiment of the present invention, in the apparatus for manufacturing a multilayer reflective polarizer including a core layer in which a first component and a second component are alternately laminated, a first component and a second component are separately added. Two or more extrusion parts; The repeating unit of the first component and the second component forms two or more multilayered composite flows in which the laminated units are alternately stacked, and each of the multilayer composite flows is transferred from the extruder to reflect the shear wave (S wave) of a desired wavelength. A spin block portion including a slit-type extrusion block for inputting a first component and a second component to produce two or more multilayered composites having different average optical thicknesses of repeating units; A collection block unit for laminating the two or more multi-layer composite streams transferred from the spin block unit to one to form a core layer; And a flow control unit for inducing the spread of the core layer transferred from the collection block unit.

According to another preferred embodiment of the present invention, when the extruder comprises an extruder in which the skin layer components are separately injected, the multi-layered composites communicated with the extruder into which the skin layer components are injected and transferred from the spin block unit. The at least one surface may further include a feed block unit for laminating the skin layer.

According to another preferred embodiment of the present invention, when the extruder includes an extruded portion into which the skin layer component is separately injected, at least one surface of the core layer formed in communication with the extruder into which the skin layer component is injected and the collection block portion The skin layer can be laminated.

According to another preferred embodiment of the present invention, the spin block portion discharges the first component conveyed from the extruded portion and the first pressing means for supplying to the island-in-the-sea extrusion mold and the second component conveyed from the extruded portion It may include a second pressing means for discharging to supply to the island-in-the-sea extrusion mold.

In the manufacturing method of the present invention, a plurality of multi-layered composites having different average optical thicknesses are manufactured using a plurality of slit-type extrusion molds and laminated in a molten state, so that a separate adhesive layer and / or protective layer (PBL) is formed inside the core layer. It can reflect all the S-waves in the visible wavelength range without the need. In addition, the skin layer is also formed on at least one surface of the core layer in the molten state, and does not go through a separate bonding step. This not only significantly reduces the manufacturing cost but is also very advantageous in maximizing optical properties at a limited thickness.

1 is a schematic diagram illustrating the principle of a conventional reflective polarizer.

2 is a cross-sectional view of a multilayer reflective polarizer (DBEF) currently in use.

3 is a perspective view of a reflective polarizer comprising a rod-shaped polymer.

4 is a cross-sectional view showing a path of light incident on a birefringent island-in-the-sea yarn used in a reflective polarizer.

Figure 5 is a perspective view of the distribution plate of the slit-shaped extrusion mold that can be used in the present invention, Figure 6 is a bottom view of them, Figure 7 is a bond.

8 is a cross-sectional view of a multilayer composite according to a preferred embodiment of the present invention.

9 is a schematic diagram comprising two first press means to form two multi-layered composite flows in accordance with a preferred embodiment of the present invention.

10 is a schematic diagram comprising two second pressurizing means to form two multi-layered composite flows in accordance with a preferred embodiment of the present invention.

Figure 11 is a schematic diagram showing the lamination of the multi-layered composites and skin layer according to an embodiment of the present invention.

12 is a cross-sectional view of a coat-hanger die in accordance with a preferred embodiment of the present invention, and FIG. 13 is a side view.

14 is a cross-sectional view of a multilayer reflective polarizer in accordance with a preferred embodiment of the present invention.

15 is a cross-sectional view of a multilayer reflective polarizer according to another exemplary embodiment of the present invention.

16 is a cross-sectional view of a multilayer reflective polarizer according to another preferred embodiment of the present invention.

17 is a schematic diagram of an apparatus for manufacturing a multilayer reflective polarizer according to a preferred embodiment of the present invention.

18 is a schematic diagram of an apparatus for manufacturing a multilayer reflective polarizer according to another preferred embodiment of the present invention.

19 is a schematic diagram of an apparatus for manufacturing a multilayer reflective polarizer according to another preferred embodiment of the present invention.

20 is an exploded perspective view of a liquid crystal display device including the reflective polarizer of the present invention.

Hereinafter, with reference to the accompanying drawings the present invention will be described in more detail.

CLAIMS What is claimed is: 1. A method of manufacturing a multilayer reflective polarizer comprising a core layer of alternating first and second components, the method comprising: (1) supplying first and second components to the extruders, respectively; (2) forming two or more multilayered composites in which the repeating units of the first component and the second component are alternately laminated, wherein each of the multilayered composites reflects a shear wave (S wave) of a desired wavelength; Injecting the first component and the second component transferred from the plurality of slit-type extrusion molds to form two or more multilayered composites having different average optical thicknesses of the repeating units; (3) laminating the two or more multilayered composites into one to form a core layer; And (4) inducing spreading of the core layer in the flow control unit.

First, as step (1), the first component, the second component and the skin layer component are respectively supplied to the extruded parts. If only the core layer is present, the skin layer component is omitted. The first component may be any polymer as long as it is used in a reflective polarizer in which a conventional polymer is dispersed as a polymer dispersed in the second component forming a substrate, and preferably, polyethylene naphthalate (PEN), copolyethylene, Phthalate (co-PEN), Polyethylene terephthalate (PET), Polycarbonate (PC), Polycarbonate (PC) alloy, Polystyrene (PS), Heat-resistant polystyrene (PS), Polymethylmethacrylate (PMMA), Polybutyl Rent Terephthalate (PBT), Polypropylene (PP), Polyethylene (PE), Acrylonitrile Butadiene Styrene (ABS), Polyurethane (PU), Polyimide (PI), Polyvinyl Chloride (PVC), Styrene Acrylic Nitrile Blend (SAN), Ethylene Vinyl Acetate (EVA), Polyamide (PA), Polyacetal (POM), Phenolic, Epoxy (EP), Urea (UF), Melanin (MF), Unsaturated Polyester (UP), Silicone (SI) and cycloolefin polymers are used Number and may be more preferably PEN.

The second component may be used without limitation as long as the second component is used as a material of the substrate in the reflective polarizer in which the polymer is dispersed. Preferably, the polyethylene naphthalate (PEN) and the copolyethylene naphthalate (co-PEN) are used. ), Polyethylene terephthalate (PET), polycarbonate (PC), polycarbonate (PC) alloy, polystyrene (PS), heat-resistant polystyrene (PS), polymethyl methacrylate (PMMA), polybutylene terephthalate (PBT) ), Polypropylene (PP), polyethylene (PE), acrylonitrile butadiene styrene (ABS), polyurethane (PU), polyimide (PI), polyvinyl chloride (PVC), styrene acrylonitrile mixture (SAN) Ethylene vinyl acetate (EVA), polyamide (PA), polyacetal (POM), phenol, epoxy (EP), urea (UF), melanin (MF), unsaturated polyester (UP), silicone (SI) and cyclic Alone or mixed with a low-olefin polymer Can be used and may be more preferably, dimethyl 2,6-naphthalenedicarboxylate, dimethyl terephthalate and ethylene glycol, Im chroman-hexane dimethanol (CHDM), such as the monomers are suitably polymerized co-PEN.

The skin layer component may be used without limitation as long as it is typically used in a reflective polarizer in which a polymer is dispersed. Preferably, polyethylene terephthalate (PET), polycarbonate (PC), polycarbonate (PC) alloy, and polystyrene (PS) are used. ), Heat-resistant polystyrene (PS), polymethyl methacrylate (PMMA), polybutylene terephthalate (PBT), polypropylene (PP), polyethylene (PE), acrylonitrile butadiene styrene (ABS), polyurethane (PU) ), Polyimide (PI), polyvinyl chloride (PVC), styrene acrylonitrile mixture (SAN), ethylene vinyl acetate (EVA), polyamide (PA), polyacetal (POM), phenol, epoxy (EP) , Urea (UF), melanin (MF), unsaturated polyester (UP), silicone (SI) and cycloolefin polymers can be used. The polycarbonate alloy is preferably made of polycarbonate and modified glycol polycyclohexylene dimethylene terephthalate (PCTG), more preferably polycarbonate and modified glycol polycyclohex The silane dimethylene terephthalate (PCTG) may be a polycarbonate alloy having a weight ratio of 15:85 to 85:15. Meanwhile, the skin layer of the present invention preferably uses a material having a small change in refractive index in spreading and stretching processes, and more preferably, may be polycarbonate or polycarbonate alloy.

On the other hand, the first component, the second component and the skin layer component can be supplied separately to the independent extrusion parts, in this case, the extrusion part may be composed of three or more. Also included in the present invention is a feed to one extruder comprising a separate feed passage and distributor so that the polymers do not mix. The extruder may be an extruder, which may further include heating means or the like to convert the supplied polymers into a liquid phase.

Next, in step (2), two or more multilayer composite flows in which the repeating units of the first component and the second component are alternately laminated are formed, and each of the multilayer composite flows reflects the shear wave (S wave) of a desired wavelength. The first component and the second component transferred from the extruder are introduced into a plurality of slit-type extrusion slots to form two or more multi-layered composite flows having different average optical thicknesses of the repeating units.

Specifically, FIGS. 5 to 7 are perspective views, bottom views, and coupling views of the distribution plates of the slit-type extrusion mold that may be used in the present invention. It is a perspective view which shows the coupling structure of the distribution board of a slit-type extrusion mold. The first mold distribution plate S1 positioned at the upper end of the slit-type extrusion mold may be composed of a first component supply passage 50 and a second component supply passage 51 therein. Through this, the first component transferred through the extruder may be introduced into the first component supply path 50, and the second component may be supplied to the second supply path 51. In some cases, a plurality of such supply paths may be formed. The polymers that have passed through the first mold distribution plate S1 are transferred to a second mold distribution plate S2 positioned below. The first component introduced through the first component supply path 50 is branched and transferred to the plurality of first

component supply paths

52 and 53 along the flow path. In addition, the second component introduced through the second component supply passage 51 is branched and transferred to the plurality of second

component supply passages

54, 55, 56 along the flow path. The polymers that have passed through the second detention distribution plate S2 are transferred to the third detention distribution plate S3 located below.

The first components introduced through the first

component supply paths

52 and 53 are first

component supply paths

60, 61, 62, 63, 67, 68, 69, respectively formed in the third detention distribution plate S3. And branched along the flow path. Similarly, the second components introduced through the second

component supply paths

54, 55, and 56 are second

component supply paths

57, 58, 59, 64, 65, and 66 formed in the third detention distribution plate S3, respectively. , 71, 72, 73 are branched along the flow path. Thereafter, the first component introduced through some of the first

component supply paths

60 and 67 among the first component supply paths formed in the third prison distribution plate S3 is flow paths formed in the fourth prison distribution plate S4. The first flow path 74 of the. Similarly, the first component introduced through some of the second component supply paths 57, 64, and 71 among the second component supply paths formed in the third prison distribution plate S3 is a flow path formed in the fourth prison distribution plate S4. Is transferred to the second flow path 75. In this manner, the first component conveyed through the first component supply paths of the third prison distribution plate S3 is distributed to the odd-numbered

flow paths

74, 76, 78, 80 of the fourth prison distribution plate S4. The second component transferred through the second component supply paths of the third prison distribution plate S3 is transferred to the even-numbered

flow paths

75, 77, 79 of the fourth prison distribution plate S4. As a result, the first component and the second component may be alternately stacked. In this way, a lower portion of the fourth detention distribution plate S4 may further include a detention distribution plate (not shown) which is perpendicular to the flow direction of the fourth detention distribution plate and has a larger number of flow passages, and repeats the desired layer. It would be apparent to one skilled in the art to extend the number of flow paths by a number. On the other hand, the first component transferred through the odd-numbered

flow paths

74, 76, 78, and 80 of the fourth detention distribution plate S4 on the same principle is the odd-numbered flow paths 81, of the fifth detention distribution plate S5. 83, 85, 87, 89, 91, and 93, and the second component transferred through the even-numbered

flow paths

75, 77, and 79 of the fourth detention distribution plate S4 includes a fifth detention distribution plate ( The even-numbered

flow paths

82, 84, 86, 88, 90, 91, and 92 of S5) are transferred. FIG. 6 is a bottom view of the slit-type extrusion mold of FIG. 5, and the discharge path of the fifth mold distribution plate S5 is integrally formed with the slit type, not spaced apart from the hole type. As a result, the first component and the second component form respective layers. Therefore, the number of layers of the multilayer composite stream may be determined according to the number of slits of the fifth mold distribution plate S5. The preferred number of layers may be at least 100, more preferably at least 150, even more preferably at least 200 and most preferably at least 300. Thereafter, the multi-layered composite stream is discharged through the discharge port 94 of the sixth mold distribution plate. 8 is a cross-sectional view of a multi-layered composite, in which the

first components

100 and 102 and the

second components

101 and 103 are alternately stacked. At this time, one first component 100 and the stacked second component 101 may be defined as a repeating unit, and one complex flow includes a plurality of repeating units.

By the way, Figures 5 to 7 are examples of the detention distribution plate that can be used in the slit-type extrusion mold that can be used of the present invention, the detention distribution plate to produce a multilayer composite flow of the first component and the second component alternately laminated It will be apparent to those skilled in the art that the number, structure, size of the hole, size, shape, slit size of the fifth mold distribution plate, size of the discharge hole, etc. are properly designed and used by those skilled in the art. On the other hand, the diameter of the slits in the bottom view of the fifth mold distribution plate may be 0.17 ~ 0.6mm, the diameter of the discharge port may be 5 ~ 50mm, but is not limited thereto, and then, in consideration of the spreading process and the stretching process Setting the diameter of the slit and the like is apparent to those skilled in the art.

On the other hand, the plurality of multi-layer composites are different in the optical thickness, the number of repeating units of the repeating unit of the first and second components laminated alternately to form a different multi-layer composite flow to cover the wavelength range of the different light, respectively can do. To this end, the size of the detention hole, the thickness of the slit, the shape or the number of layers formed in each multi-layer extrusion hole may be different. Through this, the reflective polarizer manufactured through the spreading and stretching process may be formed so that a plurality of repeating units may be combined to form a group, and each group may be set to have a different average optical thickness.

More specifically, optical thickness means n (refractive index) x d (physical thickness). Therefore, if two multilayer composites are formed, if the first component and the second component are the same between the multilayer composites and there is no difference in refractive index, the optical thickness is proportional to the size of the physical thickness d. Therefore, by varying the average value of the physical thickness (d) of the repeating unit of the first component and the second component included in each multilayer composite stream, it is possible to derive the difference in optical thickness between the multilayer composite stream. To this end, by designing the thickness of the slits included in the slit-type extrusion mold differently for each extrusion mold, it is possible to produce multi-layered composites having different average optical thicknesses.

On the other hand, in order to cover the entire visible light region, the average optical thickness of the multilayer composites should be determined to correspond to various light wavelengths. For example, in order to set the average optical thickness of repeating units of a multilayered composite to consist of three composites and to respectively correspond to 450 nm, 550 nm, and 650 nm of the wavelength range of light, the average optical thickness of the repeating units between the multilayered composites. May differ by at least 5%, more preferably by 10% or more. Through this, it is possible to reflect the S-waves in the entire visible light region. In this case, the thicknesses of the first component and the second component forming the same repeating unit may be the same.

In addition, the number, cross-sectional area, shape, diameter of the slit, etc. of the detention holes may also be the same or different in the slit-type extrusion mold forming one multilayer composite flow. Furthermore, the optical thickness of the repeating units forming the same multilayer composite stream may have a deviation of preferably within 20%, more preferably within 15% of the average optical thickness. For example, if the average optical thickness of the repeating units of the first multilayer composite flow is 200 nm, the repeating units forming the same first multilayer composite flow may have an optical thickness variation within about 20%. Meanwhile, the wavelength and the optical thickness of the light are defined according to the following Equation 1.

[Relationship 1]

λ = 4nd

Where λ is the wavelength of light (nm), n is the refractive index, and d is the physical thickness (nm)

Therefore, if the deviation occurs in the optical thickness (nd) can cover not only the wavelength of the target light but also the wavelength range of the light including the same, which is a great help in improving the overall uniform optical properties. Meanwhile, d denotes the thickness of one layer, and since the repeating unit is composed of two layers of the first component and the second component, if the physical thicknesses of the first component and the second component are different, the repeating unit and the wavelength of the light Can be defined according to relation 2 below.

[Relationship 2]

λ = 2 (n ₁ d ₁ + n ₂ d ₂ )

Is the wavelength of light (nm), n ₁ is the refractive index of one layer, n ₂ is the refractive index of two layers, d ₁ is the physical thickness of one layer (nm), and d ₂ is the physical thickness of two layers (nm).

The above-described optical thickness deviation can be achieved by giving a deviation in the number, cross-sectional area, shape, diameter of the slit, etc. in a single slit-type extruded hole, or naturally by the minute minute pressure distribution during the spreading process. It can be.

Therefore, the multiple multilayer composites of the present invention can cover the entire visible light region by differently setting the average optical thickness of the repeating units constituting the composite flow, and the optical thickness appropriate to the repeating units forming one composite flow. Deviation can be made to reflect the S wave of a wide wavelength range. Furthermore, in FIGS. 5 to 7, one multi-layer composite flow is produced in one slit-type extrusion die, but a section is added to the inside of the slit-type extrusion die to produce a plurality of multi-layer composite flows, and one aggregated die is produced. It is also within the scope of the present invention to correspond to the integrated slit-type extruded through one laminated through one. In addition, by designing the thickness of the slits included in the slit-type extrusion die differently for each extrusion die, it is possible to produce a multi-layer composites having a different average optical thickness.

According to another preferred embodiment of the present invention, the first component conveyed in the extruded portion between the steps (1) and (2) is a plurality of agents having different discharge amounts in order to have a different average optical thickness between the multilayer composite flow 1 may further include the step of being discharged into the different slit-type extrusion hole through the pressing means. Specifically, FIG. 9 is a schematic view including a first pressurizing means for forming two multi-layered composite flows, in which a first component conveyed from an extrusion unit (not shown) includes the plurality of first pressurizing means 130 and 131. It is branched to and supplied to the respective slit-type extrusion holes 132 and 133 separately from the respective first

pressing means

130 and 131. At this time, the first pressing means (130, 131) has a different discharge amount from each other through which the area difference occurs and each of the slit-

type extrusion slots

132, 133 are the same specifications (when the diameter of the slit, etc.) is the same The average optical thickness of the first multi-layer composites and the second multi-layer composites formed through may be different.

To this end, the discharge amount of the first pressing means (130, 131) may be preferably 1 to 100 kg / hr, but is not limited thereto.

On the other hand, one first pressing means transfers the first component to the two slit-type extrusion molds, and the two multilayer composite flows formed from the two slit-type extrusion molds are laminated to form one multilayer composite flow, and then one It is also possible for groups to be formed. In this case, four groups may be formed through the four first component pressing means and the eight slit extrusion holes. It is also possible for one first pressing means to convey the first component to three or more slit-type extrusion fittings.

According to another preferred embodiment of the present invention, the second component conveyed in the extrusion section between the steps (1) and (2) is a plurality of agents having different discharge amounts in order to have a different average optical thickness between the multilayer composite flow 2 may be discharged into different slit-type extrusion holes through the pressing means. Specifically, FIG. 10 is a schematic view including two second pressing means to form two multi-layered composite flows, wherein the second component conveyed from the extruder (not shown) is the plurality of second pressing means 140, 141. ) And is supplied separately to the respective slit-type extrusion holes 142, 143 in the respective second

pressing means

140, 141. At this time, the first pressing means (150, 151) has a different discharge amount from each other through each of the slit-type extrusion spheres (152, 153) has the same specifications (when the shape diameter of the island component supply path, etc. are the same). The average optical thickness of the second component of the first multi-layer composites and the second multi-layer composites formed through may be different. To this end, the discharge amount of the second pressurizing means 150 and 151 may be preferably 1 to 100 kg / hr, but is not limited thereto.

On the other hand, one second pressing means transfers the second component to the two slit-type extrusion molds, and the two multilayer composite flows formed from the two slit-type extrusion molds are laminated to form one multilayer composite flow, and then one It is also possible for groups to be formed. In this case, four groups of final reflective polarizers may be formed through four second component pressing means and eight slit extrusion holes. It is also possible for one second pressurizing means to convey the second component to the three or more slit-type extrusion fittings.

As a next step (3), the two or more multilayered composites are laminated together to form a core layer. Specifically, FIG. 11 is a schematic view showing a lamination portion of a multilayer composite stream. The core layer 165 is formed by laminating a plurality of multilayer

composite streams

161, 162, 163, and 164 manufactured through respective slit-type extrusion holes. To form. On the other hand, the laminating step may be carried out in a separate place, or when using a single slit-type extrusion mold may be laminated through a separate aggregated distribution plate. In addition, when the number of multi-layered composites is large, it is also possible to perform a multi-stage lamination in the form of laminating some multi-layered composites first and then laminating them in order to facilitate lamination. On the other hand, in order to laminate the skin layer, preferably the skin layer transferred from the extrusion unit in step (3) is laminated on at least one surface of the core layer, or (3) before the core layer formed through the step (3) The method may further include laminating the core layer. Preferably, the skin layer component may be laminated on both surfaces of the core layer. When the skin layer is laminated on both surfaces, the material and the thickness of the skin layer may be the same or different from each other.

Meanwhile, a separate preliminary spreading step may be further performed to easily spread the repeating unit described later between steps (2) and (3) or between steps (3) and (4).

Next, in step (4), the core layer in which the skin layer is laminated is induced in the flow control unit. Specifically, FIG. 12 is a cross-sectional view of a coat-hanger die, which is a kind of preferred flow control unit that can be applied to the present invention, and FIG. 13 is a side view. Through this, the spreading degree of the core layer may be appropriately adjusted to adjust the repeating unit to have an optical thickness suitable for reflecting light of a desired wavelength. This may be appropriately designed in consideration of further reducing the optical thickness during the stretching process. In detail, since the core layer in which the skin layer transferred through the flow path is laminated in FIG. 12 is widely spread from side to side in the coat-hanger die, the first component included therein is also widely spread from side to side. In addition, as shown in the side view of Figure 13, the coat hanger die is wide spread from side to side but has a structure that is reduced up and down, so that the skin layer is reduced in the horizontal direction of the laminated core layer or reduced in the thickness direction. This is the Pascal principle is applied, the fluid in the closed system is induced to spread wide in the width direction by the principle that the pressure is transmitted to a minute portion by a constant pressure. Therefore, the exit size is wider in the width direction than the inlet size of the die and the thickness is reduced. It uses the Pascal principle that the material in the molten liquid state can be flow and shape control by pressure in the closed system, preferably polymer flow rate and viscosity induction to be a laminar flow of Reynolds number 2,500 or less. When the flow of 2,500 or more turbulent flows, the induction of the plate-like shape is uneven, and there is a possibility of deviation of optical characteristics. The left and right die widths of the exit of the coat-hanger die can be between 800 and 2500 mm, and the fluid flow of the polymer is required to adjust the pressure so that the Reynolds number does not exceed 2,500. The reason is that if it is more than that, the polymer flow becomes turbulent and the core array may be disturbed. In addition, the internal temperature may be 265 ~ 310 ℃.

The flow control unit may be a T-die or a coat-hanger die of a manifold type that may induce the spread of the repeating unit, but is not limited thereto, and may be used without limitation as long as it may induce the spread of the core layer.

According to a preferred embodiment of the present invention, after the step (4), (5) cooling and smoothing the polarizer induced by the spread transferred from the flow control unit, (6) stretching the polarizer after the smoothing step ; And (7) heat setting the stretched polarizer.

First, as a step (5), cooling and smoothing of the polarizer transferred from the flow control unit may be performed by cooling used in the manufacture of a conventional reflective polarizer to solidify it, and then may be performed through a casting roll process or the like.

Thereafter, a process of stretching the polarizer after the smoothing step is performed. The stretching may be performed through a stretching process of a conventional reflective polarizer, thereby causing a difference in refractive index between the first component and the second component to cause a light modulation phenomenon at the interface, and the spread-induced repeating unit may be stretched. Finally, the optical thickness corresponding to the desired light wavelength range is obtained. Therefore, in order to control the optical thickness of the repeating unit in the final reflecting polarizer, the slit diameter of the slit extruded in the slit-type extrusion mold, spreading conditions and draw ratio can be appropriately set. For this purpose, preferably, the stretching step may be performed uniaxially or biaxially, and more preferably, uniaxially. In the case of uniaxial stretching, the stretching direction can be performed in the longitudinal direction. In addition, the draw ratio may be 3 to 12 times. On the other hand, methods for changing an isotropic material to birefringence are commonly known and, for example, when drawn under suitable temperature conditions, the polymer molecules can be oriented so that the material becomes birefringent.

Next, the final reflective polarizer may be manufactured by performing heat setting of the stretched polarizer as step (7). The heat setting may be heat setting through a conventional method, preferably may be performed through an IR heater for 0.1 to 3 minutes at 180 ~ 200 ℃.

On the other hand, in the present invention, if the average optical thickness of the target repeating unit between groups is determined in consideration of this, it is possible to manufacture the reflective polarizer of the present invention by appropriately controlling the specifications of the slit, the specification and the draw ratio of the flow control unit. .

The multilayer reflective polarizer of the present invention manufactured by the above-described method has a first layer having in-plane birefringence and a second layer alternately laminated with the first layer, in order to transmit the first polarized light irradiated from the outside and reflect the second polarized light. Wherein the first layer and the second layer have different refractive indices in at least one axial direction, the first layer and the second layer extend in at least one axial direction, and the first layer and the second layer Is a repeating unit, the repeating units form a group to reflect the shear wave (S wave) of the desired wavelength, the group is two or more, the groups are formed integrally, It includes core layers that differ in average optical thickness. It may also include a skin layer formed integrally on at least one surface of the core layer. In this case, no adhesive layer is formed between the core layer and the skin layer.

14 is a cross-sectional view of a multilayer reflective polarizer in accordance with a preferred embodiment of the present invention. Specifically, skin layers 189 and 190 are integrally formed on both surfaces of the core layer 180, and the core layer 180 is divided into two groups A and B. In the drawing, a dotted line dividing groups A and B means an imaginary line. In group A, the

first layers

181 and 183 corresponding to the first component and the

second layers

182 and 184 corresponding to the second component are alternately stacked. Here, the first layer 181 and the second layer 182 may be defined as one repeating unit R1, and the group A may include at least 25 repeating units. In the group B, the

first layers

185 and 187 and the

second layers

182 and 184 corresponding to the second component are alternately stacked. Here, the first layer 185 and the second layer 186 are defined as one repeating unit (R2), and the group A includes at least 25 repeating units, preferably 50 or more, more preferably 100 More than one, most preferably 150 or more. In addition, the thicknesses of the first layer and the second layer may be the same.

Meanwhile, the average optical thickness of the repeating units R1 included in the group A and the average optical thickness of the repeating units R2 included in the group B are different. Through this, it is possible to reflect the wavelength region of different S waves. In addition, the optical thickness of the repeating units included in the group A may have an optical thickness deviation of preferably within 20%, more preferably within 15% based on the average optical thickness of the group A. Therefore, if the average optical thickness of the group A is 200 nm, the transverse wave (S wave) of the wavelength of 400 nm can be reflected by the above equation (2). In this case, if the thickness variation is 20%, the wavelength band may cover approximately 320 to 480 nm. If the average optical thickness of the repeating units (R2) of group B is 130 nm, it is possible to reflect the transverse wave (S wave) of 520 nm wavelength according to relation 1, and if the thickness deviation is 20%, the wavelength band is approximately 420-620 nm. In this case, it may partially overlap with the wavelength band of Group A, thereby maximizing the light modulation effect. In addition, since the first layer having in-plane birefringence must transmit P wave and reflect S wave, the refractive index n can be set and the average optical thickness can be calculated based on the thickness direction (z-axis refractive index) through which light passes.

15 is a cross-sectional view of a multilayer reflective polarizer according to another exemplary embodiment of the present invention. Referring to the difference from FIG. 14, three groups A, B, and C having different average optical thicknesses are formed inside the core layer, and the average optical thicknesses of the repeating units between the groups are different.

16 is a cross-sectional view of a multilayer reflective polarizer according to another preferred embodiment of the present invention. Specifically, the core layer is formed of four groups, each group may be adjusted the average optical thickness to cover the optical wavelength band of 350nm, 450nm, 550nm and 650nm, respectively. In this case, the outer layer of the core layer may have groups having a large average optical thickness, and the groups having a small average optical thickness may be formed in the inner layer. On the other hand, in order to cover the entire visible light region, the average optical thickness of the repeating units must be determined to correspond to various light wavelengths. To set the average optical thickness of repeating units for each group within the core layer to correspond to the optical wavelength bands of 350 nm, 450 nm, 550 nm, and 650 nm, the average optical thickness of the first component between the groups may differ by at least 5% or more. More preferably, 10% or more. Through this, it is possible to reflect the S-waves in the entire visible light region.

On the other hand, there is no adhesive layer between the group and the group is formed integrally. It is also integrally formed between the core layer and the skin layer. As a result, the deterioration of the optical properties due to the adhesive layer can be prevented, and more layers can be added to the limited thickness, thereby significantly improving the optical properties. Furthermore, since the skin layer is manufactured at the same time as the core layer and then the stretching process is performed, the skin layer of the present invention can be stretched in at least one axial direction, unlike the conventional core layer stretching, after the stretching with the unstretched skin layer. As a result, the surface hardness is improved compared to the unstretched skin layer, thereby improving scratch resistance and heat resistance.

According to a preferred embodiment of the present invention, a birefringent interface may be formed between the first layer and the second layer forming the core layer. Specifically, in the multilayer reflective polarizer in which the first layer and the second layer are alternately stacked, the magnitude of the substantial coincidence or inconsistency of the refractive indices along the X, Y, and Z axes in the space between the first layer and the second layer is the axis. This affects the degree of scattering of the polarized light. 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 second layer along a certain axis is substantially coincident with the refractive index of the first layer, incident light polarized with an electric field parallel to this axis is not scattered regardless of the size, shape and density of the portion of the first layer. Will pass through the first floor. Also, when the refractive indices along that axis are substantially coincident, the light beam passes through the object without being substantially scattered. More specifically, the first polarized light (P wave) is transmitted without being affected by the birefringent interface formed at the boundary between the second layer and the first layer, but the second polarized light (S wave) is transmitted to the second layer and the first layer. Modulation of light occurs due to the influence of the birefringent interface formed at the boundary. Through this, the P wave is transmitted, and the S wave generates light modulation such as scattering and reflection of light, and thus, polarization is separated.

Accordingly, since the first layer and the second layer may have a birefringent interface formed at their surface, the light modulation effect may be induced. When the second layer is optically isotropic, the first layer may have birefringence. Specifically, when the refractive index in the x-axis direction of the first layer 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 indices of the second layer are nX2, nY2 and nZ2, nX1 and nY1 In-plane birefringence can occur. More preferably, at least one of the X, Y, and Z axis refractive indices may be different from each other in the first layer and the second layer, and more preferably, the difference in refractive index with respect to the Y and Z axis directions when the extension axis is the X axis Is 0.05 or less, and the difference in refractive index with respect to the X-axis may be 0.1 or more. On the other hand, if the difference in refractive index is 0.05 or less, it is usually interpreted as matching.

On the other hand, according to a preferred embodiment of the present invention, the total number of layers of the multilayer reflective polarizer may be 100 to 2000. The thickness range of the repeating unit may be appropriately designed according to the wavelength range and the refractive index of the desired light, preferably 65 to 300nm. The thicknesses of the first layer and the second layer forming the repeating unit may be the same or different. Meanwhile, in the present invention, the thickness of the core layer is 10 to 300 μm, and the thickness of the skin layer may be 50 to 190 μm, but is not limited thereto.

If the extruder includes an extruded portion into which the skin layer component is separately added to at least one surface of the core layer, the multi-layered composite flow communicated with the extruder into which the skin layer component is injected and transferred from the spin block portion. It may further include a feed block unit for laminating the skin layer on at least one side of the. Alternatively, according to another preferred embodiment of the present invention, when the extruder includes an extruded portion into which the skin layer component is separately added, at least a core layer formed in communication with the extruder into which the skin layer component is injected and the collection block portion. The skin layer may be laminated on one surface.

17 is a schematic diagram of an apparatus for manufacturing a multilayer reflective polarizer in which a skin layer and a core layer are integrally formed in accordance with a preferred embodiment of the present invention. Specifically, the first extrusion part 220 to which the first component is injected, the second extrusion part 221 to which the second component is injected, and the third extrusion part 222 to which the skin layer component is injected are included. The first extrusion portion 220 is in communication with the spin block portion (C) comprising four slit-shaped extrusion holes (223, 224, 225, 226). At this time, the first extruder 220 supplies the first slit extruded

holes

223, 224, 225, and 226 in a molten state. The second extrusion part 221 is also in communication with the spin block part (C) and supplies the second component in the molten state to the four slit-type extrusion holes (223, 224, 225, 226) included therein. Four slit extruded

molds

223, 224, 225, and 226 produce four multilayered composites in which the first and second components are alternately stacked and the average optical thickness of the repeating units is different. To this end, the respective slit diameters of the four slit-type extrusion fittings may be different. The four slit-type extrusion holes 223, 224, 225, and 226 may be the slit type extrusion holes shown in FIG. 5. In addition, although four slit-type extrusion molds are exemplified, the use of one integrated slit-type extrusion mold is naturally included in the scope of the present invention. Four multi-layered composite streams manufactured through the four slit-shaped extrusion holes 223, 224, 225, and 226 are laminated together in the collection block portion 227 to form one core layer. In this case, the collection block portion 227 may be formed separately, or in the case of using a single integrated slit-type extrusion mold, the multi-layered composites may be laminated in the form of a collection mold in the slit-type extrusion mold. The core layer laminated in the collection block portion 227 is transferred to the feed block portion 228 and then laminated with the skin layer component transferred from the third extrusion portion 222. Therefore, the third extrusion part 222 and the feed block portion 228 may be in communication with each other. Thereafter, the core layer in which the skin layer is laminated is transferred to the flow control unit 229, and the spread of the first component is induced. Preferably the flow control part may be a T-die or a coat-hanger die. Meanwhile, when the core layer and the skin layer are laminated in the collection block unit 227, the feed block unit 228 may be omitted.

18 is a schematic diagram of an apparatus for manufacturing a reflective polarizer in which a polymer is dispersed according to another exemplary embodiment of the present invention. 17, the first extrusion part 220 transfers the first component to the four first

pressing means

233, 234, 235, and 236. The first pressurizing means 233, 234, 235, and 236 have different discharge amounts, and discharge the first component to the plurality of slit-type extrusion holes 241, 242, 243, and 244. The second extrusion part 221 transfers the second component to the four second

pressing means

237, 238, 239 and 240. The second pressurizing means 237, 238, 239, and 240 have different discharge amounts, and discharge the second component into the plurality of slit-type extrusion holes 241, 242, 243, and 244. Four slit extruded

molds

241, 242, 243 and 244 produce four multilayered composites with different average optical thicknesses. The first pressurizing means, the second pressurizing means and the plurality of slit-type extrusion molds form the spin block portion (C).

19 is a schematic diagram of an apparatus for manufacturing a reflective polarizer in which a polymer is dispersed according to another exemplary embodiment of the present invention. Briefly focusing on the difference from FIG. 18, it is characterized by using 8 slit extruded holes, not 4 slit extruded holes, in order to manufacture a multilayer reflective polarizer having 4 groups. . Specifically, the first pressurizing means 233 discharges the first component to the two slit-type extrusion holes 250 and 251. The second pressurizing means 234 also discharges the first component to the two slit-type extrusion holes 250 and 251. The two slit-shaped extrusion holes 250 and 251 have the same optical thickness between the multilayer composite streams because the first and second components are transferred through the same first and second pressing means. In this way, eight multilayer composites are formed, each of which has the same average optical thickness. The two multilayer composites having the same average optical thickness are respectively laminated at the

first laminations

258, 259, 260, and 261 to form four multilayer composites, and the four multilayer composites are arranged at the second lamination 262. ) To form one core layer.

Meanwhile, in FIG. 19, one first pressing means transfers the first component to the two slit-type extrusion molds, but it is apparent to those skilled in the art that the first component can be transferred to the two or more slit-type extrusion molds. The same may be applied to the second pressing means.

On the other hand, according to a preferred embodiment of the present invention, there is provided a liquid crystal display device comprising the reflective polarizer of the present invention. Specifically, FIG. 20 is an example of a liquid crystal display device employing a reflective polarizer of the present invention, in which a reflecting plate 280 is inserted into a frame 270, and a cold cathode fluorescent lamp 290 is disposed on an upper surface of the reflecting plate 280. Is located. An optical film 320 is positioned on an upper surface of the cold cathode fluorescent lamp 290, and the optical film 320 includes a diffuser plate 321, a light diffusion film 322, a prism film 323, and a reflective polarizer ( 324 and the absorption polarizing film 325 are laminated in this order, but the stacking order may vary depending on the purpose or some components may be omitted or a plurality may be provided. For example, the diffusion plate 321, the light diffusing film 322, the prism film 323, 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 310 may be inserted into the mold frame 300 on the upper surface of the optical film 320.

Looking at the center of the light path, the light irradiated from the cold cathode fluorescent lamp 290 reaches the diffusion plate 321 of the optical film 320. The light transmitted through the diffusion plate 321 passes through the light diffusion film 322 in order to propagate the light in the vertical direction with respect to the optical film 320. The film passing through the light diffusion film 322 passes through the prism film 323 and reaches the reflective polarizer 324 to generate light modulation. Specifically, the P wave transmits the reflective polarizer 324 without loss, but in the case of the S wave, light modulation (reflection, scattering, refraction, etc.) is generated, and again, by the reflecting plate 280 that is the rear side of the cold cathode fluorescent lamp 290. Reflected and the nature of the light is randomly changed to P wave or S wave and then pass through the reflective polarizer 324 again. After passing through the absorption polarizing film 325, the liquid crystal display panel 310 is reached. As a result, when the reflective polarizer of the present invention is used by being inserted into the liquid crystal display device, a dramatic improvement in luminance can be expected as compared with a conventional reflective polarizer. Meanwhile, the cold cathode fluorescent lamp 290 may be replaced with an LED.

In the present invention, the use of the reflective polarizer has been described based on the liquid crystal display, but the present invention is not limited thereto, and may be widely used in flat panel display technologies such as a projection display, a plasma display, a field emission display, and an electroluminescent display.

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.

The process was performed as shown in FIG. 17. Specifically, PEN having a refractive index of 1.65 as a first component and dimethyl terephthalate and dimethyl-2,6-naphthalene dicarboxylate as a second component were mixed in an molar ratio of 6: 4 to ethylene glycol (EG) and 1. : Refractive index polymerized to 90% by weight of polycarbonate and polycyclohexylene dimethylene terephthalate (PCTG) as a co-PEN and skin layer component having a refractive index of 1.64 reacted at a molar ratio of 2 Polycarbonate alloys of 1.58 were charged to the first extruded portion, the second extruded portion, and the third extruded portion, respectively. The extrusion temperature of the 1st component and the 2nd component shall be 295 degreeC, and I.V. The polymer flow was corrected through the adjustment, and the skin layer was subjected to the extrusion process at a temperature level of 280 ° C.

Four composites with different average optical thicknesses were prepared using four slit-shaped extrusion holes in FIGS. 6 and 7. Specifically, the first component conveyed in the first extruded part was distributed to four slit-type extruded parts, and the second component conveyed in the second extruded part was transferred to four slit-type extruded parts. One slit-type extrusion mold is composed of 300 layers, the thickness of the slit of the first slit-type extrusion mold on the bottom of the fifth mold distribution plate of FIG. 7 is 0.26 mm, and the slit thickness of the second slit extrusion mold is 0.21 mm. The slit thickness of the third slit extruded die was 0.17 mm, the slit thickness of the fourth slit extruded die was 0.30 mm, and the diameter of the discharge port of the sixth die distribution plate was 15 mm 15 mm. The four composite streams discharged through the four slit-type extrusion holes were transferred through separate flow paths and then laminated in a collection block to form one core layer polymer. In the feed block having a three-layer structure, a skin layer component flowed through the flow path from the third extrusion part to form a skin layer on the upper and lower surfaces of the core layer polymer. Spread was induced in the coat hanger die of FIGS. 12 and 13 to correct the flow rate and pressure gradient of the core layer polymer having the skin layer formed thereon. Specifically, the width of the die inlet is 200 mm, the thickness is 20 mm, the width of the die outlet is 960 mm, the thickness is 2.4 mm, and the flow rate is 1 m / min. A smoothing process was then performed on the cooling and casting rolls and stretched six times in the MD direction. Subsequently, heat setting was performed through an IR heater at 180 ° C. for 2 minutes to prepare a multilayer reflective polarizer as shown in FIG. 16. The refractive index of the first component of the prepared reflective polarizer was (nx: 1.88, ny: 1.64, nz: 1.64) and the refractive index of the second component was 1.64. Group A had 300 layers (150 repeating units), and the repeating unit had a thickness of 168 nm, an average optical thickness of 275.5 nm, and an optical thickness deviation of about 20%. Group B consisted of 300 layers (150 repeating units) with a thickness of 138nm, an average optical thickness of 226.3nm, and an optical thickness deviation of about 20%. Group C had 300 layers (150 repeating units) with a repeating unit thickness of 110 nm, an average optical thickness of 180.4 nm, and an optical thickness deviation of about 20%. The D group had 300 layers (150 repeating units), the thickness of the repeating unit was 200nm, the average optical thickness was 328nm, and the optical thickness deviation was about 20%. The core thickness of the manufactured multilayer reflective polarizer was 92.4 µm and the skin layer thickness was 153.8 µm, respectively, so that the total thickness was 400 µm.

An 800-layer reflective polarizer was prepared in the same manner as in Example 1 except that the number of layers of the four slit-type extrusion holes was 200 each. The core layer thickness of the final product was 61.6 mu m and the skin layer thickness was 169.2 mu m, respectively, so that the total thickness was 400 mu m.

A 600-layer reflective polarizer was prepared in the same manner as in Example 2 except that the third slit-type extrusion slot was not used.

Comparative Example 1

The same procedure as in Example 2 was carried out except that the thickness of the slits of the four extruded slits was the same as that of the slits of the first slits.

Comparative Example 2

In Example 1, four groups were individually formed into sheets through four slit extruded molds and drawn individually. Thereafter, four groups made of a sheet were adhered through a pressure sensitive adhesive to form a core layer, and then a skin layer was attached to both surfaces of the core layer with a pressure sensitive adhesive to prepare an 800 layer reflective polarizer. The manufactured reflective polarizer has a thickness of 83.2 μm in the core layer and 158.4 μm in the thickness of the skin layer. The total thickness was 400 µm, and the pressure-sensitive adhesive layer was included in the thickness of the core layer and the skin layer.

Experimental Example

The following physical properties of the reflective polarizers prepared through Examples 1 to 3 and Comparative Examples 1 to 2 were evaluated, and the results are shown in Table 1 below.

1. Transmittance

Transmission axis transmittance and reflection axis transmittance were measured by ASTM D1003 method using COH300A analysis equipment of NIPPON DENSHOKU, Japan.

2. Polarization degree

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

3. Relative luminance

In order to measure the brightness of the prepared reflective polarizer was performed as follows. After assembling the panel on a 32 "direct backlight unit equipped with a diffuser plate and a reflective polarizer, the luminance was measured at nine points using a BM-7 measuring instrument manufactured by Topcon Corporation.

The relative luminance shows the relative values of the luminance of the other examples and the comparative examples when the luminance of the reflective polarizer of Example 1 is 100 (reference).

Table 1

	Relative luminance (%)	Polarization degree (λ = 550nm)			Polarization degree (λ = 650nm)
	Relative luminance (%)	Polarization degree	Transmission axis transmittance	Reflective axis transmittance	Polarization degree	Transmission axis transmittance	Reflective axis transmittance
Example 1	100	93%	88%	3%	85.3%	88%	7%
Example 2	97.2	89.4%	89%	5%	79.8%	89%	10%
Example 3	94.2	85.5%	90%	7%	76.5%	90%	12%
Comparative Example 1	84.8	73%	89%	14%	66.4%	89%	18%
Comparative Example 2	92.7	85.3%	88%	7%	76%	88%	12%

As can be seen from Table 1, it can be confirmed that the reflective polarizers of Examples 1 to 3 of the present invention have significantly improved optical properties compared to the reflective polarizers of Comparative Examples 1 and 2. In addition, Comparative Example 2 including the adhesive layer is lower in optical properties than Example 2, which does not include the same number of adhesive layers. This is because optical properties are deteriorated due to destructive interference with respect to the optical wavelength by the adhesive layer.

Since the reflective polarizer of the present invention has excellent light modulation performance, it can be widely used in a field requiring modulation of light. Specifically, it can be widely used in flat panel display technologies such as liquid crystal displays, projection displays, plasma displays, field emission displays, and electroluminescent displays requiring high brightness such as mobile displays, LCDs, and LEDs.

Claims

A method of manufacturing a multilayer reflective polarizer comprising a core layer in which a first component and a second component are alternately laminated,

(1) supplying the first component and the second component to the extrusion parts, respectively;

(2) forming two or more multilayered composites in which the repeating units of the first component and the second component are alternately laminated, wherein each of the multilayered composites reflects a shear wave (S wave) of a desired wavelength; Injecting the first component and the second component transferred from the plurality of slit-type extrusion molds to form two or more multilayered composites having different average optical thicknesses of the repeating units;

(3) laminating the two or more multilayered composites into one to form a core layer; And

(4) inducing spreading of the core layer in the flow control unit.
The method of claim 1,

When the skin layer component is supplied to the extruder in the step (1), the skin layer component transferred from the extruder is laminated on at least one surface of the core layer formed in the step (3) between the steps (3) and (4). Method for producing a multilayer reflective polarizer, characterized in that it further comprises the step.
The method of claim 1,

When the skin layer component is supplied to the extruder in the step (1), the method of manufacturing a multilayer reflective polarizer comprising laminating the skin layer component transferred from the extruder to at least one surface of the core layer in the step (3).
The method of claim 1,

Step (2) is a method for producing a multilayer reflective polarizer, characterized in that to form four or more multilayered composites.
The method of claim 1, wherein the plurality of slit-type extrusion holes are integrated.
The method of claim 1, wherein the step (1) and (2)

The first component conveyed from the extruder further comprises the step of ejecting into different slit-type extrusion slots respectively through a plurality of first pressing means having a different discharge amount in order to have a different average optical thickness between the multi-layer composite flow Method of manufacturing a multilayer reflective polarizer.
The method of claim 1, wherein the step (1) and (2)

The second component conveyed from the extruded part is discharged into different slit-type extrusion holes through a plurality of second pressing means having a different discharge amount in order to have a different average optical thickness between the multi-layer composite flow.
2. The multilayer according to claim 1, wherein the plurality of slit-type extrusion molds have different diameters of slits on the mold distribution plate to which the first component and the second component are supplied and distributed to produce different multilayer composites. Reflective polarizer manufacturing method.
The method of claim 1,

The plurality of slit-type extrusion mold is a multilayer reflective polarizer manufacturing method, characterized in that the number of layers of the detention hole is 200 or more.
The method of claim 1,

The plurality of slit-type extrusion mold is a multilayer reflective polarizer manufacturing method, characterized in that the number of layers of the detention hole of each slit-type extrusion mold is 300 or more.
The method of claim 1, wherein the optical thicknesses of repeating units forming the same multilayered composite have a variation within 20% of the average optical thickness.
The method of claim 1, wherein the optical thicknesses of repeating units forming the same multilayered composite have a variation within 15% of the average optical thickness.
The method of claim 1, wherein the plurality of multilayer composites have an average optical thickness of 10% or more.
An apparatus for manufacturing a multilayer reflective polarizer comprising a core layer in which a first component and a second component are alternately laminated,

Two or more extrusion parts into which the first component and the second component are separately input;

The repeating unit of the first component and the second component forms two or more multilayered composite flows in which the laminated units are alternately stacked, and each of the multilayer composite flows is transferred from the extruder to reflect the shear wave (S wave) of a desired wavelength. A spin block portion including a slit-type extrusion block for inputting a first component and a second component to produce two or more multilayered composites having different average optical thicknesses of repeating units;

A collection block unit for laminating the two or more multi-layer composite streams transferred from the spin block unit to one to form a core layer; And

Apparatus for manufacturing a multilayer reflective polarizer comprising a flow control unit for inducing the spread of the core layer transferred from the collection block unit.
The skin layer of claim 14, wherein the extruder includes an extruded part into which the skin layer component is separately added. Apparatus for manufacturing a multilayer reflective polarizer characterized in that it further comprises a feed block unit for laminating.
The skin layer is laminated on at least one surface of the core layer formed in communication with the extruder into which the skin layer component is added and the collection block portion. Apparatus for producing a multilayer reflective polarizer, characterized in that.
15. The island-in-the-sea type extrusion mold of claim 14, wherein the spin block portion discharges the first component transferred from the extruder to supply the island-in-the-sea extrusion mold, and the island-in-the-sea extrusion mold by discharging the second component transferred from the extrusion portion. And a second pressing means for supplying it to the apparatus for manufacturing a multilayer reflective polarizer.