WO2013100661A1

WO2013100661A1 - Reflective polarizer having dispersed polymer

Info

Publication number: WO2013100661A1
Application number: PCT/KR2012/011632
Authority: WO
Inventors: 조덕재; 한정완; 백명기; 고승진; 이황규
Original assignee: 웅진케미칼 주식회사
Priority date: 2011-12-29
Filing date: 2012-12-27
Publication date: 2013-07-04
Also published as: TW201334963A; TWI543865B

Abstract

A reflective polarizer according to the present invention is provided with a plurality of groups having different mean optical widths formed in a single integrated body, and thus does not include a separate adhesive layer and/or a protective boundary layer (PBL) in the interior of a core layer and in between a core layer and a skin layer. As such, manufacturing costs may be significantly reduced, and optical properties can be favorably maximized within the restricted widths. Additionally, as a plurality of groups having different mean optical widths are formed, all S waves within the visible wavelength range are reflected.

Description

Reflective polarizer with dispersed polymer

The present invention provides a reflective polarizer in which a polymer is dispersed, and more particularly, a reflective polarizer in which a polymer is dispersed, which is very advantageous for maximizing optical properties at a limited thickness.

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, in order to make a multi-layered structure, a group of 209 layers is formed through the process of folding a 2-layered structure to form a 4-layered structure and a continuous folding type of multi-layered structure. It was difficult to form groups inside the multilayer in the process. 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 capable of achieving the function of the reflective polarizer by dispersing a birefringent polymer extending 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.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-described problems, and the first object of the present invention is to provide a reflective polarizer in which a polymer is significantly improved in optical properties with respect to a reflective polarizer in which a conventional polymer is dispersed.

A second object of the present invention is to provide a reflective polarizer in which a polymer is dispersed, which can be manufactured integrally without forming a separate adhesive layer between each group inside the core layer and between the core layer and the skin layer.

In order to solve the above problems, the reflective polarizer in which the polymer of the present invention is dispersed includes a plurality of plate-shaped polymers dispersed in the substrate to transmit the first polarized light irradiated from the outside and reflect the second polarized light. The plate-shaped polymer has a refractive index different from the substrate in at least one axial direction, the substrate is elongated in at least one axial direction, and the plurality of plate-shaped polymers each form a group to reflect a shear wave (S wave) of a desired wavelength. A plurality of groups are formed, and the group includes a core layer having a different average optical thickness of the plate-shaped polymers between groups and a skin layer integrally formed on at least one surface of the core layer.

According to a preferred embodiment of the present invention, the first polarization may be longitudinal, and the second polarization may be transverse.

According to another preferred embodiment of the present invention, the substrate is polyethylene naphthalate (PEN), copolyethylene naphthalate (co-PEN), polyethylene terephthalate (PET), polycarbonate (PC), polycarbonate (PC) Earl Roy, 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 And at least one of epoxy (EP), urea (UF), melanin (MF), unsaturated polyester (UP), silicone (SI), elastomer and cycloolefin polymer.

According to another preferred embodiment of the present invention, the polymer is polyethylene naphthalate (PEN), copolyethylene naphthalate (co-PEN), polyethylene terephthalate (PET), polycarbonate (PC), polycarbonate (PC) Alloy, polystyrene (PS), heat-resistant polystyrene (PS), polymethyl methacrylate (PMMA), polybutylene terephthalate (PBT), polypropylene (PP), polyethylene (PE), acrylonitrile butadiene styrene (ABS ), Polyurethane (PU), polyimide (PI), polyvinyl chloride (PVC), styrene acrylonitrile mixture (SAN), ethylene vinyl acetate (EVA), polyamide (PA), polyacetal (POM), It may be one or more of phenol, epoxy (EP), urea (UF), melanin (MF), unsaturated polyester (UP), silicone (SI), elastomer and cycloolefin polymer.

According to another preferred embodiment of the present invention, the difference in the refractive index of the substrate and the polymer may be greater than the difference in the refractive index of the extended axial direction of the other axial refractive index.

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

According to another preferred embodiment of the present invention, the polymer may be elongated in the longitudinal direction.

According to another preferred embodiment of the present invention, the plurality of polymers may form three groups to reflect light of three wavelength bands.

According to another preferred embodiment of the present invention, the plurality of polymers may form four groups to reflect light in four wavelength bands.

According to another preferred embodiment of the present invention, the optical thickness of the polymer may be 1/4 of the desired light wavelength (λ).

According to another preferred embodiment of the present invention, the desired wavelength may include a visible light band.

According to another preferred embodiment of the present invention, the optical thickness of the polymers included in the same group may have a thickness deviation within 30% of the average optical thickness.

According to another preferred embodiment of the present invention, the optical thickness of the polymers included in the same group may have a thickness deviation within 20% of the average optical thickness.

According to another preferred embodiment of the present invention, the optical thickness of the polymers included in the same group may have a thickness deviation within 15% of the average optical thickness.

According to another preferred embodiment of the present invention, the three reflection bands may include a wavelength band of 450nm, 550nm and 650nm.

According to another preferred embodiment of the present invention, the four reflection bands may include a wavelength band of 350nm, 450nm, 550nm and 650nm.

According to another preferred embodiment of the present invention, the plurality of groups may differ from the average optical thickness of the polymers of at least 5%, more preferably at least 10%.

According to another preferred embodiment of the present invention, the polymer satisfying the aspect ratio of the plurality of polymers may be 50% or more.

According to another preferred embodiment of the present invention, the plurality of groups may form a plurality of spaced apart layers based on the longitudinal cross section of the polymer.

According to another preferred embodiment of the present invention, the plurality of polymers included in one group are arranged spaced apart from each other and at least 25 or more and more preferably 50 or more spaced layers based on the longitudinal cross section of the polymer. Can be formed.

According to another preferred embodiment of the present invention, the plate-shaped polymer has an aspect ratio of the short axis length to the long axis length based on the vertical section in the longitudinal direction of 1/1000 or less, 1/2000 or less, 1/3000 or less, 1 / It may be 5000 or less, 1/10000 or less, 1/20000 or 1/30000 or less.

According to another preferred embodiment of the present invention, a birefringent interface may be formed between the polymer and the substrate.

According to another preferred embodiment of the present invention, the polymer has optical birefringence, and the substrate may be optically isotropic.

According to another preferred embodiment of the present invention, an adhesive layer may not be formed between the group and the group and / or between the core layer and the skin layer.

Hereinafter, the terms used in the present specification will be briefly described.

"Polymers have birefringence" means that when light is irradiated on fibers with different refractive indices, the light incident on the polymer is refracted by two or more lights with different directions.

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

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

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

'Aspect ratio' means the ratio of the short axis length to the long axis length based on the vertical section in the longitudinal direction of the elongated body.

Since the reflective polarizer of the present invention is formed integrally with a plurality of groups having different average optical thicknesses, a separate adhesive layer and / or protective layer PBL is not included in the core layer and between the core layer and the skin layer. This not only significantly reduces the manufacturing cost but is also very advantageous in maximizing optical properties at a limited thickness. In addition, since a plurality of groups having different average optical thicknesses are formed, all S waves in the visible light wavelength region can be reflected.

Furthermore, since the polymer inside the substrate has a plate-like shape, it is possible to achieve very excellent optical properties even when the bipolar birefringent polymer contains a very small number of the same area compared to the reflective polarizer including the conventional birefringent polymer.

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.

5 is a cross-sectional view of a reflective polarizer according to an exemplary embodiment of the present invention.

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

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

8 is a perspective view of a reflective polarizer according to an exemplary embodiment of the present invention.

9 is a cross-sectional view of a plate-like polymer according to an embodiment of the present invention.

10 and 11 are perspective views showing the coupling structure of the distribution plate of the sea-island extrusion mold that can be used in the present invention.

12 is a cross-sectional view of the distribution plate according to another preferred embodiment of the present invention.

13 and 14 are cross-sectional views showing in detail the arrangement of the island component supply path of the detention distribution plate according to an embodiment of the present invention.

15 and 16 are perspective views showing the coupling structure of the distribution plate of the sea-island type extrusion mold that can be used in the present invention.

17 is a view showing a plurality of islands-in-the-sea extrusion molds according to an embodiment of the present invention.

18 is a schematic view including first pressurizing means to form two islands-in-the-sea composite flows in accordance with one preferred embodiment of the present invention.

19 is a schematic diagram comprising two second pressurizing means to form two islands-in-the-sea composite flow according to one preferred embodiment of the present invention.

20 is a schematic view including one second pressurizing means to form two islands-in-the-sea composite flow according to one preferred embodiment of the present invention.

21 is a schematic view showing the lamination of the island-in-the-sea composite products according to one preferred embodiment of the present invention.

Figure 22 is a cross sectional view of a coat-hanger die in accordance with a preferred embodiment of the present invention, and Figure 23 is a side view.

24 is a schematic diagram of an apparatus for manufacturing a reflective polarizer in which a polymer is dispersed according to a preferred embodiment of the present invention.

25 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.

26 is a schematic diagram of an apparatus for manufacturing a reflective polarizer in which a polymer is dispersed according to another preferred embodiment of the present invention.

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

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

According to a preferred embodiment of the present invention, the reflective polarizer in which the polymer of the present invention is dispersed includes a plurality of plate-shaped polymers dispersed in the substrate in order to transmit the first polarized light emitted from the outside and reflect the second polarized light. Wherein the plurality of plate-shaped polymers have a refractive index different from the substrate in at least one axial direction, the substrate extends in at least one axial direction, and each of the plurality of plate-shaped polymers has a shear wave (S wave) of a desired wavelength. A group is formed to reflect, and a plurality of groups are formed, and the group includes a core layer having a different average optical thickness of the plate-shaped polymers between groups and a skin layer integrally formed on at least one surface of the core layer.

5 is a cross-sectional view of a reflective polarizer according to an exemplary embodiment of the present invention. Specifically, skin layers 186 and 187 are 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. The average optical thickness of the plate-shaped

polymers

181 and 182 as the first component included in group A and the average optical thickness of the plate-shaped polymers 183 and 184 as the first component included in the group B are different. Through this, it is possible to reflect the wavelength range of different light.

In addition, the optical thickness of the plate-shaped

polymers

181 and 182 as the first component included in the group A is within 30%, preferably within 20%, more preferably within 15% based on the average optical thickness of the group A. It may have an optical thickness deviation. In this case, the optical thickness means n (refractive index) x d (physical thickness). 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 average optical thickness of the group A is 100 nm, the transverse wave (S wave) of 400 nm wavelength can be reflected by the relational formula (1). 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 plate-shaped

polymers

233 and 234 of group B is 130 nm, the transverse wave (S wave) of 520 nm wavelength can be reflected by Equation 1, and if the thickness deviation is 20%, it is approximately 420 to 620 nm. The wavelength band may be covered, and in this case, the wavelength band may partially overlap with the wavelength band of group A, thereby maximizing light modulation effects. In addition, when the plate-like polymer, which is the first component, has optical birefringence, P waves must be transmitted and S waves must be reflected, so that the refractive index n is set based on the thickness direction (z-axis refractive index) through which light passes, and the average optical thickness is calculated. can do.

On the other hand, the maximum value of the distance between the polymers in the groups A and B may be smaller than the maximum value of the distance between the plate-shaped polymers between the groups A and B. Specifically, the maximum value d ₁ of the distance between the plate-shaped polymers of group A and the maximum value d ₂ of the distance between polymers of group B are smaller than the maximum value d _{3 of the} distance between polymers of groups A and B. In other words, the spacing between the plate-shaped polymers in the same group may be smaller than the distance between polymers between adjacent groups, and thus may be integrally formed between groups even without forming an adhesive layer between groups.

In addition, the polymers dispersed in the core layer form a plurality of layers having a space between them. In this case, the number of layers formed by the plate-like polymers in one group may be 25 or more, preferably 50 or more, more preferably 100 or more, most preferably 150 or more, or 200 or more. .

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.

6 is a cross-sectional view of a reflective polarizer according to another exemplary embodiment of the present invention. Referring to the difference from FIG. 5, three groups A, B, and C having different average optical thicknesses are formed inside the core layer, and the maximum value of the distance between the plate-shaped polymers within the groups A, B, and C is formed. This may be less than the maximum value of the interpolymer distance between groups A, B and C.

7 is a cross-sectional view of a 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. Meanwhile, in order to cover the entire visible light region, the average optical thickness of the polymers must be determined to correspond to various light wavelengths. To set the average optical thickness of the first component of 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 polymers between the groups may differ by at least 5% or more. More preferably, it may differ by 10% or more. Through this, it is possible to reflect the S-waves in the entire visible light region.

On the other hand, the area of the plate-shaped polymers in a certain area within the same group may be larger than the area of the plate-shaped polymers in a certain area between groups. Specifically, the density of the polymers in the constant area S ₁ inside the group A and the constant area S ₂ inside the group B is greater than the constant area S ₃ between the group A and the group B. In other words, the area occupied by (μm ² ) plate-shaped polymers per unit area in the same group is larger than the area occupied by (μm ² ) plate-shaped polymers per unit area in the group and between groups.

8 is a perspective view of a reflective polarizer according to an exemplary embodiment of the present invention, in which a plurality of plate-like polymers 211 are elongated in the longitudinal direction and the cross-section is plate-shaped in the second component 210. In this case, each of the plate-shaped polymer 211 can be elongated in various directions, but preferably it is advantageously extended in parallel in any one direction, more preferably between the elongated body in a direction perpendicular to the light irradiated from an external light source Stretching parallel to is effective to maximize the light modulation effect.

According to one preferred embodiment of the present invention, an aspect ratio whose vertical cross section in the longitudinal direction of the plate-shaped polymer is a short axis length with respect to a long axis length may be 1/1000 or less. 9 is a vertical cross section in the longitudinal direction of a plate-like polymer that can be used in the present invention, wherein the ratio of the relative length of the major axis length (a) and the minor axis length (b) when the major axis length is a and the minor axis length is b (aspect ratio) ) Should be less than 1/1000. In other words, when the long axis length (a) is 1000, the short axis length (b) should be less than or equal to 1, which is 1/1000. If the ratio of the short axis length to the long axis length is larger than 1/1000, it is difficult to achieve the desired optical properties. The aspect ratio can be appropriately adjusted through the induction and stretching of the first component in the above-described manufacturing step. On the other hand, although the cross section of the polymer is shown as a ratio of the short axis length to the long axis length is greater than 1/1000 in the drawings of the present invention, this is only a problem of the method represented in the drawings for the sake of understanding, in practice Compared with the polymer, the long axis direction is longer and the short axis direction is shorter.

Specifically, when the display is 32 inches based on the vertical cross-section of the reflective polarizer and is 1580 mm and has a height of 400 μm, the conventional reflective polarizer may include 100 million or more birefringent polymers to achieve desired optical properties. On the other hand, the reflective polarizer of the present invention can achieve optical properties in which the transmittance in the transmission axis direction of the reflective polarizer is 90% or more and the transmittance in the reflection axis direction is 30% or less even when one or more of the plate-shaped polymers are included. More preferably, the transmittance in the transmission axis direction is 87% or more, the optical property of the transmittance in the reflection axis direction can be achieved 10% or less, most preferably the transmission axis transmittance is 85% or more and the reflection axis The transmittance may be 7% or less. In this case, preferably, the reflective polarizer of the present invention may contain 500,000 or less of the planar polymers, and most preferably, 300,000 or less of the planar polymers. To this end, according to a preferred embodiment of the present invention, the ratio of the short axis length to the long axis length of the polymer is preferably 1/1000 or less, more preferably 1/1500 or less, even more preferably 1/2000 or less, further Preferably less than 1/3000, more preferably less than 1/5000, more preferably less than 1/10000 or less than 1/20000, more preferably less than 1/30000, more preferably less than 1/50000, most Preferably, it may be 1/70000 to 1/170000.

As a result, as the ratio of the short axis length to the long axis length is smaller, the desired optical properties can be achieved even if a smaller number of plate-shaped polymers are included in the substrate.

However, when the aspect ratio of the plate-shaped polymer becomes very small, the spacing space between the plate-like polymers forming the same layer may be extremely small. However, the reflective polarizer of the present invention will necessarily have at least one space between the plate-like polymers forming the same layer.

On the other hand, according to a preferred embodiment of the present invention in order to achieve the above-described optical properties, the reflective polarizer is 50% or more of the plurality of plate-like polymers satisfying the above aspect ratio conditions of all the plate-shaped polymer contained in the substrate, Preferably at least 60%, more preferably at least 70%, even more preferably at least 80%, most preferably at least 90%.

According to a preferred embodiment of the present invention, a birefringent interface may be formed between the plate-like polymer (first component) and the substrate (second component) forming the core layer. Specifically, in a reflective polarizer including a polymer inside the substrate, the magnitude of the substantial coincidence or mismatch of the refractive indices along the X, Y, and Z axes in the space between the substrate and the plate-shaped polymer is the degree of scattering of the light polarized along the 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 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 substrate along a certain axis substantially matches the refractive index of the plate-shaped polymer, incident light polarized with an electric field parallel to this axis will pass through the polymer without scattering regardless of the size, shape and density of the portion of the polymer. . 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 substrate and the polymer, but the second polarized light (S wave) is transmitted at the birefringent interface formed at the boundary between the substrate and the polymer. Under the influence of this, modulation of light occurs. 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.

Therefore, since the substrate and the plate-shaped polymer may cause a photomodulation effect by forming a birefringent interface, when the substrate is optically isotropic, the plate-shaped polymer may have birefringence and conversely, when the substrate has optically birefringence The polymer may have optical isotropy. Specifically, in-plane birefringence between nX1 and nY1 when the refractive index in the x-axis direction of the polymer is nX1, the refractive index in the y-axis direction is nY1, the refractive index in the z-axis direction is nZ1, and the refractive index of the substrate is nX2, nY2 and nZ2. This can happen. More preferably, at least one of the X, Y, and Z axis refractive indices of the substrate and the polymer may be different. More preferably, when the extension axis is the X axis, the difference in the refractive indices in the Y and Z axis directions is 0.05 or less. 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 a match.

On the other hand, according to a preferred embodiment of the present invention, the total number of layers of the plate-shaped polymer may be 50 to 3000, the plate-shaped polymer forming one layer is 30 to 1,000, the layer spacing between each layer is 0.01 ~ 1.0 μm. In addition, the separation distance between adjacent plate-shaped polymer forming one layer may be up to 0.01 ~ 1.0㎛. In addition, the short axis length of the longitudinal cross-section of the plate-shaped polymer may be 0.01 ~ 1.0㎛, the long axis length of the longitudinal cross section of the longitudinal direction may be 100 ~ 17,000㎛. On the other hand, the above-described layer spacing, number of layers, separation distance, long and short length may be appropriately adjusted according to the aspect ratio and the desired light wavelength of the present invention.

Meanwhile, in the present invention, the thickness of the core layer is 20 to 180 μm, and the thickness of the skin layer may be 50 to 300 μm, but is not limited thereto.

Next, the manufacturing method of the reflective polarizer in which the polymer of this invention is disperse | distributed is demonstrated.

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 used without limitation as long as the polymer is dispersed in the second component forming the substrate and used in a reflective polarizer in which a conventional polymer is dispersed. 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, and preferably, polyethylene naphthalate (PEN) or copolyethylene naphthalate (co-PEN). ), Polyethylene terephthalate (PET), polycarbonate (PC), polycarbonate (PC) alloy, polystyrene (PS), heat-resistant polystyrene (PS), polymethyl methacrylate (PMMA), polybutylene terephthalate (PBT) ), Polypropylene (PP), polyethylene (PE), acrylonitrile butadiene styrene (ABS), polyurethane (PU), polyimide (PI), polyvinyl chloride (PVC), styrene acrylonitrile mixture (SAN) Ethylene vinyl acetate (EVA), polyamide (PA), polyacetal (POM), phenol, epoxy (EP), urea (UF), 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, and preferably, polyethylene terephthalate (PET), polycarbonate (PC), polycarbonate (PC) alloy, and 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 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 5:95 to 95: 5. 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, (2) to form two or more islands-in-the-sea composites in which a plurality of first components are dispersed inside the second component, and each island-in-the-sea composites reflects a shear wave (S wave) of a desired wavelength. The first component and the second component transferred from the extruder are introduced into the plurality of islands-in-sea type extrusion molds to form two or more islands-in-sea composites having different average optical thicknesses of the first components. 10 and 11 are perspective views showing the coupling structure of the distribution plate of the island-in-the-sea extrusion mold which can be used in the present invention. The first mold distribution plate S1 positioned at the upper end of the island-in-the-sea extrusion mold may have 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 component introduced through the first component supply paths 52 and 53 is branched along the flow path to the first

component supply paths

59, 60, 63, and 64 formed in the third detention distribution plate S3, respectively. Transferred. Similarly, the second components introduced through the second

component supply paths

54, 55, 56 are second

component supply paths

57, 58, 61, 62, 65, 66 formed in the third detention distribution plate S3, respectively. Branched along the flow path and transported. The polymers that have passed through the third detention distribution plate S3 are transferred to the fourth detention distribution plate S4 located below. The first components introduced through the first

component supply paths

59, 60, 63, and 64 are spread out into the first component supply paths 69 formed in the fourth detention distribution plate S4, respectively, The second component introduced through the

component supply paths

57, 58, 61, 62, 65, and 66 is formed in the upper and lower ends of the first component supply paths 69 along the flow path. It is injected into). At this time, the number of layers of the first component included in the island-in-the-sea composite flow is determined according to the number of vertical layers n of the first component supply passages 69. For example, when the number of vertical layers is 50, the number of layers of the first component included in the first island-in-the-sea composite product is 50. In the fourth mold distribution plate S4, the number of island component layers may be 25 or more, more preferably 50 or more, even more preferably 100 or more, and most preferably 150 or more. Subsequently, in the fifth mold distribution plate S5, the first component is infiltrated between the dispersed first components to form an island-in-the-sea composite flow in which the first component is dispersed in the second component. It discharges through the discharge port 70 of the 6th metal distribution board S6. Meanwhile, FIGS. 10 and 11 are examples of island-in-the-sea detention distribution plates that may be used in the present invention, and the number, structure, and detention of detention distribution plates for manufacturing island-in-the-sea composites in which the first component is dispersed in the second component. It is obvious to those skilled in the art to appropriately design and use the size, shape and the like of the holes. Preferably, the diameter of the detention hole in the island component supply passage may be 0.17-5 mm, but is not limited thereto.

On the other hand, as the number of layers of the island component supply passage in the fourth mold distribution plate increases, a degree of conduction between the island components (first component) may occur. In order to prevent this, the island component supply passage may be partitioned as shown in FIG. 12, and the sea

component supply passages

71 and 72 may be formed on the partition passage so that the sea component may penetrate smoothly between the island components. As a result, even if the number of layers in the island component supply path increases, the degree of conduction between the island components (the first component) included in the final substrate may be minimized. On the other hand, it is also possible to form a separate island-in-the-sea composite composite flow path, which is interpreted as a plurality of integrated island-in-the-sea extrusion molds. As a result, the present invention includes not only a plurality of islands-in-the-sea extrusion molds, but also ones that are integrally formed to produce a plurality of islands-in-sea composites.

In addition, in FIG. 10, the arrangement of the island component supply paths of the fourth mold distribution plate may be arranged in a straight line as shown in FIG. 13. However, in order to minimize the bonding and to further disperse the island components in the substrate, FIGS. Likewise, the island component supply path can be arranged in a zigzag type.

Specifically, Figures 15 and 16 is a view of the detention of the island-in-the-sea extrusion mold according to a preferred embodiment of the present invention. Specifically, there are six detention distribution plates of the island-in-the-sea reflective reflector, which are different from the detention distribution plate of FIG. 10 in the fourth detention distribution plate T4 and the fifth detention distribution plate T5. Referring to the difference from FIG. 10, the fourth detention distribution plate T4 of FIG. 15 includes a second component supply passage between the first component supply

passage aggregation units

100, 101, and 102 similarly to FIG. 12. It is divided into a flow path. This allows the second component to soak evenly between the first components.

On the other hand, it is also possible to form a plurality of islands-in-the-sea composite flow through the fourth detention distribution plate (T4) and the fifth detention distribution plate (T5) of FIG. That is, a separate island-in-the-sea complex is manufactured through the

collection parts

100, 101, and 102 through the partitioned island component supply passages of the fourth detention distribution plate T4, and three island-in-the-sea complexes are formed in the detention. Afterwards, you can join one again. To this end, the design and modification of a separate mold distribution plate will be apparent to those skilled in the art, which are included in a plurality of integrated islands-type extrusion molds.

In the present invention, a plurality of islands-in-sea composites comprising the first component dispersed in the second component are formed, and preferably, the number of the islands-in-sea composites is two or more, and more preferably three or more. More preferably, it may be four or more. To this end, as shown in FIG. 17, a plurality of island-in-the-sea extrusion molds capable of forming respective islands-in-sea composite composites may be provided, and a plurality of islands-in-sea extrusion molds may be integrally formed. In this case, it is also possible to form overlapping sea component supply passages, preferably between adjacent extrusion spheres.

In addition, it is too obvious to those skilled in the art to arrange the island-in-the-sea type extrusion molds individually or integrally to form a plurality of island-in-the-sea composites, and to design and arrange the number and structure of the cage distribution plates appropriately for this purpose. For example, when the four islands-type extrusion molds are integrally manufactured to form four islands-in-the-sea composites, the first mold distribution plate may be manufactured as four, which is the number of the fourth cage distribution plates, or the first mold distribution plate. Is common, and it is also possible to branch and supply it to four interruptions.

On the other hand, the plurality of islands-in-the-sea composites each have an optical thickness of the first component, an optical thickness of the second component, the number of layers of the first component, etc. to form different islands-in-the-sea composites to cover a range of wavelength regions of different light. Can be different. To this end, the diameter, cross-sectional area, shape, and / or number of layers of the island component supply passage and / or the sea component supply passage formed in each island-in-the-sea extrusion mold may be different. The reflective polarizer, which is finally manufactured through the spreading and stretching process, has a plurality of groups formed therein, and the plurality of groups have different average optical thicknesses. For this purpose, in consideration of the spreading degree and the stretching ratio of the first components, The diameters of the aforementioned supply paths can be determined.

As described above, optical thickness means n (refractive index) x d (physical thickness). Therefore, if two islands-in-sea composites are formed, if the first component is the same between the islands-in-sea composites, 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 first component and / or the second component included in each island-in-the-sea composite product, the difference in the optical thickness between the islands-in-sea composite products can be derived. Meanwhile, in order to cover the entire visible light region, the average optical thickness of the island-in-the-sea composites should be determined to correspond to various light wavelengths. For example, in order to set an average optical thickness of the first component of the islands-in-the-sea composites so that three composites are composed and respectively correspond to 450 nm, 550 nm, and 650 nm of the wavelength range of light, the first component between islands-in-the-sea composites The average optical thickness of can differ by at least 5% or more, more preferably by 10% or more. Through this, it is possible to reflect the S-waves in the entire visible light region.

In addition, even in the island-in-the-sea type extrusion mold forming one island-in-the-sea composite flow, the diameter, cross-sectional area, shape, etc. of the island component supply passage and / or the sea component supply passage may be the same or different. Furthermore, the optical thickness of the first components forming the same island-in-the-sea composite flow 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 first components of the first islands-in-the-sea composite is 100 nm, the first components forming the same first islands-in-the-sea composite will have an optical thickness variation within approximately 20%. Can be. Meanwhile, the wavelength and the optical thickness of the light are defined according to the following Equation 1.

[Relationship 1]

λ = 4nd

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. The above-described optical thickness deviation is achieved by giving a deviation to the diameter, cross-sectional area, etc. of the island-like extrusion mold in one island-in-the-sea extrusion mold, or the natural minute pressure distribution during the spreading process even if the island component feeding path has the same diameter. The difference can be achieved naturally.

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 having a different discharge amount in order to have a different average optical thickness between islands The first pressing means may further include the step of discharging each different island-in-the-sea extrusion mold. Specifically, FIG. 18 is a schematic view including a first pressurizing means to form two islands-in-the-sea composite flows, in which a first component conveyed from an extruder (not shown) includes the plurality of first pressurizing means 130 and 131. And supplied separately to the islands-in-the-sea type extrusion holes 132 and 133 in 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 each of the island-

like extrusion mold

132, 133 has the same specification (when the shape diameter of the island component supply path, etc. are the same). The average optical thicknesses of the first components of the first island-in-the-sea composite and the second island-in-the-sea composites formed therethrough may be different. When the first pressurizing means (130. 131) each have a different discharge amount, the area of the first compound formed in the first composite stream and the second composite stream produced through the island-in-the-

sea extrusion molds

132 and 133 connected thereto The difference in area is caused by different discharge amounts, resulting in a difference in optical thickness between composite flows.

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.

Meanwhile, one first pressing means transfers the first component to the two islands-in-the-sea extrusion molds, and the two islands-in-the-sea composites formed from the two islands-in-the-sea extrusion molds are laminated to form one island-in-the-sea composites. It is also possible for one group to be formed. In this case, four groups may be formed through the four first component pressing means and the eight island-in-the-sea extrusion molds. It is also possible for one first pressing means to transfer the first component to three or more islands-in-sea extrusion molds.

According to another preferred embodiment of the present invention, the second component conveyed from the extrusion section between the steps (1) and (2) is a plurality of having a different discharge amount in order to have a different average optical thickness between islands-in-the-sea composites Each of the second islands may be discharged to different islands-in-sea extrusion molds. Specifically, FIG. 19 is a schematic view of including two second pressing means to form two islands-in-the-sea composite flows, in which a second component conveyed from an extruder (not shown) includes the plurality of second pressing means 140, Branched to 141 and supplied separately to the islands-in-the-sea extrusion-type extrusion holes 142 and 143 in respective second pressurizing means 140 and 141. At this time, the second pressing means (140, 141) has a different discharge amount from each other through this, each island-

like extrusion mold

142, 143 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 island-in-the-sea composites and the second island-in-the-sea composites formed through them, that is, the thickness of the substrate (core layer) may be different. To this end, the discharge amount of the second

pressing means

140, 141 may be preferably 1 to 100 kg / hr, but is not limited thereto.

Meanwhile, one second pressing means transfers the second component to the two islands-in-the-sea extrusion molds, and the two islands-in-the-sea composites formed from the two islands-in-the-sea extrusion molds are laminated to form one island-in-the-sea composites. It is also possible for one group to be formed. In this case, four groups may be formed through the four second component pressing means and the eight island-in-the-sea extrusion molds. It is also possible for one second pressing means to transfer the second component to three or more islands-in-sea extrusion molds.

According to another preferred embodiment of the present invention, between the steps (1) and (2), the step of discharging the second component conveyed from the extrusion unit through the second pressing means to each different island-in-the-sea extrusion mold It may further include. 20 is a schematic view including one second pressurizing means for forming two islands-in-the-sea composite flows, in which a second component conveyed from an extruder (not shown) is supplied to the second pressurizing means 150 and The plurality of islands-in-the-

sea extrusion molds

151 and 152 are separately supplied. The average optical thickness of the second component of the first island-in-the-sea composite and the second island-in-the-sea composites formed thereon may be the same, in which case the first pressurizing means for supplying the first component It can arrange | position in plural and can adjust so that the average optical thickness of the 1st component contained in each island-in-the-sea complex may differ.

In the next step (3), the two or more islands-in-the-sea composites are laminated together to form a core layer. Specifically, FIG. 21 is a schematic view showing the lamination portion of the island-in-the-sea composites, and the core layer 165 by laminating the plurality of island-in-the-

sea composites

161, 162, 163, and 164 manufactured through each island-in-the-sea extrusion mold. ) To form. On the other hand, the lamination step may be carried out in a separate place or when using an integrated island-in-the-sea type extrusion mold may be laminated to one through a separate aggregated distribution plate. In addition, when the number of islands-in-sea composites is large, it is also possible to carry out a multi-stage lamination in the form of laminating some islands-in-sea composites first and then laminating them in order to facilitate lamination. Meanwhile, the skin layer component may also be laminated simultaneously or sequentially with the core layer in the lamination portion.

Meanwhile, a separate prespreading step may be further performed to facilitate the spreading of the first component, which will be described later, between steps (2) and (3) or between steps (3) and (4). .

Next, as the step (4), at least one surface of the laminated core layer is laminated with the skin layer component transferred from the extruder. 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, as described above, when the skin layer components are simultaneously laminated in the lamination part of step (3), this step may be omitted.

Next, in step (5), the first component of the core layer in which the skin layer is laminated induces spreading in the flow control unit to form a plate-like shape. Specifically, FIG. 22 is a cross-sectional view of a coat-hanger die, which is a kind of preferred flow control unit that may be applied to the present invention, and FIG. 23 is a side view. Through this, the spreading degree of the core layer may be appropriately adjusted so that the shape of the vertical cross section in the longitudinal direction of the first component may have a plate shape. In FIG. 22, since the core layer in which the skin layer transferred through the flow path is laminated spreads widely from side to side in the coat-hanger die, the first component included therein also spreads from side to side. In addition, as shown in the side view of FIG. 23, the coat hanger die spreads from side to side, but has a structure of decreasing vertically, so that the skin layer is spread 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 ℃. On the other hand, the degree of spreading may be affected by the compatibility of the first component and the second component, etc. In order to have excellent spreadability, it is preferable to use CO-PEN as the first component and PEN as the second component. In addition, the degree of spreading can be controlled by appropriately polymerizing monomers constituting CO-PEN, for example, dimethyl-2,6-naphthalene dicarboxylate, dimethyl terephthalate, ethylene glycol and cyclohexanedimethanol (CHDM). have. The flow control part may be a T-die or a coat-hanger die of a manifold type so that the first component may form a plate shape, but the present invention is not limited thereto, and induces spreading of the core layer to guide the first component to the plate shape. Anything that can be used can be used without limitation.

On the other hand, the plate-shaped aspect ratio is a ratio of the short axis length to the long axis length relative to the vertical section is 1/200 or less, 1/300 or less, 1/500 or less. It may be 1/1000 or less, 1/2000 or less, 1/5000 or less, 1/10000 or less, or 1/20000 or less. If the aspect ratio is greater than 1/200, it is difficult to achieve the desired optical properties even when the aspect ratio is reduced through elongation of the polarizer. In particular, when the aspect ratio induces spreading of more than 1/200 and then adjusts the aspect ratio of the final first component through a high draw ratio of 6 times or more, the area of the first component is smaller than that of the second component, so as to form a gap between the first components. Due to the light leakage phenomenon, there is a problem of optical properties deterioration.

In the manufacturing method of the present invention, a plurality of islands-in-sea composites having different average optical thicknesses of the first component are prepared using a plurality of islands-in-sea extrusion molds and laminated in a molten state so that a separate adhesive layer and / or a protective layer (PBL) are used. Do not 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 can significantly reduce the manufacturing cost. In addition, the reflective polarizer manufactured by the manufacturing method of the present invention includes a very small number of birefringent polymers in the same area compared to the reflective polarizer including a birefringent polymer because the polymer inside the substrate has a plate-like shape. In this case, not only excellent optical properties can be achieved but also a plurality of groups having different average optical thicknesses are formed, so that all S waves in the visible wavelength range can be reflected.

According to a preferred embodiment of the present invention, after the step (5), (6) cooling and smoothing the polarizer induced by the spread transferred from the flow control unit, (7) stretching the polarizer after the smoothing step ; And (8) heat setting the stretched polarizer.

First, as a step (6), 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 first component Stretching further reduces the aspect ratio. Therefore, in order to adjust the optical thickness by inducing the aspect ratio of the plate-shaped shape of the first component desired in the final reflective polarizer, it may be appropriately set in consideration of the diameter, spreading induction condition and elongation ratio of the island-like extrusion hole in the island-like extrusion hole. will be. 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 may be performed in the longitudinal direction of the first component. 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 (8). 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 and aspect ratio to be targeted between groups is determined, the reflective polarizer of the present invention can be manufactured by appropriately controlling the specifications of the island-in-the-sea extrusion mold, the specification and the draw ratio of the flow control unit, etc. It is.

According to a preferred embodiment of the present invention, an apparatus for manufacturing a reflective polarizer in which a polymer is dispersed, comprising a core layer having a plurality of first components dispersed therein and a skin layer formed on at least one surface of the core layer. At least three extrusion parts into which the first component, the second component and the skin layer component are separately put; The extrusion component in which the first component is injected is formed to form a plurality of islands-in-the-sea composites in which the first component is dispersed inside the second component, and each island-in-the-sea composite compound reflects an S wave of a desired wavelength. And a plurality of islands-in-sea type extrusion molds in which two or more islands-in-sea type extrusion molds are formed by injecting the first component and the second component transferred from the extruded part into which the second component is injected to form two or more islands-in-sea composites having different average optical thicknesses of the first components. Block portion; A collection block unit for laminating two or more islands-in-the-sea composites transferred from the spin block unit into one to form a core layer; A feed block portion in communication with the extruder into which the skin layer component is injected and laminating the skin layer on at least one surface of the core layer transferred from the collection block; And a flow control unit for inducing spreading so that the first component of the core layer on which the skin layer transferred from the feed block unit is laminated forms a plate shape.

24 is a schematic diagram of an apparatus for manufacturing a reflective polarizer in which a polymer is dispersed according to 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 part 220 is in communication with the spin block portion (C) comprising four islands-type extrusion mold (223, 224, 225, 226). At this time, the first extrusion unit 220 supplies the first island-

like extrusion molds

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 island-

like extrusion molds

223, 224, 225, and 226 included therein. Four islands-in-the-

sea extrusion molds

223, 224, 225, and 226 produce four islands-in-the-sea composites with the first component dispersed within the second component and having different average optical thicknesses. The four islands-in-the-

sea extrusion molds

223, 224, 225, and 226 may be the island-in-the-sea extrusion molds shown in FIG. 10 or 15. In addition, although four islands-type extrusion molds are exemplified, it is naturally included in the scope of the present invention that one integrated islands-type extrusion mold can be used. The four islands-in-the-sea composites manufactured through the four islands-in-the-

sea extrusion molds

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 island-in-the-sea type extrusion mold, the island-in-the-sea composites may be laminated in the form of a collective mold inside the island-in-the-sea 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 to form a plate shape. Preferably the flow control part may be a T-die or a coat-hanger die. On the other hand, when the skin layer is laminated with the core layer at the same time, the third extruded portion 222 may be in communication with the collection block portion 227, in which case the feed block portion 228 may be omitted.

25 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. 24, 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 island-in-the-sea 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 island-in-the-sea type extrusion holes 241, 242, 243, and 244. On the other hand, there is only one second pressurizing means and it is also possible to discharge it to the plurality of islands-type extrusion mold (241, 242, 243, 244). Four islands-in-the-

sea extrusion molds

241, 242, 243, and 244 produce four islands-in-the-sea composites with the first component dispersed within the second component and having different average optical thicknesses. The first pressing means, the second pressing means, and the plurality of island-in-the-sea extrusion molds form the spin block portion C.

26 is a schematic diagram of an apparatus for manufacturing a reflective polarizer in which a polymer is dispersed according to another preferred embodiment of the present invention. A brief description of the difference from FIG. 25 will be given in that a multistage lamination is performed using eight islands-in-the-sea extrusion molds instead of four islands-in-the-sea extrusion molds in order to produce a reflective polarizer having four groups. Specifically, the first pressurizing means 233 discharges the first component to the two islands-in-the-

sea extrusion molds

250 and 251. The second pressurizing means 234 also discharges the first component to the two islands-in-the-

sea extrusion molds

250 and 251. The two islands-in-the-sea

type extrusion molds

250 and 251 have the same average optical thickness between islands-in-sea composite flows because the first component and the second component are transferred through the same first pressing means and the second pressing means. In this way, eight islands-in-the-sea composites are formed, and these islands-in-the-sea composites have the same average optical thickness by two. The two islands-in-the-sea composites having the same average optical thickness are respectively laminated at the

first laminations

258, 259, 260, and 261 to form four islands-in-the-sea composites, and the four islands-in-the-sea composites are the second sum. It is laminated at branch 262 to form one core layer.

Meanwhile, in FIG. 26, one first pressing means transfers the first component to the two islands-in-the-sea extrusion molds, but it is apparent to those skilled in the art that the first component can be transferred to the two or more islands-in-sea 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. 27 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. 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. The first component was transferred to four first pressurizing means (Kawasaki gear pumps) and the second component was also transferred to four second pressurizing means (Kawasaki gear pumps). The discharge amounts of the first pressurization means are respectively 10.5 kg / h, 5.3 kg / h, 6.9 kg / h, and 8.9 kg / h, and the discharge amounts of the second pressurization means are respectively 10.5 kg / h and 5.3 kg / h. , 6.9 kg / h, 8.9 kg / h. Four composites having different average optical thicknesses were prepared using four island-in-the-sea extrusion molds as shown in FIG. 15. Specifically, a first composite flow was prepared by adding the first first component transferred from the first pressing means and the first second component transferred from the second pressing means to the first island-in-the-sea extrusion mold. In this order, up to the fourth composite product was prepared. Among the first to fourth island-in-the-sea extrusion molds, the number of the island component layers of the fourth mold distribution plate T4 is 96, the diameter of the detention hole in the island component supply passage is 0.17 mm, and the total number of four island component supply passages is 9300 each. The diameter of the discharge port of the sixth mold distribution plate was 15 mm x 15 mm. The island-in-the-sea extrusion mold used the same mold. Four composites discharged through the four islands-in-the-sea extrusion molds 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. The skin layer is formed such that the aspect ratio of the first composite flow is 1/13500, the aspect ratio of the second composite flow is 1/25000, and the aspect ratio of the third composite flow is 1/19500, and the aspect ratio of the fourth composite flow is 1/15900. The layer polymer was induced to spread in the coat hanger dies of FIGS. 21 and 22, which corrected for flow velocity and pressure gradient. 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, 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. As a result, the long axis length of the first component was not changed, but the short axis length was reduced. Thereafter, heat setting was performed through an IR heater at 180 ° C. for 2 minutes to prepare a reflective polarizer in which the polymer as shown in FIG. 7 was dispersed. 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. The aspect ratio of the plate A layer was 1/101000, the number of layers was 96 layers, the short axis length (thickness direction) was 100 nm, the major axis length was 10.1 mm, the average optical thickness was 164 nm, and the optical thickness deviation was about 20%. The plate aspect ratio of layer B was 1/184000 aspect ratio, the number of layers was 96 layers, the short axis length (thickness direction) was 54.9 nm, the major axis length was 10.1 mm, the average optical thickness was 90 nm, and the optical thickness deviation was about 20%. The aspect ratio of the C layer was 1/148000, the number of layers was 96 layers, the short axis length (thickness direction) was 68.3 nm, the major axis length was 10.1 mm, the average optical thickness was 112 nm, and the optical thickness deviation was about 20%. The plate aspect ratio of the D layer was 1/120000, the number of layers was 96 layers, the short axis length (thickness direction) was 84 nm, the major axis length was 10.1 mm, the average optical thickness was 138 nm, and the optical thickness deviation was about 20%. Core layer thickness is 59 micrometers, and skin layer thickness is 170.5 micrometers on upper and lower surfaces.

The process was carried out as in Example 1. Specifically, PEN having a refractive index of 1.65 as the first component and dimethyl terephthalate and dimethyl-2,6-naphthalene dicarboxylate as the second component were mixed in an molar ratio of 88:12. : 90 wt% of co-PEN and polycarbonate having a refractive index of 1.62 at a molar ratio of 2 and a refractive index of 1.58 polymerized with 10 wt% of polycyclohexylene dimethylene terephthalate (PCTG) as a skin layer component. The polycarbonate alloy was charged into the first extrusion section, the second extrusion section and the third extrusion section, respectively. Under the same conditions as in Example 1, the aspect ratio of the first composite flow was 1/8670, the aspect ratio of the second composite flow was 1/15730, the aspect ratio of the third composite flow was 1/12780, and the aspect ratio of the fourth composite flow was Spreading was performed on the coat-hanger die to 1/10320. Thereafter, a reflective polarizer in which the polymer as shown in FIG. 7 was dispersed was manufactured in the same manner as in Example 1. 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 1.62. The aspect ratio of the plate A layer was 1/52000, the number of layers was 96 layers, the short axis length (thickness direction) was 100 nm, the major axis length was 5.2 mm, the average optical thickness was 164 nm, and the optical thickness deviation was about 20%. The aspect ratio of the plate B was 1/94370, the number of layers was 96 layers, the short axis length (thickness direction) was 55.1 nm, the major axis length was 5.2 mm, the average optical thickness was 90.4 nm, and the optical thickness deviation was about 20%. The aspect ratio of the C layer was 1/76700, the number of layers was 96 layers, the short axis length (thickness direction) was 67.8 nm, the major axis length was 5.2 mm, the average optical thickness was 111.2 nm, and the optical thickness deviation was about 20%. The plate aspect ratio of the D layer was 1/61900, the number of layers was 96 layers, the short axis length (thickness direction) was 84 nm, the major axis length was 5.2 mm, the average optical thickness was 138 nm, and the optical thickness deviation was about 20%.

The process was carried out as in Example 1. Specifically, PEN having a refractive index of 1.65 as the first component and 70 wt% of polycarbonate and polycyclohexylene dimethylene terephthalate (PCTG) as the second component have a refractive index of 1.59. First extrusion of a polycarbonate alloy having a refractive index of 1.58, in which 90% by weight of polycarbonate and 10% by weight of polycyclohexylene dimethylene terephthalate (PCTG) were polymerized as a polycarbonate alloy and skin layer component It injected | thrown-in to the part, 2nd extrusion part, and 3rd extrusion part. Under the same conditions as in Example 1, the aspect ratio of the first composite flow was 1/250, the aspect ratio of the second composite flow was 1/455, the aspect ratio of the third composite flow was 1/366, and the aspect ratio of the fourth composite flow was Spreading was performed on the coat-hanger die to reach 1/297. Thereafter, a reflective polarizer in which the polymer as shown in FIG. 7 was dispersed was manufactured in the same manner as in Example 1. 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 1.59. The aspect ratio of the plate A layer was 1/1500, the number of layers was 96 layers, the short axis length (thickness direction) was 100 nm, the major axis length was 0.15 mm, the average optical thickness was 164 nm, and the optical thickness deviation was about 20%. The plate aspect ratio of layer B was 1/2780, the number of layers was 96 layers, the short axis length (thickness direction) was 55 nm, the major axis length was 0.15 mm, the average optical thickness was 90.2 nm, and the optical thickness deviation was about 20%. The aspect ratio of the C layer was 1/2170, the number of layers was 96 layers, the short axis length (thickness direction) was 68.3 nm, the major axis length was 0.15 mm, the average optical thickness was 112 nm, and the optical thickness deviation was about 20%. The plate aspect ratio of the D layer was 1/1770, the number of layers was 96 layers, the short axis length (thickness direction) was 84 nm, the major axis length was 0.15 mm, the average optical thickness was 138 nm, and the optical thickness deviation was about 20%.

Comparative Example 1

A reflective polarizer for 32-inch LCDs including 25000 birefringent fibers made of PEN, the first component having a diameter of 0.158 μm, was prepared inside the CO-PEN substrate, which is the second component.

Comparative Example 2

The process was carried out as in Example 3. Specifically, PEN having a refractive index of 1.65 as the first component and 70 wt% of polycarbonate and polycyclohexylene dimethylene terephthalate (PCTG) as the second component have a refractive index of 1.59. First extrusion of a polycarbonate alloy having a refractive index of 1.58, in which 90% by weight of polycarbonate and 10% by weight of polycyclohexylene dimethylene terephthalate (PCTG) were polymerized as a polycarbonate alloy and skin layer component It injected | thrown-in to the part, 2nd extrusion part, and 3rd extrusion part. In the intermediate conditions, the discharge amounts of the first pressurizing means are 5.2 kg / h, 2.6 kg / h, 3.4 kg / h, 4.5 kg / h, respectively, in the same state as in Example 1, and the discharge amounts of the second pressing means are respectively Boulevards are 10.5 kg / h, 5.3 kg / h, 6.9 kg / h and 8.9 kg / h. Under the same conditions as in Example 1, the aspect ratio of the first composite flow was 1/64, the aspect ratio of the second complex flow was 1/117, the aspect ratio of the third composite flow was 1/92, and the aspect ratio of the fourth composite flow was 1. Spreading was performed on the coat-hanger die to be / 75. Thereafter, a reflective polarizer in which the polymer as shown in FIG. 7 was dispersed was manufactured by the same process as in Example 3. 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 1.59. The aspect ratio of the plate A layer was 1/380, the number of layers was 96 layers, the short axis length (thickness direction) was 100 nm, the major axis length was 0.038 mm, the average optical thickness was 164 nm, and the optical thickness deviation was about 20%. The plate aspect ratio of the B layer was 1/700, the number of layers was 96 layers, the short axis length (thickness direction) was 55 nm, the major axis length was 0.038 mm, the average optical thickness was 90.2 nm, and the optical thickness deviation was about 20%. The aspect ratio of the C layer was 1/556, the number of layers was 96 layers, the short axis length (thickness direction) was 68.3 nm, the major axis length was 0.038 mm, the average optical thickness was 112 nm, and the optical thickness deviation was about 20%. The plate aspect ratio of the D layer was 1/452, the number of layers was 96 layers, the short axis length (thickness direction) was 84 nm, the major axis length was 0.038 mm, the average optical thickness was 138 nm, and the optical thickness deviation was about 20%.

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 2 to 3 and Comparative Examples 1 to 2 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	85%	88%	7%	83%	88%	8%
Example 2	97	80%	88%	10%	78%	88%	11%
Example 3	88	66%	88%	18%	65%	88%	19%
Comparative Example 1	65	43%	89%	35%	35%	89%	43%
Comparative Example 2	80	56%	89%	25%	52%	89%	28%

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.

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

In order to transmit the first polarized light irradiated from the outside and reflect the second polarized light, a plurality of plate-shaped polymers dispersed in the substrate and having an aspect ratio that is a ratio of the short axis length to the long axis length based on the vertical cross section of the polarizer are 1/1000 or less Wherein the plurality of plate-shaped polymers differ in refractive index in at least one axial direction from the substrate, and the substrate is elongated in at least one axial direction, The plurality of plate-shaped polymers each form a group to reflect a shear wave (S wave) of a desired wavelength, wherein the plurality of groups are formed, and a polymer including a core layer having a different average optical thickness of the plate-shaped polymers between groups is dispersed. Reflective polarizer.
The method of claim 1, wherein the difference between the refractive index of the base material and the polymer is a reflective polarizer dispersed in the polymer, characterized in that the difference in the stretched axial refractive index is greater than the difference in the refractive index of the other axial direction.
The reflective polarizer of claim 1, wherein a polymer including a skin layer integrally formed on at least one surface of the core layer is dispersed.
4. The reflective polarizer with dispersed polymer according to claim 3, wherein an adhesive layer is not formed between the core layer and the skin layer.
The reflective polarizer of claim 1, wherein the plurality of polymers form four groups to reflect light in four wavelength bands.
The method of claim 1,

Optically dispersed reflective polarizer of claim 1, wherein the optical thickness of the polymers included in the same group has a thickness deviation within 30% of the average optical thickness.
6. The reflective polarizer of claim 5, wherein the four reflection bands include wavelength bands of 350 nm, 450 nm, 550 nm, and 650 nm.
The method of claim 1, wherein the plurality of groups differ by at least 5% in average optical thickness of the polymers.
The longitudinal cross-section of the polymer of claim 1, wherein the plurality of groups form a plurality of spaced apart layers based on the longitudinal cross-section of the polymer, wherein the plurality of polymers included in one group are disposed spaced apart from each other and the longitudinal cross-section of the polymer Reflective polarizer with a dispersed polymer, characterized in that to form at least 50 or more spaced apart layer.
The reflective polarizer in which the polymer is dispersed according to claim 1, wherein an aspect ratio of the short axis length to the long axis length is 1/5000 or less based on the vertical cross section of the plate-shaped polymer.
The reflective polarizer of claim 1, wherein an aspect ratio of the short axis length to the long axis length is 1/10000 or less based on the vertical cross section of the plate-shaped polymer.
The reflective polarizer of claim 1, wherein an aspect ratio of the short axis length to the long axis length is 1/30000 or less based on the vertical cross section of the plate-shaped polymer.
The reflective polarizer with dispersed polymer according to claim 1, wherein the polymer satisfying the aspect ratio is 50% or more among the plurality of polymers.
The reflective polarizer with dispersed polymer according to claim 1, wherein an adhesive layer is not formed between the groups.
10. A reflective polarizer with dispersed polymer according to claim 9, wherein the average distance d 1 of adjacent polymers forming the same layer is smaller than the average distance d 2 of indented polymers forming different layers.
The reflective polarizer of claim 1, wherein the maximum value of the spacing between adjacent polymers forming the same group is smaller than the maximum value of the spacing between adjacent polymers between adjacent groups.
The reflective polarizer having a polymer dispersed therein according to claim 1, wherein the short axis length of the vertical section of the polymer is 0.01 to 1.0 mu m.
A backlight unit comprising the reflective polarizer of claim 1.