TW201106029A - Polarizing element and display device using the same - Google Patents

Abstract

The present invention is to provide a polarizing element capable of expressing excellent polarizing and scattering properties through a sample method. The polarizing element is obtained that the formed sheet by melting and mixing polycarbonate-based resin and transparent resin is uniaxially drawn, and dispersion phase constituted by transparent resin of particle shape is dispersed in continual phase constituted by polycarbonate-based resin. The absolute value of refractive index difference between drawing direction of continual phase and perpendicular direction to the drawing direction of the continual phase is less than 0.05, and the absolute value of refractive index difference between drawing direction of dispersion phase and perpendicular direction to the drawing direction of the dispersion phase is 0.05 and more; further, the difference of refractive index between the continual phase and dispersion phase relative to straight line polarizing is different; the reflection index of polarizing in the direction parallel to drawing direction is 30% and more.

Description

[Technical Field] The present invention relates to a polarizing element having light diffusibility and polarization, and a display device including the same (surface light source device, transmissive or reflective liquid crystal display device, etc.) ). [Prior Art] In the liquid crystal display device, an iodine-based or dye-based absorption type polarizing plate is generally used. Therefore, the brightness of the display surface is less than or equal to half the brightness of the light source such as external light or illumination light. Further, since two kinds of the above-mentioned absorption type polarizing plates are used on the inner surface of the liquid crystal panel, the brightness of the light source is actually reduced to 30 to 40%. Therefore, in order to obtain higher brightness, an attempt is made to change the polarization to compensate for this disadvantage. The method of polarized light conversion may be, for example, a method such as a beam splitter or the like, or a polarization conversion method using a characteristic of a circularly polarized liquid of a cholesteric liquid crystal. However, in the method of sputum, the polarization depends on the angle or wavelength, while lacking in lightness or compactness. In the case of using a cholesteric liquid crystal, if the full wavelength is to be covered, it is necessary to form the liquid crystal into a plurality of layers having different spiral pitches, which makes the production of the liquid crystal complicated and costly. In addition, it is known that a polarizing sheet of a laminated optical element, a polarizing sheet of a laminated optical element, a film containing a polyester resin, and the like are laminated on both sides of a flat element composed of a calcining material such as calcite, and a liquid crystal and a polymer are used. The method of the complex, etc., but the method of making the system is not only complicated but also expensive, and cannot be popularized.

[S-4-201106029 On the one hand, it has also been proposed to use a scattering sheet which is dispersed in a granular form in a dispersed phase having a refractive index different from the continuous phase in the continuous phase as a method of using a polarizing element. Japanese Laid-Open Patent Publication No. Hei 9-297204 (Patent Document 1) discloses that an inorganic scattering particle having an aspect ratio of 1 or more is dispersed in a resin or a polymer anisotropic scattering element having different refractive indices. However, in the case where the scattering particles are arranged in a certain direction, voids between the polymer and the inorganic particles are liable to occur, and the production cannot be stably performed. Further, in the processing method in which it is difficult to generate voids, a method of performing ultraviolet curing by using inorganic particles in a polymer by calender processing using a roll is used, but it is limited by the polymer to be used. In the first polymer containing an aromatic polyester resin, a second polymer containing a crystalline polypropylene resin is dispersed in the first polymer disclosed in Japanese Patent No. 4,87,7,84 (Patent Document 2). The sheet is stretched to produce a microvoid. However, in the method of generating circular micropores around the dispersion, it is difficult to control the polarization characteristics of the sheet due to various geometrical configurations of the interface. Japanese Patent Publication No. 2000-506990 (Patent Document 3) discloses an optical body comprising: a first phase having at least a complex refractive index of about 〇. 5; and a second phase disposed at the first In the phase, the refractive index difference from the first phase is greater than about 0.05 along the first axis, and the optical body is less than about 0,05 along the second axis orthogonal to the first axis. The diffuse reflectance of the entire second phase and at least one kind of polarized light with respect to the electromagnetic wire are at least about 30% along at least one axis. In this document, in the first and second polymer combinations 201106029, a combination of 2,6-polyethylene naphthalate ethyl ester and polymethyl methacrylate or syndiotactic polystyrene is described. Further, it has been described that in order to improve the adhesion between the phases, a small amount of naphthalene dicarboxylic acid can be used, and in order to form voids, a remelting agent is used. However, when a thin layer of a polymer constituting the second phase is stretched in the polymer constituting the first phase, the bonding strength between the two polymers is weak, and the continuous phase accompanying stretching is A small amount of voids are generated between the dispersed phases, and the sheet cannot be stably produced. Further, although the example of using polystyrene styrene methacrylate as a remelting agent is described, even if a remelting agent is blended, the viscosity of the terminal is rapidly increased and gelled, and stability and smooth appearance are not obtained. Excellent sheet. In order to eliminate such a problem, a polarizing element is disclosed in Japanese Laid-Open Patent Publication No. 2003-075643 (Patent Document 4), which is a polarizing element, which has excellent scattering characteristics and polarization characteristics, and which does not cause voids. It comprises an element for stretching a sheet, wherein the dispersed phase containing the second transparent resin is dispersed in a granular form in a continuous phase containing the first transparent resin, and the refractive index in the two phases in the stretching direction and the vertical direction of the sheet The difference is different, and there is substantially no gap between the two phases. It is described in the literature that a second transparent resin having an epoxy group or a mutual solvent having an epoxy group is blended with respect to the first transparent resin containing a polyester resin. However, even if the resin composition has a special method such as stretching or rolling mill requiring a high magnification of 4 times or more, the polarizing element stretched to 4 times or more is liable to be broken. Further, in the case where a special method such as rolling is not used, it is necessary to stretch at a high magnification from 201106029, so that a general stretching machine cannot be used. Japanese Laid-Open Patent Publication No. 2008- 1295 (Patent Document 5) discloses a scattering type polarizing element having a continuous phase composed of a polyester resin (A) and a polystyrene resin (B). The dispersed phase is composed, and the yellowness (YI 値) is in the range of -3 to 3. However, even in the polarizing element, in order to increase the brightness, stretching at a high magnification of 4 times or more is required. On the other hand, as long as the draw ratio is 4 times or less, a general-purpose 2-axis stretching apparatus for a polyester and a stretcher apparatus can be used, which is advantageous in terms of convenience. For example, when stretching in the one-axis direction, it is possible to easily form an unstretched sheet from a fine line width to a wide stretch sheet. Further, as for the material to be used, since the expensive polyester resin is used as the continuous phase, the material cost is high and the economy is low. In addition, in terms of an inexpensive material resin, a polyolefin resin, a polymethyl methacrylate resin, a styrene resin, a polycarbonate resin, or the like is generally exemplified, but the refraction due to stretching The change in rate is small and is not suitable for the formation of an anisotropic type of polarizing element in which the continuous phase produces a refractive index. That is, in the case where an inexpensive material is used as the continuous phase, most inexpensive materials have a small change in refractive index, and therefore, in such materials, we seek to perform polarization conversion to obtain higher brightness. However, in the dispersion phase, a soft resin is used in comparison with the continuous phase, and the tensile deformation is a rugby ball shape or a rod shape, but the deformation stress is small, and the molecular chain is easily aligned and relaxed. Therefore, in the dispersed phase, even if stretched, no large refractive index difference is produced. Therefore, it is unknown that a low-cost material such as polycarbonate 201106029 vinegar is used as a continuous phase polarizing element. PRIOR ART DOCUMENT PATENT DOCUMENT Patent Document 1: Japanese Laid-Open Patent Publication No. Hei No. Hei 9-297204 (Application No. PCT Application No. JP-A No. Hei No. Hei No. Hei No. Hei. Japanese Patent Laid-Open Publication No. 2003-075643 (Patent Application, Examples) Patent Document 5: JP-A-2008-129556 (Patent Application, Paragraph [0024] [Embodiment] The present invention has been made to solve the problems of the present invention. Accordingly, it is an object of the present invention to provide a polarizing element which can exhibit excellent polarizing characteristics and scattering characteristics in a simple manner, and a display device including the polarizing element (surface light source device, A display device such as a liquid crystal display device). Another object of the present invention is to provide a polarizing element which can increase the brightness of a display device even at a low stretching ratio, and a display device including the polarizing element. Another object of the present invention is to provide a polarizing element which is excellent in polarizing characteristics without causing cracks or voids due to stretching, and a display device including the polarizing element. 201106029 Another object of the present invention is to inexpensively and easily manufacture the polarizing element and a display device including the polarizing element. MEANS FOR SOLVING THE PROBLEMS The inventors of the present invention have found that the matric phase (continuous phase) contains a polycarbonate resin and the dispersed phase contains a predetermined transparent resin. When the sheet is stretched by one axis, excellent polarizing characteristics and scattering characteristics can be easily exhibited, and thus the present invention has been completed. That is, the polarizing element of the present invention includes an element in which a dispersed phase containing a transparent resin is dispersed in a granular form in a stretched sheet containing a continuous phase of a polycarbonate-based resin, and the in-plane birefringence of the continuous phase is less than 0.05. The in-plane birefringence of the dispersed phase is 0.05 or more, and the refractive index difference between the continuous phase and the dispersed phase with respect to the linearly polarized light is different in the stretching direction from the perpendicular direction with respect to the stretching direction. In the polarizing element, the absolute 値 of the refractive index difference between the continuous phase and the dispersed phase in the stretching direction is 0.1 to 0.3, and the absolute 値 of the refractive index difference between the continuous phase and the dispersed phase in the vertical direction with respect to the stretching direction is 0.1. the following. The average length of the major axis and the minor axis of the dispersed phase is 0, 8 to 10//m and 0.05 to 0.8 // m, respectively, and the average aspect ratio may be 2 to 200. In the polarizing element of the present invention, the total light transmittance of the linearly polarized light in the vertical direction with respect to the stretching direction is 80% or more, and the reflectance of the linearly polarized light in the direction parallel to the stretching direction (the specular reflection component and the backscattering component) The reflectance) can be 30% or more. The polycarbonate resin may be a bisphenol A type polycarbonate resin having a glass transition temperature of 120 to 160 °C. The dispersed phase may contain a polyester resin (especially a polyalkylene naphthalate system such as a polyethylene naphthalate resin, 201106029). The ratio of the continuous phase to the dispersed phase is about continuous phase/dispersion phase = about 99/1 to 50/50 (weight ratio). The present invention also includes a method of producing a polarizing element by subjecting a sheet formed by melt-mixing a polycarbonate resin and a transparent resin to a single axis. In this method, when the glass transition temperature of the polycarbonate resin is Tg, the temperature may be one-axis stretching to 1.2 to 4 times at a temperature of from T g ° C to (Tg + 80 ° ° C). Further, the heat treatment may be carried out at a temperature higher than the stretching temperature. The present invention also includes a surface light source device and a liquid crystal display device including the polarizing element. Further, in the present specification, the "film" is intended to include a sheet regardless of the thickness. EFFECTS OF THE INVENTION In the present invention, the continuous phase contains a polycarbonate resin, and the sheet in which the dispersed phase contains the predetermined transparent resin is axially stretched, so that excellent polarization characteristics and scattering characteristics can be easily obtained. Further, even at a low draw ratio, the brightness of the display device can be increased, and cracking or voiding due to stretching can be prevented, and the polarizing characteristics can be improved. Further, in the present invention, such an excellent polarizing element can be manufactured inexpensively and simply. [Embodiment] [Polarizing element] The polarizing element of the present invention comprises a stretched sheet in which a dispersed phase containing a transparent resin is dispersed in a granular form in a continuous phase containing a polycarbonate resin. That is, the polarizing element is composed of: a mother body forming the polarizing element

ί S J -ιο 201106029 (matrix) a continuous phase; and a dispersed phase present in the matrix and exhibiting a polarizing function. The interface between the continuous phase and the dispersed phase does not substantially create a void, and the continuous phase and the dispersed phase are combined or adhered. (Continuous phase) The continuous phase system comprises a polycarbonate resin, and in-plane birefringence (absolute enthalpy of the refractive index difference between the stretching direction and the direction perpendicular to the stretching direction) is less than 0.05, for example, 〇 to 0.03, preferably It is from 0 to 0.02, more preferably from 0 to 0.01. In the present invention, the draw ratio can also be suppressed from being low. In particular, in the case of the bisphenol A type polycarbonate resin, the in-plane birefringence is substantially 〇 in the stretching ratio of 3 to 5 times in the conditions of the examples to be described later. Further, the refractive index was measured at a wavelength of 63 3 nm using a prism coupler (manufactured by Metricon Co., Ltd.) as described in the following examples. The polycarbonate resin contains an aliphatic polycarbonate such as an aromatic polycarbonate or a diethylene glycol bisallyl carbonate based on a bisphenol. Among these, an aromatic polycarbonate which is based on a bisphenol is preferable because it is excellent in optical characteristics and inexpensive. Examples of the bisphenols include biphenols such as dihydroxybiphenyl, bisphenol A, bisphenol F, bisphenol AD, bis(4-hydroxymethylphenyl)alkane, and bis(4-hydroxymethylbenzyl) chain. A bis(hydroxyaryl)alkane such as an alkane such as a bis(hydroxyaryl)Cm»alkane, preferably a bis(hydroxyaryl)C μalkane, bis(hydroxyphenyl)cyclohexane And other bis(hydroxyaryl)cycloalkanes [e.g. bis(hydroxyaryl)Cm cycloalkanes, preferably bis(hydroxyaryl)Cdo cycloalkanes), 4,4--bis(hydroxybenzene) a bis(hydroxyphenyl) ketone such as an ether or a bis(hydroxyphenyl) ketone such as 4,4 or bis(hydroxyphenyl) ketone, such as bisphenol S

i S -11 - .201106029 bis(hydroxyphenyl) anthraquinone, bis(hydroxyphenyl) maple, bisphenolphthalein [eg 9,9-bis(4-hydroxyphenyl)anthracene, 9,9- Bis(4-hydroxy-3-methyl)anthracene, etc.). These bisphenols may also be Cm alkylene oxide adducts. These bisphenols may be used singly or in combination of two or more. The polycarbonate resin may be a polyester carbonate resin obtained by copolymerizing a dicarboxylic acid component (aliphatic, alicyclic or aromatic dicarboxylic acid or its mercapto halide). These polycarbonate resins may be used singly or in combination of two or more. A preferred polycarbonate resin is a resin based on bis(hydroxyphenyl) C, .6 alkane, for example, a bisphenol A type polycarbonate resin. In the bisphenol A type polycarbonate resin, the ratio of the copolymerizable monomer other than bisphenol A is, for example, 20 mol% or less, preferably 10 mol% or less (for example, 0.1 to 10 m). %)about. The average molecular weight of the polycarbonate resin, for example, the viscosity measured in a dichloromethane solution having a concentration of 0-7 g/dL at 20 t can be determined to have a viscosity average molecular weight of about 10,000 to 200,000 (for example, 15,000 to 150,000). For example, 15,000 to 120,000, preferably 17,000 to 100,000, more preferably 18,000 to 50,000 (especially 18,000 to 30,000). When the molecular weight of the polycarbonate resin is smaller, the mechanical strength of the film is liable to lower. When the molecular weight is too large, the melt fluidity is lowered, and the handleability at the time of film formation or the uniform dispersibility of the dispersed phase is liable to be lowered. The melt flow rate (MFR) of the polycarbonate resin is a standard IS01 1 33 (300 ° C, 1.2 kg load (11.8 N)), and may be, for example, selected from the range of about 3 to 30 g/10 minutes, for example, 5 to 30 g. /10 points, preferably 6 to 25 g/10 minutes, -12-201106029 is preferably 7 to 20 g/10 minutes (especially 8 to 15 g/10 minutes). The viscosity of the polycarbonate resin is measured by a rotary rheometer (manufactured by Anton Paar Co., Ltd.) at a temperature of 270 ° C and a shear rate of 10 sec 1 , for example, 100 to 1,500 Pa·s, preferably 200 to 1. 200 Pa · s, more preferably 300 to lOOOPa·s (especially 500 to 750 Pa·s). The glass transition temperature of the polycarbonate resin may be selected, for example, from the range of about 110 to 250 ° C, but the stretching temperature may be set to be low, and from the viewpoint of the selection range of the resin of the expandable dispersed phase, for example, 110 It is about 180 ° C, preferably 120 to 160 ° C, more preferably about 130 to 160 ° C (especially 140 to 155 ° C). In addition, the glass transition temperature can be measured using a differential scanning calorimeter, for example, using a differential scanning calorimeter ("DSC6200" manufactured by Seiko Instruments Inc.), and measuring at a temperature rising rate of 1 (TC/min) under a nitrogen stream. The continuous phase may contain a polymer alloy of a polycarbonate resin and another resin (especially a transparent resin) in a range that does not impair the optical properties or mechanical properties of the polycarbonate resin. The resin (transparent resin, etc.) may, for example, be a transparent resin constituting a continuous phase, etc., and the ratio of the other resin is, for example, 100 parts by weight or less, preferably 50 parts by weight, based on 100 parts by weight of the polycarbonate resin. In the following, it is more preferably 1 part by weight or less (for example, 0.1 to 10 parts by weight). Specific examples of the polymer blending include, for example, a polycarbonate resin composition disclosed in JP-A-9-183892. (a resin composition in which a polyester resin and a transesterification reaction catalyst are blended in a polycarbonate to reduce haze and birefringence), as disclosed in Japanese Laid-Open Patent Publication No. Hei No. Hei. A polycarbonate resin composition (a resin composition in which an aromatic 201106029 group olefin compound or a vinyl cyanide compound is blended in a polycarbonate), and a polycarbonate resin composition disclosed in Japanese Patent No. 4021741 (a polyester and a ring) The oxygen-modified polyolefin is blended with the resin composition of the polycarbonate), etc. (Dispersed phase) The dispersed phase is immiscible with respect to the polycarbonate-based resin constituting the continuous phase, and as long as it is in-plane birefringence (in the pull) The transparent resin having a refractive index in the extending direction and an absolute value of the refractive index difference in the direction perpendicular to the stretching direction of 0.05 or more is not particularly limited. The in-plane birefringence is, for example, 0.05 to 0.5, preferably 0.1. It is more preferably about 0.15 to 0.3 (especially 0.2 to 0.25). In the present invention, a continuous phase is formed of a polycarbonate resin, and a transparent resin having a large intrinsic birefringence is used to constitute a dispersed phase, whereby a low ratio is obtained. The stretching can exhibit an effective high refractive index difference between the continuous phase and the dispersed phase, and can modulate a component having high scattering characteristics and high polarization characteristics. For such a transparent resin, for example, a cyclic olefin can be used. Resin, vinyl-containing resin (polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyvinylpyrrolidone, etc.), styrene resin (styrene-acrylonitrile resin, etc.), acrylic resin (poly (a) Acryl-based resin (poly(meth)acrylic acid alkyl ester, etc.), acrylic resin (poly(meth)acrylonitrile, etc.), polyester resin (amorphous aromatic) a polyester resin, an aliphatic polyester resin, a liquid crystal polyester, or the like, a polyamide resin (polyamide 6, polyamine 66, polyamine 610, etc.), a cellulose derivative (cellulose B) Acid esters, etc., synthetic rubbers (polybutadiene, polyisoprene, etc.), natural rubber, etc. These transparent resins can be used.

Γ S -14- 201106029 Use alone or in combination of two or more. In the transparent resin, it is preferable that the refractive index is substantially the same as that of the polycarbonate resin, and the refractive index in the stretching direction can be easily increased by stretching, and it is preferably a polyester resin. In particular, it is a polyalkylene aryl resin. The polyalkylene arylate resin is an alkylene aryl compound unit as a main component', and may contain, for example, a homo- or copolyester, which contains 50 mol% or more, preferably 75 to 100 mol%, more preferably It is a ratio of 80 to 100 mol% (especially 90 to 100 mol%). The copolymerizable monomer constituting the copolyester may contain a dicarboxylic acid component (for example, Cm aromatic such as terephthalic acid, isophthalic acid, 2,7-naphthalene dicarboxylic acid or 2,5-naphthalenedicarboxylic acid). Cm alkane dicarboxylic acid such as dicarboxylic acid, adipic acid, azelic acid or azelaic acid, 1,4-cyclohexanedicarboxylic acid or the like (: 4.12 cycloalkanedicarboxylic acid, etc.) a diol component (for example, C2.ie alkanediol such as ethylene glycol, propylene glycol, butanediol' neopentyl glycol, polyc2.4 alkylene glycol such as diethylene glycol or polyethylene glycol, a Cm cycloalkanediol such as 1,4-cyclohexanedimethanol or an aromatic diol such as bisphenol a) or a hydroxycarboxylic acid component (for example, p-hydroxybenzoic acid or p-hydroxyethoxybenzoic acid). These copolymerizable monomers may be used singly or in combination of two or more. Examples of the polyalkylene arylate resin include polyethylene terephthalate, propylene terephthalate, and poly(p-pair). Polyethylene terephthalate resin such as polybutylene terephthalate, such as polyethylene terephthalate resin, polyethylene naphthalate, polybutylene naphthalate, polybutylene naphthalate, etc. An alkyl ester resin or the like. In the present invention Among these polyalkylene aryl-based resins, a refractive index equivalent to that of the polycarbonate-based resin is obtained before stretching, and refraction can be easily performed in the stretching direction by stretching -15 to 201106029. In view of the increase in the rate, it is preferably a polyalkylene naphthalate resin (especially a polyphthalic acid C2 alkylene ester resin such as a polyethylene naphthalate resin). The alkylene ester-based resin may, for example, be a homopolyester of a naphthoic acid dialkyl ester unit (especially a naphthalene dicarboxylic acid C2.4 alkylene ester unit such as ethylene-2,6-naphthalate), or The content of the alkylene naphthalate unit is 80% by mole or more (especially 90% by mole or more) of the copolyester. The copolymerizable monomer constituting the copolyester may, for example, be a dicarboxylic acid component as described above. A diol component, a hydroxycarboxylic acid, etc. Among these copolymerizable monomers, a dicarboxylic acid component such as terephthalic acid or the like can be widely used. A polyester resin (for example, a polyalkylene naphthyl ester resin) The average molecular weight may be selected, for example, from the range of the number average molecular weight of from 5,000 to 1,000,000, for example from 10,000 to 500,000. It is preferably from 12,000 to 300,000, more preferably from about 1,500 to about 100,000. When the molecular weight of the polyethylene naphthalate resin is too large, the melt fluidity is lowered, and the aspect ratio of the dispersed phase is liable to lower. The number average molecular weight is measured by gel permeation chromatography and can be measured by conversion of polystyrene. The viscosity of the polyester resin is a rotary rheometer (manufactured by Anton Paar Co., Ltd.) at 270 ° C 'cutting speed lOsec·1 When measured under the conditions, for example, 200 to 5000 Pa·s, preferably 300 to 4000 Pa·s, more preferably 500 to 3000 Pa·s (especially 1000 to 2000 Pa·s), and the viscosity of the polycarbonate resin. The ratio, for example, the viscosity of the polycarbonate resin/viscosity of the polyester resin = 2/1 to 1/10, preferably 2/1 to 1/5, more preferably 2/1 to 1/3 (especially 1/1 to 1/2.5). Ratio of the two

i S -16 - 201106029 When the ratio is in this range, the two resins are sufficiently mixed, and a dispersion layer having a moderate size can be uniformly formed in the continuous phase, and at the same time, the dispersed phase can be controlled to a moderate particle diameter. A high in-plane birefringence is imparted to the dispersed phase. The glass transition temperature of the polyester resin (for example, polyalkylene naphthalate resin) can be selected, for example, from about 50 to 200 ° C, since the aspect ratio of the dispersed phase can be easily increased by stretching. It should be noted that the glass transition temperature of the polycarbonate resin is lower, and may be as low as, for example, 1 to 100 ° C, preferably 5 to 80 ° C, more preferably 10 to 50 ° C (especially It is around 20 to 40 °C). Specifically, the glass transition temperature of the polyester resin is, for example, 60 to 180 ° C, preferably 80 to 150 ° C, more preferably 90 to 130 ° C (especially 100 to 120 ° C). In addition, the glass transition temperature can be measured using a differential scanning calorimeter. For example, a differential scanning calorimeter ("DSC6200" manufactured by Seiko Instruments Inc.) is used, and the temperature is raised at a rate of 1 (TC/min) under a nitrogen stream. The average diameter of the longitudinal direction of the dispersed phase is from 0.8 to 10 #m, preferably from 1 to 5 #m, more preferably from about 1.5 to 3 μπι. The average diameter of the dispersed phase in the minor axis direction is from 0.05 to 0.8/zm. Preferably, it is from 0.1 to 0.7 gm, more preferably from about 0.2 to 0.6 μm, and the average aspect ratio of the dispersed phase is from 2 to 1,000 (e.g., from 2 to 200), preferably from 3 to 500, more preferably from 5 to 100 (especially 7 to 30). The dispersed phase is separated from the continuous phase by stretching, and becomes a different shape from the spherical shape. The different shape may be, for example, a football shape (a ellipsoid such as a spheroid). Flat body, rectangular parallelepiped shape, fibrous or filamentous body, etc.

E S -17- 201106029 The average diameter of the pre-dispersed phase can be, for example, about 0.3-3 μ m. The higher the alignment coefficient of the particle constituting the dispersed phase, the higher the better, for example, 0.34 or more (about 0.44 to 1), preferably 0.4 to 1 (for example, 0.5 to 1)', more preferably 0.7 to 1 (especially It is about 0.8 to 1). The higher the alignment coefficient of the dispersed phase particles, the higher the polarization characteristics. Further, the alignment coefficient can be calculated according to the following formula. The alignment coefficient = (3 < cos2 0 > · 1) / 2 [wherein, 0 represents the angle between the long axis of the granular dispersed phase and the X axis of the film (in the case where the long axis is parallel to the X axis, 0 = 〇'), <C〇s20> represents the average of cos2 0 calculated for each dispersed phase particle, which is represented by the following formula. <cos20>=S n(0)· cos2 θ · d θ (wherein η(0) represents a ratio (% by weight) of the dispersed phase particles having an angle of 0 in the fully dispersed phase particles). The ratio (weight ratio) of the continuous phase (the resin component constituting the continuous phase) to the dispersed phase (the resin component constituting the dispersed phase) is selected depending on the type of the resin, the melt viscosity, the light diffusibility, and the like, and may be selected, for example, from the continuous phase/ The dispersed phase is from 99/1 to 50/50, preferably from 98/2 to 70/30, more preferably from about 96/4 to 80/20, and usually from about 95/5 to about 85/15. When such a ratio is used, it is not necessary to compound the two components in advance, and even if the particles of the respective components are directly melt-kneaded, the dispersed phase can be uniformly dispersed and subjected to alignment treatment such as one-axis stretching. A good polarizing element can be obtained by preventing the occurrence of voids. (additive)

-18-.201106029 In the polarizing element of the present invention, the dispersed phase does not form a substantial void at the interface with the continuous phase, and can be bonded or adhered to the continuous phase, and a compatibilizing agent can be blended as needed. In the case of a compatibilizing agent, the dispersed phase may be combined or adhered to the continuous phase via the remelting agent. In the case of a remelting agent, a polymer (random, block or graft copolymer) having the same or a common composition as the resin constituting the continuous phase and the dispersed phase can be generally used, and the continuous phase and the dispersed phase are formed. The resin having affinity (random, block or graft copolymer), etc., specifically, a polyester elastomer, a remelting agent having an epoxy group in the main chain, especially an epoxy Modified aromatic ethylene-diene block copolymers [eg epoxidized styrene-butadiene-styrene (SBS) block copolymers or epoxidized styrene-butadiene block copolymers (SB) epoxidized styrene-diene copolymer or epoxy-modified styrene-diene copolymer]. The epoxidized aromatic ethylene-diene copolymer has high transparency and a softening temperature of about 70 ° C. In various combinations of the continuous phase and the dispersed phase, the resin is mutually melted, and the dispersed phase can be uniformly dispersed. dispersion. The ratio of the remelting agent, for example, as a ratio (weight ratio) to the dispersed phase, is a dispersed phase/interstabilizing agent (weight ratio) = 99/1 to 50/50, preferably 99/1 to 7 0/30, More preferably, it is about 98/2~80/20. Further, the ratio of the remelting agent is, for example, from 1 to 20 parts by weight, preferably from 0.5 to 15 parts by weight, more preferably from 1 to 1% by weight, based on 100 parts by total of the continuous phase and the dispersed phase. About. The polarizing element of the present invention may also contain a stabilizer such as a conventional additive such as an antioxidant, a heat stabilizer, a plasticizer, an antistatic agent, etc., within a range that does not impair the optical properties [S3 -19-201106029 Fuel, sputum, UV absorber, etc. (Characteristics of the polarizing element) The refractive index difference between the continuous phase and the dispersed phase of the linearly polarized light of the present invention is large in the stretching direction of the sheet (hereinafter referred to as "X-axis direction"), and is relative to The vertical direction of the stretching direction (hereinafter referred to as "Y-axis direction") is small. Therefore, the polarizing element has a scattering characteristic in the direction in which the refractive index difference is large, and a part of the polarized light is scattered before the stretched sheet, and the residual polarized light is scattered after the stretched sheet, and most of the light is not absorbed. Further, the polarized light having a small refractive index difference has a property of being substantially transmitted. That is, the polarizing element scatters a large amount of linearly polarized light in the stretching direction, and the linearly polarized light in the direction perpendicular to the stretching direction reduces scattering or substantially no scattering in the stretching direction. With respect to the refractive index difference, the absolute enthalpy of the refractive index difference between the continuous phase and the dispersed phase in the X-axis direction is 0.1 or more (for example, 0.1 to 0.5), preferably 0.1 to 0.3, more preferably 0.1 to Ό.2, The absolute value of the refractive index difference between the continuous phase and the dispersed phase in the Y-axis direction is 0.1 or less, for example, 0.05 or less, preferably 0_04 or less, more preferably 0.03 or less (for example, 0.001 to 〇.〇3 or so). When the absolute 値 of the difference in refractive index is within this range, the backscattering (the balance between reflection and transmission scattering is excellent, and excellent polarization characteristics and scattering characteristics can be exhibited, and the brightness of the display device can also be improved. In the case of a poorly polarized element, in the continuous phase and the dispersed phase, the anisotropy of the respective refractive indices is small and the refractive indices are substantially the same as each other in the stage of the film (so-called cast sheet) which is preferably used for film formation in -20-201106029. For example, the absolute enthalpy of the difference in refractive index between the polyphenyl carbonate-based resin before stretching and the transparent resin constituting the dispersed phase is 0.05 or less, preferably 0.04 or less, more preferably 〇.〇3 or less. When the refractive index difference of the resin is within this range, the anisotropy of the refractive index difference can be easily exhibited by stretching. In general, it is known that when the cast sheet is subjected to one-axis stretching, the stretching direction of the continuous phase is performed. The refractive index (in the X-axis direction) is remarkably increased. In the above-mentioned Patent Documents 2 to 5, the refractive index in the z-axis direction of the transparent resin of the continuous phase does not change much, and the refractive index in the X-axis direction of the transparent resin of the continuous phase is made. In contrast, the polarizing element of the present invention has a small refractive index change even in the X-axis direction of the continuous phase of the polarizing element of the present invention, and the dispersed phase of the particulate phase has a refractive index in the X-axis direction and the x-axis direction. Significantly, that is, the continuous phase does not cause a large refractive index difference due to stretching, whereas the dispersed phase is deformed into a football-like shape or a rod-shaped shape by stretching, and a large refractive index difference is generated. Therefore, the polarizing element of the present invention is stretched by one axis, so that the refractive indices of the continuous phase and the dispersed citrus are substantially different in the X-axis direction, and substantially coincident in the x-axis direction. Thus, a polarizing element having a polarizing element can be produced. The polarized light having substantially the same refractive index is substantially transmitted, and the polarized light having a different refractive index is a scattering characteristic. Further, in the present invention, the dispersed phase is different from the conventional polarizing element, and the dispersed phase has the X-axis direction and the x-axis direction. Large refractive index difference, but similar to the conventional [S ] -21-201106029 polarizing element, exhibits scattering characteristics for polarized light, and the larger the refractive index difference between the continuous phase and the dispersed phase in the X-axis direction, The scattering property of the polarized light in this direction is increased, and the ratio of the backscattering (reflected light) is also increased. On the other hand, the polarizing light in the γ-axis direction is the same as the refractive index of the continuous phase and the refractive index of the dispersed phase. The polarized light is transmitted as a completely transparent body without scattering. In the present invention, the refractive index difference in the Y-axis direction can be selected depending on the application, and a transparent resin having a refractive index difference before stretching in the above range is used. When the refractive indices of the two phases are substantially the same, the transmission scattering property in the Y-axis direction can be improved. On the other hand, the diffusion effect can be reduced by making the refractive index of the two phases different. The polarizing element of the present invention has this. The refractive index difference is high, so the total light transmittance in the Y-axis direction is high, for example, 80% or more (for example, 80 to 99%), preferably 82 to 98%, more preferably about 85 to 95%. The diffused light transmittance in the Y-axis direction is, for example, 30% or more (for example, 30 to 90%), preferably 40 to 80%, more preferably 50 to 70%, in the case of using as a diffusion sheet, without being used. In the case of a diffusion sheet, it may be, for example, 30% or less, preferably 20 % or less, more preferably 10% or less. On the other hand, the polarizing element of the present invention is excellent in scattering characteristics in the X-axis direction, and has a total light transmittance of 75% or less (for example, 丨〇 to 75%) in the X-axis direction, preferably 70% or less (for example, 20 to 70). More preferably, it is 60% or less (25 to 60%). That is, the polarizing element of the present invention has a high reflectance (backscattering ratio) and a reflectance (backscattering ratio) in the stretching direction of 25% or more. (for example 25 to 90%), preferably 30% or more (for example, 30 to 80%), more preferably 40% or more rs -22 to 201106029 (for example, 40 to 75%), especially 50% or more (for example, 50 to 70%). In other words, the polarizing element of the present invention has a total light transmittance of 80% or more in the Y-axis direction and a reflectance (reflectance due to a specular reflection component and a backscattering component) in the X-axis direction of 30% or more. It imparts light diffusion and polarization to the transmitted light, so it has properties similar to those of the absorption type polarizing plate. Further, since it is reflected without being absorbed by the polarized light, there is no temperature rise due to the absorption of the single polarized light which is a disadvantage of the absorption type, and it becomes a good scattering type polarizing plate similar to the transmissive polarizing plate. Further, since the reflected light contributes to the improvement of the luminance, the polarizing element of the present invention can be used as a brightness enhancement sheet for a liquid crystal display device or the like. In addition, the total light transmittance and the diffused light transmittance are as described in Examples to be described later, and a polarizing measuring device (haze meter) (NDH-300A, manufactured by Nippon Denshoku Industries Co., Ltd.) is used, and regarding total light, It can be measured according to the method of JIS K7361-1, and the haze (diffused light) can be measured according to the method of JIS K 7136. The polarizing element of the present invention has a thickness of 3 to 500 / zm, preferably 5 to 400 / Zm (for example, 30 to 400 μm) is more preferably from 5 to 300; am (for example, from 50 to 300 μm). The polarizing element of the present invention may be a single layer film, or a laminated film of a transparent resin layer which does not impair optical properties may be laminated on the at least one side (especially on both sides). When the polarizing element is protected by the transparent resin layer, the detachment or adhesion of the dispersed phase particles can be prevented, and the anion brasion or manufacturing stability of the polarizing element can be improved, and the strength or handleability can be improved. The resin of the transparent resin layer may be selected from the examples as the continuous phase or the dispersed phase.

ί S -23- 201106029 The composition of the resin. A preferred transparent resin layer can be formed from a polycarbonate resin which is continuously the same system (especially the same). The transparent resin layer may contain the above-mentioned conventional additives insofar as the optical properties are not impaired. The total thickness of the transparent resin layer may be, for example, the same as that of the polarizing element. In particular, in the case where the thickness of the polarizing element layer is about 3 to 500 / / m, the thickness of the transparent resin layer may be selected from 3 to 150 / / m, preferably 5 to 50 / zm, more preferably 5 to 15 / zm. about. The ratio of the thickness of the polarizing element to the total thickness of the transparent resin layer may be, for example, selected from the range of the polarizing element/transparent resin layer = 5/95 to 99/1, and is usually 50/50 to 99/1, preferably 70. /30 to 95/5 or so. The thickness of the laminated film is, for example, 6 to 800 μm, preferably 10 to 600 μm, more preferably 20 to 450 /Z m or so. On the surface of the polarizing element, a release agent such as polyoxygenated oil may be applied in a range that does not impede optical characteristics, or a corona discharge treatment may be performed. Further, on the surface of the polarizing element, the uneven portion of the film may be formed. When such a concavo-convex portion is formed, anti-glare property can be imparted. [Manufacturing Method of Polarizing Element] The polarizing element is obtained by dispersing a transparent resin constituting a dispersed phase in a polycarbonate resin constituting a continuous phase. For example, an additive such as a polycarbonate resin, a transparent resin, and an optional remelting agent may be blended, melt-mixed, or the like by a conventional method (for example, melt blending, tumbler method, etc.), if necessary. The film is formed by extrusion from a T die or a ring die with an annular hole, whereby the dispersed phase is dispersed in the continuous phase.

L S -24- 201106029 The melting temperature is preferably not less than the melting point of the polycarbonate resin and the transparent resin, and varies depending on the type of the resin, but is, for example, about 150 to 290 ° C, preferably about 200 to 260 ° C. Next, the alignment treatment of the dispersed phase is preferably, for example, (1) a method of stretching the extruded sheet, and (2) a surface-drawing the extruded sheet to form a film to cure the sheet. It can be carried out by a method such as stretching. In order to exhibit the excellent characteristics of the polarizing element of the present invention, it is necessary to form a film of the resinous resin in a continuous phase of the polycarbonate resin by solidifying and cooling the sheet in which the dispersed phase of the transparent resin is dispersed. The sheet is formed to reheat the cast sheet, and thereafter it is preferably subjected to alignment processing by stretching. Stretching can be a simple free-width-axial stretching, or a wide (fixed width) one-axis stretching. The one-axis stretching method is not particularly limited, and for example, a method of drawing both ends of the cured film (pulled and stretched), and preparing a pair of rolls facing each other (twin-roll) A plurality of series (for example, 2 series) are arranged in parallel to insert the film into the respective twin rolls while stretching the film between the double rolls on the feeding side and the double rolls on the delivering side. , the feeding speed of the film of the double roll on the delivery side is made faster than that of the double roll on the feeding side, thereby stretching (the stretching between the rolls), inserting the film between the pair of rolls facing each other, Rolling film rolling method (rolling rolling); fixed width and one-axis stretching by a stretcher method. In the one-axis stretching, drawing and drawing, in particular, a viewpoint of producing a true deformation in the dispersed phase and increasing the in-plane birefringence of the dispersed phase

For I S -25- 201106029, free-width one-axis stretching can be used as appropriate. Further, a fixed-width one-axis stretching by a stretcher method can also be suitably used. The fixed width and one-axis stretching caused by the stretcher method is reduced in the direction of stretching accompanying the stretching, and the width in the vertical direction is reduced, and is not the same as the free-width one-axis stretching having an uneven thickness of the full width. The method in which the width of the stretching direction does not change in the vertical direction is extremely advantageous in order to maintain the anisotropy of the dispersed phase while producing a sheet having a uniform width. Furthermore, although the details of the action are unknown, changes in the refractive index of the dispersed phase are also effective. The axial stretching caused by the stretcher method allows the stretching direction to be the flow direction of the sheet or the width direction of the sheet. When the flow direction is increased, the production speed is increased, and in order to obtain a desired wide polarizing element, it is necessary to enlarge the width of the cast sheet. On the other hand, when it is in the width direction, since it is stretched in the transverse direction, even if the width of the cast sheet is reduced, a desired wide polarizing element can be obtained, but the production speed is lowered. These methods can be selected according to the purpose. In the one-axis stretching by the stretcher mode, the stretching speed is selected from the range of, for example, about 50 to 1,000 mm/min, for example, from 1 to 800 mm/min, preferably 150, in accordance with the stretching temperature or magnification. It is about 700 mm / min, more preferably about 200 to 600 mm / min (especially 400 to 600 mm / min). The stretching temperature is preferably a temperature higher than the glass transition temperature of the polycarbonate resin, and when the glass transition temperature of the polycarbonate resin is Tg, for example, Tg to (Tg + 80) ° C, preferably (Tg + 5) ) to (Tg + 50) ° C, more preferably (Tg + 5) to (Tg + 30) ° C [especially (Tg + 8) to (Tg + 20) ° C] high temperature. The specific stretching temperature may be, for example, 120 to 180 ° C, preferably 150 to 175 ° C, and more preferably about S1 -26 to 201106029 of 150 to 170 ° C (especially 160 to 170 ° C). The stretching ratio may be selected from a wide range, but in the present invention, even at a relatively low stretching ratio, the refractive index in the stretching direction and the refractive index perpendicular to the stretching direction may cause a large difference. For example, it may be 1.2 to 5 times (for example, 1.5 to 4 times), preferably 2 to 4 times, more preferably 2.5 to 3.8 times (especially 2.5 to 3.5 times). In particular, in the present invention, even if the stretching ratio is 4 times or less, since a sheet having excellent scattering characteristics can be produced, it is possible to easily use a stretching apparatus such as a single stretching which is caused by the above-described stretcher method. Manufacturing. Since the polarizing element of the present invention exhibits polarizing characteristics by relaxing the birefringence of the continuous phase, the stretched heat-treatment is performed at a temperature higher than the stretching temperature or the stretching temperature (the sheet is maintained as it is) Heat treatment under the length) maintains the polarization characteristics while imparting heat resistance. The heat treatment temperature may be selected, for example, from a stretching temperature to a temperature higher than the stretching temperature by a temperature of about 50 ° C. For example, the temperature may be from a stretching temperature to a temperature higher than the stretching temperature by about 30 ° C, for example, The heat treatment time is substantially the same as the stretching temperature, for example, 0.1 to 30 minutes, preferably 1 to 10 minutes, more preferably 2 to 5 minutes, and may be selected depending on the temperature, for example, at a temperature of about 165 ° C. The situation can be about 2 to 3 minutes. By this heat treatment, the refractive index difference of the continuous phase can be reduced, and since the refractive index of the continuous phase and the dispersed phase can be made uniform in the direction perpendicular to the stretching direction, the optical characteristics can be improved. Further, heat resistance or strength such as dimensional stability of the polarizing element can be improved.

-27- 201106029 In addition, the laminated film can be obtained by a conventional method such as a co-extrusion molding method, a bonding method (extrusion bonding method, dry bonding method, etc.), and a transparent resin layer is laminated on at least one side of the polarizing element layer. . [Face light source device and transmissive liquid crystal display device] The surface light source device of the present invention includes a tubular light source (such as a fluorescent tube), and a light guiding member that emits light from the tubular light source from a side surface for emitting from a flat emitting surface. a polarizing element disposed on a light emitting side of the light guiding member. Further, in the surface light source device, a polarizing element can be used as a scattering type element. Fig. 1 is a schematic cross-sectional view showing an example of a transmissive liquid crystal display device using a surface light source device for improving luminance by using the polarizing element of the present invention. The liquid crystal display device 1 includes a fluorescent tube 2 as a tubular light source, and is disposed at a side portion of the fluorescent tube 2, and receives light from the fluorescent tube 2 from a side surface for emitting light from a flat emitting surface. a member (light guide plate) 4; a TN-type liquid crystal cell 7 illuminated by the light emitted from the light guide plate 4; a reflective member (reflector) 3 for reflecting the incident light; and the light guide plate 4 and the light guide plate 4 a polarizing element 5 between the liquid crystal cells 7; and a diffusion sheet 6 that diffuses light transmitted through the polarizing element 5. In the liquid crystal display device 1, light from the fluorescent tube 2 is reflected by the reflecting plate 3 through the light guiding plate 4, and is emitted from the light guiding plate 4. The emitted light is transmitted through the polarizing element 5, the polarized light having a small difference in refractive index between the continuous phase and the dispersed phase (Y-axis direction) is substantially transmitted, and the polarized light having a large refractive index difference (X-axis direction) is scattered and transmitted. Or reflection. The reflected light is again reflected by the reflector 3 through the light guide plate 4. Next, -28-201106029, by this reflection, a portion of the light that is rotated by 90 degrees in the direction of a direction occurs. The polarized light is guided by the rotating light, and is again passed through the light guide plate 4 to the polarizing element 5 and transmitted. The light which is directed by the polarized light is again reflected by the polarizing element 5, but is reflected by the reflecting plate 3, and the polarized light is again guided by the polarizing element 5 by being rotated by 90 degrees. The light passing through the polarizing element 5 is scattered by the diffusion sheet 6 and illuminates the liquid crystal cell 7. Therefore, most of the light from the fluorescent tube 2 is aligned with most of the polarization axes and emitted from the polarizing element 5, so if the liquid crystal cell 7 is incident on the polarization axis of the absorption type polarizing plate (not shown) on the side, When the axis coincides with this axis, it is possible to more efficiently utilize the light of the fluorescent tube 2 which has been used for only about 50%. The polarizing element of the present invention used for this purpose is preferably used in a transmissive liquid crystal display device having a total light transmittance of linear polarized light in the Y-axis direction of 80% or more and linear polarized light in the X-axis direction ( The reflectance of the regular reflection component and the backscatter component is 30% or more. The brightness enhancement effect of the polarizing element of the present invention is extremely effective even if it is laminated on a commonly used light guide plate/diffuser/sheet. Further, the brightness improving effect of the polarizing element of the present invention is similarly applied to a direct type backlight (surface light source device) which does not use a light guide plate, and a transmissive liquid crystal display device using the same. [Reflective liquid crystal display device] The reflective liquid crystal display device of the present invention is provided with a liquid crystal cell between the polarizing element and the reflecting plate of the present invention, and may be disposed between the liquid crystal cell and the reflecting plate. The polarizing element of the invention. In these devices, it is preferred to be in the liquid

L S -29- 201106029 A reflective liquid crystal display device in which the polarizing element is disposed between the crystal cell and the reflecting plate. Fig. 2 is a schematic cross-sectional view showing an example of a reflective liquid crystal display device in which brightness is improved by using the polarizing element of the present invention. The reflective liquid crystal display device 10 includes a reflecting member (reflecting plate) 13 for reflecting external light, and a TN type liquid crystal cell 17 for reflecting light emitted from the reflecting plate 13 (for a reflective liquid crystal device); The external light is introduced into the liquid crystal cell 17 for the absorption type polarizing plate 18; the polarizing element 15 is disposed between the reflecting plate 13 and the liquid crystal cell 17 to scatter the emitted light from the reflecting plate 13. In the reflection type liquid crystal display device 10, the external light incident on the absorption type polarizing plate 18 passes through only the light of the polarizing plate and the polarization axis, and reaches the liquid crystal cell 17. The light incident on the liquid crystal cell 17 rotates the polarization direction and reaches the polarizing element 15. In the case where the display of the liquid crystal cell is a dark display, the polarizing element 15 is disposed such that the polarization direction of the external light passing through the liquid crystal cell 17 coincides with the Y-axis direction of the polarizing element 15. By the polarized light of the absorptive polarizing plate 18, the polarizing element 15 passes through the polarizing element 15 again, and the polarized light is guided to rotate in the liquid crystal cell 17, and becomes a direction perpendicular to the polarizing axis of the absorptive polarizing plate 18, so that it is darkly displayed. On the other hand, in the case where the display of the liquid crystal cell is made to be bright display, the polarizing element 15 is disposed such that the polarization direction of the external light passing through the liquid crystal cell 17 coincides with the X-axis direction of the polarizing element 15. In the external light incident on the absorbing polarizing plate 18, only the polarizing plate 18 is aligned with the polarizing axis

The light of L S -30-201106029 passes through the liquid crystal cell 27, and the liquid crystal cell 17 does not rotate in the polarization direction, but reaches the polarizing element 15. The polarized light incident on the polarizing element 15 is scattered in the reflection direction or the transmission direction. The light scattered in the transmission direction is reflected by the reflection plate 13, and immediately merges with the light scattered by the polarizing element 15 to reach the absorption type polarizing plate 18, and is transmitted as it is. Since the transmitted light is sufficiently scattered by the polarizing element 15, a good white display with less viewing angle dependence is displayed. Fig. 3 is a schematic cross-sectional view showing another example of a reflective liquid crystal display device in which brightness is improved by using the polarizing element of the present invention. The reflective liquid crystal display device 20 includes a liquid crystal cell 27 for a reflective liquid crystal device illuminated by the emitted light from the reflecting plate 23, a reflecting member (reflecting plate) 23 for reflecting external light, and a liquid crystal cell 27; A quarter-wavelength plate 29 between the reflection plate 23 and a polarizing element 25 disposed between the 1⁄4 wavelength plate 29 and the liquid crystal cell 27 for scattering the emitted light from the reflection plate 23. Further, the liquid crystal cell 27 is a liquid crystal containing a dichroic dye type. In the reflective liquid crystal display device 20, in the state in which the liquid crystal cell 27 is not applied, the liquid crystal molecules are aligned in the alignment processing direction of the liquid crystal (the direction parallel to the glass substrate of the liquid crystal cell), and the two-color property is similarly applied. Pigment alignment. The external light incident on the liquid crystal cell 27 is a linearly polarized component which is parallel to the long axis direction of the dichroic dye molecules and can be absorbed by the dichroic dye. Further, a linearly polarized component having a vertical direction with respect to the long axis direction of the dichroic dye molecules enters the polarizing element 25 through the liquid crystal cell 27. When the polarizing element 25 is disposed such that the guiding of the linearly polarized light passing therethrough coincides with the Y-axis direction of the polarizing element 8, the polarizing light-31-201106029 that emits the polarizing element 25 is a quarter-wavelength plate (phase difference plate) 29 Rounded polarized light. Further, the reflection plate 23 is reflected by the reflection plate 23, and the circular polarization guide is rotated, and the wave plate 29 is again placed, and the original linear polarization guide is rotated by 90 degrees to re-polarize the element 25. The incident light becomes the X-axis light of the polarizing element 25, and is scattered as a line parallel to the long-axis direction of the molecules of the dichroic dye, and the liquid crystal cell 27 is absorbed by the dichroic dye in the liquid crystal cell 27. The 7K display is good black. On the other hand, in the state where the liquid crystal cell 27 is applied, the liquid crystal is vertically aligned with the glass substrate and also faces the dichroic dye. The incident external light is not absorbed by the liquid crystal unit 27 pigment containing the dichroic dye, but passes through the liquid crystal cell 27 and is incident on the light incident from the polarizer. In the polarizing element 25, the polarization in the Y-axis direction is However, the polarized light in the X-axis direction is scattered. Then, the polarized light that emits the polarized light is circularly polarized on the quarter-wavelength plate 29, and the light reflected by the reflecting plate 23 is reversely rotated in the opposite direction of the circularly polarized light, and is incident on the quarter-wavelength plate 29 again. The polarized light in the incident > axis direction passes through the polarized light which is circularly polarized and is scattered by the polarizing element 25 by 90 。. Therefore, since the light containing the dichroic dye unit cell 27 is reflected light which is totally scattered, it can be displayed in white. When the polarizing element of the present invention is used, it is possible to impart high scattering properties to transmitted light and reflected light, so that the liquid crystal display screen can be improved, and in particular, even a large liquid crystal display surface can be circularly polarized throughout the entire image. /4 is incident on the polarized light, so the molecules are equally matched with 2 colors; It is reflected by element 25 as usual. In revolve fc, Y ί rotates, and the liquid crystal is good and polarized. bright

[S J -32- 201106029 Display. Therefore, the transmissive or reflective liquid crystal display device can be widely used for display portions of electronic products such as personal computers, word processors, liquid crystal televisions, mobile phones, watches, and electronic computers. In particular, a liquid crystal display device in a portable information device can be suitably used. EXAMPLES The present invention is described in more detail below on the basis of examples, but the invention is not limited to the examples. Further, the characteristics of the polarizing elements obtained in the examples and the comparative examples can be evaluated in accordance with the following methods. [Sectional view of the sheet] The pre-processed sheet and the stretched sheet before stretching are cut into small pieces in two directions (in the direction of the stretched sheet, parallel and perpendicular to the stretching direction). When observed by a transmission electron microscope (manufactured by JEOL Ltd.; TEM1200EXII), the polymer in the dispersed phase forms an ellipsoidal (or elongated linear) scater (granular shape) arranged in the extrusion direction. The dispersed phase was measured and the average of the long-axis length and the short-axis length of 50 dispersed phase particles was measured. [Refractive Index] The refractive index of the continuous and dispersed phases is the stretching direction (X-axis direction) and the vertical direction (Y-axis direction) when the respective resin monomer sheets are stretched under the same conditions as in the examples and the comparative examples. The measurement was performed at a wavelength of 633 nm using a prism weighing instrument (manufactured by Metricon Co., Ltd.). Further, the refractive index difference was obtained from the measured refractive index. [Evaluation of Polarization and Scattering Characteristics] A polarizing measuring device (manufactured by Nippon Denshoku Industries Co., Ltd.,

-33-201106029 NDH-30 0A), the total light is measured by the method of JIS K7361-1, and the haze (diffused light) is measured by the method of JIS K7136. In the measurement, the absorption-type polarizing plate was inserted into the light source side, and the light source was linearly polarized only in the vertical direction, and the polarizing elements of the examples and the comparative examples were inserted, and the total light transmittance and diffusion of the polarized light with respect to the polarizing element were measured. Light rate, total light reflectance (calculated as total light reflectance = 1 - total light transmittance). The total light reflectance is consistent with the reflectance (reflectance of the specular reflection component and the backscatter component). The measurement system is such that the difference in the refractive index difference between the continuous phase and the dispersed phase is the same as the polarization axis of the absorbing polarizing plate ("parallel" in Table 3) and the refractive index difference between the continuous phase and the dispersed phase is The direction of the large direction is measured in accordance with the polarization axis of the absorptive polarizing plate ("vertical" in Table 3). [Evaluation of brightness improvement degree] Using a polarizing measuring device (Nippon Denshoku Industries Co., Ltd., NDH-3 00 A), a reflecting plate and an absorbing polarizing plate were inserted into the light source side, and the total light transmittance was measured. As a benchmark. The polarizing element of the examples and the comparative examples were inserted between the reflecting plate and the absorptive polarizing plate so that the direction in which the refractive index difference between the continuous phase and the dispersed phase was small was consistent with the direction of transmission of the absorptive polarizing plate. Transmittance. With respect to the previous reference 値, the 値 which normalizes the measurement 値 is used as the brightness improvement degree as described below. (Brightness improvement degree) = [(Measurement 値) / (reference 値)] χ 100. [trouser tearing] The tear strength is carried out by a trouser tear method in accordance with the method of JIS K7128-1. Under constant temperature conditions (23 °C, relative humidity 50%), the test piece was cut to a preset size of -34-201106029, and a 75 mm slit was placed in the stretching direction to tear at a speed of 200 mm/min. Crack test. The 20 mm of the beginning of the tear and the 5 mm before the completion of the tear were excluded, and the average enthalpy of the 50 mm tear strength from the residual was obtained. The test was performed at N = 5 to obtain an average 値. Example 1 Polyethylene naphthalate resin (PEN, manufactured by Teijin Kasei Co., Ltd.) "Teonex" as a resin constituting a dispersed phase was used using a two-axis extruder (manufactured by Chiba Iron Works Co., Ltd., PCM3 0) TN8065S"' viscosity at 270 °C and shear rate lOsec·1: 1578 Pa·s) 10 parts by weight, bisphenol A type polycarbonate resin as a resin constituting a continuous phase (PC, manufactured by Mitsubishi Engineering Plastics Co., Ltd.) , "Medium viscosity product IupilonS-2 000", viscosity average molecular weight 1 8000 to 20000, MFR10g/10 minutes, 270 ° C and shear rate lOsec · 1 medium viscosity: 681 Pa · s) 90 parts by weight, at cylinder temperature 280 The mixture was melted, kneaded, and cooled to prepare pellets. The pellet obtained was compacted by a compact press (Toyo Seiki Seisakusho Co., Ltd., mini test press 10) at 270 ° C and a press pressure of 10 MPa for 3 minutes to prepare a pressed sheet having a thickness of 1 mm. The obtained sheet was cut into a width of 40 mm and a length of 70 mm, and a tensile tester (TENSILON UCT-5T, manufactured by Orientec Co., Ltd.) equipped with a thermostatic unit was used, and preheated at 165 ° C with a chuck between 50 mm. After 5 minutes, the film was stretched to 3.5 times at a stretching speed of 500 mm/min, and then, after being held in a chuck, at 165 ° for 3 minutes (after heat treatment, it was quenched to room temperature to obtain a stretched sheet. Example 2 - 35 - 201106029 A stretched sheet was produced in the same manner as in Example 1 except that a pressed sheet having a thickness of 50 μm was produced by press forming. Example 3 A press having a thickness of 500 Mm was produced by press forming. A sheet was stretched to 5 times, and the stretched sheet was produced in the same manner as in Example 1. Example 4 A pressed sheet having a thickness of 500 //m was produced by press molding, and the obtained sheet was pulled. The stretched sheet was produced in the same manner as in Example 1 except that it was stretched to 3 times. Example 5 A pressed sheet having a thickness of 300 / im was produced by press molding, and the obtained sheet was stretched to 2 times, and the others were Same as in the first embodiment, manufacturing pull Sheet 6. Example 6 A pressed sheet having a thickness of 300 #m was produced by press molding in the same manner as in Example 1. The obtained sheet was cut into a width of 40 mm and a length of 70 mm, and a tensile tester equipped with a constant temperature unit was used, with a chuck between the trays of 50 mm. After preheating at 155 ° C for 5 minutes, the film was stretched to 2 times at a stretching speed of 200 mm/min, and then heat-treated at 155 ° C for 3 minutes while being held in a chuck. At room temperature, a stretched sheet was obtained. Example 7 5 parts by weight of a polyethylene naphthalene-36-201106029 acid ethylene glycol resin as a resin constituting a dispersed phase was used as a resin constituting a continuous phase using a biaxial extruder. 95 parts by weight of a bisphenol A type polycarbonate resin, melt-kneaded at a cylinder temperature of 280 ° C, and extruded and cooled to prepare granules. The obtained granules were pressed at 270 ° C and 10 MPa using a small press. After pressing for 3 minutes, a pressed sheet having a thickness of 300 00 //m was produced. The obtained sheet was cut to a width of 40 mm and a length of 70 mm, and a tensile tester equipped with a constant temperature unit was used, and the chuck was 50 mm at 155 ° C. After preheating for 5 minutes, stretch at a stretching speed of 200 mm / min. After being doubled, the film was heat-treated at 155 ° C for 3 minutes while being held in a chuck, and then quenched to room temperature to obtain a stretched sheet. Example 8 The same procedure as in Example 1 was carried out to obtain a thickness of 300 by press molding. /zm pressed sheet. The obtained sheet was cut into a width of 40 mm and a length of 70 mm, and was stretched by using a tensile tester equipped with a thermostatic unit at a temperature of 50 mm between the chucks and at a temperature of 15 ° C for 5 minutes. After stretching at a speed of 200 mm/min to 2 times, it was quenched to room temperature to obtain a stretched sheet. Comparative Example 1 8 parts by weight of a polystyrene resin (PS, manufactured by Toyo Styrol Co., Ltd., "GPMW4D"), which is a resin constituting a dispersed phase, as a resin constituting a continuous phase, using a two-axis extruder 92 parts by weight of ethylene formate resin was melt-kneaded at a cylinder temperature of 280 ° C, pressed and cooled to prepare pellets. The obtained pellets were press-molded at a pressing pressure of 270 ° C and 10 MPa for 3 minutes using a small press to prepare a pressed sheet having a thickness of 550 # m. The obtained sheet was cut into a width of 40 mm and a length of 70 mm, and a tensile tester having a constant temperature unit of -37-.201106029 was used, and 50 mm between the chucks was used, and after preheating at 133 ° C for 5 minutes, the tensile speed was 100 mm/min. After stretching to 4 times, it was quenched to room temperature to obtain a stretched sheet. Comparative Example 2 A stretched sheet was produced in the same manner as in Comparative Example 1, except that the pressed sheet was stretched to 5 times. Comparative Example 3 A stretched sheet was produced in the same manner as in Comparative Example 1, except that the pressed sheet was stretched to 6 times. Comparative Example 4 In the same manner as in Comparative Example 1, the obtained pressed sheet was cut into a width of 40 mm and a length of 70 mm, and a tensile tester equipped with a thermostatic unit was used, and 50 mm between the chucks was used, and preheated at 133 ° C for 5 minutes, and then pulled. After stretching at a stretching speed of 100 mm/min to 5 times, the film was heat-treated at 133 ° C for 3 minutes while being held in a chuck, and then quenched to room temperature to obtain a stretched sheet. Comparative Example 5 4 parts by weight of a polystyrene resin as a resin constituting a dispersed phase was used as a 96-fold portion of a polyethylene naphthalate resin constituting a continuous phase using a biaxial extruder at a cylinder temperature of 280. The mixture was melt-kneaded at ° C, and extruded and cooled to prepare pellets. The obtained pellets were press-formed at a pressing pressure of 270 °G and 10 MPa for 3 minutes using a small press to prepare a pressed sheet having a thickness of 1 mm. The obtained sheet was cut into a width of 40 mm and a length of 70 mm, and a tensile tester equipped with a constant temperature unit was used, and the temperature between the chucks was 50 mm, and after preheating at 133 ° C for -38-.201106029 5 minutes, the tensile speed was 〇 After 〇mm/min was stretched to 6 times, it was quenched to room temperature to obtain a stretched sheet. Comparative Example 6 12 parts by weight of a polystyrene resin as a resin constituting a dispersed phase, and 88 parts by weight of a polyethylene naphthalate resin as a resin constituting a continuous phase were used as a cylinder temperature of 280 using a biaxial extruder. The mixture was melted, kneaded, and cooled to prepare pellets. The obtained pellets were press-formed at a pressing pressure of 270 ° C and 10 MPa for 3 minutes using a small press to prepare pressed sheets having a thickness of 1 mm. The obtained sheet was cut into a width of 40 mm and a length of 70 mm, and was stretched to a stretch rate of 100 mm/min by a tensile tester equipped with a thermostatic unit at a distance of 50 mm between the chucks at 133 ° C for 5 minutes. After the doubling, it was quenched to room temperature to obtain a stretched sheet. The mixing composition, stretching temperature and magnification in Examples 1 - 8 and Comparative Examples 1 to 6 'The heat treatment temperature and the thickness of the stretched sheet are shown in Table 1. Further, the average diameter and refractive index of the dispersed phase in the pre-processed sheet and the stretched sheet were measured, and the results are shown in Table 2. Further, the results of the total light transmittance, the reflectance, the diffused light transmittance, the brightness improvement degree, and the pants tear of the stretched sheet are shown in Table 3.

IS -39- '201106029 [Table 1] Continuous phase (parts) Dispersed phase (parts) Stretching temperature (°C) Stretching ratio heat treatment (°C) Thickness ("m) Example 1 PC: 90 PEN: 10 165 3.5 165 280 Example 2 PC: 90 PEN: 10 165 3.5 165 142 Example 3 PC: 90 PEN: 10 165 5 165 120 Example 4 PC: 90 PEN: 10 165 3 165 140 Example 5 PC: 90 PEN : 10 165 2 165 152 Example 6 PC: 90 PEN: 10 155 2 155 145 Example 7 PC: 95 PEN: 5 155 2 155 144 Example 8 PC: 90 PEN: 10 155 2 No 145 Comparative Example 1 PEN: 92 PS: 8 133 4 No 145 Comparative Example 2 PEN: 92 PS: 8 133 5 No 127 Comparative Example 3 PEN: 92 PS: 8 133 6 Μ y\\\ 107 Comparative Example 4 PEN: 92 PS: 8 133 5 133 130 Comparative Example 5 PEN: 96 PS: 4 133 6 Μ 153 Comparative Example 6 PEN: 88 PS: 12 133 6 No 159

-40- 201106029 Interphase refractive index difference 0.008 0.008 0.005 0.020 0.084 0.030 0.030 0.033 1 ;0.003 1 0.002 0.003 0.004 0.003 0.003 X-axis 0.218 0.218 | 0.215 0.190 0.142 0.162 0.162 0.139 0.216 0.227 0.233 0.222 0.233 0.233 Continuous phase refractive index 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.032 1 i 0.203 1_ 0.211 0.215 0.208 0.215 0.215 Y-axis 1.590 1.590 1.590 1.590 1.590 1.590 1.590 1.577 1 | 1.588 1.590 1.591 1.593 1.591 1.591 SX 1.590 1.590 1.590 1.590 1.590 1.590 1.590 1.609 1.791 1.801 1.806 1.801 1_ 1.806 1.806 Disperse phase refraction Rate _1 〇t 1 0.210 0.210 0.170 0.058 0.132 0.132 0.138 0.016 0.018 0.021 0.010 0.021 0.021 1.598 1.598 1.595 1.610 1.674 1.620 1.620 1.610 1 1.591 1.592 1.594 1.589 1.594 1.594 X-axis 1.808 1.808 1.805 1.780 1.732 1.752 1.752 1.748 1.575 1.574 1.573 1.579 1.573 1.573 Stretching dispersion diameter (μηι) Y-axis to wo in VO νς κο· MD VO 〇r-; 1 v〇1 vq X-axis 00 1 < 00 1 1 cn Csi fi cn ii cn tH cn i 1 cn r-i Ό oi 1 VO 1 cn \D Dispersion diameter before machining (^m) Y-axis Oo o OO o' oo 〇oo OO OO OO OO o < T—^ 1 1 pr—H 1 <r—< X-axis oo oo OO oo oo oo oo o oo o H «—4 1 < 1 p < • 4 Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 8 Comparison Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 • 201106029 [ Table 3] - Parallel Vertical Brightness Lifting Pants Tear (N/mm) Full Transmittance (%) Total Light Reflectance (%) Full Transmittance (%) Diffusion Transmittance (%) Example 1 35 65 87 58 124 3.95 Example 2 48 52 92 67 123 3.88 Example 3 49 51 86 75 119 3.26 Example 4 59 41 94 48 114 4.25 Example 5 -_72 28 91 76 99 7.32 Example 6 58 42 87 68 109 7.25 Example 7 62 38 89 51 104 7.62 Example 8 69 31 90 68 100 7.28 Comparative Example 1 57 43 86 73 109 1.92 Comparative Example 2 54 46 87 72 112 0.85 Comparative Example 3 50 50 87 65 118 0.29 Comparative Example 4 51 49 87 63 115 0.83 Comparative Example 5 46 54 89 37 121 0.32 Comparative Example 6 L 50 50 89 70 120 0.28 S Table shows that the polarizing element of the example can improve the brightness and the tear strength. Example 1 which is 2 and the polarizing element, although the draw ratio was 3.5 times' have shown high luminance and increase the degree of scattering characteristic. On the other hand, in the polarizing element of the comparative example, although the tear strength is low and the stretching ratio is high, the improvement in brightness and the scattering characteristics are not sufficient. Further, in the polarizing element of the comparative example (especially Comparative Examples 3, 5 and 6), voids were observed.

ί S -42- .201106029 The occurrence of whitening. INDUSTRIAL APPLICABILITY The polarizing element of the present invention can be utilized in various surface light source devices, and in particular, can be effectively used for a transmissive or reflective liquid crystal display device (for example, a personal computer, a word processor, a liquid crystal television, a mobile phone, a timepiece) , display parts of electronic products such as electronic computers, etc.). BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a schematic cross-sectional view showing an example of a transmissive liquid crystal display device using the surface light source device of the present invention. Fig. 2 is a schematic cross-sectional view showing an example of a reflection type liquid crystal display device of the present invention. Fig. 3 is a schematic cross-sectional view showing another example of the reflective liquid crystal display device of the present invention. [Main component symbol description] 1,10,20 Display liquid crystal display device 2 Fluorescent tube 3, 13, 23 Reflecting member or reflective layer 4 Light guide plate 5, 15, 25 Polarizing element 6 Diffusion sheet ^17, 27 Liquid crystal cell 18 Absorptive polarizer 29 1/4 wavelength plate -43-

Claims (1)

201106029 VII. Patent application scope: 1. A polarizing element comprising a polarizing element for dispersing a dispersed phase containing a transparent resin in a granular form in a stretched sheet comprising a continuous phase of a polycarbonate resin, the continuous phase The in-plane birefringence is less than 0.05, the in-plane birefringence of the dispersed phase is 0.05 or more, and the refractive index difference between the continuous phase and the dispersed phase with respect to the linear polarization, in the stretching direction and the perpendicular direction with respect to the stretching direction different. 2. The polarizing element according to claim 1, wherein the absolute value of the refractive index difference between the continuous phase and the dispersed phase in the stretching direction is 0.1 to 0.3, and the continuous phase in the vertical direction with respect to the stretching direction is The absolute enthalpy of the refractive index difference of the dispersed phase is 0.1 or less. 3. For the polarizing element of claim 1 or 2, wherein the average length of the major axis and the minor axis of the dispersed phase are 0.8 to ΙΟ/zm and 0.05 to 0.8 // m, respectively, and the average aspect ratio of the dispersed phase is 2. To 200. 4. The polarizing element according to any one of claims 1 to 3, wherein the total light transmittance of the linearly polarized light in the vertical direction with respect to the stretching direction is 80% or more 'and parallel to the direction of the stretching direction. The reflectance of linear polarized light is more than 30%. 5. The polarizing element according to any one of claims 1 to 4, wherein the polycarbonate resin is a glass transition temperature of 120 to 16 (TC bisphenol A type polycarbonate resin. 6. Patent application) The polarizing element according to any one of items 1 to 5, wherein the dispersed phase comprises a polyester resin. 7. The polarizing element according to any one of claims 1 to 6, wherein the dispersed phase is #-44- 201106029 A polyalkylene naphthalate-based resin is provided. 8. The polarizing element of any one of claims 1 to 7 wherein the ratio of the continuous phase to the dispersed phase is continuous phase/dispersion phase = 99/1 M 50 /50 (weight ratio) 9. The method for producing a polarizing element according to the first aspect of the invention is characterized in that a sheet formed by melt-mixing a polycarbonate resin and a transparent resin is subjected to axial stretching. The method of the ninth aspect of the invention, wherein the glass transition temperature of the polycarbonate resin is Tg, and is axially stretched by 1.2 to 4 times at a temperature of from Tg ° C to (Tg + 80) ° C. For example, the method of claim 9 or 10 further increases the stretching temperature The temperature is heat-treated. 12. A light source device comprising the polarizing element according to any one of claims 1 to 8. 13. A liquid crystal display device comprising the items 1 to 8 as claimed in the patent application. A polarizing element of any of the following. -45-