JP2009157343A - Polarizing plate and liquid crystal display using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polarizing plate that facilitates defect inspection having high accuracy, even when an oriented polyethylene terephthalate film is used as a protective film, and to provide a liquid crystal display device that uses the polarizing plate, suppressing color unevenness, when observed in an oblique direction and having superior visibility. <P>SOLUTION: The polarizing plate comprises a polarizing film, made of a polyvinylalcohol system resin and an oriented polyethylene terephthalate film layered with an adhesive layer on one side of the polarizing film, in which the shift angle of the orientation primary axis of the oriented polyethylene terephthalate film with respect to the orienting axis is not larger than 15°, and the MOR value (maximum orientated ratio), measured by a microwave transmission type molecular orientation meter is not smaller than 1.5. The liquid crystal display device uses this polarizing plate. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a polarizing plate in which a stretched polyethylene terephthalate film is laminated on one side of a polarizing film made of a polyvinyl alcohol resin via an adhesive layer, and a liquid crystal display device using the polarizing plate.

  A polarizing plate is usually a protective film (for example, cellulose acetate represented by triacetyl cellulose) through an adhesive layer on one side or both sides of a polarizing film made of a polyvinyl alcohol-based resin to which a dichroic dye is adsorbed and oriented. System protective film). A polarizing plate having such a laminated structure is bonded to a liquid crystal cell with an adhesive via another optical film as necessary, and is used as a component of a liquid crystal display device.

  Applications of liquid crystal display devices are rapidly expanding as thin display devices such as liquid crystal televisions, liquid crystal monitors, and personal computers. In particular, the market for liquid crystal televisions is remarkably expanding, and the demand for cost reduction is very high. A polarizing plate for a liquid crystal television is usually formed by laminating a triacetyl cellulose film (TAC film) with a water-based adhesive on both sides of a polarizing film made of a polyvinyl alcohol resin to which a dichroic dye is adsorbed and oriented. A retardation film is laminated on the outer surface of one side of the plate via an adhesive.

  As the retardation film laminated on the polarizing plate, a stretched product of a polycarbonate-based resin film or a stretched product of a cycloolefin-based resin film is used. Retardation films composed of very few cycloolefin resin films are frequently used. The laminated product of such a polarizing plate and a retardation film made of a cycloolefin resin film reduces the number of components or simplifies the manufacturing process in order to improve productivity and reduce product cost. For example, JP-A-8-43812 (Patent Document 1) discloses a laminated structure of a cycloolefin-based (norbornene-based) resin film / polarizing film / TAC film having a retardation function. Yes.

JP-A-2005-70140 (Patent Document 2), JP-A-2005-181817 (Patent Document 3) and JP-A-2005-208456 (Patent Document 4) describe polarized light made of a polyvinyl alcohol resin. It is described that a film and a cycloolefin-based protective film are bonded with a urethane-based aqueous adhesive.
JP-A-8-43812 JP-A-2005-70140 JP 2005-181817 A JP-A-2005-208456

  In the use of large-screen liquid crystal televisions, the needs for wall-mounted televisions are becoming thinner, and in this case, the following points are problems as components used for liquid crystal panels.

(1) It is necessary to reinforce the strength of the panel in response to the thin and large screen of the liquid crystal panel.
(2) It is necessary to reduce the thickness of members used in response to the reduction in the thickness of liquid crystal televisions.

  (3) The gap between the liquid crystal panel and the backlight system on the back surface is narrowed, and it is necessary to prevent circular unevenness and Newton's ring caused by contact between the liquid crystal panel and the backlight system.

  In order to solve the above problems, it is conceivable to use a stretched polyethylene terephthalate film which is excellent in mechanical strength and cost of the film as a protective film for the polarizing plate. However, when a stretched polyethylene terephthalate film is used as a protective film, color unevenness (also referred to as interference unevenness or rainbow unevenness) is conspicuous when placed on a liquid crystal display device and viewing an image, resulting in poor visibility. .

  Furthermore, since the stretched polyethylene terephthalate film generally causes optical anisotropy due to the bowing phenomenon during production, when used as a protective film for a polarizing plate, the two polarizing films are perpendicular to each other in the orientation main axis. When a stretched polyethylene terephthalate film is sandwiched between polarizing films during visual inspection using the crossed Nicols method to detect foreign objects and defects, this optical anisotropy becomes a hindrance, making it easy to overlook defects and increase the screen size. There is a possibility that the defective rate of the polarizing plate accompanying the increase.

  Due to the above bowing phenomenon, the stretched polyethylene terephthalate film is a stretched film in which the orientation main axis is parallel to the stretch axis is only a slight region in the center of the film, and the orientation main axis and the stretch axis do not substantially deviate. It is very difficult to make.

  The present invention has been made in order to solve the above-mentioned problems, and the purpose thereof is a polarizing plate capable of accurately performing defect inspection even when a stretched polyethylene terephthalate film is used as a protective film, Another object of the present invention is to provide a liquid crystal display device using the same, in which color unevenness when observed from an oblique direction is suppressed, and the visibility is excellent.

  As a result of intensive studies to solve such problems, the present inventors laminated a stretched polyethylene terephthalate film having specific properties on one side of a polarizing film made of a polyvinyl alcohol resin via an adhesive layer. It has been found that by using a polarizing plate, a polarizing plate having high mechanical strength and excellent visibility can be obtained even if it is thin, and the present invention has been completed. That is, the present invention is as follows.

  The polarizing plate of the present invention comprises a polarizing film made of a polyvinyl alcohol-based resin and a stretched polyethylene terephthalate film laminated on one side of the polarizing film via an adhesive layer, and the stretching axis of the orientation main axis of the stretched polyethylene terephthalate film And a MOR value measured by a microwave transmission type molecular orientation meter is 1.5 or more.

  The polarizing plate of the present invention preferably further has a protective film or an optical compensation film laminated on the side opposite to the side on which the stretched polyethylene terephthalate film of the polarizing film is laminated.

  In the polarizing plate of the present invention, the stretched polyethylene terephthalate film laminated on the polarizing film can have an antiglare layer on the outer surface.

  The polarizing plate of the present invention preferably further has a pressure-sensitive adhesive layer on the outer surface of the polarizing film opposite to the side on which the stretched polyethylene terephthalate film is laminated.

  The present invention also provides a liquid crystal display device including a liquid crystal panel in which a polarizing plate having the above-mentioned pressure-sensitive adhesive layer is bonded to a liquid crystal cell via the pressure-sensitive adhesive layer.

  The polarizing plate of the present invention enables inspection by the crossed Nicol method, and the liquid crystal display device using such a polarizing plate of the present invention also suppresses color unevenness caused by the retardation of the stretched polyethylene terephthalate film, It can be suitably applied to a liquid crystal display device for a large screen liquid crystal television.

  Specifically, the polarizing film used in the polarizing plate of the present invention is obtained by adsorbing and orienting a dichroic dye on a uniaxially stretched polyvinyl alcohol resin film. The polyvinyl alcohol-based resin can be obtained by saponifying a polyvinyl acetate-based resin. As the polyvinyl acetate resin, in addition to polyvinyl acetate which is a homopolymer of vinyl acetate, copolymers of vinyl acetate and other monomers copolymerizable therewith, such as ethylene-vinyl acetate copolymer, etc. Is mentioned. Examples of other monomers copolymerizable with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and acrylamides having an ammonium group.

  The saponification degree of the polyvinyl alcohol resin is usually 85 to 100 mol%, preferably 98 mol% or more. These polyvinyl alcohol resins may be modified. For example, polyvinyl formal, polyvinyl acetal, polyvinyl butyral and the like modified with aldehydes may be used. Moreover, the polymerization degree of polyvinyl alcohol-type resin is in the range of 1000-10000 normally, Preferably it exists in the range of 1500-5000.

  A film obtained by forming such a polyvinyl alcohol resin is used as a raw film of a polarizing film. The method for forming the polyvinyl alcohol-based resin is not particularly limited, and can be formed by a conventionally known appropriate method. Although the film thickness of the raw film which consists of polyvinyl alcohol-type resin is not specifically limited, For example, it is about 10-150 micrometers.

  The polarizing film is usually a process of dyeing a polyvinyl alcohol resin film with a dichroic dye to adsorb the dichroic dye (dyeing process), and a polyvinyl alcohol resin film adsorbed with the dichroic dye is boric acid. It is manufactured through a step of treating with an aqueous solution (boric acid treatment step) and a step of washing with water after the treatment with the boric acid aqueous solution (water washing treatment step).

  In the production of the polarizing film, the polyvinyl alcohol-based resin film is usually uniaxially stretched, but this uniaxial stretching may be performed before the dyeing treatment step or during the dyeing treatment step, It may be performed after the dyeing process. When uniaxial stretching is performed after the dyeing treatment step, the uniaxial stretching may be performed before the boric acid treatment step or during the boric acid treatment step. Of course, uniaxial stretching can be performed in these plural stages. Uniaxial stretching may be performed uniaxially between rolls having different peripheral speeds, or may be performed uniaxially using a hot roll. Moreover, the dry-type extending | stretching which extends | stretches in air | atmosphere may be sufficient, and the wet extending | stretching which extends | stretches in the state swollen with the solvent may be sufficient. The draw ratio is usually about 3 to 8 times.

  Dyeing of the polyvinyl alcohol resin film with the dichroic dye in the dyeing process is performed, for example, by immersing the polyvinyl alcohol resin film in an aqueous solution containing the dichroic dye. As the dichroic dye, for example, iodine, a dichroic dye or the like is used. Examples of dichroic dyes include C.I. I. Dichroic direct dyes composed of disazo compounds such as DIRECT RED 39 and dichroic direct dyes composed of compounds such as trisazo and tetrakisazo are included. In addition, it is preferable that the polyvinyl alcohol-type resin film performs the immersion process to water before a dyeing process.

  When iodine is used as the dichroic dye, a method of dyeing a polyvinyl alcohol resin film by dipping it in an aqueous solution usually containing iodine and potassium iodide is employed. The content of iodine in this aqueous solution is usually 0.01 to 1 part by weight per 100 parts by weight of water, and the content of potassium iodide is usually 0.5 to 20 parts by weight per 100 parts by weight of water. When iodine is used as the dichroic dye, the temperature of the aqueous solution used for dyeing is usually 20 to 40 ° C., and the immersion time (dyeing time) in this aqueous solution is usually 20 to 1800 seconds.

On the other hand, when a dichroic dye is used as the dichroic dye, a method of immersing and dyeing a polyvinyl alcohol-based resin film in an aqueous solution containing a water-soluble dichroic dye is usually employed. The content of the dichroic dye in this aqueous solution, usually, 1 × 10 ^-4 to 10 parts by weight per 100 parts by weight of water, preferably 1 × 10 ^-3 to 1 parts by weight, particularly preferably 1 × 10 ^{- 3} to 1 × 10 ⁻² parts by weight. This aqueous solution may contain an inorganic salt such as sodium sulfate as a dyeing assistant. When a dichroic dye is used as the dichroic dye, the temperature of the dye aqueous solution used for dyeing is usually 20 to 80 ° C., and the immersion time (dyeing time) in this aqueous solution is usually 10 to 1800 seconds. is there.

  The boric acid treatment step is performed by immersing a polyvinyl alcohol-based resin film dyed with a dichroic dye in a boric acid-containing aqueous solution. The amount of boric acid in the boric acid-containing aqueous solution is usually 2 to 15 parts by weight, preferably 5 to 12 parts by weight per 100 parts by weight of water. When iodine is used as the dichroic dye in the dyeing process described above, the boric acid-containing aqueous solution used in this boric acid treatment process preferably contains potassium iodide. In this case, the amount of potassium iodide in the boric acid-containing aqueous solution is usually 0.1 to 15 parts by weight, preferably 5 to 12 parts by weight per 100 parts by weight of water. The immersion time in the boric acid-containing aqueous solution is usually 60 to 1200 seconds, preferably 150 to 600 seconds, and more preferably 200 to 400 seconds. The temperature of the boric acid-containing aqueous solution is usually 50 ° C. or higher, preferably 50 to 85 ° C., more preferably 60 to 80 ° C.

  In the subsequent washing process, the polyvinyl alcohol-based resin film after the boric acid treatment described above is washed with water, for example, by immersing it in water. The water temperature in the water washing treatment is usually 5 to 40 ° C., and the immersion time is usually 1 to 120 seconds. After the water washing treatment, a drying treatment is usually performed to obtain a polarizing film. The drying process is preferably performed using, for example, a hot air dryer or a far infrared heater. The temperature of the drying treatment is usually 30 to 100 ° C, preferably 50 to 80 ° C. The time for the drying treatment is usually 60 to 600 seconds, preferably 120 to 600 seconds.

  In this way, the polyvinyl alcohol resin film is uniaxially stretched, dyed with a dichroic dye, treated with boric acid and washed with water to obtain a polarizing film. The thickness of this polarizing film is usually in the range of 5 to 40 μm. The polarizing plate of the present invention has a structure in which a stretched polyethylene terephthalate film having specific physical properties is laminated on one side of such a polarizing film via an adhesive layer.

  The stretched polyethylene terephthalate film used in the present invention is at least one or more uniaxially stretched films formed by melt-extrusion of at least one polyethylene terephthalate resin, followed by longitudinal stretching and, if necessary, lateral stretching, or two It is an axially stretched film.

  The polyethylene terephthalate resin means a resin in which 80 mol% or more of repeating units are composed of ethylene terephthalate, and may contain other dicarboxylic acid components and diol components. Representative examples of other dicarboxylic acid components include isophthalic acid, p-β-oxyethoxybenzoic acid, 4,4′-dicarboxydiphenyl, 4,4′-dicarboxybenzophenone, bis (4-carboxyphenyl) ethane. , Adipic acid, sebacic acid, 5-sodium sulfoisophthalic acid, 1,4-dicarboxycyclohexane and the like, but are not limited thereto. Typical examples of other diol components include propylene glycol, butanediol, neopentyl glycol, diethylene glycol, cyclohexanediol, ethylene oxide adduct of bisphenol A, polyethylene glycol, polypropylene glycol, polytetramethylene glycol, etc. It is not limited to. These dicarboxylic acid components and diol components can be used in combination of two or more if necessary. Moreover, oxycarboxylic acids, such as p-oxybenzoic acid, can also be used together. Further, as other copolymerization component, a dicarboxylic acid component containing a small amount of an amide bond, a urethane bond, an ether bond, a carbonate bond, or the like, or a diol component may be used.

  As a method for producing a polyethylene terephthalate-based resin, terephthalic acid and ethylene glycol (and other dicarboxylic acid or other diol as required) may be directly polycondensed, dialkyl ester of terephthalic acid, and ethylene glycol (and A method of transesterification with a dialkyl ester of another dicarboxylic acid or another diol if necessary, followed by polycondensation, and an ethylene glycol ester of terephthalic acid (and other dicarboxylic acid if necessary) ( In addition, a method of polycondensation of other diol esters) as required can be arbitrarily used.

  The stretched polyethylene terephthalate film used in the present invention can be produced by forming the raw material resin as described above into a film shape and subjecting it to a stretching treatment. The method for producing the stretched polyethylene terephthalate film is arbitrary and is not particularly limited. However, the non-oriented film obtained by melting the raw material resin and extrusion-molded into a sheet shape is higher than the glass transition temperature of polyethylene terephthalate. A method of performing heat setting after mechanical stretching at temperature can be mentioned.

  Although the temperature at the time of extending | stretching will not be restrict | limited especially if it is the temperature more than the glass transition temperature of a polyethylene terephthalate, it is preferable to exist in the range of 80-160 degreeC.

  The stretch ratio of the stretched polyethylene terephthalate film in the present invention is preferably 1.1 to 6 times, more preferably 2 to 5.5 times in the longitudinal direction and the width direction of the film. This is because when the draw ratio is less than 1.1 times, the mechanical strength of the stretched polyethylene terephthalate film tends to be insufficient. Moreover, the draw ratio exceeding 6 times is not realistic in manufacturing technology.

  In addition, from the viewpoint of reducing distortion of the orientation main axis in the stretched polyethylene terephthalate film (displacement relative to the stretch axis), the film is subjected to the longitudinal direction (the running direction of the film) after the stretching and before the heat setting treatment, It is preferable to perform relaxation treatment in the width direction of the film (direction perpendicular to the running direction of the film). The temperature for the relaxation treatment is 90 to 250 ° C, preferably 120 to 200 ° C. Although the relaxation amount varies depending on the transverse stretching conditions, it is preferable to set the relaxation amount and the temperature so that the heat-shrinkage rate at 150 ° C. of the stretched polyethylene terephthalate film after the relaxation treatment is 2% or less.

  The temperature of the heat setting treatment is usually 180 to 250 ° C, preferably 200 to 245 ° C. In the heat setting treatment, first, after performing the heat setting treatment at a constant length, the distortion of the orientation main axis is reduced, and in order to improve the strength such as heat resistance, further in the film longitudinal direction (film running direction) or film width direction It is preferable to perform a relaxation treatment. The amount of relaxation in this case is preferably adjusted such that the heat-shrinkage rate at 150 ° C. of the stretched polyethylene terephthalate film after the relaxation treatment is 1 to 10%, more preferably 2 to 5%.

  The stretched polyethylene terephthalate film used in the present invention has a misalignment angle with respect to the stretching direction of the orientation main axis (maximum strain of the orientation main axis) of 15 degrees or less (preferably 12 degrees or less, more preferably 10 degrees or less). One of the features. If the maximum value of the strain of the orientation main axis is greater than 15 degrees, when a stretched polyethylene terephthalate film is sandwiched between polarizing films during visual inspection using the crossed Nicols method, it becomes an obstacle to inspection, and it is easy to miss foreign matters and defects. In addition, a sufficient color unevenness suppressing effect cannot be obtained when it is bonded to the screen of a liquid crystal display device. The maximum value of the orientation main axis strain of the stretched polyethylene terephthalate film described above is, for example, a retardation film inspection apparatus RETS system (manufactured by Otsuka Electronics Co., Ltd.), a microwave transmission type molecular orientation meter (MOA) (Oji Scientific Instruments ( It is possible to measure by using the product).

  The thickness of the stretched polyethylene terephthalate film used in the present invention is preferably in the range of 15 to 75 μm, and more preferably in the range of 20 to 60 μm. When the thickness of the stretched polyethylene terephthalate film is less than 15 μm, it tends to be difficult to handle (inferior in handleability), and when the thickness exceeds 75 μm, the orientation main axes at both ends of the film due to the bowing phenomenon during film formation Therefore, the yield is increased, the film thickness is increased, and the cost is increased. Further, the merit of thinning tends to be reduced, which is not preferable.

  The stretched polyethylene terephthalate film used in the present invention has a MOR (Maximum Oriented Ratio) value of 1.5 or more (preferably 2.0 or more, more preferably 2.2 or more, and even more preferably 3.0 or more). It is also one of the features. This is because when a polarizing plate using a stretched polyethylene terephthalate film having an MOR value of less than 1.5 is applied to a liquid crystal display device, the oblique interference unevenness tends to increase. The upper limit of the MOR value of the stretched polyethylene terephthalate film is not particularly limited, but 7 or less is sufficient. Here, the MOR value is a ratio (maximum value / minimum value) between the maximum value and the minimum value of the transmission microwave intensity measured by a transmission type molecular orientation meter, and serves as an anisotropy index. The MOR value can be measured using a microwave transmission type molecular orientation meter (manufactured by Oji Scientific Instruments).

  You may make the stretched polyethylene terephthalate film used for this invention contain a well-known additive as needed. Known additives include, for example, lubricants, antiblocking agents, heat stabilizers, antioxidants, antistatic agents, light resistance agents, impact resistance improvers and the like. However, since transparency is required in optical applications, it is preferable to keep the amount of additives added to a minimum, and the resulting stretched polyethylene terephthalate film preferably has a haze of less than 6%.

  When the stretched polyethylene terephthalate film used in the present invention is used on the viewing side of the polarizing plate, it is preferable that antiglare property (haze) is imparted. The method for imparting antiglare properties is not particularly limited. For example, according to the method for forming a film by mixing inorganic fine particles or organic fine particles in the raw material resin, the method for producing the multilayer film described above. , A method of forming a stretched film from an unstretched film having a layer mixed with inorganic fine particles or organic fine particles on one side, or mixing inorganic fine particles or organic fine particles with a curable resin binder on one side of a stretched polyethylene terephthalate film. And a method of curing the resin binder.

  The inorganic fine particles for imparting antiglare properties are not particularly limited. For example, silica, colloidal silica, alumina, alumina sol, aluminosilicate, alumina-silica composite oxide, kaolin, talc, mica, calcium carbonate , And calcium phosphate. Examples of the organic fine particles include, but are not limited to, crosslinked polyacrylic acid particles, methyl methacrylate / styrene copolymer resin particles, crosslinked polystyrene particles, crosslinked polymethyl methacrylate particles, silicone resin particles, and polyimide. Particles and the like.

  It is preferable that the haze value of the stretched polyethylene terephthalate film provided with the antiglare property thus obtained is in the range of 6 to 45%. When the haze value of the antiglare protective film is less than 6%, a sufficient antiglare effect may not appear. On the other hand, if it exceeds 45%, the screen of the liquid crystal display device using this film may be tinted and the image quality may be deteriorated.

  On the antiglare layer, functional layers such as a conductive layer, a hard coat layer, and a low reflection layer can be laminated. In addition, in the formation of the antiglare layer by the coating liquid coating, a binder resin composition having these functions can be selected.

  In the stretched polyethylene terephthalate film used in the present invention, as long as the effects of the present invention are not hindered, a functional layer having necessary characteristics according to required characteristics other than the antiglare layer and the like is laminated on one side or both sides. Can do.

  Examples of the functional layer to be laminated include a smoothing coating layer, an easy-sliding coating layer, an easy-release coating layer, an anti-blocking coating layer, and an easy-adhesion coating layer. Especially, since this extending | stretching polyethylene terephthalate film is laminated | stacked through a polarizing film and an adhesive bond layer, it is preferable that the easily bonding coating layer is laminated | stacked.

  The component constituting the easy-adhesion coating layer is not particularly limited. For example, a polyester resin, a urethane resin, or an acrylic resin having a polar group in the skeleton and a relatively low molecular weight and low glass transition temperature. Examples thereof include resins. Moreover, a crosslinking agent, an organic or inorganic filler, a surfactant, a lubricant and the like can be contained as necessary.

  The method of forming the above-mentioned coating layer on the stretched polyethylene terephthalate film is not particularly limited. For example, a method of coating the film after all stretching steps, a polyethylene terephthalate resin is stretched. Examples thereof include a method of coating during the process, that is, between the longitudinal stretching and the lateral stretching steps, and a method of coating immediately before or after being bonded to the polarizing film. Among these, from the viewpoint of productivity, a method of coating the polyethylene terephthalate resin after longitudinal stretching is preferable.

  In the polarizing plate of the present invention, a protective film or an optical compensation film may be laminated on the side of the polarizing film opposite to the side on which the stretched polyethylene terephthalate film is laminated. Examples of the protective film or the optical compensation film include transparent films such as a cellulose resin film such as a triacetyl cellulose film (TAC film), an olefin resin film, an acrylic resin film, and a polyester resin film. Moreover, you may make it laminate | stack the optical functional film mentioned later on such a transparent film.

The cellulose-based resin film is a film of a cellulose part or a completely esterified product, and examples thereof include a film made of cellulose acetate ester, propionate ester, butyrate ester, mixed ester thereof and the like. More specifically, a triacetyl cellulose film, a diacetyl cellulose film, a cellulose acetate propionate film, a cellulose acetate butyrate film, and the like can be given.
As such a cellulose ester film, appropriate commercial products such as Fujitac TD80 (Fuji Film Co., Ltd.), Fujitac TD80UF (Fuji Film Co., Ltd.), Fujitac TD80UZ (Fuji Film Co., Ltd.), KC8UX2M (Manufactured by Konica Minolta Opto), KC8UY (manufactured by Konica Minolta Opto), and the like.

  Moreover, as an optical compensation film comprising a cellulose resin film, for example, a film in which a compound having a retardation adjusting function is contained in a cellulose film, a film in which a compound having a retardation adjusting function is applied to the surface of the cellulose film, a cellulose film Examples thereof include a film obtained by uniaxially stretching or biaxially stretching a film. Moreover, in the polarizing plate of this invention, the cellulose acetate type-resin film provided with the phase difference characteristic is also used suitably, As a commercial item of the cellulose acetate type-resin film provided with this phase difference characteristic, WV BZ 438 ( Fuji Film Co., Ltd.), WV EA (Fuji Film Co., Ltd.), KC4FR-1 (Konica Minolta Opto Co., Ltd.), KC4HR-1 (Konica Minolta Opto Co., Ltd.) and the like.

  Alternatively, the cycloolefin resin film may be uniaxially stretched or biaxially stretched to form an optical compensation film. The cycloolefin resin film is a film made of a thermoplastic resin having a monomer unit made of a cyclic olefin (cycloolefin) such as norbornene or a polycyclic norbornene monomer. The cycloolefin-based film may be a hydrogenated product of a ring-opening polymer using a single cycloolefin or a ring-opening copolymer using two or more kinds of cycloolefins. It may also be an addition copolymer with an aromatic compound having a vinyl group. Further, those having a polar group introduced into the main chain or side chain are also effective.

  When using a copolymer of a cycloolefin and a chain olefin and / or an aromatic compound having a vinyl group, examples of the chain olefin include ethylene and propylene. As the aromatic compound having a vinyl group, Examples include styrene, α-methylstyrene, and nuclear alkyl-substituted styrene. In such a copolymer, the monomer unit composed of cycloolefin may be 50 mol% or less (preferably 15 to 50 mol%). In particular, when a terpolymer of a cycloolefin, a chain olefin, and an aromatic compound having a vinyl group is used, the amount of the monomer unit composed of the cycloolefin can be made relatively small as described above. In such a terpolymer, the monomer unit composed of a chain olefin is usually 5 to 80 mol%, and the monomer unit composed of an aromatic compound having a vinyl group is usually 5 to 80 mol%.

  Cycloolefin-based resins may be commercial products such as Topas (manufactured by Ticona), Arton (manufactured by JSR Corporation), ZEONOR (manufactured by Nippon Zeon Co., Ltd.), ZEONEX (manufactured by Nippon Zeon Corporation). ) And Apel (Mitsui Chemicals) can be preferably used. When such a cycloolefin-based resin is formed into a film, a known method such as a solvent casting method or a melt extrusion method is appropriately used. In addition, for example, Essina (manufactured by Sekisui Chemical Co., Ltd.), SCA40 (manufactured by Sekisui Chemical Co., Ltd.), Zeonoa Film (manufactured by Optes Co., Ltd.), Arton Film (manufactured by JSR Co., Ltd.), etc. A commercially available cycloolefin resin film may be used as the transparent protective film.

The cycloolefin-based resin film as the optical compensation film is desirably stretched in at least one direction. Thereby, an appropriate optical compensation function is provided, which can contribute to the expansion of the viewing angle of the liquid crystal display device. The in-plane retardation value R ₀ of the stretched cycloolefin-based resin film is preferably 40 to 100 nm, and more preferably 40 to 80 nm. When the in-plane retardation value R ₀ is less than 40 nm or exceeds 100 nm, the viewing angle compensation ability for the liquid crystal panel tends to be lowered. The thickness direction retardation R _th for the stretched cycloolefin resin film is preferably 80 to 300 nm, more preferably 100 to 250 nm. When the thickness direction retardation value _Rth is less than 80 nm or exceeds 300 nm, the viewing angle compensation ability for the panel tends to be reduced as described above. The in-plane retardation value R ₀ and the thickness direction retardation value R _th of the stretched cycloolefin-based resin film are represented by the following formulas (1) and (2), respectively, for example, KOBRA 21ADH (Oji Scientific Instruments ( It is possible to measure using

_{R 0 = (n x -n y} ) × d (1)
R _th = [( _nx + _ny ) / 2- _nz ] × d (2)
(The above formula (1), (in 2), n _x is stretched in-plane slow axis direction of the refractive index of the cycloolefin resin film, n _y in-plane fast axis direction (in-plane slow axis direction refractive index in the orthogonal direction to) a, the n _z refractive index in the thickness direction of the cycloolefin-based resin film stretched, d is the thickness of the cycloolefin resin film stretched.)
The preferable refractive index characteristics as described above include various adjustments such as preheating temperature during stretching, stretching temperature, heat setting (film strain reduction treatment after stretching) temperature, cooling temperature, etc. in addition to appropriately adjusting the stretching ratio and stretching speed. It can be applied by appropriately selecting the temperature (including the temperature pattern). By performing stretching under relatively loose conditions, the above preferable refractive index characteristics can be obtained. For example, the stretching ratio is preferably 1.05 to 1.6, and more preferably 1.1 to More preferably, it is 1.5 times. In the case of biaxial stretching, the stretching ratio in the maximum stretching direction may be in the above range.

  If the stretched cycloolefin-based resin film is too thick, the processability becomes inferior, and problems such as a decrease in transparency and an increase in the weight of the polarizing plate tend to occur. Therefore, the thickness of the stretched cycloolefin-based resin film is preferably in the range of 20 to 80 μm.

  As described above, the polarizing plate of the present invention has a stretched polyethylene terephthalate film laminated on one side of the polarizing film via an adhesive layer, and if necessary, a side of the polarizing film on which the stretched polyethylene terephthalate film is laminated. A protective film or an optical compensation film is laminated on the opposite surface. From the viewpoint of thinning the adhesive layer, the adhesive used for laminating these films includes an aqueous one, that is, an adhesive component dissolved in water or dispersed in water. . For example, a composition using a polyvinyl alcohol resin or a urethane resin as a main component can be mentioned as a preferred adhesive. In addition, when bonding a film on both surfaces of a polarizing film, the same kind of adhesive agent may be used and a different kind of adhesive agent may be used, respectively.

  When a polyvinyl alcohol-based resin is used as the main component of the adhesive, the polyvinyl alcohol-based resin may be partially saponified polyvinyl alcohol, fully saponified polyvinyl alcohol, carboxyl group-modified polyvinyl alcohol, acetoacetyl group-modified polyvinyl alcohol, or methylol group. Modified polyvinyl alcohol resins such as modified polyvinyl alcohol and amino group-modified polyvinyl alcohol may also be used. In this case, an aqueous solution of a polyvinyl alcohol resin is used as the adhesive. The density | concentration of the polyvinyl alcohol-type resin in an adhesive agent is 1-10 weight part normally with respect to 100 weight part of water, Preferably it is 1-5 weight part.

  It is preferable to add a curable component such as glyoxal or a water-soluble epoxy resin and a crosslinking agent to the adhesive composed of an aqueous solution of a polyvinyl alcohol resin in order to increase the adhesiveness. As the water-soluble epoxy resin, for example, a polyamide polyamine epoxy resin obtained by reacting a polyalkylene polyamine such as diethylenetriamine or triethylenetetramine with a polycarboxylic acid such as adipic acid and epichlorohydrin. Can be suitably used. Commercially available products of such polyamide polyamine epoxy resins include Sumire's Resin 650 (manufactured by Sumika Chemtex Co., Ltd.), Sumire's Resin 675 (manufactured by Sumika Chemtex Co., Ltd.), WS-525 (manufactured by Nippon PMC Corporation). Etc. The addition amount of these curable component and crosslinking agent (when added together, the total amount) is usually 1 to 100 parts by weight, preferably 1 to 50 parts by weight with respect to 100 parts by weight of the polyvinyl alcohol resin. . When the addition amount of the curable component and the crosslinking agent is less than 1 part by weight with respect to 100 parts by weight of the polyvinyl alcohol-based resin, the effect of improving adhesiveness tends to be reduced, and the curable component, This is because the adhesive layer tends to be brittle when the addition amount of the crosslinking agent exceeds 100 parts by weight with respect to 100 parts by weight of the polyvinyl alcohol resin.

When a urethane resin is used as the main component of the adhesive, examples of suitable adhesive compositions include a mixture of a polyester ionomer type urethane resin and a compound having a glycidyloxy group. The polyester-based ionomer type urethane resin here is a urethane resin having a polyester skeleton, into which a small amount of an ionic component (hydrophilic component) is introduced. Such an ionomer-type urethane resin is suitable as a water-based adhesive because it is emulsified directly in water without using an emulsifier to form an emulsion.
Polyester ionomer type urethane resins are known per se. For example, JP-A-7-97504 describes an example of a polymer dispersant for dispersing a phenolic resin in an aqueous medium. In JP-A-2005-70140 (Patent Document 2) and JP-A-2005-208456 (Patent Document 4), a mixture of a polyester ionomer type urethane resin and a compound having a glycidyloxy group is used as an adhesive. A form in which a cycloolefin resin film is bonded to a polarizing film made of a polyvinyl alcohol resin is shown.

  As a method of laminating the above-mentioned stretched polyethylene terephthalate film (and a protective film or an optical compensation film, if necessary) to the polarizing film, generally known methods may be used. For example, casting method, Mayer bar coat Apply an adhesive to the adhesive surface of the polarizing film and / or the film to be bonded to it by the method, gravure coating method, comma coater method, doctor blade method, die coating method, dip coating method, spraying method, etc. The method to match is mentioned. The casting method is a method of spreading and spreading an adhesive on the surface of a film to be coated while moving it in a substantially vertical direction, a substantially horizontal direction, or an oblique direction between the two.

  After apply | coating an adhesive agent by the method mentioned above, a polarizing film and the film bonded by it are pinched | interposed by a nip roll etc., and are bonded together. Moreover, after dripping an adhesive agent between a polarizing film and the film bonded to it, the method of pressurizing this laminated body with a roll etc. and spreading it uniformly can also be used suitably. In this case, it is possible to use metal or rubber as the material of the roll. Furthermore, after dropping an adhesive agent between a polarizing film and the film bonded to it, the method of passing this laminated body between rolls and pressurizing and spreading is also preferably employed. In this case, these rolls may be made of the same material or different materials. The thickness of the adhesive layer after being bonded using the nip roll or the like before drying or curing is preferably 5 μm or less, and more preferably 0.01 μm or more.

  Further, in forming the adhesive layer, on the film surface to which the adhesive is applied, for example, the surface to be bonded to the polarizing film of the stretched polyethylene terephthalate film, or the surface to be bonded to the polarizing film of the protective film or the optical compensation film In order to improve adhesiveness, surface treatment such as plasma treatment, corona treatment, ultraviolet irradiation treatment, flame (flame) treatment, saponification treatment, etc. may be appropriately performed. Examples of the saponification treatment include a method of immersing in an aqueous alkali solution such as sodium hydroxide or potassium hydroxide.

  The laminated body joined via the aqueous adhesive is usually subjected to a drying treatment, and the adhesive layer is dried and cured. The drying process can be performed by blowing hot air, for example. The drying temperature is appropriately selected from the range of about 40 to 100 ° C, preferably 60 to 100 ° C. The drying time is, for example, about 20 to 1200 seconds. The thickness of the adhesive layer after drying is usually about 0.001 to 5 μm, preferably 0.01 μm or more, preferably 2 μm or less, more preferably 1 μm or less. If the thickness of the adhesive layer becomes too large, the appearance of the polarizing plate tends to be poor.

  After the drying treatment, sufficient adhesive strength may be obtained by performing curing at a temperature of room temperature or higher for at least half a day, usually several days or longer. Such curing is typically performed in a state of being wound into a roll. A preferable curing temperature is in the range of 30 to 50 ° C, more preferably 35 ° C or more and 45 ° C or less. When the curing temperature exceeds 50 ° C., so-called “roll tightening” is likely to occur in the roll winding state. The humidity during curing is not particularly limited, but is preferably selected so that the relative humidity is in the range of about 0% RH to 70% RH. The curing time is usually about 1 to 10 days, preferably about 2 to 7 days.

  Moreover, a photocurable adhesive agent can also be used for the adhesive agent in the polarizing plate of this invention. As a photocurable adhesive agent, mixtures, such as a photocurable epoxy resin and a photocationic polymerization initiator, are mentioned, for example. In this case, the photocurable adhesive is cured by irradiating with active energy rays. The light source of the active energy ray is not particularly limited, but an active energy ray having a light emission distribution at a wavelength of 400 nm or less is preferable. Specifically, the low-pressure mercury lamp, the medium-pressure mercury lamp, the high-pressure mercury lamp, the ultrahigh-pressure mercury lamp, the chemical lamp, and the black light lamp A microwave excitation mercury lamp, a metal halide lamp and the like are preferable.

The light irradiation intensity to the photocurable adhesive is appropriately determined depending on the composition of the photocurable adhesive and is not particularly limited, but the irradiation intensity in the wavelength region effective for activating the polymerization initiator is 0.1 to 1000 mW. / Cm ² is preferable. When the light irradiation intensity is less than 0.1 mW / cm ² , the curing reaction time becomes long, that is, it does not cure unless a long irradiation time is applied, which may be disadvantageous from the viewpoint of improving productivity. On the other hand, if it exceeds 1000 mW / cm ² , yellowing of the composition and deterioration of the polarizing film may occur due to heat radiated from the lamp and heat generated during polymerization of the composition.

The light irradiation time to the photocurable adhesive is controlled for each photocurable adhesive when cured and is not particularly limited, but the integrated light amount expressed as the product of the irradiation intensity and the irradiation time is It is preferably set to be 10 to 5000 mJ / cm ² . When the accumulated light amount to the photocurable adhesive is 10 mJ / cm ² or more, a sufficient amount of active species derived from the polymerization initiator can be generated to allow the curing reaction to proceed more reliably, and 5000 mJ / cm. ^{By being 2} or less, the irradiation time does not become too long, and good productivity can be maintained. In addition, the thickness of the adhesive bond layer after active energy ray irradiation is about 0.001-5 micrometers normally, Preferably it is 0.01 micrometer or more, Preferably it is 3 micrometers or less.

  When curing a photo-curable adhesive by irradiation with active energy rays, various functions of the polarizing plate, such as the degree of polarization, transmittance and hue of the polarizing film, and transparency of the stretched polyethylene terephthalate film, protective film, and optical compensation film It is preferable to perform the curing under the condition that does not decrease.

  The polarizing plate of the present invention has an outer surface opposite to the side on which the stretched polyethylene terephthalate film of the polarizing film is laminated (if the protective film or the optical compensation film is laminated, the polarization of the protective film or the optical compensation film). A pressure-sensitive adhesive layer for bonding the polarizing plate to the liquid crystal cell is preferably formed on the surface opposite to the side laminated on the film. As the pressure-sensitive adhesive used for such a pressure-sensitive adhesive layer, a conventionally known appropriate pressure-sensitive adhesive can be used without particular limitation, and examples thereof include an acrylic pressure-sensitive adhesive, a urethane pressure-sensitive adhesive, and a silicone pressure-sensitive adhesive. Among these, an acrylic pressure-sensitive adhesive is preferably used from the viewpoints of transparency, adhesive strength, reliability, reworkability, and the like. The pressure-sensitive adhesive layer can be provided by a method in which such a pressure-sensitive adhesive is used, for example, in the form of an organic solvent solution, which is applied to a base film with a die coater or a gravure coater, and dried. It can also be provided by a method of transferring a sheet-like pressure-sensitive adhesive formed on a plastic film to which the above has been applied to a base film. Although there is no restriction | limiting in particular also about the thickness of an adhesive layer, Generally it is preferable to exist in the range of 2-40 micrometers.

  An optical functional film may be attached to the outer surface of the polarizing plate via the pressure-sensitive adhesive layer. Examples of the optical functional film include, in addition to the above-described optical compensation film based on the cellulose-based film or the cycloolefin-based film, an optical compensation film in which a liquid crystal compound is applied to the substrate surface and oriented, A reflective polarizing film that transmits certain types of polarized light and reflects polarized light that exhibits the opposite properties, a retardation film made of polycarbonate resin, a film with an antiglare function that has an uneven surface, and a surface antireflection treatment Examples thereof include an attached film, a reflective film having a reflective function on the surface, and a transflective film having both a reflective function and a transmissive function. Commercially available products corresponding to an optical compensation film coated with a liquid crystal compound on the substrate surface and oriented are WV film (Fuji Film Co., Ltd.), NH film (Shin Nippon Oil Co., Ltd.), NR Examples include films (manufactured by Nippon Oil Corporation). For example, DBEF (manufactured by 3M, available from Sumitomo 3M Co., Ltd. in Japan) is a commercially available product that corresponds to a reflective polarizing film that transmits certain types of polarized light and reflects polarized light that exhibits the opposite properties. Etc. Moreover, as a commercial item corresponding to the retardation film which consists of cyclic polyolefin resin, for example, Arton Film (made by JSR Corporation), Essina (made by Sekisui Chemical Co., Ltd.), Zeonoor Film (made by Optes Co., Ltd.) Etc.

  On the outermost surface of the polarizing plate, a surface protective film having a pressure-sensitive adhesive layer was used for the purpose of preventing damage to the protective film and adhesion of dust, and when the pressure-sensitive adhesive layer was formed on the polarizing plate, a release treatment was performed. A surface protective film can be provided.

  Examples of the constituent material of the surface protective film include polyethylene, polypropylene, polyester, etc. Among them, a stretched film of polyethylene terephthalate is preferable from the viewpoint of moisture permeability and mechanical strength.

  The method for producing the surface protective film is arbitrary and is not particularly limited, and the same one as the stretched polyethylene terephthalate film laminated on the polarizing film of the present invention may be used, or a different one may be used. . However, these surface protective films are finally peeled off, but may be performed in the state of being imparted at the time of inspection of the polarizing plate, particularly when the constituent material of the surface protective film is drawn polyethylene terephthalate. From the viewpoint of inspection properties, the maximum value of the distortion of the orientation main axis is preferably 15 degrees or less, like the stretched polyethylene terephthalate film used in the present invention.

  The pressure-sensitive adhesive layer applied to the surface protective film is not particularly limited, and an appropriate polymer such as an acrylic polymer, silicone polymer, polyester, polyurethane, polyamide, polyether, fluorine-based or rubber-based polymer is used as the base polymer. Can be used as

  The release treatment layer applied to the surface protective film is not particularly limited as long as it has releasability, and may be a type mainly composed of a curable silicone resin, a urethane resin, an epoxy. A modified silicone type obtained by graft polymerization with an organic resin such as a resin or an alkyd resin may be used. Among them, a type mainly composed of a curable silicone resin is preferable. Moreover, it does not specifically limit about formation on a surface protection film, It can carry out by a suitable method.

  The present invention also provides a liquid crystal display device including a liquid crystal panel in which the above-described polarizing plate of the present invention is bonded to a liquid crystal cell via an adhesive layer. In this case, the polarizing plate of the present invention is bonded to the back side or the front side of the liquid crystal cell, or to the back side and the front side. In the liquid crystal display device of the present invention, for the portions other than the above-described features, an appropriate configuration of a conventionally known liquid crystal display device can be adopted, and the configuration requirements (light diffusing plate) that the liquid crystal display device normally includes other than the liquid crystal panel , Backlight, etc.) are not particularly limited.

  The light diffusing plate is an optical member having a function of diffusing light from a backlight. For example, a light diffusing agent is provided by dispersing particles as a light diffusing agent in a thermoplastic resin, Used are those in which irregularities are formed on the surface of a plastic resin plate to impart light diffusibility, and a coating layer of a resin composition in which particles are dispersed is provided on the surface of a thermoplastic resin plate to impart light diffusibility. It is done. The thickness of the light diffusion plate is not particularly limited, but is preferably in the range of 0.1 to 5 mm. Further, between the light diffusion plate and the liquid crystal panel, a prism sheet (also called a condensing sheet, such as BEF (manufactured by 3M), etc.), a brightness enhancement sheet (same as the above-described reflective polarizing film). It is also possible to dispose a sheet exhibiting other optical functionality, such as a light diffusion sheet (such as DBEF described above). A plurality of types of sheets exhibiting other optical functionalities can be arranged as necessary. Further, as the light diffusing plate, for example, a light diffusing function such as a laminated integrated product of a prism sheet having a cylindrical shape on the surface and a light diffusing plate (for example, those described in JP-A-2006-284497) It is also possible to use an optical sheet in which other functions are combined.

  The polarizing plate of the present invention is suitably used in the configuration of backlight / light diffusion plate / light diffusion sheet / brightness enhancement sheet / liquid crystal cell. The “rear side” of the liquid crystal cell and liquid crystal panel described above means the backlight side when the liquid crystal panel is mounted on the liquid crystal display device, and the “front side” of the liquid crystal cell and liquid crystal panel means the liquid crystal panel. Means the viewing side when mounted on a liquid crystal display device.

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples. In the examples, “%” and “part” representing the content or amount used are based on weight unless otherwise specified. In the following examples, the in-plane retardation value R ₀ and the thickness direction retardation value R _th of an optical compensation film made of a stretched norbornene resin are values measured using KOBRA 21ADH (manufactured by Oji Scientific Instruments). Point to. Moreover, the shift | offset | difference angle and MOR with respect to the extending | stretching axis | shaft of the orientation main axis | shaft of a stretched polyethylene terephthalate film point out the value measured using the microwave transmission type | mold molecular orientation meter (Oji Scientific Instruments Co., Ltd. product).

<Example 1>
A polyvinyl alcohol film having an average polymerization degree of about 2400 and a saponification degree of 99.9 mol% or more and a thickness of 75 μm was immersed in pure water at 30 ° C., and then the weight ratio of iodine / potassium iodide / water was 0.02 / 2. / 100 aqueous solution at 30 ° C. Then, it was immersed at 56.5 ° C. in an aqueous solution having a potassium iodide / boric acid / water weight ratio of 12/5/100. Subsequently, the film was washed with pure water at 8 ° C. and then dried at 65 ° C. to obtain a polarizing film in which iodine was adsorbed and oriented on polyvinyl alcohol. Stretching was mainly performed in the iodine staining and boric acid treatment steps, and the total stretching ratio was 5.3 times.

  On one side of the polarizing film obtained as described above, a stretched polyethylene terephthalate film having a thickness of 45 μm (a misalignment angle of the orientation main axis with respect to the stretching axis: 2 degrees, MOR: 3.4) is subjected to corona treatment on the bonding surface. After applying, adhesive bonding was carried out via a photocurable adhesive.

Next, on the opposite side of the polarizing film on which the stretched polyethylene terephthalate film is laminated, an optical compensation film (in-plane retardation value R ₀ : 63 nm, thickness direction retardation value R _{th) made of} a stretched norbornene resin having a thickness of 73 μm. : 225 nm) was subjected to a corona treatment on the bonding surface, and then adhered via a photocurable adhesive to obtain a polarizing plate. Using the polarizing plate obtained in this way and a polarizing film for inspection prepared separately, each polarizing film is placed so that the absorption axes of the polarizing films are perpendicular to each other, and then crossed nicols and irradiated with white light and visually observed. As a result, even when the stretched polyethylene terephthalate film side was sandwiched between polarizing films, visual inspection under crossed Nicols was possible. Further, an acrylic pressure-sensitive adhesive layer having a thickness of 25 μm is provided on the outer surface of the optical compensation film of the polarizing plate, and the outer surface side of the optical compensation film on which the pressure-sensitive adhesive layer is formed is disposed on the back surface of the liquid crystal cell. A commercially available polarizing plate (Sumikaran SRW842E-GL5, manufactured by Sumitomo Chemical Co., Ltd.) is placed on the front to assemble a liquid crystal panel, and using this, a commercially available backlight / light diffusion plate / diffusion sheet / diffusion sheet / brightness improvement A liquid crystal display device constituted in the order of sheet (DBEF) / liquid crystal panel was produced. When the obtained liquid crystal display device was visually observed, the color unevenness (interference unevenness) in the oblique direction was small, and the visibility was good.

<Example 2>
A polarizing plate was produced in the same manner as in Example 1 except that a stretched polyethylene terephthalate film having a misalignment angle with respect to the stretching axis of the orientation main axis of 5 degrees and MOR of 3.4 was used. Using this polarizing plate and a polarizing film for inspection prepared separately, each polarizing film was placed so that the absorption axes of the polarizing films were orthogonal to each other, crossed Nicol, and irradiated with white light and visually observed, and stretched polyethylene terephthalate. Even when the film side was sandwiched between polarizing films, visual inspection under crossed Nicols was possible. Further, a liquid crystal display device was produced using the polarizing plate. When the obtained liquid crystal display device was visually observed, the color unevenness (interference unevenness) in the oblique direction was small, and the visibility was good.

<Comparative Example 1>
A polarizing plate was produced in the same manner as in Example 1 except that a stretched polyethylene terephthalate film having a misalignment angle of 30 ° with respect to the stretching axis of the orientation main axis and MOR of 2.1 was used. Using this polarizing plate and a polarizing film for inspection prepared separately, each polarizing film was placed so that the absorption axes of the polarizing films were orthogonal to each other, crossed Nicol, and irradiated with white light and visually observed, and stretched polyethylene terephthalate. When the film side was sandwiched between polarizing films, it was optically coherent and could not be inspected. Further, a liquid crystal display device was produced using the polarizing plate. When the obtained liquid crystal display device was visually observed, color unevenness (interference unevenness) in an oblique direction was observed.

  It should be understood that the embodiments and examples disclosed herein are illustrative and non-restrictive in every respect. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning of the claims.

Claims (5)

  A polarizing film comprising a polyvinyl alcohol-based resin and a stretched polyethylene terephthalate film laminated on one side of the polarizing film via an adhesive layer, and a misalignment angle of the oriented principal axis of the stretched polyethylene terephthalate film with respect to the stretching axis is 15 degrees or less And a MOR value measured by a microwave transmission type molecular orientation meter is 1.5 or more.   The polarizing plate according to claim 1, further comprising a protective film or an optical compensation film laminated on a side opposite to the side on which the stretched polyethylene terephthalate film of the polarizing film is laminated.   The polarizing plate according to claim 1 or 2, wherein the stretched polyethylene terephthalate film laminated on the polarizing film has an antiglare layer on the outer surface thereof.   The polarizing plate according to claim 1, further comprising a pressure-sensitive adhesive layer on the outer surface opposite to the side on which the stretched polyethylene terephthalate film of the polarizing film is laminated.   A liquid crystal display device provided with the liquid crystal panel by which the polarizing plate of Claim 4 is bonded by the liquid crystal cell through the adhesive layer.