WO2020153566A1 - Polarizer and method for manufacturing same - Google Patents

Abstract

The present invention relates to a polarizer, a polarizing plate, and an image displaying device, wherein the orthogonal color value b is -1.0 or higher, and the ratio (A₄₅₀/A₇₀₀) between absorbance (A₄₅₀) at the wavelength of 450 mm and absorbance (A₇₀₀) at the wavelength of 700 mm is 2.5 or higher, so as to reduce the transmissivity of the blue light (a blue light source) wavelength band (of about 430 to 480 nm), thereby reducing the effect of blue light on a user. Further, the present invention relates to a method for manufacturing the polarizer.

Description

Polarizer and its manufacturing method

This application claims the benefit of priority based on Korean Patent Application No. 10-2019-0008906 dated January 23, 2019, and all contents disclosed in the documents of the Korean patent application are included as part of this specification.

The present invention relates to a polarizer and a manufacturing method thereof.

Blue light (Blue light) means a blue light of 380nm ~ 500nm among visible light, it has a characteristic that has a short wavelength and high energy.

These blue lights are originally emitted from the sun, and they emit the most during the day when the sun rises the most, and disappear completely when the sun goes down. During the day, they play a positive role in attention, reaction time, and emotion, but at night they destroy the biorhythms. It is known as.

These blue lights are also being emitted through liquid crystal screens of electronic devices such as smartphones, tablets, and computer monitors, which are rapidly spreading in recent years, especially considering that the number of users using electronic devices is increasing even in the dark. When it is dark, it is inevitably exposed to blue light even in the dark.

The blue light that is exposed to the user as described above causes adverse effects on the human body such as dry eye, eye fatigue, deterioration of eyesight, and deterioration of the retina, and also disturbs the body's biorhythms, causing sleep disorders due to disturbance of the melatonin hormone There is a problem that adversely affects the human body by causing.

Therefore, it is necessary to develop a technology that minimizes the influence of the blue light.

In this regard, Republic of Korea Patent No. 10-1395498 is attached to the liquid crystal screen of the electronic device to protect the liquid crystal screen of the electronic device and a glass layer provided with a bonding layer on the back surface; A first release layer provided at a position corresponding to the surface of the glass layer so as to adhere to the surface of the glass layer, and being adhered to the surface of the glass layer and falling from the surface of the adhered glass layer; A blue light blocking layer bonded to a bonding layer provided on the rear surface of the glass layer and blocking blue light emitted from the liquid crystal screen of the electronic device; The second adhesive layer is provided at a position corresponding to the back surface of the blue light blocking layer so as to adhere to the back surface of the blue light blocking layer, and the second adhesive layer is attached to the back surface of the blue light blocking layer and is detached from the back surface of the adhered blue light blocking layer. Although a technology that can prevent the harmful effects of blue light is disclosed by including a release layer, this is a structure in which a separate blue light blocking layer is stacked, so an additional process is required to increase the process time and decrease productivity. There is.

[Advanced technical literature]

[Patent Document]

Republic of Korea Registered Patent No. 10-1395498 (2014.05.14.)

The present invention is to solve this problem, and to provide a polarizer that can reduce the effect of blue light by suppressing the transmittance of the blue light wavelength band only by the polarizer itself without a separate additional process and a method for manufacturing the same do.

The polarizer of the present invention for achieving the above object has an orthogonal color b value of -1.0 or more, and a ratio (A ₄₅₀ /A ₇₀₀ ) of absorbance (A ₄₅₀ ) at a wavelength of ₄₅₀ nm and absorbance (A ₇₀₀ ) at a wavelength of 700 nm. Characterized by 2.5 or more.

In addition, the polarizing plate of the present invention is characterized by including the polarizer described above.

In addition, the image display device of the present invention is characterized by including the polarizing plate described above.

In addition, the polarizer manufacturing method of the present invention includes a swelling step, a dyeing step, a stretching step, a crosslinking step, a complementary color step, a pre-heat treatment step, a water washing step and a drying step, and the complementary color step comprises a boric acid compound and potassium iodide. Proceeding using a complementary liquid, it characterized in that the potassium iodide is included in 12 to 15% by weight relative to 100% by weight of the total complementary liquid.

The polarizer, polarizing plate, and image display device of the present invention has an advantage of reducing the influence of blue light by reducing the transmittance of the blue light wavelength band.

In addition, the method of manufacturing a polarizer of the present invention has an advantage of manufacturing a polarizer that satisfies the conditions presented to reduce the effect of blue light in the present invention.

1 and 2 show the transmittance test results for each wavelength of Examples and Comparative Examples of the present invention.

In the present invention, when a member is positioned "on" another member, this includes not only the case where one member is directly in contact with the other member but also another member interposed between the two members.

In the present invention, when a part “includes” a certain component, this means that other components may be further included, rather than excluding other components, unless otherwise specified.

Hereinafter, the present invention will be described in more detail.

<Polarizer>

The polarizer according to an aspect of the present invention has an orthogonal color b value of -1.0 or more, and a ratio (A ₄₅₀ /A ₇₀₀ ) of absorbance (A ₄₅₀ ) at a wavelength of ₄₅₀ nm and absorbance (A ₇₀₀ ) at a wavelength of 700 nm is 2.5 or more. By reducing the transmittance of the blue light (blue light source) wavelength band (about 430nm to 480nm) by characterized in that, there is an advantage that the user is reduced the effect of the blue light.

In the present invention, the orthogonal color means a color obtained when natural light is irradiated to two polarizers in which other polarizers are stacked on one polarizer so that the absorption axes are orthogonal to each other at right angles.

In addition, the orthogonal color b value refers to a value representing a color in the CIE coordinate system. More specifically, the b value is calculated by Equation 1 below, and +b means yellow or red, and -b means blue.( Here, Xn, Yn, and Zn correspond to X, Y, and Z of the white color as a reference.)

[Equation 1]

b = 200[(Y/Yn) ¹ / ^3- (Z/Zn) ^1/3 ]

That is, the orthogonal color b value means the color b value in the CIE coordinate system in which the color when the pair of polarizers are arranged in a state in which the absorption axes are orthogonal is measured using a color difference meter.

The polarizer according to an aspect of the present invention can implement a neutral black color by adjusting the orthogonal color b to -1 or more, and furthermore, it can block blue light more effectively by showing a red color toward +. There is an advantage. When the orthogonal color b shows a value lower than -1, the blue color may be improved and the inhibitory effect of the blue screen may be reduced.

The orthogonal color b may be preferably -1 to 10, more preferably 0 to 8, and even more preferably 0 to 5. When the orthogonal color b value is included in the above-described preferred range, the blue light blocking effect may be further improved.

The A ₄₅₀ and A ₇₀₀ mean absorbance in the lower portion of the absorption band on the short wavelength side (blue region) and absorbance in the lower portion of the absorption band on the long wavelength side (red region), respectively. In the above, the transmittance of blue light is adjusted by adjusting the ratio of A ₄₅₀ /A ₇₀₀ to 2.5 or more by improving the intensity of the absorbance of the short-wavelength side absorption band and further adjusting the absorbance of the long-wavelength side absorption band compared to the polarizer produced by increasing the transmittance of the conventional polarizing plate. This has a decreasing effect. The A ₄₅₀ /A ₇₀₀ may be preferably 2.5 to 7.0, more preferably 2.5 to 5.5, and when the A ₄₅₀ /A ₇₀₀ is included within the above-described preferred range, the blue light blocking effect is further improved. It has the advantage of being.

The A ₄₅₀ and A ₇₀₀ are values that can be measured using an absorbing photometer such as an ultraviolet visible spectrophotometer, and natural light is used for incident light. When the incident light intensity is To and the transmitted light intensity is T, the absorbances A ₄₅₀ and A ₇₀₀ are calculated by Equation 2 below.

[Equation 2]

Absorbance (A ₄₅₀ or A ₇₀₀ ) = -log(T/To)

In addition, if the incident light incident on the polarizer sample has polarization property, the obtained absorbance value may fluctuate depending on the orientation when the sample is set on the absorbance photometer. For example, depending on the absorbance photometer, some polarization may occur in the incident light due to the influence of a mirror or an optical element between the light source and the sample, or a polarization separation element such as a prism may be included. Need attention. In the case of using such an absorbing photometer, the polarizing plate is measured at a certain angle (meaning a certain orientation around the optical axis), then measured again at a 90-degree rotating orientation, and the absorbance is calculated by calculating the absorbance from their average transmitted light intensity. The influence of polarization can be eliminated.

The polarizer according to an embodiment of the present invention may have a single-vision transmittance (Ty) of 41% or more, and a polarization (Py) of 99% or more, preferably more than 99.960%, more preferably at a wavelength of 450 nm. It can be more than 99.970%. When the Ty and Py satisfy the above range, good clarity of the image can be ensured when it is applied to the image display device.

The luminous sensitivity corrected single transmittance (Ty) and the sensibility corrected polarized light (Py) mean that a sensitivity correction called a luminous sensitivity correction is applied to the simple transmittance and polarization obtained for each wavelength. The group transmittance and polarization degree are calculated by the following equations 3 or 4, respectively.

[Equation 3]

Simplex transmittance = 0.5 × [Tp(λ) + Tc(λ)]

[Equation 4]

Polarization = 100 × [(Tp(λ)-Tc(λ))/(Tp(λ) + Tc(λ))]]

In Equation 3 or 4, Tp(λ) is a transmittance (%) of a polarizing plate or a polarizer measured in a relationship between linear polarization of the incident wavelength λnm and parallel Nicole, and Tc(λ) is linear polarization of the incident wavelength λnm And the transmittance (%) of a polarizing plate or a polarizer measured in the relationship of orthogonal Nicole, and both refer to measurement values obtained by measuring a visible absorption spectrum of a polarizer by a spectrophotometer.

In addition, the luminous intensity corrected single transmittance (Ty) and the luminous intensity corrected polarization (Py) can be easily measured by, for example, an absorbance photometer (model number: V7100) manufactured by Nippon Bunko Co., Ltd.

The polarizer of the present invention may be one in which a dichroic dye is adsorbed and oriented on a uniaxially stretched polyvinyl alcohol-based resin layer.

As the polyvinyl alcohol-based resin constituting the polyvinyl alcohol-based resin layer, a saponified polyvinyl acetate-based resin can be used. Examples of the polyvinyl acetate-based resin include copolymers of vinyl acetate and other monomers copolymerizable therewith, in addition to polyvinyl acetate, which is a homopolymer of vinyl acetate. Other monomers copolymerizable with vinyl acetate include, for example, unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and acrylamides having ammonium groups.

Although not limited thereto, the polarizer may be a solution of the polyvinyl alcohol-based resin described above on the base film.

The polarizer may be stretched and oriented, and preferably may be stretched at a draw magnification of more than 5 times, more preferably more than 5 times and 17 times or less.

The saponification degree of the polyvinyl alcohol-based resin may be 80.0 mol% to 100.0 mol%, preferably 90.0 mol% to 99.5 mol%, and more preferably 94.0 mol% to 99.0 mol%. . When the saponification degree is less than 80.0 mol%, when the polarizing plate is manufactured, the water resistance and the moisture heat resistance of the polarizing plate may be lowered, and when a saponification degree of more than 99.5 mol% is used, a polyvinyl alcohol-based resin slows the dyeing rate and increases productivity. This may degrade, and may not be easy to obtain a polarizer having sufficient polarization performance.

At this time, the saponification degree is the ratio of the acetic acid group (acetoxy group: -OCOCH ₃ ) contained in the polyvinyl acetate-based resin, which is a raw material of the polyvinyl alcohol-based resin, changed to a hydroxyl group by the saponification process in unit ratio (mol%). As represented by, it is calculated by the following equation (5).

[Equation 5]

Saponification degree (mol%) = 100 × [(Number of hydroxyl groups) ÷ (Number of hydroxyl groups + Number of acetic acid groups)]

The saponification degree can also be obtained in accordance with JIS K 6726 (1994). The higher the degree of saponification, the higher the proportion of hydroxyl groups, and thus the lower the proportion of acetic acid groups that inhibit crystallization.

The polyvinyl alcohol-based resin may be a partially modified polyvinyl alcohol. For example, polyvinyl alcohol-based resins such as olefins such as ethylene and propylene; Unsaturated carboxylic acids such as acrylic acid, methacrylic acid and crotonic acid; What modified|denatured with the alkyl ester of an unsaturated carboxylic acid, acrylamide, etc. is mentioned. The denaturation ratio may be preferably less than 30 mol%, and more preferably less than 10%. When denaturation of more than 30 mol% is performed, it is difficult to adsorb the dichroic dye, and it may not be easy to obtain a polarizer having sufficient polarization performance.

The polyvinyl alcohol-based resin may have an average polymerization degree of preferably 100 to 10000, more preferably 1500 to 8000, and even more preferably 2000 to 5000. The average polymerization degree of the polyvinyl alcohol-based resin can also be obtained according to JIS K 6726 (1994).

Commercially available products of the polyvinyl alcohol-based resin include, for example, "PVA124" manufactured by Kurare Co., Ltd. (soap degree: 98.0 mol% to 99.9 mol%), and "PVA117" (desolubility degree: 98.0 mol% to 99.90. Mol%), "PVA624" (degree of saponification: 95.0 mol% to 96.0 mol%), "PVA617" (degree of saponification: 94.5 mol% to 95.5 mol%); ``AH-26'' (soap degree: 97.0 mol% to 98.8 mol%), ``AH-22'' (saponification degree: 97.5 mol% to 98.5 mol%), ``NH-18'' manufactured by Nippon Kosei Chemical Co., Ltd. (Degree of saponification: 98.0 mol% to 99.9 mol%), "N-300" (degree of saponification: 98.0 mol% to 99.9 mol%); ``JC-33'' by Nihon Sakubi and Pobal Co., Ltd. (soap level: 99.0 mol% or more), ``JM-33'' (soap level: 93.5 mol% to 95.5 mol%), ``JM-26'' (soap level) : 95.5 mol% to 97.5 mol%), ``JP-45'' (degree of saponification: 86.5 mol% to 89.5 mol%), ``JF-17'' (degradation degree: 98.0 mol% to 99.9 mol%), ``JF-17L ”(Degree of saponification: 98.0 mol% to 99.9 mol%), “JF-20” (degree of saponification: 98.0 mol% to 99.9 mol%), and the like.

The dichroic dye contained (adsorption orientation) in the polarizer may be iodine or a dichroic organic dye. Dichroic organic dyes are, for example, Red BR, Red LR, Red R, Pink LB, Rubin BL, Bordeaux GS, Sky Blue LG, Lemon Yellow, Blue BR, Blue 2R, Navy RY, Green LG, Violet LB, Violet B, Black H, Black B, Black GSP, Yellow 3G, Yellow R, Orange LR, Orange 3R, Scarlet GL, Scarlet KGL, Congo Red, Brilliant Violet BK, Supra Blue G, Supra Blue GL, Supra Orange GL, Direct Sky Blue, direct fast orange S, fast black, etc. are mentioned. As for the dichroic dye mentioned above, only 1 type may be used individually and 2 or more types may be used together.

The base film may be, for example, a film made of a thermoplastic resin. As a specific example, it is a film composed of a thermoplastic resin having light transmittance, preferably an optically transparent thermoplastic resin, such as, for example, a chain polyolefin resin (such as polypropylene resin) and a cyclic polyolefin resin (norbornene resin). Polyolefin resins; Cellulose-based resins such as triacetyl cellulose and diacetyl cellulose; Polyester resins such as polyethylene terephthalate and polybutylene terephthalate; Polycarbonate-based resins; (Meth)acrylic resins such as methyl methacrylate resin; Polystyrene-based resins; Polyvinyl chloride-based resins; Acrylonitrile-butadiene-styrene resin; Acrylonitrile-styrene resin; Polyvinyl acetate-based resins; Polyvinylidene chloride-based resins; Polyamide resins; Polyacetal resins; Modified polyphenylene ether-based resins; Polysulfone-based resins; Polyethersulfone-based resins; Polyarylate resins; Polyamideimide-based resin; And polyimide resins, but is not limited thereto.

<Polarizing plate>

The polarizing plate according to another aspect of the present invention has the advantage that the transmittance of the blue light is reduced by including the above-described polarizer. Specifically, the polarizing plate may be a protective film further bonded through an adhesive layer or an adhesive layer on at least one surface of the polarizer of the present invention, and may further include other optical layers as necessary.

Protection film

The protective film may be a thermoplastic resin, for example, a polyolefin-based resin such as chain polyolefin-based resin (polypropylene-based resin), cyclic polyolefin-based resin (norbornene-based resin, etc.); Cellulose ester-based resins such as cellulose triacetate and cellulose diacetate; Polyester resins such as polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate; Polycarbonate-based resins; (Meth)acrylic resin; Or it may be a transparent resin film made of a mixture, a copolymer, or the like.

The cyclic polyolefin-based resin is a generic term for a resin that is polymerized by using a cyclic olefin as a polymerization unit, for example, Japanese Patent Application Publication No. Hei1-240517, Japanese Patent Publication No. 3-14882, Japanese Patent Publication No.3-122137 And resins described in Japanese Patent Publications. Specific examples of cyclic polyolefin-based resins include ring-opening (co)polymers of cyclic olefins, addition polymers of cyclic olefins, copolymers of cyclic olefins with chain olefins such as ethylene and propylene (typically random copolymers), and unsaturated ones. And graft polymers modified with carboxylic acids and derivatives thereof, and hydrides thereof. Among them, a norbornene-based resin using norbornene-based monomers such as norbornene or polycyclic norbornene-based monomer is preferably used as the cyclic olefin.

The cyclic polyolefin-based resin can be purchased and used as a commercially available product. Examples of commercial products include the trade names "Topas" (available from Topas Advanced Polymers GmbH, available from Polyplastics Co., Ltd.), and "Atone" (JSR ( Manufacture), ``ZEONOR'' (manufactured by Nippon Zeon Co., Ltd.), ``ZEONEX'' (manufactured by Nippon Zeon Co., Ltd.), ``Apel'' (manufactured by Mitsui Kagaku Co., Ltd.), etc. Can be heard.

In addition, the enclosed annular shapes such as the brand names ``Essina'' (manufactured by Sekisui Kagaku Kogyo Co., Ltd.), ``SCA40'' (manufactured by Sekisui Kagaku Kogyo Co., Ltd.), and ``Zeno No film'' (manufactured by Nippon Zeon Co., Ltd.) A commercial product of a polyolefin-based resin film can also be used as a protective film.

The cellulose ester-based resin may be an ester of cellulose and fatty acids. Specific examples of the cellulose ester-based resin may include cellulose triacetate, cellulose diacetate, cellulose tripropionate, and cellulose dipropionate. In addition, those copolymers or those in which a part of hydroxyl groups are modified with other substituents can also be used. Among these, cellulose triacetate (triacetylcellulose: TAC) may be particularly preferable. Many products of cellulose triacetate are commercially available, and may be advantageous in terms of availability and cost. Examples of commercially available products of cellulose triacetate are, as brand names, ``FujiTak TD80'' (manufactured by Fujifilm Co., Ltd.), ``Fujitak TD80UF'' (manufactured by Fujifilm Co., Ltd.), and ``Fujitak TD80UZ'' (Fujifilm ( Note) manufactured, ``Fujitak TD40UZ'' (manufactured by Fujifilm Co., Ltd.), ``KC8UX2M'' (manufactured by Konica Minolta Opto Co., Ltd.), ``KC4UY'' (manufactured by Konica Minolta Opto Co., Ltd.) and the like.

The protective film may be a protective film having optical functions such as a retardation film and a brightness enhancing film. For example, a transparent resin film made of the above material can be used as a retardation film provided with an arbitrary retardation value by stretching (uniaxial stretching or biaxial stretching, etc.) or by forming a liquid crystal layer or the like on the film.

The polarizing plate may further include a surface treatment layer (coating layer) such as a hard coat layer, an antiglare layer, an antireflection layer, an antistatic layer, and an antifouling layer. The surface treatment layer may be formed on the surface of the protective film. The method for forming the surface treatment layer on the surface of the protective film is not particularly limited, and a known method can be used.

Adhesive layer

The adhesive forming the adhesive layer is not limited thereto, and an aqueous adhesive or a photocurable adhesive can be used.

Examples of the water-based adhesive include an adhesive comprising an aqueous polyvinyl alcohol-based resin, an aqueous two-component urethane emulsion adhesive, and the like. Among them, an aqueous adhesive composed of an aqueous polyvinyl alcohol-based resin solution can be suitably used.

As the polyvinyl alcohol-based resin, in addition to the vinyl alcohol homopolymer obtained by saponifying polyvinyl acetate, which is a homopolymer of vinyl acetate, a polyvinyl alcohol-based copolymer obtained by saponifying a copolymer of vinyl acetate and other monomers copolymerizable therewith Copolymers or modified polyvinyl alcohol-based polymers partially modified with these hydroxyl groups can be used.

The water-based adhesive may further include additives such as a polyhydric aldehyde, a water-soluble epoxy compound, a melamine-based compound, a zirconia compound, and a zinc compound. When a water-based adhesive is used, the thickness of the adhesive layer obtained therefrom may be usually 1 μm or less.

The bonding method using the water-based adhesive is not particularly limited. Examples include a method in which a water-based adhesive is uniformly applied or introduced on one bonding surface, the other is laminated on a coating surface by a roll or the like, and dried. Usually, the water-based adhesive, after preparation, may be applied under a temperature of 15 to 40°C, and the bonding temperature may be usually 15 to 30°C.

As described above, in the case of using the water-based adhesive, it may be preferable to perform a drying step after bonding, followed by drying to remove water contained in the water-based adhesive. Drying can be performed, for example, by introducing a film after bonding into a drying furnace, and the drying temperature (temperature of the drying furnace) may be preferably 30 to 90°C. If it is less than 30°C, peeling of the bonded bodies may be facilitated. , When the drying temperature exceeds 90°C, polarization performance of the joined body may be deteriorated by heat. The drying time may be, for example, 10 seconds to 1000 seconds.

After the drying process, it may be desirable to undergo a curing process for curing for 12 hours to 600 hours at a temperature of room temperature or slightly higher, for example, about 20 to 45°C. At this time, the curing temperature may be set lower than the drying temperature.

The photocurable adhesive refers to an adhesive that cures by irradiating active energy rays such as ultraviolet rays, for example, containing a polymerizable compound and a photopolymerization initiator, including a photoreactive resin, a binder resin, and a photoreactive crosslinking agent And the like.

Examples of the polymerizable compound include photopolymerizable monomers such as photocurable epoxy monomers, photocurable acrylic monomers, and photocurable urethane monomers, or oligomers derived from photopolymerizable monomers. As said photoinitiator, what contains the substance which generate|occur|produces active species, such as a neutral radical, an anion radical, and a cationic radical, by irradiation with active energy rays, such as ultraviolet rays, is mentioned. As a photocurable adhesive containing a polymerizable compound and a photopolymerization initiator, one containing a photocurable epoxy monomer and a photocationic polymerization initiator can be preferably used.

The bonding method using a photocurable adhesive is not particularly limited. For example, according to the flexible method, the Meyer bar coat method, the gravure coat method, the comma coater method, the doctor blade method, the die coat method, the dip coat method, the spraying method, etc. And a method of applying a photocurable adhesive to the bonding surface, polymerizing both of them, and sandwiching them with a nip roll or the like. The softening method is a method in which an adhesive is dropped and expanded on the bonding surface while moving the object to be coated in a substantially vertical direction, a substantially horizontal direction, or an inclined direction between the two. The thickness of the adhesive layer after being bonded using a nip roll or the like, before drying or curing may be preferably 0.01 to 5 μm.

In the case of using the photocurable adhesive, after performing the above-mentioned bonding, a drying step is performed as necessary (in the case where the photocurable adhesive contains a solvent, etc.), and then a curing step of curing the photocurable adhesive by irradiating active energy rays This can be done. 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 may be preferable, specifically, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultra high pressure mercury lamp, a chemical lamp, and a black light lamp. , Microwave excitation mercury lamps, metal halide lamps and the like can be preferably used.

The light irradiation intensity to the photo-curable adhesive can be appropriately determined according to the composition of the photo-curable adhesive, and the irradiation intensity of the wavelength region effective for activation of the polymerization initiator is set to be 0.1 ㎽/cm 2 to 6000 ㎽/cm 2 It may be desirable. When the irradiation intensity is included within the above range, the reaction time may not be too long, so efficiency may be improved, and yellowing of the photocurable adhesive or deterioration of the polarizer may occur due to heat radiated from the light source and curing of the photocurable adhesive. Can be prevented.

The light irradiation time to the photo-curable adhesive can also be appropriately determined depending on the composition of the photo-curable adhesive, and is set so that the integrated light amount represented by the product of the irradiation intensity and the irradiation time is 10 mJ/cm 2 to 10000 mJ/cm 2 It may be desirable. When the integrated light amount is included in the above range, a sufficient amount of active species derived from the polymerization initiator is generated to cure the curing reaction more reliably, and the irradiation time is not excessively long, so that good productivity can be maintained.

Adhesive layer

The above-mentioned polarizing plate may further include an adhesive layer, for example, an adhesive layer may be used to stack the above-described polarizing plate on another component layer such as a liquid crystal cell.

The pressure-sensitive adhesive forming the pressure-sensitive adhesive layer is, for example, a (meth)acrylic-based resin, a styrene-based resin, a silicone-based resin or the like as a base polymer, to which an isocyanate compound, an epoxy compound, an aziridine compound and a crosslinking agent are added. It may be made of a composition, and may also be a pressure-sensitive adhesive layer containing fine particles to exhibit light scattering properties.

The method of forming the pressure-sensitive adhesive layer is not particularly limited, and a protective film surface or a polarizer surface is coated with a pressure-sensitive adhesive composition (adhesive solution) containing each component including the base polymer, and dried to form a pressure-sensitive adhesive layer. Alternatively, after the pressure-sensitive adhesive layer is formed on the separator (peel film), the pressure-sensitive adhesive layer may be transferred to a protective film surface or a polarizer surface. When the pressure-sensitive adhesive layer is formed on the protective film surface or the polarizer surface, surface treatment, for example, corona treatment or the like, may be performed on the protective film surface or the polarizer surface or on one or both sides of the pressure-sensitive adhesive layer.

Optical layer

The polarizing plate of the present invention may further include other optical layers.

As another optical layer, a reflective polarizer which transmits some kind of polarized light and reflects polarized light exhibiting properties opposite thereto; A film having an anti-glare function having an uneven shape on the surface; A film having a surface antireflection function; A reflective film having a reflective function on the surface; A semi-transmissive reflective film having both a reflection function and a transmission function; And a viewing angle compensation film, but are not limited thereto.

As a commercial item corresponding to a reflective polarizer that transmits a certain kind of polarized light and reflects polarized light exhibiting properties opposite thereto, for example, "DBEF" (manufactured by 3M, obtained from Sumitomo 3M Co., Ltd. in Japan) Possible), "APF" (manufactured by 3M, available from Sumitomosurim Co., Ltd. in Japan).

Examples of the viewing angle compensation film include an optical compensation film in which a liquid crystal compound is coated on a surface of a substrate and aligned and fixed, a retardation film made of a polycarbonate-based resin, a retardation film made of a cyclic polyolefin-based resin, and the like.

As a commercial item corresponding to the optical compensation film in which a liquid crystal compound is coated on the surface of the base material and is aligned and fixed, "WV film" (manufactured by Fuji Film Co., Ltd.) and "NH film" (JX Nikko Nisekene Industries Co., Ltd. ) Production), "NR film" (manufactured by JX Nikko Niseki Energy Co., Ltd.) and the like.

As commercial products corresponding to the retardation film made of the cyclic polyolefin-based resin, "Aton Film" (manufactured by JSR Corporation), "Essina" (manufactured by Sekisui Chemical Co., Ltd.), "Zeonoa Film" (Nippon Zeon) And manufactured by Co., Ltd.).

<Image display device>

The image display device according to another aspect of the present invention has an advantage in that the blue light blocking effect is excellent by including the above-described polarizing plate, so that the user can reduce the influence of the blue light.

The image display device may be configured by attaching the aforementioned polarizing plate to one or both sides of the display panel, and the display panel may be, for example, a liquid crystal panel, a plasma panel, an organic light emitting panel, and a quantum dot panel. The image display device may be a liquid crystal display (LCD), a plasma display panel (PDP), an organic light emitting diode (OLED), and a quantum dot display (Quantum Dot Display). Can.

More specifically, the image display device may be a liquid crystal display device including a liquid crystal panel and polarizing plates provided on both sides of the liquid crystal panel, wherein at least one of the polarizing plates is a polarizing plate including the polarizer according to the present invention. Can.

At this time, the type of the liquid crystal panel included in the liquid crystal display device is not particularly limited. For example, the panel is not limited to the type, and is a passive matrix type panel such as a twisted nematic (TN) type, a super twisted nematic (STN) type, a ferroelectic (F) type, or a polymer dispersed (PD) type; An active matrix panel such as a two-terminal type or a three-terminal type; All well-known panels, such as an In-plane Switching (IPS) panel and a Vertical Alignment (VA) panel, can be applied. In addition, other configurations constituting the liquid crystal display device, for example, types of upper and lower substrates (ex. color filter substrates or array substrates) are also not particularly limited, and configurations known in this field may be employed without limitation. Can.

<Manufacturing method of polarizer>

The present invention also provides a method of manufacturing a polarizer.

Method of manufacturing a polarizer according to another aspect of the present invention includes a swelling step, a dyeing step, a stretching step, a crosslinking step, a complementary color step, a pre-heat treatment step, a water washing step and a drying step, wherein the complementary color step is a boric acid compound and potassium iodide Proceeding by using a complementary liquid containing a, orthogonal color b value is -1,0 or more, characterized in that the potassium iodide is included in 12 to 15% by weight relative to the total 100% by weight of the complementary liquid, the wavelength There is an advantage in that a ratio (A ₄₅₀ /A ₇₀₀ ) of absorbance at ₄₅₀ nm (A ₄₅₀ ) and absorbance at wavelength 700 (A ₇₀₀ ) (A ₄₅₀ /A ₇₀₀ ) is 2.5 or more.

Polarizer Forming film

The film for forming the polarizer is not particularly limited as long as it is a dichroic material, that is, a film that can be dyed with iodine, for example, polyvinyl alcohol film, partially gummed polyvinyl alcohol film; Hydrophilic polymer films such as polyethylene terephthalate films, ethylene-vinyl acetate copolymer films, ethylene-vinyl alcohol copolymer films, cellulose films, partially gummed films thereof, and the like; Or a polyene-oriented film such as a polyvinyl alcohol-based film dehydrated and a polyvinyl alcohol-based film treated with dehydrochloric acid. Among them, a polyvinyl alcohol-based film may be preferable in that it has an excellent effect of enhancing the uniformity of polarization degree in the plane, and has excellent dyeing affinity for iodine.

The thickness of the polarizer forming film is not particularly limited, and may be, for example, 5 to 100 μm, and preferably 20 to 80 μm.

Swelling stage

A method of manufacturing a polarizer according to an aspect of the present invention includes a swelling step.

The swelling step is immersed in a swelling bath filled with an aqueous solution for swelling prior to dyeing the unstretched polarizer forming film, thereby removing impurities such as dust or anti-blocking agents deposited on the surface of the polarizer forming film and removing the polarizer forming film. It is a step to improve physical properties of the polarizer by swelling to improve the stretching efficiency and prevent staining non-uniformity.

As an aqueous solution for swelling, water (pure water, deionized water) can be used alone, and when a small amount of glycerin or potassium iodide is added thereto, swelling of the polymer film and workability can also be improved.

The content of glycerin and potassium iodide is not particularly limited, and may be, for example, 5% by weight or less and 10% by weight or less, respectively, of the total weight of the aqueous solution for swelling.

The temperature of the swelling bath is not particularly limited, and may be, for example, 0 to 60°C, and preferably 10 to 50°C. When the temperature of the swelling tank is within the above range, the stretching and dyeing efficiency is excellent afterwards, and expansion of the film due to excessive swelling can be prevented.

Dyeing steps

A method of manufacturing a polarizer according to an aspect of the present invention includes a dyeing step.

The dyeing step is a step of adsorbing iodine to the polarizer forming film by immersing the polarizer forming film in a dyeing tank filled with a dichroic material, for example, a dye containing iodine.

The dyeing solution may further include water, a water-soluble organic solvent, or a mixed solvent and iodine. The concentration of iodine may be 0.4 to 400 mmol/L in the dyeing solution, preferably 0.8 to 275 mmol/L, and more preferably 1 to 200 mmol/L.

The dyeing solution may further include iodide as a dissolution aid for improving dyeing efficiency.

The type of iodide is not particularly limited, and examples thereof include potassium iodide, lithium iodide, sodium iodide, zinc iodide, aluminum iodide, lead iodide, copper iodide, barium iodide, barium iodide, calcium iodide, titanium iodide, and the like. , Potassium iodide is preferred in view of its high solubility in water. These may be used alone or in combination of two or more.

The content of the iodide is not particularly limited, and for example, may be 0.01 to 10% by weight of the total weight of the dyeing solution, preferably 0.1 to 5% by weight.

The dyeing solution may further include a boric acid compound. The dyeing solution may include a boric acid compound to improve the retention time of the boric acid compound before performing the crosslinking reaction, thereby increasing the rate of complexing of the dichroic material on the polarizer forming film. Accordingly, color durability of the polarizer may be improved, and polarization degree may be improved.

The concentration of the boric acid compound in the dyeing solution is not particularly limited, but may be, for example, 0.1 to 5% by weight of the total weight of the dyeing solution, and preferably 0.3 to 3% by weight. When the concentration of the boric acid compound in the dyeing solution is less than 0.1% by weight, the effect of the increase in iodine complex formation decreases, and when it exceeds 5% by weight, cutting may occur due to an increase in stress.

The type of the boric acid compound is not particularly limited. For example, the boric acid compound may include boric acid, sodium borate, potassium borate, lithium borate, and the like, preferably boric acid. These may be used alone or in combination of two or more.

The temperature of the dyeing bath is not particularly limited, and may be, for example, 5 to 42°C, and preferably 10 to 35°C.

The time for immersing the film for forming a polarizer in the dyeing tank is not particularly limited, and may be, for example, 1 to 20 minutes, and preferably 2 to 10 minutes.

The stretching step may be performed together with the dyeing step, in which case the stretching ratio may be 1.01 to 2.0 times, preferably 1.1 to 1.8 times.

In addition, the cumulative stretching ratio of the polarizer up to the swelling and stretching step is preferably 1.2 to 4.0 times. When the cumulative stretching ratio is less than 1.2 times, wrinkles may occur on the film, and when it exceeds 4.0 times, initial optical properties may be deteriorated.

Bridge step

A method of manufacturing a polarizer according to an aspect of the present invention includes a crosslinking step.

The crosslinking step is a step of fixing the adsorbed iodine molecule by immersing the dyed polarizer-forming film in the crosslinking solution so that the dyeability by the iodine molecule that is physically adsorbed is not lowered by the external environment.

The crosslinking solution contains a boric acid compound. The crosslinking solution may include a boric acid compound, thereby improving crosslinking efficiency to suppress wrinkles in the film during the process, and to form an orientation of a dichroic material to improve optical properties.

Dichroic dyes are not often eluted in a humid environment, but when iodine cross-linking reaction is unstable, iodine molecules are often dissolved or sublimed depending on the environment, and sufficient cross-linking reaction is required.

The crosslinking step may be performed as a first crosslinking step and a second crosslinking step, and a boric acid compound may be included in the crosslinking solution used in at least one of the crosslinking steps.

The concentration of the boric acid compound in the crosslinking liquid is 1 to 4.5% by weight, and preferably 1.5 to 3.8% by weight, based on 100% by weight of the total crosslinking solution. When the concentration of the boric acid compound in the number of crosslinking solutions is less than 1% by weight, the polarization degree may be lowered, and when it exceeds 4.5% by weight, shrinkage may be increased.

At this time, the boric acid compound may be the same one used in the dyeing step.

The crosslinking solution may include water used as a solvent and an organic solvent that is mutually soluble together with water, and further include a small amount of potassium iodide to prevent uniformity of polarization degree within the polarizer surface and desorption of dyed iodine. Can.

The concentration of potassium iodide in the crosslinking solution is 1 to 15% by weight, preferably 5 to 11% by weight, based on 100% by weight of the total crosslinking solution. If the concentration of potassium iodide in the crosslinking solution is less than 1% by weight, polarization may decrease, and if it exceeds 15% by weight, heat resistance may deteriorate, resulting in reddening when exposed to high temperature for a long time.

In addition, the crosslinking solution may further include the above-mentioned iodide within the scope of not impairing the object of the present invention.

The temperature of the crosslinking bath is not particularly limited, but may be, for example, 20 to 70°C, and preferably 40 to 60°C.

The time for immersing the film for forming the polarizer in the crosslinking bath is not particularly limited, and may be, for example, 1 second to 15 minutes, and preferably 5 seconds to 10 minutes.

The stretching step may be performed together with the crosslinking step, and in this case, the stretching ratio of the first crosslinking step may be 1.4 to 3.0 times, and preferably 1.5 to 2.5 times. In addition, the stretching ratio of the second crosslinking step may be 1.01 to 2.0 times, and preferably 1.2 to 1.8 times.

The cumulative stretching ratio of the first crosslinking step and the second crosslinking step may be 1.5 to 5.0 times, and preferably 1.7 to 4.5 times. When the cumulative stretching ratio is less than 1.5 times, the synergistic effect of the crosslinking efficiency may be insufficient, and when it exceeds 5.0 times, the film may break due to excessive stretching and production efficiency may be reduced.

Complementary steps

A method of manufacturing a polarizer according to an aspect of the present invention includes a complementary color step.

The complementary color step is a step of additionally immobilizing the iodine molecule that is lacking in the crosslinking step.

The complementary solution used in the complementary color step of the present invention includes a boric acid compound. The complementary liquid may contain a boric acid compound to improve crosslinking efficiency to suppress wrinkles in the film during the process and to form an orientation of a dichroic material to improve optical properties.

The concentration of the boric acid compound in the complementary solution is 0.5 to 3% by weight, preferably 1 to 2.5% by weight, relative to 100% by weight of the total complementary solution.

If the concentration of the boric acid compound in the complementary solution is less than 0.5% by weight, polarization may be lowered, and if it is more than 3% by weight, shrinkage may be increased.

The details of the boric acid compound may be the same as described above in the dyeing step.

The complementary solution may include water used as a solvent and an organic solvent that is mutually soluble together with water, and further include a small amount of potassium iodide to prevent uniformity of polarization degree within the polarizer surface and desorption of dyed iodine. Can.

According to an aspect of the present invention, the concentration of potassium iodide in the complementary solution is 12 to 15% by weight, preferably 13 to 15% by weight, relative to 100% by weight of the total of the complementary solution including the same. When the concentration of the potassium iodide is included in the above-mentioned range, the orthogonal color b value of the present invention is -1.0 or more, and the absorbance at wavelength 450nm (A ₄₅₀ ) and the absorbance at wavelength 700nm (A ₇₀₀ ) It is possible to produce a photon having a ratio (A ₄₅₀ /A ₇₀₀ ) of 2.5 or more, and if the concentration of potassium iodide is less than 12% by weight, a short wavelength side absorbance is insufficient and thus a problem that does not reach the polarization degree required by the present invention occurs. , If it exceeds 15% by weight, the absorbance of the long wavelength side is excessively reduced, making it difficult to adjust the color of the polarizing plate.

In addition, the complementary liquid may further include the aforementioned iodide within the scope of not impairing the object of the present invention.

The temperature of the complementary tone is not particularly limited, but may be, for example, 20 to 70°C, and preferably 40 to 60°C.

The time for immersing the film for forming the polarizer in the complementary tone is not particularly limited, and may be, for example, 1 second to 15 minutes, and preferably 5 seconds to 10 minutes.

The stretching step may be performed together with the complementary color step, and in this case, the stretching ratio of the complementary color step may be 1 to 1.15 times, and preferably 1.01 to 1.1 times.

The cumulative stretching ratio of the complementary color step may be 1.5 to 7 times, and preferably 1.7 to 6 times. When the cumulative stretching ratio is less than 1.5 times, the synergistic effect of the crosslinking efficiency may be insufficient, and when it exceeds 7 times, the film may break due to excessive stretching and production efficiency may decrease.

Pre-heat treatment step

The method of manufacturing a polarizer according to an embodiment of the present invention may further include a pre-heat treatment step, and in the case of further including a pre-heat treatment step, the manufacture of the polarizer is more advantageous.

The pre-heat treatment step may be performed between a complementary color step and a water washing step.

The pre-heat treatment step further promotes additional crosslinking of boric acid (increased crosslinking in the molecule of the polymer), thereby increasing the formation of iodine complex space in the film for forming a polarizer (for example, polyvinyl alcohol) of the film for forming a polarizer. -I3 complex amount can be increased. Accordingly, the orthogonal b value can be improved to improve color, suppress staining, and improve polarization. It is also possible to secure the water washing margin in the washing step, which will be described later, which will be described later in detail.

The heating method in the pre-heat treatment step is not particularly limited, and known methods such as natural drying, heating drying, microwave drying, hot air drying, and infrared rays may be used, but irradiation with infrared rays is performed by promoting the crosslinking. It may be desirable in terms of improvement in color, staining, polarization, and the like.

According to one embodiment of the present invention, the amount of infrared radiation per unit volume of the film for forming the polarizer may be 1000 to 3000 J/cm ³ , preferably 1200 to 2500 J/cm ³ , more preferably 1800 To 2200J/cm ³ . As such, when the amount of infrared radiation is included within the above-described range, the orthogonal color b value may be further improved, and the visibility correction simplex transmittance (Ty) and the visibility correction polarization (Py) value at a wavelength of 450 nm may be further improved. There is an advantage.

The amount of heat received by the polarizer forming film may be adjusted by changing the heat treatment temperature, distance from the heat source, output, wavelength of the heat source, and heat treatment time, but is not limited thereto.

The time for performing the pre-heat treatment step is not particularly limited, and may be, for example, 0.1 minutes to 10 minutes, preferably 0.1 minutes to 5 minutes, and more preferably 0.1 minutes to 1 minute.

When the pre-heat treatment step is performed by irradiating infrared rays as described above, the wavelength of infrared rays may be 1 to 5 μm. If the wavelength of infrared rays is less than 1 μm, the boric acid crosslinking improvement and the color improvement effect may be insignificant, and if it exceeds 5 μm, yellowing of the film for forming a polarizer may be caused. In terms of the boric acid crosslinking enhancement effect and yellowing inhibition, it may be more preferably 1.5 to 3 μm.

Washing step

A method of manufacturing a polarizer according to an aspect of the present invention includes a washing step.

The water washing step is a step of removing unnecessary residues such as boric acid attached to the film for forming a polarizer in the previous steps by immersing the film for forming a polarizer having cross-linking and stretching in a water bath filled with an aqueous solution for washing.

The aqueous solution for washing with water may be water (deionized water), and iodide may be further added thereto. As the iodide, the same one used in the dyeing step may be used, and among these, it may be preferable to use sodium iodide or potassium iodide. The content of iodide is not particularly limited, and may be, for example, 0.1 to 10 parts by weight of the total weight of the aqueous solution for washing, preferably 3 to 8 parts by weight.

According to one embodiment of the present invention, the temperature of the water bath may be 4°C or more and less than 18°C, more preferably 8°C to 15°C, and more preferably 10°C to 13°C. If the water washing temperature does not reach the above range, the color value may deviate from the range of the present invention toward the yellow or red color, and if it exceeds the above range, the orthogonal color b value may decrease.

When the film for forming the polarizer is exposed to water for a long time, the polymer (e.g., polyvinyl alcohol)-I3 complex may be excessively converted to the polymer-I5 complex, resulting in problems such as orthogonal b-value deterioration and color change. Can occur. Accordingly, in the manufacture of the polarizer, water washing is performed within a short time to reduce the loss of the I3-containing complex, and foreign matter may remain on the film for forming the polarizer even after water washing.

However, when the above-described pre-heat treatment step is further included in the method for manufacturing a polarizer as in one embodiment of the present invention, the amount of the I3-containing complex is increased, so that the film for forming a polarizer can be washed more sufficiently than in the prior art. Accordingly, there is an advantage that a polarizer having a smaller amount of foreign matter can be produced.

The washing step may also be performed whenever previous steps such as a dyeing step, a crosslinking step or a stretching step are completed. Further, it may be repeated one or more times, and the number of repetitions is not particularly limited.

Drying step

A method of manufacturing a polarizer according to an aspect of the present invention includes a drying step.

The drying step is a process of drying the washed film for forming a polarizer and at the same time improving the orientation of the dyed iodine molecules to improve optical properties and impart durability.

The heating method in the drying step is not particularly limited, and known methods such as natural drying, heating drying, microwave drying, hot air drying, and infrared rays can be used.

The treatment temperature of the drying step is not particularly limited, and may be, for example, 60 to 120°C. The drying step may be performed, for example, for 30 seconds to 5 minutes, but is not limited thereto.

The surface temperature of the film for forming a polarizer to be dried is preferably a temperature capable of resolving the internal stress to the maximum, and may be, for example, 50 to 100°C. In the above range, it is possible to prevent deterioration of the film polymer and at the same time further improve the effect of reducing internal stress. When the temperature of the film is less than 50°C, the internal stress relieving effect may be insignificant, and when it exceeds 100°C, the film may deteriorate.

The stretching ratio in the drying step is not particularly limited, for example, the stretching ratio may be 0.95 to 1.0 times, and preferably 0.96 to 0.99 times.

According to one embodiment of the present invention, the stretching ratio of the drying step may be 0.96 times or more and less than 0.99 times, and more preferably 0.97 times to 0.98 times. When the stretching ratio of the drying step does not reach the above range, a problem may occur due to sagging of the film or a decrease in optical properties due to insufficient stretching, and when it exceeds the above range, a fracture due to excessive stress increase may occur. Can be.

According to an aspect of the present invention, when the polarizer is manufactured by the above-described method of manufacturing the polarizer, the orthogonal color b value is -1.0 or more, and the absorbance at wavelength 450nm (A ₄₅₀ ) and the absorbance at wavelength 700nm (A ₇₀₀ ) The ratio (A ₄₅₀ /A ₇₀₀ ) of 2.5 or more has the advantage of being able to manufacture a polarizer.

Hereinafter, preferred examples are provided to help understanding of the present invention, but the following examples are merely illustrative of the present invention, and it is apparent to those skilled in the art that various changes and modifications are possible within the scope and technical thought scope of the present invention. It is also natural that such modifications and modifications fall within the scope of the appended claims. In the following examples and comparative examples, "%" and "part" indicating the content are on a weight basis unless otherwise specified.

Example And Comparative example : Polarizer Produce

Example One

100 cm horizontally and vertically, 45 µm thick, and a clear unstretched polyvinyl alcohol film (VF-PE#4500, average polymerization degree 2400, KURARAY) having a saponification degree of 99.9% or more is immersed in water (deionized water) at 30° C. for 60 seconds. After swelling, 1.0 mmol/L of iodine, 1.25% by weight of potassium iodide, and 0.3% by weight of boric acid were immersed in a 30°C dyeing aqueous solution for 2 minutes and stained. At this time, in the swelling and dyeing step, stretching was performed at a stretching ratio of 1.9 times and 1.4 times, respectively, and the stretching ratio to the dyeing tank was stretched to be 2.66 times.

Subsequently, the mixture was immersed in a 53°C crosslinking aqueous solution containing 9% by weight of potassium iodide and 4% by weight of boric acid for 60 seconds to crosslink and stretched at a draw ratio of 2.15 times. Subsequently, in the complementary color step, it was immersed in an aqueous solution for complementary color at 40°C containing 13% by weight of potassium iodide and 4% by weight of boric acid for 10 seconds. At this time, the total cumulative draw ratio of swelling, dyeing and crosslinking, and complementary colors was set to be 5.72 times.

Thereafter, washing was performed for 2 seconds in a pure aqueous solution at 11° C. to remove foreign matter from the surface of the polarizer. After the water washing was completed, the polarizer was stretched 0.97 times while performing drying at 90° C. for 2 minutes to prepare a polarizer.

Example 2 to 3 and Comparative example 1 to 3

A polarizer was manufactured in the same configuration and method as in Example 1, except that the conditions described in Table 1 were changed.

division	Complementary steps	Pre-heat treatment	Washing step	dry
	Potassium iodide (% by weight)	Infrared radiation per unit volume (J/cm 3 )	Temperature (℃)	Stretch ratio (ship)
Example 2	15.0	0	11	0.96
Example 3	15.0	0	11	0.98
Comparative Example 1	9.0	0	18	0.96
Comparative Example 2	9.0	0	18	0.96
Comparative Example 3	11.0	0	11	0.96

Example 4 to 7

After the complementary color step was completed, pre-heat treatment was performed using the conditions in Table 2 below, and after completion of the pre-heat treatment, water was washed for 2 seconds in a pure aqueous solution of 11° C. to remove foreign substances on the surface of the polarizer, and then the polarizer was removed at 90° C. While performing drying for 2 minutes, stretching was performed at 0.98 times to prepare a polarizer.

The pre-heat treatment was performed using infrared rays. At this time, a infrared ray heater made of Twin Tube transparent quartz glass from Heraeus was used as a far infrared (IR) heater, and a Fast Response Medium wave (1.5 um lamp) wavelength was used.

division	Complementary steps	Pre-heat treatment	Washing step	dry
	Potassium iodide (% by weight)	Infrared radiation per unit volume (J/cm 3 )	Temperature (℃)	Stretch ratio (ship)
Example 4	15.0	1260	11	0.98
Example 5	15.0	1570	11	0.98
Example 6	15.0	1890	11	0.98
Example 7	15.0	2200	11	0.98

Experimental Example 1: Orthogonal color b measurement

After cutting the polarizers prepared in Examples and Comparative Examples to a size of 4 cm × 4 cm, measuring the orthogonal color b value using an ultraviolet visible light spectrometer (V-7100, JASC), and the results are shown in Table 3 below. It was described.

Experimental Example 2: Polarizer Absorbance ratio (A700/A450) Measurement

The absorbers obtained by measuring the absorbance (A ₄₅₀ ) at a wavelength of ₄₅₀ nm and the absorbance at a wavelength of 700 nm (A ₇₀₀ ) using an ultraviolet visible light spectrometer (V-7100, JASC) were used for the polarizers obtained in Examples and Comparative Examples. Ratio (A ₄₅₀ /A ₇₀₀ ) was obtained, and the results are shown in Table 3 below.

Experimental Example 3: Polarizer Polarization characteristic measurement

The polarizer obtained in the above Examples and Comparative Examples was measured using a UV-visible spectrometer (V-7100, JASC) to measure the luminous intensity corrected single transmittance (Ty) and the luminous intensity corrected polarization (Py), and the results are as follows. It is listed in Table 3.

division	Orthogonal color b	A 450 /A 700	Ty 450	Py 450
Example 1	0.840	2.5	41.1	99.949
Example 2	1.200	2.6	41.2	99.945
Example 3	0.820	2.7	41.2	99.968
Example 4	1.570	3.0	41.2	99.970
Example 5	2.190	3.5	41.2	99.973
Example 6	3.250	4.3	41.2	99.977
Example 7	4.360	5.1	41.1	99.979
Comparative Example 1	-0.140	1.4	38.7	99.997
Comparative Example 2	-1.820	1.7	41.2	99.945
Comparative Example 3	0.560	2.4	41.1	99.943

Referring to Table 3, it was confirmed that Examples 1 to 7 satisfy all of the polarization characteristics required by the present invention.

Experimental Example 4: Polarizer By wavelength Transmittance measurement

The polarizers obtained in the above Examples and Comparative Examples were measured for orthogonal transmittance for each wavelength by using an ultraviolet visible light spectrometer (V-7100, JASC), and the results are graphed in FIGS. 1 and 2.

1 and 2, in Examples 1 to 7 satisfying all of the polarization characteristics proposed in the present invention, it was confirmed that the transmittance of the blue light (blue light source) in the wavelength range of about 430 to 480 nm was reduced. Together, it was confirmed that the transmittance of the long wavelength of about 630 nm or higher was maintained high.

Claims (9)

1. The orthogonal color b value is -1.0 or more,

   The ratio (A ₄₅₀ / A ₇₀₀₎ of the absorbance (A ₄₅₀₎ and absorbance at wavelength of 700nm (A ₇₀₀₎ at a wavelength of 450nm polarizer, characterized in that not less than 2.5.
2. According to claim 1,

   The polarizer is a polarizer characterized in that the luminous intensity correction single transmittance (Ty) at a wavelength of 450 nm is at least 41%, and the luminous intensity correction polarization (Py) is at least 99.945%.
3. According to claim 1,

   The polarizer is characterized in that the orthogonal color b value is -1.0 to 10.
4. A polarizing plate comprising the polarizers of claim 1.
5. An image display device comprising the polarizing plate of claim 4.
6. Swelling step, dyeing step, stretching step, crosslinking step, complementary color step, washing step and drying step,

   The complementary color step is performed using a complementary solution containing a boric acid compound and potassium iodide, and the polarizer of claim 1, wherein the potassium iodide is included in an amount of 12 to 15% by weight based on 100% by weight of the complementary solution. Method of manufacturing.
7. The method of claim 6,

   The manufacturing method of the polarizer further comprises a pre-heat treatment step.
8. The method of claim 6,

   In the washing step, the temperature of the washing bath is 4°C or more and less than 18°C.
9. The method of claim 7,

   In the pre-heat treatment step, a method of manufacturing a polarizer, wherein the amount of infrared radiation per unit volume of the film for forming a polarizer is 1000 to 3000 J/cm ³ .

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