TW201634260A - Polarizing plate, liquid crystal panel and liquid crystal display device - Google Patents

Abstract

The present invention provides a polarizing plate, a liquid crystal display panel and a liquid crystal display device using the same. The polarizing plate comprises an absorptive polarizer, and a blue light-transmission restraining layer disposed on the polarizer which restrains transmission of blue light at wavelengths of 380 to 500 nm. The blue light-transmission restraining layer absorbs the blue light and thereby restrains transmission of blue light.

Description

Polarizer, liquid crystal panel and liquid crystal display device

The present invention relates to a polarizing plate having a blue light cutoff function, and a liquid crystal panel and a liquid crystal display device using the polarizing plate.

With the advancement of IT technology, the digital machine has penetrated into the life, greatly increasing the time of viewing the screen of a liquid crystal display device such as a personal computer or a mobile phone, a smart phone, a portable game device, etc., and thus some people accuse the LED liquid crystal display device from issuing The blue light in the light will have an adverse effect on the eyes.

In order to reduce the incidence of blue light on the naked eye, it has been conventionally known to use glasses having a blue cut-off function or a technique of externally attaching a film having a blue cut-off function to a screen of a liquid crystal display device (examples of the latter, for example, Japanese Patent Laid-Open Publication No. 2014-144632) ].

SUMMARY OF THE INVENTION An object of the present invention is to realize a liquid crystal display device which can reduce blue light from entering an eye even if it does not wear special glasses or does not have an external film on the screen.

The present invention provides a polarizing plate and a liquid crystal represented by the following Panel and liquid crystal display device.

[1] A polarizing plate comprising an absorption type polarizer, and a blue light transmission suppressing layer disposed on the polarizer to suppress blue light transmission in a wavelength region of 380 to 500 nm.

[2] The polarizing plate according to [1], wherein the blue light transmission suppressing layer is prevented from being transmitted by absorbing the aforementioned blue light.

[3] The polarizing plate according to [1], wherein the blue light transmission suppressing layer has an average transmittance of 80% or less in a wavelength region of 380 to 500 nm.

[4] The polarizing plate according to any one of [1] to [3] further comprising a thermoplastic resin film disposed between the blue light transmission suppressing layer and the polarizing plate.

[5] The polarizing plate according to [4], wherein the thermoplastic resin film is selected from the group consisting of a cyclic polyolefin resin, a polycarbonate resin, a cellulose ester resin, a polyester resin, and (methyl) A resin composed of a group of acrylic resins.

[6] The polarizing plate according to any one of [1] to [5] wherein the blue light transmission suppressing layer, the polarizing plate and the adhesive layer are sequentially included.

[7] A liquid crystal panel comprising a liquid crystal cell and the polarizing plate according to [6], The polarizing plate is laminated on the liquid crystal cell via the adhesive layer.

[8] A liquid crystal display device comprising a backlight and [7] The liquid crystal panel, The polarizing plate is disposed between the liquid crystal cell and the backlight.

According to the present invention, it is possible to provide a liquid crystal display device which has reduced the amount of blue light emitted from the screen. If the liquid crystal display device is used, the blue light can be reduced into the eye without wearing special glasses or an external film on the screen.

1, 2, 3‧ ‧ polarizing plates

5‧‧‧ polarizer

10‧‧‧1st thermoplastic resin film

15‧‧‧1st adhesive layer

20‧‧‧2nd thermoplastic resin film

25‧‧‧2nd adhesive layer

30‧‧‧Blue light transmission suppression layer

31‧‧‧Base film

35‧‧‧Blue light transmission suppression film

40‧‧‧1st adhesive layer

45‧‧‧2nd adhesive layer

60‧‧‧LCD panel

70‧‧‧ Backlight

80‧‧‧LCD

90‧‧‧ front polarizer

100‧‧‧Liquid crystal display device

Fig. 1 is a schematic cross-sectional view showing an example of a layer configuration of a polarizing plate of the present invention.

Fig. 2 is a schematic cross-sectional view showing another example of the layer configuration of the polarizing plate of the present invention.

Fig. 3 is a schematic cross-sectional view showing still another example of the layer configuration of the polarizing plate of the present invention.

Fig. 4 is a schematic cross-sectional view showing an example of a layer configuration of a liquid crystal panel and a liquid crystal display device of the present invention.

<Polarizing plate>

The polarizing plate of the present invention comprises an absorption type polarizer and a blue light transmission suppressing layer (blue light blocking layer) disposed thereon to suppress blue light transmission in a wavelength region of 380 to 500 nm, which has a blue light cutoff function. By arranging the polarizing plate and the liquid crystal panel including the polarizing plate on the LED liquid crystal display device, the amount of blue light in the wavelength region emitted from the screen of the liquid crystal display device can be reduced.

(1) Composition of polarizing plate

Referring to the drawings, examples of the layer configuration of the polarizing plate of the present invention are exemplified below.

Fig. 1 is a schematic cross-sectional view showing an example of a polarizing plate of the present invention. The polarizing plate 1 shown in Fig. 1 includes a polarizer 5, a first thermoplastic resin film 10 laminated on one surface of the polarizer 5 via the first adhesive layer 15, and laminated on the first thermoplastic resin film 10. The blue light transmission suppressing layer (blue light blocking layer) 30 on the outer surface, the second thermoplastic resin film 20 laminated on the other surface of the polarizer 5 via the second adhesive layer 25, and the second thermoplastic resin film laminated on the second thermoplastic resin film The first adhesive layer 40 on the outer surface of 20. The first adhesive layer 40 is used to bond the polarizing plate 1 to another optical member such as a liquid crystal cell. In this case, the blue light transmission suppressing layer 30 in the obtained liquid crystal panel forms one of the liquid crystal panels. The most surface. The same applies to the polarizing plate 2 shown in Fig. 2 described below and the blue light transmitting suppressing layer 30 of the polarizing plate 3 shown in Fig. 3.

As will be described later in detail, the first and second thermoplastic resin films 10 and 20 may be protective films for protecting the polarizing plate 5 and the like. The polarizing plate 1 is an example in which the blue light transmission suppressing layer 30 is directly formed on the outer surface of such a thermoplastic resin film.

Fig. 2 is a schematic cross-sectional view showing another example of the polarizing plate of the present invention. In the polarizing plate 2 shown in Fig. 2, a blue light transmission suppressing film (blue light blocking film) 35 having a blue light transmitting and suppressing layer 30 is used on one surface of the base film 31, and this layer is laminated via the second adhesive layer 45. The polarizing light shown in Fig. 1 is provided on the outer surface of the first thermoplastic resin film 10 The plate 1 is composed of the same layer. Therefore, by using the blue light transmission suppressing film 35, the adhesive layer (or the adhesive layer or the like) is bonded to the thermoplastic resin film of the polarizing plate, and the blue light blocking function can be imparted to the polarizing plate.

Fig. 3 is a schematic cross-sectional view showing still another example of the polarizing plate of the present invention. The polarizing plate 3 shown in FIG. 3 has the same layer configuration as the polarizing plate 2 shown in FIG. 2 except that the first adhesive layer 15 and the first thermoplastic resin film 10 are not included. Therefore, the blue light transmission suppressing film 35 may be laminated on the polarizing plate 5 via the second adhesive layer 45. The second adhesive layer 45 may be replaced with an adhesive layer (in this case, the layer configuration of Fig. 3 is also considered to be the same as the layer configuration of Fig. 1).

The polarizing plate of the present invention may be, for example, the following constituents, without being limited to the examples of Figs. 1 to 3 .

[a] arranging the blue light transmission suppressing layer 30 on one side with reference to the polarizing plate 5, and also arranging the blue light transmission suppressing layer 30 or the like on the other side, so that the polarizing plate can include two or more blue light transmitting and suppressing layers 30 or The blue light transmission suppressing film 35. Thereby, the blue light cutoff function can be improved.

[b] The blue light transmission suppressing layer 30 or the blue light transmitting suppressing film 35 is not necessarily disposed on the outermost surface of the polarizing plate. For example, an optical functional film (or layer), a protective film (also referred to as "surface protective film"), an adhesive layer, or the like may be provided on the outer surface layer of the blue light transmission suppressing layer 30. Referring to FIGS. 2 and 3, the order of lamination of the blue light transmission suppressing layer 30 and the base film 31 may be reversed. The first adhesive layer 40 for bonding the polarizing plate to the liquid crystal cell is disposed on the side of the blue light transmission suppressing layer 30 or the blue light transmitting suppressing film 35, and when the liquid crystal panel is formed, the blue light transmitting inhibiting layer 30 or the blue light transmitting suppressing film is not provided. 35 is the outermost surface, and it can also be arranged on the cell side of the liquid crystal.

[c] The first thermoplastic resin film 10 and/or the second thermoplastic resin film 20 may be omitted. The blue light transmission suppressing layer 30 is directly deposited on the polarizer 5 by omitting the thermoplastic resin film, or the blue light transmitting suppressing film 35 is laminated on the polarizer 5 via an adhesive layer or an adhesive (the third example is the latter). Meanwhile, referring to FIGS. 1 to 3, the first adhesive layer 40 may be directly deposited on the polarizer 5 by omitting the second adhesive layer 25 and the second thermoplastic resin film 20. However, in terms of durability of the polarizing plate or the protective polarizer, the polarizing plate is preferably provided with a thermoplastic resin film on at least one surface of the polarizing plate 5. The thermoplastic resin film may be the base film 31 of the blue light transmission suppressing film 35.

[d] The polarizing plate may include other components than the components shown in FIGS. 1 to 3 . Specific examples of other constituent elements are an optical functional film (or layer), a protective film, and a separation film (also referred to as "release film") laminated on the outer surface of the adhesive layer.

Here, by using the blue light transmission suppressing film 35, the adhesive layer (or the adhesive layer) is attached to the surface of the other film of the constituent elements of the polarizing plate, and the blue light transmitting suppressing layer 30 is introduced onto the polarizing plate. The form is preferable because the polarizing plate is easy to manufacture and the selection of the types of the other films described above is limited and can be widely selected.

(2) Polarizer

The polarizer 5 is an absorbing polarizer for linearly polarizing light from one direction of natural light and absorbing linear polarized light in the other direction, for example, a polyvinyl alcohol-based resin film is adsorbed and oriented as a dichroic dye. of The iodine iodine-based polarizer and the polyvinyl alcohol-based resin are adsorbed and oriented as a dichroic dye of a dichroic dye, and a dichroic dye coated with a lyotropic liquid crystal. Oriented, immobilized coated polarizer, and the like. Among them, a polarizing plate in which a polyvinyl alcohol-based resin film is adsorbed, or a dichroic dye such as a di- or dichroic dye is preferable, and a polarizing plate which adsorbs and orients iodine with a polyvinyl alcohol-based resin is more preferable.

The polyvinyl alcohol-based resin constituting the polarizer can be saponified using a polyvinyl acetate-based resin. The polyvinyl acetate-based resin may be a copolymer of vinyl acetate and another monomer copolymerizable, in addition to polyvinyl acetate of a homopolymer of vinyl acetate. Examples of other monomers copolymerizable with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl esters, unsaturated sulfonic acids, and (meth) acrylamides having an ammonium group.

The degree of saponification of the polyvinyl alcohol-based resin is usually about 85 to 100 mol%, and preferably 98 mol% or more. The polyvinyl alcohol-based resin may be modified, and for example, an aldehyde-modified polyethylene formaldehyde or a polyvinyl acetal may be used. The average degree of polymerization of the polyvinyl alcohol-based resin is usually about 1,000 to 10,000, and preferably about 1,500 to 5,000. The average degree of polymerization of the polyvinyl alcohol-based resin can be determined in accordance with JIS K 6726.

A film formed of such a polyvinyl alcohol-based resin can be used as a film of the polarizer 5. The method of forming a film of a polyvinyl alcohol-based resin is not particularly limited, and a known method can be employed. The thickness of the polyvinyl alcohol-based germplasm film is, for example, 150 μm or less, and preferably 100 μm or less (for example, 50 μm or less).

The polarizer 5 can be manufactured by a method comprising the following steps: a step of uniaxially stretching a polyvinyl alcohol resin film; a step of adsorbing a polyvinyl alcohol resin film with a dichroic dye to adsorb a dichroic dye; and a polyvinyl alcohol adsorbing a dichroic dye The step of treating the resin film with an aqueous solution of boric acid (crosslinking treatment); and the step of washing with water after treatment with an aqueous solution of boric acid.

The uniaxial stretching of the polyvinyl alcohol-based resin film can be carried out before, after, or after dyeing of the dichroic dye. This uniaxial extension can be carried out prior to boric acid treatment or boric acid treatment when uniaxially extending after dyeing. At the same time, uniaxial stretching can also be performed in several stages of such processing.

When uniaxially extending, uniaxial stretching can be performed between rolls of different peripheral speeds, or uniaxial stretching can be performed using a heat roll. Meanwhile, the uniaxial stretching may be a dry stretching which is extended in the atmosphere, or may be a wet stretching in which a state in which the polyvinyl alcohol-based resin film is expanded by using a solvent or water. The stretching ratio is usually about 3 to 8 times.

A method of dyeing a polyvinyl alcohol-based resin film with a dichroic dye may be, for example, a method of immersing the film in an aqueous solution containing a dichroic dye. As the dichroic dye system, iodine or a dichroic organic dye can be used. Further, the polyvinyl alcohol-based resin film is preferably applied to an immersion treatment in water before the dyeing treatment.

By the dyeing treatment of iodine, a method of immersing a polyvinyl alcohol-based resin film in an aqueous solution containing iodine and potassium iodide can be usually employed. The iodine content in the aqueous solution may be from about 0.01 to about 1 part by weight per 100 parts by weight of water. The content of potassium iodide may be from about 0.5 to 20 parts by weight per 100 parts by weight of water. At the same time, the temperature of the aqueous solution may be about 20 to 40 °C. On the other hand, a dyeing treatment of a dichroic organic dye is usually carried out by immersing a polyhydric alcohol resin film in an aqueous solution containing a dichroic organic dye. The aqueous solution containing a dichroic organic dye may contain an inorganic salt such as sodium sulfate as a dyeing auxiliary. The content of the dichroic organic dye in the aqueous solution may be about 1 × 10 ^-4 to 10 parts by weight per 100 parts by weight of water. The temperature of this aqueous solution may be about 20 to 80 °C.

The boric acid treatment after dyeing the dichroic dye can be usually carried out by immersing the dyed polyvinyl alcohol-based resin film in an aqueous solution containing boric acid. When iodine is used as the dichroic dye, the aqueous solution containing boric acid is preferably one containing potassium iodide. The amount of boric acid in the aqueous solution containing boric acid may be from about 2 to 15 parts by weight per 100 parts by weight of water. The amount of potassium iodide in the aqueous solution may be from about 0.1 to 20 parts by weight per 100 parts by weight of water. The temperature of the aqueous solution may be 50 ° C or higher, for example, 50 to 85 ° C.

The polylactic acid-based resin film after the boric acid treatment is usually water-washable. The water washing treatment is carried out, for example, by immersing a boric acid-treated polyethylenary resin film in water. The temperature of the water in the water washing treatment is usually about 5 to 40 °C. After washing with water, drying treatment is carried out to obtain a polarizing plate 5. The drying treatment can be carried out using a hot air dryer or a far infrared heater.

In the meantime, the method of the method of manufacturing the polarizer 5 is exemplified by the method described in JP-A-2000-338329 or JP-A-2012-159778. In this method, a solution containing a polyvinyl alcohol-based resin is applied to the surface of the base film to provide a resin layer. Thereafter, the laminated film including the base film and the resin layer is stretched, followed by dyeing treatment, crosslinking treatment, or the like to form a polarizer layer from the resin layer. The polarizing laminated film including the base film and the polarizer layer is bonded to a thermoplastic resin film such as a protective film on the polarizer layer, and then the base film is peeled off and removed, and the polarizing film 5 can be formed on one surface. A polarizing plate of a thermoplastic resin film. When a thermoplastic resin film is bonded to the surface of the polarizer exposed by peeling off the base film, a polarizing plate having a thermoplastic resin film on both surfaces of the polarizer 5 can be obtained.

The thickness of the polarizer 5 can be 40 μm or less, and preferably 30 μm or less (for example, 20 μm or less and 15 μm or less, and 10 μm or less). The thin film polarizer 5 can be more easily produced by the method described in JP-A-2000-338329 or JP-A-2012-159778, and the thickness of the polarizer 5 can be more easily made, for example, 20 μm or less and 15 μm. Hereinafter, it is 10 μm or less. The thickness of the polarizer 5 is usually 2 μm or more. When the thickness of the polarizer 5 is made small, it is advantageous for the polarizing plate and the thickness of the liquid crystal display device.

(3) Blue light transmission suppression layer

The blue light transmission suppressing layer 30 is a layer that suppresses the transmission of blue light in a wavelength region of 380 to 500 nm, and preferably suppresses the layer of blue light transmission in the entire wavelength region. In order to impart a good blue light cutoff function to the polarizing plate, the blue light transmission suppressing layer 30 preferably has an average transmittance of 80% or less in a wavelength region of 380 to 500 nm, and more preferably 75% or less. The average transmittance of the blue light transmission suppressing layer 30 in the wavelength region of 380 to 500 nm can be measured by a spectrophotometer for the transmittance in each wavelength (grain 5 nm). These averages are obtained in the wavelength region up to 500 nm.

As shown in FIGS. 2 and 3, the blue light transmission suppressing layer 30 can also be incorporated into the polarizing plate in the form of the blue light transmission suppressing layer 35 having the blue light transmitting and suppressing layer 30 on one surface of the base film 31. However, the blue light transmission suppressing layer 30 does not have to be laminated on the surface of the base film 31. For example, the blue light transmission suppressing layer 30 may be formed as an inner layer to form a three-layer structure film inside the base film 31, or The blue light transmission suppressing layer 30 may also be the substrate film 31 itself having a blue light cutoff function.

The base film 31 can be made of a thermoplastic resin having light transmissivity (preferably optically transparent), and specific examples thereof can be referred to the thermoplastic resin film described later. The base film 31 is a resin selected from the group consisting of a cyclic polyolefin resin, a polycarbonate resin, a cellulose ester resin, a polyester resin, and a (meth)acrylic resin. The constituents are better. In the present specification, "(meth)acrylic group" means at least one selected from the group consisting of an acryl group and a methacryl group. It is also the same when it is called "(meth) acrylate".

The thickness of the blue light transmission suppressing layer 30 is, for example, 0.1 to 100 μm, and the thickness of the blue light transmission suppressing film 35 composed of the blue light transmission suppressing layer 30 and the base film 31 is, for example, 5 to 300 μm. As the blue light transmission suppressing layer 30 and the blue light transmission suppressing film 35, a conventionally known constituent can be used, and a commercially available product can also be used.

The blue light transmission suppressing layer 30 and the blue light transmitting suppressing film 35 which suppress the blue light transmission are roughly classified into a blue light transmitting person (absorption type) by suppressing the blue light and a blue light transmitting light (reflective type) by reflecting the blue light. In the present invention, an absorption type is particularly suitable. This is due to the reflection type The external light reflection into the blue light transmission suppressing layer 30 or the blue light transmission suppressing film 35 produces a color on the hue when the display screen is viewed. As long as it is an absorption type, such a problem does not occur, and good visibility is obtained. Meanwhile, in the case of the reflective type, when the liquid crystal panel is constructed by the polarizing plate and the liquid crystal cell, the blue light transmission suppressing layer 30 or the blue light transmitting suppressing film 35 is disposed between the polarizing plate 5 and the liquid crystal cell, so that the blue light transmitting suppressing layer 30 or the blue light can be The transmission suppressing film 35 serves to eliminate the polarizing element.

(4) Thermoplastic resin film

Each of the first thermoplastic resin film 10 and the second thermoplastic resin film 20 may be a film containing a thermoplastic resin having light transmissivity (preferably, optical transparency), and includes, for example, a chain polyolefin resin (polyethylene resin, a polyolefin resin such as a polypropylene resin or a cyclic polyolefin resin (such as a decene-based resin); a cellulose ester resin such as triethyl fluorenyl cellulose or diethyl hydrazine cellulose; a polyester resin of ethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate; a polycarbonate resin; a (meth)acrylic resin; or a mixture of such resins a film of a copolymer or the like. The first thermoplastic resin film 10 and the second thermoplastic resin film 20 are each selected from the group consisting of a cyclic polyolefin resin, a polycarbonate resin, a cellulose ester resin, a polyester resin, and a (meth) group. It is preferable that the resin in the group of the acrylic resin is formed.

Each of the first thermoplastic resin film 10 and the second thermoplastic resin film 20 may be either a film that is not stretched or a film that is uniaxially stretched or biaxially stretched. The two-axis extension may be a two-axis extension extending simultaneously in two extending directions, or may be extended in a set direction and then in another direction The successive two-axis extension of the extension. The first thermoplastic resin film 10 and/or the second thermoplastic resin film 20 may be a protective film that functions as a protective polarizing film 5, or may be a protective film having an optical function such as a retardation film. The retardation film is an optical functional film used for the purpose of compensating for a phase difference caused by a liquid crystal cell. For example, a retardation film having an arbitrary retardation value can be imparted by stretching a film containing the thermoplastic resin (uniaxial stretching or biaxial stretching or the like) or forming a liquid crystal layer or the like on the thermoplastic resin film.

The cyclic polyolefin-based resin is a general term for a resin containing a cyclic olefin represented by a norbornene or tetracyclododecene (also known as dimethanooctahydronaphthalene) or a derivative thereof. . Specific examples of the cyclic polyolefin-based resin include a ring-opened (co)polymer of a cyclic olefin, a hydrogenated product thereof, an addition polymer of a cyclic olefin, a chain olefin, and a chain such as ethylene or propylene. A copolymer of an olefin or an aromatic compound having a vinyl group, and a modified (co)polymer modified with the unsaturated carboxylic acid or a derivative thereof. Among them, a norbornene-based resin using a norbornene-based monomer such as a norbornene or a polycyclic norbornene monomer as a cyclic olefin is suitable.

The polycarbonate resin is a polyester formed of carbonic acid and a diol or bisphenol. Among them, in terms of heat resistance, weather resistance, and acid resistance, it is preferred to use an aromatic polycarbonate having a diphenyl alkane in a molecular chain. The polycarbonate-based resin can be exemplified by, for example, 2,2-bis(4-hydroxyphenyl)propane (also known as bisphenol A), 2,2-bis(4-hydroxyphenyl)butane, 1,1- Bisphenol-derived polycarbonate of bis(4-hydroxyphenyl)cyclohexane, 1,1-bis(4-hydroxyphenyl)isobutane, 1,1-bis(4-hydroxyphenyl)ethane .

The cellulose ester-based resin is a resin obtained by esterifying at least a part of a hydroxyl group in cellulose, and may be a mixed ester partially acidified and the other portion is acidified. The cellulose ester-based resin is preferably an acetamino cellulose-based resin. Specific examples of the ethyl ketone-based cellulose resin include triethyl fluorenyl cellulose, diethyl hydrazine cellulose, cellulose acetate propionate, and cellulose acetate butyrate.

The polyester resin is a resin other than the above cellulose resin having an ester bond, and is usually a polycondensate comprising a polyvalent carboxylic acid or a derivative thereof and a polyhydric alcohol. Specific examples of the polyester resin include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polybutylene naphthalate, and polytrimethylene terephthalate. Ester, propylene naphthalate, dimethyl dimethyl terephthalate, cyclohexane dimethyl phthalate. Among them, polyethylene terephthalate is suitable for mechanical properties, solvent resistance, scratch resistance, cost, and the like. The polyethylene terephthalate refers to a resin composed of 80 mol% or more of repeating units of ethylene terephthalate, and may contain constituent units derived from other copolymerized components.

The other copolymerization component may, for example, be a dicarboxylic acid component or a diol component. Examples of the dicarboxylic acid component include isophthalic acid, 4,4'-dicarboxybiphenyl, 4,4'-dicarboxybenzophenone, bis(4-carboxyphenyl)ethane, adipic acid, Azelaic acid, sodium 5-sulfonate isophthalate, 1,4-dicarboxycyclohexane, and the like. Examples of the diol component include propylene glycol, butanediol, neopentyl glycol, diethylene glycol, cyclohexanediol, ethylene oxide adduct of bisphenol A, polyethylene glycol, polypropylene glycol, and polybutylene. Glycol and the like. The dicarboxylic acid component or the diol component may be used in combination of two or more kinds as needed. At the same time, it can also be combined with the above dicarboxylic acid component Alternatively, a hydroxy carboxylic acid such as p-hydroxybenzoate or p-β-hydroxyethoxybenzoate may be used in combination. As the other copolymerization component, a dicarboxylic acid component and/or a diol component having a guanamine bond, an amine ester bond, an ether bond, a carbonate bond or the like may be used in a small amount.

The (meth)acrylic resin may be a polymer having methacrylate as a main monomer (containing 50% by weight or more), and preferably a copolymer obtained by copolymerizing a small amount of other copolymerization components. The (meth)acrylic resin is preferably a copolymer of methyl methacrylate and methyl acrylate, and may be copolymerized with a third monofunctional monomer.

The third monofunctional monomer may, for example, be, for example, ethyl methacrylate, methacrylic acid n-, iso- or tert-butyl ester, cyclohexyl methacrylate, phenyl methacrylate, benzyl methacrylate a methacrylate other than methyl methacrylate of 2-ethylhexyl methacrylate or 2-hydroxyethyl methacrylate; such as ethyl acrylate, n-, iso- or tert-butyl acrylate , acrylate of cyclohexyl acrylate, phenyl acrylate, benzyl acrylate, 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate; such as methyl 2-(hydroxymethyl)acrylate, 2-(1) -Hydroxyethyl)methyl acrylate, ethyl 2-(hydroxymethyl)acrylate, hydroxyalkyl acrylate of 2-(hydroxymethyl)acrylic acid n-, iso- or tert-butyl ester; such as methacrylic acid Unsaturated acids of acrylic acid; halogenated styrenes such as chlorostyrene and bromostyrene; substituted styrenes such as ethylene toluene and α-methylstyrene; unsaturated nitriles such as acrylonitrile and methacrylonitrile An unsaturated anhydride such as maleic anhydride or citraconic anhydride; such as phenyl maleimide, Hexyl maleic unsaturated acyl imine (PEI) and the like. The third monofunctional monomer can be used alone One type may be used, or two or more types may be used in combination.

In the (meth)acrylic resin, the polyfunctional monomer can be further copolymerized. The polyfunctional monomer may, for example, be, for example, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, tetraethylene glycol II. (Meth)acrylic acid ester, non-ethylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate ethylene glycol or oligomer thereof Esterifier; the terminal hydroxyl groups of propylene glycol or its oligomers are (meth)acrylated; such as neopentyl glycol di(meth)acrylate, hexanediol di(meth)acrylate, dibutyl The hydroxyl group of the diol of the alcohol di(meth)acrylate is (meth)acrylated; the alkylene oxide of bisphenol A, bisphenol A, or both terminal hydroxyl groups of such halogen substituents By (meth) acrylated; polyols such as trimethylolpropane, neopentyl alcohol, (meth) acrylated, and such terminal hydroxyl groups, glycidyl (meth) acrylate An epoxy group ring-opening additive; a dibasic acid such as succinic acid, adipic acid, terephthalic acid, phthalic acid, a halogen substituent of such an acid, and an alkylene oxide addition of such an acid The like (meth) acrylate, glycidyl methacrylate epoxy ring-opening addition of persons; (meth) acrylic acid aryl esters; divinylbenzene such as an aromatic divinyl compound. Among them, ethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, and neopentyl glycol dimethacrylate are preferably used.

The (meth)acrylic resin may be modified by further reacting the functional groups of the copolymer. The reaction may, for example, be an intramolecular decopolymerization reaction of a methyl ester group of methyl (meth)acrylate with a hydroxyl group of methyl 2-(hydroxymethyl)acrylate, or a (meth)acrylic acid. A polymer chain internal dehydration condensation reaction of a carboxyl group and a hydroxyl group of methyl 2-(hydroxymethyl)acrylate.

The glass transition temperature of the (meth)acrylic resin is preferably from 80 to 160 °C. The glass transition temperature may depend on the polymerization ratio of the methacrylate monomer and the acrylate monomer, the carbon chain length of each ester group, and the kind of the functional group, and the polyfunctional monomer relative to the monomer. Controlled by the adjustment of the polymerization ratio.

At the same time, it is also effective to introduce a ring structure into the main chain of the polymer as a glass transition temperature for increasing the (meth)acrylic resin. The ring structure is preferably a heterocyclic structure such as a cyclic acid anhydride structure, a cyclic quinone imine structure, or a lactone structure. Specific examples thereof include a cyclic acid anhydride structure such as a glutaric anhydride structure or a succinic anhydride structure, a quinodiimine structure, a cyclic quinone imine structure such as a succinimide structure, and a lactone such as butyrolactone and valerolactone. Ring construction. The larger the content of the ring structure in the main chain, the higher the glass transition temperature of the (meth)acrylic resin. The cyclic acid anhydride structure and the cyclic quinone imine structure can be introduced by a method in which a monomer having a cyclic structure such as maleic anhydride or maleimide is copolymerized and introduced. A method of introducing a cyclic acid anhydride structure by dehydration and demethylation condensation reaction after polymerization, a method of introducing an amine group compound into a cyclic quinone imine structure, and the like. A resin (polymer) having a lactone ring structure, after modulating a polymer having a hydroxyl group and an ester group on a polymer chain, heating the hydroxyl group and the ester group in the obtained polymer, as needed, such as organic It is obtained by a method of cyclization condensation to form a lactone ring structure in the presence of a catalyst of a phosphorus compound.

(Meth)acrylic resin, which may also be added as needed Additives. Examples of the additive include a lubricant, an anti-caking agent, a thermal stabilizer, an antioxidant, an antistatic agent, a light stabilizer, a wash resistance improver, a surfactant, and the like. When a thermoplastic resin other than the (meth)acrylic resin is used as the thermoplastic resin constituting the thermoplastic resin film, such additives may be used.

The (meth)acrylic resin may contain acrylic rubber particles of a squeezing property improver in terms of the film forming property of the film, the film resistance, and the like. The acrylic rubber particles are particles in which an elastic polymer mainly composed of an acrylate is an essential component, and may be a single layer structure including only the elastic polymer, or a multilayer having one layer of the elastic polymer. Constructor. Examples of the elastic polymer include a crosslinked elastic copolymer in which an alkyl acrylate is used as a main component, and another vinyl monomer and a crosslinkable monomer copolymerizable therewith are copolymerized. The alkyl acrylate which is a main component of the elastic polymer may, for example, be an alkyl group such as methyl acrylate, ethyl acrylate, butyl acrylate or 2-ethylhexyl acrylate having a carbon number of from 1 to 8 and It is preferred to use an alkyl acrylate having an alkyl group having 4 or more carbon atoms. The other vinyl monomer copolymerizable with the alkyl acrylate may, for example, be a compound having one polymerizable carbon-carbon double bond in the molecule, and more specifically, a methacrylate such as methyl methacrylate. For example, an aromatic vinyl compound of styrene, a vinyl cyanide compound such as acrylonitrile, or the like. The crosslinkable monomer may, for example, be a crosslinkable compound having at least two polymerizable carbon-carbon double bonds in the molecule, and more specifically, ethylene glycol di(meth)acrylate or butyl A (meth) acrylate of a polyol of an alcohol di(meth) acrylate, an (meth) acrylate ester of allyl (meth) acrylate, divinyl benzene, or the like.

A laminate of a film formed of a (meth)acrylic resin containing no rubber particles and a film of a (meth)acrylic resin containing rubber particles may be used as a protective film. At the same time, a (meth)acrylic resin layer may be formed on one surface or both surfaces of the phase difference display layer containing a resin different from the (meth)acrylic resin, and a phase difference may be obtained to form a protective film.

The first thermoplastic resin film 10 and/or the second thermoplastic resin film 20 may contain an ultraviolet absorber. When a polarizing plate is used for a liquid crystal display device, a protective film containing an ultraviolet absorber is disposed on the viewing side of the liquid crystal cell, and the liquid crystal cell is prevented from being deteriorated by ultraviolet rays. Examples of the ultraviolet absorber include a salicylate-based compound, a benzophenone-based compound, a benzotriazole-based compound, a cyanoacrylate-based compound, and a nickel-salted salt-based compound.

The first thermoplastic resin film 10 and the second thermoplastic resin film 20 may be films made of the same thermoplastic resin or may be formed of thermoplastic resins different from each other. The first thermoplastic resin film 10 and the second thermoplastic resin film 20 may be the same or different in thickness, presence or absence of an additive, type, phase difference characteristics, and the like.

The first thermoplastic resin film 10 and/or the second thermoplastic resin film 20 may have, for example, a hard coat layer, an antiglare layer, an antireflection layer, a light diffusion layer, and an anti-reflection layer on the outer surface thereof (the surface on the reverse side of the polarizing plate 5). A surface treatment layer (coating layer) of an electrostatic layer, an antifouling layer, and a conductive layer.

The thickness of the first thermoplastic resin film 10 and the second thermoplastic resin film 20 is usually 5 to 200 μm, preferably 10 to 120 μm, and more preferably 10 to 85 μm. The thickness of the first thermoplastic resin film 10 and the second thermoplastic resin film 20 is reduced, which is advantageous for the polarizing plate and the liquid. The crystal display device is thinned.

(5) adhesive layer

The first and second thermoplastic resin films 10 and 20 can be bonded to the polarizer 5 via the first and second adhesive layers 15 and 25, respectively. At the same time, the blue light transmission suppressing layer 30, the blue light transmission suppressing film 35, the optical functional film, and the like may be laminated via the adhesive layer. An adhesive for forming the above-mentioned adhesive layer can be an aqueous adhesive, an active energy ray-curable adhesive or a thermosetting adhesive, and an aqueous adhesive or an active energy ray-curable adhesive is preferred.

The aqueous adhesive agent may, for example, be an adhesive containing a polyvinyl alcohol-based resin aqueous solution or an aqueous two-component amine ester-based emulsion adhesive. Among them, an aqueous adhesive containing an aqueous solution of a polyvinyl alcohol-based resin is used. In addition to the vinyl alcohol homopolymer obtained by saponifying polyvinyl acetate of a homopolymer of vinyl acetate, a polyvinyl alcohol-based resin may be copolymerized with vinyl acetate and other monomers copolymerizable therewith. A polyvinyl alcohol-based copolymer obtained by subjecting a substance to saponification, or a modified polyvinyl alcohol-based copolymer whose hydroxyl group is modified. The aqueous binder may contain a crosslinking agent such as an aldehyde compound (such as glyoxal), an epoxy compound, a melamine compound, a methylol compound, an isocyanate compound, an amine compound, or a polyvalent metal salt.

When an aqueous adhesive is used, it is preferred to carry out a drying step for removing water contained in the aqueous adhesive after bonding the polarizer 5 to the thermoplastic resin film. After the drying step, a curing step of curing, for example, at a temperature of 20 to 45 ° C may also be provided.

The active energy ray-curable adhesive refers to an adhesive which hardens under irradiation with an active energy ray such as ultraviolet rays or electron beams, and can be exemplified For example, a curable composition containing a polymerizable compound and a photopolymerization initiator, a curable composition containing a photoreactive resin, a curable composition containing a binder resin and a photoreactive crosslinking agent, and the like. It is preferred to use an ultraviolet curable adhesive. The polymerizable compound may, for example, be a photocurable epoxy monomer, a photocurable (meth)acrylic monomer, a photocurable amine ester monomer, or a photopolymerizable monomer. Bulk oligomer. The photopolymerization initiator may be one which contains an active species such as a neutral radical, an anionic radical, or a cationic radical by irradiation with an active energy ray. The active energy ray-curable adhesive containing a polymerizable compound and a photopolymerization initiator is a curable composition containing a photocurable epoxy-based monomer and a photocationic polymerization initiator, and contains photocurability (A) The curable composition of the acrylic monomer and the photoradical polymerization initiator, or a mixture of such curable compositions is preferred.

The photocurable epoxy-based monomer is preferably an alicyclic epoxy compound. The alicyclic epoxy compound refers to a compound having one or more structures in the molecule which form an oxirane ring together with a carbon atom of an alicyclic ring. The alicyclic epoxy compound may be used alone or in combination of two or more. The "structure in which an oxirane ring is formed together with a carbon atom of an alicyclic ring" means a group formed by taking out one or several hydrogen atoms from (CH ₂ ) _m in the structure shown below. In the following formula, m is an integer of 2 to 5.

Therefore, a compound in which a group in which one or several hydrogen atoms in (CH ₂ ) _m is removed is bonded to another chemical structure can be an alicyclic epoxy resin. One or several hydrogen atoms in (CH ₂ ) _m may be appropriately substituted with a linear alkyl group of a methyl group or an ethyl group. Among the alicyclic epoxy compounds, an alicyclic epoxy compound having an oxabicyclohexane ring (m=4 in the above formula) or an oxabicycloheptane ring (m=5 in the above formula) is used. , because it can show excellent adhesion. Specific examples of suitable alicyclic epoxy compounds are listed below.

A:

B:

C:

D:

E:

F:

G:

H:

I:

J:

K:

L:

M:

When the active energy ray-curable adhesive is used, after the polarizer 5 is bonded to the thermoplastic resin film, a drying step is performed as needed, and then a curing step of curing the active energy ray-curable adhesive by irradiation of the active energy ray is performed. Therefore, when an active energy ray-curable adhesive is used, the adhesive layer is a cured layer thereof. The light source of the active energy ray is not particularly limited, and is preferably an ultraviolet ray having a light-emitting distribution at a wavelength of 400 nm or less. 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, a black light lamp, a microwave excited mercury lamp, a metal halide lamp, or the like can be used.

When the polarizer 5 is bonded to the thermoplastic resin film, in order to improve the adhesion, saponification treatment, corona treatment, plasma treatment, or the like may be performed on any of the bonding surfaces. When the protective film is bonded to both surfaces of the polarizer 5, the adhesive for bonding the protective film may be the same type of adhesive or a different type of adhesive.

The thickness of the adhesive layer after hardening is usually 20 μm or less, preferably 10 μm or less, more preferably 5 μm or less, and particularly preferably 3 μm or less. When the thickness of the layer is too large, the reaction rate of the adhesive composition is lowered, and the heat and humidity resistance of the polarizing plate is deteriorated. The thickness of the subsequent layer is usually 0.01 μm or more, and preferably 0.1 μm or more.

(6) Adhesive layer

The polarizing plate of the present invention may include a first adhesive layer 40 or another adhesive layer for bonding the other optical member such as a liquid crystal cell (for bonding the blue light shown in FIGS. 2 and 3). The second adhesive layer 45 for the transmission suppression film 35 and the blue light transmission suppression layer 30 or the adhesive layer for bonding the optical functional film, etc.).

As the adhesive to be used in the above-mentioned adhesive layer, a base polymer such as a (meth)acrylic resin, a polyoxymethylene resin, a polyester resin, a polyurethane resin, or a polyether resin can be used. Among them, in terms of transparency, adhesion, reliability, weather resistance, heat resistance, reworkability, etc., it is preferred to use a (meth)acrylic adhesive. (methyl) propylene In the acid-based adhesive, an alkyl (meth)acrylate having an alkyl group having a carbon number of 20 or less such as a methyl group or an ethyl group or a normal-, an iso- or a tri-butyl group, and a (meth)acrylic acid are used. Or a (meth)acrylic monomer containing a functional group such as hydroxyethyl (meth)acrylate, preferably having a glass transition temperature of 25 ° C or less, and preferably having a weight average molecular weight of 100 ° C or less of 100 ° C or less The above (meth)acrylic resin is suitable as a base polymer.

The formation of the adhesive layer on the polarizing plate can be directly applied to the polarized light by, for example, dissolving or dispersing the adhesive composition in a 10 to 40% by weight solution in an organic solvent such as toluene or ethyl acetate. The adhesive layer is formed on the target surface of the sheet, or the adhesive layer is formed into a sheet shape on the separation film to which the release treatment has been applied, and the adhesive layer is transferred to the target surface of the polarizing plate. The thickness of the pressure-sensitive adhesive layer may be determined in accordance with the adhesion force or the like, but it is preferably in the range of about 1 to 50 μm, and preferably in the range of 2 to 40 μm.

The polarizing plate may contain the above separation membrane. The separation membrane may be a film containing a polyethylene resin such as polyethylene, a polypropylene resin such as polypropylene, or a polyester resin such as polyethylene terephthalate. Among them, a stretch film of polyethylene terephthalate is preferred.

In the adhesive layer, glass fibers, glass granules, resin granules, fillers containing metal powder or other inorganic powder, pigments, colorants, antioxidants, ultraviolet absorbers, antistatic agents, and the like may be blended as needed.

Examples of the antistatic agent include an ionic compound, conductive fine particles, and a conductive polymer, and an ionic compound is preferably used. The cationic component constituting the ionic compound may be an inorganic cation or an organic cation. However, in terms of compatibility with the (meth)acrylic resin, an organic cation is preferred. Examples of the organic cation include a pyridinium cation, an imidazolium cation, an ammonium cation, a phosphonium cation, and a phosphonium cation. On the other hand, the anion component constituting the ionic compound may be an inorganic anion or an organic anion, but it is preferable to provide an anion component having a fluorine atom in terms of imparting excellent antistatic properties to the ionic compound. The anion component of the fluorine atom may, for example, be a hexafluorophosphate anion [(PF ₆ ^- )], a bis(trifluoromethanesulfonyl)imide anion [(CF ₃ SO ₂ ) ₂ N ^- ], or a bis (fluorine) Sulfhydryl)imine anion [(FSO ₂ ) ₂ N ^- ] and the like.

(7) Optical functional film

The polarizing plate may be provided with an optical functional film other than the polarizing plate 5 to impart a desired optical function, and a suitable example thereof is a retardation film. As described above, the first thermoplastic resin film 10 and/or the second thermoplastic resin film 20 can also serve as a retardation film, and a retardation film other than the thermoplastic resin film can be laminated. In the latter case, the retardation film may be laminated on the outer surface of the first thermoplastic resin film 10 and/or the second thermoplastic resin film 20 via the adhesive layer or the adhesive layer.

Specific examples of the retardation film include a birefringent film composed of a stretch film of a translucent thermoplastic resin, a film of a disc-shaped liquid crystal or a nematic liquid crystal which is oriented and fixed, and the liquid crystal has been formed on the base film. Layer. The base film is usually a film containing a thermoplastic resin, and the thermoplastic resin is preferably a cellulose ester resin such as triethyl fluorenyl cellulose.

The thermoplastic resin forming the birefringent film can be used for the first And the second thermoplastic resin film 10, 20 described above. For example, when a cellulose ester-based resin is used as an example, a method of forming a film from a compound having a phase difference adjusting function from a cellulose ester-based resin, and a phase difference adjustment in coating the surface of the cellulose ester-based resin film A method of a functional compound, a birefringent film is obtained by a method of uniaxially or biaxially stretching a cellulose ester-based resin. As the thermoplastic resin forming the birefringent film, other thermoplastic resins such as a polyvinyl alcohol resin, a polystyrene resin, a polyarylate resin, or a polyamide resin may be used.

For the purpose of controlling optical characteristics such as wide bandwidth, two or more retardation films can be used in combination. Meanwhile, it is not limited to a film having optical anisotropy, and a zero retardation film which is substantially optically equivalent may be used as the retardation film. Zero retardation film, retardation value R _e means the plane and thickness direction retardation R _th same time as a film of 15nm to -15. The in-plane phase difference value R _e and the thickness direction phase difference value R _th are the values in the wavelength 590 nm.

The in-plane phase difference value R _e and the thickness direction phase difference value R _th are respectively defined as follows: R _e =(n _x -n _y )×d

R _th = [(n _x + n _y )/2 - n _z ] × d. Where n _x is the refractive index in the slow axis direction (x-axis direction) in the film plane, and n _y is the refractive index in the fast axis direction in the film plane (in the plane perpendicular to the y-axis direction of the x-axis), n _z It is the refractive index of the film thickness direction (perpendicular to the z-axis direction of the film surface), and d is the thickness of the film.

On the zero retardation film, the first and second thermoplastic resins can be used. For the thermoplastic resin described in the film 10, 20 or the birefringent film, for example, a polyolefin resin containing a cellulose ester resin such as a chain polyolefin resin and a cyclic polyolefin resin such as polyparaphenyl may be used. A resin film of a polyester resin of ethylene diformate. Among them, it is preferable to use a cellulose ester resin or a polyolefin resin in order to easily control the phase difference value and to easily obtain it.

Examples of other optical functional films (optical members) which may be contained in a polarizing plate include a concentrating plate, a brightness improving film, a light diffusing layer (light diffusing film), and the like. These films are usually provided when the polarizing plate is a polarizing plate disposed on the back side (backlight side) of the liquid crystal cell.

The concentrating plate is a user for the purpose of optical path control, etc., and may be a prism array sheet, a lens array sheet, a dot attached sheet, or the like.

The brightness improving film is used to improve the brightness in a liquid crystal display device using a polarizing plate. Specifically, a reflective polarizing separation sheet in which anisotropy is generated in reflectance, an oriented film in which a cholesteric liquid crystal polymer is oriented, or a directional liquid crystal thereof is designed by laminating a plurality of films having different refractive indices of different refractive indices. A layer of a circularly polarizing separator or the like supported on a substrate film.

The light diffusion layer is provided separately for forming the polarizing plate as a diffusion type optical member. The diffusing type polarizing plate is used in a liquid crystal display device which imparts light diffusibility and suppresses display defects such as moiré. The light diffusion layer can be formed by a known method.

(8) Protective film

The polarizing plate of the present invention may contain a protective film for temporarily protecting the surface. Protective film, for example, attached to polarized light on a liquid crystal cell or other optical member After the board, it is peeled off along with the adhesive layer it has. The protective film is composed of a substrate film and an adhesive layer laminated thereon. The adhesive layer is referred to above. Examples of the resin constituting the base film include a polyethylene resin such as polyethylene, a polypropylene resin such as polypropylene, and a polyester system such as polyethylene terephthalate or polyethylene naphthalate. A thermoplastic resin such as a resin or a polycarbonate resin. A polyester resin such as polyethylene terephthalate is preferred.

<LCD panel and liquid crystal display device>

Fig. 4 is a schematic cross-sectional view showing an example of a layer configuration of a liquid crystal panel and a liquid crystal display device of the present invention. The liquid crystal display device 100 shown in Fig. 4 includes a backlight 70 and a liquid crystal panel 60 disposed thereon. The liquid crystal panel 60 is an optical element having a structure in which a polarizing plate is laminated on both surfaces of a liquid crystal cell. In the example shown in Fig. 4, the liquid crystal cell 80 and the layered layer have a surface on the back side (backlight 70 side). The polarizing plate 2 (back side polarizing plate) of the blue light cutoff function shown in Fig. 2 is formed of a front side polarizing plate 90 laminated on the front side (observation side) of the liquid crystal cell 80. The polarizing plate 2 (back side polarizing plate) and the front side polarizing plate 90 may be laminated on the liquid crystal cell 80 via an adhesive layer, for example, the polarizing plate 2 is interposed between the first adhesive layer 40 and the first adhesive layer 40. It is attached to the liquid crystal cell 80.

Not limited to the example of Fig. 4, the polarizing plate having the blue light cutoff function of the present invention can be used for both the front side polarizing plate and the back side polarizing plate and the front side polarizing plate. However, when the blue light transmission suppressing layer 30 or the blue light transmitting suppressing film 35 is of a reflective type, it is due to the outermost surface (when the blue light transmitting suppressing layer 30 or the blue light transmitting suppressing film 35 is disposed on the outermost surface) or the interface (blue) When the light transmission suppressing layer 30 or the blue light transmission suppressing film 35 is disposed at a position other than the outermost surface, the coloring plate is prevented from being colored by reflection of external light, and the polarizing plate of the present invention is used as a user of the back side polarizing plate. good.

In the liquid crystal panel 60 and the liquid crystal display device 100, as shown in FIG. 4, the polarizing plate of the present invention can be used as either a back side polarizing plate or a front side polarizing plate, and the blue light transmission suppressing layer 30 or the blue light transmitting suppressing film 35 can be used. The liquid crystal cell is laminated on the opposite side of the liquid crystal cell 80 (that is, the blue light transmission suppressing layer 30 or the blue light transmission suppressing film 35 is not disposed between the polarizing plate 5 and the liquid crystal cell 80) with reference to the polarizing plate 5. 80 is better. Therefore, even when the blue light transmission suppressing layer 30 or the blue light transmission suppressing film 35 is of a reflective type, it is possible to prevent these from being the depolarized light elements.

In one of the preferred embodiments of the liquid crystal panel and the liquid crystal display device of the present invention, the polarizing plate of the present invention includes at least a back side polarizing plate, and the blue light transmission suppressing layer 30 or the blue light transmitting suppressing film 35 (all of which are preferably several) The film is bonded to the liquid crystal cell so as to be disposed on the opposite side of the liquid crystal cell 80 with reference to the polarizer 5.

The backlight 70 is not particularly limited as long as it can emit blue light in a wavelength region of 380 to 500 nm, and a typical example thereof is a backlight in which an LED (Light Emitting Diode) is used as a light source. The driving method of the liquid crystal cell 80 can be any conventionally known.

[Examples]

Hereinafter, the present invention will be more specifically described by showing examples and comparative examples, but the present invention is not limited to these examples. In the following examples and comparative examples, the wavelength of 380 to 500 nm of the blue cut film and the polarizing plate The average transmittance of the region, and the opacity-corrected single-transmission ratio Ty, the opacity-corrected polarization degree Py, the transmitted hue, and the reflected hue of the polarizing plate were measured as follows.

(average transmittance)

Using a spectrophotometer with an integrating sphere ("V7100" manufactured by JASCO Corporation, 2 degree viewing angle; C light source], the transmittance in each wavelength (score 5 nm) was measured to obtain a wavelength range of 380 to 500 nm. The average of these is set to the average transmittance. The results are shown in Table 1. The average transmittance of the blue cut film can be said to be substantially the same as the average transmittance of the blue light transmission suppressing layer which it has.

(Visual sensitivity correction monomer transmittance and visual sensitivity correction polarization)

The monomer transmittance and the degree of polarization are defined as follows: single transmittance (λ) = 0.5 × (Tp (λ) + Tc (λ))

The degree of polarization (λ) = 100 × (Tp (λ) - Tc (λ)) / (Tp (λ) + Tc (λ)). Tp(λ) is the transmittance (%) of the polarizing plate measured by the relationship between the linear polarized light of the incident wavelength λ nm and the parallel Nicols, Tc(λ), which is a linear polarized light with an incident wavelength of λ nm. Transmittance (%) of the polarizing plate measured in relation to the cross Nicol.

The sensibility correction unit transmittance Ty and the opacity correction polarization degree Py are the single transmittance (λ) and the polarization (λ) obtained for each wavelength by the 2 degree angle of view (C light source) of JIS Z 8701. For the sensibility correction, a spectrophotometer with an integrating sphere ("V7100" manufactured by JASCO Corporation, 2 degree viewing angle; C light source] was used. When measured, it is installed It is as if the incident light is incident on the side of the norbornene resin film. Meanwhile, Ty and Py were measured at a wavelength of 380 to 780 nm in a range of 5 nm.

(transmission hue)

In accordance with JIS Z 8701, a spectrophotometer with an integrating sphere ("V7100" manufactured by JASCO Corporation, 2 degree viewing angle; C light source] was used. The results are shown in Table 1.

(reflective hue)

In accordance with JIS Z 8701, a spectrophotometer with an integrating sphere ("UV-2450/MPC-2200" manufactured by Shimadzu Corporation) was used to measure absolute specular reflection; a C light source was used to measure a wavelength of 400 to 780 nm at a thickness of 5 nm. range. The results are shown in Table 1.

<Example 1>

(1) Production of absorption type polarizer

By dry stretching, a polyvinyl alcohol film having a thickness of 30 μm (average degree of polymerization of about 2,400, a degree of saponification of 99.9 mol% or more) was uniaxially stretched to about 4 times, and kept in a tensioned state, immersed at 40 ° C. After 40 seconds in pure water, the dyeing treatment was carried out by immersing in an aqueous solution of iodine/potassium iodide/water in a weight ratio of 0.052/5.7/100 at 28 ° C for 30 seconds. Then, it was immersed in an aqueous solution of potassium iodide/boric acid/water in a weight ratio of 11.0/6.2/100 at 70 ° C for 120 seconds. Next, after washing with pure water of 8 ° C for 15 seconds, it was dried at 60 ° C for 50 seconds while maintaining the tension at 300 N/m, followed by drying at 70 ° C for 20 seconds to obtain a directional iodine adsorbed in the polyvinyl alcohol film. An absorbing polarizer having a thickness of 12 μm.

(2) Production of polarizing plate

100 parts by weight of water, 3 parts by weight of carboxyl-modified polyvinyl alcohol (trade name "KL-318" obtained from Kuraray Co., Ltd.) was dissolved, and 1.5 parts by weight of water-soluble epoxy resin was added to the aqueous solution. A guanamine epoxy-based additive [Sumirez Resin 650 (30)" obtained from the Takaoka Chemical Industry Co., Ltd., an aqueous solution having a solid concentration of 30% by weight, was prepared as an aqueous binder. This aqueous adhesive was applied to one surface of the absorbing polarizer obtained in the above (1), and a triethylene sulfonated cellulose (TAC) film (Konica Minolta) having a thickness of 25 μm was laminated via a roll layer via a roll. The trade name "KC2UA" manufactured by Opt Co., Ltd. has no phase difference characteristic. The protective film is formed on the other surface, and the surface layer difference of 10 nm or less and thickness is bonded to the other surface via an adhesive layer containing the same aqueous adhesive. 23 μm of a decene-based resin film (trade name "ZEONOR" manufactured by Zeon Co., Ltd., Japan). While maintaining the tension at 280 N/m, the laminate was dried at 60 ° C for 220 seconds after bonding for 5 seconds, followed by drying treatment at 80 ° C for 125 seconds to obtain a visually sensible corrected monomer transmittance. A polarizing plate having a Ty of 42.3% and a visual sensitivity corrected polarization Py of 99.995%. Then, a sheet-like adhesive ("#7" manufactured by Lintec Co., Ltd.) having a thickness of 25 μm was bonded to the outer surface of the decene-based resin film to form a polarizing plate with an adhesive layer. Hereinafter, the polarizing plate with the adhesive layer is referred to as "polarizing plate C".

Next, on the outer surface of the TAC film in the polarizing plate C, a blue cut film A (trade name "LCD-140WBC" manufactured by Sanwa Supply Co., Ltd., absorption type) was bonded to obtain a blue light cut-off function. Polarizer. Hereinafter, the polarizing plate with the adhesive layer is referred to as "polarizing plate A".

<Example 2>

A polarizing plate having a blue light-off function was obtained in the same manner as in Example 1 except that the blue cut film B (trade name "EF-FLBL series" manufactured by ELECOM Co., Ltd., and the reflective type] was used instead of the blue cut film A. Hereinafter, the polarizing plate to which the adhesive layer is attached is referred to as "polarizing plate B".

<Comparative Example 1>

The polarizing plate C produced in Example 1 was used as it was.

1‧‧‧Polar plate

5‧‧‧ polarizer

10‧‧‧1st thermoplastic resin film

15‧‧‧1st adhesive layer

20‧‧‧2nd thermoplastic resin film

25‧‧‧1st adhesive layer

30‧‧‧Blue light transmission suppression layer

40‧‧‧1st adhesive layer

Claims (8)

A polarizing plate comprising an absorption type polarizer, and a blue light transmission suppressing layer disposed on the polarizer to suppress blue light transmission in a wavelength region of 380 to 500 nm. The polarizing plate according to claim 1, wherein the blue light transmission suppressing layer suppresses transmission of the blue light by absorbing the blue light. The polarizing plate according to claim 1, wherein the blue light transmission suppressing layer has an average transmittance of 80% or less in a wavelength region of 380 to 500 nm. The polarizing plate according to claim 1, further comprising a thermoplastic resin film disposed between the blue light transmission suppressing layer and the polarizing plate. The polarizing plate according to claim 4, wherein the thermoplastic resin film is selected from the group consisting of a cyclic polyolefin resin, a polycarbonate resin, a cellulose ester resin, a polyester resin, and (methyl) A resin composed of a group of acrylic resins. The polarizing plate according to any one of claims 1 to 5, which comprises the blue light transmission suppressing layer, the polarizer and the adhesive layer in this order. A liquid crystal panel comprising a liquid crystal cell and a polarizing plate according to claim 6, wherein the polarizing plate is laminated on the liquid crystal cell via the adhesive layer. A liquid crystal display device comprising a backlight and a seventh aspect as claimed in the patent application In the liquid crystal panel of the invention, the polarizing plate is disposed between the liquid crystal cell and the backlight.