KR102621277B1 - liquid crystal display - Google Patents

Abstract

The liquid crystal display device of the present invention has a liquid crystal cell, a liquid crystal panel having a first polarizing film disposed on a viewing side from the liquid crystal cell and a second polarizing film disposed on a back side of the liquid crystal cell, and a backlight unit, the liquid crystal The panel has a maximum absorption wavelength in the wavelength range of 570 to 610 nm, and the backlight unit has a peak intensity (Gp) of the emission spectrum in the wavelength range of 515 to 545 nm, and a peak intensity (Gp) of the emission spectrum in the wavelength range of 605 to 650 nm. (Rp), and the average value (Ave) of the Gp, the Rp, and the intensity of the emission spectrum in the wavelength range of 580 to 600 nm is expressed in the following formula (1)
Ave1≤0.3×{(Gp+Rp)/2} (1)
is satisfied. The liquid crystal display panel satisfies wide color gamut and can suppress decline in luminance.

Description

liquid crystal display

The present invention relates to liquid crystal display devices. The liquid crystal display device can be applied to various applications.

In a liquid crystal display device, it is essential to arrange polarizing elements on both sides of the liquid crystal cell due to its image formation method, and polarizing films are generally attached. When attaching the polarizing film to a liquid crystal cell, an adhesive is usually used. In addition, the adhesion between the polarizing film and the liquid crystal cell is usually in close contact with each material using an adhesive to reduce light loss. In such cases, a polarizing film with an adhesive layer previously formed as an adhesive layer on one side of the polarizing film is generally used, as it has the advantage of not requiring a drying process to fix the polarizing film. .

Recently, brightness and clarity (i.e., wide color gamut) are required for image display devices, and organic EL displays (OLEDs) are attracting attention, but wide color gamut is also required for liquid crystal display devices. For example, as a method of converting a liquid crystal display device into a wide color gamut, a polarizing film is laminated on one or both sides of the liquid crystal cell through an adhesive layer containing a pigment that exhibits the maximum absorption wavelength in a specific wavelength range (560 to 610 nm). It has been proposed to do so (Patent Documents 1 and 2).

Japanese Patent Publication No. 2011-039093 Japanese Patent Publication No. 2014-092611

In addition to being contained in the adhesive layer as described above, the pigment may also be contained in the film layer applied to the optical member. In this way, an optical functional layer containing a pigment can be formed by including the pigment in a resin layer such as a film layer or an adhesive layer. As in Patent Documents 1 and 2, a liquid crystal display device using a liquid crystal panel in which a polarizing film is bonded to a liquid crystal cell with an adhesive layer containing a pigment can be photochromatized by the pigment. However, since the optical function layer contains a pigment, the pigment in the optical function layer deteriorates over time from the viewpoint of moisture permeability of the resin layer that serves as the base of the optical function layer, and the optical function layer gradually fades. In particular, when the optical function layer is an adhesive layer containing a pigment, the brightness of the liquid crystal display device is reduced because members forming the liquid crystal panel, such as the adhesive layer, contain the pigment.

The purpose of the present invention is to provide a liquid crystal display device that satisfies wide color gamut and can suppress a decrease in luminance.

As a result of repeated studies to solve the above problems, the present inventors discovered the following liquid crystal display device and completed the present invention.

That is, the present invention relates to a liquid crystal display device having a liquid crystal cell, a liquid crystal panel having a first polarizing film disposed on a viewing side from the liquid crystal cell, and a second polarizing film disposed on a back side of the liquid crystal cell, and a backlight unit. ,

The liquid crystal panel has a maximum absorption wavelength in the wavelength range of 570 to 610 nm, and also

The backlight unit is,

It has a peak intensity (Gp) of the emission spectrum in the wavelength range of 515 to 545 nm,

It has a peak intensity (Rp) of the emission spectrum in the wavelength range of 605 to 650 nm, and also has

The Gp, the Rp, and the average value (Ave1) of the intensity of the emission spectrum in the wavelength range of 580 to 600 nm are expressed by the following formula (1)

Ave1≤0.3×{(Gp+Rp)/2} (1)

It relates to a liquid crystal display device characterized in that it satisfies the following.

In the liquid crystal display device, the liquid crystal panel has a first optical functional layer disposed on a viewing side of the liquid crystal cell, and a second optical functional layer disposed on a back side of the liquid crystal cell, the first optical functional layer and At least one of the second optical functional layers can be one that contains a pigment that has a maximum absorption wavelength in the wavelength range of 570 to 610 nm.

In the liquid crystal display device, it is preferable that the transmittance of the maximum absorption wavelength of at least one of the first optical functional layer and the second optical functional layer is 50% or less.

In the liquid crystal display device, it is preferable that at least the first optical function layer contains the dye.

In the liquid crystal display device, the dye may be a tetraazaporphyrin-based dye.

In the liquid crystal display device, it is preferable to contain 0.01 to 5 parts by weight of the dye relative to 100 parts by weight of the solid weight of the base material forming the resin layer of the optical function layer.

Furthermore, the present invention relates to a liquid crystal display device having a liquid crystal cell, a liquid crystal panel having a first polarizing film disposed on a viewing side from the liquid crystal cell, and a second polarizing film disposed on a back side of the liquid crystal cell, and a backlight unit. ,

The liquid crystal panel has a maximum absorption wavelength in the wavelength range of 470 to 510 nm, and also

The backlight unit is,

It has a peak intensity (Bp) of the emission spectrum in the wavelength range of 430 to 480 nm,

It has a peak intensity (Gp) of the emission spectrum in the wavelength range of 515 to 545 nm, and also has

The average value (Ave2) of the Bp, the Gp, and the intensity of the emission spectrum in the wavelength range of 480 to 500 nm is expressed by the following formula (2)

Ave2≤0.15×{(Bp+Gp)/2} (2)

It relates to a liquid crystal display device characterized in that it satisfies the following.

In the liquid crystal display device, the liquid crystal panel has a first optical functional layer disposed on a viewing side of the liquid crystal cell, and a second optical functional layer disposed on a back side of the liquid crystal cell, the first optical functional layer and At least one of the second optical functional layers can be one containing a pigment having a maximum absorption wavelength in the wavelength range of 470 to 510 nm.

In the liquid crystal display device, it is preferable that the transmittance of the maximum absorption wavelength of at least one of the first optical functional layer and the second optical functional layer is 50% or less.

In the liquid crystal display device, it is preferable that at least the first optical function layer contains the dye.

In the liquid crystal display device, at least one type selected from tetraazaporphyrin-based dyes and cyanine-based dyes can be used as the dye.

In the liquid crystal display device, it is preferable to contain 0.01 to 5 parts by weight of the dye relative to 100 parts by weight of the solid weight of the base material forming the resin layer of the optical function layer.

In the liquid crystal display device of the present invention, the liquid crystal panel has a maximum absorption wavelength in a predetermined wavelength range. In this way, by absorbing light of a part of the wavelength in the liquid crystal panel, the overall color of the liquid crystal display device can be adjusted, and vividness can be improved by photocolor gamut. In particular, pigments with maximum absorption wavelengths in the wavelength range of 470~510nm and 570~610nm are not suitable for color expression in wavelength ranges other than RGB (wavelength range 470~510nm and/or wavelength range 570~610nm). By absorbing unnecessary light emission, the unnecessary light emission can be suppressed, making it effective in photo color gamut.

Additionally, the liquid crystal display device of the present invention combines a backlight unit whose emission spectrum within the predetermined wavelength range is controlled according to the liquid crystal panel having the maximum absorption wavelength in the predetermined wavelength range. In other words, it was thought that the reason why a decrease in luminance was seen in a liquid crystal display device using a liquid crystal panel with a maximum absorption wavelength in a certain wavelength range was because wavelength ranges other than RGB (the part where colors are mixed) were absorbed by the liquid crystal panel. In the present invention, depending on the liquid crystal panel having the maximum absorption wavelength in a wavelength range other than RGB, each spectral width of RG or each spectral width of GB is narrow, and the emission spectrum intensity within the wavelength range between RG or between GB is small. By using a backlight unit, it is designed to reduce the overlap between the wavelength range in which the liquid crystal panel absorbs light and the wavelength range of the backlight's emission spectrum, suppressing a decrease in luminance.

1 is a cross-sectional view showing one embodiment of a liquid crystal display device of the present invention.
Figure 2 is a graph showing an example of the emission spectrum of the backlight unit of the present invention.

Embodiments of the liquid crystal display device of the present invention will be described below with reference to the drawings. 1 is a cross-sectional view showing one embodiment of a liquid crystal display device of the present invention. In Figure 1, a liquid crystal panel (PN) and a backlight unit (BL) are shown. The liquid crystal panel (PN) includes a liquid crystal cell (C), a first polarizing film (P1) disposed on a viewing side from the liquid crystal cell (C), and a backlight unit (BL) side from the liquid crystal cell (C). ) has a second polarizing film (P2) disposed thereon. In addition, the liquid crystal panel (PN) includes a first optical functional layer (A1) disposed on a viewing side from the liquid crystal cell (C), and a second optical functional layer (A2) disposed on a back side from the liquid crystal cell (C). ) can have. The arrangement relationship between the first optical function layer (A1) and the first polarizing film (P1) on the viewing side of the liquid crystal cell (C), and the second optical function on the back side of the liquid crystal cell (C) The arrangement relationship between the layer (A2) and the second polarizing film (P2) is not particularly limited. In Fig. 1, the liquid crystal panel (PN) includes a first optical functional layer (A1) and a first polarizing film (P1) arranged in order from the side of the liquid crystal cell (C) toward the viewing side, and the liquid crystal cell (C). It is exemplified that it has a 2nd optical function layer (A2) and a 2nd polarizing film (P2) arranged in order from the side toward the back side.

The liquid crystal panel of the present invention has a maximum absorption wavelength in the wavelength range of 570 to 610 nm or 470 to 510 nm.

The provision of the maximum absorption wavelength in the above wavelength range to the liquid crystal panel of the present invention can be adjusted by mixing a dye into at least one of the members forming the liquid crystal panel. As a member to which a dye is mixed, it can be mixed, for example, with the liquid crystal cell which forms a liquid crystal panel, a 1st polarizing film, a 2nd polarizing film, a 1st optical functional layer, and a 2nd optical functional layer. Additionally, the dye can be mixed into the liquid crystal cell by blending the dye into a color filter or the like. Additionally, the dye can be blended into the first polarizing film and the second polarizing film by blending the dye into the transparent protective film that forms the polarizing film, its surface layer (hard coat layer), adhesive layer, anchor layer, etc.

In the present invention, the mixing of the dye into the liquid crystal panel is carried out in at least one of the first optical function layer and the second optical function layer from the viewpoint of satisfying photochromatic gamut and suppressing a decrease in luminance. desirable. In particular, it is preferable that the pigment contains at least the first optical function layer.

<Optical functional layer>

The first and second optical functional layers of the present invention are not particularly limited as long as they are resin layers containing a pigment. Examples of the resin layer include a film layer and an adhesive layer. The first and second optical functional layers may have the same function or may be different. The first and second optical functional layers can be formed from a composition containing a base polymer and a pigment.

The first and second optical functional layers having the dye preferably have a transmittance of 50% or less from the viewpoint of color gamut expansion at the maximum absorption wavelength in the wavelength range of 570 to 610 nm or 470 to 510 nm, and 30%. It is more preferable that it is 20% or less, and it is more preferable that it is 20% or less.

<Pigment>

Various pigments can be used as the pigment contained in the optical functional layer. Examples of the pigment include various compounds such as tetraazaporphyrin-based, porphyrin-based, cyanine-based, squaraine-based, azo-based, pyromethene-based, squaryllium-based, xanthene-based, and oxonol-based. From the viewpoint of photochromatization, the above-mentioned dyes are preferably tetraazaporphyrin-based dyes, porphyrin-based dyes, cyanine-based dyes, squarylium-based dyes, and squaraine-based dyes, and particularly preferable are tetraazaporphyrin-based dyes and cyanine-based dyes. The above pigment is specifically disclosed in Japanese Patent Application Laid-Open No. 2011-116818, etc. Only one type of the above-mentioned pigment may be used, or two or more types may be used in combination.

The dye having a maximum absorption wavelength in the wavelength range of 570 to 610 nm or 470 to 510 nm is used. Additionally, the dye may be one that has a maximum absorption wavelength in the wavelength range of 570 to 610 nm and 470 to 510 nm. A dye having a maximum absorption wavelength in the above wavelength range can absorb light emission unnecessary for color expression and suppress the light emission, making it effective in photocolor gamut. As a dye having a maximum absorption wavelength in the above wavelength range, a tetraazaporphyrin-based dye can be suitably used. For example, dyes that exhibit a maximum absorption wavelength in the wavelength range of 570 to 610 nm include tetraazaporphyrin-based compounds (product names: PD-320, PD311) manufactured by Yamamoto Chemicals, Inc., and tetraazaporphyrin-based compounds manufactured by YAMADA CHEMICAL CO., LTD. Azaporphyrin-based compounds (brand name: FDG-007), etc. can be mentioned. In addition, the maximum absorption wavelength of the dye was measured using a spectrophotometer (V-570 manufactured by JASCO Corporation). Pigments that exhibit a maximum absorption wavelength in the wavelength range of 470 to 510 nm include tetraazaporphyrin-based compounds manufactured by Yamamoto Chemicals, Inc. (compounds described in Japanese Patent No. 5015644) and cyanine-based compounds manufactured by YAMADA CHEMICAL CO., LTD. (Product name: FDB-007).

The amount of the above dye can be set appropriately depending on the member to be applied, the absorption wavelength range of the dye, and the extinction coefficient, but it should be 0.01 to 5 parts by weight based on 100 parts by weight of the solid weight of the base material of the member (hereinafter, the same standard). It is preferable, and 0.05 to 3 parts by weight is preferable, and 0.1 to 1 part by weight is more preferable. When blending the above-mentioned pigment into the adhesive layer, the content of the pigment is preferably 0.01 to 5 parts by weight based on 100 parts by weight of the solid weight of the base polymer in the adhesive composition forming the adhesive layer. In particular, the above range is preferable when using a tetraazaporphyrin-based dye or cyanine-based dye.

Below, each member of the liquid crystal panel of the present invention is explained.

<Liquid crystal cell>

Liquid crystal cells of various modes can be used for the liquid crystal cell C (configuration of glass substrate/liquid crystal layer/glass substrate). The liquid crystal layer of the liquid crystal cell (C) may be a liquid crystal layer containing homogeneously oriented liquid crystal molecules in the absence of an electric field. It is preferable to use nematic liquid crystal as the liquid crystal molecule. For example, liquid crystal cells such as IPS type mode, TN mode, STN mode, VA mode, etc. can be used.

The liquid crystal cell C has a configuration in which the liquid crystal layer is sandwiched between two transparent substrates. It may take the form of a liquid crystal panel with touch sensing function inside or outside the liquid crystal cell. Additionally, a color filter substrate can be installed on the liquid crystal cell (transparent substrate on the viewing side). Examples of materials forming the transparent substrate include glass or polymer film.

<Adhesive layer>

Examples of the optical functional layer of the present invention include an adhesive layer containing a pigment, and the adhesive layer can be formed from an adhesive composition containing an adhesive base polymer and a pigment. There is no particular limitation on the type of the adhesive base polymer, but examples include rubber-based polymer, (meth)acrylic-based polymer, silicone-based polymer, urethane-based polymer, vinyl alkyl ether-based polymer, polyvinyl alcohol-based polymer, polyvinylpyrrolidone-based polymer, Various polymers such as polyacrylamide-based polymer and cellulose-based polymer can be mentioned.

The adhesive composition of the present invention contains an adhesive base polymer as a main component. The main component refers to the component with the highest content among the total solids contained in the adhesive composition, for example, it refers to a component that occupies more than 50% by weight of the total solids contained in the adhesive composition, and also refers to a component that occupies more than 70% by weight.

Among these adhesive base polymers, those that are excellent in optical transparency, exhibit appropriate wettability, cohesiveness, and adhesive properties, and are excellent in weather resistance, heat resistance, etc., are preferably used. As one that exhibits such characteristics, a (meth)acrylic polymer is preferably used. Hereinafter, an acrylic adhesive whose base polymer is a (meth)acrylic polymer containing alkyl (meth)acrylate as a monomer unit as a forming material for the adhesive layer will be described.

<(meth)acrylic polymer>

The (meth)acrylic polymer usually contains alkyl (meth)acrylate as a main component as a monomer unit. In addition, (meth)acrylate refers to acrylate and/or methacrylate, and (meth) in the present invention has the same meaning.

Examples of the alkyl (meth)acrylate constituting the main skeleton of the (meth)acrylic polymer include linear or branched alkyl groups having 1 to 18 carbon atoms. These can be used alone or in combination. It is preferable that the average carbon number of these alkyl groups is 3 to 9.

In addition, alkyl (meth)acrylates containing aromatic rings, such as phenoxyethyl (meth)acrylate and benzyl (meth)acrylate, can be used for reasons of adhesion characteristics, durability, adjustment of phase difference, adjustment of refractive index, etc. .

Among the (meth)acrylic polymers, one or more types of copolymerized monomers having a polymerizable functional group having an unsaturated double bond such as a (meth)acryloyl group or a vinyl group can be introduced by copolymerization for the purpose of improving adhesiveness or heat resistance. there is. Specific examples of such copolymerized monomers include, for example, 2-hydroxyethyl (meth)acrylic acid, 3-hydroxypropyl (meth)acrylic acid, 4-hydroxybutyl (meth)acrylic acid, and 6-hydroxy (meth)acrylic acid. Hydroxyl such as hexyl, 8-hydroxyoctyl (meth)acrylic acid, 10-hydroxydecyl (meth)acrylic acid, 12-hydroxylauryl (meth)acrylic acid, or (4-hydroxymethylcyclohexyl)-methylacrylate. Sil group-containing monomer; Carboxyl group-containing monomers such as (meth)acrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid, and crotonic acid; monomers containing acid anhydride groups such as maleic anhydride and itaconic acid anhydride; caprolactone adduct of acrylic acid; Contains sulfonic acid groups such as styrenesulfonic acid, allylsulfonic acid, 2-(meth)acrylamide-2-methylpropanesulfonic acid, (meth)acrylamidepropanesulfonic acid, sulfopropyl(meth)acrylate, and (meth)acryloyloxynaphthalenesulfonic acid. monomer; and phosphoric acid group-containing monomers such as 2-hydroxyethyl acryloyl phosphate.

In addition, (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N-butyl(meth)acrylamide, N-methylol(meth)acrylamide, N-methylolpropane(meth)acrylamide, etc. (N-substituted) amide-based monomer; (meth)acrylic acid alkylaminoalkyl monomers such as aminoethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, and t-butylaminoethyl (meth)acrylate; (meth)acrylic acid alkoxyalkyl monomers such as methoxyethyl (meth)acrylate and ethoxyethyl (meth)acrylate; N-(meth)acryloyloxymethylenesuccinimide or N-(meth)acryloyl-6-oxyhexamethylenesuccinimide, N-(meth)acryloyl-8-oxyoctamethylenesuccinimide, N -Succinimide monomers such as acryloylmorpholine; Maleimide monomers such as N-cyclohexylmaleimide, N-isopropylmaleimide, N-laurylmaleimide, and N-phenylmaleimide; N-methyl itaconimide, N-ethyl itaconimide, N-butyl itaconimide, N-octyl itaconimide, N-2-ethylhexyl itaconimide, N-cyclohexyl itaconimide Itaconimide-based monomers such as mead and N-lauryl itaconimide can also be cited as examples of monomers for modification purposes.

In addition, as modified monomers, vinyl acetate, vinyl propionate, N-vinylpyrrolidone, methylvinylpyrrolidone, vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine, vinylpyrazine, vinylpyrrole, vinylimidazole, Vinyl monomers such as vinyloxazole, vinylmorpholine, N-vinylcarboxylic acid amides, styrene, α-methylstyrene, and N-vinylcaprolactam; Cyanoacrylate monomers such as acrylonitrile and methacrylonitrile; Acrylic monomers containing epoxy groups such as glycidyl (meth)acrylate; Glycol-based acrylic ester monomers such as polyethylene glycol (meth)acrylate, polypropylene glycol (meth)acrylate, methoxyethylene glycol (meth)acrylate, and methoxypolypropylene glycol (meth)acrylate; Acrylic acid ester monomers such as tetrahydrofurfuryl (meth)acrylate, fluorine (meth)acrylate, silicone (meth)acrylate, and 2-methoxyethyl acrylate can also be used. Additionally, isoprene, butadiene, isobutylene, vinyl ether, etc. can be mentioned.

In addition, as monomers that can be copolymerized other than the above, silane-based monomers containing silicon atoms, etc. can be mentioned. As silane monomers, for example, 3-acryloxypropyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, 4-vinylbutyltrimethoxysilane, 4-vinylbutyltriethoxysilane, 8- Vinyloctyltrimethoxysilane, 8-vinyloctyltriethoxysilane, 10-methacryloyloxydecyltrimethoxysilane, 10-acryloyloxydecyltrimethoxysilane, 10-methacryloyloxydecyltrimethoxysilane Ethoxysilane, 10-acryloyloxydecyltriethoxysilane, etc. are mentioned.

In addition, copolymerization monomers include tripropylene glycol di(meth)acrylate, tetraethylene glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, and bisphenol A diglycidyl ether di(meth)acrylate. Latex, neopentyl glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate, pentaerythritol tetra(meth)acrylate, dipentaerythritol penta(meth)acrylate, Double unsaturated products such as (meth)acryloyl group and vinyl group, such as esters of (meth)acrylic acid and polyhydric alcohol, such as dipentaerythritol hexa(meth)acrylate and caprolactone-modified dipentaerythritol hexa(meth)acrylate. Polyester in which two or more unsaturated double bonds such as (meth)acryloyl group or vinyl group are added to the skeleton of a polyfunctional monomer having two or more bonds, such as polyester, epoxy, or urethane, as a functional group similar to the monomer component. (meth)acrylate, epoxy (meth)acrylate, urethane (meth)acrylate, etc. can also be used.

The (meth)acrylic polymer contains alkyl (meth)acrylate as a main component in terms of the weight ratio of the monomers in the total composition, and the ratio of the copolymerized monomer in the (meth)acrylic polymer is not particularly limited, but the ratio of the copolymerized monomers in the total composition is In terms of the weight ratio of monomer, it is preferably about 0 to 20%, about 0.1 to 15%, and more preferably about 0.1 to 10%.

Among these copolymerized monomers, hydroxyl group-containing monomers and carboxyl group-containing monomers are preferably used from the viewpoint of adhesiveness and durability. Hydroxyl group-containing monomers and carboxyl group-containing monomers can be used together. These copolymerized monomers become reaction points with the crosslinking agent when the pressure-sensitive adhesive composition contains a crosslinking agent. Since hydroxyl group-containing monomers, carboxyl group-containing monomers, etc. have high reactivity with intermolecular crosslinking agents, they are preferably used to improve the cohesiveness and heat resistance of the resulting pressure-sensitive adhesive layer. Monomers containing hydroxyl groups are preferable in terms of reworkability, and monomers containing carboxyl groups are preferable in that they achieve both durability and reworkability.

When a hydroxyl group-containing monomer is contained as the copolymerization monomer, the ratio is preferably 0.01 to 15% by weight, more preferably 0.03 to 10% by weight, and further preferably 0.05 to 7% by weight. When a carboxyl group-containing monomer is contained as the copolymerization monomer, the ratio is preferably 0.05 to 10% by weight, more preferably 0.1 to 8% by weight, and further preferably 0.2 to 6% by weight.

The (meth)acrylic polymer of the present invention is usually used having a weight average molecular weight in the range of 500,000 to 3,000,000. Considering durability, especially heat resistance, it is preferable to use one with a weight average molecular weight of 700,000 to 2.7 million. Additionally, it is preferable that it is 800,000 to 2.5 million. If the weight average molecular weight is less than 500,000, it is undesirable from the viewpoint of heat resistance. Additionally, if the weight average molecular weight is greater than 3 million, a large amount of diluting solvent is required to adjust the viscosity for application, which is undesirable in that the cost increases. In addition, the weight average molecular weight is a value measured by GPC (gel permeation chromatography) and calculated by conversion to polystyrene.

For producing such (meth)acrylic polymers, known production methods such as solution polymerization, radiation polymerization such as UV polymerization, bulk polymerization, emulsion polymerization, and various radical polymerizations can be appropriately selected. Additionally, the resulting (meth)acrylic polymer may be any of random copolymers, block copolymers, and graft copolymers.

In addition, in solution polymerization, ethyl acetate, toluene, etc. are used as a polymerization solvent. As a specific example of solution polymerization, the reaction is carried out by adding a polymerization initiator under an inert gas stream such as nitrogen, and reaction conditions are usually about 50 to 70°C for about 5 to 30 hours.

The polymerization initiator, chain transfer agent, emulsifier, etc. used in radical polymerization are not particularly limited and can be appropriately selected and used. In addition, the weight average molecular weight of the (meth)acrylic polymer can be controlled by the usage amount of the polymerization initiator and chain transfer agent, and the reaction conditions, and the appropriate usage amount is adjusted depending on these types.

As a radical polymerization initiator, for example, 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-amidinopropane)dihydrochloride, 2,2'-azobis[2-(5 -methyl-2-imidazolin-2-yl)propane] dihydrochloride, 2,2'-azobis(2-methylpropionamidine) disulfate, 2,2'-azobis(N,N'- dimethyleneisobutylamidine), 2,2'-azobis[N-(2-carboxyethyl)-2-methylpropionamidine]hydrate (manufactured by Wako Pure Chemical Industries, Ltd., VA-057), etc. Co-initiator, persulfate such as potassium persulfate and ammonium persulfate, di(2-ethylhexyl)peroxydicarbonate, di(4-t-butylcyclohexyl)peroxydicarbonate, di-sec-butylperoxydicarbonate, t -Butyl peroxyneodecanoate, t-hexyl peroxypivalate, t-butyl peroxypivalate, dilauroyl peroxide, di-n-octanoyl peroxide, 1,1,3,3-tetra Methylbutylperoxy-2-ethylhexanoate, di(4-methylbenzoyl)peroxide, dibenzoyl peroxide, t-butylperoxyisobutyrate, 1,1-di(t-hexylperoxy)cyclohexane , peroxide-based initiators such as t-butylhydroperoxide and hydrogen peroxide, redox-based initiators combining peroxides and reducing agents, such as a combination of persulfate and sodium bisulfite, and a combination of peroxide and sodium ascorbate, but these It is not limited to.

The radical polymerization initiator may be used alone, or two or more types may be mixed, but the total content is preferably about 0.005 to 1 part by weight, and about 0.02 to 0.5 parts by weight, based on 100 parts by weight of monomer. It is more desirable.

As chain transfer agents, for example, lauryl mercaptan, glycidyl mercaptan, mercaptoacetic acid, 2-mercaptoethanol, thioglycolic acid, 2-ethylhexyl thioglycolic acid, 2,3-dimercapto-1- Propanol, etc. can be mentioned. The chain transfer agent may be used alone or in combination of two or more types, but the total content is approximately 0.1 part by weight or less with respect to 100 parts by weight of the total amount of the monomer component.

In addition, as emulsifiers used in emulsion polymerization, for example, anions such as sodium lauryl sulfate, ammonium lauryl sulfate, sodium dodecylbenzenesulfonate, ammonium polyoxyethylene alkyl ether sulfate, and sodium polyoxyethylene alkyl phenyl ether sulfate. and nonionic emulsifiers such as polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, polyoxyethylene fatty acid ester, and polyoxyethylene-polyoxypropylene block polymer. These emulsifiers may be used individually, or two or more types may be used in combination.

In addition, reactive emulsifiers include emulsifiers into which radically polymerizable functional groups such as propenyl groups and allyl ether groups are introduced, specifically, for example, AQUALON HS-10, HS-20, KH-10, BC-05, BC-10, BC-20 (above, all manufactured by DKS Co., Ltd.), ADEKA REASOAP SE10N (manufactured by Asahi Denka Kogyo K.K.), etc. Reactive emulsifiers are preferable because they improve water resistance because they are introduced into the polymer chain after polymerization. The amount of emulsifier used is preferably 0.3 to 5 parts by weight based on 100 parts by weight of the total amount of monomer components, and more preferably 0.5 to 1 part by weight from polymerization stability and mechanical stability.

<Cross-linking agent>

Additionally, in the present invention, a crosslinking agent may be contained in the adhesive composition that forms the adhesive layer. As a crosslinking agent, an organic crosslinking agent or a multifunctional metal chelate can be used. Examples of organic crosslinking agents include isocyanate crosslinking agents, peroxide crosslinking agents, epoxy crosslinking agents, and imine crosslinking agents. A multifunctional metal chelate is one in which a multivalent metal is covalently bonded or coordinated with an organic compound. Examples of polyvalent metal atoms include Al, Cr, Zr, Co, Cu, Fe, Ni, V, Zn, In, Ca, Mg, Mn, Y, Ce, Sr, Ba, Mo, La, Sn, and Ti. . Examples of atoms in organic compounds that form covalent bonds or coordinate bonds include oxygen atoms, and examples of organic compounds include alkyl esters, alcohol compounds, carboxylic acid compounds, ether compounds, and ketone compounds.

Compounds using isocyanate-based crosslinking agents include, for example, isocyanate monomers such as tolylene diisocyanate, chlorphenylene diisocyanate, tetramethylene diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, and hydrogenated diphenylmethane diisocyanate. Isocyanate compounds, isocyanurates, and biuret-type compounds obtained by adding isocyanate monomers such as trimethylolpropane, and urethane prepolymers obtained by addition reaction such as polyether polyol, polyester polyol, acrylic polyol, polybutadiene polyol, and polyisoprene polyol. Isocyanate, etc. can be mentioned. In particular, a polyisocyanate compound is preferably selected from the group consisting of hexamethylene diisocyanate, hydrogenated xylylene diisocyanate, and isophorone diisocyanate, or a polyisocyanate compound derived therefrom. Here, one type selected from the group consisting of hexamethylene diisocyanate, hydrogenated xylylene diisocyanate, and isophorone diisocyanate, or a polyisocyanate compound derived therefrom, includes hexamethylene diisocyanate, hydrogenated xylylene diisocyanate, and isophorone. Diisocyanate, polyol-modified hexamethylene diisocyanate, polyol-modified hydrogenated xylylene diisocyanate, trimer-type hydrogenated xylylene diisocyanate, and polyol-modified isophorone diisocyanate are included. The exemplified polyisocyanate compounds are particularly preferable as they contribute to the speed of crosslinking because the reaction with hydroxyl groups proceeds rapidly using acids and bases contained in the polymer as catalysts.

Peroxides can be used appropriately as long as they generate radical active species through heating or light irradiation and promote crosslinking of the base polymer of the adhesive composition. However, considering workability and stability, peroxides with a half-life temperature of 80°C to 160°C for 1 minute are used. It is preferable to use peroxide with a temperature of 90°C to 140°C.

Examples of the peroxide include di(4-t-butylcyclohexyl)peroxydicarbonate (half-life temperature for 1 minute: 92.1°C), di-sec-butylperoxydicarbonate (half-life temperature for 1 minute: 92.4°C), and t- Butylperoxyneodecanoate (1-minute half-life temperature: 103.5°C), t-hexylperoxypivalate (1-minute half-life temperature: 109.1°C), t-butylperoxypivalate (1-minute half-life temperature: 110.3°C) , dilauroyl peroxide (1 minute half-life temperature: 116.4°C), di-n-octanoyl peroxide (1 minute half-life temperature: 117.4°C), 1,1,3,3-tetramethylbutylperoxy-2 -Ethylhexanoate (half-life temperature for 1 minute: 124.3°C), di(4-methylbenzoyl)peroxide (half-life temperature for 1 minute: 128.2°C), dibenzoyl peroxide (half-life temperature for 1 minute: 130.0°C), t- Examples include butylperoxyisobutyrate (1-minute half-life temperature: 136.1°C) and 1,1-di(t-hexylperoxy)cyclohexane (1-minute half-life temperature: 149.2°C). Among them, di(4-t-butylcyclohexyl)peroxydicarbonate (1-minute half-life temperature: 92.1°C), dilauroyl peroxide (1-minute half-life temperature: 116.4°C), especially in terms of excellent crosslinking reaction efficiency. Dibenzoyl peroxide (1 minute half-life temperature: 130.0°C), etc. are preferably used.

In addition, the half-life of peroxide is an indicator of the decomposition rate of peroxide and refers to the time until the remaining amount of peroxide is reduced to half. The decomposition temperature for obtaining the half-life at an arbitrary time and the half-life time at an arbitrary temperature are described in the manufacturer's catalog, etc., for example, in NOF CORPORATION's "Organic Peroxide Catalog 9th Edition (May 2003)" etc. It is listed.

The amount of the crosslinking agent used is preferably 20 parts by weight or less, more preferably 0.01 to 20 parts by weight, and more preferably 0.03 to 10 parts by weight, based on 100 parts by weight of the base polymer such as a (meth)acrylic polymer in the adhesive composition. Additionally, if the crosslinking agent is more than 20 parts by weight, the moisture resistance is not sufficient and peeling is likely to occur in reliability tests, etc.

Additionally, the adhesive composition forming the adhesive layer with the pigment of the present invention may contain a silane coupling agent. Durability can be improved by using a silane coupling agent. Specific examples of silane coupling agents include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 2-(3,4 -Silane coupling agents containing epoxy groups such as epoxycyclohexyl)ethyltrimethoxysilane, 3-aminopropyltrimethoxysilane, N-2-(aminoethyl)-3-aminopropylmethyldimethoxysilane, 3-triethoxy Amino group-containing silane coupling agents such as silyl-N-(1,3-dimethylbutylidene)propylamine, N-phenyl-γ-aminopropyl trimethoxysilane, 3-acryloxypropyltrimethoxysilane, and 3-meta Silane coupling agents containing a (meth)acrylic group such as kryloxypropyltriethoxysilane, and silane coupling agents containing an isocyanate group such as 3-isocyanate propyltriethoxysilane.

The silane coupling agent may be used alone or in combination of two or more types, but the total content is preferably 0.001 to 5 parts by weight per 100 parts by weight of the base polymer such as the (meth)acrylic polymer. Also, 0.01 to 1 part by weight is preferable, more preferably 0.02 to 1 part by weight, and further preferably 0.05 to 0.6 part by weight. This is an amount that improves durability and maintains adequate adhesion to optical members such as liquid crystal cells.

Additionally, in the present invention, polyether-modified silicone can be blended in the adhesive composition that forms the adhesive layer with a pigment. As polyether-modified silicone, for example, those disclosed in Japanese Patent Application Laid-Open No. 2010-275522 can be used.

In addition, in the present invention, the adhesive composition forming the adhesive layer having a pigment may contain other known additives, for example, colorants, powders such as pigments, dyes, surfactants, plasticizers, tackifiers, Surface lubricants, leveling agents, softeners, anti-aging agents, antioxidants, light stabilizers, ultraviolet absorbers, polymerization inhibitors, inorganic or organic fillers, metal powders, particles, thin substances, etc. can be added appropriately depending on the intended use. Additionally, a redox system to which a reducing agent is added within a controllable range may be adopted.

A pigmented adhesive layer is formed using the adhesive composition. However, in forming the adhesive layer, it is desirable to adjust the addition amount of the crosslinking agent and sufficiently consider the influence of the crosslinking treatment temperature and crosslinking treatment time.

The crosslinking treatment temperature and crosslinking treatment time can be adjusted depending on the crosslinking agent used. The crosslinking treatment temperature is preferably 170°C or lower.

In addition, this crosslinking treatment may be performed at the temperature at the time of the drying process of the adhesive layer, or may be performed by setting a separate crosslinking treatment process after the drying process.

In addition, the crosslinking treatment time can be set in consideration of productivity and workability, but is usually about 0.2 to 20 minutes, and is preferably about 0.5 to 10 minutes.

As a method of forming a pressure-sensitive adhesive layer with a pigment, for example, the pressure-sensitive adhesive composition is applied to a separator that has been subjected to a peeling treatment, the polymerization solvent, etc. is dried and removed to form an adhesive layer, and then the pressure-sensitive adhesive layer is transferred to a polarizing film. It is produced by, for example, a method of applying the adhesive composition, drying and removing the polymerization solvent, etc., to form an adhesive layer on a polarizing film. In addition, when applying the adhesive, one or more solvents other than the polymerization solvent may be newly added as appropriate.

As the separator subjected to the release treatment, a silicone release liner is preferably used. In the process of forming an adhesive layer by applying and drying the adhesive composition of the present invention on such a liner, a method suitable for drying the adhesive may be adopted depending on the purpose. Preferably, a method of overheating and drying the coating film is used. The heat drying temperature is preferably 40°C to 200°C, more preferably 50°C to 180°C, and particularly preferably 70°C to 170°C. By keeping the heating temperature within the above range, an adhesive with excellent adhesive properties can be obtained.

Any appropriate drying time may be adopted. The drying time is preferably 5 seconds to 20 minutes, more preferably 5 seconds to 10 minutes, and particularly preferably 10 seconds to 5 minutes.

In addition, the adhesive layer can be formed after forming an anchor layer on the surface of the polarizing film or performing various easy-adhesion treatments such as corona treatment and plasma treatment. Additionally, you may perform an easy-adhesion treatment on the surface of the adhesive layer.

As a method of forming the adhesive layer, various methods are used. Specifically, for example, roll coating, kiss roll coating, gravure coating, reverse coating, roll brush, spray coating, dip roll coating, bar coating, knife coating, air knife coating, curtain coating, lip coating, die coater, etc. Methods such as extrusion coating method can be mentioned.

The thickness of the adhesive layer is not particularly limited, and is, for example, about 1 to 100 μm. It is preferably 2 to 50 μm, more preferably 2 to 40 μm, and even more preferably 5 to 35 μm.

<Film layer>

Additionally, the optical functional layer of the present invention includes a film layer containing a dye, and the film layer can be formed from a composition containing a base polymer for film formation and a dye. Examples of the base polymer material forming the film layer include those similar to the materials constituting the transparent protective film described later. In particular, cellulose resins such as triacetylcellulose, polyester resins, (meth)acrylic resins, cyclic polyolefin resins (norbornene-based resins), etc. are preferably used as the materials. The film layer can be applied to the first polarizing film and the second polarizing film using an adhesive, pressure-sensitive adhesive, etc. as appropriate.

Various methods can be employed to form the film layer containing the pigment. For example, when dissolving the pellets of the resin material in a solvent, a pigment can be mixed to prepare a composition, and the film layer can be produced by casting or extruding the composition. At that time, the film layer can be formed to an appropriate thickness. In preparing the composition, additives may be appropriately added.

The thickness of the film layer is not particularly limited and is the same as that of the adhesive layer, for example, about 1 to 100 μm. It is preferably 2 to 50 μm, more preferably 2 to 40 μm, and even more preferably 5 to 35 μm.

When the optical function layer (especially the adhesive layer) is exposed, the optical function layer (especially the adhesive layer) may be protected with a peeled sheet (separator) until it is put to practical use.

As constituent materials of the separator, for example, plastic films such as polyethylene, polypropylene, polyethylene terephthalate, and polyester film, porous materials such as paper, cloth, and nonwoven fabric, nets, foam sheets, metal foil, and laminates thereof, etc. Suitable thin films may be mentioned, but plastic films are suitably used because they have excellent surface smoothness.

The plastic film is not particularly limited as long as it is a film that can protect the optical function layer (especially the adhesive layer), and examples include polyvinyl alcohol film, polyethylene film, polypropylene film, polybutene film, polybutadiene film, poly Examples include methylpentene film, polyvinyl chloride film, vinyl chloride copolymer film, polyethylene terephthalate film, polybutylene terephthalate film, polyurethane film, and ethylene-vinyl acetate copolymer film.

The thickness of the separator is usually about 5 to 200 μm, preferably about 5 to 100 μm. If necessary, the separator may be subjected to mold release and antifouling treatment using a silicone-based, fluorine-based, long-chain alkyl-based or fatty acid amide-based release agent, silica powder, etc., or antistatic treatment such as coating type, kneading type, or vapor deposition type. In particular, peelability from the optical function layer (especially the adhesive layer) can be further improved by appropriately performing a peeling treatment such as silicone treatment, long-chain alkyl treatment, or fluorine treatment on the surface of the separator.

In addition, the optical function layer is applied to a liquid crystal cell to form a liquid crystal panel, but when the optical function layer is an adhesive layer, it can be used as a polarizing film with an adhesive layer attached in advance by forming an adhesive layer on the polarizing film when bonding to the liquid crystal cell. You can. The peeled sheet used in the production of the polarizing film with an adhesive layer can be used as is as a separator for the polarizing film with an adhesive layer, and the process can be simplified.

<Polarizing film>

As the first and second polarizing films of the present invention, those having a transparent protective film on one or both sides of the polarizer are generally used.

The polarizer is not particularly limited, and various types of polarizers can be used. As a polarizer, for example, a dichroic substance such as iodine or a dichroic dye is adsorbed on a hydrophilic polymer film such as a polyvinyl alcohol-based film, a partially formalized polyvinyl alcohol-based film, or an ethylene-vinyl acetate copolymer-based partially saponified film, and a uniaxial polarizer is formed. Examples include polyene-based oriented films such as stretched ones, dehydrated products of polyvinyl alcohol, and dehydrochlorinated products of polyvinyl chloride. Among these, polarizers made of dichroic substances such as polyvinyl alcohol-based films and iodine are suitable. The thickness of these polarizers is not particularly limited, but is generally about 80 μm or less.

A polarizer obtained by dyeing a polyvinyl alcohol-based film with iodine and stretching it uniaxially can be created, for example, by immersing a polyvinyl alcohol-based film in an aqueous solution of iodine, dyeing it, and stretching it to 3 to 7 times the original length. If necessary, it may be immersed in an aqueous solution of potassium iodide, which may contain boric acid, zinc sulfate, zinc chloride, etc. Additionally, if necessary, the polyvinyl alcohol-based film may be immersed in water and washed before dyeing. By washing the polyvinyl alcohol-based film with water, contamination and anti-blocking agents can be removed from the surface of the polyvinyl alcohol-based film, and swelling of the polyvinyl alcohol-based film also has the effect of preventing unevenness such as staining in dyeing. Stretching may be carried out after dyeing with iodine, may be carried out while dyeing, or may be carried out after stretching and then dyed with iodine. It can be stretched even in an aqueous solution such as boric acid or potassium iodide or in a water bath.

Additionally, as a polarizer, a thin polarizer with a thickness of 10 μm or less can be used. From the viewpoint of thinning, the thickness is preferably 1 to 7 μm. Such a thin polarizer has little variation in thickness, has excellent visibility, and is excellent in durability due to little dimensional change. It is also desirable that the thickness of the polarizing film can be reduced.

Representative thin polarizers include Japanese Patent Application Laid-Open No. 51-069644, Japanese Patent Application Laid-Open No. 2000-338329, pamphlet WO2010/100917, specification of PCT/JP2010/001460, or Japanese Patent Application No. 2010-269002. A thin polarizing film described in the specification or Japanese Patent Application No. 2010-263692 can be mentioned. These thin polarizing films can be obtained by a manufacturing method including a step of stretching a polyvinyl alcohol-based resin (hereinafter also referred to as PVA-based resin) layer and a resin substrate for stretching in the state of a laminate, and a dyeing step. With this manufacturing method, even if the PVA-based resin layer is thin, it is supported by the resin base material for stretching, making it possible to stretch without problems such as breakage during stretching.

The above-described thin polarizing film can be stretched at a high magnification among manufacturing methods that include a process of stretching to form a laminate and a dyeing process, and thus polarization performance can be improved, so it can be used in pamphlet WO2010/100917 and PCT/JP2010/001460. It is preferably obtained by a manufacturing method including a step of stretching in an aqueous boric acid solution as described in the specification or Japanese Patent Application No. 2010-269002 or the specification of Japanese Patent Application No. 2010-263692, and especially in Japanese Patent Application No. 2010-269002. It is preferable to obtain it by a manufacturing method including a step of auxiliary stretching in air before stretching in an aqueous boric acid solution described in the specification or Japanese Patent Application No. 2010-263692.

As a material constituting the transparent protective film, for example, a thermoplastic resin excellent in transparency, mechanical strength, thermal stability, moisture barrier, isotropy, etc. is used. Specific examples of such thermoplastic resins include cellulose resins such as triacetylcellulose, polyester resins, polyethersulfone resins, polysulfone resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins, (meth)acrylic resins, and cyclic resins. Examples include polyolefin resin (norbornene-based resin), polyarylate resin, polystyrene resin, polyvinyl alcohol resin, and mixtures thereof. In addition, a transparent protective film is bonded to one side of the polarizer with an adhesive layer, but on the other side, a thermosetting resin such as (meth)acrylic, urethane, acrylic urethane, epoxy, or silicone or ultraviolet curable resin can be used as a transparent protective film. . The transparent protective film may contain one or more suitable additives. Examples of additives include ultraviolet absorbers, antioxidants, lubricants, plasticizers, mold release agents, discoloration inhibitors, flame retardants, nucleating agents, antistatic agents, pigments, colorants, etc. The content of the thermoplastic resin in the transparent protective film is preferably 50 to 100% by weight, more preferably 50 to 99% by weight, further preferably 60 to 98% by weight, and particularly preferably 70 to 97% by weight. If the content of the thermoplastic resin in the transparent protective film is 50% by weight or less, there is a risk that the inherent high transparency of the thermoplastic resin may not be sufficiently expressed.

The thickness of the transparent protective film is not particularly limited, and is, for example, about 10 to 90 μm. Preferably it is 15 to 60㎛, more preferably 20 to 50㎛.

A functional layer (surface layer) such as a hard coat layer, an anti-reflection layer, an anti-sticking layer, a diffusion layer, or an anti-glare layer may be formed on the surface of the transparent protective film that does not adhere the polarizer.

The adhesive used to bond the polarizer and the transparent protective film is not particularly limited as long as it is optically transparent, and various types of adhesives such as water-based, solvent-based, hot melt-based, radical-curing, and cation-curing types are used, but water-based or radical-curing adhesives are suitable. do.

<Liquid crystal panel>

As described above, the liquid crystal panel of the present invention includes, for example, a liquid crystal cell, a first optical function layer and a first polarizing film disposed on a viewing side from the liquid crystal cell, and a second optical function disposed on a back side from the liquid crystal cell. layer and a second polarizing film. In addition to the polarizing film, other optical layers can be applied to form a liquid crystal panel. There is no particular limitation on the optical layer, but for example, it can be used in liquid crystal panels such as reflectors, transflectors, retardation plates (including 1/2 or 1/4 wave plates), visual compensation films, and brightness enhancement films. The optical layer that may be used for formation can be used as one layer or two or more layers on the viewing side and/or back side of the liquid crystal cell.

<Liquid crystal display device>

In a liquid crystal display device, a predetermined backlight unit is combined according to a predetermined maximum absorption wavelength of the liquid crystal panel. A backlight unit can be prepared by combining light sources to satisfy the following characteristics.

When using the liquid crystal panel having a maximum absorption wavelength in the wavelength range of 570 to 610 nm,

As the backlight unit,

It has a peak intensity (Gp) of the emission spectrum in the wavelength range of 515 to 545 nm,

It has a peak intensity (Rp) of the emission spectrum in the wavelength range of 605 to 650 nm, and also has

The Gp, the Rp, and the average value (Ave1) of the intensity of the emission spectrum in the wavelength range of 580 to 600 nm are expressed by the following formula (1)

Ave1≤0.3×{(Gp+Rp)/2} (1)

Those that satisfy are used.

In addition, when using the liquid crystal panel having a maximum absorption wavelength in the wavelength range of 470 to 510 nm,

As the backlight unit,

It has a peak intensity (Bp) of the emission spectrum in the wavelength range of 430 to 480 nm,

It has a peak intensity (Gp) of the emission spectrum in the wavelength range of 515 to 545 nm, and also has

The average value (Ave2) of the Bp, the Gp, and the intensity of the emission spectrum in the wavelength range of 480 to 500 nm is expressed by the following formula (2)

Ave2≤0.15×{(Bp+Gp)/2} (2)

Those that satisfy are used.

In addition, the wavelength range of 570 to 610 nm or 470 to 510 nm based on the maximum absorption wavelength in the liquid crystal panel, and the wavelength range of 580 to 600 nm or wavelength range based on the calculation of Ave1 included in the backlight. Although there is a difference between 480 and 500 nm, it was found that the effect of suppressing the decrease in luminance in the present invention is obtained when the wavelength range by the maximum absorption wavelength by the liquid crystal panel is wider than the wavelength range by the backlight.

Figure 2 is a graph showing an example of the emission spectrum of the backlight unit. In Figure 2, the peak intensity (Bp), peak intensity (Gp), and peak intensity (Rp) in each wavelength range are shown. In addition, in Figure 2, Ave1 (average value of the intensity of the emission spectrum) in w1 (wavelength range 580 to 600 nm) and Ave2 (average value of the intensity of the emission spectrum) in w2 (wavelength range 480 to 500 nm) are conceptually represented. It is indicated as .

Having a peak intensity (Gp) in the above wavelength range indicates that the wavelength range of the G spectrum is narrow, having a peak intensity (Rp) in the above wavelength range indicates that the wavelength range of the R spectrum is narrow, and between the G spectrum and the R spectrum. This indicates that the intensity of the emission spectrum in the wavelength range (the part where colors are mixed) becomes relatively small. In addition, satisfying the equation (1): Ave1≤0.3 This indicates that the intensity of the emission spectrum (the part where colors are mixed) is absolutely small. In this way, the liquid crystal display device of the present invention is designed to reduce the overlap between the wavelength range where light is absorbed by the liquid crystal panel and the wavelength range of the backlight's emission spectrum in wavelength ranges other than RGB (part where colors are mixed), and optical color gamut is achieved. It is possible to suppress the decline in luminance while satisfying .

The coefficient "0.3" in the above formula (1) is preferably 0.25, and is preferably 0.2 from the above design point of view.

Having a peak intensity (Bp) in the above wavelength range indicates that the wavelength range of the B spectrum is narrow, having a peak intensity (Gp) in the above wavelength range indicates that the wavelength range of the G spectrum is narrow, and between the B spectrum and the G spectrum. This indicates that the emission spectrum in the wavelength range (the part where colors are mixed) becomes relatively small. In addition, satisfying the above formula (2): Ave2≤0.15 This indicates that the emission spectrum in the wavelength range (the part where colors are mixed) is absolutely small. In this way, the liquid crystal display device of the present invention is designed to reduce the overlap between the wavelength range where light is absorbed by the liquid crystal panel and the wavelength range of the backlight's emission spectrum in wavelength ranges other than RGB (part where colors are mixed), and optical color gamut is achieved. It is possible to suppress the decline in luminance while satisfying .

The coefficient "0.15" in the above equation (2) is preferably 0.13, and is further preferably 0.1.

In addition, the liquid crystal display device of the present invention uses a liquid crystal panel having a maximum absorption wavelength in the wavelength range of 570 to 610 nm and 470 to 510 nm, and also has a backlight that satisfies the above equations (1) and (2). The unit can be used.

The liquid crystal display device of the present invention is formed by appropriately assembling a backlight unit to the liquid crystal panel and mounting a driving circuit thereon. In addition, in the formation of a liquid crystal display device, one or two or more layers of appropriate components such as a diffusion plate, anti-glare layer, anti-reflection film, protective plate, prism array, lens array sheet, and light diffusion plate are placed at appropriate positions. can do. Other reflectors, etc. can be used.

(Example)

The present invention will be described in detail below by way of examples, but the present invention is not limited to these examples. In addition, the parts and percentages in each example are all based on weight. All room temperature leaving conditions unless specifically specified below are 23°C 65%RH.

<Measurement of weight average molecular weight of (meth)acrylic polymer>

The weight average molecular weight (Mw) of the (meth)acrylic polymer was measured by GPC (gel permeation chromatography). Mw/Mn was similarly measured.

·Analysis device: HLC-8120GPC, manufactured by Tosoh Corporation

Column: Tosoh Corporation, G7000H _XL +GMH _XL +GMH _XL

·Column size: 7.8mmϕ×30cm each, 90cm in total

·Column temperature: 40℃

·Flow rate: 0.8mL/min

·Injection volume: 100μL

·Eluent: Tetrahydrofuran

Detector: Differential refractometer (RI)

·Standard sample: polystyrene

(i) Fabrication of optical compensation layer

Polymerization was performed using a batch polymerization apparatus consisting of two vertical reactors equipped with stirring blades and a reflux condenser controlled at 100°C. 9,9-[4-(2-hydroxyethoxy)phenyl]fluorene (BHEPF), isosorbide (ISB), diethylene glycol (DEG), diphenylcarbonate (DPC), and magnesium acetate tetrahydrate. It was injected so that the molar ratio was BHEPF/ISB/DEG/DPC/magnesium acetate = 0.348/0.490/0.162/1.005/1.00×10 ^-5 . After sufficiently purging the inside of the reactor with nitrogen (oxygen concentration 0.0005 to 0.001 vol%), heating was performed using a heating medium, and stirring was started when the internal temperature reached 100°C. 40 minutes after the start of the temperature increase, the internal temperature reached 220°C, and while controlling to maintain this temperature, pressure reduction was started, and the temperature was set to 13.3 kPa for 90 minutes after reaching 220°C. The phenol vapor produced by the polymerization reaction was guided to a reflux cooler at 100°C, and the monomer component contained in a small amount in the phenol vapor was returned to the reactor, and the uncondensed phenol vapor was guided to a condenser at 45°C for recovery.

Nitrogen was introduced into the first reactor to restore the pressure to atmospheric pressure, and then the oligomerized reaction solution in the first reactor was transferred to the second reactor. Next, the temperature increase and pressure reduction in the second reactor were started, and the internal temperature was 240°C and the pressure was 0.2 kPa for 50 minutes. Thereafter, polymerization was allowed to proceed until the desired stirring power was reached. At the point when the predetermined power is reached, nitrogen is introduced into the reactor to restore pressure, the reaction solution is extracted in the form of strands, and pelletized with a rotary cutter to copolymerize BHEPF/ISB/DEG=34.8/49.0/16.2[mol%] A polycarbonate resin with the following composition was obtained. The reduced viscosity of this polycarbonate resin was 0.430 dL/g and the glass transition temperature was 128°C.

The obtained polycarbonate resin (10 kg) was dissolved in methylene chloride (73 kg) to prepare a coating liquid. Next, the above coating liquid was applied directly onto a shrinkable film (longitudinal uniaxially stretched polypropylene film, manufactured by TOKYO PRINTING INK MFG. CO., LTD., brand name “NOBLEN”), and the coating film was dried at a drying temperature of 30°C for 5 minutes. , and dried at 80°C for 5 minutes to form a laminate of shrinkable film/birefringent layer. The obtained laminate was stretched at a shrinkage ratio of 0.80 in the MD direction and 1.3 times in the TD direction at a stretching temperature of 155°C using a simultaneous biaxial stretching machine to form a retardation film on the shrinkable film. Next, the retardation film was peeled from the shrinkable film. The thickness of the retardation film was 60.0㎛, Re(550)=140nm, Nz=0.5, Re(450)/Re(550)=0.89. This retardation film was used as an optical compensation layer.

(ii) Fabrication of polarizer

A long roll of a 30㎛ thick polyvinyl alcohol (PVA)-based resin film (manufactured by Kuraray Co., Ltd., product name “PE3000”) is stretched uniaxially in the longitudinal direction to a length of 5.9 times by a roll stretching machine and simultaneously swelled. , dyeing, crosslinking, washing, and finally drying was performed to produce a polarizer with a thickness of 12 μm.

Specifically, the swelling treatment was performed with pure water at 20°C and stretched 2.2 times. Next, the dyeing treatment was carried out in an aqueous solution at 30°C where the iodine concentration was adjusted so that the resulting polarizer had a single transmittance of 45.0% and the weight ratio of iodine and potassium iodide was 1:7, and the film was stretched 1.4 times. In addition, the crosslinking treatment adopted a two-stage crosslinking treatment, and the first stage crosslinking treatment was carried out in an aqueous solution of boric acid and potassium iodide at 40°C and stretched 1.2 times. The boric acid content of the aqueous solution in the first stage crosslinking treatment was 5.0% by weight, and the potassium iodide content was 3.0% by weight. The second stage crosslinking treatment was carried out in an aqueous solution of boric acid and potassium iodide at 65°C and stretched 1.6 times. The boric acid content of the aqueous solution in the second stage crosslinking treatment was 4.3% by weight, and the potassium iodide content was 5.0% by weight. Additionally, the washing treatment was performed with an aqueous potassium iodide solution at 20°C. The potassium iodide content of the aqueous solution for washing treatment was set to 2.6% by weight. Finally, the drying treatment was performed at 70°C for 5 minutes to obtain a polarizer.

(iii) Production of polarizing film

HC-TAC film (thickness: 32㎛, protective layer) having a hard coat (HC) layer formed by hard coating on one side of the triacetylcellulose (TAC) film through a polyvinyl alcohol-based adhesive on one side of the polarizer. (corresponding) was bonded by roll-to-roll to obtain a long polarizing film having a protective layer/polarizer configuration.

(iv) Production of polarizing film with attached optical compensation layer

The polarizing film and optical compensation layer obtained above are cut to a predetermined size, and the polarizer surface of the polarizing film and the optical compensation layer are bonded through an acrylic adhesive to form an optical compensation layer having the structure of a protective layer/polarizer/optical compensation layer. A polarizing film was obtained. Additionally, the optical compensation layer was cut so that when the polarizing film and the optical compensation layer were bonded, the angle formed between the absorption axis of the polarizer and the slow axis of the optical compensation layer was 45°.

<Preparation of (meth)acrylic polymer>

A monomer mixture containing 100 parts of butyl acrylate, 0.01 part of 2-hydroxyethyl acrylate, and 5 parts of acrylic acid was charged into a reaction vessel equipped with a cooling pipe, a nitrogen introduction pipe, a thermometer, and a stirring device. In addition, 0.1 part of 2,2'-azobisisobutyronitrile as a polymerization initiator was injected with 100 parts of ethyl acetate for 100 parts of the monomer mixture, and nitrogen gas was introduced while gently stirring to replace nitrogen, and then the liquid temperature in the flask was changed to nitrogen gas. was maintained at around 55°C and a polymerization reaction was performed for 8 hours to prepare a solution (solid content concentration: 30% by weight) of an acrylic polymer with a weight average molecular weight (Mw) of 1.8 million and Mw/Mn = 4.1.

(Preparation of adhesive composition used in reference examples and reference comparative examples)

Regarding 100 parts of solid content of the acrylic polymer solution prepared above,

An adhesive composition was obtained by mixing 0.3 part of benzoyl peroxide (trade name: NYPER BMT, manufactured by NOF Corporation) and 1 part of an isocyanate-based crosslinking agent (brand name: CORONATE L, manufactured by Tosoh Corporation).

(Preparation of adhesive composition used in Examples and Comparative Examples)

Regarding 100 parts of solid content of the acrylic polymer solution prepared above,

0.3 parts of benzoyl peroxide (trade name: NYPER BMT, manufactured by NOF Corporation), 1 part of isocyanate-based crosslinking agent (brand name: CORONATE L, manufactured by Tosoh Corporation),

0.25 part, 0.5 part, or 1 part of a tetraazaporphyrin-based dye (product name PD-320 manufactured by Yamamoto Chemicals, Inc.; has a maximum absorption wavelength of 595 nm), and

An adhesive composition was obtained by mixing 0.5 parts of a phenolic antioxidant (trade name IRGANAOX1010 manufactured by BASF Japan Ltd.).

(Production of polarizing film with adhesive layer attached)

The adhesive composition was uniformly applied with an applicator to the surface of a polyethylene terephthalate film release substrate (MRF38CK manufactured by Mitsubishi Plastics, Inc.) treated with a silicone-based release agent, and dried in an air-circulating constant temperature oven at 155°C for 2 minutes to obtain a thickness. A 20 μm adhesive layer was formed. Next, a separator film with an adhesive layer formed on it was attached to the optical compensation layer side of the polarizing film with an optical compensation layer attached thereto, thereby producing a polarizing film with an optical compensation layer attached thereon.

(Production of liquid crystal panel)

A liquid crystal panel (base glass: TFT glass on the viewing side and CF glass on the backlight side) was taken out from a liquid crystal TV (product name: 43UH7710) manufactured by LG Corporation, and the polarizing film with adhesive layers on both sides was removed from the liquid crystal cell. . A separator is peeled from the adhesive layer of the polarizing film with the adhesive layer attached on both sides of the liquid crystal cell from which the polarizing film with the adhesive layer attached is removed, and then the adhesive layer of the polarizing film with the adhesive layer attached is bonded to the liquid crystal cell. Made a panel.

In the reference examples and reference comparative examples, a polarizing film with an adhesive layer having an adhesive layer similar to the above was used except that both sides of the liquid crystal cell did not have a pigment.

In the examples and comparative examples, a polarizing film with an adhesive layer having an adhesive layer with a pigment was used on the viewing side of the liquid crystal cell, and a polarizing film with an adhesive layer with an adhesive layer without a pigment was used on the backlight side. In addition, in the Examples and Comparative Examples, in the preparation of a polarizing film with an adhesive layer having an adhesive layer having a pigment, the pigment mixed in the adhesive composition forming the adhesive layer was changed as shown in Table 1.

(backlight)

Only the backlight (light source) was taken from the following products.

Light source: Its composition: The product name from which the light source is derived is as follows.

CD: BLED+QD(Green)+QD(Red): Kindle Fire HD 7 from Amazon.com, Inc.

CdFreeQD: BLED+CdFreeQD(Green)+QDCdFree(Red): UN65JS9000FXZA manufactured by Samsung Corporation

KSF: BLED+Phosphor0(Green)+KSF(Red): xperia z4 tablet manufactured by Sony Corporation

Phosphor (1): BLED+Phosphor1(Green)+phosphor1(Red) 43UF7500 manufactured by LG Corporation

Phosphor (2): BLED+Phosphor2(Green)+phosphor2(Red) 43UH7710 manufactured by LG Corporation

The emission spectrum of each backlight is shown in Table 1.

The luminescence spectrum was measured with SR-UL1 manufactured by TOPCON TECHNOHOUSE CORPORATION.

Reference Examples 1 to 3, Examples 1 to 3, Comparative Reference Examples 1 to 2, Comparative Examples 1 to 2

As shown in Table 1, a liquid crystal display device was produced by combining the liquid crystal panel and backlight produced above.

The following evaluation was performed on the liquid crystal panel and liquid crystal display device obtained in the above Reference Examples, Examples, Comparative Reference Examples, and Comparative Examples. The evaluation results are shown in Table 1.

(Measurement of luminance)

The liquid crystal display device manufactured in each example was placed in a dark room, and the front luminance during white display was measured using a color luminance meter (SR-UL1 manufactured by TOPCON TECHNOHOUSE CORPORATION). Table 1 also shows the reduction rate (%) of brightness based on the brightness (brightness of reference or comparative reference examples) when a pressure-sensitive adhesive layer without pigment is used.

Decrease rate of luminance (%) = [{(Brightness of reference example or comparative reference example) - (Brightness of example or comparative example)}/(Brightness of reference example or comparative reference example)] × 100

(Measurement of reflectance of liquid crystal panel)

The liquid crystal panel produced in each example was measured by a method not including regular reflection (SCE) using a D65 light source using the product name "CM-2600d" manufactured by KONICA MINOLTA, INC. The measurement temperature was 23°C. The average value of two repetitions was taken as the measurement value.

Table 1 also shows the rate of decrease in reflectance (%) based on the reflectance (reflectance of reference examples or comparative reference examples) when a pressure-sensitive adhesive layer without pigment is used.

Decrease rate of reflectance (%) = [{(reflectance of reference example or comparative reference example) - (reflectivity of example or comparative example)}/(reflectance of reference example or comparative reference example)] × 100

<Measurement of transmittance of adhesive layer>

Using the liquid crystal panels obtained in the above Reference Examples, Examples, Comparative Reference Examples, and Comparative Examples, and a standard backlight taken from a liquid crystal TV manufactured by LG Corporation (Product Name: 43UH7710) used in the production of the liquid crystal panel, the following method was used. The “maximum absorption wavelength” transmittance of the adhesive layer was measured. The following luminance used data at each 595 nm based on spectral data measured using a color luminance meter (SR-UL1 manufactured by TOPCON TECHNOHOUSE CORPORATION).

(1) A liquid crystal display device was manufactured by assembling the liquid crystal panel obtained in the examples and comparative examples and a standard backlight, and the luminance (L ₅₉₅ (n)) of the liquid crystal display device was measured.

(2) Reference examples and comparisons A liquid crystal display device was manufactured by assembling the liquid crystal panel used in the reference example and a standard backlight, and the luminance (L ₅₉₅ (ref)) of the liquid crystal display device was measured.

From these, the transmittance of the maximum absorption wavelength of the adhesive layer was derived from the following equation.

Transmittance of the maximum absorption wavelength of the adhesive layer (%) = [L ₅₉₅ (n)/L ₅₉₅ (ref)] × 100

In addition, the adhesive layers used in the examples and comparative examples all had the same composition (the amount of change in the amount of pigment mixed was also the same). Therefore, the transmittances of the pressure-sensitive adhesive layers containing the same amount of dye in the examples and comparative examples are all the same. The transmittance of the reference example and comparative reference example was written as 100 (%), which represents the value of [L ₅₉₅ (ref)/L ₅₉₅ (ref)].

As shown in Table 1, it was confirmed that the rate of decline in luminance of the Examples was smaller than that of the Comparative Examples. In addition, the optical functional layer (adhesive layer) containing the dye is thought to have the function of lowering the reflectance as a function of the dye itself, but the rate of decrease in luminance in the examples is smaller than the rate of decrease in reflectance, and in the present invention, the rate of decrease in luminance is effectively lowered. The decline is suppressed.

PN: Liquid crystal panel C: Liquid crystal cell
A1: First optical functional layer A2: Second optical functional layer
P1: first polarizing film P2: second polarizing film
BL: backlight

Claims (12)

A liquid crystal display device having a liquid crystal cell, a liquid crystal panel having a first polarizing film disposed on a viewing side of the liquid crystal cell, and a second polarizing film disposed on a back side of the liquid crystal cell, and a backlight unit,
The liquid crystal panel has a maximum absorption wavelength in the wavelength range of 570 to 610 nm, and
The liquid crystal panel has a first optical functional layer disposed on a viewing side of the liquid crystal cell, and a second optical functional layer disposed on a back side of the liquid crystal cell. Among the first optical functional layer and the second optical functional layer, At least one optical functional layer contains a pigment having a maximum absorption wavelength in the wavelength range of 570 to 610 nm,
The backlight unit is,
It has a peak intensity (Gp) of the emission spectrum in the wavelength range of 515 to 545 nm,
It has a peak intensity (Rp) of the emission spectrum in the wavelength range of 605 to 650 nm, and also has
The Gp, the Rp, and the average value (Ave1) of the intensity of the emission spectrum in the wavelength range of 580 to 600 nm are expressed by the following formula (1)
Ave1≤0.3×{(Gp+Rp)/2} (1)
A liquid crystal display device characterized in that it satisfies the following. delete According to claim 1,
A liquid crystal display device, wherein at least one of the first optical functional layer and the second optical functional layer has a transmittance of the maximum absorption wavelength of 50% or less. According to claim 3,
A liquid crystal display device, wherein at least the first optical function layer contains the dye. According to claim 3,
A liquid crystal display device, characterized in that the dye is a tetraazaporphyrin-based dye. According to any one of claims 3 to 5,
A liquid crystal display device characterized in that the dye is contained in an amount of 0.01 to 5 parts by weight based on 100 parts by weight of the solid weight of the base material forming the resin layer of the optical function layer. A liquid crystal display device having a liquid crystal cell, a liquid crystal panel having a first polarizing film disposed on a viewing side of the liquid crystal cell, and a second polarizing film disposed on a back side of the liquid crystal cell, and a backlight unit,
The liquid crystal panel has a maximum absorption wavelength in the wavelength range of 470 to 510 nm, and
The liquid crystal panel has a first optical functional layer disposed on a viewing side of the liquid crystal cell, and a second optical functional layer disposed on a back side of the liquid crystal cell. Among the first optical functional layer and the second optical functional layer, At least one optical functional layer contains a pigment having a maximum absorption wavelength in the wavelength range of 470 to 510 nm,
The backlight unit is,
It has a peak intensity (Bp) of the emission spectrum in the wavelength range of 430 to 480 nm,
It has a peak intensity (Gp) of the emission spectrum in the wavelength range of 515 to 545 nm, and also has
The average value (Ave2) of the Bp, the Gp, and the intensity of the emission spectrum in the wavelength range of 480 to 500 nm is expressed by the following formula (2)
Ave2≤0.15×{(Bp+Gp)/2} (2)
A liquid crystal display device characterized in that it satisfies the following. delete According to claim 7,
A liquid crystal display device, wherein at least one of the first optical functional layer and the second optical functional layer has a transmittance of the maximum absorption wavelength of 50% or less. According to clause 9,
A liquid crystal display device, wherein at least the first optical function layer contains the dye. According to clause 9,
A liquid crystal display device, wherein the dye is at least one selected from tetraazaporphyrin-based dyes and cyanine-based dyes. The method according to any one of claims 9 to 11,
A liquid crystal display device characterized in that the dye is contained in an amount of 0.01 to 5 parts by weight based on 100 parts by weight of the solid weight of the base material forming the resin layer of the optical function layer.