JP6224016B2 - Composition for wavelength conversion layer, wavelength conversion member, backlight unit, and liquid crystal display device - Google Patents

Description

  The present invention relates to a wavelength conversion layer composition, a wavelength conversion member, a backlight unit, and a liquid crystal display device.

  A flat panel display such as a liquid crystal display device (Liquid Crystal Display (abbreviated as LCD for short)) has a low power consumption, and its use is expanding year by year as a space-saving image display device. The liquid crystal display device is composed of at least a backlight and a liquid crystal cell, and usually further includes members such as a backlight side polarizing plate and a viewing side polarizing plate.

  2. Description of the Related Art In recent years, for the purpose of improving the color reproducibility of LCDs, the wavelength conversion member of a backlight unit includes a wavelength conversion layer that includes quantum dots (also referred to as Quantum Dot, QD, or quantum dots) as a light emitting material. Is attracting attention. The wavelength conversion member is a member that converts the wavelength of light incident from a light source and emits it as white light. In a wavelength conversion layer that includes quantum dots as a light emitting material, two or three types of quantum having different light emission characteristics are used. White light can be realized using fluorescence in which dots are excited by light incident from a light source to emit light.

  Fluorescence due to quantum dots has high luminance and a small half-value width, so that LCDs using quantum dots are excellent in color reproducibility. With the progress of the three-wavelength light source technology using such quantum dots, the color reproduction range of the LCD is changed from the current TV standard (FHD (Full High Density), NTSC (National Television System Committee) ratio from 72% to 100%. And expanding.

  As a wavelength conversion layer including quantum dots, for example, Patent Document 1 discloses a wavelength conversion layer in which quantum dots are dispersed in an epoxy resin. The epoxy resin is cured by addition polymerization of a two-component mixture of an epoxy monomer and an amine. Epoxy resin is a preferable material because it has a low oxygen permeability and can prevent side reactions with oxygen in the quantum dots. Patent Document 2 discloses a fluorescent resin composition containing a phosphor, an epoxy, and an alkoxysilane compound. Amines and salts thereof are described as curing accelerators for curing the epoxy. Further, it is described that the active species of the polymerization initiator may be any of radicals, cations, and anions.

  On the other hand, quantum dots tend to aggregate in the composition or in a resin obtained by curing the composition, resulting in a decrease in luminous efficiency. For this reason, the dispersibility of the quantum dot in the composition or resin is improved by coordinating the ligand for improving the dispersibility on the surface of the quantum dot.

Special table 2013-544018 gazette JP 2010-229216 A

However, in addition polymerization of an epoxy monomer and an amine, it is difficult to uniformly mix equimolar amounts, and there is a concern that physical properties such as the strength of the wavelength conversion layer may be lowered due to residual unreacted monomers.
On the other hand, when a composition comprising a quantum dot coordinated with a ligand, a polymerizable compound, and a polymerization initiator is formed on a coating film and then cured by cationic polymerization, curing may not proceed sufficiently. It was. A display device incorporating such a wavelength conversion member containing an uncured product has a problem of low brightness. This is considered to be because oxygen is easily taken in when there are many uncured products.

  As a result of intensive studies by the present inventors, it has been found that there is a high correlation between the molar ratio of the cationic polymerization initiator to the ligand and the polymerization reaction rate. In particular, in the quantitative reaction, a polymerization initiator of about 2 times the molar equivalent or more with respect to the ligand is required. This led to the view that the polymerization was inhibited by using the active species of the polymerization initiator not in the polymerization reaction but in the reaction with the ligand peeled from the quantum dot. Therefore, as a solution, it is conceivable to increase the amount of the polymerization initiator. However, if the amount of the polymerization initiator is increased, the polymerization reaction rate is increased, but there is a concern that physical properties such as the strength and oxygen permeability of the wavelength conversion layer are deteriorated.

The present invention has been made in view of the above circumstances, and is a composition containing quantum dots coordinated with a ligand, which provides a composition for a wavelength conversion layer having a high polymerization reaction rate and good curability. It is intended to do.
The present invention also provides a wavelength conversion member having a wavelength conversion layer obtained by curing a composition for wavelength conversion layer having a high polymerization reaction rate and good curability, and a backlight unit having a high luminance provided with the wavelength conversion member. An object of the present invention is to provide a liquid crystal display device.

The wavelength conversion layer composition of the present invention is
Quantum dots that are excited by excitation light to emit fluorescence;
A ligand having a Lewis basic coordinating group coordinated on the surface of the quantum dot;
An anionic polymerizable compound;
An anionic polymerization initiator.

  The ligand is preferably a phosphine compound, an amine compound and a thiol compound.

  The base generated from the anionic polymerization initiator is preferably an amine, imidazole, amidine, or guanidine.

  The anionic polymerizable compound is preferably a compound having at least one functional group selected from an epoxy group and an oxetanyl group.

  Anionic polymerization initiators include cyclohexylammonium 2- (3-benzoylphenyl) propionate, 1,2-dicyclohexyl-4,4,5,5-tetramethylbiguanidinium n-butyltriphenylborate, 1,2-diisopropyl- It is preferably a salt of 3- [bis (dimethylamino) methylene] guanidinium 2- (3-benzoylphenyl) propionate or 1,8-diazabicyclo [5.4.0] undecene-7 and octylic acid.

  The addition amount of the anionic polymerization initiator is preferably 0.1 parts by mass or more and 10.0 parts by mass or less with respect to 100 parts by mass of the anionic polymerizable compound.

  The wavelength conversion member of the present invention is obtained by curing the wavelength conversion layer composition of the present invention.

The backlight unit of the present invention is
A light source that emits primary light;
A wavelength conversion member of the present invention provided on a light source;
A retroreflective member disposed opposite the light source across the wavelength conversion member;
A backlight unit provided with a reflection plate disposed opposite to the wavelength conversion member across the light source,
The wavelength conversion member emits fluorescence using at least a part of the primary light emitted from the light source as excitation light, and emits at least light including secondary light made of fluorescence.

The liquid crystal display device of the present invention comprises the backlight unit of the present invention,
And a liquid crystal cell disposed opposite to the retroreflective member side of the backlight unit.

The composition for wavelength conversion layer of the present invention comprises a quantum dot excited by excitation light to emit fluorescence, a ligand having a Lewis basic coordinating group coordinated on the surface of the quantum dot, an anion It contains a polymerizable compound and an anionic polymerization initiator. By having such a configuration, the active species generated from the anionic polymerization initiator is the same basic as the coordination group of the ligand, so that the polymerization reaction proceeds well without deactivating the active species. Therefore, the polymerization reaction rate is high and curability is good.
Moreover, since the backlight unit and the liquid crystal display device of the present invention include a sufficiently cured wavelength conversion member, the uncured portion can be prevented from taking in oxygen, and thus has high luminance.

It is a schematic structure section showing a wavelength conversion member which is one embodiment of the present invention. It is a schematic block diagram which shows an example of the manufacturing apparatus of a wavelength conversion member. It is the elements on larger scale of the manufacturing apparatus shown in FIG. It is a schematic structure sectional view of a backlight unit provided with a wavelength conversion member which is one embodiment of the present invention. It is a schematic structure sectional view showing a liquid crystal display provided with the backlight unit of the present invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. The following description may be made based on representative embodiments of the present invention, but the present invention is not limited to such embodiments.
In the present specification, a numerical range represented by using “to” means a range including numerical values described before and after “to” as a lower limit value and an upper limit value. Further, in this specification, the “half-value width” of a peak refers to the width of the peak at a peak height of ½. In addition, light having an emission center wavelength in the wavelength band of 430 to 480 nm is called blue light, light having an emission center wavelength in the wavelength band of 520 to 560 nm is called green light, and the emission center wavelength is in the wavelength band of 600 to 680 nm. The light having a color is called red light. The (meth) acryloyl group means one or both of an acryloyl group and a methacryloyl group.

[Composition for wavelength conversion layer]
Hereinafter, the detail of the composition for wavelength conversion layers is demonstrated.

(Quantum dot)
The quantum dots emit fluorescence when excited by excitation light. The composition for wavelength conversion layers may contain 2 or more types of quantum dots from which the light emission characteristic differs as a quantum dot. In the case of using the blue light as the excitation light, the wavelength conversion layer composition is excited by being excited by the blue light L _B fluorescent quantum dots emits (red light) L _R, and the blue light L _B It may contain quantum dots to emit fluorescence (green light) L _G.
In the case of using ultraviolet light as excitation light, the wavelength conversion layer composition is excited by the ultraviolet light L _UV fluorescent quantum dots that emit (red light) L _R, it is excited by the ultraviolet light L _UV can be fluorescence is excited by the quantum dots, and the ultraviolet light L _UV emits (green light) L _G containing quantum dots to emit fluorescence (blue light) L _B.

The quantum dots that emit red light _{L R,} may be mentioned those having an emission center wavelength in a wavelength range of 600～680Nm. The quantum dot emits green light _{L G,} it may be mentioned those having an emission center wavelength in a wavelength range of 520～560Nm. The quantum dot emitting blue light _{L B,} may include those having an emission center wavelength in a wavelength range of 430 to 480 nm.

  Regarding the quantum dots, for example, paragraphs 0060 to 0066 of JP2012-169271A can be referred to, but the quantum dots are not limited to those described in this publication.

  As the quantum dots, for example, core-shell type semiconductor nanoparticles are preferable from the viewpoint of improving durability. As the core, II-VI group semiconductor nanoparticles, III-V group semiconductor nanoparticles, multi-component semiconductor nanoparticles, and the like can be used. Specific examples include CdSe, CdTe, CdS, ZnS, ZnSe, ZnTe, InP, InAs, and InGaP, but are not limited thereto. Among these, CdSe, CdTe, InP, and InGaP are preferable from the viewpoint of emitting visible light with high efficiency. As the shell, CdS, ZnS, ZnO, GaAs, and a composite thereof can be used, but the shell is not limited thereto. The emission wavelength of the quantum dots can usually be adjusted by the composition and size of the particles.

-Ligand and coordinating group-
The ligand according to the present invention has a Lewis basic coordinating group that coordinates to the surface of a quantum dot. Examples of Lewis basic coordinating groups include amino groups, phosphine groups, and phosphine oxide groups. Examples of the ligand include phosphine compounds, amine compounds, and thiol compounds. Specifically, hexylamine, decylamine, hexadecylamine (HDA), octadecylamine, oleylamine, myristylamine, laurylamine, trioctylphosphine, and trioctylphosphine oxide (TOPO), 2-mercaptoethanol, 1-thioglycerol , 3-mercaptopropionic acid and the like. Of these, hexadecylamine, trioctylphosphine, and trioctylphosphine oxide are preferable, and trioctylphosphine and trioctylphosphine oxide are particularly preferable.

A quantum dot coordinated with these ligands can be produced by a known synthesis method. For example, C.I. B. Murray, D.M. J. et al. Norris, M.M. G. It can be synthesized by the method described in Bawendi, Journal American Chemical Society, 1993, 115 (19), pp 8706-8715, or The Journal Physical Chemistry, 101, pp 9463-9475, 1997. Moreover, the quantum dot which the ligand coordinated can use a commercially available thing without a restriction | limiting at all. For example, Lumidot ^™ (manufactured by Sigma Aldrich) can be mentioned.

  In the composition for wavelength conversion layer, the content of the quantum dot coordinated with the ligand is preferably 0.01 to 10% by mass with respect to the total mass of the anionic polymerizable compound contained in the composition for wavelength conversion layer, 0.05-5 mass% is more preferable.

  The quantum dots of the present invention may be added to the wavelength conversion layer composition in the form of particles, or may be added in the form of a dispersion dispersed in a solvent. The addition in the state of a dispersion is preferable from the viewpoint of suppressing the aggregation of the quantum dot particles.

(Anionic polymerizable compound)
As the anionic polymerizable compound, a compound having at least one functional group selected from an epoxy group and an oxetanyl group, an acrylic compound, or a vinyl compound can be used. More preferably, it is a compound having at least one functional group selected from an epoxy group and an oxetanyl group. Specific examples are given below.

-Compound having at least one functional group selected from epoxy groups-
Examples of the compound having at least one functional group selected from epoxy groups include bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, bisphenol S diglycidyl ether, brominated bisphenol A diglycidyl ether, brominated bisphenol F di Glycidyl ether, brominated bisphenol S diglycidyl ether, hydrogenated bisphenol A diglycidyl ether, hydrogenated bisphenol F diglycidyl ether, hydrogenated bisphenol S diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-hexane Diol diglycidyl ether, glycerin triglycidyl ether, trimethylolpropane triglycidyl ether, dicyclopentadiene dimethanol diglycidyl ether , Polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ethers; polyether polyols obtained by adding one or more alkylene oxides to aliphatic polyhydric alcohols such as ethylene glycol, propylene glycol and glycerin Glycidyl ethers; diglycidyl esters of aliphatic long-chain dibasic acids; glycidyl esters of higher fatty acids; compounds containing epoxycycloalkanes and the like are preferably used in the present invention.

  Commercially available products that can be suitably used as a compound having at least one functional group selected from epoxy groups include bisphenol A diglycidyl ether, hydrogenated bisphenol A diglycidyl ether, dicyclopentadiene dimethanol diglycidyl ether, and the like. . These can be used alone or in combination of two or more.

  Moreover, although the manufacturing method of the compound which has at least one functional group selected from an epoxy group is not ask | required, For example, Maruzen KK publication, 4th edition experimental chemistry course 20 organic synthesis II, 213, 1992, Ed. By Alfred Hasfner, The Chemistry of Heterocyclic compounds, Vol. 30, Advertisement, Small Ring Heterocycles part3, Oxilanes, John & Wiley and Sons, Anc No. 5, 42, 1986, Yoshimura, Adhesion, Vol. 30, No. 7, 42, 1986, Japanese Patent Application Laid-Open No. 11-100308, Japanese Patent No. 2906245, Japanese Patent No. 2926262, and the like.

-Alicyclic epoxy compound-
The anionic polymerizable compound may be an alicyclic epoxy compound. The alicyclic epoxy compound may be one kind or two or more kinds having different structures. In addition, below, content regarding an alicyclic epoxy compound shall mean these total content, when using 2 or more types of alicyclic epoxy compounds from which a structure differs. This also applies to other components when two or more types having different structures are used. As described above, the alicyclic epoxy compound has better curability by light irradiation than the aliphatic epoxy compound. The use of a polymerizable compound having excellent photocurability is advantageous in that, in addition to improving productivity, a layer having uniform physical properties can be formed on the light irradiation side and the non-irradiation side. As a result, curling of the wavelength conversion layer can be suppressed and a wavelength conversion member with uniform quality can be provided. In general, epoxy compounds also tend to have less cure shrinkage during photocuring. This is advantageous in forming a smooth wavelength conversion layer with little deformation.

  The alicyclic epoxy compound has at least one alicyclic epoxy group. Here, the alicyclic epoxy group means a monovalent substituent having a condensed ring of an epoxy ring and a saturated hydrocarbon ring, preferably a monovalent substituent having a condensed ring of an epoxy ring and a cycloalkane ring. It is. More preferable alicyclic epoxy compounds include those having one or more of the following structures in which one epoxy ring and one cyclohexane ring are condensed.

  Two or more structures may be contained in one molecule, and preferably one or two in one molecule. In addition, the above structure may have one or more substituents. Examples of the substituent include an alkyl group, a hydroxyl group, an alkoxy group, a halogen atom, a cyano group, an amino group, a nitro group, an acyl group, and a carboxyl group. As an alkyl group, a C1-C6 alkyl group can be mentioned, for example. As an alkoxy group, a C1-C6 alkoxy group can be mentioned, for example. As a halogen atom, a fluorine atom, a chlorine atom, or a bromine atom can be mentioned, for example.

  The alicyclic epoxy compound may have a polymerizable functional group other than the alicyclic epoxy group. The polymerizable functional group refers to a functional group capable of causing a polymerization reaction by radical polymerization or anionic polymerization, and examples thereof include a (meth) acryloyl group.

Examples of commercially available products that can be suitably used as the alicyclic epoxy compound include Daicel Corporation's Celoxide 2000, Celoxide 2021P, Celoxide 3000, Celoxide 8000, Cyclomer M100, Epolide GT301, Epolide GT401, and 4-vinylcyclohexene manufactured by Sigma-Aldrich. Dioxide, Nippon Terpene Chemical Co., Ltd. D-limonene oxide, Shin Nippon Rika Co., Ltd. sunsizer E-PS, etc. can be mentioned. These can be used individually by 1 type or in combination of 2 or more types. Among these, from the viewpoint of improving the adhesion between the wavelength conversion layer and the adjacent layer, the following alicyclic epoxy compound A or B is particularly preferable. The alicyclic epoxy compound A is commercially available as Daicel Corporation's Celoxide 2021P. The alicyclic epoxy compound B can be obtained as a commercial product Daicel Corporation's Cyclomer M100.
“Cyclomer” is a registered trademark of Daicel Corporation. It is a registered trademark of Shin Nippon Rika Co., Ltd.

  Moreover, an alicyclic epoxy compound can also be manufactured by a well-known synthesis method. The synthesis method can be synthesized with reference to the same literature as the above-mentioned epoxy compound.

-Compound having oxetanyl group-
4,4′-bis [(3-ethyl-3-oxetanyl) methoxymethyl] biphenyl, 1,4-benzenedicarboxylic acid bis [(3-ethyl-3-oxetanyl) methyl] ester, 1,4-bis [( 3-ethyl-3-oxetanyl) methoxymethyl] benzene and the like xylylene oxetane, 3-ethyl-3-(((3-ethyloxetane-3-yl) methoxy) methyl) oxetane, 2-ethylhexyloxetane, 3-ethylhexyl Examples thereof include oxetane, 3-ethyl-3-hydroxyoxetane, 3-ethyl-3-hydroxymethyloxetane, or oxetaneated phenol novolak. Commercially available products include 3-ethyl-3-oxetanemethanol (TMPO, Tokyo Chemical Industry Co., Ltd.), 3-ethyl-3 {[(3-ethyloxetane-3-yl) methoxy] methyl} oxetane (trade name “ OXT-221 ", Toagosei Co., Ltd.).

-Acrylic compounds-
The anionic polymerizable compound may be an acrylic compound. A monofunctional or polyfunctional (meth) acrylate monomer is preferable, and a monomer prepolymer or polymer may be used as long as it has polymerizability. In the present specification, “(meth) acrylate” means one or both of acrylate and methacrylate.

  Monofunctional (meth) acrylate monomers include acrylic acid and methacrylic acid, derivatives thereof, and more specifically, monomers having one polymerizable unsaturated bond ((meth) acryloyl group) of (meth) acrylic acid in the molecule. Can be mentioned. As specific examples, methyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isononyl (meth) acrylate, n-octyl (meth) acrylate, lauryl (meth) Examples thereof include alkyl (meth) acrylates having 1 to 30 carbon atoms, such as acrylate and stearyl (meth) acrylate, and 2-cyanoacrylates.

Examples of the bifunctional (meth) acrylate monomer include neopentyl glycol di (meth) acrylate, 1,9-nonanediol di (meth) acrylate, and dipropylene glycol di (meth) acrylate.
Trifunctional (meth) acrylate monomers can include ECH-modified glycerol tri (meth) acrylate, EO-modified glycerol tri (meth) acrylate, and PO-modified glycerol tri (meth) acrylate.

  Among these, 2-cyanoacrylates represented by the following general formula C are more preferable.

  R represents a hydrogen atom, a linear or branched alkyl group having 1 to 6 carbon atoms (for example, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, iso-amyl). , Hexyl, isopentyl, tert-pentyl, neopentyl, hexyl, and isohexyl), cyclic aliphatic groups having 5 to 10 carbon atoms (for example, cyclopentyl, cyclohexyl, cyclopeptyl, and adamantyl), or carbon. A number 6 to 20 aromatic group (for example, phenyl, benzyl, and naphthyl are included). R may further have at least one of a halogen atom, an ether bond, a hydroxy group, an amide group, and an ester group.

-Vinyl compounds-
The anionic polymerizable compound may be a vinyl compound. Examples of vinyl compounds include vinylidene cyanide and nitroethylene.

  Further, the total amount of the anionic polymerizable compound in the composition for wavelength conversion layer is 50 to 99 parts by mass with respect to 100 parts by mass of the composition for wavelength conversion layer from the viewpoint of maintaining curability and handling the composition. It is preferably 70 to 97 parts by mass.

(Anionic polymerization initiator)
The anionic polymerization initiator is not particularly limited, and a conventionally known photobase generator can be used. For example, carbamate derivatives, amide derivatives, carboxylates, and borate salts exhibiting photodegradability can be mentioned. Examples of the base to be generated include primary amines, secondary amines, tertiary amines, imidazoles, amidines, and guanidines. Preferred are strong bases such as tertiary amines, imidazoles, amidines, and guanidines. . More preferred are super strong bases such as amidine and guanidine. These compounds have high reactivity and are preferable from the viewpoint of polymerization rate.

  A compound represented by the following general formula D is preferred as the amine.

R ¹ , R ² , and R ³ are each independently a hydrogen atom, a linear or branched alkyl group having 1 to 12 carbon atoms (eg, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec- Butyl, tert-butyl, pentyl, iso-amyl, hexyl, isopentyl, tert-pentyl, neopentyl, hexyl, isohexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, and 2-ethylhexyl). It represents a 5-10 cycloaliphatic group (for example, cyclopentyl, cyclohexyl, cyclopeptyl, and adamantyl), and a C6-C20 aromatic group (for example, phenyl, benzyl, and naphthyl). Furthermore, you may have a halogen atom, an ether bond, a hydroxyl group, an amide group, and an ester group.

The amine may have a cyclic structure in which R ² and R ³ are bonded to each other. For example, the compound represented by the following general formula (D-1) and (D-2) can be mentioned.

  Examples of imidazole include compounds represented by the following general formula E.

R ¹ , R ² , R ³ , and R ⁴ are each independently a hydrogen atom, a halogen atom, a linear or branched alkyl group having 1 to 12 carbon atoms (for example, methyl, ethyl, propyl, isopropyl, Butyl, isobutyl, sec-butyl, tert-butyl, pentyl, iso-amyl, hexyl, isopentyl, tert-pentyl, neopentyl, hexyl, isohexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, 2-ethylhexyl), carbon A C5-C10 cyclic aliphatic group (for example, cyclopentyl, cyclohexyl, cyclopeptyl, adamantyl) and a C6-C20 aromatic group (for example, phenyl, benzyl, naphthyl) are represented. Further, each group may have a halogen atom, an ether bond, a hydroxy group, an amide group, or an ester group.

  Examples of the amidine include compounds represented by the following general formula F.

R ¹ , R ² , R ³ , and R ⁴ have the same meaning as R ¹ described above, and the preferred range is also the same.

The amidine may have a cyclic structure in which R ² and R ³ , and R ³ and R ⁴ are bonded to each other. For example, the following compounds (F-1) and (F-2) can be mentioned.
An example is shown below.

  Examples of guanidine include compounds represented by the following general formula G.

R ¹ , R ² , R ³ , R ⁴ , and R ⁵ have the same meanings as R ¹ described above, and the preferred ranges are also the same.

Guanidine may have a cyclic structure in which R ² and R ³ , R ⁴ and R ⁵ are bonded to each other. For example, the compound represented by the following general formula (G-1) can be given.

  Commercially available products that can be suitably used as the photobase generator include WPBG-082 (guanidinium 2- (3-benzoylphenyl) propionate) and WPBG-168 (cyclohexylammonium 2- (3-benzoyl) manufactured by Wako Pure Chemical Industries, Ltd. Phenyl) propionate), WPBG-266 (1,2-diisopropyl-3- [bis (dimethylamino) methylene] guanidium 2- (3-benzoylphenyl) propionate), WPBG-300 (1,2-dicyclohexyl-4,4) , 5,5-tetramethylbiguanidinium n-butyltriphenylborate), 2- (9-oxoxanthen-2-yl) propionic acid 1,5,7-triazabicyclo [4] from Tokyo Chemical Industry Co., Ltd. 4.0] dec-5-ene, acetophenone o-benzoyloxime, And the like can be given Fejipin. Among these, WPBG-266, WPBG-300, and WPBG-168 are preferable, and WPBG-266 and WPBG-300 that generate a strong base are more preferable. These can be used individually by 1 type or in combination of 2 or more types.

  The anionic polymerization initiator may be a thermal base generator. Examples of the heat generating base include carbamate derivatives such as 1-methyl-1- (4-biphenylyl) ethyl carbamate and 1,1-dimethyl-2-cyanoethyl carbamate, urea, N, N-dimethyl-N′-methyl urea, and the like. Urea derivatives, dihydropyridine derivatives such as 1,4-dihydronicotinamide, quaternized ammonium salts of organic silanes and organic boranes, potassium trichloroacetate, potassium phenylpropiolate, cesium phenylpropiolate, and inorganic acids and inorganic alkali metals Organic acids such as salts, phenol, octylic acid, p-toluenesulfonic acid, formic acid and 1,8-diazabicyclo [5.4.0] undecene-7 and 1,5-diazabicyclo [4.3.0] nonene-5 And a salt made of amidine.

  Examples of commercially available products that can be suitably used as a thermal base generator include U-CAT SA-1 (1,8-diazabicyclo [5.4.0] undecene-7 and phenol salt) from San Apro Co., Ltd., U-CAT. SA-102 (1,8-diazabicyclo [5.4.0] undecene-7 and octylic acid salt). These can be used individually by 1 type or in combination of 2 or more types.

  The anionic polymerization initiator is preferably 0.1 parts by mass or more and 10.0 parts by mass or less, and 0.5 parts by mass or more with respect to 100 parts by mass of the anionic polymerizable compound contained in the composition for wavelength conversion layer. It is more preferably 10 parts by mass or less, further preferably 0.5 parts by mass or more and 6 parts by mass or less, and particularly preferably 0.5 parts by mass or more and 3 parts by mass or less. Use of an appropriate amount of the polymerization initiator is preferable from the viewpoint of reducing the amount of light irradiation for curing and uniformly curing the entire wavelength conversion layer.

(Radically polymerizable compound)
The composition for wavelength conversion layers may contain a radically polymerizable compound as needed. They can be adjusted by adding radically polymerizable compounds. The content of the radical polymerizable compound in the wavelength conversion layer composition is preferably about 0 to 30 parts by mass. As an example of a preferable radical polymerizable compound, the above-mentioned acrylic compound can be mentioned.

(Radical polymerization initiator)
The radical polymerization initiator is not particularly limited, and a conventionally known radical initiator can be used. JP, 2013-043382, A paragraph 0037 can be referred to for a radical polymerization initiator, for example. The polymerization initiator is preferably 0.1 parts by mass or more, more preferably 0.5 to 5 parts by mass, based on the total mass of the radical polymerizable compound contained in the wavelength conversion layer composition.

(Other additives)
The composition for wavelength conversion layers of this invention may contain a viscosity modifier, a solvent, and a silane coupling agent.

-Viscosity modifier-
The composition for wavelength conversion layers may contain a viscosity modifier as needed. They can be adjusted to the desired viscosity by adding viscosity modifiers. The viscosity modifier is preferably a filler having a particle size of 5 nm to 300 nm. The viscosity modifier may be a thixotropic agent. In the present invention and the present specification, the thixotropic property refers to the property of reducing the viscosity with respect to the increase in shear rate in the liquid composition, and the thixotropic agent includes the liquid composition by including it. It refers to a material having a function of imparting thixotropic properties to the composition. Specific examples of thixotropic agents include fumed silica, alumina, silicon nitride, titanium dioxide, calcium carbonate, zinc oxide, talc, mica, feldspar, kaolinite (kaolin clay), pyrophyllite (waxite clay), and sericite. (Sericite), bentonite, smectite vermiculites (montmorillonite, beidellite, nontronite, saponite, etc.), organic bentonite, organic smectite and the like.

-Solvent-
The composition for wavelength conversion layers may contain a solvent as needed. In this case, the type and amount of the solvent used are suitable for anionic polymerization. Solvents include, for example, aromatic hydrocarbons such as toluene and xylene, alcohols such as methanol, ethanol, butanol, isopropyl alcohol, ethylene glycol and propylene glycol, esters such as ethyl acetate and butyl acetate, ketones such as acetone and methyl ethyl ketone, tetrahydrofuran And cyclic ethers such as 1,4-dioxane. The addition amount is preferably 0 to 500 parts by mass or less with respect to 100 parts by mass of the composition for wavelength conversion layer from the viewpoint of coating viscosity adjustment and film thickness control. The organic solvent can be used alone or in combination of two or more.

-Silane coupling agent-
The composition may further contain a silane coupling agent. Since the wavelength conversion layer formed from the polymerizable composition containing the silane coupling agent becomes stronger in adhesion to the adjacent layer by the silane coupling agent, it can exhibit even more excellent light resistance. . This is mainly due to the fact that the silane coupling agent contained in the wavelength conversion layer forms a covalent bond with the surface of the adjacent layer and the constituent components of the layer by hydrolysis reaction or condensation reaction. At this time, it is also preferable to provide an inorganic layer described later as an adjacent layer. In addition, when the silane coupling agent has a reactive functional group such as a radical polymerizable group, a monomer component constituting the wavelength conversion layer and a cross-linked structure can also be formed, thereby improving the adhesion between the wavelength conversion layer and the adjacent layer. Can contribute. In addition, in this specification, the silane coupling agent contained in the wavelength conversion layer is meant to include the silane coupling agent in the form after the reaction as described above.

  As the silane coupling agent, a known silane coupling agent can be used without any limitation. As a preferable silane coupling agent from the viewpoint of adhesion, a silane coupling agent represented by the general formula (1) described in JP2013-43382A can be exemplified. For details, the description of paragraphs 0011 to 0016 of JP2013-43382A can be referred to. The amount of the additive such as a silane coupling agent is not particularly limited and can be set as appropriate.

  The preparation method of the composition for wavelength conversion layers is not restrict | limited, What is necessary is just to implement by the preparation procedure of a general polymeric composition.

  Next, a wavelength conversion member and a backlight unit including the same according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view of the wavelength conversion member of the present embodiment.

[Wavelength conversion member]
As shown in FIG. 1, the wavelength conversion member 1 </ b> D of the present embodiment has barrier films 10 and 20 disposed on both main surfaces of the wavelength conversion layer 30 and the wavelength conversion layer 30 obtained by curing the composition for wavelength conversion layer. With. Here, the “main surface” refers to the surface (front surface, back surface) of the wavelength conversion layer disposed on the viewing side or the backlight side when the wavelength conversion member is used in a display device described later. The same applies to the main surfaces of the other layers and members. Each of the barrier films 10 and 20 includes the barrier layers 12 and 22 and the supports 11 and 21 from the wavelength conversion layer 30 side, respectively. Hereinafter, the details of the wavelength conversion layer 30, the barrier films 10 and 20, the supports 11 and 21, and the barrier layers 12 and 22 will be described.

(Wavelength conversion layer)
Wavelength converting layer 30, as shown in FIG. 1, it is excited by being excited by the blue light L _B fluorescent quantum dots 30A emits (red light) L _R, and the blue light L _B in the organic matrix 30P fluorescence quantum dots 30B for emitting (green light) _{L G} is dispersed. In FIG. 1, the quantum dots 30 </ b> A and 30 </ b> B are greatly illustrated for easy visual recognition. It is a range.
A ligand having a Lewis basic coordinating group is coordinated on the surfaces of the quantum dots 30A and 30B. The wavelength conversion layer 30 is a composition for a wavelength conversion layer containing quantum dots 30A and 30B coordinated with a ligand, an anion polymerizable compound, and an anion polymerization initiator, generating a base by light irradiation or heat to generate an anion. It is cured by polymerization.
The organic matrix 30P is formed by curing an anionic polymerizable compound by anionic polymerization.

  The thickness of the wavelength conversion layer 30 is preferably in the range of 1 to 500 μm, more preferably in the range of 10 to 250 μm, and still more preferably in the range of 30 to 150 μm. A thickness of 1 μm or more is preferable because a high wavelength conversion effect can be obtained. Further, it is preferable that the thickness is 500 μm or less because the backlight unit can be thinned when incorporated in the backlight unit.

In the above embodiment has been described manner using the blue light as the light source, the wavelength converting layer 30, the quantum dots 30A that emits ultraviolet light L _UV by being excited fluorescence (red light) L _R in an organic matrix 30P When, by being excited by the ultraviolet light _{L UV} fluorescent quantum dots 30C for emitting quantum dots 30B for emitting (green light) _{L G,} after being excited by the ultraviolet light _{L UV} fluorescent (blue light) _{L B} (not shown) May be dispersed. The shape of the wavelength conversion layer is not particularly limited, and can be an arbitrary shape.

(Barrier film)
The barrier films 10 and 20 are films having a gas barrier function for blocking oxygen. In this embodiment, the barrier layers 12 and 22 are provided on the supports 11 and 21, respectively. Due to the presence of the supports 11 and 21, the strength of the wavelength conversion member 1D is improved, and each layer can be easily formed.
In the present embodiment, the barrier films 10 and 20 in which the barrier layers 12 and 22 are supported by the supports 11 and 21 are shown. However, the barrier layers 12 and 22 are not supported by the supports 11 and 21. Also good. In the present embodiment, the wavelength conversion member in which the barrier layers 12 and 22 are provided adjacent to both main surfaces of the wavelength conversion layer 30 is shown. However, the supports 11 and 21 have sufficient barrier properties. When it exists, you may form a barrier layer only by the support bodies 11 and 21. FIG.

  Moreover, although the aspect in which two barrier films 10 and 20 are contained in a wavelength conversion member like this embodiment is preferable, the aspect contained only one may be sufficient.

  The barrier films 10 and 20 preferably have a total light transmittance of 80% or more in the visible light region, and more preferably 90% or more. The visible light region refers to a wavelength region of 380 to 780 nm, and the total light transmittance indicates an average value of light transmittance over the visible light region.

The oxygen permeability of the barrier films 10 and 20 is preferably 1.00 cm ³ / (m ² · day · atm) or less. Here, the oxygen permeability was measured using an oxygen gas permeability measuring device (trade name “OX-TRAN 2/20”, manufactured by MOCON) under the conditions of a measurement temperature of 23 ° C. and a relative humidity of 90%. Value. The oxygen permeability of the barrier films 10 and 20 is more preferably 0.10 cm ³ / (m ² · day · atm) or less, and still more preferably 0.01 cm ³ / (m ² · day · atm) or less. . The oxygen permeability 1.00 cm ³ / (m ² · day · atm) is 1.14 × 10 ⁻¹ fm / Pa · s when converted to an SI unit system.

(Support)
In the wavelength conversion member 1D, at least one main surface of the wavelength conversion layer 30 is supported by the support 11 or 21. As for this wavelength conversion layer 30, it is preferable that the main surfaces of the front and back of the wavelength conversion layer 30 are supported by the support bodies 11 and 21 like this embodiment.

  The average film thickness of the supports 11 and 21 is preferably 10 μm or more and 500 μm or less, more preferably 20 μm or more and 400 μm or less, and more preferably 30 μm or more and 300 μm or less from the viewpoint of impact resistance of the wavelength conversion member. It is preferable. In an aspect in which retroreflection of light is increased, such as when the concentration of the quantum dots 30A and 30B included in the wavelength conversion layer 30 is reduced, or when the thickness of the wavelength conversion layer 30 is reduced, absorption of light having a wavelength of 450 nm is performed. Since the rate is preferably lower, the average film thickness of the supports 11 and 21 is preferably 40 μm or less, and more preferably 25 μm or less from the viewpoint of suppressing a decrease in luminance.

In order to further reduce the concentration of the quantum dots 30A and 30B included in the wavelength conversion layer 30, or to further reduce the thickness of the wavelength conversion layer 30, retroreflection of a backlight unit described later to maintain the display color of the LCD. It is necessary to increase the number of times the excitation light passes through the wavelength conversion layer by providing means for increasing the retroreflection of light, such as providing a plurality of prism sheets on the active member. Therefore, the support is preferably a transparent support that is transparent to visible light.
Here, being transparent to visible light means that the light transmittance in the visible light region is 80% or more, preferably 85% or more. The light transmittance used as a measure of transparency is measured by measuring the total light transmittance and the amount of scattered light using the method described in JIS-K7105, that is, using an integrating sphere type light transmittance measuring device. It can be calculated by subtracting the rate. Regarding the support, paragraphs 0046 to 0052 of JP-A-2007-290369 and paragraphs 0040 to 0055 of JP-A-2005-096108 can be referred to.

The supports 11 and 21 preferably have an in-plane retardation Re (589) at a wavelength of 589 nm of 1000 nm or less. More preferably, it is 500 nm or less, and further preferably 200 nm or less.
After the wavelength conversion member 1D is manufactured, when inspecting for the presence of foreign matter or defects, two polarizing plates are placed in the extinction position, and the wavelength conversion member is inserted between them for observation, making it easy to find foreign matters and defects. . It is preferable that the Re (589) of the support is in the above range because foreign matters and defects can be more easily found during inspection using a polarizing plate.
Here, Re (589) is measured by making light having a wavelength of 589 nm incident in the normal direction of the film in KOBRA-21ADH or KOBRA WR (manufactured by Oji Scientific Instruments). In selecting the measurement wavelength λnm, the wavelength selection filter can be exchanged manually, or the measurement value can be converted by a program or the like.

  The supports 11 and 21 are preferably supports having a barrier property against oxygen and moisture. Preferred examples of the support include a polyethylene terephthalate film, a film made of a polymer having a cyclic olefin structure, and a polystyrene film.

(Barrier layer)
The barrier layers 12 and 22 are respectively provided with organic layers 12a and 22a and inorganic layers 12b and 22b in this order from the supports 11 and 21 side. The organic layers 12 a and 22 a may be provided between the inorganic layers 12 b and 22 b and the wavelength conversion layer 30.

  The barrier layers 12 and 22 are formed by being formed on the surfaces of the supports 11 and 21. Therefore, the barrier films 10 and 20 are comprised by the support bodies 11 and 21 and the barrier layers 12 and 22 provided on it. In the case where the barrier layers 12 and 22 are provided, the support preferably has high heat resistance. In the wavelength conversion member 1D, the layer in the barrier films 10 and 20 adjacent to the wavelength conversion layer 30 may be an inorganic layer or an organic layer, and is not particularly limited.

  The barrier layers 12 and 22 are preferably composed of a plurality of layers because the barrier property can be further enhanced. Therefore, the barrier layers 12 and 22 are preferable from the viewpoint of improving light resistance. However, as the number of layers increases, the light transmission of the wavelength conversion member increases. Since the rate tends to decrease, it is preferable to design in consideration of good light transmittance and barrier properties.

-Inorganic layer-
The inorganic layer is a layer mainly composed of an inorganic material, and is preferably a layer in which the inorganic material occupies 50% by mass or more, more preferably 80% by mass or more, and particularly 90% by mass or more, and is a layer formed only from the inorganic material. Is most preferred. The inorganic layers 12b and 22b suitable for the barrier layers 12 and 22 are not particularly limited, and various inorganic compounds such as metals, inorganic oxides, nitrides, and oxynitrides can be used. As an element constituting the inorganic material, silicon, aluminum, magnesium, titanium, tin, indium and cerium are preferable, and one or more of these may be included. Specific examples of the inorganic compound include silicon oxide, silicon oxynitride, aluminum oxide, magnesium oxide, titanium oxide, tin oxide, indium oxide alloy, silicon nitride, aluminum nitride, and titanium nitride. As the inorganic layer, a metal film such as an aluminum film, a silver film, a tin film, a chromium film, a nickel film, or a titanium film may be provided.

Among the above materials, an inorganic layer containing silicon oxide, silicon nitride, silicon oxynitride, silicon carbide, or aluminum oxide is particularly preferable. Since the inorganic layer made of these materials has good adhesion to the organic layer, even when the inorganic layer has pinholes, the organic layer can effectively fill the pinholes, and the barrier property is further improved. It can be made even higher.
Further, silicon nitride is most preferable from the viewpoint of suppressing light absorption in the barrier layer.

  A method for forming the inorganic layer is not particularly limited, and various film forming methods that can evaporate or scatter the film forming material and deposit it on the deposition surface can be used.

  Examples of the method for forming the inorganic layer include a vacuum evaporation method in which an inorganic material such as an inorganic oxide, an inorganic nitride, an inorganic oxynitride, or a metal is heated and evaporated; an inorganic material is used as a raw material, and oxygen gas is introduced. Oxidation reaction vapor deposition method for oxidizing and vapor deposition; sputtering method using inorganic material as target raw material, introducing argon gas and oxygen gas and performing sputtering; plasma generated on inorganic material with plasma gun When chemical vapor deposition (physical vapor deposition method, PVD method) such as ion plating, which is heated by a beam for vapor deposition, or a silicon oxide vapor deposition film is formed, a plasma chemical vapor phase using an organosilicon compound as a raw material Growth method (Chemical Vapor Deposition method, CVD method) Etc. The.

  The thickness of the inorganic layer may be 1 nm to 500 nm, preferably 5 nm to 300 nm, and more preferably 10 nm to 150 nm. When the film thickness of the adjacent inorganic layer is within the above-described range, it is possible to suppress absorption of light in the inorganic layer while realizing good barrier properties, and provide a wavelength conversion member with higher light transmittance. Because it can be done.

-Organic layer-
The organic layer is a layer containing an organic material as a main component, and is preferably a layer that occupies 50% by mass or more, further 80% by mass or more, and particularly 90% by mass or more. As the organic layer, paragraphs 0020 to 0042 of JP-A-2007-290369 and paragraphs 0074 to 0105 of JP-A-2005-096108 can be referred to. The organic layer preferably contains a cardo polymer. This is because the adhesion between the organic layer and the adjacent layer, particularly the adhesion with the inorganic layer, is improved, and a further excellent barrier property can be realized. For details of the cardo polymer, reference can be made to paragraphs 0085 to 0095 of the above-mentioned JP-A-2005-096108. The thickness of the organic layer is preferably in the range of 0.05 μm to 10 μm, and more preferably in the range of 0.5 to 10 μm. When the organic layer is formed by a wet coating method, the film thickness of the organic layer is preferably in the range of 0.5 to 10 μm, and more preferably in the range of 1 μm to 5 μm. Moreover, when formed by the dry coating method, it is preferable that it exists in the range of 0.05 micrometer-5 micrometers, especially in the range of 0.05 micrometer-1 micrometer. This is because when the film thickness of the organic layer formed by the wet coating method or the dry coating method is within the above-described range, the adhesion with the inorganic layer can be further improved.

  Regarding the other details of the inorganic layer and the organic layer, reference can be made to the descriptions in JP-A-2007-290369, JP-A-2005-096108 and US2012 / 0113672A1.

  In the wavelength conversion member 1D, the wavelength conversion layer, the inorganic layer, the organic layer, and the support may be laminated in this order, between the inorganic layer and the organic layer, between the two organic layers, or between the two layers. A support may be disposed between the inorganic layers and laminated.

(Roughness imparting layer)
It is preferable that the barrier film 10 is provided with the uneven | corrugated provision layer 13 which provides an uneven | corrugated structure in the surface on the opposite side to the surface by the side of the wavelength conversion layer 30 side. It is preferable that the barrier film 10 has the unevenness imparting layer 13 because the blocking property and slipping property of the barrier film can be improved. The unevenness providing layer is preferably a layer containing particles. Examples of the particles include inorganic particles such as silica, alumina, and metal oxide, or organic particles such as crosslinked polymer particles. Moreover, although it is preferable to provide in the surface on the opposite side to the wavelength conversion layer of an uneven | corrugated provision layer and a barrier film, you may provide in both surfaces.

  The wavelength conversion member 1D can have a light scattering function in order to efficiently extract the fluorescence of the quantum dots to the outside. The light scattering function may be provided inside the wavelength conversion layer 30, or a layer having a light scattering function may be separately provided as the light scattering layer. The light scattering layer may be provided on the surface of the barrier layer 22 on the wavelength conversion layer 30 side, or may be provided on the surface of the support opposite to the wavelength conversion layer. In the case of providing the unevenness providing layer, the unevenness providing layer is preferably a layer that can also be used as a light scattering layer.

<Method for producing wavelength conversion member>
Next, an example of a method for manufacturing the wavelength conversion member 1D having an aspect in which the barrier films 10 and 20 including the barrier layers 12 and 22 on the supports 11 and 21 are provided on both surfaces of the wavelength conversion layer 30 will be described.
In the present embodiment, the wavelength conversion layer 30 can be formed by applying the prepared composition for wavelength conversion layer on the surface of the barrier films 10 and 20 and then curing it by light irradiation or heating. Known coating methods include curtain coating, dip coating, spin coating, print coating, spray coating, slot coating, roll coating, slide coating, blade coating, gravure coating, and wire bar method. The coating method is mentioned.

  Curing conditions can be appropriately set according to the type of anionic polymerizable compound to be used and the composition of the composition for wavelength conversion layer. Moreover, when the composition for wavelength conversion layers is a composition containing a solvent, you may perform a drying process for solvent removal before hardening.

  Curing of the composition for wavelength conversion layer may be performed in a state where the composition for wavelength conversion layer is sandwiched between two supports. One aspect of the manufacturing process of the wavelength conversion member including the curing process will be described below with reference to FIGS. However, the present invention is not limited to the following embodiments.

2 is a schematic configuration diagram of an example of a manufacturing apparatus for the wavelength conversion member 1D, and FIG. 3 is a partially enlarged view of the manufacturing apparatus shown in FIG.
The manufacturing apparatus according to this embodiment includes a feeder (not shown), an application unit 120 that forms the coating film 30M by applying the wavelength conversion layer composition on the barrier film 10, and the barrier film 20 is pasted on the coating film 30M. In addition, a laminate unit 130 that sandwiches the coating film 30M between the barrier film 10 and the barrier film 20, a curing unit 160 that cures the coating film 30M, and a winder (not shown) are provided.

  The manufacturing process of the wavelength conversion member using the manufacturing apparatus shown in FIGS. 2 and 3 is for the wavelength conversion layer on the surface of the first barrier film 10 (hereinafter also referred to as “first film 10”) that is continuously conveyed. A step of applying the composition to form a coating film, and laminating (overlapping) a second barrier film 20 (hereinafter also referred to as “second film 20”) continuously conveyed on the coating film. The first film 10 and the second film 20 are sandwiched between the first film 10 and the second film 20 and the first film 10 and the second film 20 are sandwiched between the first film 10 and the second film 20. The film 20 is wound around a backup roller, irradiated with light while being continuously conveyed, and polymerized and cured to form a wavelength conversion layer (cured layer). In this embodiment, a barrier film having a barrier property against oxygen and moisture is used for both the first film 10 and the second film 20. By setting it as this aspect, wavelength conversion member 1D by which both surfaces of the wavelength conversion layer were protected by the barrier film can be obtained. A wavelength conversion member having one surface protected by a barrier film may be used, and in that case, the barrier film side is preferably used as the side close to the outside air.

  More specifically, first, the first film 10 is continuously conveyed to the coating unit 120 from a delivery machine (not shown). For example, the first film 10 is sent from the sending machine at a conveying speed of 1 to 50 m / min. However, it is not limited to this conveyance speed. When delivered, for example, a tension of 20 to 150 N / m, preferably 30 to 100 N / m, is applied to the first film 10.

  In the application part 120, the composition for wavelength conversion layers (henceforth "application liquid" is also described) is apply | coated to the surface of the 1st film 10 conveyed continuously, and the coating film 30M (refer FIG. 3) is formed. The In the application unit 120, for example, a die coater 124 and a backup roller 126 disposed to face the die coater 124 are installed. The surface opposite to the surface on which the coating film 30M of the first film 10 is formed is wound around the backup roller 126, and the coating liquid is applied from the discharge port of the die coater 124 onto the surface of the first film 10 that is continuously conveyed. Thus, the coating film 30M is formed. Here, the coating film 30 </ b> M refers to a composition for a wavelength conversion layer before being applied on the first film 10.

  In the present embodiment, the die coater 124 to which the extrusion coating method is applied is shown as the coating device in the coating unit 120, but the present invention is not limited to this. For example, a coating apparatus to which various methods such as a curtain coating method, a rod coating method, or a roll coating method are applied can be used.

  The first film 10 that has passed through the coating unit 120 and has the coating film 30M formed thereon is continuously conveyed to the laminating unit 130. In the laminating unit 130, the second film 20 continuously conveyed is laminated on the coating film 30 </ b> M, and the coating film 30 </ b> M is sandwiched between the first film 10 and the second film 20.

  The laminating unit 130 is provided with a laminating roller 132 and a heating chamber 134 that surrounds the laminating roller 132. The heating chamber 134 is provided with an opening 136 for allowing the first film 10 to pass therethrough and an opening 138 for allowing the second film 20 to pass therethrough.

  A backup roller 162 is disposed at a position facing the laminating roller 132. The first film 10 on which the coating film 30M is formed is wound around the backup roller 162 on the surface opposite to the surface on which the coating film 30M is formed, and is continuously conveyed to the laminating position P. Lamination position P means the position where the contact between the second film 20 and the coating film 30M starts. The first film 10 is preferably wound around the backup roller 162 before reaching the laminating position P. This is because even if wrinkles occur in the first film 10, the wrinkles are corrected and removed by the backup roller 162 before reaching the laminate position P. Therefore, the position (contact position) where the first film 10 is wound around the backup roller 162 and the distance L1 to the laminate position P are preferably long, for example, 30 mm or more is preferable, and the upper limit is usually It is determined by the diameter of the backup roller 162 and the pass line.

  In the present embodiment, the second film 20 is laminated by the backup roller 162 and the laminating roller 132 used in the curing unit 160. That is, the backup roller 162 used in the curing unit 160 is also used as a roller used in the laminating unit 130. However, the present invention is not limited to the above form, and a laminating roller may be installed in the laminating unit 130 in addition to the backup roller 162 so that the backup roller 162 is not used.

  By using the backup roller 162 used in the curing unit 160 in the laminating unit 130, the number of rollers can be reduced. The backup roller 162 can also be used as a heat roller for the first film 10.

  The second film 20 delivered from a delivery machine (not shown) is wound around the laminating roller 132 and continuously conveyed between the laminating roller 132 and the backup roller 162. The second film 20 is laminated on the coating film 30M formed on the first film 10 at the laminating position P. Thereby, the coating film 30 </ b> M is sandwiched between the first film 10 and the second film 20. Lamination refers to laminating the second film 20 on the coating film 30M.

  The distance L2 between the laminating roller 132 and the backup roller 162 is a value of the total thickness of the first film 10, the wavelength conversion layer (cured layer) 30 obtained by polymerizing and curing the coating film 30M, and the second film 20. The above is preferable. Moreover, it is preferable that L2 is below the length which added 5 mm to the total thickness of the 1st film 10, the coating film 30M, and the 2nd film 20. FIG. By making the distance L2 equal to or less than the total thickness plus 5 mm, it is possible to prevent bubbles from entering between the second film 20 and the coating film 30M. Here, the distance L2 between the laminating roller 132 and the backup roller 162 is the shortest distance between the outer circumferential surface of the laminating roller 132 and the outer circumferential surface of the backup roller 162.

  The rotational accuracy of the laminating roller 132 and the backup roller 162 is 0.05 mm or less, preferably 0.01 mm or less in radial runout. The smaller the radial runout, the smaller the thickness distribution of the coating film 30M.

  Further, in order to suppress thermal deformation after the coating film 30M is sandwiched between the first film 10 and the second film 20, the difference between the temperature of the backup roller 162 of the curing unit 160 and the temperature of the first film 10 The difference between the temperature of the backup roller 162 and the temperature of the second film 20 is preferably 30 ° C. or less, more preferably 15 ° C. or less, and most preferably the same.

  In order to reduce the difference from the temperature of the backup roller 162, when the heating chamber 134 is provided, it is preferable to heat the first film 10 and the second film 20 in the heating chamber 134. For example, hot air is supplied to the heating chamber 134 by a hot air generator (not shown), and the first film 10 and the second film 20 can be heated.

  The first film 10 may be heated by the backup roller 162 by being wound around the temperature-controlled backup roller 162.

  On the other hand, the second film 20 can be heated by the laminating roller 132 by using the laminating roller 132 as a heat roller. However, the heating chamber 134 and the heat roller are not essential, and can be provided as necessary.

  Next, in a state where the coating film 30M is sandwiched between the first film 10 and the second film 20, it is continuously conveyed to the curing unit 160. In the embodiment shown in the drawing, curing in the curing unit 160 is performed by light irradiation, but when the polymerizable compound contained in the composition for wavelength conversion layer is polymerized by heating, heating such as blowing of warm air is performed. Thus, curing can be performed.

A light irradiation device 164 is provided at a position facing the backup roller 162 and the backup roller 162. Between the backup roller 162 and the light irradiation device 164, the first film 10 and the second film 20 sandwiching the coating film 30M are continuously conveyed. What is necessary is just to determine the light irradiated by a light irradiation apparatus according to the kind of photopolymerizable compound contained in the composition for wavelength conversion layers, and an ultraviolet-ray is mentioned as an example. Here, the ultraviolet light refers to light having a wavelength of 280 to 400 nm. As a light source that generates ultraviolet rays, for example, a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, a carbon arc lamp, a metal halide lamp, a xenon lamp, or the like can be used. What is necessary is just to set the light irradiation amount to the range which can advance the polymerization hardening of a coating film, for example, can irradiate the coating film 30M with the ultraviolet-ray of the irradiation amount of 100-10000mJ / cm < ² > as an example.

  In the curing unit 160, the first film 10 is wound around the backup roller 162 in a state where the coating film 30 </ b> M is sandwiched between the first film 10 and the second film 20, and is continuously conveyed from the light irradiation device 164. The wavelength conversion layer 30 can be formed by performing light irradiation to cure the coating film 30M.

  In the present embodiment, the first film 10 side is wound around the backup roller 162 and continuously conveyed, but the second film 20 may be wound around the backup roller 162 and continuously conveyed.

  Wrapping around the backup roller 162 means a state in which either the first film 10 or the second film 20 is in contact with the surface of the backup roller 162 at a certain wrap angle. Accordingly, the first film 10 and the second film 20 move in synchronization with the rotation of the backup roller 162 while being continuously conveyed. Winding around the backup roller 162 may be at least during the irradiation of ultraviolet rays.

  The backup roller 162 includes a cylindrical main body and rotating shafts disposed at both ends of the main body. The main body of the backup roller 162 has a diameter of φ200 to 1000 mm, for example. There is no restriction on the diameter φ of the backup roller 162. In consideration of curl deformation of the laminated film, equipment cost, and rotation accuracy, the diameter is preferably 300 to 500 mm. By attaching a temperature controller to the main body of the backup roller 162, the temperature of the backup roller 162 can be adjusted.

  The temperature of the backup roller 162 is determined in consideration of heat generation during light irradiation, curing efficiency of the coating film 30M, and occurrence of wrinkle deformation on the backup roller 162 of the first film 10 and the second film 20. can do. For example, the backup roller 162 is preferably set to a temperature range of 10 to 95 ° C, and more preferably 15 to 85 ° C. Here, the temperature related to the roller refers to the surface temperature of the roller.

  A distance L3 between the laminate position P and the light irradiation device 164 can be set to 30 mm or more, for example.

  The coating 30 </ b> M is cured by the light irradiation to become the wavelength conversion layer 30, and the wavelength conversion member 1 </ b> D including the first film 10, the wavelength conversion layer 30, and the second film 20 is manufactured. The wavelength conversion member 1D is peeled off from the backup roller 162 by the peeling roller 180. The wavelength conversion member 1D is continuously conveyed to a winder (not shown), and then the wavelength conversion member 1D is wound into a roll by the winder.

[Backlight unit]
Next, the backlight unit provided with the wavelength conversion member of the present invention will be described. FIG. 4 is a schematic cross-sectional view showing the backlight unit.
As shown in FIG. 4, the backlight unit 2 of the present invention includes a light source 1A that emits primary light (blue light L _B ), and a light guide plate 1B that guides and emits primary light emitted from the light source 1A. A planar light source 1C, a wavelength conversion member 1D provided on the planar light source 1C, a retroreflective member 2B disposed to face the planar light source 1C across the wavelength conversion member 1D, and a planar light source across 1C and a reflecting plate 2A disposed opposite and the wavelength converting member 1D, the wavelength conversion member 1D, at least a portion of the primary light L _B emitted from the surface light source 1C as excitation light, fluorescent , And the secondary light (green light L _G , red light L _R ) composed of this fluorescence and the primary light L _B transmitted through the wavelength conversion member 1D are emitted. L _G, the _{L R,} and _{L B,} emits white light Lw from the surface of the retroreflective member 2B.
The shape of the wavelength conversion member 1D is not particularly limited, and may be an arbitrary shape such as a sheet shape or a bar shape.

In FIG. 4, L _B emitted from the wavelength conversion member _1D, L _G, and L _R is incident on the retroreflective member 2B, the light incident, between the reflective plate 2A and the retroreflective member 2B The reflection is repeated and passes through the wavelength conversion member 1D many times. As a result, the wavelength conversion member 1D in a sufficient amount of excitation light (the blue light L _B) is, quantum dots 30A that emits red light L _R, is absorbed by the quantum dots 30B for emitting green light L _G, the amount of required Fluorescence (green light L _G , red light L _R ) is emitted, and white light L _W is embodied and emitted from the retroreflective member 2B.

  When ultraviolet light is used as excitation light, light is emitted from the quantum dots 30A by making ultraviolet light incident on the wavelength conversion layer 30 including the quantum dots 30A and 30B in FIG. 1 and 30C (not shown) as excitation light. White light can be embodied by red light, green light emitted by the quantum dots 30B, and blue light emitted by the quantum dots 30C.

From the viewpoint of realizing high luminance and high color reproducibility, it is preferable to use a backlight unit that has been converted to a multi-wavelength light source. For example, blue light having an emission center wavelength in a wavelength band of 430 to 480 nm and a peak of emission intensity with a half width of 100 nm or less, and an emission center wavelength in a wavelength band of 520 to 560 nm, and a half width of It is preferable to emit green light having an emission intensity peak that is 100 nm or less and red light having an emission center wavelength in the wavelength band of 600 to 680 nm and having an emission intensity peak that is 100 nm or less. .
From the viewpoint of further improving luminance and color reproducibility, the wavelength band of blue light emitted from the backlight unit is more preferably 440 to 460 nm.
From the same viewpoint, the wavelength band of the green light emitted from the backlight unit is more preferably 520 to 545 nm.
From the same viewpoint, the wavelength band of red light emitted from the backlight unit is more preferably 610 to 640 nm.

  From the same viewpoint, the half-value widths of the emission intensity of blue light, green light, and red light emitted from the backlight unit are all preferably 80 nm or less, more preferably 50 nm or less, and 40 nm or less. More preferably, it is more preferably 30 nm or less. Among these, it is particularly preferable that the half-value width of each emission intensity of blue light is 25 nm or less.

  Examples of the light source 1A include those that emit blue light having an emission center wavelength in the wavelength band of 430 nm to 480 nm, and those that emit ultraviolet light. As the light source 1A, a light emitting diode, a laser light source, or the like can be used.

As shown in FIG. 4, the planar light source 1 </ b> C may be a light source including a light source 1 </ b> A and a light guide plate 1 </ b> B that guides and emits primary light emitted from the light source 1 </ b> A. The light source may be a light source that is arranged in a plane parallel to the member 1D and includes a diffusion plate instead of the light guide plate 1B. The former light source is generally called an edge light method, and the latter light source is generally called a direct type.
As the configuration of the backlight unit, the edge light method using a light guide plate, a reflection plate, or the like as a constituent member has been described in FIG. 4, but a direct type may be used. Any known light guide plate can be used without any limitation.
In the present embodiment, a case where a planar light source is used as the light source has been described as an example. However, a light source other than the planar light source can be used as the light source.

  When a light source that emits blue light is used, the wavelength conversion layer preferably includes at least quantum dots 30A that are excited by excitation light and emit red light, and quantum dots 30B that emit green light. Thereby, white light can be embodied by blue light emitted from the light source and transmitted through the wavelength conversion member, and red light and green light emitted from the wavelength conversion member.

Alternatively, in another aspect, a light source that emits ultraviolet light having an emission center wavelength in a wavelength band of 300 nm to 430 nm (ultraviolet light source), for example, an ultraviolet light emitting diode can be used.
In another embodiment, a laser light source can be used instead of the light emitting diode.

  Further, the reflecting plate 2A is not particularly limited, and known ones can be used, and are described in Japanese Patent No. 3416302, Japanese Patent No. 3363565, Japanese Patent No. 4091978, Japanese Patent No. 3448626, etc. Incorporated into the present invention.

  The retroreflective member 2B is composed of a known diffusion plate, diffusion sheet, prism sheet (eg, BEF series manufactured by Sumitomo 3M), reflective polarizing film (eg, DBEF series manufactured by Sumitomo 3M), and the like. Also good. The configuration of the retroreflective member 2B is described in Japanese Patent No. 3416302, Japanese Patent No. 3363565, Japanese Patent No. 4091978, Japanese Patent No. 3448626, and the contents of these publications are incorporated in the present invention.

[Liquid Crystal Display]
The backlight unit 2 described above can be applied to a liquid crystal display device. FIG. 5 shows a schematic cross-sectional view of the liquid crystal display device of the present invention.
As shown in FIG. 5, the liquid crystal display device 4 includes the backlight unit 2 according to the above-described embodiment and the liquid crystal cell unit 3 disposed to face the retroreflective member 2 </ b> B in the backlight unit 2. The liquid crystal cell unit 3 has a configuration in which the liquid crystal cell 31 is sandwiched between polarizing plates 32 and 33. The polarizing plates 32 and 33 have polarizing plate protective films 321 and 323 on both main surfaces of the polarizers 322 and 332, respectively. It is configured to be protected by 331 and 333.

  There are no particular limitations on the liquid crystal cell 31, the polarizing plates 32 and 33, and the components thereof that constitute the liquid crystal display device 4, and those produced by known methods and commercially available products can be used without any limitation. It is of course possible to provide a known intermediate layer such as an adhesive layer between the layers.

  The driving mode of the liquid crystal cell 31 is not particularly limited, and is twisted nematic (TN), super twisted nematic (STN), vertical alignment (VA), in-plane switching (IPS), optically compensated bend cell (OCB). ) And other modes can be used. The liquid crystal cell is preferably VA mode, OCB mode, IPS mode, or TN mode, but is not limited thereto. As an example of the configuration of the VA mode liquid crystal display device, the configuration shown in FIG. 2 of Japanese Patent Application Laid-Open No. 2008-262161 is given as an example. However, the specific configuration of the liquid crystal display device is not particularly limited, and a known configuration can be adopted.

  The liquid crystal display device 4 further includes an accompanying functional layer such as an optical compensation member that performs optical compensation and an adhesive layer as necessary. In addition to or in place of color filter substrate, thin layer transistor substrate, lens film, diffusion sheet, hard coat layer, antireflection layer, low reflection layer, antiglare layer, etc., forward scattering layer, primer layer, antistatic layer, undercoat A surface layer such as a layer may be disposed.

  The polarizing plate 32 on the backlight side may have a retardation film as the polarizing plate protective film 323 on the liquid crystal cell 31 side. As such a retardation film, a known cellulose acylate film or the like can be used.

  Since the backlight unit 2 and the liquid crystal display device 4 are provided with a wavelength conversion layer having a high polymerization reaction rate and good curability according to the present invention, the backlight unit 2 and the liquid crystal display device become a high-brightness backlight unit and liquid crystal display device.

  Hereinafter, the present invention will be described more specifically based on examples. The materials, amounts used, ratios, processing details, processing procedures, and the like shown in the following examples can be changed as appropriate without departing from the spirit of the present invention. Therefore, the scope of the present invention should not be construed as being limited by the specific examples shown below.

(Preparation of barrier film 10)
Using a polyethylene terephthalate (PET) film (trade name “Cosmo Shine (registered trademark) A4300”, thickness 50 μm, manufactured by Toyobo Co., Ltd.) as a support, an organic layer and an inorganic layer were formed on one side of the support by the following procedure. Sequentially formed.

-Formation of organic layer-
Prepare trimethylolpropane triacrylate (product name “TMPTA”, manufactured by Daicel Ornex Co., Ltd.) and photopolymerization initiator (trade name “ESACURE (registered trademark) KTO46”, manufactured by Lamberti Co., Ltd.) Weighed to 95: 5 and dissolved them in methyl ethyl ketone to obtain a coating solution having a solid content concentration of 15%. This coating solution was applied onto a PET film with a roll-to-roll using a die coater, and passed through a drying zone at 50 ° C. for 3 minutes. Thereafter, the sample was irradiated with ultraviolet rays (integrated irradiation amount: about 600 mJ / cm ² ) in a nitrogen atmosphere, cured by ultraviolet curing, and wound up. The thickness of the organic layer formed on the support was 1 μm.

-Formation of inorganic layer-
Next, an inorganic layer (silicon nitride layer) was formed on the surface of the organic layer using a roll-to-roll CVD apparatus. Silane gas (flow rate 160 sccm), ammonia gas (flow rate 370 sccm), hydrogen gas (flow rate 590 sccm), and nitrogen gas (flow rate 240 sccm) were used as source gases. A high frequency power supply having a frequency of 13.56 MHz was used as the power supply. The film forming pressure was 40 Pa, and the reached film thickness was 50 nm. Thus, the barrier film 10 in which the inorganic layer was laminated on the surface of the organic layer formed on the support was produced.

(Production of surface-treated barrier film)
A silane coupling agent-containing composition having the following composition was prepared and used as a surface treatment composition (surface treatment coating solution). This composition for surface treatment was applied by roll-to-roll using a die coater on the inorganic layer of the barrier film 10 at a coating amount of ² ml / m ² and passed through a drying zone at 120 ° C. for 3 minutes. . In this way, a surface-treated barrier film whose surface was treated with a silane coupling agent was prepared.

(Composition for surface treatment)
The composition for surface treatment was prepared with the following materials and blending ratios.
Isopropanol / ethanol / acetic acid / water / Shin-Etsu Chemical Co., Ltd. KBM-5103 (Silane coupling agent-containing solution) = 14/14/2/20/50 (mass ratio)

(Preparation of wavelength conversion layer composition used in Example 1 and preparation of coating solution)
The following composition 1 for wavelength conversion layer was prepared, filtered through a polypropylene filter having a pore size of 0.2 μm, dried under reduced pressure for 30 minutes, and used as a coating solution.

-Composition for wavelength conversion layer 1-
Toluene dispersion of quantum dots 1 (emission maximum: 520 nm) 10 parts by mass Toluene dispersion of quantum dots 2 (emission maximum: 630 nm) 1 part by weight Celoxide 2021P (manufactured by Daicel Corporation) 100 parts by weight Photobase generator WPBG-266 (Made by Wako Pure Chemical Industries Ltd.) 3 mass parts In addition, the quantum dot density | concentration of the toluene dispersion of the quantum dot 1 and the quantum dot 2 is 1 mass%.

The quantum dot 1 is a core / shell type quantum dot in which the core is made of CdSe and the shell is made of ZnS, the emission center wavelength is 520 nm, and the half-value width is 25 nm. Octylphosphine oxide is coordinated to quantum dot 1.
The quantum dot 2 is a core / shell type quantum dot having a core made of CdSe and a shell made of ZnS, and has an emission center wavelength of 630 nm and a half-value width of 30 nm.
As a ligand, trioctylphosphine and trioctylphosphine oxide are coordinated to the quantum dot 2.
The quantum dot coordinated with such a ligand was synthesized with reference to the method described in The Journal Physical Chemistry, 101, pp 9463-9475, 1997.

(Preparation of composition for wavelength conversion layer used in other examples and comparative examples and preparation of coating solution)
A composition for wavelength conversion layer was prepared with the materials and mass ratios shown in Table 1, filtered through a polypropylene filter having a pore size of 0.2 μm, and then dried under reduced pressure for 30 minutes to be used as a coating solution.

(Preparation of wavelength conversion member of Example 1)
The barrier film 10 produced by the above-described procedure was used as the first film 10 and the second film 20, and a wavelength conversion member was obtained by the manufacturing process described with reference to FIGS. Specifically, the barrier film 10 is prepared as the first film 10, and the coating solution prepared above is applied on the surface of the inorganic layer with a die coater while continuously transporting at a tension of 1 m / min and 60 N / m. A coating film having a thickness of 50 μm was formed. Next, the first film 10 on which the coating film is formed is wound around a backup roller, and the second film 20 is laminated on the coating film in such a direction that the inorganic layer surface is in contact with the coating film. While being continuously conveyed with the coating film being sandwiched at 20, a heating zone at 100 ° C. was passed for 3 minutes. Thereafter, using a 160 W / cm air-cooled metal halide lamp (manufactured by Eye Graphics Co., Ltd.), it was cured by irradiating with ultraviolet rays to form a wavelength conversion layer containing quantum dots. The irradiation amount of ultraviolet rays was 2000 mJ / cm ² . In FIG. 3, L1 was 50 mm, L2 was 1 mm, and L3 was 50 mm.

(Production of wavelength conversion member of Examples 2 and 11)
A wavelength conversion member was prepared in the same manner as in Example 1 except that the surface-treated barrier film was used instead of the barrier film 10 and the coating liquid used in the other examples and comparative examples was used.

(Production of wavelength conversion member of Example 9)
The wavelength conversion member of Example 9 was produced by heating and curing at 120 ° C. for 60 minutes instead of ultraviolet irradiation in the production procedure of Example 1.

(Production of wavelength conversion members of Examples 3 to 8, 10 and Comparative Examples 1 to 4)
A wavelength conversion member was produced in the same manner as in Example 1 except that the coating liquid used in the other examples and comparative examples was used.

(Evaluation of photocurability of wavelength conversion layer)
Photocurability is calculated using the commercially available FT-IR apparatus (PerkinElmer, Frontier series), calculating the reaction rate from the absorption peak intensity at 789 cm ^{−1 based on} the monomer solution (polymerizable compound). Based on the evaluation. The measurement results are shown in Table 1.

<Evaluation criteria>
A: Reaction rate of 90% or more B: Reaction rate of 80 or more and less than 90% C: Reaction rate of 50 or more and less than 80% D: Reaction rate of less than 50%

(Measurement of brightness)
A commercially available tablet terminal (trade name “Kindle (registered trademark) Fire HDX 7”, manufactured by Amazon) having a blue light source in the backlight unit was disassembled, and the backlight unit was taken out. The wavelength conversion members produced in Examples 1 to 11 and Comparative Examples 1 to 4 cut out in a rectangular shape are placed on the light guide plate of the taken-out backlight unit, and two prisms in which the direction of the surface uneven pattern is orthogonal The sheets were stacked. Luminance meter (trade name “SR3”, manufactured by TOPCON, Inc.) in which the luminance Y of the light emitted from the blue light source and transmitted through the wavelength conversion member and the two prism sheets is set at a position of 740 mm perpendicular to the surface of the light guide plate ). The luminance Y was evaluated based on the following evaluation criteria. The measurement results are shown in Table 1.

<Evaluation criteria>
A: Y ≧ 10,000 [cd / m ² ]
B: 9,000 ≦ Y <10,000 [cd / m ² ]
C: 8,000 ≦ Y <9,000 [cd / m ² ]
D: Y <8,000 [cd / m ² ]

Details of the notation in Table 1 are described below.
Celoxide 2021P: cycloaliphatic epoxy monomer, manufactured by Daicel Corporation Cyclomer M100: alicyclic epoxy monomer, manufactured by Daicel Corporation OXT-221: 3-ethyl-3 {[(3-ethyloxetane-3-yl) methoxy] Methyl} oxetane, manufactured by Toa Gosei Co., Ltd. TMPO: 3-ethyl-3-oxetanemethanol, manufactured by Tokyo Chemical Industry Co., Ltd. WPBG-266: photobase generator, manufactured by Wako Pure Chemical Industries, Ltd. WPBG-300: light Base generator, Wako Pure Chemical Industries, Ltd. WPBG-168: Photobase generator, Wako Pure Chemical Industries, Ltd. U-CAT SA102: Thermal base generator, San Apro Corporation 828US: Bisphenol A, Mitsubishi Chemical AMP-10G: 2-phenoxyethyl acrylate, Shin-Nakamura Chemical Co., Ltd.
SP-170: Photoacid generator, manufactured by Adeka Corporation Irgacure 819: Photoradical generator, manufactured by BASF

As shown in Table 1, Examples 1 to 11 using the wavelength conversion layer composition of the present invention are more curable than Comparative Examples 1 to 4 using only a photoacid generator and a radical generator. Excellent. Moreover, the liquid crystal display device incorporating the wavelength conversion member of the present invention is excellent in luminance. That is, since the wavelength conversion layer is sufficiently cured, there is no side reaction between the quantum dots and oxygen, so the luminance is considered high. In particular, Example 1 using an anionic polymerization initiator that generates guanidine which is a strong base was more excellent in curability than Example 7 using an anionic polymerization initiator that generates a primary amine. .
Further, from Examples 7 and 8, the smaller the amount of the anionic polymerization initiator added, the higher the luminance of the liquid crystal display device. This means that by reducing the addition amount of the anionic polymerization initiator, the epoxy resin, which is a cured product of the polymerizable compound, is prevented from being colored by the anionic polymerization initiator, and the absorption of excitation light is inhibited by the coloring. I think it was because I was able to prevent it.

DESCRIPTION OF SYMBOLS 1A Light source 1B Light guide plate 1C Planar light source 1D Wavelength conversion member 2 Backlight unit 2A Reflection plate 2B Retroreflective member 3 Liquid crystal cell unit 4 Liquid crystal display device 10, 20 Barrier film 11, 21 Support body 12, 22 Barrier layer 12a, 22a organic layer 12b, 22b inorganic layer 13 uneven imparting layer 30 wavelength conversion layer 30A, 30B quantum dots 30P organic matrix 31 liquid crystal cell _{L B} excitation light (primary light, blue light)
_LR red light (secondary light, fluorescence)
L _G the green light (secondary light, fluorescence)
L _W white light

Claims (9)

Quantum dots that are excited by excitation light to emit fluorescence;
A ligand having a Lewis basic coordinating group coordinated to the surface of the quantum dot;
An anionic polymerizable compound;
An anionic polymerization initiator;
The composition for wavelength conversion layers containing this.   The composition for wavelength conversion layers according to claim 1, wherein the ligand is a phosphine compound, an amine compound, and a thiol compound.   The composition for wavelength conversion layers according to claim 1 or 2, wherein the base generated from the anionic polymerization initiator is an amine, imidazole, amidine, or guanidine.   The wavelength conversion layer composition according to any one of claims 1 to 3, wherein the anionic polymerizable compound is a compound having at least one functional group selected from an epoxy group and an oxetanyl group.   The anionic polymerization initiator is cyclohexylammonium 2- (3-benzoylphenyl) propionate, 1,2-dicyclohexyl-4,4,5,5-tetramethylbiguanidinium n-butyltriphenylborate, 1,2-diisopropyl A salt of -3- [bis (dimethylamino) methylene] guanidium 2- (3-benzoylphenyl) propionate or 1,8-diazabicyclo [5.4.0] undecene-7 and octylic acid 5. The wavelength conversion layer composition according to any one of 4 above.   The wavelength conversion according to any one of claims 1 to 5, wherein an addition amount of the anionic polymerization initiator is 0.1 parts by mass or more and 10.0 parts by mass or less with respect to 100 parts by mass of the anion polymerizable compound. Layer composition.   The wavelength conversion member provided with the wavelength conversion layer formed by hardening | curing the composition for wavelength conversion layers of any one of Claims 1-6. A light source that emits primary light;
The wavelength conversion member according to claim 7 provided on the light source;
A retroreflective member disposed opposite to the light source with the wavelength conversion member interposed therebetween;
A reflector unit disposed opposite to the wavelength conversion member across the light source, and a backlight unit comprising:
The wavelength conversion member is a backlight unit that emits fluorescence using at least a part of the primary light emitted from the light source as excitation light and emits at least light including secondary light composed of the fluorescence. The backlight unit according to claim 8,
A liquid crystal display device comprising at least a liquid crystal cell disposed opposite to the retroreflective member side of the backlight unit.