JP2020021033A - Ink composition, cured product thereof, light conversion layer, and color filter - Google Patents

Abstract

To provide an ink composition that can be used to form pixel units with superior capability to maintain external quantum efficiency.SOLUTION: An ink composition is provided, comprising luminescent nanocrystal particles, and a photopolymerizable compound containing an allyl ether group and an ethylenically unsaturated group capable of reacting with the allyl ether group to form an intramolecular ring.SELECTED DRAWING: None

Description

  The present invention relates to an ink composition and a cured product thereof, a light conversion layer, and a color filter.

  Conventionally, a pixel portion (color filter pixel portion) in a display such as a liquid crystal display device is, for example, a curable resist containing red organic pigment particles or green organic pigment particles, and an alkali-soluble resin and / or an acrylic monomer. It has been manufactured by photolithography using materials.

  In recent years, low power consumption of the display has been strongly demanded, and instead of the red organic pigment particles or the green organic pigment particles, for example, quantum dots, quantum rods, luminescent nanocrystal particles such as other inorganic phosphor particles, etc. A method of forming a pixel portion such as a red pixel and a green pixel by using is being actively researched.

  By the way, the method of manufacturing a color filter by the photolithography method has a drawback that a resist material other than a pixel portion including relatively expensive luminescent nanocrystal particles is wasted due to a feature of the manufacturing method. Under such circumstances, in order to eliminate the waste of the resist material as described above, studies have been started to form a pixel portion of the light conversion substrate by an inkjet method (Patent Document 1).

International Publication No. 2008/001693

  In a pixel portion (for example, a color filter pixel portion) formed by an ink composition containing luminescent nanocrystal particles, an initial external quantum efficiency (EQE: External Quantum Efficiency) is maintained for a long time from the viewpoint of low power consumption and the like. It needs to be maintained.

  Thus, the present invention provides an ink composition capable of forming a pixel portion having excellent external quantum efficiency maintenance performance, a cured product of the ink composition, and a light conversion layer and a color filter using the ink composition. The purpose is to:

  One aspect of the present invention comprises a luminescent nanocrystal particle, an allyl ether group, and a photopolymerizable compound containing an ethylenically unsaturated group capable of forming an intramolecular ring by reacting with the allyl ether group. To an ink composition.

  According to the above-described ink composition of the present invention, it is possible to form a pixel portion having excellent external quantum efficiency maintaining performance.

［式（ＩＩ）中、＊は結合手を示す。］ The photopolymerizable compound may include a structure represented by the following formula (II) as the structure having the ethylenically unsaturated group.

[In formula (II), * represents a bond. ]

  The ink composition may further contain a monofunctional or polyfunctional (meth) acrylate.

  The content of the luminescent nanocrystal particles may be more than 20% by mass based on the mass of the nonvolatile components of the ink composition.

  The ink composition may further contain a thiol compound.

  The ink composition may further contain an antioxidant.

  The ink composition may further contain light scattering particles.

  The content of the inorganic component in the ink composition may be 30% by mass or more based on the mass of the nonvolatile components of the ink composition.

  The above ink composition can be used for forming a light conversion layer. That is, the ink composition of the present invention may be an ink composition for forming a light conversion layer.

  The ink composition may be an ink composition (inkjet ink) used in an inkjet system. As described above, since the ink composition of the present invention tends to have excellent ejection stability, it can be suitably used as an inkjet ink.

  One aspect of the present invention relates to a cured product of an ink composition containing luminescent nanocrystal particles and a polymer containing a structural unit having an ether ring.

  According to the cured product of the ink composition of the present invention, it is possible to obtain a pixel portion having excellent external quantum efficiency maintenance performance.

  One aspect of the present invention includes a plurality of pixel portions and a light-shielding portion provided between the plurality of pixel portions, and the plurality of pixel portions includes a light-emitting pixel portion including a cured product of the above-described ink composition. And a light conversion layer.

  The light conversion layer contains, as the luminescent pixel portion, luminescent nanocrystalline particles that absorb light having a wavelength in the range of 420 to 480 nm and emit light having an emission peak wavelength in the range of 605 to 665 nm. And a second luminescent pixel portion containing luminescent nanocrystalline particles that absorb light having a wavelength in the range of 420 to 480 nm and emit light having an emission peak wavelength in the range of 500 to 560 nm. , May be provided.

  The light conversion layer may further include a non-light emitting pixel portion containing light scattering particles.

  One aspect of the present invention relates to a color filter including the above-described light conversion layer.

  ADVANTAGE OF THE INVENTION According to this invention, the ink composition which can form the pixel part excellent in the maintenance performance of external quantum efficiency, the hardened | cured material of the said ink composition, and the light conversion layer and the color filter using the said ink composition are provided. be able to.

FIG. 1 is a schematic sectional view of a color filter according to one embodiment of the present invention.

  Hereinafter, embodiments of the present invention will be described in detail.

<Ink composition>
In one embodiment, the ink composition includes a light-emitting nanocrystalline particle, an allyl ether group, and a photopolymerizable compound containing an ethylenically unsaturated group capable of forming an intramolecular ring by reacting with the allyl ether group, And a luminescent ink composition. Since the ink composition of one embodiment has such a configuration, the external quantum efficiency can be maintained for a long time. That is, the ink composition of one embodiment is excellent in the performance of maintaining the external quantum efficiency. The reason why such an effect is obtained is not clear, but the present inventors speculate as follows.

  Since the ink composition of the present embodiment contains the specific photopolymerizable compound, the curing reaction of the ink composition of the present embodiment forms an intramolecular ring (ether ring) by an intramolecular reaction of the photopolymerizable compound. It progresses by polymerizing while performing. Therefore, the pixel portion formed by the ink composition of the present embodiment (the pixel portion including the cured product of the ink composition of the present embodiment) contains a polymer containing a structural unit having an ether ring as a curing component. It will be. In the present embodiment, it is presumed that the maintenance rate of the external quantum efficiency of the pixel portion is improved due to the fact that the intramolecular movement of the curing component is controlled by the ether ring.

  Further, when a polymer containing a structural unit having an ether ring is introduced into a pixel portion by a conventional ink composition, it is necessary to include a polymer containing a structural unit having an ether ring in the ink composition. The coalescence increases the viscosity of the ink composition. On the other hand, in the ink composition of the present embodiment, since the photopolymerizable compound becomes a polymer after forming the pixel portion, it is not necessary to include the polymer in the ink composition. Therefore, in the present embodiment, an ink composition having a lower viscosity can be obtained. Further, when the conventional ink composition is used for forming a pixel portion by an inkjet method, nozzle clogging or the like occurs due to an increase in the viscosity of the ink composition, and sufficient ejection stability is obtained. May not be possible. On the other hand, in the ink composition of the present embodiment, since the photopolymerizable compound becomes a polymer after forming the pixel portion, the polymer is introduced into the pixel portion while suppressing an increase in the viscosity of the ink composition. can do. Therefore, both the ejection stability and the performance of maintaining the external quantum efficiency can be achieved.

  The ink composition of one embodiment is used for forming a light conversion layer (for example, for a color filter) used for forming a pixel portion of a light conversion layer included in a color filter or the like by a method such as a photolithography method or an inkjet method. )).

  The ink composition of one embodiment can be applied as an ink used in a method for manufacturing a known and conventional color filter, but without wasteful consumption of materials such as relatively expensive luminescent nanocrystal particles and a solvent. Since the pixel portion (light conversion layer) can be formed only by using a necessary amount in a necessary portion, it is preferable to use a pixel portion (light conversion layer) which is appropriately prepared and used so as to be more suitable for an inkjet system than for a photolithography system.

  When forming a pixel portion containing luminescent nanocrystal particles by an inkjet method using a conventional ink composition, it is difficult to achieve both excellent ejection stability and excellent external quantum efficiency maintenance performance. However, according to the ink composition of one embodiment, it is possible to achieve both excellent ejection stability and excellent performance of maintaining external quantum efficiency even in an ink jet system. That is, the ink composition according to one embodiment is suitably used for forming a color filter pixel portion by an inkjet method.

  Hereinafter, an ink composition for a color filter (inkjet ink for a color filter) containing a luminescent nanocrystal particle, a photopolymerizable compound, a photopolymerization initiator, and light scattering particles and used for an ink jet method will be described as an example. explain.

[Luminescent nanocrystalline particles]
A luminescent nanocrystal particle is a nanosized crystal that absorbs excitation light and emits fluorescence or phosphorescence. For example, the maximum particle size measured by a transmission electron microscope or a scanning electron microscope is 100 nm or less. It is a crystal.

  The luminescent nanocrystal particles can emit light (fluorescence or phosphorescence) having a wavelength different from the absorbed wavelength, for example, by absorbing light having a predetermined wavelength. The luminescent nanocrystal particles may be red luminescent nanocrystal particles (red luminescent nanocrystal particles) that emit light having a luminescence peak wavelength in the range of 605 to 665 nm (red light). It may be green light-emitting nanocrystal particles (green light-emitting nanocrystal particles) that emit light (green light) having an emission peak wavelength in the range, and light (blue light) having an emission peak wavelength in the range of 420 to 480 nm. ) That emit blue light-emitting nanocrystal particles (blue light-emitting nanocrystal particles). In the present embodiment, the ink composition preferably includes at least one of these luminescent nanocrystal particles. The light absorbed by the luminescent nanocrystal particles is, for example, light (blue light) having a wavelength in the range of 400 nm or more and less than 500 nm (particularly, light having a wavelength in the range of 420 to 480 nm), or in the range of 200 nm to 400 nm. (Ultraviolet light). The emission peak wavelength of the luminescent nanocrystal particles can be confirmed in, for example, a fluorescence spectrum or a phosphorescence spectrum measured using a spectrofluorometer.

  Red light-emitting nanocrystalline particles are 665 nm or less, 663 nm or less, 660 nm or less, 658 nm or less, 655 nm or less, 653 nm or less, 651 nm or less, 650 nm or less, 647 nm or less, 645 nm or less, 643 nm or less, 640 nm or less, 637 nm or less, 635 nm or less. , 632 nm or less, or 630 nm or less, and preferably has an emission peak wavelength of 628 nm or more, 625 nm or more, 623 nm or more, 620 nm or more, 615 nm or more, 610 nm or more, 607 nm or more, or 605 nm or more. These upper and lower limits can be arbitrarily combined. In the following description, the upper limit and the lower limit individually described can be arbitrarily combined.

  The green-emitting nanocrystalline particles have an emission peak wavelength at 560 nm or less, 557 nm or less, 555 nm or less, 550 nm or less, 547 nm or less, 545 nm or less, 543 nm or less, 540 nm or less, 537 nm or less, 535 nm or less, 532 nm or less, or 530 nm or less. It is preferable that the emission peak wavelength be at least 528 nm, at least 525 nm, at least 523 nm, at least 520 nm, at least 515 nm, at least 510 nm, at least 507 nm, at least 505 nm, at least 503 nm, or at least 500 nm.

  The blue-emitting nanocrystalline particles have an emission peak wavelength at 480 nm or less, 477 nm or less, 475 nm or less, 470 nm or less, 467 nm or less, 465 nm or less, 463 nm or less, 460 nm or less, 457 nm or less, 455 nm or less, 452 nm or less, or 450 nm or less. It is preferable to have an emission peak wavelength at 450 nm or more, 445 nm or more, 440 nm or more, 435 nm or more, 430 nm or more, 428 nm or more, 425 nm or more, 422 nm or more, or 420 nm or more.

  According to the solution of the Schrodinger wave equation of the well-type potential model, the wavelength (emission color) of light emitted from the luminescent nanocrystal particles depends on the size (eg, particle diameter) of the luminescent nanocrystal particles. It also depends on the energy gap of the crystal grains. Therefore, the emission color can be selected by changing the constituent material and size of the luminescent nanocrystal particles used.

  The luminescent nanocrystal particles may be luminescent nanocrystal particles including a semiconductor material (luminescent semiconductor nanocrystal particles). Examples of the luminescent semiconductor nanocrystal particles include quantum dots and quantum rods. Among these, quantum dots are preferred from the viewpoint that emission spectrum can be easily controlled, reliability is secured, production costs are reduced, and mass productivity is improved.

  The light-emitting semiconductor nanocrystal particles may be composed of only the core containing the first semiconductor material, the core containing the first semiconductor material, and the second semiconductor material different from the first semiconductor material, And a shell covering at least a part of the core. In other words, the structure of the luminescent semiconductor nanocrystal particles may be a structure composed of only the core (core structure) or a structure composed of the core and the shell (core / shell structure). In addition, the luminescent semiconductor nanocrystal particles include a third semiconductor material different from the first and second semiconductor materials, in addition to the shell (first shell) including the second semiconductor material, and A shell (second shell) covering at least a part thereof may be further provided. In other words, the structure of the light-emitting semiconductor nanocrystal particles may be a structure including a core, a first shell, and a second shell (core / shell / shell structure). Each of the core and the shell may be a mixed crystal containing two or more semiconductor materials (for example, CdSe + CdS, CIS + ZnS, etc.).

  The luminescent nanocrystal particles are selected as a semiconductor material from the group consisting of II-VI semiconductors, III-V semiconductors, I-III-VI semiconductors, IV semiconductors, and I-II-IV-VI semiconductors. It is preferable to include at least one semiconductor material.

Specific semiconductor materials include CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeD, HgSed, HgSeTe, HgSeTe, HgSeC, ZnSe CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, CdHgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSZn, Al, ZnH, ZnH InP, InAs, InSb, GaNP, GaNAs, GaNSb, GaPAs, Ga Sb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInP, InP, InP, InP InAlPSb; SnS, SnSe, SnTe, PbS, PbSe, PbTe, SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe, SnPbTe, SnPbSSe, SnPbSeTe, SnPbSTe; Si, Ge, SiC, SiGe, AgInSe 2, CuGaSe _2, CuInS _2, CuG _{S 2, CuInSe 2, AgInS 2} , AgGaSe 2, AgGaS 2, C, include Si and Ge. The light-emitting semiconductor nanocrystal particles can easily control the emission spectrum, ensure reliability, reduce production costs, and improve mass productivity. From the viewpoint of improving mass productivity, CdS, CdSe, CdTe, ZnS, _{ZnSe, ZnTe, ZnO, HgS,} HgSe, HgTe, InP, InAs, InSb, GaP, GaAs, GaSb, AgInS 2, AgInSe 2, AgInTe 2, AgGaS 2, AgGaSe 2, AgGaTe 2, CuInS 2, CuInSe 2, CuInTe 2 , CuGaS ₂ , CuGaSe ₂ , CuGaTe ₂ , Si, C, Ge and at least one selected from the group consisting of Cu ₂ ZnSnS ₄ .

  The red-emitting semiconductor nanocrystal particles include, for example, CdSe nanocrystal particles and nanocrystal particles having a core / shell structure, in which the shell portion is CdS and the inner core portion is CdSe. Nanocrystal particles having a core / shell structure, wherein the shell portion is CdS and the inner core portion is ZnSe, a nanocrystal particle of a mixed crystal of CdSe and ZnS, a nanocrystal particle of InP. A crystalline particle, a nanocrystalline particle having a core / shell structure, wherein the shell portion is ZnS and the inner core portion is InP, a nanocrystalline particle having a core / shell structure, Nanocrystalline particles in which the shell portion is a mixed crystal of ZnS and ZnSe and the inner core portion is InP, nanocrystalline particles of a mixed crystal of CdSe and CdS, ZnSe and Cd And a nanocrystal particle having a core / shell / shell structure, wherein the first shell portion is ZnSe, the second shell portion is ZnS, and the inner core portion is A nanocrystal particle of InP, a nanocrystal particle having a core / shell / shell structure, wherein the first shell portion is a mixed crystal of ZnS and ZnSe, the second shell portion is ZnS, and And nanocrystalline particles whose core is InP.

  Examples of the green light-emitting semiconductor nanocrystal particles include CdSe nanocrystal particles, mixed crystal nanocrystal particles of CdSe and ZnS, and nanocrystal particles having a core / shell structure, wherein the shell portion is ZnS. And a nanocrystal particle having an inner core portion of InP and a nanocrystal particle having a core / shell structure, wherein the shell portion is a mixed crystal of ZnS and ZnSe and the inner core portion is InP. Nanocrystalline particles having a crystal particle, a core / shell / shell structure, wherein the first shell portion is ZnSe, the second shell portion is ZnS, and the inner core portion is InP. , A nanocrystal particle having a core / shell / shell structure, wherein the first shell portion is a mixed crystal of ZnS and ZnSe, the second shell portion is ZnS, and the inner core portion. Nanocrystalline particles or the like is InP and the like.

  The blue light emitting semiconductor nanocrystal particles include, for example, ZnSe nanocrystal particles, ZnS nanocrystal particles, and nanocrystal particles having a core / shell structure, wherein the shell portion is ZnSe and the inner core portion is Is a nanocrystal particle of ZnS, a nanocrystal particle of CdS, or a nanocrystal particle having a core / shell structure, wherein the shell portion is ZnS and the inner core portion is InP; A nanocrystalline particle having a structure in which the shell portion is a mixed crystal of ZnS and ZnSe and an inner core portion is InP, and a nanocrystalline particle having a core / shell / shell structure. The first shell portion is ZnSe, the second shell portion is ZnS, and the inner core portion is InP. And a nanocrystalline, a first shell portion is a mixed crystal of ZnS and ZnSe, a second shell portion is ZnS, include nanocrystalline like core portion of the inner is InP.

  By changing the average particle diameter of the semiconductor nanocrystal particles with the same chemical composition, the color to be emitted from the particles can be changed to red or green. In addition, it is preferable to use semiconductor nanocrystal particles which themselves have as low an adverse effect on the human body as possible. When semiconductor nanocrystal particles containing cadmium, selenium, etc. are used as the luminescent nanocrystal particles, the semiconductor nanocrystal particles containing as little as possible the above elements (cadmium, selenium, etc.) are selected and used alone, or Is preferably used in combination with other luminescent nanocrystal particles so as to minimize as much as possible.

  The shape of the luminescent nanocrystal particles is not particularly limited, and may be any geometric shape or any irregular shape. The shape of the luminescent nanocrystal particles may be, for example, a sphere, an ellipsoid, a pyramid, a disk, a branch, a net, a rod, and the like. However, the use of particles having a small directional shape (for example, particles having a spherical shape, a tetrahedral shape, or the like) as the luminescent nanocrystal particles can further enhance the uniformity and fluidity of the ink composition. Is preferred.

  The average particle diameter (volume average diameter) of the luminescent nanocrystal particles may be 1 nm or more, from the viewpoint of easily obtaining light emission of a desired wavelength, and from the viewpoint of excellent dispersibility and storage stability, and may be 1.5 nm or more. Or 2 nm or more. From the viewpoint of easily obtaining a desired emission wavelength, the wavelength may be 40 nm or less, 30 nm or less, or 20 nm or less. The average particle diameter (volume average diameter) of the luminescent nanocrystal particles can be obtained by measuring with a transmission electron microscope or a scanning electron microscope and calculating the volume average diameter.

  The luminescent nanocrystal particles preferably have an organic ligand on the surface from the viewpoint of dispersion stability. The organic ligand may, for example, be coordinated to the surface of the luminescent nanocrystal particle. In other words, the surface of the luminescent nanocrystal particles may be passivated by the organic ligand. When the ink composition further contains a polymer dispersant described below, the luminescent nanocrystalline particles may have a polymer dispersant on the surface. In the present embodiment, for example, by removing the organic ligand from the luminescent nanocrystal particles having the organic ligand described above, by exchanging the organic ligand and the polymer dispersant, the polymer dispersant on the surface of the luminescent nanocrystal particles May be combined. However, from the viewpoint of dispersion stability when formed into an ink-jet ink, it is preferable that a polymer dispersant is blended with the luminescent nanocrystal particles in which the organic ligand is coordinated.

  As the organic ligand, a functional group (hereinafter, also simply referred to as an “affinity group”) for securing an affinity with a photopolymerizable compound, an organic solvent, and the like, and a functional group capable of binding to the luminescent nanocrystal particles (A functional group for ensuring the adsorptivity to the luminescent nanocrystal particles). The affinity group may be a substituted or unsubstituted aliphatic hydrocarbon group. The aliphatic hydrocarbon group may be linear or may have a branched structure. Further, the aliphatic hydrocarbon group may have an unsaturated bond or may not have an unsaturated bond. The substituted aliphatic hydrocarbon may be a group in which some carbon atoms of the aliphatic hydrocarbon group have been substituted with oxygen atoms. The substituted aliphatic hydrocarbon group may include, for example, a (poly) oxyalkylene group. Here, the “(poly) oxyalkylene group” means at least one of an oxyalkylene group and a polyoxyalkylene group in which two or more alkylene groups are connected by an ether bond. Examples of the functional group capable of binding to the luminescent nanocrystal particles include a hydroxyl group, an amino group, a carboxyl group, a thiol group, a phosphoric acid group, a phosphonic acid group, a phosphine group, a phosphine oxide group, and an alkoxysilyl group. Examples of the organic ligand include TOP (trioctylphosphine), TOPO (trioctylphosphine oxide), oleic acid, oleylamine, octylamine, trioctylamine, hexadecylamine, octanethiol, dodecanethiol, and hexylphosphonic acid (HPA). , Tetradecylphosphonic acid (TDPA), and octylphosphinic acid (OPA).

  The organic ligand preferably has a main chain containing a polyoxyalkylene group, and at least one terminal of the main chain has one or more functional groups capable of binding to the luminescent nanocrystal particles. Examples of the polyoxyalkylene group contained in the main chain include a polyoxyethylene group and a polyoxypropylene group. The main chain has, for example, a substituted or unsubstituted hydrocarbon group in addition to the polyoxyalkylene group. The functional group is, for example, a group capable of coordinating with a luminescent nanocrystal particle. The functional group may include, for example, a functional group capable of binding to the above-described luminescent nanocrystal particles. Here, the main chain refers to the longest molecular chain constituting the compound. The substituted or unsubstituted hydrocarbon group may have, for example, 1 to 10 carbon atoms. In the substituted hydrocarbon group, a part of carbon atoms may be substituted with a hetero atom such as a sulfur atom or a nitrogen atom, a carbonyl group or the like.

  The organic ligand has one or more first functional groups capable of binding to the luminescent nanocrystal particles at one end of the main chain, and a second functional group different from the first functional group at the other end of the main chain. It may have a group. The first functional group may be the same as the group described above as the functional group capable of binding to the luminescent nanocrystal particles. The number of the first functional groups may be one or more, two or more, or two. The second functional group may be the same as the group described above as the functional group capable of binding to the luminescent nanocrystal particles, or may be another group different from the functional group. Other groups may be, for example, a cycloalkyl group or an aryl group. The number of the second functional groups may be one or more, and may be one.

［式（１−１）中、ｐは０〜５０の整数を示し、ｑは０〜５０の整数を示す。］ In one embodiment, the organic ligand may be an organic ligand represented by the following formula (1-1).

[In formula (1-1), p represents an integer of 0 to 50, and q represents an integer of 0 to 50. ]

  In the organic ligand represented by the formula (1-1), at least one of p and q is preferably 1 or more, and more preferably both p and q are 1 or more.

  In one embodiment, the first functional group is a carboxyl group, the second functional group is a hydroxyl group, and the organic ligand may have two or more first functional groups. That is, in one embodiment, the organic ligand may have one or more carboxyl groups at one end of the main chain, may have a hydroxyl group at the other end of the main chain, and may have a carboxyl group at one end of the main chain. It may have two or more groups and may have a hydroxyl group at the other end of the main chain.

The organic ligand may be, for example, an organic ligand represented by the following formula (1-2).

In the formula (1-2), A ¹ represents a monovalent group containing a carboxyl group, A ² represents a monovalent group containing a hydroxyl group, and R represents a hydrogen atom, a methyl group, or an ethyl group. L represents a substituted or unsubstituted alkylene group, and r represents an integer of 0 or more. The number of carboxyl groups in the monovalent group containing a carboxyl group may be two or more, may be two or more and four or less, and may be two. The carbon number of the alkylene group represented by L may be, for example, 1 to 10. In the alkylene group represented by L, part of carbon atoms may be substituted with a hetero atom, and at least one hetero atom selected from the group consisting of an oxygen atom, a sulfur atom and a nitrogen atom is used. Is also good. r may be, for example, an integer of 1 to 100 or an integer of 10 to 20.

The organic ligand is preferably an organic ligand represented by the following formula (1-2A).

  In the formula (1-2A), r has the same meaning as described above.

  The organic ligand is desirably an organic ligand represented by the formula (1-2A) from the viewpoint of excellent external quantum efficiency of the pixel portion and its maintenance rate.

  As the luminescent nanocrystal particles, those dispersed in a colloidal form in an organic solvent, a photopolymerizable compound, or the like can be used. The surface of the luminescent nanocrystal particles dispersed in the organic solvent is preferably passivated by the above-mentioned organic ligand. Examples of the organic solvent include cyclohexane, hexane, heptane, chloroform, toluene, octane, chlorobenzene, tetralin, diphenyl ether, propylene glycol monomethyl ether acetate, butyl carbitol acetate, 1,4-butanediol diacetate, and mixtures thereof. No.

  Commercial products can be used as the luminescent nanocrystal particles. Commercially available luminescent nanocrystalline particles include, for example, indium phosphide / zinc sulfide, D-dot, CuInS / ZnS, and AlPrich's InP / ZnS from NN-Labos.

  The content of the luminescent nanocrystal particles is preferably more than 20% by mass, more preferably 23% by mass, based on the mass of the non-volatile content of the ink composition, from the viewpoint of improving the effect of maintaining the external quantum efficiency. %, More preferably 25% by mass or more. When the content of the luminescent nanocrystal particles is more than 20% by mass, excellent luminescence intensity is obtained, and thus such an ink composition is suitably used for a color filter. From the same viewpoint, the content of the luminescent nanocrystal particles may be 50% by mass or less, 40% by mass or less, or 35% by mass or less based on the mass of the nonvolatile components of the ink composition. And may be 30% by mass or less. The content of the luminescent nanocrystal particles is 50% by mass or less based on the mass of the nonvolatile components of the ink composition from the viewpoint of more excellent ejection stability. In addition, when the content of the luminescent nanocrystal particles is 50% by mass or less, excellent luminescence intensity is obtained, and thus such an ink composition is suitably used as an inkjet ink for a color filter. From the same viewpoint, the content of the luminescent nanocrystal particles may be 40% by mass or less, 35% by mass or less, or 30% by mass, based on the mass of the nonvolatile components of the ink composition. It may be as follows. The content of the luminescent nanocrystal particles is, for example, more than 20% by mass and 50% by mass or less, 23 to 50% by mass, 25 to 50% by mass, and more than 20% by mass, based on the mass of the non-volatile content of the ink composition. It may be not more than 20% by mass, not more than 20% by mass and not more than 35% by mass, or more than 20% by mass and not more than 30% by mass. In the present specification, the "mass of non-volatile components of the ink composition", when the ink composition contains a solvent, refers to the mass excluding the mass of the solvent from the total mass of the ink composition, the ink composition When no solvent is contained, it refers to the total weight of the ink composition.

  The ink composition may contain two or more of red light-emitting nanocrystal particles, green light-emitting nanocrystal particles, and blue light-emitting nanocrystal particles as light-emitting nanocrystal particles, but preferably these are used. Contains only one of the particles. When the ink composition contains red luminescent nanocrystal particles, the content of the green luminescent nanocrystal particles and the content of the blue luminescent nanocrystal particles are preferably 10%, based on the total mass of the luminescent nanocrystal particles. %, More preferably 0% by mass. When the ink composition contains green light-emitting nanocrystal particles, the content of red light-emitting nanocrystal particles and the content of blue light-emitting nanocrystal particles are preferably 10%, based on the total mass of the light-emitting nanocrystal particles. %, More preferably 0% by mass.

[Photopolymerizable compound]
The ink composition of the present embodiment has, as a photopolymerizable compound, an allyl ether group (—O—CH ₂ —CH ₂ ＣＨCH ₂ ) and an ethylenic group that can react with the allyl ether group to form an intramolecular ring. A photopolymerizable compound containing an unsaturated group (hereinafter, also referred to as a “first photopolymerizable compound”). In this specification, an ethylenically unsaturated group means a group having an ethylenically unsaturated bond (polymerizable carbon-carbon double bond).

  Here, the “photopolymerizable compound” means a compound that is polymerized by irradiation with light (active energy ray). The photopolymerizable compound is typically used together with a photopolymerization initiator described below. For example, a photo-radical polymerizable compound is used together with a photo-radical polymerization initiator. In other words, the ink composition of this embodiment may contain a photopolymerizable compound (for example, a photoradical polymerizable compound) and a photopolymerizable component including a photopolymerization initiator (for example, a photoradical polymerization initiator).

  The intramolecular cyclization reaction between the allyl ether group and the ethylenically unsaturated group in the first photopolymerizable compound may be an intramolecular radical cyclization reaction. In the intramolecular radical cyclization reaction, the ethylenically unsaturated group and the allyl ether group undergo a radical reaction to form a carbon-carbon bond between the ethylenically unsaturated bonds, thereby forming an intramolecular ring ( (An ether ring) is formed. Therefore, by subjecting the first photopolymerizable compound to radical polymerization, the intramolecular cyclization reaction and the polymerization reaction proceed almost simultaneously, and a polymer having a structural unit containing an ether ring is obtained.

  The structure of the formed intramolecular ring may be, for example, a four-membered ring structure (eg, a tetrahydrofuran structure), a five-membered ring structure, or a six-membered ring structure, preferably a five-membered ring structure. The positional relationship between the allyl ether group and the ethylenically unsaturated group that reacts with the allyl ether group in the first photopolymerizable compound may be a positional relationship capable of forming such an intramolecular ring.

［式（Ｉ）中、Ｘは水素原子又は一価の有機基を示し、Ｙは二価の炭化水素基を示す。Ａで示す点線で囲われた部分はアリルエーテル基中のエチレン性不飽和結合を示し、Ｂで示す点線で囲われた部分は当該アリルエーテル基と反応して分子内環を形成しうるエチレン性不飽和基中のエチレン性不飽和結合を示す。］ The allyl ether group and the ethylenically unsaturated group capable of forming an inner ring by reacting with the allyl ether group may be linked by a divalent hydrocarbon group. That is, the first photopolymerizable compound may be a compound represented by the following formula (I).

[In the formula (I), X represents a hydrogen atom or a monovalent organic group, and Y represents a divalent hydrocarbon group. The portion enclosed by the dotted line indicated by A indicates an ethylenically unsaturated bond in the allyl ether group, and the portion enclosed by the dotted line indicated by B indicates an ethylenic group capable of reacting with the allyl ether group to form an intramolecular ring. Indicates an ethylenically unsaturated bond in an unsaturated group. ]

  The divalent hydrocarbon group Y is, for example, an alkylene group, preferably a methylene group.

［式（ＩＩ）中、＊は結合手を示す。］ The ethylenically unsaturated group capable of forming an intramolecular ring by reacting with an allyl ether group may be, for example, an ethylenically unsaturated group contained in a structure represented by the following formula (II). That is, the first photopolymerizable compound may include a structure represented by the following formula (II) as a structure having an ethylenically unsaturated group capable of forming an intramolecular ring by reacting with an allyl ether group. .

[In formula (II), * represents a bond. ]

［式（ＩＩａ）中、＊は結合手を示し、Ｒ^１は炭化水素基を示す。］

［式（ＩＩＩ）中、＊は結合手を示し、Ｒ^１は炭化水素基を示す。］ The structure represented by the formula (II) is preferably a structure represented by the following formula (IIa). That is, X in the formula (I) is preferably a group represented by the following formula (III).

[In formula (IIa), * represents a bond, and R ¹ represents a hydrocarbon group. ]

[In the formula (III), * represents a bond, and R ¹ represents a hydrocarbon group. ]

The carbon number of R ¹ (the carbon number of the hydrocarbon group) is not particularly limited, and is, for example, 1 to 4. R ¹ may be a substituted or unsubstituted aliphatic hydrocarbon group. R ¹ is preferably an alkyl group, more preferably a methyl group.

［式（Ｉａ）中、Ｒ^２はアルキル基を示す。］ The first photopolymerizable compound is preferably alkyl 2-allyloxymethyl acrylate from the viewpoint of obtaining more excellent ejection stability and obtaining more excellent external quantum efficiency maintaining performance. That is, the first photopolymerizable compound is preferably a compound represented by the following formula (Ia).

[In the formula (Ia), R ² represents an alkyl group. ]

R ² in formula (Ia) is preferably a methyl group. That is, the first photopolymerizable compound is more preferably methyl 2-allyloxymethyl acrylate.

  The number of ethylenically unsaturated bonds (the number of ethylenically unsaturated groups) of the first photopolymerizable compound is preferably 2 from the viewpoint of suppressing the progress of a side reaction during an intramolecular cyclization reaction. That is, X and Y in the formula (I) preferably do not contain an ethylenically unsaturated bond.

  The molecular weight of the first photopolymerizable compound is preferably 300 or less, more preferably 250 or less, and still more preferably 200 or less, from the viewpoint of excellent ejection stability of the ink composition. The molecular weight of the first photopolymerizable compound may be 150 or more, 200 or more, or 250 or more.

  The viscosity of the first photopolymerizable compound is preferably 20 mPa · s or less, more preferably 12 mPa · s or less, from the viewpoint of excellent ejection stability of the ink composition. The viscosity of the first photopolymerizable compound may be 1.5 mPa · s or more, 2.9 mPa · s or more, or 5.3 mPa · s or more.

  Conventionally, a low-viscosity photopolymerizable compound such as (meth) acrylate has been studied as a photopolymerizable compound for an inkjet ink from the viewpoint of improving the ejection stability required for the inkjet ink. However, it has been difficult for these photopolymerizable compounds to achieve both excellent ejection stability and excellent optical properties (external quantum efficiency, external quantum efficiency maintaining performance, etc.). In contrast, the first photopolymerizable compound tends to have a low viscosity before polymerization (before curing), and after polymerization (after curing), the polymer of the above-mentioned conventional photopolymerizable compound A stronger molecular structure can be obtained as compared with. Therefore, the use of the first photopolymerizable compound tends to easily achieve both excellent ejection stability and excellent optical characteristics (external quantum efficiency, performance for maintaining external quantum efficiency, and the like). .

  The content of the first photopolymerizable compound is determined from the viewpoint that an appropriate viscosity is easily obtained as an inkjet ink, the viewpoint that the pixel portion (cured product of the ink composition) is more excellent in maintaining the external quantum efficiency, and the content of the pixel portion ( 5% by mass or more, 10% by mass or more, 15% by mass or more, 20% by mass or more based on the mass of the nonvolatile components of the ink composition, from the viewpoint of improving the solvent resistance and abrasion resistance of the cured product of the ink composition). As described above, it may be 25% by mass or more, 30% by mass or more, 35% by mass or more, or 40% by mass or more. The content of the first photopolymerizable compound is determined based on the viewpoint that an appropriate viscosity is easily obtained as an inkjet ink and that the pixel portion (cured product of the ink composition) is more excellent in maintaining the external quantum efficiency. It may be 70% by mass or less, 60% by mass or less, 50% by mass or less, 40% by mass or less, 30% by mass or less, or 20% by mass or less based on the mass of the non-volatile content of the product. The content of the first photopolymerizable compound is, for example, 5 to 70% by mass, 10 to 70% by mass, 15 to 70% by mass, 25 to 70% by mass, based on the mass of the nonvolatile components of the ink composition. It may be 30 to 60% by mass, 35 to 60% by mass, 35 to 50% by mass or 40 to 50% by mass.

  As the first photopolymerizable compound, one type may be used alone, or two or more types may be used in combination. Further, the ink composition may contain, as the photopolymerizable compound, a second photopolymerizable compound different from the first photopolymerizable compound. The second photopolymerizable compound contained in the ink composition may be one type or a plurality of types.

  Examples of the second photopolymerizable compound include a monomer having an ethylenically unsaturated group. Here, the ethylenically unsaturated monomer means a monomer having an ethylenically unsaturated bond (carbon-carbon double bond). Examples of the monomer having an ethylenically unsaturated group include monomers having an ethylenically unsaturated group such as a vinyl group, a vinylene group, a vinylidene group, and a (meth) acryloyl group. From the viewpoint of further improving the external quantum efficiency, monofunctional or bifunctional (meth) acrylates are more preferable from the viewpoint of further improving the performance of maintaining the external quantum efficiency of monofunctional or bifunctional (meth) acrylates. In this specification, “(meth) acryloyl group” means “acryloyl group” and the corresponding “methacryloyl group”. The same applies to the expressions “(meth) acrylate” and “(meth) acrylamide”. Monofunctional (meth) acrylate means a (meth) acrylate monomer having one (meth) acryloyl group, and polyfunctional (meth) acrylate has two or more (meth) acryloyl groups. It means a (meth) acrylate monomer.

  The number of ethylenically unsaturated bonds (for example, the number of ethylenically unsaturated groups) in the ethylenically unsaturated monomer is, for example, 1 to 3. From the viewpoint of obtaining more excellent ejection stability, and from the viewpoint of obtaining more excellent performance of maintaining external quantum efficiency, a polyfunctional unsaturated monomer having two or more ethylenically unsaturated bonds is preferable, and two or more ( A polyfunctional (meth) acrylate having a (meth) acryloyl group is more preferable, and a polyfunctional acrylate having two or more acryloyl groups is more preferable. As the polyfunctional (meth) acrylate, bifunctional (meth) acrylates such as alkylene glycol di (meth) acrylate and polyalkylene glycol di (meth) acrylate are preferable, and bifunctional acrylate is more preferable.

  Specific examples of the polyfunctional (meth) acrylate include 1,3-butylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, 1,5-pentanediol di (meth) acrylate, Methyl-1,5-pentanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1,8-octanediol di (meth) acrylate, 1,9 -Nonanediol di (meth) acrylate, tricyclodecane dimethanol di (meth) acrylate, ethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate ) Acrylate, The two hydroxyl groups of propylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, neopentyl glycol hydroxypivalate acrylate, and tris (2-hydroxyethyl) isocyanurate are represented by (meth) Di (meth) acrylate substituted with an acryloyloxy group, two hydroxyl groups of a diol obtained by adding 4 mol or more of ethylene oxide or propylene oxide to 1 mol of neopentyl glycol are substituted with a (meth) acryloyloxy group. Di (meth) acrylate or di (meth) acrylate in which two hydroxyl groups of a diol obtained by adding 2 mol of ethylene oxide or propylene oxide to 1 mol of bisphenol A are substituted by (meth) acryloyloxy group. 1) A mole of di (meth) acrylate or bisphenol A in which two hydroxyl groups of a triol obtained by adding 3 moles or more of ethylene oxide or propylene oxide to 1 mole of acrylate or trimethylolpropane are substituted with (meth) acryloyloxy groups. A difunctional (meth) acrylate such as di (meth) acrylate in which two hydroxyl groups of a diol obtained by adding 4 mol or more of ethylene oxide or propylene oxide to a (meth) acryloyloxy group, glycerin tri ( Examples include trifunctional (meth) acrylates such as (meth) acrylate and trimethylolethane tri (meth) acrylate. Of these, alkylene glycol di (meth) acrylates having 4 to 12 carbon atoms in the alkylene group are preferable, and examples thereof include 1,4-butanediol di (meth) acrylate and 1,6-hexanediol di (meth) acrylate. It is preferably used.

  The second photopolymerizable compound may be a monofunctional (meth) acrylate. Examples of the monofunctional (meth) acrylate include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, amyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and octyl. (Meth) acrylate, nonyl (meth) acrylate, dodecyl (meth) acrylate, hexadecyl (meth) acrylate, octadecyl (meth) acrylate, cyclohexyl (meth) acrylate, methoxyethyl (meth) acrylate, butoxyethyl (meth) acrylate, phenoxy Ethyl (meth) acrylate, nonylphenoxyethyl (meth) acrylate, glycidyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, diethylaminoethyl (Meth) acrylate, ethoxyethoxyethyl (meth) acrylate, isobornyl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, dicyclopentenyloxyethyl (meth) acrylate, 2-hydroxy- 3-phenoxypropyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, benzyl (meth) acrylate, phenylbenzyl (meth) acrylate, mono (2-acryloyloxyethyl) succinate, N- [2- (acryloyloxy) ethyl] phthalimide, N- [2- (acryloyloxy) ethyl] tetrahydrophthalimide and the like can be mentioned.

  The content of the second photopolymerizable compound is determined from the viewpoint that an appropriate viscosity is easily obtained as an inkjet ink, the viewpoint that the pixel portion (cured product of the ink composition) is more excellent in the performance of maintaining the external quantum efficiency, and the pixel portion ( From the viewpoint of improving the solvent resistance and abrasion resistance of the cured product of the ink composition), the content is 5% by mass or more, 10% by mass or more, or 15% by mass or more based on the mass of the nonvolatile components of the ink composition. Good. The content of the second photopolymerizable compound is determined from the viewpoint that an appropriate viscosity is easily obtained as an ink-jet ink and the viewpoint that the pixel portion (cured product of the ink composition) is more excellent in the performance of maintaining the external quantum efficiency. It may be 30% by mass or less, 20% by mass or less, or 25% by mass or less based on the mass of the non-volatile content of the product.

  The ratio of the content of the second photopolymerizable compound to the content of the first photopolymerizable compound (the content of the second photopolymerizable compound / the content of the first photopolymerizable compound) is determined in the pixel portion. From the viewpoint of better performance of maintaining the external quantum efficiency of the (cured product of the ink composition), for example, it may be 0.3 or more, 0.4 or more, or 0.5 or more, 0.8 or less, 0.7 or less Or it may be 0.6 or less.

  The content of all the photopolymerizable compounds (the total amount of the first photopolymerizable compound and the second photopolymerizable compound) contained in the ink composition is outside the pixel portion (the cured product of the ink composition). From the viewpoint of better quantum efficiency maintenance performance, for example, 5% by mass or more, 10% by mass or more, 15% by mass or more, 20% by mass or more, 25% by mass or more, 30% by mass or more, 35% by mass or more, 40% by mass or more Or less than 45% by mass, and may be 70% by mass or less, 60% by mass or less, 50% by mass or less, 40% by mass or less, 30% by mass or less, or 20% by mass or less.

  The photopolymerizable compound used in the present embodiment may be alkali-insoluble from the viewpoint of easily obtaining a highly reliable pixel portion (a cured product of the ink composition). In the present specification, the term “photopolymerizable compound is alkali-insoluble” means that the amount of the photopolymerizable compound dissolved in a 1% by mass aqueous potassium hydroxide solution at 25 ° C. is 30% based on the total mass of the photopolymerizable compound. % By mass or less. The dissolution amount of the photopolymerizable compound is preferably 10% by mass or less, more preferably 3% by mass or less.

  The above-mentioned photopolymerizable compound may be used as a mixture with a polymerization inhibitor. Examples of the polymerization inhibitor include 4-hydroxy-2,2,6,6-tetramethylpiperidinooxy and free radicals. The amount of the polymerization inhibitor used may be an amount that does not inhibit the polymerization of the photopolymerizable compound at the time of forming the pixel portion, and is, for example, 0.05 to 0.10 with respect to 100 parts by mass of the photopolymerizable compound. Parts by weight.

[Photopolymerization initiator]
The photopolymerization initiator is, for example, a photoradical polymerization initiator. As the photo radical polymerization initiator, a molecular cleavage type or hydrogen abstraction type photo radical polymerization initiator is suitable.

  Examples of the molecular cleavage type photoradical polymerization initiator include benzoin isobutyl ether, 2,4-diethylthioxanthone, 2-isopropylthioxanthone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, and 2-benzyl-2-dimethylamino-1. -(4-morpholinophenyl) -butan-1-one, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, (2,4,6-trimethylbenzoyl) ethoxyphenylphosphine oxide Etc. are preferably used. Other than these, as a molecular cleavage type photoradical polymerization initiator, 1-hydroxycyclohexyl phenyl ketone, benzoin ethyl ether, benzyl dimethyl ketal, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1- (4 -Isopropylphenyl) -2-hydroxy-2-methylpropan-1-one and 2-methyl-1- (4-methylthiophenyl) -2-morpholinopropan-1-one may be used in combination.

  Examples of the hydrogen abstraction type photoradical polymerization initiator include benzophenone, 4-phenylbenzophenone, isophthalphenone, 4-benzoyl-4'-methyl-diphenyl sulfide, and the like. A molecular cleavage type photoradical polymerization initiator and a hydrogen abstraction type photoradical polymerization initiator may be used in combination.

  In this embodiment, from the viewpoint of obtaining excellent external quantum efficiency, the ink composition may include a photopolymerization initiator having a molecular weight of 350 or less as the photopolymerization initiator. In particular, when the content of the luminescent nanocrystal particles is more than 20% by mass and 50% by mass or less based on the mass of the non-volatile content of the ink composition, the ink composition starts photopolymerization having a molecular weight of 350 or less. It is preferable to include an agent.

  The molecular weight of the photopolymerization initiator is preferably 330 or less from the viewpoint of improving the external quantum efficiency, and from the viewpoint of easily achieving both ejection stability and curability. The molecular weight of the photopolymerization initiator is preferably 150 or more, more preferably 200 or more, and further preferably 250 or more, from the viewpoint of improving the external quantum efficiency, and from the viewpoint of easily achieving both ejection stability and curability. And more preferably 300 or more. From these viewpoints, the molecular weight of the photopolymerization initiator may be 150 to 350, 200 to 350, 250 to 350, 300 to 350, 150 to 330, 200 to 330, 250 to 330, or 300 to 330. Although the ink composition may contain a photopolymerization initiator having a molecular weight of more than 350, the content of the photopolymerization initiator having a molecular weight of 350 or less in the total amount of the photopolymerization initiator is preferably 1% by mass. Or more, more preferably 2% by mass or more. In the total amount of the photopolymerization initiator, the content of the photopolymerization initiator having a molecular weight of 350 or less may be 50% by mass or more, 70% by mass or more, or 90% by mass or more. The content of the photopolymerization initiator having a molecular weight of 350 or less may be 100% by mass.

  From the viewpoint of curability of the ink composition, the content of the photopolymerization initiator may be 0.1 part by mass or more, and may be 0.5 part by mass or more based on 100 parts by mass of the photopolymerizable compound. The amount may be 1 part by mass or more, 3 parts by mass or more, or 5 parts by mass or more. The content of the photopolymerization initiator may be 40 parts by mass or less based on 100 parts by mass of the photopolymerizable compound from the viewpoint of the temporal stability of the pixel portion (cured product of the ink composition), and may be 30 parts by mass. Or less, may be 20 parts by mass or less, or may be 10 parts by mass or less.

[Light scattering particles]
The light scattering particles are, for example, optically inactive inorganic fine particles. When the ink composition contains light-scattering particles, light from a light source applied to the pixel portion can be scattered, so that excellent optical characteristics can be obtained.

  As a material constituting the light scattering particles, for example, a single metal such as tungsten, zirconium, titanium, platinum, bismuth, rhodium, palladium, silver, tin, platinum, and gold; silica, barium sulfate, barium carbonate, calcium carbonate, Metal oxides such as talc, clay, kaolin, barium sulfate, barium carbonate, calcium carbonate, alumina white, titanium oxide, magnesium oxide, barium oxide, aluminum oxide, bismuth oxide, zirconium oxide, zinc oxide; magnesium carbonate, barium carbonate, Metal carbonates such as bismuth subcarbonate and calcium carbonate; metal hydroxides such as aluminum hydroxide; composite oxides such as barium zirconate, calcium zirconate, calcium titanate, barium titanate and strontium titanate; bismuth subnitrate Etc. metal And the like. The light-scattering particles are selected from the group consisting of titanium oxide, alumina, zirconium oxide, zinc oxide, calcium carbonate, barium sulfate, barium titanate and silica, from the viewpoint of excellent ejection stability and the effect of improving external quantum efficiency. Preferably, at least one selected from the group consisting of titanium oxide, zirconium oxide, zinc oxide and barium titanate is contained.

  The shape of the light-scattering particles may be spherical, filamentous, irregular, or the like. However, as the light-scattering particles, it is preferable to use particles having a small directionality (for example, particles having a spherical shape, a tetrahedral shape, or the like) as the particle shape, so that the uniformity, the fluidity, and the light scattering property of the ink composition are improved. This is preferable in that it can enhance the discharge stability.

  The light scattering particles may have at least a part of the surface covered with alumina. For example, 50% by area or more of the surface of the light scattering particles may be covered with alumina, and the entire surface of the light scattering particles may be covered with alumina. In this case, the light scattering particles can be rephrased as light scattering particles surface-treated with alumina.

  As a method of covering at least a part of the surface of the light-scattering particles with alumina (surface-treating with alumina), for example, a wet treatment method (neutralizing the solution by adding an aluminum salt aqueous solution to the light-scattering particle slurry) For adsorbing to the surface of the light scattering particles). As the light scattering particles, for example, “MPT-141”, “CR-50”, “CR-50-2”, “CR-58”, “CR-58-2”, “CR It is also possible to use commercially available products such as "-60", "CR-60-2", and "JR405", "JR603", "JR605", "JR701", and "JR806" manufactured by Teica Corporation. The surface of the light-scattering particles may be covered with alumina and other components such as silica, zinc oxide, titanium oxide, zirconium oxide, and organic substances such as stearic acid and polysiloxane.

  The average particle diameter (volume average diameter) of the light-scattering particles in the ink composition may be 0.05 μm (50 nm) or more from the viewpoint of excellent ejection stability and the effect of improving external quantum efficiency. , 0.2 μm (200 nm) or more, and 0.3 μm (300 nm) or more. The average particle diameter (volume average diameter) of the light-scattering particles in the ink composition may be 1.0 μm (1000 nm) or less, or 0.6 μm (600 nm) or less from the viewpoint of excellent ejection stability. And may be 0.4 μm (400 nm) or less. The average particle diameter (volume average diameter) of the light scattering particles in the ink composition is 0.05 to 1.0 μm, 0.05 to 0.6 μm, 0.05 to 0.4 μm, 0.2 to 1 μm. 0.0 μm, 0.2 to 0.6 μm, 0.2 to 0.4 μm, 0.3 to 1.0 μm, 0.3 to 0.6 μm, or 0.3 to 0.4 μm. From the viewpoint of easily obtaining such an average particle diameter (volume average diameter), the average particle diameter (volume average diameter) of the light-scattering particles used may be 0.05 μm or more and 1.0 μm or less. You may. In the present specification, the average particle diameter (volume average diameter) of the light-scattering particles in the ink composition is obtained by measuring with a dynamic light-scattering nanotrack particle size distribution analyzer and calculating the volume average diameter. . The average particle diameter (volume average diameter) of the light-scattering particles to be used is obtained by measuring the particle diameter of each particle with a transmission electron microscope or a scanning electron microscope, for example, and calculating the volume average diameter.

  The content of the light-scattering particles in the ink composition may be 0.1% by mass or more based on the mass of the non-volatile content of the ink composition from the viewpoint of being more excellent in the effect of improving the external quantum efficiency, and may be 1% by mass. Or more, 5% or more, 7% or more, 10% or more, and 12% or more. The content of the light-scattering particles may be 60% by mass or less, based on the mass of the non-volatile content of the ink composition, from the viewpoint of excellent ejection stability and the effect of improving external quantum efficiency. % Or less, 40% by weight or less, 30% by weight or less, 25% by weight or less, 20% by weight or less, 15% by weight %. When the ink composition contains a polymer dispersant, even when the content of the light-scattering particles is relatively large (for example, about 60% by mass), the light-scattering particles can be dispersed well. it can.

  The mass ratio of the content of the light-scattering particles to the content of the light-emitting nanocrystal particles (light-scattering particles / light-emitting nanocrystal particles) is 0.1 or more from the viewpoint of excellent effect of improving external quantum efficiency. And may be 0.2 or more, or 0.5 or more. The mass ratio (light scattering particles / luminous nanocrystal particles) may be 5.0 or less from the viewpoint of excellent external quantum efficiency improvement effect and excellent continuous dischargeability (discharge stability) during inkjet printing. , 2.0 or less, or 1.5 or less.

  The content of the inorganic component in the ink composition (for example, the total amount of the luminescent nanocrystal particles and the light-scattering particles) is determined based on the mass of the nonvolatile component of the ink composition from the viewpoint that an appropriate viscosity is easily obtained as an inkjet ink. As a reference, it is preferably at least 30% by mass, more preferably at least 40% by mass, and still more preferably at least 45% by mass. The content of the inorganic component in the ink composition (for example, the total amount of the luminescent nanocrystal particles and the light-scattering particles) is determined based on the mass of the nonvolatile component of the ink composition from the viewpoint that an appropriate viscosity is easily obtained as an inkjet ink. As a reference, it is preferably 70% by mass or less, more preferably 65% by mass or more, and further preferably 60% by mass or less. The content of the inorganic component (for example, the total amount of the luminescent nanocrystal particles and the light-scattering particles) in the ink composition may be 30 to 70% by mass, 40 to 65% by mass, or 45 to 60% by mass. .

  The ink composition may further contain other components other than the above-described components as long as the effects of the present invention are not impaired. Other components include, for example, a polymer dispersant, a solvent, an antioxidant, a thiol compound, and the like.

[Polymer dispersant]
The polymer dispersant is a polymer compound having a weight average molecular weight of 750 or more and having a functional group having an affinity for the light scattering particles. The polymer dispersant has a function of dispersing the light scattering particles. The polymer dispersant adsorbs to the light-scattering particles through a functional group having an affinity for the light-scattering particles, and the light-scattering particles are formed by electrostatic repulsion and / or steric repulsion between the polymer dispersants. Disperse in the ink composition. The polymer dispersant is preferably bonded to the surface of the light-scattering particles and adsorbed to the light-scattering particles, but is preferably bonded to the surface of the light-emitting nanocrystal particles and adsorbed to the light-emitting nanoparticles. And may be free in the ink composition.

  By the way, aggregation of light-emitting nanocrystal particles and light-scattering particles is considered as one of the causes of a decrease in ejection stability when a pixel portion is formed by an inkjet method using a conventional ink composition. Therefore, it is conceivable to improve the ejection stability by reducing the size of the luminescent nanocrystal particles and the light scattering particles, reducing the content of the luminescent nanocrystal particles and the light scattering particles, and the like. In this case, the effect of improving the external quantum efficiency tends to decrease, and it is difficult to achieve both excellent ejection stability and excellent external quantum efficiency. On the other hand, according to the ink composition further containing the polymer dispersant, it is possible to achieve both excellent ejection stability and excellent external quantum efficiency. The reason why such an effect is obtained is not clear, but is because the aggregation of the luminescent nanocrystal particles and the light-scattering particles (particularly, the light-scattering particles) is significantly suppressed by the polymer dispersant. It is inferred.

  Examples of the functional group having an affinity for the light-scattering particles include an acidic functional group, a basic functional group, and a nonionic functional group. The acidic functional group has a dissociable proton, and may be neutralized with a base such as an amine or a hydroxide ion.The basic functional group is neutralized with an acid such as an organic acid or an inorganic acid. You may.

Examples of the acidic functional group include a carboxyl group (—COOH), a sulfo group (—SO ₃ H), a sulfate group (—OSO ₃ H), a phosphonic acid group (—PO (OH) ₃ ), and a phosphate group (—OPO ( OH) ₃ ), a phosphinic acid group (—PO (OH) —), and a mercapto group (—SH).

  Examples of the basic functional group include primary, secondary, and tertiary amino groups, ammonium groups, imino groups, and nitrogen-containing heterocyclic groups such as pyridine, pyrimidine, pyrazine, imidazole, and triazole.

Examples of the nonionic functional group include a hydroxy group, an ether group, a thioether group, a sulfinyl group (—SO—), a sulfonyl group (—SO ₂ —), a carbonyl group, a formyl group, an ester group, a carbonate ester group, an amide group, Examples include carbamoyl, ureido, thioamide, thioureido, sulfamoyl, cyano, alkenyl, alkynyl, phosphine oxide, and phosphine sulfide groups.

  From the viewpoint of the dispersion stability of the light scattering particles, the viewpoint that the side effect that the luminescent nanocrystal particles settle is less likely to occur, the viewpoint of the ease of synthesizing the polymer dispersant, and the viewpoint of the stability of the functional group, acid functional As the group, a carboxyl group, a sulfo group, a phosphonic acid group and a phosphoric acid group are preferably used, and as the basic functional group, an amino group is preferably used. Among these, a carboxyl group, a phosphonic acid group and an amino group are more preferably used, and an amino group is most preferably used.

  A polymer dispersant having an acidic functional group has an acid value. The acid value of the polymer dispersant having an acidic functional group is preferably from 1 to 150 mgKOH / g. When the acid value is 1 mgKOH / g or more, sufficient dispersibility of the light-scattering particles is easily obtained, and when the acid value is 150 mgKOH / g or less, the storage stability of the pixel portion (cured product of the ink composition) is obtained. Is not easily reduced. The acid value of the polymer dispersant is preferably 50 mgKOH / g or less, more preferably 45 mgKOH / g or less, still more preferably 35 mgKOH / g or less, particularly preferably 30 mgKOH / g or less, particularly preferably 24 mgKOH / g or less.

The acid value of the polymer dispersant was determined by preparing a sample solution in which pg of the polymer dispersant was dissolved in 50 mL of a mixed solution obtained by mixing toluene and ethanol at a volume ratio of 1: 1 and 1 mL of a phenolphthalein test solution. Titrate with a 1 mol / L ethanol-made potassium hydroxide solution (a solution prepared by dissolving 7.0 g of potassium hydroxide in 5.0 mL of distilled water and adjusting the volume to 1000 mL by adding 95 vol% ethanol) until the sample liquid turns pink. I do. Then, the acid value can be calculated by the following equation.
Acid value = q × r × 5.611 / p
In the formula, q indicates the titer (mL) of the 0.1 mol / L ethanol potassium hydroxide solution required for titration, and r indicates the titer of the 0.1 mol / L ethanol potassium hydroxide solution required for titration. And p represents the mass (g) of the polymer dispersant.

  The polymer dispersant having a basic functional group has an amine value. The amine value of the polymer dispersant having a basic functional group is preferably from 1 to 200 mgKOH / g. When the amine value is 1 mgKOH / g or more, sufficient dispersibility of the light-scattering particles is easily obtained, and when the amine value is 200 mgKOH / g or less, the storage stability of the pixel portion (cured product of the ink composition) is improved. Is not easily reduced. The amine value of the polymer dispersant is preferably 5 mgKOH / g or more, more preferably 10 mgKOH / g or more. The amine value of the polymer dispersant is preferably 90 mgKOH / g or less, more preferably 50 mgKOH / g or less.

The amine value of the polymer dispersant was determined by preparing a sample solution prepared by dissolving xg of the polymer dispersant in 50 ml of a mixed solution of toluene and ethanol at a volume ratio of 1: 1 and 1 ml of bromophenol blue test solution. The titration is performed with 5 mol / L hydrochloric acid until the sample liquid turns green. Then, the amine value can be calculated by the following equation.
Amine value = y / x × 28.05
In the formula, y indicates the titer (ml) of 0.5 mol / L hydrochloric acid required for the titration, and x indicates the mass (g) of the polymer dispersant.

  The polymer dispersant may be a polymer of a single monomer (homopolymer) or a copolymer of a plurality of types of monomers (copolymer). Further, the polymer dispersant may be any of a random copolymer, a block copolymer or a graft copolymer. When the polymer dispersant is a graft copolymer, it may be a comb-shaped graft copolymer or a star-shaped graft copolymer. The polymer dispersant is, for example, an acrylic resin, a polyester resin, a polyurethane resin, a polyamide resin, a polyether, a phenol resin, a silicone resin, a polyurea resin, an amino resin, an epoxy resin, a polyamine such as polyethyleneimine and polyallylamine, and a polyimide. May be.

  Commercially available products can be used as the polymer dispersant. Examples of the commercially available products are Ajispar PB series manufactured by Ajinomoto Fine-Techno Co., Ltd., DISPERBYK series and BYK-series manufactured by BYK, and Efka series manufactured by BASF. Etc. can be used.

  Examples of commercially available products include "DISPERBYK-130", "DISPERBYK-161", "DISPERBYK-162", "DISPERBYK-163", "DISPERBYK-164", "DISPERBYK-166", and "DISPERBYK-166" manufactured by BYK Chemie. 167 "," DISPERBYK-168 "," DISPERBYK-170 "," DISPERBYK-171 "," DISPERBYK-174 "," DISPERBYK-180 "," DISPERBYK-182 "," DISPERBYK-183 "," DISPERBYK-184 " , “DISPERBYK-185”, “DISPERBYK-2000”, “DISPERBYK-2001”, “DISPERBYK-2008”, “DISP "RBYK-2009", "DISPERBYK-2020", "DISPERBYK-2022", "DISPERBYK-2025", "DISPERBYK-2050", "DISPERBYK-2070", "DISPERBYK-2096", "DISPERBYK-2150", "-DISPERY" 2155 "," DISPERBYK-2163 "," DISPERBYK-2164 "," BYK-LPN21116 ", and" BYK-LPN6919 ";" EFKA4010 "," EFKA4015 "," EFKA4046 "," EFKA4047 "," EFKA406 "manufactured by BASF. , “EFKA4080”, “EFKA4300”, “EFKA4310”, “EFKA4320”, “EFKA4330”, “EFK 4340 "," EFKA4560 "," EFKA4585 "," EFKA5207 "," EFKA1501 "," EFKA1502 "," EFKA1503 "and" EFKA PX-4701 ";" SOLSPERS 3000 "," SOLSPERS 9000 "," SOLSPERS9000 "," "SOLSPERS13240", "SOLSPERS13650", "SOLSPERS13940", "SOLSPERS11200", "SOLSPERS13940", "SOLSPERS16000", "SOLSPERS17000", "SOLSPERS18000", "SOLSPERS20000", "SOLSPERS21000", "SOLSPERS21000", Solsperse 24000, Solsperse 26000, Solsperse 27000, Solsperse 28000, Solsperse 32000 "SOLSPARSE 32500", "SOLSPERS32550", "SOLSPERS32600", "SOLSPERS33000", "SOLSPERS34750", "SOLSPERS35100", "SOLSPERS35200", "SOLSPERS36000", "SOLSPERS37500", "SOLSPERS38500", “SOLSPERS 39000”, “SOLSPERS 41000”, “SOLSPERS 54000”, “SOLSPERS 71000” and “SOLSPERS 76500”; “AJISPER PB821”, “AZIPERSPER PB822”, “AZIPERSPER PB881”, “PN411” manufactured by Ajinomoto Fine Techno Co., Ltd. And “PA111”; “TEGO Dispers 650”, “TEGO Dispers 660C”, “TEGO” manufactured by Evonik "Dispars 662C", "TEGO Dispers 670", "TEGO Dispers 685", "TEGO Dispers 700", "TEGO Dispers 710" and "TEGO Dispers 760W"; 725 "can be used.

  Examples of the polymer dispersant include, besides the commercially available products described above, a cationic monomer having a basic group and / or an anionic monomer having an acidic group, a monomer having a hydrophobic group, and if necessary, other monomers. (A nonionic monomer, a monomer having a hydrophilic group, etc.) can be used. As for the details of the cationic monomer, the anionic monomer, the monomer having a hydrophobic group, and other monomers, the monomers described in paragraphs 0034 to 0036 of JP-A-2004-250502 can be exemplified.

  Further, for example, compounds obtained by reacting a polyalkyleneimine with a polyester compound described in JP-A-54-37082 and JP-A-61-174939, and polyallylamine described in JP-A-9-169821. Compounds in which the amino group of the side chain is modified with a polyester, graft polymer having a polyester-type macromonomer as a copolymer component described in JP-A-9-171253, addition of polyester polyol described in JP-A-60-166318 Polyurethane and the like are preferred.

  The weight-average molecular weight of the polymer dispersant may be 1000 or more, from the viewpoint that the light-scattering particles can be dispersed well and the effect of improving external quantum efficiency can be further improved. Or 3000 or more. The weight average molecular weight of the polymer dispersant can disperse the light-scattering particles satisfactorily, further improve the effect of improving the external quantum efficiency, and discharge the viscosity of the inkjet ink for stable discharge. From the viewpoint of obtaining a suitable viscosity, the viscosity may be 100,000 or less, 50,000 or less, or 30,000 or less.

  From the viewpoint of the dispersibility of the light-scattering particles, the content of the polymer dispersant may be 0.5 parts by mass or more with respect to 100 parts by mass of the light-scattering particles, and may be 2 parts by mass or more. It may be 5 parts by mass or more. The content of the polymer dispersion may be 50 parts by mass or less, and 30 parts by mass or less based on 100 parts by mass of the light-scattering particles, from the viewpoint of wet heat stability of the pixel portion (cured product of the ink composition). Or 10 parts by mass or less.

[solvent]
Examples of the solvent include ethylene glycol monobutyl ether acetate, diethylene glycol monobutyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol dibutyl ether, diethyl adipate, dibutyl oxalate, dimethyl malonate, diethyl malonate, dimethyl succinate, and diethyl succinate. , 1,4-butanediol diacetate, glyceryl triacetate and the like.

  The boiling point of the solvent is preferably 150 ° C. or higher, more preferably 180 ° C. or higher, from the viewpoint of the continuous ejection stability of the inkjet ink. Further, when forming the pixel portion, it is necessary to remove the solvent from the ink composition before the ink composition is cured. Therefore, the boiling point of the solvent is preferably 300 ° C. or less from the viewpoint of easy removal of the solvent.

  The solvent preferably contains an acetate compound having a boiling point of 150 ° C. or higher. In this case, the affinity between the luminescent nanocrystal particles and the solvent is improved, and the luminescent nanocrystal particles can exhibit excellent luminescent characteristics. Specific examples of the acetate compound having a boiling point of 150 ° C. or higher include monoacetate compounds such as diethylene glycol monoethyl ether acetate, ethylene glycol monobutyl ether acetate, diethylene glycol monobutyl ether acetate, and dipropylene glycol methyl ether acetate; and 1,4-butanediol diacetate. Examples thereof include diacetate compounds such as acetate and propylene glycol diacetate, and triacetate compounds such as glyceryl triacetate.

  Since the photopolymerizable compound is used in the ink composition of the present embodiment, the light-scattering particles and the luminescent nanocrystal particles can be dispersed in the photopolymerizable compound without using a solvent. Therefore, according to the ink composition of the present embodiment, the step of removing the solvent by drying when forming the pixel portion becomes unnecessary.

[Antioxidant]
When the ink composition contains an antioxidant, a decrease in external quantum efficiency is likely to be suppressed, and a more excellent external quantum efficiency maintenance performance tends to be obtained. The antioxidant is not particularly limited, and for example, conventionally known antioxidants such as a phenolic antioxidant, an amine antioxidant, a phosphorus antioxidant, and a sulfur antioxidant can be used. Among these, a phosphorus-based antioxidant is preferable, and a phosphite triester compound is more preferably used.

The phosphite triester compound may be a compound represented by the formula: P (OR ³ ) ₃ . In the formula, a plurality of R ³ each independently represent a monovalent organic group. Two R ³ of the plurality of R ³ may also be bonded to each other to form a ring.

  The monovalent organic group sufficiently satisfies the required performance of compatibility with other components (photopolymerizable compound and the like) in the ink-jet ink, which is required for the ink-jet ink, and can further suppress the decrease in the external quantum efficiency of the ink-jet ink. From the viewpoint, it is preferably a monovalent hydrocarbon group. Examples of the monovalent hydrocarbon group include an alkyl group, an aryl group, and an alkenyl group. The monovalent hydrocarbon group may have 1 to 30 carbon atoms, and may have 4 to 18 carbon atoms from the viewpoint of solubility.

  The alkyl group may be linear or branched. Examples of the alkyl group include a 2-ethylhexyl group, a butyl group, an octyl group, a nonyl group, a decyl group, an isodecyl group, a dodecyl group, a hexadecyl group, and an octadecyl group.

  Examples of the aryl group include a phenyl group, a naphthyl group, a tert-butylphenyl group, a di-tert-butylphenyl group, an octylphenyl group, a nonylphenyl group, an isodecylphenyl group, an isodecylphenyl group, and an isodecylnaphthyl group. No.

  The monovalent hydrocarbon group is preferably an alkyl group or an aryl group, and more preferably an alkyl group or a phenyl group, from the viewpoint of further suppressing a decrease in external quantum efficiency.

Preferably, at least two of the plurality of R ³ are the same as each other. Preferably, at least one of the plurality of R ³ is a phenyl group, and more preferably, at least two of the plurality of R ³ are a phenyl group. Of the plurality of R ³ , at least one is preferably a phenyl group, and one is an alkyl group (preferably a branched alkyl group). That is, the phosphite triester compound preferably has at least one phenyl group and one alkyl group. When the phosphite triester compound has the above-mentioned functional group, it sufficiently satisfies the performance required for the ink-jet ink, such as compatibility with other components (a photopolymerizable compound, etc.) in the ink-jet ink, and the fluorescent property of the ink-jet ink. The decrease in quantum yield is further suppressed.

  Specific examples of the compound represented by the formula (2) include triphenyl phosphite (triphenyl phosphite), 2-ethylhexyl diphenyl phosphite, diphenyl octyl phosphite, and the like.

  The content of the phosphite triester compound may be 0.01% by mass or more, based on the mass of the non-volatile content of the ink composition, from the viewpoint that the decrease in external quantum efficiency is further suppressed. It may be 1% by mass or more, 1% by mass or more, or 5% by mass or more. Since the decrease in external quantum efficiency can be more effectively suppressed even by adding a small amount, the content of the phosphite triester compound is preferably 10% by mass or less based on the mass of the nonvolatile components of the ink composition. The content is more preferably 7% by mass or less, further preferably 5% by mass or less, and still more preferably 3% by mass or less. When the content of the phosphite triester compound is within the above range, at the time of forming the coating film, in addition to being able to ensure better film strength, bleeding to the surface of the phosphite triester compound is more likely. Suppressed and excellent external quantum efficiency and its maintenance performance can be ensured.

  The content of the phosphite triester compound may be 0.01 part by mass or more with respect to 100 parts by mass of the photopolymerizable compound, from the viewpoint that a decrease in external quantum efficiency is further suppressed. The amount may be at least 0.5 part by mass, at least 1 part by mass, or at least 3 parts by mass. Since the lowering of the external quantum efficiency can be more effectively suppressed even by adding a small amount, the content of the phosphite triester compound may be 10 parts by mass or less based on 100 parts by mass of the photopolymerizable compound. , 7 parts by mass or less, or 5 parts by mass or less. When the content of the phosphite triester compound is within the above range, in addition to being able to ensure better film strength at the time of forming the coating film, the bleeding to the surface of the phosphite triester compound is further improved. It tends to be able to suppress and secure excellent external quantum efficiency and its maintenance performance.

  The phosphite triester-based compound may be liquid or solid at room temperature (25 ° C.), but is preferably compatible with other components (such as a photopolymerizable compound) in the inkjet ink. It is a liquid at room temperature (25 ° C.) from the viewpoint of sufficiently satisfying the required performance specific to the inkjet ink and further suppressing a decrease in external quantum efficiency. The melting point of the phosphite triester compound may be 20 ° C. or lower, or 10 ° C. or lower.

[Thiol compound]
When the ink composition contains a thiol compound, a decrease in external quantum efficiency is likely to be suppressed, and more excellent external quantum efficiency maintenance performance tends to be obtained. The thiol compound is not particularly limited, but a compound having two or three primary mercapto groups in one molecule is preferably used. A primary mercapto group means a mercapto group bonded to a primary carbon atom. That is, the thiol compound has —CH ₂ —SH as a partial structure. The number of primary mercapto groups in the thiol compound is preferably two or three, and more preferably two, from the viewpoint of easily suppressing the increase in viscosity of the ink composition over time.

  When the thiol compound has a primary mercapto group, when the ink composition is cured by irradiation with an active energy ray (for example, ultraviolet light), for example, a secondary or tertiary mercapto group (secondary or secondary) is used. As compared with a thiol compound having a tertiary carbon atom (mercapto group), the composition can be cured with a smaller exposure dose (irradiation dose), and a decrease in external quantum efficiency is more easily suppressed.

The thiol compound may further have a substituted or unsubstituted aliphatic hydrocarbon group in addition to the primary mercapto group, and may further have a carbonyloxy group (—COO—). The thiol compound is preferably a part represented by the following formula (2) from the viewpoint of further improving the ejection stability, reducing the leakage light, and further suppressing the decrease in external quantum efficiency. Having a structure.

In the formula (2), n represents an integer of 0 or more, X represents a methylene group (—CH ₂ —) or a carbonyl group (—CO—), and * represents a bond. X is preferably a carbonyl group. n may be, for example, 1 to 10, or 1 to 5. When X is a carbonyl group, n is preferably 1 or 2, and more preferably 2.

The thiol compound is preferably a compound represented by the following formula (3), from the viewpoint of further improving ejection stability, reducing leakage light, and further suppressing the decrease in external quantum efficiency. is there.

In Formula (3), R ⁴ represents an m-valent hydrocarbon group, m represents 2 or 3, and n and X have the same meanings as n in Formula (2). R ⁴ is preferably an m-valent substituted or unsubstituted aliphatic hydrocarbon group. The carbon number of R ⁴ may be 1 or more, or 4 or more, and may be 20 or less, or 10 or less. The substituted aliphatic hydrocarbon group may be one in which some hydrogen atoms of the aliphatic hydrocarbon group are substituted with a hydroxyl group, and some carbon atoms of the aliphatic hydrocarbon group are substituted with an oxygen atom. Group. The substituted aliphatic hydrocarbon group may include, for example, a (poly) oxyalkylene group. Here, the “(poly) oxyalkylene group” means at least one of an oxyalkylene group and a polyoxyalkylene group in which two or more alkylene groups are connected by an ether bond. The (poly) oxyalkylene group may be, for example, a (poly) oxyethylene group.

  The viscosity of the thiol compound at 25 ° C. may be, for example, 20 mPa · s or more, or 100 mPa · s or more, 200 mPa · s or less, or 170 Pa · s or less, from the viewpoint of ejection stability during inkjet printing. You may. In the present specification, the viscosity of the thiol compound is, for example, a viscosity measured by an E-type viscometer.

  Examples of the thiol compound having three primary mercapto groups include trimethylolpropane tris (3-mercaptopropionate). Examples of the thiol compound having two primary mercapto groups include tetraethylene glycol bis (3-mercaptopropionate). The thiol compound may be used alone or in combination of two or more.

  Commercial products can also be used for the thiol compound. Examples of commercially available thiol compounds having three primary mercapto groups include “TMMP” (trade name) and “PEPT” (trade name) manufactured by SC Organic Chemical Co., Ltd. As a commercially available thiol compound having two primary mercapto groups, "EGMP-4" (trade name) manufactured by SC Organic Chemical Co., Ltd. can be mentioned.

  The content of the thiol compound is not less than 1.0 part by mass with respect to 100 parts by mass of the ethylenically unsaturated monomer from the viewpoint of increasing the viscosity of the ink composition over time and suppressing the decrease in external quantum efficiency. The amount may be 8.0 parts by mass or more, or 14.0 parts by mass or more. The content of the thiol compound may be 32.5 parts by mass or less and 23.0 parts by mass or less with respect to 100 parts by mass of the ethylenically unsaturated monomer from the viewpoint of increasing the viscosity of the ink composition over time. And 15.0 parts by mass or less.

  The viscosity of the ink composition described above at 40 ° C. may be, for example, 2 mPa · s or more, 5 mPa · s or more, or 7 mPa · s or more from the viewpoint of ejection stability during inkjet printing. You may. The viscosity at 40 ° C. of the ink composition may be 20 mPa · s or less, 15 mPa · s or less, or 12 mPa · s or less. The viscosity at 40 ° C. of the ink composition is, for example, 2 to 20 mPa · s, 2 to 15 mPa · s, 2 to 12 mPa · s, 5 to 20 mPa · s, 5 to 15 mPa · s, 5 to 12 mPa · s, 7 to It may be 20 mPa · s, 7 to 15 mPa · s, or 7 to 12 mPa · s. In the present specification, the viscosity of the ink composition is, for example, a viscosity measured by an E-type viscometer.

  The viscosity of the ink composition at 23 ° C. may be, for example, 5 mPa · s or more, 10 mPa · s or more, or 15 mPa · s or more, from the viewpoint of ejection stability during inkjet printing. Good. The viscosity of the ink composition at 23 ° C. may be 40 mPa · s or less, 35 mPa · s or less, 30 mPa · s or less, or 25 mPa · s or less. The viscosity of the ink composition at 23 ° C. may be, for example, 5 to 40 mPa · s, 10 to 35 mPa · s, 10 to 30 mPa · s, 15 to 30 mPa · s, or 15 to 25 mPa · s.

  When the viscosity at 40 ° C. of the ink composition is 2 mPa · s or more, or the viscosity at 23 ° C. of the ink composition is 5 mPa · s or more, the meniscus shape of the inkjet ink at the tip of the ink ejection hole of the ejection head , The ejection control of the inkjet ink (for example, the control of the ejection amount and the ejection timing) becomes easy. On the other hand, when the viscosity at 40 ° C. of the ink composition is 20 mPa · s or less, or when the viscosity at 40 ° C. of the ink composition is 40 mPa · s or less, the inkjet ink is smoothly discharged from the ink discharge holes. Can be.

  The surface tension of the ink composition is preferably a surface tension suitable for an ink jet system, specifically, preferably in the range of 20 to 40 mN / m, and more preferably 25 to 35 mN / m. . By setting the surface tension within the range, it is possible to suppress the occurrence of flight bending. Note that the flight bend means that when the ink composition is ejected from the ink ejection holes, the landing position of the ink composition is shifted by 30 μm or more from the target position. When the surface tension is 40 mN / m or less, the meniscus shape at the tip of the ink ejection hole is stabilized, so that ejection control of the ink composition (for example, control of ejection amount and ejection timing) becomes easy. On the other hand, when the surface tension is 20 mN / m or more, the occurrence of flight bending can be suppressed. That is, a pixel portion that is not accurately landed in the pixel portion formation region to be landed and is insufficiently filled with the ink composition occurs, or a pixel portion formation region (or a pixel portion) adjacent to the pixel portion formation region to be landed The ink composition does not land on the surface and color reproducibility is not reduced.

  When the ink composition of the present embodiment is used as an ink composition for an ink jet system, it is preferable to apply the ink composition to a piezo jet type ink jet recording apparatus using a mechanical ejection mechanism using a piezoelectric element. In the piezo jet method, the ink composition is not instantaneously exposed to a high temperature during ejection. Therefore, the luminescent nanocrystal particles are less likely to be altered, and the luminescent characteristics as expected are more easily obtained in the pixel portion (light conversion layer).

  As described above, one embodiment of the ink composition for a color filter has been described. However, the ink composition of the above-described embodiment can be used, for example, by a photolithography method in addition to the ink jet method. In this case, the ink composition contains an alkali-soluble resin as a binder polymer.

  When the ink composition is used in a photographic method, first, the ink composition is applied on a substrate, and when the ink composition contains a solvent, the ink composition is further dried to form a coating film. The coating film thus obtained is soluble in an alkali developing solution, and is patterned by being treated with the alkali developing solution. At this time, the alkali developer is mostly an aqueous solution from the viewpoint of, for example, easiness of treating the developer as a waste liquid, and thus the coating film of the ink composition is treated with the aqueous solution. On the other hand, in the case of an ink composition using luminescent nanocrystal particles (such as quantum dots), the luminescent nanocrystal particles are unstable with respect to water, and the luminescence (eg, fluorescence) is impaired by moisture. For this reason, in the present embodiment, an ink jet system which does not require treatment with an alkali developing solution (aqueous solution) is preferable.

  Further, even when the coating film of the ink composition is not subjected to the treatment with the alkali developing solution, when the ink composition is alkali-soluble, the coating film of the ink composition easily absorbs atmospheric moisture, As time elapses, the light-emitting properties (eg, fluorescence) of the light-emitting nanocrystal particles (such as quantum dots) deteriorate. From this viewpoint, in the present embodiment, the coating film of the ink composition is preferably alkali-insoluble. That is, the ink composition of the present embodiment is preferably an ink composition capable of forming an alkali-insoluble coating film. Such an ink composition can be obtained by using an alkali-insoluble photopolymerizable compound as the photopolymerizable compound. When the coating film of the ink composition is alkali-insoluble, the amount of the coating film of the ink composition dissolved at 25 ° C. in a 1% by mass aqueous solution of potassium hydroxide is based on the total weight of the coating film of the ink composition. It means 30% by mass or less. The dissolution amount of the coating film of the ink composition is preferably 10% by mass or less, more preferably 3% by mass or less. Note that the ink composition is an ink composition capable of forming an alkali-insoluble coating film, which is obtained by applying the ink composition on a base material, and then drying at 80 ° C. for 3 minutes when a solvent is contained. It can be confirmed by measuring the above-mentioned dissolved amount of the obtained coating film having a thickness of 1 μm.

<Method for producing ink composition>
The ink composition of the embodiment described above is obtained, for example, by mixing the components of the ink composition described above and performing a dispersion treatment. Hereinafter, as an example, a method for producing an ink composition containing light scattering particles and a polymer dispersant will be described.

  The method for producing an ink composition includes, for example, a first step of preparing a dispersion of light-scattering particles containing light-scattering particles and a polymer dispersant, and a dispersion of light-scattering particles and a luminescent nanoparticle. A second step of mixing the crystal particles. In this method, the dispersion of the light-scattering particles may further contain a photopolymerizable compound, and in the second step, the photopolymerizable compound may be further mixed. According to this method, the light scattering particles can be sufficiently dispersed. Therefore, it is possible to improve the optical characteristics (for example, external quantum efficiency) of the pixel portion and easily obtain a luminescent ink composition having excellent ejection stability.

  In the step of preparing the dispersion of the light-scattering particles, the light-scattering particles, the polymer dispersant, and, in some cases, a photopolymerizable compound are mixed, and the dispersion of the light-scattering particles is performed by performing a dispersion treatment. May be prepared. The mixing and dispersing treatment may be performed using a dispersing device such as a bead mill, a paint conditioner, a planetary stirrer, and a jet mill. It is preferable to use a bead mill or a paint conditioner from the viewpoint that the dispersibility of the light-scattering particles becomes good and the average particle diameter of the light-scattering particles is easily adjusted to a desired range. By mixing the light-scattering particles and the polymer dispersant before mixing the light-emitting nanocrystal particles and the light-scattering particles, the light-scattering particles can be more sufficiently dispersed. Therefore, excellent ejection stability and excellent external quantum efficiency can be more easily obtained.

  The method for producing an ink composition may further include, before the second step, a step of preparing a dispersion of the luminescent nanocrystal particles, which contains the luminescent nanocrystal particles and a photopolymerizable compound. Good. In this case, in the second step, a dispersion of the light scattering particles and a dispersion of the luminescent nanocrystal particles are mixed. In the step of preparing the dispersion of the luminescent nanocrystal particles, the luminescent nanocrystal particles may be mixed with a photopolymerizable compound and subjected to a dispersion treatment to prepare the luminescent nanocrystal particle dispersion. As the luminescent nanocrystal particles, luminescent nanocrystal particles having an organic ligand on the surface thereof may be used. That is, the luminescent nanocrystal particle dispersion may further include an organic ligand. The mixing and dispersing treatment may be performed using a dispersing device such as a bead mill, a paint conditioner, a planetary stirrer, and a jet mill. It is preferable to use a bead mill, a paint conditioner, or a jet mill from the viewpoint that the dispersibility of the luminescent nanocrystal particles becomes good and the average particle size of the luminescent nanocrystal particles can be easily adjusted to a desired range. According to this method, the luminescent nanocrystal particles can be sufficiently dispersed. Therefore, it is possible to improve the optical characteristics (for example, external quantum efficiency) of the pixel portion and easily obtain an ink composition having excellent ejection stability.

  In this manufacturing method, other components (for example, a solvent, an antioxidant, a thiol compound, and the like) other than the above-described components may be further used. In this case, other components may be contained in the luminescent nanocrystal particle dispersion or may be contained in the light scattering particle dispersion. Further, other components may be mixed with the composition obtained by mixing the luminescent nanocrystal particle dispersion and the light scattering particle dispersion.

<Cured product of ink composition>
A cured product of the ink composition of one embodiment (hereinafter also referred to as “cured ink product”) includes luminescent nanocrystalline particles and a curing component, and the curing component includes a polymer including a structural unit having an ether ring. Contains coalescence. This ink cured product can be obtained, for example, by curing the ink composition of the above-described embodiment. Therefore, the cured ink may contain each component (excluding volatile components) contained in the ink composition of the embodiment described above, and may further contain, for example, light scattering particles. When the ink composition is cured, a cured product of an organic component in the ink composition becomes a cured component.

  The luminescent nanocrystal particles contained in the cured ink may be the luminescent nanocrystal particles contained in the above-described ink composition. The content of the luminescent nanocrystal particles in the cured ink is preferably based on the total mass of the cured product of the luminescent ink composition, from the viewpoint of improving the external quantum efficiency and obtaining excellent emission intensity. Is more than 20% by mass, more preferably at least 23% by mass, even more preferably at least 25% by mass. The content of the luminescent nanocrystal particles is preferably 50% by mass or less based on the total mass of the cured ink from the viewpoint of excellent reliability of the pixel portion and excellent luminescence intensity. From the same viewpoint, the content of the luminescent nanocrystal particles may be 40% by mass or less, 35% by mass or less, or 30% by mass or less based on the total mass of the cured ink. There may be.

  The polymer (polymer containing a structural unit having an ether ring) contained in the cured ink is a polymer obtained by polymerization of the first photopolymerizable compound (for example, the first photopolymerizable compound). (Radical polymer).

  The structural unit having an ether ring is, for example, a structural unit constituting a main chain skeleton of a polymer, and is linked to another structural unit (for example, a structural unit having an ether ring) via a carbon-carbon bond constituting an ether ring. Join. The ether ring in the structural unit having an ether ring may be a 4-, 5-, or 6-membered ring, and is preferably a 5-membered ring. The structural unit having an ether ring is preferably a structural unit having a tetrahydrofuran ring.

［式（ＩＶ）中、＊は結合手を示す。Ｘ^１は式（Ｉ）におけるＸと同義であり、Ｙ^１は式（Ｉ）におけるＹと同義である。重合体における複数のＸ^１は互いに同一であっても異なっていてもよく、複数のＹ^１は互いに同一であっても異なっていてもよい。］ The structural unit having an ether ring is, for example, a structural unit represented by the following formula (IV).

[In formula (IV), * represents a bond. X ¹ has the same meaning as X in formula (I), and Y ¹ has the same meaning as Y in formula (I). A plurality of X ¹ in the polymer may be the same or different from each other, and a plurality of Y ¹ may be the same or different from each other. ]

［式（ＩＶａ）中、＊は結合手を示す。Ｒ^１ａは式（ＩＩＩ）におけるＲ^１と同義である。重合体における複数のＲ^１ａは互いに同一であっても異なっていてもよい。］ X ¹ is preferably a group represented by the above formula (III), and Y ¹ is preferably a methylene group. That is, the structural unit having an ether ring is preferably a structural unit represented by the following formula (IVa).

[In formula (IVa), * represents a bond. R ^1a has the same meaning as ^{R 1} in formula (III). A plurality of R ^1a in the polymer may be the same or different from each other. ]

R ^1a is preferably an alkyl group, more preferably a methyl group.

［式（Ｖ）中、＊は結合手を示す。Ｘ^２は式（Ｉ）におけるＸと同義であり、Ｙ^２は式（Ｉ）におけるＹと同義である。重合体における複数のＸ^２は互いに同一であっても異なっていてもよく、複数のＹ^２は互いに同一であっても異なっていてもよい。Ｘ^２はＸ^１と同一であっても異なっていてもよい。Ｙ^２はＹ^１と同一であっても異なっていてもよい。］ The polymer containing a structural unit having an ether ring may be composed of only the structural unit represented by the formula (IV), or may be composed of only the structural unit represented by the formula (IVa). The polymer containing a structural unit having an ether ring may further include a structural unit represented by the following formula (V) in addition to the structural unit represented by the formula (IV).

[In formula (V), * represents a bond. X ² has the same meaning as X in the formula (I), and Y ² has the same meaning as Y in the formula (I). A plurality of X ² in the polymer may be the same or different, and a plurality of Y ² may be the same or different. X ² may be the same or different from X ¹ . Y ² may be the same or different from Y ¹ . ]

［式（Ｖａ）中、＊は結合手を示す。Ｒ^１ｂは式（ＩＩＩ）におけるＲ^１と同義である。重合体における複数のＲ^１ｂは互いに同一であっても異なっていてもよい。Ｒ^１ａとＲ^１ｂとは同一であっても異なっていてもよい。］ X ² is preferably a group represented by the above formula (III), and Y ² is preferably a methylene group. That is, the structural unit represented by the formula (V) is preferably a structural unit represented by the following formula (Va).

[In formula (Va), * represents a bond. R ^1b has the same ^{meaning as} R ¹ in formula (III). A plurality of R ^1b in the polymer may be the same or different from each other. R ^1a and R ^1b may be the same or different. ]

R ^1b is preferably an alkyl group, and more preferably a methyl group.

  The polymer containing a structural unit having an ether ring may be composed of only the structural unit represented by the formula (IV) and the structural unit represented by the following formula (V). Further, it may be included. The polymer containing a structural unit having an ether ring may be composed of only the structural unit represented by the formula (IVa) and the structural unit represented by the following formula (Va).

  In a polymer containing a structural unit having an ether ring, when the total of the structural unit represented by the formula (IV) and the structural unit represented by the formula (V) is set to 100, the polymer is represented by the formula (IV) The ratio of the structural units may be 95 or more, 80 or more, or 50 or more. The ratio of the structural unit represented by the formula (IV) in the polymer is preferably 100. That is, the polymer preferably does not contain the structural unit represented by the formula (V).

  When the total of the structural unit represented by the formula (IVa) and the structural unit represented by the formula (Va) is 100, the proportion of the structural unit represented by the formula (IVa) is 95 or more, 80 or more, or It may be 50 or more. The ratio of the structural unit represented by the formula (IVa) in the polymer is preferably 100.

  The content of the light-scattering particles in the cured ink may be 0.1% by mass or more and 1% by mass or more based on the total mass of the cured ink, from the viewpoint of improving the external quantum efficiency. The amount may be 5% by mass or more, 7% by mass or more, 10% by mass or more, or 12% by mass or more. The content of the light-scattering particles may be 60% by mass or less, based on the total mass of the ink cured product, from the viewpoint of improving the external quantum efficiency and improving the reliability of the pixel portion. % Or less, 40% by weight or less, 30% by weight or less, 25% by weight or less, 20% by weight or less, 15% by weight %.

<Ink composition set>
An ink composition set according to one embodiment includes the ink composition according to the above-described embodiment. The ink composition set includes, in addition to the ink composition (luminescent ink composition) of the above-described embodiment, an ink composition containing no luminescent nanocrystal particles (non-luminescent ink composition). Good. The non-light-emitting ink composition may be a conventionally known photopolymerizable ink composition, and the ink composition of the above-described embodiment (the light-emitting ink composition) except that it does not contain the light-emitting nanocrystal particles. )).

  Since the non-light-emitting ink composition does not contain luminescent nanocrystal particles, light is applied to a pixel portion formed by the non-light-emitting ink composition (a pixel portion including a cured product of the non-light-emitting ink composition). When the light is incident, the light emitted from the pixel unit has substantially the same wavelength as the incident light. Therefore, the non-light emitting ink composition is suitably used for forming a pixel portion of the same color as light from a light source. For example, when the light from the light source is light having a wavelength in the range of 420 to 480 nm (blue light), the pixel portion formed by the non-light-emitting ink composition may be a blue pixel portion.

  The non-light emitting ink composition preferably contains light scattering particles. When the non-light-emitting ink composition contains light-scattering particles, according to the pixel portion formed by the non-light-emitting ink composition, light incident on the pixel portion can be scattered. In addition, it is possible to reduce a difference in light intensity at a viewing angle of light emitted from the pixel portion.

<Light conversion layer and color filter>
Hereinafter, the details of the light conversion layer and the color filter obtained using the ink composition set of the above embodiment will be described with reference to the drawings. In the following description, the same or corresponding elements will be denoted by the same reference characters, without redundant description.

  FIG. 1 is a schematic sectional view of a color filter according to one embodiment. As shown in FIG. 1, the color filter 100 includes a base 40 and a light conversion layer 30 provided on the base 40. The light conversion layer 30 includes a plurality of pixel units 10 and a light shielding unit 20.

  The light conversion layer 30 includes, as the pixel unit 10, a first pixel unit 10a, a second pixel unit 10b, and a third pixel unit 10c. The first pixel unit 10a, the second pixel unit 10b, and the third pixel unit 10c are arranged in a lattice so as to be repeated in this order. The light-shielding portion 20 is provided between adjacent pixel portions, that is, between the first pixel portion 10a and the second pixel portion 10b, between the second pixel portion 10b and the third pixel portion 10c, and between the adjacent pixel portions. Is provided between the pixel section 10c and the first pixel section 10a. In other words, these adjacent pixel units are separated from each other by the light shielding unit 20.

  The first pixel portion 10a and the second pixel portion 10b are light-emitting pixel portions (light-emitting pixel portions) each including the cured ink of the above-described embodiment (for example, the cured ink composition of the embodiment). is there. The cured product contains luminescent nanocrystal particles, a curing component, and light scattering particles. The curing component contains a polymer of a photopolymerizable compound. That is, the first pixel unit 10a includes the first curing component 13a, and the first light-emitting nanocrystal particles 11a and the first light-scattering particles 12a dispersed in the first curing component 13a, respectively. Including. Similarly, the second pixel portion 10b includes a second hardening component 13b, a second light-emitting nanocrystal particle 11b and a second light-scattering particle 12b dispersed in the second hardening component 13b, respectively. including. In the first pixel portion 10a and the second pixel portion 10b, the first hardening component 13a and the second hardening component 13b may be the same or different, and may be different from the first light scattering particles 12a. The second light scattering particles 12b may be the same or different.

  The first luminescent nanocrystalline particles 11a are red luminescent nanocrystalline particles that absorb light having a wavelength in the range of 420 to 480 nm and emit light having an emission peak wavelength in the range of 605 to 665 nm. That is, the first pixel unit 10a may be referred to as a red pixel unit for converting blue light into red light. The second luminescent nanocrystal particles 11b are green luminescent nanocrystal particles that absorb light having a wavelength in the range of 420 to 480 nm and emit light having an emission peak wavelength in the range of 500 to 560 nm. That is, the second pixel portion 10b may be referred to as a green pixel portion for converting blue light into green light.

  The content of the luminescent nanocrystal particles and the content of the light scattering particles in the luminescent pixel portion are the same as the ranges described above as the content of the luminescent nanocrystal particles and the content of the light scattering particles in the cured ink. May be. At this time, the “total mass of the cured ink” is rephrased as the “total mass of the pixel portion”.

  The third pixel portion 10c is a non-light-emitting pixel portion (non-light-emitting pixel portion) including a cured product of the above-described non-light-emitting ink composition. The cured product does not contain luminescent nanocrystalline particles, but contains light scattering particles and a curing component. The curing component includes, for example, a polymer of a photopolymerizable compound. That is, the third pixel portion 10c includes the third hardening component 13c and the third light-scattering particles 12c dispersed in the third hardening component 13c. The third light scattering particles 12c may be the same as or different from the first light scattering particles 12a and the second light scattering particles 12b.

  The third pixel portion 10c has, for example, a transmittance (scattered light transmittance) of 30% or more for light having a wavelength in the range of 420 to 480 nm. Therefore, the third pixel portion 10c functions as a blue pixel portion when using a light source that emits light having a wavelength in the range of 420 to 480 nm. Note that the transmittance of the third pixel portion 10c can be measured with a microspectroscope.

  The thickness of the pixel portion (the first pixel portion 10a, the second pixel portion 10b, and the third pixel portion 10c) is, for example, 1 μm or more, 2 μm or more, or 3 μm or more. You may. The thickness of the pixel portion (the first pixel portion 10a, the second pixel portion 10b, and the third pixel portion 10c) may be, for example, 30 μm or less, 20 μm or less, or 15 μm or less. You may.

  The light shielding portion 20 is a so-called black matrix provided for the purpose of separating adjacent pixel portions to prevent color mixture and preventing light from leaking from a light source. The material forming the light-shielding portion 20 is not particularly limited. In addition to metal such as chromium, curing of a resin composition containing light-shielding particles such as carbon fine particles, metal oxides, inorganic pigments, and organic pigments in a binder polymer is cured. Things can be used. As the binder polymer used here, one or a mixture of two or more resins such as polyimide resin, acrylic resin, epoxy resin, polyacrylamide, polyvinyl alcohol, gelatin, casein, cellulose, photosensitive resin, O / W Emulsion-type resin compositions (for example, those obtained by emulsifying reactive silicone) can be used. The thickness of the light shielding portion 20 may be, for example, 0.5 μm or more, and may be 10 μm or less.

  The base material 40 is a transparent base material having optical transparency, for example, a transparent glass substrate such as quartz glass, Pyrex (registered trademark) glass, a synthetic quartz plate, a transparent resin film, a resin film for optical use, or the like. A flexible substrate or the like can be used. Among these, it is preferable to use a glass substrate made of non-alkali glass containing no alkali component in the glass. Specifically, “7059 glass”, “1737 glass”, “Eagle 200” and “Eagle XG” manufactured by Corning, “AN100” manufactured by Asahi Glass, “OA-10G” and “OA-10G” manufactured by NEC Corporation OA-11 "is preferred. These are materials having a small coefficient of thermal expansion and are excellent in dimensional stability and workability in high-temperature heat treatment.

  The color filter 100 including the light conversion layer 30 described above is suitably used when a light source that emits light having a wavelength in the range of 420 to 480 nm is used.

  The color filter 100 is formed, for example, by forming the light-shielding portions 20 in a pattern on the base material 40, and then, in the pixel portion forming region partitioned by the light-shielding portions 20 on the base material 40, the ink composition ( (Ink jet ink) is selectively adhered by an ink jet method, and the ink composition is cured by irradiation with active energy rays or heating.

  The method of forming the light-shielding portion 20 is to form a metal thin film such as chromium or a thin film of a resin composition containing light-shielding particles in a region serving as a boundary between a plurality of pixel portions on one surface side of the base material 40. Then, a method of patterning the thin film and the like can be mentioned. The metal thin film can be formed by, for example, a sputtering method or a vacuum evaporation method, and the thin film of the resin composition containing light-shielding particles can be formed by, for example, a method such as coating or printing. As a method of performing patterning, a photolithography method or the like can be given.

  Examples of the ink jet method include a bubble jet (registered trademark) method using an electrothermal converter as an energy generating element, a piezo jet method using a piezoelectric element, and the like.

When the ink composition is cured by irradiation with active energy rays (for example, ultraviolet rays), for example, a mercury lamp, a metal halide lamp, a xenon lamp, an LED, or the like may be used. The wavelength of the light to be irradiated may be, for example, 200 nm or more and 440 nm or less. The exposure amount may be, for example, 10 mJ / cm ² or more and 4000 mJ / cm ² or less.

  The drying temperature for volatilizing the solvent may be, for example, 50 ° C. or higher and 150 ° C. or lower. The drying time may be, for example, not less than 3 minutes and not more than 30 minutes.

  As described above, one embodiment of the color filter and the light conversion layer, and the manufacturing method thereof are described, but the present invention is not limited to the above-described embodiment.

  For example, the light conversion layer may be replaced with the third pixel portion 10c, or in addition to the third pixel portion 10c, may include a pixel portion (a blue pixel) including a cured product of an ink composition containing blue light-emitting nanocrystal particles. Part). Further, the light conversion layer includes a pixel portion (for example, a yellow pixel portion) including a cured product of a luminescent ink composition containing nanocrystalline particles that emit light of a color other than red, green, and blue. Is also good. In these cases, it is preferable that each of the luminescent nanocrystal particles contained in each pixel portion of the light conversion layer has an absorption maximum wavelength in the same wavelength region.

  Further, at least a part of the pixel portion of the light conversion layer may include a cured product of a composition containing a pigment other than the luminescent nanocrystal particles.

  Further, the color filter may include an ink-repellent layer made of a material having an ink-repellent property, which is narrower than the light-shielding portion, on the pattern of the light-shielding portion. Also, instead of providing an ink-repellent layer, after forming a photocatalyst-containing layer as a wettability variable layer in a solid coating shape in a region including a pixel portion formation region, light is applied to the photocatalyst-containing layer via a photomask. The exposure may be performed by irradiation to selectively increase the ink affinity of the pixel portion formation region. Examples of the photocatalyst include titanium oxide and zinc oxide.

  Further, the color filter may include an ink receiving layer containing hydroxypropylcellulose, polyvinyl alcohol, gelatin or the like between the substrate and the pixel portion.

  Further, the color filter may include a protective layer on the pixel portion. This protective layer flattens the color filter and prevents components contained in the pixel portion, or components contained in the pixel portion and components contained in the photocatalyst containing layer from being eluted into the liquid crystal layer. It is provided. As a material constituting the protective layer, a material used as a known protective layer for a color filter can be used.

  Further, in the production of the color filter and the light conversion layer, the pixel portion may be formed by a photolithography method instead of the inkjet method. In this case, first, the ink composition is applied to the substrate in a layer form to form an ink composition layer. Next, the ink composition layer is exposed to light in a pattern and then developed using a developer. Thus, a pixel portion made of a cured product of the ink composition is formed. Since the developer is usually alkaline, an alkali-soluble material is used as a material for the ink composition. However, from the viewpoint of material use efficiency, the inkjet method is superior to the photolithography method. This is because, in the photolithography method, approximately 2/3 or more of the material is removed in principle, and the material is wasted. For this reason, in the present embodiment, it is preferable to form a pixel portion by an inkjet method using an inkjet ink.

  In addition, the pixel portion of the light conversion layer of the present embodiment may further contain a pigment having substantially the same color as the emission color of the luminescent nanocrystal particles, in addition to the above-described luminescent nanocrystal particles. For example, when a pixel portion containing luminescent nanocrystal particles that absorb and emit blue light is used as a pixel portion of a liquid crystal display element, quasi-white light having a peak at 450 nm or blue light as light from a light source is used. However, when the concentration of the luminescent nanocrystal particles in the pixel portion is not sufficient, the light from the light source passes through the light conversion layer when the liquid crystal display element is driven. The transmitted light (blue light, leaked light) from this light source mixes with the light emitted by the luminescent nanocrystal particles. From the viewpoint of preventing a decrease in color reproducibility due to the occurrence of such color mixing, a pigment may be contained in the pixel portion of the light conversion layer. In order to contain the pigment in the pixel portion, the pigment may be contained in the ink composition.

  In addition, one or two types of luminescent pixel portions of the red pixel portion (R), the green pixel portion (G), and the blue pixel portion (B) in the light conversion layer of the present embodiment The pixel portion may contain a coloring material without containing crystal particles. As the coloring material that can be used here, a known coloring material can be used. For example, as the coloring material used for the red pixel portion (R), a diketopyrrolopyrrole pigment and / or an anionic red organic dye are used. No. Examples of the coloring material used for the green pixel portion (G) include at least one selected from the group consisting of a copper halide phthalocyanine pigment, a phthalocyanine-based green dye, and a mixture of a phthalocyanine-based blue dye and an azo-based yellow organic dye. Examples of the coloring material used for the blue pixel portion (B) include an ε-type copper phthalocyanine pigment and / or a cationic blue organic dye. When used in the light conversion layer, the amount of use of these coloring materials is 1 to 5 mass based on the total mass of the pixel portion (cured product of the ink composition) from the viewpoint of preventing a decrease in transmittance. %.

  Hereinafter, the present invention will be described specifically with reference to examples. However, the present invention is not limited to only the following examples. It should be noted that all the materials used in the examples were obtained by introducing argon gas and replacing dissolved oxygen with argon gas. The titanium oxide used was heated at 175 ° C. for 4 hours under a reduced pressure of 1 mmHg and left to cool in an argon gas atmosphere before mixing. The liquid material used in the examples was dehydrated with a molecular sieve 3A for 48 hours or more before mixing before use.

<Preparation of photopolymerizable compound>
The following photopolymerizable compound was prepared.
AOMA (Methyl 2-allyloxymethyl acrylate, manufactured by Nippon Shokubai Co., Ltd., trade name: FX-AO-MA)
HDDMA (1,6-hexanediol dimethacrylate, manufactured by Shin-Nakamura Chemical Co., Ltd., trade name: NK Ester HD-N)
・ EOEOEA (ethoxyethoxyethyl acrylate, manufactured by MIWON, trade name: Miramer M170)

<Example 1>
(Preparation of InP / ZnSeS / ZnS Nanocrystalline Particle Dispersion with Green Emission)
[Synthesis of Green Emitting Nanocrystalline Particle Core (InP Core)]
5 g of trioctylphosphine oxide (TOPO), 1.46 g (5 mmol) of indium acetate and 3.16 g (15.8 mmol) of lauric acid were added to the reaction flask to obtain a mixture. The mixture was heated at 160 ° C. for 40 minutes under a nitrogen (N 2) environment, and then heated at 250 ° C. for 20 minutes under vacuum. Next, the reaction temperature (temperature of the mixture) was increased to 300 ° C. under a nitrogen (N 2) environment. At this temperature, a mixture of 3 g of 1-octadecene (ODE) and 0.25 g (1 mmol) of tris (trimethylsilyl) phosphine was quickly introduced into the reaction flask, maintaining the reaction temperature at 260 ° C. After 5 minutes, the reaction was stopped by removing the heater, and the resulting reaction solution was cooled to room temperature. Next, 8 ml of toluene and 20 ml of ethanol were added to the reaction solution in the glove box. Subsequently, after centrifugation was performed to precipitate InP nanocrystal particles (InP core), the supernatant was decanted to obtain InP nanocrystal particles (InP core). Next, the obtained InP nanocrystal particles (InP core) were dispersed in hexane to obtain a dispersion liquid (hexane dispersion liquid) containing 5% by mass of InP nanocrystal particles (InP core).

[Synthesis of green light-emitting nanocrystal particle shell (ZnSeS / ZnS shell)]
After adding 2.5 g of the hexane dispersion liquid of the InP nanocrystal particles (InP core) obtained above to the reaction flask, 0.7 g of oleic acid was added to the reaction flask at room temperature, and the temperature was raised to 80 ° C. Was. Then, 14 mg of diethylzinc, 8 mg of bis (trimethylsilyl) selenide and 7 mg of hexamethyldisilatiane (ZnSeS precursor solution) dissolved in 1 ml of ODE were dropped into the reaction mixture to form a 0.5 monolayer thick solution. A ZnSeS shell was formed.

  After the dropwise addition of the ZnSeS precursor solution, the reaction temperature was maintained at 80 ° C. for 10 minutes. Then the temperature was raised to 140 ° C. and held for 30 minutes. Next, into this reaction mixture, a ZnS precursor solution obtained by dissolving 69 mg of diethyl zinc and 66 mg of hexamethyldisilatiane in 2 ml of ODE was added dropwise to form a ZnS shell having a thickness of 2 monolayers. . Ten minutes after the dropwise addition of the ZnS precursor solution, the reaction was stopped by removing the heater. Next, the reaction mixture was cooled to room temperature, and the resulting white precipitate was removed by centrifugation, whereby a transparent nanocrystal particle dispersion (ODE dispersion liquid) in which green-emitting InP / ZnSeS / ZnS nanocrystal particles were dispersed was obtained. ) Got.

[Synthesis of Organic Ligands for InP / ZnSeS / ZnS Nanocrystal Particles]
(Synthesis of organic ligand)
Polyethylene glycol | average Mn400 | (manufactured by Sigma-Aldrich) is charged into a flask, and then stirred under a nitrogen gas environment, and succinic anhydride (Sigma-Aldrich company) in an equimolar amount to polyethylene glycol | average Mn400 | Was added. The internal temperature of the flask was raised to 80 ° C., and the mixture was stirred for 8 hours to obtain an organic ligand represented by the following formula (A) as a pale yellow viscous oil.

[Preparation of green light-emitting InP / ZnSeS / ZnS nanocrystal particle dispersion by ligand exchange]
30 mg of the organic ligand was added to 1 ml of the ODE dispersion of the InP / ZnSeS / ZnS nanocrystal particles obtained above. Next, ligand exchange was performed by heating at 90 ° C. for 5 hours. With the progress of the ligand exchange, aggregation of the nanocrystal particles was observed. After the ligand exchange, the supernatant was decanted to obtain nanocrystal particles. Then, 3 ml of ethanol was added to the obtained nanocrystal particles, and the mixture was ultrasonically dispersed to be redispersed. 10 ml of n-hexane was added to 3 ml of the ethanol dispersion liquid of the obtained nanocrystal particles. Subsequently, after nanocrystal particles were precipitated by centrifugation, the supernatant was decanted and dried under vacuum to obtain nanocrystal particles (InP / ZnSeS / ZnS nanocrystal particles modified with the organic ligand). The content of the organic ligand in the total amount of the nanocrystal particles modified with the organic ligand was 30% by mass. By dispersing the obtained nanocrystal particles (InP / ZnSeS / ZnS nanocrystal particles modified with the organic ligand) in a photopolymerizable compound so that the content in the dispersion becomes 50% by mass, A green light-emitting nanocrystal particle dispersion was obtained. AOMA was used as the photopolymerizable compound. The content of AOMA in the dispersion was 50% by mass.

(Preparation of light scattering particle dispersion)
In a container filled with argon gas, 33.0 g of titanium oxide (trade name: CR-60-2, manufactured by Ishihara Sangyo Co., Ltd., average particle diameter (volume average diameter): 210 nm) and a polymer dispersant (product) Name: Addispar PB-821, 1.0 g of Ajinomoto Fine Techno Co., Ltd.) and 26.0 g of AOMA were added, and zirconia beads (diameter: 1.25 mm) were added to the obtained mixture, and a paint conditioner was used. The mixture was dispersed by shaking for 2 hours, and the zirconia beads were removed with a polyester mesh filter to obtain a light scattering particle dispersion 1 (titanium oxide content: 55% by mass).

(Preparation of ink composition)
Green light-emitting nanocrystal particle dispersion, light scattering particle dispersion, and ethyl phenyl (2,4,6-trimethylbenzoyl) phosphinate (IGM resin, trade name: Omnirad TPO-) as a photopolymerization initiator L, molecular weight: 316) was mixed such that the content of each component in the ink composition became the content shown in Table 1, and mixed uniformly in a container filled with argon gas. Then, in a glove box, the mixture was filtered with a filter having a pore size of 3 μm. Further, argon gas was introduced into a container containing the obtained filtrate, and the inside of the container was saturated with argon gas. Next, the pressure was reduced to remove the argon gas, whereby the ink composition of Example 1 was obtained. The content of the luminescent nanocrystal particles shown in Table 1 includes the content of the organic ligand (7.7 parts by mass).

<Example 2>
In preparing the luminescent nanocrystal particle dispersion, AOMA and HDDMA were used as the photopolymerizable compounds, and the contents of each component in the ink composition were as shown in Table 1. The ink composition of Example 2 was prepared in the same manner as in Example 1 except that the respective components were blended.

<Example 3>
In preparing the ink composition, in addition to the green light-emitting nanocrystal particle dispersion, the light scattering particle dispersion, and the photopolymerization initiator, tetraethylene glycol bis (3-mercaptopropionate) ( SC Organic Chemical Co., Ltd., trade name: EGMP-4), 2-ethylhexyl diphenyl phosphite (ADEKA CORPORATION, Adekastab C) was used as an antioxidant, and in the ink composition The ink composition of Example 3 was prepared in the same manner as in Example 1, except that the components were blended so that the content of each component was as shown in Table 1.

<Comparative Example 1>
In preparing the luminescent nanocrystal particle dispersion, EOEOEA was used as the photopolymerizable compound instead of AOMA, and the content of each component in the ink composition was as shown in Table 2. An ink composition of Comparative Example 1 was prepared in the same manner as in Example 1 except that the components were blended as described above.

<Evaluation>
[Preparation of evaluation sample]
Each ink composition was applied on a glass substrate by a spin coater in the air so as to have a thickness of 10 μm. The coating film is irradiated with UV by a conveyer type UV irradiation device (trade name “UV3001DT-1C”) manufactured by Sen Engineering Co., Ltd. under a nitrogen atmosphere so as to have an integrated light amount of 1000 mJ / cm ² , and is cured. A layer (light conversion layer) composed of a cured product of the ink composition was formed. Thus, each evaluation sample, which is a substrate having a light conversion layer, was produced.

[External quantum efficiency (EQE) evaluation]
A blue LED (peak emission wavelength: 450 nm) manufactured by CCS Corporation was used as a surface emission light source. The measuring device was connected to an emission spectrophotometer (trade name “MCPD-9800”) manufactured by Otsuka Electronics Co., Ltd., and the integrating sphere was placed above the blue LED. The produced evaluation sample was inserted between the blue LED and the integrating sphere, and the spectrum observed when the blue LED was turned on and the illuminance at each wavelength were measured.

From the spectrum and the illuminance measured by the above measuring device, the external quantum efficiency was determined as follows. The external quantum efficiency is a value indicating how much of the light (photons) incident on the light conversion layer is emitted to the observer side as fluorescence. Therefore, when this value is large, it indicates that the light conversion layer is excellent in light emission characteristics, and is an important evaluation index.
EQE (%) = P1 (Green) / E (Blue) × 100

Here, E (Blue) and P1 (Green) represent the following, respectively.
E (Blue): represents a total value of “illuminance × wavelength ÷ hc” in a wavelength range of 380 to 490 nm.
P1 (Green): represents a total value of “illuminance × wavelength ÷ hc” in a wavelength range of 500 to 650 nm.
These are values corresponding to the number of observed photons. Note that h represents Planck's constant and c represents the speed of light.

The EQE measured immediately after preparing the evaluation sample is defined as an initial external quantum efficiency (EQE ₀ ). After the EQE ₀ is measured, the above-described evaluation sample is used as an acceleration test for measuring the EQE after a long period of time. Was tested in a glove box (trade name “Labmaster Pro DP”) manufactured by MBRAUN under a nitrogen atmosphere for one week. After the test, the external quantum efficiency (EQE _h ) was measured, and the EQE retention was calculated based on the following equation. The results are shown in Tables 1 and 2.
EQE maintenance rate = EQE _h / EQE ₀ × 100

[Viscosity evaluation]
After preparation, the ink composition was stored for one week in an environment of 23 ° C. and 50% RH. The viscosity of the stored ink composition was measured using an E-type viscometer. The viscosity measurement was performed at 25 ° C. The results are shown in Tables 1 and 2.

[Ejection stability evaluation]
After preparation, the ink composition was stored for one week in an environment of 23 ° C. and 50% RH. The stored ink composition was subjected to a discharge test using an inkjet printer (trade name “DMP-2831”, manufactured by Fuji Film Dimatix). In the ejection test, the ink composition was ejected continuously for 10 minutes at room temperature. In addition, 16 nozzles are formed in the head portion of the inkjet printer that discharges ink, and the amount of the ink composition used per discharge per nozzle is 10 pL. The ejection stability of the ink compositions of Examples and Comparative Examples was evaluated based on the following criteria. The results are shown in Tables 1 and 2.
A: Continuous discharge possible (continuous discharge possible with 10 or more nozzles out of 16 nozzles)
B: Continuous discharge impossible (the number of continuously dischargeable nozzles is 9 or less out of 16 nozzles)
C: No discharge

Reference numeral 10 denotes a pixel portion, 10a denotes a first pixel portion, 10b denotes a second pixel portion, 10c denotes a third pixel portion, 11a denotes a first light-emitting nanocrystal particle, and 11b denotes a second light-emitting nanocrystal particle. , 12a: first light scattering particles, 12b: second light scattering particles, 12c: third light scattering particles, 20: light shielding portion, 30: light conversion layer, 40: base material, 100: color filter.

Claims (15)

Luminescent nanocrystalline particles,
An allyl ether group, and a photopolymerizable compound containing an ethylenically unsaturated group capable of forming an intramolecular ring by reacting with the allyl ether group,
An ink composition containing The ink composition according to claim 1, wherein the photopolymerizable compound includes a structure represented by the following formula (II) as the structure having the ethylenically unsaturated group.

[In formula (II), * represents a bond. ]   The ink composition according to claim 1, further comprising a monofunctional or polyfunctional (meth) acrylate.   The ink composition according to any one of claims 1 to 3, wherein the content of the luminescent nanocrystal particles is more than 20% by mass based on the mass of the nonvolatile component of the ink composition.   The ink composition according to claim 1, further comprising a thiol compound.   The ink composition according to claim 1, further comprising an antioxidant.   The ink composition according to any one of claims 1 to 6, further comprising light scattering particles.   The ink composition according to any one of claims 1 to 7, wherein the content of the inorganic component is 30% by mass or more based on the mass of the nonvolatile components of the ink composition.   The ink composition according to any one of claims 1 to 8, which is used for forming a light conversion layer.   The ink composition according to any one of claims 1 to 9, which is used in an inkjet system.   A cured product of an ink composition containing luminescent nanocrystal particles and a polymer containing a structural unit having an ether ring. A plurality of pixel portions, and a light-shielding portion provided between the plurality of pixel portions,
A light conversion layer, wherein the plurality of pixel units include a light-emitting pixel unit including a cured product of the ink composition according to any one of claims 1 to 10 or a cured product according to claim 11. As the luminescent pixel portion,
A first luminescent pixel portion containing luminescent nanocrystalline particles that absorb light having a wavelength in the range of 420 to 480 nm and emit light having an emission peak wavelength in the range of 605 to 665 nm;
A second luminescent pixel portion containing luminescent nanocrystalline particles that absorb light having a wavelength in the range of 420 to 480 nm and emit light having an emission peak wavelength in the range of 500 to 560 nm;
The light conversion layer according to claim 12, comprising:   The light conversion layer according to claim 12, further comprising a non-light-emitting pixel portion containing light-scattering particles.   A color filter comprising the light conversion layer according to claim 12.

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