JP7331452B2 - Curable ink composition, light conversion layer and color filter - Google Patents

Description

The present invention relates to a curable ink composition, a light conversion layer and a color filter.

Conventionally, a pixel part (color filter pixel part) 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, an alkali-soluble resin and / or an acrylic monomer. It has been manufactured by photolithographic methods using materials.

In recent years, there has been a strong demand for lower power consumption of displays, and instead of the red organic pigment particles or green organic pigment particles, for example, quantum dots, quantum rods, and other inorganic phosphor particles. A method of forming pixel portions such as red pixels and green pixels using .

By the way, the manufacturing method of the color filter by the photolithography method has a drawback that the resist material other than the pixel portion including the relatively expensive luminescent nanocrystal particles is wasted due to the characteristics of the manufacturing method. Under these circumstances, in order to eliminate the waste of the resist material as described above, it is being investigated to form the pixel portion of the light conversion substrate using a curable ink composition by an inkjet method (inkjet method) ( Patent document 1).

WO2008/001693

From the viewpoint of low power consumption, external quantum efficiency (EQE: Further improvement of the External Quantum Efficiency is required.

One of the objects of the present invention is to provide a curable ink composition capable of forming color filter pixel portions with excellent external quantum efficiency.

The present inventors use a combination of a polyfunctional (meth)acrylic compound and a polyfunctional (meth)allyl compound as a curable component to be contained in a curable ink composition, thereby improving the luminous properties after curing. The inventors have found that it is possible to complete the present invention.

That is, one aspect of the present invention relates to a curable ink composition containing luminescent nanocrystalline particles, a polyfunctional (meth)acrylic compound, and a polyfunctional (meth)allyl compound.

According to the ink composition of the aspect, a color filter pixel portion having excellent external quantum efficiency can be formed.

In one aspect, the polyfunctional (meth)allyl compound may have a benzene ring.

In one aspect, the polyfunctional (meth)allyl compound can be a difunctional or trifunctional (meth)allyl compound.

In one aspect, the polyfunctional (meth)allyl compound may have a (meth)allyloxy group.

In one aspect, the polyfunctional (meth)allyl compound may have a molecular weight of 100-300.

In one aspect, the polyfunctional (meth)allyl compound may be a compound represented by formula (I) below.
[In formula (I), n represents 2 or 3, and multiple R ^1s each independently represent a hydrogen atom or a methyl group. ]

In one aspect, the polyfunctional (meth)acrylic compound can be a difunctional or trifunctional (meth)acrylic compound.

In one aspect, the polyfunctional (meth)acrylic compound may have a molecular weight of 50-700.

In one aspect, the polyfunctional (meth)acrylic compound may be a (poly)alkylene glycol di(meth)acrylate.

In one aspect, the curable ink composition may further contain light scattering particles.

In one aspect, the curable ink composition may further contain a phosphite triester.

In one aspect, the curable ink composition can be used to form a light conversion layer. That is, the curable ink composition may be an ink composition for forming a light conversion layer.

In one aspect, the curable ink composition can be used in inkjet mode. That is, the curable ink composition may be a curable inkjet ink.

Another 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 contains a cured product of the curable ink composition described above. It relates to a light conversion layer having a luminescent pixel portion.

In one aspect, the light conversion layer contains luminescent nanocrystalline particles that absorb light with a wavelength in the range of 420 to 480 nm and emit light with an emission peak wavelength in the range of 605 to 665 nm as the luminescent pixel portion. a first luminescent pixel portion; and a second luminescent pixel containing luminescent nanocrystalline particles that absorb light with a wavelength in the range of 420-480 nm and emit light with an emission peak wavelength in the range of 500-560 nm. and .

In one aspect, the light conversion layer may further comprise non-emissive pixel portions containing light scattering particles.

Another aspect of the invention relates to a color filter comprising the light conversion layer described above.

ADVANTAGE OF THE INVENTION According to this invention, the curable ink composition which can form the color filter pixel part which has the outstanding external quantum efficiency, and the light conversion layer and color filter using the said ink composition can be provided.

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

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail. In this specification, a numerical range indicated using "-" indicates a range including the numerical values before and after "-" as the minimum and maximum values, respectively. In the present specification, the term “cured product of the ink composition” refers to a product obtained by curing a curable component in the ink composition (when the ink composition contains a solvent component, the ink composition after drying). It is something that can be done. The cured ink composition after drying may not contain an organic solvent.

<Curable ink composition>
A curable ink composition of one embodiment (hereinafter also simply referred to as “ink composition”) comprises luminescent nanocrystalline particles, a polyfunctional (meth)acrylic compound, and a polyfunctional (meth)allyl compound. contains. The ink composition is, for example, photocurable or thermally polymerizable, and curable components in the ink composition (for example, polyfunctional (meth)acrylic compounds, polyfunctional (meth)acrylic compounds, polyfunctional (meth)acrylic compounds, etc. ) a polymerizable compound such as an allyl compound) reacts (for example, polymerizes) and cures.

The ink composition is, for example, an ink composition for forming a light conversion layer (for example, for forming a pixel portion of a color filter) used for forming a pixel portion of a light conversion layer of a color filter or the like. According to the ink composition, it is possible to form a color filter pixel portion having excellent external quantum efficiency. Moreover, according to the ink composition, it is easy to obtain excellent ejection stability in the inkjet method. That is, the ink composition can be suitably used for the inkjet method.

By the way, since the pixel portion is used in an environment exposed to light, it is required that the external quantum efficiency is not lowered by light (light resistance). In this case, it cannot necessarily be said that a pixel portion having sufficient lightfastness can be obtained. On the other hand, the ink composition tends to suppress the decrease in external quantum efficiency due to the light. That is, according to the ink composition, it is easy to form a pixel portion having excellent light resistance.

Although the reason why the above-described effects are obtained by the ink composition is not clear, compared to polyfunctional (meth)acrylic compounds that undergo polymerization reaction via unstable, highly reactive and highly active radicals, polyfunctional ( Since the meta)allyl compound undergoes a polymerization reaction via stable radicals, it is speculated that deactivation of the luminescent nanocrystalline particles (for example, quantum dots) is suppressed as a result.

The ink composition of one embodiment can be applied as an ink used in a known and commonly used method for manufacturing a color filter, without wasting relatively expensive materials such as luminescent nanocrystalline particles and solvents. In view of the fact that the pixel portion (light conversion layer) can be formed only by using the required amount at the required location, it is preferable to prepare and use it appropriately for the inkjet method rather than for the photolithographic method.

Hereinafter, the curable ink composition of one embodiment will be described by taking a curable ink composition for color filters (curable inkjet ink for color filters) used in an inkjet method as an example. The ink composition described below contains other components such as organic ligands, light-scattering particles, and organic solvents in addition to the luminescent nanocrystalline particles, the polyfunctional (meth)acrylic compound, and the polyfunctional (meth)allyl compound. It can contain further.

[Luminescent nanocrystalline particles]
Luminescent nanocrystalline particles are nano-sized crystals that absorb excitation light and emit fluorescence or phosphorescence. For example, the maximum particle diameter measured by a transmission electron microscope or scanning electron microscope is 100 nm or less. It is crystalline.

Luminescent nanocrystalline particles can, for example, emit light (fluorescence or phosphorescence) at a wavelength different from the absorbed wavelength by absorbing light of a given wavelength. The luminescent nanocrystalline particles may be red luminescent nanocrystalline particles (red luminescent nanocrystalline particles) that emit light having an emission peak wavelength in the range of 605-665 nm (red light), Green luminescent nanocrystalline particles (green luminescent nanocrystalline particles) that emit light with an emission peak wavelength in the range of 420-480 nm (blue light). ), may be blue-emitting nanocrystalline particles (blue-emitting nanocrystalline particles). In this embodiment, the ink composition preferably contains at least one of these luminescent nanocrystalline particles. In addition, the light absorbed by the luminescent nanocrystalline particles is, for example, light with a wavelength in the range of 400 nm or more and less than 500 nm (especially light in the wavelength range of 420 to 480 nm) (blue light), or in the range of 200 nm to 400 nm. (ultraviolet light). The emission peak wavelength of the luminescent nanocrystalline particles can be confirmed, for example, in the fluorescence spectrum or phosphorescence spectrum measured using a spectrofluorometer.

The red-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, preferably 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 combined arbitrarily. In addition, in the following similar description, the upper limit and the lower limit that are individually described can be arbitrarily combined.

Green-emitting nanocrystalline particles have an emission peak wavelength of 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 preferably has an emission peak wavelength of 528 nm or more, 525 nm or more, 523 nm or more, 520 nm or more, 515 nm or more, 510 nm or more, 507 nm or more, 505 nm or more, 503 nm or more, or 500 nm or more.

The blue-emitting nanocrystalline particles have an emission peak wavelength of 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 preferably has an emission peak wavelength of 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 Schrödinger wave equation of the well-type potential model, the wavelength (emission color) of the light emitted by the luminescent nanocrystalline particles depends on the size (e.g., particle diameter) of the luminescent nanocrystalline 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 nanocrystalline particles used.

The luminescent nanocrystalline particles may be luminescent nanocrystalline particles comprising semiconductor materials (luminescent semiconductor nanocrystalline particles). Luminescent semiconductor nanocrystal particles include quantum dots and quantum rods. Among these, quantum dots are preferable from the viewpoint that the emission spectrum can be easily controlled, the reliability can be secured, the production cost can be reduced, and the mass productivity can be improved.

The luminescent semiconductor nanocrystal particles may consist only of a core comprising the first semiconductor material, comprising a core comprising the first semiconductor material and a second semiconductor material different from the first semiconductor material, wherein and a shell covering at least a portion of the core. In other words, the structure of the luminescent semiconductor nanocrystal particles may be a structure consisting of only a core (core structure) or a structure consisting of a core and a shell (core/shell structure). In addition, the luminescent semiconductor nanocrystal particle contains a third semiconductor material different from the first and second semiconductor materials in addition to the shell (first shell) containing the second semiconductor material, It may further have a shell (second shell) that covers at least part of it. In other words, the structure of the luminescent semiconductor nanocrystal particles may be a structure consisting of a core, a first shell and a second shell (core/shell/shell structure). Each of the core and shell may be a mixed crystal containing two or more semiconductor materials (eg, CdSe+CdS, CIS+ZnS, etc.).

Luminescent nanocrystalline particles are selected as semiconductor materials from the group consisting of II-VI semiconductors, III-V semiconductors, I-III-VI semiconductors, IV semiconductors and I-II-IV-VI semiconductors. It preferably contains at least one semiconductor material that

Specific semiconductor materials include CdS, CdSe, CdTe, ZnS, ZnSe, ZnTe, ZnO, HgS, HgSe, HgTe, CdSeS, CdSeTe, CdSTe, ZnSeS, ZnSeTe, ZnSTe, HgSeS, HgSeTe, HgSTe, CdZnS, CdZnSe, CdZnTe, CdHgS, CdHgSe, CdHgTe, HgZnS, HgZnSe, CdHgZnTe, CdZnSeS, CdZnSeTe, CdZnSTe, CdHgSeS, CdHgSeTe, CdHgSTe, HgZnSeS, HgZnSeTe, HgZnSTe; GaN, GaP, GaAs, GaSb, AlN, AlP, AlAs, AlSb, InN, InP, InAs, InSb, GaNP, GaNAs, GaNSb, GaPAs, GaPSb, AlNP, AlNAs, AlNSb, AlPAs, AlPSb, InNP, InNAs, InNSb, InPAs, InPSb, GaAlNP, GaAlNAs, GaAlNSb, GaAlPAs, GaAlPSb, GaInNP, GaInNAs, GaInNSb, GaInPAs, GaInPSb, InAlNP, InAlNAs, InAlNSb, InAlPAs, InAlPSb; SnS, SnSe, SnTe, PbS, PbSe, PbTe, SnSeS, SnSeTe, SnSTe, PbSeS, PbSeTe, PbSTe, SnPbS, SnPbSe , SnPbTe, SnPbSSe, SnPbSeTe, SnPbSTe; includes Si, Ge, SiC, SiGe, _AgInSe2 , CuGaSe2, CuInS2, _CuGaS2 , _CuInSe2 , _{AgInS2 ,} AgGaSe2, _{AgGaS2 , C} , Si and Ge. Luminescent semiconductor nanocrystalline particles are CdS, CdSe, CdTe, ZnS, and CdS, CdSe, CdTe, ZnS, and CdS, CdSe, CdTe, ZnS, and CdS, CdSe, CdTe, ZnS, and CdS. ZnSe, ZnTe, ZnO, _HgS , HgSe, _HgTe , InP, InAs, InSb, GaP, GaAs, _GaSb , _AgInS2 , AgInSe2 _, AgInTe2, AgGaS2, AgGaSe2, _AgGaTe2 , _CuInS2 , CuInSe2 _{, CuInTe2} , CuGaS ₂ , CuGaSe ₂ , CuGaTe ₂ , Si, C, Ge and Cu ₂ ZnSnS ₄ .

Examples of red-emitting semiconductor nanocrystal particles include nanocrystal particles of CdSe and nanocrystal particles having a core/shell structure in which the shell portion is CdS and the inner core portion is CdSe. particles, nanocrystalline particles with a core/shell structure, where the shell portion is CdS and the inner core portion is ZnSe, mixed crystal nanocrystalline particles of CdSe and ZnS, InP nanocrystalline particles A crystalline particle, a nanocrystalline particle with a core/shell structure, wherein the shell portion is ZnS and the inner core portion is InP, a nanocrystalline particle with a core/shell structure, Nanocrystalline particles whose shell portion is a mixed crystal of ZnS and ZnSe and whose inner core portion is InP, nanocrystalline particles of mixed crystal of CdSe and CdS, nanocrystalline particles of mixed crystal of ZnSe and CdS, core /Nanocrystalline particles with a shell/shell structure, wherein the first shell portion is ZnSe, the second shell portion is ZnS, and the inner core portion is InP, core/shell / A nanocrystalline particle having a 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 is InP etc.

Examples of green-emitting semiconductor nanocrystalline particles include nanocrystalline particles of CdSe, nanocrystalline particles of a mixed crystal of CdSe and ZnS, and nanocrystalline particles having a core/shell structure, the shell portion of which is ZnS. and a nanocrystalline particle having an inner core of InP, a nanocrystalline particle having a core/shell structure, wherein the shell is a mixed crystal of ZnS and ZnSe and the inner core is InP Crystalline particles, nanocrystalline particles with 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 nanocrystalline particle with 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 is InP certain nanocrystalline particles and the like.

Examples of blue-emitting semiconductor nanocrystalline particles include ZnSe nanocrystalline particles, ZnS nanocrystalline particles, and nanocrystalline particles having a core/shell structure, wherein the shell portion is ZnSe and the inner core portion is is ZnS, nanocrystalline particles of CdS, nanocrystalline particles having a core/shell structure, wherein the shell portion is ZnS and the inner core portion is InP, core/shell A nanocrystalline particle with a structure, wherein the shell part is a mixed crystal of ZnS and ZnSe and the inner core part is InP, a nanocrystalline particle with a core/shell/shell structure. a nanocrystalline particle having a first shell portion of ZnSe, a second shell portion of ZnS, and an inner core portion of InP, a nanocrystalline particle having a core/shell/shell structure, Examples include nanocrystalline particles in which the first shell portion is a mixed crystal of ZnS and ZnSe, the second shell portion is ZnS, and the inner core portion is InP.

With the same chemical composition, the semiconductor nanocrystal particles can change the color to be emitted from the particles to either red or green by changing the average particle size of the particles themselves. In addition, it is preferable to use semiconductor nanocrystal particles that themselves have the least adverse effect on the human body or the like. When semiconductor nanocrystal particles containing cadmium, selenium, etc. are used as luminescent nanocrystal particles, semiconductor nanocrystal particles that do not contain the above elements (cadmium, selenium, etc.) as much as possible are selected and used alone. is preferably used in combination with other luminescent nanocrystalline particles so as to minimize the

The shape of the luminescent nanocrystalline particles is not particularly limited and may be any geometric shape or any irregular shape. The shape of the luminescent nanocrystalline particles may be, for example, spherical, ellipsoidal, pyramidal, disk-like, branch-like, net-like, rod-like, and the like. However, as the luminescent nanocrystalline particles, the uniformity and fluidity of the ink composition can be further improved by using particles with a less directional particle shape (e.g., spherical, regular tetrahedral particles, etc.). is preferred.

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

From the viewpoint of dispersion stability, the luminescent nanocrystalline particles preferably have organic ligands on their surfaces. Organic ligands may be coordinated to the surface of the luminescent nanocrystalline particles, for example. In other words, the surface of the luminescent nanocrystalline particles may be passivated by organic ligands. Moreover, when the ink composition further contains a polymer dispersant, which will be described later, the luminescent nanocrystalline particles may have the polymer dispersant on their surfaces. In this embodiment, for example, the organic ligand is removed from the luminescent nanocrystalline particles having the above-described organic ligand, and the organic ligand is exchanged with the polymeric dispersant, thereby dispersing the polymeric dispersant on the surface of the luminescent nanocrystalline particles. may be combined. However, from the viewpoint of dispersion stability when used as an inkjet ink, it is preferable that a polymer dispersant is added to the luminescent nanocrystalline particles with the organic ligands still coordinated.

As the organic ligand, a functional group (hereinafter simply referred to as "affinity group") for ensuring affinity with polyfunctional (meth)acrylic compounds, polyfunctional (meth)allyl compounds, organic solvents, etc., It is preferably a compound having a functional group capable of bonding with the luminescent nanocrystalline particles (a functional group for ensuring adsorption to the luminescent nanocrystalline particles). The affinity group may be a substituted or unsubstituted aliphatic hydrocarbon group. The aliphatic hydrocarbon group may be linear or have a branched structure. Also, the aliphatic hydrocarbon group may or may not have an unsaturated bond. The substituted aliphatic hydrocarbon may be a group in which some carbon atoms of an aliphatic hydrocarbon group are substituted with oxygen atoms. Substituted aliphatic hydrocarbon groups may include, for example, (poly)oxyalkylene groups. 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 linked by an ether bond. Functional groups that can bind to luminescent nanocrystalline particles include, for example, hydroxyl groups, amino groups, carboxyl groups, thiol groups, phosphate groups, phosphonic acid groups, phosphine groups, phosphine oxide groups, and alkoxysilyl groups. Examples of organic ligands 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).

［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 formula (1-1) below.

[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 formula (1-1), at least one of p and q is preferably 1 or more, more preferably both p and q are 1 or more.

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

In 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 is 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, two or more and four or less, or two. The number of carbon atoms in the alkylene group represented by L may be, for example, 1-10. In the alkylene group represented by L, some of the carbon atoms may be substituted with hetero atoms, and at least one hetero atom selected from the group consisting of oxygen atoms, sulfur atoms and nitrogen atoms. good too. r may be, for example, an integer of 1-100, or an integer of 10-20.

The organic ligand may be an organic ligand represented by the following formula (1-2A) from the viewpoint of excellent external quantum efficiency of the pixel portion (cured product of the ink composition).

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

The content of the organic ligand in the ink composition is 15 parts by mass or more and 20 parts by mass with respect to 100 parts by mass of the luminescent nanocrystalline particles from the viewpoint of the dispersion stability of the luminescent nanocrystalline particles and the maintenance of the light emission properties. Above, it may be 25 parts by mass or more, 30 parts by mass or more, 35 parts by mass or more, or 40 parts by mass or more. From the viewpoint of keeping the viscosity of the ink composition low, the content of the organic ligand in the ink composition is 50 parts by mass or less, 45 parts by mass or less, or 40 parts by mass or less relative to 100 parts by mass of the luminescent nanocrystalline particles. It may be 30 parts by mass or less.

As the luminescent nanocrystalline particles, those dispersed in a colloidal form in a polymerizable compound, an organic solvent, or the like can be used. The surfaces of the luminescent nanocrystalline particles dispersed in the organic solvent are preferably passivated with the above-described organic ligands. As the organic solvent, the below-described organic solvent contained in the ink composition is used.

Commercially available products can be used as the luminescent nanocrystalline particles. Commercially available luminescent nanocrystalline particles include, for example, indium phosphide/zinc sulfide, D-dot, CuInS/ZnS from NN-Labs, and InP/ZnS from Aldrich.

From the viewpoint of further improving the external quantum efficiency of the pixel portion, the content of the luminescent nanocrystalline particles is preferably 5 parts by mass or more with respect to the total 100 parts by mass of the components other than the organic solvent contained in the ink composition. Yes, it may be 10 parts by mass or more, 15 parts by mass or more, 20 parts by mass or more, or 30 parts by mass or more. From the viewpoint of further improving the ejection stability and the external quantum efficiency of the pixel portion, the content of the luminescent nanocrystalline particles is preferably 80 parts by mass or less with respect to the total of the components other than the organic solvent contained in the ink composition. and may be 75 parts by mass or less, 70 parts by mass or less, or 60 parts by mass or less. In this specification, the term "components other than the organic solvent contained in the ink composition" may also be referred to as components to be contained in the cured product of the ink composition. When the ink composition contains luminescent nanocrystalline particles, an organic ligand, a polymerizable compound, light-scattering particles, and an organic solvent, the "total of components other than the organic solvent contained in the ink composition" can be the sum of luminescent nanocrystalline particles, organic ligands, polymerizable compounds, and light scattering particles.

The content of the luminescent nanocrystalline particles based on the total mass of the ink composition is preferably 15% by mass or more, 18% by mass or more, or 20% by mass or more from the viewpoint of further improving the external quantum efficiency. may The content of the luminescent nanocrystalline particles based on the total mass of the ink composition is preferably 35% by mass or less, 32% by mass or less, or 30% by mass from the viewpoint of improving ejection stability and external quantum efficiency. It may be below.

The ink composition may contain, as luminescent nanocrystalline particles, two or more of red luminescent nanocrystalline particles, green luminescent nanocrystalline particles and blue luminescent nanocrystalline particles, but these are preferably used. It contains only one type of particles. When the ink composition comprises red-emitting nanocrystalline particles, the content of green-emitting nanocrystalline particles and the content of blue-emitting nanocrystalline particles are preferably 10, based on the total weight of the luminescent nanocrystalline particles. % by mass or less, more preferably 0% by mass. When the ink composition comprises green luminescent nanocrystalline particles, the content of red luminescent nanocrystalline particles and the content of blue luminescent nanocrystalline particles, based on the total mass of luminescent nanocrystalline particles, is preferably 10. % by mass or less, more preferably 0% by mass.

[Polyfunctional (meth)acrylic compound]
A polyfunctional (meth)acrylic compound is a compound having two or more (meth)acryloyl groups. In this specification, "(meth)acryl" means "acryl" and "methacryl" corresponding thereto. The same applies to the expression "(meth)acryloyl" and the expression "(meth)acrylate".

The polyfunctional (meth)acrylic compound is preferably a bifunctional or trifunctional (meth)acrylic compound. That is, the polyfunctional (meth)acrylic compound preferably has two or three (meth)acryloyl groups.

The polyfunctional (meth)acrylic compound may be (poly)alkylene glycol di(meth)acrylate from the viewpoint of facilitating the formation of a pixel portion having excellent initial external quantum efficiency and light resistance. (Poly)alkylene glycol di(meth)acrylate means monoalkylene glycol di(meth)acrylate or polyalkylene glycol di(meth)acrylate. The alkylene group may be linear or branched.

Examples of monoalkylene glycol di(meth)acrylates include ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, 1,3-butylene glycol di(meth)acrylate, 1,4-butanediol di(meth)acrylate. ) acrylate, 1,5-pentanediol di(meth)acrylate, 3-methyl-1,5-pentanediol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, neopentyl glycol di(meth)acrylate acrylate, 1,8-octanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate and the like.

Examples of polyalkylene glycol di(meth)acrylates include polyethylene glycol di(meth)acrylate, polypropylene glycol di(meth)acrylate (dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate, etc.), neo Di(meth)acrylate obtained by adding 4 mol or more of ethylene oxide or propylene oxide to 1 mol of pentyl glycol and two hydroxyl groups of the diol are substituted with (meth)acryloyloxy groups, 3 per 1 mol of trimethylolpropane A di(meth)acrylate obtained by adding ethylene oxide or propylene oxide in a molar amount or more and two hydroxyl groups of a triol substituted with a (meth)acryloyloxy group.

The polyfunctional (meth)acrylic compound may have a benzene ring. When the polyfunctional (meth)acrylic compound has a benzene ring, the external quantum efficiency of the pixel portion tends to be excellent. In addition, when the polyfunctional (meth)acrylic compound has a benzene ring, the polymer containing the structure derived from the polyfunctional (meth)acrylic compound generated by curing the ink composition tends to have a rigid structure, which increases the durability of the pixel portion. tend to be superior to Such polyfunctional acrylic compounds include, for example, di(meth)acryloyloxy substituted with (meth)acryloyloxy groups for two hydroxyl groups of a diol obtained by adding 2 moles of ethylene oxide or propylene oxide to 1 mol of bisphenol A. ) acrylates, di(meth)acrylates obtained by adding 4 mol or more of ethylene oxide or propylene oxide to 1 mol of bisphenol A, and two hydroxyl groups of the diol are substituted with (meth)acryloyloxy groups.

Among the above, 1,6-hexanediol di(meth)acrylate, 1,9-nonanediol di(meth)acrylate, dipropylene glycol di(meth)acrylate, tripropylene glycol di(meth)acrylate and neopentyl glycol di(meth)acrylate. At least one selected from the group consisting of (meth)acrylates is preferred.

In addition to the above, polyfunctional (meth)acrylic compounds include, for example, tricyclodecanedimethanol di(meth)acrylate, neopentylglycol hydroxypivalate diacrylate, tris(2-hydroxyethyl)isocyanurate Difunctional (meth)acrylates such as di(meth)acrylate in which two hydroxyl groups are substituted by (meth)acryloyloxy groups; trifunctional ( meth)acrylate and the like. A polyfunctional (meth)acryl compound may be used individually by 1 type or in combination of 2 or more types.

The polyfunctional (meth)acrylic compound may be alkali-insoluble from the viewpoint of easily obtaining a highly reliable pixel portion. As used herein, the term “alkali-insoluble” means that the amount of a compound dissolved in a 1% by mass aqueous potassium hydroxide solution at 25° C. is 30% by mass or less based on the total mass of the compound. The dissolved amount of the polyfunctional (meth)acrylic compound is preferably 10% by mass or less, more preferably 3% by mass or less.

The molecular weight of the polyfunctional (meth)acrylic compound may be 700 or less, 500 or less, or 400 or less from the viewpoint of viscosity, and may be 50 or more, 100 or more, 150 or more, or 200 or more from the volatility viewpoint. .

The content of the polyfunctional (meth)acrylic compound is 20 parts by mass or more and 30 parts by mass with respect to the total 100 parts by mass of the components other than the organic solvent contained in the ink composition, from the viewpoint of better external quantum efficiency of the pixel portion. parts or more, or 40 parts by mass or more. The content of the polyfunctional (meth)acrylic compound is 70 parts by mass or less and 60 parts by mass with respect to the total 100 parts by mass of the components other than the organic solvent contained in the ink composition, from the viewpoint of better external quantum efficiency of the pixel portion. parts or less or 55 parts by mass or less.

[Polyfunctional (meth)allyl compound]
A polyfunctional (meth)allyl compound is a compound having two or more (meth)allyl groups. In this specification, "(meth)allyl" means "allyl" and "methallyl" corresponding thereto.

The polyfunctional (meth)allyl compound is preferably a bifunctional or trifunctional (meth)allyl compound. That is, the number of (meth)allyl groups possessed by the polyfunctional (meth)allyl compound is preferably two or three. A (meth)allyl group may be bonded to a heteroatom such as an oxygen atom, a sulfur atom, or a nitrogen atom.

The (meth)allyl group possessed by the polyfunctional (meth)allyl compound may be contained in the polyfunctional (meth)allyl compound as part of the (meth)allyloxy group or (meth)allyloxycarbonyl group. When the polyfunctional (meth)allyl compound has a (meth)allyloxy group, the external quantum efficiency of the pixel portion tends to be superior. When the polyfunctional (meth)allyl compound has a (meth)allyloxycarbonyl group, the external quantum efficiency of the pixel portion tends to be even better. The number of (meth)allyloxy groups may be two or three, and the number of (meth)allyloxycarbonyl groups may be two or three.

The polyfunctional (meth)allyl compound preferably has a benzene ring from the viewpoint of improving the external quantum efficiency of the pixel portion. In addition, when the polyfunctional (meth)allyl compound has a benzene ring, the polymer containing the structure derived from the polyfunctional (meth)allyl compound generated by curing the ink composition tends to have a rigid structure, which increases the durability of the pixel portion. tend to be superior to

The polyfunctional (meth)allyl compound may be, for example, a poly(meth)allyl ester compound obtained by adding (or condensing) 2 mol or more of (meth)allyl alcohol to 1 mol of polycarboxylic acid. Polycarboxylic acids may be dicarboxylic or tricarboxylic acids. Polycarboxylic acids may be either saturated or unsaturated, and either aliphatic or aromatic. The aliphatic polycarboxylic acid may be linear or molecular chain. Examples of polycarboxylic acids include succinic acid, adipic acid, glutaric acid, fumaric acid, maleic acid, phthalic acid, isophthalic acid, terephthalic acid, and trimesic acid.

The polycarboxylic acid is preferably phthalic acid, isophthalic acid, terephthalic acid, or trimesic acid from the viewpoint of facilitating formation of a pixel portion having excellent initial external quantum efficiency and light resistance. That is, the polyfunctional (meth)allyl compound is preferably a compound represented by the following formula (I).
[In formula (I), n represents 2 or 3, and multiple R ^1s each independently represent a hydrogen atom or a methyl group. ]

The compound represented by formula (I) is preferably a compound represented by formula (Ia) below.

In addition to the above, polyfunctional (meth)allyl compounds include allyl ether (3-(allyloxy)-1-propene), glycerol α,α'-diallyl ether (1,3-diallyloxy-2-propanol), trimethylol Poly(meth)allyl ether compounds such as propane diallyl ether may also be used. The polyfunctional (meth)allyl compound may be a compound having an isocyanurate ring such as triallyl isocyanurate. tend to be less sexual. A polyfunctional (meth)allyl compound may be used individually by 1 type or in combination of 2 or more types.

The polyfunctional (meth)allyl compound may be alkali-insoluble from the viewpoint of easily obtaining a highly reliable pixel portion. The amount of the polyfunctional (meth)allyl compound dissolved in a 1% by mass aqueous potassium hydroxide solution at 25° C. is preferably 10% by mass or less, more preferably 3% by mass or less.

The molecular weight of the polyfunctional (meth)allyl compound may be 300 or less, or 250 or less from the viewpoint of viscosity, and may be 100 or more, or 200 or more from the volatility viewpoint.

The content of the polyfunctional (meth)allyl compound is 1 part by mass or more and 5 parts by mass with respect to a total of 100 parts by mass of the components other than the organic solvent contained in the ink composition, from the viewpoint of better external quantum efficiency of the pixel portion. parts or more, or 8 parts by mass or more. The content of the polyfunctional (meth)allyl compound is 20 parts by mass or less and 15 parts by mass with respect to a total of 100 parts by mass of the components other than the organic solvent contained in the ink composition, from the viewpoint of better external quantum efficiency of the pixel portion. parts or less or 12 parts by mass or less.

The content of the polyfunctional (meth)allyl compound is 5 parts by mass or more, 10 parts by mass or more with respect to 100 parts by mass of the polyfunctional (meth)acrylic compound, or It may be 15 parts by mass or more. The content of the polyfunctional (meth)allyl compound is 40 parts by mass or less, 30 parts by mass or less with respect to 100 parts by mass of the polyfunctional (meth)acrylic compound, or It may be 25 parts by mass or less.

[Polymerization initiator]
The ink composition may further contain a polymerization initiator. The polymerization initiator may be a photoinitiator (eg, photoradical polymerization initiator) or a thermal polymerization initiator (eg, thermal radical polymerization initiator). Among these, photoradical polymerization initiators are preferable, and molecular cleavage type or hydrogen abstraction type photoradical polymerization initiators are more preferable.

Molecular cleavage type photoradical polymerization initiators 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 molecular cleavage type radical photopolymerization initiators include 1-hydroxycyclohexylphenyl 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.

Hydrogen abstraction photoradical polymerization initiators include benzophenone, 4-phenylbenzophenone, isophthalphenone, 4-benzoyl-4'-methyl-diphenylsulfide and the like. A molecular cleavage type radical photopolymerization initiator and a hydrogen abstraction type photoradical polymerization initiator may be used in combination.

A commercial item can also be used as a photoradical polymerization initiator. Commercially available products include acylphosphine oxide compounds such as "Omnirad TPO-H", "Omnirad TPO-L" and "Omnirad 819" manufactured by IGM Resin, and "Irgacure OXE01" and "Irgacure OXE02" manufactured by BASF. and alkylphenone compounds such as "Omnirad 1173", "Omnirad 907", "Omnirad 379EG" and "Omnirad 184" manufactured by IGM Resin. These may be used alone or in combination.

From the viewpoint of curability of the ink composition, the content of the polymerization initiator may be 0.1 parts by mass or more, or may be 0.5 parts by mass or more with respect to 100 parts by mass of the polymerizable compound. , 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, 30 parts by mass or less, or 20 parts by mass with respect to 100 parts by mass of the polymerizable compound, from the viewpoint of the temporal stability of the pixel portion. parts or less, or 10 parts by mass or less.

[Light scattering particles]
The ink composition may further contain light scattering particles. Light-scattering particles are, for example, optically inactive inorganic fine particles. When the ink composition contains light-scattering particles, it is possible to scatter the light emitted from the light source with which the pixel portion is irradiated, so that excellent optical properties can be obtained.

Materials constituting the light-scattering particles include, for example, simple metals 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 metal salts such as 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 an excellent effect of improving external quantum efficiency. It preferably contains at least one selected, and more preferably contains at least one selected from the group consisting of titanium oxide, zirconium oxide, zinc oxide and barium titanate.

The shape of the light-scattering particles may be spherical, filamentous, amorphous, or the like. However, as the light-scattering particles, the use of particles having a less directional particle shape (e.g., spherical, regular tetrahedral particles, etc.) improves the uniformity, fluidity, and light-scattering properties of the ink composition. It is preferable in that it can be increased and excellent ejection stability can be obtained.

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 an excellent effect of improving the external quantum efficiency. , 0.2 μm (200 nm) or more, or 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. It 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 0.0 μm, 0.2-0.6 μm, 0.2-0.4 μm, 0.3-1.0 μm, 0.3-0.6 μm, or 0.3-0.4 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. may In this 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 meter and calculating the volume average diameter. . The average particle size (volume average size) of the light-scattering particles to be used can be obtained by measuring the particle size of each particle with, for example, a transmission electron microscope or scanning electron microscope and calculating the volume average size.

The content of the light-scattering particles in the ink composition is 0.1 parts by mass or more with respect to the total 100 parts by mass of the components other than the organic solvent contained in the ink composition, from the viewpoint of improving the external quantum efficiency. , may be 1 part by mass or more, or may be 3 parts by mass or more. The content of the light-scattering particles is 60 parts by mass with respect to the total 100 parts by mass of the components other than the organic solvent contained in the ink composition, from the viewpoint of excellent ejection stability and an excellent effect of improving the external quantum efficiency. 50 parts by mass or less, 40 parts by mass or less, 30 parts by mass or less, 25 parts by mass or less, or 20 parts by mass or less or 15 parts by mass or less.

The content of the light-scattering particles based on the total mass of the ink composition is preferably 3% by mass or more, 4% by mass or more, or 7% by mass or more, from the viewpoint of further improving the external quantum efficiency of the pixel portion. may be The content of the light-scattering particles based on the total mass of the ink composition is preferably 20% by mass or less from the viewpoint of further improving the external quantum efficiency of the pixel portion and further improving the ejection stability. , 18% by mass or less, or 15% by mass or less.

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

The total amount of the luminescent nanocrystalline particles and the light-scattering particles in the ink composition is 100 parts by mass in total of the components other than the organic solvent contained in the ink composition, from the viewpoint of easily obtaining an appropriate viscosity as an inkjet ink. , preferably 20 parts by mass or more, more preferably 25 parts by mass or more, and still more preferably 30 parts by mass or more. The total amount of the luminescent nanocrystalline particles and the light-scattering particles in the ink composition is 100 parts by mass in total of the components other than the organic solvent contained in the ink composition, from the viewpoint of easily obtaining an appropriate viscosity as an inkjet ink. , preferably 75 parts by mass or less, more preferably 65 parts by mass or less, and even more preferably 55 parts by mass or less.

[Polymer dispersant]
The ink composition may further contain a polymeric dispersant. A polymeric dispersant is a polymeric compound having a weight average molecular weight of 750 or more and having a functional group having an affinity for light scattering particles. The polymer dispersant has a function of dispersing the light scattering particles. The polymer dispersant adsorbs to the light-scattering particles via a functional group having affinity for the light-scattering particles, and the light-scattering particles are dispersed by electrostatic repulsion and/or steric repulsion between the polymer dispersants. Disperse in the ink composition. 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 satisfactorily. can. The polymer dispersant is preferably bound to the surface of the light-scattering particles and adsorbed to the light-scattering particles. may be free in the ink composition.

Functional groups that have an affinity for light scattering particles include acidic functional groups, basic functional groups and nonionic functional groups. Acidic functional groups have dissociative protons and may be neutralized with bases such as amines and hydroxide ions, while basic functional groups are neutralized with acids such as organic acids and inorganic acids. may

Examples of acidic functional groups include carboxyl group (--COOH), sulfo group (--SO ₃ H), sulfate group (--OSO ₃ H), phosphonic acid group (--PO(OH) ₃ ), phosphoric acid group (--OPO ( OH) ₃ ), phosphinic acid group (--PO(OH)--), mercapto group (--SH).

Basic functional groups include primary, secondary and tertiary amino groups, ammonium groups, imino groups, and nitrogen-containing heterocyclic groups such as pyridine, pyrimidine, pyrazine, imidazole and triazole.

Nonionic functional groups include hydroxy group, ether group, thioether group, sulfinyl group (-SO-), sulfonyl group ( _-SO2- ), carbonyl group, formyl group, ester group, carbonate group, amide group, Carbamoyl group, ureido group, thioamide group, thioureido group, sulfamoyl group, cyano group, alkenyl group, alkynyl group, phosphine oxide group and phosphine sulfide group.

The polymeric dispersant may be a polymer (homopolymer) of a single monomer, or a copolymer (copolymer) of a plurality of types of monomers. Further, the polymeric dispersant may be any of random copolymers, block copolymers and graft copolymers. When the polymeric dispersant is a graft copolymer, it may be a comb-shaped graft copolymer or a star-shaped graft copolymer. Examples of polymer dispersants include acrylic resins, polyester resins, polyurethane resins, polyamide resins, polyethers, phenol resins, silicone resins, polyurea resins, amino resins, epoxy resins, polyamines such as polyethyleneimine and polyallylamine, and polyimides. It's okay.

Commercially available products can be used as the polymer dispersant, and commercial products include Ajinomoto Fine-Techno Co., Inc.'s Ajisper PB series, BYK's DISPERBYK series and BYK-series, and BASF's Efka series. etc. can be used.

[phosphite triester]
The ink composition may further contain a phosphite triester. By using a phosphite triester together with a polyfunctional (meth)acrylic compound and a polyfunctional (meth)allyl compound, the external quantum efficiency and light resistance of the pixel portion tend to be further improved.

［式（２）中、Ｘ^１～Ｘ^３は、それぞれ独立して、酸素原子又は硫黄原子を示し、Ｒ^２１～Ｒ^２３は、それぞれ独立して、一価の炭化水素基を示す。Ｒ^２１～Ｒ^２３のうちの少なくとも一つはアルキル基であることが好ましい。］

［式（３）中、Ｘ^４～Ｘ^９は、それぞれ独立して、酸素原子又は硫黄原子を示し、Ｙは二価の炭化水素基を示し、Ｒ^３１～Ｒ^３４は、それぞれ独立して、一価の炭化水素基を示す。Ｒ^３１～Ｒ^３４のうちの少なくとも一つはアルキル基であることが好ましい。］

［式（４）中、Ｘ^１０～Ｘ^１５は、それぞれ独立して、酸素原子又は硫黄原子を示し、Ｚは四価の炭化水素基を示し、Ｒ^４１及びＲ^４２は、それぞれ独立して、一価の炭化水素基を示す。Ｒ^４１及びＲ^４２のうちの少なくとも一方はアルキル基であることが好ましい。］ Examples of the phosphite triester include compounds represented by the following formula (2), compounds represented by the following formula (3), and compounds represented by the following formula (4).

[In Formula (2), X ¹ to X ³ each independently represent an oxygen atom or a sulfur atom, and R ²¹ to R ²³ each independently represent a monovalent hydrocarbon group. At least one of R ²¹ to R ²³ is preferably an alkyl group. ]

[In formula (3), X ⁴ to X ⁹ each independently represent an oxygen atom or a sulfur atom, Y represents a divalent hydrocarbon group, R ³¹ to R ³⁴ each independently Indicates a monovalent hydrocarbon group. At least one of R ³¹ to R ³⁴ is preferably an alkyl group. ]

[In formula (4), X ¹⁰ to X ¹⁵ each independently represent an oxygen atom or a sulfur atom, Z represents a tetravalent hydrocarbon group, R ⁴¹ and R ⁴² each independently Indicates a monovalent hydrocarbon group. At least one of R ⁴¹ and R ⁴² is preferably an alkyl group. ]

The number of carbon atoms in the monovalent hydrocarbon group in formulas (2) to (4) may be 1-30, or may be 1-18. Monovalent hydrocarbon groups include, for example, phenyl group, naphthyl group, tert-butylphenyl group, di-tert-butylphenyl group, octylphenyl group, nonylphenyl group, isodecylphenyl group, isodecylphenyl group, isodecyl Although it may be an aromatic hydrocarbon group such as a naphthyl group, it preferably does not have an aromatic ring. That is, the monovalent hydrocarbon group is preferably an aliphatic hydrocarbon group. The monovalent hydrocarbon group is more preferably an acyclic aliphatic hydrocarbon group, more preferably an alkyl group.

Alkyl groups may be straight or branched. The number of carbon atoms in the alkyl group is preferably 1-13, more preferably 4-10. Alkyl groups include, for example, 2-ethylhexyl, butyl, octyl, nonyl, decyl, isodecyl, dodecyl and tridecyl groups. Alkyl groups are preferably primary alkyl groups. In formulas (2) to (4), all monovalent hydrocarbon groups are preferably primary alkyl groups.

The divalent hydrocarbon group in formula (3) preferably does not have an aromatic ring structure. That is, the divalent hydrocarbon group is preferably an aliphatic hydrocarbon group. Aliphatic hydrocarbon group, some of the carbon atoms may be substituted with hetero atoms, oxygen atoms, sulfur atoms and at least one hetero atom selected from the group consisting of nitrogen atoms. good. The number of carbon atoms in the hydrocarbon group of the divalent hydrocarbon group is, for example, 1-30.

The tetravalent hydrocarbon group in formula (4) preferably does not have an aromatic ring structure. That is, the tetravalent hydrocarbon group is preferably an aliphatic hydrocarbon group. The number of carbon atoms in the tetravalent hydrocarbon group is, for example, 1-9.

From the viewpoint of further improving the external quantum efficiency, the phosphite ester compound is preferably a compound represented by Formula (4) among the above.

Specific examples of phosphite triesters include triethyl phosphite, tris(2-ethylhexyl) phosphite, tridecyl phosphite, trilauryl phosphite, tris(tridecyl) phosphite, trioleyl phosphite, tristearyl Phosphite, diphenyl mono(2-ethylhexyl) phosphite, diphenyl monodecyl phosphite, diphenyl mono(tridecyl) phosphite, trilauryltrithiophosphite, tetra(C12-C15 alkyl)-4,4'-isopropylidenediphenyl diphenyl Phosphite, 4,4'-butylidenebis(3-methyl-6-t-butylphenyl ditridecylphosphite), bis(decyl)pentaerythritol diphosphite, bis(tridecyl)pentaerythritol diphosphite, distearylpentaerythritol diphosphite and the like. Among them, triethylphosphite, tris(2-ethylhexyl)phosphite, tridecylphosphite, trilaurylphosphite, tris(tridecyl)phosphite, trilauryl, from the viewpoint of further improving the external quantum efficiency. Preferred are trithiophosphite, bis(decyl)pentaerythritol diphosphite and bis(tridecyl)pentaerythritol diphosphite, more preferred are bis(decyl)pentaerythritol diphosphite and bis(tridecyl)pentaerythritol diphosphite. The phosphite triester may be used singly or in combination.

The content of the phosphite triester is 0.01 parts by mass or more relative to the total 100 parts by mass of the components other than the organic solvent contained in the ink composition, from the viewpoint of further suppressing the decrease in the external quantum efficiency. and may be 0.1 parts by mass or more, 0.2 parts by mass or more, or 0.3 parts by mass or more. The content of the phosphite triester makes it possible to ensure a better film strength when forming the coating film, and further suppresses the bleeding of the phosphite triester to the surface of the pixel part, From the viewpoint of obtaining excellent external quantum efficiency, it is preferably 3 parts by mass or less, more preferably 2 parts by mass or less, relative to the total 100 parts by mass of the components other than the organic solvent contained in the ink composition, More preferably, it is 1 part by mass or less.

[Organic solvent]
The ink composition may further contain an organic solvent. Examples of organic solvents 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 succinic acid. diethyl, 1,4-butanediol diacetate, glyceryl triacetate and the like.

The boiling point of the organic solvent is preferably 150° C. or higher, more preferably 180° C. or higher, from the viewpoint of continuous ejection stability of the inkjet ink. Further, since the solvent must be removed from the ink composition before it is cured when forming the pixel portion, the boiling point of the organic solvent is preferably 300° C. or lower from the viewpoint of easy removal of the organic solvent.

The organic solvent preferably contains an acetate compound having a boiling point of 150°C or higher. In this case, the affinity between the luminescent nanocrystalline particles and the solvent is improved, and the luminescent nanocrystalline particles can exhibit excellent luminous properties. Specific examples of acetate compounds 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 diol. Acetate, diacetate compounds such as propylene glycol diacetate, triacetate compounds such as glycerol triacetate, and the like.

Since the ink composition of the present embodiment contains a polyfunctional (meth)acrylic compound and a polyfunctional (meth)allyl compound, the luminescent nanocrystalline particles are contained in the polyfunctional (meth)acrylic compound and the polyfunctional (meth)allyl compound. etc. can be distributed. Therefore, the ink composition need not contain solvent. In this case, the process of removing the solvent by drying is not necessary when forming the pixel portion.

The ink composition may further contain components other than the components described above as long as the effects of the present invention are not impaired.

The ink composition may further contain, for example, a polymerizable compound other than the polyfunctional (meth)acrylic compound and the polyfunctional (meth)allyl compound. Other polymerizable compounds include compounds having an ethylenically unsaturated group such as monofunctional (meth)acrylic compounds and monofunctional (meth)allyl compounds. As used herein, an ethylenically unsaturated group means a group having an ethylenically unsaturated bond (polymerizable carbon-carbon double bond). Examples of ethylenically unsaturated groups include vinyl groups, vinylene groups, vinylidene groups, (meth)acryloyl groups, and (meth)allyl groups.

The ink composition contains, for example, a component that functions as an antioxidant other than the phosphite triester compound (e.g., a phenol-based antioxidant, an amine-based antioxidant, a phosphorous-based antioxidant other than the phosphite triester compound, , a conventionally known antioxidant such as a sulfur-based antioxidant) may be further contained.

The viscosity of the ink composition described above at an ink temperature (for example, 25° C. or 40° C.) during inkjet printing may be, for example, 2 mPa·s or more, or 5 mPa·s, from the viewpoint of ejection stability during inkjet printing. or more, or 7 mPa·s or more. The viscosity of the ink composition at the ink temperature during inkjet printing may be 20 mPa·s or less, 15 mPa·s or less, or 12 mPa·s or less. The viscosity of the ink composition at the ink temperature during inkjet printing 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, and 5 to 12 mPa·s. s, 7 to 20 mPa·s, 7 to 15 mPa·s, or 7 to 12 mPa·s. As used herein, the viscosity of the ink composition is, for example, the viscosity measured by an E-type viscometer.

When the viscosity of the ink composition at the ink temperature during inkjet printing is 2 mPa s or more, the meniscus shape of the inkjet ink at the tip of the ink ejection hole of the ejection head is stabilized. control of the amount and timing of ejection) becomes easier. On the other hand, when the viscosity of the ink composition at the ink temperature during inkjet printing is 20 mPa·s or less, the inkjet ink can be smoothly ejected from the ink ejection holes.

The surface tension of the ink composition is preferably a surface tension suitable for an inkjet system, specifically preferably in the range of 20 to 40 mN/m, more preferably 25 to 35 mN/m. . By setting the surface tension within this range, it is possible to facilitate ejection control (for example, control of ejection amount and ejection timing) and to suppress the occurrence of flight deflection. The term "flight deflection" means that when the ink composition is ejected from the ink ejection holes, the landing position of the ink composition deviates from the target position by 30 μm or more. 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 the 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, contamination of the periphery of the ink ejection holes with the ink jet ink can be prevented, so that the occurrence of flight deflection can be suppressed. That is, the ink composition is not accurately deposited on the pixel portion forming region where the ink composition should be deposited, resulting in an insufficiently filled pixel portion, or the pixel portion forming region (or pixel portion) adjacent to the pixel portion forming region where the ink composition should be deposited. The ink composition does not land on the surface, and the color reproducibility is not deteriorated.

When the ink composition of the present embodiment is used as an ink composition for an ink jet system, it is preferably applied to a piezo jet 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 high temperatures during ejection. Therefore, the luminescent nanocrystalline particles are less likely to be degraded, and expected luminous properties can be more easily obtained in the pixel portion (light conversion layer).

Although one embodiment of the ink composition for inkjet has been described above, the ink composition for inkjet according to the embodiment described above can also be used in, for example, 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 photolithography, first, the ink composition is applied onto a substrate, and the ink composition is dried to form a coating film. The coating film thus obtained is soluble in an alkaline developer, and is patterned by being treated with an alkaline developer. At this time, the alkali developer is mostly an aqueous solution from the viewpoint of ease of disposal of the waste liquid of the developer, and therefore the coating film of the ink composition is treated with an aqueous solution. On the other hand, in the case of an ink composition using luminescent nanocrystalline particles (quantum dots, etc.), the luminescent nanocrystalline particles are unstable against water, and luminescence (for example, fluorescence) is impaired by moisture. For this reason, in the present embodiment, the ink jet method is preferable because it does not require treatment with an alkaline developer (aqueous solution).

In addition, even when the coating film of the ink composition is not treated with an alkaline developer, if the ink composition is alkali-soluble, the coating film of the ink composition easily absorbs moisture in the atmosphere. Luminescent properties (for example, fluorescence) of luminescent nanocrystalline particles (quantum dots, etc.) deteriorate over time. From this point of view, 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 polyfunctional (meth)acrylic compound and a polyfunctional (meth)allyl compound as the polyfunctional (meth)acrylic compound and the polyfunctional (meth)allyl compound. can. The coating film of the ink composition being alkali-insoluble means that the amount of dissolution of the coating film of the ink composition in a 1% by mass potassium hydroxide aqueous solution at 25° C. is, based on the total mass of the coating film of the ink composition, It means that it is 30% by mass or less. The amount of the ink composition dissolved in the coating film is preferably 10% by mass or less, and more preferably 3% by mass or less. It should be noted that the fact that the ink composition is an ink composition capable of forming an alkali-insoluble coating film means that the thickness obtained by applying the ink composition on a substrate and then drying it under the conditions of 80° C. for 3 minutes It can be confirmed by measuring the amount of dissolution of the coating film 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. As an example, a method for producing an ink composition containing light-scattering particles and a polymer dispersant will be described below.

A 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 second step of mixing the crystal grains. In this method, the dispersion of light-scattering particles may further contain a polyfunctional (meth)acrylic compound and/or a polyfunctional (meth)allyl compound, and in the second step, the polyfunctional (meth)acrylic compound and / Or a polyfunctional (meth)allyl compound may be further mixed. The polyfunctional (meth)acrylic compound and the polyfunctional (meth)allyl compound may be added simultaneously or in different steps. According to the above method, the light-scattering particles can be sufficiently dispersed. Therefore, it is possible to improve the optical properties (for example, external quantum efficiency) of the pixel portion, and easily obtain an ink composition having excellent ejection stability.

In the step of preparing a dispersion of light-scattering particles, light-scattering particles, a polymer dispersant, and optionally a polyfunctional (meth)acrylic compound and/or a polyfunctional (meth)allyl compound are mixed, A dispersion of light-scattering particles may be prepared by performing a dispersion treatment. Mixing and dispersing treatments may be carried out using dispersing equipment such as bead mills, paint conditioners, planetary stirrers, jet mills and the like. It is preferable to use a bead mill or a paint conditioner from the viewpoint of improving the dispersibility of the light-scattering particles and facilitating adjustment of the average particle size of the light-scattering particles to a desired range. By mixing the light-scattering particles and the polymer dispersing agent before mixing the light-emitting nanocrystalline particles and the light-scattering particles, the light-scattering particles can be more fully dispersed. Therefore, excellent ejection stability and excellent external quantum efficiency can be obtained more easily.

In the method for producing an ink composition, before the second step, a luminescent nanocrystal containing luminescent nanocrystal particles and a polyfunctional (meth)acrylic compound and/or a polyfunctional (meth)allyl compound It may further comprise the step of providing a dispersion of particles. In this case, in the second step, a dispersion of light-scattering particles and a dispersion of luminescent nanocrystalline particles are mixed. In the step of preparing a dispersion of luminescent nanocrystalline particles, the luminescent nanocrystalline particles are mixed with a polyfunctional (meth)acrylic compound and/or a polyfunctional (meth)allyl compound and subjected to dispersion treatment. Luminescent nanocrystalline particle dispersions may be prepared. Luminescent nanocrystalline particles may be luminescent nanocrystalline particles having organic ligands on their surfaces. That is, the luminescent nanocrystalline particle dispersion may further contain an organic ligand. Mixing and dispersing treatments may be carried out using dispersing equipment such as bead mills, paint conditioners, planetary stirrers, jet mills and the like. It is preferable to use a bead mill, a paint conditioner, or a jet mill from the viewpoint of improving the dispersibility of the luminescent nanocrystalline particles and facilitating adjustment of the average particle size of the luminescent nanocrystalline particles to a desired range. According to this method, the luminescent nanocrystalline particles can be sufficiently dispersed. Therefore, it is possible to improve the optical properties (for example, external quantum efficiency) of the pixel portion, and easily obtain an ink composition having excellent ejection stability.

In this production method, other components (phosphite triester, etc.) other than the components described above may be further used. In this case, the other component may be contained in the luminescent nanocrystalline particle dispersion or the light-scattering particle dispersion. Other ingredients may also be mixed with the composition obtained by mixing the luminescent nanocrystalline particle dispersion and the light scattering particle dispersion.

<Ink composition set>
An ink composition set of one embodiment includes the ink composition of the embodiment described above. The ink composition set may include an ink composition that does not contain luminescent nanocrystalline particles (non-luminescent ink composition) in addition to the ink composition (luminescent ink composition) of the embodiment described above. A non-luminescent ink composition is, for example, a curable ink composition. The non-luminescent ink composition may be a conventionally known ink composition, and has the same composition as the ink composition (luminescent ink composition) of the above-described embodiment except that it does not contain luminescent nanocrystalline particles. may be

Since the non-luminous ink composition does not contain luminous nanocrystal particles, light is allowed to enter the pixel portion formed by the non-luminous ink composition (the pixel portion containing the cured product of the non-luminous ink composition). In this case, the light emitted from the pixel portion has substantially the same wavelength as the incident light. Therefore, the non-luminous ink composition is preferably used to form a pixel portion having the same color as the light from the 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 with the non-luminescent ink composition can be a blue pixel portion.

The non-luminescent ink composition preferably contains light scattering particles. When the non-luminous ink composition contains light-scattering particles, the pixel portion formed from the non-luminous ink composition can scatter light incident on the pixel portion, thereby It is possible to reduce the light intensity difference in the viewing angle of the light emitted from the portion.

<Light conversion layer and color filter>
Hereinafter, details of the light conversion layer and the color filter obtained using the ink composition set of the embodiment described above will be described with reference to the drawings. In the following description, the same reference numerals are used for the same or corresponding elements, and overlapping descriptions are omitted.

FIG. 1 is a schematic cross-sectional view of a color filter of one embodiment. As shown in FIG. 1 , the color filter 100 includes a base material 40 and a light conversion layer 30 provided on the base material 40 . The light conversion layer 30 includes a plurality of pixel portions 10 and a light shielding portion 20 .

The light conversion layer 30 has, as pixel units 10, a first pixel unit 10a, a second pixel unit 10b, and a third pixel unit 10c. The first pixel section 10a, the second pixel section 10b, and the third pixel section 10c are arranged in a grid so as to repeat 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 third pixel portion 10c. is provided between the first pixel portion 10c and the first pixel portion 10a. In other words, these adjacent pixel portions are separated by the light shielding portion 20 .

The first pixel portion 10a and the second pixel portion 10b are luminescent pixel portions (luminescent pixel portions) each containing a cured product of the ink composition of the embodiment described above. The cured product shown in FIG. 1 contains luminescent nanocrystalline particles, a curing component, and light scattering particles. In other words, the first pixel portion 10a includes the first curing component 13a, and the first luminescent nanocrystalline 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 curing component 13b, and second luminescent nanocrystalline particles 11b and second light scattering particles 12b dispersed in the second curing component 13b, respectively. including. A curable component is a component obtained by polymerization of a polyfunctional (meth)acrylic compound and a polyfunctional (meth)allyl compound. The curing component may contain a polymer containing a structural unit derived from a polyfunctional (meth)acrylic compound and a polymer containing a structural unit derived from a polyfunctional (meth)allyl compound. A polymer containing a structural unit derived from a compound and a structural unit derived from a polyfunctional (meth)allyl compound may be included. The curing component may include organic components (organic ligands, polymer dispersants, unreacted polymerizable compounds, etc.) contained in the ink composition, in addition to the above polymers. In the first pixel portion 10a and the second pixel portion 10b, the first curing component 13a and the second curing component 13b may be the same or different, and may be the first light scattering particles 12a. It may be the same as or different from the second light scattering particles 12b.

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

The content of the luminescent nanocrystalline particles in the luminescent pixel portion is based on the total mass of the cured luminescent ink composition, from the viewpoint of obtaining an excellent effect of improving the external quantum efficiency and obtaining excellent emission intensity. It is preferably 5% by mass or more, and may be 10% by mass or more, 15% by mass or more, 20% by mass or more, or 30% by mass or more. The content of the luminescent nanocrystalline particles is preferably 80% by mass or less based on the total mass of the cured luminescent ink composition, from the viewpoint of obtaining excellent reliability of the pixel portion and excellent emission intensity. and may be 75% by mass or less, 70% by mass or less, or 60% by mass or less.

The content of the light-scattering particles in the luminescent pixel portion is 0.1% by mass or more and 1% by mass, based on the total mass of the cured luminescent ink composition, from the viewpoint of improving the external quantum efficiency. or more, or 3% by mass or more. The content of the light-scattering particles is 60% by mass or less, 50% by mass or less, based on the total mass of the cured luminescent ink composition, from the viewpoint of improving the external quantum efficiency and the reliability of the pixel portion. % by mass or less, 40% by mass or less, 30% by mass or less, 25% by mass or less, 20% by mass or less, or 15% by mass or less.

The third pixel portion 10c is a non-luminous pixel portion (non-luminous pixel portion) containing a cured product of the non-luminous ink composition described above. The cured product does not contain luminescent nanocrystalline particles, but contains light-scattering particles and a curing component. That is, the third pixel portion 10c includes a third curing component 13c and third light scattering particles 12c dispersed in the third curing component 13c. The third curing component 13c is, for example, a component obtained by polymerizing a polymerizable compound, and includes a polymer of the polymerizable compound. 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 section 10c has, for example, a transmittance of 30% or more for light with a wavelength in the range of 420 to 480 nm. Therefore, the third pixel section 10c functions as a blue pixel section when using a light source that emits light with a wavelength in the range of 420 to 480 nm. Note that the transmittance of the third pixel section 10c can be measured with a microspectroscope.

The content of the light-scattering particles in the non-luminous pixel portion is 1% by mass based on the total mass of the cured non-luminous ink composition, from the viewpoint of further reducing the difference in light intensity at viewing angles. or more, may be 5% by mass or more, or may be 10% by mass or more. From the viewpoint of further reducing light reflection, the content of the light-scattering particles may be 80% by mass or less, and 75% by mass or less, based on the total mass of the cured product of the non-luminous ink composition. It may be 70% by mass or less.

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, 1 μm or more, 2 μm or more, or 3 μm or more. 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. 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 for the purpose of preventing leakage of light from the light source. The material constituting the light shielding part 20 is not particularly limited, and in addition to metals such as chromium, curing of a resin composition in which light shielding particles such as carbon fine particles, metal oxides, inorganic pigments, organic pigments, etc. are contained in a binder polymer. objects, etc. 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, etc., photosensitive resin, O/W An emulsion-type resin composition (for example, an emulsified reactive silicone) can be used. The thickness of the light shielding portion 20 may be, for example, 0.5 μm or more and 10 μm or less.

The base material 40 is a transparent base material having optical transparency. A flexible base material or the like can be used. Among these, it is preferable to use a glass substrate made of alkali-free glass that does not contain an alkali component. Specifically, "7059 glass", "1737 glass", "Eagle 200" and "Eagle XG" manufactured by Corning, "AN100" manufactured by Asahi Glass Co., Ltd., "OA-10G" manufactured by Nippon Electric Glass Co., Ltd. and " OA-11” is preferred. These materials have 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 using a light source that emits light with a wavelength in the range of 420 to 480 nm.

The color filter 100 can be manufactured, for example, by forming the light-shielding portions 20 in a pattern on the substrate 40 and then forming the pixel portions 10 in the pixel-forming regions partitioned by the light-shielding portions 20 on the substrate 40. . The pixel portion 10 includes a step of selectively applying an ink composition (inkjet ink) to a pixel portion forming region on the base material 40 by an inkjet method, a step of drying the ink composition to remove the organic solvent, and a step of drying the ink composition. and a step of irradiating the ink composition of (1) with an active energy ray (eg, ultraviolet rays) to cure the ink composition to obtain a luminescent pixel portion. A luminescent pixel portion can be obtained by using the luminescent ink composition described above as the ink composition, and a non-luminescent pixel portion can be obtained by using a non-luminescent ink composition.

The method of forming the light shielding portion 20 is to form a thin film of a metal such as chromium or a thin film of a resin composition containing light shielding particles in a region that serves as a boundary between a plurality of pixel portions on one side of the substrate 40. and a method of patterning this thin film. The metal thin film can be formed, for example, by a sputtering method, a vacuum deposition method, or the like, and the thin film of the resin composition containing light-shielding particles can be formed, for example, by a method such as coating or printing. As a method for patterning, a photolithography method or the like can be used.

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

In drying the ink composition, at least part of the organic solvent should be removed, and preferably all of the organic solvent is removed. The method for drying the ink composition is preferably drying under reduced pressure (reduced pressure drying). From the viewpoint of controlling the composition of the ink composition, the drying under reduced pressure is usually carried out under a pressure of 1.0 to 500 Pa at 20 to 30° C. for 3 to 30 minutes.

For curing the ink composition, for example, a mercury lamp, a metal halide lamp, a xenon lamp, an LED, or the like may be used. The wavelength of the irradiated light may be, for example, 200 nm or more and 440 nm or less. The exposure dose may be, for example, 10 mJ/cm ² or more and 4000 mJ/cm ² or less.

Although one embodiment of the color filter, the light conversion layer, and the manufacturing method thereof has been described above, the present invention is not limited to the above embodiment.

For example, the light conversion layer may be a pixel portion ( blue pixel portion). In addition, the light conversion layer may include pixel portions (e.g., yellow pixel portions) containing a cured product of a luminescent ink composition containing nanocrystalline particles that emit light of a color other than red, green, and blue. good. In these cases, each of the luminescent nanocrystalline particles contained in each pixel portion of the light conversion layer preferably has a maximum absorption wavelength in the same wavelength range.

Moreover, at least part of the pixel portion of the light conversion layer may contain a cured product of a composition containing a pigment other than the luminescent nanocrystalline particles.

Further, the color filter may include an ink-repellent layer made of an ink-repellent material and having a narrower width than the light-shielding portion on the pattern of the light-shielding portion. Further, instead of providing an ink-repellent layer, a photocatalyst-containing layer as a variable wettability layer is formed in a solid manner in a region including a pixel portion forming region, and then light is applied to the photocatalyst-containing layer through a photomask. By irradiating and exposing, the ink affinity of the pixel portion forming region may be selectively increased. Examples of photocatalysts include titanium oxide and zinc oxide.

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

Also, the color filter may have 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 eluting into the liquid crystal layer. It is provided. Materials used for known color filter protective layers can be used for the protective layer.

Further, in manufacturing the color filter and the light conversion layer, the pixel portion may be formed by the photolithography method instead of the inkjet method. In this case, first, the ink composition is applied to the base material in layers to form an ink composition layer. Next, after the ink composition layer is exposed in a pattern, it is 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 the material for the ink composition. However, the inkjet method is superior to the photolithography method from the viewpoint of efficiency in using materials. This is because the photolithographic method, in principle, removes approximately two-thirds or more of the material, thus wasting the material. Therefore, in the present embodiment, it is preferable to use inkjet ink and form the pixel portion by an inkjet method.

In addition to the luminescent nanocrystalline particles described above, the pixel portion of the light conversion layer of the present embodiment may further contain a pigment having substantially the same color as the luminescent color of the luminescent nanocrystalline particles. In order to contain the pigment in the pixel portion, the ink composition may contain the pigment.

Further, one or two 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 are The pixel portion may contain a coloring material without containing crystal grains. As the coloring material that can be used here, known coloring materials can be used. For example, the coloring material used in the red pixel portion (R) includes a diketopyrrolopyrrole pigment and/or an anionic red organic dye. mentioned. The coloring material used in the green pixel portion (G) includes at least one selected from the group consisting of halogenated copper phthalocyanine pigments, phthalocyanine green dyes, and mixtures of phthalocyanine blue dyes and azo yellow organic dyes. Coloring materials used in the blue pixel portion (B) include ε-type copper phthalocyanine pigments and/or cationic blue organic dyes. When these colorants are contained in the light conversion layer, the amount used is 1 to 5 masses based on the total mass of the pixel portion (cured product of the ink composition) from the viewpoint of preventing a decrease in transmittance. %.

EXAMPLES The present invention will be specifically described below with reference to examples. However, the present invention is not limited only to the following examples. All the materials used in the examples were obtained by introducing argon gas to replace dissolved oxygen with argon gas. Titanium oxide was used after being 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 materials used in the examples were dehydrated with molecular sieves 3A for 48 hours or more before mixing.

<Preparation of photopolymerizable compound>
The following compounds were prepared as polyfunctional (meth)acrylic monomers and polyfunctional (meth)allyl monomers.
[Polyfunctional (meth)acrylic monomer]
· HDDA (1,6-hexanediol diacrylate, manufactured by Osaka Organic Chemical Industry Co., Ltd., trade name: Viscoat #230)
[Polyfunctional (meth)allyl monomer]
・DAP (diallyl phthalate, manufactured by Osaka Soda Co., Ltd., product name: Daiso Dap Monomer)

<Preparation of Green-Emitting InP/ZnSeS/ZnS Nanocrystalline Particle Dispersion>
[Preparation of indium laurate solution]
10 g of 1-octadecene (ODE), 146 mg (0.5 mmol) of indium acetate and 300 mg (1.5 mmol) of lauric acid were added to the reaction flask to obtain a mixture. A clear solution (indium laurate solution) was obtained by heating the mixture at 140° C. for 2 hours under vacuum. This solution was kept in the glove box at room temperature until needed. In addition, since indium laurate has low solubility at room temperature and tends to precipitate, when using an indium laurate solution, the precipitated indium laurate in the solution (ODE mixture) should be heated to about 90° C. to obtain a transparent solution. After forming the solution, the desired amount was weighed out.

[Preparation of core (InP core) of green-emitting nanocrystalline particles]
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 at 250° C. for 20 minutes under vacuum. The reaction temperature (temperature of the mixture) was then raised 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 rapidly introduced into the reaction flask and the reaction temperature was maintained at 260°C. After 5 minutes, the reaction was stopped by removing the heater and the resulting reaction solution was cooled to room temperature. 8 ml of toluene and 20 ml of ethanol were then added to the reaction solution in the glove box. Subsequently, centrifugation was performed to precipitate the InP nanocrystalline particles, and the supernatant was decanted to obtain InP nanocrystalline particles. The resulting InP nanocrystal particles were then dispersed in hexane. As a result, a dispersion containing 5% by mass of InP nanocrystal particles (hexane dispersion) was obtained.

The hexane dispersion of the InP nanocrystal particles obtained above and the indium laurate solution were charged into a reaction flask to obtain a mixture. The amounts of the hexane dispersion of InP nanocrystal particles and the indium laurate solution were adjusted to 0.5 g (25 mg of InP nanocrystal particles) and 5 g (178 mg of indium laurate), respectively. After allowing the mixture to stand at room temperature under vacuum for 10 minutes, the inside of the flask was returned to normal pressure with nitrogen gas, the temperature of the mixture was raised to 230°C, and the temperature was maintained for 2 hours to remove hexane from the inside of the flask. . Next, the temperature inside the flask was raised to 250°C, and a mixture of 3 g of 1-octadecene (ODE) and 0.03 g (0.125 mmol) of tris(trimethylsilyl)phosphine was rapidly introduced into the reaction flask, and the reaction temperature was raised to 230°C. maintained at After 5 minutes, the reaction was stopped by removing the heater and the resulting reaction solution was cooled to room temperature. Then, 8 ml of toluene and 20 ml of ethanol were added to the reaction solution in the glove box. Subsequently, centrifugation is performed to precipitate the InP nanocrystalline particles (InP cores), which are the cores of the green-emitting InP/ZnSeS/ZnS nanocrystalline particles. got Next, the obtained InP nanocrystalline particles (InP cores) were dispersed in hexane to obtain a dispersion (hexane dispersion) containing 5% by mass of InP nanocrystalline particles (InP cores).

[Formation of green-emitting nanocrystalline particle shell (ZnSeS/ZnS shell)]
After adding 2.5 g of the hexane dispersion of the InP nanocrystalline particles (InP cores) 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. and held for 2 hours. Then, 14 mg of diethylzinc dissolved in 1 ml of ODE, 8 mg of bis(trimethylsilyl)selenide and 7 mg of hexamethyldisilathiane (ZnSeS precursor solution) are added dropwise to this reaction mixture, and the temperature is raised to 200° C. and maintained for 10 minutes. This formed a ZnSeS shell with a thickness of 0.5 monolayer.

The temperature was then raised to 140° C. and held for 30 minutes. Next, a ZnS precursor solution obtained by dissolving 69 mg of diethyl zinc and 66 mg of hexamethyldisilathiane in 2 ml of ODE was added dropwise to this reaction mixture, and the temperature was raised to 200° C. and maintained for 30 minutes to obtain A ZnS shell with a thickness of 2 monolayers was formed. Ten minutes after the addition of the ZnS precursor solution, the reaction was stopped by removing the heater. The reaction mixture was then cooled to room temperature and the resulting white precipitate was removed by centrifugation to yield a transparent nanocrystalline particle dispersion (InP/ZnSeS /ODE dispersion of ZnS nanocrystalline particles) was obtained.

[Synthesis of organic ligands for InP/ZnSeS/ZnS nanocrystalline particles]
(Synthesis of organic ligand)
After introducing polyethylene glycol |average Mn400| (manufactured by Sigma-Aldrich) into the flask, while stirring in a nitrogen gas environment, polyethylene glycol |average Mn400| made) was added. The internal temperature of the flask was raised to 80° C. and stirred for 8 hours to obtain an organic ligand represented by the following formula (A) as a pale yellow viscous oil.

[Preparation of Green-Emitting InP/ZnSeS/ZnS Nanocrystalline Particle Dispersion by Ligand Exchange]
30 mg of the above organic ligand was added to 1 ml of the ODE dispersion of InP/ZnSeS/ZnS nanocrystalline particles obtained above. Ligand exchange was then performed by heating at 90° C. for 5 hours. Aggregation of nanocrystalline particles was observed as the ligand exchange progressed. After completion of ligand exchange, the supernatant was decanted to obtain nanocrystalline particles. Then, 3 ml of ethanol was added to the resulting nanocrystalline particles, and ultrasonically treated to redisperse them. 10 ml of n-hexane was added to 3 ml of the obtained ethanol dispersion of nanocrystalline particles. Subsequently, after centrifugation to precipitate nanocrystalline particles, the supernatant was decanted and dried under vacuum to obtain nanocrystalline particles (InP/ZnSeS/ZnS nanocrystalline particles modified with the above organic ligands). The content of organic ligands in the total amount of nanocrystalline particles modified with organic ligands was 35% by mass. The obtained nanocrystalline particles (InP/ZnSeS/ZnS nanocrystalline particles modified with the above organic ligands) are dispersed in HDDA so that the content in the dispersion is 50% by mass, thereby emitting green light. A dispersion of organic nanocrystalline particles (QD dispersion) was obtained.

<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: Ajisper PB-821, manufactured by Ajinomoto Fine-Techno Co., Ltd.) and 26.0 g of HDDA are mixed, then zirconia beads (diameter: 1.25 mm) are added to the resulting mixture, and a paint conditioner is used. The mixture was subjected to dispersion treatment by shaking for 2 hours, and the zirconia beads were removed with a polyester mesh filter to obtain a light-scattering particle dispersion (titanium oxide content: 55% by mass).

<Example 1>
[Preparation of green ink composition (inkjet ink)]
<Example 1>
0.7 g of a luminescent nanocrystalline particle dispersion, 0.062 g of a light scattering particle dispersion, and a photopolymerization initiator (phenyl (2,4,6-trimethylbenzoyl-diphenyl-phosphine oxide (IGM Resin Co.) 0.005 g of Omnirad TPO), 0.133 g of HDDA, and 0.1 g of DAP were uniformly mixed in a container filled with argon gas. Further, argon gas was introduced into the container containing the obtained filtrate, and the inside of the container was saturated with argon gas.Then, the pressure was reduced to remove the argon gas, thereby 1. The total content of luminescent nanocrystalline particles, organic ligands, photopolymerizable compounds (HDDA and DAP), and light-scattering particles is 98.5 weight based on the total weight of the inkjet ink. The total content of luminescent nanocrystalline particles and organic ligands was 100 parts by mass of the total content of luminescent nanocrystalline particles, organic ligands, photopolymerizable compounds (HDDA and DAP), and light-scattering particles. was 35 parts by mass.

<Example 2>
In addition to a luminescent nanocrystalline particle dispersion, a light scattering particle dispersion, a photopolymerization initiator, HDDA and DAP, bis(decyl) pentaerythritol diphosphite (manufactured by Johoku Chemical Industry Co., Ltd., Trade name: JPE-10), and the blending amount of these, the luminescent nanocrystalline particles and organic ligands in the ink composition, the photopolymerizable compound (polyfunctional (meth)acrylic compound and polyfunctional ( Meta) allyl compound), photopolymerization initiator, light scattering particles, polymer dispersant, and phosphite triester content were adjusted to the values shown in Table 1 (unit: parts by mass) The inkjet ink of Example 2 was obtained in the same manner as in Example 1.

<Comparative Example 1>
The amounts of the luminescent nanocrystalline particle dispersion, the light scattering particle dispersion, the photopolymerization initiator, HDDA and DAP are adjusted according to the amount of the luminescent nanocrystalline particles, the organic ligand, and the photopolymerizable compound (polyfunctional ( The contents of the meth)acrylic compound and polyfunctional (meth)allyl compound), photopolymerization initiator, light-scattering particles, and polymer dispersant are adjusted to the values shown in Table 1 (unit: parts by mass). An inkjet ink of Comparative Example 1 was obtained in the same manner as in Example 1 except for the above.

<Evaluation of external quantum efficiency (EQE)>
[Preparation of sample for external quantum efficiency evaluation]
The ink composition was applied on a glass substrate in the atmosphere using a spin coater so as to have a film thickness of 10 μm. Under a nitrogen atmosphere, the coating film is cured by irradiating UV light with a UV irradiation device using an LED lamp having a main wavelength of 395 nm so that the integrated light amount becomes 1500 mJ/cm ² , and a cured product of the ink composition is deposited on the glass substrate. A layer (light conversion layer) was formed. Thus, a sample for external quantum efficiency evaluation was obtained.

[Measurement of external quantum efficiency]
A blue LED (peak emission wavelength: 450 nm) manufactured by CCS Co., Ltd. was used as a surface emitting light source. As a measurement device, an integrating sphere was connected to a radiation 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 by lighting the blue LED and the illuminance at each wavelength were measured.

The external quantum efficiency was obtained as follows from the spectrum and illuminance measured by the above measuring device. 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, if this value is large, it indicates that the light conversion layer is excellent in light emission characteristics, which is an important evaluation index.
EQE (%) = P1 (Green)/E (Blue) x 100

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

<Evaluation of light resistance (EQE maintenance rate)>
[Preparation of sample for light resistance evaluation]
Each ink composition was applied on a glass substrate in the atmosphere using a spin coater to a thickness of 10 μm. After coating, another glass substrate is placed, and UV is irradiated from above the glass substrate with a UV irradiation device using an LED lamp with a main wavelength of 395 nm so that the integrated light amount becomes 1500 mJ / cm ² to cure the glass substrate. A layer (light conversion layer) composed of a cured product of the ink composition was formed thereon. Thus, a sample for light resistance evaluation was obtained.

[Evaluation of light resistance]
After measuring the initial EQE of the sample for light resistance evaluation prepared above with the above measuring device, the sample temperature was kept at 25-30 ° C., and the illuminance was 100 mW / cm ² , with an LED lamp with a dominant wavelength of 450 nm. irradiated. After two weeks of irradiation, the EQE was measured again, and the EQE maintenance rate was calculated by the following formula.
EQE maintenance rate (%) = EQE after 2 weeks of irradiation/initial EQE x 100

DESCRIPTION OF SYMBOLS 10... Pixel part 10a... 1st pixel part 10b... 2nd pixel part 10c... 3rd pixel part 11a... 1st luminescent nanocrystal particle 11b... 2nd luminescent nanocrystal particle , 12a... First light-scattering particles, 12b... Second light-scattering particles, 12c... Third light-scattering particles, 20... Light shielding part, 30... Light conversion layer, 40... Base material, 100... Color filter.

Claims (16)

A curable ink composition comprising luminescent nanocrystalline particles, a polyfunctional (meth)acrylic compound, a polyfunctional (meth)allyl compound , and light scattering particles . The curable ink composition according to claim 1, wherein the polyfunctional (meth)allyl compound has a benzene ring. 3. The curable ink composition according to claim 1, wherein the polyfunctional (meth)allyl compound is a bifunctional or trifunctional (meth)allyl compound. The curable ink composition according to any one of claims 1 to 3, wherein the polyfunctional (meth)allyl compound has a (meth)allyloxy group. The curable ink composition according to any one of claims 1 to 4, wherein the polyfunctional (meth)allyl compound has a molecular weight of 100 to 300. The curable ink composition according to any one of claims 1 to 5, wherein the polyfunctional (meth)allyl compound is a compound represented by the following formula (I).
[In formula (I), n represents 2 or 3, and multiple R ^1s each independently represent a hydrogen atom or a methyl group. ] The curable ink composition according to any one of claims 1 to 6, wherein the polyfunctional (meth)acrylic compound is a bifunctional or trifunctional (meth)acrylic compound. The curable ink composition according to any one of claims 1 to 7, wherein the polyfunctional (meth)acrylic compound has a molecular weight of 50 to 700. The curable ink composition according to any one of claims 1 to 8, wherein the polyfunctional (meth)acrylic compound is (poly)alkylene glycol di(meth)acrylate. The curable ink composition according to any one of claims 1 to 9 , further comprising a phosphite triester. The curable ink composition according to any one of claims 1 to 10 , which is used for forming a light conversion layer. The curable ink composition according to any one of claims 1 to 10 , which is used in an inkjet system. comprising 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 portions have luminescent pixel portions containing a cured product of the curable ink composition according to any one of claims 1 to 10 . As the luminescent pixel portion,
a first luminescent pixel portion containing luminescent nanocrystalline particles that absorb light with a wavelength in the range of 420 to 480 nm and emit light with an emission peak wavelength in the range of 605 to 665 nm;
a second luminescent pixel portion containing luminescent nanocrystalline particles that absorb light with a wavelength in the range of 420 to 480 nm and emit light with an emission peak wavelength in the range of 500 to 560 nm;
14. The light conversion layer of claim 13 , comprising: 15. The light conversion layer according to claim 13 or 14 , further comprising non-emissive pixel portions containing light scattering particles. A color filter comprising the light conversion layer according to any one of claims 13-15 .

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