Color conversion components, including their light source units, displays, and lighting devices.

Abstract

One aspect of the color conversion component of the present invention is a color conversion component that converts incident light into light with a wavelength different from the incident light, and includes at least the following (A) layer and (B) layer. The (A) layer is a color conversion layer containing at least one organic light-emitting material that emits delayed fluorescence and an adhesive resin. The (B) layer is a layer with an oxygen transmittance of 1.0 cc / m²·day·atm or less.

Description

[Technical Field]

[0001] The present invention relates to a color conversion component, a light source unit including the component, a display, and a lighting device. [Previous Technology]

[0002] Multicolor conversion technology based on color conversion methods is being actively researched for application in liquid crystal displays or organic electroluminescence (EL) displays, lighting devices, etc. Color conversion refers to converting light emitted from a light source into light with a longer wavelength, such as converting blue light into green light or red light.

[0003] By sheeting a component with this color conversion function (hereinafter referred to as a color conversion component) and combining it with, for example, a blue light source, the three primary colors of blue, green, and red can be obtained from the blue light source, that is, white light can be obtained. This white light source, formed by combining a blue light source with a sheet having a color conversion function (hereinafter referred to as a color conversion sheet), can be used as a light source unit such as a backlight unit. Furthermore, by combining this light source unit with a liquid crystal driving section and a color filter, a full-color display can be manufactured. In addition, the white light source formed by combining a blue light source with a color conversion sheet can also be directly used as a white light source (lighting device) such as a light-emitting diode (LED) illumination.

[0004] As a problem of liquid crystal displays utilizing color conversion methods, improvements in color reproduction and durability can be cited. When improving color reproduction, it is effective to narrow the half-width of the emission spectra of blue, green, and red light sources, thereby increasing the color purity of each of the blue, green, and red colors. As a means of solving this problem, a technique has been proposed that uses quantum dots obtained from inorganic semiconductor microparticles as components of the color conversion composition (for example, see Patent Document 1).

[0005] Furthermore, techniques have been proposed that use luminescent materials containing organic compounds with lower concerns about toxic elements such as cadmium as components of color conversion materials instead of quantum dots. Examples of techniques using organic luminescent materials as components of color conversion materials include color conversion materials containing pyrrole methylene compounds (see, for example, Patent Documents 2 and 3). Additionally, techniques for improving durability have been proposed that improve durability by blocking oxygen (see, for example, Patent Document 4). [Prior Art Documents] [Patent Documents]

[0006] Patent Document 1: Japanese Patent Application Publication No. 2012-22028; Patent Document 2: Japanese Patent Application Publication No. 2010-61824; Patent Document 3: Japanese Patent Application Publication No. 2014-136771; Patent Document 4: International Publication No. 2017 / 057287 [Summary of the Invention]

[0007] [The problem the invention aims to solve]

[0008] Previously, the technology described in Patent Document 4 provided a color conversion component with excellent color reproduction and durability. However, in recent years, with the increase in contrast brought about by high resolution, high dynamic range (HDR), and local dimming such as 4K or 8K, the required illuminance of the light source unit of the liquid crystal display has increased, and higher durability is also required for the color conversion component. The durability of the technology described in Patent Document 4 is still insufficient.

[0009] The problem this invention aims to solve is to achieve both improved color reproduction and improved durability in color conversion components used in light source units such as backlight units, displays such as liquid crystal displays, and lighting devices such as LED lighting. In particular, the object of this invention is to provide a color conversion component that balances high color purity emission with high durability. [Means for Solving the Problem]

[0010] That is, in order to solve the aforementioned problem and achieve the objective, the color conversion component involved in the present invention is a color conversion component that converts incident light into light with a wavelength different from the incident light, characterized in that it includes at least the following (A) layer and (B) layer, wherein the (A) layer is a color conversion layer containing at least one organic light-emitting material that emits delayed fluorescence and an adhesive resin, and the (B) layer is a layer with an oxygen transmittance of 1.0 cc / m2·day·atm (cc / m2·day·atm) or less. [Effects of the Invention]

[0011] The color conversion component involved in the present invention achieves the effect of improving both color reproduction and durability by taking into account both high color purity luminescence and high durability.

Implementation Method

[0013] Hereinafter, preferred embodiments of the color conversion component, the light source unit including it, the display and the lighting device involved in the present invention will be specifically described. However, the present invention is not limited to the following embodiments and can be implemented in various ways depending on the purpose or use.

[0014] <Color Conversion Component> The color conversion component according to the embodiments of the present invention is a component that converts incident light from a light source or other light-emitting body into light with a wavelength different from that incident light. Here, "converting into light with a wavelength different from that incident light" is preferably converting the incident light into light with a wavelength longer than that incident light.

[0015] Hereinafter, emission with a peak wavelength observed in the region of 500 nm or more and less than 580 nm is called "green emission", and emission with a peak wavelength observed in the region of 580 nm or more and less than 750 nm is called "red emission".

[0016] The color conversion member according to the embodiments of the present invention is a laminated member comprising at least the following (A) layer and (B) layer. The (A) layer is a color conversion layer containing an organic light-emitting material and an adhesive resin. The organic light-emitting material includes at least one "organic light-emitting material emitting delayed fluorescence" described later. The (B) layer is a layer with an oxygen permeability of 1.0 cc / m²·day·atm or less, that is, an oxygen-barrier layer. The color conversion member may include one or more (A) layers and one or more (B) layers. Furthermore, the (A) layers and (B) layers may each comprise multiple layers. In this case, each (A) layer may be a layer with the same composition or morphology as the others, or they may be different layers; each (B) layer may be a layer with the same composition or morphology as the others, or they may be different layers.

[0017] Furthermore, the color conversion member involved in the embodiments of the present invention (hereinafter, sometimes simply referred to as the color conversion member of the present invention) can have various laminated structures as long as it includes a (A) layer as a color conversion layer and a (B) layer as an oxygen barrier layer. For example, the following three examples can be listed as representative structural examples of the color conversion member of the present invention.

[0018] FIG1 is a schematic cross-sectional view showing a first example of a color conversion member according to an embodiment of the present invention. As shown in FIG1, the first example of the color conversion member 1A includes a substrate layer 10, a (A) layer 11, and a (B) layer 12, and forms a laminate of these layers. In the structural example of the color conversion member 1A, a (A) layer 11 is laminated on the substrate layer 10, and a (B) layer 12 is laminated on the (A) layer 11.

[0019] FIG2 is a schematic cross-sectional view showing a second example of a color conversion member according to an embodiment of the present invention. As shown in FIG2, the color conversion member 1B of the second example includes a substrate layer 10, an (A) layer 11, and a plurality of (two) (B) layers 12, forming a laminate of (A) layer 11 sandwiched by the plurality of (B) layers 12. In the structural example of the color conversion member 1B, the (A) layer 11 and the (B) layer 12 are laminated in the order of (B) layer / (A) layer / (B) layer, and the laminate of (A) layer 11 and (B) layer 12 is formed on the substrate layer 10. For example, a first (B) layer 12 is laminated on the substrate layer 10, an (A) layer 11 is laminated on the (B) layer 12, and a second (B) layer 12 is laminated on the (A) layer 11.

[0020] FIG3 is a schematic cross-sectional view showing a third example of a color conversion member according to an embodiment of the present invention. As shown in FIG3, the color conversion member 1C of the third example includes a plurality of (two in this embodiment) substrate layers 10, an (A) layer 11, and a plurality of (two) (B) layers 12. In the structural example of the color conversion member 1C, a laminated body is formed in which the (A) layer 12 is sandwiched between the plurality of substrate layers 10 and the (B) layers 12. Specifically, the (A) layer 11 is sandwiched between the plurality of (B) layers 12, and the laminated body of the (A) layer 11 and the plurality of (B) layers 12 is sandwiched between the plurality of substrate layers 10. For example, as shown in FIG3, this color conversion member 1C has a laminated structure formed by depositing a second substrate layer 10 on the second (B) layer 12 in the color conversion member 1B of the second example.

[0021] Figures 1 to 3 illustrate color conversion members 1A, each comprising one (A) layer 11 as a color conversion layer and one (B) layer 12 as an oxygen barrier layer, or color conversion members 1B and 1C comprising a laminate formed by two (B) layers 12 sandwiching one (A) layer 11. However, the laminated structure of the color conversion members of the present invention is not limited to these. For example, the laminated structure of (A) layer 11 and (B) layer 12 in the color conversion members of the present invention may also be as (B) layer / (A) layer / (A) layer, (B) layer / (B) layer / (A) layer, (B) layer / (B) layer / (A) layer / (A) layer, where (A) layer 11 or (B) layer 12 is continuous in the lamination direction. Furthermore, as such a laminated structure, a structure in which (B) layer 12 is continuously covered by (A) layer 11 as a whole may also be exemplified.

[0022] Furthermore, the structure of the color conversion member is illustrative, and the specific structure of the color conversion member of the present invention is not limited to the described structure. The structure of the color conversion member to which modifications are appropriate by means of the following description is also included within the scope of the present invention.

[0023] <(A) Layer> (A-1. Organic Light-Emitting Material) In this invention, the (A) layer (e.g., (A) layer 11 shown in Figures 1 to 3) is a color conversion layer and contains at least one organic light-emitting material. Here, the light-emitting material in this invention refers to a material that emits light with a wavelength different from that light when irradiated with a certain light.

[0024] In order to achieve high-efficiency color conversion, it is preferable that the luminescent material exhibits luminescent properties with high quantum yield. Generally, known luminescent materials such as inorganic phosphors, fluorescent pigments, fluorescent dyes, and quantum dots can be listed as luminescent materials. However, in this invention, from the viewpoints of uniform dispersion, reduced usage amount, and reduced environmental impact, it is preferable to use an organic luminescent material as the luminescent material in layer (A).

[0025] Among many organic light-emitting materials, layer (A) of the present invention comprises an organic light-emitting material that emits delayed fluorescence. Here, the organic light-emitting material emitting delayed fluorescence is explained on pages 87-103 of "The Most Advanced Organic EL" (edited by Chinatsu Adachi and Hiroshi Fujimoto, published by CMC). In that document, it is explained that by making the energy levels of the singlet excited state and the triplet excited state of the light-emitting material close, reverse energy transfer from the triplet excited state with a low transition probability to the singlet excited state is usually generated efficiently, exhibiting thermally activated delayed fluorescence (TADF). Furthermore, Figure 5 in that document illustrates the generation mechanism of delayed fluorescence. The emission of delayed fluorescence can be confirmed by transition PL (Photo Luminescence) measurement.

[0026] In addition, it has been reported that by aligning the energy level of the singlet excited state of a luminescent material with that of the triplet excited state, the reverse energy transfer from the triplet excited state to the singlet excited state can be accelerated (Nature Photonics (Vol. 14, pp. 643-649 (2020))). Furthermore, research is actively underway on compounds with higher energy levels in the triplet excited state than in the singlet excited state of the luminescent material.

[0027] In this specification, an organic light-emitting material that includes an organic light-emitting material exhibiting thermally activated delayed fluorescence and that efficiently transitions from a triplet excited state to a singlet excited state to emit fluorescence is described as an "organic light-emitting material emitting delayed fluorescence". In addition, hereafter, the "organic light-emitting material emitting delayed fluorescence" is sometimes simply referred to as "delayed fluorescence material".

[0028] Typically, fluorescence emission occurs when a self-luminescent material is photoexcited and generates a singlet excited state. However, triplet excited states of luminescent materials generated through intersystem crossing are thermally deactivated at room temperature. Therefore, fluorescence is not emitted from the triplet excited state of such luminescent materials. On the other hand, as described above, in delayed-emission materials, even if a triplet excited state is generated, it quickly transitions to a singlet excited state before emitting fluorescence. Therefore, in conventional luminescent materials, triplet excited states that do not contribute to luminescence can still contribute to fluorescence. Thus, highly efficient luminescence can be obtained.

[0029] Furthermore, as will be described later, the triplet excited state of an organic light-emitting material can be a major cause of its degradation. However, delayed-emission fluorescent materials can rapidly convert the triplet excited state into a singlet excited state, and therefore are expected to exhibit excellent durability. That is, in order to exhibit high durability, the inverse intersystem crossing from the triplet excited state to the singlet excited state in the delayed-emission fluorescent material is preferably fast. For example, the rate constant of this inverse intersystem crossing is preferably 1.0 × 10² s⁻¹ or higher.

[0030] As a molecular design to bring the energy levels of the singlet excited state close to those of the triplet excited state, it is effective to bond the electron donor backbone and the electron acceptor backbone within the same molecule. This allows for the separation of the HOMO (Highest occupied molecular orbital) and LUMO (Lowest unoccupied molecular orbital) orbitals within the molecule. The electron donor backbone and the electron acceptor backbone can be directly bonded or bonded via a linker group. Preferably, the linker group is a backbone containing an aromatic hydrocarbon.

[0031] Examples of electronic donor skeletons include skeletons having amine nitrogen atoms. Preferably, these are skeletons containing diarylamines or triarylamines, skeletons containing carbazole, skeletons containing benzo[a]carbazole, skeletons containing indole[a]carbazole, skeletons containing anoxazine, and skeletons containing phenoxazine. More preferably, these are skeletons containing carbazole, skeletons containing benzo[a]carbazole, skeletons containing indole[a]carbazole, and skeletons containing anoxazine, and even more preferably, skeletons containing carbazole and skeletons containing anoxazine.

[0032] On the other hand, as an electron-accepting skeleton, skeletons that typically include electron-withdrawing substituents (i.e., electron-withdrawing groups) can be listed. An electron-withdrawing group, also called an electron-accepting group, is, in organic electronic theory, an atomic group that attracts electrons from the substituted atomic group through an inducible effect or resonance effect. Examples of electron-withdrawing groups that take a positive value according to Hammett's rule for the substituent constant (σp(para)) can be listed. The Hammett's rule for the substituent constant (σp(para)) can be cited from the revised 5th edition of the Handbook of Chemistry (II-380). Furthermore, although there are examples of phenyl groups taking a positive value, in this invention, the electron-withdrawing group does not include phenyl groups.

[0033] Examples of electron-withdrawing groups include: -F (σp: +0.20), -Cl (σp: +0.28), -Br (σp: +0.30), -I (σp: +0.30), -CO2R12 (σp: +0.45 when R12 is ethyl), -CONH2 (σp: +0.38), -COR12 (σp: +0.49 when R12 is methyl), -CF3 (σp: +0.51), -SO2R12 (σp: +0.69 when R12 is methyl), -NO2 (σp: +0.81), etc. R12 independently represents a hydrogen atom, an aromatic hydrocarbon group with 6 to 30 carbon atoms (substituted or unsubstituted), a heterocyclic group with 5 to 30 carbon atoms (substituted or unsubstituted), an alkyl group with 1 to 30 carbon atoms (substituted or unsubstituted), or a cycloalkyl group with 1 to 30 carbon atoms (substituted or unsubstituted). Specific examples of these groups can be given as examples of substituents in compounds represented by general formula (2) or general formula (3) described below.

[0034] Among the frameworks containing electron-withdrawing groups, it is preferable to have a framework containing a heteroaryl group with a partial structure formed by carbon atoms and nitrogen atoms bonded by double bonds, a framework containing a fluorinated substituent, a framework containing a cyano group, a framework containing a carbonyl group, a framework containing a monoxide or a dimonoxide, and a framework containing a phosphine oxide group. From the viewpoint of delaying the stability of the fluorescent material, it is more preferable to have a framework containing a heteroaryl group with a partial structure formed by carbon atoms and nitrogen atoms bonded by double bonds, a framework containing a fluorinated substituent, and a framework containing a cyano group.

[0035] In the skeleton containing a heteroaryl group having a partial structure in which carbon atoms and nitrogen atoms are bonded by double bonds, specifically, it is preferably a skeleton containing pyridine, pyrimidine, pyrazine, triazine, quinoline, quinoxaline, quinazoline, or benzeline. Among these, it is more preferably a skeleton containing pyrimidine, triazine, quinoxaline, or quinazoline, and even more preferably a skeleton containing triazine.

[0036] In the skeleton containing fluorinated substituents, it is more preferably a skeleton containing fluorinated aryl or fluoroalkyl groups. As a skeleton containing fluorinated aryl groups, it is more preferably a fluorinated benzene ring, and more specifically, a skeleton containing fluorobenzene, difluorobenzene, trifluorobenzene, tetrafluorobenzene, or pentafluorobenzene. As a skeleton containing fluoroalkyl groups, it is more preferably a skeleton containing a benzene ring substituted with trifluoromethyl groups, and more preferably a skeleton containing mono(trifluoromethyl)benzene or bis(trifluoromethyl)benzene.

[0037] In the cyano skeleton, it is more preferably a skeleton containing cyanobenzene, dicyanobenzene, or tricyanobenzene.

[0038] The following shows an example of a compound formed by bonding an electron donor backbone and an electron acceptor backbone as described above, but the compound is not particularly limited to these. Furthermore, the compound shown here is known from previous literature to emit delayed fluorescence.

[0039] [Chemical 1]

[0040] In addition, as a delayed fluorescence material, besides the compound formed by bonding an electron donor backbone and an electron acceptor backbone, it is also preferred to be a compound containing a partial structure represented by the following general formula (1).

[0041] [Chemical 2]

[0042] In general formula (1), B is a boron atom, N is a nitrogen atom, and C is a carbon atom. n is an integer greater than or equal to 0 and less than or equal to 2. When n is 0, the partial structure represented by general formula (1) represents a direct bond structure between B and N.

[0043] In a delayed-fluorescent material containing a partial structure represented by general formula (1), an electron-donating nitrogen atom and an electron-accepting boron atom are positioned close to each other within the molecule. This delayed-fluorescent material is a compound in which the HOMO orbital and LUMO orbital can be separated by a multiple resonance effect. By clearly separating the HOMO orbital and LUMO orbital of the delayed-fluorescent material, the energy level of the singlet excited state of the delayed-fluorescent material can be made closer to the energy level of the triplet excited state, thereby facilitating the emission of delayed fluorescence. In order to make the energy level of the singlet excited state closer to the energy level of the triplet excited state, the delayed-fluorescent material is preferably a compound containing two or more partial structures represented by general formula (1) within the molecule.

[0044] Furthermore, in delayed fluorescent materials, when their π-conjugation system expands, inverse intersystem crossover is more efficiently induced from the triplet excited state to the singlet excited state. Therefore, π-conjugation system expansion of delayed fluorescent materials is preferred. In this regard, delayed fluorescent materials are preferably compounds comprising the general formula (2) or general formula (3) below.

[0045] [Chemical 3]

[0046] In general formula (2) or general formula (3), ring Za, ring Zb and ring Zc are respectively independently formed by substituted or unsubstituted rings to form aryl rings with 6 to 30 carbons, or by substituted or unsubstituted rings to form heteroaryl rings with 6 to 30 carbons.

[0047] In general formula (2), Z1 and Z2 are independently oxygen atoms, NRa (nitrogen atoms with substituent Ra), or sulfur atoms, respectively. When Z1 is NRa, the substituent Ra can bond with ring Za or ring Zb to form a ring. When Z2 is NRa, the substituent Ra can bond with ring Za or ring Zc to form a ring. E is a boron atom, a phosphorus atom, SiRa (silicon atoms with substituent Ra), or P=O.

[0048] In general formula (3), E1 and E2 are independently BRa (boron atom with substituent Ra), PRa (phosphorus atom with substituent Ra), SiRa2 (silicon atom with two substituent Ra), P(=O)Ra2 (phosphine oxide with two substituent Ra) or P(=S)Ra2 (phosphine sulfide with two substituent Ra), S(=O) or S(=O)2. When E1 is BRa, PRa, SiRa2, P(=O)Ra2 or P(=S)Ra2, the substituent Ra can bond with ring Za or ring Zb to form a ring. When E2 is BRa, PRa, SiRa2, P(=O)Ra2 or P(=S)Ra2, the substituent Ra can bond with ring Za or ring Zc to form a ring.

[0049] The substituent Ra is independently selected from hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted heterocyclic, substituted or unsubstituted alkenyl, substituted or unsubstituted cycloalkenyl, substituted or unsubstituted alkynyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, hydroxyl, thiol, substituted or unsubstituted alkoxy, substituted or unsubstituted alkylthio, substituted or unsubstituted aryl ether, substituted or unsubstituted arylthioether, halogen, cyano, aldehyde, substituted or unsubstituted carbonyl, Substituents or unsubstituted carboxyl groups, substituted or unsubstituted oxycarbonyl groups, substituted or unsubstituted ester groups, substituted or unsubstituted aminomethyl groups, substituted or unsubstituted amide groups, sulfonyl groups, substituted or unsubstituted sulfonate groups, substituted or unsubstituted sulfonamide groups, substituted or unsubstituted amino groups, substituted or unsubstituted imino groups, nitro groups, substituted or unsubstituted silyl groups, substituted or unsubstituted siloxane groups, substituted or unsubstituted oxoboryl groups, substituted or unsubstituted phosphine oxide groups, and substituents in condensation rings and aliphatic rings formed with adjacent substituents. Furthermore, substituent Ra may be further substituted with these selected substituents.

[0050] In addition, the compound represented by the general formula (2) or the general formula (3) is preferably a compound containing two or more partial structures represented by the general formula (1) within the molecule.

[0051] In all of the aforementioned groups, hydrogen may be deuterium. This also applies to the compounds described below or parts thereof. Furthermore, in this specification, for example, the term "substituted or unsubstituted aryl group with 6 to 40 carbon atoms" also includes aryl groups with 6 to 40 carbon atoms, including those contained in substituents that have substituted the aryl group. The same applies to other substituents for which a carbon number is specified.

[0052] The term "unsubstituted" in the context of "substituted or unsubstituted" refers to the substitution of hydrogen or deuterium atoms. The same applies to the context of "substituted or unsubstituted" in the compounds or parts thereof described below.

[0053] Furthermore, among all the groups, the substituents used when substituted are alkyl, cycloalkyl, heterocyclic, alkenyl, cycloalkenyl, alkynyl, aryl, heteroaryl, hydroxyl, thiol, alkoxy, alkylthio, aryl ether, aryl thioether, halogen, cyano, aldehyde, carbonyl, carboxyl, oxycarbonyl, acetylamino, sulfonyl, sulfonate, sulfonylamino, amino, nitro, silylalkyl, siloxyalkyl, oxoboryl, or phosphine oxide. Additionally, these substituents may be further substituted by the aforementioned substituents.

[0054] The term "alkyl" refers to, for example, saturated aliphatic hydrocarbon groups such as methyl, ethyl, n-propyl, isopropyl, n-butyl, dibutyl, and tributyl, which may or may not have substituents. There are no particular limitations on the additional substituents added in the case of substitution; examples include alkyl, halogen, aryl, and heteroaryl groups, and this will also be the case in the following description. Furthermore, there is no particular limitation on the number of carbon atoms in the alkyl group; however, for ease of acquisition or cost considerations, a range of 1 to 20 is preferred, and more preferably a range of 1 to 8.

[0055] The term cycloalkyl refers to, for example, saturated alicyclic hydrocarbon groups such as cyclopropyl, cyclohexyl, norbornyl, and adamantyl, which may or may not have substituents. The number of carbon atoms in the alkyl moiety is not particularly limited, but is preferably in the range of 3 to 20.

[0056] The term "heterocyclic group" refers to an aliphatic ring, such as a pyran ring, piperidine ring, or cyclic amide, which has atoms other than carbon atoms within the ring. It may or may not have substituents. The number of carbon atoms in the heterocyclic group is not particularly limited, but is preferably in the range of 2 or more and 20 or less.

[0057] The term alkenyl refers to, for example, unsaturated aliphatic hydrocarbon groups containing double bonds such as vinyl, allyl, and butadienyl, which may or may not have substituents. There is no particular limitation on the number of carbon atoms in the alkenyl group, but it is preferably in the range of 2 to 20.

[0058] The term "cycloalkenyl" refers to, for example, unsaturated alicyclic hydrocarbon groups containing a double bond, such as cyclopentenyl, cyclopentadienyl, and cyclohexenyl. These groups may or may not have substituents. The number of carbon atoms in the cycloalkenyl group is not particularly limited, but is preferably in the range of 3 to 20.

[0059] The term alkynyl group refers to, for example, an unsaturated aliphatic hydrocarbon group containing a triple bond, such as ethynyl group. It may or may not have substituents. There is no particular limitation on the number of carbon atoms in the alkynyl group, but it is preferably in the range of 2 to 20.

[0060] The term alkoxy refers to a functional group such as methoxy, ethoxy, or propoxy that has an aliphatic hydrocarbon group bonded to it via an ether bond. This aliphatic hydrocarbon group may or may not have substituents. There is no particular limitation on the number of carbon atoms in the alkoxy group, but it is preferably in the range of 1 to 20.

[0061] An alkathioyl group refers to a group in which the oxygen atom of the ether bond of an alkoxy group is replaced by a sulfur atom. The hydrocarbon group of an alkathioyl group may or may not have substituents. There is no particular limitation on the number of carbon atoms in the alkathioyl group, but it is preferably in the range of 1 to 20.

[0062] The term "aryl ether group" refers to a functional group, such as a phenoxy group, to which an aromatic hydrocarbon group is bonded via an ether bond. The aromatic hydrocarbon group may or may not have substituents. There is no particular limitation on the number of carbon atoms in the aryl ether group, but it is preferably in the range of 6 to 40.

[0063] The term "aryl sulfide group" refers to an aryl ether group in which the oxygen atom of the ether bond is replaced by a sulfur atom. The aromatic hydrocarbon group in the aryl sulfide group may or may not have substituents. There is no particular limitation on the number of carbon atoms in the aryl sulfide group, but it is preferably in the range of 6 to 40.

[0064] The term aryl refers to aromatic hydrocarbon groups such as phenyl, biphenyl, terphenyl, naphthyl, fluorenyl, benzo[fluorenyl], dibenzo[fluorenyl], phenanthryl, anthracene, benzo[phenanthryl], benzo[anthryl], 1,2-benzo[phenanthryl], pyrene, fluoranthenyl group, triphenylenyl group, benzo[anthryl], dibenzo[anthryl], peryl, and helicenyl group. Among these, phenyl, biphenyl, terphenyl, naphthyl, fluorenyl, phenanthryl, anthracene, pyrene, fluoranthenyl, and triphenyl are preferred. The aryl group may or may not have substituents. The number of carbon atoms in the aryl group is not particularly limited, but is preferably in the range of 6 to 40, and more preferably in the range of 6 to 30.

[0065] Furthermore, the aryl group is preferably phenyl, biphenyl, terphenyl, naphthyl, fluorenyl, phenanthryl, or anthracene, and more preferably phenyl, biphenyl, terphenyl, or naphthyl. Even more preferably phenyl, biphenyl, or terphenyl, and most preferably phenyl.

[0066] In cases where each substituent is further substituted with an aryl group, the aryl group is preferably phenyl, biphenyl, terphenyl, naphthyl, fluorenyl, phenanthryl, or anthracene, more preferably phenyl, biphenyl, terphenyl, or naphthyl. Phenyl is particularly preferred.

[0067] The term "heteroaryl" refers to, for example, pyridyl, furanyl, thiophene, quinolinyl, isoquinolinyl, pyrazinyl, pyrimidinyl, pyridazinyl, triazinyl, naphridinyl, cinnolinyl, phthalazinyl, quinoxolinyl, quinazolinyl, benzofuranyl, benzothiophene, indolyl, dibenzofuranyl, dibenzothiophene, carbazoyl, benzocarbazoyl, carbolinyl group, indolocarbazoyl, benzofuranocarbazoyl, benzothiophenocarbazoyl, dihydroindocarbazoyl, benzoquinolinyl, acridineyl, dibenzoacridyl, benzoimidazoyl, imidazopyridyl, benzooxazolyl, benzothiazoyl, phenolinyl, etc., which are cyclic aromatic groups having atoms other than carbon in one or more rings. The term "naphthidyl" refers to any one of 1,5-naphthidyl, 1,6-naphthidyl, 1,7-naphthidyl, 1,8-naphthidyl, 2,6-naphthidyl, or 2,7-naphthidyl. The heteroaryl group may or may not have substituents. The number of carbon atoms in the heteroaryl group is not particularly limited, but is preferably in the range of 2 to 40, and more preferably in the range of 2 to 30.

[0068] Furthermore, the heteroaryl group is preferably pyridyl, furanyl, thiophene, quinolinyl, pyrimidinyl, triazine, benzofuranyl, benzothiophene, indolyl, dibenzofuranyl, dibenzothiophene, carbazole, benzimidazolyl, imidazopyridyl, benzoxazolyl, benzothiazolyl, and benzirolinyl; more preferably pyridyl, furanyl, thiophene, and quinolinyl. Pyridyl is particularly preferred.

[0069] Where each substituent is further substituted with a heteroaryl group, the heteroaryl group is preferably pyridyl, furanyl, thiophene, quinolinyl, pyrimidinyl, triazine, benzofuranyl, benzothiophene, indolyl, dibenzofuranyl, dibenzothiophene, carbazoyl, benzimidazolyl, imidazopyridyl, benzoxazolyl, benzothiazolyl, or phenolinyl; more preferably pyridyl, furanyl, thiophene, or quinolinyl. Pyridyl is particularly preferred.

[0070] The term "halogen" refers to an atom selected from fluorine, chlorine, bromine, and iodine. Furthermore, carbonyl, carboxyl, oxycarbonyl, and aminomethyl groups may or may not have substituents. Examples of substituents include alkyl, cycloalkyl, aryl, and heteroaryl groups, which may be further substituted.

[0071] The term "amine group" refers to an substituted or unsubstituted amine group. Examples of substituents for substitution include aryl, heteroaryl, straight-chain alkyl, and branched alkyl groups. Phenyl, naphthyl, pyridyl, and quinolinyl are preferred as aryl and heteroaryl groups. These substituents may also be further substituted. The number of carbon atoms is not particularly limited, but is preferably in the range of 2 to 50, more preferably in the range of 6 to 40, and most preferably in the range of 6 to 30.

[0072] The term "silyl" refers to, for example, alkylsilyl such as trimethylsilyl, triethylsilyl, tributyldimethylsilyl, propyldimethylsilyl, and vinyldimethylsilyl, or arylsilyl such as phenyldimethylsilyl, tributyldiphenylsilyl, triphenylsilyl, and trinaphthylsilyl. The substituents on the silicon may also be further substituted. The number of carbon atoms in the silyl group is not particularly limited, but is preferably in the range of 1 to 30.

[0073] The term "siloxane" refers to, for example, a silicon compound group via an ether bond, such as trimethylsiloxane. Substituents on the silicon may also be further substituted. Additionally, "oxoborogroup" refers to an substituted or unsubstituted oxoborogroup. Examples of substituents for substitution include: aryl, heteroaryl, straight-chain alkyl, branched alkyl, aryl ether, alkoxy, and hydroxyl. Among these, aryl and aryl ether groups are preferred.

[0074] The so-called phosphine oxide group is a group represented by -P(=O)R10R11. The R10R11 of the phosphine oxide group can be selected from the same group as the substituents used in the substitution process.

[0075] Examples of aryl rings with 6 to 30 carbon atoms, whether substituted or unsubstituted in rings Za, Zb, and Zc, include: benzene rings, naphthalene rings, phenanthrene rings, 1,2-benzophenanthrene rings, anthracene rings, pyrene rings, and other aromatic hydrocarbon rings. Among these, a benzene ring is preferred from the viewpoint of ensuring solubility. Additionally, examples of heteroaryl rings with 6 to 30 carbon atoms include: pyridine rings, quinoline rings, benzyline rings, and other aromatic heteroaryl ring structures. Among these, a pyridine ring is preferred from the viewpoint of ease of obtaining starting materials or ease of synthesis.

[0076] In general formula (2), the substituent Ra is preferably a group having 6 to 40 carbon atoms, including the substituent. The substituent Ra is more preferably a substituted or unsubstituted aryl group. Examples of substituted or unsubstituted aryl groups include substituted or unsubstituted phenyl, substituted or unsubstituted biphenyl, substituted or unsubstituted fluorenyl, substituted or unsubstituted naphthyl, substituted or unsubstituted phenanthryl, etc. Among these, a substituted or unsubstituted phenyl group is more preferred.

[0077] In addition, in general formula (3), the substituent Ra is preferably a group that also includes substituents and has 6 to 40 carbon atoms. The substituent Ra is more preferably a substituted or unsubstituted aryl group or a substituted or unsubstituted alkyl group.

[0078] Z1 and Z2 in general formula (2) are preferably oxygen atoms or NRa. The reason is that the π conjugation system of the compound represented by general formula (2) expands well and induces inverse intersystem crossover more efficiently from triplet excited state to singlet excited state, thus further improving durability.

[0079] In addition, E in general formula (2) is preferably boron atom, and E1 and E2 in general formula (3) are preferably BRa. The reason is that the π-conjugation system of the compound represented by general formula (2) or general formula (3) has good expansion efficiency, and the inverse intersystem crossover is more efficiently caused from the triplet excited state to the singlet excited state, thus further improving durability.

[0080] In addition, rings Za, Zb and Zc are preferably benzene rings. The reason is that the π-conjugation system of the compound represented by general formula (2) or general formula (3) has good expansion efficiency, and the inverse intersystem crossover is more efficiently caused from the triplet excited state to the singlet excited state, thus further improving durability.

[0081] The compounds represented by general formula (2) or general formula (3), for example as described in the literature "Advanced Materials" (2016, 28, 2777-2781), are molecules in which the HOMO orbital and LUMO orbital can be separated by the multiple resonance effect through the optimal configuration of electron donor amine nitrogen atoms and electron acceptor boron atoms. From the viewpoint of making it easier to emit delayed fluorescence by clearly separating the HOMO orbital and LUMO orbital and making the singlet excited state and triplet excited state closer, it is preferable that in general formula (2), E is a boron atom with strong electron acceptor, and Z1 and Z2 are both groups with strong electron donor, i.e., NRa.

[0082] Furthermore, the emission spectrum of compounds represented by general formula (2) or general formula (3) becomes sharper than that of compounds formed by bonding an electron donor backbone and an electron acceptor backbone due to the multiple resonance effect of the compound. Therefore, by using compounds represented by general formula (2) or general formula (3) as delayed fluorescent materials, high color purity emission can be obtained. That is, compounds represented by general formula (2) or general formula (3) are beneficial for improving the color gamut of displays, and are therefore better as delayed fluorescent materials. In addition, in compounds represented by general formula (2) or general formula (3), rings Za, Zb, and Zc are mainly present around the E atom in general formula (2) or general formula (3) which are locally present in LUMO orbitals, thus making the LUMO orbitals non-localized from the E atom to each ring. By making the LUMO orbitals non-localized, the multiple resonance effect works efficiently, thus obtaining emission with higher color purity. Furthermore, the E atom in general formula (2) is the atom of E, and in general formula (3) it is each atom of E1 and E2.

[0083] Furthermore, it is more preferable to form a structure in which the substituent Ra of general formula (2) or general formula (3) is bonded to at least one ring of ring Za, ring Zb and ring Zc. The reason is that by bonding the substituent Ra to at least one ring of ring Za, ring Zb and ring Zc, the stereoprotective effect of E in general formula (2) or E1 and E2 in general formula (3) is further improved, and the effect of suppressing the decrease in fluorescence quantum yield can be expected to be further improved.

[0084] Hereinafter, an example of a compound represented by general formula (2) or general formula (3) is shown. However, the compound is not particularly limited to these.

[0085] [Chemical 4]

[0086] The emission wavelength of the delayed fluorescent material is not particularly limited. In order to extract the three primary colors of blue, green and red from the blue light source, the emission wavelength of the delayed fluorescent material when excited by blue light is preferably green or red. That is, the delayed fluorescent material preferably exhibits emission with a peak wavelength observed in the region of 500 nm to less than 580 nm when using excitation light in the range of 400 nm to 500 nm; or exhibits emission with a peak wavelength observed in the region of 580 nm to less than 750 nm when using excitation light in the range of 400 nm to 500 nm.

[0087] In addition, in order to expand the color gamut and improve color reproducibility, it is preferable that the light emission spectra of blue, green and red have little overlap.

[0088] For example, when blue light with a wavelength in the range of 400 nm to 500 nm having a suitable excitation energy is used as the excitation light, emission with a peak wavelength observed in the region of 500 nm or higher is used as green emission. In this case, the overlap between the emission spectra of the excitation light and the green light is reduced, and the color reproducibility is improved, which is therefore preferable. Based on further enhancing its effect, the lower limit of the peak wavelength of emission when the delayed fluorescent material exhibits green emission is preferably 510 nm or higher, more preferably 515 nm or higher, and particularly preferably 520 nm or higher.

[0089] Furthermore, in order to reduce the overlap between the emission spectra of the excitation light and the red light, it is preferable to use the emission with a peak wavelength observed in the region less than 580 nm as the green emission. Further enhancing this effect, the upper limit of the peak wavelength of the emission when the delayed fluorescent material exhibits green emission is preferably 550 nm or less, more preferably 540 nm or less, and particularly preferably 535 nm or less.

[0090] Furthermore, when the emission with a peak wavelength observed in the region of 500 nm or more and less than 580 nm is used as green emission, the emission with a peak wavelength observed in the region of 580 nm or more is used as red emission. In this case, the overlap of the emission spectra of green and red light is reduced, and the color reproducibility is improved, which is therefore preferable. Based on further enhancing its effect, the lower limit of the peak wavelength of emission when the delayed fluorescent material exhibits red emission is preferably 620 nm or more, more preferably 630 nm or more, and particularly preferably 635 nm or more.

[0091] The upper limit of the peak wavelength of red light is only required to be near the upper boundary of the visible region, i.e., below 750 nm. If it is below 700 nm, the visual sensitivity increases, which is even better. On the basis of further increasing its effect, the upper limit of the peak wavelength when the delayed fluorescent material emits red light is preferably below 680 nm, and particularly preferably below 660 nm.

[0092] That is, when blue light with a wavelength in the range of 400 nm to 500 nm is used as the excitation light, the peak wavelength of the green light is preferably 500 nm to 580 nm, more preferably 510 nm to 550 nm, further preferably 515 nm to 540 nm, and especially preferably 520 nm to 530 nm. Additionally, the peak wavelength of the red light is preferably 580 nm to 750 nm, more preferably 620 nm to 700 nm, further preferably 630 nm to 680 nm, and especially preferably 635 nm to 660 nm.

[0093] Furthermore, in order to reduce the overlap of emission spectra and improve color reproducibility, it is preferable that the half-widths (WWs) of the emission spectra for blue, green, and red are small. In particular, the small WWs of the emission spectra for green and red light are effective in improving color reproducibility.

[0094] For example, the half-width at half maximum (WWHM) of the emission spectrum of green light is preferably 50 nm or less, more preferably 40 nm or less, even more preferably 35 nm or less, and particularly preferably 30 nm or less. The half-width at half maximum (WWHM) of the emission spectrum of red light is preferably 80 nm or less, more preferably 70 nm or less, even more preferably 60 nm or less, and particularly preferably 50 nm or less.

[0095] Furthermore, there are no particular restrictions on the shape of the emission spectra in blue, green, and red. For example, since the excitation energy can be utilized efficiently and the color purity is also increased, the emission spectra of these colors are preferably single peaks. Here, a single peak means a state in which there is no peak with an intensity of more than 5% of the intensity of the strongest peak in a certain wavelength region.

[0096] Furthermore, when the organic light-emitting material exhibits green light emission, it is through an excitation state with a higher energy than when it exhibits red light emission. Therefore, organic light-emitting materials exhibiting green light emission (hereinafter, sometimes simply referred to as green light-emitting materials) are inherently more prone to degradation than organic light-emitting materials exhibiting red light emission. In contrast, organic light-emitting materials emitting delayed fluorescence, especially those containing compounds represented by general formula (2) or general formula (3), can achieve both high color purity emission and high durability. Therefore, in order to further improve the durability of the color conversion component, it is preferable that at least the green light-emitting material in the organic light-emitting material of layer (A) is an organic light-emitting material emitting delayed fluorescence. That is, the delayed fluorescence material preferably exhibits emission with a peak wavelength observed in the region of 500 nm or more and less than 580 nm by using excitation light in the range of 400 nm or more and 500 nm or less.

[0097] (A-2. Adhesive Resin) In the color conversion member of the present invention, layer (A) contains, in addition to the at least one delayed fluorescence material, an adhesive resin. The adhesive resin is a material that forms a continuous phase and has excellent processability, transparency, heat resistance, etc. Examples of adhesive resins include: photocurable photoresist materials with reactive vinyl groups such as acrylic, methacrylic, polyvinyl cinnamate, and cyclohexane; epoxy resins, silicone resins (including silicone rubber, silicone gel, and other organopolysiloxane curables (crosslinks)); urea resins; fluororesins; polycarbonate resins; acrylic resins; urethane resins; melamine resins; polyvinyl resins; polyamide resins; phenolic resins; polyvinyl alcohol resins; cellulose resins; aliphatic ester resins; aromatic ester resins; aliphatic polyolefin resins; and aromatic polyolefin resins. In addition, copolymers of these resins may also be used as adhesive resins. By appropriately designing these resins, an adhesive resin that can be effectively used for the (A) layer of the color-converting component of the present invention can be obtained. Among these resins, thermoplastic resins are preferred for ease of molding processes such as sheet forming. Among thermoplastic resins, epoxy resins, silicone resins, acrylic resins, ester resins, olefin resins, or mixtures thereof are preferred for transparency and heat resistance. Furthermore, from the viewpoint of durability, acrylic resins, ester resins, and cycloolefin resins are particularly preferred thermoplastic resins.

[0098] Preferred specific examples of adhesive resins may be cited, for example, those described in International Publication No. 2016 / 190283, International Publication No. 2017 / 61337, International Publication No. 2018 / 43237, International Publication No. 2019 / 21813 and International Publication No. 2019 / 188019.

[0099] In addition, dispersants or leveling agents for stabilizing the coating film may be added to the adhesive resin as additives, and adhesive aids such as silane coupling agents may be added as surface modifiers. Furthermore, inorganic particles such as silica particles or silicone microparticles may be added to the adhesive resin as sedimentation inhibitors for color conversion materials.

[0100] In the color conversion composition used to manufacture layer (A), in order to suppress hardening at room temperature and extend the service life, it is preferable to incorporate a silane retarder, such as ethynyl alcohol, as another component into the adhesive resin. Furthermore, without impairing the effects of the present invention, as needed, microparticles such as silica, glass powder, and quartz powder, inorganic fillers or pigments such as titanium dioxide, zirconium oxide, barium titanate, and zinc oxide, flame retardants, heat resistant agents, antioxidants, dispersants, solvents, and adhesion promoters such as silane coupling agents or titanium coupling agents may also be incorporated into the adhesive resin.

[0101] (A-3. Other luminescent materials) In the color conversion member of the present invention, in addition to the aforementioned delayed fluorescence material, other luminescent materials (other luminescent materials) emitting delayed fluorescence may also be used in layer (A). Examples of such other luminescent materials include: inorganic phosphors, fluorescent pigments, fluorescent dyes, quantum dots, and organic luminescent materials that do not emit delayed fluorescence. Two or more of these other luminescent materials may also be included. To achieve highly efficient color conversion, the other luminescent material is preferably a material exhibiting high quantum yield luminescence characteristics. Specifically, quantum dots and organic luminescent materials that do not emit delayed fluorescence are preferred, and more preferably, organic luminescent materials that do not emit delayed fluorescence are also preferred.

[0102] As organic light-emitting materials that do not emit delayed fluorescence, preferred examples include compounds or derivatives of condensed aryl rings such as naphthalene, anthracene, phenanthrene, pyrene, 1,2-benzophenanthrene, tetraphenylene, triphenylene, perylene, fluoranthene, fluorene, and indene.

[0103] In addition, as organic light-emitting materials that do not emit delayed fluorescence, examples of compounds having heteroaryl rings or their derivatives include furan, pyrrole, thiophene, silole, 9-silafluorene, 9,9'-spirobisilafluorene, benzothiophene, benzofuran, indole, dibenzothiophene, dibenzofuran, imidazopyridine, phenocyanate, pyridine, pyrazine, naphthidine, quinoxaline, pyrrolopyridine, etc., which are preferred.

[0104] In addition, as organic light-emitting materials that do not emit delayed fluorescence, examples of preferred materials include borane derivatives, stilbene derivatives, aromatic acetylene derivatives, tetraphenylbutadiene derivatives, aldazine derivatives, pyrrole methylene derivatives, diketopyrrolo[3,4-c]pyrrole derivatives, and coumarin derivatives. Examples of stilbene derivatives include 1,4-stilbeneylbenzene, 4,4'-bis(2-(4-diphenylaminophenyl)vinyl)biphenyl, and 4,4'-bis(N-(stilbene-4-yl)-N-phenylamino)stilbene. Examples of coumarin derivatives include coumarin 6, coumarin 7, and coumarin 153.

[0105] In addition, as organic light-emitting materials that do not emit delayed fluorescence, azole derivatives such as imidazole, thiazole, thiadiazole, carbazole, oxazole, oxadiazole, and triazole and their metal complexes are preferred.

[0106] Furthermore, as organic light-emitting materials that do not emit delayed fluorescence, anthocyanin compounds, xanthones, or thioxanthates are preferred examples. Examples of anthocyanin compounds include indocyanine green. Examples of xanthones or thioxanthates include fluorescent yellow, eosin, and rose red.

[0107] Furthermore, as organic light-emitting materials that do not emit delayed fluorescence, examples of preferred materials include polyphenylene compounds, naphthadieneimide derivatives, phthalocyanine derivatives and their metal complexes, porphyrin derivatives and their metal complexes, oxazine compounds, and helical hydrocarbon compounds. Examples of oxazine compounds include Nile red or Nile blue.

[0108] Furthermore, as organic light-emitting materials that do not emit delayed fluorescence, aromatic amine derivatives and organometallic complexes are preferred examples. Examples of aromatic amine derivatives include N,N'-diphenyl-N,N'-di(3-methylphenyl)-4,4'-diphenyl-1,1'-diamine. Examples of organometallic complexes include iridium (Ir), ruthenium (Ru), rhodium (Rh), palladium (Pd), platinum (Pt), osmium (Os), and rhenium (Re).

[0109] The organic light-emitting material that does not emit delayed fluorescence can be a fluorescent light-emitting material or a phosphorescent light-emitting material. To achieve high color purity, it is preferably a fluorescent light-emitting material. Among these, pyrrole methylene derivatives are preferred for imparting high fluorescence quantum yield and better color durability. Among pyrrole methylene derivatives, boron complexes of pyrrole methylene are also preferred.

[0110] In addition, in the color conversion component of the present invention, in order to improve the energy transfer efficiency of self-excited light to delayed fluorescent material, the (A) layer may also contain auxiliary dopants such as rubrene.

[0111] (A-4. Other components) In the color conversion component of the present invention, in addition to the delayed fluorescence material and adhesive resin, layer (A) may also contain light stabilizers, antioxidants, processing and heat stabilizers, light-resistant stabilizers such as ultraviolet absorbers, scattering particles, silicone microparticles and silane coupling agents and other components (additives).

[0112] Examples of light stabilizers include, for example, tertiary amines, catechol derivatives, and nickel compounds, or complexes or salts of at least one transition metal selected from the group consisting of Sc, V, Mn, Fe, Co, Cu, Y, Zr, Mo, Ag, and lanthanides, and organic acids, without particular limitation. Furthermore, these light stabilizers can be used alone or in combination.

[0113] Examples of antioxidants include phenolic antioxidants such as 2,6-di-tert-butyl-p-cresol and 2,6-di-tert-butyl-4-ethylphenol, but these are not specifically limited to these. Furthermore, these antioxidants can be used alone or in combination.

[0114] Examples of phosphorus-based stabilizers used as processing and heat stabilizers include, for example, tributyl phosphite, tricyclohexyl phosphite, triethylphosphine, and diphenylbutylphosphine, but are not specifically limited to these. Furthermore, these stabilizers can be used alone or in combination.

[0115] Examples of lightfastness stabilizers include benzotriazoles such as 2-(5-methyl-2-hydroxyphenyl)benzotriazole and 2-[2-hydroxy-3,5-bis(α,α-dimethylbenzyl)phenyl]-2H-benzotriazole, but are not specifically limited to these. Furthermore, these lightfastness stabilizers can be used alone or in combination.

[0116] The scattering particles are preferably inorganic particles with a refractive index of 1.7 or higher and 2.8 or lower. Examples of such inorganic particles include: titanium dioxide, zirconium oxide, aluminum oxide, cerium oxide, tin oxide, indium oxide, iron oxide, zinc oxide, aluminum nitride, aluminum, tin, sulfides of titanium or zirconium, hydroxides of titanium or zirconium, etc.

[0117] In layer (A), the content of these additives, while also depending on the molar absorptivity, luminescence quantum yield, and absorption intensity at the excitation wavelength of the compound, as well as the thickness or transmittance of the layer (A) to be formed, is generally preferably 1.0 × 10⁻³ parts by weight or more and 30 parts by weight or less relative to 100 parts by weight of the adhesive resin. Furthermore, relative to 100 parts by weight of the adhesive resin, the content of these additives is more preferably 1.0 × 10⁻² parts by weight or more and 15 parts by weight or less, and particularly preferably 1.0 × 10⁻¹ parts by weight or more and 10 parts by weight or less.

[0118] Furthermore, from the viewpoint of further improving the durability of the luminescent material, the amount of residual solvent in layer (A) after drying is preferably 3.0% by weight or less, more preferably 1.0% by weight or less, and even more preferably 0.5% by weight or less. Furthermore, from the viewpoint of improving the quantum yield of the luminescent material, the amount of residual solvent is preferably 0.01% by weight or more, more preferably 0.05% by weight or more, and even more preferably 0.1% by weight or more.

[0119] Furthermore, the thickness of layer (A) is not particularly limited, but is preferably 5 μm or more and 1000 μm or less. The lower limit of the thickness of layer (A) is more preferably 10 μm or more. Furthermore, the upper limit of the thickness of layer (A) is more preferably 200 μm or less, more preferably 100 μm or less, and particularly preferably 50 μm or less. The thickness of layer (A) in this invention refers to the film thickness (average film thickness) measured by method A of thickness measurement using mechanical scanning in Japanese Industrial Standards (JIS) K7130 (1999) Plastics - Films and Sheets - Thickness Measurement Method. In addition, layer (A) may be a layer consisting of a single color conversion layer, or it may be a laminate formed by stacking two or more color conversion layers.

[0120] <(B) layer> Layer (B) is an oxygen barrier layer. Oxygen barrier properties refer to the characteristic of low oxygen permeability. In this invention, the oxygen permeability of layer (B) is 1.0 cc / m²·day·atm or less. Preferably, the oxygen permeability of layer (B) is 0.5 cc / m²·day·atm or less, and more preferably 0.1 cc / m²·day·atm or less.

[0121] Furthermore, oxygen permeability refers to the value measured using a planar test piece with uniform film thickness, under conditions of 20°C and 0%RH, using an oxygen permeability measuring device (model name: "OXTRAN" (registered trademark) ("OXTRAN" 2 / 20)) manufactured by MOCON Corporation (USA) and based on the electrolytic sensor method described in JIS K7126-2 (2006).

[0122] If layer (B) can suppress oxygen transmission to layer (A) (color conversion layer), it can be disposed at any position of the color conversion member. From the viewpoint of more reliably suppressing oxygen transmission to layer (A), layer (B) is preferably disposed on at least one of the two sides of layer (A) in the thickness direction, such as layer (B) 12 as shown in FIG. 1. In particular, layer (B) is more preferably laminated in the order of layer (B) / layer (A) / layer (B), such as layer (B) 12 as shown in FIG. 2 and FIG. 3, disposed on both sides of layer (A) in the thickness direction.

[0123] In the color conversion member of the present invention, layer (B) may be directly connected to layer (A), or another layer may be present between layer (A) and layer (B). From the viewpoint of suppressing oxygen permeation to layer (A), it is preferable that layer (B) is directly connected to layer (A), or that the bonding layer described later is present between layer (A) and layer (B) and the bonding layer is laminated.

[0124] Furthermore, layer (B) is preferably transparent so as not to obstruct the light-emitting properties of layer (A). Here, transparency means low absorption and scattering in the visible region; specifically, it means that the total light transmittance is 80% or more. The total light transmittance of layer (B) is preferably 85% or more, and preferably 90% or more.

[0125] In addition, the haze of layer (B) is preferably below 7%. The haze of layer (B) is preferably above 5%, more preferably above 2%, and especially preferably below 1%.

[0126] Furthermore, the total light transmittance and haze were measured using a planar test piece with uniform film thickness, at a temperature of 23°C and a humidity of 50%RH, in accordance with JIS K7361 (1997) and using a haze meter NDH2000 manufactured by Nippon Denshoku Kogyo Co., Ltd.

[0127] In the color conversion component of the present invention, layer (B) is provided for the purpose of further improving the durability of the delayed fluorescent material contained in layer (A).

[0128] Typically, when an organic light-emitting material is excited in the presence of oxygen, an energy transfer (usually called pigment sensitization) occurs between the organic light-emitting material in the triplet excited state and the triplet oxygen in the ground state, thereby generating singlet oxygen. It is known that the generated singlet oxygen causes degradation due to oxidation of the light-emitting material due to its strong oxidizing power.

[0129] As described above, delayed fluorescent materials have the property of rapidly converting triplet excited states into singlet excited states. However, since the generation rate of delayed fluorescent materials in triplet excited states is relatively large, singlet oxygen is generated in the presence of oxygen in layer (A) through pigment sensitization, thereby causing oxidative degradation of the luminescent materials (delayed fluorescent materials, etc.) in layer (A).

[0130] On the other hand, under conditions where oxygen is absent, delayed fluorescence materials exhibit very superior durability compared to other luminescent materials such as organic luminescent materials that do not emit delayed fluorescence.

[0131] For example, organic light-emitting materials include those that change from a singlet ground state to a singlet excited state by photoexcitation, and then change from a singlet excited state to a triplet excited state by intersystem crossing. Typically, organic light-emitting materials in the triplet excited state exhibit high reactivity. Furthermore, when the organic light-emitting material is a non-delayed fluorescence emitting material (a luminescent material other than a delayed fluorescence material), the transition from the triplet excited state to the singlet ground state is a spin-forbidden transition, thus the triplet excited state of the organic light-emitting material has a long lifetime. Therefore, organic light-emitting materials in the triplet excited state readily react with surrounding molecules. As described, in the presence of oxygen, oxygen, which is highly reactive and has a high degree of transfer, becomes the energy receiver from the organic light-emitting material in the triplet excited state, leading to oxidative degradation of the organic light-emitting material. On the other hand, in the absence of oxygen, the molecules surrounding the organic light-emitting material can become the energy receiver. That is, even in the absence of oxygen and the absence of singlet oxygen, if a highly reactive triplet excited organic light-emitting material exists for a long time, the organic light-emitting material will still react with the surrounding molecules, thereby degrading the organic light-emitting material.

[0132] In contrast, when the organic light-emitting material in the triplet excited state is a delayed fluorescent material, the delayed fluorescent material in the triplet excited state rapidly transforms into a delayed fluorescent material in the singlet excited state. Therefore, the reaction between the delayed fluorescent material in the triplet excited state and its surrounding molecules is difficult to occur, thus making it difficult to cause degradation of the delayed fluorescent material due to this reaction, and exhibiting excellent durability of the delayed fluorescent material.

[0133] That is, by using layer (B) to suppress the intrusion of oxygen into layer (A), the delayed fluorescent material in layer (A) can exhibit significantly better durability than the organic light-emitting material in the previous color conversion component.

[0134] Furthermore, in order to rapidly convert the triplet excited state to the singlet excited state in the delayed fluorescent material, it is preferable that the electron density of the intramolecular electron donor framework of the delayed fluorescent material is moderately high. For example, the HOMO energy level of the delayed fluorescent material is preferably -5.7 eV or higher. In this case, the improvement in durability of the delayed fluorescent material brought about by the (B) layer is greater. Among them, when the HOMO energy level of the delayed fluorescent material is -5.6 eV or higher, the improvement in durability is further greater. When the HOMO energy level of the delayed fluorescent material is -5.5 eV or higher, the improvement in durability is particularly greater.

[0135] The HOMO energy level of a compound can be calculated. In this invention, the HOMO energy level is set as follows: using the general quantum chemistry calculation program "Gaussian 16" (manufactured by Gaussian Corporation), the structure is optimized using B3LYP density functional theory with a 6-31G(d) basis system, and the optimized structure is calculated using B3LYP density functional theory with a 6-311++G(d,p) basis system.

[0136] The (B) layer is preferably an inorganic oxide layer or an inorganic nitride layer. Examples of layers included in the (B) layer include: layers containing inorganic oxides such as silicon oxide, aluminum oxide, titanium oxide, tantalum oxide, zinc oxide, tin oxide, indium oxide, yttrium oxide, and magnesium oxide; or layers containing inorganic nitrides such as silicon nitride, aluminum nitride, titanium nitride, and silicon carbonitride; metal oxide layers or metal nitride layers formed by adding other elements to these; or layers containing various resins such as polyvinylidene chloride, acrylic resins, silicone resins, melamine resins, carbamate resins, fluorinated resins, and polyvinyl alcohol saponins. The (B) layer may contain two or more of these. From a cost perspective, silicon oxide and aluminum oxide are preferred as the metal oxide constituting the (B) layer, with aluminum oxide being particularly preferred. From the viewpoint of high oxygen barrier properties, polyol-based resins are preferred as the resin constituting layer (B). Among them, saponifications of vinyl acetate such as polyvinyl alcohol or ethylene-vinyl alcohol copolymers, and mixtures containing such resins are even more preferred because of their particularly excellent oxygen barrier properties.

[0137] Furthermore, layer (B) is preferably a cured layer comprising a resin composition including a polyol resin and a silicone compound having an alkoxy group and its hydrolysate. This is because, by forming a cross-linked structure via silicone, the swelling of the polyol resin can be suppressed, maintaining high oxygen barrier properties even under high temperature and humidity conditions. Furthermore, layer (B) exhibits even higher gas barrier properties in the case of a laminated structure having the cured layer of the resin composition and the inorganic oxide layer or inorganic nitride layer, and is therefore particularly preferred.

[0138] <Other Layers> In addition to the (A) layer and (B) layer described above, the color conversion component of the present invention may also have various layers as needed, such as a substrate layer, an adhesive layer and a functional layer, as shown below.

[0139] (Substrate Layer) The substrate layer (e.g., substrate layer 10 shown in Figures 1 to 3) in the color conversion member of the present invention can be, for example, glass or resin film. As a resin film, polyethylene terephthalate (PET), polyphenylene sulfide, polycarbonate, polypropylene, polyimide, or other plastic films are preferred. Regarding ease of film peeling, the substrate layer can also be pre-treated with a release agent. Similarly, to improve interlayer adhesion, the substrate layer can also be pre-treated with an easy-adhesion treatment. The thickness of the substrate layer is not particularly limited, but as a lower limit, it is preferably 25 μm or more, more preferably 38 μm or more. Furthermore, as an upper limit, it is preferably 5000 μm or less, more preferably 3000 μm or less.

[0140] (Adhesive Layer) In the color conversion member of the present invention, an adhesive layer may be provided between layers such as layer (A) and layer (B) as needed. As the adhesive layer, known materials may be used without particular restriction, as long as they do not excessively affect the luminescence and durability of the color conversion member. When a strong bond between the layers is required, photocurable materials, thermocurable materials, anaerobic curable materials, and thermoplastic materials may be preferably used as the adhesive layer. Among these, thermocurable materials are more preferred, and thermocurable materials that can be cured at temperatures above 0°C and below 150°C are particularly preferred.

[0141] (Other functional layers) The color conversion component of the present invention may further have a light diffusion layer, an adhesive layer, an auxiliary layer with anti-reflection function, anti-glare function, anti-reflection and anti-glare function, hard coating function (abrasion resistance function), antistatic function, anti-fouling function, electromagnetic wave shielding function, infrared cut-off function, ultraviolet cut-off function, water vapor blocking function, polarizing function, color adjustment function, etc., depending on the required function.

[0142] (Other films) The color conversion component of the present invention may further include polarizing reflective films, diffusers, prisms, wavelength selective reflective films, etc. As preferred specific examples of wavelength selective reflective films, those described in International Publication No. 2017 / 164155 and Japanese Patent Application Publication No. 2018-81250 may be cited.

[0143] <Manufacturing Method of Color Conversion Component> Hereinafter, an example of a manufacturing method of the color conversion component of the present invention will be described. In this manufacturing method of the color conversion component, firstly, a color conversion composition for making layer (A) is manufactured as follows.

[0144] In the method for manufacturing the color conversion composition, the delayed fluorescence material, adhesive resin, and additives as needed are mixed in a predetermined amount. At this time, a solvent may also be mixed as needed.

[0145] The solvent is not particularly limited as long as it is a resin whose viscosity can be adjusted to maintain its flow state and does not excessively affect the luminescence and durability of the luminescent material. Examples of such solvents include: 2-propanol, ethyl acetate, butyl acetate, toluene, methyl ethyl ketone, methyl isobutyl ketone, hexane, acetone, terpineol, texanol, methyl cellosolve, butyl carbitol, butyl carbitol acetate, propylene glycol monomethyl ether acetate, etc. Two or more of these solvents may also be used in combination. Among these solvents, ethyl acetate or toluene is preferred, especially in terms of not affecting the deterioration of the compound represented by general formula (2) or general formula (3) and having less residual solvent after drying.

[0146] After mixing the components in a manner that constitutes a predetermined composition, the mixture is homogenized and dispersed using a mixing-kneading machine to obtain a color conversion composition for the production of layer (A). Examples of mixing-kneading machines include: homogenizers, rotary mixers, three-roll mixers, ball mills, planetary ball mills, and bead mills. Degassing can be preferably performed under vacuum or reduced pressure conditions after or during the mixing and dispersion process. In addition, a specific component can be pre-mixed or subjected to aging treatments. The desired concentration of solid components can also be obtained by removing the solvent using an evaporator.

[0147] Next, the color conversion composition for making layer (A) obtained as described is applied to a substrate such as a substrate layer or layer (B) and dried. This forms layer (A). If the adhesive resin contained in the color conversion composition is a thermosetting resin, layer (A) can be formed by applying the color conversion composition to a substrate such as a substrate layer and then curing it by heat. If the adhesive resin contained in the color conversion composition is a photocurable resin, layer (A) can be formed by applying the color conversion composition to a substrate such as a substrate layer and then curing it by light.

[0148] The coating of the color conversion composition used in the (A) layer can be performed using a reverse roll coater, blade coater, corner wheel coater, slot die coater, direct gravure coater, flatbed gravure coater, coincident coater, natural roll coater, air knife coater, roller blade coater, two-stream coater, bar coater, wire bar coater, applicator, dip coater, curtain coater, spin coater, doctor blade coater, etc. In order to obtain high film thickness uniformity of the (A) layer, it is preferable to use a slot die coater, corner wheel coater, or dip coater for coating.

[0149] Drying of layer (A) can be performed using a general heating device such as a hot air dryer or an infrared dryer. In this case, the heating temperature is preferably 60°C to 200°C, and the heating time is preferably 2 minutes to 4 hours. Alternatively, layer (A) can be heat-cured in stages using methods such as step cure.

[0150] When layer (A) is formed by heat curing, a hot air oven or similar device can be used as the heating apparatus. The heating conditions for heat curing layer (A) can be selected according to the adhesive resin. For example, the heating temperature is preferably 100°C to 300°C, and the heating time is preferably 1 minute to 2 hours.

[0151] When the (A) layer is formed by photocuring, it is preferable to irradiate the (A) layer with high-energy light such as ultraviolet light. The light irradiation conditions during the photocuring of the (A) layer can be selected according to the adhesive resin. For example, the wavelength of the irradiated light is preferably 200 nm to 500 nm, and the irradiation intensity is preferably 10 mJ / cm2 to 10 J / cm2.

[0152] After the (A) layer is fabricated, the substrate layer may be changed as needed. In this case, as a simple method, for example, the method of changing the substrate using a heating plate, or the method of using a vacuum laminator or a dry film laminator, etc.

[0153] In the manufacturing method of the color conversion member of the present invention, the method for forming layer (B) is not particularly limited. For example, as a method for forming layer (B), the following can be listed: a method of coating a resin composition for making layer (B) onto a substrate such as a substrate layer or layer (A) and drying and hardening it; or a method of laminating a film formed by steps such as extrusion or biaxial stretching, coating onto a substrate such as a substrate layer or vapor deposition.

[0154] Furthermore, in the manufacturing method of the color conversion member of the present invention, there is no particular limitation on the method of laminating layers such as layer (A) and layer (B). For example, as a method of laminating each layer, the following can be listed: a method of forming layer (A) by coating and drying layer (B); or a method of forming layer (B) by coating and drying layer (A); a method of bonding a pre-formed self-supporting film for layer (B) onto layer (A); a method of bonding a pre-formed self-supporting film for layer (A) onto layer (B); a method of bonding multiple separately fabricated laminating units together, such as bonding the laminating units of "substrate layer / (B) layer / (A) layer" with the laminating units of "(B) layer / substrate". For the purpose of improving the stability of the laminated film, it is also preferable to further perform a heat curing step or a curing step on the laminated body after obtaining the laminated body (laminated unit) for the required layers.

[0155] The thickness of the color-converting member manufactured by the aforementioned manufacturing method into a sheet or similar shape is preferably 30 μm or more and 300 μm or less. Here, the thickness of the color-converting member refers to the total thickness of all layers contained in the color-converting member, and is the film thickness (average film thickness) measured by method A of mechanical scanning thickness measurement in JIS K7130 (1999) Plastics - Films and Sheets - Thickness Measurement Methods. By setting the thickness of the color-converting member of the present invention to 30 μm or more, the strength and toughness of the color-converting member can be improved. In addition, by setting the thickness of the color-converting member of the present invention to 300 μm or less, cracking of the color-converting member can be suppressed.

[0156] <Light Source Unit> The light source unit (hereinafter sometimes simply referred to as the light source unit of the present invention) according to the embodiments of the present invention includes at least a light source and the color conversion member. The light source included in the light source unit of the present invention is the source of the excitation light. There are no particular limitations on the arrangement of these light sources and color conversion members. A structure in which the light source and the color conversion member are in close contact can be adopted, or a remote phosphor form in which the light source and the color conversion member are separated can be adopted. In addition, for the purpose of improving color purity, the light source unit of the present invention may further adopt a structure including a color filter.

[0157] <Light Source> Any type of light source can be used if the light source included in the light source unit of the present invention emits light in a wavelength region that can be absorbed by the luminescent material in layer (A). For example, any light source that excites light, such as a hot cathode tube or cold cathode tube, a fluorescent light source such as inorganic electroluminescence (EL), an organic EL element light source, an LED light source, an incandescent light source, or sunlight, can be used in principle. Among these, an LED light source is preferred. For example, a light-emitting diode that emits a large amount of light in a wavelength range of 400 nm to 500 nm is a more preferred LED light source. In display or lighting applications, in terms of improving the color purity of blue light, a light-emitting diode (blue LED light source) that emits a large amount of light in a wavelength range of 430 nm to 500 nm is a further preferred light source.

[0158] The light source may have one emission peak or two or more emission peaks. To improve color purity, it is preferable to have one emission peak. Alternatively, multiple light sources with different types of emission peaks can be arbitrarily combined for use.

[0159] The light source unit of the present invention is effectively used in various light sources such as spatial lighting and backlighting. Specifically, the light source unit of the present invention can be used in displays, lighting devices, interiors, signs, billboards, etc., and is particularly preferably used in displays or lighting devices.

[0160] <Display, Lighting Device> The display according to the embodiments of the present invention includes at least the aforementioned light source unit. For example, in displays such as liquid crystal displays, a light source unit having the aforementioned light source and color conversion member is used as a backlight unit. Furthermore, the lighting device according to the embodiments of the present invention includes at least the aforementioned light source unit. For example, this lighting device is configured such that a blue LED light source serving as the light source unit is combined with a color conversion member that converts blue light from the blue LED light source into light with a wavelength longer than the blue light, thereby emitting white light. [Example]

[0161] Hereinafter, embodiments are given to illustrate the present invention, but the present invention is not limited to the following embodiments. First, the evaluation methods in the embodiments and comparative examples will be described.

[0162] <Durability Evaluation> In the durability evaluation, in each embodiment and comparative example, a current of 30 mA was passed through the light-emitting device equipped with a fabricated color conversion component and a blue LED element (manufactured by Ushio EPITEX; model SMBB450H-1100, peak emission wavelength: 450 nm) to illuminate the blue LED element, and the initial peak emission intensity was measured using a spectroradiometer (CS-1000, manufactured by Konica Minolta). Furthermore, the distance between the color conversion component and the blue LED element in the light-emitting device was set to 3 cm. Subsequently, light from the blue LED element was continuously irradiated at 50°C, and the time until the peak emission intensity decreased by 5% was observed to evaluate the durability of the color conversion component.

[0163] <Determination of Oxygen Permeability> In the determination of oxygen permeability, for the (B) layer (oxygen barrier layer) which is the object of evaluation, a planar test piece with uniform film thickness is used. Unless otherwise specified, the oxygen permeability is determined using an oxygen permeability measuring device (model name: "OXTRAN" (registered trademark) ("OXTRAN" 2 / 20) manufactured by MOCON Corporation (USA) under the conditions of temperature 20°C and humidity 0%RH, and based on the electrolytic sensor method described in JIS K7126-2 (2006).

[0164] <Determination of total light transmittance> In the determination of total light transmittance, for the (B) layer (oxygen barrier layer) which is the object of evaluation, a planar test piece with uniform film thickness was used, and the total light transmittance was measured according to JIS K7361 (1997) and by a haze meter (NDH2000) manufactured by Nippon Denshoku Kogyo Co., Ltd. under the conditions of temperature 23°C and humidity 50%RH.

[0165] <Luminescent Material> In the following examples and comparative examples, compounds G-1 to G-8 were used as luminescent materials contained in the color conversion layer, i.e., layer (A). Compounds G-1 to G-8 are the compounds shown below. Among these, compounds G-1, G-4, G-5, G-6, and G-7 are compounds that emit delayed fluorescence (delayed fluorescence materials).

[0166] [Chemical 5]

[0167] [Chemical 6]

[0168] <Resin> In the following examples and comparative examples, polymethyl methacrylate resin "BR-85" (manufactured by Mitsubishi Chemical Corporation, glass transition temperature: 105°C) was used as the adhesive resin. In addition, polyester resin "Vylon" (registered trademark) 630 (manufactured by Toyobo Corporation) was used as the resin for the adhesive layer.

[0169] <Scattering Material> In the following examples and comparative examples, titanium dioxide particles "JR-301" (manufactured by Teikoku Chemical Co., Ltd.) were used as scattering materials.

[0170] Example 1 In Example 1, 0.34 parts by weight of compound G-1 as a luminescent material, 3 parts by weight of titanium dioxide particles (JR-301) as a scattering material, and 300 parts by weight of ethyl acetate as a solvent were mixed with 100 parts by weight of adhesive resin (BR-85). The mixture was then stirred and degassed at 1000 rpm for 20 minutes using a planetary stirring and degassing apparatus, MAZERUSTAR (registered trademark) KK-400 (manufactured by Kurashiki Textile Co., Ltd.), to obtain a color conversion composition for use as a resin composition in the production of a color conversion layer.

[0171] Next, the color conversion composition obtained as described was coated onto "Cerapeel" BLK (a release film manufactured by Toray Film Processing Co., Ltd.) using a slot die coating machine, and heated and dried at 120°C for 20 minutes. Thereby, a color conversion layer ((A) layer) with an average film thickness of 20 μm was formed.

[0172] Next, a thermosetting adhesive layer was formed on a polyethylene terephthalate film "Lumirror" (registered trademark) U48 (manufactured by Toray Industries, Inc., 50 μm thick) serving as the substrate layer using a coating method, and an ethylene-vinyl alcohol copolymer film (ethylene content 32 mol%, thickness 12 μm, total light transmittance 90%) was laminated on it as an oxygen barrier layer ((B) layer). Thus, an oxygen barrier laminated film 1 was produced. The oxygen transmittance of this oxygen barrier laminated film 1 using ethylene-vinyl alcohol copolymer is approximately 0.7 cc / m²·day·atm. In Example 1, two sheets of this oxygen barrier laminated film 1 were prepared.

[0173] Subsequently, a thermosetting adhesive layer is formed on the ethylene-vinyl alcohol copolymer film side of one of the two oxygen barrier laminated films 1 using a coating method, and the color conversion layer is laminated on it. Then, the "Cerapeel" BLK is peeled off from the color conversion layer.

[0174] Finally, a thermosetting adhesive layer is formed on the ethylene-vinyl alcohol copolymer film side of another oxygen barrier laminate 1 using a coating method, and this thermosetting adhesive layer is laminated onto the color conversion layer after the "Cerapeel" BLK has been peeled off. In this way, a sheet-like color conversion member with the structure illustrated in FIG3 is produced. In Example 1, the average film thickness of the thermosetting adhesive layer is 0.50 μm. Furthermore, the thermosetting adhesive layer is not shown in FIG3.

[0175] Using this sheet-like color conversion component to convert the light (blue light) from the blue LED element, if only the green light emission region is selected, high-color-purity green emission with a peak wavelength of 519 nm and a half-width of 38 nm at the peak wavelength can be obtained. Furthermore, when light from the blue LED element is continuously irradiated at 50°C, the time until the peak emission intensity decreases by 5% (light durability) is 800 hours. In Example 1, compared to Comparative Example 1 described later, an improvement of approximately 53 times in light durability is shown.

[0176] Example 2 In Example 2, 0.34 parts by weight of compound G-1 as a luminescent material, 3 parts by weight of titanium dioxide particles (JR-301) as a scattering material, and 300 parts by weight of ethyl acetate as a solvent were mixed with 100 parts by weight of adhesive resin (BR-85). The mixture was then stirred and degassed at 1000 rpm for 20 minutes using a planetary stirring and degassing apparatus, MAZERUSTAR (registered trademark) KK-400 (manufactured by Kurashiki Textile Co., Ltd.), thereby obtaining a color conversion composition for use as a resin composition in the production of a color conversion layer.

[0177] Next, the color conversion composition obtained as described was coated onto "Cerapeel" BLK (a release film manufactured by Toray Film Processing Co., Ltd.) using a slot die coating machine, and heated and dried at 120°C for 20 minutes. Thereby, a color conversion layer ((A) layer) with an average film thickness of 20 μm was formed.

[0178] Next, a water / 2-propanol mixture of polyvinyl alcohol resin was applied to a polyethylene terephthalate film "Lumirror" (registered trademark) U48 (manufactured by Toray Industries, Inc., 50 μm thick) serving as the substrate layer using a rod coating method. The film was then dried at 120°C for 5 minutes to form a coating layer (polyvinyl alcohol resin layer) with an average film thickness of 0.50 μm as layer (B). This produced the oxygen barrier laminate 2. The total light transmittance of the polyvinyl alcohol resin layer was 91%. Furthermore, the oxygen transmittance of the oxygen barrier laminate 2 using the polyvinyl alcohol resin layer was approximately 0.4 cc / m²·day·atm. In Example 2, two sheets of this oxygen barrier laminate 2 were prepared.

[0179] Subsequently, a thermosetting adhesive layer is formed on the polyvinyl alcohol resin layer of one of the two oxygen barrier laminated films 2 using a coating method, and the color conversion layer is laminated on it. Then, the "Cerapeel" BLK is peeled off from the color conversion layer.

[0180] Finally, a thermosetting adhesive layer is formed on the polyvinyl alcohol resin layer of another oxygen-barrier laminate 2 using a coating method, and this thermosetting adhesive layer is laminated onto the color conversion layer after the "Cerapeel" BLK has been peeled off. This produces a sheet-like color conversion component with the structure illustrated in FIG3. In Example 2, the average film thickness of the thermosetting adhesive layer is 0.50 μm. Furthermore, the thermosetting adhesive layer is not shown in FIG3.

[0181] Using this sheet-like color conversion component to convert the light (blue light) from the blue LED element, if only the green light emission region is selected, high-color-purity green emission with a peak wavelength of 519 nm and a half-width of 38 nm at the peak wavelength can be obtained. Furthermore, when light from the blue LED element is continuously irradiated at 50°C, the time until the peak emission intensity decreases by 5% (light durability) is 1000 hours. In Example 2, compared to Comparative Example 1 described later, an improvement of approximately 67 times in light durability is shown.

[0182] Comparative Example 1 In Comparative Example 1, after preparing the color conversion composition in the same manner as in Example 1, the color conversion composition was applied to a polyethylene terephthalate film "Lumirror" (registered trademark) U48 (manufactured by Toray Industries, Inc., thickness 50 μm, oxygen transmittance approximately 40 cc / m2·day·atm, total light transmittance 89%) as the substrate layer using a slot die coater, and then heated and dried at 120°C for 20 minutes. Thereby, a color conversion layer ((A) layer) with an average film thickness of 20 μm was formed.

[0183] Next, a thermosetting adhesive layer was formed on another polyethylene terephthalate film, "Lumirror" (registered trademark) U48, using a coating method, and this thermosetting adhesive layer was laminated onto the color conversion layer of Comparative Example 1. In this way, a sheet-like color conversion member with a structure consisting of two polyethylene terephthalate films sandwiching the color conversion layer was fabricated. This sheet-like color conversion member does not have layer (B).

[0184] Using this sheet-like color conversion component to convert the light (blue light) from the blue LED element, if only the green light emission region is selected, high-color-purity green emission with a peak wavelength of 519 nm and a half-width of 38 nm in the emission spectrum at the peak wavelength can be obtained. Furthermore, when light from the blue LED element is continuously irradiated at 50°C, the time until the emission peak intensity decreases by 5% (light durability) is 15 hours.

[0185] Comparative Example 2 In Comparative Example 2, 0.20 parts by weight of compound G-2 was used as the luminescent material (organic luminescent material) for the color conversion layer. Otherwise, the sheet-like color conversion component was fabricated and evaluated in the same manner as in Example 1. Using this sheet-like color conversion component, light (blue light) from a blue LED element was converted. As a result, if only the green light emission region was selected, high-color-purity green light emission with a peak wavelength of 526 nm and a half-width of 29 nm in the emission spectrum at the peak wavelength was obtained. Furthermore, light from the blue LED element was continuously irradiated at 50°C. As a result, the time until the emission peak intensity decreased by 5% (light durability) was 500 hours. The light durability of the sheet-like color conversion component of Comparative Example 2 was approximately 0.47 times that of Example 1.

[0186] Comparative Example 3 In Comparative Example 3, 0.20 parts by weight of compound G-2 was used as the luminescent material (organic luminescent material) for the color conversion layer. Otherwise, the sheet-like color conversion component was fabricated and evaluated in the same manner as in Comparative Example 1. Using the sheet-like color conversion component, light (blue light) from a blue LED element was converted. As a result, if only the green light emission region was selected, high-color-purity green light emission with a peak wavelength of 526 nm and a half-width of 29 nm in the emission spectrum at the peak wavelength could be obtained. In addition, light from a blue LED element was continuously irradiated at 50°C. As a result, the time until the emission peak intensity decreased by 5% (light durability) was 20 hours.

[0187] Comparative Example 4 In Comparative Example 4, 0.20 parts by weight of compound G-3 was used as the luminescent material (organic luminescent material) for the color conversion layer. Otherwise, the sheet-like color conversion component was fabricated and evaluated in the same manner as in Example 1. Using this sheet-like color conversion component, light (blue light) from a blue LED element was converted. As a result, if only the green light emission region was selected, green light emission with a peak wavelength of 490 nm and a half-width at half-maximum (WHM) of the emission spectrum at the peak wavelength was obtained. Furthermore, light from the blue LED element was continuously irradiated at 50°C. As a result, the time until the emission peak intensity decreased by 5% (light durability) was 300 hours. The light durability of the sheet-like color conversion component of Comparative Example 4 was approximately 0.23 times that of Example 1.

[0188] Comparative Example 5 In Comparative Example 5, 0.20 parts by weight of compound G-3 was used as the luminescent material (organic luminescent material) for the color conversion layer. Otherwise, the sheet-like color conversion component was fabricated and evaluated in the same manner as in Comparative Example 1. Using the sheet-like color conversion component, light (blue light) from a blue LED element was color converted. As a result, if only the green light emission region was selected, green light emission with a peak wavelength of 490 nm and a half-width of 55 nm at the peak wavelength was obtained. Furthermore, light from the blue LED element was continuously irradiated at 50°C. As a result, the time until the peak emission intensity decreased by 5% (light durability) was 25 hours.

[0189] Example 3 In Example 3, 0.34 parts by weight of compound G-1 as a luminescent material, 3 parts by weight of titanium dioxide particles (JR-301) as a scattering material, and 300 parts by weight of ethyl acetate as a solvent were mixed with 100 parts by weight of adhesive resin (BR-85). The mixture was then stirred and degassed at 1000 rpm for 20 minutes using a planetary stirring and degassing apparatus, MAZERUSTAR (registered trademark) KK-400 (manufactured by Kurashiki Textile Co., Ltd.), to obtain a color conversion composition for use as a resin composition in the production of a color conversion layer.

[0190] Next, the color conversion composition obtained as described was coated onto "Cerapeel" BLK (a release film manufactured by Toray Film Processing Co., Ltd.) using a slot die coating machine, and heated and dried at 120°C for 20 minutes. Thereby, a color conversion layer ((A) layer) with an average film thickness of 20 μm was formed.

[0191] Next, tetraethyl orthosilicate (1.2 g), 2-propanol (0.5 g), and methanol (0.5 g) were mixed. Then, an aqueous solution of hydrochloric acid, consisting of 4 g of 0.1 N hydrochloric acid and 5 g of water, was slowly added dropwise to the mixture. Subsequently, 0.4 g of polyvinyl alcohol resin (with a saponification degree of 98 moles or more), which is a polyol resin, was mixed with the mixture after the addition of the aqueous hydrochloric acid solution and stirred. This yielded a resin solution for layer (B).

[0192] Next, the resin solution for layer (B) obtained as described was applied to an alumina-deposited polyethylene terephthalate film, "BARRIALOX" (registered trademark) 1011HG (manufactured by Toray Industries, Inc., 12 μm thick), using a rod coating method. The film was then dried at 150°C for 1 minute to form a coating layer with an average film thickness of approximately 1 μm as layer (B). This process produced an oxygen-barrier laminated film 3. The oxygen transmittance of this oxygen-barrier laminated film 3 was approximately 0.2 cc / m²·day·atm. Furthermore, the total light transmittance of this coating layer was 89%.

[0193] Subsequently, using the oxygen-barrier laminated film 3, a sheet-like color conversion member with the structure illustrated in FIG3 was fabricated and evaluated in the same manner as in Example 2. Using this sheet-like color conversion member to convert the light (blue light) from the blue LED element, it was found that, by selecting only the green light emission region, a high-color-purity green emission with a peak wavelength of 519 nm and a half-width of 38 nm at the peak wavelength was obtained. Furthermore, when light from the blue LED element was continuously irradiated at 50°C, the time until the peak emission intensity decreased by 5% (light durability) was 1200 hours. In Example 3, compared to Comparative Example 1, an improvement of approximately 80 times in light durability was observed.

[0194] Examples 4 to 7 In Examples 4 to 7, as the luminescent material (organic luminescent material) of the color conversion layer, compounds G-4 to G-7 were used respectively, adjusted to the same amount as compound G-1 in Example 2 and mixed. Otherwise, the sheet-like color conversion component was fabricated and evaluated in the same manner as in Example 2.

[0195] Comparative Examples 6 to 9 In Comparative Examples 6 to 9, as the luminescent material (organic luminescent material) of the color conversion layer, compounds G-4 to G-8 were used respectively, adjusted to the same amount as compound G-1 of Comparative Example 1 and mixed. Otherwise, the sheet-like color conversion component was fabricated and evaluated in the same manner as in Comparative Example 1.

[0196] Comparative Example 10 In Comparative Example 10, as the luminescent material (organic luminescent material) of the color conversion layer, compound G-8 was used, and the amount of compound G-2 of Comparative Example 2 was adjusted to be the same and mixed. Otherwise, the sheet-like color conversion component was fabricated and evaluated in the same manner as in Comparative Example 2.

[0197] Comparative Example 11 In Comparative Example 11, as the luminescent material (organic luminescent material) of the color conversion layer, compound G-8 was used, and the amount of compound G-2 of Comparative Example 3 was adjusted to be the same as that of Comparative Example 3 and mixed. Otherwise, the sheet-like color conversion component was fabricated and evaluated in the same manner as in Comparative Example 3.

[0198] The structure and evaluation results of the sheet-like color conversion components of Examples 1 to 7 and Comparative Examples 1 to 11 are shown in Table 1.

[0199] [Table 1] (Table 1) (A) layer Luminescent materials HOMO energy level (eV) (B) layer oxygen barrier layer Oxygen permeability (20℃, 0%RH) (cc / m) 2 (dayatm) peak wavelength (nm) Half-width (nm) Light durability (h) Example 1 G-1 -5.4 oxygen barrier laminated membrane 1 0.7 519 38 800 Example 2 G-1 -5.4 oxygen barrier laminated membrane 2 0.4 519 38 1000 Example 3 G-1 -5.4 oxygen barrier laminated membrane 3 0.2 519 38 1200 Example 4 G-4 -5.6 oxygen barrier laminated membrane 2 0.4 516 38 1300 Example 5 G-5 -5.8 oxygen barrier laminated membrane 2 0.4 518 30 1200 Example 6 G-6 -5.5 oxygen barrier laminated membrane 2 0.4 520 30 700 Actual example 7 G-7 -5.3 Barrier laminated film 2 0.4 460 80 600 Comparative Example 1 G-1 -5.4 Nothing 40 519 38 15 Comparative Example 2 G-2 -5.7 Barrier laminated film 1 0.7 526 29 500 Comparative Example 3 G-2 -5.7 Nothing 40 526 29 20 Comparative Example 4 G-3 -5.6 Barrier laminated film 1 0.7 490 55 300 Comparative Example 5 G-3 -5.6 Nothing 40 490 55 twenty five Comparative Example 6 G-4 -5.6 Nothing 40 516 38 twenty five Comparative Example 7 G-5 -5.8 Nothing 40 518 30 40 Comparative Example 8 G-6 -5.5 none 40 520 30 15 Comparative Example 9 G-7 -5.3 none 40 460 80 15 Comparative Example 10 G-8 -5.9 oxygen barrier laminated membrane 1 0.7 526 29 600 Comparative Example 11 G-8 -5.9 none 40 526 29 25

[0200] As shown in Table 1, when the (A) layer containing the organic light-emitting material G-1 that emits delayed fluorescence is combined with the oxygen-barrier (B) layer, as is evident from the comparison of Example 1, Example 2, Example 3 and Comparative Example 1, the effect of improving light durability is very significant.

[0201] Furthermore, as shown in Table 1, when the (A) layer, which contains compound G-2 or compound G-3, an organic light-emitting material that does not emit delayed fluorescence, is combined with an oxygen-barrier (B) layer, as clearly demonstrated by the comparison between Comparative Examples 2 and 3 or Comparative Examples 4 and 5, the light durability is indeed improved compared to the case where the oxygen-barrier (B) layer is absent. However, the improvement in light durability in this case is not as significant as when the (A) layer contains an organic light-emitting material that emits delayed fluorescence, namely compound G-1.

[0202] Based on the above, the effect of improving light durability when the (A) layer of the organic light-emitting material containing the delayed fluorescence compound G-1 is combined with the oxygen-barrier (B) layer is a very significant effect that greatly exceeds the effect predicted according to the prior art.

[0203] Regarding the excellent improvement in light durability, as shown in Table 1, this can also be observed in delayed fluorescence materials other than compound G-1, namely compounds G-4 to G-7. Furthermore, when comparing Example 4 with Comparative Example 6, and comparing Example 5 with Comparative Example 7, the improvement in light durability using compound G-4 with a HOMO level of -5.6 eV is approximately 52 times, while the improvement in light durability using compound G-5 with a HOMO level of -5.8 eV is approximately 30 times. Based on this comparison result, it is found that when using compound G-4 with a HOMO level of -5.7 eV or higher, a greater effect is shown in improving light durability. On the other hand, when comparing Comparative Example 2 with Comparative Example 3, and comparing Comparative Example 10 with Comparative Example 11, the difference in effect caused by the HOMO level is not observed when using compound G-2, which is not a delayed fluorescence material. That is, it is found that this difference in effect is a characteristic difference observed in the present invention. [Industry availability]

[0204] As described above, the color conversion component, light source unit, display and lighting device involved in the present invention are adapted to achieve both improved color reproduction and improved durability. [Simplified Explanation of the Diagram]

[0012] FIG1 is a schematic cross-sectional view showing a first example of a color conversion member according to an embodiment of the present invention. FIG2 is a schematic cross-sectional view showing a second example of a color conversion member according to an embodiment of the present invention. FIG3 is a schematic cross-sectional view showing a third example of a color conversion member according to an embodiment of the present invention.

Claims

1. A color conversion component for converting incident light into light with a wavelength different from the incident light, characterized in that: it comprises at least the following (A) layer and (B) layer, wherein the (A) layer is a color conversion layer containing at least one organic light-emitting material that emits delayed fluorescence and an adhesive resin, the (B) layer is a layer with an oxygen transmittance of 1.0 cc / m2·day·atm or less, and the organic light-emitting material is a compound containing a partial structure represented by the following general formula (1), wherein in the general formula (1), B is a boron atom, N is a nitrogen atom, C is a carbon atom; n is an integer greater than or equal to 0 and less than or equal to 2; when n is 0, the partial structure represented by the general formula (1) represents a direct bond structure between B and N.

2. A color conversion component for converting incident light into light with a wavelength different from the incident light, characterized in that: it comprises at least the following (A) layer and (B) layer, wherein the (A) layer is a color conversion layer containing at least one organic light-emitting material that emits delayed fluorescence and an adhesive resin, the (B) layer is a layer with an oxygen transmittance of less than 1.0 cc / m2·day·atm, and the highest occupied molecular orbital energy level of the organic light-emitting material is greater than -5.7 eV.

3. The color conversion component as described in claim 1 or claim 2, wherein the (A) layer and the (B) layer are stacked in the order of (B) layer / (A) layer / (B) layer.

4. The color conversion member as claimed in claim 1 or claim 2, wherein the oxygen permeability of the (B) layer is less than 0.5 cc / m2·day·atm.

5. The color conversion component as claimed in claim 1, wherein the organic light-emitting material is a compound comprising two or more partial structures represented by the general formula (1).

6. The color conversion component as claimed in claim 1 or claim 2, wherein the organic light-emitting material comprises a compound represented by general formula (2) or general formula (3), wherein in general formula (2) or general formula (3), rings Za, Zb and Zc are independently substituted or unsubstituted rings forming aryl rings with 6 to 30 carbon atoms, or substituted or unsubstituted rings forming heteroaryl rings with 6 to 30 carbon atoms; Z1 and Z2 are independently oxygen atoms, NRa (nitrogen atoms having substituent Ra) or sulfur atoms; when Z1 is NRa, substituent Ra may bond with rings Za or Zb to form a ring; when Z2 is NRa, substituent Ra may bond with rings Za or Zc to form a ring; E is a boron atom, a phosphorus atom, SiRa (silicon atoms having substituent Ra) or P=O; E1 and E2 are independently oxygen atoms, phosphorus atoms, SiRa (silicon atoms having substituent Ra) or P=O; E1 and E2 are independently oxygen atoms, phosphorus atoms, SiRa (silicon atoms having substituent Ra) or P=O; E1 and E2 are independently oxygen atoms, nitrogen ... The substituent Ra is BRa (boron atom with substituent Ra), PRa (phosphorus atom with substituent Ra), SiRa2 (silicon atom with two substituent Ra), P(=O)Ra2 (phosphine oxide with two substituent Ra) or P(=S)Ra2 (phosphine sulfide with two substituent Ra), S(=O) or S(=O)2; when E1 is BRa, PRa, SiRa2, P(=O)Ra2 or P(=S)Ra2, the substituent Ra can bond with ring Za or ring Zb to form a ring; when E2 is BRa, PRa, SiRa2, P(=O)Ra2 or P(=S)Ra2, the substituent Ra... a can bond with cyclic Za or cyclic Zc to form a ring; the substituent Ra is independently selected from hydrogen, substituted or unsubstituted alkyl, substituted or unsubstituted cycloalkyl, substituted or unsubstituted heterocyclic, substituted or unsubstituted alkenyl, substituted or unsubstituted cycloalkenyl, substituted or unsubstituted alkynyl, substituted or unsubstituted aryl, substituted or unsubstituted heteroaryl, hydroxyl, thiol, substituted or unsubstituted alkoxy, substituted or unsubstituted alkylthio, substituted or unsubstituted aryl ether, substituted or unsubstituted arylthioether, halogen, cyano, aldehyde, substituted or unsubstituted carbonyl, substituted or unsubstituted The substituents Ra may be further substituted with the selected substituents.

7. The color conversion component as claimed in claim 6, wherein E in the general formula (2) is a boron atom, and E1 and E2 in the general formula (3) are BRa.

8. The color conversion member as claimed in claim 6, wherein the organic light-emitting material exhibits emission at a peak wavelength observed in a region of 500 nm to less than 580 nm by using excitation light in the range of wavelengths greater than 400 nm and less than 500 nm.

9. The color conversion component as claimed in claim 8, wherein the highest occupied molecular orbital energy level of the organic light-emitting material is above -5.7 eV.

10. The color conversion member as claimed in claim 1 or claim 2, wherein the organic light-emitting material exhibits emission at a peak wavelength observed in a region of 500 nm or more and less than 580 nm by using excitation light in the range of wavelengths greater than 400 nm and less than 500 nm.

11. The color conversion member as claimed in claim 1 or claim 2, wherein the (B) layer comprises an inorganic oxide layer or an inorganic nitride layer.

12. The color conversion member as claimed in claim 1 or claim 2, wherein the (B) layer comprises a cured layer of a resin composition comprising a polyol resin and a silicone compound having an alkoxy group and its hydrolysate.

13. A light source unit, characterized in that it comprises: A light source, and a color conversion component as described in any one of claims 1 to 12.

14. The light source unit as claimed in claim 13, wherein the light source is a light-emitting diode that emits light at a wavelength of 430 nm or more and 500 nm or less.

15. A display, characterized in that it comprises: The light source unit as described in claim 13 or claim 14.

16. A lighting device, characterized in that it comprises: The light source unit as described in claim 13 or claim 14.

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