JP7341946B2 - Fluorescence conversion medium - Google Patents

Description

The present invention relates to a fluorescence conversion medium, and more particularly to a green fluorescence conversion medium that can efficiently convert blue light into green light, and a red fluorescence conversion medium that can efficiently convert visible light from blue light to green light into red light. It is something.

Conventionally, as green fluorescent dyes, coumarin dyes, perylene dyes, naphthalimide dyes, and the like are known.

Methods of using devices using these dyes as wavelength conversion materials or dimming filters for display applications, light source applications, etc. have been proposed in Patent Documents 1 to 4 listed below, but the above applications have become increasingly diverse in recent years. Further studies are needed to address this issue.

On the other hand, rhodamine dyes, phenoxazone dyes, oxazine dyes, and the like are known as red fluorescent dyes, and phthalocyanine compounds, which are organic pigments, are also known as red fluorescent materials.

Methods for using devices using these red fluorescent materials as wavelength conversion materials or dimmer filters for display applications, light source applications, etc. are disclosed in the following Patent Documents 5 to 8, as well as the above-mentioned green fluorescent dyes. Although such methods have been proposed, further studies are desired to address the above-mentioned uses, which have become increasingly diverse in recent years.

Japanese Patent Application Publication No. 2006-104350 Special Publication No. 2014-519191 Japanese Patent Application Publication No. 2014-225415 Japanese Patent Application Publication No. 2017-138534 Japanese Patent Application Publication No. 10-306279 Japanese Patent Application Publication No. 2000-302994 Japanese Patent Application Publication No. 2003-264081 International Publication No. 2006/103907 pamphlet

The first object of the present invention is to provide a green fluorescence conversion medium that can efficiently convert blue light into green light. A second object of the present invention is to provide a red fluorescence conversion medium that can efficiently convert visible light ranging from blue light to green light into red light.

The first object of the present invention is achieved by a green fluorescence conversion medium containing a dye represented by the following general formula (1) and a binder that holds the dye. The second object of the present invention is achieved by a red fluorescence conversion medium containing a dye represented by the following general formula (1), at least one red fluorescent material, and a binder that holds them.

In general formula (1), R ₁ represents an aliphatic group, an aromatic group, or a heterocyclic group. R ₂ and R ₃ represent a hydrogen atom or an aliphatic group. L represents a methine group, and X and Y represent an electron-withdrawing group.

According to the present invention, it is possible to provide a green fluorescence conversion medium that can efficiently convert blue light into green light and a red fluorescence conversion medium that can efficiently convert visible light from blue light to green light into red light.

Light absorption characteristics of green fluorescence conversion medium 1 obtained in Example 1. Light absorption characteristics of green fluorescence conversion medium 7 obtained in Example 1.

The dye represented by general formula (1) of the present invention will be explained below. In general formula (1), R ₁ is an aliphatic group (for example, an alkyl group such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, an octyl group, a decyl group, a dodecyl group, an allyl group, If possible, alkenyl groups such as butenyl groups, alkynyl groups such as propargyl groups, aralkyl groups such as benzyl groups, phenethyl groups, phenylpropyl groups, phenylbutyl groups, 1-naphthylmethyl groups, 2-naphthylmethyl groups, etc. For example, the above aliphatic groups may have a branched structure), aromatic groups (e.g., phenyl group, tolyl group, naphthyl group, fluorene group, etc.), heterocyclic groups (e.g., indolyl group, pyridyl group, (furyl group, thienyl group, etc.). Moreover, R ₁ may further have a substituent well known in the art. Examples include amino groups, vinyl groups, alkoxy groups, aryloxy groups, alkylthio groups, arylthio groups, hydroxy groups, carboxyl groups, alkoxycarbonyl groups, aryloxycarbonyl groups, phosphonic acid groups, sulfo groups, halogen atoms, etc. There is. Note that these substituents may be a plurality or a combination of each. Among R ₁ described above, aromatic groups are preferred, and fluorene groups are particularly preferred. Also preferred is a phenyl group having an alkoxy group or an aryloxy group as a substituent.

R ₂ and R ₃ represent a hydrogen atom or an aliphatic group (synonymous with the aliphatic group of R ₁ ). Further, when R ₂ and R ₃ are both aliphatic groups, they may be connected to each other to form a cyclic structure. A preferable combination of R ₂ and R ₃ described above is one in which R ₂ and R ₃ are linked to each other to form a cyclopentane ring.

L represents a methine group. This methine group may be a conjugated methine group composed of multiple carbon atoms. Further, the methine group may have a substituent well known in the art, such as the one mentioned above that R ₁ may have. Among the methine groups mentioned above, preferred is an unsubstituted methine group having 1 carbon atom.

X and Y represent electron-withdrawing groups. Note that X and Y may be the same or different. Examples thereof include alkanoyl groups, cyano groups, carboxy groups, alkoxycarbonyl groups, aryloxycarbonyl groups, and the like. In addition, when X and Y are an alkanoyl group, an alkoxycarbonyl group, or an aryloxycarbonyl group, they may have a substituent well known in the art, such as the one mentioned above that _R1 may have. good. A preferred combination of X and Y mentioned above is one in which one is a cyano group and the other is a carboxy group or an alkoxycarbonyl group.

Next, the red fluorescent material used in the present invention will be explained. Examples of the red fluorescent material used in the present invention include known rhodamine dyes, phenoxazone dyes, oxazine dyes, phthalocyanine compounds of organic pigments, and dyes represented by the following general formula (2). . Among them, preferred are rhodamine dyes and dyes represented by general formula (2).

In general formula (2), R ₁₁ represents an aliphatic group, an aromatic group, or a heterocyclic group (each has the same meaning as R ₁ above). R ₁₂ and R ₁₃ represent a hydrogen atom or an aliphatic group (synonymous with R ₂ and R ₃ above). L ₁₁ represents a methine group (synonymous with L above). A represents any of the structures represented by the following general formulas (3) to (5).

In general formula (3), Z represents a nitrogen-containing heterocycle necessary to form a dye structure. Examples thereof include an oxazolidinone ring, a thiazolidinone ring, an imidazolidinone ring, and a pyrazolone ring, and a plurality of these may be connected in a dimer or more form. Further, the nitrogen-containing heterocycle may have a substituent well known in the art as described for _R1 . Among the nitrogen-containing heterocycles mentioned above, preferred are monomers and dimers of thiazolidinone rings.

Next, general formula (4) will be explained. Ar represents an aromatic group (synonymous with the aromatic group of _R1 ). Moreover, Ar may further have a substituent well known in the art. Examples include amino groups, acylamino groups, sulfonylamino groups, nitro groups, vinyl groups, alkoxy groups, aryloxy groups, alkylthio groups, arylthio groups, hydroxy groups, carboxy groups, alkoxycarbonyl groups, aryloxycarbonyl groups, Examples include phosphonic acid groups, sulfo groups, and halogen atoms. Note that these substituents may be a plurality or a combination of each. Among these, preferred are an acylamino group, a sulfonylamino group, a nitro group, and a halogen atom.

W represents an electron-withdrawing group. Examples thereof include alkanoyl groups, cyano groups, carboxy groups, alkoxycarbonyl groups, aryloxycarbonyl groups, and the like. Preferred among these is a cyano group.

Next, general formula (5) will be explained. V represents a substituent. Note that this substituent may not be present. Examples of substituents when present include alkyl groups, aryl groups, amino groups, acylamino groups, sulfonylamino groups, nitro groups, vinyl groups, alkoxy groups, aryloxy groups, alkylthio groups, arylthio groups, hydroxy groups, and carboxy groups. group, alkoxycarbonyl group, aryloxycarbonyl group, phosphonic acid group, sulfo group, halogen atom, etc. Note that these substituents may be a plurality or a combination of each.

Two or more of the red fluorescent materials described above may be used in combination. Among these, preferred combinations include rhodamine dyes and A in general formula (2) of the thiazolidinone ring monomer of general formula (3), or A of general formula (2) of general formula (4). be. In addition, A in the general formula (2) is a thiazolidinone ring dimer of the general formula (3), A in the general formula (2) is a thiazolidinone ring monomer of the general formula (3), or the general formula ( A combination in which A in 2) is of general formula (4) is also preferred. The above combination further improves the conversion intensity of blue light to green light into red fluorescence.

Specific examples of the dye represented by general formula (1) of the present invention are described below. Note that the present invention is not limited to these.

Next, specific examples of the dye represented by the general formula (2) of the present invention will be described. Note that, like the general formula (1), the present invention is not limited to these.

These compounds can be easily synthesized by referring to the synthesis methods described in, for example, JP-A-8-269345 and WO 2004/011555 pamphlet.

In the present invention, the dye represented by the general formula (1), or at least one of the dye and a red fluorescent material, is held in a binder, and more preferably the dye, or It is preferable to obtain a fluorescence conversion medium by retaining at least one of the dye and a red fluorescent material. This binder is not particularly limited, but examples include butyral resin, acrylic resin, epoxy resin, urethane resin, phenol resin, and modified cellulose.

The method of retaining the dye represented by the general formula (1), or at least one of the dye and the red fluorescent material in the binder is not particularly limited. The seeds may be dissolved in an organic solvent in which the binder is soluble, or the dye or at least one of the dye and a red fluorescent material may be made into fine particles by a dispersion method such as a bead mill, and then dispersed in the binder. good. Further, fine particles of the dye or at least one of the dye and a red fluorescent material may be dispersed in a binder solution.

The fluorescence conversion medium of the present invention is preferably supported by a support to form a fluorescence conversion film. The method for applying the above-mentioned fluorescent material-containing binder solution onto the support is not particularly limited, and includes bar coating, dip coating, spin coating, die coating, blade coating, gravure coating, curtain coating, and spray coating. Applying using a known method such as a coat method or a kiss coat method, or using a known method such as gravure printing, flexo printing, inkjet printing, screen printing, offset printing, gravure offset printing, dispenser printing, or pad printing. Examples include printing methods.

In addition, when using the dye represented by general formula (1) and at least one kind of red fluorescent emitting material together, they can be mixed and prepared as a single fluorescent material-containing binder solution, or they can be divided into separate parts for each fluorescent material. It may also be prepared as a binder solution containing a fluorescent material. Further, when a binder solution containing a fluorescent material is prepared separately for each fluorescent material, when applying these binder solutions onto a support, each solution may be sequentially applied by the above-mentioned method. Alternatively, the respective solutions may be mixed and applied simultaneously.

The supports include polyolefin resins such as polyethylene and polypropylene, vinyl chloride resins such as polyvinyl chloride and vinyl chloride copolymers, epoxy resins, polyarylates, polysulfones, polyethersulfones, polyimides, fluororesins, Various resin films such as phenoxy resin, triacetyl cellulose, polyethylene terephthalate, polyimide, polyphenylene sulfide, polyethylene naphthalate, polycarbonate, acrylic resin, cellophane, nylon, polystyrene resin, ABS resin, etc., glass such as quartz glass, alkali-free glass, etc. etc. The total light transmittance of the support is preferably 60% or more, particularly preferably 70% or more.

In addition, a fluorescent conversion medium is obtained by adding a dye represented by the general formula (1) or at least one of the dye and a red fluorescent material to the binder and resin film raw material resin described above, and then curing and molding the dye. You can also use it as

The fluorescence conversion medium of the present invention may further contain various additives, such as fillers, surfactants, thermal polymerization inhibitors, adhesion promoters, antioxidants, ultraviolet absorbers, anti-aggregation agents, etc., as necessary. May contain.

Hereinafter, the present invention will be explained in detail using Examples.

Example 1
A mixed solution with the following composition was treated in a paint shaker for 3 hours, filtered to remove beads, coated on a polyethylene terephthalate film with a thickness of 100 μm using bar coating so that the film thickness after drying was approximately 5 μm, and dried. It was later cut to obtain a green fluorescent conversion medium. The dyes used were the dyes of the present invention listed in Table 1 and the comparative dyes below.

<Mixed solution composition>
Butyral resin 1g
(Butvar (registered trademark) B-79 manufactured by Eastman Chemical Japan Co., Ltd.)
Pigment 20mg
2-butanone 15ml
0.3mm zirconia beads 20g

The fluorescence emission characteristics of each of the obtained green fluorescence conversion media were measured using a spectrofluorometer F-7000 (manufactured by Hitachi High-Tech Science Co., Ltd.) while changing the excitation wavelength from 400 to 500 nm. In the comparison of the green fluorescence intensity, the fluorescence intensity in the green region from 500 nm to 600 nm was compared based on the relative value when the value of the comparative dye C1 was set to 100. These results are shown in Table 1.

Furthermore, the light absorption characteristics of green fluorescence conversion medium 1 using D3 and green fluorescence conversion medium 7 using D13 were measured. The results are shown in FIGS. 1 and 2.

From the results in Table 1, the superiority of the present invention is clear. The superiority of the preferred embodiment of the present invention is also clear. Furthermore, from FIGS. 1 and 2, the green fluorescence conversion medium of the present invention has high absorbance in the blue light region and high transparency in the green light region, so it is possible to efficiently obtain green fluorescence with less loss due to self-trapping. it is obvious.

Example 2
A mixed solution with the following composition was treated in a paint shaker for 3 hours, filtered to remove beads, coated on a polyethylene terephthalate film with a thickness of 100 μm using bar coating so that the film thickness after drying was approximately 5 μm, and dried. It was later cut to obtain a red fluorescence conversion medium. The combinations of the dyes of the present invention used are as shown in Table 2. For comparison, each red fluorescent dye was used alone.

<Mixed solution composition>
Butyral resin 1g
(Butvar (registered trademark) B-79 manufactured by Eastman Chemical Japan Co., Ltd.)
Pigments (combinations and amounts listed in Table 2)
2-butanone 15ml
0.3mm zirconia beads 20g

The fluorescence emission characteristics of each of the obtained red fluorescence conversion media were measured using a spectrofluorometer F-7000 (manufactured by Hitachi High-Tech Science Co., Ltd.) while changing the excitation wavelength from 400 to 600 nm. In the comparison of the red fluorescence intensities, the fluorescence intensities in the red region from 600 nm to 700 nm were compared using relative values when the value of each red fluorescent dye alone was set as 100. These results are shown in Table 2.

From the results in Table 2, the superiority of the present invention is clear.

Example 3
Example 2 except that another red fluorescent dye of the present invention was added to the mixed solution composition of red fluorescence conversion media 6 to 9 and 21 to 24 in Example 2 in the combination and amount shown in Table 3. A red fluorescence conversion medium was obtained by performing the same operation as above. Comparison of fluorescence intensity was performed using the same evaluation method as in Example 2, and it was found that both red fluorescence conversion media were better than those of Example 2 and when the amount of red fluorescent dye added was increased in Example 2. The red fluorescence intensity was improved, and the effect was confirmed.

The fluorescence conversion medium of the present invention can be utilized for display materials, decorative materials, light control filters, wavelength conversion materials, and the like.

Claims (2)

A green fluorescence conversion medium containing a dye represented by the following general formula (1) and a binder for holding it.
(In general formula (1), R ₁ represents an aliphatic group, aromatic group, or heterocyclic group. R ₂ and R ₃ represent a hydrogen atom or an aliphatic group. L represents a methine group, X, Y represents an electron-withdrawing group.) A red fluorescence conversion medium containing the dye according to claim 1, at least one red fluorescent material, and a binder holding them.