JP2000230172A - Fluorescent member and light-emitting device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a fluorescent member having the function to convert blue- color light to red-color light in high efficiency. SOLUTION: This fluorescent member is characterized by having each at least one 1st fluorescent coloring matter with maximum absorption wavelengths of 350-500 nm and maximum light emission wavelengths of 530-595 nm and 2nd fluorescent coloring matter with maximum absorption wavelengths of 530-595 nm and maximum light emission wavelengths of 585-800 nm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluorescent member and a light emitting device using the same. More specifically, the present invention provides:
A fluorescent member that absorbs light and emits light having different wavelength characteristics, and emits light different from the emission wavelength characteristics of the light emitting member by combining the fluorescent member with a light emitting member such as an electroluminescent element or a light emitting diode. Light emitting device.

[0002]

2. Description of the Related Art A fluorescent material is excited to a higher energy state by light, and returns to an original energy state by emitting energy as light. In the so-called photoluminescence (PL) phenomenon, it is generally known that the emission wavelength characteristic has a longer wavelength than the excitation light wavelength characteristic. There are many reports of examples of using long wavelength conversion of light by such a PL phenomenon. For example, techniques for converting the emission color of an electroluminescent (EL) element or a light emitting diode (LED) are disclosed in JP-B-63-18319, JP-A-3-152897, and JP-A-9-738.
No. 07 publication. In the case of an EL element or LED, the emission wavelength characteristics can be adjusted to some extent by selecting a light emitting material, designing an element structure, and the like. However, it is difficult to satisfy the requirements of the three primary colors of blue, green, and red and the white display only by these methods. Therefore, an attempt has been made to realize a blue-green-red three-primary-color display or a white display by the PL phenomenon, that is, by combining a blue-light-emitting member with a light-emitting member that emits light having a green or red component.

[0003]

The emission spectrum characteristics of the fluorescent member largely depend on the fluorescent material itself in the fluorescent member. The emission intensity also depends on the excitation light wavelength and intensity, and this dependence is also derived from the sensitivity characteristics of the fluorescent material to the excitation light and is closely related to the absorption spectrum characteristics of the fluorescent material. Therefore, the excitation-emission characteristics of the fluorescent member,
That is, the wavelength conversion characteristics greatly depend on the fluorescent material in the fluorescent member, and in order to obtain specific wavelength conversion characteristics, it is essential to select a fluorescent material suitable for the specific wavelength conversion characteristics. For example, fluorescent materials suitable for converting blue light to green light are readily available. For example, JP-A-3-152897 describes that high-efficiency conversion can be performed relatively easily using a coumarin-based dye. On the other hand, conversion from blue light to red light has a large wavelength shift for a general fluorescent material, so that high-efficiency conversion has been difficult.

As an attempt to increase the conversion efficiency from blue light to red light, Japanese Patent Laid-Open No. 152897/1991 discloses high efficiency conversion by increasing the thickness of a film in which a fluorescent material is dispersed to several hundred μm. It is reported that it is possible. However, in such a method, restrictions on device design such as a shape and a cost are increased, which is not preferable.

Japanese Unexamined Patent Publications Nos. Hei 8-286033 and Hei 9-213478 disclose a fluorescent material that absorbs blue light and emits green light and a fluorescent material that absorbs blue light and green light and emits red light. A technique of converting blue light into red light or white light by using a fluorescent member is described. In this method, a fluorescent material that emits green light absorbs blue light, and a part of the excitation energy is converted to green light, and part of the energy is transferred and absorbed by the fluorescent material that emits red light to emit red light. . However, in this method, a certain amount of green component light is emitted together with the emission of the red component. Therefore, when blue light is converted into red light, the color purity of the obtained red light is reduced.

[0006] As described above, a technique for converting blue light into red light with high efficiency by using a fluorescent material is not yet sufficient.
An object of the present invention is to provide a fluorescent member that converts blue light into red light with high efficiency, and to provide a light emitting element that emits light containing a red component such as red light or white light using the fluorescent member.

[0007]

According to the present invention, the maximum absorption wavelength is 350 to 500 nm and the maximum emission wavelength is 530 to 500 nm.
A first fluorescent dye in the range of 595 nm, an absorption maximum wavelength of 530 to 595 nm, and an emission maximum wavelength of 585 to 80;
A second fluorescent dye in the range of 0 nm
There is provided a fluorescent member comprising:

Further, according to the present invention, the above-mentioned fluorescent member,
A light-emitting member that emits light containing at least a part or all of a wavelength range of 350 to 500 nm as a wavelength component is provided.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION In the fluorescent member of the present invention, it is considered that the first fluorescent dye and the second fluorescent dye share the roles of absorption of excitation light and emission of fluorescence, respectively. That is,
In the case where light having a blue peripheral wavelength as a main component is used as excitation light and light emission having a red peripheral wavelength as a main component is to be obtained, sufficient light is emitted because the second fluorescent dye alone has low sensitivity to excitation light in this wavelength range. No strength is obtained. However, in the presence of the first fluorescent dye having absorption in this excitation wavelength region, (1)
The excitation light excites the first fluorescent dye, a part of the energy is emitted as light from the first fluorescent dye, and a part of the energy excites the second fluorescent dye. Excitation of the fluorescent dye, a part of the energy moves to the second fluorescent dye with the energy unchanged, and excites the second fluorescent dye. It is considered that the second fluorescent dye is excited by the obtained energy, that is, the first fluorescent dye acts as a sensitizer for the second fluorescent dye, and the second fluorescent dye emits light. The sensitizing effect of the fluorescent member of the present invention due to the mixing of the fluorescent dye is described in Japanese Patent Application Laid-Open No. Hei 9-213478 described above. The fluorescent material absorbs blue light and emits green light, and absorbs blue light and green light. The same principle is used for a fluorescent member including a fluorescent material that emits red light.

However, as a result of the study, the present inventors have found that
When the first fluorescent dye and the second fluorescent dye have a maximum absorption wavelength and a maximum emission wavelength within a predetermined range, the efficiency of the emission of the second fluorescent dye is increased, and the emission of the first fluorescent dye is increased. Found to be suppressed.

This is considered to be due to the following reasons. That is, in transferring energy from the first fluorescent dye to the second fluorescent dye, direct energy transfer is more efficient than transfer through light emission of the first fluorescent dye. next,
When the first fluorescent dye and the second fluorescent dye having the absorption maximum wavelength and the emission maximum wavelength in the above-mentioned predetermined ranges are used, the ratio of direct transfer of energy is higher than transfer through light emission. As a result, it is considered that the luminous efficiency of the second fluorescent dye is increased.

Here, in the case of the configuration described in JP-A-9-213478, since the difference between the absorption and emission wavelength characteristics of the two fluorescent materials is larger than that of the present invention, light emission from the fluorescent material that emits green light is performed. The color purity decreases with some degree.
Further, the efficiency of the emitted red light with respect to the blue light does not increase. On the other hand, according to the configuration of the present invention, for example, by adjusting the dye concentration, the emission from the first fluorescent dye can be sufficiently reduced, and the emission of the second fluorescent dye with respect to the excitation light can be achieved. It is possible to increase the efficiency.

Further, in Japanese Patent Application Laid-Open No. Hei 9-213478, the absorption color and the emission color are limited to blue, green and red. However, for example, when an organic compound is used as a fluorescent material, it tends to have a wavelength characteristic with a wide half-value width, and thus emits whitish light or light of an intermediate color. Therefore, since there are few fluorescent materials that emit purely green or red light, the available fluorescent materials are limited. On the other hand, the fluorescent member of the present invention
Since any fluorescent dye can be used as long as it has a maximum wavelength of light emission or absorption within a predetermined range, there are a great many choices of fluorescent dyes that can be used.

Hereinafter, the fluorescent member of the present invention will be described in detail. The fluorescent member of the present invention has an absorption maximum wavelength of 350 to 500.
a first fluorescent dye having an emission maximum wavelength in the range of 530 to 595 nm (yellow green to orange) and an absorption maximum wavelength of 530 to 595 nm (yellow green to orange). And the emission maximum wavelength is 585 to 8
Any form may be used as long as at least one second fluorescent dye in the range of 00 nm (orange to near infrared) is included. Here, the color names described in parentheses after each wavelength range are the color names of monochromatic light of each wavelength.
Further, these wavelength ranges are the ranges of the maximum wavelengths of absorption and emission, and any absorption color or emission color may be used.

It is desirable that the first fluorescent dye and the second fluorescent dye are selected from fluorescent dyes having a difference in emission maximum wavelength of 60 nm or less. Further, as the emission maximum wavelength of the first fluorescent dye and the absorption maximum wavelength of the second fluorescent dye are closer to each other, energy transfer that does not cause light emission is more likely to occur, so that the difference between the two wavelengths is preferably as small as possible. In particular,
The difference is desirably 30 nm or less.

The first fluorescent dye has an absorption maximum wavelength in the range of 350 to 500 nm and an emission maximum wavelength of 53 to 500 nm.
Any fluorescent dye, whether organic or inorganic, can be used within a range of 0 to 595 nm. However, the difference between the emission maximum wavelengths of the first fluorescent dye and the second fluorescent dye is small, and the excitation light is In order to increase the wavelength shift between the wavelength characteristic of the second fluorescent dye and the emission wavelength characteristic of the second fluorescent dye, the first fluorescent dye is preferably a material having a large wavelength shift in absorption and emission. As the first fluorescent dye satisfying this condition,
2- [2- [4- (N, N-dimethylamino) phenyl] ethenyl] -4-dicyanomethylene-6-methyl-4H-pyran which is usually abbreviated as DCM, or JP-A-8-100
No. 173, which is particularly preferable because these DCMs and derivatives thereof have a large shift width between the absorption maximum wavelength and the emission maximum wavelength. Note that Japanese Patent Application Laid-Open
The DCM derivative described in Japanese Patent No. 100173 has the following general formula (I)

[0017]

Embedded image

Wherein Ar ¹ and Ar ² are an aryl group,
R ^{1 to} R ⁵ are a hydrogen atom or an alkyl group having 1 to 3 carbon atoms,
R ⁶ is represented by an alkyl group having 1 to 3 carbon atoms).

[0019]

Embedded image

[0020]

The second fluorescent dye may be any fluorescent dye, whether organic or inorganic, as long as it has an absorption maximum wavelength in the range of 530 to 595 nm and an emission maximum wavelength in the range of 585 to 800 nm. In particular, many organic fluorescent dyes having an emission wavelength around a red wavelength have a low conjugate double bond length and generally have low photostability, and many compounds are difficult to handle in an organic solvent system because of their ionic structure. However,
Perylene-based fluorescent dyes such as Lumogen FRed 300 (manufactured by BASF) have good light stability and solubility in organic solvents, and are particularly suitable as the second fluorescent dye.

In addition, DCM as the first fluorescent dye and Lumogen F Red 3 as the second fluorescent dye
The combination of 00 is particularly preferred. The reason is that the energy transfer between both dyes is good and that Lumo
This is because the light stability of gen F Red 300 is good, and accordingly, the light stability of DCM is significantly improved.

Further, the fluorescent member of the present invention may be constituted by only a first fluorescent dye and a second fluorescent dye such as a vapor-deposited film. In general, when the concentration of a fluorescent dye is increased to some extent, a phenomenon called concentration quenching occurs in which the absorbed excitation energy is deactivated without emitting light while being repeatedly transferred between dyes of the same kind. Therefore, it is desirable that the fluorescent member carry a fluorescent dye in a form of being dissolved or dispersed in some medium. Here, "dissolution" means a state in which the fluorescent dye is scattered in the medium in units of molecules, and "dispersion" means a state in which the fluorescent dye is scattered in the unit of a plurality of molecules in the medium. As described above, since the fluorescent member in which the fluorescent dye is dissolved or dispersed in the medium can adjust the concentration of each fluorescent dye, the emission from the second fluorescent dye is strong. It is also easy and preferable to adjust the light emission intensity from the first fluorescent dye with respect to the intensity.

As the medium, a medium that can be easily molded in accordance with the usage of the fluorescent member is preferable. Specifically, it can be selected from a solid such as a sintered body of a polymer compound or an inorganic compound, or a liquid such as water, alcohol or an organic solvent intended for use in a container. Among them, polymethyl methacrylate (PMMA), polycarbonate (PC), polyvinyl chloride (PVC), polyethylene terephthalate (P
Polymer materials such as ET) are particularly preferred because of their excellent moldability.

Also, the fluorescent member of the present invention has at least 3
Any fluorescent member may be used as long as it emits light containing a part or all of the wavelength range of 585 to 800 nm as a wavelength component by absorbing excitation light containing a part or all of the wavelength range of 50 to 500 nm as a wavelength component. Therefore, by appropriately selecting the optical path length, the structure, and the like, a fluorescent member that can take out the excitation light or its absorption residue and the emission of the first fluorescent dye or a fluorescent member that cannot take out the excitation light may be used. Next, a light emitting device using the fluorescent member of the present invention will be described in detail.

The light emitting device of the present invention has a thickness of 350 to 500 nm.
Any form may be used as long as the light emitting member that emits light containing a part or the whole of the wavelength range as a wavelength component is combined with the above-described fluorescent member of the present invention. Any light-emitting member may be used as long as it emits light in the above wavelength range. In particular, a light-emitting member whose light emission is controlled by electric energy such as an electric field or a current is preferable, and among them, an organic EL element, an inorganic EL element, an LED, and the like are preferable.

The fluorescent member is preferably closer to the light emitting portion of the light emitting member because the loss of the excitation light is reduced. When the light-emitting member is an organic or inorganic EL element, the fluorescent member is, for example, in the form of a film.
It can be arranged at any position in the light extraction direction from the light emitting portion of the L element. When the size of the unit light emitting region capable of controlling the light emission of the EL element does not have a sufficient size compared to the thickness of the light extraction side substrate, for example, the EL element as a light emitting member has a fine matrix structure, In the case where the fluorescent member is also formed of a fine pattern corresponding to the fluorescent member, it is desirable to form the fluorescent member between the inner surface of the light extraction side substrate and the electrode layer. This is because the relative position between the light emitting member and the fluorescent member is shifted depending on the viewing direction when the fluorescent member is formed outside the light extraction substrate. On the other hand, when the relative position between the light emitting member and the fluorescent member due to the viewing angle does not cause a problem, that is, the size of the unit light emitting area in which light emission of the EL element can be controlled is smaller than the thickness of the light extraction side substrate. In a case where the size is sufficiently large, the fluorescent member can be formed on the outer surface of the light extraction side substrate, or the light extraction side substrate itself can be formed of the fluorescent member. In particular, since the formation on the outer surface of the light extraction side substrate does not affect the inside of the EL element, the degree of freedom in design such as selection of the film thickness of the fluorescent member and selection of the constituent material is high, which is preferable. When the light emitting member is an LED, the light emitting chip is formed so as to directly cover the light emitting chip, the mold resin itself is formed of a fluorescent member, or the fluorescent member is formed in a film shape on the outer surface of the mold resin. Is possible.

The light emitting member and the fluorescent member do not need to be in direct contact with each other. The fluorescent member may be formed in the shape of the light emitting surface of the light emitting element, and the light emitting member may be provided so that the entire surface can be illuminated. At this time, a functional member such as a film having a light diffusing function may be provided between the light emitting member and the fluorescent member so that the light emitted by the light emitting member has substantially uniform brightness on the surface of the fluorescent member. In addition, it is also possible to form a fluorescent member in the form of a film on a light guide plate light incident surface, a light emitting surface, and a scattering surface of a light guide plate type surface light emitting member using an LED as a light source, or to form the light guide plate itself with a fluorescent member. It is.

By combining the light emitting member and the fluorescent member as described above, the light emitting color can be easily adjusted even when it is difficult to adjust the light emitting color by the light emitting member itself. Further, even when it is difficult to prepare a large number of light emitting colors of the light emitting member from the viewpoint of manufacturing cost, a desired number of light emitting colors can be obtained. Here, the light emitted through the fluorescent member will be described.

When the light emitting member is disposed on the back side with respect to the light extraction direction of the fluorescent member, or when scattering or reflection occurs inside or on the surface of the fluorescent member, a part of the light emitted from the light emitting member is transferred to the fluorescent member. Can be released via However, since the light emitted at this time is the remaining part of the specific wavelength component absorbed by the dye or medium in the fluorescent member at a certain ratio,
In most cases, it is not the same color as the light emitted from the light emitting member. Conversely, by adjusting the concentration of the fluorescent dye and the optical path length, it is possible to absorb most of the light emitted from the light emitting member by the fluorescent member so as not to be emitted. Further, by devising the structure of the light emitting element such as the positional relationship between the light emitting member and the fluorescent member, it is possible to prevent the light emitted from the light emitting member from being emitted through the fluorescent member.

The emission intensity of the first and second fluorescent dyes emitted from the fluorescent member can be adjusted by adjusting the concentration of each fluorescent dye and the optical path length of the fluorescent member. In particular, it is also possible to adjust the emission from the first fluorescent dye so that it is hardly emitted.
In many cases, light emitted from the second fluorescent dye is emitted from the fluorescent member without being absorbed by the first fluorescent dye. However, a phenomenon called self-absorption occurs when the optical path length of the fluorescent member is long or the concentration of the dye is high, and the short wavelength side of the luminescent component is absorbed by the second fluorescent dye itself,
The remaining light is emitted. Light emitted from the first fluorescent dye is mainly absorbed by the second fluorescent dye or self-absorbed by the first fluorescent dye itself, and the remaining components are emitted from the fluorescent member.

Since the intensity of each of these light components emitted through the fluorescent member can be adjusted to some extent,
For example, a red light-emitting element can be obtained by emitting light only from the second fluorescent dye. Furthermore, it is also possible to mix each component using excitation light containing components in the blue and green regions to form a white light emitting element. In particular, when the light-emitting member is a blue organic EL element, a blue LED, or the like, the light-emitting component includes a spectrum in the green region to some extent as a light-emitting component. In this case, if the fluorescent member is selected from a member that mainly absorbs only in the blue region and the yellow region and emits red light, the green component of the light emitted from the light emitting member is hardly absorbed by the fluorescent member and passes through the fluorescent member. Released. By mixing the green component, the residual absorption of the blue component, and the red component from the fluorescent member, a light-emitting element that emits white light having three primary colors as components can be obtained. At this time, the green component of the light emitted from the light emitting member is emitted through the fluorescent member almost without being absorbed so much. Therefore, the ratio of the luminance of the light emitted through the fluorescent member to the light emission luminance of the light emitting member, The luminance conversion rate of the member can be high. The reason for this is that the green region of visible light has the highest sensitivity in terms of human luminosity characteristics and thus contributes significantly to luminance, whereas the blue and red components contribute little to luminance.

When it is desired to increase the ratio of light emitted from the light emitting member, light is directly transmitted from the light emitting member to the part of the unit light emitting region where light emission can be controlled, without using the fluorescent member at an arbitrary ratio. What is necessary is just to provide the part which can be released. By doing so, it is also possible to adjust the chromaticity of the entire unit light emitting region by mixing the light emission of the fluorescent member and the light emission of the light emitting member at an arbitrary ratio, for example, thereby obtaining a white light emitting element. It is possible. Next, the present invention will be described more specifically with reference to examples, but the present invention is not limited to these examples.

[0034]

EXAMPLES [Examples and Comparative Examples of Fluorescent Member] (Example 1) PMMA (molecular weight of about 38,000, ACRO
S Co., Ltd.) and DCM and Lumogen F Red 3
Is dissolved in ethylene glycol monoethyl ether, coated and baked on a glass substrate by a spin coating method, and a fluorescent member 1 made of a 10 μm-thick PMMA film containing 0.3% by weight of DCM and Lumogen F Red 300, respectively. It was created.

A blue LED (manufactured by Nichia Corporation) is irradiated with blue light as excitation light from the normal direction of the fluorescent member 1,
PL of the fluorescent member 1 emitted at an angle of 45 ° with respect to the normal
Instantaneous multi-photometry system MC manufactured by Otsuka Electronics Co., Ltd.
It measured using PD-2000. Lum to 608nm
Red light having a chromaticity of x = 0.64 and y = 0.36, having a light emission maximum due to light emission of Ogen F Red 300, was observed. The results are shown in FIG. Also used blue LE
The emission spectrum of D is shown in FIG.

(Comparative Example 1) Coumarin 7 instead of DCM
Except that the fluorescent member 2 was used.
It was created. Further, the PL spectrum of the fluorescent member 2 excited by blue light was measured in the same manner as in Example 1. 603n
m has a first emission maximum due to the emission of Lumogen F Red 300, and 490 nm has a second emission maximum due to the emission of coumarin 7; chromaticity is x = 0.53, y =
0.40 orange light was observed. The results are shown in FIG.

(Comparative Example 2) Lumogen F Red
A fluorescent member 3 was prepared in the same manner as in Example 1 except that 300 was not used. Further, the PL spectrum of the fluorescent member 3 excited by blue light was measured in the same manner as in Example 1. It has an emission maximum at 564 nm and has a chromaticity of x = 0.4.
8, yellow light of y = 0.51 was observed. FIG. 4 shows the results. The absorption spectrum of the fluorescent member 3 was measured using a U-3410 type auto-recording spectrophotometer manufactured by Hitachi, Ltd. The maximum absorption wavelength was 461 nm. FIG. 5 shows the results.

(Comparative Example 3) Lumog instead of DCM
Comparative Example 2 except that en F Red 300 was used.
In the same manner as in the above, a fluorescent member 4 was prepared. Example 1
The PL spectrum of the fluorescent member 4 excited by blue light was measured in the same manner as described above. Red light having an emission maximum at 602 nm and chromaticity of x = 0.61 and y = 0.36 was observed. FIG. 6 shows the results. When the absorption spectrum of the fluorescent member 4 was measured in the same manner as in Comparative Example 2, the maximum absorption wavelength was 573 nm. FIG. 7 shows the results.

(Comparative Example 4) Coumarin 7 instead of DCM
Except that the fluorescent member 5 was used.
It was created. The PL spectrum of the fluorescent member 5 excited by blue light was measured in the same manner as in Example 1. 490n
m has emission maximum, chromaticity is x = 0.19, y = 0.5
One green light was observed. FIG. 8 shows the results. When the absorption spectrum of the fluorescent member 5 was measured in the same manner as in Comparative Example 2, the maximum absorption wavelength was 435 nm. FIG. 9 shows the results. The relative luminance values of the PL emission of the fluorescent members 1 to 5 in the above Example 1 and Comparative Examples 1 to 4 are 51
5, 460, 521, 100, and 705, and although the red light has low visibility, the fluorescent member 1 in Example 1 exhibited sufficiently high luminance.

Further, Lumogen F of the fluorescent member 1 is used.
The emission maximum intensity derived from the emission of Red 300 is Lu
The emission maximum intensity was about 5.9 times the maximum emission intensity of the fluorescent member 4 containing mogen F Red 300 alone. Further, the maximum emission intensity was about 1.2 times the maximum intensity of green emission of coumarin 7 of the fluorescent member 5. This result indicates that the coumarin-based dyes have already obtained practical wavelength conversion characteristics.
As in the case of green wavelength conversion, it means that sufficiently practical blue / red wavelength conversion characteristics were obtained. Furthermore, the fluorescent member 1
Has almost no wavelength component derived from the emission of DCM. Therefore, when used as red light, chromaticity correction using a color filter or the like is practically unnecessary. Further, the fluorescent dye DCM and Lumogen F Red 300 used for the fluorescent member 1 were compared with Comparative Examples 2 and 3.
From the results, it is suggested that the difference between the maximum emission wavelength and the maximum absorption wavelength is 38 nm, and the difference between the maximum emission wavelength and the maximum absorption wavelength is 9 nm, which is a very preferable combination.

On the other hand, in the fluorescent member 2 of Comparative Example 1, Lumo was used.
The emission maximum intensity derived from the emission of gen F Red 300 is about 3.4 times the emission maximum intensity of the fluorescent member 4 containing Lumogen F Red 300 alone, and the sensitizing effect of coumarin 7 is recognized. However, the sensitizing effect is smaller than that of the case of the fluorescent member 1, and about 0.
As a result of including the green wavelength component derived from the emission of coumarin 7 at the maximum emission intensity of 3 times, the emission color became orange. The fluorescent dye coumarin 7 used for the fluorescent member 2 and Lumo
The results of Comparative Examples 3 and 4 also indicate that gen F Red 300 is a combination having a large difference between the maximum emission wavelength of 112 nm and a large difference between the maximum emission wavelength and the maximum absorption wavelength of 83 nm, and a small sensitizing effect. .

[Embodiment of Light Emitting Element] (Embodiment 2) PMMA (molecular weight of about 38,000, ACRO
S Co., Ltd.) and DCM and Lumogen F Red 3
Is dissolved in ethylene glycol monoethyl ether, coated and baked on a glass substrate by a spin coating method, and a fluorescent member 6 composed of a 50 μm-thick PMMA film containing 0.3% by weight of DCM and Lumogen F Red 300, respectively. It was created. Further, a blue-color light emitting member 1 was obtained by superposing a blue color filter on a blue-green light emitting dispersion type EL device manufactured by Toshiba Corporation, and a fluorescent member 6 was further superposed thereon to obtain a light emitting device 1.

The emission spectrum of the light-emitting device 1 was measured using an instantaneous multi-photometry system MCPD-2000 manufactured by Otsuka Electronics Co., Ltd. Chromaticity x = maximum emission at 603 nm
A red light of 0.59, y = 0.39 was observed. FIG. 10 shows the results, and FIG. 11 shows the emission spectrum of the light-emitting member 2 measured in the same manner. Further, the light emission luminance of the light emitting member 1 is 100
The emission luminance of the light-emitting element 2 at cd / m ² was 77 cd / m ^2.
m ² .

Example 3 PMMA (molecular weight: about 3800)
0, ACROS) and DCM and Lumogen F
Red 300 is dissolved in ethylene glycol monoethyl ether, applied and baked on a glass substrate by a spin coating method, and then DCM and LumogenF Red are applied.
A fluorescent member 7 made of a 12 μm-thick PMMA film containing 0.3% by weight of each 300 was prepared. In addition, indium-tin oxide (ITO) having a thickness of 140 nm, copper phthalocyanine having a thickness of 5 nm, and
N, N'-diphenyl-N, N'-bis (1-naphthyl) -1,1'-biphenyl-4,4'-diamine with a thickness of 0.15% by weight and a perylene added thickness of 25 nm
Of bis (2-methyl-8-quinolinolato) (4-phenylphenolato) aluminum (III), tris (8-quinolinolato) aluminum (III) having a thickness of 40 nm, and aluminum having a thickness of 160 nm are laminated in this order. The resulting blue light emitting organic EL element was used as a light emitting member 2. The light emitting element 2 was obtained by superposing the fluorescent member 7 on the light emitting surface of the light emitting member 2.

The emission spectrum of the light-emitting device 2 was measured in the same manner as in Example 2. 602 nm, 521 nm, 4
White light having chromaticity x = 0.33 and Y = 0.37 having four emission maxima at 85 nm and 453 nm was observed. FIG. 12 shows the results, and FIG. 13 shows the emission spectrum of the light-emitting member 2 measured in the same manner. The light emission luminance of the light emitting member 3 is 1
The emission luminance of the light emitting element ^{2 at} the time of 00 cd / m ² is 74 c
d / m ² .

Example 4 PMMA (molecular weight: about 3800)
0, ACROS) and DCM and Lumogen F
Red 300 is dissolved in ethylene glycol monoethyl ether, applied and baked on a glass substrate by a spin coating method, and 0.3% by weight of DCM and Lumage are added.
Film thickness 3 containing 0.2% by weight of nF Red 300
A fluorescent member 8 made of a 5 μm PMMA film was formed. A light emitting member 3 emitting blue surface light by combining a blue LED manufactured by Nichia Corporation and a light guide plate arranged at a pitch of about 5 mm.
And The fluorescent member 8 was overlapped on the light emitting surface of the light emitting member 3 to obtain the light emitting element 3.

The emission spectrum of the light emitting device 3 was measured in the same manner as in Example 2. Chromaticity x = 0.4 with three emission maxima at 603 nm, 535 nm and 423 nm
3, yellow light of y = 0.42 was observed. FIG. 14 shows the results.
Shown in Further, the light emission luminance of the light emitting member 3 is 100 cd / m.
The light emission luminance of the light emitting element 3 at the time of ² was 41 cd / m ² .

(Example 5) A fluorescent member 9 having an opening provided by a dry etching method was formed on the fluorescent member 8 prepared in Example 4 such that one opening of 100 μm square was formed per 400 μm square surface area. The light emitting element 4 was obtained by superposing the fluorescent member 9 on the light emitting surface of the light emitting member 3. The emission spectrum of the light emitting device 4 was measured in the same manner as in Example 2. 603
White light with chromaticity x = 0.34 and y = 0.33 having three emission maxima of 535 nm and 431 nm was observed. FIG. 15 shows the results. The light emission luminance of the light emitting element 4 when the light emission luminance of the light emitting member 3 was 100 cd / m ² was 45 cd / m ² .

According to the above Examples and Comparative Examples, a fluorescent member that converts blue light into red light with high efficiency according to the present invention and a light emitting element that emits white light consisting of the three primary colors of red light and red, green, and blue using the fluorescent member are provided. It was confirmed that it could be created.

In the above embodiment, the light emission color of the light emitting element is limited to red light, white light, and yellow light. However, any light emission color including a red wavelength component may be used. I don't care. In addition, it is of course possible to obtain a white or multicolor light emitting device with higher luminance by using the blue / green wavelength conversion material together.

[0051]

As described above, the fluorescent member of the present invention is capable of converting light having a peripheral wavelength of blue into light having a peripheral wavelength of red with high efficiency, and is combined with a light emitting member containing a wavelength component around blue. With the light emitting device of the present invention, it is possible to obtain a luminescent color including a wavelength component around red such as red and white. When the fluorescent member and the light emitting element of the present invention are used, even when it is difficult to adjust the color of the light emitted by the light emitting member itself, or when it is not possible to prepare a large number of light emitting colors of the light emitting member from the viewpoint of manufacturing cost, etc. The emission color can be easily adjusted. Further, if the fluorescent member of the present invention and the blue / green wavelength conversion fluorescent member are processed into a fine multicolor pattern, a fine multicolor light emitting element can be realized even when the light emitting member itself cannot be processed into a fine pattern. Becomes possible.

[Brief description of the drawings]

FIG. 1 is a PL spectrum of a fluorescent member 1 described in Example 1.

FIG. 2 is an emission spectrum of the blue LED described in Example 1.

FIG. 3 is a PL spectrum of the fluorescent member 2 described in Comparative Example 1.

FIG. 4 is a PL spectrum of the fluorescent member 3 described in Comparative Example 2.

FIG. 5 is an absorption spectrum of the fluorescent member 3 described in Comparative Example 2.

FIG. 6 is a PL spectrum of the fluorescent member 4 described in Comparative Example 3.

FIG. 7 is an absorption spectrum of the fluorescent member 4 described in Comparative Example 3.

FIG. 8 is a PL spectrum of the fluorescent member 5 described in Comparative Example 4.

FIG. 9 is an absorption spectrum of the fluorescent member 5 described in Comparative Example 4.

FIG. 10 is an emission spectrum of the light-emitting element 1 described in Example 2.

FIG. 11 is an emission spectrum of the light emitting member 2 described in Example 2.

FIG. 12 shows an emission spectrum of the light-emitting element 2 described in Example 3.

FIG. 13 is an emission spectrum of the light emitting member 2 described in Example 3.

14 shows an emission spectrum of the light-emitting element 3 described in Example 4. FIG.

FIG. 15 is an emission spectrum of the light-emitting element 4 described in Example 5.

Claims (13)

[Claims] 1. A first fluorescent dye having an absorption maximum wavelength of 350 to 500 nm and an emission maximum wavelength of 530 to 595 nm, and a first fluorescent dye having an absorption maximum wavelength of 530 to 595 nm and an emission maximum wavelength of 585 to 800 nm. A fluorescent member comprising at least one second fluorescent dye. 2. The fluorescent member according to claim 1, wherein the difference between the emission maximum wavelength of the first fluorescent dye and the emission maximum wavelength of the second fluorescent dye is 60 nm or less. 3. The fluorescent member according to claim 1, wherein the difference between the emission maximum wavelength of the first fluorescent dye and the absorption maximum wavelength of the second fluorescent dye is 30 nm or less. 4. The method according to claim 1, wherein the first fluorescent dye is 2- [2- [4-
(N, N-dimethylamino) phenyl] ethenyl] -4
The fluorescent member according to any one of claims 1 to 3, which is -dicyanomethylene-6-methyl-4H-pyran or a derivative thereof. 5. The fluorescent member according to claim 1, wherein the second fluorescent dye is a perylene fluorescent dye. 6. The fluorescent member according to claim 1, wherein the fluorescent dye is carried in a solid or liquid form in a dissolved or dispersed form. 7. The fluorescent member according to claim 6, wherein the solid is a polymer material. 8. The method according to claim 1, wherein the fluorescent member is at least 350 to 500.
The light which absorbs light containing a part or all of the wavelength range of nm as a wavelength component, and emits light containing a part or all of the wavelength range of at least 585 to 800 nm as a wavelength component.
8. The fluorescent member according to any one of 7. 9. A light-emitting member, comprising: the fluorescent member according to claim 1; and a light-emitting member that emits light containing at least a part or all of a wavelength range of 350 to 500 nm as a wavelength component. Characteristic light emitting element. 10. The light emitting device according to claim 9, wherein the light emitted through the fluorescent member is red or white. 11. A light-emitting element has a unit light-emitting region capable of controlling light emission, and the unit light-emitting region emits light from a light-emitting member without a fluorescent member and a portion that emits light through a fluorescent member. The light emitting device according to claim 9, comprising a portion. 12. The unit light emitting device according to claim 11, wherein the unit light emitting region emits white light by mixing light emitted through the fluorescent member and light emitted from the light emitting member without passing through the fluorescent member. Light emitting element. 13. The light emitting device according to claim 9, wherein the light emitting member is an organic or inorganic electroluminescent device or a light emitting diode.