JP2838063B2 - Organic electroluminescence device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic electroluminescence device (hereinafter, may be abbreviated as an organic EL device), and more particularly, to a specific structure,
The present invention relates to an organic EL device that has a wide viewing angle, high color purity, and can realize a highly efficient multicolor light emitting device.

[0002]

2. Description of the Related Art In general, EL devices are self-luminous and have high visibility, and since they are completely solid devices, they have excellent impact resistance and are easy to handle. Its use has attracted attention. EL devices include an inorganic EL device using an inorganic compound as a light-emitting material and an organic EL device using an organic compound. Among these, the organic EL device can be used in a practical manner because the applied voltage can be significantly reduced. Chemical research is being actively conducted. The structure of the organic EL device is based on the structure of anode / light-emitting layer / cathode and provided with a hole injection / transport layer or an electron injection / transport layer as appropriate, for example, anode / hole injection / transport layer / light-emitting layer. / Anode / Hole Injection / Transport Layer / Emitting Layer / Electron Injection / Transport Layer / Cathode etc. are known. The hole injecting and transporting layer has a function of transmitting holes injected from the anode to the light emitting layer, and the electron injecting and transporting layer has a function of transmitting electrons injected from the cathode to the light emitting layer. I have. By interposing the hole injection transport layer between the light emitting layer and the anode, many holes are injected into the light emitting layer at a lower electric field, and further injected into the light emitting layer from the cathode or the electron injection transport layer. It is known that the emitted electrons are accumulated at the interface between the hole injection / transport layer and the light emitting layer because the hole injection / transport layer does not transport the electrons, and the luminous efficiency is increased. In order to make such an organic EL device a multicolor light emitting device, for example, (1) blue light emission is converted to green or red by fluorescence conversion,
Fluorescence conversion method for multicolor emission (Japanese Patent Application Laid-Open Nos. 3-15297 and 5-258860), (2) White light emission is converted into red, green, and blue by a color filter to obtain multicolor light emission. White color filter method [“Semic
ond. Sci. Technol. "Vol. 6, 305
, Pp. 323 (1991)], and (3) a microresonator method for realizing multicolor light emission by realizing red, green, and blue from light emission including white or various colors by using a microresonator is known. I have.

However, in the above method (1), although red, green, and blue can be satisfactorily realized, the conversion efficiency to red is not sufficient, and it is required to increase the conversion efficiency. In the method (2), high-luminance white light emission is required in order to obtain high-luminance red, green, and blue light. However, organic EL elements that emit high-luminance white light have not been found. The fact is that it has not been done. Further, the method (3) has a disadvantage that the viewing angle is narrow. On the other hand, International Patent Publication No. 94-07344 discloses a microresonator element in which a transparent electrode, an organic layer, and a counter electrode are sequentially provided on a dielectric multilayer film. However, although this device has advantages such as good color purity of emission color, it has a drawback that the viewing angle is narrow, and improvement thereof has been demanded. Japanese Patent Application Laid-Open Nos. 6-283270 and 7-142171 also disclose similar devices, but these devices also have the same disadvantages as described above. Further, JP-A-6-275381
Japanese Patent Application Laid-Open Publication No. H11-216,086 discloses a multicolor light-emitting organic EL element which is similar to the above but has a plurality of elements having a microresonator configuration with two or more kinds of optical distances. However,
Even if a large number of elements, such as a display, are realized by this technique, there is a problem that the viewing angle is limited. Further, a technique using a high refractive index transparent electrode or the like without using a dielectric multilayer film as a reflection film is disclosed (Japanese Patent Application No. Hei 6-27853).
issue). However, in this technique, although the viewing angle does not matter, it is difficult to obtain multicolor light emission,
The color purity is not always sufficient.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an organic EL device having a wide viewing angle, a high color purity, and a highly efficient multicolor light emitting device under such circumstances. It is assumed that.

[0005]

The inventor of the present invention has conducted intensive studies to develop an organic EL device having the above-mentioned preferable properties. As a result, the present inventor has a pair of reflective electrodes sandwiching an organic layer, and has an organic EL device. An element provided with a fluorescence conversion film having a specific function outside the reflective electrode on the side from which light emitted from the layer is extracted, and an optical film thickness between the reflective interfaces defined by the pair of reflective electrodes Have been found to be suitable for that purpose. The present invention
It has been completed based on such knowledge.

That is, the present invention has a pair of reflective electrodes sandwiching an organic layer, and converts the color of the light to fluorescence outside the reflective electrode on the side from which light emitted from the organic layer is extracted. In the organic EL device provided with the film, the optical film thickness between the reflective interfaces defined by the pair of reflective electrodes is set to enhance the intensity of light of a specific wavelength out of the light emitted from the organic layer, and An object of the present invention is to provide an organic EL device characterized in that the film for fluorescence conversion has a function of absorbing the light of the specific wavelength and erasing its directionality to make it isotropic.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An organic EL device according to the present invention comprises a pair of reflective electrodes, an organic layer sandwiched between the pair of electrodes, and a reflective electrode on the side from which light emitted from the organic layer is extracted. And a film (hereinafter referred to as a “fluorescence conversion film”) provided outside of the device as an essential component. FIG.
FIG. 1 is a schematic cross-sectional view showing an example of the configuration of an organic EL device of the present invention.
3, an organic layer 4 and a reflective electrode II3 'are sequentially laminated. The reflective electrode used in the EL element of the present invention is an electrically conductive film having a function of reflecting light emitted from the organic layer, and usually has a reflectance of 10% or more. One of them has a reflectance of 50%
As described above, it is particularly preferable that the reflectance is 70% or more and the other reflectance is 25% or more from the viewpoint of the effect of the present invention. Examples of such a reflective electrode include the following (1) to (4).

(1) Metal electrode A material made of a metal that reflects light, for example, Au, Ag, A
1, Pt, Cu, Mn, Mg, Ca, Li, Yb, E
u, Sr, Ba, Na and the like, and an alloy formed by appropriately selecting two or more of these metals, specifically, Mg: A
g, Al: Li, Al: Ca, Mg: Li and the like. Among these metals or alloys, those having a work function of 4.0 eV or less are preferable as a cathode, while those having a work function of 4.5 eV or more are suitable as an anode. (2) Laminated reflective electrode composed of metal film / transparent electrode or transparent electrode / metal film Since the transparent electrode itself has low reflectance, the reflectance can be increased by laminating it with a metal film. As the transparent electrode, a conductive oxide is preferable, and in particular, ZnO: Al, I
TO (indium tin oxide), SnO ₂ : Sb, I
nZnO or the like is preferable. On the other hand, as the metal film, a film made of the metal or alloy described in the above (1) can be preferably mentioned. In the laminated reflective electrode, any of a transparent electrode and a metal film may be provided at a portion in contact with the organic layer.

(3) Dielectric film / transparent electrode or transparent electrode /
The laminated reflective electrode made of a dielectric film The transparent electrode itself has a low reflectivity as described above, so by laminating a dielectric film having a high refractive index or a low refractive index,
The reflectivity can be increased. Here, as the high refractive index dielectric film, a transparent oxide film or a transparent nitride film having a refractive index of 1.9 or more is preferable, and a sulfide film or a selenide compound is also preferable if it is transparent. preferable. Examples of such a high refractive index dielectric film include ZnO, ZrO ₂ , and HfO.
_{2, TiO 2, Si 3 N} 4, BN, GaN, GaIn
N, AlN, Al ₂ O ₃ , ZnS, ZnSe, ZnSS
Preferably, a film made of e or the like is used. Alternatively, a film formed by powdering these and dispersing them in a polymer may be used. On the other hand, a low refractive index dielectric film has a refractive index of 1.5.
Preferable examples include the following films made of transparent oxides and fluorides, films formed by making the oxides and fluorides into powder and dispersing them in a polymer, and fluorinated polymer films. Specifically, MgF ₂ , CaF ₂ , BaF
₂ , a film composed of NaAlF, SiOF, etc., a film formed by dispersing these compounds into a powder and dispersed in a polymer, or a film composed of fluorinated polyolefin, fluorinated polymethacrylate, fluorinated polyimide or the like is preferable.

(4) Laminated reflective electrode comprising dielectric multilayer / transparent electrode or dielectric multilayer / metal electrode The dielectric multilayer in the laminated reflective electrode has the high refractive index described in (3) above. The optical film thickness of the dielectric film and the dielectric film having a low refractive index is λ / 4 (λ is the wavelength of emitted light).
It is preferable that the layer is formed by alternately laminating a large number of times so that the reflectance is 50% or more. Further, as the transparent electrode, those described in the above (2) can be mentioned, and as the metal electrodes, those described in the above (1) can be mentioned.

In the present invention, it is particularly preferable that one of the pair of reflective electrodes includes a laminate of a high refractive index dielectric and a transparent electrode or a dielectric multilayer film. Such a reflective electrode can be manufactured by, for example, an evaporation method or a sputtering method. Examples of the vapor deposition method include a resistance heating method and an electron beam method, and examples of the sputtering method include a DC sputtering method, an ion beam sputtering method, and an ECR (electron cyclotron resonance) method. In the present invention, it is necessary to set the optical film thickness between the reflective interfaces defined by the pair of reflective electrodes so that the intensity of light of a specific wavelength out of the light emitted from the organic layer is enhanced. is there.
That is, the optical film thickness (nd) between the two reflective interfaces is set so as to satisfy the relationship of (I) (nd) × 4π / λ + φ = 2mπ (I). Here, λ indicates the wavelength of light to be enhanced. φ indicates the sum of phase changes provided by reflections occurring at two reflective interfaces. For example, when one reflective interface is provided by metal, it is known that φ contributes π to π. m is an integer of 1 to 10.

In the present invention, it is preferable to set the above-mentioned specific wavelength, ie, λ, in the blue region of 420 to 490 nm. The reflective interface is an interface between the reflective electrode layer and the organic layer or a surface of the reflective electrode layer that is not in contact with the organic layer, and corresponds to the reflective electrode modes (1) to (4).
There is a reflective interface: (1) The interface between the metal electrode and the organic layer is a reflective interface. (2) In the structure of the transparent electrode / metal film / organic layer, the interface between the metal film and the organic layer becomes a reflective interface, while in the structure of metal film / transparent electrode / organic layer, the transparent electrode and the metal film Interface becomes a reflective interface.

(3) In the case of dielectric film / transparent electrode (a) In the structure of substrate / low refractive index dielectric film / transparent electrode / organic layer, the interface between the transparent electrode and the low refractive index dielectric film is It becomes a reflective interface. (A) In the configuration of the substrate / high-refractive-index dielectric film / transparent electrode / organic layer, the interface between the substrate and the high-refractive-index dielectric film or the interface between the transparent electrode and the high-refractive-index dielectric film is a reflective interface. Becomes (C) With respect to the interface having no substrate, the interface between the dielectric film and the transparent electrode or the interface of the dielectric film not in contact with the transparent electrode is a reflective interface. (3)-In the case of a transparent electrode / dielectric film Normally, a dielectric film cannot be used because it is not conductive, but can be used only in the case of conductivity. At this time, the interface between the dielectric film and the organic layer becomes a reflective interface. (4) In the configuration of the dielectric multilayer film / transparent electrode / organic layer, the interface between the dielectric multilayer film and the transparent electrode is a reflective interface. However, at this interface, it is necessary to accurately calculate and consider the phase change according to a known document [for example, “Appl. Phys. Lett.” Vol. 61, p. 2287 (1992)]. On the other hand, in the configuration of the dielectric multilayer film / metal electrode / organic layer, the interface between the metal electrode and the organic layer is a reflective interface.

In the above (1) to (4), in the case of a transparent electrode / organic layer configuration, if the refractive index of the transparent electrode is 1.8 or less, the interface between the transparent electrode and the organic layer is also reflective. Interface. As described above, there are always at least two reflective interfaces corresponding to a pair of electrodes. One of the features of the present invention is that the optical distance between the reflective interfaces is set to a specific value. Also, as shown in FIG. 2, when there are three reflective interfaces, (nd) ₁ , (nd) ₂ and (nd) 1
_There are three optical distances of three. In this case, (n
d) At least one of ( ₁ ), (nd) ₂ and (nd) ₃ should satisfy the relationship of the above formula (I). In addition,
When (nd) ₁ and (nd) ₂ satisfy the condition of the formula (I), the intensity of the emitted light at the wavelength λ is further increased, which is preferable. When there are more than three reflective interfaces, it can be considered in the same manner as in the case where there are three reflective interfaces.

The fluorescence conversion film in the EL device of the present invention is
In order to change the color of the light having the center wavelength λ emitted from the organic layer, the light is provided outside the reflective electrode on the side from which the emitted light is extracted, and is made of a phosphor. Materials used for the fluorescence conversion film include an inorganic fluorescent material and an organic fluorescent material. In particular, a material in which an organic fluorescent material is dispersed in a polymer is preferable. Examples of the organic fluorescent substance include coumarins, rhodamines, fluoresceins, cyanines,
Porphyrins, naphthalimides, perylenes, quinacridones and the like are preferred because of their high fluorescence quantum yield.
Particularly preferred are those having a fluorescence quantum yield of 0.3 or more when dispersed in a polymer binder. This organic fluorescent substance may be used alone or in combination of two or more. Also, as the polymer binder,
Transparent resins such as polymethacrylate, polycarbonate, polyvinyl chloride, polyimide, polyamic acid,
Polyolefin, polystyrene and the like can be preferably used.

This fluorescence conversion film also has a function of absorbing light having a central wavelength λ emitted from the organic layer, and erasing its directionality to make it isotropic. There is no particular limitation on the method for manufacturing such a fluorescence conversion film, and various methods can be used. For example, after dispersing an organic fluorescent substance in a polymer binder, this is cast, spin-coated, printed, bar-coated, extruded, roll-formed, pressed, sprayed, roll-coated, etc. Is used to form a film having a thickness of usually 500 to 50,000 nm, preferably 1,000 to 5,000 nm, to obtain a fluorescence conversion film. When an organic solvent is used in these film forming methods, examples of the organic solvent include dichloromethane; 1,2-dichloroethane;
Chloroform; acetone; cyclohexanone; toluene; benzene; xylene; N, N-dimethylformamide; dimethyl sulfoxide; 1,2-dimethoxyethane; diethylene glycol dimethyl ether; These solvents may be used alone or in combination of two or more.

In the EL device of the present invention, as described above, in one pair of reflective electrodes, the reflectance of one reflective electrode is 50% or more, particularly 70% or more, and the reflectance of the other reflective electrode is Although the rate is preferably 25% or more,
When increasing the selectivity of the wavelength λ, it is particularly advantageous that the reflectivity of the two reflective electrodes is 50% or more. The EL device of the present invention has the following two remarkable effects. (1) When the selectivity of the wavelength λ is given, the viewing angle dependency usually occurs. This is because, when observing at an angle from the front direction (perpendicular to the light emitting electrode surface), the intensity of the emitted light is significantly reduced, the selectivity of the wavelength λ is increased, and the color shift of the emitted light is caused. . On the other hand, in the EL device of the present invention, the emitted light is absorbed by the fluorescence conversion film, and the fluorescence is emitted again. Therefore, since the fluorescence is isotropic, there is no dependency on the viewing angle, and no color shift occurs due to the viewing angle. (2) In the EL device of the present invention, the conversion efficiency of the fluorescence conversion film can be increased. It has been found that the conversion efficiency of the fluorescent conversion film depends on the chromaticity, that is, there is a hue (chromaticity) at which the conversion efficiency is maximized. If the optical film thickness is set, the fluorescence conversion efficiency is maximized.

Here, the fluorescence conversion efficiency is defined by the following equation. Fluorescence conversion efficiency (%) = [Brightness after providing fluorescent conversion film /
Luminance before providing a fluorescence conversion film] × 100 The greater the fluorescence conversion efficiency, the higher the efficiency of the device, which is preferable. In the EL device of the present invention, at least two types of fluorescence conversion films are provided, one of which converts light in the blue region emitted from the organic layer into light in the green region, and another film is used as the other film. When the light in the blue region is set to be converted to light in the red region, various colors including green and red can be realized, and a multicolor light emitting element can be obtained.

FIG. 3 is a schematic cross-sectional view showing an example of the configuration of the multicolor light-emitting device of the present invention, in which a transparent layer 5, a green fluorescence conversion film 2G and a red fluorescence conversion film 2R are provided on a substrate 1.
On these, the reflective electrode I3, the organic layer 4, and the reflective electrode
II3 'shows the structure laminated | stacked sequentially. 3, when blue light is emitted from the organic layer 4, blue light is emitted from the transparent layer 5, green light is emitted from the green fluorescence conversion film 2G, red light is emitted from the red fluorescence conversion film 2R, and blue, green, Three red colors can be realized. Examples of the configuration of the organic EL device of the present invention include (1) substrate / fluorescent conversion film / reflective electrode I / organic layer / reflective electrode II, and (2) fluorescent conversion film / substrate / reflective electrode I / organic layer. / Reflective electrode II, (3) substrate / reflective electrode I / organic layer / reflective electrode II / fluorescence conversion film, etc.

In such a configuration, in order to extract the light emitted from the organic layer from the reflective electrode on the side where the fluorescence conversion film is provided, the light reflectance of this reflective electrode must be equal to that of the other reflective electrode. It is preferably smaller than the light reflectance of the conductive electrode. Also, if there is a substrate in the path for extracting light,
As this substrate, a substrate having optical transparency is used. As such a substrate, for example, a substrate made of glass, quartz, an organic polymer compound, or the like can be mentioned, and among them, a substrate having a refractive index of 1.6 or less is preferable. In the above configurations (1) and (3), a light-transmitting layer may be interposed between the fluorescence conversion film and the reflective electrode, if desired. Examples of the light-transmitting layer include a layer made of glass, an oxide, a transparent polymer, or the like.

In the organic EL device of the present invention, the organic layer portion sandwiched between the pair of reflective electrodes includes, for example, from the reflective electrode side of the anode to the reflective electrode side of the cathode. ) Hole transport region layer / light emitting layer (3) hole transport region layer / light emitting layer / electron injection layer (4) light emitting layer / electron injection layer (5) organic semiconductor layer / light emitting layer (6) organic semiconductor layer / electron Barrier layer / light-emitting layer (7) A structure of a hole transport region layer / light-emitting layer / adhesion improving layer. Among these configurations, the configurations of the hole transport region layer / light emitting layer, the hole transport region layer / light emitting layer / electron injection layer, and the hole transport region layer / light emitting layer / adhesion improving layer are preferable.

As the light emitting layer in the organic layer portion, as in the ordinary light emitting layer, (a) an injection function (when a voltage is applied,
Holes can be injected from the anode or the hole transport region layer, and electrons can be injected from the cathode or the electron injection layer. ),
(B) transport function (possible to move holes and electrons by the force of an electric field), (c) light-emitting function (providing a field for recombination of holes and electrons to emit light. ). The thickness of this layer is not particularly limited and can be appropriately determined depending on the situation, but is preferably 1 nm to 10 μm, and particularly preferably 5 nm to 5 μm.
μm. Here, a preferable light emitting material (host material)
Is represented by the general formula (II)

[0023]

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Wherein Y ^{1 to} Y ⁴ each represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an aralkyl group having 7 to 8 carbon atoms, a substituted or unsubstituted Aryl group having 6 to 18 carbon atoms, substituted or unsubstituted cyclohexyl group, substituted or unsubstituted carbon atom having 6 carbon atoms
Represents an aryloxy group having 1 to 18 carbon atoms and an alkoxy group having 1 to 6 carbon atoms. Here, the substituent is an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an aralkyl group having 7 to 8 carbon atoms, an aryloxy group having 6 to 18 carbon atoms, and an acyl having 1 to 6 carbon atoms. Group, acyloxy group having 1 to 6 carbon atoms, carboxyl group, styryl group, arylcarbonyl group having 6 to 20 carbon atoms, aryloxycarbonyl group having 6 to 20 carbon atoms, alkoxycarbonyl group having 1 to 6 carbon atoms, vinyl group , Anilinocarbonyl group, carbamoyl group, phenyl group, nitro group, hydroxyl group or halogen. These substituents may be single or plural. Also, Y ^{1 to} Y ⁴
May be the same or different from each other, and Y ¹ and Y ² and Y ³ and Y ⁴ may be bonded to a mutually-substituted group to form a substituted or unsubstituted saturated 5-membered ring or a substituted or unsubstituted 5-membered ring. It may form a substituted saturated 6-membered ring. Ar represents a substituted or unsubstituted arylene group having 6 to 20 carbon atoms, which may be monosubstituted or plurally substituted, and the bonding site may be any of ortho, para and meta. However, when Ar is an unsubstituted phenylene group, Y ^{1 to} Y ⁴ are
Each is selected from an alkoxy group having 1 to 6 carbon atoms, an aralkyl group having 7 to 8 carbon atoms, a substituted or unsubstituted naphthyl group, a biphenyl group, a cyclohexyl group, and an aryloxy group. General formula (III) AQB (III) wherein A and B each represent a monovalent group obtained by removing one hydrogen atom from the compound represented by the general formula (II). Show,
Q may be the same or different, and Q represents a divalent group that cuts a conjugated system. Or the general formula (IV)

[0025]

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[Wherein A¹Is a substituted or unsubstituted carbon
Arylene group of the formulas 6 to 20 or divalent aromatic heterocyclic group
Is shown. The bonding position may be ortho, meta or para
No. A ^TwoIs a substituted or unsubstituted ant having 6 to 20 carbon atoms
And a monovalent aromatic heterocyclic group. Y^FiveAnd Y
⁶Is a hydrogen atom, substituted or unsubstituted carbon number
6-20 aryl groups, cyclohexyl groups, monovalent aromatic
Group heterocyclic group, alkyl group having 1 to 10 carbon atoms, 7 carbon atoms
-20 aralkyl groups or C1-C10 alkoxy
Represents a group. Note that Y^Five, Y⁶May be the same or different
No. Here, when the substituent is a single substituent,
Group, an aryloxy group, an amino group or a substituent
Phenyl group. Y^FiveEach substituent is A
¹And a saturated or unsaturated 5- or 6-membered ring
May be formed, and similarly, Y⁶Each substituent is A^TwoAnd join
To form a saturated or unsaturated 5- or 6-membered ring
You may. Q represents a divalent group that cuts conjugation. 〕so
And the compounds represented. In addition, the general formula (III) and
Q in (IV) represents a divalent group that cuts a conjugated system, where
Conjugation is due to the nonpolarity of π electrons,
Includes unpaired or lone electron pairs.
As a specific example of Q,

[0027]

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And the like. The reason for using a divalent group that cuts a conjugated system in this way is that A
Alternatively, a compound forming B [that is, a compound represented by the general formula (II):
Is used alone as the organic EL device of the present invention, and EL obtained when the compound represented by the general formula (III) is used as the organic EL device of the present invention. This is because the emission color does not change. That is, it is to prevent the light-emitting layer using the compound represented by the general formula (II) or the general formula (III) from becoming shorter or longer. When connected by a divalent group that cuts the conjugated system, the glass transition temperature (Tg)
Can be confirmed to increase, a uniform pinhole-free microcrystalline or amorphous thin film can be obtained, and the uniformity of light emission is improved. Further, by bonding with a divalent group that cuts off a conjugated system, there is an advantage that EL emission does not increase in wavelength and synthesis or purification can be easily performed. Further, as preferred luminescent materials (host materials), 8-hydroxyquinoline,
Or a metal complex of a derivative thereof. Specifically, it is a metal chelate oxinoid compound containing a chelate of oxine (generally 8-quinolinol or 8-hydroxyquinoline). Such compounds exhibit a high level of performance and are easily formed into thin film form. Examples of oxinoid compounds satisfy the following structural formula.

[0029]

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[In the formula, Mt represents a metal, p is an integer of 1 to 3, and Z is independent of each other position. In order to complete at least two or more fused aromatic rings, Indicates required atoms. Here, the metal represented by Mt is a monovalent, divalent or trivalent metal, for example, an alkali metal such as lithium, sodium or potassium, an alkaline earth metal such as magnesium or calcium, or boron or aluminum. Is an earth metal. Any of the monovalent, divalent or trivalent metals known to be generally useful chelate compounds can be used. Z represents an atom in which at least one of two or more fused aromatic rings forms a heterocyclic ring composed of azole or azine. Here, if necessary, another different ring can be added to the fused aromatic ring. Further, in order to avoid adding a bulky molecule without improving the function, the number of atoms represented by Z is preferably 18 or less.

Further, specific examples of chelated oxinoid compounds include tris (8-quinolinol) aluminum, bis (8-quinolinol) magnesium, bis (benzo-8-quinolinol) zinc, bis (2-methyl-8-). Quinolylate) aluminum oxide, tris (8-quinolinol) indium, tris (5-methyl-8-quinolinol) aluminum, lithium 8-quinolinol, tris (5-chloro-8-quinolinol) gallium, bis (5-chloro-8- (Quinolinol) calcium, 5,7-dichloro-8-quinolinol aluminum, tris (5,7-dibromo-8-hydroxyquinolinol) aluminum and the like.

The light emitting layer can be formed by thinning the film by a known method such as a vapor deposition method, a spin coating method, a casting method, and an LB method. Is preferred. here,
The molecular deposition film is a thin film formed by depositing the compound from a gaseous state or a film formed by solidifying the compound from a molten state or a liquid state. Normally, this molecular deposited film can be distinguished from a thin film (molecule accumulation film) formed by the LB method by a difference in a cohesive structure and a higher-order structure and a functional difference resulting therefrom. Further, after the light emitting layer is dissolved in a solvent together with a binder such as a resin to form a solution,
This can be formed into a thin film by a spin coating method or the like. Examples of the material of the light emitting layer represented by the general formulas (II) to (IV) include the following compounds.

[0033]

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[0034]

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[0035]

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[0036]

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[0037]

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[0038]

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[0039]

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Next, the hole transport region layer is not always necessary for the device, but is preferably used for improving the light emitting performance. As the hole transport region layer, a material that transports holes to the light emitting layer with a lower electric field is preferable, and the mobility of holes is, for example, 10 ⁴ to 10 ⁶ V
/ Cm when applying an electric field of at least 10 ⁻⁶ cm ² / V ·
Seconds are even more preferred. In order to keep electrons in the light emitting layer, an electron barrier layer can be used between the light emitting layer and the reflective electrode of the anode. There is no particular limitation on such a hole transporting material as long as it has the above-mentioned preferable properties. Conventionally, in a photoconductive material, a material commonly used as a hole charge transporting material or a hole transporting material of an EL element is used. Any of known materials used for the transport region layer can be selected and used.

Examples of the hole transport material include triazole derivatives (see US Pat. No. 3,112,197) and the like.
Oxadiazole derivatives (see U.S. Pat. No. 3,189,447, etc.) and imidazole derivatives (JP-B-37-160)
No. 96, etc.), polyarylalkane derivatives (US Pat. Nos. 3,615,402 and 3,820,989,
3,542,544, JP-B-45-555, JP-B-51-10983, JP-A-51-93224, JP-A-55-17105, JP-A-56-4148, and JP-A-55-108667. 55-15695
Nos. 3 and 56-36656), pyrazoline derivatives and pyrazolone derivatives (US Pat. No. 3,180,72).
No. 9, No. 4,278,746, JP-A-55-88
Nos. 064 and 55-88065 and 49-1
JP-A-055537, JP-A-55-51086 and JP-A-56-51086
-80051, 56-88141, 5
JP-A-7-45545 and JP-A-54-112637,
And phenylenediamine derivatives (U.S. Pat. No. 3,615,404, JP-B-51).
Nos. -10105 and 46-3712, 47
JP-A-25-336, JP-A-54-53435,
JP-A-54-110536, JP-A-54-119925, etc.), arylamine derivatives (U.S. Pat.
7,450,3,180,703,3,240,597
No. 3,658,520, No. 4,232,103, No. 4,175,961, No. 4,012,376, JP-B-49-35702, JP-A-39-27577, and JP-A-55-144250. Gazette, 56-119
No. 132, 56-22437, West German Patent No.
1,110,518, etc.), amino-substituted chalcone derivatives (see U.S. Pat. No. 3,526,501, etc.), oxazole derivatives (described in U.S. Pat.
No. 46234), fluorenone derivatives (see Japanese Patent Application Laid-Open No. 54-110837, etc.), and hydrazone derivatives (US Pat. No. 3,717,462, Japanese Patent Application Laid-Open No. 54-59).
Nos. 143 and 55-52063 and 55-5
Nos. 2064 and 55-46760 and 55-
Nos. 85495, 57-11350, 57
And stilbene derivatives (JP-A-61-210363 and 61-228451).
Gazette, JP-A-61-14642, JP-A-61-7225
No. 5, JP-A-62-47646, JP-A-62-366.
Nos. 74, 62-10652 and 62-30
No. 255, No. 60-93445, No. 60-9
No. 4462, No. 60-174749, No. 60
1755052). Further, silazane derivatives (U.S. Pat. No. 4,950,950), polysilanes (JP-A-2-204996), aniline-based copolymers (JP-A-2-282263), and conductive high-molecular oligomers (JP-A No. 2-282263). ─2113
No. 99), especially thiophene-containing oligomers.

In the present invention, these compounds can be used as a hole transporting material. The following porphyrin compounds (those described in JP-A-63-2956965) and aromatic tertiary compounds Amine compounds and styrylamine compounds (US Pat. No. 4,127,412,
JP-A-53-27033, JP-A-54-58445, JP-A-54-149634, and JP-A-54-6429.
No. 9, No. 55-79450, No. 55-144
Nos. 250, 56-119132 and 61-
295558, 61-98353, 6
For example, it is preferable to use the aromatic tertiary amine compound. Representative examples of the porphyrin compound include porphine; 1,10,1
5,20-tetraphenyl-21H, 23H-porphine copper (II); 1,10,15,20-tetraphenyl-
21H, 23H-porphine zinc (II); 5,10,1
5,20-tetrakis (pentafluorophenyl) -2
1H, 23H-porphine; silicon phthalocyanine oxide; aluminum phthalocyanine chloride; phthalocyanine (metal-free); dilithium phthalocyanine; copper tetramethyl phthalocyanine; copper phthalocyanine; chromium phthalocyanine; zinc phthalocyanine; Methyl phthalocyanine and the like.

Representative examples of the aromatic tertiary amine compound and styrylamine compound include N, N, N ',
N'-tetraphenyl-4,4'-diaminophenyl,
N, N'-diphenyl-N, N'-di (3-methylphenyl) -4,4'-diaminobiphenyl, 2,2-bis (4-di-p-tolylaminophenyl) propane,
1-bis (4-di-p-tolylaminophenyl) cyclohexane, N, N, N ', N'-tetra-p-tolyl-
4,4'-diaminobiphenyl, 1,1-bis (4-di-p-tolylaminophenyl) -4-phenylcyclohexane, bis (4-dimethylamino-2-methylphenyl) phenylmethane, bis (4-di -P-tolylaminophenyl) phenylmethane, N, N'-diphenyl-
N, N'-di (4-methoxyphenyl) -4,4'-diaminobiphenyl, N, N, N ', N'-tetraphenyl-4,4'-diaminodiphenyl ether, 4,4'
-Bis (diphenylamino) quadriphenyl, N,
N, N-tri (p-tolyl) amine, 4- (di-p-tolylamino) -4 '-[4 (di-p-tolylamino) styryl] stilbene, 4-N, N-diphenylamino-
(2-diphenylvinyl) benzene, 3-methoxy-
4'-N, N-diphenylaminostilbenzene, N-
Examples include phenylcarbazole and aromatic dimethylidin compounds.

The hole transport region layer in the EL device of the present invention can be formed by forming the above compound by a known thin film method such as a vacuum evaporation method, a spin coating method, and an LB method. The thickness of the hole transport region layer is not particularly limited, but is usually 5 nm to 5 μm. The hole transport region layer may be composed of one or more layers of the above hole transport materials, or a hole transport region layer composed of a compound different from the hole transport region layer May be laminated. Further, as a material of the organic semiconductor layer, for example,

[0045]

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[0046]

Embedded image And the like. On the other hand, as a material of the electron barrier layer, for example,

[0047]

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[0048]

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[0049]

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And the like. The electron injection layer in the organic layer portion is made of an electron injection material and has a function of transmitting electrons injected from the cathode to the light emitting layer. There is no particular limitation on such an electron injecting material, and any one of conventionally known compounds can be selected and used. Preferred examples of the electron injection material include:

[0051]

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Nitro-substituted fluorenone derivatives, anthraquinodimethane derivatives described in JP-A-57-149259, JP-A-58-55450, JP-A-63-104061, etc., and “Polymer Preprints, Japan” Preprints, Japan) "Volume 37, Volume 3
No., page 681 (1988), etc.

[0053]

Embedded image Diphenylquinone derivatives such as,

[0054]

Embedded image Thiopyrandioxide derivatives such as

[0055]

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And heterocyclic tetracarboxylic anhydrides, such as naphthalene perylene, and carbodiimide. Further, it is described in “Journal of Applied Physics (J. Appl. Phys.)”, Vol. 27, p. 269 (1988) and the like.

[0057]

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A compound represented by the following formula:
No. 7, No. 61-143784, No. 61-148159
Fluorenylidenemethane derivatives described in JP-A-61-225151 and JP-A-61-2337.
No. 50, etc., anthraquinodimethane derivatives and anthrone derivatives, "Appl. Phys. Lett.", Vol. 55, No. 14,
The following oxadiazole derivatives described on page 89 (1989)

[0059]

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And the like. Further, a series of electron-transporting compounds described in JP-A-59-194393 are disclosed as materials for forming a light-emitting layer in the publication. It has been found that it can be used as a material for forming a layer. Especially

[0061]

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The compound represented by the following formula is preferred. The electron injection layer in the organic EL device of the present invention can be formed by forming the above compound by a known thinning method such as a vacuum evaporation method, a spin coating method, a casting method, and an LB method. The thickness of the electron injection layer is usually 5 nm to 5 μm.
m. The electron injection layer may be composed of one layer of one or more of these electron injection materials, or may be a layer in which an electron injection layer made of a compound different from the layer is laminated. .

Further, as the adhesion improving layer in the organic layer portion, a layer containing a material which is excellent in electron transferability and has high adhesion to the light emitting layer and the cathode is preferable. Such materials include, for example, metal complexes of 8-hydroxyquinoline or a derivative thereof, such as metal chelate oxinoid compounds including chelates of oxine (generally 8-quinolinol or 8-hydroxyquinoline). Specifically, tris (8-quinolinol) aluminum,
Tris (5,7-dichloro-8-quinolinol) aluminum, tris (5,7-dibromo-8-quinolinol) aluminum, tris (2-methyl-8-quinolinol) aluminum, and indium other than aluminum, magnesium, copper, Examples include gallium, tin, and lead complexes. In addition, oxadiazole derivatives are also suitable, and the oxadiazole derivatives include the compounds represented by the general formulas (V) and (VI).

[0064]

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[Wherein, Ar¹¹~ Ar¹⁴Replaces each
Or an unsubstituted aryl group; ¹¹And Ar¹²And A
r¹³And Ar¹⁴Are identical in each
Or different, Ar^FifteenIs a substituted or unsubstituted
Shows a reelene group. ] The electron transfer compound represented by
Can be Here, the aryl group is a phenyl group,
Phenyl, anthranyl, perylenyl, pyrenyl
And the like. As the arylene group, a phenylene group,
Naphthylene group, biphenylene group, anthracenylene group,
Examples include a peryleneylene group and a pyrenylene group. Ma
Further, as the substituent, an alkyl group having 1 to 10 carbon atoms, carbon
An alkoxy group or a cyano group of Formulas 1 to 10, and the like.
You. This electron transfer compound is preferably a thin film-forming compound.
No. Specific examples of the electron transfer compound include PB described above.
Including D

[0066]

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And the like. The adhesion improving layer in the organic EL device of the present invention is obtained by applying the above compound to, for example, a vacuum deposition method, a spin coating method, a casting method,
It can be formed by forming a film by a known thinning method such as the LB method. The thickness of the adhesion improving layer is usually from 5 nm to
It is selected in the range of 5 μm. The adhesion improving layer may be composed of one layer of one or two or more of these adhesive materials, or may be a layer obtained by laminating adhesion improving properties of a compound different from the layer. . Such an adhesion-improving layer is made of an electron-transporting compound having high adhesiveness, and of course plays a role as an electron injection layer. A technique for forming the organic layer into a single layer is known. In this technique, for example, a hole transport material, a light emitting material, an electron injection material, and the like are added to a binder such as polystyrene, polycarbonate, and polyvinyl carbazole. The mixture is homogenized, and a single layer of the mixture is formed between the reflective electrode of the anode and the reflective electrode of the cathode.
This monolayering technology is described in, for example,
991, Vol. 40, p. 3591. In the present invention, an organic layer portion according to this technique can also be used.

When holes are injected into the organic layer portion of the present invention from the outer layer portion, a charge injection auxiliary material is used to improve the charge injection property at the same electric field intensity and to inject a larger amount of charge. Is also good. The amount of the charge injection aid added to each layer of the organic layer is preferably 19% by weight or less, more preferably 0.05 to 9% by weight, based on the weight of each layer. Here, the description of the function and the like of the charge injection auxiliary material is described in International Application PCT / JP93.
/ 01198. Specific examples of the electron-donating stilbene derivative, distyrylarylene derivative, or tristyrylarylene derivative used as the charge injection aid include the following compounds.

[0069]

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[0070]

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[0071]

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[0072]

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[0073]

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[0074]

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[0075]

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[0076]

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[0077]

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In the EL device of the present invention, such an organic layer portion is advantageously selected so as to give emission light in the blue region. Next, a preferred manufacturing method of the EL device of the present invention will be described by taking, as an example, the structure of a fluorescence conversion film / substrate / reflective electrode I / hole transport region layer / light emitting layer / electron injection layer / reflective electrode II. First, a reflective electrode I (anode) having a desired thickness is formed on a suitable transparent substrate by a method such as vapor deposition or sputtering, and then each of a reflective electrode I (anode transport material), a luminescent material, and an electron injection material is formed. Form a thin film.

Examples of the method of thinning include a spin coating method, a casting method, and a vapor deposition method. A vacuum vapor deposition method is preferable because a uniform film is easily obtained and pinholes are hardly generated. . When this vapor deposition method is adopted for thinning, the vapor deposition conditions vary depending on the type of compound used, the target crystal structure of the molecular deposition film, the association structure, and the like.
Vacuum degree 10 ^-5 to 10 ^-8 Pa, deposition rate 0.01 to 50 nm
/ Sec, substrate temperature -50 to 300 ° C, film thickness 5 nm to 5
It is desirable to select an appropriate value in the range of μm. Next, after these layers are formed, a reflective electrode I (cathode) is formed on the
It is provided by, for example, a method such as vapor deposition or sputtering so that the film thickness is in the range of 50 to 200 nm, preferably 50 to 200 nm. Next, on the opposite surface of the transparent substrate, usually 500 to 500 by a spin coating method, a printing method, or the like.
The fluorescence conversion film is provided so as to have a thickness of 00 nm, preferably 1000 to 5000 nm.

When a DC voltage is applied to the EL device obtained in this way, when a voltage of about 5 to 40 V is applied with the anode being positive and the cathode being negative, light emission with high color purity can be observed. . Also, even if a voltage is applied with the opposite polarity, no current flows and no light emission occurs. Further, when an AC voltage is applied, light is emitted only when the anode is in the + state and the cathode is in the-state. The waveform of the applied alternating current may be arbitrary. The EL element of the present invention is characterized in that the directionality of light emitted from the organic layer is erased and isotropic, so that the viewing angle is extremely wide. If the directionality of the blue light remains, the reflectance of the reflective electrode in the blue light emitting portion may be reduced, or the transparent layer may have diffusivity. This diffusivity can be achieved, for example, by including white inorganic fine particles that diffuse light in the transparent layer, or by providing irregularities on the surface of the transparent layer. Furthermore, in the present invention, higher efficiency can be achieved as compared with a device provided with a conventional fluorescence conversion film, and a multicolor light emitting device having high efficiency can be realized.

[0081]

EXAMPLES Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. Comparative Example 1 Fabrication of Micro Resonator Element On a white plate glass having a refractive index of 1.54, the center λ of the emission light wavelength =
Assuming 460 nm, TiO ₂ /
A dielectric multilayer mirror made of SiO ₂ and having a thickness of 12800 nm [manufactured by Nippon Vacuum Optical Co., Ltd., refractive index of TiO ₂ 2.3, SiO ₂
Refractive index 1.47, reflectance 95%]. An InZnO film having a thickness of 100 nm was formed thereon by DC magnetron sputtering at a substrate temperature of 60 ° C. In addition, as a sputtering target, it consists of a mixture of indium oxide and zinc oxide, and In /
A sintered body having an (In + Zn) atomic ratio of 0.74 was used. As for sputtering conditions, a mixed gas of argon gas and oxygen gas (volume ratio: 1000: 2.8) in the vacuum chamber was used.
And the target applied voltage was 420 V at a vacuum pressure of 2 × 10 ⁻³ Torr. The film I thus formed
The nZnO film was a transparent conductive film and had a refractive index of 2.0.

Next, on this InZnO film, 68 nm of MTDATA was laminated as a hole injection layer by vacuum evaporation, and then 20 nm of NPD was laminated as a hole transport layer. Next, 40 nm of DPVBi was laminated as a light emitting layer. At this time, the light-emitting layer was formed using PAVBi as a dopant.
Co-evaporation was performed at the same time so that the weight% was mixed. Thereafter, an 8-hydroxyquinoline-aluminum complex (Alq) was laminated as an electron transport layer to a thickness of 20 nm, and finally a magnesium: silver mixed electrode was laminated to a thickness of 150 nm. This magnesium: silver mixed electrode was formed by a simultaneous vapor deposition method at a vapor deposition rate of magnesium of 1.7 nm / sec and a vapor deposition rate of silver of 0.1 nm / sec. Thus, the reflective electrode of the cathode composed of the magnesium: silver mixed electrode (reflectance: 85%) and the reflective electrode of the anode composed of the dielectric multilayer film (TiO ₂ / SiO ₂ ) / transparent electrode (InZnO) An organic EL device (micro-resonator device) having an organic layer sandwiched between them was obtained. In Table 1,
The thickness, refractive index, and optical thickness of each layer are shown.

[0083]

[Table 1]

The reflective interface in this EL element is composed of a dielectric multilayer film (TiO ₂ / SiO ₂ ) and a transparent electrode (InZn).
O) and the interface between the Alq film and the magnesium: silver mixed electrode, the optical film thickness between the two reflective interfaces is 34 + 67 + 34 + 115 + 200 = from Table 1.
It becomes 450 nm. The phase change in the magnesium: silver mixed electrode is π, and the phase change in the TiO ₂ / SiO ₂ dielectric multilayer is (effective optical film thickness) × 4π / λ. Therefore, equation (I) (nd) × 4π / λ + φ = 2mπ (I) is 450 × 4π / λ + 585 × 4π / λ + π = 2mπ
Satisfies λ = 460 nm and m = 5. next,
When a voltage of 7 V was applied to the device and a light emission test was performed, a front luminance of 600 cd / m ² was obtained at a current value of ² mA / cm ² . Further, as shown in FIG. 4, when the measurement was performed while changing the viewing angle by the angle θ, the front emission intensity was 1 /
The angle of 2 was 20 °, indicating that the viewing angle was extremely narrow. However, the CIE chromaticity coordinates measured from the front were (0.12, 0.13), and the color purity as blue was excellent. The peak wavelength of the EL light by spectroscopy is 4
It was 62 nm, which was as designed. In FIG. 4, 1 is a substrate, 4 is an organic layer, 6 is a dielectric multilayer film, 7 is an InZnO film, and 8 is an Mg: Ag mixed electrode.

[0085]

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Example 1 A device was prepared in the same manner as in Comparative Example 1, and coumarin 6 was coated on a surface of the glass substrate opposite to the surface on which the EL device was present at a concentration of 0.03 mol / kg with a polyvinyl chloride resin (molecular weight). 2000
An ink obtained by dissolving the dispersion in 0) in cyclohexanone was applied, and a green fluorescence conversion film having a thickness of 20,000 nm was provided. Next, when a voltage of 7 V was applied to the EL element provided with the green fluorescence conversion film to perform a light emission test, a yellowish green color having CIE chromaticity coordinates (0.28, 0.62) was obtained. It was confirmed that light emission occurred. The front luminance is 50 cd / m ² , and the current value is 2.0 to 2.1 mA / cm ²
Met. Further, in the same manner as in Comparative Example 1, the emission intensity was 1
When the angle of / 2 was measured, it was 65 °, and the viewing angle was significantly widened, confirming the remarkable effect of the present invention.

Comparative Example 2 An EL element provided with a green fluorescence conversion film was manufactured in the same manner as in Example 1, except that the dielectric multilayer film composed of TiO ₂ / SiO ₂ was not used. . Next, a light emission test was performed by applying a voltage of 7 V to the EL device, and it was confirmed that yellowish green light emission having CIE chromaticity coordinates (0.28, 0.63) was generated. The front luminance was 36 cd / m ² and the current value was 2.0 to 2.1 mA / cm ² . Comparing Example 1 and Comparative Example 2 with respect to the front luminance, it can be seen that Example 1 is considerably larger. This is because in Example 1, the conversion efficiency of the green fluorescence conversion film became maximum around a wavelength of 460 nm, and it was found that the device of the present invention could improve the conversion efficiency. As described above, in the present invention, at the wavelength at which the efficiency of the fluorescence conversion film is maximized, the emission light intensity of the microresonator element can be maximized, so that the conversion efficiency can be improved.

Example 2 An EL device was manufactured in the same manner as in Example 1, except that a red fluorescence conversion film was provided instead of the green fluorescence conversion film. In addition, the red fluorescence conversion film is made of a polyvinyl chloride resin (molecular weight 2) containing rhodamine-containing pigment at a concentration of 43% by weight.
(000) dispersed in cyclohexanone. Next, a voltage of 7
When a light emission test was performed by applying V, it was confirmed that red light emission of CIE chromaticity coordinates (0.60, 0.31) occurred. When the angle at which the luminous intensity became １ ／ was measured in the same manner as in Comparative Example 1, the angle was 68 °, and the viewing angle was significantly widened.

Example 3 A green fluorescence conversion film and a red fluorescence conversion film were patterned on the opposite surface of the device manufactured in the same manner as in Comparative Example 1 by screen printing using the inks prepared in Examples 1 and 2. did. Next, a light emission test was performed by applying a voltage of 7 V to the device. As a result, a green color conversion film was provided, a red fluorescence conversion film was provided, and a green color conversion film was not provided. Emission of red and blue light was observed.

[0090]

The organic EL device of the present invention can provide a multicolor light emitting device having a very wide viewing angle, high color purity, and high efficiency. For example, it can be used as an information display or a several character display device. It is preferably used.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an example of the configuration of an organic EL device of the present invention.

FIG. 2 is an explanatory diagram of an optical film thickness between reflective interfaces.

FIG. 3 is a schematic cross-sectional view illustrating an example of a configuration of a multicolor light emitting device of the present invention.

FIG. 4 is an explanatory diagram for obtaining a viewing angle of an EL element in Examples and Comparative Examples.

[Explanation of symbols]

 Reference Signs List 1 substrate 2 fluorescence conversion film 2G green fluorescence conversion film 2R red fluorescence conversion film 3 reflective electrode I 3 'reflective electrode II 4 organic layer 5 transparent layer 6 dielectric multilayer film 7 InZnO film 8 Mg: Ag mixed electrode

Claims (7)

(57) [Claims] 1. A light-emitting device, comprising: a pair of reflective electrodes sandwiching an organic layer; and a film for converting the color of the light to fluorescence outside the reflective electrode on the side from which light emitted from the organic layer is extracted. In the organic electroluminescence element, the optical film thickness between the reflective interfaces defined by the pair of reflective electrodes is set so as to enhance the intensity of light of a specific wavelength out of the light emitted from the organic layer, and the fluorescent light An organic electroluminescence device, wherein the film to be converted has a function of absorbing the light of the specific wavelength, erasing its directionality and isotropy. 2. A light having a specific wavelength of 420 to 490 nm.
2. The organic electroluminescence device according to claim 1, wherein the light is in the blue region. 3. The organic electroluminescence according to claim 1, wherein, in the pair of reflective electrodes, the reflectance of one reflective electrode is 50% or more, and the reflectance of the other reflective electrode is 25% or more. element. 4. The organic electroluminescent device according to claim 1, wherein the organic layer is selected to provide emission light in a blue region. 5. The organic electroluminescence device according to claim 1, wherein one of the pair of reflective electrodes is a laminate of a high refractive index dielectric and a transparent electrode. 6. The organic electroluminescence device according to claim 1, wherein one of the pair of reflective electrodes includes a dielectric multilayer film. 7. At least two kinds of films for performing fluorescence conversion are provided, one of which converts light in a blue region emitted from an organic layer into light in a green region, and the other film has another film. 2. The organic electroluminescent device according to claim 1, wherein the organic electroluminescent device is a multicolor light emitting device that converts light in a blue region into light in a red region.