WO2015004811A1

WO2015004811A1 - Organic el element and organic el lighting apparatus using same

Info

Publication number: WO2015004811A1
Application number: PCT/JP2013/069208
Authority: WO
Inventors: 裕紀若菜; 石原　慎吾; 素子原田
Original assignee: 株式会社日立製作所
Priority date: 2013-07-12
Filing date: 2013-07-12
Publication date: 2015-01-15
Also published as: JPWO2015004811A1

Abstract

Provided are: an organic EL element, wherein the film thickness of a low-refractive index layer disposed between a reflecting layer or a reflecting electrode and a light emitting layer is reduced, while maintaining the rate of propagation light of the organic EL element; and an organic EL lighting apparatus using the organic EL element. This organic EL element has a pair of electrodes, and an organic layer (102), which is disposed between the electrodes, and which includes a light emitting layer (203). One of the electrodes is formed by laminating, from the organic layer (102) side, a transparent electrode (103), a low-refractive index layer (104) having a lower refractive index than the light emitting layer (203), and a reflecting layer (105), and the refractive index of the low-refractive index layer (104) is equal to or lower than 1.4.

Description

Organic EL element and organic EL lighting device using the same

The present invention relates to an organic EL element and an organic EL lighting device using the same.

The organic EL lighting device is a lighting device using, as a pixel, an organic EL element characterized by self-emission with a thin film.

As a prior art of such an organic electroluminescent illuminating device, the bottom emission type illuminating device shown in FIG. 10 is known.

A lighting device L shown in FIG. 10 includes a pair of electrodes A and B, and an organic compound layer C disposed between the electrodes A and B (for example, a hole injection layer C1, a hole transport layer C2, and a light emitting layer C3). And the electron transport layer C4 and the electron injection layer C5 are formed to be stacked on each other).

By the way, in the conventional lighting device L shown in FIG. 10, of the energy generated from the organic EL element S in the attenuation mode (see FIG. 11) called evanescent mode (also referred to as surface plasmon mode), It is known that the rate decreases. For example, as shown in FIG. 12, when the position (light emitting position) of the light emitting layer C3 with respect to the reflective electrode B is 50 nm, about 20%, about 34%, about 4 depending on the external mode, the substrate mode and the thin film mode, respectively. %, That is, about 58% of the energy generated from the organic EL element S can be treated as propagation light, and can be taken out from the organic EL element S into the air, but about 42% of the energy generated from the organic EL element S by evanescent mode. It has been confirmed by the present inventors that% is lost in the organic EL element S. In such a conventional lighting device L, although the ratio of the propagation light can be increased by enlarging the light emission position, when the light emission position is enlarged as such, the distance between the reflective electrode B and the light emitting layer C3 is increased. Problems such as a rise in voltage and a rise in manufacturing cost may occur.

Patent Document 1 discloses a light emitting device for the purpose of improving the light emission efficiency and the color purity.

The light emitting device disclosed in Patent Document 1 includes an organic EL element having a pair of transparent electrodes and an organic compound layer including a light emitting layer disposed between the transparent electrodes, and a light extraction surface of the organic EL element. The transparent electrode on the opposite side to the organic compound layer has a refractive index higher than that of the organic compound layer, and the low refractive index layer and the reflective film have a refractive index lower than that of the organic compound layer on the side opposite to the light extraction surface of the organic EL element And an organic compound layer side in this order from the organic compound layer side, and a light extraction structure for extracting guided light is provided on the same plane as the light emitting layer.

JP, 2013-012378, A

According to the light emitting device disclosed in Patent Document 1, the guided light propagates in the light emitting device while being repeatedly reflected and is incident on the light extraction layer, and the guided light incident on the light extraction layer is reflected, scattered, diffracted, etc. By converting the propagation angle by means of this, part of the guided light can be extracted into the air.

However, in the light emitting device disclosed in Patent Document 1, the refractive index of the low refractive index layer is not defined. For example, in blue emission of the organic EL element, the film thickness of the low refractive index layer is 100 nm to 400 nm. Since the film thickness of the low refractive index layer is in the range of 300 nm to 400 nm in the green light emission and the film thickness of the low refractive index layer corresponding to the light emission position is relatively large, the reflective electrode and the light emitting layer Problems such as an increase in voltage during the period and an increase in manufacturing cost may remain.

The present invention has been made in view of the above problems, and the object of the present invention is to place the layer between the reflective layer or the reflective electrode and the light emitting layer while maintaining the ratio of the propagation light of the organic EL element. It is an object of the present invention to provide an organic EL element capable of reducing the film thickness of the low refractive index layer and an organic EL lighting device using the same.

In order to solve the problems described above, an organic EL device according to the present invention is an organic EL device having a pair of electrodes and an organic layer disposed between the electrodes and including a light emitting layer, wherein One is formed by laminating an electrode layer from the organic layer side and a low refractive index layer having a refractive index lower than that of the light emitting layer, and a reflective layer, and the low refractive index layer has a refractive index of 1.4 or less. It is characterized by

Another embodiment of the organic EL device according to the present invention is an organic EL device having a pair of electrodes and an organic layer disposed between the electrodes and including a light emitting layer, wherein one of the electrodes is A low refractive index layer having a refractive index lower than that of the light emitting layer from the organic layer side and to which conductivity is imparted and a reflective electrode layer are laminated and formed, and the low refractive index layer has a refractive index of 1.4 or less It is characterized by being.

Further, an organic EL lighting device according to the present invention is an organic EL lighting device including the organic EL element and a substrate on which the organic EL element is mounted and fixed, and the other of the organic EL element is provided on the substrate. It is characterized in that the electrodes are disposed to face each other.

Moreover, the other form of the organic electroluminescent illuminating device which concerns on this invention is an organic electroluminescent illuminating device which has the said organic electroluminescent element and the board | substrate by which this organic electroluminescent element is mounted and fixed, Comprising: The said organic substrate One of the electrodes of the EL element is disposed to face each other.

According to the present invention, the ratio of the propagation light of the organic EL element is maintained by defining the refractive index of the low refractive index layer disposed between the reflective layer or the reflective electrode layer and the light emitting layer to 1.4 or less. However, the film thickness of the low refractive index layer can be reduced, an increase in voltage between the reflective layer and the light emitting layer can be suppressed, and an increase in manufacturing cost can be suppressed.

Problems, configurations, and effects other than those described above will be apparent from the description of the embodiments below.

BRIEF DESCRIPTION OF THE DRAWINGS The longitudinal cross-sectional view which shows the whole structure of Embodiment 1 of the organic EL element which concerns on this invention, and an organic EL illuminating device using the same. The longitudinal cross-sectional view which shows the whole structure of Embodiment 2 of the organic EL element which concerns on this invention, and an organic EL illuminating device using the same. The longitudinal cross-sectional view which shows the whole structure of Embodiment 3 of the organic EL element which concerns on this invention, and an organic EL illuminating device using the same. The longitudinal cross-sectional view which shows the whole structure of Embodiment 4 of the organic EL element which concerns on this invention, and an organic EL illuminating device using the same. The longitudinal cross-sectional view which shows the whole structure of Embodiment 5 of the organic EL element which concerns on this invention, and an organic EL illuminating device using the same. FIG. 6 is a view showing a relationship between a wave number vector of an organic EL element and an emission mode according to an analysis model of Example 1. FIG. 6 is a graph showing the relationship between the refractive index of the low refractive index layer and the energy mode distribution according to the analysis model of Example 1. FIG. 6 is a graph showing the relationship between the film thickness of the low refractive index layer and the energy mode distribution according to the analysis model of Example 1. FIG. 18 is a graph showing the relationship between the refractive index of the hole injection layer and the energy mode distribution according to the analysis model of Example 4. The longitudinal cross-sectional view which shows the conventional organic EL element and the organic EL illuminating device using the same. The figure which shows the wave number vector of the conventional organic EL element, and the relationship of the light emission mode. The figure which shows the relationship between the light emission position of the conventional organic electroluminescent illuminating device, and energy mode distribution.

Hereinafter, embodiments of an organic EL element according to the present invention and an organic EL lighting device using the same will be described with reference to the drawings.

(Embodiment 1)
FIG. 1 shows the whole configuration of Embodiment 1 of the organic EL element according to the present invention and the organic EL illumination device using the same, and is a bottom emission type in which light emission of the organic EL element 10 is taken out from the substrate 100 side. An organic EL lighting device 1 is shown.

The organic EL lighting device 1 shown mainly includes an organic EL element 10 and a substrate 100 on which the organic EL element 10 is mounted and fixed. On the organic EL element 10 side, a light extraction layer 106 for extracting light confined in the organic EL element 10 is provided. In addition, flattening between the organic EL element 10 and the light extraction layer 106, on the side of the organic EL element 10 of the light extraction layer 106, is a planarization for connecting the organic EL element 10 and the light extraction layer 106 smoothly. Layer 120 is provided. The smoothing layer 120 is provided, for example, when the surface roughness Ra of the light extraction layer 106 is 5 nm or more.

The organic EL element 10 mainly includes an anode (the other electrode) including the transparent electrode 101, a cathode (the one electrode) 110 including the transparent electrode 103, and an organic layer 102 disposed between the anode and the cathode. The anode (transparent electrode 101) of the organic EL element 10 is disposed to face the substrate 100.

The cathode 110 is formed by laminating a transparent electrode (electrode layer) 103, a low refractive index layer 104, and a reflective layer 105 from the organic layer 120 side.

The organic EL lighting device 1 further includes a sealing substrate, an auxiliary wiring, an arrangement driving circuit, a housing, etc. (not shown), and the transparent electrode 103 constituting the cathode and the transparent electrode 101 constituting the anode are It is connected via an auxiliary wiring.

Hereinafter, each component which comprises the organic electroluminescent illuminating device 1 is explained in full detail.

[substrate]
As a formation material of substrate 100, materials, such as glass and a plastic, are applicable, for example. Further, when the organic EL lighting device 1 is a bottom emission type, the substrate 100 is transparent, but when the organic EL lighting device 1 is a top emission type described later (see FIG. 5), the substrate 100 is It may be transparent or opaque. Examples of the material for forming the transparent substrate 100 include glass, quartz, a transparent resin film, and the like.

Moreover, since the designability and the lightness effect are largely exhibited when the flexible substrate is more flexible than the rigid substrate, the material for forming the substrate 100 has flexibility that allows the organic EL element 10 to be flexible. Preferably, the provided resin film is applied. Examples of materials for forming such resin films include polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyethylene, polypropylene, cellophane, cellulose diacetate, cellulose triacetate, cellulose acetate butyrate, and cellulose acetate pro Cellulose esters such as propionate (CAP), cellulose acetate phthalate (TAC), cellulose nitrate or derivatives thereof, polyvinylidene chloride, polyvinyl alcohol, polyethylene vinyl alcohol, syndiotactic polystyrene, polycarbonate, norbornene resin, polymethylpentene , Polyether ketone, Polyimide, Polyether sulfone (PES), Polyphenylene sulf , Polysulfones, polyether imides, polyether ketone imides, polyamides, fluorocarbon resins, nylons, polymethyl methacrylates, acrylics or polyarylates, ARTON (trade name: manufactured by JSR Corporation) or APEL (trade name: manufactured by Mitsui Chemicals, Inc.) And cycloolefin resins and the like.

Moreover, the hybrid film which consists of a film of an inorganic substance and an organic substance, or both may be formed in the surface of the said resin film, and such a resin film is measured by the method based on JISK7129-1992, for example. It is preferable that the barrier film has a water vapor transmission rate (25 ± 0.5 ° C., relative humidity (90 ± 2)% RH) of 0.01 g / (m ² · 24 h) or less, JIS K 7126-1987. High barrier property film having an oxygen permeability of 0.001 cm ³ / (m ² · 24 h · atm) or less, and a water vapor transmission rate of 0.001 g / (m ² · 24 h) or less The water vapor transmission rate is more preferably 0.00001 g / (m ² · 24 h) or less.

The material for forming such a barrier film may be a material that suppresses the entry of factors (such as moisture and oxygen) that cause deterioration of the organic EL element 10, and examples thereof include silicon oxide, silicon dioxide, silicon nitride and the like. Be Furthermore, in order to improve the fragility of this film, the film preferably has a laminated structure of an inorganic substance and an organic substance. Although there is no restriction | limiting in particular about the order of lamination | stacking of the said inorganic substance and organic substance, It is preferable to laminate | stack both in multiple times alternately.

The method of forming the barrier film is not particularly limited, and examples thereof include vacuum evaporation, sputtering, reactive sputtering, molecular beam epitaxy, cluster-ion beam, ion plating, plasma polymerization, Atmospheric pressure plasma polymerization method, plasma CVD method, laser CVD method, thermal CVD method, coating method and the like can be applied.

In addition, as a formation material of the opaque board | substrate which can be employ | adopted when the organic electroluminescent illuminating device 1 is a top emission type (refer FIG. 5), metals, such as aluminum and stainless steel, opaque resin, a ceramic, etc. are mentioned, for example. .

[Light extraction layer]
As the light extraction layer 106, there are a light extraction layer of scattering particles and a light extraction layer of a structure such as a microlens array or a pyramid. In the present embodiment, since the light extraction layer 106 is used to extract the light confined in the organic EL element 10, there is no difference in the effect of the light extraction layer by the scattering fine particles and the light extraction layer by the structure. , Both can be applied.

The light extraction layer in which the former fine particles are dispersed is mainly composed of a matrix and fine particles, and the matrix is an organic compound and, if necessary, nanoparticles for increasing the average refractive index of the organic compound etc. (size not contributing to scattering Of nanoparticles, etc.). Thus, more light can be introduced into the light extraction layer 106 by disposing the light extraction layer in contact with the transparent electrode or the like by increasing the average refractive index of the matrix.

Examples of the material for forming the matrix constituting the light extraction layer 106 include ionizing radiation curable resins, thermosetting resins, thermoplastic resins, etc. Specifically, acrylate resins (epoxy acrylate, polyester acrylate, And radically polymerizable monomers or oligomers such as acrylic acrylate and ether acrylate), epoxy resins and the like. Here, examples of the ionizing radiation include ultraviolet light, visible light, infrared light, and electron beam.

In addition, an initiator may be added to the above-mentioned matrix, if necessary. As such an initiator, for example, a UV radical generator (Irgacure 907, 127, 192, etc. manufactured by Ciba Specialty Chemical Co., Ltd.), benzoyl peroxide and the like can be mentioned.

Further, as another resin component of the matrix, for example, aliphatic (for example, polyolefin) resin, urethane resin and the like can be mentioned, and the refractive index of this resin component is preferably 1.4 to 1.85, Preferably, it is 1.7 to 1.8. By having such a refractive index, more light can be taken into the matrix of the light extraction layer 106 to enhance the light extraction efficiency.

Here, it is preferable that the scattering particles in the light extraction layer 106 be particles having no or small light absorption (the absorptivity is usually 30% or less) in the visible light region. Examples of materials for forming such scattering particles include titanium oxide (refractive index: 2.5 or more and 2.7 or less), zirconium oxide (refractive index: 2.4), and barium titanate (refractive index: 2.4). And strontium titanate (refractive index: 2.37), bismuth oxide (refractive index: 2.45), etc. These materials may be used alone or in combination of two or more. It is also good. Among the materials for forming these scattering particles, particularly, materials made of inorganic materials are preferable, and the above-mentioned titanium oxide, zirconium oxide, barium titanate, strontium titanate, bismuth oxide and the like are preferable. Furthermore, the microparticles may be formed by voids in the matrix. The particle size of the fine particles is 100 nm or more, preferably 200 nm or more, and usually 10 μm or less, preferably 5 μm or less.

Such a light extraction layer 106 is generally formed by applying a coating liquid in which transparent fine particles are dispersed in a matrix precursor to the substrate 100. The content of the transparent fine particles in the coating solution is adjusted so that Mie scattering is multiple-scattered in the light extraction layer to be formed. As a coating method of this coating solution, for example, spin coating, dip coating, die coating, casting, spray coating, gravure coating, etc. are applied, and in particular, from the viewpoint of the uniformity of the coating, spin coating, dip coating, die coating, etc. Is applied.

The film thickness of the light extraction layer 106 is preferably 2 μm or more and 20 μm or less. When the film thickness is thinner than 2 μm, it is difficult to mix the scattering particles at a sufficient concentration, and when it is thicker than 20 μm, it becomes difficult to form a uniform coating film.

Further, in the light extraction layer based on the latter structure such as a microlens array or pyramid, it is necessary to arrange a structure of about 1 μm to 100 μm which is the light emission wavelength or more on one surface thereof. Assuming that the length of the base of the structure is d and the height from the base is h, the aspect ratio h / d should be in the range of 0.2 to 2 in order to increase the amount of light taken out to the outside. preferable.

In the case where the organic EL lighting device 1 adopts a device structure such as a display, for example, the light extraction layer 106 can be omitted.

[Transparent electrode (anode side)]
The transparent electrode 101 forming the anode is an electrode for injecting holes into the organic layer 102, and the material of the transparent electrode 101 is a metal, an alloy, an electrically conductive compound, or a material having a large work function. The electrode material etc. which consist of these mixtures are applied, and especially the electrode material whose work function is 4 eV or more is applied suitably. Examples of such an electrode material include metals such as Au (gold), and conductive transparent materials such as CuI, ITO (indium tin oxide), SnO ₂ , ZnO, and IZO (indium zinc oxide). Further, as a method of forming these electrode materials, for example, a vacuum evaporation method, a sputtering method, a CVD method, an ion plating method, a coating method or the like is applied, whereby the transparent electrode 101 can be formed as a thin film.

The light transmittance of the transparent electrode 101 is preferably 80% or more. The average sheet resistance value of the transparent electrode 101 is preferably several hundreds Ω / sq (square) or less, and more preferably 100 Ω / sq or less. Furthermore, the film thickness of the transparent electrode 101 is preferably 20 to 400 nm, preferably 20 to 200 nm although it varies depending on the material in order to define the transparency, conductivity and the like of the electrode (anode) as described above. Is desirable.

[Organic layer]
As shown in FIG. 1, the organic layer 102 is formed by laminating a hole injection layer 201, a hole transport layer 202, a light emitting layer 203, an electron transport layer 204, and an electron injection layer 205 from the transparent electrode 101 side. .

The organic layer 102 may be formed as a single layer structure of only the light emitting layer 203, or at least at least the light emitting layer 203, the hole injection layer 201, the hole transport layer 202, the electron transport layer 204 and the electron injection layer 205. It may be formed in a multilayer structure including a single layer. Also, even if the hole injection layer 201 and the hole transport layer 202, the hole transport layer 202 and the light emitting layer 203, the light emitting layer 203 and the electron transport layer 204, and the electron transport layer 204 and the electron injection layer 205 respectively abut. Alternatively, the above-described other layers may be interposed between the layers. That is, the stacking order of the hole injection layer 201, the hole transport layer 202, the light emitting layer 203, the electron transport layer 204, and the electron injection layer 205 can be changed as appropriate.

<Hole injection layer>
The hole injection layer 201 is a layer for reducing the injection barrier between the transparent electrode (anode) 101 and the hole transport layer 202, and is formed of a material having an appropriate ionization potential. In addition, it is desirable that the hole injection layer 201 also play a role of filling the unevenness of the surface of the transparent electrode 101 as the base. Examples of materials for forming such a hole injection layer 201 include copper phthalocyanine, starburst amine compound, polyaniline, polythiophene, vanadium oxide, molybdenum oxide, ruthenium oxide, aluminum oxide and the like. The hole injection layer 201 can be omitted as appropriate.

<Hole transport layer>
The hole transporting layer 202 is a layer for transporting holes from the transparent electrode 101 and injecting the holes into the light emitting layer 203, and is preferably formed of a hole transporting material having high hole mobility. In addition, it is preferable that the hole transport layer 202 be chemically stable, have a small ionization potential, a small electron affinity, and a high glass transition temperature. As a forming material of such a hole transport layer 202, for example, N, N′-bis (3-methylphenyl) -N, N′-diphenyl- [1,1′-biphenyl] -4,4 ′ diamine (TPD), 4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (α-NPD), 4,4 ′, 4 ′ ′-tri (N-carbazolyl) triphenylamine ( TCTA), 1,3,5-tris [N- (4-diphenylaminophenyl) phenylamino] benzene (p-DPA-TDAB), 4,4 ′, 4 ′ ′-tris (N-carbazole) triphenylamine (TCTA), 1,3,5-tris [N, N-bis (2-methylphenyl) -amino] -benzene (o-MTDAB), 1,3,5-tris [N, N-bis (3-) Methylphenyl) -amino] -benzene (m- MTDAB), 1,3,5-tris [N, N-bis (4-methylphenyl) -amino] -benzene (p-MTDAB), 4,4 ′, 4 ′ ′-tris [1-naphthyl (phenyl) Amino] triphenylamine (1-TNATA), 4,4 ′, 4 ′ ′-tris [2-naphthyl (phenyl) amino] triphenylamine (2-TNATA), 4,4 ′, 4 ′ ′-tris [ Biphenyl-4-yl- (3-methylphenyl) amino] triphenylamine (p-PMTDATA), 4,4 ′, 4 ′ ′-tris [9,9-dimethylfluoren-2-yl (phenyl) amino] tri Phenylamine (TFATA), 4,4 ′, 4 ′ ′-tris (N-carbazoyl) triphenylamine (TCTA), 1,3,5-tris- [N- (4-diphenylaminophenyl) phenylamino] Benzene (p-DPA-TDAB), 1,3,5-tris {4- [methylphenyl (phenyl) amino] phenyl} benzene (MTDAPB), N, N'-di (biphenyl-4-yl) -N, N'-diphenyl [1,1'-biphenyl] -4,4'-diamine (p-BPD), N, N'-bis (9,9-dimethylfluoren-2-yl) -N, N'-diphenyl Fluorene-2,7-diamine (PFFA), N, N, N ', N'-tetrakis (9,9-dimethylfluoren-2-yl)-[1,1-biphenyl] -4,4'-diamine ( FFD), (NDA) PP, 4-4′-bis [N, N ′-(3-tolyl) amino] -3-3′-dimethylbiphenyl (HMTPD), etc. You may use together and may use 2 or more types.

Further, an oxidant is contained in the hole transport material of the hole transport layer 202 in order to lower the injection barrier between the transparent electrode (anode) 101 and the hole transport layer 202 and to improve the electrical conductivity. It is also good. Examples of such an oxidizing agent include Lewis acid compounds such as ferric chloride, ammonium chloride, gallium chloride, indium chloride and antimony pentachloride, electron accepting compounds such as trinitrofluorene, and hole injecting materials. Vanadium oxide, molybdenum oxide, ruthenium oxide, aluminum oxide and the like can be applied, and these may be used singly or in combination of two or more.

<Light emitting layer>
The light emitting layer 203 contains host molecules and dopant molecules. The light-emitting organic compound used for the light-emitting layer 203 may be any one, for example, anthracene, naphthalene, pyrene, tetracene, coronene, perylene, phthaloperylene, naphthaloperylene, diphenylbutadiene, tetraphenylbutadiene, coumarin, oxa Diazole, bisbenzoxazoline, bisstyryl, cyclopentadiene, quinoline metal complex, tris (8-hydroxyquinolinate) aluminum complex, tris (4-methyl-8-quinolinate) aluminum complex, tris (5-phenyl-8-) Quinolinate) aluminum complex, aminoquinoline metal complex, benzoquinoline metal complex, tri- (p-terphenyl-4-yl) amine, 1-aryl-2,5-di (2-thienyl) pyrrole derivative, pyran, quina Pyrrolidone, rubrene, distyrylbenzene derivatives, di still arylene (DSA) derivatives, and, such as those containing these luminous organic compound in the molecule. Moreover, not only compounds derived from fluorescent dyes represented by these compounds but also materials capable of phosphorescent light emission from the triplet state, and compounds having a group consisting of these materials in a part of the molecule are suitably used. be able to.

<Electron transport layer>
The electron transport layer 204 is a layer for transporting electrons from the cathode 110 (particularly, the transparent electrode 103) and injecting the electrons into the light emitting layer 203, and is preferably formed of an electron transporting material having high electron mobility. Examples of materials for forming such an electron transport layer 204 include tris (8-quinolinol) aluminum, oxadiazole derivatives, silole derivatives, zinc benzothiazole complexes, vasocuproin (BCP), etc. These may be used alone or in combination. You may use and may use 2 or more types together.

In addition, a reducing agent may be contained in the electron transporting material of the electron transporting layer 104 in order to lower the injection barrier between the transparent electrode 103 and the electron transporting layer 204 or to improve the electrical conductivity. As such a reducing agent, for example, alkali metals, alkaline earth metals, alkali metal oxides, alkaline earth oxides, rare earth oxides, alkali metal halides, alkaline earth halides, rare earth halides, alkali metals And complexes formed with aromatic compounds, etc., and in particular, alkali metals such as cesium (Cs), lithium (Li), sodium (Na) and potassium (K) are preferably used, These materials may be used alone or in combination of two or more.

<Electron injection layer>
The electron injection layer 205 is a layer for enhancing the electron injection efficiency to the light emitting layer 203. For example, lithium fluoride, magnesium fluoride, calcium fluoride, strontium fluoride, barium fluoride, magnesium oxide, aluminum oxide, etc. These materials may be used alone or in combination of two or more. Note that this electron injection layer 205 can be omitted as appropriate.

[Transparent electrode (cathode side)]
The transparent electrode 103 forming the cathode 110 is an electrode for injecting electrons into the organic layer 102. As a material of the transparent electrode 103, an electrode material having a small work function is suitably applied. Examples of such an electrode material include conductive transparent materials such as ITO (indium tin oxide), SnO ₂ , ZnO, and IZO (indium zinc oxide), and graphene. As a method of forming these electrode materials, for example, a vacuum evaporation method, a sputtering method, a CVD method, an ion plating method, a coating method or the like is applied, whereby the transparent electrode 103 can be formed as a thin film.

Similar to the transparent electrode 101, the light transmittance of the transparent electrode 103 is preferably 80% or more. Further, the average sheet resistance value of the transparent electrode 103 is preferably several hundreds Ω / sq or less, and more preferably 100 Ω / sq or less. Furthermore, the film thickness of the transparent electrode 103 is preferably 20 to 400 nm, preferably 20 to 200 nm although it varies depending on the material in order to define the transparency, conductivity and the like of the electrode (cathode) as described above. Is desirable.

[Low refractive index layer]
The low refractive index layer 104 is a layer for suppressing surface plasmon coupling between the reflective layer 105 and the light emitting layer 203, and as a material for forming the low refractive index layer 104, for example, mesoporous silica or ionizing radiation curability Resin, thermosetting resin, thermoplastic resin etc. are mentioned. The refractive index of the low refractive index layer 104 is lower than the refractive index (for example, 1.8) of the organic layer 102 (in particular, the light emitting layer 203), and is preferably 1.4 or less, more preferably 1. It is 3 or less. For example, the refractive index of the low refractive index layer 104 can be reduced by providing a void of nanoparticle size in the low refractive index layer 104, and according to the current manufacturing method, about 1.2 to 1.4 It has been confirmed by the present inventors that a refractive index can be obtained.

Such a low refractive index layer 104 is usually formed by applying a coating solution containing the above-described material to the organic layer 102. As a method of applying this coating solution, for example, spin coating, dip coating, die coating, casting, spray coating, gravure coating, etc. are applied, and spin coating, dip coating, die coating are particularly preferred from the viewpoint of coating uniformity. It applies suitably.

The thickness of the low refractive index layer 104 is preferably 30 nm or more and 100 nm or less as described later, and desirably 40 nm or more and 100 nm or less. If the film thickness is smaller than 30 nm, surface plasmon coupling is increased, and the light extraction rate is rapidly reduced, or it becomes difficult to form a uniform coating film. Moreover, when the film thickness is thicker than 100 nm, it becomes difficult to form a uniform coating film.

[Reflective layer (or reflective electrode)]
The reflective layer 105 can increase the light extraction efficiency by applying a material with high reflectance, and is formed of, for example, a metal such as silver (Ag).

When the reflective layer 105 is also used as an electrode for injecting electrons into the organic layer 102 (referred to as a reflective electrode) (see FIG. 3), a metal having a small work function (for example, a metal having a work function of 5 eV or less) An electrode material consisting of an electrically conductive compound, and a mixture thereof is applied. Examples of such electrode materials include alkali metals, halides of alkali metals, oxides of alkali metals, alkaline earth metals, rare earths, and alloys of these with other metals. Examples thereof include sodium, sodium-potassium alloy, lithium, magnesium, aluminum, magnesium-silver mixture, magnesium-indium mixture, aluminum-lithium alloy, Al / Al ₂ O ₃ mixture, Al / LiF mixture and the like. Further, as a method of forming such a reflective electrode, for example, a vacuum evaporation method, a sputtering method, or the like can be applied, whereby the reflective electrode can be formed as a thin film.

The light transmittance of the reflective electrode is preferably 10% or less. Further, the film thickness of this reflective electrode differs depending on the material in order to define the light transmittance etc. of the reflective electrode as described above, but usually it is preferably 500 nm or less, preferably within the range of 100 to 200 nm. desirable.

[Sealing substrate]
As a sealing substrate (not shown in FIG. 1, refer to FIG. 5), for example, a transparent glass plate made of soda lime glass, non-alkali glass, etc., acrylic resin, polyethylene terephthalate (PET) resin, polyethylene naphthalate (PEN) resin Transparent plastic plate made of cycloolefin resin, olefin resin, carbonate resin, nylon resin, fluorine resin, silicone resin, polyimide resin, polysulfone resin, etc., in particular, a plastic substrate having an appropriate gas barrier film is applied Preferably. The sealing substrate may be light transmissive, may be colorless and transparent, or may be colored somewhat, but it is desirable to transmit light in the wavelength range of 380 nm to 780 nm.

[Auxiliary wiring]
The auxiliary wiring (not shown) is disposed on a line with a width of 1 μm to 20 μm on the

transparent electrodes

101 and 103 to reflect emitted light and reduce the resistance between the electrodes. The auxiliary wiring is preferably formed of a material comprising a metal or alloy having a high reflectance and a low resistance value, and as such a material, alkali metals, halides of alkali metals, these and other metals are used. Alloys such as silver, aluminum, sodium, sodium-potassium alloy, lithium, magnesium, aluminum, magnesium-silver mixture, magnesium-indium mixture, aluminum-lithium alloy, Al / Al ₂ O ₃ mixture, Al / LiF mixture etc. are mentioned. As a method of forming the auxiliary wiring, for example, a method such as a vacuum evaporation method or a sputtering method, a printing method, or the like can be applied, whereby the auxiliary wiring can be formed as a thin film. The light transmittance of the auxiliary wiring is preferably 10% or less.

According to the first embodiment, the low refractive index layer 104 having a refractive index lower than that of the light emitting layer 203 between the reflective layer 105 and the light emitting layer 203, particularly the low refractive index layer 104 having a refractive index of 1.4 or less. The thickness of the low refractive index layer 104 can be reduced while maintaining the ratio of the propagation light (light extraction efficiency) of the organic EL element 10 by providing the It is possible to suppress the increase in manufacturing cost.

Second Embodiment
FIG. 2 shows the whole structure of Embodiment 2 of the organic EL element concerning this invention, and an organic EL illuminating device using the same. The organic EL lighting device 1A of the second embodiment shown in FIG. 2 is different from the organic EL lighting device 1 of the first embodiment in the arrangement configuration of the light extraction layer, and the other configuration is substantially the same as that of the first embodiment. It is similar. Therefore, about the same composition as Embodiment 1, the same numerals are attached and the detailed explanation is omitted.

In the second embodiment, the light extraction layer 106A is provided between the substrate 100A and the air layer, that is, on the opposite side of the substrate 100A to the organic EL element 10A side, and the transparent electrode 101A of the organic EL element 10A and the substrate 100A. The organic EL element 10A is placed on and fixed to the substrate 100A so as to abut.

As described above, in the second embodiment, even when the light extraction layer 106A is provided on the opposite side of the substrate 100A to the organic EL element 10A side, the reflective layer 105A and the light extraction layer 106A are provided as in the first embodiment. By providing the low refractive index layer 104A having a refractive index lower than that of the light emitting layer 203A, particularly the low refractive index layer 104A having a refractive index of 1.4 or less, between the light emitting layer 203A, the light extraction of the organic EL element 10A The film thickness of the low refractive index layer 104A can be reduced while maintaining the efficiency.

In the second embodiment, the light extraction layer 106A is provided on the opposite side of the substrate 100A to the organic EL element 10A side, the organic EL element 10A and the substrate 100A are directly connected, and the planarization layer is omitted. ing.

(Embodiment 3)
FIG. 3 shows the whole structure of Embodiment 3 of the organic EL element concerning this invention, and an organic EL illuminating device using the same. The organic EL lighting device 1B of the third embodiment shown in FIG. 3 is different from the organic EL lighting device 1A of the above second embodiment in the arrangement configuration of the transparent electrode and the reflective layer on the cathode side, It is almost the same as in the second embodiment. Therefore, about the structure similar to Embodiment 2, the same code | symbol is attached | subjected and the detailed description is abbreviate | omitted.

In the third embodiment, the reflective layer is also used as an electrode for injecting electrons into the organic layer (such a reflective layer is referred to as a reflective electrode), and the organic EL element 10B mainly includes the anode (the other) composed of the transparent electrode 101B. And a cathode (one electrode) 110B including a reflective electrode 105B, and an organic layer 102B disposed between the anode and the cathode.

The cathode 110B is formed by laminating the low refractive index layer 104B and the reflective electrode (reflective electrode layer) 103B from the organic layer 120B side.

Here, since the low refractive index layer 104B generally has low conductivity, in Embodiment 3, carbon nanotubes, which are conductive materials in the low refractive index layer 104B disposed between the organic layer 120B and the reflective electrode 103B, are used. Conductivity is imparted by adding graphene and the like. The average sheet resistance value of such a low refractive index layer 104B is preferably 1000 Ω / □ or less.

As described above, in the third embodiment, the low refractive index layer 104B to which conductivity is imparted is disposed between the organic layer 120B and the reflective electrode 103B, thereby stably operating the organic EL lighting device 1B. The light extraction efficiency of the organic EL element 10B can be maintained, and the film thickness of the low refractive index layer 104B can be reduced.

(Embodiment 4)
FIG. 4 shows the whole structure of Embodiment 4 of the organic EL element concerning this invention, and an organic EL illuminating device using the same. The organic EL lighting device 1C of the fourth embodiment shown in FIG. 4 differs from the organic EL lighting device 1 of the first embodiment described above in the configuration of the hole injection layer of the organic layer, and the other configuration is the embodiment. Similar to 1. Therefore, about the same composition as Embodiment 1, the same numerals are attached and the detailed explanation is omitted.

The hole injection layer forming the organic layer generally has the same refractive index as that of the light emitting layer, but in the fourth embodiment, the hole injection layer (separate low refractive index layer) forming the organic layer 102C. The refractive index of 201 C is lower than the refractive index of the light emitting layer 203 C and the like.

As described above, in the fourth embodiment, the low refractive index layer 104B and the hole injection layer 201C having a refractive index lower than that of the light emitting layer 203C are disposed on both sides with respect to the light emitting layer 203C. By sandwiching the light emitting layer 203C with the hole injection layer (separate low refractive index layer) 201C, light emission from the light emitting layer 203C is converted from the substrate mode to the external mode by the cavity effect, so for example, the light extraction layer 106C Even when omitted, high light extraction efficiency can be ensured.

In the fourth embodiment described above, the refractive index of the hole injection layer 201C forming the organic layer 102C is lower than the refractive index of the light emitting layer 203C or the like. If a low refractive index layer having a refractive index lower than that of the light emitting layer 203C is disposed, the position where the low refractive index layer is disposed can be appropriately changed.

Embodiment 5
FIG. 5 shows the whole structure of Embodiment 5 of the organic EL element based on this invention, and the organic EL illuminating device using the same. The organic EL lighting device 1D of the fifth embodiment shown in FIG. 5 adopts a top emission type in which the light emission of the organic EL element is extracted from the side opposite to the substrate side to the organic EL lighting devices of the first to fourth embodiments described above. The other points are substantially the same as in the first to fourth embodiments. Therefore, the same components as those in the first to fourth embodiments are given the same reference numerals and the detailed description thereof will be omitted.

The illustrated organic EL lighting device 1D mainly includes the organic EL element 10D and the substrate 100D on which the organic EL element 10D is mounted and fixed, and the surface of the organic EL element 10D, particularly the transparent electrode of the organic EL element 10D A light extraction layer 106D is provided on the surface of 101D. A sealing substrate 107D is disposed on the surface of the light extraction layer 106D.

The organic EL element 10D mainly includes an anode (the other electrode) including the transparent electrode 101D, a cathode (the one electrode) 110D including the transparent electrode 103D, and an organic layer 102D disposed between the anode and the cathode. The cathode 110D of the organic EL element 10D is disposed to face the substrate 100D.

The cathode 110D is formed by laminating a transparent electrode (electrode layer) 103D, a low refractive index layer 104D, and a reflective layer 105D from the organic layer 120D side, and the reflective layer 105D is disposed in contact with the substrate 100D. .

First, a 50 mm square glass substrate 100D with a thickness of 1.1 mm is prepared. Then, aluminum (Al) is mask-deposited on the substrate 100D at a deposition rate of about 1 nm / s so as to have a width of 2 mm and a thickness of 150 nm to form a reflective layer 105D.

Next, a mesoporous silica layer is applied on the reflective layer 105D to a film thickness of 50 nm to form a low refractive index layer 104D, and an ITO film is formed on the low refractive index layer 104D by sputtering to form a transparent electrode. Form 103D. The refractive index of the low refractive index layer 104D is lower than the refractive index (for example, 1.8) of the organic layer 102D (in particular, the light emitting layer 203D), and as described later, preferably 1.4 or less, more preferably It is 1.3 or less.

Next, on the transparent electrode 103D, a layer obtained by doping a DSA derivative having a carbazolyl group at the end of a distyrylbiphenyl derivative ("DPVBi" manufactured by Idemitsu Kosan Co., Ltd. "BCzVBi" manufactured by Idemitsu Kosan Co., Ltd.) is 20 nm thick A blue light emitting layer formed as follows, a yellow light emitting layer formed to a thickness of 10 nm of a layer obtained by doping rubrene (manufactured by Acros) with α-NPD, and a layer obtained by doping a pyrromethene boron complex in rubrene A light emitting layer 203D is formed by laminating a red light emitting layer formed to have a thickness of 10 nm (electron transport layer 204D and electron injection layer 205D shown in FIG. 5 are omitted). Then, under a reduced pressure of 1.33 × 10 ⁻⁴ Pa, 4,4′-bis [N- (naphthyl) -N-phenyl-amino] biphenyl (manufactured by Dojin Chemical Research Laboratory, Inc.) on the light emitting layer 203D. The hole transport layer 202D is formed by depositing α-NPD at a deposition rate of 0.1 to 0.2 nm / s so as to have a thickness of 30 nm (the hole injection layer 201D shown in FIG. 5 is omitted). ).

Next, a transparent electrode 103D is formed on the hole transport layer 202D by sputtering using a mask so that IZO is formed in a strip shape having a width of 2 mm.

Next, on the transparent electrode 103, a light extraction layer 106D in which fine particles having a light scattering function are dispersed in a matrix (dispersion medium) such as a transparent resin layer is formed. The scattering particles in the light extraction layer 106D are mainly composed of, for example, TiO ₂ , ZrO ₂ , Al ₂ O ₃ , Ta ₂ O ₃ , ZnO ₂ , Sb ₂ O ₃ , ZrSiO ₄ , BaTiO ₃ , SrTiO ₃ . Inorganic particles, and organic particles of acrylic resin, styrene resin, polyethylene terephthalate resin, etc. can be applied. Among these scattering particles, inorganic particles are particularly preferable, and particles consisting of TiO ₂ , ZrO ₂ , Al ₂ O ₃ , BaTiO ₃ , SrTiO ₃ are particularly preferable.

Next, without exposing the substrate 100D on which the organic EL element 10D and the light extraction layer 106D are formed, high purity nitrogen gas is circulated to move to a sealing chamber holding a high dew point without exposing to the air. In addition, a sealing substrate 107D is introduced into the sealing chamber, and a sealing dispenser device is used to draw a photocurable resin for sealing on an edge portion of the sealing substrate 107D, and the sealing resin is attached to the light extraction layer 106D of the sealing substrate 107D. On the side to be joined, a sealing material made of epoxy resin (for example, a refractive index of about 1.5 at a wavelength of 587.6 nm) is applied.

Then, the substrate 100D and the sealing substrate 107D are introduced into the vacuum bonding apparatus in the sealing chamber, and the sealing substrate 107D is bonded and pressure-bonded to the light extraction layer 106D on the substrate 100D, and the entire organic EL element 10D is obtained. In a state where the light shielding plate is disposed so as not to be irradiated with UV light, the light curing resin is cured by irradiating the UV light from the sealing substrate 107D side.

Also in the top emission type organic EL lighting device 1D manufactured in this manner, as in the first to fourth embodiments, the low refractive index between the reflective layer 105D and the light emitting layer 203D is lower than that of the light emitting layer 203D. The film thickness of the low refractive index layer 104D can be reduced while maintaining the light extraction efficiency of the organic EL element 10D by providing the low refractive index layer 104D having the refractive index layer 104D, in particular, the refractive index of 1.4 or less. A rise in voltage between the 105D and the light emitting layer 203D can be suppressed, and a rise in manufacturing cost can be suppressed.

In the fifth embodiment, the mode in which the transparent electrode 103D and the reflective layer 105D are mainly used on the cathode side is described, but in the case where a reflective electrode is used on the cathode side (the reflective layer is used as an electrode for injecting electrons into the organic layer). (In Embodiment 3) (see Embodiment 3) can have the same form.

{Analysis that measured the light extraction efficiency of the organic EL lighting device and the result}
The inventors of the present invention create analysis models (Examples 1 to 5) corresponding to the above-described first to fifth embodiments, and compare the refractive index and the film thickness of the low refractive index layer with respect to each of the analysis models. The energy mode distribution analysis at the time of changing was performed.

In Examples 1 to 5, the electron injection layer and the electron transport layer are omitted from the above-described Embodiments 1 to 5, and the light emitting position (reflection layer or reflection electrode) is adjusted by adjusting the thickness of the low refractive index layer. Position of the light emitting layer with respect to

Example 1
The first embodiment is an analysis model corresponding to the first embodiment described above. Moreover, FIG. 6 is a figure which shows the wave number vector of the organic EL element by the model for analysis of Example 1, and the relationship of the light emission mode, and FIG. 7 shows the relationship between the refractive index of a low refractive index layer, and energy mode distribution. FIG. 8 is a view showing the relationship between the film thickness of the low refractive index layer and the energy mode distribution.

As described above, in the conventional organic EL lighting device (see FIG. 10), a large peak of the evanescent mode corresponding to the coupling intensity with the surface plasmon was observed (see FIG. 11). Further, the proportion of non-propagating light (light which can not be extracted from the organic EL element) increases as the light emitting position becomes smaller due to the evanescent mode, and propagating light (light which can be extracted to the outside from the organic EL element) It has been confirmed that when the emission position is about 200 nm, the proportion of the propagating light (light extraction efficiency) can be secured about 95%.

On the other hand, in the analysis model of Example 1, a low refractive index layer having a refractive index lower than that of the light emitting layer, particularly a low refractive index layer having a refractive index of 1.4 or less, is provided between the reflective layer and the light emitting layer. As shown in FIG. 6 (when the refractive index of the organic layer is 1.8, the refractive index of the low refractive index layer is 1.3, and the film thickness of the low refractive index layer is 65 nm), Almost no large peak was observed.

Specifically, as shown in FIG. 7 (when the refractive index of the organic layer is 1.8 and the film thickness of the low refractive index layer is 65 nm), the refractive index of the low refractive index layer is 1.4 or less In addition, it is confirmed that the proportion of non-propagating light in the evanescent mode is 5% or less, and the proportion of propagating light (light extraction efficiency) is 95% or more (light extraction efficiency that can be ensured by the conventional organic EL lighting device) It was done. That is, when the light extraction layer was used, it was demonstrated that the analysis model of Example 1 can achieve about 1.7 times the light extraction efficiency as compared with the conventional organic EL lighting device.

The light extraction efficiency is about 90% when the refractive index of the low refractive index layer is 1.5, and the light extraction efficiency when the refractive index of the low refractive index layer is 1.8, which is equivalent to that of the organic layer. Was confirmed to be about 70%.

Further, in the analysis model of Example 1, as shown in FIG. 8 (when the refractive index of the organic layer is 1.8 and the refractive index of the low refractive index layer is 1.3), the film thickness of the low refractive index layer is Even in the thin region, it was confirmed that the proportion of non-propagating light in the evanescent mode is small, and the proportion of propagating light (light extraction efficiency) is high. Specifically, when the film thickness of the low refractive index layer was 30 nm or more, it was confirmed that the proportion of the propagating light (light extraction efficiency) was 95% or more.

In addition, when the film thickness of the low refractive index layer was in the range of 40 nm to 100 nm, it was confirmed that the proportion of light that can be extracted in the external mode is about 40% or more. That is, in the conventional organic EL lighting device (when the emission position is 50 nm), the proportion of light that can be extracted in the external mode when the light extraction layer is not used is about 20%, while In the analysis model, it was confirmed that the ratio of light that can be extracted in the external mode is about 40% or more when the film thickness of the low refractive index layer is in the range of 40 nm to 100 nm. Therefore, when the light extraction layer is used, the analysis model of Example 1 can achieve about twice the light extraction efficiency and the power efficiency (lm / W) as compared with the conventional organic EL lighting device. Was demonstrated. Thus, for example, even in the case of adopting a device structure that does not use a light extraction layer such as a display, when the film thickness of the low refractive index layer is in the range of 40 nm to 100 nm, conventional organic EL illumination It has been demonstrated that the light extraction efficiency can be effectively enhanced over the device.

(Example 2)
The second embodiment is an analysis model corresponding to the second embodiment described above.

In the analysis model of the second embodiment, as in the analysis model of the first embodiment, when the refractive index of the low refractive index layer is 1.4 or less, the evanescent mode is used as compared with the conventional organic EL lighting device. It has been confirmed that the proportion of non-propagating light is reduced and the proportion of propagating light (light extraction efficiency) is enhanced. Moreover, even in the region where the film thickness of the low refractive index layer is thin, it has been confirmed that the proportion of non-propagating light in the evanescent mode is small, and the proportion of propagating light (light extraction efficiency) is high.

The present inventors confirmed by analysis and experiments that the same effect can be obtained even when the light extraction layer is provided on both the organic EL element side of the substrate and on the side opposite to the organic EL element side. ing.

(Example 3)
The third embodiment is an analysis model corresponding to the third embodiment described above.

In conducting energy mode distribution analysis, the inventors of the present invention performed an electric current test for 10000 hours and operated the organic EL lighting device when changing the sheet resistance value of the low refractive index layer to which the conductive substance was added. confirmed.

As a result, it was confirmed that the voltage increase was suppressed to about 10% in the conduction test for 10000 hours in the region where the average sheet resistance value is 1000 Ω / □ or less, and the organic EL lighting device stably operates. In addition, in the area | region where sheet resistance value exceeded 1000 ohms / square, the voltage increase by a conduction test becomes 20% or more, and it was confirmed that operation | movement of an organic electroluminescent illuminating device becomes unstable.

Then, the present inventors analyze the energy mode distribution when changing the refractive index and the film thickness of the low refractive index layer with respect to the analysis model of Example 3 when the average sheet resistance value is 1000 Ω / □. Carried out.

As a result, in the analysis model of the third embodiment, as in the analysis model of the first embodiment, when the refractive index of the low refractive index layer is 1.4 or less, as compared with the conventional organic EL lighting device, It has been confirmed that the proportion of non-propagating light due to the evanescent mode is reduced and the proportion of propagating light (light extraction efficiency) is enhanced. Moreover, even in the region where the film thickness of the low refractive index layer is thin, it has been confirmed that the proportion of non-propagating light in the evanescent mode is small, and the proportion of propagating light (light extraction efficiency) is high.

When the light extraction layer is used, the analysis model of Example 3 (the refractive index of the organic layer is 1.8, the refractive index of the low refractive index layer is 1.3, and the thickness of the low refractive index layer is In the case of 65 nm), it was confirmed that about 1.7 times the light extraction efficiency could be achieved as compared with the conventional organic EL lighting device as in the analysis model of Example 1.

When the light extraction layer is not used, the analysis model of Example 3 (the refractive index of the organic layer is 1.8, the refractive index of the low refractive index layer is 1.3, and the thickness of the low refractive index layer is 65 nm) In the case (1), similar to the analysis model of Example 1, it was demonstrated that about twice the light extraction efficiency and power efficiency (lm / W) can be achieved as compared with the conventional organic EL lighting device.

The present inventors have confirmed by analysis and experiments that the same effect can be obtained when the light extraction layer is disposed on the organic EL element side of the substrate, that is, between the substrate and the transparent electrode.

(Example 4)
The fourth embodiment is an analysis model corresponding to the fourth embodiment described above. FIG. 9 is a view showing the relationship between the refractive index of the hole injection layer (separate low refractive index layer) and the energy mode distribution according to the analysis model of the fourth embodiment.

As shown in FIG. 9 (where the refractive index of the organic layer is 1.8, the refractive index of the low refractive index layer is 1.3, and the thickness of the low refractive index layer is 65 nm) in the analysis model of Example 4 The ratio of light that can be extracted in the external mode when the light extraction layer is not used is about 40% when the refractive index of the hole injection layer is 1.6, and the refractive index of the hole injection layer is In the case of 1.3, it was confirmed to be about 50%. That is, it was demonstrated that the analysis model of Example 4 can achieve about 2.5 times the light extraction efficiency and the power efficiency (lm / W) as compared with the conventional organic EL lighting device.

When the light extraction layer is used, the analysis model of Example 4 achieves about 1.7 times the light extraction efficiency as compared with the conventional organic EL lighting device as shown in FIG. It has been demonstrated to gain.

(Example 5)
A fifth example is an analysis model corresponding to the fifth embodiment described above.

In the analysis model of the fifth embodiment, as in the analysis model of the first embodiment, when the refractive index of the low refractive index layer is 1.4 or less, the evanescent mode is used as compared with the conventional organic EL lighting device. It has been confirmed that the proportion of non-propagating light is reduced and the proportion of propagating light (light extraction efficiency) is enhanced. Moreover, even in the region where the film thickness of the low refractive index layer is thin, it has been confirmed that the proportion of non-propagating light in the evanescent mode is small, and the proportion of propagating light (light extraction efficiency) is high.

When the light extraction layer is used, the analysis model of Example 5 (the refractive index of the organic layer is 1.8, the refractive index of the low refractive index layer is 1.3, and the thickness of the low refractive index layer is In the case of 65 nm), it was confirmed that about 1.7 times the light extraction efficiency can be achieved as compared with the conventional organic EL lighting device.

When the light extraction layer is not used, the analysis model of Example 5 (the refractive index of the organic layer is 1.8, the refractive index of the low refractive index layer is 1.3, and the thickness of the low refractive index layer is 65 nm) In the case of (1), the proportion of light that can be extracted in the external mode is about 40% or more, and the light extraction efficiency and electric power are about twice that of the conventional organic EL lighting device as in the analysis model of Example 1. It has been demonstrated that an efficiency (lm / W) can be achieved.

In the first to fifth embodiments described above, when reference is made to the number and the like (including the number, numerical value, amount, range, etc.) relating to the constituent elements, they are clearly specified and clearly clearly limited to a specific number in principle. It is not limited to the specific number except for the case etc., and may be more or less than the specific number. In the first to fifth embodiments described above, when referring to the shapes, positional relationships, etc. of the components etc., the shapes thereof are substantially the same except when particularly clearly shown and when it is considered that the principle is not clearly apparent in principle. It is assumed that it includes things that are similar or similar to etc.

The present invention is not limited to the above-described first to fifth embodiments, but includes various modifications. For example, the above-described first to fifth embodiments are described in detail in order to explain the present invention in an easy-to-understand manner, and are not necessarily limited to those having all the configurations described. Further, part of the configuration of one embodiment can be replaced with the configuration of another embodiment, and the configuration of another embodiment can be added to the configuration of one embodiment. Moreover, it is possible to add, delete, and replace other configurations for part of the configurations of the respective embodiments.

1 Organic EL lighting device 10 Organic EL element 100 Substrate 101 Transparent electrode (anode) (other electrode)
102 Organic layer 103 Transparent electrode (electrode layer)
104 Low refractive index layer 105 reflective layer 105 B reflective electrode (reflective electrode layer)
106 Light Extraction Layer 107D Sealing Substrate 110 Cathode (One Electrode)
120 Smoothing layer 201 Hole injection layer 201C Hole injection layer (separate low refractive index layer)
202 Hole transport layer 203 Light emitting layer 204 Electron transport layer 205 Electron injection layer

Claims

An organic EL device comprising: a pair of electrodes; and an organic layer disposed between the electrodes and including a light emitting layer,
One of the electrodes is formed by laminating the electrode layer from the organic layer side, a low refractive index layer having a refractive index lower than that of the light emitting layer, and a reflective layer, and the low refractive index layer has a refractive index of 1.4. The organic electroluminescent element characterized by being the following.
The organic EL element has an additional low refractive index layer having a refractive index lower than that of the light emitting layer, and the light emitting layer is disposed between the low refractive index layer and the additional low refractive index layer. The organic EL device according to claim 1, characterized in that
The organic EL device according to claim 1, wherein the film thickness of the low refractive index layer is in the range of 30 nm to 100 nm.
An organic EL device comprising: a pair of electrodes; and an organic layer disposed between the electrodes and including a light emitting layer,
One of the electrodes is formed by laminating a low refractive index layer having a refractive index lower than that of the light emitting layer and to which conductivity is imparted from the organic layer side and a reflective electrode layer, and refraction of the low refractive index layer The rate is 1.4 or less, The organic EL element characterized by the above-mentioned.
The organic EL device according to claim 4, wherein an average sheet resistance value of the low refractive index layer is 1000 Ω / □ or less.
The organic EL element has an additional low refractive index layer having a refractive index lower than that of the light emitting layer, and the light emitting layer is disposed between the low refractive index layer and the additional low refractive index layer. The organic EL device according to claim 4, characterized in that
The organic EL device according to claim 4, wherein the film thickness of the low refractive index layer is in a range of 30 nm to 100 nm.
An organic EL lighting device comprising the organic EL element according to claim 1 and a substrate on which the organic EL element is mounted and fixed,
The other electrode of the said organic EL element is opposingly arranged by the said board | substrate, The organic electroluminescent illuminating device characterized by the above-mentioned.
The organic EL lighting device according to claim 8, wherein a light extraction layer is provided on the side opposite to the organic EL element side of the substrate and / or the organic EL element side of the substrate.
An organic EL lighting device comprising the organic EL element according to claim 1 and a substrate on which the organic EL element is mounted and fixed,
An organic EL lighting device, wherein one electrode of the organic EL element is disposed opposite to the substrate.
The organic EL lighting device according to claim 10, wherein a light extraction layer is provided on the surface of the other electrode of the organic EL element.
An organic EL lighting device comprising the organic EL element according to claim 4 and a substrate on which the organic EL element is mounted and fixed,
The other electrode of the said organic EL element is opposingly arranged by the said board | substrate, The organic electroluminescent illuminating device characterized by the above-mentioned.
The organic EL lighting device according to claim 12, wherein a light extraction layer is provided on the side of the substrate opposite to the organic EL element side and / or the organic EL element side.
An organic EL lighting device comprising the organic EL element according to claim 4 and a substrate on which the organic EL element is mounted and fixed,
An organic EL lighting device, wherein one electrode of the organic EL element is disposed opposite to the substrate.
The light extraction layer is provided in the surface of the other electrode of the said organic EL element, The organic electroluminescent illuminating device of Claim 14 characterized by the above-mentioned.