JP2007324062A - End face light emission type light emitting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an end face light emission type light emitting device with improved light extraction efficiency. <P>SOLUTION: The end face light emission type light emitting device extracts emitted light from at least one end face of a laminated structure having a pair of electrodes 4 and at least one light emitting layer sandwiched between the electrodes on one side of a plane of an optically transparent substrate. An electrode terminal part is formed on the plane, and at least one of an area which is not coated by the electrodes on the plane of the substrate, or the electrode terminal part is coated by light reflection layers 6, 7. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an edge-emitting light emitting device. In particular, the present invention relates to an edge-emitting light emitting device with improved light extraction efficiency.

In recent years, various functional elements have been developed and proposed. For example, an element that emits light when a voltage is applied, such as an organic electroluminescent element (hereinafter sometimes referred to as an organic EL element) and an inorganic electroluminescent element (hereinafter sometimes referred to as an inorganic EL element), or vice versa. There is known a photoelectric conversion element that generates electricity by irradiating light on the substrate.
In particular, an organic EL element using a thin film material that emits light when excited by passing an electric current can emit light with high luminance at a low voltage, so that it can be used for a mobile phone display, a personal digital assistant (PDA), a computer display, an automobile. It has a wide range of potential uses in a wide range of fields including information displays, TV monitors, or general lighting, and has advantages such as thinning, weight reduction, miniaturization, and power saving of devices in these fields. For this reason, the expectation as a leading role of the future electronic display market is great. However, in order to be practically used in place of conventional displays in these fields, many technical improvements such as light emission luminance and color tone, durability under wide usage environment conditions, low cost and mass productivity are problems. Yes.

  One of the problems of the light emitting element is that the light extraction efficiency is low. The light generated in the light emitting layer is extracted outside through the transparent substrate or the transparent electrode on the extraction surface. However, because the difference in refractive index between the substrate or electrode and the light-emitting layer or other functional layer and the difference in refractive index between the substrate or electrode and external air are large, the emitted light repeatedly undergoes total internal reflection within the device. The proportion of light that is effectively extracted to the outside due to internal absorption is generally 30% or less of the amount of emitted light.

  On the other hand, there is known an edge-emitting type light emitting element in which emitted light is extracted from an end face of a laminated body instead of passing through a substrate or an electrode. If the edge-emitting light-emitting element can effectively extract guided light that cannot be extracted from the plane of the substrate, the emission efficiency may be higher than that of the surface-emitting light-emitting element. However, in the case of the edge-emitting light emitting element, light leaks from other than the light extraction end face, and it is difficult to effectively extract light emission only from the light extraction end face.

2. Description of the Related Art Conventionally, attention has been paid to light leakage from end faces other than the light extraction end face, and its prevention means has been disclosed. For example, in a patent document in which an organic EL element is formed on a light guide member (see, for example, Patent Document 1), an end surface that does not extract light is on a surface that supports a laminated structure of a substrate, or on the opposite substrate surface. On the other hand, it is formed vertically, and Al is deposited on the vertical end face as a light reflecting agent. However, the vertical end face of the thin-layer substrate has a very small area, and it is not technically easy to deposit an aluminum reflective layer on the vertical end face, and even if it can be realized, the number of processes increases. In view of industrial productivity, such as an increase in the size of the device or the size of the device, it is inefficient and lacks feasibility.
It has been proposed to attach a plastic sheet in which a light reflecting material such as titanium oxide or zinc oxide is kneaded as a light reflecting member to a portion from which light is not extracted (for example, see Patent Document 2). However, the end surface of the thin-layer substrate has a very small area, and it is not easy to attach the plastic sheet with the necessary adhesive strength, and the feasibility is poor. In addition, such a plastic sheet is insulative, and there is a problem that the electrode portion such as the transparent electrode lead-out portion obstructs connection to the drive circuit.

On the other hand, means for reducing the amount of light that disappears due to repeated reflection in the transparent substrate is also disclosed. For example, the surface of the transparent substrate opposite to the surface carrying the light emitting element is provided with a saw-like uneven shape, and the uneven portion is covered with a light reflecting layer to suppress light attenuation due to repeated reflection. A technique for improving the light extraction efficiency has been proposed (see, for example, Patent Document 3).
However, even with these means, the light extraction efficiency from the end face is not sufficient, and further improvements are desired.
JP-A-10-208874 JP 2001-244067 A JP 2003-168553 A

  SUMMARY OF THE INVENTION An object of the present invention is to provide an edge-emitting light emitting device that can increase the light emission luminance from a desired end face.

The above-described problems of the present invention have been solved by the following means.
<1> An edge-emitting light-emitting element that takes out light emission from at least one end face of a stacked structure in which a pair of electrodes and at least one light-emitting layer are sandwiched between the electrodes on one plane of a light-transmitting substrate An electrode terminal portion is provided on the plane, and at least one of the region not covered with the electrode on the plane of the substrate or the electrode terminal portion is covered with a light reflecting layer. Edge-emitting light emitting device.
<2> The edge-emitting light-emitting element according to <1>, wherein the electrode terminal portion is covered with a light reflecting layer.
<3> The edge-emitting light emitting device according to <1>, wherein a region not covered with the electrode is covered with a light reflecting layer.
<4> The edge-emitting light emitting device according to <1>, wherein the region not covered with the electrode and the electrode terminal portion are covered with a light reflecting layer.
<5> The edge-emitting light emitting device according to any one of <1> to <4>, wherein the light reflecting layer is conductive.
<6> The edge-emitting light-emitting device according to any one of <1> to <5>, wherein the electrode terminal covered with the light reflecting layer is a terminal of a transparent electrode.
<7> The edge-emitting light-emitting element according to <6>, wherein the transparent electrode is indium tin oxide (hereinafter abbreviated as ITO).
<8> The edge-emitting light emitting device according to any one of <1> to <5>, wherein the electrode terminal is a metal thin film.
<9> The edge-emitting light-emitting device according to any one of <1> to <8>, wherein at least one of the end faces from which the laminated structure does not extract light is covered with a light reflecting layer. .
<10> In the end surface covered with the light reflecting layer, the end surface with respect to the surface of the substrate carrying the laminated structure or the surface opposite to the surface of the substrate carrying the laminated structure The edge-emitting light-emitting device according to <9>, wherein the angle formed by is an acute angle.
<11> The end face according to <9> or <10>, wherein light is extracted from one end face of the laminated structure, and the other three end faces from which light is not extracted are covered with a light reflecting layer. Light emitting type light emitting element.
<12> The edge-emitting light emitting device according to <10> or <11>, wherein an angle formed by the end face is 30 ° or more and 60 ° or less.
<13> The edge-emitting light emitting device according to any one of <1> to <12>, wherein the light reflecting layer contains aluminum, silver, gold, chromium, or an alloy thereof.
<14> The edge-emitting light emitting device according to <13>, wherein the light reflecting layer is a film formed by vapor deposition.
<15> The edge-emitting light-emitting device according to any one of <1> to <14>, wherein the light-emitting device is an organic electroluminescence device.
<16> The edge-emitting light-emitting device according to any one of <1> to <14>, wherein the light-emitting device is an inorganic electroluminescent device.

  According to the present invention, an edge-emitting light emitting device with improved light extraction efficiency is provided.

The edge-emitting light-emitting device of the present invention can effectively extract guided light that cannot be extracted from the plane of the substrate in the surface-emitting light-emitting device.
When extracting light that is trapped in the substrate from the end surface of the substrate, in order to achieve high extraction efficiency, light leakage from other than the light extraction end surface is effectively prevented, and light is emitted only from the light extraction end surface. It is important to have a structure that can emit light. As a result of earnest analysis of light leakage from other than the light extraction end face, the present inventors revealed light leakage from the following parts, and by providing a light leakage prevention structure for this, emission luminance from the light extraction end face Found a dramatic improvement.
-End face other than the light extraction end face-The portion of the surface of the substrate (light guide member) where the reflective member is not provided-Of the electrode of the light emitting element, the lead-out portion of the transparent electrode

The light-emitting element of the present invention is an edge-emitting device that emits light from at least one end surface of a stacked structure in which a pair of electrodes and at least one light-emitting layer are sandwiched between the electrodes on one plane of a light-transmitting substrate. The light emitting device has an electrode terminal portion on the plane, and at least one of the region not covered with the electrode on the plane of the substrate or the electrode terminal portion is covered with a light reflecting layer.
Preferably, the electrode terminal portion is covered with a light reflecting layer.
Preferably, a region not covered with the electrode is covered with a light reflecting layer.
More preferably, the region not covered with the electrode and the electrode terminal portion are covered with a light reflecting layer.
Preferably, the light reflecting layer is conductive.
Preferably, the electrode terminal covered with the light reflecting layer is a terminal of a transparent electrode. More preferably, the transparent electrode is ITO.
Preferably, the electrode terminal is a metal thin film.

Preferably, at least one of the end surfaces from which the light emission of the laminated structure is not extracted is covered with a light reflecting layer.
Preferably, in the end surface covered with the light reflecting layer, the end surface with respect to the surface of the substrate carrying the laminated structure or the surface opposite to the surface of the substrate carrying the laminated structure. The angle formed by is an acute angle.
Preferably, light emission is taken out from one end face of the laminated structure, and the other three end faces from which light emission is not taken out are covered with a light reflecting layer.

Preferably, the light reflecting layer is a film formed by vapor deposition. Preferably, the deposited film is a metal or a metal oxide.
Preferably, the light emitting device is an organic electroluminescent device or an inorganic electroluminescent device.

1. Organic electroluminescence device

Details will be described below. A conventionally well-known thing can be used as an organic electroluminescent element in this invention.
In addition to the light emitting layer, a conventionally known organic compound layer such as a hole transport layer, an electron transport layer, a block layer, an electron injection layer, and a hole injection layer may be included.
1) Layer structure <Electrode>
At least one of the pair of electrodes of the organic electroluminescent element of the present invention is a transparent electrode, and the other is a back electrode. The back electrode may be transparent or non-transparent.
<Configuration of organic compound layer>
There is no restriction | limiting in particular as a layer structure of the said organic compound layer, Although it can select suitably according to the use and objective of an organic electroluminescent element, It is formed on the said transparent electrode or the said back electrode. preferable. In this case, the organic compound layer is formed on the front surface or one surface on the transparent electrode or the back electrode.
There is no restriction | limiting in particular about the shape of a organic compound layer, a magnitude | size, thickness, etc., According to the objective, it can select suitably.

Specific examples of the layer configuration include the following, but the present invention is not limited to these configurations.
Anode / hole transport layer / light emitting layer / electron transport layer / cathode,
Anode / hole transport layer / light emitting layer / block layer / electron transport layer / cathode,
Anode / hole transport layer / light emitting layer / block layer / electron transport layer / electron injection layer / cathode,
Anode / hole injection layer / hole transport layer / light emitting layer / block layer / electron transport layer / cathode,
Anode / hole injection layer / hole transport layer / light emitting layer / block layer / electron transport layer / electron injection layer / cathode.

Each layer will be described in detail below.
2) Hole transport layer The hole transport layer used in the present invention contains a hole transport material. The hole transport material is not particularly limited as long as it has either a function of transporting holes or a function of blocking electrons injected from the cathode. As the hole transport material used in the present invention, any of a low molecular hole transport material and a polymer hole transport material can be used.
Specific examples of the hole transport material used in the present invention include the following materials.

Carbazole derivatives, triazole derivatives, oxazole derivatives, oxadiazol derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, Styryl anthracene derivative, fluorenone derivative, hydrazone derivative, stilbene derivative, silazane derivative, aromatic tertiary amine compound, styrylamine compound, aromatic dimethylidene compound, porphyrin compound, polysilane compound, poly (N-vinylcarbazole) derivative , Aniline copolymer, thiophene oligomer, conductive polymer oligomer such as polythiophene, polythiophene derivative, polyphenylene derivative, polyphenylene vinylene derivative, and polyphenylene Polymeric compounds such as orange derivatives.
These may be used alone or in combination of two or more.

  The thickness of the hole transport layer is preferably 10 nm to 200 nm, and more preferably 20 nm to 80 nm. If the thickness exceeds 200 nm, the driving voltage may increase. If the thickness is less than 10 nm, the light emitting element may be short-circuited, which is not preferable.

3) Hole injection layer In the present invention, a hole injection layer can be provided between the hole transport layer and the anode.
The hole injection layer is a layer that facilitates injection of holes from the anode into the hole transport layer, and specifically, a material having a small ionization potential is preferably used among the hole transport materials. For example, a phthalocyanine compound, a porphyrin compound, a starburst type triarylamine compound, etc. can be mentioned, It can use suitably.
The thickness of the hole injection layer is preferably 1 nm to 30 nm.

4) Light emitting layer The light emitting layer used in the present invention contains at least one kind of light emitting material, and may contain a hole transport material, an electron transport material, and a host material as necessary.
The light emitting material used in the present invention is not particularly limited, and either a fluorescent light emitting material or a phosphorescent light emitting material can be used. A phosphorescent material is preferred from the viewpoint of luminous efficiency.

  Examples of fluorescent light-emitting materials include benzoxazole derivatives, benzimidazole derivatives, benzothiazole derivatives, styrylbenzene derivatives, polyphenyl derivatives, diphenylbutadiene derivatives, tetraphenylbutadiene derivatives, naphthalimide derivatives, coumarin derivatives, perylene derivatives, perinone derivatives, oxalates. Diazole derivatives, aldazine derivatives, pyralidine derivatives, cyclopentadiene derivatives, bisstyrylanthracene derivatives, quinacridone derivatives, pyrrolopyridine derivatives, thiadiazolopyridine derivatives, styrylamine derivatives, aromatic dimethylidene compounds, 8-quinolinol derivative metal complexes and rare earths Various metal complexes represented by complexes, polythiophene derivatives, polyphenylene derivatives, polyphenylene vinylene derivatives, and polymers Polymeric compounds such as fluorene derivatives. These can be used alone or in combination of two or more.

  Although it does not specifically limit as a phosphorescent luminescent material, An ortho metalated metal complex or a porphyrin metal complex is preferable.

  The ortho-metalated metal complex includes, for example, Akio Yamamoto, “Organic Metal Chemistry: Fundamentals and Applications”, pages 150 to 232; Yersin's “Photochemistry and Photophysics of Coordination Compounds”, pages 71-77, pages 135-146, Springer-Verlag (published in 1987), etc. The use of the orthometalated metal complex as a light emitting material in the light emitting layer is advantageous in terms of high luminance and excellent light emission efficiency.

  There are various ligands that form the ortho-metalated metal complex, which are also described in the above documents. Among them, preferred ligands include 2-phenylpyridine derivatives, 7,8- Examples include benzoquinoline derivatives, 2- (2-thienyl) pyridine derivatives, 2- (1-naphthyl) pyridine derivatives, and 2-phenylquinoline derivatives. These derivatives may have a substituent if necessary. The orthometalated metal complex may have other ligands in addition to the above ligands.

The orthometalated metal complex used in the present invention can be obtained from Inorg Chem. 1991, 30, 1685, 1988, 27, 3464, 1994, 33, 545, Inorg. Chim. Acta, 1991, No. 181, page 245; Organomet. Chem. 1987, No. 335, 293, J. Am. Am. Chem. Soc. It can be synthesized by various known techniques such as 1985, No. 107, page 1431.
Among the ortho-metalated complexes, compounds that emit light from triplet excitons can be suitably used in the present invention from the viewpoint of improving luminous efficiency.

Of the porphyrin metal complexes, a porphyrin platinum complex is preferred.
A phosphorescent material may be used alone or in combination of two or more. Further, a fluorescent material and a phosphorescent material may be used at the same time.

  The host material is a material having a function of causing energy transfer from the excited state to the fluorescent light-emitting material or the phosphorescent light-emitting material, and as a result, causing the fluorescent light-emitting material or the phosphorescent light-emitting material to emit light.

The host material is not particularly limited as long as it is a compound capable of transferring exciton energy to the light emitting material, and can be appropriately selected according to the purpose. Specifically, a carbazole derivative, a triazole derivative, an oxazole derivative, Oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbene derivatives, silazane derivatives, aromatic Tertiary amine compounds, styrylamine compounds, aromatic dimethylidene compounds, porphyrin compounds, anthraquinodimethane derivatives, anthrone derivatives, diphenylquinone derivatives, thiopi Dioxide derivatives, carbodiimide derivatives, fluorenylidenemethane derivatives, distyrylpyrazine derivatives, heterocyclic tetracarboxylic anhydrides such as naphthaleneperylene, phthalocyanine derivatives, metal complexes of 8-quinolinol derivatives, metal phthalocyanines, benzoxazoles and benzothiazoles Various metal complexes represented by metal complexes as ligands, polysilane compounds, poly (N-vinylcarbazole) derivatives, aniline copolymers, thiophene oligomers, conductive polymer oligomers such as polythiophene, polythiophene derivatives, polyphenylene derivatives , Polymer compounds such as polyphenylene vinylene derivatives and polyfluorene derivatives. These compounds may be used individually by 1 type, and may use 2 or more types together.
As content in the light emitting layer of a host material, 0 mass%-99.9 mass% are preferable, More preferably, they are 0 mass%-99.0 mass%.

5) Block layer In this invention, a block layer can be provided between a light emitting layer and an electron carrying layer. The block layer is a layer that suppresses the diffusion of excitons generated in the light emitting layer, and also a layer that suppresses holes from penetrating to the cathode side.

  The material used for the block layer is not particularly limited as long as it is a material that can receive electrons from the electron transport layer and pass the electrons to the light emitting layer, and a general electron transport material can be used. For example, the following materials can be mentioned. Triazole derivatives, oxazole derivatives, oxadiazol derivatives, fluorenone derivatives, anthraquinodimethane derivatives, anthrone derivatives, diphenylquinone derivatives, thiopyrandioxide derivatives, carbodiimide derivatives, fluorenylidenemethane derivatives, distyrylpyrazine derivatives , Metal complexes of heterocyclic tetracarboxylic anhydrides such as naphthaleneperylene, phthalocyanine derivatives, 8-quinolinol derivatives and metal complexes having metal phthalocyanine, benzoxazole and benzothiazol as ligands Complex polymers, aniline copolymers, conductive polymer oligomers such as thiophene oligomers and polythiophenes, polythiophene derivatives, polyphenylene derivatives, polyphenylene vinylene derivatives, and polyfluorene derivatives. Mention may be made of the compound. These may be used individually by 1 type and may use 2 or more types together.

6) Electron transport layer In the present invention, an electron transport layer containing an electron transport material can be provided.
The electron transport material is not limited as long as it has either a function of transporting electrons or a function of blocking holes injected from the anode, and is mentioned when explaining the block layer. A suitable electron transport material can be used.
The thickness of the electron transport layer is preferably 10 nm to 200 nm, and more preferably 20 nm to 80 nm.

  If the thickness exceeds 200 nm, the driving voltage may increase, and if it is less than 10 nm, the light emitting device may be short-circuited.

7) Electron Injection Layer In the present invention, an electron injection layer can be provided between the electron transport layer and the cathode.
The electron injection layer is a layer that facilitates injection of electrons from the cathode into the electron transport layer. Specifically, lithium salts such as lithium fluoride, lithium chloride, and lithium bromide, sodium fluoride, sodium chloride, fluoride An alkali metal salt such as cesium, an insulating metal oxide such as lithium oxide, aluminum oxide, indium oxide, or magnesium oxide can be preferably used.
The thickness of the electron injection layer is preferably 0.1 nm to 5 nm.

8) Formation method of organic compound layer The organic compound layer is formed by a dry film forming method such as vapor deposition or sputtering, dipping, spin coating, dip coating, casting, die coating, or roll coating. The film can be suitably formed by any of wet film forming methods such as a coat method, a bar coat method, or a gravure coat method.
Of these, the dry method is preferred from the viewpoint of luminous efficiency and durability.

Next, the substrate and electrodes used in the organic electroluminescence device of the present invention will be described.
9) Substrate As the material of the substrate used in the present invention, both the first substrate and the second substrate are preferably materials that do not transmit moisture or materials with extremely low moisture permeability, and light emitted from the organic compound layer. A material that does not scatter or attenuate the light is preferable. Specific examples include, for example, YSZ (zirconia stabilized yttrium), inorganic materials such as glass, polyethylene terephthalate, polybutylene terephthalate, polyester such as polyethylene naphthalate, polystyrene, polycarbonate, Examples thereof include organic materials such as polyethersulfone, polyarylate, allyl diglycol carbonate, polyimide, polycycloolefin, norbornene resin, and synthetic resin such as poly (chlorotrifluoroethylene).
In the case of the organic material, it is preferable that the organic material is excellent in heat resistance, dimensional stability, solvent resistance, electrical insulation, workability, low air permeability, low moisture absorption, and the like. Among these, when the material of the transparent electrode is indium tin oxide (ITO) suitably used as the material of the transparent electrode, a material having a small difference in lattice constant from the indium tin oxide (ITO) is used. preferable. These materials may be used alone or in combination of two or more.

  There is no restriction | limiting in particular about the shape of a board | substrate, a structure, a magnitude | size, It can select suitably according to the use, purpose, etc. of a light emitting element. Generally, the shape is a plate shape. The structure may be a single layer structure, a laminated structure, may be formed of a single member, or may be formed of two or more members.

  The substrate may be colorless and transparent, or may be colored and transparent, but is preferably colorless and transparent in that it does not scatter or attenuate light emitted from the light emitting layer.

The substrate is preferably provided with a moisture permeation preventing layer (gas barrier layer) on the front surface or the back surface (on the transparent electrode side). As the material for the moisture permeation preventive layer (gas barrier layer), inorganic materials such as silicon nitride and silicon oxide are preferably used. The moisture permeation preventing layer (gas barrier layer) can be formed by, for example, a high frequency sputtering method.
The substrate may be further provided with a hard coat layer, an undercoat layer, and the like as required.

10) Anode As the anode used in the present invention, it is usually sufficient to have a function as an anode for supplying holes to the organic compound layer, and the shape, structure, size and the like are not particularly limited. Depending on the use and purpose of the light-emitting element, it can be appropriately selected from known electrodes.

  As a material for the anode, for example, a metal, an alloy, a metal oxide, an organic conductive compound, or a mixture thereof can be preferably cited. A material having a work function of 4.0 eV or more is preferable. Specific examples include semiconductive metals such as tin oxide doped with antimony and fluorine (ATO, FTO), tin oxide, zinc oxide, indium oxide, indium tin oxide (ITO), and zinc indium oxide (IZO). Metals such as oxides, gold, silver, chromium and nickel, and mixtures or laminates of these metals and conductive metal oxides, inorganic conductive materials such as copper iodide and copper sulfide, polyaniline, polythiophene, polypyrrole Organic conductive materials such as copper, and laminates of these with ITO.

  The anode is, for example, a printing method, a wet method such as a coating method, a physical method such as a vacuum deposition method, a sputtering method, or an ion plating method, or a chemical method such as a CVD or a plasma CVD method. Can be formed on the substrate in accordance with a method appropriately selected in consideration of suitability. For example, when ITO is selected as the anode material, the anode can be formed according to a direct current or high frequency sputtering method, a vacuum deposition method, an ion plating method, or the like. Moreover, when selecting an organic electroconductive compound as a material of an anode, it can carry out according to the wet film forming method.

  There is no restriction | limiting in particular as a formation position in the said light emitting element of an anode, Although it can select suitably according to the use and objective of this light emitting element, It is preferable to form on the said board | substrate. In this case, the anode may be formed on the entire one surface of the substrate or a part thereof.

  The patterning of the anode may be performed by chemical etching such as photolithography, or may be performed by physical etching using a laser or the like, or may be performed by vacuum deposition or sputtering by overlapping a mask. Etc., or may be performed by a lift-off method or a printing method.

The thickness of the anode can be appropriately selected depending on the material and cannot be generally defined, but is usually 10 nm to 50 μm, and preferably 50 nm to 20 μm.
The resistance value of the anode is preferably 10 ³ Ω / □ or less, and more preferably 10 ² Ω / □ or less.

The anode may be colorless and transparent or colored and transparent. In order to extract light emitted from the anode side, the transmittance is preferably 60% or more, and more preferably 70% or more. This transmittance can be measured according to a known method using a spectrophotometer.
In the present invention, it is preferable that the electrode provided in advance on the transparent substrate is a light transmissive electrode in order to efficiently guide the generated light emission to the transparent substrate serving as the light guide member. A particularly preferred anode electrode is ITO.

  The anode is described in detail in the book “New Development of Transparent Electrode Film”, published by CMC (1999), supervised by Yutaka Sawada, and these can be applied to the present invention. When using a plastic substrate having low heat resistance, an anode formed using ITO or IZO at a low temperature of 150 ° C. or lower is preferable.

11) Cathode As a cathode that can be used in the present invention, it suffices as long as it normally has a function as a cathode for injecting electrons into the organic compound layer, and the shape, structure, size and the like are not particularly limited. However, it can be appropriately selected from known electrodes according to the use and purpose of the light-emitting element.

  Examples of the material for the cathode include metals, alloys, metal oxides, electrically conductive compounds, and mixtures thereof, and those having a work function of 4.5 eV or less are preferable. Specific examples include alkali metals (for example, Li, Na, K, or Cs), alkaline earth metals (for example, Mg, Ca, etc.), gold, silver, lead, aluminum, sodium-potassium alloys, lithium-aluminum alloys, Examples thereof include magnesium-silver alloys, rare earth metals such as indium and ytterbium. These may be used alone, but from the viewpoint of achieving both stability and electron injection properties, two or more of them can be suitably used in combination.

  Among these, alkali metals and alkalinity metals are preferable from the viewpoint of electron injection properties, and materials mainly composed of aluminum are preferable from the viewpoint of excellent storage stability. The material mainly composed of aluminum is aluminum alone, or an alloy or mixture of aluminum and 0.01% by mass to 10% by mass of alkali metal or alkaline earth metal (for example, lithium-aluminum alloy, magnesium-aluminum alloy, etc. ).

  The cathode materials are described in detail in JP-A-2-15595 and JP-A-5-121172, and these can be applied to the present invention.

  There is no restriction | limiting in particular in the formation method of a cathode, It can carry out according to a well-known method. For example, a printing method, a wet method such as a coating method, a physical method such as a vacuum deposition method, a sputtering method, or an ion plating method, a chemical method such as a CVD method or a plasma CVD method, etc. It can be formed on the substrate according to a method appropriately selected in consideration of suitability. For example, when a metal or the like is selected as the material of the cathode, one or more of them can be simultaneously or sequentially performed according to a sputtering method or the like.

  The patterning of the cathode may be performed by chemical etching such as photolithography, or may be performed by physical etching using a laser or the like, or vacuum deposition or sputtering is performed with a mask overlapped. It may be performed by a lift-off method or a printing method.

There is no restriction | limiting in particular as a formation position in the organic electroluminescent element of a cathode, Although it can select suitably according to the use and objective of this light emitting element, forming in an organic compound layer is preferable. In this case, the cathode may be formed on the entire organic compound layer or a part thereof.
Further, a dielectric layer made of the alkali metal or the alkaline earth metal fluoride may be inserted between the cathode and the organic compound layer with a thickness of 0.1 nm to 5 nm.
The dielectric layer can be formed by, for example, a vacuum deposition method, a sputtering method, or an ion plating method.

The thickness of the cathode can be appropriately selected depending on the material and cannot be generally defined, but is usually 10 nm to 5 μm, and preferably 50 nm to 1 μm.
The cathode may be transparent or opaque. The transparent cathode can be formed by forming the cathode material into a thin film with a thickness of 1 nm to 10 nm and further laminating the transparent conductive material such as ITO or IZO.

2. Inorganic electroluminescent element As an inorganic electroluminescent element in this invention, a conventionally well-known thing can be used.
For example, the inorganic electroluminescent element used in the present invention includes a first and second insulating films made of oxide having a high dielectric constant disposed between electrodes, and a light emitting made of sulfide sandwiched between the insulating films. Includes functional layers such as layers. As the insulating layer, materials such as tantalum pentoxide (Ta ₂ O ₅ ), titanium oxide (TiO ₂ ), yttrium oxide (Y ₂ O ₃ ), barium titanate (BaTiO ₃ ), strontium titanate (SrTiO ₃ ), etc. Can be used. As the light emitting layer, materials such as zinc sulfide (ZnS), calcium sulfide (CaS), strontium sulfide (SrS), barium thioaluminate (BaAl ₂ S ₄ ) are used as the base material of the light emitting layer, and manganese is used as the light emitting center. A transition metal element such as (Mn) or a rare earth element such as europium (Eu), cerium (Ce), or terbium (Tb) can be used.

3. Photoelectric Conversion Element Conventionally known elements can be used as the photoelectric conversion element in the present invention.
For example, a photoelectric conversion element used in the present invention includes a semiconductor layer having a pn junction or a pin junction between electrodes, a functional layer such as an X-ray photoconductor layer that generates charges by X-ray irradiation, a photodetector, a solar cell It can be used for X-ray detectors. The material is appropriately selected according to each application. Amorofas silicon (a-Si), polycrystalline silicon, amorofas selenium (a-Se), cadmium sulfide (CdS), cadmium telluride (CdTe), zinc oxide (ZnO) ), Lead oxide (PbO), lead iodide (PbI ₂ ), Bi ₁₂ (Ge, Si) O ₂₀ , or the like can be used. These can be doped with impurities as needed to control the conductivity type.

4). Other element components (resin sealing layer)
The functional element of the present invention preferably suppresses deterioration of element performance due to oxygen or moisture by contact with the atmosphere by the resin sealing layer.
<Material>
The resin material for the resin sealing layer is not particularly limited, and an acrylic resin, an epoxy resin, a fluorine resin, a silicon resin, a rubber resin, an ester resin, or the like can be used. An epoxy resin is preferable from the viewpoint of the prevention function. Among the epoxy resins, a thermosetting epoxy resin or a photocurable epoxy resin is preferable.
<Production method>
The method for producing the resin sealing layer is not particularly limited, and examples thereof include a method of applying a resin solution, a method of pressure bonding or thermocompression bonding of a resin sheet, and a method of dry polymerization by vapor deposition or sputtering.
<Film thickness>
The thickness of the resin sealing layer is preferably 1 μm or more and 1 mm or less. More preferably, they are 5 micrometers or more and 100 micrometers or less, Most preferably, they are 10 micrometers or more and 50 micrometers or less. If it is thinner than this, the inorganic film may be damaged when the second substrate is mounted. On the other hand, if the thickness is larger than this, the thickness of the electroluminescent element itself is increased, and the thin film property that is characteristic of the organic electroluminescent element is impaired.

(Sealing adhesive)
The sealing adhesive used in the present invention has a function of preventing intrusion of moisture and oxygen from the end portion.
<Material>
As the material of the sealing adhesive, the same material as that used for the resin sealing layer can be used. Among these, epoxy adhesives are preferable from the viewpoint of moisture prevention, and among them, a photocurable adhesive or a thermosetting adhesive is preferable.

It is also preferable to add a filler to the above material.
The filler added to the sealant is preferably an inorganic material such as SiO ₂ , SiO (silicon oxide), SiON (silicon oxynitride) or SiN (silicon nitride). Addition of the filler increases the viscosity of the sealant, improves processing suitability, and improves moisture resistance.

<Drying agent>
The sealing adhesive may contain a desiccant. As the desiccant, barium oxide, calcium oxide, or strontium oxide is preferable.
The amount of the desiccant added to the sealing adhesive is preferably 0.01% by mass or more and 20% by mass or less, and more preferably 0.05% by mass or more and 15% by mass or less. If the amount is less than this, the effect of adding the desiccant is diminished. On the other hand, when it is more than this, it becomes difficult to uniformly disperse the desiccant in the sealing adhesive, which is not preferable.
<Prescription of sealing adhesive>
・ Polymer composition, concentration,
It does not specifically limit as a sealing adhesive agent, The said thing can be used. For example, XNR5516 manufactured by Nagase Chemtech Co., Ltd. can be cited as a photo-curable epoxy adhesive. What is necessary is just to add and disperse | distribute the said desiccant directly there.
-Thickness The coating thickness of the sealing adhesive is preferably 1 μm or more and 1 mm or less. If it is thinner than this, the sealing adhesive cannot be applied uniformly, which is not preferable. On the other hand, if it is thicker than this, the route through which moisture invades becomes wide, which is not preferable.
<Sealing method>
In the present invention, a functional element can be obtained by applying an arbitrary amount of the sealing adhesive containing the desiccant with a dispenser or the like, and stacking and curing the second substrate after application.

5). Element Structure The element structure of the present invention will be described with reference to the drawings. In the following description, sealing structures and lead wires that are not directly related to the purpose of the present invention are omitted from the drawings for the sake of simplicity.
FIG. 1 is a schematic view of a conventional end surface light emitting device. 1A is a plan view, FIG. 1B is a cross-sectional view taken along line AA ′, and FIG. 1C is a cross-sectional view taken along line BB ′. A light transmissive electrode 2 (anode), an organic functional layer 3, and a light impermeable electrode 4 (cathode) are stacked on one surface of the light transmissive substrate 1. A light reflecting layer 7 is provided on the other surface of the substrate. A terminal portion 2 a is configured and arranged at one end of the light transmissive electrode 2. Of the four end surfaces, the end surface S is a light extraction end surface, and the other three end surfaces R1, R2, and R3 are end surfaces that are not intended for light extraction.

  FIG. 2 is a schematic view of an example of the end surface light emitting device of the present invention. 2A is a plan view, FIG. 2B is a cross-sectional view taken along line A-A ′, and FIG. 2C is a cross-sectional view taken along line B-B ′. 1 has a laminated structure similar to that of the conventional device of FIG. 1, and an insulating layer 5 is disposed on the terminal portion, and light reflection is performed so as to cover a portion where the electrode of the terminal portion does not exist and a portion where the light impermeable electrode 4 does not exist. It has a layer 6.

  FIG. 3 is a schematic view of another example of the end surface light emitting device of the present invention. 3A is a plan view, FIG. 3B is a cross-sectional view taken along line A-A ′, and FIG. 3C is a cross-sectional view taken along line B-B ′. 1 has a laminated structure similar to that of the conventional element of FIG. 1, and has an insulating layer 5 and a light reflecting layer 6 in the terminal portion as in the element of FIG. Further, the three end surfaces R1, R2, and R3 other than the light extraction end surface S are tapered, and the end surfaces are cut off at an acute angle with respect to the surface having the laminated structure of the substrate. An insulating layer 8 is provided on the surface having no laminated structure of the substrate and end faces R1, R2, and R3, and a light reflecting layer 7 is further laminated thereon.

  In the end face light emitting device, when a voltage is applied between the light transmissive electrode and the cathode, the portion of the organic thin film inserted by the electrode emits light. The generated light is repeatedly reflected between the light reflection layer 7 and the light-impermeable electrode 4 which is light-reflective, guided in the transparent substrate 1, and emitted from the light-transmissive portion of the element. In the case of a conventional end surface light emitting device, light leaks in an unintended direction from the other three end surfaces R1, R2, and R3 in addition to the light extraction end surface S. In addition, light leakage occurs from a portion not covered with the light non-transparent electrode of the element and a lead-out portion of the transparent electrode. These light leaks cause a significant reduction in the extraction efficiency of the end face light emitting device.

  In the example of the edge light emitting device of the present invention shown in FIG. 2, the light reflecting electrode 6 has a lead portion of the light transmissive electrode that is light transmissive in the conventional device and a terminal portion of the light transmissive substrate that is not covered with the electrode. It is covered and light leakage from this part is prevented. The insulating layer 5 is an insulating layer provided to prevent the anode 2 and the cathode 4 of the light emitting element from being short-circuited. In this aspect, light leakage from the lead-out portion of the transparent electrode and a part of the substrate not covered with the electrode is prevented, so that light emission from the light extraction end surface S is enhanced.

  In another example of the end surface light emitting device of the present invention shown in FIG. 3, the light reflecting layer 7 includes end surfaces R1, R2, other than the light extraction end surface, in addition to the surface opposite to the substrate surface on which the light emitting device is provided. And R3. Thereby, light leakage from end surfaces other than the light extraction end surface S is prevented. By forming the end face not intended for light extraction into a tapered shape, the step of providing the light reflecting layer on the end face by vacuum deposition can be easily performed. Before providing the light reflecting layer, the end face can be processed into a tapered shape, and the light reflecting layer 7 on the back surface of the substrate and the light reflecting layer on the tapered portion can be installed simultaneously. When the reflective layer 7 is conductive, a structure in which the electrodes are completely insulated by the insulating layer 8 can be used so that the anode and the cathode are not short-circuited via the reflective layer 7. Further, the transparent substrate-coated reflective layer 6 is electrically connected to the anode 2 and can serve as an extraction electrode for the anode as well as preventing light leakage.

  The taper processing of the substrate end surface means that the angle formed by the end surface with respect to the surface supporting the functional layer of the transparent substrate or the surface opposite to the surface supporting the functional layer of the substrate is processed into an acute angle, This shape may be called a taper shape. Preferably, an angle formed by the end surface with respect to the substrate surface is processed into an acute angle in three surfaces other than the end surface from which the light emission is extracted. Preferably, the angle formed by the end faces is 30 ° to 60 °, more preferably 40 ° to 50 °. Preferably, the area of the end face is 15% or more, more preferably 30% or more larger than the cross-sectional area of the end face. By increasing the area of the end face, the light reflecting layer is stably provided with a sufficient thickness. If the angle formed by the end face exceeds 60 °, it is not preferable because the end face area decreases and it becomes difficult to provide the light reflecting layer. On the other hand, if the angle is less than 30 °, the strength of the edge of the substrate is lowered, and it is not preferable because it is chipped or broken. The angle of the end face is an average angle. The shape of the inclined surface of the end surface is not necessarily a flat surface. The shape may be a streak shape, a staircase shape, or a curved shape such as a wave shape or a ripple shape. The smaller the area of the inclined surface and the smaller the area that is hidden from the vapor deposition source during vapor deposition, the easier it is to provide a light reflecting layer. It is preferable to select so that it does. All end faces may have the same tapered shape or may be different. Alternatively, one end surface may be tapered at an acute angle with respect to the surface having the light emitting layer of the substrate, and the other end surface may be tapered at an acute angle with respect to the surface opposite to the surface having the light emitting layer of the substrate. Good (reverse taper processing), and their shapes may be different.

The taper processing is performed by cutting a cross section of the end portion.
The taper process can be performed after or before the light-emitting element is manufactured. Any method may be used for the end surface taper processing as long as a desired end surface shape can be realized. For example, a method by polishing using a grindstone can be suitably applied to the present invention. As a method, the substrate end is brought into contact with the rotating grindstone while being inclined at a desired angle. The end surface of the substrate is cut by a grindstone, and a substrate end surface that is tapered with respect to the substrate plane can be realized. At this time, since the end face is normally in a ground glass state, it can be further polished as necessary to form a smooth plane. Examples of other taper processing methods include a sand blast method and a press processing method. In the sandblast method, taper processing is performed by spraying fine particles of a grindstone on the end face of the substrate.
In the press working, the end surface is processed into a tapered shape using a mold at the stage of producing a glass substrate.

The light reflecting layer used in the present invention reflects generated light and enables efficient light extraction from the end face. The light reflecting layer preferably has a light reflectance of 50% or more. More preferably, it is 70% or more. A metal or a metal oxide is preferable, and a metal such as aluminum, silver, gold, and chromium is more preferable.
As the light reflecting layer, there are a back surface reflecting layer, an electrode terminal portion or a light reflecting layer not covered with an electrode on the other plane of the substrate, and a light reflecting layer on an end face other than the light extraction end face. The material of the reflective layer may be the same or different.
The light reflecting layer may be formed by any means. In the present invention, the light reflecting layer is preferably formed by vapor deposition. The light reflecting layer is preferably deposited to a thickness of 0.01 μm to 1 μm, more preferably 0.05 μm to 0.2 μm.

  The procedure for forming the electrode and the functional layer on the substrate and for forming the light reflecting layer may be any procedure. For example, after the back surface reflection layer is installed on one plane of the substrate, the electrode and the functional layer are provided on the other plane of the substrate, and then the light reflection layer is deposited on the electrode terminal portion or the portion not covered with the electrode, Alternatively, the light reflecting layer may be deposited on an end face other than the light extraction end face. Alternatively, after providing an electrode and a functional layer on one plane of the substrate, vapor deposition of the back surface reflection layer on the other plane of the substrate, vapor deposition of the light reflection layer on the electrode terminal portion or a portion not covered with the electrode, and light You may vapor-deposit the light reflection layer on end surfaces other than an extraction end surface.

  As the light reflecting layer, there are a back surface reflecting layer, an electrode terminal portion or a light reflecting layer not covered with an electrode on the other plane of the substrate, and a light reflecting layer on an end face other than the light extraction end face. The material of the reflective layer may be provided in sequential steps, or may be performed simultaneously by rotating the light emitting element or the vapor deposition source, or using a multi-station vapor deposition source.

  Any insulating layer 5 and insulating layer 8 may be used as long as the purpose of preventing a short circuit between the electrodes can be achieved, and a dry film forming method or a wet film forming method may be used. Further, when the reflective layer does not have conductivity, the insulating layer may be omitted.

  The present invention improves the light extraction efficiency by the transparent substrate-covered reflective layer 6 illustrated in FIGS. 2 and 3, and further improves the light extraction efficiency of the edge light emitting element by the light reflection layer 7 covering the end surface R other than the light extraction end surface. An element structure based on this idea is intended to be improved, and is within the scope of the present invention regardless of the above description.

  The present invention will be described more specifically with reference to the following examples. However, the present invention is not limited to the examples described below.

Example 1
1. Device fabrication (Comparative device: Comparative Example 1)
This is an example of manufacturing a conventional edge light emitting device 1A. Related figures are FIGS. 4-7.
On the alkali-free glass substrate 11 of 30 mm (length) × 40 mm (width) × 1 mm (thickness), a transparent anode electrode 12 made of ITO was formed into a film thickness of 200 nm by a sputtering method, and shaped by wet etching. The resulting structure is shown in FIG. 4A is a schematic plan view, and FIG. 4B is a cross-sectional view taken along line AA ′. A portion indicated by 12a is a lead-out portion of the ITO electrode.

Next, the organic EL layer 13 was deposited using an evaporation mask having an opening at a predetermined position. The resulting structure is shown in FIG. FIG. 5A is a schematic plan view, and FIG. 5B is a cross-sectional view taken along line AA ′.
As an organic EL layer, a hole injection layer composed of 30 nm MTDATA [4,4 ′, 4 ″ -tris (3-methylphenylphenylamino) triferamine], 20 nm α-NPD (N, N′-dinaphthyl) -N, N'-diphenyl- [1,1'-biphenyl] 4,4'-diamine) hole transport layer, 30 nm host Alq3 (tris (8-hydroxyquinonato) aluminum) and luminescent material t A light emitting layer doped with (npa) py (1,3,6,8-tetra [N- (naphthyl) -N-phenylamino] pyrene) and an electron transport layer composed of 20 nm of Alq3 were sequentially formed by vacuum deposition.

Next, an organic EL element was manufactured by forming a cathode electrode 14 made of aluminum (Al) so as to cover the organic EL layer using an upper electrode deposition mask having an opening at a predetermined position. The resulting structure is shown in FIG. 6A is a schematic plan view, and FIG. 6B is a cross-sectional view taken along line AA ′.
Next, a glass cap was bonded with a thermosetting adhesive so as to cover the organic EL element portion and sealed (not shown).

Next, as shown in FIG. 7, a light reflecting layer 15 made of an aluminum vapor deposition film was formed on the surface of the substrate opposite to the side where the light emitting element was provided.
Then, the element 1A was obtained by optically polishing the light extraction end face to form a clean light extraction end face.

(Element of the present invention: edge-emitting organic EL element 1B)
An edge-emitting organic EL device 1B according to the present invention was produced as follows. Related figures are FIGS. 8-10.
The process until Comparative Example 1 was performed until the cathode electrode 14 was formed.
Next, an insulating layer 16 made of 1,3-bis (9-carbazolyl) benzene (mCP) for preventing short-circuiting between electrodes was formed by vacuum evaporation using an insulating layer evaporation mask having openings at predetermined positions. The resulting structure is shown in FIG. FIG. 8A is a schematic plan view, and FIG. 8B is a cross-sectional view taken along line AA ′.
Next, the lead-out portion of the transparent electrode and the portion not covered with the electrode of the transparent substrate were covered with a 50 nm aluminum vapor-deposited film 17 to form a light reflecting layer. The light reflecting layer 17 is electrically connected to the anode lead portion of the element and functions as an anode lead portion. The resulting structure is shown in FIG. 9a is a schematic plan view, and FIG. 9b is a cross-sectional view taken along line AA ′.
Next, a glass cap was bonded with a thermosetting adhesive so as to cover the organic EL element portion and sealed (not shown).

Next, as shown in FIG. 10, a light reflecting layer 15 made of an aluminum vapor deposition film was formed on the surface of the substrate opposite to the side where the light emitting element was provided.
Then, the element 1B was obtained by optically polishing the light extraction end face to form a clean light extraction end face.

(Element of the present invention: edge-emitting organic EL element 1C)
An edge-emitting organic EL device 1C according to the present invention was produced as follows. Related figures are FIGS. 11-15.
The process until Comparative Example 1 was performed until the cathode electrode 14 was formed. However, as shown in FIG. 11, a glass substrate in which three end surfaces other than the light extraction end surface were previously tapered was used as the substrate. The taper processing was performed such that the end surface was brought into contact with the grindstone portion of the rotated glass polishing apparatus in a state where the substrate plane was inclined by 45 °, and the end surface had an angle of 45 ° with respect to the substrate plane. The grindstone portion of the polishing apparatus was a planar shape, and the end surface of the glass substrate was planar.
Next, an insulating layer 16 made of 1,3-bis (9-carbazolyl) benzene (mCP) for preventing short-circuiting between electrodes was formed by vacuum evaporation using an insulating layer evaporation mask having openings at predetermined positions. The resulting structure is shown in FIG. 12a is a schematic plan view, and FIG. 12b is a cross-sectional view along the line AA ′.
Next, a light reflecting layer 17 was formed by covering the lead-out portion of the transparent electrode and the portion of the transparent substrate not covered with the electrode with a 50 nm aluminum vapor deposition film. The resulting structure is shown in FIG. FIG. 13 a is a schematic plan view, and FIG. 13 b is a cross-sectional view along the line AA ′.
Next, a glass cap was bonded with a thermosetting adhesive so as to cover the organic EL element portion and sealed (not shown).
Next, as shown in FIG. 14, from 1,3-bis (9-carbazolyl) benzene (mCP) so as to cover the substrate surface opposite to the side where the light emitting element is provided and the end surface other than the light extraction end surface. An insulating layer 18 for preventing short-circuiting between electrodes was formed to a thickness of 100 nm by a vacuum deposition method.
Next, as shown in FIG. 15, a light reflection layer 15 made of an aluminum vapor deposition film was formed so as to cover the substrate surface opposite to the side where the light emitting element was provided and the end surface other than the light extraction end surface.
Next, the light extraction end face was optically polished to form a clean light extraction end face, thereby obtaining an element 1C.

2. Performance evaluation (evaluation of light leakage from other than the light extraction part)
"Measuring method"
A voltage was applied to the completed light emitting element, and it was visually confirmed whether there was leakage of light emission from other than the light extraction portion.
"result"
A voltage of 7 V was applied to the electrodes of the elements 1A, 1B, and 1C, and the state of light emission was confirmed. In the device 1C, no significant light leakage was observed from other than the light extraction end face. In the elements 1A and 1B, light leakage was observed at end faces other than the light extraction end face. Further, in the element 1A, light emission leakage was clearly observed also from the electrode terminal portion.

(Measurement of edge emission intensity)
"Measuring method"
A voltage of 7 V was applied to the element 1A, the element 1B, and the element 1C, and light emission from the end face was measured with a luminance meter.
"result"
Intensity of emission from the end face light extraction, the device 1A 1050 cd / ^{m 2,} the device 1B 1430cd / ^{m 2,} was the element 1C 2450cd / ^{m 2.} In the device of the present invention, light leakage from unintended portions is reduced, and the light emission intensity from the light extraction end face is improved.

Example 2
1. Preparation of edge-emitting inorganic EL element (preparation of edge-emitting inorganic EL element 2B)
An edge-emitting device 2B was produced in the same manner as in Example 1 except that the following inorganic EL device was used instead of the organic EL device 1B in Example 1.
<Inorganic EL layer>
A first insulating film made of tantalum pentoxide (Ta ₂ O ₅ ) is held at a substrate temperature of 200 ° C. and a pressure of 1 Pa so as to cover a part of the substrate, the stripe electrode, and the smoothing insulating layer. Then, sputtering was performed at a sputtering rate of 0.2 nm / sec at a high frequency power of 1 kW in an argon mixed gas atmosphere containing oxygen to form a film with a thickness of 200 nm. Next, a light emitting layer made of zinc sulfide (ZnS) to which 3 mol% of manganese (Mn) was added was similarly subjected to high-frequency sputtering in an argon mixed gas atmosphere containing hydrogen sulfide (H ₂ S) at a substrate temperature of 350 ° C. The film was formed with a film thickness of 400 nm. Next, a second insulating film made of tantalum pentoxide (Ta ₂ O ₅ ) was formed to a thickness of 200 nm in the same manner as the first insulating layer.
After the above layers were deposited on the substrate, heat treatment was performed at 400 ° C. for 1 hour in a vacuum of 10 ⁻⁴ Pa.

  Next, an inorganic EL element was fabricated by forming an upper electrode made of Al so as to cover the inorganic EL layer using an upper electrode deposition mask having an opening at a predetermined position.

  Next, after sealing as in Example 1, a reflective layer was deposited on the lead-out portion of the transparent electrode and the portion not covered with the electrode.

(Preparation of edge-emitting inorganic EL element 2C)
The element 2C was produced using the board | substrate which tapered the same end surface as Example 1C.
(Comparative element: Comparative Example 2)
For comparison, an element 2A was produced in which no evaporation was performed on the electrode terminal portion or the portion not covered with the electrode, and the end face was not tapered.

2. Performance evaluation (evaluation of light leakage from other than the light extraction part)
"Measuring method"
A voltage was applied to the completed light emitting element, and it was visually confirmed whether there was leakage of light emission from other than the light extraction portion.
"result"
An AC voltage of 150 V was applied to the electrodes of the elements 2A, 2B, and 2C, and the state of light emission was confirmed. In the element 2C, no significant light leakage was observed from other than the light extraction end face. In the elements 2A and 2B, light leakage was observed at end faces other than the light extraction end face. Furthermore, in the element 2A, light emission leakage was clearly observed also from the electrode terminal portion.

It is the schematic of the conventional end surface light emitting element. 1a: schematic plan view, 1b: schematic cross-sectional view taken along line A-A ' It is the B-B 'line cross-sectional schematic diagram of the conventional end surface light emitting element. 1 is a schematic cross-sectional view of a light emitting device of the present invention. 2a: schematic plan view, 2b: schematic cross-sectional view along line A-A ' It is a B-B 'line cross-sectional schematic diagram of the light emitting element of this invention. It is a cross-sectional schematic of the light emitting element of another aspect of this invention. 3a: schematic plan view, 3b: schematic cross-sectional view along line A-A ' It is a B-B 'line sectional schematic diagram of a light emitting element of another mode of the present invention. It is the schematic of the intermediate structure in the manufacturing process of the conventional end surface light emitting element. It is the schematic of the intermediate structure in the manufacturing process of the conventional end surface light emitting element. It is the schematic of the intermediate structure in the manufacturing process of the conventional end surface light emitting element. It is the schematic of the intermediate structure in the manufacturing process of the conventional end surface light emitting element. It is the schematic of the intermediate structure in the manufacturing process of the end surface light emitting element of an example by this invention. It is the schematic of the intermediate structure in the manufacturing process of the end surface light emitting element of an example by this invention. It is the schematic of the intermediate structure in the manufacturing process of the end surface light emitting element of an example by this invention. It is the schematic of the intermediate structure in the manufacturing process of the end surface light emitting element of another aspect by this invention. It is the schematic of the intermediate structure in the manufacturing process of the end surface light emitting element of another aspect by this invention. It is the schematic of the intermediate structure in the manufacturing process of the end surface light emitting element of another aspect by this invention. It is the schematic of the intermediate structure in the manufacturing process of the end surface light emitting element of another aspect by this invention. It is the schematic of the intermediate structure in the manufacturing process of the end surface light emitting element of another aspect by this invention.

Explanation of symbols

1: Light transmissive substrate 2: Light transmissive electrode (anode)
3: Organic functional layer 4: Non-transparent electrode (cathode)
5: Insulating layers 6, 7: Light reflecting layer 8: Insulating layer S: Light extraction end faces R1, R2, R3: End faces not intended for light extraction 11: Glass substrate 12: ITO electrode 12a: ITO electrode lead-out part 13: Organic EL Layer 14: Cathode 15: Light reflecting layer 16: Insulating layer 17: Light reflecting layer 18: Insulating layer

Claims (16)

  An edge-emitting light-emitting element that extracts light from a pair of electrodes on one plane of a light-transmitting substrate and at least one end surface of a laminated structure in which at least one light-emitting layer is sandwiched between the electrodes, An edge-emitting type comprising an electrode terminal portion on the plane, and at least one of a region not covered with the electrode on the plane of the substrate or the electrode terminal portion is covered with a light reflecting layer Light emitting element.   2. The edge-emitting light emitting device according to claim 1, wherein the electrode terminal portion is covered with a light reflecting layer.   2. The edge-emitting light emitting device according to claim 1, wherein a region not covered with the electrode is covered with a light reflecting layer.   2. The edge-emitting light emitting device according to claim 1, wherein the region not covered with the electrode and the electrode terminal portion are covered with a light reflecting layer.   5. The edge-emitting light-emitting element according to claim 1, wherein the light reflecting layer is conductive.   6. The edge-emitting light emitting device according to claim 1, wherein the electrode terminal covered with the light reflecting layer is a terminal of a transparent electrode.   The edge-emitting light emitting device according to claim 6, wherein the transparent electrode is indium tin oxide (ITO).   The edge-emitting light-emitting element according to claim 1, wherein the electrode terminal is a metal thin film.   9. The edge-emitting light-emitting element according to claim 1, wherein at least one of the end faces from which the light emission of the laminated structure is not taken out is covered with a light reflecting layer.   The angle formed by the end surface of the end surface covered with the light reflecting layer with respect to the surface of the substrate carrying the laminated structure or the surface opposite to the surface of the substrate carrying the laminated structure. 10. The edge-emitting light emitting device according to claim 9, wherein is an acute angle.   11. The edge-emitting light emitting device according to claim 9, wherein light emission is extracted from one end face of the multilayer structure, and an end face from which the other three light emission is not extracted is covered with a light reflecting layer. element.   12. The edge-emitting light emitting device according to claim 10, wherein an angle formed by the end face is 30 ° or more and 60 ° or less.   The edge-emitting light emitting device according to any one of claims 1 to 12, wherein the light reflecting layer contains aluminum, silver, gold, chromium, or an alloy thereof.   The edge-emitting light emitting device according to claim 13, wherein the light reflecting layer is a film formed by vapor deposition.   The edge-emitting light-emitting element according to claim 1, wherein the light-emitting element is an organic electroluminescence element.   The edge-emitting light-emitting element according to claim 1, wherein the light-emitting element is an inorganic electroluminescent element.

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