JP2007042488A - Organic electroluminescent element and exposure device as well as image forming apparatus using it - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic electroluminescent element which improves the reduction of the light emission area by a simple structure, has a long service life, and is excellent in mass productibility. <P>SOLUTION: The organic electroluminescent element comprises a plurality of light emitters each having a light emission layer formed of an organic material between an anode and a cathode, and partition walls which electrically separate the plurality of adjacent light emitters. A covering layer is provided which covers the whole surface including the light emitters and the partition walls. Ends of electrodes formed on the uppermost surface of the organic electroluminescent element are covered with the covering layer 8, thereby blocking the penetration paths of moisture, oxygen, etc. causing the reduction of the light emission area into the interior of the organic electroluminescent element, suppressing reduction of the light emission area, and providing an excellent long service life. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an organic electroluminescence element used as a light emitting element or the like in various apparatuses, an exposure apparatus using the same, and an image forming apparatus.

  Currently, active research is being conducted on organic electroluminescent elements having a functionally separated laminated structure in which an organic material is divided into a hole transport layer and a light emitting layer. In particular, high efficiency and long life, which are indispensable for the practical use of organic electroluminescence elements, have been sufficiently studied, and in recent years, displays using organic electroluminescence elements have been realized.

  Further, an image forming apparatus based on electrophotographic technology is an exposure apparatus for irradiating a photosensitive member uniformly charged at a predetermined potential with exposure light corresponding to image data and writing an electrostatic latent image on the photosensitive member. And an organic electroluminescence element is used as the light source.

  Here, the structure of the conventional general organic electroluminescent element is demonstrated using drawing.

  FIG. 8 is a cross-sectional view showing a configuration of a conventional electroluminescence element, and FIG. 9 is a cross-sectional view of a main part showing a structure of the conventional electroluminescence element.

As shown in FIG. 9, the organic electroluminescence element 30 includes an anode 32 made of a transparent conductive film such as ITO formed by sputtering or resistance heating vapor deposition on a substrate 31 made of glass or the like, N, N′-diphenyl-N, N′-bis (3-methylphenyl) -1,1′-diphenyl-4,4′-diamine (hereinafter referred to as “resistive heating vapor deposition method”) is formed on the anode 32 in the same manner. And a light emitting layer made of 8-hydroxyquinoline aluminum (hereinafter abbreviated as Alq ₃ ) formed on the hole transport layer 33 by resistance heating vapor deposition. 34 and a cathode 35 made of a metal film with a thickness of about 100 nm to 300 nm formed on the light emitting layer 34 by a resistance heating vapor deposition method or the like.

  When a positive direct current voltage or direct current is applied to the anode 32 of the organic electroluminescence element 30 having the above-described configuration and a negative direct current is applied to the cathode 35, holes are injected from the anode 32 into the light emitting layer 34 through the hole transport layer 33, Electrons are injected from the cathode 35 into the light emitting layer 34. In the light-emitting layer 34, recombination of holes and electrons occurs, and a light emission phenomenon occurs when excitons generated thereby shift from the excited state to the ground state.

  In such an organic electroluminescence element 30, normally, light emitted from the phosphor in the light emitting layer 34 is emitted in all directions around the phosphor, and the hole transport layer 33, anode 32, substrate Radiated into the air via 31. Alternatively, the light is once reflected in the direction opposite to the light extraction direction (substrate 31 direction), reflected by the cathode 35, and radiated into the air via the light emitting layer 34, the hole transport layer 33, the anode 32, and the substrate 31. The

  In addition, about the structure of an organic electroluminescent element, there exist some which are disclosed by (patent document 1), (patent document 2), etc.

  However, the organic substance constituting the organic electroluminescence element is easily affected by the solvent, and the metal having a small work function usually used for injecting electrons into the organic substance is easily deteriorated by moisture or oxygen. It was difficult to separate the organic electroluminescence element into a plurality of light emitting portions, and it was difficult to produce an organic electroluminescence element having fine light emitting pixels.

Therefore, as shown in FIG. 9, a pixel regulating layer 36 formed by forming an insulating layer such as polyimide on the anode 32 is provided between the light emitting portions 38 to be separated, and further formed on the anode 32. A partition wall 37 higher than the surface of the light emitting layer 34 and the cathode 35 and having a top width larger than the bottom width is formed on the pixel regulation layer 36, and the material of the light emitting layer 34 and the cathode 35 is vacuum-deposited to form a partition wall. The method of manufacturing the organic electroluminescence element 30 in which the material is not deposited on the shadow portion formed by the difference in the shape of the upper and lower sides of the layer 37 and the light emitting part 38 is separated, and the partition wall 37 is formed in a rectangular parallelepiped shape, A method for manufacturing an organic electroluminescence element in which the material of the cathode 35 is vacuum-deposited from an oblique direction so that the material is not deposited on the shadowed portion of the partition wall 37 and the light emitting portion 38 is separated is proposed. And that (Patent Document 3, Patent Document 4, Patent Document 5).
U.S. Pat. No. 5,917,280 US Pat. No. 5,932,895 JP-A-5-275172 Japanese Patent Application Laid-Open No. 5-258859 Japanese Patent Laid-Open No. 9-330792

  However, the above conventional techniques have the following problems.

  (1) The organic electroluminescence device has a problem with respect to the device lifetime, in which the light emitting area of the light emitting portion gradually decreases from the light emitting end portion with time after fabrication and eventually stops emitting light (hereinafter referred to as light emitting area reduction). Had.

  (2) When the light emitting part is separated by a partition wall or the like, the end of the electrode is present around the light emitting part, so that moisture, oxygen, etc. existing around the organic electroluminescence element are formed under the electrode and the organic There was a problem that it gradually entered the interface with the film from the periphery of the light-emitting pixel (light-emitting portion), deteriorated the electrode and the organic film, and reduced the light-emitting area.

  (3) By using an organic electroluminescence element as a light source in an exposure apparatus or the like of an image forming apparatus, the apparatus can be reduced in size and cost as compared with the laser beam system and LED array system, which are conventional exposure systems. However, each light-emitting pixel (light-emitting portion) of the organic electroluminescence element is minute, so even if the light-emitting area is reduced, the amount of emitted light is greatly reduced, and an image is formed on the photoreceptor. The required amount of light could not be obtained, and there was a problem of lacking in reliability and long life.

  The present invention solves the above-described conventional problems, and provides an organic electroluminescence device that can improve the occurrence of reduction of the light emitting area with a simple structure and has excellent long life and mass productivity, and is small and long-term using the same. An object of the present invention is to provide an exposure apparatus and an image forming apparatus excellent in practicality and reliability capable of obtaining a sufficient amount of light.

  In order to solve the above-described problems, an organic electroluminescent element of the present invention electrically connects a plurality of light emitting portions having a light emitting layer formed of an organic material between an anode and a cathode, and the adjacent light emitting portions. An organic electroluminescence element including a partition wall to be separated, and having a configuration including a coating layer covering the entire surface including the light-emitting portion and the partition wall.

  As a result, the ends of the electrodes formed on the uppermost surface of the organic electroluminescence element are all covered with the coating layer, and the infiltration path to the inside of the organic electroluminescence element, such as moisture and oxygen, which is the cause of the reduction of the light emitting area is reduced. It is possible to provide an organic electroluminescence device that can be cut off, can suppress a decrease in light emitting area, and has an excellent long life.

  In order to solve the above-described problems, an exposure apparatus of the present invention electrically separates a plurality of light emitting units having a light emitting layer formed of an organic material between an anode and a cathode and the plurality of adjacent light emitting units. The organic electroluminescent element provided with the coating layer provided on the whole surface including the said light emission part and the said partition is used for the light source.

  Thus, by using an organic electroluminescence element that suppresses a decrease in the light emitting area as a light source, an exposure apparatus excellent in practicality and reliability that can obtain a light amount necessary for long-term exposure without increasing the size of the apparatus. Can be provided.

  In order to solve the above problems, an image forming apparatus according to the present invention electrically separates a plurality of light emitting units having a light emitting layer formed of an organic material between an anode and a cathode and the plurality of adjacent light emitting units. And an organic electroluminescence element having a coating layer covering the entire surface including the light emitting portion and the partition.

  As a result, by using an organic electroluminescence element that suppresses a decrease in the light emitting area as a light source, it is possible to obtain an amount of light necessary for exposure over a long period of time without increasing the size of the apparatus. Can be provided.

  As described above, according to the organic electroluminescence element of the present invention, the exposure apparatus using the same, and the image forming apparatus, the following advantageous effects can be obtained.

According to the invention of claim 1,
(1) Since the coating layer is covered over the entire surface including the light emitting portion and the partition wall that electrically separates the plurality of adjacent light emitting portions, the end portion of the electrode formed on the uppermost surface of the organic electroluminescence element Organic electroluminescence with excellent long-life characteristics that can be covered with a coating layer, cut off the intrusion route of moisture, oxygen, etc. into the organic electroluminescence device, which is the cause of the reduction of the light emitting area, and suppress the reduction of the light emitting area. A luminescence element can be provided.

According to invention of Claim 2, in addition to the effect of Claim 1,
(1) Since the coating layer is formed of an insulator, it is possible to provide an organic electroluminescence element that is reliable and capable of reliably insulating a plurality of light emitting portions with high quality and excellent reliability.

According to invention of Claim 3, in addition to the effect of Claim 1 or 2,
(1) Since the coating layer is formed of a hygroscopic material, moisture that causes a reduction in the light emitting area can be absorbed by the coating layer, so that the amount of moisture entering the interface between the electrode and the light emitting layer can be reduced. It is possible to provide an organic electroluminescence element that is excellent in long-life property that can be reduced and the reduction of the light emitting area can be suppressed.

According to invention of Claim 4, in addition to the effect of any one of Claims 1 to 3,
(1) By forming the distance from the end of the partition wall to the end of the adjacent light emitting part to 5 μm to 10 μm, it is possible to delay the reduction of the light emitting area due to the ingress of moisture, oxygen, etc. An organic electroluminescence device can be provided.

According to the invention of claim 5, in addition to the effect of any one of claims 1 to 4,
(1) By forming the area of the electrode formed on the upper surface of the light emitting layer to be smaller than the area of the light emitting layer, the end of the electrode formed on the uppermost part can be reliably covered with the covering layer. In addition, it is possible to provide an organic electroluminescence device excellent in reliability and long life, which can cut off the intrusion route of moisture, oxygen, and the like, which cause a reduction in the light emitting area, and can suppress the reduction in the light emitting area.

According to invention of Claim 6, in addition to the effect of any one of Claims 1 to 4,
(1) Since the partition wall is formed of a material having water repellency, the light emitting layer and the partition wall can be formed apart from each other only by forming the light emitting layer by a wet film formation method. It is possible to provide an organic electroluminescence device excellent in mass productivity and long life that can delay the occurrence of a decrease in light emitting area due to penetration.

According to the invention of claim 7,
(1) By using an organic electroluminescence element that suppresses a decrease in light emitting area as a light source, an exposure apparatus excellent in practicality and reliability that can obtain a light amount necessary for exposure over a long period of time without increasing the size of the apparatus. Can be provided.

According to the invention described in claim 8,
(1) An image forming apparatus excellent in practicality and reliability capable of obtaining a light amount necessary for exposure over a long period of time without increasing the size of the apparatus by using an organic electroluminescence element that suppresses a decrease in light emitting area as a light source. Can be provided.

  The object of the present invention is to provide an organic electroluminescence device that can improve the occurrence of reduction of the light emitting area with a simple structure and has excellent long life and mass productivity. By covering the entire surface including the light emitting part and the partition wall of the organic electroluminescent element, the plurality of light emitting parts having a layer and a partition wall that electrically separates the plurality of adjacent light emitting parts. It was realized.

  A first invention made to solve the above problems is to electrically separate a plurality of light emitting portions having a light emitting layer formed of an organic material between an anode and a cathode and the plurality of adjacent light emitting portions. An organic electroluminescence device including a partition wall that includes a coating layer that covers the entire surface including the light-emitting portion and the partition wall.

  This configuration has the following effects.

  (1) Since the coating layer is covered over the entire surface including the light emitting portion and the partition wall that electrically separates the plurality of adjacent light emitting portions, the end portion of the electrode formed on the uppermost surface of the organic electroluminescence element All the covering layers are covered, and the infiltration path into the inside of the organic electroluminescence element such as moisture and oxygen, which is the cause of the reduction of the light emitting area, can be cut off, and the reduction of the light emitting area can be suppressed.

  Here, the substrate on which the light emitting portion of the organic electroluminescence element is formed only needs to have a strength capable of holding each layer formed on the substrate. In the case where the substrate side is used as a light extraction surface, the substrate is formed of a material having a transparency that does not hinder the visibility of transparent or translucent light emission. When the substrate side is not used as the light extraction surface, an opaque material can be used.

Specifically, transparent or translucent materials include soda-lime glass, barium / strontium-containing glass, lead glass, aluminosilicate glass, borosilicate glass, barium borosilicate glass, quartz glass, and other inorganic oxide glasses, inorganic Inorganic glass such as fluoride glass or polymer films such as polyethylene terephthalate, polycarbonate, polymethyl methacrylate, polyether sulfone, polyvinyl fluoride, polypropylene, polyethylene, polyacrylate, amorphous polyolefin, fluorine resin, etc. As ₂ Chalcogenoid glass such as S ₃ , As ₄₀ S ₁₀ , S ₄₀ Ge ₁₀ , metal oxide and nitride such as ZnO, Nb ₂ O, Ta ₂ O ₅ , SiO, Si ₃ N ₄ , HfO ₂ , TiO ₂ Etc. are preferably used.

  As the opaque material, a semiconductor material such as silicon, germanium, silicon carbide, gallium arsenide, or gallium nitride, or the above-described transparent substrate material containing a pigment or the like, or a metal material subjected to an insulation treatment on the surface is preferably used. It is done. Alternatively, a stacked substrate in which the above-described plurality of substrate materials are stacked can be used.

  Further, a circuit composed of a resistor, a capacitor, an inductor, a diode, a transistor, or the like for driving the organic electroluminescence element may be formed on the substrate surface or inside the substrate.

  Further, depending on the application, a material that transmits only a specific wavelength, a material that converts light of a specific wavelength having a light-light conversion function, or the like may be used. In addition, the substrate is preferably insulative, but is not particularly limited, and may have conductivity depending on a range that does not hinder driving of the organic electroluminescence element or an application.

As an anode, sputtering, resistance heating vapor deposition, etc. using ITO (indium tin oxide), IZO (indium zinc oxide), ATO (Sb doped SnO ₂ ), AZO (Al doped ZnO), etc. as members What is formed by is used suitably.
The material of the cathode is preferably a metal or alloy having a low work function, such as a metal such as Al, In, Mg, Ca, or Ti, a Mg alloy such as a Mg—Ag alloy or a Mg—In alloy, an Al—Li alloy, or an Al— An Al alloy such as a Ca alloy, an Al—Sr alloy, or an Al—Ba alloy is preferably used.
As the light emitting layer of the organic electroluminescence element, those having fluorescence or phosphorescence characteristics in the visible region and good film forming properties are preferable. In addition to Alq ₃ and Be-benzoquinolinol (BeBq ₂ ), 2,5- Bis (5,7-di-t-pentyl-2-benzoxazolyl) -1,3,4-thiadiazol, 4,4′-bis (5,7-benzyl-2-benzoxazolyl) Stilbene, 4,4′-bis [5,7-di- (2-methyl-2-butyl) -2-benzoxazolyl] stilbene, 2,5-bis (5,7-di-t-benzyl- 2-benzoxazolyl) thiophene, 2,5-bis [(5-α, α-dimethylbenzyl) -2-benzoxazolyl] thiophene, 2,5-bis [5,7-di- (2- Methyl-2-butyl) -2-benzoxazolyl]- , 4-diphenylthiophene, 2,5-bis (5-methyl-2-benzoxazolyl) thiophene, 4,4′-bis (2-benzoxazolyl) biphenyl, 5-methyl-2- [2- Benzoxazole series such as [4- (5-methyl-2-benzoxazolyl) phenyl] vinyl] benzoxazolyl, 2- [2- (4-chlorophenyl) vinyl] naphtho [1,2-d] oxazole Benzothiazoles such as 2,2 ′-(p-phenylenedivinylene) -bisbenzothiazole, 2- [2- [4- (2-benzimidazolyl) phenyl] vinyl] benzimidazole, 2- [2- (4 -Carboxyphenyl) vinyl] fluorescent brighteners such as benzimidazole such as benzimidazole, tris (8-quinolinol) aluminum, bis (8-chi Linole) magnesium, bis (benzo [f] -8-quinolinol) zinc, bis (2-methyl-8-quinolinolato) aluminum oxide, tris (8-quinolinol) indium, tris (5-methyl-8-quinolinol) aluminum, 8-hydroxy such as 8-quinolinol lithium, tris (5-chloro-8-quinolinol) gallium, bis (5-chloro-8-quinolinol) calcium, poly [zinc-bis (8-hydroxy-5-quinolinyl) methane] Metal chelated oxinoid compounds such as quinoline-based metal complexes and dilithium ependridione, 1,4-bis (2-methylstyryl) benzene, 1,4- (3-methylstyryl) benzene, 1,4-bis ( 4-methylstyryl) benzene, distyrylbenzene, 1,4-bis ( -Styrylbenzene compounds such as ethylstyryl) benzene, 1,4-bis (3-ethylstyryl) benzene, 1,4-bis (2-methylstyryl) 2-methylbenzene, and 2,5-bis (4- Methylstyryl) pyrazine, 2,5-bis (4-ethylstyryl) pyrazine, 2,5-bis [2- (1-naphthyl) vinyl] pyrazine, 2,5-bis (4-methoxystyryl) pyrazine, 2, Distylpyrazine derivatives such as 5-bis [2- (4-biphenyl) vinyl] pyrazine, 2,5-bis [2- (1-pyrenyl) vinyl] pyrazine, naphthalimide derivatives, perylene derivatives, oxadiazole derivatives, Ardazine derivatives, cyclopentadiene derivatives, styrylamine derivatives, coumarin derivatives, aromatic dimethylidin derivatives, etc. are preferably used. . Furthermore, anthracene, salicylate, pyrene, coronene and the like are also used.

  The light emitting layer may be sandwiched between an anode and a cathode as a single layer structure, or a two layer structure having a hole transport layer on the anode side of the light emitting layer, a two layer structure having an electron transport layer on the cathode side of the light emitting layer, A three-layer structure having a hole transport layer on the anode side of the light emitting layer and an electron transport layer on the cathode side may be employed.

  When having a hole transport layer, holes from the anode can be efficiently transported to the light emitting layer, and when having an electron transport layer, electrons can be smoothly transferred to the light emitting layer and enter the light emitting layer. It is possible to prevent holes from moving to the electron transport layer.

  As a material for the hole transport layer, a material having high hole mobility, transparent and good film forming property is preferable. In addition to TPD, porphyrins such as porphyrin, tetraphenylporphyrin copper, phthalocyanine, copper phthalocyanine, and titanium phthalocyanine oxide are used. Compound, 1,1-bis {4- (di-P-tolylamino) phenyl} cyclohexane, 4,4 ′, 4 ″ -trimethyltriphenylamine, N, N, N ′, N′-tetrakis (P-tolyl) ) -P-phenylenediamine, 1- (N, N-di-P-tolylamino) naphthalene, 4,4′-bis (dimethylamino) -2-2′-dimethyltriphenylmethane, N, N, N ′, N′-tetraphenyl-4,4′-diaminobiphenyl, N, N′-diphenyl-N, N′-di-m-tolyl-4,4′-diaminobiphenyl, N-phenyl Aromatic tertiary amines such as enylcarbazol, 4-di-P-tolylaminostilbene, 4- (di-P-tolylamino) -4 ′-[4- (di-P-tolylamino) styryl] stilbene, etc. Stilbene compounds, triazole derivatives, oxadiazole derivatives, imidazole derivatives and polyarylalkane derivatives, pyrazoline derivatives, pyrazolone derivatives and phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives Organic materials such as silazane derivatives, polysilane aniline copolymers, polymer oligomers, styrylamine compounds, aromatic dimethylidin compounds, and poly-3-methylthiophene are preferably used. Further, a polymer-dispersed hole transport layer in which a low-molecular organic material for hole transport is dispersed in a polymer such as polycarbonate is also used. Furthermore, these hole transport materials can also be used as a hole injection material or an electron block material.

  Examples of the material for the electron transport layer include oxadiazole derivatives such as 1,3-bis (4-tert-butylphenyl-1,3,4-oxadiazolyl) phenylene (OXD-7), anthracene derivatives, and diphenylquinone derivatives. Preferably used. These electron transport materials can also be used as an electron injection material or a hole blocking material.

A pixel regulating layer is formed on the anode in order to electrically isolate a plurality of light emitting portions of the organic electroluminescence element and regulate the pixel. A portion that is a window without a pixel regulating layer is a light emitting portion, which functions as a light emitting element. As a material for forming the pixel regulation layer, any material having insulating properties may be used. Specific examples include metal oxides and metal nitrides such as SiO ₂ , MgO, Al ₂ O ₃ , and Cr ₂ O ₃ , and further carbides and sulfides. Alternatively, a resin capable of film formation patterning represented by polyimide, acrylic, polycarbonate, polyester, polyethylene, polypropylene, or the like may be used.

  The partition wall may have any structure as long as the light emitting portion can be formed separately, and the partition wall structure, reverse taper structure, overhang structure, undercut structure, and the like that have been conventionally proposed are preferably used.

  As a material for the partition wall, an insulating negative resist, a positive resist, a combination of a negative resist and a positive resist, or a combination of a resist and an inorganic thin film is preferably used. Further, a conductive material may be used as long as the risk of short circuit with the electrode can be avoided. Note that the thickness of the partition wall is preferably larger than the combined thickness of the light emitting layer and the electrode formed on the light emitting layer. This makes it possible to reliably separate the electrodes formed on the light emitting layer.

  As a material for forming the coating layer, any material may be used as long as it has insulating properties and excellent gas barrier properties.

  By adding an inert gas such as Ar gas when forming the coating layer, the mean free path (mean free path) can be shortened to improve the step coverage, and the partition wall formed in a reverse taper shape or the like The base part and the side surface of can be covered with a covering layer. Thereby, since the edge part of an electrode can be completely covered with a coating layer, the penetration | invasion path | routes, such as a water | moisture content and oxygen, can be interrupted | blocked reliably, and generation | occurrence | production of a light emission area reduction can be suppressed.

  A second invention made to solve the above problems is the organic electroluminescence element according to the first invention, wherein the coating layer is formed of an insulator.

  With this configuration, in addition to the operation of the first invention, the following operation is provided.

  (1) Since the coating layer is formed of an insulator, a plurality of light emitting portions can be reliably insulated.

Here, as a material for forming the coating layer, metal oxides such as SiO ₂ , MgO, Al ₂ O ₃ , Cr ₂ O ₃ , metal nitrides, carbides, sulfides, and the like are preferably used. Moreover, the resin which can be apply | coated represented by a polyimide, an acryl, a polycarbonate, polyester, polyethylene, a polypropylene etc. can also be used. In particular, a metal oxide or the like is preferable because it can be formed under a relatively mild condition without returning to atmospheric pressure after forming an electrode in a vacuum on the light emitting layer.

  A third invention made to solve the above problems is the organic electroluminescence element according to the first or second invention, wherein the coating layer is made of a hygroscopic material. is doing.

  With this configuration, in addition to the operation of the first or second invention, the following operation is provided.

  (1) Since the coating layer is formed of a hygroscopic material, moisture that causes a reduction in the light emitting area can be absorbed by the coating layer, so that the amount of moisture entering the interface between the electrode and the light emitting layer And the reduction of the light emitting area can be suppressed.

  Here, as the material of the coating layer, calcium oxide or the like is preferably used.

  A fourth invention made to solve the above-described problem is the organic electroluminescence element according to any one of the first to third inventions, wherein the light emitting unit is adjacent to an end of the partition wall. The distance to the edge part of this is 5 μm to 10 μm.

  With this configuration, in addition to the operation of any one of the first to third inventions, the following operation is provided.

(1) By forming the distance from the end portion of the partition wall to the end portion of the adjacent light emitting portion to 5 μm to 10 μm, it is possible to delay the generation of the light emitting area due to the intrusion of moisture or oxygen.
.

  Here, as the distance from the end of the partition to the end of the adjacent light emitting unit becomes shorter than 5 μm, the emission area is likely to decrease in a short time, and the effect of separating the partition from the light emitting unit is insufficient. As the distance becomes longer than 10 μm, there is a tendency that the area of the light emitting portion becomes insufficient and the light amount decreases, or the pitch of the light emitting portions becomes coarse and the resolution decreases, both of which are not preferable.

  A fifth invention made to solve the above problems is the organic electroluminescence element according to any one of the first to fourth inventions, wherein the anode is formed on an upper surface of the light emitting layer. Alternatively, either one of the cathodes has a configuration having an area smaller than the area of the light emitting layer.

  With this configuration, in addition to the operation of any one of the first to fourth inventions, the following operation is provided.

  (1) Since either the anode or the cathode formed on the upper surface of the light emitting layer has an area smaller than the area of the light emitting layer, the end of the electrode formed on the uppermost portion is reliably covered with the covering layer. And the intrusion route of moisture, oxygen, or the like that causes a reduction in the light emitting area can be cut off, and the reduction in the light emitting area can be effectively suppressed.

  A sixth invention made to solve the above-mentioned problems is the organic electroluminescence element according to any one of the first to fifth inventions, wherein the partition is formed of a material having water repellency. It has the composition which is.

  With this configuration, in addition to the operation of any one of the first to fifth inventions, the following operation is provided.

  (1) Since the partition wall is formed of a material having water repellency, the light emitting layer and the partition wall can be formed apart from each other only by forming the light emitting layer by a wet film forming method. It is possible to delay the occurrence of light emission area reduction due to intrusion, and it is excellent in mass productivity and long life.

  Here, when the light emitting layer is formed by a wet film forming method such as a spin coat method, the light emitting layer is formed by being submerged to the base of the partition wall. Can be kept inside the light emitting section. The same effect can be obtained when the pixel regulation layer has water repellency.

  7th invention made | formed in order to solve the said subject is exposure apparatus, Comprising: It has the structure which used the organic electroluminescent element of any one of 1st thru | or 6 for the light source. .

  This configuration has the following effects.

  (1) By using an organic electroluminescence element that suppresses a decrease in light emitting area as a light source, a light amount necessary for exposure can be obtained over a long period of time without increasing the size of the apparatus, and the utility and reliability are excellent.

  An eighth invention made to solve the above problems is an image forming apparatus having a configuration in which the organic electroluminescence element according to any one of the first to sixth aspects is used as a light source. Yes.

  This configuration has the following effects.

  (1) By using an organic electroluminescence element that suppresses a decrease in light emitting area as a light source, a light amount necessary for exposure can be obtained over a long period of time without increasing the size of the apparatus, and the utility and reliability are excellent.

  Here, the organic electroluminescence element is mounted on the exposure unit of the image forming apparatus. An organic electroluminescence element mounted as a light source on the head support member of the exposure unit is hermetically sealed by a sealing material, and is supplied with a voltage corresponding to image data from a driver disposed on the head support member and emits light. To do. Irradiation light from the organic electroluminescence element is refracted by a prism, condensed by a fiber array, and further narrowed down in a sub-scanning direction by a cylindrical lens, and used for exposure.

(Embodiment 1)
The organic electroluminescent element in Embodiment 1 of this invention is demonstrated based on drawing.

  FIG. 1 is a cross-sectional view of a principal part showing the structure of an organic electroluminescence element according to Embodiment 1 of the present invention.

  In FIG. 1, 1 is the organic electroluminescent element in Embodiment 1 of the present invention, 2 is the substrate of the organic electroluminescent element 1 formed of transparent soda glass, and 3 is a transparent conductive thin film such as ITO on the substrate 2 A transparent anode formed by forming a film 4, a pixel regulating layer 4 formed by depositing an insulating layer such as polyimide on the anode 3, and a negative electrode 5, which is formed of a negative resist on the pixel regulating layer 4 and will be described later. 7 is a partition wall for separating 7, 6 is on the anode 3, a part on the pixel regulation layer 4, the light emitting layer of the organic electroluminescence element 1 formed on the partition wall 5, and 7 is formed on the light emitting layer 6 by vacuum deposition. The cathode 8 is formed by covering the entire surface of the organic electroluminescent element 1 including the partition wall 5 as a barrier layer, and 9 is partially removed by removing the pixel regulating layer 4 formed on the anode 3. Formation The a light emitting portion of the organic electroluminescence element 1.

  In the present embodiment, the light emitted from the light emitting unit 9 is extracted from the substrate 2 side, but may be extracted from the cathode 7 side opposite to the substrate 2 or the side surface of the substrate 2.

  The manufacturing method of the organic electroluminescent element comprised as mentioned above is demonstrated.

  First, an ITO film having a thickness of 150 nm is formed on the substrate 2 by sputtering, a positive resist is applied on the ITO film by spin coating, etc., prebaked for a predetermined time, and then exposed to a predetermined pattern. Then, development is performed by dipping in a resist developer. Then, after performing a post-bake for a predetermined time, the transparent conductive film is patterned by immersing in an ITO etchant for a predetermined time, and the resist is stripped from the ITO film using a resist stripper. Thus, the anode 3 was formed in a predetermined pattern.

  Next, after forming an insulating layer as a pixel regulating layer 4 on the anode 3, only a portion that functions as a light emitting element is removed to form a light emitting portion 9. In this embodiment mode, photosensitive polyimide is formed by a spin coating method. After film formation, prebaking was performed on a hot plate for a predetermined time, and then exposure was performed to a predetermined pattern, and development was performed by immersing in a resist developer. As a result, the light emitting portion 9 functioning as a light emitting element was formed in a window shape surrounded by the pixel regulating layer 4. Next, post-baking was performed to completely cure at a high temperature so that the light emitting part 9 would not be deformed by being attacked by a solvent or a reagent used in a later step.

  Next, a partition wall 5 for separating a cathode 7 to be formed later was formed on the pixel regulating layer 4. In this embodiment, a negative resist is used as the partition wall material. First, a negative resist was formed on the pixel regulation layer 4 by spin coating. At this time, the film thickness of the negative resist was made thicker than the combined thickness of the light emitting layer 6 and the cathode 7 formed on the anode 3. As a result, the cathode 7 to be formed later can be separated. After forming a negative resist, pre-bake on a hot plate for a predetermined time, expose to a predetermined pattern, and pre-bake on the hot plate for a predetermined time again to accelerate curing and use a resist developer. Development was performed by dipping. As a result, the partition wall 5 having an insulating reverse taper shape was formed on the pixel regulation layer 4. Next, post-baking was performed to completely cure at a high temperature so that the reverse-tapered partition walls 5 were not deformed by being attacked by a solvent or a reagent used in a later step. Further, the difference between the width of the bottom portion and the width of the top portion of the inversely tapered shape is greatly influenced by the prebaking temperature and time, the exposure amount, the development time, and the like. In particular, the temperature is preferably controlled so as to be uniform over the entire substrate 2.

  The distance between the partition wall 5 and the end of the light emitting unit 9 was 5 μm to 10 μm. As the distance from the end of the partition wall 5 to the end of the adjacent light emitting unit 9 becomes shorter than 5 μm, the light emission area tends to decrease in a short time, and the effect of separating the partition wall 5 from the light emitting unit 9 is insufficient. It was found that as the distance becomes longer than 10 μm, the area of the light-emitting portion 9 becomes insufficient and the amount of light decreases, or the pitch of the light-emitting portions 9 becomes rough and the resolution tends to decrease. It is. By setting the distance between the partition wall 5 which is an infiltration path of moisture, oxygen and the like and the end of the light emitting part 9 to 5 μm or more, a sufficient distance can be provided for the growth rate of the light emitting area reduction (approximately 0.01 μm / hour) Can be secured.

  Next, the light emitting layer 6 was formed by a film forming method such as a vacuum evaporation method or a spin coating method, and the cathode 7 was formed by a vacuum evaporation method. When the cathode 7 is deposited, it is preferable to deposit an inert gas such as Ar gas. Thereby, the mean free path (mean free path) can be shortened, and step coverage can be improved. As a result, the end portion of the cathode 7 sinks into the shadow (root portion) of the reverse taper portion of the partition wall 5 and the distance between the end portion of the light emitting portion 9 and the end portion of the cathode 7 is increased. The penetration path can be lengthened, and the effect of suppressing the occurrence of a reduction in the light emitting area can be obtained.

  Further, when the light emitting layer 6 is formed by a vacuum deposition method, if the mean free path is made shorter than that and the cathode 7 is vacuum deposited, the light emitting layer 6 itself can be completely covered by the cathode 7, Since the organic film forming the light emitting layer 6 is not exposed, the intrusion of moisture, oxygen and the like can be suppressed, and the effect of suppressing the reduction of the light emitting area can be obtained. In addition, when using a vacuum evaporation method for film-forming of the light emitting layer 6, it is preferable to form the cathode 7 continuously, without breaking a vacuum.

  Next, the coating layer 8 was formed as a barrier layer without returning to atmospheric pressure. The coating layer 8 was formed so as to cover all the shadows and side surfaces of the reverse tapered portion of the partition wall 5. Thereby, the edge part of the cathode 7 can be completely covered with the coating layer 8 without a defect, and the effect which suppresses generation | occurrence | production of a light emission area reduction by interrupting | blocking the penetration | invasion path | route of a water | moisture content, oxygen, etc. reliably is acquired.

  In the present embodiment, the coating layer 8 is formed by a relatively mild vacuum deposition method without returning to the atmospheric pressure after the cathode 7 is formed by a vacuum deposition method. At this time, by introducing an inert gas such as Ar gas as in the film formation of the cathode 7, the mean free path (mean free path) can be shortened to improve the step coverage. The shadow and side of the reverse taper portion can be completely covered.

  In addition, when calcium oxide etc. which have water absorption are used as a material of the coating layer 8, the moisture which permeates can be captured and generation | occurrence | production of a light emission area reduction can be suppressed more effectively.

  An image forming apparatus using the organic electroluminescence element according to Embodiment 1 formed as described above will be described.

  FIG. 2 is a schematic cross-sectional view showing a main part of an image forming apparatus using the organic electroluminescence element according to Embodiment 1 of the present invention.

  In FIG. 2, 10 is a color image forming apparatus, and 11 is an image forming apparatus 10 for forming toner images of yellow (Y), magenta (M), cyan (C), and black (K) in order from the bottom. The four developing units, 12 are exposure units (exposure devices) of the image forming apparatus 10 using the organic electroluminescence element 1 according to the first embodiment as a light source, which are arranged corresponding to the developing units 11 of the respective colors. Is a photosensitive portion of the image forming apparatus 10 arranged corresponding to each of the developing unit 11 and the exposure unit 12 of each color, and 14 is arranged at a position facing the developing unit 11, the exposure unit 12 and the photosensitive unit 13 of each color. Each color toner image visualized on the photosensitive drum 13a of each color photosensitive section 13 is transferred onto the recording medium 20 to form a color toner image by superimposing them on the recording medium 20, and the transfer section 14a of each color Photosensitive drum 13b is a transfer roller of the transfer section 14, 14b is a spring of the transfer section 14 that presses each transfer roller 14a against the photosensitive drum 13a of each color, and 15 is a developing section 11, an exposure section 12, and a photosensitive section. 13 is a sheet feeding unit of the image forming apparatus 10 that is disposed on the opposite side of the transfer unit 14 with the recording medium 20 interposed therebetween, 16 is a sheet feeding roller that takes out the recording medium 20 from the sheet feeding unit 15 one by one, 17 Is a registration roller that is arranged on a paper conveyance path from the paper supply unit 15 to the transfer unit 14 and sends the recording medium 20 to the transfer unit 14 at a predetermined timing. 18 is a recording medium on which a color toner image is formed by the transfer unit 14 The fixing unit 18a of the image forming apparatus 10 disposed on the paper transport path 20 travels, and the color image transferred onto the recording medium 20 is heated by nipping and rotating the recording medium 20 together with the pressing roller 18b. Heating roller of the fixing unit 18 that fixes to wear, 19 is a discharge tray of the image forming apparatus 10 that the recording medium 20 on which the color image forming has been completed is discharged.

  Next, details of the developing unit 11 of the image forming apparatus 10 will be described. FIG. 3 is a schematic cross-sectional view of an essential part showing a developing unit of the image forming apparatus.

  In FIG. 3, reference numeral 11a denotes a developing roller (development) that attaches toner to the photosensitive drum 13a on which the electrostatic latent image is formed on the outer peripheral surface by the irradiation light from the exposure unit 12 and visualizes the electrostatic latent image as a toner image. Means 11b, a stirring member for stirring the toner 21 in the tank, 11c a supply roller for stirring the toner 21 and supplying it to the developing roller 11a, and 11d for the toner 21 supplied to the developing roller 11a having a predetermined thickness. And a doctor blade that charges the toner 21 by friction.

  Next, details of the exposure unit 12 of the image forming apparatus 10 will be described. FIG. 4 is a schematic cross-sectional view of an essential part showing an exposure unit of the image forming apparatus.

  In FIG. 4, 12a is a head support member of the exposure unit 12, 12b is a sealing material for hermetically sealing the organic electroluminescence element 1 according to Embodiment 1 mounted as a light source on the head support member 12a, and 12c is a head support. A driver which is arranged on the member 12a and supplies a voltage corresponding to image data to the organic electroluminescence element 1 to emit light, 12d is a prism which refracts the irradiation light from the organic electroluminescence element 1, and 12e is from the prism 12d. 12f is a cylindrical lens that narrows the light from the fiber array 12e in the sub-scanning direction, and an arrow indicates an optical path.

  The organic electroluminescence element 1 may be driven by an AC voltage, an AC current, or a pulse wave in addition to the DC drive.

  Next, details of the photosensitive unit 13 of the image forming apparatus 10 will be described. FIG. 5 is a schematic cross-sectional view of an essential part showing a photosensitive portion of the image forming apparatus.

  In FIG. 5, reference numeral 13 a denotes a photosensitive drum (photosensitive body) as an image carrier disposed rotatably, and reference numeral 13 b denotes a charging device (which is pressed against the photosensitive drum 13 a to charge the surface of the photosensitive drum 13 a to a uniform potential ( Charging means 13c is a cleaner for removing the toner remaining on the photosensitive drum 13a after the image transfer.

  The photosensitive drums 13a of the photosensitive portions 13 corresponding to the respective colors are arranged in a line so that the rotation center axes are aligned on the same straight line. The charger 13b pressed against the photosensitive drum 13a rotates following the rotation of the photosensitive drum 13a.

  The operation of the image forming apparatus 10 configured as described above will be described.

  A latent image of the yellow component color of the image information is formed on the lowermost photosensitive drum 13a corresponding to yellow. This latent image is visualized as a yellow toner image on the photosensitive drum 13a by the lowermost developing roller 11a having yellow toner. Meanwhile, the recording medium 20 taken out from the paper supply unit 15 by the paper supply roller 16 is sent to the transfer unit 14 at a timing by the registration roller 17. Then, it is nipped and conveyed between the photosensitive drum 13a and the transfer roller 14a, and at this time, the above-described yellow toner image is transferred from the photosensitive drum 13a.

  While the yellow toner image is transferred to the recording medium 20, a magenta component color latent image is subsequently formed, and the magenta toner image made of magenta toner is visualized on the second photosensitive drum 13a from the bottom. Then, the magenta toner image and the yellow toner image are transferred onto the recording medium 20 to which the yellow toner image has been transferred.

  Thereafter, image formation and transfer are similarly performed for the cyan toner image and the black toner image, and the superposition of the four color toner images on the recording medium 20 is completed.

  Thereafter, the recording medium 20 on which the color image is formed is conveyed to the fixing unit 18. In the fixing unit 18, the transferred toner image is heat-fixed on the recording medium 20, and a full-color image is formed on the recording medium 20.

  The recording medium 20 on which a series of color image formation has been completed in this manner is then discharged onto the paper discharge tray 28.

  The order of superimposing the four color toner images is not limited to that described above, and can be arbitrarily selected. The development colors are also limited to four colors of yellow, magenta, cyan and black. is not. Further, the image forming apparatus is not limited to the one corresponding to the full color, and can be applied to a single color image forming apparatus such as black.

  As described above, the organic electroluminescence element according to Embodiment 1 of the present invention has the following effects.

  (1) Since the coating layer 8 is provided over the entire surface including the partition wall 5 that electrically separates a plurality of adjacent light emitting portions 9, the end of the cathode 7 formed on the uppermost surface of the organic electroluminescence element 1 All the portions are covered with the coating layer 8, and the intrusion path into the inside of the organic electroluminescence element 1 such as moisture and oxygen which is the cause of the reduction of the light emitting area can be cut off, and the reduction of the light emitting area can be suppressed.

  (2) Since the coating layer 8 is formed of an insulator, the plurality of light emitting portions 9 can be reliably insulated.

  (3) Since the coating layer 8 has a hygroscopic property, the coating layer 8 can absorb moisture that causes a reduction in the light emitting area, so that the amount of moisture entering the interface between the cathode 7 and the light emitting layer 6 is reduced. And reduction of the light emitting area can be suppressed.

  (4) By forming the distance from the end portion of the partition wall 5 to the end portion of the adjacent light emitting portion 9 to 5 μm to 10 μm, it is possible to delay the occurrence of a decrease in the light emitting area due to intrusion of moisture, oxygen, or the like.

  As described above, the image forming apparatus using the organic electroluminescence element according to Embodiment 1 of the present invention has the following effects.

  (1) By using an organic electroluminescence element that suppresses a decrease in light emitting area as a light source, a light amount necessary for exposure can be obtained over a long period of time without increasing the size of the apparatus, and the utility and reliability are excellent.

(Embodiment 2)
The organic electroluminescent element in Embodiment 2 of this invention is demonstrated based on drawing.

  FIG. 6 is a cross-sectional view showing the main part of the structure of the organic electroluminescence element according to Embodiment 2 of the present invention.

  In FIG. 6, the organic electroluminescent element 1a in the second embodiment is different from the organic electroluminescent element 1 in the first embodiment in that the end of the light emitting layer 6 is formed up to the vicinity of the end of the base of the adjacent partition wall 5. And the cathode 7 formed on the upper surface of the light emitting layer 6 has a smaller area than the area of the light emitting layer 6.

  About the manufacturing process of the organic electroluminescent element 1a in Embodiment 2 comprised as mentioned above, since the manufacturing process of the partition 5 is the same as that of the manufacturing process of the organic electroluminescent element 1 in Embodiment 1, it The subsequent steps will be described.

  After the partition wall 5 was formed, the light emitting layer 6 was formed by a wet film forming method such as a spin coating method. At this time, the end portion of the light emitting layer 6 sinks to the root portion of the inversely tapered partition wall 5, and the film is formed to the vicinity of the end portion of the partition wall 5.

  Next, the cathode 7 was formed by vacuum deposition. As for the formation of the cathode 7, as in the first embodiment, an inert gas such as Ar gas is introduced at the time of film formation, so that the end of the cathode 7 can be embedded into the base of the reverse taper portion of the partition wall 5. . Since the distance from the end of the light emitting unit 9 to the end of the cathode 7 is increased, the effect of suppressing the occurrence of a decrease in the light emitting area can be obtained as in the first embodiment.

  Since the end of the light emitting layer 6 reaches the vicinity of the end of the partition wall 5, the area of the cathode 7 is smaller than the area of the light emitting layer 6, and there is a portion where the light emitting layer 6 cannot be completely covered by the cathode 7. Although it occurs, the end portion of the light emitting layer 6 exposed by the covering layer 8 can be directly covered by forming the covering layer 8 in the subsequent process as in the first embodiment, and the intrusion path of moisture, oxygen, and the like can be covered. Can be shut off reliably.

  As described above, the organic electroluminescence element according to the second embodiment of the present invention has the following actions in addition to the actions of the first embodiment.

  (1) Since the cathode 7 formed on the upper surface of the light emitting layer 6 has an area smaller than the area of the light emitting layer 6, the end portion of the cathode 7 formed on the top is reliably covered with the coating layer 8. It is possible to cut off the intrusion route of moisture, oxygen, etc., which causes a decrease in the light emitting area, and effectively suppress the decrease in the light emitting area.

(Embodiment 3)
The organic electroluminescent element in Embodiment 3 of this invention is demonstrated based on drawing.

  FIG. 7 is a cross-sectional view showing the main part of the structure of the organic electroluminescence element according to Embodiment 3 of the present invention.

  In FIG. 7, the organic electroluminescent element 1b in the third embodiment is different from the organic electroluminescent element 1 in the first embodiment in that a material having water repellency is used for the material of the pixel regulating layer 4 and the partition wall 5, and the light emitting layer 6 is a point formed only on the anode 3.

  Regarding the manufacturing process of the organic electroluminescence element 1b according to the third embodiment configured as described above, only the material of the pixel regulating layer 4 and the partition wall 5 is different, and the manufacturing process of the partition wall 5 is the same as that in the first embodiment. Since it is the same as the manufacturing process of the electroluminescent element 1, the subsequent processes will be described.

  After the partition wall 5 was formed, the light emitting layer 6 was formed by a wet film forming method such as a spin coating method as in the second embodiment. At this time, the pixel regulation layer 4 and the partition walls 5 have water repellency, so that the range in which the light emitting layer 6 is formed remains inside the light emitting unit 9.

  Next, the cathode 7 was formed by vacuum vapor deposition as in the first and second embodiments. Since the light emitting layer 6 is formed only on the anode 3 and the periphery thereof is surrounded by the pixel regulating layer 4, when the cathode 7 is vacuum-deposited, the light emitting layer 6 itself can be completely covered with the cathode 7, and light emission The layer 6 is not exposed, and entry of moisture, oxygen, and the like into the light emitting layer 6 can be effectively suppressed.

  Furthermore, by forming the covering layer 8 as in the first and second embodiments, the entire surface of the cathode 7 can be covered with the covering layer 8, and the intrusion path of moisture, oxygen, or the like can be reliably blocked.

  As described above, the organic electroluminescence element according to the third embodiment of the present invention has the following actions in addition to the actions of the first and second embodiments.

  (1) Since the pixel regulating layer 4 and the partition wall 5 are formed of a material having water repellency, the light emitting layer 6 and the partition wall 5 are formed apart from each other only by forming the light emitting layer 6 by a wet film forming method. It is possible to delay the occurrence of a decrease in light emitting area due to the intrusion of moisture, oxygen, etc., and it is excellent in mass productivity and long life.

  According to the present invention, it is possible to improve the occurrence of a decrease in the light emitting area with a simple structure, provide an organic electroluminescence element excellent in long life and mass productivity, and is useful as a light emitting element in various devices. By using it as a light source for an exposure apparatus or an image forming apparatus, it is possible to obtain a light amount necessary for exposure without increasing the size of the apparatus, and it is excellent in practicality and reliability.

Sectional drawing which shows the principal part which shows the structure of the organic electroluminescent element in Embodiment 1 of this invention 1 is a schematic cross-sectional view of a main part showing an image forming apparatus using an organic electroluminescence element according to Embodiment 1 of the present invention. Cross-sectional schematic diagram of the main part showing the developing unit of the image forming apparatus Cross-sectional schematic diagram of the main part showing the exposure part of the image forming apparatus Cross-sectional schematic diagram of the relevant part showing the photosensitive part of the image forming apparatus Sectional drawing which shows the principal part which shows the structure of the organic electroluminescent element in Embodiment 2 of this invention Sectional drawing which shows the principal part which shows the structure of the organic electroluminescent element in Embodiment 3 of this invention Sectional drawing which shows the structure of the conventional electroluminescent element Cross-sectional view of the main part showing the structure of a conventional electroluminescence element

Explanation of symbols

1, 1a, 1b, 30, 30a Organic electroluminescence element 2, 31 Substrate 3, 32 Anode 4, 36 Pixel regulating layer 5, 37 Partition 6, 34 Light emitting layer 7, 35 Cathode 8 Cover layer 9, 38 Light emitting part 10 Image Forming device 11 Developing section 11a Developing roller (developing means)
11b Stirring member 11c Supply roller 11d Doctor blade 12 Exposure part 12a Head support member 12b Sealing material 12c Driver 12d Prism 12e Fiber array 12f Cylindrical lens 13 Photosensitive part 13a Photosensitive drum 13b Charger (charging means)
13c Cleaner 14 Transfer section 14a Transfer roller 14b Spring 15 Paper feed section 16 Paper feed roller 17 Registration roller 18 Fixing section 18a Heating roller 18b Press roller 19 Paper discharge tray 20 Recording medium 21 Toner 33 Hole transport layer

Claims (8)

An organic electroluminescence device comprising: a plurality of light emitting portions each having a light emitting layer formed of an organic material between an anode and a cathode; and a partition that electrically separates the plurality of adjacent light emitting portions, An organic electroluminescence device comprising a coating layer covering the entire surface including the light emitting portion and the partition. The organic electroluminescence device according to claim 1, wherein the coating layer is formed of an insulator. The organic electroluminescence device according to claim 1, wherein the coating layer is formed of a hygroscopic material. 4. The organic electroluminescence element according to claim 1, wherein a distance from an end of the partition wall to an end of the adjacent light emitting unit is 5 μm to 10 μm. 5. 5. The electrode according to claim 1, wherein one of the anode and the cathode formed on an upper surface of the light emitting layer has an area smaller than an area of the light emitting layer. The organic electroluminescent element of description. The organic electroluminescence element according to claim 1, wherein the partition wall is formed of a material having water repellency. An exposure apparatus comprising the organic electroluminescence element according to claim 1 as a light source. An image forming apparatus using the organic electroluminescence element according to claim 1 as a light source.

Images