JP2010231908A - Organic electroluminescence equipment, electronic equipment - Google Patents

Abstract

An organic electroluminescence device capable of suppressing light loss and improving reliability is provided.
A light emitting layer 12 is sandwiched between an element substrate 20A, an anode 10 provided on the element substrate 20A, and a cathode 11 opposite to the anode 10, and a plurality of light emitting elements disposed on the element substrate 20A. The cathode 21 includes an element 21 and a gas barrier layer 19 provided so as to cover the plurality of light emitting elements 21, and the cathode 11 includes an alkali metal, an alkaline earth metal, or silver, and is a first cathode provided on the light emitting layer 12 side. The second cathode layer 11B made of metal nitride is provided between the layer 11A, the gas barrier layer 19 and the first cathode layer 11A, in contact with the first cathode layer 11A and covering the entire surface of the first cathode layer 11A. It is characterized by having.
[Selection] Figure 1

Description

  The present invention relates to an organic electroluminescence device and an electronic device.

  With the diversification of information equipment, the need for flat display devices that consume less power and are lighter is increasing. As one of such flat display devices, an organic electroluminescence device (hereinafter referred to as “organic EL device”) having an organic light emitting layer is known.

  An organic EL device includes a light emitting element formed of a material containing an organic material. This light-emitting element has a basic structure in which an organic light-emitting layer (light-emitting layer) is sandwiched between an anode and a cathode. Furthermore, in addition to these basic configurations, the light-emitting element includes a hole injection layer disposed between the anode and the light-emitting layer in order to perform hole injection from the anode more easily, and electron injection from the cathode. Functional layers responsible for various functions, such as an electron injection layer disposed between the cathode and the light-emitting layer, have been added to make it easier, and the effects of these functional layers achieve high brightness and high luminous efficiency. There are a lot of configurations.

  Many of the materials used for forming these layers, such as the light emitting layer, the hole injection layer, and the electron injection layer, easily react with moisture and oxygen in the atmosphere and deteriorate. When these layers deteriorate, a non-light emitting region called a “dark spot” is formed in the organic EL device, and the performance as a light emitting element deteriorates. Therefore, in an organic EL device, a structure in which a light emitting element is sealed with a sealing layer such as a thin film or an insulating layer excellent in moisture resistance is proposed in order to prevent intrusion of moisture, oxygen, and the like (for example, from Patent Document 1) 3).

JP-A-7-169567 JP 2000-348859 A JP 2007-157606 A

  By the way, the light emission method of the organic EL device is opposite to the so-called bottom emission method in which the organic EL element is taken out from the substrate side through the substrate and the light emitted from the organic EL element is opposite to the substrate side on which the element is formed. There are two types of light emission methods, the so-called top emission method, which is taken out from the side. Comparing the two types of light emission methods, the top emission type organic EL device has a structure advantageous for high definition and high image quality of the display screen because it easily increases the pixel aperture ratio.

  However, in the top emission type organic EL device, there are the following problems to realize good light emission, and improvement is required.

  First, the cathode of the top emission type organic EL element needs to have a property of injecting electrons (electron injection property) in order to promote light emission in the organic light emitting layer. Examples of the material having such physical properties include a metal material having a low work function, and is preferably used as a material for forming a cathode. However, a metal material having a low work function easily reacts with moisture, oxygen, etc., easily deteriorates, and easily forms a dark spot. Therefore, the reliability of the apparatus is likely to be lowered.

  Further, in the top emission type organic EL element, the light emitted from the organic light emitting layer is extracted to the outside through the cathode. Therefore, the cathode has light transmittance in order to realize good light extraction. There is a need. Usually, in order to ensure light transmission, a technique is used in which the metal material forming the cathode is formed as a thin film that transmits light. However, the sheet resistance increases with a thin cathode. Therefore, the value of current flowing through the organic EL element included in the organic EL device changes depending on the arrangement location of the element, and display unevenness such as light emission unevenness and luminance unevenness is likely to occur on the display screen. Attempts have been made to lower the resistance by providing auxiliary wiring, but providing the auxiliary wiring between the organic EL elements tends to cause a decrease in the aperture ratio, which tends to impair the features of the top emission method.

  In addition, by using the above-described sealing structure, it is expected to prevent damage to the cathode of the thin film. However, oxygen used in the form of oxygen plasma in the sealing layer forming process and the sealing layer itself The metal material of the cathode may be oxidized by impurities such as oxygen ions and hydroxide ions.

  The present invention has been made in view of such circumstances. On the premise of a top emission type organic EL device, the present invention proposes a stable cathode structure having a low electric resistance and preventing oxidation. By providing it, an object is to provide an organic EL device that is capable of good display with little deterioration in display performance due to deterioration of the cathode. It is another object to provide an electronic device including such an organic EL device.

  In order to solve the above-mentioned problems, an organic electroluminescence device of the present invention includes an organic light emitting layer sandwiched between a substrate, an anode provided on the substrate, and a cathode facing the anode, A plurality of light emitting elements arranged; and a sealing layer provided to cover the entire surface of the plurality of light emitting elements, wherein the cathode includes an alkali metal, an alkaline earth metal, or silver, and the organic light emitting Between the first cathode layer provided on the layer side, the sealing layer and the first cathode layer, and electrically connected to the first cathode layer, covering the entire surface of the first cathode layer And a second cathode layer made of conductive metal nitride.

  First, since the second cathode layer, which is a metal nitride that is stable against oxygen and moisture, is provided so as to cover the first cathode layer that is easily oxidatively deteriorated but has good electron injection properties, the second cathode layer is provided. Can protect the first cathode layer. In addition, since the metal nitride constituting the second cathode layer has conductivity, the first cathode layer and the second cathode layer cooperate to function as a cathode, thereby reducing the resistance of the entire cathode. it can. Therefore, the electron injectability due to the first cathode layer, the oxidation prevention of the first cathode layer due to the second cathode layer, and the low resistance by stacking the first cathode layer and the second cathode layer are simultaneously realized. The cathode structure can be obtained.

  In addition, since the cathode structure is as described above, even when the cathode is exposed to the formation material or the formation process of the sealing layer when forming the sealing layer for protecting the cathode and the light emitting element, it is exposed to oxygen. On the other hand, since the stable second cathode layer prevents oxidation of the first cathode layer, it is possible to prevent deterioration of the cathode due to the formation of the sealing layer.

  Therefore, according to this configuration, it is possible to obtain an organic EL device that can display well with little deterioration in display performance due to deterioration of the cathode.

In the present invention, the sealing layer has a first inorganic protective layer that is in contact with the second cathode layer and covers the entire surface of the second cathode layer and is made of an inorganic compound having an oxygen atom. It is desirable that
According to this configuration, it is possible to satisfactorily protect the cathode and prevent the intrusion of oxygen and moisture in the atmosphere. Further, in the inorganic protective layer forming step, for example, even if oxygen plasma treatment is performed as a surface treatment before film formation to activate the surface, the cathode does not oxidize. Can be protected.

In the present invention, the first inorganic protective layer is preferably made of silicon oxynitride.
According to this configuration, since the second cathode layer and the first inorganic protective layer that are in contact with each other contain nitrogen atoms, the water resistance and adhesion at the interface between the two layers are increased, and the cathode can be protected by reliable sealing. It becomes possible.

In the present invention, the sealing layer includes an organic buffer layer provided to cover the inorganic protective layer;
And a second inorganic protective layer provided to cover the organic buffer layer.
According to this configuration, the organic buffer layer that relaxes and flattens the unevenness derived from the partition walls and wirings that separate the plurality of light emitting elements for each pixel, and the organic buffer layer that has a flattened surface on the surface. By laminating the second inorganic protective layer that prevents intrusion of oxygen and moisture, the cathode can be more reliably protected by sealing, and a highly reliable organic EL device can be provided.

In the present invention, the sealing layer is in contact with the second cathode layer and covers the entire surface of the second cathode layer, and the second inorganic protection layer is provided to cover the organic buffer layer. The organic buffer layer is preferably formed of a resin material having a polar group having an oxygen atom.
When an organic buffer layer having a polar group and having high adhesion is provided in contact with the cathode, the adhesion to the cathode is high, while the organic buffer layer has a small amount of oxygen, moisture, oxygen ions or hydroxide ions. Such impurities are likely to be contained, and trace amounts of impurities are gradually diffused to induce oxidation of the adhering cathode and deteriorate the cathode. However, according to the above-described configuration, the organic buffer layer is in contact with the second cathode layer that is stable against oxygen and moisture, so that the first cathode layer can be prevented from being deteriorated. Therefore, reliability is improved by laminating an organic buffer layer capable of reliable sealing with high adhesion and a second inorganic protective layer that prevents intrusion of atmospheric oxygen and moisture on the organic buffer layer. It is possible to provide an organic EL device with high.

In the present invention, it is desirable to have a third cathode layer made of a light-transmitting conductive metal oxide provided in contact with the second cathode layer and covering the second cathode layer.
According to this configuration, by laminating the third cathode layer having a very high light transmittance, the conductor cross-sectional area of the cathode can be widened, and the resistance of the entire cathode can be lowered without reducing the light transmittance. In addition, since the second cathode layer made of metal nitride is provided between the third cathode layer and the first cathode layer that easily oxidizes, the first cathode is formed in the step of forming the third cathode layer. Does not oxidize the layer. Therefore, it is possible to provide an organic EL device that has a cathode that achieves both low resistance and high transparency and is free from display defects such as display unevenness. For example, the display area of the organic EL device can be increased, and a device capable of good display can be obtained even when a large panel is formed.

In the present invention, the conductive metal nitride is preferably selected from the group consisting of titanium nitride, indium nitride, tin nitride, and zinc nitride.
According to this configuration, since the second cathode layer having high conductivity can be obtained, the resistance of the cathode can be reduced and an organic EL device without display unevenness can be obtained.

In the present invention, the thickness of the first cathode layer is preferably 5 nm or more and 30 nm or less.
If the thickness is less than 5 nm, a continuous layer cannot be formed, and if the thickness is more than 30 nm, it is difficult to ensure light transmittance to withstand use. When the thickness of the first cathode layer is as described above, a highly reliable organic EL device can be provided with a cathode layer having good physical properties.

An electronic apparatus according to the present invention includes the organic EL device described above.
According to this configuration, it is possible to provide an electronic apparatus having a long-life organic EL device and excellent in reliability.

It is sectional drawing which shows typically the organic electroluminescent apparatus of 1st Embodiment of this invention. It is sectional drawing which shows typically the organic electroluminescent apparatus of 2nd Embodiment of this invention. It is sectional drawing which shows typically the organic electroluminescent apparatus of 3rd Embodiment of this invention. It is sectional drawing which shows typically the organic electroluminescent apparatus of 4th Embodiment of this invention. It is a figure which shows the electronic device in embodiment of this invention.

[First Embodiment]
Hereinafter, the organic EL device 1 according to the first embodiment of the present invention will be described with reference to FIG. In all the drawings below, the film thicknesses and dimensional ratios of the constituent elements are appropriately changed in order to make the drawings easy to see.

  FIG. 1 is a cross-sectional view schematically showing the organic EL device 1. The organic EL device in the present invention is a so-called “top emission type” organic EL device. In the top emission method, light is extracted from the opposite substrate side instead of the substrate side where the organic EL elements are arranged, so the emission area is not affected by the size of various circuits arranged on the element substrate, and a wide emission area is secured. There is an effect that can be done. Therefore, luminance can be secured while suppressing voltage and current, and the lifetime of the light-emitting element can be maintained long.

As shown in the figure, the organic EL device 1 includes an element substrate (substrate) 20A on which a plurality of light emitting elements 21 are arranged, and a gas barrier layer (sealing layer) formed by laminating and covering the plurality of light emitting elements 21. 19 and a sealing substrate 31 disposed opposite to the surface of the element substrate 20A on which the plurality of light emitting elements 21 are disposed. The element substrate 20A and the sealing substrate 31 include a sealing layer 33 and The adhesive layers 34 are bonded together.
Hereinafter, each component will be described in order.

(Element board)
The element substrate 20 </ b> A includes a substrate body 20 and an element layer 14 including various wirings and TFT elements formed on the substrate body 20.

  As the substrate body 20, either a transparent substrate or an opaque substrate can be used. Examples of opaque substrates include ceramics such as alumina, metal sheets such as stainless steel that have been subjected to insulation treatment such as surface oxidation, thermosetting resins and thermoplastic resins, and films thereof (plastic films). It is done. As the transparent substrate, for example, an inorganic substance such as glass, quartz glass, or silicon nitride, or an organic polymer (resin) such as an acrylic resin or a polycarbonate resin can be used. In addition, a composite material formed by laminating or mixing the above materials can be used as long as it has optical transparency. In the present embodiment, glass is used as the material of the substrate body 20.

  On the substrate body 20, driving TFTs 123 and various wirings (not shown) are formed, and an element layer 14 in which these configurations are covered with an inorganic insulating film is formed. The inorganic insulating film that covers the element layer 14 is made of, for example, silicon oxynitride.

  On the element substrate 20A, the planarization layer 16 for relaxing the surface unevenness derived from the wirings, TFT elements and the like provided in the element substrate 20A, and the light emitted from the light emitting element 21 disposed on the planarization layer 16 And a metal reflective layer 15 that reflects the light to the sealing substrate 31 side. The planarizing layer 16 is formed of an insulating resin material, and photolithography is used as a forming method. Therefore, for example, a photosensitive acrylic resin or a cyclic olefin resin is used as the material.

  The metal reflection layer 15 is provided to serve both as a wiring and a manufacturing process, and is formed of the same metal as the wiring material, such as aluminum, titanium, molybdenum, silver, copper, or an alloy material that combines them. Therefore, it has the property of reflecting light. In this embodiment, it is made of aluminum. The metal reflection layer 15 is disposed so as to overlap the light emitting element 21 in a plane between a light emitting element 21 described later and the substrate body 20.

  A light emitting element 21 is disposed on the planarizing layer 16 in a region overlapping the metal reflective layer 15 in a plane, and between the adjacent light emitting elements 21 and between the light emitting element 21 and the end of the substrate body 20. A partition wall 13 is formed between them. In other words, the light emitting element 21 is partitioned by the partition wall 13. The partition wall 13 is formed of an insulating resin material similarly to the planarization layer 16, and a photolithography method is used for the formation method. For example, a photosensitive acrylic resin or a cyclic olefin resin is used as the material.

(Light emitting element)
The light emitting element 21 is configured by sandwiching a light emitting layer (organic light emitting layer) 12 between an anode 10 and a cathode 11, and is provided on a planarizing layer 16 surrounded by a partition wall 13. The thickness of the light emitting element 21 is about 500 nm, and has a thickness (height) difference of 1 μm or more from the partition wall 13.

  The anode 10 is formed on the planarizing layer 16 and connected to the driving TFT provided in the element substrate 20A. The anode 10 is preferably made of a material having a work function of 5 eV or more and a high hole injection effect. Examples of such a material having a high hole injection effect include metal oxides such as ITO (Indium Tin Oxide). In this embodiment, ITO is used. Note that the anode 10 does not necessarily have light transmittance, and may be a metal electrode such as aluminum that does not transmit light. In that case, since the anode 10 reflects light and has the function of the metal reflection layer 15 described above, the metal reflection layer 15 may not be provided.

  The light emitting layer 12 employs a white light emitting layer that emits white light. In this embodiment, the white light emitting layer is formed using a low molecular weight light emitting material by a vacuum deposition method. As a white light emitting material, white light is emitted by simultaneously emitting a layer (blue) doped with an anthracene dopant in a stiltylamine luminescent layer and a layer (yellow) doped with a rubrene dopant in a stiltylamine luminescent layer. The light emitting material which implement | achieves can be mentioned.

  Although a low molecular light emitting material is used here, a light emitting layer may be formed using a polymer light emitting material. It is also possible to change the configuration of each layer to have a three-layer structure in which white light is extracted by simultaneously emitting red, green, and blue colors. The light emitting element 21 may include a red light emitting element having a red light emitting layer, a green light emitting element having a green light emitting layer, and a blue light emitting element having a blue light emitting layer as the light emitting layer 12.

  A triarylamine multimer (ATP) layer (hole injection layer), a triphenyldiamine derivative (TPD) layer (hole transport layer), the light emitting layer 12 and the cathode are provided between the anode 10 and the light emitting layer 12. It is preferable that an aluminum quinolinol (Alq3) layer (electron injection layer) and LiF (electron injection buffer layer) are respectively formed between the electrodes 11 and 11 to facilitate injection of electrons and holes from each electrode. .

  The cathode 11 covers the surfaces of the light emitting layer 12 and the partition wall 13 and extends to the top of the partition wall 13 disposed on the outermost side (side closer to the outer peripheral portion of the element substrate 20A). . Further, the cathode 11 has a light semi-transmissive and semi-reflective property, and an optical resonator structure for resonating light emitted from the light emitting layer 12 is formed between the cathode 11 and the metal reflecting layer 15.

  The cathode 11 of this embodiment has a structure in which a first cathode layer 11A provided on the light emitting layer 12 side and a second cathode layer 11B provided so as to cover the first cathode layer are laminated.

  The first cathode layer 11A is formed using a material having a large electron injection effect and a low sheet resistance, and an alkali metal, an alkaline earth metal, or silver can be used as a forming material. Only one kind of these metal materials may be used, or a plurality of kinds may be used at the same time. When a plurality of types of metal materials are used at the same time, they may be alloy layers or mixed layers that are mixed with each other while maintaining the physical properties of each metal material alone.

  The film thickness of the first cathode layer 11A is preferably 5 nm or more and 30 nm or less. This is because if the thickness is less than 5 nm, a continuous layer cannot be formed, and if it is thicker than 30 nm, it is difficult to ensure light transmittance to withstand use. The first cathode layer 11A can be formed using a sputtering method, an ion plating method, or a vacuum evaporation method.

  The second cathode layer 11B is formed using a metal nitride that is stable against oxygen and moisture and has conductivity. As the forming material, a material selected from the group consisting of titanium nitride, indium nitride, tin nitride, and zinc nitride can be suitably used. Among these, titanium nitride having excellent conductivity is preferable. The film thickness of the second cathode layer 11B is preferably 30 nm or more in order to secure the conductor cross-sectional area and reduce the resistance of the cathode 11, and 200 nm or less in order to ensure the necessary light transmittance. preferable.

  The second cathode layer 11B can be formed using a sputtering method, an ion plating method, or a vacuum evaporation method. Especially when using high density plasma deposition methods such as ECR (Electron Cyclotron Resonance) plasma sputtering and ion plating (pressure gradient plasma gun deposition), the quality of the deposition environment is kept below 100 degrees. It is preferable because a high-nitride film can be formed and the film stress can be suppressed to easily increase the thickness.

  Further, a cathode wiring 22A is formed on the element substrate 20A in a region where the planarizing layer 16 in the vicinity of the outer periphery of the element substrate 20A is not formed, and the cathode wiring 22A and the cathode 11 are connected by the auxiliary wiring 24. Is conducting. Further, the cathode 11 may be in direct contact with the cathode wiring 22A without providing the auxiliary wiring 24.

  The cathode wiring 22A is formed for the purpose of energizing the cathode 11 to a power source (not shown), and is mainly provided near the outer peripheral portion of the element substrate 20A. As a material for forming the cathode wiring 22A, an aluminum-silicon alloy, a metal such as titanium, tungsten, molybdenum, or tantalum is used, and a material formed by laminating these materials in a single layer or multiple layers is used.

(Sealing layer)
A gas barrier layer 19 is formed on the element substrate 20A so as to be in contact with the element layer 14 and cover the entire surface including the end of the cathode 11. The gas barrier layer 19 is for preventing oxygen and moisture from entering, and thereby, deterioration of the light emitting element 21 due to oxygen and moisture can be suppressed. The gas barrier layer 19 of the present embodiment corresponds to the “first inorganic protective layer” in the present invention.

  The gas barrier layer 19 is provided with an inorganic compound having an oxygen atom as a forming material, and is formed using, for example, silicon oxide or silicon oxynitride. When forming these, even if oxygen plasma is used, for example, the second cathode layer 11B that is stable against oxygen is formed on the surface of the cathode 11. Can be protected.

Of these, silicon oxynitride (SiO _x N _y ), which is a silicon compound containing nitrogen, is preferable in consideration of physical properties such as transparency, gas barrier properties, and low film stress. When silicon oxynitride is used, the second cathode layer 11B and the gas barrier layer 19 that are in contact with each other contain nitrogen atoms, so that the water resistance and adhesion at the interface between the two layers are increased, and the cathode 11 is reliably sealed. Can be protected.

The contents of oxygen and nitrogen can be controlled according to the required gas barrier properties. When the content rate (nitridation rate) of nitrogen atoms is increased, the number of covalent bonds between atoms is increased (the density of covalent bonds is increased), so that dense bonds that block gas are formed, and gas barrier properties can be improved. For example, when a JIS-K7129B method is used to evaluate a laminated film of a SiON film and a PET film (PET film / SiON with a film thickness of 100 nm) whose nitriding rate is increased to a Young's modulus of about 150 to 300 GPa, The transmittance is 0.05 g / m ² · day or less, indicating a very high gas barrier performance.

  The gas barrier layer 19 is formed by using a high-density plasma deposition method such as ECR plasma sputtering, ion plating, ICP (inductively coupled plasma) -CVD, or SWP (surface wave plasma) -CVD. Formed on layer 11B. When these methods are used, the cathode 11 is exposed to oxygen plasma in the process of forming the gas barrier layer 19, but the second cathode layer 11B made of metal nitride prevents oxygen atoms from being oxidized in order to prevent oxidation of the first cathode layer 11A. A gas barrier layer 19 containing the same can be formed. In addition, as a surface treatment before formation, oxygen plasma treatment can be performed to activate the surface, and the adhesion of the gas barrier layer can be further enhanced.

  The film thickness of the gas barrier layer 19 is preferably 100 nm or more and 800 nm or less. When the gas barrier layer 19 is less than 100 nm, the film thickness is thin, so that it is easily damaged. When the gas barrier layer 19 is greater than 800 nm, for example, 1000 nm or more, cracks are likely to occur due to a decrease in film stress and flexibility, such being undesirable. In consideration of productivity in addition to sealing performance, a film thickness of 200 nm to 500 nm is more preferable.

  In the drawing, the gas barrier layer 19 is shown to be smaller (narrower) than the element substrate 20A, but the gas barrier layer 19 may extend to the end of the element substrate 20A. In order to improve efficiency, when a plurality of substrates are formed on one large substrate and then separated in a manufacturing process, so-called multi-chamfering is performed, the gas barrier layer 19 is bonded after the sealing substrate 31 is bonded. Each panel may be cut.

(Sealing substrate)
Opposite to the element substrate 20A, a sealing substrate 31 and a color filter layer 32 formed on the sealing substrate 31 are provided.

  The sealing substrate 31 is a substrate having a light transmission property for transmitting light emitted from the light emitting element 21 and a strength for protecting the thin film sealing layer. For example, an inorganic material such as glass, quartz glass, or silicon nitride, It can be formed using an organic polymer (resin) having light transmissivity, such as polyethylene terephthalate resin, acrylic resin, polycarbonate resin, and polyolefin resin. In addition, a composite material formed by laminating or mixing the above materials can be used as long as it has optical transparency. Among them, a glass substrate is particularly preferably used because of its high transparency and low moisture permeability. Further, a layer that blocks or absorbs ultraviolet rays, a functional layer such as a light reflection preventing film or a heat dissipation layer may be formed.

  A color filter layer 32 is formed on the sealing substrate 31. In the color filter layer 32, a colored layer 32a that modulates transmitted light into any one of red (R), green (G), and blue (B) is arranged in a matrix. The colored layer 32a is formed by mixing a pigment or dye showing red, green, and blue in a resin layer such as an acrylic resin. Moreover, it is good also as providing colored layers 32a, such as light blue, light cyan, and white, as needed.

  Each of the colored layers 32a is disposed to face the light emitting element 21 that emits white light. As a result, the light emitted from the light emitting element 21 passes through each of the colored layers 32a and is emitted to the viewer side as red light, green light, and blue light to perform full color display.

  A black matrix layer 32b that prevents light leakage and improves visibility is formed between the adjacent colored layers 32a and around the colored layer 32a. The black matrix layer 32b is formed of a resin colored in black.

  The color filter layer 32 is adjusted to a thickness suitable for each color in the range where the colored layer 32a is 0.5 μm or more and 2 μm or less. The black matrix layer 32b has a thickness of about 1 μm.

(Adhesive layer / seal layer)
The adhesive layer 34 fixes the sealing substrate 31 disposed opposite to the element substrate 20A, keeps the distance from the color filter layer constant, and has a buffer function against mechanical shock from the outside. A function of protecting the sealing layer is provided.

  The material for forming the adhesive layer 34 is preferably an organic material (transparent adhesive) that has translucency and has an adhesive function, and further has excellent fluidity and does not have a volatile component such as a solvent. As such a forming material, a resin adhesive such as acrylic, epoxy, or urethane can be used, but an epoxy adhesive is preferable in consideration of heat resistance and water resistance.

  Preferably, an epoxy monomer / oligomer having an epoxy group and having a molecular weight of 3000 or less is used. Here, monomers having a molecular weight of less than 1000 are monomers, and those having a molecular weight of 1000 to 3000 are oligomers. Examples of such a forming material include bisphenol A type epoxy oligomer, bisphenol F type epoxy oligomer, phenol novolac type epoxy oligomer, 3,4-epoxycyclohexenylmethyl-3 ′, 4′-epoxycyclohexene carboxylate, ε- There are caprolactone-modified 3,4-epoxycyclohexylmethyl 3 ′, 4′-epoxycyclohexanecarbochelate, and these are used alone or in combination.

  Further, the forming material of the adhesive layer 34 includes a curing agent that reacts with the epoxy monomer / oligomer as an additive. As this curing agent, those which form a cured film having excellent electrical insulation, toughness and excellent heat resistance are preferably used, and an addition polymerization type having excellent transparency and little variation in curing is preferable. For example, 3-methyl-1,2,3,6-tetrahydrophthalic anhydride, methyl-3,6-endomethylene-1,2,3,6-tetrahydrophthalic anhydride, 1,2,4,5-benzene An acid anhydride curing agent such as tetracarboxylic dianhydride, 3,3 ′, 4,4′-benzophenone tetracarboxylic dianhydride, or a polymer thereof is preferable. Moreover, you may use amine hardening | curing agents, such as an aromatic amine and an aliphatic amine. The material for forming the adhesive layer 34 to which these curing agents are added behaves as a thermosetting resin. As another additive, a silane coupling agent that improves adhesion to the gas barrier layer 19 may be included.

  Further, normally, the material for forming the adhesive layer 34 includes spherical particles (spacers) having a predetermined particle diameter for controlling the distance between the substrates, and scaly or massive inorganic materials (for adjusting the viscosity). Fillers such as inorganic fillers are often mixed. However, since these fillers may damage the gas barrier layer 19 at the time of bonding and pressure bonding, in this embodiment, a seal layer forming material in which these fillers are not mixed is used.

  The material for forming the adhesive layer 34 preferably has a viscosity of 100 to 1000 mPa · s (room temperature) when applied. The reason is that the material filling property into the space after the bonding is taken into consideration, and a material in which the curing starts after the viscosity once decreases immediately after heating is preferable. Moreover, it is preferable that the water content is a material adjusted to 1000 ppm or less.

  The adhesive layer 34 is formed by applying the above-described forming material using a coating method such as a roll coating method, a screen printing method, or a dispensing method. After the material for forming the adhesive layer 34 is applied to either the element substrate 20A or the sealing substrate 31, both are aligned, and after pressure bonding in a reduced pressure atmosphere, heating is performed in the range of 80 to 120 ° C. By doing so, both are fixed through the adhesive layer 34.

  When a photoreactive initiator is added, when a forming material having a high curing rate is used, ultraviolet irradiation is performed after bonding. On the other hand, when using a forming material having a slow curing rate, it is preferable to start the curing reaction by irradiating with ultraviolet rays before bonding.

  Further, around the adhesive layer 34, to secure the alignment position when the element substrate 20A and the sealing substrate 31 are bonded together, to prevent the adhesive layer 34 from sticking out, and to prevent moisture from entering the apparatus. Further, a sealing layer 33 made of a material different from that of the adhesive layer 34 may be provided. When the sealing layer 33 is provided, the sealing layer 33 is preferably provided so as to overlap the peripheral edge of the organic buffer layer 18 in order to prevent damage such as cracking or peeling of the gas barrier layer 19.

  The forming material of the sealing layer 33 is made of a resin material that is cured by ultraviolet rays and has an improved viscosity. For example, an epoxy monomer / oligomer having a molecular weight of 3000 or less shown as a material for forming the adhesive layer can be mentioned, and these can be used alone or in combination.

  Further, the forming material of the seal layer 33 includes a curing agent that reacts with the epoxy monomer / oligomer. Examples of the curing agent include a diazonium salt, a diphenyliodonium salt, a triphenylsulfonium salt, a sulfonate ester, an iron arene complex, a silanol / aluminum complex, and the like. Are preferably used. The material for forming the seal layer 33 to which these curing agents are added behaves as a light (ultraviolet) curable resin.

  The viscosity at the time of applying the forming material of the seal layer 33 is preferably 10 Pa · s or more and 200 Pa · s or less (room temperature). In addition, when an additive called a cation hold agent is used so that the viscosity gradually increases after ultraviolet irradiation, the light irradiation step after bonding can be eliminated, and the forming material of the seal layer 33 hardly flows. Therefore, the bonding process is facilitated. Further, even a narrow seal width of 1 mm or less is preferable because the seal layer 33 can be prevented from being ruptured and the filler after sticking can be prevented from sticking out. Moreover, it is preferable that the water content is a material adjusted to 1000 ppm or less.

As the material for forming the seal layer 33, a material in which a filler such as a spacer or an inorganic filler is not mixed is used for the same reason as the material for forming the adhesive layer.
The organic EL device 1 of the present embodiment has the above configuration.

  According to the organic EL device 1 having the above-described configuration, the cathode 11 that simultaneously achieves good electron injectability, stability to moisture and oxygen, and low sheet resistance can be obtained. An organic EL device capable of good display with little deterioration in performance can be obtained.

[Second Embodiment]
FIG. 2 is an explanatory diagram of an organic EL device according to the second embodiment of the present invention. The organic EL device of the present embodiment is partly in common with the organic EL device 1 of the first embodiment, and the sealing structure for sealing the cathode 11 is different. Therefore, in this embodiment, the same code | symbol is attached | subjected about the component which is common in 1st Embodiment, and detailed description is abbreviate | omitted.

  As shown in the figure, the organic EL device 2 of the present embodiment has an organic buffer layer 18 between the cathode 11 and the gas barrier layer 19. The gas barrier layer 19 of this embodiment corresponds to the “second inorganic protective layer” in the present invention.

  The organic buffer layer 18 is arranged so as to fill the unevenness of the surface of the cathode 11 formed in an uneven shape due to the influence of the shape of the partition wall 13 and relax the undulation. The organic buffer layer 18 has a function of relaxing stress generated by warpage and volume expansion of the element substrate 20A and preventing the cathode 11 and the light emitting layer 12 from peeling from the partition wall 13. Moreover, since the undulations on the upper surface of the organic buffer layer 18 are alleviated, there is no portion where stress is concentrated on the gas barrier layer 19 described later, and the generation of cracks can be prevented. The Young's modulus of the organic buffer layer 18 is preferably in the range of 0.1 GPa to 5 GPa.

  The organic buffer layer 18 is preferably formed of an organic compound material that is excellent in fluidity and has no solvent or volatile component, and is a raw material for the polymer skeleton, and has an epoxy group as such a forming material. Epoxy monomers / oligomers having a molecular weight of 3000 or less can be suitably used. For example, bisphenol A type epoxy oligomer, bisphenol F type epoxy oligomer, phenol novolac type epoxy oligomer, polyethylene glycol diglycidyl ether, alkyl glycidyl ether, 3,4-epoxycyclohexenylmethyl-3 ′, 4′-epoxycyclohexene carboxylate, There are ε-caprolactone-modified 3,4-epoxycyclohexylmethyl 3 ′, 4′-epoxycyclohexanecarbochelate, and these may be used alone or in combination.

  Further, the forming material of the organic buffer layer 18 includes a curing agent that reacts with the epoxy monomer / oligomer. As such a curing agent, an agent that forms a cured film having excellent electrical insulation and adhesiveness, high hardness, toughness and excellent heat resistance is suitably used, and it has excellent transparency and little variation in curing. The polymerization type is preferred. For example, 3-methyl-1,2,3,6-tetrahydrophthalic anhydride, methyl-3,6-endomethylene-1,2,3,6-tetrahydrophthalic anhydride, 1,2,4,5-benzene Acid anhydride curing agents such as tetracarboxylic dianhydride and 3,3 ′, 4,4′-benzophenonetetracarboxylic dianhydride are preferred. The material for forming the organic buffer layer 18 to which these curing agents are added behaves as an excellent thermosetting resin.

  When these acid anhydride type curing agents react with water molecules to produce carboxylic acid, they do not react with the above-mentioned epoxy monomer / oligomer, so that the material for forming the organic buffer layer 18 is adjusted to a moisture content of 10 ppm or less. It is desirable that

  Furthermore, low-temperature curing is facilitated by adding trace amounts of amine compounds such as alcohols and aminophenols that have a high molecular weight and are difficult to volatilize such as 1,6-hexanediol as reaction accelerators that promote the reaction (ring opening) of acid anhydrides. Become. These curing is performed by heating in the range of 60 to 100 ° C., and the cured film becomes a polymer having an ester bond.

  The viscosity of the organic buffer layer forming material is preferably 2000 mPa · s (room temperature: 25 ° C.) or more. This is because it does not penetrate into the light emitting layer 12 immediately after the application and does not generate a non-light emitting region called a dark spot. Moreover, as a viscosity of the buffer layer forming material which mixed these raw materials, 4000 mPa * s or more and 10000 mPa * s or less (room temperature) are preferable. By adjusting the viscosity within this range, the generation of bubbles can be suppressed.

  The organic buffer layer 18 is formed by applying the above-described forming material using a vacuum screen printing method under a reduced pressure atmosphere. By applying in a reduced-pressure atmosphere, mixing of moisture into the organic buffer layer 18 is suppressed, and bubbles generated during application are removed.

  Further, the optimum film thickness of the organic buffer layer 18 is preferably 3 μm or more and 5 μm or less. When the organic buffer layer 18 is thicker, it is easier to prevent the gas barrier layer 19 from being damaged when foreign matter is mixed in. However, when the combined thickness of the organic buffer layer 18 exceeds 5 μm, the distance between the colored layer 32a and the light emitting layer 12 This is because the light that escapes to the side of the apparatus increases and the efficiency of extracting the light decreases.

  When the organic buffer layer 18 having a polar group and having high adhesion is provided in contact with the cathode 11 as described above, the adhesion to the cathode 11 is high, while the organic buffer layer 18 has a trace amount of oxygen, moisture, or There is a possibility that impurities such as oxygen ions and hydroxide ions are likely to be contained, and a slight amount of impurities are gradually diffused to induce oxidation of the cathode 11 that is in close contact, thereby deteriorating the cathode 11. However, since the organic buffer layer 18 of the present embodiment is provided in contact with the second cathode layer 11B that is stable against oxygen and moisture, the first cathode layer 11A due to a small amount of impurities contained in the organic buffer layer 18 is provided. Can be prevented.

  Therefore, according to the organic EL device 2 having the above-described configuration, the organic buffer layer 18 that can be surely sealed with high adhesion, and the entry of oxygen and moisture in the atmosphere onto the organic buffer layer are prevented. By stacking the gas barrier layer 19, it is possible to obtain a highly reliable organic EL device 2.

[Third Embodiment]
FIG. 3 is an explanatory diagram of an organic EL device according to the third embodiment of the present invention. The organic EL device of the present embodiment is partly in common with the organic EL device 2 of the second embodiment, and the laminated structure of the cathode 11 is different. Therefore, in this embodiment, the same code | symbol is attached | subjected about the component which is common in 2nd Embodiment, and detailed description is abbreviate | omitted.

  As shown in the figure, the cathode 11 of the organic EL device 3 of the present embodiment has a third cathode layer 11C provided so as to cover the second cathode layer 11B. The third cathode layer 11C has a function of assisting conduction of the entire cathode 11, and does not hinder light extraction from the cathode. Therefore, the third cathode layer 11C is formed using a light-transmitting conductive metal oxide.

  The third cathode layer 11C is made of, for example, ITO, ZnO (zinc oxide), IZO (indium zinc oxide, Izzet Oh (registered trademark)), AZO (aluminum zinc oxide), GZO (gallium zinc oxide), or the like. It is formed. The film thickness of the third cathode layer 11C can be arbitrarily set according to the required conductivity.

  Such third cathode layer 11C can be formed by using a high-density plasma film forming method. During the formation, the second cathode layer 11B is exposed to oxygen plasma, but the second cathode layer 11B made of metal nitride is stable against oxygen, and the second cathode layer 11B is the first cathode layer 11A. Therefore, the third cathode layer 11C can be formed satisfactorily.

  According to the organic EL device 3 having the above-described configuration, it is possible to provide the organic EL device 3 having the cathode 11 that achieves both low resistance and ensuring transparency and is free from display defects such as display unevenness. . For example, the display area of the organic EL device can be increased, and a device capable of good display can be obtained even when a large panel is formed.

[Fourth Embodiment]
FIG. 4 is an explanatory diagram of an organic EL device according to the fourth embodiment of the present invention. The organic EL device of the present embodiment is partly in common with the organic EL device 2 of the second embodiment, and the sealing structure for sealing the cathode 11 is different. Therefore, in this embodiment, the same code | symbol is attached | subjected about the component which is common in 2nd Embodiment, and detailed description is abbreviate | omitted.

  As shown in the figure, the organic EL device 4 of this embodiment has an electrode protective layer 17 between the cathode 11 and the organic buffer layer 18. The electrode protective layer 17 is provided in order to prevent the adhesive layer 34 before curing from penetrating into the light emitting layer 12 through a pinhole or the like, assuming that the cathode 11 has a pinhole or a crack. The electrode protective layer 17 of this embodiment corresponds to the “first inorganic protective layer” in the present invention, and the gas barrier layer 19 corresponds to the “second inorganic protective layer” in the present invention.

  The electrode protective layer 17 may be composed of a silicon compound such as silicon oxynitride or silicon nitride similar to the gas barrier layer 19 described above in consideration of transparency, adhesion, water resistance, insulation, and gas barrier properties. desirable. In the present embodiment, silicon oxynitride is used as a material for forming the electrode protection layer 17, and the electrode barrier layer 19 is formed using the same formation method as that for the gas barrier layer 19. Moreover, it is preferable to set the film thickness of the electrode protective layer 17 to 100 nm or more and 400 nm or less in order to provide the necessary gas barrier property and to provide flexibility to prevent cracks.

  According to the organic EL device 4 configured as described above, the electrode protective layer 17, the organic buffer layer 18, and the gas barrier layer 19 cooperate to seal from the external environment and protect the cathode 11, so that the organic EL device 4 has high reliability. The EL device 4 can be provided.

[Electronics]
Next, an example of an electronic device including the organic EL device described in the above embodiment will be described. FIG. 5A is a perspective view showing an example of a mobile phone. In FIG. 5A, the mobile phone 50 includes a display unit 51. The display unit 51 includes the organic EL device according to the present invention.

  FIG. 5B is a perspective view showing an example of a portable information processing apparatus such as a word processor or a personal computer. 5B, the information processing device 60 includes an input unit 61 such as a keyboard, a display unit 62, and a housing 63. The display unit 62 includes the organic EL device according to the present invention.

  FIG. 5C is a perspective view showing an example of a wristwatch type electronic device. In FIG. 5C, the timepiece 70 includes a display unit 71. The display unit 71 includes the organic EL device according to the present invention.

  Each of the electronic devices shown in FIGS. 5A to 5C is provided with the organic EL device shown in the above-described embodiment, so that an electronic device capable of high-quality display and excellent in reliability. It can be a device.

  The electronic device is not limited to the electronic device, and can be applied to various electronic devices. For example, a desktop computer, a liquid crystal projector, a multimedia personal computer (PC) and an engineering workstation (EWS), a pager, a word processor, a television, a viewfinder type or a monitor direct view type video tape recorder, an electronic notebook, an electronic The present invention can be applied to electronic devices such as a desktop computer, a car navigation device, a POS terminal, and a device having a touch panel.

  The preferred embodiments of the present invention have been described above with reference to the accompanying drawings, but it goes without saying that the present invention is not limited to such examples. Various shapes, combinations, and the like of the constituent members shown in the above-described examples are examples, and various modifications can be made based on design requirements and the like without departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 1-4 ... Organic EL apparatus (organic electroluminescent apparatus) 10 ... Anode, 11 ... Cathode, 11A ... 1st cathode layer, 11B ... 2nd cathode layer, 11C ... 3rd cathode layer, 12 ... Light emitting layer (organic light emission) Layer), 17 ... electrode protective layer (first inorganic protective layer, sealing layer), 18 ... organic buffer layer (sealing layer), 19 ... gas barrier layer (first inorganic protective layer, second inorganic protective layer, sealing) Layer), 20A ... element substrate (substrate), 21 ... light emitting element, 50 ... mobile phone (electronic device), 60 ... information processing device (electronic device), 70 ... watch (electronic device),

Claims (9)

A substrate,
A plurality of light emitting elements disposed on the substrate, sandwiching an organic light emitting layer between an anode provided on the substrate and a cathode facing the anode;
A sealing layer provided to cover the entire surface of the plurality of light emitting elements,
The cathode includes an alkali metal, an alkaline earth metal, or silver, and a first cathode layer provided on the organic light emitting layer side;
A second cathode made of a conductive metal nitride electrically connected to the first cathode layer and covering the entire surface of the first cathode layer between the sealing layer and the first cathode layer And an organic electroluminescent device.   The sealing layer has a first inorganic protective layer that is in contact with the second cathode layer, covers the entire surface of the second cathode layer, and includes an inorganic compound having an oxygen atom as a forming material. The organic electroluminescent device according to claim 1, wherein   The organic electroluminescence device according to claim 2, wherein the first inorganic protective layer is made of silicon oxynitride. The sealing layer is an organic buffer layer provided to cover the inorganic protective layer;
The organic electroluminescence device according to claim 2, further comprising: a second inorganic protective layer provided so as to cover the organic buffer layer. The sealing layer is in contact with the second cathode layer and covers the entire surface of the second cathode layer; and an organic buffer layer,
A second inorganic protective layer provided to cover the organic buffer layer,
2. The organic electroluminescence device according to claim 1, wherein the organic buffer layer is formed of a resin material having a polar group having an oxygen atom.   6. The method according to claim 1, further comprising a third cathode layer made of a light-transmitting conductive metal oxide provided in contact with the second cathode layer and covering the second cathode layer. 2. The organic electroluminescence device according to item 1.   7. The organic electroluminescence according to claim 1, wherein the conductive metal nitride is selected from the group consisting of titanium nitride, indium nitride, tin nitride, and zinc nitride. apparatus.   8. The organic electroluminescence device according to claim 1, wherein a thickness of the first cathode layer is 5 nm or more and 30 nm or less.   An electronic apparatus comprising the organic electroluminescence device according to claim 1.

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