JP5573545B2 - Manufacturing method of organic EL display device - Google Patents

Description

  The present invention relates to a method for manufacturing an organic EL display device.

  The organic EL display device generally has an organic EL display panel in which a plurality of organic EL elements are formed on a substrate. The organic EL element of this organic EL display panel is one in which an organic light emitting layer made of an organic light emitting material is formed between two opposing electrodes, and light is emitted by passing a current through the organic light emitting layer. In addition, the thickness of the organic light emitting layer is important for producing a reliable element. In addition, in order to make a color display using this, it is necessary to pattern with high definition.

In general, a display substrate in which patterned photosensitive polyimide is formed in a partition shape so as to partition subpixels is used. At that time, the partition pattern is formed so as to cover the edge portion of the transparent electrode formed as an anode.
Next, there are two types of methods for forming a hole injection layer for injecting hole carriers: a dry film formation method and a wet film formation method. Dispersed polythiophene derivatives are used. In the case of a dry film formation method, a hole injection layer is formed by vapor deposition or sputtering using an inorganic material such as an organic material or metal oxide having hole transport capability. In the case of dry coating, it is possible to coat the entire surface relatively easily and uniformly.

Next, smooth injection of holes injected into the hole injection layer from the electrode into the light emitting layer and clogging at the interface of the light emitting layer so that electrons injected from the counter electrode to be formed later do not flow into the hole transport layer. As a role, a hole transport layer is formed between the hole injection layer and the light emitting layer. The formation method is the same as that of the hole injection layer.
Similarly, there are two methods for forming the organic light emitting layer: a dry film forming method and a wet film forming method. However, when using a vacuum evaporation method, which is a dry film forming method that facilitates uniform film formation, a fine pattern mask is used. Therefore, it is necessary to perform patterning using a large-sized substrate and fine patterning is very difficult.

  Therefore, recently, a method of forming a thin film using a wet film forming method by dissolving a polymer material in a solvent to form a coating liquid has been tried. When a light emitting medium layer including an organic light emitting layer is formed by a wet film formation method using a coating material of a polymer material, the layer structure is generally a two-layer structure in which a hole transport layer and an organic light emitting layer are laminated from the anode side. Is. At this time, the organic light emitting layer is formed by dissolving or stably dispersing organic light emitting materials having respective emission colors of red (R), green (G), and blue (B) in a solvent in order to form a color panel. It can be applied separately using organic luminescent ink (see Patent Documents 1 and 2).

  In addition to the organic light emitting layer, a carrier injection layer (also called a carrier transport layer) is formed between the electrodes. The carrier injection layer controls the injection amount of electrons when injecting electrons from the electrode to the organic light emitting layer, or controls the injection amount of holes when holes are injected from the other electrode to the organic light emitting layer. A layer used to control and refers to a layer inserted between an electrode and an organic light emitting layer. As the electron injection layer, an electron transporting organic substance such as a metal complex of a quinolinol derivative or a relatively small work function such as Ca or Ba such as an alkali metal is used, or a plurality of layers having these functions are stacked. In some cases.

  As shown in FIG. 1, the organic EL element formed on the substrate of the organic EL display panel has a pixel electrode (first electrode) 102 on the substrate 101, and holes are injected on the pixel electrode 102. The layer 104, the hole transport layer 105, the organic light emitting layer 106, and the counter electrode (second electrode) 107 are stacked. The pixel electrode 102 is divided into pixel (sub-pixel) units by a partition wall 103 formed on the substrate 101. When such an organic EL display display panel composed of a plurality of organic EL elements is lit at a predetermined luminance, the rate of decrease in luminance with respect to time is greatest immediately after the first lighting, which causes the display panel to burn. is there.

As a means for solving this problem, as an aging method, light is emitted at a predetermined luminance for a predetermined time, and the product after the initial decrease in luminance is used as a product. However, causing the initial luminance degradation is equivalent to lowering the efficiency, and there is a problem that the original device performance cannot be fully utilized because the state deteriorated to some extent is made the initial state as a product.
As a method for stabilizing the organic EL element, it has been proposed to apply a forward voltage up to a drive voltage value in a stepped waveform (see Patent Document 1). However, in this method, an electric field is applied to the light emitting region, and there is a concern about deterioration of the organic light emitting material. As another stabilization method, it has been proposed to heat the organic electroluminescent element at a temperature of 50 ° C. or higher and below the melting point of the organic compound (see Patent Document 2). However, this method does not significantly improve the luminance half-life of 18 to 25 hours.

JP-A-4-14794 JP-A-5-18264

  In the organic EL display panel, since the ratio of the luminance decrease with respect to time is large immediately after lighting, and the display panel is burned, it is necessary to perform aging until the change in luminance with respect to time becomes small. The initial luminance degradation is considered to be mainly due to the instability of each interface in the layer structure, but the conventional aging method uses a method that is simply deteriorated by an accelerated lighting test. The light emitting material itself was also deteriorated. Therefore, an object of the present invention is to provide a method for manufacturing an organic EL display device using an aging method that can suppress deterioration of a light emitting material while accelerating stabilization of an interface.

In order to solve the above problems, an invention according to claim 1 of the present invention includes a substrate, a plurality of pixel electrodes formed on the substrate, a counter electrode facing each of the pixel electrodes, and the counter A method for manufacturing an organic EL display device comprising an organic EL display display panel comprising a light emitting medium layer having an organic light emitting layer made of an organic light emitting material between an electrode and the pixel electrode, the organic EL display display panel After forming the organic EL display panel, the organic EL display panel is made of the organic light emitting material with a forward voltage applied to the pixel electrode and the counter electrode so that the light emission luminance of the organic light emitting layer is 1 cd / m ² or less . The organic EL display panel is aged by being left in an atmosphere lower than the glass transition temperature.

The invention according to claim 2 of the present invention is the manufacturing method of the organic EL display device according to claim 1, the aging of the organic EL display display panel to the light-emitting luminance before Symbol organic light-emitting layer decreases 10% or more It is characterized by performing .
The invention according to claim 3 of the present invention is the method of manufacturing an organic EL display device according to claim 1 or 2, wherein the aging of the organic EL display panel is performed under a light source not containing a wavelength component of 600 nm or less. It is characterized by.

The invention according to claim 4 of the present invention is the method of manufacturing an organic EL display device according to any one of claims 1 to 3, wherein at least the organic light emitting layer of the light emitting medium layer is formed by a wet film forming method or a dry film forming method. It is formed by a film method .
The invention according to claim 5 of the present invention is the method of manufacturing an organic EL display device according to any one of claims 1 to 4, wherein the aging time of the organic EL display panel is 400 hours or more. Features.

  According to the present invention, after the organic EL display panel is formed, the organic EL display panel is left in a temperature atmosphere lower than the glass transition temperature of the organic light emitting material with a voltage applied to the pixel electrode and the counter electrode. By aging the organic EL display panel, unlike the aging performed in the normal use state, only the change of the layer interface, which is the main factor of the initial luminance degradation, is accelerated to accelerate the organic EL display display panel. Aging can be performed. Then, by aging the organic EL display panel in an atmosphere at a temperature lower than the glass transition temperature of the organic light emitting material, either a hole or an electron is applied in the reverse voltage or low voltage region as shown in FIG. Since carriers are in excess and current flows in the organic light-emitting layer with little recombination, an electric field can be applied to the light-emitting layer without damaging the organic light-emitting material, and only the layer interface is stabilized. be able to. Therefore, early deterioration of the organic EL display panel due to aging can be suppressed.

It is sectional drawing which shows the structure of an organic electroluminescence display panel typically. It is a figure for demonstrating the effect of this invention. It is sectional drawing which shows typically the structure of the board | substrate with TFT used for an organic electroluminescence display panel. It is a figure which shows an example of the relief printing apparatus used when manufacturing an organic electroluminescence display panel.

Hereinafter, a method for manufacturing an organic EL display device according to the present invention will be described with reference to the drawings.
FIG. 1 is a diagram schematically showing the structure of an organic EL display panel. The organic EL display panel shown in FIG. 1 has a plurality of organic EL elements on a substrate 101, and each organic EL element includes a pixel electrode 102, a light emitting medium layer 108, and a counter electrode 107.
The pixel electrode 102 is formed on the substrate 101, and is divided into pixel units by a partition wall 103 formed on the substrate 101 in order to form a pixel electrode of the organic EL display panel.

The light emitting medium layer 108 is formed on the pixel electrode 102, and the counter electrode 107 is formed on the light emitting medium layer 108 so as to face the pixel electrode 102. The light emitting medium layer 108 has a carrier injection layer 104 for injecting electrons or holes. The carrier injection layer 104 is formed on the pixel electrode 102.
The light emitting medium layer 108 has a carrier transport layer 105 formed on the carrier injection layer 104 and an organic light emitting layer 106 formed on the carrier transport layer 105. Is transported from the carrier injection layer 104 to the organic light emitting layer 106.

The light emitting medium layer 108 includes an electron injection layer and a hole blocking layer (hole transport layer) between the cathode and the light emitting layer, and a hole injection layer and electron blocking layer (hole transport layer) between the anode and the light emitting layer. Layer) or the like may be formed as necessary.
By arranging such organic EL elements as pixels (subpixels), an organic EL display panel can be formed. A full-color organic EL display panel can be manufactured by coating the light emitting layer 106 constituting each pixel with, for example, three colors of R (red), G (green), and B (blue).

  Hereinafter, as an organic EL display device, an active matrix driving type organic EL display device using the pixel electrode 102 as an anode and the counter electrode 107 as a cathode will be described. In this case, the pixel electrode 102 is partitioned by the first partition 103 for each pixel, and the counter electrode 107 is an electrode separated and formed by the second partition formed on the first partition 103. In addition, the carrier injection layer 104 of the light emitting medium layer 108 is a hole transporting hole injection layer. Moreover, it is good also as an organic EL element of the reverse structure which used the pixel electrode side as the anode. In this case, the carrier injection layer 104 is an electron transporting electron injection layer.

<Board>
FIG. 3 is a cross-sectional view schematically showing the structure of a substrate with TFTs used in an organic EL display panel. A substrate (back plane) 308 shown in FIG. 3 includes a thin film transistor (TFT) and a pixel electrode (lower electrode) 102 of the organic EL display panel, and the TFT and the pixel electrode 102 are electrically connected.
The TFT and the active matrix driving organic EL display device formed above the TFT are supported by a support (substrate) 101. Any material can be used as the support 101 as long as it is a support having mechanical strength and insulating properties and excellent dimensional stability. For example, plastic films and sheets such as glass, quartz, polypropylene, polyethersulfone, polycarbonate, cycloolefin polymer, polyarylate, polyamide, polymethyl methacrylate, polyethylene terephthalate, polyethylene naphthalate, etc., or oxidation to these plastic films and sheets Metal oxide such as silicon and aluminum oxide, metal fluoride such as aluminum fluoride and magnesium fluoride, metal nitride such as silicon nitride and aluminum nitride, metal oxynitride such as silicon oxynitride, acrylic resin, epoxy resin Translucent substrates made of single layer or laminated polymer resin films such as silicone resin and polyester resin, metal foils such as aluminum and stainless steel, sheets and plates, and aluminum films on the plastic films and sheets. It can be used beam, copper, nickel, stainless steel and metal film non-translucent substrate as a laminate of such.

  What is necessary is just to select the translucency of a support body according to which surface light extraction is performed from. In order to avoid moisture intrusion into the organic EL display device, the support made of these materials has been subjected to moisture-proofing treatment or hydrophobic treatment by forming an inorganic film or applying a fluororesin. It is preferable. In particular, in order to avoid moisture intrusion into the light emitting medium layer 108, it is preferable to reduce the moisture content and gas permeability coefficient of the support.

  As the thin film transistor provided over the support 101, a known thin film transistor can be used. Specifically, a thin film transistor mainly including an active layer 311 in which a source / drain region and a channel region are formed, a gate insulating film 309, and a gate electrode 314 can be given. The structure of the thin film transistor is not particularly limited, and examples thereof include a staggered type, an inverted staggered type, a top gate type, and a coplanar type.

The active layer 311 is not particularly limited, and examples thereof include inorganic semiconductor materials such as amorphous silicon, polycrystalline silicon, microcrystalline silicon, cadmium selenide, thiophene oligomers, poly (p-ferylene vinylene), and the like. The organic semiconductor material can be used. These active layers may be formed by, for example, depositing amorphous silicon by plasma CVD, ion doping, forming amorphous silicon by LPCVD using SiH ₄ gas, and crystallizing amorphous silicon by solid phase growth. After obtaining silicon, ion doping by ion implantation, LPCVD using Si ₂ H ₆ gas, and amorphous silicon by PECVD using SiH ₄ gas, and excimer laser or other laser After annealing and crystallizing amorphous silicon to obtain polysilicon, polysilicon is laminated by ion doping (low temperature process), low pressure CVD or LPCVD, and thermally oxidized at 1000 ° C. or higher. Gate insulation film Form the gate electrode 314 of the n + polysilicon is formed thereon, then, a method of ion doping (high temperature process), and the like by an ion implantation method.

As the gate insulating film 309, a film normally used as a gate insulating film can be used. For example, the gate insulating film 309 can be obtained by thermally oxidizing SiO ₂ formed by PECVD, LPCVD, or the like, or a polysilicon film. SiO ₂ or the like can be used.
As the gate electrode 314, a material usually used as a gate electrode can be used. For example, a metal such as aluminum or copper, a refractory metal such as titanium, tantalum or tungsten, or a silicide of polysilicon or refractory metal. And polycide.

The thin film transistor may have a single gate structure, a double gate structure, or a multi-gate structure having three or more gate electrodes. Moreover, you may have a LDD structure and an offset structure. Further, two or more thin film transistors may be arranged in one pixel.
The thin film transistor needs to be connected so as to function as a switching element of the organic EL display device, and the drain electrode 310 of the thin film transistor and the pixel electrode 102 of the organic EL display panel are electrically connected. In FIG. 3, reference numeral 313 denotes a scanning line for switching scanning the TFT.

<Pixel electrode>
A pixel electrode 102 is formed on the substrate, and patterning is performed as necessary. In the present invention, the pixel electrode 102 is partitioned by the partition wall 103 and becomes a pixel electrode corresponding to each pixel. Examples of the material of the pixel electrode 102 include metal composite oxides such as ITO (indium tin composite oxide), indium zinc composite oxide, and zinc aluminum composite oxide, metal materials such as gold and platinum, these metal oxides, Either a single layer or a laminate of fine particle dispersion films in which fine particles of a metal material are dispersed in an epoxy resin or an acrylic resin can be used.

When the pixel electrode 102 is used as an anode, it is preferable to select a material having a high work function such as ITO. In the case of a so-called bottom emission structure in which light is extracted from below, it is necessary to select a light-transmitting material. If necessary, in order to reduce the wiring resistance of the pixel electrode 102, a metal material such as copper or aluminum may be provided as an auxiliary electrode.
As a formation method of the pixel electrode 102, depending on the material, dry film formation methods such as resistance heating evaporation method, electron beam evaporation method, reactive evaporation method, ion plating method, sputtering method, gravure printing method, screen printing A wet film forming method such as a method can be used.

  As a patterning method of the pixel electrode 102, an existing patterning method such as a mask vapor deposition method, a photolithography method, a wet etching method, or a dry etching method can be used depending on a material or a film forming method. In the case of using a substrate on which a TFT is formed, it is preferable that the substrate be formed so as to be conductive corresponding to the underlying pixel.

<Partition wall>
The partition wall 103 is preferably formed so as to partition a light emitting region corresponding to a pixel and cover an end portion of the pixel electrode 102. In general, in an active matrix drive type display device, a pixel electrode is formed for each pixel (sub-pixel), and each pixel tries to occupy as large an area as possible so that it covers the end of the pixel electrode. The most preferable shape of the partition wall 103 is basically a lattice shape that divides each pixel electrode by the shortest distance.

  As in the conventional method, the partition wall 103 is formed by uniformly forming an inorganic film on a substrate, masking it with a resist, and performing dry etching, or laminating a photosensitive resin on a substrate, and photolithography. The method of setting it as a predetermined pattern is mentioned. If necessary, a water repellent may be added, or liquid or water repellency may be imparted to the ink after irradiation with plasma or UV. A preferable height of the partition wall 103 is 0.1 μm to 10 μm, and more preferably about 0.5 μm to 2 μm.

<Carrier injection layer>
The carrier injection layer 104 is formed in a pattern or on the entire surface so as to cover the pixel electrode 102. Examples of the hole transport material forming the carrier injection layer 104 include polyaniline derivatives, polythiophene derivatives, polyvinylcarbazole (PVK) derivatives, poly (3,4-ethylenedioxythiophene) (PEDOT), and the like. These materials can be dissolved or dispersed in a solvent, and a carrier injection layer can be formed by using various coating methods using a spin coater or the like and a relief printing method.

When an inorganic material is used as the hole transport material, examples of the inorganic material include Cu ₂ O, Cr ₂ O ₃ , Mn ₂ O ₃ , FeOx (x to 0.1), NiO, CoO, Pr ₂ O ₃ , Ag _2. Transition metal oxides such as O, MoO ₂ , Bi ₂ O ₃ , ZnO, TiO ₂ , SnO ₂ , ThO ₂ , V ₂ O ₅ , Nb ₂ O ₅ , Ta ₂ O ₅ , MoO ₃ , WO ₃ and MnO ₂ An inorganic compound containing one or more of these nitrides and sulfides can also be used. However, the inorganic material is not limited to these. Inorganic materials are preferred because many materials are excellent in heat resistance and electrochemical stability. These can be formed as a single layer or a stacked structure of a plurality of layers, or a mixed layer. The preferred film thickness is 5 nm or more, more preferably about 15 nm or more.

<Hole transport layer>
As a method for forming the hole transport layer 105, depending on the material, a dry film formation method such as a resistance heating evaporation method, an electron beam evaporation method, a reactive evaporation method, an ion plating method, a sputtering method, a spin coating method, Although an existing film formation method such as a wet film formation method such as a sol-gel method can be used, the present invention is not limited to these, and a general film formation method can also be used.

  After forming the carrier injection layer 104 on the pixel electrode 102, the hole transport layer 105 is formed on the carrier injection layer 104. Materials used for the hole transport layer 105 include polymers containing aromatic amines such as polyvinyl carbazole or derivatives thereof, polyarylene derivatives having aromatic amines in the side chain or main chain, arylamine derivatives, and triphenyldiamine derivatives. Is mentioned. The hole transport layer 105 can be formed by dissolving or dispersing these materials in a solvent and using various coating methods using a spin coater or the like and a relief printing method.

<Organic light emitting layer>
After forming the hole transport layer 105, the organic light emitting layer 106 is formed on the hole transport layer 105. The organic light emitting layer 106 is a layer that emits light by passing an electric current. When the display light emitted from the organic light emitting layer 106 is monochromatic, the organic light emitting layer 106 is formed so as to cover the hole transport layer 105. Can be suitably used by performing patterning as necessary.

  Examples of the organic light-emitting material forming the organic light-emitting layer 106 include, for example, coumarin-based, perylene-based, pyran-based, anthrone-based, porphyrin-based, quinacridone-based, N, N′-dialkyl-substituted quinacridone-based, naphthalimide-based, N, N ′. -Diaryl substituted pyrrolopyrrole, iridium complex and other luminescent dyes dispersed in polymers such as polystyrene, polymethyl methacrylate, polyvinyl carbazole, polyarylene, polyarylene vinylene and polyfluorene Although molecular material is mentioned, this invention is not limited to these.

  These organic light emitting materials are dissolved or stably dispersed in a solvent to form an organic light emitting ink. Examples of the solvent for dissolving or dispersing the organic light-emitting material include toluene, xylene, acetone, anisole, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, or a mixed solvent thereof. Among them, aromatic organic solvents such as toluene, xylene, and anisole are preferable from the viewpoint of the solubility of the organic light emitting material. Moreover, surfactant, antioxidant, a viscosity modifier, a ultraviolet absorber, etc. may be added to organic luminescent ink as needed.

  In addition to the polymer materials described above, 9,10-diarylanthracene derivatives, pyrene, coronene, perylene, rubrene, 1,1,4,4-tetraphenylbutadiene, tris (8-quinolato) aluminum complex, tris (4-methyl) -8-quinolate) aluminum complex, bis (8-quinolate) zinc complex, tris (4-methyl-5-trifluoromethyl-8-quinolate) aluminum complex, tris (4-methyl-5-cyano-8-quinolate) Aluminum complex, bis (2-methyl-5-trifluoromethyl-8-quinolinolato) [4- (4-cyanophenyl) phenolate] aluminum complex, bis (2-methyl-5-cyano-8-quinolinolato) [4- (4-Cyanophenyl) phenolate] aluminum complex, tris (8-quino) Norato) scandium complex, bis [8- (para-tosyl) aminoquinoline] zinc complex and cadmium complex, 1,2,3,4-tetraphenylcyclopentadiene, poly-2,5-diheptyloxy-para-phenylene vinylene A low molecular weight light emitting material such as can be used.

  As a method for forming the organic light emitting layer 106, depending on the material, a resistance heating vapor deposition method, an electron beam vapor deposition method, a reactive vapor deposition method, an ion plating method, a dry film formation method such as a sputtering method, an ink jet printing method, a letterpress Although existing film forming methods such as a wet film forming method such as a printing method, a gravure printing method, and a screen printing method can be used, the present invention is not limited to these.

<Method for forming luminescent medium layer>
When the light emitting medium layer 108 is formed by a coating method, a relief printing method can be used. In particular, when using an organic light-emitting ink in which an organic light-emitting material is dissolved or stably dispersed in a solvent, the light-emitting layer 106 is separately applied to each light-emitting color, a relief printing method capable of patterning by transferring ink between partition walls is preferable. It is.
An example of a relief printing apparatus suitable for manufacturing an organic EL display device is shown in FIG. This relief printing apparatus 600 is used when pattern printing is performed on an organic light emitting ink made of an organic light emitting material on a substrate to be printed 602 on which a pixel electrode, a hole injection layer and a hole transport layer are formed, Plate copper 608 for pattern-printing organic luminescent ink on the surface of the substrate 602 placed on the stage 601 and organic diluted with a solvent on the convex portion of the plate 607 mounted on the plate copper 608 An anilox roll 605 for applying the luminescent ink.

Further, the relief printing apparatus 600 includes an ink chamber 604 having an ink supply portion that contacts the peripheral surface portion of the anilox roll 605, and an ink tank 603 that stores the organic light-emitting ink fed into the ink chamber 604, and is rotatable. In the vicinity of the supported anilox roll 605, a doctor 606 is provided to make the organic light-emitting ink supplied from the ink supply portion of the ink chamber 604 to the peripheral surface portion of the anilox roll 605 constant.
Accordingly, the organic light emitting ink transferred from the peripheral surface portion of the anilox roll 605 to the convex portion of the plate 607 is transferred onto the substrate 602 to be printed, whereby an organic light emitting layer is formed on the substrate 602 to be printed. Yes. In addition, it can form similarly using the said formation method also about the case where it coats and coats another luminescent medium layer.

<Electron injection layer>
After forming the organic light emitting layer 106, a hole blocking layer, an electron injection layer, or the like may be formed. These functional layers can be arbitrarily selected based on the size of the display panel of the organic EL display device. The material used for the hole blocking layer and the electron injection layer may be any material that is generally used as an electron transporting material, such as triazole, oxazole, oxadiazole, silole, and boron. A film can be formed by a vacuum deposition method using a material, an alkali metal such as lithium fluoride or lithium oxide, or a salt or oxide of an alkaline earth metal. In addition, these electron transport materials and these electron transport materials are dissolved in polymers such as polystyrene, polymethyl methacrylate, polyvinyl carbazole, etc., and toluene, xylene, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, methanol, ethanol, isopropyl alcohol , Ethyl acetate, butyl acetate, water or the like alone or in a mixed solvent to form an electron injection coating solution, which can be formed by a printing method.

<Counter electrode>
Next, the counter electrode 107 is formed. When the counter electrode 107 is used as a cathode, a material having high electron injection efficiency into the organic light emitting layer 106 and a low work function is used. Specifically, a metal such as Mg, Al, or Yb is used as an electrode material, or a compound such as Li, oxidized Li, or LiF is sandwiched by about 1 nm at the interface in contact with the light emitting medium layer 108, and Al having high stability and conductivity. Alternatively, a laminate of Cu and Cu may be used. In order to achieve both electron injection efficiency and stability, one or more metals such as Li, Mg, Ca, Sr, La, Ce, Er, Eu, Sc, Y, and Yb having a low work function, and Ag, Al An alloy system with a stable metal element such as Cu or Cu may be used. Specifically, alloys such as MgAg, AlLi, and CuLi can be used. The counter electrode 107 can be formed by a resistance heating vapor deposition method, an electron beam vapor deposition method, a reactive vapor deposition method, an ion plating method, or a sputtering method depending on the material.

<Sealing body>
Since the organic light emitting material of the organic light emitting layer 106 is easily deteriorated by moisture or oxygen in the atmosphere, a sealing body is usually provided for shielding from the outside. The sealing body can be manufactured, for example, by providing a resin layer on a sealing material.
The sealing material needs to be a base material having low moisture and oxygen permeability. Examples of the sealing material include ceramics such as alumina, silicon nitride, and boron nitride, glass such as alkali-free glass and alkali glass, quartz, and moisture resistant film. Examples of moisture-resistant films include films formed by CVD of SiOx on both sides of a plastic substrate, films with low permeability and water-absorbing films, or polymer films coated with a water-absorbing agent. The moisture vapor transmission rate of the moisture resistant film is preferably 10 ⁻⁶ g / m ² / day or less.

  As an example of the material of the resin layer, a photo-curing adhesive resin, a thermosetting adhesive resin, a two-component curable adhesive resin, or an ethylene ethyl acrylate (EEA) made of epoxy resin, acrylic resin, silicon resin, or the like Examples thereof include acrylic resins such as polymers, vinyl resins such as ethylene vinyl acetate (EVA), thermoplastic resins such as polyamide and synthetic rubber, and thermoplastic adhesive resins such as acid-modified products of polyethylene and polypropylene.

  Examples of methods for forming a resin layer on a sealing material include solvent solution method, extrusion lamination method, melting / hot melt method, calendar method, nozzle coating method, screen printing method, vacuum laminating method, hot roll laminating method, etc. Can be mentioned. A material having a hygroscopic property or an oxygen absorbing property may be contained as necessary. The thickness of the resin layer formed on the sealing material is arbitrarily determined depending on the size and shape of the organic EL display device to be sealed, but is preferably about 5 to 500 μm. In addition, although it formed as a resin layer on the sealing material here, it can also form directly on the organic EL element side.

  The organic EL display panel and the sealing body are bonded together in a sealing chamber. When the sealing body has a two-layer structure of a sealing material and a resin layer, and a thermoplastic resin is used for the resin layer, it is preferable to perform only pressure bonding with a heated roll. When a thermosetting adhesive resin is used, it is preferable to perform heat curing at a curing temperature after pressure bonding with a heated roll. In the case where a photocurable adhesive resin is used, curing can be performed by further irradiating light after pressure bonding with a roll.

<Aging>
Next, aging of the organic EL display device whose sealing is completed is performed. An organic compound having the lowest glass transition temperature among organic light emitting materials forming an organic light emitting layer in a state where a forward voltage is applied to the pixel electrode 102 and the counter electrode 107 so that the luminance in the pixel does not exceed 1 cd / m ^2. The organic EL display device is left in an atmosphere having a temperature lower than the glass transition temperature Tg of the light emitting material. The aging is completed when the luminous efficiency is reduced by approximately 10% to 30%. The current voltage at the time of aging may be a pulse current or a direct current, but in general, aging is performed in the same manner as in actual driving.
As an environment at the time of aging, since the glass transition temperature Tg of the organic light emitting material for organic EL that is generally used is less than 200 degrees, the environment is about 80 to 150 degrees using a general heating device. Left unattended. Moreover, it is preferable to carry out in the environment where the light of 600 nm or less was interrupted | blocked in order to prevent photodegradation of organic luminescent material.

[Example 1]
Examples of the present invention will be described below.
As the substrate, an active matrix substrate including a thin film transistor functioning as a switching element provided on a support and a pixel electrode formed thereabove was used. A substrate having a size of 200 mm × 200 mm, a diagonal size of 5 inches, and a pixel number of 320 × 240 is disposed in the center, and an extraction electrode and a contact portion are formed at the edge of the substrate.

  A partition wall was formed in such a shape as to cover an end portion of the pixel electrode provided on the substrate and partition the pixel. The partition walls were formed by forming a positive resist ZWD 6216-6 manufactured by Nippon Zeon Co., Ltd. on the entire surface of the substrate with a spin coater to a thickness of 2 μm, and then forming a partition wall having a width of 40 μm by photolithography. As a result, a pixel area of 960 × 240 dots and a pitch of 0.12 mm × 0.36 mm was defined.

Thereafter, the substrate was set on a sputtering film forming apparatus in which a molybdenum target was set, and a first carrier injection layer was formed on the display region in a pattern so as not to be formed on the extraction electrode or the contact portion. The sputtering conditions at this time were a pressure of 1 Pa, a power of 1 kW, and a flow rate ratio of oxygen to argon gas of 30%. The film thickness was 50 nm.
Next, the substrate on which the pixel electrode is formed is set in a printing machine, and an organic light emitting ink dissolved in toluene so as to have a concentration of 1% is aligned with the line pattern directly above the pixel electrode sandwiched between insulating layers. Then, a hole transport layer was formed on the pixel electrode by a relief printing method. At this time, a photosensitive resin plate corresponding to an anilox roll of 100 lines / inch and a pixel pitch was used as the plate 607 shown in FIG. The film thickness of the hole transport layer after printing and drying was 20 nm.

  Next, using an ink in which polyphenylene vinylene derivative, which is an organic light emitting material, is dissolved in toluene so as to have a concentration of 1%, an organic light emitting layer is formed in line with the line pattern directly above the pixel electrode sandwiched between the insulating layers. Was formed on the hole transport layer by letterpress printing. At this time, a photosensitive resin plate corresponding to an anilox roll of 150 lines / inch and a pixel pitch was used as the plate 607 shown in FIG. The thickness of the organic light emitting layer after printing and drying was 80 nm. This process was repeated three times in total to form an organic light emitting layer corresponding to the emission colors of R (red), G (green), and B (blue) in each pixel. The glass transition temperature of the organic light emitting material used this time was less than 200 degrees.

Then, calcium was formed into a film with a thickness of 10 nm by a vacuum evaporation method as an electron injection layer, and then an aluminum film with a thickness of 150 nm was formed as a counter electrode.
Thereafter, a glass plate as a sealing material was placed on the counter electrode so as to cover the entire light emitting region, and the adhesive was thermally cured at about 90 ° C. for 1 hour for sealing. An IC and a drive circuit were connected and modularized so as to input power and signals necessary for driving the active matrix drive type organic EL display panel thus obtained.

After that, as the aging of the organic EL display panel, after setting the pixel electrode and the counter electrode to a voltage of about 3.2 V so that the luminance in the pixel becomes about 10 cd / m ² , the temperature is set to 100 ° C. The organic EL display panel was left in the oven until the initial luminous efficiency decreased from 6 cd / A to 5 cd / A. The aging time at that time and the time until the luminance was reduced to half when the in-pixel luminance was set to 1000 cd / m ² after aging were measured. The measurement results are shown in Table 1.

[Example 2]
An organic EL display display panel similar to that in Example 1 was produced, and a voltage of about 3.2 V was applied to the pixel electrode and the counter electrode to set the luminance in the pixel to about 10 cd / m ^2. The organic EL display panel was left in an oven set at 0 ° C. until the initial current luminous efficiency decreased from 6 cd / A to 4.5 cd / A. The aging time at that time and the time until the luminance was reduced to half when the in-pixel luminance was set to 1000 cd / m ² after aging were measured. The measurement results are shown in Table 1.

[Example 3]
An organic EL display display panel similar to that in Example 1 was manufactured, and a voltage of about 3.2 V was applied to the pixel electrode and the counter electrode to set the luminance in the pixel to about 10 cd / m ^2. The organic EL display panel was left in an oven set at 0 ° C. until the initial current luminous efficiency decreased from 6 cd / A to 5 cd / A. The aging time at that time and the time until the luminance was reduced to half when the in-pixel luminance was set to 1000 cd / m ² after aging were measured. The measurement results are shown in Table 1.

[Example 4]
An organic EL display display panel similar to that in Example 1 was manufactured, and a voltage of about 3.2 V was applied to the pixel electrode and the counter electrode to set the luminance in the pixel to about 1 cd / m ^2. The organic EL display panel was left in an oven set at 0 ° C. until the initial current luminous efficiency decreased from 6 cd / A to 5 cd / A. The aging time at that time and the time until the luminance was reduced to half when the in-pixel luminance was set to 1000 cd / m ² after aging were measured. The measurement results are shown in Table 1.

[Example 5]
An organic EL display display panel similar to that in Example 1 was manufactured, and a voltage of about 3.2 V was applied to the pixel electrode and the counter electrode to set the luminance in the pixel to about 1 cd / m ^2. The organic EL display panel was left in an oven set at 0 ° C. until the initial current luminous efficiency decreased from 6 cd / A to 5 cd / A. The aging time at that time and the time until the luminance was reduced to half when the in-pixel luminance was set to 1000 cd / m ² after aging were measured. The measurement results are shown in Table 1.

[Comparative Example 1]
An organic EL display display panel similar to that in Example 1 was produced, and the organic EL display display panel was subjected to initial current emission in an oven set at a temperature of 100 ° C. with no voltage applied to the pixel electrode and the counter electrode. It was allowed to stand until the efficiency dropped from 6 cd / A to 5 cd / A. The aging time at that time and the time until the luminance was reduced to half when the in-pixel luminance was set to 1000 cd / m ² after aging were measured. The measurement results are shown in Table 1.

[Comparative Example 2]
An organic EL display display panel similar to that in Example 1 was fabricated, and a voltage of about 3.2 V was applied to the pixel electrode and the counter electrode to set the luminance in the pixel to about 10 cd / m ^2. The organic EL display panel was left in an oven set at 0 ° C. until the initial current luminous efficiency decreased from 6 cd / A to 5 cd / A. The aging time at that time and the time until the luminance was reduced to half when the in-pixel luminance was set to 1000 cd / m ² after aging were measured. The measurement results are shown in Table 1.

[Comparative Example 3]
An organic EL display display panel similar to that in Example 1 was manufactured, and a voltage of about 3.2 V was applied to the pixel electrode and the counter electrode to set the luminance in the pixel to about 1000 cd / m ² , and then room temperature of 25 ° C. The organic EL display panel was left in the temperature atmosphere until the initial current luminous efficiency decreased from 6 cd / A to 5 cd / A. The aging time at that time and the time until the luminance was reduced to half when the in-pixel luminance was set to 1000 cd / m ² after aging were measured. The measurement results are shown in Table 1.

In Examples 1 to 5, the luminance half time when the luminance within the pixel after aging is set to 1000 cd / m ² is 10,000 to 20000 h, whereas the aging treatment is performed without applying a voltage to the pixel electrode and the counter electrode. In Comparative Example 1, it can be seen from Table 1 that the half-life time of the luminance when the intra-pixel luminance after aging is set to 1000 cd / m ² is 7000 h. Further, in Comparative Example 2 in which the aging treatment is performed at a temperature higher than the glass transition temperature of the organic light emitting material, the luminance half time is 2000 h when the in-pixel luminance after aging is set to 1000 cd / m ^2. Can be seen from Table 1.

  Accordingly, as in Examples 1 to 5, the organic EL display panel is left in a temperature atmosphere lower than the glass transition temperature of the organic light emitting material with the voltage applied to the pixel electrode and the counter electrode. By aging the panel, stabilization of the layer interface is promoted, and early deterioration of the organic EL display display panel due to aging can be suppressed, thereby extending the life of the organic EL display device.

Further, as in Example 4 and Example 5, by applying a voltage at which the emission luminance of the organic light emitting layer is 1 cd / m ² or less to the pixel electrode and the counter electrode, the organic EL display panel is aged. For example, in comparison with Comparative Example 3 in which a voltage at which the light emission luminance of the organic light emitting layer is 1000 cd / m ² is applied to the pixel electrode and the counter electrode to perform aging of the organic EL display panel, the luminance within the pixel after aging is increased. Since the luminance half time when set to 1000 cd / m ² is significantly increased, early deterioration of the organic EL display panel due to aging can be more effectively suppressed, and the life of the organic EL display device can be extended. .

101 ... Substrate (support)
102: Pixel electrode (first electrode)
DESCRIPTION OF SYMBOLS 103 ... Partition 104 ... Carrier injection layer 105 ... Hole transport layer (carrier transport layer)
106 ... Organic light emitting layer 107 ... Counter electrode (second electrode)
DESCRIPTION OF SYMBOLS 108 ... Luminous medium layer 308 ... Substrate with TFT 309 ... Gate insulating film 310 ... Drain electrode 311 ... Active layer 312 ... Source electrode 313 ... Scan line 314 ... Gate electrode 600 ... Letterpress printing device 601 ... Stage 602 ... Substrate 603 ... Ink tank 604 ... Ink chamber 605 ... Anilox roll 606 ... Doctor 607 ... Letterpress 608 ... Plate cylinder 609 ... Ink layer

Claims (5)

A substrate, a plurality of pixel electrodes formed on the substrate, a counter electrode facing each of the pixel electrodes, and an organic light emitting layer made of an organic light emitting material between the counter electrode and the pixel electrode A method of manufacturing an organic EL display device including an organic EL display display panel including a light emitting medium layer,
After forming the organic EL display panel, the organic EL display display panel is applied with a forward voltage applied to the pixel electrode and the counter electrode so that the light emission luminance of the organic light emitting layer is 1 cd / m ² or less. Is left in an atmosphere having a temperature lower than the glass transition temperature of the organic light emitting material, and the organic EL display panel is aged. In the manufacturing method of the organic EL display device according to claim 1, before Symbol emission luminance of the organic light emitting layer of the organic EL display device which is characterized in that the aging of the organic EL display display panel to decrease 10% or more Production method. 3. The method of manufacturing an organic EL display device according to claim 1, wherein the aging of the organic EL display panel is performed under a light source that does not contain a wavelength component of 600 nm or less. . The organic EL display device manufacturing method according to claim 1, wherein at least the organic light emitting layer of the light emitting medium layer is formed by a wet film forming method or a dry film forming method. Manufacturing method of EL display device. 5. The method of manufacturing an organic EL display device according to claim 1, wherein the aging time of the organic EL display panel is 400 hours or more .

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