JP2011076914A - Organic electroluminescent display panel and method of manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of manufacturing an organic EL display panel capable of canceling emission luminance unevenness of an organic EL element, and restraining acceleration of luminance degradation due to heat dissipation of a switching element making an on/off operation of the organic EL element. <P>SOLUTION: A plurality of first electrodes 102 are formed in a matrix alignment on a substrate 101 with organic EL elements formed, and first barrier ribs 103 for zoning the first electrodes 102 are formed in a lattice shape on the substrate 101, and then a light emitting medium layer 108 is formed on each first electrode 102. Thereafter, a second electrode 107 opposing to each first electrode 102 is formed on each light emitting medium layer 108. In that case, the second electrode 107 is formed on each light emitting medium layer 108, after a second barrier rib 105 is formed on each first barrier rib 103. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an organic EL display panel used in an organic electroluminescence (hereinafter referred to as “organic EL”) display device and a method for manufacturing the same.

An organic EL element used as a light-emitting element of an organic EL display panel is an element that has an organic light-emitting layer between two opposing electrodes, and emits light by passing a current through the organic light-emitting layer. Accordingly, the thickness of the organic light emitting layer is important in order to improve the light emission efficiency and reliability of such an organic EL element.
In addition, by arranging organic EL elements having different emission colors, a light emitting layer must be formed for each pixel in order to produce a full color organic EL display panel, and thus high-definition patterning is required.

  Further, the organic EL element has a carrier injection layer for injecting electrons or holes into the organic light emitting layer between the pixel electrode and the organic light emitting layer. There are two types of wet film forming methods. When using the wet film forming method, a polythiophene derivative decomposed into water is usually used. However, water-based inks are easily affected by the base, and it is very difficult to coat them uniformly. On the other hand, film formation by vapor deposition allows simple and uniform coating of the entire surface.

  As with the method for forming the carrier injection layer, there are two methods for forming the organic light-emitting layer: a dry film formation method and a wet film formation method, but one of the dry film formation methods that facilitates uniform film formation. When using a vacuum deposition method, it is necessary to perform patterning using a fine pattern mask. When an organic EL element is formed on a large substrate, it is very difficult to pattern the organic light emitting layer.

  Therefore, recently, as a method for forming a light emitting medium layer including an organic light emitting layer, a method in which a polymer material is dissolved in a solvent to form a coating liquid, and this is used to form an organic light emitting layer by a wet film forming method. It has become to. And when forming a luminescent medium layer by said method, it is common to laminate | stack a positive hole transport layer and an organic light emitting layer from the anode side, and it is set as a 2 layer structure, and an organic electroluminescent display panel is made into a color panel. As a method, an organic light emitting layer is coated using an organic light emitting ink in which organic light emitting materials having red (R), green (G), and blue (B) emission colors are dissolved or stably dispersed in a solvent. The method of dividing is known (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 two electrodes of the organic EL element. The carrier injection layer controls the injection amount of electrons when injecting electrons from the electrode into the organic light emitting layer, and controls the injection amount of holes when holes are injected from the other electrode into the organic light emitting layer. The layer inserted between the electrode and the organic light emitting layer. As the electron injection layer, an electron transporting organic material such as a metal complex of a quinolinol derivative or a relatively small work function such as an alkali metal such as Ca or Ba is used, and a plurality of layers having these functions are stacked. There is also. As the hole injection layer, those composed of TPD (triphenyleneamine derivative) (see Patent Document 3), those composed of a mixture of PEDOT (polyethylenedioxythiophene) and polystyrenesulfonic acid (PSS) (see Patent Document 4), A material made of an inorganic hole transport material (see Patent Document 5) is used, and is formed between the electrode and the organic light emitting layer for the purpose of increasing luminous efficiency.

  FIG. 7 is a diagram schematically showing the structure of a conventional organic EL display panel. In a conventional organic EL display panel, a plurality of first electrodes 102 are formed on a substrate 101 so as to form a matrix arrangement, and the first electrodes are formed. First partition walls 103 are formed in a lattice shape, and then a light emitting medium layer 108 including a carrier injection layer 104 and an organic light emitting layer 106 is formed on the first electrode 102, and then a first light emitting medium layer 108 is formed on the light emitting medium layer 108. A plurality of organic EL elements are formed on the substrate 101 by forming the two electrodes 107.

  In the organic EL display panel shown in FIG. 7, after the carrier injection layer 104 is formed on the substrate 101, the organic light emitting layer 106 is formed in a stripe shape to form the light emitting medium layer 108. When 106 is formed by vapor deposition, there is a problem that film thickness unevenness occurs due to unevenness of the opening line width of the shadow mask. Further, when the organic light emitting layer 106 is formed by a printing method, the film thickness of the organic light emitting layer 106 is often different for each line depending on the ink discharge amount or the transfer amount, and there is a problem that line-shaped light emission unevenness occurs. is there.

  As a means for solving this, there is a method of eliminating the initial luminance unevenness by feeding back the data-generated initial light emission unevenness to the current supply unit. However, since the supply power is common, the pixel electrode of the organic EL element is used. Since a high voltage is applied between the source and drain of a thin film transistor (TFT) that supplies current, and heat generated at that time is generated from the TFT in the vicinity of the pixel electrode, there is a problem of accelerating luminance deterioration of the display panel.

JP 2001-93668 A JP 2001-155858 A Japanese Patent No. 2916098 Japanese Patent No. 2851185 JP-A-9-63771

In the structure of the conventional organic EL element, there has been a problem that line-shaped light emission luminance unevenness occurs due to film thickness unevenness generated when the organic light emitting layer or the carrier injection layer is formed by a wet method.
Therefore, the present invention provides an organic EL display panel that can eliminate unevenness in light emission luminance of an organic EL element and can suppress acceleration of luminance deterioration due to heat generation of a TFT that turns on and off the organic EL element, and a method for manufacturing the same. It is an issue.

  In order to solve the above-mentioned problems, an invention according to claim 1 of the present invention is an active matrix drive organic electroluminescence display comprising a substrate and a plurality of organic electroluminescence elements formed on the substrate. A method for manufacturing a panel, wherein a plurality of first electrodes are formed on the substrate and a first partition wall for partitioning the first electrode is formed, and then one emission wavelength is formed in a stripe shape on the first electrode. When the second electrode opposite to the first electrode is formed on the light emitting medium layer after forming the light emitting medium layer including the light emitting layer formed by a wet process so that the light emitting layers are arranged, the first partition wall A second barrier rib parallel to the stripe direction of the light emitting layer is formed thereon, and then the second electrode divided by the second barrier rib is formed on the light emitting medium layer. .

According to a second aspect of the present invention, in the method of manufacturing an organic electroluminescence display panel according to the first aspect, the second partition wall having a tapered or rectangular longitudinal section is formed on the first partition wall. Then, the second electrode is formed on the light emitting medium layer.
The invention according to claim 3 of the present invention is the method of manufacturing an organic electroluminescence display panel according to claim 1 or 2, wherein the second partition is formed on the first partition made of an inorganic material, and then the first Two electrodes are formed on the light emitting medium layer.

  Invention of Claim 4 of this invention is a manufacturing method of the organic electroluminescent display panel as described in any one of Claims 1-3 WHEREIN: While forming a several 1st electrode on the said board | substrate, said 1st First partition walls for partitioning electrodes are formed at a height of 2 μm or less, and then a light emitting medium layer is formed on the first electrode, and then a second electrode facing the first electrode is formed on the light emitting medium layer In this case, the second barrier rib is formed on the first barrier rib with a height of 100 nm or more, and then the second electrode is formed on the light emitting medium layer.

The invention according to claim 5 of the present invention includes a substrate and a plurality of organic electroluminescent elements formed on the substrate, and each organic electroluminescent element is formed on the substrate. An electrode, a first partition formed on the substrate so as to partition the first electrode, and a light emission of one emission wavelength formed in a stripe shape on the first electrode partitioned by the first partition An active matrix driving type having a light emitting medium layer including a light emitting layer formed on each first electrode by a wet process so that the layers are arranged, and a second electrode facing the first electrode through the light emitting medium layer An organic electroluminescence display panel, wherein the second partition for dividing the second electrode on the first partition and changing the potential of the second electrode for each divided region is on the first partition Characterized in that it is formed so as to be parallel to the stripe direction of the light-emitting layer.
The invention according to claim 6 of the present invention is the organic electroluminescence display panel according to claim 5, characterized in that the vertical section of the second partition wall is tapered or rectangular.

  According to the first to sixth aspects of the present invention, the second electrode is not formed on the light emitting medium layer across the first partition, and the second electrode can be formed only on the light emitting medium layer. This makes it possible to adjust the light emission luminance of the organic EL element for each pixel by changing the potential of the second electrode every time it is divided, so that the light emission luminance unevenness of the organic EL element can be eliminated. . In addition, it is possible to consume the excess voltage of the power supply voltage that is also connected to places where luminance correction is not required, outside the panel without consuming the TFT, and the generated Joule heat can be separated from the display panel. Acceleration of luminance deterioration due to heat generation of the TFT can be suppressed.

It is a figure which shows typically the structure of the organic electroluminescent display panel which concerns on one Embodiment of this invention. It is a figure which expands and shows a part of organic EL display panel shown in FIG. It is a figure which shows an example of the TFT substrate at the time of applying this invention to an active matrix drive type organic electroluminescent display apparatus. It is a figure which shows typically the structure of an organic electroluminescence display panel in case two or more TFT is arrange | positioned in one pixel. It is a figure which shows schematic structure of a relief printing apparatus. It is a figure which shows the circuit structure of the organic electroluminescent display panel for demonstrating the Example and comparative example of this invention. It is a figure which shows an example of the structure of the conventional organic EL display panel.

  1 and 2 are diagrams schematically showing the structure of an organic EL display panel according to an embodiment of the present invention. As shown in FIG. 1, an organic EL display panel according to an embodiment of the present invention includes a substrate 101 made of an insulating material, and a plurality of first electrodes that form pixel electrodes of an organic EL element on the substrate 101. 102 is formed in a matrix arrangement, and a plurality of first partition walls 103 that partition the first electrode 102 are formed in a lattice shape.

On the surface of the first electrode 102 partitioned by the first partition 103, a carrier injection layer 104 of the organic EL element is formed. The carrier injection layer 104 forms a light emitting medium layer 108 together with the organic light emitting layer 106 formed on the surface thereof, and a second electrode 107 is formed on the upper surface of the light emitting medium layer 108.
The second electrode 107 forms a counter electrode of the organic EL element. The second electrode 107 emits light after forming the second partition wall 105 having a tapered or rectangular longitudinal section on the upper surface of the first partition wall 103. It is formed on the medium layer 108.

  As described above, the plurality of first electrodes 102 are formed in a matrix arrangement on the substrate 101 on which the organic EL element is formed, and the first partition walls 103 that partition the first electrodes 102 are formed in a lattice pattern, and then After forming the light emitting medium layer 108 including the carrier injection layer 104 and the organic light emitting layer 106 on the first electrode 102, when forming the second electrode 107 on the light emitting medium layer 108, the second electrode 107 is formed on the first partition 103. When the second electrode 107 is formed on the light emitting medium layer 108 after the partition 105 is formed, the second electrode 107 is not formed on the light emitting medium layer 108 across the first partition 103, and only on the light emitting medium layer 108. It is formed. This makes it possible to adjust the light emission luminance of the organic EL element for each divided unit region of the second electrode by changing the potential of the second electrode 107 for each divided unit. Light emission luminance unevenness can be eliminated.

In addition, a thin film transistor (TFT) is connected to each of the first electrodes 102 that form the pixel electrodes of the organic EL elements, and a power supply that can change the electrode potential is provided on the second electrode 107 divided on the first partition 103. By increasing the electrode potential of the second electrode 107 of the line that is connected every time and does not need to apply a high voltage, an excessive voltage is not applied to the TFT, so that the heat generation of the TFT can be suppressed. It becomes possible.
As the light emitting medium layer 108, an electron injection layer or a hole blocking layer (interlayer) is formed between the cathode side electrode and the organic light emitting layer 106, or the anode side electrode and the organic light emitting layer 106. A hole injection layer or an electron block layer (interlayer) may be formed between the two.

In the case of producing a full-color organic EL display panel, the organic light-emitting layer 106 constituting each pixel may be separately applied to, for example, three colors of R (red), G (green), and B (blue). .
Hereinafter, the configuration of the organic EL display panel according to the present invention will be described in detail. As an example for explaining the organic EL display panel according to the present invention, an active matrix driving type organic EL display device using the first electrode 102 as an anode and the second electrode 107 as a cathode will be described. In this case, the first electrode 102 is formed as a pixel electrode partitioned by the first partition 103 for each pixel, and the second electrode 107 is a counter electrode separated and formed by the second partition 105. The carrier injection layer 104 is a hole transporting hole injection layer, but may be an organic EL element having a reverse structure with the first electrode side as an anode. In this case, however, the carrier injection layer 104 is an electron injection layer having an electron transporting property.

<Board>
FIG. 3 is a diagram showing an example of a TFT-coated TFT substrate that can be used in the present invention. A thin film transistor (TFT) and a lower electrode (pixel electrode) 302 of the organic EL element are formed on the surface of the TFT substrate (back plane) 308 shown in FIG. Electrically connected.

  The TFT and the active matrix driving type organic EL display device formed thereon are supported by a substrate 308 as a support. Any material can be used as the support as long as it has mechanical strength and insulation and is excellent in dimensional stability. For example, plastic films or plastic sheets such as glass, quartz, polypropylene, polyethersulfone, polycarbonate, cycloolefin polymer, polyarylate, polyamide, polymethyl methacrylate, polyethylene terephthalate, polyethylene naphthalate, etc. can be used. Metal oxide layer made of silicon, aluminum oxide, etc., metal fluoride layer made of aluminum fluoride, magnesium fluoride, etc., metal nitride layer made of silicon nitride, aluminum nitride, etc., or metal oxynitride made of silicon oxynitride, etc. Translucent base material in which a layer or a polymer resin layer made of acrylic resin, epoxy resin, silicone resin, polyester resin, etc. is formed on a plastic film or plastic sheet, or Metal oxide layer, a metal nitride layer, a metal oxynitride layer, or the like can be used translucent substrate at least two layers laminated to a plastic film or plastic sheet of the polymer resin layer. In addition to the above, for example, a metal foil or metal sheet or metal plate made of aluminum, stainless steel, etc., or a metal film made of aluminum, copper, nickel, stainless steel, etc. laminated on a plastic film or plastic sheet. A light-sensitive substrate or the like can be used, and the light-transmitting property of the support may be selected depending on which surface the 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 formed over the substrate 308 which is a support, a known thin film transistor can be used. For example, as illustrated in FIG. 3, a thin film transistor 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 are formed by, for example, depositing amorphous silicon by plasma CVD, ion doping, forming amorphous silicon by LPCVD using SiH4 gas, and crystallizing amorphous silicon by solid phase growth to form polysilicon. Then, amorphous silicon is formed by ion doping by ion implantation, LPCVD using Si2H6 gas or PECVD using SiH4 gas, and annealed by a laser such as an excimer laser to crystallize amorphous silicon. After obtaining polysilicon, a method of ion doping by an ion doping method (low temperature process), laminating polysilicon by a low pressure CVD method or an LPCVD method, and thermally oxidizing at 1000 ° C. or more to form a gate insulating film, The gate electrode 308 of the n + polysilicon is formed over, 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, SiO2 formed by PECVD method, LPCVD method or the like, or SiO2 obtained by thermally oxidizing a polysilicon film. Etc. can be used.
As the gate electrode 314, one that is 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 refractory metal such as polysilicon. Examples thereof include silicide and polycide.

The thin film transistor formed over the substrate 308 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.
Further, since the thin film transistor formed over the substrate 308 needs to function as a switching element of the organic EL element, the drain electrode 310 of the transistor is electrically connected to the pixel electrode 302 of the organic EL element.

<Pixel electrode>
When the lower electrode (pixel electrode) 302 of the organic EL element is formed on the TFT substrate 308, the first electrode 102 which is a pixel electrode is formed on the substrate, and then patterned as necessary. The first electrode 102 is partitioned by the first partition wall 103 to become a pixel electrode corresponding to each pixel. As a material for the pixel electrode, metal oxide such as ITO (indium tin composite oxide), indium zinc composite oxide, zinc aluminum composite oxide, or metal materials such as gold and platinum can be used. Alternatively, 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 also be used.

When the pixel electrode 302 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, a metal material such as copper or aluminum may be provided as an auxiliary electrode in order to reduce the wiring resistance of the pixel electrode.
As the formation method of the pixel electrode 302, 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, etc. A wet film forming method such as a method can be used. Further, as a patterning method of the pixel electrode, 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 and 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 lower layer pixel.

<First partition wall>
The first partition 103 shown in FIG. 1 is formed in a grid pattern on the substrate 308 so as to partition the light emitting region corresponding to the pixel. In addition, as shown in FIG. 2, the first partition 103 is preferably formed so as to cover the end of the first electrode 102 that is a pixel electrode. In general, in an active matrix driving display device, a pixel electrode 302 is formed for each pixel (sub-pixel), and each pixel occupies as wide an area as possible, so that the end of the pixel electrode 302 is covered. The most preferable shape of the first partition 103 formed in the above is basically a lattice shape that divides each pixel electrode by the shortest distance.

  As in the conventional method, the first 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 the substrate and photolithography. The method of making a predetermined pattern by a method is mentioned. If necessary, a water repellent can be added, or plasma or UV can be irradiated to impart liquid repellency to the ink after formation. The preferred height of the first partition 103 is 0.1 μm to 10 μm, more preferably 0.5 μm to 2 μm.

<Second partition wall>
The second partition 105 shown in FIG. 1 is formed on the first partition 103 in parallel with the stripe direction of the light emitting layer described later. By forming in this way, it is possible to divide the second electrode into regions sandwiched between the second partitions as described later, and to control the applied voltage for each region. The interval between the second barrier ribs may be formed for each stripe of the light emitting layer as shown in FIG. 1, or as shown in FIG. 2, for example, R ( You may provide for each light emitting layer of three colors of red (red), G (green), and B (blue).
The same resin material and manufacturing method as the first partition can be applied to the second partition. The height of the second partition 105 is not particularly limited, but is preferably 100 nm or more when the height of the first partition 103 is 2 μm or less, for example.

<Carrier injection layer>
The carrier injection layer 104 shown in FIG. 1 is formed in a pattern or on the entire surface so as to cover the pixel electrode 302. 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 are dissolved or dispersed in a solvent, and are formed using various coating methods using a spin coater or the like and letterpress printing methods.

  When an inorganic material is used as the hole transport material, the inorganic material is Cu2O, Cr2O3, Mn2O3, FeOx (x to 0.1), NiO, CoO, Pr2O3, Ag2O, MoO2, Bi2O3, ZnO, TiO2, SnO2 or the like. , ThO2, V2O5, Nb2O5, Ta2O5, MoO3, WO3, MnO2, and other transition metal oxides and inorganic compounds containing one or more of these nitrides and sulfides can be used. However, the 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.

Depending on the material, the hole transport layer 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, a sputtering method, a dry film formation method, a spin coating method, a sol-gel method, or the like. However, the present invention is not limited to these, and a general film forming method can be used.
After forming the carrier injection layer 104, an interlayer can be formed. Examples of the material used for the interlayer 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. These materials are dissolved or dispersed in a solvent, and are formed using various coating methods using a spin coater or the like and letterpress printing methods.

<Organic light emitting layer>
The organic light emitting layer 106 shown in FIG. 1 is formed after the carrier injection layer 104 is formed on the pixel electrode 302. The organic light emitting layer 106 is a layer that emits light by passing a 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 carrier injection layer 104. In order to obtain multicolor display light, it can be suitably used by patterning as necessary. In the present invention, a light emitting layer having the same light emission color is formed in a line shape so as to be arranged in each pixel by applying to a pixel column using a wet process. That is, the light emitting layer is formed in a stripe shape.

  Examples of the organic light-emitting material forming the organic light-emitting layer 106 include 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, polymethylmethacrylate, polyvinylcarbazole, and polyarylene, polyarylene vinylene, and polyfluorene polymers Examples of the material include, but are not limited to, the present invention.

  These organic light emitting materials are dissolved or stably dispersed in a solvent to form an organic light emitting ink. Solvents 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 these, toluene, xylene, anisole, etc. An aromatic organic solvent is 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, dry film forming methods such as resistance heating vapor deposition method, electron beam vapor deposition method, reactive vapor deposition method, ion plating method, sputtering method, ink jet printing method, letterpress 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, but the present invention is not limited to these methods.

<Method for forming luminescent medium layer>
The light emitting medium layer 108 shown in FIG. 1 can be formed on the pixel electrode 302 by using, for example, a coating method. When the light emitting medium layer 108 is formed by a coating method, the following relief printing method is used. it can. In particular, when using an organic light-emitting ink in which an organic light-emitting material is dissolved or stably dispersed in a solvent, when the organic light-emitting layer 106 is separately applied to each light emission color, relief printing that can transfer and pattern ink between the first partition walls 103 The method is preferred.

FIG. 5 shows a schematic diagram of a relief printing apparatus 600 used when pattern printing is performed on a substrate to be printed 602 on which a pixel electrode, a hole injection layer, and an interlayer are formed. The relief printing apparatus 600 includes an ink tank 603, an ink chamber 604 for applying an organic light-emitting ink contained in the ink tank 603 to the surface of the anilox roll 605, and an organic light-emitting ink applied to the surface of the anilox roll 605 with a certain thickness. A doctor 606 formed on the ink layer 609 and a plate copper 608 for transferring the ink layer 609 formed by the doctor 606 to the printing substrate 602 on the stage 601, on the peripheral surface of the plate copper 608. A predetermined printing pattern is formed on the printing substrate 602 by the mounted relief plate 607, and an organic light emitting layer is formed on the printing substrate 602 by drying the printing substrate 602 after the relief printing.
Similarly, when the other light-emitting medium layer is applied as an ink, the organic light-emitting layer can be formed using the above method.

<Electron injection layer>
In the present invention, after the organic light emitting layer 106 is formed, a hole blocking layer, an electron injection layer, and the like can be formed. These functional layers can be arbitrarily selected from the size of the organic EL display panel and the like. 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>
In the present invention, after the organic light emitting layer 106 is formed, the second electrode 107 which is a counter electrode is formed on the light emitting medium layer 108. When the counter electrode 107 is a cathode, it is preferable to use a substance having a high electron injection efficiency into the organic light emitting layer 106 and a low work function (for example, a metal substance such as Mg, Al, Yb) as the counter electrode material. . In addition, a counter electrode may be formed by stacking Al or Cu having high stability and conductivity by sandwiching a compound such as Li, oxidized Li, or LiF at an interface in contact with the light emitting medium layer 108 for about 1 nm, In order to achieve both 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 stable Ag, Al, and Cu are used. An alloy system with a metal element such as may be used. Specifically, alloys such as MgAg, AlLi, and CuLi can be used.

As a method for forming the counter electrode 107, a resistance heating evaporation method, an electron beam evaporation method, a reactive evaporation method, an ion plating method, or a sputtering method can be used depending on the material.
In the present invention, it is necessary to pattern the counter electrode 107 in a line shape. However, since the second partition wall 105 having a taper shape or a rectangular shape is formed on the first partition wall 103, it is necessary to use a shadow mask. Therefore, patterning can be performed at a narrow pitch in a direction parallel to the organic light emitting layer 106, and the electrically separated counter electrode 107 can be formed on the light emitting medium layer 108.

<Sealing body>
As an organic EL display device, it is possible to emit light by sandwiching a light emitting material between electrodes and passing an electric current. However, since an organic light emitting material is easily deteriorated by moisture or oxygen in the atmosphere, it is usually externally connected. A sealing body for blocking is provided. 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 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 plastic substrates, films with low permeability and water-absorbing films, or polymer films coated with a water-absorbing agent. The water vapor transmission rate is preferably 10 −6 g / m 2 / day or less.

  Examples of the material for the resin layer include a photo-curing adhesive resin, a thermosetting adhesive resin, a two-component curable adhesive resin, and an ethylene ethyl acrylate (EEA) made of epoxy resin, acrylic resin, silicone resin, etc. 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 formed as a resin layer on the sealing material here, it can also be formed directly on the organic EL display device side.

The organic EL display device 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.
Finally, the drive circuit and display panel are connected. After the data driver and the gate driver are connected, the power source 504 is individually connected to the counter electrode 107 that is electrically separated through the power source voltage supply line 502.

Hereinafter, examples and comparative examples of the present invention will be described with reference to FIG.
[Example 1]
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 of 5 inches, and a pixel number of 320 × 240 is arranged in the center. An extraction electrode and a contact portion are formed at the substrate end.

A first partition wall was formed in such a shape as to cover the end 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. Then, using a negative resist ZPN1100 made by Nippon Zeon Co., Ltd., a resist film was formed to a thickness of 5 μm, exposed and developed so as to overlap the first partition and parallel to the patterning of the organic light emitting layer, and the side surface of the overhang shape A resist line having a pitch of 0.12 mm was formed as a second partition wall having a thickness of 0.12 mm.
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, using organic light-emitting ink in which polyphenylene vinylene derivative, which is an organic light-emitting material, is dissolved in toluene to a concentration of 1%, this substrate is set in a printing machine and directly above the pixel electrode sandwiched between insulating layers. The organic light emitting layer was printed by a relief printing method according to the line pattern. At this time, an anilox roll of 150 lines / inch and a photosensitive resin plate corresponding to the pixel pitch were used. 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.
Thereafter, calcium was deposited to a thickness of 10 nm as an electron injection layer by a vacuum deposition method, and then an aluminum film was deposited as a counter electrode to a thickness of 150 nm. The electron injection layer and the counter electrode were patterned in a line shape by the second partition wall and electrically separated.

  Thereafter, a glass plate was placed as a sealing material so as to cover the entire light emitting region, and sealing was performed by thermosetting the adhesive at about 90 ° C. for 1 hour. In order to drive the active matrix driving type organic EL display panel thus obtained, the drain electrode of the TFT 501 is connected to the anode (pixel electrode) of the organic EL element 503 as shown in FIG. The cathode (counter electrode) of the element 503 was connected to the power source 504 through the power supply voltage supply line 502 so that the potential of the counter electrode can be individually varied. When the potential of the counter electrode was set to 0V and the address of the luminance line unevenness was confirmed, a line having a low luminance of more than 20 lines could be confirmed. By adjusting so that it might become the following, it was able to be suppressed to the place where brightness nonuniformity cannot be judged visually. Further, the surface temperature of the panel at the time of driving the display panel was 30 ° C. with respect to the driving environment of 25 ° C.

[Example 2]
A substrate similar to that in Example 1 was used, and partition walls were formed so as to cover the ends of the pixel electrodes provided on the substrate and partition the pixels. 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. Then, using a negative resist ZPN1100 manufactured by ZEON Corporation, a resist film was formed to a thickness of 5 μm, exposed and developed so as to overlap the first partition wall and in parallel with the patterning of the organic light emitting layer. A resist line having a side face and a pitch of 0.36 mm was formed. The other film formation conditions are the same as in Example 1.

Thereafter, a sputtering film forming apparatus in which a molybdenum target was installed was installed, and a first carrier injection layer was formed in a pattern on the display region so as not to form a film 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.
Thereafter, a glass plate was placed as a sealing material so as to cover the entire light emitting region, and sealing was performed by thermosetting the adhesive at about 90 ° C. for 1 hour. In order to drive the active matrix driving type organic EL display panel thus obtained, the drain electrode of the TFT 501 is connected to the anode (pixel electrode) of the organic EL element 503 and the organic EL element 503 is driven as in the first embodiment. The cathode (counter electrode) was connected to the power source 504 via the power source voltage supply line 502 so that the potential of the counter electrode can be varied individually. When the potential of the counter electrode was set to 0V and the address of the luminance line unevenness was confirmed, it was confirmed that a line with a low luminance of slightly more than 30 lines was observed. By adjusting so that it might become the following, it was able to be suppressed to the place where brightness nonuniformity cannot be judged visually. Further, the surface temperature of the panel when the display panel was driven was 31 ° C. with respect to the driving environment of 25 ° C.

[Comparative example]
Using the same substrate as that of Example 1, only the first partition was patterned by the same method, and a film having a thickness of 50 nm was formed under the same sputtering conditions. Thereafter, film formation was performed in the same manner as in all the examples.
Thereafter, a glass plate was placed as a sealing material so as to cover the entire light emitting region, and sealing was performed by thermosetting the adhesive at about 90 ° C. for 1 hour. When the active matrix drive type organic EL display device thus obtained was driven, light emission was caused on the partition wall due to the leakage current, and the light emission efficiency was remarkably lowered. In order to drive the active matrix driving type organic EL display panel thus obtained, the drain electrode of the TFT 501 is connected to the anode (pixel electrode) of the organic EL element 503 as shown in FIG. The cathode (counter electrode) of the element 503 was connected to the power supply voltage supply line 502 to emit light. When the address of the luminance line unevenness is confirmed, about 30 low luminance lines can be confirmed in the same manner, and the common power supply voltage is increased by 3 V, and the line luminance is adjusted to 2% or less with respect to the normal part. By doing so, it was possible to suppress the luminance unevenness to a point where it could not be judged visually. The surface temperature of the panel at the time of driving the display panel at this time was 40 ° C. with respect to the driving environment of 25 ° C.
When the screen luminances of the display panels of Examples 1 and 2 and the comparative example were set to 300 cd / m 2 and the luminance lifetime was measured, the lifetime of Example 1: the lifetime of Example 2: the lifetime of Comparative Example = 1: 0.9: 0.6.

101 ... Substrate (support)
102. First electrode (pixel electrode)
DESCRIPTION OF SYMBOLS 103 ... 1st partition 104 ... Carrier injection layer 105 ... 2nd partition 106 ... Organic light emitting layer 107 ... 2nd electrode (counter electrode)
DESCRIPTION OF SYMBOLS 108 ... Light emitting medium layer 302 ... Pixel electrode 308 ... TFT substrate 309 ... Gate insulating film 310 ... Drain electrode 311 ... Active layer 312 ... Source electrode 313 ... Scanning line 314 ... Gate electrode 501 ... TFT
DESCRIPTION OF SYMBOLS 502 ... Power supply line 503 ... Organic EL element 504 ... Power supply 600 ... Letterpress printing apparatus 601 ... Stage 602 ... Substrate 603 ... Ink tank 604 ... Ink chamber 605 ... Anilox roll 606 ... Doctor 607 ... Letterpress 608 ... Plate cylinder 609 ... Ink layer

Claims (6)

A manufacturing method of an active matrix driving type organic electroluminescence display panel comprising a substrate and a plurality of organic electroluminescence elements formed on the substrate,
A plurality of first electrodes are formed on the substrate and a first partition wall for partitioning the first electrode is formed, and then a light emitting layer having one emission wavelength is arranged on the first electrode in a stripe shape. After forming a light emitting medium layer including a light emitting layer formed by a wet process, when forming a second electrode facing the first electrode on the light emitting medium layer, the stripe direction of the light emitting layer on the first barrier rib And forming the second electrode divided by the second barrier rib on the light emitting medium layer after forming the second barrier rib parallel to the organic EL display panel.   2. The method of manufacturing an organic electroluminescence display panel according to claim 1, wherein the second electrode is formed on the first barrier rib after the second barrier rib having a tapered or rectangular shape is formed on the first barrier rib. A method for producing an organic electroluminescence display panel, comprising: forming an organic electroluminescence display panel.   3. The method of manufacturing an organic electroluminescence display panel according to claim 1, wherein the second partition is formed on the first partition made of an inorganic material, and then the second electrode is formed on the light emitting medium layer. A method for producing an organic electroluminescence display panel.   In the manufacturing method of the organic electroluminescent display panel as described in any one of Claims 1-3, while forming a several 1st electrode on the said board | substrate, the 1st partition which divides said 1st electrode is 2 micrometers or less. After forming the light emitting medium layer on the first electrode and then forming the second electrode opposite to the first electrode on the light emitting medium layer, the second electrode is formed on the first partition. A method for producing an organic electroluminescence display panel, comprising: forming a partition wall at a height of 100 nm or more; and then forming the second electrode on the light emitting medium layer.   A substrate and a plurality of organic electroluminescent elements formed on the substrate, each organic electroluminescent element partitioning the first electrode with a first electrode formed on the substrate The first barrier ribs formed on the substrate and the first electrodes partitioned by the first barrier ribs are arranged on the first electrodes so that the light emitting layers having one emission wavelength are arranged in a stripe shape. An active matrix driving type organic electroluminescence display panel comprising: a light emitting medium layer including a light emitting layer formed by a wet process; and a second electrode facing the first electrode through the light emitting medium layer, A second partition for dividing the second electrode on the first partition and changing the potential of the second electrode for each of the divided regions is on the first partition in the stripe direction of the light emitting layer. The organic electroluminescent display panel, characterized in that it is formed such that the row.   6. The organic electroluminescence display panel according to claim 5, wherein the vertical cross section of the second partition wall is tapered or rectangular.

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