JP2014067868A - Organic el panel and manufacturing method of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organic EL panel and a manufacturing method of the same which can achieve high efficiency and improved chromatic purity of all colors.SOLUTION: An organic EL panel manufacturing method comprises: forming a first electrode 3 for each of red and green light-emitting pixels 15 and blue light-emitting pixels 16 on a substrate 2; arranging hole function layers 7 on first electrodes 3, respectively; providing red and green light-emitting layers 8 on the hole function layers 7 of the red and green light-emitting pixels 15; and sequentially providing a common function layer 10, a blue light-emitting layer 9, an electron function layer 13 and a second electrode 14 on the red and green light-emitting layers 8 and the hole function layers 7 in a whole area of a display region. The common function layer 10 is formed by co-evaporation of a hole transport material and an electronic transport material.

Description

  The present invention relates to an organic EL panel using an EL (electroluminescence) phenomenon of an organic thin film and a manufacturing method thereof.

An organic EL panel has a structure in which an organic light emitting layer exhibiting at least an EL phenomenon is sandwiched between an electrode as an anode and an electrode as a cathode, and when a voltage is applied between the electrodes (anode and cathode), Holes and electrons are injected into the organic light emitting layer, and the holes and electrons recombine in the organic light emitting layer, whereby the organic light emitting layer emits light.
In such an organic EL panel, for the purpose of increasing the luminous efficiency, a functional layer is provided between at least one of the anode and the organic light emitting layer and between the organic light emitting layer and the cathode. As each functional layer, at least one of a hole injection layer and a hole transport layer is provided between the anode and the organic light emitting layer, and an electron transport layer and an electron are provided between the organic light emitting layer and the cathode. At least one of the injection layers is provided, and these are appropriately selected.

  Materials used for these organic light emitting layers and functional layers are classified into low molecular materials and high molecular materials. Examples of using low molecular weight materials include, for example, copper phthalocyanine (CuPc) for the hole injection layer and N, N′-diphenyl-N, N′-bis (3-methylphenyl) -1, for the hole transport layer. 1'-biphenyl-4,4'diamine (TPD), tris (8-quinolinol) aluminum (Alq3) for the organic light emitting layer, 2- (4-biphenylyl) -5- (4-tert-butyl-) for the electron transport layer Phenyl) -1,3,4, -oxadizole (PBD), and those using LiF for the electron injection layer.

  Each layer made of these low molecular materials generally has a thickness within a range of 0.1 [nm] or more and 200 [nm] or less, and mainly in a vacuum deposition method such as a resistance heating method or a vacuum method such as a sputtering method. However, in the case of a partially soluble material, the film can be formed by a wet method like a polymer material. In addition, since there are a wide variety of low molecular weight materials, the combination is expected to improve luminous efficiency, luminous luminance, lifetime, and the like.

  On the other hand, examples of the polymer material include a material obtained by dissolving a low-molecular light-emitting dye in a polymer such as polystyrene, polymethyl methacrylate, and polyvinyl carbazole in an organic light-emitting layer, or a polyphenylene vinylene derivative (hereinafter also referred to as PPV). ), Polymer phosphors such as polyalkylfluorene derivatives (hereinafter also referred to as PAF), and polymer phosphors such as rare earth metals.

These polymer materials are generally dissolved or dispersed in a solvent, and have a film thickness in a range of 1 [nm] or more and 200 [nm] or less using a wet method such as coating or printing. A film is formed.
Organic thin films formed using polymer materials are less likely to crystallize and aggregate, and also have the advantage of preventing defects such as short circuits and dark spots because they cover other layers of pinholes and foreign matter. is there.

Here, as a material characteristic, the low molecular weight material is generally superior, and the lifetime is particularly long. Light emitting materials that are practical for polymer materials and red and green have been developed, but blue has not yet reached a practical level.
However, when comparing processes using materials, the dry method using a metal mask such as a low molecular material has difficulty in patterning and cost as the size and resolution become higher. However, there are many advantages such as coating accuracy, enlargement, and equipment costs.

Therefore, according to Patent Document 1, red and green organic light emitting materials are applied by patterning only on the red and green transparent pixel electrodes of the substrate by an ink jet method, and then a blue light emitting layer is formed on the entire surface by a vapor deposition method. It is disclosed that a blue light emitting layer of a low molecular material having excellent characteristics can be formed without patterning, and a full color organic EL display device can be provided.
However, when charge is passed in the state of this stacked structure, the holes injected into the red and green light emitting layers pass through, and there is a high probability that electrons and holes recombine in the blue light emitting layer. There is a possibility that the blue component will be mixed.

JP 2007-73532 A

  An object of the present invention is to provide an organic EL panel capable of improving the efficiency and color purity of all colors and a method for manufacturing the same.

  Among the present inventions, the invention described in claim 1 is such that a first electrode is formed for each of a red light emitting pixel, a green light emitting pixel, and a blue light emitting pixel formed on a substrate, and a hole injection layer is formed on the first electrode. Alternatively, a hole functional layer including at least one of the hole transport layers is provided, a red light emitting layer is formed on the hole functional layer of the red light emitting pixel, and green light is emitted on the hole functional layer of the green light emitting pixel. An electronic functional layer including a common functional layer, a blue light emitting layer, an electron transport layer, or an electron injection layer on the red light emitting layer, the green light emitting layer, and the hole functional layer over the entire display region. In the organic EL panel in which the second electrodes are provided in order, the common functional layer is formed by co-evaporation of a hole transport material and an electron transport material.

Further, in claim 2, triplet excitation energy levels of the hole transport material and the electron transport material are higher than triplet excitation energy levels of the red light emitting layer, the green light emitting layer, and the blue light emitting layer. The organic EL panel according to claim 1.
Moreover, in Claim 3, the triplet excitation energy level of the said hole transport material and the said electron transport material is 2.6 [eV] or more, The organic EL of Claim 1 or 2 characterized by the above-mentioned. A panel.

Further, in claim 4, the red light emitting layer and the green light emitting layer are formed using a wettable film forming material of a polymer material or a soluble low molecular material. It is set as the organic EL panel described in the above.
According to a fifth aspect of the present invention, the hole injection layer or the hole transport layer included in the hole functional layer has a stacked structure in which red light emitting pixels, green light emitting pixels, and blue light emitting pixels are different. The organic EL panel according to any one of claims 1 to 4.

Moreover, in Claim 6, it is a manufacturing method of the organic electroluminescent panel in any one of Claim 1 thru | or 5, Comprising: The said red light emitting layer and the said green light emitting layer are formed using a printing method, The said blue light emitting layer Is formed using a vapor deposition method, and it is set as the manufacturing method of the organic electroluminescent panel characterized by the above-mentioned.
According to a seventh aspect of the present invention, at least one of the hole injection layer or the hole transport layer included in the hole functional layer is formed or patterned on the entire display region by using a printing method. It is set as the manufacturing method of the organic electroluminescent panel of Claim 6.

  According to the present invention, the charge of each light emitting pixel is provided by providing a common functional layer in which a hole transport material and an electron transport material are formed by co-evaporation between the red light emitting layer and the green light emitting layer and the blue light emitting layer. The injection balance is improved, and all the colors are improved in efficiency and color purity.

It is sectional drawing which shows schematic structure of the organic electroluminescent panel in this embodiment. It is a schematic sectional drawing of the board | substrate with TFT of the organic electroluminescent panel which concerns on this embodiment. It is a figure which shows schematic structure of the relief printing apparatus used in order to form the organic light emitting layer of the organic electroluminescent panel which concerns on this embodiment.

(First embodiment)
Hereinafter, a configuration of an organic EL panel according to the present embodiment and a method for manufacturing the organic EL panel according to the first embodiment of the present invention (hereinafter referred to as “the present embodiment”) will be described with reference to the drawings. To do.

(Constitution)
FIG. 1 is a cross-sectional view showing a schematic configuration of an organic EL panel 1 in the present embodiment.
The configuration of the organic EL panel 1 includes a first electrode 3 partitioned for each of red, green, and blue light emitting pixels on a substrate 2, partition walls 4 that partition the pixels, a hole injection layer 5 and hole transport over the entire display area. The hole functional layer 7 composed of the layer 6, the red and green light emitting pixels 15 (one of the two light emitting pixels shown in FIG. 1 is a red light emitting pixel and the other is a green light emitting pixel). 8 (one of the two light-emitting layers shown in FIG. 1 is a red light-emitting layer and the other is a green light-emitting layer), and the common functional layer 10, blue light-emitting layer 9, electron injection layer 12 and The electronic functional layer 13 composed of the electron transport layer 11 and the second electrode 14 are formed in this order. The case where the organic EL panel of the present embodiment is an active matrix drive type in which the first electrode 3 is an anode and the second electrode 14 is a cathode will be described. The configuration of the organic EL panel 1 is not limited to the above configuration. For example, a passive matrix driving type in which each electrode (the first electrode 3 and the second electrode 14) is formed in a perpendicular stripe shape. An organic EL panel may be used.

(Detailed configuration of substrate 2)
Hereinafter, a detailed configuration of the substrate 2 will be described with reference to FIG. 1 and FIG. 2.
FIG. 2 is a cross-sectional view showing a detailed configuration of the substrate 2.
In the present embodiment, a case where a TFT substrate provided with the first electrode 3 and the partition 4 is used as the substrate 2 will be described as an example.
As shown in FIG. 2, the substrate 2 provided in the organic EL panel 1 of the present embodiment is provided with a thin film transistor (TFT) 20 and a first electrode (anode, pixel electrode) 3.

The thin film transistor 20 and the first electrode 3 are electrically connected.
The thin film transistor 20 is supported by a substrate (support) 2.
As the substrate 2, any material can be used as long as it has mechanical strength and insulation and is excellent in dimensional stability.
Here, examples of the material of the substrate 2 include plastic films and sheets such as glass, quartz, polypropylene, polyethersulfone, polycarbonate, cycloolefin polymer, polyarylate, polyamide, polymethyl methacrylate, polyethylene terephthalate, and polyethylene naphthalate. Can be used.

  The material of the substrate 2 is, for example, a metal oxide such as silicon oxide or aluminum oxide, a metal fluoride such as aluminum fluoride or magnesium fluoride, silicon nitride, aluminum nitride, etc. Translucent substrate made of metal nitride, silicon oxynitride such as silicon oxynitride, polymer resin film such as acrylic resin, epoxy resin, silicone resin, polyester resin, etc., aluminum, stainless steel, etc. It is possible to use a metal foil, a sheet, a plate, or the like.

Furthermore, as the material of the substrate 2, for example, a non-translucent base material in which a metal film such as aluminum, copper, nickel, stainless steel or the like is laminated on the above-described plastic film or sheet can be used. Here, the translucency of the substrate 2 may be selected according to which surface the light is extracted from.
The substrate 2 made of the above material is subjected to moisture-proofing treatment or hydrophobic treatment by forming an inorganic film or applying a fluororesin in order to avoid the intrusion of moisture into the organic EL panel 1. Is preferred. In particular, in order to avoid moisture intrusion into the red and green light emitting layers 8, it is preferable to reduce the moisture content and gas permeability coefficient in the substrate 2.

As the thin film transistor 20, a known thin film transistor can be used. Specifically, the thin film transistor 20 mainly includes an active layer 21 in which a source / drain region and a channel region are formed, and a gate insulating film 22 and a gate electrode 23.
Here, the structure of the thin film transistor 20 is not particularly limited, and examples thereof include a staggered type, an inverted staggered type, a top gate type, and a coplanar type.
The configuration of the active layer 21 is not particularly limited, and for example, an inorganic semiconductor material such as amorphous silicon, polycrystalline silicon, microcrystalline silicon, cadmium selenide, thiophene oligomer, poly (p- It can be formed of an organic semiconductor material such as ferylene vinylene).

The active layer 21 is formed using, for example, the methods described in the following (a) to (c).
(A) A method of laminating amorphous silicon by plasma CVD and ion doping. Specifically, using SiH ₄ gas, amorphous silicon is formed by LPCVD, amorphous silicon is crystallized by solid phase growth to obtain polysilicon, and then ion doping is performed by ion implantation.
(B) Amorphous silicon is formed by LPCVD using Si ₂ H ₆ gas or PECVD using SiH ₄ gas, annealed by a laser such as an excimer laser, and then amorphous silicon is crystallized to form poly After silicon is obtained, ion doping is performed by an ion doping method (low temperature process).
(C) The polysilicon is laminated by the low pressure CVD method or the LPCVD method, and thermally oxidized at 1000 [° C.] or more to form the gate insulating film 22, and the n + polysilicon gate electrode 23 is formed thereon, and then Ion doping by ion implantation (high temperature process).

As the gate insulating film 22, a film generally used as the gate insulating film 22 can be used. That is, as the gate insulating film 22, it is possible to use, for example, SiO ₂ formed by PECVD, LPCVD, or the like, or SiO ₂ obtained by thermally oxidizing a polysilicon film.
As the gate electrode 23, what is generally used as the gate electrode 23 can be used. That is, examples of the material of the gate electrode 23 include metals such as aluminum and copper (refractory metals such as titanium, tantalum, and tungsten), polysilicon, silicides of refractory metals, polycides, and the like.

Note that the structure of the thin film transistor 20 may be 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. Furthermore, two or more thin film transistors 20 may be arranged in one pixel.
Moreover, the organic EL panel 1 of this embodiment needs to be connected so that the thin film transistor 20 functions as a switching panel of the organic EL panel 1. For this reason, the drain electrode 24 of the thin film transistor 20 and the first electrode 3 are electrically connected. In FIG. 2, reference numeral 25 is assigned to the source electrode, reference numeral 26 is assigned to the scanning line, and reference numeral 27 is assigned to the transistor insulating film interposed between the thin film transistor 20, the first electrode 3, and the partition 4. doing.

(Detailed configuration of the first electrode 3)
Hereinafter, the detailed configuration of the first electrode 3 will be described with reference to FIGS. 1 and 2.
The first electrode 3 is formed by patterning on the substrate 2 and is partitioned by the partition walls 4 to form pixel electrodes corresponding to the respective pixels.
In the case of a transparent EL such as the organic EL panel 1 of this embodiment or a bottom emission method as a material of the first electrode 3, the first electrode 3 may be transparent in order to extract light from the first electrode 3 side. As required, conductive metal oxides such as ITO (indium tin composite oxide), IZO (indium zinc composite oxide), and AZO (zinc aluminum composite oxide) are used. It is also preferable to select a material having a high work function such as ITO.

  In addition, when the organic EL panel 1 is a top emission type in which light is extracted from above, a highly reflective metal material (Cr, A1, Ag, Mo, W, etc.) on the substrate, these metal oxides or metal materials After forming a single layer or a laminate of fine particle dispersion films in which fine particles are dispersed in epoxy resin, acrylic resin or the like, the first electrode 3 is formed using a conductive metal oxide such as ITO or IZO. In this case, since the film has a lower resistivity than the conductive metal oxide, the film functions as an auxiliary electrode, and emits light emitted from the red and green light-emitting layers 8 and blue light-emitting layers 9 described later. It is possible to make effective use of light by reflecting toward the two-electrode 14 side.

(Detailed configuration of partition 4)
Hereinafter, with reference to FIG. 1, the detailed structure of the partition 4 is demonstrated.
The partition wall 4 is formed on the substrate 2 and is formed so as to partition the light emitting region corresponding to the pixel by surrounding the periphery of the first electrode 3.
Here, in general, in the active matrix driving type organic EL panel 1, the first electrode 3 is formed for each pixel (sub-pixel), and each pixel tries to occupy as wide an area as possible. Therefore, the most preferable shape of the partition wall 4 formed so as to cover the end portion (side surface) of the first electrode 3 is basically a lattice shape that divides the first electrode 3 by the shortest distance.

Moreover, the material of the partition 4 contains an ethylenically unsaturated compound, a photoinitiator, and an alkali-soluble binder at least. Furthermore, the material of the partition walls 4 preferably contains a surfactant or the like, and also contains a solvent.
A preferable height of the partition wall 4 is in a range of 0.1 [μm] to 10 [μm], and more preferably in a range of 0.5 [μm] to 2 [μm]. . The reason is that if the height of the partition wall 4 is too high, the formation and sealing of the second electrode 14 (counter electrode) is hindered. If the height of the partition wall 4 is too low, the end of the first electrode 3 is completely covered. This is because, when the red and green light emitting layers 8 are formed, they are mixed with adjacent pixels.

(Detailed structure of hole functional layer 7)
Hereinafter, the detailed configuration of the hole functional layer 7 will be described with reference to FIGS. 1 and 2.
Since the hole functional layer 7 plays a role of efficiently injecting holes from the first electrode 3 to the red and green light emitting layers 8 and the blue light emitting layer 9, generally, the hole injecting layer 5 and the hole transporting layer 6 A laminated structure of two or more layers is used.
In addition, since the organic EL panel is composed of a red and green light emitting layer 8 using a material capable of a wet process and a blue light emitting layer 9 using a material capable of a vapor deposition method, In addition, the green light emitting pixel 15 and the blue light emitting pixel 16 may be formed with different materials and stacked structures of the hole functional layer 7.

  For example, polyaniline derivative, oligoaniline derivative, quinonediimine derivative, polythiophene derivative, polyvinylcarbazole (PVK) derivative, poly (3,4-ethylenedioxythiophene) (PEDOT), pyrrole derivative, aromatic amine, (triphenylamine) dimer Triarylamines such as derivatives (TPD), (α-naphthyldiphenylamine) dimer (α-NPD), [(triphenylamine) dimer] spirodimer (Spiro-TAD), 4,4 ′, 4 ″ -Tris Starburst such as [3-methylphenyl (phenyl) amino] triphenylamine (m-MTDATA), 4,4 ′, 4 ″ -tris [1-naphthyl (phenyl) amino] triphenylamine (1-TNATA) Amines and 5,5′-α-bis- {4- [bis (4- Methylphenyl) amino] phenyl} -2,2 ′: 5 ′, 2′-α-terthiophene (BMA-3T) and other oligothiophenes, aromatic amine-containing polymers, aromatic diamine-containing polymers, fluorene-containing Organic materials such as aromatic amine polymers, triazole-based, oxazole-based, oxadiazole-based, silole-based, and boron-based materials can be used.

_{Further, Cu 2 O, Cr 2 O} 3, Mn 2 O 3, FeO x, NiO, CoO, Pr2O 3, Ag 2 O, MoO 2, Bi 2 O 3, ZnO, TiO 2, SnO 2, ThO2, V 2 Inorganic materials such as transition metal oxides such as O ₅ , Nb ₂ O ₅ , Ta ₂ O ₅ , MoO ₃ , WO ₃ , and MnO ₂ , and nitrides and inorganic compounds containing one or more sulfides are also included. . However, the material is not limited to these.
The thickness of each layer included in the hole functional layer 7 is preferably in the range of 20 [nm] to 100 [nm]. This is because when the film thickness is thinner than 20 [nm], short defects are likely to occur, and when the film thickness exceeds 100 [nm], the current is reduced due to the increase in resistance.

(Detailed configuration of organic light emitting layer)
First, as a light emitting material, there are a low molecular material generally formed by a dry method and a polymer material formed by a wet method. The low molecular weight material has superior material properties compared to the high molecular weight material, and the difference in blue is particularly remarkable. However, there is a difficulty in patterning with higher definition and larger size. Here, in addition to the polymer material, a soluble low molecular weight material can also be used. However, the light-emitting characteristics of the soluble low-molecular material are affected by the solvent and the like, and there are problems such as inferior to the characteristics of the inherent low-molecular material and low viscosity compared to the high-molecular material, making it difficult to form a film.

For this reason, as a method for solving the above-mentioned problem, there is a structure in which the red and green light emitting layers 8 are formed by patterning by a wet method, and then the blue light emitting layer 9 is formed without patterning on the entire display region by a dry method. It is done. Thus, an organic EL panel that takes advantage of both the high-molecular material (or soluble low-molecular material) and the low-molecular material can be provided.
Examples of the polymer material include coumarin, perylene, pyran, anthrone, porphyrene, quinacridone, N, N′-dialkyl substituted quinacridone, naphthalimide, N, N′-diaryl substituted pyrrolopyrrole, Examples include iridium complex-based luminescent dyes dispersed in polymers such as polystyrene, polymethyl methacrylate, polyvinyl carbazole, polyarylene-based, polyarylene vinylene-based, and polyfluorene-based. Then, it is not limited to these materials.

  In addition to the above-described polymer materials, low molecular materials include 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-quinolato) 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-quinolinolato) scandium complex, bis [8- (para-tosyl) aminoquinoline] zinc complex and cadmium complex, 1,2,3,4-tetraphenylcyclopentadiene, poly-2,5-diheptyloxy Although -para-phenylene vinylene etc. are mentioned, in this embodiment, it is not limited to these materials. Further, when these materials are soluble, they may be used as soluble low molecular weight materials instead of polymer materials.

  Among the above light emitting materials, when used in a wet method, it is used as an organic light emitting ink by being dissolved or stably dispersed in a solvent. Here, examples of the solvent for dissolving or dispersing the light emitting material include toluene, xylene, acetone, anisole, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, and the like, or a mixed solvent thereof. In particular, 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 said organic light emitting ink as needed.

(Detailed configuration of red and green light emitting layer 8)
Hereinafter, the detailed configuration of the red and green light emitting layers 8 will be described with reference to FIG. In the organic EL panel, the red and green light emitting layers 8 are selected from the above-described polymer materials or soluble low molecular materials, and the hole functional layers 7 of the red and green light emitting pixels 15 are formed by a wet method. Patterning is formed on top.
The film thicknesses of the red and green light emitting layers 8 are preferably in the range of 20 [nm] or more and 200 [nm] or less from the viewpoint of light emission efficiency and lifetime.

(Detailed configuration of common function layer 10)
Hereinafter, the detailed configuration of the common functional layer 10 will be described with reference to FIG. The entire display area of the organic EL panel constructed as described above, that is, on the red and green light emitting layers 8 in the red and green light emitting pixels 15 and on the hole functional layer 7 in the blue light emitting pixels 16, the common functional layer 10. Is formed. The common functional layer 10 is a co-deposited film of a hole transport material and an electron transport material, and serves as a layer for controlling the flow of electric charges. In the organic EL panel in which the red and green light-emitting layers 8 and the blue light-emitting layer 9 are directly laminated as a comparative example, when charges are passed, holes injected into the red and green light-emitting layers 8 pass through, and the blue light-emitting layer 9, the probability of recombination of electrons and holes is high, and there is a possibility that a blue component is mixed in the region of the red and green light emitting pixels 15. However, by providing the common functional layer 10 co-evaporated by appropriately selecting the material type and concentration ratio of the hole transport material and the electron transport material between the red and green light emitting layers 8 and the blue light emitting layer 9, The injection balance can be easily controlled.

  The role of the common functional layer 10 is different for each color. The blue light emitting pixel 16 has a function of injecting holes from the hole functional layer 7 to the blue light emitting layer 9, and the red and green light emitting pixels 15 have a blue color. It is necessary to select a material so that holes are hard to be injected into the light emitting layer 9 and electrons are easily injected into the red and green light emitting layers 8. Therefore, as each transport material to be co-deposited, for example, a hole transport material having a good compatibility such as a small hole injection barrier to the blue light emitting layer 9 or a material having a high electron blocking property is selected. It is preferable to select a material having good compatibility such as a small electron injection barrier to the red and green light emitting layers 8 or a high hole blocking property.

  In recent years, phosphorescent materials are used for red and green light emitting materials, and delayed fluorescence generated via triplet-triplet annihilation is used for blue fluorescence characteristics. It is necessary to pay attention to the triplet excitation energy level of the light emitting layer 9. Therefore, when the triplet excitation energy level of the common functional layer 10 is lower than the triplet excitation energy level of the red and green light emitting layers 8 and the blue light emitting layer 9, it is generated in the red and green light emitting layers 8 and the blue light emitting layer 9. The triplet excitons may diffuse into the common functional layer 10. In order to suppress this, the triplet exciton energy levels of both the hole transport material and the electron transport material are higher than the triplet exciton energy levels of the red and green light emitting layers 8 and the blue light emitting layer 9. preferable. Furthermore, when the triplet exciton energy level is 2.6 [eV] or more for both the hole transport material and the electron transport material, it becomes higher than the triplet exciton energy level of a general light emitting material. More preferred.

  As hole transport materials used for co-evaporation, aromatic amine, (triphenylamine) dimer derivative (TPD), (α-naphthyldiphenylamine) dimer (α-NPD), [(triphenylamine) dimer] spirodimer ( Spiro-TAD) and the like triarylamines, 4,4 ′, 4 ″ -tris [3-methylphenyl (phenyl) amino] triphenylamine (m-MTDATA), 4,4 ′, 4 ″ -tris Starburst amines such as [1-naphthyl (phenyl) amino] triphenylamine (1-TNATA) and 5,5′-α-bis- {4- [bis (4-methylphenyl) amino] phenyl} -2 , 2 ′: 5 ′, 2′-α-terthiophene (BMA-3T) and the like.

  Examples of the electron transport material include compounds and complexes containing one or more nitrogen-containing heterocycles such as oxadiazole ring, triazole ring, triazine ring, quinoline ring, phenanthroline ring, pyrimidine ring, pyridine ring, imidazole ring carbazole ring, and the like. Can be mentioned. Specific examples include 1,10-phenanthroline derivatives such as bathocuproine and bathophenanthroline, benzimidazole derivatives such as 1,3,5-tris (N-phenylbenzimidazol-2-yl) benzene (hereinafter abbreviated as TPBI), Metal complexes such as bis (10-benzoquinolinolato) beryllium complex, 8-hydroxyquinoline Al complex, bis (2-methyl-8-quinolinato) -4-phenylphenolate aluminum, 4,4′-biscarbazole biphenyl, etc. Is mentioned. In addition, aromatic boron compounds, aromatic silane compounds, aromatic phosphine compounds such as phenyldi (1-pyrenyl) phosphine, bathophenanthroline, bathocuproine, 2,2 ′, 2 ″-(1,3,5-benzenetriyl ) -Tris (1-phenyl-1-H-benzimidazole) (abbreviated as TPBI), or a nitrogen-containing heterocyclic compound such as a triazine derivative. However, it is not limited to the above transport materials.

(Detailed configuration of the blue light emitting layer 9)
Hereinafter, the detailed configuration of the blue light emitting layer 9 will be described with reference to FIG. The blue light emitting layer 9 is formed on the entire surface of the display area on the common functional layer 10 by a dry method using a low molecular material having excellent characteristics.
The blue light emitting material is selected from the low molecular weight materials of the organic light emitting layer described above.

(Detailed configuration of the electronic functional layer 13)
Hereinafter, the detailed configuration of the electronic functional layer 13 including the electron injection layer 12 and the electron transport layer 11 will be described with reference to FIG. First, the electron transport layer 11 is made of a material having a high electron transport efficiency, a low work function or minimum unoccupied molecular orbital LUMO, and a high hole blocking property.
Examples thereof include compounds and complexes containing one or more nitrogen-containing heterocycles such as an oxadiazole ring, triazole ring, triazine ring, quinoline ring, phenanthroline ring, pyrimidine ring, pyridine ring, imidazole ring carbazole ring. Specific examples include 1,10-phenanthroline derivatives such as bathocuproine and bathophenanthroline, benzimidazole derivatives such as 1,3,5-tris (N-phenylbenzimidazol-2-yl) benzene (hereinafter abbreviated as TPBI), Metal complexes such as bis (10-benzoquinolinolato) beryllium complex, 8-hydroxyquinoline Al complex, bis (2-methyl-8-quinolinato) -4-phenylphenolate aluminum, 4,4′-biscarbazole biphenyl, etc. Is mentioned. In addition, aromatic boron compounds, aromatic silane compounds, aromatic phosphine compounds such as phenyldi (1-pyrenyl) phosphine, bathophenanthroline, bathocuproine, 2,2 ′, 2 ″-(1,3,5-benzenetriyl ) -Tris (1-phenyl-1-H-benzimidazole) (abbreviated as TPBI), or a nitrogen-containing heterocyclic compound such as a triazine derivative. However, it is not limited to these materials. The film thickness is preferably selected within the range of 0.1 [nm] or more and 50 [nm] or less in order to determine the optimum film thickness in consideration of carrier balance.

Next, the electron injection layer 12 is made of a material having a high electron injection efficiency and a small work function. In this case, specific materials include alkali metal and alkaline earth metal compounds such as Ca, Cs, LiF, and BaF ₂ . Besides this, as the material of the electron injection layer 12, for example, as an organic material, A1q _3, and the like.
The film thickness is preferably selected within the range of 0.1 [nm] or more and 50 [nm] or less in order to determine the optimum film thickness in consideration of carrier balance.

(Detailed configuration of the second electrode 14)
Hereinafter, the detailed configuration of the second electrode 14 will be described with reference to FIG.
The second electrode 14 is formed on the electronic functional layer 13 and faces the first electrode 3. Here, the second electrode 14 is formed so as to cover the entire display region, for example, in order to prevent water and oxygen from entering the electronic functional layer 13. As a material of the second electrode 14, for example, a single metal such as Mg, A1, or Yb is used.

(About sealed body)
The organic EL panel 1 can emit light by sandwiching light emitting materials (red and green light emitting layers 8 and blue light emitting layers 9) between electrodes (first electrode 3 and second electrode 14) and flowing current. However, organic light emitting materials are easily degraded by moisture and oxygen in the atmosphere. For this reason, normally, the organic EL panel 1 is provided with a sealing body (not shown) for shielding from the outside. Such a sealing body can be formed by providing a resin layer on a sealing material, for example.

As a material for the sealing material, it is necessary to use a base material having low moisture and oxygen permeability. Here, examples of the material for the sealing material include ceramics such as alumina, silicon nitride, and boron nitride, glass such as alkali-free glass and alkali glass, quartz, and a moisture-resistant film. Examples of the moisture resistant film include a film in which SiO _x is formed on both surfaces of a plastic substrate by a CVD method, a film having a low permeability and a water absorption property, or a polymer film coated with a water absorbing agent. . Here, the moisture permeability of the moisture-resistant film is preferably 10 ⁻⁶ [g / m ² / day] or less.

Examples of the material of 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 an epoxy resin, an acrylic resin, a silicon resin, or the like. ) 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. .
Here, 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 the thickness is within the range of 5 [μm] to 500 [μm]. Is preferred.

In the above description, the sealing body is formed as a resin layer on the sealing material. However, the sealing body can be directly formed on the organic EL panel 1 side.
Here, 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. On the other hand, when a thermosetting adhesive resin is used for the resin layer, it is preferable to perform heat curing at a curing temperature after pressure bonding with a heated roll. Moreover, when using a photocurable adhesive resin for a resin layer, after crimping | bonding with a roll, it can harden | cure by further irradiating light.

In addition, before performing sealing using the sealing material as described above, instead of using a thin film such as a silicon nitride film using a dry process such as an EB vapor deposition method or a CVD method, for example, as a passivation film. It is also possible to use a sealing body. Moreover, it is also possible to use the sealing body which combined these.
In this case, the thickness of the passivation film described above can be in the range of 100 [nm] to 500 [nm]. In particular, the thickness of the passivation film is preferably in the range of 150 [nm] or more and 300 [nm] or less, although it varies depending on the moisture permeability of the material, water vapor light permeability, and the like.
In addition, when the organic EL panel 1 has the above-described top emission type structure, it is necessary to consider light transmittance in addition to the above characteristics, so that the total average in the visible light wavelength region is 70 [%] or more. Any is suitable.

(Method for manufacturing organic EL panel 1)
Hereinafter, the manufacturing method of the organic EL panel 1 will be described with reference to FIG. When manufacturing the organic EL panel 1, first, an anode forming step of forming the first electrode 3 on the substrate 2 is performed. That is, the method for manufacturing the organic EL panel 1 includes an anode forming step. In the anode forming step, the first electrode 3 is 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, or the like depending on the material of the first electrode 3. A dry film forming method can be used. In addition to the dry film forming method, the first electrode 3 can be formed by a wet film forming method such as a gravure printing method or a screen printing method.

  Here, as a patterning method for partitioning the first electrode 3 for each of the red and green light-emitting pixels 15 and the blue light-emitting pixels 16, a mask vapor deposition method or a photolithography method is used depending on the material of the first electrode 3 and the film forming method. It is possible to use an existing patterning method such as a method, a wet etching method, or a dry etching method. Note that in the case where a substrate on which a thin film transistor is formed (see FIG. 2) is used as the substrate 2, the substrate 2 is formed so as to be conductive corresponding to the lower pixel.

  And after forming the 1st electrode 3 on the board | substrate 2, the partition formation process which forms the partition 4 surrounding the circumference | surroundings of the 1st electrode 3 on the board | substrate 2 is performed. That is, the method for manufacturing the organic EL panel 1 includes a partition forming step. In the partition formation step, as a method of forming the partition 4 on the substrate 2 on which the first electrode 3 is formed, for example, an inorganic film is uniformly formed on the substrate 2 on which the first electrode 3 is formed and masked with a resist. Then, a method of performing dry etching or a method of laminating a photosensitive resin on the substrate 2 on which the first electrode 3 is formed and forming a predetermined pattern by a photolithography method can be mentioned.

Further, if necessary, a water repellant is added to the material of the partition walls 4 or plasma or UV is irradiated to impart liquid repellency to the ink to the partition walls 4 after the partition walls 4 are formed. It is also possible.
After the partition wall 4 is formed, a hole functional layer 7 forming step is performed in which the hole injection layer 5 and the hole transport layer 6 included in the hole functional layer 7 are sequentially formed on the first electrode 3. That is, the method for manufacturing the organic EL panel 1 includes a hole functional layer 7 formation step.

In the hole functional layer 7 formation step, various coating methods such as a spin coater, a slit coat method, and a spray coat method, which are dissolved or dispersed in a solvent depending on the material of the hole injection layer 5 and the hole transport layer 6 A method of forming by a bar coating method, a dip coating method, a relief printing method, or a method of forming by a resistance heating vapor deposition method is used.
In addition to these methods, for example, a dry method such as 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 wet method such as a spin coating method, a sol-gel method, etc. A film forming method may be used.

Further, depending on the structure, the formation of the hole injection layer 5 and the hole transport layer 6 included in the hole functional layer 7 is different depending on the step of laminating two or more layers, the red and green light emitting pixels 15 and the blue light emitting pixels 16. Patterning.
Next, the red and green light emitting layers 8 are formed on the hole functional layers 7 formed in the red and green light emitting pixels 15 respectively. That is, the method for manufacturing the organic EL panel 1 includes a red and green light emitting layer 8 forming step.

  In the red and green light emitting layer 8 forming step, depending on the material of the red and green light emitting layer 8, there are existing wet film forming methods such as an ink jet printing method, a nozzle print printing method, a relief printing method, a gravure printing method, and a screen printing method. The film forming method is used. In particular, when the red and green light-emitting layers 8 are separately applied to the respective light emission colors (red and green) using an organic light-emitting ink in which a light-emitting material is dissolved in a solvent or stably dispersed, An ink jet method, a nozzle printing method, and a relief printing method that can transfer ink and pattern it are suitable.

  That is, in the red and green light emitting layer 8 forming step, an organic light emitting material that is a material of the red and green light emitting layers 8 is dissolved or dispersed in a solvent on the hole functional layer 7 of each of the red and green light emitting pixels 15. The luminescent ink is applied, and the red and green luminescent layers 8 are formed by patterning. In addition, the organic light emitting layer forming step is performed using any one of a printing method, an ink jet method, and a nozzle printing method. Note that the red and green light emitting layers 8 may be formed by using a method other than the film forming method described above.

  Here, the procedure for forming the red and green light emitting layers 8 by the above-described relief printing method will be described with reference to FIG. FIG. 3 is a diagram showing a schematic configuration of a relief printing apparatus 30 used in the relief printing method. As shown in FIG. 3, the relief printing apparatus 30 is an apparatus used when pattern printing is performed on an organic light emitting ink made of an organic light emitting material on the substrate 2 on which the first electrode 3 and the hole functional layer 7 are formed. There is an ink tank 31, an ink chamber 32, an anilox roll 33, and a plate cylinder 35 on which a relief plate 34 provided with projections is mounted.

The ink tank 31 contains organic luminescent ink diluted with a solvent, and the organic luminescent ink is fed into the ink chamber 32 from the ink tank 31. The anilox roll 33 is rotatably supported by the ink chamber 32 in contact with the ink supply unit of the ink chamber 32.
When the pattern printing is performed, the ink layer 36 of the organic light emitting ink supplied to the surface of the anilox roll 33 is formed with a uniform film thickness as the anilox roll 33 rotates. The ink of the ink layer 36 is transferred to the convex portion of the relief plate 34 mounted on the plate cylinder 35 that is driven to rotate in the vicinity of the anilox roll 33.

Then, a substrate to be printed (substrate 2) is installed on the stage 37, and the ink on the convex portion of the relief plate 34 is printed on the substrate 2, and a red color is formed on the substrate 2 through a drying process as necessary. And the green light emitting layer 8 will be formed.
Subsequently, a common functional layer 10 forming step is performed in which the common functional layer 10 is formed on the hole functional layer 7 of the blue light emitting pixel 16 and the red and green light emitting layers 8 of the red and green light emitting pixels 15. That is, the method for manufacturing the organic EL panel 1 includes a common functional layer 10 forming step.

The common functional layer 10 forming step is a step of performing co-evaporation of a hole transport material and an electron transport material, and is formed using a resistance heating vapor deposition method, an electron beam vapor deposition method, or the like depending on the material.
Next, a blue light emitting layer 9 forming step of forming the blue light emitting layer 9 on the common functional layer 10 is included. That is, the method for manufacturing the organic EL panel 1 includes a blue light emitting layer 9 forming step.
The blue light emitting layer 9 forming step is formed using a dry method such as a resistance heating vapor deposition method, an electron beam vapor deposition method, or a reactive vapor deposition method.

After the blue light emitting layer 9 is formed in this way, the electron transport layer 11, the electron injection layer 12, and the second electrode 14 are formed in this order, the electron transport layer 11 formation step, the electron injection layer 12 formation step, and the second electrode 14. Forming step. That is, the manufacturing method of the organic EL panel 1 includes an electron transport layer 11 formation step, an electron injection layer 12 formation step, and a second electrode 14 formation step.
In the electron transport layer 11 formation step, the electron injection layer 12 formation step, and the second electrode 14 formation step, a resistance heating method, an electron beam evaporation method, a reactive evaporation method, an ion plating method, a sputtering method, or the like is used depending on the material. Form.

A resin layer is provided over the sealing material.
Examples of the method for forming the resin layer include a solvent solution method, an extrusion lamination method, a melting / hot melt method, a calendar method, a nozzle coating method, a screen printing method, a vacuum laminating method, a hot roll laminating method, and the like. In this case, it is possible to contain a hygroscopic or oxygen-absorbing material as necessary.
Note that the bonding of the organic EL panel and the sealing body is performed in a sealing chamber.

[Example 1]
The organic EL panel 1 of the present embodiment includes, as a substrate 2, a thin film transistor 20 that functions as a switching panel provided on the substrate 2, and a first electrode (anode, pixel electrode) 3 formed thereon. An active matrix substrate was used.
The size of the active matrix substrate (substrate 2) is 200 [mm] × 200 [mm]. Further, the above active matrix substrate has a diagonal of 5 inches and a display having 320 × 240 pixels arranged in the center.

Then, an ITO film having a thickness of 150 [nm] was formed on the above active matrix substrate by sputtering, and this was used as the first electrode 3.
Further, the partition wall 4 was formed in a shape surrounding the first electrode 3 to partition the pixels. Here, when the partition 4 is formed, first, an acrylic photoresist material is formed to a thickness of 2 [μm] on the entire surface of the active matrix substrate, and then photolithography is performed on the photoresist material. A partition 4 having a width of 30 [μm] was formed on the first electrode 3 by the method. The width of each pixel was 80 [μm] × 150 [μm].

  Next, the hole injection layer 5 and the hole transport layer 6 were formed in this order on the first electrode 3 and the partition 4 formed as described above to form a hole functional layer 7. The hole injection layer 5 is a portion that becomes a display region using a 1 wt% aqueous dispersion of poly (3,4-ethylenedioxythiophene) and polystyrene sulfonic acid (hereinafter PEDOT / PSS) as an organic material using a slit coating method. A film was formed on the entire surface. The ink deposited in an extra portion other than the display area was wiped off with a waste cloth. The film thickness of the hole injection layer 5 after drying was 50 nm. Subsequently, the above-described polyvinyl carbazole derivative, which is a material of the hole transport layer 6, is dissolved on toluene so as to have a concentration of 0.5% on the hole injection layer 5 using the above-described ink. The active matrix substrate is set in a printing machine, printed on the first electrode 3 of the red and green light emitting pixels 15 and the blue light emitting pixels 16 in accordance with the line pattern by the relief printing method, and then the drying process is performed. went. At this time, 300 [line / inch] anilox roll and photosensitive resin plate were used. The target film thickness of the hole transport layer 6 was printed as 20 [nm].

  Next, red and green light emitting layers 8 are formed. As the red and green light emitting materials, polyphenylene vinylene derivatives having high electron transport properties are dissolved in toluene so that the concentration becomes 1 [%] to obtain an organic light emitting ink, and the above active matrix substrate is used in a printing machine. After setting, the red and green light emitting layers 8 were pattern-printed by the relief printing method for each line of the red and green light emitting pixels 15, and then the drying process was performed. At this time, 150 [lines / inch] anilox roll 42 and a water developing type photosensitive resin plate were used. Both the red and green light emitting layers 8 were printed with a target film thickness of 60 [nm].

Next, the common functional layer 10 is formed of a hole transport material and an electron transport material on the hole functional layer 7 in the blue light emitting pixel 16, and on the red and green light emitting layers 8 in the red and green light emitting pixels 15. It was formed by co-evaporation. Α-NPD was used as the hole transport material, and Alq ₃ was used as the electron transport material. For co-evaporation, a resistance heating vapor deposition method was used, and a film was formed so that the concentration ratio was α-NPD: Alq ₃ = 35%: 65%. The common functional layer 10 was formed over the entire display area, and the target film thickness was 20 [nm].
Next, the blue light emitting layer 9 was formed on the common functional layer 10. An anthracene derivative was used as the blue light emitting material. The film was formed by resistance heating vapor deposition using a metal mask, and the target film thickness was 30 [nm].

Next, an electronic functional layer 13 composed of the electron transport layer 11 and the electron injection layer 12 was formed. BAlq was selected as the electron transport material, LiF was selected as the electron injection material, and both were formed by resistance heating vapor deposition using a metal mask. The electron transport layer 11 was formed to have a thickness of 15 [nm], and the electron injection layer 12 was formed to have a thickness of 2 [nm].
Next, as the second electrode 14, an Al film was formed to a thickness of 150 nm by a vacuum deposition method using a metal mask. Then, a cap-type sealing glass and an adhesive were placed so as to cover the display area, and the adhesive was thermally cured at about 90 ° C. for 1 hour to be hermetically sealed to produce an active matrix driving type organic EL panel 1.

  In the active matrix driving type organic EL panel 1 manufactured in this way, by providing the common functional layer 10, the charge injection balance to the red and green light emitting layers 8 and the blue light emitting layer 9 is maintained, and the applied voltage is 7V. In particular, the blue light emitting pixel 16 has a light emission efficiency of 7 cd / A, the CIE chromaticity is x = 0.143, y = 0.171, the red light emission pixel 15 and the green light emission pixel 15 have a light emission efficiency of 14 cd / A, and the CIE color. Three colors: x = 0.30, y = 0.635, red and green light emitting pixels 15 with luminous efficiency of 8 cd / A, CIE chromaticity x = 0.64, y = 0.311 At the same time, high luminous efficiency and good color purity were achieved.

[Comparative Example 1]
An organic EL panel not corresponding to the organic EL panel according to the present invention was produced as Comparative Example 1 with respect to Example 1. In this comparative example, the common functional layer 10 was not formed, and the other selected materials and processes were deposited in the same manner as in Example 1.
The active matrix driving type organic EL panel of Comparative Example 1 manufactured in this way has a poor charge injection balance compared to Example 1, and the blue light emitting pixel 16 has a luminous efficiency of 7.5 cd when the applied voltage is 7V. / A, CIE chromaticity was x = 0.143, y = 0.165, but the green light emitting pixels of the red and green light emitting pixels 15 had a light emission efficiency of 9 cd / A, and the CIE chromaticity was x = 0.27. Y = 0.573, red light emission pixel 15 and red light emission pixel 15 with light emission efficiency of 5 cd / A, CIE chromaticity of x = 0.58, y = 0.30, green light emission efficiency reduction and red light emission efficiency, color The blue component was mixed with the color, resulting in poor characteristics.

1 Organic EL Panel 2 Substrate 3 First Electrode (Anode)
4 Partition 5 Hole injection layer 6 Hole transport layer 7 Hole functional layer 8 Red and green light emitting layer 9 Blue light emitting layer 10 Common functional layer 11 Electron transport layer 12 Electron injection layer 13 Electronic functional layer 14 Second electrode (cathode)
15 Red and green light emitting pixels 16 Blue light emitting pixels 20 Thin film transistor 21 Active layer 22 Gate insulating film 23 Gate electrode 24 Drain electrode 25 Source electrode 26 Scan line 27 Transistor insulating film 30 Letterpress printing device 31 Ink tank 32 Ink chamber 33 Anilox roll 34 Letterpress 35 Plate cylinder 36 Ink layer 37 Stage

Claims (7)

A hole functional layer including a first electrode formed for each of a red light emitting pixel, a green light emitting pixel, and a blue light emitting pixel formed on a substrate, and including at least one of a hole injection layer and a hole transport layer on the first electrode A red light emitting layer is formed on the hole functional layer of the red light emitting pixel, a green light emitting layer is formed on the hole functional layer of the green light emitting pixel, and the red light emitting layer on the entire display region, In the organic EL panel in which a common functional layer, a blue light emitting layer, an electron functional layer including at least one of an electron transport layer and an electron injection layer, and a second electrode are provided in order on the green light emitting layer and the hole functional layer.
An organic EL panel, wherein the common functional layer is formed by co-evaporation of a hole transport material and an electron transport material.   The triplet excitation energy level of the hole transport material and the electron transport material is higher than the triplet excitation energy level of the red light emitting layer, the green light emitting layer, and the blue light emitting layer. 1. The organic EL panel according to 1.   The organic EL panel according to claim 1 or 2, wherein a triplet excitation energy level of the hole transport material and the electron transport material is 2.6 [eV] or more.   4. The organic EL panel according to claim 1, wherein the red light emitting layer and the green light emitting layer are formed using a material capable of being wet-formed, such as a polymer material or a soluble low-molecular material. .   5. The hole injection layer or the hole transport layer included in the hole functional layer has a stacked structure different in red light emitting pixels, green light emitting pixels, and blue light emitting pixels. The organic electroluminescent panel in any one.   6. The method of manufacturing an organic EL panel according to claim 1, wherein the red light emitting layer and the green light emitting layer are formed using a printing method, and the blue light emitting layer is formed using a vapor deposition method. A method for producing an organic EL panel, comprising:   The at least one layer of the hole injection layer or the hole transport layer included in the hole functional layer is formed on the entire surface of the display region or patterned by using a printing method. Manufacturing method of organic EL panel.

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