JP2016100280A - Organic EL panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the number of defaults on an anode surface which are caused by thermal stress associated with calcination by heating of a metal material layer for forming the anode to improve quality of an organic EL panel.SOLUTION: An organic EL panel 100 comprises in the following order and in a layered fashion: a substrate 1 consisting primarily of an inorganic material; an insulation layer 2 consisting primarily of resin; a first electrode layer 3 which contains an aluminum alloy containing aluminum, and nickel or cobalt and has a thickness of not less then 50 nm and less than 200 nm; a hole injection layer 5 composed of a transition metal oxide; an organic luminescent layer 8 including at least a luminescent layer which receives a carrier injected from the first electrode; and a second electrode layer 10 having polarity different from that of the first electrode layer 3. On a surface of the first electrode layer 3 on the metal oxide layer side, nickel of cobalt contacts the hole injection layer 5 at least in part and a thermal expansion coefficient of the insulation layer 2 is not less than 8 times and not more than 13 times larger than a thermal expansion coefficient of the substrate 1.SELECTED DRAWING: Figure 5

Description

  The present disclosure relates to an organic EL (Electro Luminescence) panel using an electroluminescence phenomenon of an organic material.

In recent years, a panel using a plurality of organic light-emitting elements arranged in a matrix on a substrate (hereinafter abbreviated as “organic EL panel”) has been put into practical use as a display panel used in a display device such as a digital television. Has been.
Each organic EL element is a current-driven light emitting element and has a basic structure in which a light emitting layer containing an organic light emitting material is disposed between a pair of electrodes of an anode and a cathode. A charge injection layer, a charge transport layer, and the like are interposed between the anode and the organic light emitting layer and between the cathode and the organic light emitting layer, if necessary. During driving, a voltage is applied between the pair of electrodes, and light is emitted in association with recombination of holes injected from the anode into the organic light emitting layer and electrons injected from the cathode into the light emitting layer. A hole injection layer for efficiently injecting holes into the organic light emitting layer is formed between the anode and the organic light emitting layer.

  In a general manufacturing process of an organic EL panel, an insulating layer made of a resin material is formed on a substrate on which a TFT layer is formed, and a metal material layer containing, for example, aluminum or an aluminum alloy is formed thereon as an anode material. The metal material layer is fired to form an anode. Further, a hole injection layer, an organic light emitting layer, and a cathode are formed thereon by using a metal oxide film made of, for example, tungsten oxide or molybdenum oxide (see, for example, Patent Document 1).

International Publication Number WO2012 / 001727

However, in the conventional organic EL panel, a minute defect that may be a cause of non-lighting pixels may occur on the formed anode surface, which has been a cause of deterioration in manufacturing quality of the organic EL panel.
This indication aims at providing the organic electroluminescent panel which reduced the number of the defects which arise on the anode surface, and improved quality in view of the said subject.

  In order to solve the above problems, an organic EL panel according to one embodiment of the present disclosure includes a substrate containing an inorganic material as a main component, an insulating layer containing a resin as a main component, and an aluminum alloy containing aluminum and nickel or cobalt. A first electrode layer having a thickness of 50 nm or more and less than 200 nm, a hole injection layer made of a transition metal oxide, an organic light emitting layer including at least a light emitting layer for receiving carriers injected from the first electrode, A first electrode layer and a second electrode layer having a polarity different from that of the first electrode layer, and at least part of the surface of the first electrode layer on the metal oxide layer side is made of nickel or cobalt. The thermal expansion coefficient of the insulating layer is 8 to 13 times the thermal expansion coefficient of the substrate.

  In the organic EL panel according to one embodiment of the present disclosure, it is possible to reduce the number of defects generated on the surface of the first electrode due to the thermal stress accompanying the heat firing of the metal material layer for forming the first electrode. The quality of the organic EL panel can be improved.

It is typical sectional drawing which shows the structure of the organic electroluminescent panel 100 which concerns on embodiment. It is a flowchart which shows a part of manufacturing process of the organic EL element of embodiment. 5 is a schematic cross-sectional view showing a part of the manufacturing process of the organic EL panel 100. FIG. 5 is a schematic cross-sectional view showing a part of the manufacturing process of the organic EL panel 100. FIG. 2 is a schematic cross-sectional view showing configurations of a substrate, an insulating layer, and an anode in an organic EL panel 100. FIG. 5 is a schematic cross-sectional view showing a part of the configuration of a substrate, an insulating layer, and an anode in an organic EL panel according to Comparative Example 1. FIG. It is the photograph which planarly viewed the organic EL panel 100 and the anode of Comparative Example 1. 6 is a distribution diagram showing experimental results of the organic EL panel 100 and the amoeba type voids of Comparative Example 1. FIG. It is the photograph which planarly viewed the anode of the organic electroluminescent panel which concerns on the comparative example 1 shown in FIG. 6 is a distribution diagram showing experimental results of the organic EL panel 100 and the amoeba type voids of Comparative Example 1. FIG. It is the photograph which planarly viewed the anode of the organic electroluminescent panel which concerns on the comparative example shown in FIG. 5 is a graph of experimental results showing the number of defects of the organic EL panel 100 and the anode of Comparative Example 1. 6 is a schematic cross-sectional view showing a configuration of an insulating layer and an anode in an organic EL panel according to Comparative Example 2. FIG. It is the photograph which planarly viewed the organic EL panel 100 when changing the thickness of a connection layer, and the anode of the organic EL panel which concerns on the comparative example 2. FIG. It is a graph of the experimental result which shows the defect distribution of the anode of the organic electroluminescent panel 100 when the thickness of a connection layer is changed, and the organic electroluminescent panel which concerns on the comparative example 2. FIG. It is a schematic diagram which shows the measurement position of the defect distribution of the anode of the organic electroluminescent panel in FIG. It is the photograph which planarly viewed the organic EL panel 100 when changing the thickness of the anode and the anode of the organic EL panel according to Comparative Example 2. It is a graph of the experimental result which shows the number of defects of the anode of the organic EL panel 100 and the organic EL panel which concerns on the comparative example 2 when changing the thickness of an anode. It is a graph of the experimental result which shows the relationship between the anode film thickness of the organic EL panel 100 and the organic EL panel which concerns on the comparative example 2, and efficiency, (a) is the light emission efficiency from the organic EL element 20c of a red subpixel, (B) shows the light emission efficiency from the organic EL element 20b of the green sub-pixel, and (c) shows the light emission efficiency from the organic EL element 20a of the blue sub-pixel. It is typical sectional drawing which shows the structure of the organic EL element 10X which comprises the conventional organic EL panel 100X. It is the photograph which planarly viewed the anode 105 of the organic EL element 10X, (a) shows a state where an amoeba type defect has occurred on the anode 105, and (b) shows a state where a minute dot-shaped defect has occurred. Show.

≪Background to the form for carrying out the invention≫
The inventor conducted an experiment in order to examine the cause of defects generated in the anode in the manufacturing process using a conventional organic EL element.
FIG. 20 is a schematic cross-sectional view showing the configuration of one organic EL element 10X constituting the conventional organic EL panel 100X described in Patent Document 1. As shown in FIG. As shown in FIG. 20, in the organic EL element 10 </ b> X, a TFT layer 1010 and a passivation film 102 are sequentially stacked on the upper surface of the substrate 101 in the Z-axis direction, and an insulating layer 103 is stacked thereon. . The substrate 101 is formed based on an insulating material such as alkali-free glass, soda glass, non-fluorescent glass, phosphate glass, borate glass, quartz, or aluminum. Insulating layer 103 is, for example, acrylic, polyimide, an organic insulating material or a sol-gel, is formed of an inorganic insulating material such as SiN or SiO _X. The TFT layer 1010 includes a gate electrode 1011, a drain electrode 1012, a source electrode 1013, a channel layer 1014, and a gate insulating film 1015, and is connected to the anode 105 through a contact hole (not shown).

  The organic EL element 10X includes a pixel portion 10a and a non-pixel portion 10b in the XY plane. In the pixel portion 10a, an anode 105 is formed on the insulating layer 103. In the non-pixel portion 10 b, the auxiliary electrode 106 is formed on the insulating layer 103. The anode 105 and the auxiliary electrode 106 are made of an alloy material containing nickel (Ni) or cobalt (Co) and mainly containing aluminum.

  Banks 107 are provided between adjacent anodes 105 and between adjacent anodes 105 and auxiliary electrodes 106, respectively. In the pixel portion 10a, a hole injection layer 108, an organic light emitting layer 109, an electron transport layer 110, and a cathode 111 are sequentially stacked on the anode 105. Among these, the electron transport layer 110 and the cathode 111 are formed continuously in the non-pixel portion 10b, and the cathode 111 and the auxiliary electrode 106 are electrically connected with the electron transport layer 110 interposed therebetween. ing. The upper surface of the cathode 111 is covered with a sealing layer 112.

Next, problems during manufacture of the organic EL element confirmed by the inventors will be described with reference to the drawings.
In the manufacturing process of the organic EL panel 100X, the TFT layer 101 and the passivation film 102 are sequentially laminated, and a metal material layer constituting the insulating layer 103, the anode 105, and the auxiliary electrode 106 is sequentially formed on the substrate, and then a baking process is performed. carry out. This is because the deposited metal material layer is fired to improve the film density (baking) of the anode 105 and the auxiliary electrode 106 to reduce resistance. Thereafter, banks 107 are formed between adjacent anodes 105 and between adjacent anodes 105 and auxiliary electrodes 106 based on a photolithography method, and then hole injection layer 108 is formed on anode 105. The anode 105 and the hole injection layer 108 are formed by etching and patterning based on a photolithography method. Thereafter, the organic light emitting layer 109, the electron transport layer 110, and the cathode 111 are laminated on the hole injection layer 108 by a coating method to complete the organic EL panel 100X.

Of the above manufacturing steps, in the step of firing the metal material layer of the anode 105 formed on the substrate, heating may cause minute defects on the surface of the anode 105. FIG. 21 is a photograph in plan view of the anode 105 of the organic EL element 10X. FIG. 21A shows a state in which an amoeba type defect (hereinafter referred to as “amoeba type void”) is generated on the anode 105. b) shows a state where a minute point-shaped defect (hereinafter referred to as a “point void”) has occurred.
When a hole is formed in the surface of the anode 105 by the amoeba type void and the point-like void (hereinafter collectively referred to as “void”), the organic light emitting layer 109 or the electron transport layer 110 is formed in the hole. The solution flows and a so-called breakage phenomenon occurs. As a result, a darkening phenomenon occurs in which the anode 105 and the cathode 111 are short-circuited and the pixel portion 10a is not lit.

  The inventor examined the cause of voids, and as a result, in the step of firing the metal material layer of the anode 105, peeling occurred at the interface between the insulating layer 103 and the anode 105 due to heating, and this peeling occurred on the surface of the anode 105. It was found to be the main cause of the outbreak. In view of this, the present inventors have intensively studied a device structure of an organic EL element capable of preventing the interface peeling between the insulating layer 103 and the anode 105 in the firing step, and have come up with the organic EL element according to the embodiment.

<< Summary of form for carrying out the invention >>
The organic EL panel according to this embodiment includes a substrate containing an inorganic material as a main component, an insulating layer containing a resin as a main component, aluminum and an aluminum alloy containing nickel or cobalt, and has a thickness of 50 nm or more and less than 200 nm. A first electrode layer, a hole injection layer made of a transition metal oxide, an organic light emitting layer including at least a light emitting layer for receiving carriers injected from the first electrode, and a first electrode having a polarity different from that of the first electrode. Two electrode layers stacked in that order, and at least part of the surface of the first electrode layer on the metal oxide layer side is in contact with the hole injection layer with nickel or cobalt, and heat of the insulating layer The expansion coefficient is 8 to 13 times the thermal expansion coefficient of the substrate.

In another aspect, the insulating layer and the first electrode layer may be in direct surface contact.
In another aspect, the material constituting the insulating layer may have a coefficient of thermal expansion of 30 × 10 ⁻⁶ / K or more and 60 × 10 ⁻⁶ / K or less.
In another aspect, the material constituting the substrate may have a coefficient of thermal expansion of 3.9 × 10 ⁻⁶ / K or more and 4.5 × 10 ⁻⁶ / K or less.

In another aspect, the material constituting the first electrode may have a coefficient of thermal expansion of 2.0 × 10 ⁻⁶ / K or more and 2.8 × 10 ⁻⁶ / K or less.
In another aspect, the insulating layer may have a thickness of 3000 nm to 5000 nm.
In another aspect, the resin may be one or more resins selected from the group consisting of polyamide, polyimide, and acrylic resin.

In another embodiment, an aluminum oxide layer may be formed on the surface of the first electrode layer on the hole injection layer side with nickel or cobalt deposited at least partially. Good.
In another aspect, the nickel or cobalt may be present in the form of islands in the aluminum metal oxide layer on the surface of the first electrode layer on the hole injection layer side.

In another aspect, the first electrode layer constitutes an anode, the second electrode layer constitutes a cathode, and the nickel or cobalt or an oxide composed thereof is a hole for injecting holes as carriers. It may be configured to have injectability.
In another aspect, the first electrode layer may be formed by depositing aluminum and an aluminum nickel alloy or aluminum cobalt alloy on the insulating layer by sputtering and then firing. .

<< Embodiment >>
1. Configuration The configuration of the organic EL panel 100 according to the embodiment will be described with reference to FIG. FIG. 1 is a cross-sectional view schematically showing a configuration of an organic EL panel 100 according to an embodiment as an aspect of the organic EL panel of the present disclosure. The organic EL panel 100 can constitute a display device with a drive control unit (not shown) connected thereto.

  In the organic EL panel 100, pixels (pixels) are arranged in a matrix along the upper surface of the substrate 1. Each pixel is composed of a set of adjacent organic EL elements of RGB sub-pixels of RGB. The organic EL elements 20a, 20b, and 20c are top emission types arranged on the substrate 1. The organic EL element 20a is a blue subpixel, the organic EL element 20b is a green subpixel, and the organic EL element 20c is red. Correspond to the sub-pixels.

The substrate 1 is formed with a TFT layer (not shown) for driving the organic EL elements 20a to 20c of the entire organic EL panel 100 in an active matrix system on the upper surface of a substrate body (not shown). It is configured to be covered with an insulating layer 2.
The substrate body is a substrate serving as a base portion of the organic EL panel 100, and includes alkali-free glass, soda glass, non-fluorescent glass, phosphate glass, borate glass, quartz, acrylic resin, styrene resin, or aluminum It is formed of an inorganic insulating material such as.

The insulating layer 2 is a resin film provided to insulate the TFT from the outside, and is formed of an organic material having excellent insulating properties, for example, an organic insulating material such as polyimide, polyamide, or acrylic resin material. The insulating layer 2 may be a planarizing layer having a function of planarizing the surface of the substrate 1 depending on the film thickness.
Next, the structure of the organic EL elements 20a to 20c will be described. On the insulating layer 2, an anode (first electrode) 3, a transparent electrode 4, a hole injection layer 5, an organic light emitting layer 8, an electron injection layer 9, a cathode 10, and a sealing layer 11 are sequentially stacked. In the present embodiment, the anode 3 is directly laminated on the upper surface of the insulating layer 2, so that the insulating layer 2 and the anode 3 are in direct surface contact.

Here, the anode 3 is made of a material having low electrical resistance including aluminum or an aluminum alloy, and is formed as a reflective anode having a thickness (film thickness) of preferably 50 nm to less than 200 nm, more preferably 75 nm to 150 nm. Aluminum or aluminum alloy is a highly conductive metal material having high light reflectivity and is suitable. As an example of the aluminum alloy, it is preferable to use an aluminum cobalt alloy (for example, Al ₉ Co ₂ ) or an aluminum nickel alloy (for example, AlNi ₃ ). In addition to aluminum-cobalt alloy or aluminum-nickel alloy, for example, aluminum-cobalt-germanium-lanthanum (Al-Co-Ge-La) alloy, aluminum-carbon-magnesium (Al-C-Mg) alloy, aluminum neodymium (Al-Nd) alloy, aluminum zirconium (Al-Zr) alloy, aluminum copper (Al-Cu) alloy, aluminum silicon (Al-Si) alloy, aluminum silicon-copper (Al-Si-Cu) alloy, etc. Also good.

The transparent electrode 4 is made of a conductive material containing indium, for example, a transparent electrode material such as ITO (indium oxide) or IZO (indium zinc oxide).
The film has a thickness of about 16 nm and covers the upper surface of the anode 3. The anode (reflective anode) 3 and the transparent electrode 4 may be used together as an anode.
The anode 3 and the transparent electrode 4 are separated and patterned for each of the organic EL elements 20a, 20b, and 20c constituting each subpixel.

  The hole injection layer 5 is a layer for efficiently injecting holes into the organic light emitting layer 8 from the anode 3 side, and is formed of, for example, a transition metal oxide film of molybdenum oxide (MoOx) or tungsten oxide (WOx). (X is a positive number). In addition, for example, conductivity such as oxides such as silver (Ag), chromium (Cr), vanadium (V), nickel (Ni), iridium (Ir), or PEDOT (a mixture of polythiophene and polystyrene sulfonic acid). A layer made of a polymer material may be used. The thickness of the hole injection layer 5 is preferably in the range of about 0.1 to 20 nm. The hole injection layer 5 is separately patterned for each of the organic EL elements 20a, 20b, and 20c.

When the hole injection layer 5 is composed of an oxide of a transition metal, a plurality of levels can be obtained by taking a plurality of oxidation numbers. As a result, hole injection is facilitated and driving voltage is reduced. be able to. In particular, it is desirable to use tungsten oxide (WO _X ) from the viewpoint of stably injecting holes and supporting the generation of holes and process resistance. In this embodiment, tungsten oxide (WOx) (WOx: about 10 [nm]) is employed. However, the layer thickness is not limited to this. For example, the layer thickness of tungsten oxide (WOx) can be in the range of 5 [nm] to 30 [nm].

  On the hole injection layer 5, a bank 6 made of an insulating material is provided so as to partition at least between adjacent sub-pixels. The bank 6 may have a so-called pixel bank structure in which the organic light emitting layers 8 of the individual organic EL elements 20a, 20b, and 20c are individually partitioned, or the organic light emitting layer 8 of the organic EL elements 20a, 20b, and 20c of the same light emission color. Alternatively, a line bank structure may be used in which a group is partitioned into stripes.

The bank 6 is formed of an organic material such as an insulating resin, and is subjected to an etching process, a baking process, and the like in the forming process. Examples of organic materials include acrylic resins, polyimide resins, novolac type phenol resins, and the like.
In the region partitioned by the bank 6, a hole transport layer 7 and an organic light emitting layer 8 are laminated.

  The hole transport layer 7 serves to transport holes from the anode 3 side and inject them into the organic light emitting layer 8. Specific examples of the material include 4,4′-bis [N- (naphthyl) -N-phenyl-amino] biphenyl (α-NPB or α-NPD), N, N′-bis (3-methylphenyl). And triarylamine compounds such as-(1,1'-biphenyl) -4,4'-diamine (TPD). It can be manufactured by a wet process using a solution containing these materials.

  The organic light emitting layer 8 has a function of emitting light by injecting holes and electrons and recombining them to generate an excited state. The organic light emitting layer 8 can also be formed by a wet method. The material is, for example, an oxinoid compound, a perylene compound, a coumarin compound, an azacoumarin compound, an oxazole compound, an oxadiazole compound, a perinone compound, a pyrrolopyrrole compound, a naphthalene compound described in Patent Publication (JP-A-5-163488), Anthracene compound, fluorene compound, fluoranthene compound, tetracene compound, pyrene compound, coronene compound, quinolone compound and azaquinolone compound, pyrazoline derivative and pyrazolone derivative, rhodamine compound, chrysene compound, phenanthrene compound, cyclopentadiene compound, stilbene compound, diphenylquinone compound, Styryl compound, butadiene compound, dicyanomethylenepyran compound, dicyanomethylenethiopyran compound, fluorescein compound , Pyrylium compounds, thiapyrylium compounds, serenapyrylium compounds, telluropyrylium compounds, aromatic ardadiene compounds, oligophenylene compounds, thioxanthene compounds, anthracene compounds, cyanine compounds, acridine compounds, metal complexes of 8-hydroxyquinoline compounds, 2-bipyridine compounds It is preferably formed of a fluorescent substance such as a metal complex of the above, a Schiff salt and a group III metal complex, an oxine metal complex, or a rare earth complex.

On the organic light emitting layer 8, an electron injection layer 9, a cathode (second electrode) 10 and a sealing layer 11 are continuous over the organic EL elements 20 a, 20 b, and 20 c of the entire panel beyond the upper part of the bank 6. Is formed.
The electron injection layer 9 has a function of transporting electrons injected from the cathode 10 side to the organic light emitting layer 8. For example, it is composed of barium, phthalocyanine, lithium fluoride, or a combination thereof.

The cathode 10 is made of a light transmissive material such as ITO or IZO (indium zinc oxide). In addition, for example, a layer including an alkali metal, an alkaline earth metal, or a halide thereof and a layer including silver may be stacked in this order.
The sealing layer 11 has a function of suppressing exposure of the organic light emitting layer 8 and the like to moisture and air, and is made of a light-transmitting material such as SiN (silicon nitride) or SiON (silicon oxynitride). It is preferable to form.

2. Manufacturing Method A method for manufacturing the organic EL panel 100 will be described with reference to FIGS. 2, 3, and 4. FIG. 2 is a flowchart showing a part of the manufacturing process of the organic EL element of the embodiment. 3 and 4 are schematic cross-sectional views illustrating a part of the manufacturing process of the organic EL panel 100.
First, a substrate body is prepared. Based on the reactive sputtering method, a TFT layer is formed on the surface of the substrate body to form a substrate 1 (S1).

Next, an insulating layer 2 having a thickness of about 4 μm is formed so as to cover the TFT layer (S2, FIG. 3A). The insulating layer 2 can be formed by applying a known photosensitive organic material (for example, a siloxane copolymer type photosensitive polyimide). The insulating layer 2 also functions as a planarizing layer for planarizing the surface of the substrate 1 if the thickness is about 4 μm as in this embodiment.
Next, a metal material layer 3X is thinly formed on the insulating layer 2 (on the substrate 1) by a sputtering method using a metal material such as aluminum or an aluminum alloy (S3, FIG. 3B).

Next, a transparent conductive film 4X made of a transparent electrode material such as ITO or IZO is formed on the surface of the metal material layer 3X based on a vacuum film formation method (S4, FIG. 3C).
Next, a metal material of a transition metal compound (such as molybdenum or tungsten) is formed by a vacuum film formation method or a reactive sputtering method to form a metal oxide film 5X (S5, FIG. 3 (d)).

  Next, after each film formation of the metal material layer 3X, the transparent conductive film 4X, and the metal oxide film 5X, a firing process of the metal material layer 3X is performed (S6, FIG. 3E). This is because alloy particles formed of aluminum and nickel or cobalt in the metal material layer 3X are deposited on the surface of the hole injection layer 5 side, and at least part of the surface of the anode 3 on the hole injection layer 5 side is nickel. Alternatively, cobalt is in contact with the hole injection layer 5. As a result, the entire surface of the anode 3 on the side of the hole injection layer 5 is covered with an oxide of aluminum, which is an insulator, and the current between the anode 3 and the hole injection layer 5 is prevented from being interrupted. The structure which contacts with the layer 5 through nickel or cobalt can be taken. The anode 3 and the hole injection layer 5 are electrically connected.

  The baking process of the anode (metal material layer 3X) is performed when all of the metal material layer film formation, the transparent conductive film film formation, and the metal oxide film film formation are performed. The firing temperature is higher than each step before the firing step (for example, a range of 200 ° C. to 230 ° C.), and the firing is performed for 15 minutes or more, preferably for 40 minutes or more. By performing this firing step, the metal material layer 3X with improved film density and reduced electrical resistance can be obtained. Moreover, the film density of the transparent conductive film 4X is also improved by this baking step, and the electrical resistance can be reduced. Thus, the manufacturing process can be facilitated by firing the metal material layer 3X and the transparent conductive film 4X together.

Note that the firing step of the anode (metal material layer 3X) may be performed after the metal material layer is formed, but before the transparent conductive film is formed and the metal oxide film is formed.
Next, a photosensitive resist R is applied on the metal oxide film based on the photolithography method, and patterning of the metal oxide film 5X is performed (S7). First, a photosensitive resist film R is provided on the upper surface of the metal oxide film 5X, and exposure is performed from above the pattern mask (FIG. 3F). When a positive photosensitive resist is used for the photosensitive resist film R, the pattern mask shields light from the portion where the anode 3 is to be formed, and forms an opening so as to expose other portions. Thereafter, resist development is performed using a developer (resist developer) made of an alkaline aqueous solution (FIG. 4A).

Next, the metal oxide film 5X is patterned based on dry etching to form the hole injection layer 5 (S8, FIG. 4B).
Next, the metal material layer 3X and the transparent conductive film 4X are wet-etched to form the transparent electrode 4 and the anode 3 (S9, FIG. 4C), and are collectively etched using the same etching solution. As the etchant, for example, a hydrofluoric acid based mixed acid can be used.

  Thereafter, the resist that is no longer needed is peeled off (S10, FIG. 4 (d)). This completes the patterning of the anode, transparent electrode, and hole injection layer. The anode 3, the transparent electrode 4, and the hole injection layer 5 may be formed using any of dry etching and wet etching. These may be etched individually or in combination with any one of them.

Next, a photosensitive resist material or a resist material containing a fluorine-based or acrylic-based material is prepared as a bank material. This material is applied onto the hole injection layer 5 by a spin coating method and patterned based on a photoresist method. Thereafter, the bank 6 is formed by heat curing (S11).
Next, ink containing a hole transport layer material is dropped into the region between the banks 6 based on, for example, an ink jet method. The hole transport layer 7 is formed by drying this ink.

  Further, an ink containing an organic EL material is dropped on the upper surface of the hole transport layer 7 and the ink is dried to form the organic light emitting layer 8. The ink application method may be any of a dispenser method, a nozzle coating method, a spin coating method, intaglio printing, letterpress printing, and the like. The ink is preferably dried by, for example, vacuum drying. After ink drying, baking is performed in a nitrogen atmosphere. The average thickness of the organic light emitting layer 8 is, for example, 70 nm.

Next, a thin film made of barium is formed based on the vacuum deposition method so as to cover the organic light emitting layer 8 and the bank 6. Next, based on the co-evaporation method, a film of compound Alq mixed with barium is formed with a predetermined thickness (for example, 20 nm) to form the electron injection layer 9.
Next, on the electron injection layer 9, for example, based on a plasma coating method, an IZO thin film is formed to a thickness of, for example, 100 nm to form the cathode 10.

Next, the sealing layer 11 is formed on the cathode 10 using a material such as SiN or SiON based on a vacuum deposition method or the like.
Thus, the organic EL panel 100 is completed.
3. Next, the structure of the principal part of the organic EL panel 100 will be described.

  FIG. 5 is a schematic cross-sectional view showing configurations of the substrate 1, the insulating layer 2, and the anode 3 in the organic EL panel 100. As described above, the organic EL panel 100 includes the insulating layer 2 that is an insulating layer mainly composed of a resin on the upper surface of the substrate 1 whose main component is an inorganic material, and aluminum and nickel on the upper surface of the insulating layer 2. Or it has the structure provided with the anode 3 containing the aluminum alloy containing cobalt.

As shown in FIG. 5, the linear expansion coefficient of the substrate 1 is 3.9 to 4.5 × 10 ⁻⁶ / K, and the thickness is, for example, about 500 μm. The insulating layer 2 has a linear expansion coefficient of 30 to 60 × 10 ⁻⁶ / K, about 46 × 10 ⁻⁶ / K in the present embodiment, and a thickness of about 4 μm. Furthermore, the linear expansion coefficient of the anode 3 containing aluminum and an aluminum alloy containing nickel or cobalt is about 24 × 10 ⁻⁶ / K, and the thickness is about 50 to 200 nm, for example. That is, in the organic EL panel 100, between the substrate 1, the first electrode layer 3, and the insulating layer 2 between the substrate 1 having the smallest thermal expansion coefficient and the first electrode layer 3 having an intermediate thermal expansion coefficient. The insulating layer 2 having the largest coefficient of thermal expansion is interposed. And it is preferable that the thermal expansion coefficient of the insulating layer 2 which is an insulating layer is 8 to 13 times the thermal expansion coefficient of the substrate 1.

  As described above, in the organic EL panel 100, the firing process of the metal material layer 3X for forming the anode 3 is performed (S6, FIG. 3E). This is because nickel or cobalt in the metal material layer 3X is deposited on the surface on the hole injection layer 5 side, and at least part of the surface of the anode 3 on the hole injection layer 5 side is nickel or cobalt. It is for making it contact. As a result, in the firing process, thermal stress due to thermal expansion occurred in the substrate 1, the insulating layer 2, and the anode 3, and in the conventional organic EL panel, this was a factor in generating voids in the anode 3.

  On the other hand, in the organic EL panel 100, the thermal expansion coefficient is between the substrate 1, the anode 3, and the insulating layer 2 having the smallest thermal expansion coefficient and the anode 3 having the intermediate thermal expansion coefficient. The insulating layer 2 having the largest is interposed. In addition, the thermal expansion coefficient of the insulating layer 2 is set to 8 times or more and 13 times or less than the thermal expansion coefficient of the substrate 1. Thereby, the void which arises on the surface of the anode 3 resulting from the thermal stress accompanying the heat baking for forming the anode 3 can be suppressed.

Hereinafter, the effect of reducing the number of defects on the anode surface of the organic EL panel 100 according to the embodiment will be described based on experimental results.
4). Effect Confirmation Test 4.1 Reduction of the number of defects on the anode surface <Test 1>
In order to confirm the effect of reducing the number of defects on the anode surface of the organic EL panel 100 according to the embodiment, the following effect confirmation test was performed. The test was performed using the organic EL panel 100 according to the embodiment and Comparative Example 1 in which the anode 3 was directly formed on the substrate 1 without providing the insulating layer 2 in the same configuration as the organic EL panel 100.

  FIG. 6 is a schematic cross-sectional view showing a part of the configuration of the substrate and the anode in the organic EL panel according to Comparative Example 1. Comparative Example 1 has a configuration in which the anode 3 is directly laminated on the upper surface of the substrate 1 in the same configuration as the organic EL panel 100. The organic EL panel 100 is different from the organic EL panel 100 in that the insulating layer 2 is not provided between the upper surface of the substrate 1 and the lower surface of the anode 3, and the other configuration is the same as that of the organic EL panel 100.

As described above, the substrate 1 is mainly composed of an inorganic material, the linear expansion coefficient of the substrate 1 is 3.9 to 4.5 × 10 ⁻⁶ / K, and the thickness is, for example, about 500 μm. The anode 3 includes aluminum and an aluminum alloy containing nickel or cobalt. The anode 3 has a linear expansion coefficient of about 24 × 10 ⁻⁶ / K and a thickness of, for example, about 50 to 200 nm. As described above, Comparative Example 1 has a configuration in which the substrate 1 made of an inorganic material and having a relatively low coefficient of thermal expansion is in direct surface contact with the anode 3 made of metal and having a relatively high coefficient of thermal expansion. Yes.

  In Test 1, first, the anode thickness of both was changed from 50 nm to 200 nm, and the state of voids on the anode surface was compared. FIG. 7 is a photograph of the organic EL panel 100 and the anode of Comparative Example 1 viewed in plan. As shown in FIG. 7, in Comparative Example 1, it was confirmed that in the samples b1, b2, and b3 having anode thicknesses of 50 nm, 75 nm, and 100 nm, one amoeba type void was generated on the anode. Further, in Comparative Example 1, it was confirmed that the point-like voids were generated almost entirely on the anode in the samples b3, b4, and b5 having the anode thicknesses of 100 nm, 150 nm, and 200 nm. On the other hand, in the organic EL panel 100 according to the embodiment, it was not confirmed that amoeba type voids or dot voids were generated on the anode in the samples a1 to a5 having the anode thickness of 50 nm to 200 nm.

  Next, the anode thicknesses of the organic EL panel 100 and the comparative example 1 were changed from 50 nm to 200 nm, and the distribution states of the amoeba type voids in the organic EL panel were compared. 8 and 10 are distribution diagrams showing the experimental results of the organic EL panel 100 and the amoeba-type voids of Comparative Example 1. FIG. FIG. 8 shows the results measured after the anode film formation, and FIG. 10 shows the results measured after the bank firing. In these figures, a rectangular frame described in each condition represents an organic EL panel, and a plot in the frame indicates the position of an amoeba type void.

  As shown in FIG. 8, in samples b1, b2, and b3 having anode thicknesses of 50 nm, 75 nm, and 100 nm, many amoeba type voids are generated over the entire panel, and in other samples, amoeba type voids are generated. However, it was confirmed that the number was relatively small. FIG. 9 is a plan view of the anodes of samples b1, b2, and b3 according to Comparative Example 1 shown in FIG. As shown in FIG. 9, it was confirmed that a large number of amoeba-type voids were generated on the anode in samples b1 and b2, a single location was observed in b3, and a large number of dotted voids were generated in sample b3. This amoeba type void is considered to be a void generated during firing. According to the inventors' investigation, pitting corrosion of aluminum is promoted by alkali, but contact between aluminum and alkali does not occur in the anodic patterning step. Therefore, although FIG. 8 shows the measurement results after the anode patterning, it is considered that the amoeboid type voids are not pitting corrosion caused by the etching chemical, but are generated during firing.

  In addition, as shown in FIG. 10, in the samples b1, b2, and b3 having anode thicknesses of 50 nm, 75 nm, and 100 nm, many amoeba type voids are generated over the entire panel, and in other samples, amoeba type voids are generated. However, the number was confirmed to be relatively small. FIG. 11 is a photograph in plan view of the anodes of samples b1, b2, b3, and b4 according to Comparative Example 1 shown in FIG. As shown in FIG. 11, it was confirmed that a large number of amoeba-type voids were generated on the anode in samples b1 and b2, a single location on b3, and a large number of spot-like voids on samples b3 and b4. From the results shown in FIG. 10, it is considered that the amoeboid voids increased during the erosion by the developer due to the amoeba voids generated during firing.

  Note that amoeba-type voids tend to occur in thin films, and point-like voids tend to occur in thick portions. This is considered due to the difference in the state of thermal stress relaxation. That is, in a thin film, stress tends to be intensively relaxed during heating, and in a thin film, a hole is generated between atoms at a weakly bonded portion, resulting in an amoeba type void. Once perforation due to an amoeba type void occurs, the stress is relaxed and no other small point void is formed. On the other hand, in the case of a thick film, it tends to be relatively difficult for perforation to occur. Therefore, it is considered that a large number of point-like voids are evenly generated in minute portions weak by thermal stress.

  FIG. 12 is a graph of experimental results showing the number of defects in the organic EL panel 100 and the anode of Comparative Example 1. In Comparative Example 1, in samples b1, b2, and b3 having anode thicknesses of 50 nm, 75 nm, and 100 nm, amoeba type voids are generated about 1000 or more after anode patterning and about 4000 or more after bank firing. In Comparative Example 1, about 400 or more dot-like voids are generated in samples b3, b4, and b5 having anode thicknesses of 100 nm, 150 nm, and 200 nm. On the other hand, in the organic EL panel 100 according to the embodiment, only a very small amount (about 200 or less) of both the amoeba type voids and the pointed voids are generated in the samples a1 to a5 whose anode thickness is 50 nm to 200 nm.

As described above, in the organic EL panel 100 according to the embodiment, the anode 3 has a thickness in the range of 50 nm to 200 nm, compared with the comparative example 1 in which the anode 3 is directly formed on the substrate 1 without providing the insulating layer 2. It was confirmed that the number of surface defects (amoeba type voids and point voids) was small.
<Reason why organic EL panel 100 can suppress generation of defects on the anode surface as compared with Comparative Example 1>
As the reason why the organic EL panel 100 has a smaller number of defects on the anode surface than the comparative example 1, the following is assumed.

As described above, the linear expansion coefficient of the substrate 1 made of an inorganic material is 3.9 to 4.5 × 10 ⁻⁶ / K, whereas the linear expansion coefficient of the anode 3 made of metal is about 24 × 10 ^−6. It is relatively large with / K. Therefore, in the state during heating in the firing step (S6), the amount of thermal strain of the metal material layer 3X calculated from the heating temperature is relatively large with respect to the value of the substrate 1. However, as described above, in Comparative Example 1, since the substrate 1 and the anode 3 (metal material layer 3X) are in direct surface contact, the relative displacements are restricted to each other. Therefore, thermal stress is generated inside the substrate 1 and the anode 3 in the vicinity of the interface. Then, during the heating in the firing step (S6), the thermal stress is alleviated by breaking the interatomic bond of the metal material layer 3X at a part of the interface due to the thermal stress inside the substrate 1 and the anode 3. The At this time, in the above-mentioned amoeba type void, the thermal stress is relieved by being concentrated by one relatively large void. In a point-like void, thermal stress is relieved at a plurality of locations by a large number of small voids.

Thereafter, in the state where the heating in the firing step (S6) is completed and cooled, the substrate 1 and the anode 3 contract each other. At that time, a hole-like defect (void) may occur in the thickness direction of the anode 3 at a location where the interatomic bond of the anode 3 is cut at the interface between the substrate 1 and the anode 3.
The above is considered to be the reason why defects (voids) on the anode surface occur in Comparative Example 1.
On the other hand, in the organic EL panel 100, it is considered that the interatomic bond of the anode 3 is not broken at the interface between the insulating layer 2 and the anode 3, and defects (voids) on the anode surface are suppressed.

As described above, the linear expansion coefficient of the insulating layer 2 containing resin as a main component is 30 to 60 × 10 ⁻⁶ / K, which is relatively large with respect to both the substrate 1 and the anode 3. That is, in the organic EL panel 100, between the substrate 1, the first electrode layer 3, and the insulating layer 2 between the substrate 1 having the smallest thermal expansion coefficient and the first electrode layer 3 having an intermediate thermal expansion coefficient. The insulating layer 2 having the largest coefficient of thermal expansion is interposed. Therefore, in the state during heating in the firing step (S6), the amount of thermal strain of the insulating layer 2 calculated from the heating temperature is larger than the amount of thermal strain of the metal material layer 3X. However, the actual amount of thermal strain of the insulating layer 2 is offset by the amount of thermal strain of the substrate 1 having a small amount of thermal strain calculated from the heating temperature. That is, the insulating layer 2 and the substrate 1 are restrained from relative displacement. As a result, the displacements of the metal material layer 3X and the insulating layer 2 are substantially equal, and the thermal stress generated in the metal material layer 3X and the insulating layer 2 is small in the vicinity of the interface between the metal material layer 3X and the insulating layer 2. On the other hand, since the relative displacement of the insulating layer 2 and the substrate 1 is restricted, thermal stress is generated in the substrate 1 and the insulating layer 2 in the vicinity of the interface between the insulating layer 2 and the substrate 1. However, since the insulating layer 2 is a resin, it has a low elastic modulus and is displaced more than the substrate 1 that is an inorganic material. Therefore, the thermal stress generated in the substrate 1 and the insulating layer 2 is relieved mainly in the insulating layer 2, and the anode 3 is partially in the interface due to the thermal stress generated in the substrate 1 and the insulating layer 2. Interatomic bonds are not broken.

Thereafter, in the state where the heating in the firing step (S6) is finished and cooled, each layer contracts to its original state. At that time, the interatomic bond of the metal material layer 3X is not broken at the interface between the metal material layer 3X and the insulating layer 2, and no hole-like defect occurs in the thickness direction of the anode 3.
The above is considered to be the reason why defects in the anode surface are suppressed in the organic EL panel 100.

<Test 2>
Next, in order to confirm the effect of reducing the number of defects on the anode surface of the organic EL panel 100, a transition metal is formed between the insulating layer 2 and the anode 3 in the same configuration as the organic EL panel 100 and the organic EL panel 100. The test was performed using Comparative Example 2 provided with a connection layer. The configuration according to Comparative Example 2 including the connection layer made of a transition metal between the anode 3 is an example of the configuration of the organic EL element 10X that constitutes the conventional organic EL panel 100X described in Patent Document 1.

FIG. 13 is a schematic cross-sectional view illustrating a configuration of a substrate, an insulating layer, and an anode in an organic EL panel according to Comparative Example 2. The comparative example 2 has a configuration in which the connection layer 3Y made of tungsten (W) is provided on the surface of the insulating layer 2 in the same configuration as the organic EL panel 100, and the anode 3 is stacked on the connection layer 3Y. Other configurations are the same as those of the organic EL panel 100. The connection layer 3Y is formed by forming a connection layer constituent material (for example, tungsten) on the surface of the insulating layer 2 by a sputtering method or a vacuum evaporation method, and further, using the metal material layer 3X of the anode 3 formed thereon, a holographic method. Can be formed by patterning. The linear expansion coefficient of the connection layer 3Y was 4.3 × 10 ⁻⁶ / K, and the thickness of the connection layer 3Y was 20 nm to 40 nm. That is, the comparative example 2 has a configuration in which the connection layer 3Y made of a transition metal and a relatively small coefficient of thermal expansion is in direct surface contact with the anode 3 made of a metal and having a relatively large coefficient of thermal expansion.

  In Test 2, first, the thickness of the connection layer was changed from 0 nm to 40 nm, and the state of voids on the anode surface was compared. FIG. 14 is a photograph in plan view of the organic EL panel 100 and the anode of the organic EL panel according to Comparative Example 2 when the thickness of the connection layer is changed. The thickness of the anode 3 of the sample used for this test is 200 nm. As shown in FIG. 14, in Comparative Example 2, it was confirmed that in the samples b1 and b2 where the thickness of the connection layer was 20 nm and 40 nm, dot-like voids were generated on the anode almost entirely on the anode. On the other hand, in sample a1, which is the organic EL panel 100 according to the embodiment, it was not confirmed that voids were generated on the anode.

  FIG. 15 is a graph of experimental results showing the defect distribution of the anodes of the organic EL panel 100 and the organic EL panel according to Comparative Example 2 when the thickness of the connection layer is changed. In FIG. 15, the vertical axis represents the number of defects in 3 pixels (number of voids) observed with a microscope, and the horizontal axis represents the measurement position of the defect distribution of the anode of the panel. FIG. 16 is a schematic diagram showing measurement positions of the defect distribution of the anode of the organic EL panel in FIG. Sputtering conditions (chamber pressure) at the time of forming the anode 3 of the organic EL panel 100 used in the test and the sample of Comparative Example 2 were set to two levels of 0.3 Pa and 0.8 Pa. As shown in FIG. 15, in Comparative Example 2, approximately 20 or more defects were counted at each measurement position in samples b1 and b2 in which the thickness of the connection layer was 20 nm and 40 nm. On the other hand, in the sample a1 which is the organic EL panel 100, defects are not generally counted at each measurement position.

  FIG. 17 is a photograph in plan view of the organic EL panel 100 and the anode of the organic EL panel according to Comparative Example 2 when the thickness of the anode is changed. The thickness of the anode 3 of the sample used for this test is 100 nm and 200 nm, and the thickness of the connection layer 3Y is 40 nm. As shown in FIG. 15, in Comparative Example 2, it was confirmed that in the samples b1 and b2 where the thickness of the anode 3 was 100 nm and 200 nm, dot-like voids were generated almost entirely on the anode on the anode. On the other hand, in sample a1, which is the organic EL panel 100 according to the embodiment, it was not confirmed that voids were generated on the anode.

  FIG. 18 is a graph of experimental results showing the number of defects in the anodes of the organic EL panel 100 and the organic EL panel according to Comparative Example 2 when the thickness of the anode is changed, and (a) shows the organic EL panel 100 (b ) Is the result of Comparative Example 2. The thickness of the connection layer 3Y of the sample used for this test is 40 nm. As shown in FIG. 18 (b), in Comparative Example 2, it was confirmed that the number of defects significantly increased as the thickness of the anode 3 decreased in the range where the thickness of the anode 3 was 280 nm or less. On the other hand, as shown in FIG. 18A, in the organic EL panel 100, the number of defects is as small as about 20 to 30 regardless of the thickness of the anode 3, and the increase in the number of defects accompanying the decrease in the thickness of the anode 3 is It was not confirmed. From this, it can be seen that the number of defects in the organic EL panel 100 is reduced more in the range where the thickness of the anode 3 is 280 nm or less in comparison with Comparative Example 2. That is, the configuration in which the insulating layer 2 and the anode 3 are in direct contact with each other is a range in which the thickness of the anode 3 is 280 nm or less compared to the configuration in which the connection layer made of a transition metal is provided between the insulating layer 2 and the anode 3. It can be seen that this is effective in reducing the number of defects.

<Reason for generating defects on anode surface in Comparative Example 2>
The reason why the organic EL panel 100 has resulted in a smaller number of defects on the anode surface compared to Comparative Example 2 is as follows.
As described above, the linear expansion coefficient of the connection layer 3Y made of a transition metal in direct contact with the anode 3 is 4.3 × 10 ⁻⁶ /, whereas the linear expansion coefficient of the anode 3 made of metal is about 24 × 10 6. ^-6 / K is relatively large. Further, in Comparative Example 1, the linear expansion coefficient of the substrate 1 that is in direct contact with the anode 3 is substantially equal to 3.9 to 4.5 × 10 ⁻⁶ / K. Therefore, it is considered that the anode 3 in Comparative Example 2 exhibits the same behavior as in Comparative Example 1.

  That is, in the heating state in the firing step (S6), the amount of thermal strain of the metal material layer 3X calculated from the heating temperature is relatively large with respect to the value of the connection layer 3Y. However, as described above, in Comparative Example 2, since the connection layer 3Y and the anode 3 (metal material layer 3X) are in direct surface contact, the relative displacement is constrained to each other. Therefore, thermal stress is generated in the connection layer 3Y and the anode 3 in the vicinity of the interface. Then, during the heating in the firing step (S6), the interatomic bond of the anode 3 is broken at a part of the interface in the connection layer 3Y and the anode 3 due to thermal stress. Thereafter, in the state where the heating in the firing step (S6) is finished and cooled, the connection layer 3Y and the anode 3 contract each other as in the case of the comparative example 1 described above. At that time, a hole-like defect may occur in the thickness direction of the anode 3 at a location where the interatomic bond of the anode 3 is cut at the interface between the connection layer 3Y and the anode 3.

The above is considered to be the reason why defects (voids) on the anode surface occurred in Comparative Example 2 as in Comparative Example 1.
4.2 Relationship between anode thickness and light emission efficiency <Test 3>
In order to confirm the effect of improving the light emission efficiency of the organic EL panel 100 according to the embodiment, the following effect confirmation test was performed. In the test, in the organic EL panel 100 according to the embodiment, the anode thickness was changed from 100 nm to 400 nm, and the light emission efficiency of the organic EL panel 100 was measured. In the measurement, a voltage that makes the anode 3 a positive potential was applied between the anode 3 and the cathode 10 to flow a predetermined current, and the illuminance (candela) of the light emitted from the sealing layer 11 was measured.

  FIG. 19 is a graph of experimental results showing the relationship between the thickness of the anode and the light emission efficiency of the organic EL panel 100 and the organic EL panel according to Comparative Example 2, and (a) is an organic EL element of a red sub-pixel. The light emission efficiency from 20c, (b) shows the light emission efficiency from the organic EL element 20b of a green subpixel, and (c) shows the light emission efficiency from the organic EL element 20a of a blue subpixel. As shown in FIG. 19, in the organic EL panel 100, the light emission efficiency is improved as the thickness of the anode 3 is decreased, and the inclination of the emission efficiency due to the decrease in the thickness of the anode 3 is within a range where the thickness of the anode 3 is less than 200 nm. Increase was confirmed. Thereby, in the organic EL panel 100, it turns out that the radiation | emission efficiency improves further in the range whose thickness of the anode 3 is less than 200 nm.

5. Summary As described above, in the organic EL panel 100 according to the present embodiment, the substrate 1 mainly containing an inorganic material, the insulating layer 2 mainly containing a resin, aluminum, and aluminum containing nickel or cobalt. An organic light emitting layer 8 including at least a first electrode layer 3 containing an alloy and having a thickness of 50 nm or more and less than 200 nm, a hole injection layer 5 made of a transition metal oxide, and a light emitting layer for receiving carriers injected from the first electrode. And a second electrode layer 10 having a polarity different from that of the first electrode layer 3 in this order, and at least a part of the surface of the first electrode layer 3 on the metal oxide layer side is free of nickel or cobalt. The thermal expansion coefficient of the insulating layer 2 is in contact with the injection layer 5 and is 8 to 13 times the thermal expansion coefficient of the substrate 1. That is, in the organic EL panel 100, between the substrate 1, the first electrode layer 3, and the insulating layer 2 between the substrate 1 having the smallest thermal expansion coefficient and the first electrode layer 3 having an intermediate thermal expansion coefficient. Further, it is possible to adopt a configuration in which the insulating layer 2 having the largest coefficient of thermal expansion is interposed. This suppresses the generation of defects (voids) generated on the surface of the first electrode due to the thermal stress associated with the heating and firing of the metal material layer for forming the first electrode layer 3, and the defects generated on the surface of the first electrode And the manufacturing quality of the organic EL panel can be improved. Moreover, the emission efficiency of the organic EL panel 100 can be improved by setting the thickness of the first electrode layer 3 to 50 nm or more and less than 200 nm.

  In another embodiment, the insulating layer 2 and the first electrode layer 3 may be in direct surface contact. As a result, the emission efficiency of the organic EL panel 100 is increased, and the connection layer 3Y made of a transition metal is provided between the first electrode layer 3 and the first electrode layer 3 in the thickness range where the emission efficiency of the organic EL panel 100 is high. The generation of voids on the surface of the anode 3 can be further suppressed as compared with the case where the provided structure is adopted.

  In another aspect, an aluminum oxide layer may be formed on the surface of the first electrode layer 3 on the hole injection layer 5 side with nickel or cobalt deposited at least partially. Good. In another aspect, the first electrode layer 3 may be formed by depositing aluminum and an aluminum nickel alloy or aluminum cobalt alloy on the insulating layer 2 by sputtering and then firing. . This prevents the current between the first electrode layer 3 and the hole injection layer 5 from being blocked by covering the entire surface of the first electrode layer 3 on the hole injection layer 5 side with an oxide of aluminum as an insulator. The first electrode layer 3 and the hole injection layer 5 can be in contact with each other via nickel or cobalt. As a result, the first electrode layer 3 and the hole injection layer 5 are electrically connected, and good carrier movement in the organic light emitting layer 8 can be realized.

≪Modification≫
In the embodiment, the organic EL panel 100 according to one embodiment of the present invention has been described. However, the present invention is not limited to the above embodiment except for essential characteristic components. For example, it is realized by arbitrarily combining the components and functions in each embodiment without departing from the scope of the present invention, or the form obtained by subjecting each embodiment to various modifications conceived by those skilled in the art. Forms are also included in the present invention. Below, the modification of the organic electroluminescent panel 100 is demonstrated as an example of such a form.

Although the top emission type organic EL panel has been described in the above embodiment, the present disclosure is not limited to this and may be a bottom emission type. In this case, it should be noted that the first electrode (anode) is made of a transparent material.
In the above embodiment, the firing step of the metal material layer 3X is performed after the metal oxide film 5X is formed. However, this is not essential, and the firing step may be performed at least after the formation of the transparent conductive film 4X. . Even in this method, the presence of the transparent conductive film 4X on the metal material layer 3X can prevent the generation of bubbles between the insulating layer 2 and the metal material layer 3X.

In the above-described embodiment, the configuration in which the hole transport layer, the electron injection layer, and the like are provided is illustrated, but these layers may be omitted as appropriate.
In the above embodiment, the light emitting layer is formed using a wet film forming process such as a printing method, a spin coating method, and an ink jet method, but the present invention is not limited to this. For example, a dry film forming process such as a vacuum evaporation method, an electron beam evaporation method, a sputtering method, a reactive sputtering method, an ion plating method, or a vapor deposition method can be used.

  Moreover, in the said embodiment, although the organic electroluminescent panel 100 was an active matrix type structure, this invention is not limited to this, For example, a passive matrix type structure may be sufficient. Specifically, a plurality of linear electrodes parallel to the extending direction of the bank and a plurality of linear electrodes orthogonal to the extending direction of the bank may be arranged in parallel so as to sandwich the light emitting layer. At this time, if a linear electrode orthogonal to the bank extending direction is the lower side, a plurality of lower electrodes are arranged in the bank extending direction at intervals in each gap. It becomes. In that case, it is possible to appropriately change each configuration. In the first embodiment, the substrate 1 has the TFT layer. However, as can be seen from the passive matrix type example, the substrate 1 is not limited to the configuration having the TFT layer.

  The display device using the organic EL panel according to the present invention can be widely used in various electronic apparatuses having a display panel such as a television set, a personal computer, a mobile phone, or the like.

1 substrate 2 insulating layer 3X metal material layer 3 anode 4X transparent conductive film 4 transparent electrode 5X transition metal oxide film 5 hole injection layer 6 bank 7 hole transport layer 8 organic light emitting layer 9 electron injection layer 10 cathode 11 sealing layer 20a, 20b, 20c Organic EL element 100 Organic EL panel

Claims (11)

A substrate mainly composed of an inorganic material;
An insulating layer mainly composed of a resin;
A first electrode layer comprising aluminum and an aluminum alloy containing nickel or cobalt, and having a thickness of 50 nm or more and less than 200 nm;
A hole injection layer made of a transition metal oxide;
An organic light emitting layer including at least a light emitting layer for receiving carriers injected from the first electrode;
A second electrode layer having a polarity different from that of the first electrode is provided in a state of being laminated in that order,
On the surface of the first electrode layer on the metal oxide layer side, nickel or cobalt is at least partially in contact with the hole injection layer,
The organic EL panel, wherein the thermal expansion coefficient of the insulating layer is 8 to 13 times the thermal expansion coefficient of the substrate. The organic EL panel according to claim 1, wherein the insulating layer and the first electrode layer are in direct surface contact. The organic EL panel according to claim 1, wherein a coefficient of thermal expansion of the material constituting the insulating layer is 30 × 10 ⁻⁶ / K or more and 60 × 10 ⁻⁶ / K or less. The organic EL panel according to claim 1, wherein a coefficient of thermal expansion of a substance constituting the substrate is 3.9 × 10 ⁻⁶ / K or more and 4.5 × 10 ⁻⁶ / K or less. The organic EL panel according to claim 1, wherein the material constituting the first electrode has a coefficient of thermal expansion of 2.0 × 10 ⁻⁶ / K or more and 2.8 × 10 ⁻⁶ / K or less. The organic EL panel according to claim 1, wherein the insulating layer has a thickness of 3000 nm to 5000 nm. The organic EL panel according to claim 1, wherein the resin is one or more resins selected from the group consisting of polyamide, polyimide, and acrylic resin. 2. The organic EL panel according to claim 1, wherein an oxide layer of aluminum is formed on a surface of the first electrode layer on the hole injection layer side with nickel or cobalt deposited at least partially. The organic EL panel according to claim 8, wherein the nickel or cobalt is present in an island shape in the aluminum metal oxide layer on the surface of the first electrode layer on the hole injection layer side. The first electrode layer constitutes an anode;
The second electrode layer constitutes a cathode;
The organic EL panel according to claim 1, wherein the nickel or cobalt or an oxide formed by the nickel or cobalt has a hole injection property of injecting holes as carriers. 2. The organic EL panel according to claim 1, wherein the first electrode layer is formed by depositing aluminum and an aluminum nickel alloy or an aluminum cobalt alloy on the insulating layer by sputtering and then firing.