CN115804246A

CN115804246A - Organic EL display device and method for manufacturing the same

Info

Publication number: CN115804246A
Application number: CN202180048825.9A
Authority: CN
Inventors: 新井猛; 三好一登
Original assignee: Toray Industries Inc
Current assignee: Toray Industries Inc
Priority date: 2020-07-31
Filing date: 2021-07-29
Publication date: 2023-03-14
Also published as: JPWO2022025173A1; WO2022025173A1; KR20230043787A

Abstract

The invention provides an organic EL display device and a manufacturing method thereof, wherein the organic EL display device including an auxiliary electrode is manufactured by a simple method, and the number of defects of a transparent electrode can be reduced and the sheet resistance can be reduced. One embodiment of the organic EL display device according to the present invention for achieving the above object is an organic EL display device including a substrate, and a reflective electrode, an insulating layer, an auxiliary electrode, an organic EL layer, and a transparent electrode on the substrate, wherein the insulating layer includes the auxiliary electrode, the organic EL layer, and the transparent electrode in this order, the organic EL layer includes one or more layers selected from the group consisting of a hole transport layer, a light emitting layer, and an electron transport layer, and a maximum height (Rz) of surface roughness of the auxiliary electrode on a side in contact with the organic EL layer is 30nm to 500 nm.

Description

Organic EL display device and method for manufacturing the same

Technical Field

The invention relates to an organic EL display device and a method of manufacturing the same

Background

Organic EL display devices are receiving attention as next-generation flat panel displays. The organic EL means electroluminescence of an organic EL layer containing an organic compound provided between 2 electrodes. Further, a display device using an organic EL light emitting element is an organic EL display device. Since a self-luminous organic EL display device can realize image display with a wide viewing angle, high-speed response, and high contrast, and can further realize thinning, weight reduction, and flexibility, research and development thereof have been actively carried out in recent years.

Organic EL display devices can be classified into a bottom emission type in which light is extracted on the substrate side and a top emission type in which light is extracted on the opposite side of the substrate according to the light extraction type. Compared with a display device using a bottom emission method, the top emission method can increase the area ratio of display pixels, and a display device with higher light emission efficiency can be realized. Among these, in a general active-drive top-emission organic EL display device including a TFT (thin film transistor), a structure is often adopted in which an electrode on the substrate side is connected to the TFT in an island shape, and a transparent electrode is provided on the opposite side of the substrate as a common layer. Since the organic EL display device is required to efficiently extract light emission from the organic EL layer, various studies have been made on a transparent electrode used in a top emission type organic EL display device. Among them, a transparent conductive film having a higher sheet resistance (sheet resistance) than a metal film is generally used, but many problems still remain in view of compatibility between transparency and electrical characteristics, necessity of film formation without damaging an organic EL layer, and the like. Therefore, a method using an auxiliary electrode is also proposed in order to reduce the resistance of the transparent electrode.

Among these auxiliary electrodes, there is also one in which a region on an insulating layer, which is a pixel division layer not affecting light emission, is used, and a method of connecting an auxiliary electrode and a transparent electrode by forming the auxiliary electrode into an overhang structure (for example, see patent document 1) and a method of connecting electrodes to each other by forming the transparent electrode into an island shape (for example, see patent document 2) have been proposed.

Documents of the prior art

Patent document

Patent document 1: japanese unexamined patent publication No. 2001-230086

Patent document 2: JP 2019-133921A

Disclosure of Invention

Problems to be solved by the invention

However, these auxiliary electrode solutions have problems of complicated structure and increased process load. Specifically, in patent document 1, in order to obtain the overhang structure, a process of forming the auxiliary electrode in 2 layers of the upper and lower portions, a process with high difficulty such as selection of a material of the auxiliary electrode having an etching rate limitation, and study of etching conditions for obtaining a desired shape are increased, and therefore, a reduction in yield and a significant increase in cost are caused.

In addition, patent document 2 requires patterning for forming the transparent electrode into an island shape, and has a disadvantage in a manufacturing process of a top emission type of transparent electrode that can be formed as a common layer over the entire surface of a display region in which display pixels are arranged.

Accordingly, an object of the present invention is to provide an organic EL display device and a method for manufacturing the same, which can reduce the number of defects in a transparent electrode and can reduce sheet resistance by manufacturing the organic EL display device including the formation of an auxiliary electrode by a simple method.

Means for solving the problems

A first embodiment of the organic EL display device of the present invention includes a substrate, and a reflective electrode, an insulating layer, an auxiliary electrode, an organic EL layer, and a transparent electrode on the substrate,

an auxiliary electrode, an organic EL layer and a transparent electrode are sequentially provided on the insulating layer,

the organic EL layer has at least one layer selected from the group consisting of a hole transport layer, a light emitting layer, and an electron transport layer,

the maximum height (Rz) of the surface roughness of the auxiliary electrode on the side in contact with the organic EL layer is 30nm to 500 nm.

In addition, a second embodiment of the organic EL display device of the present invention includes a substrate, an organic EL layer, and a transparent electrode in this order, and has a reflective electrode patterned on the substrate, an insulating layer formed in a gap of the reflective electrode, and an auxiliary electrode on the insulating layer, wherein the organic EL layer and the transparent electrode cover the entire surface of a display region, and the maximum height (Rz) of the surface roughness of the auxiliary electrode on the side in contact with the organic EL layer is 30nm to 500 nm.

Further, a method for manufacturing an organic EL display device according to the present invention includes: forming a patterned reflective electrode on a substrate; forming an insulating layer in the gap of the reflective electrode; forming an auxiliary electrode on the insulating layer; a step of roughening the auxiliary electrode; forming an organic EL layer covering the entire display region; and forming a transparent electrode covering the entire surface of the display region.

ADVANTAGEOUS EFFECTS OF INVENTION

The organic EL display device of the present invention is manufactured by a simple method including formation of an auxiliary electrode, and can reduce the number of defects of a transparent electrode and reduce sheet resistance.

Drawings

FIG. 1 is a schematic cross-sectional view of a top-emission organic EL display device.

Fig. 2 is a diagram showing the taper angle of the auxiliary electrode.

Fig. 3 is a schematic cross-sectional view of an active-drive top-emission organic EL display device.

FIG. 4 is a schematic view of a substrate used for measuring sheet resistance.

Detailed Description

Hereinafter, a mode for carrying out the present invention (hereinafter, referred to as "embodiment") will be described in detail. The present invention should not be limited to the embodiments described below.

< organic EL display device >

The organic EL display device of the present invention is a top emission type organic EL display device having a plurality of display pixels formed in a matrix. Further, according to the driving method, the driving method is roughly classified into: a passive driving type in which electrodes are divided into columns and rows and only display pixels held between the electrodes are caused to emit light; and an active drive type in which a plurality of TFTs are provided for each display pixel to perform switching, but the present invention is not particularly limited.

the organic EL layer has at least one layer selected from the group consisting of a hole transport layer, a light emitting layer and an electron transport layer,

The second embodiment of the organic EL display device of the present invention comprises a substrate, an organic EL layer, and a transparent electrode in this order, a reflection electrode patterned on the substrate, an insulating layer formed in a gap between the reflection electrode, and an auxiliary electrode on the insulating layer, wherein the organic EL layer and the transparent electrode cover the entire surface of a display region, and the maximum height (Rz) of the surface roughness of the auxiliary electrode on the side in contact with the organic EL layer is from 30nm to 500 nm. In the present invention, the display region refers to a region in which display pixels for display are arranged.

Fig. 1 is a schematic cross-sectional view of a top emission type organic EL display device as an example of the organic EL display device of the present invention. The top emission type organic EL display device of fig. 1 has a reflective electrode 2 on a substrate 1. The substrate 1 comprises a base material 13. The reflective electrode 2 has an insulating layer 3 in a gap therebetween, and an auxiliary electrode 4 is provided on the insulating layer 3. Above the auxiliary electrode 4, there are an organic EL layer 5 and a transparent electrode 6. Since the organic EL layer 5 is sandwiched between the reflective electrode 2 and the transparent electrode 6, light emission from the organic EL layer 5 is extracted from the opposite surface of the substrate.

< substrate >

In the organic EL display device of the present invention, the substrate may be composed of only a substrate described later, or wirings, TFTs, and the like may be provided on the substrate.

The wiring is often connected to an external device via an FPC (Flexible Printed Circuit) for driving. In addition to the TFT, a camera, sensors for reading ID and fingerprint, illuminance, and the like, a pattern antenna for communication or power supply, and the like may be provided. In the present invention, the wiring, the TFT, the sensors, the pattern antenna, and the planarization layer described later formed on the substrate are formed as part of the substrate, and the part of the substrate located below the reflective electrode (on the substrate side).

On such a substrate integrated with multiple functions, a planarization layer is preferably provided. By providing the planarization layer, the substrate can be planarized by covering the irregularities of the wiring, the TFT, and the like before the reflective electrode is formed. Then, an organic EL element in which a reflective electrode/an organic EL layer/a transparent electrode are combined is preferably provided on a planarization layer as a substrate. The organic EL element as a display element and the driving wiring are preferably connected through a contact hole formed in the planarization layer. In addition, an insulating layer needs to be provided in the gap of the reflective electrode mainly for the purpose of dividing the display pixels.

The range referred to as a display pixel is a range limited by a portion where the reflective electrode and the transparent electrode which are arranged to face each other intersect and overlap each other and an insulating layer located in a gap between the reflective electrodes. The shape of the display pixels may be rectangular or circular, for example, and may be easily changed depending on the shape of the insulating layer.

Further, full-color (full color) display can be performed by arranging organic EL elements having emission peak wavelengths in red, green, and blue regions, respectively, or by fabricating white organic EL elements over the entire surface and using them in combination with a separate color filter. In general, the peak wavelength of light in the red region is 560 to 700nm, the peak wavelength of light in the green region is 500 to 560nm, and the peak wavelength of light in the blue region is 420 to 500 nm.

Further, the organic EL element may have poor resistance to oxygen and moisture, and it is preferable to provide a sealing layer or a desiccant for ensuring light emission reliability on the display side of the device. In addition, depending on the environment and purpose of use, components such as a color filter for improving display quality, a polarizing layer for reflecting external light, and an ultraviolet absorbing layer for improving weather resistance reliability may be provided. When a touch panel is required according to the application, the touch sensor may be stacked and mounted. Particularly, when the touch sensor is provided, a glass cover or a hard coat film having excellent scratch resistance is preferably provided on the outermost surface side.

Fig. 3 is a schematic cross-sectional view of a general top-emission organic EL display device. The top emission type organic EL display device of fig. 3 includes a driving circuit 7 on a substrate 13. On which a planarization layer 8 is processed, holes for connection with the drive circuits 7 are provided. The reflective electrode 2 is formed on the substrate thus obtained, and is connected to the drive circuit 7 through a hole provided in advance. The reflective electrode 2 has an insulating layer 3 in a gap thereof, and an auxiliary electrode 4 on the insulating layer. Having thereon an organic EL layer 5 and a transparent electrode 6. Since the organic EL layer 5 is sandwiched between the reflective electrode 2 and the transparent electrode 6, light emission from the organic EL layer 5 is extracted from the opposite surface of the substrate. Further, a sealing layer 9, a polarizing layer 10, and an ultraviolet absorbing layer 11 are provided. The order of the sealing layer 9, the polarizing layer 10, and the ultraviolet absorbing layer 11 is not limited to this, and may be replaced or omitted as appropriate.

< substrate >

As the substrate, a substrate such as metal, glass, or a resin film which is preferable for supporting the display device and carrying in the subsequent step can be appropriately selected. In particular, in the case where light transmittance is required, glass or a resin film may be used.

As the glass, soda lime glass, alkali-free glass, or the like can be used. The thickness of the glass may be sufficient to ensure mechanical strength. As for the material of the glass, the less the ion eluted from the glass, the better, so the alkali-free glass is preferable, and SiO implemented glass may be used ₂ Etc. barrier coated soda lime glass.

As a material of the resin film, a material containing a resin film selected from polybenzoxazole, polyamideimide, polyimide, polyamide, and poly (p-xylene) is preferable in terms of excellent light transmittance. The substrate may contain these materials of the resin film alone or in combination.

For example, in the case of forming a substrate from polyimide, the substrate may be formed by applying a solution containing polyamic acid (containing polyamic acid partially imidized) or soluble polyimide as a polyimide precursor to a support substrate and firing the solution.

Further, since the organic EL element has low resistance to oxygen and moisture, a gas barrier layer can be provided as a suitable substrate. In particular, in the case of a resin film, a display device having high emission reliability can be obtained by laminating an inorganic thin film.

< reflective electrode >

The first embodiment of the organic EL display device of the present invention has a reflective electrode on a substrate.

In the second embodiment of the organic EL display device according to the present invention, the reflective electrode is patterned on the substrate. In the present invention, the reflective electrode means an electrode having a reflectance of 80% or more. In order to efficiently extract luminescence, the reflectance is preferably 90% or more. Here, the reflectance of the reflective electrode in the present invention refers to the reflectance at a wavelength of 550 nm. The reflectance of the reflective electrode can be measured by a spectrophotometer with respect to the electrode formed on the substrate.

As the reflective electrode, a material exhibiting high reflectance to visible light and low resistance is preferable over a certain thickness. Therefore, as an example of the material of the reflective electrode, a metal or an alloy containing Ag, al, cr, mo, or Ni as a main component is preferable. Further, ag or an Ag alloy containing Ag as a main component is more preferable as a material of the reflective electrode in terms of weather resistance and reflectance under a use environment, in addition to wet etching, cleaning, storage, and subsequent steps. An AgPdCu alloy, an AgTiCu alloy, an AgIn alloy, an AgZn alloy, an AgZnBi alloy, or the like containing Ag as a main component can be used.

Further, al or an Al alloy containing Al as a main component is also preferable as a material of the reflective electrode for top emission. Among them, an AlNi alloy, an AlCr alloy, an AlTi alloy, and an AlNd alloy are preferable. For example, an AlNi alloy containing 0.1 to 2 atomic% of Ni is preferable because it has a high reflectance equivalent to that of pure Al and can achieve a low contact resistance even when the AlNi alloy is directly connected to an oxide conductive material such as ITO or IZO. The main component in the present invention means a metal that is contained in the largest number of atoms in the object.

In addition, in order to have composite characteristics, it is also preferable that the reflective electrode has a multilayer structure. For example, it is also preferable that the substrate side has a base layer for improving adhesion and corrosion resistance, and the work function adjusting layer is laminated on the outermost layer on the organic EL layer side. By adjusting the work function difference with the organic EL layer at the interface on the organic EL layer side, an effect of promoting carrier injection for light emission can be provided. The work function adjusting layer may be selected from known materials, but ITO, IZO, AZO, GZO, ATO, WO, which have high transmittance and low resistivity, are preferable _X 、MoO _X And so on. Among these, ITO that can be used together with the base layer is particularly preferable.

The resistance of the reflective electrode is not limited as long as a sufficient current can be supplied for light emission of the light emitting element. From the viewpoint of power consumption of the light-emitting element, the resistance is preferably small. Specifically, the resistance of the reflective electrode is preferably 10 ohms or less, and more preferably 5 ohms or less as the sheet resistance. The lower limit is not particularly limited, and is usually about 1 ohm as the sheet resistance.

The thickness of the reflective electrode can be arbitrarily selected depending on characteristics such as reflectance and resistance, and is usually 100 to 1000nm.

The reflective electrode can be formed by a known method. For example, the film can be formed by a vacuum film formation method such as vapor deposition or sputtering, and patterned with a photosensitive resist.

< insulating layer >

The first embodiment of the organic EL display device of the present invention has an insulating layer on a substrate.

In the second embodiment of the organic EL display device of the present invention, the insulating layer is formed in the gap of the reflective electrode. By forming the insulating layer in the gap of the reflective electrode, the display pixel can be divided. That is, the insulating layer is patterned in the gap of the reflective electrode to define the exposed portion of the reflective electrode, and only the opening portion functions as a display pixel. In addition, the insulating layer covers the periphery of the island-shaped reflective electrode, thereby preventing short circuit at the edge of the reflective electrode and disconnection of the transparent electrode, and improving the reliability of the display device. In the second embodiment of the organic EL display device according to the present invention, the insulating layer may be formed in a region other than the gap of the reflective electrode as necessary.

The insulating layer is not limited to any of an organic insulating layer and an inorganic insulating layer, and is preferably a cured film containing a photosensitive resin composition in view of processability.

The photosensitive resin composition preferably contains (a) an alkali-soluble resin, (B) a sensitizer, and (C) an organic solvent, and may further contain (D) a coloring material. By combining (a) an alkali-soluble resin and (B) a photosensitizer as a photosensitive resin composition, patterning processing utilizing photosensitivity can be performed. Further, by containing (C) an organic solvent, a varnish state can be formed, and the coatability can be improved in some cases. Further, by adding (D) a coloring material to the photosensitive resin composition, the insulating layer can be blackened. The photosensitive resin composition may further contain other components.

The insulating layer can be formed by a known method. Among them, a wet coating method is preferable because a thin film can be uniformly formed on a large substrate. Examples of the wet coating method include spin coating, slit coating, dip coating, spray coating, and printing.

The thickness of the insulating layer is usually 0.3 μm to 10 μm, and is not particularly limited as long as it is sufficient to cover the irregularities of the reflective electrode. In addition, since the structure covering the transparent electrode is supported in the subsequent step and the strength of the display device is also affected, it is also effective to appropriately make the structure in a step shape or the like. In addition, the insulating layer must be patterned, and the residue in the removed portion may directly cause defects such as short circuits and black spots. Further, the edge of the insulating layer is preferably gently forward tapered because the transparent electrode is broken due to its shape.

< A) alkali-soluble resin >

The alkali-soluble in the present invention means: a solution obtained by dissolving a resin in gamma-butyrolactone was applied to a silicon wafer, prebaked at 120 ℃ for 4 minutes to form a prebaked film having a thickness of 10 [ mu ] m + -0.5 [ mu ] m, the prebaked film was immersed in a 2.38 mass% tetramethylammonium hydroxide aqueous solution at 23 + -1 ℃ for 1 minute, and then rinsed with pure water, and the dissolution rate determined from the decrease in film thickness at that time was 50 nm/minute or more.

From the viewpoint of improving heat resistance, the (a) alkali-soluble resin preferably has an aromatic carboxylic acid structure. In the present invention, the aromatic carboxylic acid structure refers to a carboxylic acid structure directly covalently bonded to an aromatic ring. When the heat resistance is improved, in the step of forming the auxiliary electrode on the insulating layer, troubles such as decomposition of the insulating layer and degassing from the insulating layer are less likely to occur. Specifically, when the auxiliary electrode is formed on the insulating layer by sputtering, for example, the degree of vacuum in the process is easily maintained sufficiently.

Examples of the material of the alkali-soluble resin (a) include polyamide resins, polyimide resins, polybenzoxazole resins, polysiloxane resins, acrylic resins, epoxy resins, cardo resins, and precursors of these resins. (A) The material of the alkali-soluble resin may be a mixture of two or more of these resins and precursors of these resins.

Among these resins, the photosensitive resin composition preferably contains a polyimide resin, a polyimide precursor, a polybenzoxazole resin and/or a polybenzoxazole precursor, from the viewpoint of satisfying both heat resistance and chemical resistance. When the chemical resistance is high, the film loss when the auxiliary electrode on the insulating layer is processed by wet etching is small, which is preferable. Since the film is reduced, there is no undercut structure at the end of the auxiliary electrode, and disconnection of the transparent electrode is not easily caused. Further, a polyimide precursor is particularly preferable because the amount of exhaust gas under high temperature conditions is small. Further, from the viewpoint of improving the alkali solubility, a polyimide precursor having an amic acid structure is more preferable.

< auxiliary electrode >

In the organic EL display device of the present invention, the auxiliary electrode is located on the insulating layer.

The auxiliary electrode is not particularly limited as long as it is a material having conductivity, but it is important that the surface roughness of the side in contact with the organic EL layer can be finally increased as described later. In the present invention, an Atomic Force Microscope (AFM) used for measuring the surface roughness is generally used to measure a substrate of an organic EL display device placed on a horizontal plane from vertically above. Therefore, in the present invention, the "surface roughness of the auxiliary electrode on the side in contact with the organic EL layer" refers to the surface roughness of a surface of the auxiliary electrode that can be measured by AFM, that is, a surface substantially parallel to the substrate.

In the organic EL display device of the present invention, the end portion of the auxiliary electrode is preferably a forward tapered shape. Here, the forward tapered shape refers to a state in which an angle formed by a tangent line at an interface between the insulating layer and the auxiliary electrode and a tangent line at 50% of the thickness of the auxiliary electrode at an end of the auxiliary electrode is less than 90 degrees.

The taper angle of the auxiliary electrode will be described with reference to fig. 2. In fig. 2, a substrate 1 has a reflective electrode 2 thereon. Here, the substrate 1 is composed of a base material 13. An insulating layer 3 is provided in the gap of the reflective electrode 2, and an auxiliary electrode 4 is provided on the insulating layer. An angle formed by a tangent to the interface between the insulating layer and the auxiliary electrode and a tangent to a 50% portion (point a) of the auxiliary electrode thickness at the end of the auxiliary electrode is defined as a taper angle (B).

The tapered shape can be adjusted according to the etching conditions, and can be confirmed by observing the cross section of the substrate.

Examples of the material for the auxiliary electrode include one metal selected from Al, au, cr, cu, ni, pt, sn, ti, zn, and the like, or an alloy containing two or more metals. Among them, the auxiliary electrode preferably contains one or more selected from the group consisting of Ag, al, cu, mo, and Ni, and more preferably the main component of the auxiliary electrode is at least one of Ag, al, cu, mo, and Ni. In view of workability, the main component of the auxiliary electrode is preferably Ag. By using Ag as a main component, a desired shape can be easily obtained, and finally, it is possible to effectively contribute to lowering the resistance of the transparent electrode.

In the organic EL display device of the present invention, the auxiliary electrode preferably includes a cured film of a resin composition containing conductive fine particles. By using an auxiliary electrode comprising a cured film of a resin composition containing conductive fine particles, the auxiliary electrode can be produced by a wet coating method in which coating is performed in an atmospheric pressure environment. Examples of the wet coating method include spin coating, slit coating, dip coating, spray coating, and printing. The definition, preferred form and the like of the conductive fine particles are as described later.

The resistance of the auxiliary electrode is not particularly limited as long as it is a sufficient characteristic for lowering the resistance of the transparent electrode. Specifically, the resistance of the auxiliary electrode is preferably 10 ohms or less, and more preferably 5 ohms or less as the sheet resistance. The lower limit is not particularly limited, and is usually about 1 ohm as the sheet resistance.

The thickness of the auxiliary electrode can be arbitrarily selected depending on characteristics such as reflectance and resistance value, and is usually about 100 to 1000nm.

In the organic EL display device of the present invention, the maximum height (Rz) of the surface roughness of the auxiliary electrode on the side in contact with the organic EL layer is 30nm to 500 nm. In the present specification, "the maximum height (Rz) in the surface roughness" may be simply referred to as "the maximum height (Rz)". If the maximum height (Rz) is less than 30nm, the thickness of the surface of the auxiliary electrode is equal to or less than that of the organic EL layer, and therefore, when a transparent electrode is formed in a subsequent step, the transparent electrode and the auxiliary electrode cannot be connected. On the other hand, if the maximum height (Rz) is more than 500nm, it causes pinholes in the transparent electrode or causes defects in the sealing layer described later.

The protrusions having the maximum height (Rz) within the above range are preferably present at a frequency of 1 or more in 10 μm 9633; inclusive. The presence of 1 or more frequencies easily provides a sufficient effect in reducing the resistance of the transparent electrode. The maximum height (Rz) and the existence frequency of the protrusions can be confirmed by observing the surface of the auxiliary electrode with an Atomic Force Microscope (AFM) to obtain the maximum height (Rz). The measurement of the maximum height (Rz) of the protrusions may be performed after the step of roughening the auxiliary electrode described later, or may be performed after removing a member above the roughened surface of the auxiliary electrode such as the organic EL layer, the transparent electrode, the sealing layer, the polarizing layer, and the ultraviolet absorbing layer from the organic EL display device. After the upper member is removed, the organic EL layer may partially remain, but if the surface of the auxiliary electrode is further washed with a general organic solvent such as acetone or THF (tetrahydrofuran), the surface of the auxiliary electrode can be measured.

< organic EL layer >

In a first embodiment of the organic EL display device of the present invention, the organic EL layer includes one or more layers selected from the group consisting of a hole transport layer, a light emitting layer, and an electron transport layer on the insulating layer.

In a second embodiment of the organic EL display device of the present invention, the organic EL layer covers the entire surface of the display region. In the second embodiment of the organic EL display device of the present invention, an organic EL layer covering the entire display region is formed between the auxiliary electrode and the transparent electrode.

As described above, the organic EL display device of the present invention is characterized in that the auxiliary electrode has a large surface roughness, and therefore the auxiliary electrode and the transparent electrode can be electrically connected even through the organic EL layer.

The structure of the organic EL layer in the present invention is not particularly limited, and may be, for example, (1) a hole transport layer/a light-emitting layer, (2) a hole transport layer/a light-emitting layer/an electron transport layer, or (3) a light-emitting layer/an electron transport layer. The thickness of each layer is usually selected from 1 to 200nm in consideration of influences on the resistance value of each layer material and the extraction efficiency of EL light emission. The thickness of the organic EL layer on the auxiliary electrode is preferably 30nm to 500 nm. When the thickness of the organic EL layer on the auxiliary electrode is 30nm or more, defects of the transparent electrode due to the surface roughness of the auxiliary electrode are less likely to occur, and the reliability of the display device is further improved. On the other hand, if the thickness of the organic EL layer on the auxiliary electrode is 500nm or less, the auxiliary electrode and the transparent electrode are easily connected.

In the organic EL display device of the present invention, it is further preferable that the thickness of the organic EL layer on the auxiliary electrode is smaller than the maximum height (Rz) of the surface roughness of the auxiliary electrode. With this configuration, the auxiliary electrode and the transparent electrode can be more reliably connected.

< hole transport layer >

The hole transport layer is formed by, for example, a method of stacking or mixing one or two or more hole transport materials or a method of using a mixture of a hole transport material and a polymer binder. In addition, an inorganic salt such as iron (III) chloride may be added to the hole-transporting material to form a hole-transporting layer. The hole-transporting material is not particularly limited as long as it is a compound that can form a thin film necessary for manufacturing a light-emitting element, inject holes from an electrode serving as an anode, and transport holes.

Preferable examples of the hole-transporting material include triphenylamine derivatives such as 4,4' -bis (N- (3-methylphenyl) -N-phenylamino) biphenyl, 4' -bis (N- (1-naphthyl) -N-phenylamino) biphenyl, and 4,4',4 ″ -tris (3-methylphenyl (phenyl) amino) triphenylamine; biscarbazole derivatives such as bis (N-allylcarbazole) and bis (N-alkylcarbazole); a pyrazoline derivative; stilbene compounds; a hydrazone-based compound; heterocyclic compounds such as benzofuran derivatives, thiophene derivatives, oxadiazole derivatives, phthalocyanine derivatives, and porphyrin derivatives; polycarbonates having the above-mentioned monomers in side chains in the polymer system, styrene derivatives; polythiophene, polyaniline, polyfluorene, polyvinylcarbazole, polysilane, and the like.

< light-emitting layer >

The light-emitting layer is a layer in which a light-emitting material is excited by recombination energy generated by collision of holes and electrons to emit light. It is a major feature of an organic EL display device that various multicolor light emission can be performed by selecting a material constituting the light emitting layer. The light-emitting layer may be a single layer or a stack of multiple layers, and each layer is formed of a light-emitting material (host material or dopant material). Each light-emitting layer may be formed of only one of a host material (host material) and a dopant material (dopant material), or may be formed of a combination of one or more host materials and one or more dopant materials. That is, in each light-emitting layer, only the host material or the dopant material may emit light, or both the host material and the dopant material may emit light. From the viewpoint of efficiently utilizing electric energy and obtaining light emission with high color purity, the light-emitting layer is preferably formed of a combination of a host material and a dopant material. The dopant material may be contained in the bulk of the host material or may be contained in a portion of the host material.

From the viewpoint of suppressing the concentration quenching phenomenon, the content of the dopant material in the light-emitting layer is 30 parts by mass or less, and more preferably 20 parts by mass or less, with respect to 100 parts by mass of the host material.

The light-emitting layer can be formed by the following method: for example, a method of co-evaporating a host material and a dopant material; a method of mixing a host material and a doping material in advance and then performing evaporation; and so on.

Examples of the dopant material constituting the light-emitting material include condensed ring derivatives such as anthracene and pyrene; metal complex compounds such as tris (8-hydroxyquinoline) aluminum; bisstyryl derivatives such as bisstyrylanthracene derivatives and distyrylbenzene derivatives; tetraphenylbutadiene derivatives; a dibenzofuran derivative; a carbazole derivative; indolocarbazole derivatives; a polyphenylene vinylene derivative; and so on.

As a dopant material used when the light-emitting layer performs triplet emission (phosphorescence emission), a metal complex compound containing at least one metal selected from the group consisting of iridium (Ir), ruthenium (Ru), palladium (Pd), platinum (Pt), osmium (Os), and rhenium (Re) is preferable. The ligand constituting the metal complex compound may be appropriately selected depending on the desired emission color, the performance of the organic EL display device, and the relationship with the host compound. Among them, the ligand preferably has a nitrogen-containing aromatic heterocycle such as a phenylpyridine skeleton, a phenylquinoline skeleton, or a carbene skeleton. Specific examples of the metal complex compound include tris (2-phenylpyridyl) iridium complex, bis (2-phenylpyridyl) (acetylacetonate) iridium complex, and tetraethylporphyrin platinum complex. Two or more of them may be used.

Examples of the host material constituting the light-emitting material include naphthalene, anthracene, phenanthrene, pyrene, perylene, and perylene,

And compounds having a condensed aromatic ring such as tetracene, triphenylene, perylene, fluoranthene, fluorene, and indene. Two or more of them may be used.

As a host material used when the light-emitting layer performs triplet light emission (phosphorescence emission), a metal-chelated hydroxyquinoline (oxinoid) compound, a dibenzofuran derivative, a dibenzothiophene derivative, a carbazole derivative, an indolocarbazole derivative, a triazine derivative, a triphenylene derivative, or the like is preferably used. Among them, a compound having an anthracene skeleton or a pyrene skeleton is more preferable because it is easy to obtain high-efficiency light emission.

< Electron transport layer >

The electron transport layer is a layer that transports electrons injected from the cathode to the light emitting layer. In the electron transport layer, it is desired that the electron injection efficiency is high and the injected electrons are transported with good efficiency. Therefore, the electron transport layer is preferably the following: has high electron affinity and electron mobility, is excellent in stability, and is less likely to generate impurities which become traps (traps) during production and use. In particular, when the thickness of the electron transporting layer is large, a compound having a molecular weight of 400 or more is preferable because a compound having a low molecular weight is likely to cause crystallization and deterioration. In consideration of the fact that the electron transport layer mainly functions to efficiently prevent holes from the anode from flowing to the cathode side without recombining the holes when the transport of the holes and the electrons is balanced, the electron transport layer in the present invention is also included as a layer having the same meaning as the hole blocking layer capable of efficiently blocking the movement of the holes because the effect of improving the light emission efficiency is the same as the case of the electron transport layer made of a material having a high electron transport ability even if the electron transport layer is made of a material having a low electron transport ability. The electron transport layer may be a single layer or a plurality of layers.

Examples of the electron transporting material constituting the electron transporting layer include condensed polycyclic aromatic derivatives such as naphthalene and anthracene. Two or more of them may be used. Among these, compounds having a heteroaromatic ring structure containing an electron-accepting nitrogen are preferable from the viewpoint of further reducing the driving voltage and obtaining high-efficiency light emission.

The electron-accepting nitrogen herein means a nitrogen atom having multiple bonds between adjacent atoms. Since the nitrogen atom has a high electronegativity, the multiple bond has an electron accepting property. Therefore, the electron-accepting nitrogen-containing aromatic heterocycle has high electron affinity. The electron transport material having electron-accepting nitrogen can easily accept electrons from the cathode, and thus the driving voltage can be further reduced. In addition, the supply of electrons to the light-emitting layer increases, and the recombination probability increases, thereby improving the light-emitting efficiency.

Examples of the heteroaromatic ring containing an electron-accepting nitrogen include a triazine ring and a pyridine ring. As the compound having such a heteroaromatic ring structure, a triazole derivative such as N-naphthyl-2, 5-diphenyl-1, 3, 4-triazole, a bipyridine derivative such as 2, 5-bis (6 '- (2', 2 '-bipyridyl)) -1, 1-dimethyl-3, 4-diphenylthiaole, or a bipyridine derivative such as 1, 3-bis (4' - (2, 2':6' -terpyridyl)) benzene can be preferably used from the viewpoint of electron transport ability. Two or more of them may be used.

The electron-transporting material may be used alone, or two or more kinds of the electron-transporting materials may be used in combination, or one or more kinds of other electron-transporting materials may be used in combination with the electron-transporting material.

The electron transport layer may contain an electron donating compound. Here, the electron donating compound is a compound that facilitates electron injection from the cathode or the electron injection layer into the electron transport layer by improving the electron injection barrier, and further improves the conductivity of the electron transport layer.

Examples of the electron donating compound include an alkali metal, an inorganic salt of an alkali metal, a complex of an alkali metal and an organic substance, an alkaline earth metal, an inorganic salt of an alkaline earth metal, a complex of an alkaline earth metal and an organic substance, and the like.

The electron donating compound is preferably an inorganic salt or a complex with an organic substance, as compared with a simple metal, from the viewpoint of easy vapor deposition in vacuum and excellent handling, and more preferably a complex with an organic substance, from the viewpoint of easy handling in the atmosphere and easy adjustment of the addition concentration.

< transparent electrode >

The first embodiment of the organic EL display device of the present invention has a transparent electrode on an insulating layer.

In a second embodiment of the organic EL display device of the present invention, the transparent electrode covers the entire surface of the display region.

In the present invention, the transparent electrode means an electrode having a light transmittance of 30% or more at a wavelength of 550 nm. Here, the light transmittance in the present invention can be measured by a spectrophotometer with respect to an electrode formed on a transparent glass substrate.

Examples of the material for forming the transparent electrode in the present invention include transparent conductive oxides, metals, and the like. In the case of use as an anode, ITO, IZO, AZO, GZO, ATO, etc. are preferable, and in the case of use as a cathode, li, mg, ag, al, etc. are preferable.

However, it is difficult to make the transparent electrode thick regardless of the material used, due to the requirement of light transmittance, and the resistance value as an electrode increases. In general, when a transparent electrode is provided as a common layer over the entire surface of a display region, if the resistance value of the electrode is increased, not only power consumption but also display abnormality such as luminance unevenness occurs. In the present invention, since good electrical connection to the auxiliary electrode provided on the insulating layer can be ensured, the resistance of the transparent electrode can be reduced, and display abnormality can be avoided.

< Driving Circuit >

In the present invention, as described above, the wiring or the TFT as the driver circuit may be provided as a component included in the substrate.

In the case of an active-drive top emission type organic EL display device, patterned island-shaped reflective electrodes are often connected to TFTs formed in advance as a part of a substrate.

Examples of the semiconductor layer of the TFT include a-Si (amorphous silicon), p-Si (Polycrystalline silicon), microcrystalline silicon, an Oxide typified by In-Ga-Zn-O, and LTPO (Low Temperature Polycrystalline Oxide) In which p-Si is used In combination with an Oxide. TFTs using a-Si (a-Si TFTs) have low mobility as an index indicating the ease of electron movement, and can be manufactured on a large substrate with a relatively short manufacturing process, and thus can be widely used for small-to-large-sized displays. On the other hand, a TFT using p-Si (p-SiTFT) has high mobility, and a driver circuit and the like can be formed on a glass substrate. p-SiTFT is preferably used mainly for small and medium-sized displays because the manufacturing process is longer than that of a-SiTFT and the difficulty of manufacturing on a large substrate is high. In particular, p-Si in p-SiTFT can be formed by instantaneously melting and crystallizing by irradiating a laser beam with a-Si as a starting film. In addition, there is a doping step of implanting phosphorus and boron into Si, which is not used in the manufacturing step of a-Si tfts. In the p-SiTFT, the threshold of the TFT characteristics can also be controlled by doping an impurity into the Si film.

When TFTs are roughly classified from the structural aspect, they can be classified into a bottom gate type and a top gate type. The a-SiTFT is preferably a bottom gate type, and the p-SiTFT is preferably a top gate type. For example, in the case of a top gate type, the semiconductor layer is connected to the drain-side electrode and the source-side electrode, and the gate electrode is provided above the semiconductor layer. In the bottom gate type, the gate electrode is disposed in the lowermost layer, and a semiconductor layer/insulating film is provided in the upper layer, and a source electrode and a drain electrode are formed in the upper layer. The gate electrode may be connected to the source and drain electrodes by straight lines to form an inverted triangle, which is also referred to as an "inverted staggered structure".

The TFT is formed on a substrate by repeating a number of times the essential steps of forming a thin film, patterning, etching, and cleaning. As a method of forming the TFT, for example, a known method can be used.

< planarization layer >

The organic EL display device of the present invention preferably has a planarization layer. By providing the planarization layer, particularly in the case where a wiring or a TFT is provided as a substrate as in the active matrix type, the planarization layer can be planarized while covering the unevenness.

In the case of having the planarization layer, since the reflective electrode is provided on the planarization layer, it is preferable that the reflective electrode and the driving wiring in the organic EL display device of the present invention be connected through a contact hole formed in the planarization layer.

The planarization layer is not limited to any of an organic planarization layer and an inorganic planarization layer. From the viewpoint of processability, the planarizing layer is preferably a cured film comprising a photosensitive resin composition. The planarizing layer can be applied by a wet coating method such as spin coating, slit coating, dip coating, spray coating, or printing, for example, because a thin film can be uniformly formed on a large substrate.

The photosensitive resin composition preferably contains (a) an alkali-soluble resin, (B) a sensitizer, and (C) an organic solvent, and may further contain (D) a coloring material. By combining (a) an alkali-soluble resin and (B) a photosensitizer as a photosensitive resin composition, patterning processing utilizing photosensitivity can be performed. Further, by containing the (C) organic solvent, a varnish state can be formed, and the coatability may be improved. Further, by adding (D) a coloring material to the photosensitive resin composition, the planarization layer can be blackened. The photosensitive resin composition may further contain other components.

Examples of the material of the alkali-soluble resin (a) include polyamide resins, polyimide resins, polybenzoxazole resins, polysiloxane resins, acrylic resins, epoxy resins, cardo resins, and precursors of these resins. (A) The material of the alkali-soluble resin may be a mixture of two or more of these resins and precursors of these resins. In the case where coloring is required, the photosensitive resin composition preferably contains (D) a coloring material as appropriate from the viewpoint of light-shielding properties and reflection prevention.

The thickness of the planarizing layer is not particularly limited as long as it is sufficient to cover the irregularities.

< sealing layer >

In the organic EL display device of the present invention, it is preferable that the transparent electrode is formed and then sealed with a sealing layer. This is because the organic EL element has poor resistance to oxygen and moisture. In order to obtain a display device with high reliability of light emission, it is preferable to seal in an atmosphere containing as little oxygen and moisture as possible. The member used for the sealing layer is preferably selected to have high gas barrier properties. Specifically, the moisture permeability of the sealing layer is preferably 20g/m ² Day atm or less. Further, the oxygen permeability of the seal layer is preferably 20cc/m ² Day atm or less. The moisture permeability can be measured by a method in accordance with JIS K7129 (2019). The oxygen transmission rate can be measured by a method in accordance with JIS K7126 (2006). By suppressing the moisture permeability and the oxygen permeability of the sealing layer to the above levels, it is possible to prevent moisture and oxygen, which cause deterioration of light emission reliability, from entering the light-emitting element. As a material constituting the sealing layer, for example, glass, a resin film, a gas barrier film, or the like can be appropriately selected as in the case of the base material. An example of the gas barrier film is SiO ₂ (silicon oxide), siN (silicon nitride), siON (silicon oxynitride), and the like. Further, a layer made of a resin material such as an acrylic resin or a silicone resin may be provided on a layer such as glass, a resin film, or a gas barrier film, and the sealing layer may be formed in a multilayer structure. Since the organic EL display device of the present invention is of a top emission type, the sealing layer is preferably light-transmissive. Specifically, the light transmittance at a wavelength of 550nm is preferably 30% or more, more preferably 50% or more, and still more preferably 70% or more. Here, the light transmittance in the present invention can be measured by a spectrophotometer with respect to a sealing layer formed on a transparent glass substrate.

In addition, when it is necessary to bond the sealant layer, an adhesive having high gas barrier properties is preferably used as the adhesive used. Specifically, for example, it can be selected from two-part epoxy adhesives (XNR, nagase ChemteX), organic device sealing materials (MOISTURE CUT, MORESCO), and the like, which are generally known as adhesives having high gas barrier properties. Alternatively, the glass frit may be bonded by melting the glass frit with a laser, for example.

In addition, it is also effective to introduce a drying agent in the sealing step in consideration of moisture. The desiccant is not particularly limited as long as it has high moisture adsorption performance. Specific examples thereof include barium oxide and calcium oxide.

< polarizing layer >

The organic EL display device of the present invention preferably further has a polarizing layer. Specifically, the polarizing layer is formed by laminating a λ/4 retardation layer and a linearly polarizing layer, and suppresses reflection of light incident from the outside. For example, a film obtained by dyeing a polyvinyl alcohol film with iodine and uniaxially stretching the film is often used as the linear polarizing layer. The material constituting the λ/4 phase difference plate is not particularly limited, but a polyimide-based resin is preferable from the viewpoint of having high heat resistance.

< ultraviolet absorbing layer >

The organic EL display device of the present invention preferably further includes an ultraviolet absorbing layer. By providing the ultraviolet absorbing layer, weather resistance reliability can be improved. In particular, when the organic EL display device of the present invention is used outdoors, it is effective to have an ultraviolet absorbing layer in order to absorb ultraviolet rays contained in sunlight. The ultraviolet absorbing layer is preferably a layer that absorbs light having a wavelength of 320nm or less, more preferably a layer that absorbs light having a wavelength of 360nm or less, and still more preferably a layer that absorbs light having a wavelength of 420nm or less. However, since light having a wavelength of 420nm or more overlaps with the emission wavelength of blue for display, the ultraviolet absorbing layer preferably has a high transmittance in a region having a wavelength of 420nm or more.

The ultraviolet absorbing layer preferably contains a resin. Examples of the resin include polyimide resins, polyamide resins, polyamideimide resins, polycarbonate resins, polyester resins, polyethersulfone resins, polyarylate resins, polyolefin resins, polyethylene terephthalate resins, polymethyl methacrylate resins, polysulfone resins, polyethylene resins, polyvinyl chloride resins, alicyclic olefin polymer resins, acrylic polymer resins, and cellulose ester resins. The ultraviolet absorbing layer may contain two or more of the above resins. Among these resins, polyimide resins and polyamide resins are preferred because of their high heat resistance, chemical resistance and flexibility.

The ultraviolet absorbing layer may contain an ultraviolet absorber. Examples of the ultraviolet absorber include benzophenone compounds, oxybenzophenone compounds, benzotriazole compounds, salicylate compounds, acrylonitrile compounds, cyanoacrylate compounds, hindered amine compounds, triazine compounds, nickel complex salt compounds, ultrafine titanium oxide particles, metal complex salt compounds, and high-molecular ultraviolet absorbers. Examples of the polymer ultraviolet absorber include an ultraviolet absorber obtained by copolymerizing a reactive ultraviolet absorber RUVA-93 produced by Otsuka chemical Co., ltd. with an acrylic monomer. The ultraviolet absorbing layer may contain two or more of these ultraviolet absorbers. The ultraviolet absorber is preferably a benzotriazole compound or a benzophenone compound, and more preferably a benzotriazole compound, from the viewpoint of excellent transparency.

< method for producing organic EL display device >

The method for manufacturing an organic EL display device of the present invention comprises the following steps in order: forming a patterned reflective electrode on a substrate; forming an insulating layer in the gap of the reflective electrode; forming an auxiliary electrode on the insulating layer; a step of roughening the auxiliary electrode; forming an organic EL layer covering the entire surface of the display region; and forming a transparent electrode covering the entire surface of the display region.

An example of the method for manufacturing an organic EL display device according to the present invention will be described with reference to a case of manufacturing the organic EL display device shown in fig. 3.

First, a drive circuit is provided on a glass substrate. As examples of the step of providing the driver circuit, the gate electrode can be formed by a known method such as a "gate electrode forming step", a "gate insulating film forming step", an "Si film forming step", and a "source electrode and drain electrode forming step".

Next, a planarizing layer is formed by, for example, a slit coating method.

Then, a process for forming a contact hole for the purpose of connecting to the reflective electrode is performed. As this processing, for example, if the material used as the planarization layer is photosensitive, it is possible to cope with the processing by photolithography; if the resist material is not photosensitive, it can be handled by a conventional etching process using the resist material as a mask.

The method for manufacturing an organic EL device of the present invention includes a step of forming a patterned reflective electrode on a substrate. In this step, the reflective electrode is formed, and the reflective electrode is left in an island shape so as to correspond to the display pixel.

The method for manufacturing an organic EL device of the present invention includes a step of forming an insulating layer in a gap of a reflective electrode. Specific examples of the step include a step of applying a photosensitive resin over the entire surface and then forming an opening in the reflective electrode by photolithography.

The method for manufacturing an organic EL device of the present invention includes a step of forming an auxiliary electrode on an insulating layer.

The auxiliary electrode can be formed by a known method. For example, the film can be formed by a vacuum film formation method such as vapor deposition or sputtering, or by physical vapor deposition, and patterned with a photosensitive resist. In the case of vapor deposition, coarse particles called droplets generated from a solid evaporation source are generated, and the surface roughness can be increased. In the case of sputtering, DC sputtering, which is composed of only a positive bias, is preferable because the film is smoothed by an etching effect when a negative bias is present in addition to the positive bias. Further, by selecting the condition of the large positive bias, the surface roughness can be expected to be further increased. In particular, high-power DC sputtering is preferable because the film formation rate is high and the yield is high. Specifically, it is preferable to form the film under the condition of DC500W or more, preferably DC1000W or more.

In the method of manufacturing an organic EL display device according to the present invention, the step of forming the auxiliary electrode on the insulating layer is preferably a step of forming the auxiliary electrode by a coating method. Examples of the particles for the coating method include ink jet and printing. The auxiliary electrode can be formed by forming a film of the conductive resin composition by an application method, and drying and curing the film by heating.

As an example of the conductive resin composition, a thermosetting conductive resin composition containing a conductive powder and a thermosetting resin is given. Here, the conductive powder is a powder containing one or more selected from the group consisting of Ag, al, cu, mo, and Ni, and has an average particle diameter (D50) of 0.1 to 20 μm. The average particle diameter (D50) can be measured by a laser diffraction method. Specifically, a sample of 0.3g of the conductive powder was weighed into a 50ml beaker, 30ml of isopropyl alcohol was added, and the mixture was dispersed by treatment for 5 minutes with an ultrasonic cleaner (USM-1, manufactured by ASONE corporation), and the dispersion was measured with a Microtrac particle size distribution measuring apparatus (9320-HRAX-100, manufactured by Nikkiso K.K.).

Examples of the thermosetting conductive resin composition include: using copper or silver powder, or silver-coated copper powder in which the surface of copper powder (copper or copper alloy powder) is coated with silver, as conductive powder contained in the composition; a composition in which an epoxy resin and/or a blocked polyisocyanate compound is used as a thermosetting resin; and so on.

In addition, another example of the conductive resin composition includes a resin composition containing conductive fine particles. Here, the conductive fine particles mean fine particles containing one or more selected from the group consisting of Ag, al, cu, mo, and Ni, and the particle diameter of the fine particles is 10nm or more and less than 1000nm. By setting the particle diameter of the conductive fine particles to the above range, a fine pattern having desired conductivity can be easily formed. In the present invention, the particle diameter of the conductive fine particles is measured by a laser diffraction method. In the method for manufacturing an organic EL display device according to the present invention, the step of forming the auxiliary electrode by the coating method is preferably a step of forming the auxiliary electrode by coating a resin composition containing conductive fine particles.

The resin composition containing conductive fine particles is preferably a photosensitive resin composition. By using the photosensitive resin composition, the patterning process is easily simplified. In particular, conductive fine particles having a particle diameter of 50nm or less are preferably used for forming an ultrafine pattern of 5 μm or less.

In the method for manufacturing an organic EL display device of the present invention, the conductive fine particles preferably include surface-coated conductive fine particles. By performing the surface coating, even when the welding of the conductive fine particles is performed under a condition close to room temperature, the welding of the conductive fine particles can be prevented. As a method for coating the surface of the conductive fine particles, a gas phase reaction method and coating with an organic material in a liquid phase are generally used. As a specific example of the conductive fine particles surface-coated with an organic substance, silver fine particles surface-coated with an amine compound, and the like are known.

In the method for manufacturing an organic EL display device according to the present invention, the conductive fine particles more preferably include conductive fine particles whose surfaces are coated with a simple carbon substance and/or a carbon compound. By including the conductive fine particles, both the resolution of the fine pattern and the conductivity after the heat treatment can be satisfied. The method for producing the conductive fine particles surface-coated with the simple carbon and/or the carbon compound is preferably a vapor phase reaction method, and more preferably a thermal plasma method in view of high productivity. Examples of the method of generating thermal plasma include arc discharge, high-frequency plasma, and hybrid plasma. Among them, the high-frequency plasma is preferable in terms of less contamination of impurities from the electrodes.

When photolithography using a photosensitive resist is used to form a pattern, a resist layer is first provided on an auxiliary electrode, and then the resist layer is exposed and developed to form a resist pattern. Then, a portion of the auxiliary electrode not covered with the resist pattern is removed by etching. As an etching method, for example, wet etching can be used. In wet etching, in general, in order to completely remove a portion of the auxiliary electrode which is not covered with the resist pattern, an etching time is set to be longer than a time required for etching only the auxiliary electrode by its thickness, that is, so-called just etching (hereinafter, referred to as "just etching time"). In this way, when etching is performed for a longer time than the proper amount of etching time, not only the portion not covered with the resist pattern but also the portion covered with the resist pattern is partially removed by etching from the side with respect to the auxiliary electrode. In this case, it is considered that the portions covered with the resist pattern are removed more as they are farther from the resist pattern in the thickness direction, and as a result, the end portions of the obtained extraction pattern are inverted-tapered. In the case of the reverse taper, when the transparent electrode is formed in a subsequent step, the possibility of occurrence of disconnection tends to be slightly high. When a disconnection occurs, there is a possibility that a panel failure may occur due to an increase in sheet resistance and insulation.

Examples of the photosensitive resist include commercially available products such as AZ (Shipley), KAR (Kodak), FPPR (fuji chemical industry), and OFPR (tokyo chemical industry).

The method for manufacturing an organic EL display device of the present invention includes a step of roughening an auxiliary electrode. By performing the roughening treatment, the surface roughness of the auxiliary electrode can be increased.

The opportunity of roughening treatment is not particularly limited as long as it is before the film formation of the organic EL layer. For example, the roughening treatment may be performed together with an etching step for patterning the auxiliary electrode, or may be performed together with a cleaning step before the organic EL layer is formed. Among them, from the viewpoint of high productivity, it is preferable to perform the roughening treatment together with the cleaning step before the formation of the organic EL layer.

The roughening treatment may be performed by mechanical polishing using an abrasive material, shot blasting or wet blasting by blasting an abrasive material, plasma treatment, dry etching such as RIE, or the like, and is not particularly limited. In the case where the roughening treatment is performed together with the etching step for patterning, conditions for increasing the surface roughness may be appropriately selected by setting the selection of the etching solution and the treatment temperature in the case of the wet etching treatment, and setting the etching gas, the power, and the like in the case of the dry etching treatment. In some cases, dehydration treatment such as heating and pressure reduction may be combined. For the reason of suppressing moisture absorption to the substrate in this manner, a dry etching step is preferred, and among them, from the viewpoint of controllability of processing, roughening treatment is more preferably plasma treatment.

As a gas used for the plasma treatment, a general gas such as oxygen, nitrogen, hydrogen, or argon can be selected. Among these, oxygen is more preferably used because of easy handling, high etching effect, and effective increase in surface roughness.

In the method for manufacturing an organic EL display device according to the present invention, it is preferable that a step of performing heat treatment at 180 to 260 ℃ is provided before a step of forming an organic EL layer, which will be described later. By performing heat treatment to dehydrate the substrate, a highly reliable display device can be obtained. In addition, when the surface roughness of the insulating layer is increased by roughening treatment, reflow may be caused to smooth the surface. In this case, by adjusting the temperature of the heat treatment to be equivalent to the curing temperature of the insulating layer, only the surface of the insulating layer can be smoothed without affecting the surface roughness of the auxiliary electrode.

The method for manufacturing an organic EL display device according to the present invention may include a step of cleaning the substrate before the step of forming an organic EL layer, which will be described later. In general, since contamination of a reflective electrode surface in a pre-step such as photolithography is often left, it is effective to perform wet or dry cleaning. In the wet cleaning, an organic solvent, a surfactant, water, an acid solution, an alkali solution, or the like can be used, and the cleaning can be selected from immersion, ultrasonic cleaning, boiling cleaning, and the like. In the case of dry cleaning, the cleaning solution may be selected from glow discharge treatment, plasma discharge treatment, UV/ozone treatment, and the like. In the dry cleaning using an oxygen atmosphere, the oxidation of the reflective electrode can be promoted to adjust the work function in addition to removing contaminants. For example, oxygen defects present on the outermost surface of the reflective electrode can be oxidized by the generated radical species and ion species, thereby increasing the work function. By adjusting the work function of the reflective electrode, the efficiency of carrier injection from the reflective electrode into the adjacent organic EL layer is increased, and as a result, the characteristics of the display device, such as light emission efficiency and reliability, are easily improved.

The method for manufacturing an organic EL device of the present invention includes a step of forming an organic EL layer covering the entire surface of a display region. Each layer of the organic EL layer, such as the hole transport layer, the light emitting layer, and the electron transport layer, can be formed by a known method, for example, by a mask evaporation method or an ink jet method.

The mask vapor deposition method is a method of depositing an organic compound by vapor deposition using a vapor deposition mask to form a pattern, and for example, a method of depositing by vapor deposition by disposing a vapor deposition mask having a desired pattern as an opening on the vapor deposition source side of a substrate is mentioned. In order to obtain a highly accurate vapor deposition pattern, it is important to bring the vapor deposition mask and the substrate into close contact with each other with high flatness, and a technique of applying tension to the vapor deposition mask, a technique of bringing the vapor deposition mask and the substrate into close contact with each other with a magnet disposed on the back surface of the substrate, or the like is generally used.

Examples of the method for producing the vapor deposition mask include etching, mechanical polishing, sandblasting, sintering, laser processing, use of a photosensitive resin, electroforming, and the like, and when a fine pattern is required, etching and electroforming with excellent processing accuracy are preferably used.

Since the difficulty increases as the pattern becomes finer in the mask vapor deposition method and the ink jet method, it is required to use a minimum necessary for, for example, a light emitting layer which determines an emission color. In this case, for example, by using a hole transport layer, an electron transport layer, or the like in common for each color other than the light-emitting layer, film formation over the entire surface is allowed, and productivity of the display device is improved.

The method for manufacturing an organic EL display device of the present invention includes a step of forming a transparent electrode covering the entire display region. After the organic EL layer is formed, a transparent electrode is formed. As the formation method, a known method can be used, but a vacuum evaporation method is preferable because deterioration or damage of the organic El layer serving as a base can be easily avoided. In general, when a transparent electrode is provided as a common layer over the entire display region, if the resistance value of the electrode is large, not only is power consumption increased, but also display abnormalities such as luminance unevenness are likely to occur. In contrast, in the present invention, since the transparent electrode can be electrically connected to the auxiliary electrode provided on the insulating layer in a satisfactory manner, the resistance of the transparent electrode can be reduced, and display abnormalities can be avoided.

In the method of manufacturing the organic EL display device of fig. 3, after the step of forming the transparent electrode, a sealing layer, a polarizing layer, and an ultraviolet absorbing layer are sequentially formed in a stacked manner. The organic EL display device of fig. 3 is completed as described above.

Examples

The present invention will be described below with reference to examples and the like.

< measurement of auxiliary electrode film thickness, cone Observation, surface roughness >

The film thickness of the auxiliary electrode in each of the examples and comparative examples was measured from the level difference of the patterned portion using a surface roughness measuring machine (SURFCOM 1400D, precision manufactured by tokyo co., ltd.). In the case of the taper, a cross section obtained by cutting the substrate was observed with a scanning electron microscope (SEM, S-3000N, manufactured by Hitachi high-tech). In terms of surface roughness, the maximum height (Rz) was used in the observation results using an atomic force microscope (AFM, dimension Icon by Bruker). As observation conditions, RTESP-300 probe, tapping mode, scan size 10 μm \9633;, scan rate 1Hz, and sampling line number 256.

< sheet resistance of auxiliary electrode >

As for the sheet resistance of the auxiliary electrodes used in the examples and comparative examples, the resistance value between opposite sides was measured for an electrode having a film thickness of 500nm formed on a glass substrate (OA-10; manufactured by Nippon Denko Co., ltd.) of 5cm \9633;. For the measurement, a source meter (source meter) (Keithley Instruments Co., ltd., 2400) was used. The results are summarized in Table 1.

[ Table 1]

< thickness of organic EL layer >

The thickness of the organic EL layer in each of the examples and comparative examples was determined by the value indicated by the quartz oscillation film thickness monitor. The quartz oscillation type film thickness monitor was calibrated in advance by an atomic force microscope (AFM, dimension Icon, bruker).

< Observation of defects in transparent electrode >

In the observation of defects in the transparent electrodes in each of examples and comparative examples, the elements produced in each of examples and comparative examples described later were allowed to stand at room temperature of 23 ℃ and humidity of 45% for 24 hours. When corrosion was observed in the auxiliary electrode and the organic EL layer, it was judged that the transparent electrode had a defect.

< formation of auxiliary electrode, organic EL layer, and transparent electrode >

For the deposition of the auxiliary electrode in each of the examples and comparative examples, a sputtering apparatus (SH-450 manufactured by Ulvac) was used. The respective film formation conditions are shown in table 2.

[ Table 2]

In the coating of the silver-coated aluminum powder, a conductive resin composition prepared by using an aluminum powder having a silver coating amount of 20 mass% and an average particle diameter (D50) of 6 μm, an epoxy resin (jER 825, mitsubishi chemical corporation) and a curing agent (boron trifluoride monomethylamine) was used. As a production method, 90 parts by mass of the silver-coated aluminum powder, 9.5 parts by mass of the epoxy resin as the thermosetting component, and 0.5 part by mass of the curing agent were blended, and kneaded by a three-roll mill. Then, diethylene glycol butyl ether acetate was added as a solvent to adjust the viscosity to 100 pas (1 rpm). The viscosity of the conductive resin composition was measured with a DV-III viscometer (Brookfield Co., ltd.). The viscosity at 1rpm rotation was measured at room temperature of 23 ℃ using CP-52 as a cone for the measurement. The average particle diameter (D50) was measured by a laser diffraction method. Specifically, a 0.3g sample of spherical powder was weighed into a 50ml beaker, 30ml of isopropyl alcohol was added, and the mixture was treated with an ultrasonic cleaner (USM-1, manufactured by ASONE corporation) for 5 minutes to disperse the mixture, and the average particle diameter (D50) was measured using a Microtrac particle size distribution measuring apparatus (Microtrac particle size distribution measuring apparatus 9320-HRAX-100, manufactured by nippon corporation). The conductive resin composition thus obtained was slit-coated on a substrate, and the substrate was heated in a hot air dryer at 180 ℃ for 60 minutes to be cured.

In addition, in the coating of the silver fine particles, 80g of silver fine particles NB-01 (manufactured by Nabond), 4.06g of dispersant DISPERBYK140 (manufactured by BYK-Chemie Japan K.K.) and 196.1g of solvent PGMEA were mixed by a homogenizer at 1200rpm for 30 minutes to obtain a mixed solution. The mixed solution was dispersed using a mill-type disperser filled with zirconia beads to obtain a silver particle dispersion. To 63.28g of this silver microparticle dispersion, 4.40g of a 40 mass% alkali-soluble resin (methyl (meth) ACRYLATE), 0.41g of a photopolymerization initiator (IRGACURE oxide 01 (manufactured by BASF)), and 1.30g of an acrylic monomer (LIGHT ACRYLATE PE-4A (manufactured by coor) were mixed, and 30.5g of a solvent (PGMEA) was added and stirred to prepare a photosensitive conductive resin composition. The photosensitive conductive resin composition thus obtained was coated on a substrate using a spin coater (1H-360S, MIKASA). The resultant was prebaked at 90 ℃ for 2 minutes using a hot plate (SCW-636, manufactured by SCREEN, japan), exposed to light, developed into a desired pattern, and cured at 250 ℃ for 30 minutes in air.

Further, a vapor deposition apparatus (VPC-1100, manufactured by Ulvac (R) Co.) was used for forming the organic EL layer and the transparent electrode.

< roughening treatment of auxiliary electrode >

The auxiliary electrode was roughened in each of the examples and comparative examples using a plasma processing apparatus (SPC-100B + H, manufactured by Hitachi Seisakusho Co., ltd.).

< preparation of photosensitive resin composition >

The photosensitive resin compositions R-1 to R-5 used in the examples and comparative examples were prepared as follows. Note that, as for the compounds to be used, abbreviated compounds are used, and the names are as follows.

4-MOP: 4-methoxyphenol

AIBN:2,2' -azobis (isobutyronitrile)

BAHF:2, 2-bis (3-amino-4-hydroxyphenyl) hexafluoropropane

DBA: dibenzylamine

DFA: n, N-dimethylformamide dimethyl acetal

GBL: gamma-butyrolactone

GMA: glycidyl methacrylate

MAA: methacrylic acid (MAA)

MAP: 3-aminophenol; meta-aminophenol

MeTMS: methyltrimethoxysilane

NMP: n-methyl-2-pyrrolidone

ODPA: bis (3, 4-dicarboxyphenyl) ether dianhydride; oxydiphthalic dianhydride

PGME: propylene glycol monomethyl ether

PGMEA: propylene glycol monomethyl ether acetate

PhTMS: phenyltrimethoxysilane

PI: polyimide, polyimide resin composition and polyimide resin composition

SiDA:1, 3-bis (3-aminopropyl) tetramethyldisiloxane

STR: styrene (meth) acrylic acid ester

TCDM: tricyclo [5.2.1.02,6] decan-8-yl methacrylate; dimethylol-tricyclodecane dimethacrylate (japanese: \\ 1247212513, \\ 12525401251251241241252312412412412412412412412512412487; \\ 1245912513\\ 12450631252412512512588

TMSSucA: 3-trimethoxysilylpropyl succinic anhydride

< Synthesis of polysiloxane solution (PS-1) >

A three-necked flask was charged with 28.95g (42.5 mol%) MeTMS, 49.57g (50 mol%) PhTMS and 74.01g PGMEA. Air was flowed into the flask at 0.05L/min, and the mixed solution was heated to 40 ℃ with stirring by an oil bath. While the mixed solution was further stirred, an aqueous phosphoric acid solution prepared by dissolving 0.442g of phosphoric acid in 27.71g of water was added dropwise over 10 minutes. After the completion of the dropwise addition, the mixture was stirred at 40 ℃ for 30 minutes to hydrolyze the silane compound. After completion of the hydrolysis, a solution prepared by dissolving 9.84g (7.5 mol%) of TMSSuca in 8.22g of PGMEA was added. Then, the bath temperature was set to 70 ℃ and stirred for 1 hour, and then, the bath temperature was subsequently raised to 115 ℃. After the start of the temperature rise, the internal temperature of the solution reached 100 ℃ after about 1 hour, from which the solution was stirred for 2 hours (internal temperature 100 to 110 ℃). The resin solution obtained by heating and stirring for 2 hours was cooled in an ice bath, and then the anion exchange resin and the cation exchange resin were added in an amount of 2 mass% relative to the resin solution, respectively, and stirred for 12 hours. After stirring, the anion-exchange resin and the cation-exchange resin were removed by filtration to obtain a polysiloxane solution (PS-1). The resulting polysiloxane had a Mw of 4,000 and a carboxylic acid equivalent weight of 910.

< Synthesis of acrylic resin solution (AC-1) >

A three-necked flask was charged with 0.821g (1 mol%) of AIBN and 29.29g of PGMEA. Then, 21.52g (50 mol%) of MAA, 22.03g (20 mol%) of TCDM, and 15.62g (30 mol%) of STR were added thereto, and the mixture was stirred at room temperature for a while, the inside of the flask was sufficiently replaced with nitrogen by bubbling, and then the mixture was stirred at 70 ℃ for 5 hours. Then, a solution prepared by dissolving 14.22g (20 mol%) of GMA, 0.676g (1 mol%) of DBA, and 0.186g (0.3 mol%) of 4-MOP in 59.47g of PGMEA was added to the obtained solution, and the mixture was stirred at 90 ℃ for 4 hours to obtain an acrylic resin solution (AC-1). The resulting acrylic resin had a Mw of 15,000, a carboxylic acid equivalent of 490 and a double bond equivalent of 730.

< Synthesis of polyimide precursor (PIP-1) >

In a three-necked flask, 31.02g (0.10 mol; 100mol% relative to the structural units derived from all carboxylic acids and derivatives thereof) of ODPA and 150g of NMP were weighed and dissolved under a stream of dry nitrogen. To this solution, a solution prepared by dissolving 25.64g (0.070 mol; 56.0mol% based on structural units derived from all amines and derivatives) of BAHF and 6.21g (0.0050 mol; 4.0mol% based on structural units derived from all amines and derivatives) of SiDA in 50g of NMP was added, and the mixture was stirred at 20 ℃ for 1 hour and then at 50 ℃ for 2 hours. Next, a solution prepared by dissolving 5.46g (0.050 mol; 40.0mol% based on the structural units derived from all the amines and derivatives) of MAP in 15g of NMP was added as a capping agent, and the mixture was stirred at 50 ℃ for 2 hours. Then, a solution prepared by dissolving 23.83g (0.20 mol) of DFA in 15g of NMP was added. After the addition, the mixture was stirred at 50 ℃ for 3 hours. After the reaction was completed, the reaction solution was cooled to room temperature, and then, the reaction solution was poured into 3L of water, followed by filtration to obtain a precipitated solid precipitate. The obtained solid was washed with water 3 times and then dried by a vacuum dryer at 80 ℃ for 24 hours to obtain a polyimide precursor (PIP-1).

< Synthesis of polyimide (PI-1) >

31.13g (0.085 mol; 77.3mol% relative to the structural units derived from all amines and derivatives thereof), 6.21g (0.0050 mol; 4.5mol% relative to the structural units derived from all amines and derivatives thereof), 2.18g (0.020 mol; 9.5mol% relative to the structural units derived from all amines and derivatives thereof) of MAP as a blocking agent, and 150.00g of NMP were weighed in a three-necked flask and dissolved under a stream of dry nitrogen. To this solution was added a solution prepared by dissolving 31.02g (0.10 mol; 100mol% based on the structural units derived from all carboxylic acids and derivatives) of ODPA in 50.00g of NMP, followed by stirring at 20 ℃ for 1 hour and then at 50 ℃ for 4 hours. Then, 15g of xylene was added, and the mixture was stirred at 150 ℃ for 5 hours while water was azeotroped with xylene. After the reaction, the reaction solution was poured into 3L of water, and the precipitated solid precipitate was obtained by filtration. The obtained solid was washed with water 3 times, and then dried with a vacuum drier at 80 ℃ for 24 hours to obtain polyimide (PI-1).

< Synthesis of polybenzoxazole precursor (PBO-1) >

41.3g (0.16 mol) of diphenyl ether-4, 4' -dicarboxylic acid was reacted with 43.2g (0.32 mol) of 1-hydroxy-1, 2, 3-benzotriazole under a dry nitrogen stream to obtain a mixture of dicarboxylic acid derivatives. The resulting mixture of dicarboxylic acid derivatives (0.16 mol) and BAHF (73.3 g, 0.20 mol) were dissolved in NMP (570 g) and reacted at 75 ℃ for 12 hours. Then, 13.1g (0.08 mol) of 5-norbornene-2, 3-dicarboxylic anhydride dissolved in 70g of NMP was added thereto, and the mixture was further stirred for 12 hours to terminate the reaction. After the reaction mixture was filtered, the reaction mixture was put into a solution of water/methanol =3/1 (volume ratio) to obtain a white precipitate. The precipitate was collected by filtration, washed with water 3 times, and then dried with a vacuum drier at 80 ℃ for 24 hours to obtain a target polybenzoxazole precursor (PBO-1).

< Synthesis of photosensitizer (B-1) >

21.22g (0.05 mol) of TrisP-PA (trade name, manufactured by chemical industries, ltd., japan) and 36.27g (0.135 mol) of 5-naphthoquinonediazide sulfonyl chloride were dissolved in 450g of 1, 4-dioxane under a stream of dry nitrogen gas, and the mixture was left at room temperature. 15.58g of triethylamine mixed with 50g of 1, 4-dioxane was added dropwise thereto so as not to reach 35 ℃ or higher in the system. After the dropwise addition, the mixture was stirred at 30 ℃ for 2 hours. The triethylamine salt was filtered and the filtrate was added to water. Then, the precipitated precipitate was collected by filtration. The precipitate was dried by a vacuum drier to obtain a quinone diazide compound represented by the following formula, i.e., a photosensitizer (B-1).

[ chemical formula 1]

< preparation of photosensitive resin composition R-1 >

PI-1 (10.0 g) as (A) an alkali-soluble resin having an acid group, B-1 (1.2 g) as (B) a sensitizer were added to PGME (32.0 g) and GBL (8.0 g) as (C) an organic solvent under a yellow lamp. Then, the resulting solution was used

Filtering with the filter of (3) to obtain a positive feelingA photosensitive resin composition R-1 which is a varnish of a light-sensitive resin composition.

< preparation of photosensitive resin composition R-2 >

PIP-1 (10.0 g) as (A) an alkali-soluble resin having an acid group, B-1 (1.2 g) as (B) a sensitizer were added to PGME (32.0 g) and GBL (8.0 g) as (C) an organic solvent under a yellow lamp. Then, the resulting solution was used

The photosensitive resin composition (2) was filtered through the filter to obtain a photosensitive resin composition R-2 as a varnish of a positive photosensitive resin composition.

< preparation of photosensitive resin composition R-3 >

PBO-1 (10.0 g) as (A) an alkali-soluble resin having an acid group and B-1 (1.2 g) as (B) a sensitizer were added to PGME (32.0 g) and GBL (8.0 g) as (C) an organic solvent under a yellow lamp. Then, the resulting solution was used

The photosensitive resin composition (4) was filtered through the filter to obtain a photosensitive resin composition R-3 as a varnish of a positive photosensitive resin composition.

< preparation of photosensitive resin composition R-4 >

PS-1 (10.0 g) as (A) an alkali-soluble resin having an acid group and B-1 (1.2 g) as (B) a sensitizer were added to PGME (32.0 g) and GBL (8.0 g) as (C) an organic solvent under a yellow lamp. Then, the resulting solution was used

The photosensitive resin composition (4) was filtered through the filter to obtain a photosensitive resin composition R-4 as a varnish of a positive photosensitive resin composition.

< preparation of photosensitive resin composition R-5 >

AC-1 (10.0 g) as (A) an alkali-soluble resin having an acid group and B-1 (1.2 g) as (B) a sensitizer were added to PGME (32.0 g) and GBL (8.0 g) as (C) an organic solvent under a yellow lamp. Then, the resulting solution was used

The photosensitive resin composition (4) was filtered through the filter to obtain a photosensitive resin composition R-5 as a varnish of a positive photosensitive resin composition.

< examples 1 to 19 and comparative examples 1 to 7>

The procedure for measuring the sheet resistance of the transparent electrodes in the examples and comparative examples will be described with reference to fig. 4a to F. The combinations of the insulating layer material and the auxiliary electrode material are shown in table 3. Comparative example 1 is an example without an auxiliary electrode.

[ Table 3]

First, agPdCu (100 nm) was deposited on a 5cm \9633; (A in FIG. 4) glass substrate 1 as a reflective electrode 2 by sputtering, and the reflective electrode was patterned by wet etching at 4.5X 5cm positions so that 2.5mm of each end portion remained (B in FIG. 4). Then, the insulating layer 3 of 4.6 × 5cm is formed so as to fill the gap of the reflective electrode 2 (C in fig. 4). At this time, the reflective electrodes 2 were formed so as to overlap the insulating layer 3 by 0.5mm for the purpose of preventing short-circuit and disconnection later. The auxiliary electrode 4 was formed to have a film thickness of 500nm over the entire surface of the substrate by the method shown in table 2. Ar is used as the sputtering gas, and the gas pressure at the start of film formation is 0.1Pa. Further, it was judged that the heat resistance of the insulating layer was insufficient when the pressure rise was observed during the film formation, and "degree of vacuum during sputtering" in table 2 is denoted by B. The case where the pressure rise during film formation was not observed is described as "a" as having sufficient heat resistance.

Then, a resist pattern was formed using a photosensitive resist, and wet etching was performed (conditions shown in table 4), thereby obtaining a substrate 1 on which an auxiliary electrode 4 of 4 × 5cm was formed (fig. 4D). In example 14, the auxiliary electrode material as the photosensitive conductive resin composition was patterned by photolithography. The results of confirming the presence or absence of undercut by cross-sectional observation are also shown in table 4. As a cause of the undercut, it is judged that the etching resistance of the insulating layer is insufficient.

[ Table 4]

Subsequently, roughening treatment by oxygen plasma is performed. The conditions and the maximum height after treatment (Rz) are shown in table 5. Comparative example 1 is an example in which the auxiliary electrode is not provided and the roughening treatment is not performed, and comparative examples 2 to 6 are examples in which the auxiliary electrode is provided and the roughening treatment is not performed.

[ Table 5]

Then, an organic compound (HT-1) represented by the following chemical formula was deposited over the entire surface of the substrate as an organic EL layer 5 with a thickness shown in table 6 (fig. 4E).

[ chemical formula 2]

Further, mg and Ag were mixed in a volume ratio of 9: 1A transparent electrode 6 (F in FIG. 4) was formed by vapor deposition of 20nm on the entire surface of a substrate 1. Finally, 500nm SiO was deposited in the same region as the insulating layer 3 ₂ As a sealing layer. The thickness of the deposited film was a value indicated by a quartz oscillation type film thickness monitor.

As shown in F of fig. 4, the resistance value between the opposite sides of the transparent electrode was measured as the sheet resistance using the tester 12, and the resistance value was 10 ohms or less and sufficiently small, and was judged as the characteristic (a) based on the electrical connection with the auxiliary electrode; a characteristic (B) when the resistance value exceeds 10 ohm and is below 30 ohm; a characteristic (C) when the resistance value exceeds 30 ohm and is less than 100 ohm; when the resistance value exceeded 100 ohms, it was judged as characteristic (D) and shown in the column of sheet resistance in table 6. In example 15, it was confirmed that the transparent electrode was partially disconnected at the end of the auxiliary electrode. The observation results of the defects after 24 hours of storage are also shown in "defects" in table 6. The transparent electrode had no defect A, partial defect B and total defect C.

[ Table 6]

Description of the reference numerals

1. Substrate

2. Reflective electrode

3. Insulating layer

4. Auxiliary electrode

5. Organic EL layer

6. Transparent electrode

7. Driving circuit

8. Planarization layer

9. Sealing layer

10. Polarizing layer

11. Ultraviolet absorbing layer

12. Testing device

13. Base material

Claims

1. An organic EL display device having a substrate, and a reflective electrode, an insulating layer, an auxiliary electrode, an organic EL layer and a transparent electrode on the substrate,

the organic EL layer has one or more layers selected from the group consisting of a hole transport layer, a light-emitting layer, and an electron transport layer,

2. An organic EL display device comprising a substrate, an organic EL layer and a transparent electrode in this order, a reflection electrode patterned on the substrate, an insulating layer formed in a gap between the reflection electrode, and an auxiliary electrode on the insulating layer, wherein the organic EL layer and the transparent electrode cover the entire display region, and the maximum height (Rz) of the surface roughness of the auxiliary electrode on the side in contact with the organic EL layer is 30nm to 500 nm.

3. The organic EL display device according to claim 1 or 2, wherein the thickness of the organic EL layer on the auxiliary electrode is 30nm or more and 500nm or less.

4. The organic EL display device according to any one of claims 1 to 3, wherein a thickness of the organic EL layer on the auxiliary electrode is smaller than a maximum height (Rz) of surface roughness of the auxiliary electrode.

5. The organic EL display device according to any one of claims 1 to 4, wherein an end portion of the auxiliary electrode has a forward tapered shape.

6. The organic EL display device according to any one of claims 1 to 5, wherein the auxiliary electrode contains one or more selected from the group consisting of Ag, al, cu, mo, and Ni.

7. The organic EL display device according to any one of claims 1 to 6, wherein the auxiliary electrode comprises a cured film of a resin composition containing conductive fine particles.

8. A method for manufacturing an organic EL display device, comprising the steps of: forming a patterned reflective electrode on a substrate; forming an insulating layer in the gap of the reflective electrode; forming an auxiliary electrode on the insulating layer; a step of roughening the auxiliary electrode; forming an organic EL layer covering the entire surface of the display region; and forming a transparent electrode covering the entire surface of the display region.

9. The method for manufacturing an organic EL display device according to claim 8, wherein the roughening treatment is a plasma treatment.

10. The method of manufacturing an organic EL display device according to claim 8 or 9, wherein the step of forming the auxiliary electrode on the insulating layer is a step of forming the auxiliary electrode by a coating method.

11. The method of manufacturing an organic EL display device according to claim 10, wherein the step of forming the auxiliary electrode by a coating method is a step of forming the auxiliary electrode by coating a resin composition containing conductive fine particles.