JP2009031761A - Organic el display device and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic EL display device having a TFT for driving the organic EL element disposed on the organic EL element and a method for producing the same, particularly, to provide an active-type organic EL display device having a high aperture ratio, excellent in definition, brightness and durability, and to provide a method for producing the same. <P>SOLUTION: The present invention provides the organic EL display device having the organic EL element and a thin film field-effect drive transistor formed on the organic EL element, wherein an electrically conductive etching protective layer 109 which is electrically connected to an upper electrode 34 is disposed between the upper electrode 34 and the thin film field-effect transistor, a protective insulating layer 106 is disposed between the electrically conductive etching protective layer 109 and the thin film field-effect transistor, and the source electrode 105a or the drain electrode 105b of the thin film field-effect transistor and the electrically conductive etching protective layer 109 are electrically connected through a contact hole 108 formed in the protective insulating layer 106, and a method for producing the same. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an organic EL display device in which a thin film field effect transistor for driving the organic EL element is disposed on the organic EL element, and a method for manufacturing the same. In particular, the present invention relates to an active organic EL display device having a high aperture ratio, high definition, high brightness, and long life and a method for manufacturing the same.

2. Description of the Related Art In recent years, flat and thin image display devices (Flat Panel Displays: FPD) have been put into practical use due to advances in liquid crystal and electroluminescence (EL) technologies. In particular, an organic electroluminescent device using a thin film material that emits light when excited by passing an electric current (hereinafter sometimes referred to as “organic EL device”) can emit light with high luminance at a low voltage. Device thinning, lightening, miniaturization, and power saving are expected in a wide range of fields including mobile phone displays, personal digital assistants (PDAs), computer displays, automobile information displays, TV monitors, or general lighting. ing.
These FPDs are active field-effect thin film transistors (hereinafter referred to as “Thin Film Transistor” or “TFT”) that use an amorphous silicon thin film or a polycrystalline silicon thin film provided on a glass substrate as an active layer. It is driven by a matrix circuit.

On the other hand, in order to achieve further high definition, high brightness, and long life of these active organic EL display devices, it is known that a top emission method capable of obtaining a high aperture ratio is advantageous. However, it is difficult to form a transparent conductive film such as ITO directly on the organic layer without damaging the organic EL element having the top emission structure. Therefore, a highly efficient and long-life element that is practically useful is manufactured. Is a difficult situation.
As another solution, it is disclosed that TFTs are formed so as to overlap each other on an organic EL element having a bottom emission structure (see, for example, Patent Document 1). However, the TFT used was composed of an organic semiconductor. An organic TFT made of an organic semiconductor can be formed on an organic EL element without damaging the organic EL element because it can be formed at a low temperature. However, the organic TFT has a problem in driving stability. In addition, there is a problem in reliability, for example, it is necessary to strictly seal against the outside air and humidity in order to improve storage stability. In addition, since the organic TFT has a low carrier mobility, the size (channel width) of the TFT becomes extremely large in order to increase the drive current. Therefore, it has been difficult to produce a high-definition and high-brightness organic EL display device.

On the other hand, the manufacture of a transistor using a silicon thin film has good stability and operational reliability. However, the manufacture requires a relatively high temperature thermal process. There was a problem because the EL element was damaged.
In recent years, active development of TFTs using semiconductor thin films of amorphous oxides that can be formed at low temperatures, such as In—Ga—Zn—O-based amorphous oxides, has been actively carried out (for example, see Patent Document 3, Patent Document 1). A TFT using an amorphous oxide semiconductor can be formed at room temperature and can be formed on a film, and thus has recently attracted attention as a material for an active layer of a film (flexible) TFT. In particular, Tokyo Institute of Technology, Hosono et al. Reported that a TFT using a-IGZO has a field effect mobility of about 10 cm ² / Vs even on a PEN substrate, which is higher than that of an a-Si TFT on glass. In particular, it has attracted attention as a film TFT (see, for example, Non-Patent Document 2).

However, in the case of using a TFT using the a-IGZO as a drive circuit of a display device, for ^example, the mobility of 1cm ² / Vs~10cm 2 / Vs, properties are insufficient, and high OFF current, ON / There is a problem that the OFF ratio is low. In particular, for use in a display device using an organic EL element, further improvement in mobility and improvement in the ON / OFF ratio are required.
JP 2005-242028 A JP 2006-12785 A JP 2006-165529 A IDW / AD'05, pages 845-846 (6, December, 2005) NATURE, Vol. 432 (November 25, 2004), pages 488-492

  Furthermore, in the case where a TFT is formed by being superimposed on an organic EL element having a bottom emission structure, in order to electrically connect the organic EL element and the TFT, an insulating protective film is disposed between the organic EL element and the TFT, A contact hole is opened in the insulating protective film at a location where electrical insulation is required and electrical bonding is required, and conduction is established through the contact hole. In order to make a contact hole in the insulating protective film, an etching method, a transfer method using a printing technique, an ink-jet method, a method of forming a shadow pattern with a mask and depositing an insulating layer are known.

  For example, an organic EL display device including a TFT using an organic semiconductor via an organic protective film such as parylene on an upper electrode of an organic EL element is disclosed. It has been proposed that the organic protective film is formed using a chemical vapor deposition method with the contact hole portion masked (see, for example, Patent Document 2). However, chemical vapor deposition by masking is difficult to form a high-definition pattern. Since a TFT using an organic semiconductor has a small driving current, it is difficult to form a high-definition pixel in the first place. Therefore, the TFT is merely a contact hole manufacturing means used in combination with such a TFT. It is not suitable as a contact hole forming means for a high-definition organic EL display device.

An etching method is preferable as a means for providing a contact hole with high definition. In particular, in producing a high-definition, high-brightness organic EL display device in which TFTs are formed by overlapping TFTs on a bottom emission organic EL element, contact hole formation by an etching method is a preferable means. A unique problem of forming TFTs on EL elements has been found. As the etching method, wet etching, dry etching, laser ablation, or the like is used, but there is a concern that any of the methods may damage the upper electrode of the organic EL element. For the upper electrode of the organic EL element, vacuum deposition by heat resistance heating is generally used with little damage to the organic layer. However, vacuum vapor deposition by heat resistance heating causes little damage during vapor deposition, but the resulting film is dense and contains many pinholes. Therefore, in the etching process for forming the contact hole of the insulating protective film, the etching material acts on the upper electrode through the pinhole and causes damage. When the damage further proceeds, the organic layer is also damaged, and the characteristics of the organic EL element are deteriorated.
Therefore, an etching method that does not damage the organic EL element including the upper electrode is desired.

  An object of the present invention is to provide an organic EL display device in which a TFT for driving the organic EL element is arranged on the organic EL element, and a manufacturing method thereof. In particular, it is an object of the present invention to provide an active organic EL display device having a high aperture ratio, high definition, high brightness, and long life and a method for manufacturing the same. In particular, by reducing damage to the organic EL element when forming a contact hole in the insulating protective film on the organic EL element, a high-definition, high-brightness, and long-life active organic EL display device and method for manufacturing the same Is to provide.

The above-described problems of the present invention have been solved by the following means.
<1> An organic EL element in which at least a lower electrode, an organic layer including at least a light emitting layer, and an upper electrode are sequentially formed on a substrate, and a TFT for driving the organic EL element formed on the organic EL element. An organic EL display device comprising a conductive etching protective film in electrical contact with the upper electrode between the upper electrode and the TFT, and protecting between the conductive etching protective film and the TFT An organic EL display device comprising an insulating film, wherein the TFT source or drain electrode and the conductive etching protective film are electrically connected through a contact hole provided in the protective insulating film.
<2> The contact hole is formed by etching with an etching material, and the etching rate of the conductive etching protective film is slower than the etching rate of the upper electrode with the etching material <1> The organic EL display device described in 1>.
<3> The contact hole is formed by etching with an etching material, and the etching rate of the conductive etching protective film is slower than the etching rate of the protective insulating film with the etching material. The organic EL display device according to <1> or <2>.
<4> The upper electrode is formed by a resistance heating vapor deposition method, and the conductive etching protective film is formed by a sputtering method, an ion plating method, or a CVD method. The organic EL display device according to any one of 3>.
<5> The organic EL display device according to any one of <1> to <4>, wherein the active layer of the TFT contains an oxide semiconductor, an organic semiconductor, or a carbon nanotube as a semiconductor material.
<6> The organic EL display device according to <5>, wherein the active layer of the TFT includes an oxide semiconductor.
<7> The organic EL display device according to <6>, wherein the oxide semiconductor is an amorphous oxide semiconductor.
<8> The organic EL display device according to any one of <1> to <7>, wherein the lower electrode is a light transmissive electrode.
<9> The organic EL display device according to <8>, wherein the upper electrode is a light reflective electrode.
<10> The organic EL display device according to any one of <1> to <98>, wherein the lower electrode is an anode and the upper electrode is a cathode.
<11> The organic EL display device according to <10>, wherein the TFT has an N-type polarity.
<12> Any one of <1> to <11>, wherein a resistance layer is electrically connected between the active layer and at least one of the source electrode and the drain electrode. The organic EL display device described.
<13> The resistance layer and the active layer are formed in layers, the active layer is in contact with the gate insulating film, and the resistance layer is in contact with at least one of the source electrode and the drain electrode. <12> The organic EL display device according to <12>.
<14> The organic EL display device according to <13>, wherein the resistance layer is thicker than the active layer.
<15> The organic EL display device according to any one of <12> to <14>, wherein electrical conductivity between the resistance layer and the active layer continuously changes.
<16> The organic EL display device according to any one of <12> to <15>, wherein the active layer and the resistance layer include an oxide semiconductor.
<17> The organic EL display device according to <16>, wherein the oxide semiconductor includes at least one selected from the group consisting of In, Ga, and Zn, or a composite oxide thereof.
<18> The oxide semiconductor contains In and Zn, and the composition ratio of Zn and In (represented by the ratio of Zn to In, Zn / In) of the resistance layer is larger than the composition ratio Zn / In of the active layer. <22> The organic EL display device according to <17>.
<19> The organic EL display device according to any one of <16> to <18>, wherein an oxygen concentration of the active layer is lower than an oxygen concentration of the resistance layer.
<20> The organic EL display device according to any one of <12> to <19>, wherein the electric conductivity of the active layer is 10 ⁻⁴ Scm ⁻¹ or more and less than 10 ² Scm ⁻¹ .
<21> The organic EL display device according to <20>, wherein the electric conductivity of the active layer is 10 ⁻¹ Scm ⁻¹ or more and less than 10 ² Scm ⁻¹ .
<22> The ratio of the electrical conductivity of the active layer to the electrical conductivity of the resistive layer (the electrical conductivity of the active layer / the electrical conductivity of the resistive layer) is from 10 ^{1 to} 10 ^10. The organic EL display device according to any one of <12> to <21>.
<23> The ratio of the electrical conductivity of the active layer to the electrical conductivity of the resistive layer (the electrical conductivity of the active layer / the electrical conductivity of the resistive layer) is 10 ² or more and 10 ⁸ or less. <22> The organic EL display device according to <22>.
<24> The organic EL display device according to any one of <1> to <23>, wherein the substrate is a flexible resin substrate.
<25> A method for manufacturing an organic EL display device according to any one of <1> to <24>, wherein at least a lower electrode, an organic layer including at least a light emitting layer, and an upper electrode are sequentially formed on a substrate. A step of forming an organic EL element portion, a step of forming a conductive etching protective film in electrical contact with the upper electrode, a step of forming a protective insulating film on the conductive etching protective film, and an etching material A method of manufacturing an organic EL display device, comprising: forming a contact hole in the protective insulating film; and forming a thin film field effect transistor on the protective insulating film, the source of the thin film field effect transistor Alternatively, the drain electrode and the conductive etching protective film are electrically connected through the contact hole. A method for manufacturing an organic EL display device.
<26> The method for manufacturing an organic EL display device according to <25>, wherein the etching rate of the conductive etching protective film is slower than the etching rate of the upper electrode by the etching material.
<27> The method for producing an organic EL display device according to <25> or <26>, wherein the etching rate of the conductive etching protective film is slower than the etching rate of the protective insulating film by the etching material. Method.
<28> The upper electrode is formed by resistance heating vapor deposition, and the conductive etching protective film is formed by sputtering, ion plating, or chemical vapor deposition (CVD) <25> The manufacturing method of the organic electroluminescence display in any one of-<27>.

A TFT using an amorphous oxide semiconductor can be formed at room temperature, and can be disposed on an organic EL element without damaging the organic EL element. In particular, by using an In—Ga—Zn—O-based oxide as an active layer, a TFT having a field effect mobility of 10 cm ² / Vs and an ON / OFF ratio exceeding 10 ³ can be manufactured. And an active layer containing an amorphous oxide semiconductor and a resistance layer, wherein the active layer is in contact with the gate insulating film, and the resistance is between the active layer and at least one of the source electrode and the drain electrode. By adopting a structure in which the layers are electrically connected, a TFT having both excellent OFF characteristics and high mobility can be formed. In particular, the substrate has at least the resistance layer and the active layer in layers, the active layer is in contact with the gate insulating film, and the resistance layer is in contact with at least one of the source electrode and the drain electrode. Found as an effective means. In the following description of the present invention, the active layer and the resistance layer may be collectively referred to as “semiconductor layer”.

  According to the present invention, an active organic EL display device having a TFT for driving the organic EL element on the organic EL element, having a high aperture ratio, high definition, high luminance, and long life, and its manufacture A method can be provided. In particular, according to the present invention, since the contact hole for electrically connecting the organic EL element and the TFT can be produced without damaging the organic EL element, the characteristics of the organic EL element are not impaired. In addition, it is possible to provide a long-life active organic EL display device and a manufacturing method thereof.

1. Organic EL Display Device The organic EL display device of the present invention is formed on a substrate, an organic EL element in which at least a lower electrode, an organic layer including at least a light emitting layer, and an upper electrode are sequentially formed, and the organic EL element. An organic EL display device having a TFT for driving the organic EL element, comprising a conductive etching protective film in electrical contact with the upper electrode between the upper electrode and the TFT, and the conductive etching A protective insulating film is provided between the protective film and the TFT, and the source or drain electrode of the TFT and the conductive etching protective film are electrically connected through a contact hole provided in the protective insulating film. Since TFT is arrange | positioned at the back surface of an organic EL element, the opening part which takes out light emission of an organic EL element can be taken large. Preferably, the lower electrode is a light transmissive electrode, and the upper electrode is a light reflective electrode.

1) Conductive etching protective film In the organic EL display device of the present invention, a conductive etching protective film is formed on the upper electrode of the organic EL element. The upper electrode of the organic EL element and the source or drain electrode of the driving TFT are electrically connected via the conductive etching protective film.
The conductive etching protective film has a function of preventing or reducing damage to the upper electrode of the organic EL element or the organic film when a contact hole is formed in the protective insulating film formed on the organic EL element by etching. Yes. Therefore, it is preferable that the etching rate of the conductive etching protective film with respect to the etching material for forming the contact hole in the protective insulating film is lower than the etching rate of the upper electrode of the organic EL element. More preferably, it is preferably slower than the etching rate of the protective insulating film. More preferably, it is 1/10 or less of the etching rate of the protective insulating film. In addition, since the upper electrode of the organic EL element and the source or drain electrode of the driving TFT are connected via a conductive etching protective film, conductive etching is required to electrically connect the organic EL element and the driving TFT. The protective film needs to be conductive.
Preferred materials, Al, Ag, Mo, Cr , Ti, Au, Pt, Ir, In, metal such as Sn or alloys _{thereof,, SnO 2, In 2 O} 3, ITO, conductive oxides such as IZO There are conductive semiconductors to which a large amount of impurities such as P-doped Si and B-doped Si are added. In particular, SnO ₂ is suitable as a conductive etching protective film because of good etching resistance.
The film thickness is preferably 10 nm to 10 μm. When the thickness is 10 nm or less, the function as an etching protective film is deteriorated. If the thickness is 10 μm or more, the process temperature rises when the conductive etching protective film is formed, which may damage the organic EL element.
As a method for forming the conductive etching protective film, the following method can be applied in which a dense thin film can be obtained rather than vacuum vapor deposition by heat resistance heating. Electron beam evaporation method, sputtering method, reactive sputtering method, MBE (molecular beam epitaxy) method, cluster ion beam method, ion plating method, plasma polymerization method (high frequency excitation ion plating method), plasma CVD method, laser CVD method , Thermal CVD method, gas source CVD method and the like. In particular, the sputtering method, the ion plating method, or the CVD method is preferable from the viewpoint of manufacturability such as a large area.

2) Protective insulating film In the organic EL display device of the present invention, the entire organic EL element is protected by a protective insulating film. The protective insulating film has a function of reducing damage to the organic EL element when a TFT is formed on the organic EL element, and a function of electrically insulating the organic EL element and the TFT. Further, it is more preferable that the protective insulating film has a function of preventing a substance that promotes element deterioration such as moisture and oxygen from entering the element.

Specific _{examples, MgO, SiO, SiO 2,} Al 2 O 3, GeO, NiO, CaO, BaO, Fe 2 O 3, Y 2 O 3, TiO metal oxides such as _{2, SiN x,} SiN x O metal nitrides such as _y , metal fluorides such as MgF ₂ , LiF, AlF ₃ , and CaF ₂ , polyethylene, polypropylene, polymethyl methacrylate, polyimide, polyurea, polytetrafluoroethylene, polychlorotrifluoroethylene, polydichlorodifluoroethylene , A copolymer of chlorotrifluoroethylene and dichlorodifluoroethylene, a copolymer obtained by copolymerizing a monomer mixture containing tetrafluoroethylene and at least one comonomer, and a copolymer main chain containing a cyclic structure. Fluorine copolymer, water-absorbing substance with water absorption of 1% or more, water absorption Examples include moisture-proof substances having a rate of 0.1% or less.

  The method for forming the protective insulating film is not particularly limited. For example, a vacuum deposition method, a sputtering method, a reactive sputtering method, an MBE (molecular beam epitaxy) method, a cluster ion beam method, an ion plating method, a plasma polymerization method ( High-frequency excitation ion plating method), plasma CVD method, laser CVD method, thermal CVD method, gas source CVD method, coating method, printing method, or transfer method can be applied.

  The thickness of the protective insulating film is preferably 10 nm to 10 μm. If the thickness exceeds 10 μm, it is difficult to form a contact hole for connecting the organic EL element and the TFT, and if it is less than 10 nm, the function as a protective film is lost.

  Since the upper electrode of the organic EL element and the source or drain electrode of the driving TFT need to be electrically connected, it is necessary to make a contact hole in the protective insulating film. As a method for forming the contact hole, there are a wet etching method using an etchant, a dry etching method using plasma, an etching method using a laser, and the like.

3) Structure Hereinafter, the organic EL display device of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a schematic cross-sectional view showing the configuration of the organic EL display device of the present invention.
On the substrate 100, an organic EL element portion having a lower electrode 30, an organic layer 32 including at least a light-emitting layer, and an upper electrode 34, a conductive etching protective film 109, a protective insulating film 106, and at least a source electrode 105a and a drain. A TFT portion including the electrode 105b, the active layer 104, the gate insulating film 103, and the gate electrode 102 is included. The conductive etching protection film 109 is arranged in a pattern at a position where the contact hole 108 is formed. One of the source electrode 105 a and the drain electrode 105 b and the conductive etching protective layer 109 are electrically connected by a contact hole 108 provided in the protective insulating film 106. That is, in this configuration, one of the source electrode and the drain electrode and the upper electrode are not directly electrically connected but are connected via the conductive etching protective film. The conductive etching protective film is formed by sputtering, ion plating, or CVD, and is a dense film. Therefore, it becomes a barrier against penetration of the etching material during contact hole fabrication, and the upper electrode and organic layer are damaged. Prevent receiving.
In this configuration, the substrate and the lower electrode are transparent, the upper electrode is light reflective, and light generated by light emission is extracted outside through the substrate.

FIG. 2 is a schematic cross-sectional view showing a configuration of a comparative organic EL display device.
The configuration of the organic EL display device is different from that of FIG. 1 in that it does not have a conductive etching protective film. One of the source electrode 115a and the drain electrode 115b and the upper electrode 44 are directly electrically connected. The upper electrode 44 is formed by a resistance heating vapor deposition method so as not to damage the organic layer. However, the obtained layer is dense and has many pinholes. Therefore, it does not serve as a barrier against the permeation of the etching material when the contact hole 118 is produced, and the etching material permeates and damages the upper electrode 44 and the organic layer 42 to deteriorate the organic EL display device.

In the present invention, the TFT is provided on the back surface opposite to the light extraction surface of the organic EL element. Since the TFT used in the present invention for the purpose described later has excellent ON / OFF ratio characteristics and can supply a high current, it is possible to reduce the size sufficiently to cope with a high-density arrangement of organic EL elements. It is possible to provide a wide opening of the element.
Therefore, an organic EL display device with high reliability, high definition, high brightness, and long life is provided.

2. TFT
The TFT used in the present invention has at least a gate electrode, a gate insulating film, an active layer, a source electrode, and a drain electrode in order, applies a voltage to the gate electrode, and controls a current flowing through the active layer, And an active element having a function of switching a current between the drain electrode and the drain electrode. As the TFT structure, either a staggered structure or an inverted staggered structure can be formed.

Preferably, the polarity of the TFT is N-type.
The organic EL element usually has a configuration in which the lower electrode is a transparent anode using ITO and the upper electrode is a light-reflective cathode using Al. The source or drain electrode of the driving TFT is preferably connected to the upper electrode, that is, the cathode of the organic EL element in terms of process or structure. For example, when the pixel circuit has a simple 2-transistor-1 capacity (2Tr-1C) configuration, the drain electrode of the TFT is connected to the cathode of the organic EL element, the anode of the organic EL element is grounded, and an N-type TFT is used. Particularly excellent performance is obtained in terms of driving characteristics. This is because the gate voltage of the driving TFT is not affected by the driving voltage of the organic EL element, so that stable driving is possible. Therefore, conventionally, it is not necessary to provide a compensation circuit such as 4Tr for stabilization, downsizing of the TFT portion is possible, and design of an organic EL display device with higher definition, higher luminance, and longer life is facilitated. .

Since the active layer in the present invention is formed on an organic EL device, an organic transistor, an oxide semiconductor, a carbon nanotube, or the like that can be formed at a low temperature is preferable. In particular, from the viewpoint of mobility and driving stability, the active layer is preferably an oxide semiconductor, particularly an amorphous oxide semiconductor.
As a more preferable TFT structure in the present invention, at least a gate electrode, a gate insulating film, a semiconductor layer composed of an active layer and a resistance layer, a source electrode and a drain electrode are sequentially provided, and the electric conductivity of the resistance layer is The electrical conductivity of the active layer is smaller than the active layer, the active layer is in contact with the gate insulating film, and the resistive layer is electrically connected between the active layer and at least one of the source electrode and the drain electrode. .
More preferably, the substrate includes at least the resistance layer and the active layer in layers, the active layer is in contact with the gate insulating film, and the resistance layer is in contact with at least one of the source electrode and the drain electrode.
From the viewpoint of operational stability, it is preferable that the thickness of the resistance layer is larger than the thickness of the active layer. More preferably, the ratio of the thickness of the resistance layer to the thickness of the active layer is more than 1 and 100 or less, more preferably more than 1 and 10 or less.
The thickness of the active layer is preferably 1 nm to 100 nm, more preferably 2.5 nm to 30 nm. The thickness of the resistance layer is preferably 5 nm or more and 500 nm or less, and more preferably 10 nm or more and 100 nm or less.
Moreover, as another aspect, the aspect in which the electrical conductivity between the said resistance layer and the said active layer is changing continuously in the said semiconductor layer is also preferable.
Preferably, the oxygen concentration of the active layer is lower than the oxygen concentration of the resistance layer.
Preferably, the oxide semiconductor includes at least one selected from the group consisting of In, Ga, and Zn, or a composite oxide thereof. More preferably, the oxide semiconductor contains In and Zn, and the composition ratio of Zn and In (represented by the ratio of Zn to In, Zn / In) of the resistance layer is greater than the composition ratio Zn / In of the active layer. large. Preferably, the Zn / In ratio of the resistance layer is 3% or more larger than the Zn / In ratio of the active layer, and more preferably 10% or more.
The ratio of the electrical conductivity of the active layer to the electrical conductivity of the resistive layer (the electrical conductivity of the active layer / the electrical conductivity of the resistive layer) is preferably 10 ^{1 to} 10 ¹⁰ , more preferably, 10 ² or more and 10 ⁸ or less.
Preferably, the substrate is a flexible resin substrate.

Preferably, the electric conductivity of the active layer is 10 ⁻⁴ Scm ⁻¹ or more and less than 10 ² Scm ⁻¹ . More preferably, it is 10 ⁻¹ Scm ⁻¹ or more and less than 10 ² Scm ⁻¹ . The electric conductivity of the resistance layer is preferably 10 ⁻² Scm ⁻¹ or less, more preferably 10 ⁻⁹ Scm ⁻¹ or more and less than 10 ⁻³ Scm ^−1, which is smaller than the electric conductivity of the active layer.
When the electric conductivity of the active layer is less than 10 ⁻⁴ Scm ⁻¹ , high field effect mobility cannot be obtained, and when it is 10 ² Scm ⁻¹ or more, the OFF current increases and good ON / OFF is achieved. Since the ratio cannot be obtained, it is not preferable.

Next, a more preferable TFT structure in the present invention will be described in detail with reference to the drawings.
1) Structure Next, the structure of the TFT in the present invention will be described in detail with reference to the drawings.
FIG. 3 is a schematic diagram showing an example of an inverted stagger structure of the TFT of the present invention. In the case where the substrate 1 is a flexible substrate such as a plastic film, an insulating layer 6 is disposed on one surface of the substrate 1, and a gate electrode 2, a gate insulating film 3, an active layer 4-1, and a resistance layer 4- 2 and a source electrode 5-1 and a drain electrode 5-2 are provided on the surface thereof. The active layer 4-1 is in contact with the gate insulating film 3, and the resistance layer 4-2 is in contact with the source electrode 5-1 and the drain electrode 5-2. The composition of the active layer 4-1 and the resistive layer 4-2 is such that the electrical conductivity of the active layer 4-1 when no voltage is applied to the gate electrode is greater than the electrical conductivity of the resistive layer 4-2. Is determined. Here, for the active layer and the resistance layer, an oxide semiconductor disclosed in JP-A-2006-165529, for example, an In—Ga—Zn—O-based oxide semiconductor is used. These oxide semiconductors are known to have higher electron mobility as the electron carrier concentration is higher. That is, the higher the electric conductivity, the higher the electron mobility.
According to the structure of the present invention, when the TFT is in an ON state where a voltage is applied to the gate electrode, the active layer serving as a channel has a large electric conductivity, so that the field effect mobility of the transistor is high, High ON current can be obtained. Since the electric resistance of the resistance layer is small in the OFF state and the resistance of the resistance layer is high, the OFF current is kept low, so that the ON / OFF ratio characteristics are greatly improved.

  Although not shown in the figure, the gist of the present invention is that the semiconductor layer is provided so that the electrical conductivity of the semiconductor layer in the vicinity of the gate insulating film is larger than the electrical conductivity of the semiconductor layer in the vicinity of the source electrode and the drain electrode. In particular, as long as the state is obtained, the means for achieving the state is not limited to providing a plurality of semiconductor layers as shown in FIG. The electrical conductivity may change continuously.

  FIG. 4 is a schematic diagram showing an example of a top gate structure of the TFT of the present invention. When the substrate 1 is a flexible substrate such as a plastic film, an insulating layer 16 is disposed on one surface of the substrate 11, a source electrode 5-11 and a drain electrode 5-12 are provided on the insulating layer, and the resistance layer 4 −12, after the active layer 4-11 is laminated, the gate insulating film 13 and the gate electrode 12 are disposed. As in the inverted staggered configuration, the active layer 4-11 (large electrical conductivity layer) is in contact with the gate insulating film 13, and the resistance layer 4-12 (small electrical conductivity layer) is the source electrode 5-11 and the drain electrode. Contact 5-12. The composition of the active layer 4-11 and the resistive layer 4-12 so that the electrical conductivity of the active layer 4-11 when no voltage is applied to the gate electrode is greater than the electrical conductivity of the resistive layer 4-12. Is determined.

2) Electric conductivity The electric conductivity of the active layer and the resistance layer in the present invention will be described.
The electrical conductivity is a physical property value indicating the ease of electrical conduction of a substance. When the carrier concentration n and carrier mobility μ and e of the substance are assumed to be elementary charge, the electrical conductivity σ of the substance is expressed by the following equation. expressed.
σ = neμ
When the active layer or the resistance layer is an n-type semiconductor, the carriers are electrons, the carrier concentration indicates the electron carrier concentration, and the carrier mobility indicates the electron mobility. Similarly, when the active layer or the resistance layer is a p-type semiconductor, the carriers are holes, the carrier concentration indicates the hole carrier concentration, and the carrier mobility indicates the hole mobility. The carrier concentration and carrier mobility of the substance can be obtained by Hall measurement.
<How to find electrical conductivity>
By measuring the sheet resistance of a film whose thickness is known, the electrical conductivity of the film can be determined. Although the electrical conductivity of a semiconductor varies with temperature, the electrical conductivity described in the text indicates the electrical conductivity at room temperature (20 ° C.).

3) Gate insulating film As the gate insulating film, at least two insulators such as SiO ₂ , SiN _x , SiON, Al ₂ O ₃ , Y ₂ O ₃ , Ta ₂ O ₅ , or HfO ₂ , or a compound thereof are used. The mixed crystal compound containing the above is used. A polymer insulator such as polyimide can also be used as the gate insulating film.

The thickness of the gate insulating film is preferably 10 nm to 10 μm. The gate insulating film needs to be thickened to some extent in order to reduce leakage current and increase voltage resistance. However, increasing the thickness of the gate insulating film results in an increase in the driving voltage of the TFT. Therefore, it is more preferable that the film thickness of the gate insulating film is 50 nm to 1000 nm for an inorganic insulator and 0.5 μm to 5 μm for a polymer insulator. In particular, it is particularly preferable to use a high dielectric constant insulator such as HfO ₂ for the gate insulating film because TFT driving at a low voltage is possible even if the film thickness is increased.

4) Active layer and resistance layer It is preferable to use an oxide semiconductor for the semiconductor layer constituting the active layer and the resistance layer used in the present invention. In particular, an amorphous oxide semiconductor is more preferable. An oxide semiconductor, particularly an amorphous oxide semiconductor, can be formed at a low temperature, and thus can be formed over a flexible resin substrate such as a plastic. Good amorphous oxide semiconductors that can be manufactured at low temperatures include oxides containing In, oxides containing In and Zn, In, Ga, and Zn as disclosed in JP-A-2006-165529. It is known that InGaO ₃ (ZnO) _m (m is a natural number of less than 6) is preferable as the composition structure. These are n-type semiconductors whose carriers are electrons. Of _{course, ZnO · Rh 2 O 3,} CuGaO 2, a p-type oxide semiconductor such as SrCu ₂ O ₂ may be used for the semiconductor layer.

Specifically, the amorphous oxide semiconductor according to the present invention includes In—Ga—Zn—O, and the composition in the crystalline state is represented by InGaO ₃ (ZnO) _m (m is a natural number of less than 6). A physical semiconductor is preferred. In particular, InGaZnO ₄ is more preferable. As an amorphous oxide semiconductor having this composition, the electron mobility tends to increase as the electrical conductivity increases. Japanese Patent Laid-Open No. 2006-165529 discloses that the electric conductivity can be controlled by the oxygen partial pressure during film formation.
Of course, the semiconductor layer can be applied not only to an oxide semiconductor but also to an inorganic semiconductor such as Si and Ge, a compound semiconductor such as GaAs, and an organic semiconductor material such as pentacene and polythiophene.

<Electrical conductivity of active layer and resistance layer>
In the present invention, the active layer is close to the gate insulating film and has a higher electric conductivity than the resistance layer close to the source electrode and the drain electrode.
Preferably, the electrical conductivity of the active layer in contact with the gate insulating film is larger than the electrical conductivity of the resistive layer in contact with the source electrode and the drain electrode, more preferably, the resistive layer having the electrical conductivity of the active layer. The ratio of the electric conductivity to the electric conductivity (the electric conductivity of the active layer / the electric conductivity of the resistance layer) is preferably 10 ¹ or more and 10 ¹⁰ or less, more preferably 10 ² or more and 10 ⁸ or less. Preferably, the electric conductivity of the active layer is 10 ⁻⁴ Scm ⁻¹ or more and less than 10 ² Scm ⁻¹ . More preferably, it is 10 ⁻¹ Scm ⁻¹ or more and less than 10 ² Scm ⁻¹ . The electric conductivity of the resistance layer is preferably 10 ⁻¹ Scm ⁻¹ or less, more preferably 10 ⁻⁹ Scm ⁻¹ or more and 10 ⁻³ Scm ⁻¹ or less.
<Thickness of active layer and resistance layer>
The resistance layer is preferably thicker than the active layer. More preferably, the ratio of the thickness of the resistance layer to the thickness of the active layer is more than 1 and 100 or less, more preferably more than 1 and 10 or less.
The thickness of the active layer is preferably 1 nm to 100 nm, more preferably 2.5 nm to 30 nm. The thickness of the resistance layer is preferably 5 nm or more and 500 nm or less, and more preferably 10 nm or more and 100 nm or less.

By using a semiconductor layer composed of an active layer and a resistance layer having the above structure, a TFT transistor having a high mobility of 10 cm ² / (V · sec) or more and an ON / OFF ratio of 10 ⁶ or more is obtained. Can be realized.

<Measuring means for electrical conductivity>
As described above, the electric conductivity of the semiconductor layer in the present invention is adjusted to be larger in the vicinity of the gate insulating film (active layer) than in the vicinity of the source and drain electrodes (resistance layer) of the semiconductor layer.
As a means for adjusting the electrical conductivity, the following means can be exemplified when the semiconductor layer is an oxide semiconductor.
(1) Adjustment by oxygen defect It is known that when an oxygen defect is formed in an oxide semiconductor, carrier electrons are generated and electric conductivity is increased. Therefore, the electric conductivity of the oxide semiconductor can be controlled by adjusting the amount of oxygen defects. Specific methods for controlling the amount of oxygen defects include oxygen partial pressure during film formation, oxygen concentration and treatment time during post-treatment after film formation, and the like. Specific examples of post-treatment include heat treatment at 100 ° C. or higher, oxygen plasma, and UV ozone treatment. Among these methods, a method of controlling the oxygen partial pressure during film formation is preferable from the viewpoint of productivity. JP-A-2006-165529 discloses that the electrical conductivity of an oxide semiconductor can be controlled by adjusting the oxygen partial pressure during film formation, and this technique can be used.
(2) Adjustment by composition ratio It is known that the electrical conductivity changes by changing the metal composition ratio of an oxide semiconductor. For example, Japanese Patent Laid-Open No. 2006-165529 discloses that in InGaZn _1-X Mg _X O ₄ , the electrical conductivity decreases as the Mg ratio increases. In addition, in the oxide system of (In ₂ O ₃ ) _1-X (ZnO) _X , it has been reported that when the Zn / In ratio is 10% or more, the electrical conductivity decreases as the Zn ratio increases. ("New development of transparent conductive film II", CMC Publishing, P.34-35). As specific methods for changing these composition ratios, for example, in a film formation method by sputtering, targets having different composition ratios are used. Alternatively, it is possible to change the composition ratio of the film by co-sputtering with a multi-source target and individually adjusting the sputtering rate.
(3) Adjustment by impurities By adding an element such as Li, Na, Mn, Ni, Pd, Cu, Cd, C, N, or P to the oxide semiconductor as an impurity, reducing the electron carrier concentration, That is, it is disclosed in Japanese Patent Application Laid-Open No. 2006-165529 that electric conductivity can be reduced. As a method for adding an impurity, an oxide semiconductor and an impurity element are co-evaporated, an ion of the impurity element is added to the formed oxide semiconductor film by an ion doping method, or the like.
(4) Adjustment by oxide semiconductor material In the above (1) to (3), the method for adjusting the electric conductivity in the same oxide semiconductor system has been described. Of course, the electric conductivity can be changed by changing the oxide semiconductor material. You can change the degree. For example, it is generally known that a SnO ₂ oxide semiconductor has a lower electrical conductivity than an In ₂ O ₃ oxide semiconductor. By changing the oxide semiconductor material in this manner, the electric conductivity can be adjusted. In particular, as an oxide material having low electrical conductivity, oxide insulator materials such as Al ₂ O ₃ , Ga ₂ O ₃ , ZrO ₂ , Y ₂ O ₃ , Ta ₂ O ₃ , MgO, or HfO ₃ are known. These can also be used.
As means for adjusting the electrical conductivity, the above methods (1) to (4) may be used alone or in combination.

<Method for forming semiconductor layer>
As a method for forming the semiconductor layer, it is preferable to use a vapor phase film forming method with a polycrystalline sintered body of an oxide semiconductor as a target. Among vapor deposition methods, sputtering and pulsed laser deposition (PLD) are suitable. Furthermore, the sputtering method is preferable from the viewpoint of mass productivity.

  For example, the film is formed by controlling the degree of vacuum and the oxygen flow rate by RF magnetron sputtering deposition. The greater the oxygen flow rate, the smaller the electrical conductivity.

The formed film can be confirmed to be an amorphous film by a known X-ray diffraction method.
The film thickness can be determined by stylus surface shape measurement. The composition ratio can be determined by an RBS (Rutherford backscattering) analysis method.

5) Gate electrode Examples of the gate electrode in the present invention include metals such as Al, Mo, Cr, Ta, Ti, Au, and Ag, alloys such as Al-Nd and APC, tin oxide, zinc oxide, indium oxide, and oxide. Preferable examples include metal oxide conductive films such as indium tin (ITO) and indium zinc oxide (IZO), organic conductive compounds such as polyaniline, polythiophene, and polypyrrole, or mixtures thereof.
The thickness of the gate electrode is preferably 10 nm or more and 1000 nm or less.

  The electrode film formation method is not particularly limited, and may be a printing method, a wet method such as a coating method, a physical method such as a vacuum deposition method, a sputtering method, or an ion plating method, a CVD method, a plasma CVD method, or the like. It can be formed on the substrate according to a method appropriately selected in consideration of suitability with the material from among chemical methods. For example, when ITO is selected, it can be performed according to a direct current or high frequency sputtering method, a vacuum deposition method, an ion plating method, or the like. When an organic conductive compound is selected as the material for the gate electrode, it can be performed according to a wet film forming method.

6) Source electrode and drain electrode Examples of the source electrode and drain electrode material in the present invention include metals such as Al, Mo, Cr, Ta, Ti, Au, and Ag, alloys such as Al-Nd and APC, tin oxide, and oxidation. Preferred examples include metal oxide conductive films such as zinc, indium oxide, indium tin oxide (ITO), and zinc indium oxide (IZO), organic conductive compounds such as polyaniline, polythiophene, and polypyrrole, or mixtures thereof.
The thickness of the source electrode and the drain electrode is preferably 10 nm or more and 1000 nm or less.

  The electrode film formation method is not particularly limited, and may be a printing method, a wet method such as a coating method, a physical method such as a vacuum deposition method, a sputtering method, or an ion plating method, a CVD method, a plasma CVD method, or the like. It can be formed on the substrate according to a method appropriately selected in consideration of suitability with the material from among chemical methods. For example, when ITO is selected, it can be performed according to a direct current or high frequency sputtering method, a vacuum deposition method, an ion plating method, or the like. Further, when an organic conductive compound is selected as a material for the source electrode and the drain electrode, it can be performed according to a wet film forming method.

7) Protective insulating film If necessary, a protective insulating film may be provided on the TFT. The protective insulating film has the purpose of protecting the semiconductor layer (the active layer and the resistance layer) from deterioration due to the atmosphere and the purpose of insulating the electronic device manufactured on the TFT.

Specific examples of the protective insulating film material include metal oxides such as MgO, SiO, SiO ₂ , Al ₂ O ₃ , GeO, NiO, CaO, BaO, Fe ₂ O ₃ , Y ₂ O ₃ , or TiO ₂ , SiN metal nitrides such as _x and SiN _x O _y , metal fluorides such as MgF ₂ , LiF, AlF ₃ , and CaF ₂ , polyethylene, polypropylene, polymethyl methacrylate, polyimide, polyurea, polytetrafluoroethylene, polychlorotrifluoro Copolymer obtained by copolymerizing ethylene, polydichlorodifluoroethylene, a copolymer of chlorotrifluoroethylene and dichlorodifluoroethylene, a monomer mixture containing tetrafluoroethylene and at least one comonomer, and a copolymer main chain Fluorine-containing copolymer having a cyclic structure, water absorption of 1% or less The above water-absorbing substances, moisture-proof substances having a water absorption rate of 0.1% or less, and the like are mentioned.

  The method for forming the protective insulating film is not particularly limited. For example, a vacuum deposition method, a sputtering method, a reactive sputtering method, an MBE (molecular beam epitaxy) method, a cluster ion beam method, an ion plating method, a plasma polymerization method ( High-frequency excitation ion plating method), plasma CVD method, laser CVD method, thermal CVD method, gas source CVD method, coating method, printing method, or transfer method can be applied.

8) Post-treatment If necessary, heat treatment may be performed as a post-treatment of the TFT. The heat treatment is performed at a temperature of 100 ° C. or higher in the air or in a nitrogen atmosphere. The heat treatment may be performed after the semiconductor layer is formed or at the end of the TFT manufacturing process. By performing the heat treatment, there are effects such as suppression of in-plane variation in TFT characteristics and improvement in driving stability.

3. Organic EL Element The organic EL element of the present invention has a lower electrode and an upper electrode on a substrate, and an organic compound layer including an organic light emitting layer (hereinafter sometimes simply referred to as “light emitting layer”) between both electrodes. Have The upper electrode is connected to the source electrode or drain electrode of the driving transistor. In view of the properties of the light emitting element, at least one of the lower electrode and the upper electrode is preferably transparent. One of the lower electrode and the upper electrode is an anode, and the other is a cathode. Usually, the lower electrode is an anode and the upper electrode is a cathode.

In the present invention, the organic compound layer is preferably laminated in the order of the hole transport layer, the light emitting layer, and the electron transport layer from the anode side. Further, a hole injection layer is provided between the hole transport layer and the anode, and / or an electron transporting intermediate layer is provided between the light emitting layer and the electron transport layer. Further, a hole transporting intermediate layer may be provided between the light emitting layer and the hole transport layer, and similarly, an electron injection layer may be provided between the cathode and the electron transport layer.
Each layer may be divided into a plurality of secondary layers.

  Each layer constituting the organic compound layer can be suitably formed by any of dry film forming methods such as vapor deposition and sputtering, transfer methods, printing methods, coating methods, ink jet methods, and spray methods.

  Next, elements constituting the light emitting device of the present invention will be described in detail.

(substrate)
The substrate used in the present invention is preferably a substrate that does not scatter or attenuate light emitted from the organic compound layer. Specific examples thereof include zirconia stabilized yttrium (YSZ), inorganic materials such as glass, polyesters such as polyethylene terephthalate, polybutylene phthalate, and polyethylene naphthalate, polystyrene, polycarbonate, polyethersulfone, polyarylate, polyimide, and polycycloolefin. , Norbornene resins, and organic materials such as poly (chlorotrifluoroethylene).
For example, when glass is used as the substrate, alkali-free glass is preferably used as the material in order to reduce ions eluted from the glass. Moreover, when using soda-lime glass, it is preferable to use what gave barrier coatings, such as a silica. In the case of an organic material, it is preferable that it is excellent in heat resistance, dimensional stability, solvent resistance, electrical insulation, and workability.

  There is no restriction | limiting in particular about the shape of a board | substrate, a structure, a magnitude | size, It can select suitably according to the use, purpose, etc. of a light emitting element. In general, the shape of the substrate is preferably a plate shape. The substrate structure may be a single layer structure, a laminated structure, may be formed of a single member, or may be formed of two or more members.

  The substrate may be colorless and transparent or colored and transparent, but is preferably colorless and transparent in that it does not scatter or attenuate light emitted from the organic light emitting layer.

The substrate can be provided with a moisture permeation preventing layer (gas barrier layer) on the front surface or the back surface.
As a material for the moisture permeation preventive layer (gas barrier layer), inorganic materials such as silicon nitride and silicon oxide are preferably used. The moisture permeation preventing layer (gas barrier layer) can be formed by, for example, a high frequency sputtering method.
When a thermoplastic substrate is used, a hard coat layer, an undercoat layer, or the like may be further provided as necessary.

(anode)
The anode usually has a function as an electrode for supplying holes to the organic compound layer, and there is no particular limitation on the shape, structure, size, etc., depending on the use and purpose of the light-emitting element. , Can be appropriately selected from known electrode materials. As described above, the anode is usually provided as a transparent anode.

  Suitable examples of the material for the anode include metals, alloys, metal oxides, conductive compounds, and mixtures thereof. Specific examples of the anode material include conductive metals such as tin oxide doped with antimony and fluorine (ATO, FTO), tin oxide, zinc oxide, indium oxide, indium tin oxide (ITO), and indium zinc oxide (IZO). Metals such as oxides, gold, silver, chromium, nickel, and mixtures or laminates of these metals and conductive metal oxides, inorganic conductive materials such as copper iodide and copper sulfide, polyaniline, polythiophene, polypyrrole, etc. Organic conductive materials, and a laminate of these and ITO. Among these, conductive metal oxides are preferable, and ITO is particularly preferable from the viewpoints of productivity, high conductivity, transparency, and the like.

  The anode is composed of, for example, a wet method such as a printing method and a coating method, a physical method such as a vacuum deposition method, a sputtering method, and an ion plating method, and a chemical method such as a CVD and a plasma CVD method. It can be formed on the substrate according to a method appropriately selected in consideration of suitability with the material to be processed. For example, when ITO is selected as the anode material, the anode can be formed according to a direct current or high frequency sputtering method, a vacuum deposition method, an ion plating method, or the like.

  In the organic electroluminescent element of the present invention, the formation position of the anode is not particularly limited and can be appropriately selected according to the use and purpose of the light emitting element. Is preferably formed on the substrate. In this case, the anode may be formed on the entire one surface of the substrate, or may be formed on a part thereof.

  The patterning for forming the anode may be performed by chemical etching such as photolithography, or may be performed by physical etching such as laser, or vacuum deposition or sputtering with a mask overlapped. It may be performed by a lift-off method or a printing method.

  The thickness of the anode can be appropriately selected depending on the material constituting the anode and cannot be generally defined, but is usually about 10 nm to 50 μm, and preferably 50 nm to 20 μm.

The resistance value of the anode is preferably 10 ³ Ω / □ or less, and more preferably 10 ² Ω / □ or less. When the anode is transparent, it may be colorless and transparent or colored and transparent. In order to take out light emission from the transparent anode side, the transmittance is preferably 60% or more, and more preferably 70% or more.

  Note that the transparent anode is described in detail in Yutaka Sawada's “New Development of Transparent Electrode Film” published by CMC (1999), and the matters described here can be applied to the present invention. In the case of using a plastic substrate having low heat resistance, a transparent anode formed using ITO or IZO at a low temperature of 150 ° C. or lower is preferable.

(cathode)
The cathode usually has a function as an electrode for injecting electrons into the organic compound layer, and there is no particular limitation on the shape, structure, size, etc., depending on the use and purpose of the light-emitting element, It can select suitably from well-known electrode materials.

  Examples of the material constituting the cathode include metals, alloys, metal oxides, electrically conductive compounds, and mixtures thereof. Specific examples include alkali metals (eg, LI, Na, K, Cs, etc.), alkaline earth metals (eg, Mg, Ca, etc.), gold, silver, lead, aluminum, sodium-potassium alloys, lithium-aluminum alloys, magnesium. -Rare earth metals such as silver alloys, indium and ytterbium. These may be used alone, but two or more can be suitably used in combination from the viewpoint of achieving both stability and electron injection.

Among these, as a material constituting the cathode, an alkali metal or an alkaline earth metal is preferable from the viewpoint of electron injecting property, and a material mainly composed of aluminum is preferable from the viewpoint of excellent storage stability.
The material mainly composed of aluminum is aluminum alone, an alloy of aluminum and 0.01% by mass to 10% by mass of alkali metal or alkaline earth metal, or a mixture thereof (for example, lithium-aluminum alloy, magnesium-aluminum alloy). Etc.).

  The materials for the cathode are described in detail in JP-A-2-15595 and JP-A-5-121172, and the materials described in these public relations can also be applied in the present invention.

There is no restriction | limiting in particular about the formation method of a cathode, According to a well-known method, it can carry out.
For example, the cathode described above is configured from a wet method such as a printing method or a coating method, a physical method such as a vacuum deposition method, a sputtering method, or an ion plating method, or a chemical method such as CVD or plasma CVD method. It can be formed according to a method appropriately selected in consideration of suitability with the material. For example, when a metal or the like is selected as the cathode material, one or more of them can be simultaneously or sequentially performed according to a sputtering method or the like.

  Patterning when forming the cathode may be performed by chemical etching such as photolithography, physical etching by laser, or the like, or by vacuum deposition or sputtering with the mask overlaid. It may be performed by a lift-off method or a printing method.

In the present invention, the cathode formation position is not particularly limited, and may be formed on the entire organic compound layer or a part thereof.
Further, a dielectric layer made of an alkali metal or alkaline earth metal fluoride or oxide may be inserted between the cathode and the organic compound layer with a thickness of 0.1 nm to 5 nm. This dielectric layer can also be regarded as a kind of electron injection layer. The dielectric layer can be formed by, for example, a vacuum deposition method, a sputtering method, an ion plating method, or the like.

The thickness of the cathode can be appropriately selected depending on the material constituting the cathode and cannot be generally defined, but is usually about 10 nm to 5 μm, and preferably 50 nm to 1 μm.
Further, the cathode may be transparent or opaque. The transparent cathode can be formed by depositing a thin cathode material to a thickness of 1 nm to 10 nm and further laminating a transparent conductive material such as ITO or IZO.

(Organic compound layer)
The organic compound layer in the present invention will be described.
The organic EL device of the present invention has at least one organic compound layer including a light emitting layer. As described above, other organic compound layers other than the light emitting layer include a hole transport layer, an electron transport layer, a positive layer, Examples thereof include a hole blocking layer, an electron blocking layer, a hole injection layer, and an electron injection layer.

  In the organic EL device of the present invention, each layer constituting the organic compound layer is preferably formed by any of dry film forming methods such as vapor deposition and sputtering, wet coating methods, transfer methods, printing methods, and ink jet methods. Can do.

(Light emitting layer)
The organic light emitting layer receives holes from the anode, the hole injection layer, or the hole transport layer when an electric field is applied, receives electrons from the cathode, the electron injection layer, or the electron transport layer, and recombines holes and electrons. It is a layer having a function of providing a field to emit light.
The light emitting layer in the present invention may be composed only of a light emitting material, or may be a mixed layer of a host material and a light emitting dopant. The luminescent dopant may be a fluorescent material or a phosphorescent material, and may be two or more kinds. The host material is preferably a charge transport material. The host material may be one type or two or more types, and examples thereof include a configuration in which an electron transporting host material and a hole transporting host material are mixed. Further, the light emitting layer may include a material that does not have charge transporting properties and does not emit light.
Further, the light emitting layer may be a single layer or two or more layers, and each layer may emit light in different emission colors.

As the luminescent dopant in the present invention, any of phosphorescent luminescent materials and fluorescent luminescent materials can be used as the dopant.
The light emitting layer in the present invention can contain two or more kinds of light emitting dopants in order to improve color purity and to broaden the light emission wavelength region. The luminescent dopant in the present invention is a dopant satisfying at least one of the following relationships with the host compound: 1.2 eV>ΔIp> 0.2 eV and 1.2 eV>ΔEa> 0.2 eV. Is preferable from the viewpoint of driving durability.

《Phosphorescent dopant》
In general, examples of the phosphorescent light-emitting dopant include complexes containing a transition metal atom or a lanthanoid atom.
For example, the transition metal atom is not particularly limited, but preferably includes ruthenium, rhodium, palladium, tungsten, rhenium, osmium, iridium, gold, silver, copper, and platinum, and more preferably rhenium, iridium. And platinum, more preferably iridium and platinum.
Examples of the lanthanoid atom include lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium. Among these lanthanoid atoms, neodymium, europium, and gadolinium are preferable.

Examples of the ligand of the complex include G.I. Wilkinson et al., Comprehensive Coordination Chemistry, Pergamon Press, 1987, H.C. Examples include ligands described in Yersin's "Photochemistry and Photophysics of Coordination Compounds" published by Springer-Verlag 1987, Akio Yamamoto "Organic Metal Chemistry-Fundamentals and Applications-" .
The specific ligand is preferably a halogen ligand (preferably a chlorine ligand) or an aromatic carbocyclic ligand (for example, preferably 5 to 30 carbon atoms, more preferably 6 to 6 carbon atoms). 30 and more preferably 6 to 20 carbon atoms, particularly preferably 6 to 12 carbon atoms, such as cyclopentadienyl anion, benzene anion, or naphthyl anion), nitrogen-containing heterocyclic ligand (for example, preferably Has 5 to 30 carbon atoms, more preferably 6 to 30 carbon atoms, still more preferably 6 to 20 carbon atoms, particularly preferably 6 to 12 carbon atoms, and phenylpyridine, benzoquinoline, quinolinol, bipyridyl, or phenanthroline. Etc.), diketone ligand (for example, acetylacetone, etc.), carboxylic acid ligand (for example, preferably 2-30 carbon atoms, and more) Preferably, it has 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, such as an acetic acid ligand), an alcoholate ligand (for example, preferably 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms). More preferably, it has 6 to 20 carbon atoms, such as phenolate ligand), silyloxy ligand (for example, preferably 3 to 40 carbon atoms, more preferably 3 to 30 carbon atoms, still more preferably 3 to 3 carbon atoms). 20 such as trimethylsilyloxy ligand, dimethyl-tert-butylsilyloxy ligand, triphenylsilyloxy ligand), carbon monoxide ligand, isonitrile ligand, cyano ligand, Phosphorus ligand (preferably having 3 to 40 carbon atoms, more preferably 3 to 30 carbon atoms, still more preferably 3 to 20 carbon atoms, and particularly preferably 6 to 20 carbon atoms. A rephenylphosphine ligand), a thiolato ligand (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, still more preferably 6 to 20 carbon atoms, such as a phenylthiolato ligand) ), A phosphine oxide ligand (preferably having 3 to 30 carbon atoms, more preferably 8 to 30 carbon atoms, still more preferably 18 to 30 carbon atoms, such as a triphenylphosphine oxide ligand). More preferably, it is a nitrogen-containing heterocyclic ligand.
The complex may have one transition metal atom in the compound, or may be a so-called binuclear complex having two or more. Different metal atoms may be contained at the same time.

  Among these, specific examples of the luminescent dopant include, for example, US6303238B1, US6097147, WO00 / 57676, WO00 / 70655, WO01 / 08230, WO01 / 39234A2, WO01 / 41512A1, WO02 / 02714A2, WO02 / 15645A1, WO02 / 44189A1. , WO 05/19373 A2, JP 2001-247859, JP 2002-302671, JP 2002-117978, JP 2003-133074, JP 2002-235076, JP 2003-123982, JP 2002-170684, EP 12112257, Special JP 2002-226495, JP 2002-234894, JP 2001247478, JP 2001-298470, JP 2002 73674, JP 2002-203678, JP 2002-203679, JP 2004-357799, JP 2006-256999, JP 2007-19462, JP 2007-84635, JP 2007-96259, and the like. Phosphorescent compounds and the like are mentioned. Among them, more preferable luminescent dopants include Ir complex, Pt complex, Cu complex, Re complex, W complex, Rh complex, Ru complex, Pd complex, Os complex, Eu complex, Tb complex. , Gd complex, Dy complex, and Ce complex. Particularly preferred is an Ir complex, a Pt complex, or a Re complex, among which an Ir complex or a Pt complex containing at least one coordination mode of a metal-carbon bond, a metal-nitrogen bond, a metal-oxygen bond, and a metal-sulfur bond. Or a Re complex. Furthermore, from the viewpoints of luminous efficiency, driving durability, chromaticity, etc., an Ir complex, a Pt complex, or a Re complex containing a tridentate or higher polydentate ligand is particularly preferable.

《Fluorescent luminescent dopant》
As the fluorescent light-emitting dopant, generally, benzoxazole, benzimidazole, benzothiazole, styrylbenzene, polyphenyl, diphenylbutadiene, tetraphenylbutadiene, naphthalimide, coumarin, pyran, perinone, oxadiazole, aldazine, Pyraridin, cyclopentadiene, bisstyrylanthracene, quinacridone, pyrrolopyridine, thiadiazolopyridine, cyclopentadiene, styrylamine, aromatic dimethylidin compounds, condensed polycyclic aromatic compounds (anthracene, phenanthroline, pyrene, perylene, rubrene, pentacene, etc. ), 8-quinolinol metal complexes, various metal complexes represented by pyromethene complexes and rare earth complexes, polythiophene, polyphenylene, polyphenylene Polymeric compounds such as vinylene, organic silane, and the like, and their derivatives.

  Among these, specific examples of the luminescent dopant include the following, but are not limited thereto.

  The light-emitting dopant in the light-emitting layer is contained in an amount of 0.1% by mass to 50% by mass with respect to the total compound mass generally forming the light-emitting layer in the light-emitting layer. To 1 mass% to 50 mass%, and more preferably 2 mass% to 40 mass%.

  Although the thickness of the light emitting layer is not particularly limited, it is usually preferably 2 nm to 500 nm, more preferably 3 nm to 200 nm, and more preferably 5 nm to 100 nm from the viewpoint of external quantum efficiency. More preferably.

<Host material>
As the host material used in the present invention, a hole transporting host material excellent in hole transportability (sometimes referred to as a hole transportable host) and an electron transporting host compound excellent in electron transportability (electron transportability) May be described as a host).

《Hole-transporting host》
Specific examples of the hole-transporting host used in the present invention include the following materials.
Pyrrole, indole, carbazole, azaindole, azacarbazole, triazole, oxazole, oxadiazole, pyrazole, imidazole, thiophene, polyarylalkane, pyrazoline, pyrazolone, phenylenediamine, arylamine, amino-substituted chalcone, styrylanthracene, fluorenone, hydrazone , Stilbene, silazane, aromatic tertiary amine compound, styrylamine compound, aromatic dimethylidin compound, porphyrin compound, polysilane compound, poly (N-vinylcarbazole), aniline copolymer, thiophene oligomer, polythiophene, etc. Conductive polymer oligomers, organic silanes, carbon films, and derivatives thereof.
Preferred are indole derivatives, carbazole derivatives, aromatic tertiary amine compounds, and thiophene derivatives, and more preferred are those having a carbazole group in the molecule. In particular, a compound having a t-butyl substituted carbazole group is preferable.

《Electron transporting host》
The electron transporting host in the light emitting layer used in the present invention preferably has an electron affinity Ea of 2.5 eV or more and 3.5 eV or less from the viewpoint of improving durability and lowering driving voltage. More preferably, it is 0.4 eV or less, and further preferably 2.8 eV or more and 3.3 eV or less. Further, from the viewpoint of improving durability and reducing driving voltage, the ionization potential Ip is preferably 5.7 eV or more and 7.5 eV or less, more preferably 5.8 eV or more and 7.0 eV or less, and 5.9 eV or more. More preferably, it is 6.5 eV or less.

Specific examples of such an electron transporting host include the following materials.
Pyridine, pyrimidine, triazine, imidazole, pyrazole, triazole, oxazole, oxadiazol, fluorenone, anthraquinodimethane, anthrone, diphenylquinone, thiopyran dioxide, carbodiimide, fluorenylidenemethane, distyrylpyrazine, Fluorine-substituted aromatic compounds, heterocyclic tetracarboxylic anhydrides such as naphthaleneperylene, phthalocyanines, and derivatives thereof (may form condensed rings with other rings), metal complexes and metals of 8-quinolinol derivatives Examples thereof include various metal complexes represented by metal complexes having phthalocyanine, benzoxazole or benzothiazol as a ligand.

Preferred examples of the electron transporting host include metal complexes, azole derivatives (benzimidazole derivatives, imidazopyridine derivatives, etc.), and azine derivatives (pyridine derivatives, pyrimidine derivatives, triazine derivatives, etc.). To metal complex compounds are preferred. The metal complex compound (A) is more preferably a metal complex having a ligand having at least one nitrogen atom, oxygen atom or sulfur atom coordinated to the metal.
The metal ion in the metal complex is not particularly limited, but is preferably beryllium ion, magnesium ion, aluminum ion, gallium ion, zinc ion, indium ion, tin ion, platinum ion, or palladium ion, more preferably beryllium ion, Aluminum ion, gallium ion, zinc ion, platinum ion, or palladium ion, and more preferably aluminum ion, zinc ion, or palladium ion.

  There are various known ligands contained in the metal complex. For example, “Photochemistry and Photophysics of Coordination Compounds”, Springer-Verlag, H.C. Examples include the ligands described in Yersin, published in 1987, “Organometallic Chemistry: Fundamentals and Applications”, Sakai Hanafusa, Yamamoto Akio, published in 1982, and the like.

The ligand is preferably a nitrogen-containing heterocyclic ligand (preferably having 1 to 30 carbon atoms, more preferably 2 to 20 carbon atoms, particularly preferably 3 to 15 carbon atoms, and a monodentate ligand. Alternatively, it may be a bidentate or higher ligand, preferably a bidentate or higher and a hexadentate or lower ligand, or a bidentate or higher and lower 6 or lower ligand and a monodentate mixed ligand. preferable.
Examples of the ligand include an azine ligand (for example, pyridine ligand, bipyridyl ligand, terpyridine ligand, etc.), a hydroxyphenylazole ligand (for example, hydroxyphenylbenzimidazole coordination). And a hydroxyphenyl benzoxazole ligand, a hydroxyphenyl imidazole ligand, a hydroxyphenylimidazopyridine ligand, etc.), an alkoxy ligand (preferably having 1 to 30 carbon atoms, more preferably 1 carbon atom). To 20, particularly preferably 1 to 10 carbon atoms, such as methoxy, ethoxy, butoxy, 2-ethylhexyloxy), aryloxy ligands (preferably 6 to 30 carbon atoms, more preferably 6-20 carbon atoms, particularly preferably 6-12 carbon atoms, for example phenyl Carboxymethyl, 1-naphthyloxy, 2-naphthyloxy, 2,4,6-trimethylphenyl oxy, and 4-biphenyloxy and the like.),

Heteroaryloxy ligand (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, and examples thereof include pyridyloxy, pyrazyloxy, pyrimidyloxy, and quinolyloxy. ), An alkylthio ligand (preferably having 1 to 30 carbon atoms, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as methylthio and ethylthio), arylthio ligands (Preferably 6 to 30 carbon atoms, more preferably 6 to 20 carbon atoms, particularly preferably 6 to 12 carbon atoms, such as phenylthio), heteroarylthio ligand (preferably 1 carbon atom) To 30, more preferably 1 to 20 carbon atoms, particularly preferably 1 to 12 carbon atoms, such as pyridylthio , 2-benzimidazolylthio, 2-benzoxazolylthio, 2-benzthiazolylthio, etc.), a siloxy ligand (preferably having 1 to 30 carbon atoms, more preferably 3 to 25 carbon atoms). Particularly preferably, it has 6 to 20 carbon atoms, and examples thereof include a triphenylsiloxy group, a triethoxysiloxy group, and a triisopropylsiloxy group.), An aromatic hydrocarbon anion ligand (preferably having 6 carbon atoms) To 30, more preferably 6 to 25 carbon atoms, particularly preferably 6 to 20 carbon atoms, such as a phenyl anion, a naphthyl anion, an anthranyl anion, etc.), an aromatic heterocyclic anion ligand (preferably Has 1 to 30 carbon atoms, more preferably 2 to 25 carbon atoms, and particularly preferably 2 to 20 carbon atoms. Pyrrole anion, pyrazole anion, pyrazole anion, triazole anion, oxazole anion, benzoxazole anion, thiazole anion, benzothiazole anion, thiophene anion, benzothiophene anion, etc.), indolenine anion ligand, etc. , Preferably a nitrogen-containing heterocyclic ligand, aryloxy ligand, heteroaryloxy group, or siloxy ligand, more preferably a nitrogen-containing heterocyclic ligand, aryloxy ligand, siloxy coordination Or an aromatic hydrocarbon anion ligand or an aromatic heterocyclic anion ligand.

  Examples of the metal complex electron transporting host include, for example, patents such as Japanese Patent Application Laid-Open Nos. 2002-235076, 2004-214179, 2004-221106, 2004-220165, 2004-220168, and 2004-327313. Examples include compounds described in the publication.

  In the light emitting layer of the present invention, it is preferable in terms of color purity, light emission efficiency, and driving durability that the triplet lowest excitation level (T1) of the host material is higher than T1 of the phosphorescent light emitting material.

  Further, the content of the host compound in the present invention is not particularly limited, but from the viewpoint of light emission efficiency and driving voltage, it is 15% by mass to 95% by mass with respect to the total compound mass forming the light emitting layer. Preferably there is.

(Hole injection layer, hole transport layer)
The hole injection layer and the hole transport layer are layers having a function of receiving holes from the anode or the anode side and transporting them to the cathode side. The hole injection material and the hole transport material used for these layers may be a low molecular compound or a high molecular compound.
Specifically, pyrrole derivatives, carbazole derivatives, triazole derivatives, oxazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, styryl Anthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbene derivatives, silazane derivatives, aromatic tertiary amine compounds, styrylamine compounds, aromatic dimethylidin compounds, phthalocyanine compounds, porphyrin compounds, thiophene derivatives, organosilane derivatives, carbon, And the like.

  An electron-accepting dopant can be contained in the hole injection layer or the hole transport layer of the organic EL device of the present invention. As the electron-accepting dopant introduced into the hole-injecting layer or the hole-transporting layer, an inorganic compound or an organic compound can be used as long as it has an electron-accepting property and oxidizes an organic compound.

  Specifically, examples of the inorganic compound include metal halides such as ferric chloride, aluminum chloride, gallium chloride, indium chloride, and antimony pentachloride, metal oxides such as vanadium pentoxide, and molybdenum trioxide.

In the case of an organic compound, a compound having a nitro group, halogen, cyano group, trifluoromethyl group or the like as a substituent, a quinone compound, an acid anhydride compound, fullerene, or the like can be preferably used.
In addition, JP-A-6-212153, JP-A-11-111463, JP-A-11-251067, JP-A-2000-196140, JP-A-2000-286054, JP-A-2000-315580, JP-A-2001-102175, JP-A-2001-2001. -160493, JP2002-252085, JP2002-56985, JP2003-157981, JP2003-217862, JP2003-229278, JP2004-342614, JP2005-72012, JP20051666667 The compounds described in JP-A-2005-209643 and other patent publications can be suitably used.

  Among these, hexacyanobutadiene, hexacyanobenzene, tetracyanoethylene, tetracyanoquinodimethane, tetrafluorotetracyanoquinodimethane, p-fluoranyl, p-chloranil, p-bromanyl, p-benzoquinone, 2,6-dichlorobenzoquinone, 2 , 5-dichlorobenzoquinone, 1,2,4,5-tetracyanobenzene, 1,4-dicyanotetrafluorobenzene, 2,3-dichloro-5,6-dicyanobenzoquinone, p-dinitrobenzene, m-dinitrobenzene, o-dinitrobenzene, 1,4-naphthoquinone, 2,3-dichloronaphthoquinone, 1,3-dinitronaphthalene, 1,5-dinitronaphthalene, 9,10-anthraquinone, 1,3,6,8-tetranitrocarbazole, 2,4,7-trinitro-9- Luenone, 2,3,5,6-tetracyanopyridine or fullerene C60 is preferred, and hexacyanobutadiene, hexacyanobenzene, tetracyanoethylene, tetracyanoquinodimethane, tetrafluorotetracyanoquinodimethane, p-fluoranyl, p- Chloranil, p-bromanyl, 2,6-dichlorobenzoquinone, 2,5-dichlorobenzoquinone, 2,3-dichloronaphthoquinone, 1,2,4,5-tetracyanobenzene, 2,3-dichloro-5,6-dicyano Benzoquinone or 2,3,5,6-tetracyanopyridine is more preferred, and tetrafluorotetracyanoquinodimethane is particularly preferred.

These electron-accepting dopants may be used alone or in combination of two or more.
Although the usage-amount of an electron-accepting dopant changes with kinds of material, it is preferable that it is 0.01 mass%-50 mass% with respect to hole transport layer material, and it is 0.05 mass%-20 mass%. It is further more preferable and it is especially preferable that it is 0.1 mass%-10 mass%.

The thicknesses of the hole injection layer and the hole transport layer are each preferably 500 nm or less from the viewpoint of lowering the driving voltage.
The thickness of the hole transport layer is preferably 1 nm to 500 nm, more preferably 5 nm to 200 nm, and still more preferably 10 nm to 100 nm. In addition, the thickness of the hole injection layer is preferably 0.1 nm to 200 nm, more preferably 0.5 nm to 100 nm, and still more preferably 1 nm to 100 nm.
The hole injection layer and the hole transport layer may have a single-layer structure composed of one or more of the materials described above, or may have a multilayer structure composed of a plurality of layers having the same composition or different compositions. .

(Electron injection layer, electron transport layer)
The electron injection layer and the electron transport layer are layers having a function of receiving electrons from the cathode or the cathode side and transporting them to the anode side. The electron injection material and the electron transport material used for these layers may be a low molecular compound or a high molecular compound.
Specifically, pyridine derivatives, quinoline derivatives, pyrimidine derivatives, pyrazine derivatives, phthalazine derivatives, phenanthroline derivatives, triazine derivatives, triazole derivatives, oxazole derivatives, oxadiazole derivatives, imidazole derivatives, fluorenone derivatives, anthraquinodimethane derivatives, anthrone Derivatives, diphenylquinone derivatives, thiopyran dioxide derivatives, carbodiimide derivatives, fluorenylidenemethane derivatives, distyrylpyrazine derivatives, naphthalene, perylene and other aromatic ring tetracarboxylic acid anhydrides, phthalocyanine derivatives, 8-quinolinol derivative metal complexes, Metal phthalocyanines, various metal complexes represented by metal complexes with benzoxazole and benzothiazole as ligands, organosilane derivatives represented by siloles Body, or the like is preferably a layer containing.

The electron injection layer or the electron transport layer of the organic EL device of the present invention can contain an electron donating dopant. The electron donating dopant introduced into the electron injecting layer or the electron transporting layer only needs to have an electron donating property and a property of reducing an organic compound, such as an alkali metal such as Li or an alkaline earth metal such as Mg. Transition metals including rare earth metals and reducing organic compounds are preferably used. As the metal, a metal having a work function of 4.2 eV or less can be preferably used. Specifically, Li, Na, K, Be, Mg, Ca, Sr, Ba, Y, Cs, La, Sm, Gd , And Yb. Examples of the reducing organic compound include nitrogen-containing compounds, sulfur-containing compounds, and phosphorus-containing compounds.
In addition, the materials described in JP-A-6-212153, JP-A-2000-196140, JP-A-2003-68468, JP-A-2003-229278, JP-A-2004-342614, and the like can be used.

These electron donating dopants may be used alone or in combination of two or more.
Although the usage-amount of an electron donating dopant changes with kinds of material, it is preferable that it is 0.1 mass%-99 mass% with respect to electron transport layer material, and it is 1.0 mass%-80 mass%. Is more preferable, and 2.0 mass% to 70 mass% is particularly preferable.

The thicknesses of the electron injection layer and the electron transport layer are each preferably 500 nm or less from the viewpoint of lowering the driving voltage.
The thickness of the electron transport layer is preferably 1 nm to 500 nm, more preferably 5 nm to 200 nm, and still more preferably 10 nm to 100 nm. In addition, the thickness of the electron injection layer is preferably 0.1 nm to 200 nm, more preferably 0.2 nm to 100 nm, and still more preferably 0.5 nm to 50 nm.
The electron injection layer and the electron transport layer may have a single layer structure composed of one or more of the above-described materials, or may have a multilayer structure composed of a plurality of layers having the same composition or different compositions.

(Hole blocking layer)
The hole blocking layer is a layer having a function of preventing holes transported from the anode side to the light emitting layer from passing through to the cathode side. In the present invention, a hole blocking layer can be provided as an organic compound layer adjacent to the light emitting layer on the cathode side.
Examples of the compound constituting the hole blocking layer include aluminum complexes such as BAlq, triazole derivatives, phenanthroline derivatives such as BCP, and the like.
The thickness of the hole blocking layer is preferably 1 nm to 500 nm, more preferably 5 nm to 200 nm, and still more preferably 10 nm to 100 nm.
The hole blocking layer may have a single layer structure composed of one or more of the above-described materials, or may have a multilayer structure composed of a plurality of layers having the same composition or different compositions.

(Electronic block layer)
The electron blocking layer is a layer having a function of preventing electrons transported from the cathode side to the light emitting layer from passing through to the anode side. In the present invention, an electron blocking layer can be provided as the organic compound layer adjacent to the light emitting layer on the anode side.
As examples of the compound constituting the electron blocking layer, for example, those mentioned as the hole transport material described above can be applied.
The thickness of the electron blocking layer is preferably 1 nm to 500 nm, more preferably 5 nm to 200 nm, and even more preferably 10 nm to 100 nm.
The hole blocking layer may have a single layer structure composed of one or more of the above-described materials, or may have a multilayer structure composed of a plurality of layers having the same composition or different compositions.
(Protective layer)
In the present invention, the entire organic EL element may be protected by a protective layer.
As a material contained in the protective layer, any material may be used as long as it has a function of preventing materials that promote device deterioration such as moisture and oxygen from entering the device.
Specific examples thereof include metals such as In, Sn, Pb, Au, Cu, Ag, Al, Ti, and Ni, MgO, SiO, SiO ₂ , Al ₂ O ₃ , GeO, NiO, CaO, BaO, and Fe ₂ O. ₃ , metal oxides such as Y ₂ O ₃ , TiO ₂ , metal nitrides such as SiN _x , SiN _x O _y , metal fluorides such as MgF ₂ , LiF, AlF ₃ , CaF ₂ , polyethylene, polypropylene, polymethyl Monomer mixture containing methacrylate, polyimide, polyurea, polytetrafluoroethylene, polychlorotrifluoroethylene, polydichlorodifluoroethylene, copolymer of chlorotrifluoroethylene and dichlorodifluoroethylene, tetrafluoroethylene and at least one comonomer Copolymer obtained by copolymerization, cyclic in the copolymer main chain Examples thereof include a fluorine-containing copolymer having a structure, a water-absorbing substance having a water absorption of 1% or more, and a moisture-proof substance having a water absorption of 0.1% or less.

  The method for forming the protective layer is not particularly limited. For example, vacuum deposition, sputtering, reactive sputtering, MBE (molecular beam epitaxy), cluster ion beam, ion plating, plasma polymerization (high frequency) Excited ion plating method), plasma CVD method, laser CVD method, thermal CVD method, gas source CVD method, coating method, printing method, transfer method can be applied.

(Sealing)
Furthermore, the organic electroluminescent element of this invention may seal the whole element using a sealing container.
Further, a moisture absorbent or an inert liquid may be sealed in a space between the sealing container and the light emitting element. Although it does not specifically limit as a moisture absorber, For example, barium oxide, sodium oxide, potassium oxide, calcium oxide, sodium sulfate, calcium sulfate, magnesium sulfate, phosphorus pentoxide, calcium chloride, magnesium chloride, copper chloride Cesium fluoride, niobium fluoride, calcium bromide, vanadium bromide, molecular sieve, zeolite, magnesium oxide, and the like. The inert liquid is not particularly limited, and examples thereof include paraffins, liquid paraffins, fluorinated solvents such as perfluoroalkane, perfluoroamine, and perfluoroether, chlorinated solvents, and silicone oils. Can be mentioned.

Moreover, the method of sealing with the resin sealing layer shown below is also used suitably.
(Resin sealing layer)
The functional element of the present invention preferably suppresses deterioration of element performance due to oxygen or moisture by contact with the atmosphere by the resin sealing layer.
<Material>
The resin material for the resin sealing layer is not particularly limited, and an acrylic resin, an epoxy resin, a fluorine resin, a silicon resin, a rubber resin, an ester resin, or the like can be used. An epoxy resin is preferable from the viewpoint of the prevention function. Among the epoxy resins, a thermosetting epoxy resin or a photocurable epoxy resin is preferable.
<Production method>
The method for producing the resin sealing layer is not particularly limited, and examples thereof include a method of applying a resin solution, a method of pressure bonding or thermocompression bonding of a resin sheet, and a method of dry polymerization by vapor deposition or sputtering.
<Film thickness>
The thickness of the resin sealing layer is preferably 1 μm or more and 1 mm or less. More preferably, they are 5 micrometers or more and 100 micrometers or less, Most preferably, they are 10 micrometers or more and 50 micrometers or less. If it is thinner than this, the inorganic film may be damaged when the second substrate is mounted. On the other hand, if it is thicker than this, the thickness of the electroluminescent element itself is increased, and the thin film property that is characteristic of the organic electroluminescent element is impaired.

(Sealing adhesive)
The sealing adhesive used in the present invention has a function of preventing intrusion of moisture and oxygen from the end portion.
<Material>
As the material of the sealing adhesive, the same material as that used for the resin sealing layer can be used. Among these, epoxy adhesives are preferable from the viewpoint of moisture prevention, and among them, a photocurable adhesive or a thermosetting adhesive is preferable.

It is also preferable to add a filler to the above material.
The filler added to the sealant is preferably an inorganic material such as SiO ₂ , SiO (silicon oxide), SiON (silicon oxynitride) or SiN (silicon nitride). Addition of the filler increases the viscosity of the sealant, improves processing suitability, and improves moisture resistance.

<Drying agent>
The sealing adhesive may contain a desiccant. As the desiccant, barium oxide, calcium oxide, or strontium oxide is preferable.
The amount of the desiccant added to the sealing adhesive is preferably 0.01% by mass or more and 20% by mass or less, and more preferably 0.05% by mass or more and 15% by mass or less. If it is less than this, the effect of adding the desiccant will be reduced. On the other hand, when it is more than this, it becomes difficult to uniformly disperse the desiccant in the sealing adhesive, which is not preferable.
<Prescription of sealing adhesive>
-Polymer composition, density | concentration It does not specifically limit as a sealing adhesive agent, The said thing can be used. For example, XNR5516 manufactured by Nagase Chemtech Co., Ltd. can be cited as a photo-curable epoxy adhesive. What is necessary is just to add and disperse | distribute the said desiccant directly there.
-Thickness The coating thickness of the sealing adhesive is preferably 1 μm or more and 1 mm or less. If it is thinner than this, the sealing adhesive cannot be applied uniformly, which is not preferable. On the other hand, if it is thicker than this, the route through which moisture invades becomes wide, which is not preferable.
<Sealing method>
In the present invention, a functional element can be obtained by applying an arbitrary amount of the sealing adhesive containing the desiccant with a dispenser or the like, and stacking and curing the second substrate after application.

(Drive)
The organic electroluminescence device of the present invention emits light by applying a direct current (which may include an alternating current component as necessary) voltage (usually 2 to 15 volts) or a direct current between the anode and the cathode. Obtainable.
The driving method of the organic electroluminescent device of the present invention is described in JP-A-2-148687, JP-A-6-301355, JP-A-5-29080, JP-A-7-134558, JP-A-8-234658, and JP-A-8-2441047. The driving methods described in each publication, Japanese Patent No. 2784615, US Pat. Nos. 5,828,429, 6023308, and the like can be applied.

  The light-emitting element of the present invention can improve the light extraction efficiency by various known devices. For example, by processing the substrate surface shape (for example, forming a fine concavo-convex pattern), controlling the refractive index of the substrate / ITO layer / organic layer, controlling the film thickness of the substrate / ITO layer / organic layer, etc. It is possible to improve light extraction efficiency and external quantum efficiency.

  The light-emitting element of the present invention may be a so-called top emission type in which light emission is extracted from the anode side.

The organic EL device of the present invention can have a structure in which a charge generation layer is provided between a plurality of light emitting layers in order to improve luminous efficiency.
The charge generation layer is a layer having a function of generating charges (holes and electrons) when an electric field is applied and a function of injecting the generated charges into a layer adjacent to the charge generation layer.

The material for forming the charge generation layer may be any material having the above functions, and may be formed of a single compound or a plurality of compounds.
Specifically, it may be a conductive material, a semiconductive material such as a doped organic layer, or an electrically insulating material. Examples thereof include materials described in patent publications such as 11-329748, JP-A No. 2003-272860, and JP-A No. 2004-39617.
More specifically, transparent conductive materials such as ITO and IZO (indium zinc oxide), fullerenes such as C60, conductive organic materials such as oligothiophene, metal phthalocyanines, metal-free phthalocyanines, metal porphyrins, metal-free Conductive organic materials such as porphyrins, metal materials such as Ca, Ag, Al, Mg: Ag alloy, Al: Li alloy, Mg: Li alloy, hole conductive material, electron conductive material, and a mixture thereof May be used.
The hole conductive material is, for example, a material in which a hole transporting organic material such as 2-TNATA or NPD is doped with an oxidant having an electron withdrawing property such as F4-TCNQ, TCNQ, or FeCl ₃ , or a P-type conductive material. The electron conductive material includes an electron transporting organic material doped with a metal or a metal compound having a work function of less than 4.0 eV, an N type conductive polymer, N type Type semiconductors. Examples of the N-type semiconductor include N-type Si, N-type CdS, and N-type ZnS. Examples of the P-type semiconductor include P-type Si, P-type CdTe, and P-type CuO.
Further, an electrically insulating material such as V ₂ O ₅ can be used for the charge generation layer.

  The charge generation layer may be a single layer or a stack of a plurality of layers. A structure in which a plurality of layers are stacked includes a conductive material such as a transparent conductive material and a metal material and a hole conductive material, or a structure in which an electron conductive material is stacked, and the above hole conductive material and electron conductive And a layer having a structure in which a functional material is laminated.

In general, it is preferable to select a film thickness and a material for the charge generation layer so that the visible light transmittance is 50% or more. The film thickness is not particularly limited, but is preferably 0.5 nm to 200 nm, more preferably 1 nm to 100 nm, still more preferably 3 nm to 50 nm, and particularly preferably 5 nm to 30 nm.
The method for forming the charge generation layer is not particularly limited, and the above-described method for forming the organic compound layer can be used.

The charge generation layer is formed between the two or more light emitting layers. The charge generation layer may include a material having a function of injecting charges into adjacent layers on the anode side and the cathode side. In order to improve the electron injection property to the layer adjacent to the anode side, for example, an electron injection compound such as BaO, SrO, Li ₂ O, LiCl, LiF, MgF ₂ , MgO, and CaF _{2 is} added to the anode side of the charge generation layer. May be laminated.
In addition to the above-mentioned contents, the charge generation layer material can be selected based on the descriptions in Japanese Patent Application Laid-Open No. 2003-45676, U.S. Pat. You can choose.

The organic EL element in the present invention may have a resonator structure. For example, a multilayer mirror made of a plurality of laminated films having different refractive indexes, a transparent or translucent electrode, a light emitting layer, and a metal electrode are superimposed on a transparent substrate. The light generated in the light emitting layer resonates repeatedly with the multilayer mirror and the metal electrode as a reflection plate.
In another preferred embodiment, a transparent or translucent electrode and a metal electrode each function as a reflector on a transparent substrate, and light generated in the light emitting layer repeats reflection and resonates between them.
In order to form a resonant structure, the optical path length determined from the effective refractive index of the two reflectors and the refractive index and thickness of each layer between the reflectors is adjusted to the optimum value to obtain the desired resonant wavelength. Is done. The calculation formula in the case of the first embodiment is described in JP-A-9-180883. The calculation formula in the case of the second aspect is described in JP-A-2004-127795.

For example, as described in “Monthly Display”, September 2000, pages 33 to 37, a method for making an organic EL display of a full color type includes three primary colors (blue (B) and green). (G), red light (R)), a three-color light emitting method in which organic EL elements that emit light corresponding to red (R) are arranged on a substrate, and white light emitted by a white light emitting organic EL element into three primary colors through a color filter. And a color conversion method in which blue light emission by an organic EL element for blue light emission is converted into red (R) and green (G) through a fluorescent dye layer are known.
Moreover, the planar light source of a desired luminescent color can be obtained by using combining the organic EL element of the different luminescent color obtained by the said method. For example, a white light-emitting light source that combines blue and yellow light-emitting elements, a white light-emitting light source that combines blue, green, and red light-emitting elements.

4). Pixel Circuit Configuration of Organic EL Display Device FIG. 5 is a schematic diagram of a pixel circuit of an active matrix organic EL display device using TFT elements used in the present invention. The circuit of the display device in the present invention is not particularly limited to that shown in FIG. 5, and a conventionally known circuit can be applied as it is.
(application)
The organic EL display device of the present invention is applied in a wide range of fields including a mobile phone display, a personal digital assistant (PDA), a computer display, an automobile information display, a TV monitor, or general lighting.

  Hereinafter, the organic EL display device of the present invention will be described with reference to examples, but the present invention is not limited to these examples.

Example 1
1. 1. Production of organic EL display device 1-1. Production of Organic EL Display Device 1 An organic EL display device having the configuration shown in FIG. 1 was produced.

(Preparation of organic EL element part)
1) Formation of lower electrode Indium tin oxide (hereinafter abbreviated as ITO) was vapor-deposited on a glass substrate (Corning, product number: No. 1737) to a thickness of 150 nm to form an anode.

2) Formation of organic layer After washing, a hole injection layer, a hole transport layer, a light emitting layer, a hole blocking layer, an electron transport layer, and an electron injection layer were sequentially provided.

The configuration of each layer is as follows. Each layer was provided by resistance heating vacuum deposition.
Hole injection layer: 4,4 ′, 4 ″ -tris (2-naphthylphenylamino) triphenylamine (abbreviated as 2-TNATA) and 2,3,5,6-tetrafluoro-7,7,8 , 8-tetracyanoquinodimethane (abbreviated as F4-TCNQ), containing 1% by mass with respect to 2-TNATA, thickness 160 nm.
Hole transport layer: N, N′-dinaphthyl-N, N′-diphenyl- [1,1′-biphenyl] -4,4′-diamine (abbreviated as α-NPD), thickness 10 nm.
Light-emitting layer: a layer containing 13% by mass of 1,3-bis (carbazol-9-yl) benzone (abbreviated as mCP) and platinum complex Pt-1 with respect to mCP, thickness 60 nm.
Hole blocking layer: bis- (2-methyl-8-quinolinylphenolate) aluminum (abbreviated as BAlq), thickness 40 nm.
Electron transport layer: Tris (8-hydroxyquinolinate) aluminum (abbreviated as Alq3), thickness 10 nm.
Electron injection layer: LiF, thickness 1 nm.

3) Upper electrode It patterned by the shadow mask so that element size might be set to 1 mm x 1 mm, and Al was vapor-deposited in thickness of 100 nm, and it was set as the cathode.

  The structures of the compounds used in the examples are shown below.

(Conductive etching protective film)
A 150 nm SnO ₂ film was formed on the upper electrode as a conductive etching protective film by RF magnetron sputtering. Patterning was performed using a shadow mask, and a 0.5 mm × 0.5 mm conductive etching protective film was formed on the cathode Al.

(Protective insulating film)
A 500 nm SiON film was formed as a protective insulating film by an ion plating method.
(Contact hole formation)
A resist was applied on the protective insulating film, and mask exposure was performed to form a resist at a place other than the place where the contact hole was formed.
After forming the resist, the protective insulating film was etched using buffered hydrofluoric acid to form contact holes. Thereafter, the resist was removed.

(Production of TFT part)
1) Source electrode and drain electrode As a source electrode and a drain electrode, Mo was deposited to a thickness of 40 nm and ITO to a thickness of 40 nm by RF magnetron sputtering. A lift-off method was used for patterning the source electrode and the drain electrode. At this time, the gap between the source and drain electrodes was formed so that the channel length (L) = 50 μm and the channel width (W) = 250 μm. The conductive etching protective film connected to the upper electrode (cathode) of the organic EL element and the drain electrode are electrically connected via a contact hole.

2) Active layer Using a polycrystalline sintered body having a composition of InGaZnO ₄ as a target, an IGZO deposited layer having a thickness of 50 nm was provided by RF magnetron sputtering vacuum deposition. The electric conductivity of the active layer was 5.7 × 10 ⁻³ Scm ⁻¹ . A shadow mask was used for patterning.

3) Gate insulating film SiO ₂ was formed to 200 nm by RF magnetron sputtering vacuum deposition, and a gate insulating film was provided. A shadow mask was used for patterning.
4) Gate electrode A deposited layer of Mo having a thickness of 100 nm was formed. Photolitho etching was used for patterning.

1-2. Production of Comparative Organic EL Display Device A A comparative organic EL display device A was produced in the same manner as in the organic EL display device 1 except for the conductive etching protective film.

1-3. Production of Organic EL Display Device B In the organic EL display device 1 of Example 1, the active layer of the TFT was changed to pentacene, which is an organic semiconductor, and evaporated to a thickness of 50 nm. Other than that was carried out similarly to the organic EL display apparatus 1, and produced the organic EL display apparatus B. FIG.

2. Performance Evaluation In the obtained organic EL display device 1 and the comparative organic EL display device A, the gate voltage and source / drain voltage of the driving TFT were adjusted so that a current of 1.0 mA / cm ² would flow in the organic EL element portion. As a result, the organic EL display device 1 and the comparative organic EL display device A exhibited good blue light emission. In the organic EL display device 1, an emission luminance of 160 cd / m ² was obtained, but the comparative organic EL display device A Then, only an emission luminance of 85 cd / m ² was obtained. In the organic EL display device B, a light emission luminance of 150 cd / m ² and equivalent to that of the organic EL display device 1 was obtained.

Example 2
1. Production of Organic EL Display Device 2 In the organic EL display device 1 of Example 1, the active layer was changed to the following two-layer configuration of an active layer and a resistance layer. A layer near the source electrode and the drain electrode was a resistance layer, and a layer near the gate insulating film was an active layer. Otherwise, the organic EL display device 2 of the present invention was produced in the same manner as the organic EL display device 1 of Example 1.
Resistance layer: IGZO was deposited to a thickness of 40 nm by RF magnetron sputtering vacuum deposition. The electric conductivity was 1.0 × 10 ⁻⁴ Scm ⁻¹ by adjusting the Ar flow rate and the O ₂ flow rate.
Active layer: IGZO was deposited to 10 nm by RF magnetron sputtering vacuum deposition. The electric conductivity was 2.6 × 10 ⁻¹ Scm ⁻¹ by adjusting the Ar flow rate and the O ₂ flow rate.

2. Performance Evaluation As in Example 1, when the gate voltage and source / drain voltage of the driving TFT are adjusted so that a current of 1.0 mA / cm ² flows in the organic EL element part, the organic EL display device 2 is an organic EL display. As with the display device 1, an emission luminance of 160 cd / m ² was obtained. 14V to the gate electrode of the driving TFT, when the 20V applied to the anode of the organic EL element, emission luminance is 230cd / ^{m 2,} shows a brightness unexpectedly high than 175cd / ^{m 2} of the organic EL display device 1 It was.

Example 3
1. Production of Organic EL Display Device 3 In the organic EL display device 2 of Example 2, the glass substrate is changed to a PEN substrate having a SiON thickness of 40 nm on both sides as a barrier layer, and the others are the same as the organic EL display device 2 in the present invention. The organic EL display device 3 was produced.

2. Performance Evaluation When the gate voltage and source / drain voltage of the driving TFT are adjusted so that a current of 1.0 mA / cm ² flows in the organic EL element part, the organic EL display device 3 obtains an emission luminance of 150 cd / m ^2. It was. Further, when 14V is applied to the gate electrode of the driving TFT and 20V is applied to the anode of the organic EL element, the light emission luminance is 210 cd / m ² , and the same light emission luminance as that of the organic EL display device 2 is obtained even on the flexible substrate. .

Example 4
1. Production of Organic EL Display Devices 4 to 6 In the organic EL display devices 1 to 3 in Examples 1 to 3, the conductive etching protective film was changed to the following to produce organic EL display devices 4 to 6, respectively.
(Conductive etching protective film)
An ITO film with a thickness of 150 nm was formed by an ion plating method as a conductive etching protective film. Patterning was performed using a shadow mask, and a 0.5 mm × 0.5 mm conductive etching protective film was formed on the cathode Al.

2. Performance Evaluation When the gate voltage and source / drain voltage of the driving TFT are adjusted so that a current of 1.0 mA / cm ² flows in the organic EL element part, both the organic EL display device 4 and the organic EL display device 5 are 150 cd / An emission luminance of m ² was obtained. In addition, in the organic EL display device 6, a light emission luminance of 130 cd / m ² was obtained. These showed higher luminance than the organic EL display device A of the comparative example.

It is a schematic diagram which shows the structure of the organic electroluminescent display apparatus of this invention. It is a schematic diagram which shows the structure of a comparative organic electroluminescence display. It is a schematic diagram which shows the structure of TFT used for this invention. It is a schematic diagram which shows the structure of TFT of another aspect used for this invention. It is a schematic diagram of the pixel circuit of the organic EL display device of the present invention.

Explanation of symbols

1, 11, 100, 110: Substrate 6, 16: Insulating layers 2, 12, 102, 112: Gate electrodes 3, 13, 103, 113: Gate insulating films 4, 104, 114: Active layers 4-2, 4- 12: resistance layers 4-1, 4-11: active layers 5-1, 5-11, 105a, 115a: source electrodes 5-2, 5-12, 105b, 115b: drain electrodes 30, 40: lower electrode 32, 42: Organic layer 34, 44: Upper electrode 106, 116: Protective insulating film 36, 46: Insulating film 108, 118: Contact hole 109: Conductive etching protective film

Claims (28)

  An organic EL device in which at least a lower electrode, an organic layer including at least a light emitting layer, and an upper electrode are sequentially formed on a substrate, and a thin film field effect transistor for driving the organic EL device formed on the organic EL device An organic EL display device having a conductive etching protective film in electrical contact with the upper electrode between the upper electrode and the thin film field effect transistor, the conductive etching protective film and the thin film A protective insulating film is provided between the field effect transistor and the source or drain electrode of the thin film field effect transistor and the conductive etching protective film are electrically connected through a contact hole provided in the protective insulating film. An organic EL display device.   The contact hole is formed by etching with an etching material, and the etching rate of the conductive etching protective film is slower than the etching rate of the upper electrode by the etching material. The organic EL display device described.   The contact hole is formed by etching with an etching material, and the etching rate of the conductive etching protective film is slower than the etching rate of the protective insulating film with the etching material. Alternatively, an organic EL display device according to claim 2.   The upper electrode is formed by a resistance heating vapor deposition method, and the conductive etching protective film is formed by a sputtering method, an ion plating method, or a Chemical Vapor Deposition method (CVD method). The organic EL display device according to any one of claims 1 to 3.   The organic EL display according to any one of claims 1 to 4, wherein the active layer of the thin film field effect transistor contains an oxide semiconductor, an organic semiconductor, or a carbon nanotube as a semiconductor material. apparatus.   6. The organic EL display device according to claim 5, wherein the active layer of the thin film field effect transistor includes an oxide semiconductor.   The organic EL display device according to claim 6, wherein the oxide semiconductor is an amorphous oxide semiconductor.   The organic EL display device according to claim 1, wherein the lower electrode is a light transmissive electrode.   The organic EL display device according to claim 8, wherein the upper electrode is a light reflective electrode.   The organic EL display device according to any one of claims 1 to 9, wherein the lower electrode is an anode, and the upper electrode is a cathode.   The organic EL display device according to claim 10, wherein the thin film field effect transistor has an N-type polarity.   12. The resistance layer according to claim 1, wherein a resistance layer is electrically connected between the active layer and at least one of the source electrode and the drain electrode. Organic EL display device.   13. The resistance layer and the active layer are formed in layers, the active layer is in contact with the gate insulating film, and the resistance layer is in contact with at least one of the source electrode and the drain electrode. The organic EL display device described in 1.   The organic EL display device according to claim 13, wherein the thickness of the resistance layer is larger than the thickness of the active layer.   15. The organic EL display device according to claim 12, wherein electrical conductivity between the resistance layer and the active layer continuously changes.   The organic EL display device according to claim 12, wherein the active layer and the resistance layer include an oxide semiconductor.   The organic EL display device according to claim 16, wherein the oxide semiconductor includes at least one selected from the group consisting of In, Ga, and Zn, or a composite oxide thereof.   The oxide semiconductor contains In and Zn, and the composition ratio of Zn and In of the resistance layer (the ratio of Zn to In, Zn / In) is larger than the composition ratio Zn / In of the active layer, The organic EL display device according to claim 17.   The organic EL display device according to claim 16, wherein an oxygen concentration of the active layer is lower than an oxygen concentration of the resistance layer. 20. The organic EL display device according to claim 12, wherein the active layer has an electric conductivity of 10 ⁻⁴ Scm ⁻¹ or more and less than 10 ² Scm ⁻¹ . The organic EL display device according to claim 20, wherein the electric conductivity of the active layer is 10 ^-1 Scm ^-1 or more and less than 10 ² Scm ^-1 . The ratio of the electrical conductivity of the active layer to the electrical conductivity of the resistive layer (the electrical conductivity of the active layer / the electrical conductivity of the resistive layer) is 10 ¹ or more and 10 ¹⁰ or less. The organic EL display device according to claim 21. 23. The ratio of the electrical conductivity of the active layer to the electrical conductivity of the resistive layer (the electrical conductivity of the active layer / the electrical conductivity of the resistive layer) is 10 ² or more and 10 ⁸ or less. The organic EL display device described in 1.   The organic EL display device according to any one of claims 1 to 23, wherein the substrate is a flexible resin substrate.   25. The method of manufacturing an organic EL display device according to claim 1, wherein at least a lower electrode, at least an organic layer including at least a light emitting layer, and an upper electrode are sequentially formed on a substrate. A step of forming an organic EL element portion, a step of forming a conductive etching protective film in electrical contact with the upper electrode, a step of forming a protective insulating film on the conductive etching protective film, and an etching material A method for manufacturing an organic EL display device, comprising: forming a contact hole in the protective insulating film; and forming a thin film field effect transistor on the protective insulating film, wherein the source of the thin film field effect transistor or A drain electrode and the conductive etching protective film are electrically connected through the contact hole. A method of manufacturing an organic EL display device.   26. The method of manufacturing an organic EL display device according to claim 25, wherein an etching rate of the conductive etching protective film is slower than an etching rate of the upper electrode by the etching material.   27. The method of manufacturing an organic EL display device according to claim 25, wherein an etching rate of the conductive etching protective film is slower than an etching rate of the protective insulating film by the etching material.   The upper electrode is formed by a resistance heating vapor deposition method, and the conductive etching protection film is formed by a sputtering method, an ion plating method, or a chemical vapor deposition method (CVD) method. 27. A method for producing an organic EL display device according to any one of 27.