WO2014196329A1

WO2014196329A1 - Organic electroluminescence element

Info

Publication number: WO2014196329A1
Application number: PCT/JP2014/062915
Authority: WO
Inventors: 宏石代
Original assignee: コニカミノルタ株式会社
Priority date: 2013-06-06
Filing date: 2014-05-15
Publication date: 2014-12-11
Also published as: JPWO2014196329A1

Abstract

The purpose of the present invention is to provide a flexible, light-weight organic electroluminescence element which has a flexible substrate using a metal layer or a metal foil and having excellent gas barrier properties, which improves light extraction efficiency by suppressing the occurrence of plasmon loss of the light resulting from specular reflection on the substrate and a metal electrode, and which reduces color shift by suppressing the cavity effect at specific wavelengths by utilizing diffuse reflection. This organic electroluminescence element is characterized in that a functional layer that includes at least a white pigment, a first transparent electrode, an organic light-emitting layer, a second transparent electrode, and a transparent sealing substrate are arranged in that order on a flexible substrate on which a metal layer or metal foil is laminated.

Description

Organic electroluminescence device

The present invention relates to an organic electroluminescence element. More specifically, the present invention relates to a flexible and lightweight organic electroluminescence element that has high light extraction efficiency and reduced color shift.

Currently, organic light emitting devices are attracting attention as thin light emitting materials.

Organic light-emitting devices (hereinafter also referred to as organic EL devices) using organic electroluminescence (EL) are thin-film, completely solid-state devices that can emit light at a low voltage of several volts to several tens of volts. It has many excellent features such as high brightness, high luminous efficiency, thinness, and light weight. For this reason, it has been attracting attention in recent years as surface light emitters such as backlights for various displays, display boards such as signboards and emergency lights, and illumination light sources.

Such an organic EL element has a configuration in which a light emitting layer made of an organic material is disposed between two electrodes, and emitted light generated in the light emitting layer passes through the electrode and is extracted outside. Therefore, at least one of the two electrodes is configured as a transparent electrode, and emitted light is extracted from the transparent electrode side.

Also, organic light-emitting elements are characterized by thin-film surface light emission different from conventional light emitters, and element formation on a flexible transparent substrate is desired to take advantage of these characteristics. In response to such a demand, there is a great demand for an organic EL element using a general-purpose resin base material such as a polyethylene terephthalate (PET) film widely used in the market as a film substrate of transparent plastic or the like.

However, a film substrate such as a transparent plastic has a problem that the gas barrier property is inferior to that of a glass substrate. If a substrate with inferior gas barrier properties is used, water vapor and oxygen will permeate, and for example, the function in the electronic device will be degraded.

As a substrate having both gas barrier properties and flexibility, Patent Document 1 includes a plastic substrate coated with a metal layer or a metal foil, a substrate having a metal layer sandwiched between two plastic layers, and a metal foil. Although a certain substrate is disclosed, for example, the surface of the metal foil has fine irregularities on the surface of the metal foil manufacturing process, and when an electrode and an organic light emitting layer are formed on the upper layer, the organic EL element There is a problem that short-circuiting (electrical short-circuiting) easily occurs with storage over time.

Furthermore, when a substrate having a metal layer or a metal foil and a metal electrode are used, the light emitted from the organic light emitting layer is specularly reflected to generate a plasmon mode, which is a kind of waveguide mode, and the surface of the reflector. There is a problem that “plasmon loss”, which is a loss of light confined in the vicinity, easily occurs, and the light extraction efficiency decreases. There is also a problem that a cavity effect is generated, and the viewing angle dependency of emission chromaticity is deteriorated.

In Patent Document 2, by forming a layer such as a carbon black-based thin film on a substrate, reflection of light emitted from the organic light emitting layer is prevented, and optical interference caused by emitted light and reflected light is suppressed. Although a technique for preventing color misregistration is disclosed, there is a problem in that light emission luminance is reduced due to light absorption of the carbon black thin film.

Special Table 2007-536697 JP 2010-177093 A

The present invention has been made in view of the above problems and situations, and a solution to the problem is to provide a flexible substrate having a high gas barrier property using a metal layer or a metal foil, and the substrate and the metal electrode. Flexibility that improves light extraction efficiency by suppressing the occurrence of plasmon loss of light due to specular light reflection, and reduces color shift by suppressing the cavity effect of a specific wavelength by using light diffusion reflection It is providing the organic electroluminescent element which has the property and is lightweight.

In order to solve the above-mentioned problems, the present inventor has a high gas barrier property by an organic electroluminescence element having a specific functional layer on a specific flexible substrate in the process of examining the cause of the above-mentioned problem. The present inventors have found that a light-emitting organic electroluminescence element having high light extraction efficiency and reduced color misregistration can be provided.

That is, the above-mentioned problem according to the present invention is solved by the following means.

1. Having a functional layer containing at least a white pigment, a first transparent electrode, an organic light emitting layer, a second transparent electrode, and a transparent sealing substrate in this order on a flexible substrate on which a metal layer or a metal foil is laminated An organic electroluminescence device characterized by the above.

2. 2. The organic electroluminescence device according to claim 1, further comprising a smooth layer between the functional layer containing the white pigment and the first transparent electrode.

3. Either the first transparent electrode or the second transparent electrode contains silver or an alloy containing silver as a main component, or the organic electroluminescent element according to the first or second item.

4. The first transparent electrode has an underlayer containing an organic compound having at least one atom selected from a nitrogen atom and a sulfur atom on the flexible substrate side of the first transparent electrode. The organic electroluminescent element as described in any one of the items to.

5. The organic electroluminescence device according to any one of items 1 to 4, further comprising an electrode protective layer on the second transparent electrode.

6. 6. The organic electroluminescence device according to item 5, wherein the electrode protective layer contains a metal oxide.

By the above means of the present invention, a flexible substrate having a high gas barrier property using a metal layer or a metal foil is provided, and generation of plasmon loss of light due to specular light reflection of the substrate and the metal electrode is suppressed. It is possible to provide a flexible and lightweight organic electroluminescent element that improves light extraction efficiency and suppresses a color shift by suppressing a cavity effect of a specific wavelength by utilizing light diffuse reflection. it can.

The expression mechanism or action mechanism of the effect of the present invention is not clear, but is presumed as follows.

The organic electroluminescent element of the present invention can achieve both high gas barrier properties and flexibility by using a flexible substrate on which a metal layer or a metal foil is laminated. Light emission generated on a metal reflective electrode formed on a substrate, such as a normal top-emitting element, by arranging a white light diffusing reflective layer containing a white pigment as a functional layer between the first transparent electrodes It is presumed that the coupling of the light to the plasmon mode can be suppressed by the white light diffuse reflection, and the light extraction efficiency is improved.

Further, by utilizing the white light diffuse reflection, the cavity effect at a specific wavelength can be suppressed, so that it is presumed that an organic electroluminescence element with reduced color shift can be obtained.

Schematic diagram of a flexible substrate according to the present invention Schematic diagram of a flexible substrate according to the present invention The schematic diagram which shows an example of a structure of the organic EL element of this invention The schematic diagram which shows an example of the vacuum ultraviolet irradiation apparatus used for formation of the smooth layer based on this invention

The organic electroluminescent element of the present invention has a functional layer containing at least a white pigment, a first transparent electrode, an organic light emitting layer, a second transparent electrode on a flexible substrate in which a metal layer or a metal foil is laminated, And having a transparent sealing substrate in this order. This feature is a technical feature common to the inventions according to claims 1 to 6.

As an embodiment of the present invention, it is preferable to have a smooth layer between the functional layer containing the white pigment and the first transparent electrode, from the viewpoint of manifesting the effect of the present invention. By smoothing the surface of the layer, it is possible to suppress the occurrence of a short circuit (electrical short circuit) or the like associated with storage over time of the transparent electrode formed on the functional layer.

Further, either the first transparent electrode or the second transparent electrode contains silver or an alloy containing silver as a main component, and a nitrogen atom and a sulfur atom are formed on the flexible substrate side of the first transparent electrode. It is preferable to have a base layer containing an organic compound having at least one kind of atom selected from the viewpoints of providing a thin, transparent, and flexible electrode.

Furthermore, it is preferable to have an electrode protective layer on the second transparent electrode, and that the electrode protective layer contains a metal oxide improves adhesion with the transparent sealing substrate and provides a stronger sealing. It is preferable from the viewpoint of stopping.

Hereinafter, the present invention, its components, and modes and modes for carrying out the present invention will be described in detail. In the present application, “˜” is used to mean that the numerical values described before and after it are included as a lower limit value and an upper limit value.

<Outline of Organic EL Device of the Present Invention>
The organic EL device of the present invention includes a functional layer containing at least a white pigment, a first transparent electrode, an organic light emitting layer, a second transparent electrode, and a transparent seal on a flexible substrate on which a metal layer or a metal foil is laminated. Provided with a stop base material in this order, this configuration provides a lightweight and light organic electroluminescence element with high gas barrier properties, high light extraction efficiency, and reduced color shift can do.

Here, “flexibility” means that a substrate or a base material is wound around a φ (diameter) 50 mm roll, and cracks or the like do not occur before and after winding with a constant tension. The flexible substrate or base material is more preferably a substrate or base material that can be wound around a φ30 mm roll, and a resin material described later is preferably used.

The term “transparent” as used in the present invention refers to the light transmittance (%) at a light wavelength of 550 nm using a spectrophotometer (U-3300 manufactured by Hitachi High-Technologies Corporation) for each element constituting the organic EL element. ) Is measured, it has a light transmittance of 50% or more. The light transmittance of each element constituting the organic EL element is preferably 60% or more, more preferably 70% or more, and particularly preferably 80% or more.

<Details of the organic EL device of the present invention>
[Configuration of organic EL element]
An example of the organic EL element of the present invention is shown in FIG. However, the present invention is not limited to this.

The organic EL device 100 of the present invention is provided on a substrate 110, and is configured by using a functional layer 106 containing at least a white pigment, a first transparent electrode 101, an organic material, and the like in order from the substrate 110 side. The light emitting layer 103, the second transparent electrode (counter electrode) 102, and the transparent sealing substrate 105 are laminated in this order. Since the substrate 110 is composed of a metal layer or a metal foil, it is preferable to have an insulating layer (not shown) in order to increase the degree of freedom of electrode installation. The end of the first transparent electrode 101 (electrode layer 101b) has the shape of an extraction electrode, and the first transparent electrode 101 and an external power source (not shown) are electrically connected via the extraction electrode. . The organic EL element 100 is a top emission type configured such that generated light (emitted light h) is extracted from the transparent sealing substrate 105 side.

The organic EL device 100 of the present invention has the above-mentioned substrate, the functional layer containing the white pigment, the first transparent electrode, the organic light emitting layer, the second transparent electrode, and the transparent sealing substrate all having flexibility. An organic EL element having flexibility is realized.

The layer structure of the organic EL element 100 is not limited and may be a general layer structure. Here, the first transparent electrode 101 functions as an anode (that is, an anode), and the second transparent electrode 102 functions as a cathode (that is, a cathode). In this case, for example, the organic light emitting layer 103 is formed by laminating a hole injection layer 103a / a hole transport layer 103b / a light emission layer 103c / an electron transport layer 103d / an electron injection layer 103e in this order from the first transparent electrode 101 side which is an anode. Although the structure is illustrated, it is essential to have the light emitting layer 103c formed using at least an organic material. The hole injection layer 103a and the hole transport layer 103b may be provided as a hole transport injection layer. The electron transport layer 103d and the electron injection layer 103e may be provided as an electron transport injection layer. Among these organic light emitting layers 103, for example, the electron injection layer 103e may be made of an inorganic material.

In addition to these layers, the organic light emitting layer 103 may be laminated with a hole blocking layer, an electron blocking layer, or the like as necessary. Furthermore, the light emitting layer 103c may have a structure in which each color light emitting layer for generating light emitted in each light wavelength region is laminated, and each of these color light emitting layers is laminated via a non-light emitting intermediate layer. The intermediate layer may function as a hole blocking layer and an electron blocking layer. Further, the second transparent electrode 102 as the cathode may also have a laminated structure as necessary. In such a configuration, only a portion where the organic light emitting layer 103 is sandwiched between the first transparent electrode 101 and the second transparent electrode 102 becomes a light emitting region in the organic EL element 100.

Further, in the layer configuration as described above, an auxiliary electrode (not shown) is provided in contact with the electrode layer 101b of the first transparent electrode 101 for the purpose of reducing the resistance of the first transparent electrode 101. Also good.

The organic EL element 100 configured as described above is sealed on the substrate 110 by the transparent sealing base material 105 for the purpose of preventing deterioration of the organic light emitting layer 103 formed using an organic material or the like. Yes. The transparent sealing substrate 105 is fixed to the surface of the substrate 110 via an adhesive layer. However, the extraction electrode portion of the first transparent electrode 101 and the terminal portion of the second transparent electrode 102 are exposed from the transparent sealing substrate 105 in a state in which the organic light emitting layer 103 maintains insulation from each other on the substrate 110. It is assumed that it is provided. The transparent sealing substrate 105 preferably has a gas barrier layer in order to protect the organic light emitting layer 103 from the humidity of the external environment.

Moreover, it is preferable to provide the smooth layer 107 between the functional layer 106 containing a white pigment and the first transparent electrode 101, and the surface of the functional layer 106 containing the white pigment formed on the substrate 110 and the substrate is preferably provided. By flattening the unevenness, it is possible to prevent an electrode short-circuit (electrical short-circuit) due to storage with time.

Furthermore, it is preferable to provide an electrode protective layer 104 between the second transparent electrode 102 and the transparent sealing substrate 105, and the electrode surface is protected and planarized, and the transparent sealing substrate 105 is solid-sealed. Therefore, stronger sealing can be achieved, which is preferable.

[Method for producing organic EL element]
In the method for producing an organic EL device of the present invention, a functional layer containing at least a white pigment, a first transparent electrode, an organic light emitting layer and a second transparent electrode are laminated on a substrate, and further laminated with a transparent sealing substrate. It is preferable to seal.

Here, as an example, a method for manufacturing the organic EL element 100 shown in FIG. 2 will be described.

<Lamination process>
In the method for producing an organic EL element of the present invention, a functional layer 106 containing at least a white pigment, a first transparent electrode 101, an organic light emitting layer 103, and a second transparent electrode 102 are laminated on a substrate 110, and further transparent sealing is performed. Lamination is performed with the substrate 105.

First, a flexible substrate 110 on which a metal layer or a metal foil is laminated is prepared, and a functional layer 106 containing a white pigment as a light-scattering / reflecting layer is preferably formed on the substrate 110 in a thickness range of 10 to 50 μm. And formed by a coating method.

Next, the smooth layer 107 is formed by a coating method, for example, with a layer thickness of preferably 0.1 to 5 μm, and an organic compound having at least one atom selected from a nitrogen atom and a sulfur atom thereon. The underlying layer 101a is formed by an appropriate method such as an evaporation method so as to have a layer thickness of 1 μm or less, preferably in the range of 10 to 100 nm.

Next, the electrode layer 101b made of silver or an alloy containing silver as a main component is formed on the base layer 101a by an appropriate method such as vapor deposition so that the layer thickness is 30 nm or less, preferably in the range of 5 to 30 nm. The first transparent electrode 101 is formed to be an anode. At the same time, an extraction electrode portion connected to an external power source is formed at the end of the first transparent electrode 101 by an appropriate method such as a vapor deposition method.

Next, a hole injection layer 103a, a hole transport layer 103b, a light emitting layer 103c, an electron transport layer 103d, and an electron injection layer 103e are stacked in this order on this, thereby forming the organic light emitting layer 103.

Each of these layers can be formed by spin coating, casting, ink jet, vapor deposition, printing, etc., but it is easy to obtain a homogeneous layer and it is difficult to generate pinholes. The vapor deposition method or the spin coating method is particularly preferable. Furthermore, different formation methods may be applied for each layer. When a vapor deposition method is employed for forming each of these layers, the vapor deposition conditions vary depending on the type of compound used, etc., but generally a resistance heating boat is used and the boat heating temperature is 50 to 450 ° C., and the degree of vacuum is 1 × 10 ⁻⁶ to It is desirable to appropriately select each condition within the range of 1 × 10 ⁻² Pa, vapor deposition rate of 0.01 to 50 nm / second, substrate temperature of −50 to 300 ° C., and layer thickness of 0.1 to 5 μm.

After forming the organic light emitting layer 103 as described above, the second transparent electrode 102 serving as a cathode is formed on the upper portion by an appropriate forming method such as a vapor deposition method or a sputtering method. At this time, the second transparent electrode 102 is formed in a pattern in which a terminal portion is drawn from the upper side of the organic light emitting layer 103 to the periphery of the substrate 110 while being insulated from the first transparent electrode 101 by the organic light emitting layer 103. To do.

It is preferable to form the electrode protective layer 104 in order to smooth the surface of the transparent second electrode and to provide strength and protect it. The electrode protective layer is preferably formed by an appropriate method such as the coating method or the vapor deposition method so that the layer thickness is 1 μm or less, preferably in the range of 10 to 100 nm.

Next, the transparent sealing substrate 105 provided with the adhesive layer is covered on the electrode protective layer 104 and the substrate 110 so as to cover the first transparent electrode, the organic light emitting layer, and the second transparent electrode by a method such as thermocompression bonding. The organic EL element 100 is manufactured by laminating and sealing.

Hereinafter, details of each main layer for constituting the organic EL element 100 described above and a manufacturing method thereof will be further described.

〔substrate〕
The flexible substrate 110 according to the present invention includes (i) a resin base layer laminated or coated with a metal layer, (ii) a metal layer sandwiched between two resin base layers, and (iii) It is preferably composed of any one of metal foils. The metal layer or metal foil on the flexible substrate serves as a gas barrier layer that minimizes the transmission of oxygen and moisture to the organic EL element. Therefore, the thickness of the metal layer or the metal foil is preferably in the range of 5 to 500 μm, more preferably in the range of 10 to 100 μm, in order to exhibit the function as a gas barrier layer. If it is the thickness in this range, the function as a gas barrier layer can be exhibited, without impairing flexibility.

The gas barrier layer has a water vapor permeability (25 ± 0.5 ° C., relative humidity 90 ± 2% environment) measured by a method according to JIS K 7129: 1992, 0.01 g / (m ² · 24 hours. The following gas barrier properties are preferred, and the oxygen permeability measured by a method according to JIS K 7126: 1987 is 1 × 10 ⁻³ ml / (m ² · 24 hours · atm) or less, water vapor It is more preferable that the gas permeability is 1 × 10 ⁻⁵ g / (m ² · 24 hours) or less.

In one embodiment, as shown in FIG. 1A, a substrate 110 according to the present invention is configured by a resin base material 110a laminated on or coated with a metal layer 110b. The method for laminating the metal layer or metal foil according to the present invention on the resin substrate 101a is not particularly limited. For example, a metal plate or a metal foil may be bonded to the resin base material with an adhesive, or a metal material may be formed on the resin base material as a metal layer by a vapor deposition method. In the present invention, it is preferable to use a vapor deposition method in order to form a uniform metal layer, and a vacuum vapor deposition method using a resistance heating boat is preferable because it is easy to form a more uniform metal layer. The metal material is not particularly limited, but stainless steel, iron (Fe), aluminum (Al), nickel (Ni), cobalt (Co), copper (Cu), and alloys thereof are preferably used. Among them, aluminum having high reflectance and light weight is preferably used, and aluminum is preferable because it becomes an excellent barrier film against water and oxygen.

As another embodiment, as shown in FIG. 1B, the substrate 110 may be composed of a metal layer 110d sandwiched between two layers of resin base materials 110c and 101e.

It is also preferable to provide an insulating layer (not shown) between the metal layer 110b and the first transparent electrode 101. The insulating layer may be a polymer layer formed by spin coating or a dielectric layer, and may be, for example, an inorganic oxide or a spin-on-glass (SOG). This insulating layer also functions as a planarization layer.

The resin substrate 110a used for the substrate 110 is a transparent and flexible resin substrate, and can be selected from conventionally known resin film substrates. The resin substrate preferably used in the present invention preferably has gas barrier properties such as moisture resistance / gas permeability resistance required for the organic EL element.

In the present invention, the light transmittance of the resin base material is preferably 70% or more, more preferably 80% or more, and further preferably 90% or more.

The transparent resin base material that can be used in the present invention is a conventionally known base material, for example, acrylic resins such as acrylic ester, methacrylic ester, PMMA, polyethylene terephthalate (PET), polybutylene terephthalate, polyethylene. Naphthalate (PEN), polycarbonate (PC), polyarylate, polyvinyl chloride (PVC), polyethylene (PE), polypropylene (PP), polystyrene (PS), nylon (Ny), aromatic polyamide, polyether ether ketone, Examples include resin films such as polysulfone, polyether sulfonate, polyimide, polyetherimide, polyolefin, and epoxy resin, and cycloolefin-based and cellulose ester-based films can also be used. In addition, a heat-resistant transparent film (product name: Sila-DEC, manufactured by Chisso Corporation) having silsesquioxane having an organic-inorganic hybrid structure as a basic skeleton, and a resin film obtained by laminating two or more layers of the resin material, etc. Can be mentioned.

From the viewpoint of cost and availability, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polycarbonate (PC), acrylic resin and the like are preferably used.

Of these, a biaxially stretched polyethylene terephthalate (PET) film and a biaxially stretched polyethylene naphthalate (PEN) film are preferred in terms of transparency, heat resistance, ease of handling, strength, and cost.

Furthermore, in order to suppress the shrinkage at the time of thermal expansion to the maximum, a low heat recovery treatment product that has been subjected to treatment such as thermal annealing is most preferable.

The thickness of the resin substrate is preferably in the range of 10 to 500 μm, more preferably in the range of 20 to 250 μm, and still more preferably in the range of 30 to 150 μm. When the thickness of the resin base material is in the range of 10 to 500 μm, a stable gas barrier property can be obtained, and the resin base material is suitable for conveyance in a roll-to-roll system.

In yet another embodiment, the substrate 110 is a metal foil coated with an insulating layer. The metal foil may be formed of aluminum, copper, or stainless steel. The insulating layer is as described above. In this case, the metal foil functions as a gas barrier layer.

[Functional layer containing white pigment]
The functional layer 106 containing a white pigment according to the present invention is a layer that functions as a light diffusion reflection layer, and has a light diffusion reflection layer (white light) having a relative diffuse reflectance of 80% or more in a light wavelength range of 380 to 550 nm. It is also called a diffuse reflection layer. A more preferable relative diffuse reflectance is 85% or more, and further preferably 90% or more. The relative diffuse reflectance can be measured with a commercially available spectrophotometer. For example, the relative diffuse reflectance can be measured by mounting an integrating sphere on a Hitachi spectrophotometer U-4100 manufactured by Hitachi or a UV-3101 spectrophotometer manufactured by Shimadzu Corporation.

In order to realize the relative diffuse reflectance, the functional layer preferably contains at least a white pigment. More preferably, the layer contains a white pigment and a binder resin and is formed by a coating method.

As the white pigment that can be used in the present invention, a known white pigment can be used. For example, barium sulfate, titanium oxide, basic lead carbonate (2PbCO ₃ .Pb (OH) ₂ (lead white), etc.), Basic lead sulfate (2PbSO ₄ · Pb (OH) ₂ etc.), basic lead silicate (Pb ₂ SiO ₄ · Pb (OH) ₂ etc.), zinc white (ZnO (zinc oxide)), zinc sulfide, lithopone ( And a mixture of zinc sulfide and barium sulfate) and antimony trioxide. Of these, barium sulfate and titanium oxide are preferable, and barium sulfate is particularly preferable.

The content of the white pigment in the functional layer is preferably in the range of 50 to 90% by mass, more preferably in the range of 60 to 90% by mass.

Hereinafter, the functional layer containing the white pigment according to the present invention will be described using barium sulfate as an example of the white pigment.

The functional layer 106 containing the white pigment according to the present invention is preferably composed of barium sulfate and a binder resin. Examples of the binder resin include urethane-based, acrylic-based, epoxy-based, vinyl-based, polyester-based, polyamide-based, and rubber-based synthetic resins. In order to give particularly high flexibility to the functional layer, it is preferable to select a binder resin having a Shore hardness of 20 or less in JIS-Z2246.

Barium sulfate contained in the functional layer 106 containing a white pigment is used as a light reflecting agent. The ratio of the barium sulfate to the binder resin is preferably not more than the critical pigment concentration from the viewpoint of physical properties of the coating film in order to prevent the coating film from being easily cohesive and broken.

In addition to those described above, various additives such as a dispersant, a leveling agent, an anti-aging agent, a plasticizer, an antistatic agent, and a fluorescent brightening agent can be added to the functional layer 106 containing a white pigment. .

Further, the layer thickness of the functional layer 106 containing a white pigment is preferably in the range of 1 to 100 μm, and more preferably in the range of 5 to 100 μm, in order to efficiently perform light diffuse reflection. When the thickness is 1 μm or more, light having a light wavelength of 450 nm or less can be efficiently reflected, and the function as a light reflecting material can be easily achieved.

On the other hand, the upper limit of the layer thickness does not need to be specified in particular, but if it is within 100 μm, the flexibility of the organic EL element can be satisfied together with the effect of using a resin capable of imparting flexibility.

The functional layer 106 containing a white pigment is preferably formed by applying a coating solution containing the barium sulfate, the binder resin, and the additive. Specific examples of the coating method include, for example, a roller coating method. , A flow coating method, an ink jet method, a spray coating method, a printing method, a dip coating method, a casting film forming method, a bar coating method, a gravure printing method, and the like, which are appropriately selected. The functional layer 106 containing a white pigment is formed with a predetermined layer thickness and then dried by a known drying method.

[Smooth layer]
The smooth layer 107 according to the present invention is free from adverse effects such as deterioration of storage stability and short circuit (electrical short circuit) in a high temperature and high humidity atmosphere due to the unevenness of the surface of the functional layer 106 containing the substrate 110 and the white pigment. The main purpose is to prevent.

It is important that the smooth layer 107 according to the present invention has a flatness that allows the first transparent electrode 101 to be satisfactorily formed thereon, and the surface property is an arithmetic average roughness Ra in the range of 0.5 to 50 nm. It is preferable to be within. More preferably, it is 30 nm or less, Especially preferably, it is 10 nm or less, Most preferably, it is 5 nm or less. That is, by setting the arithmetic average roughness Ra of the surface of the smooth layer 107 on the organic light emitting layer 103 side within the range of 0.5 to 50 nm, defects such as a short circuit of the first transparent electrode to be laminated can be suppressed. . As for the arithmetic average roughness Ra, 0 nm is preferable, but 0.5 nm is set as a lower limit value as a practical level limit value.

Further, in the present application, the arithmetic average roughness Ra of the surface represents an arithmetic average roughness based on JIS B0601-2001.

The surface roughness (arithmetic mean roughness Ra) is an uneven cross-section measured continuously with a detector having a stylus with a minimum tip radius using an AFM (Atomic Force Microscope: Digital Instruments). It was calculated from the curve, measured three times in a section with a measuring direction of 30 μm with a stylus having a minimum tip radius, and obtained from the average roughness related to the amplitude of fine irregularities.

The smoothing layer 107 receives light emitted from the organic light emitting layer 103. Therefore, the average refractive index nf of the smooth layer 107 is preferably a value close to the refractive index of the organic functional layer included in the organic light emitting layer 103. Specifically, since an organic material having a high refractive index is generally used for the organic light emitting layer 103, the smoothing layer 107 has the shortest emission maximum wavelength among the emission maximum wavelengths of the emitted light from the organic light emitting layer 103. The high refractive index layer preferably has an average refractive index nf of 1.50 or more, particularly 1.65 or more and less than 2.50. As long as the average refractive index nf is 1.50 or more and less than 2.50, it may be formed of a single material or a mixture. In the case of such a mixed system, the average refractive index nf of the smooth layer 1 uses a calculated refractive index calculated by a total value obtained by multiplying the refractive index specific to each material by the volume ratio. In this case, the refractive index of each material may be less than 1.50 or more than 2.50, and the average refractive index nf of the mixed film should satisfy 1.50 or more and less than 2.50. That's fine.

Here, the “average refractive index nf” of the smooth layer is the refractive index of a single material when formed of a single material, and in the case of a mixed system, the desired volume based on the density of each material. By calculating and mixing the mass so as to be a ratio, the calculated refractive index calculated by the sum of the refractive index specific to each material multiplied by the volume ratio is calculated.

The refractive index is measured by preparing a smooth layer single film and irradiating the light having the shortest light emission maximum wavelength among the light emission maximum wavelengths of the light emitted from the light emitting unit in an atmosphere at 25 ° C. (Atago, DR-M2) is used.

As the binder used for the smooth layer 107, a known resin can be used without any particular limitation. For example, acrylic ester, methacrylic ester, polyethylene terephthalate (PET), polybutylene terephthalate, polyethylene naphthalate (PEN), polycarbonate (PC), polyarylate, polyvinyl chloride (PVC), polyethylene (PE), polypropylene (PP), polystyrene (PS), nylon (Ny), aromatic polyamide, polyether ether ketone, polysulfone, polyether sulfone, polyimide , Resin films such as polyetherimide, heat-resistant transparent film based on silsesquioxane having an organic-inorganic hybrid structure (product name: Sila-DEC, manufactured by Chisso Corporation), perfluoroal Fluorine-containing silane compounds (for example, (heptadecafluoro-1,1,2,2-tetradecyl) triethoxysilane), fluorine-containing monomers and monomers containing a crosslinkable group as structural units A polymer etc. are mentioned. These resins can be used in combination of two or more. Among these, those having an organic-inorganic hybrid structure are preferable.

Also, the following hydrophilic resins can be used. Examples of the hydrophilic resin include water-soluble resins, water-dispersible resins, colloid-dispersed resins, and mixtures thereof. Examples of the hydrophilic resin include acrylic resins, polyester resins, polyamide resins, polyurethane resins, fluorine resins, etc., for example, polyvinyl alcohol, gelatin, polyethylene oxide, polyvinyl pyrrolidone, casein, starch, agar, carrageenan, polyacrylic resin. Polymers such as acid, polymethacrylic acid, polyacrylamide, polymethacrylamide, polystyrene sulfonic acid, cellulose, hydroxyl ethyl cellulose, carboxyl methyl cellulose, hydroxyl ethyl cellulose, dextran, dextrin, pullulan, water-soluble polyvinyl butyral can be mentioned, but these Among these, polyvinyl alcohol is preferable.

The polymer used as the binder resin may be used alone or as a mixture of two or more if necessary.

Similarly, conventionally known resin particles (emulsion) and the like can also be suitably used as a binder.

Also, as the binder, a resin curable mainly by ultraviolet rays or an electron beam, that is, a mixture of a thermoplastic resin and a solvent in an ionizing radiation curable resin or a thermosetting resin can be suitably used.

Such a binder resin is preferably a polymer having a saturated hydrocarbon or polyether as the main chain, and more preferably a polymer having a saturated hydrocarbon as the main chain.

Also, the binder is preferably crosslinked. The polymer having a saturated hydrocarbon as the main chain is preferably obtained by a polymerization reaction of an ethylenically unsaturated monomer. In order to obtain a crosslinked binder, it is preferable to use a monomer having two or more ethylenically unsaturated groups.

A fine particle sol contained in a binder contained in the smooth layer 107 can also be suitably used.

Further, the lower limit of the particle diameter dispersed in the binder contained in the smooth layer 107 having a high refractive index is usually preferably 5 nm or more, more preferably 10 nm or more, and further preferably 15 nm or more. . Moreover, as an upper limit of the particle diameter disperse | distributed to a binder, it is preferable that it is 70 nm or less, It is more preferable that it is 60 nm or less, It is further more preferable that it is 50 nm or less. When the particle diameter dispersed in the binder is in the range of 5 to 70 nm, it is preferable in that high transparency can be obtained. As long as the effect of the present invention is not impaired, the particle size distribution is not limited, and may be wide or narrow and may have a plurality of distributions.

The particles contained in the smooth layer 107 according to the present invention are more preferably TiO ₂ (titanium dioxide sol) from the viewpoint of stability. Among TiO ₂ , rutile type is more preferable than anatase type, since the catalytic activity is low, and the weather resistance of the smooth layer 107 and the adjacent layer becomes high and the refractive index is high.

Examples of a method for preparing a titanium dioxide sol that can be used in the present invention include JP-A 63-17221, JP-A 7-819, JP-A 9-165218, and JP-A 11-43327. Can be referred to.

The thickness of the smooth layer 107 needs to be somewhat thick in order to reduce the surface roughness of the functional layer containing the substrate and the white pigment, but on the other hand, it needs to be thin enough not to cause energy loss due to absorption. Specifically, it is preferably in the range of 0.1 to 5 μm, more preferably in the range of 0.5 to 2 μm.

For example, after forming a functional layer containing a white pigment, the smooth layer 107 is prepared by mixing a dispersion in which nano-TiO ₂ particles are dispersed and a resin solution, and filtering with a filter to obtain a smooth layer preparation solution. And after apply | coating the obtained smooth layer preparation solution on the functional layer containing a white pigment and drying, it heats and produces a smooth layer.

The smooth layer 107 is also preferably provided with a gas barrier property, and the material that provides such a gas barrier property may be a material that has a function of suppressing intrusion of elements that cause deterioration of elements such as moisture and oxygen. For example, silicon oxide, silicon dioxide, silicon nitride, or the like can be used.

For example, it is also preferable to apply a coating solution containing the following inorganic precursor compound and form it by a modification treatment.

The inorganic precursor compound used in the present invention is not particularly limited as long as it is a compound capable of forming a metal oxide, a metal nitride, or a metal oxynitride by vacuum ultraviolet irradiation under a specific atmosphere, but is suitable for the present invention. The compound is preferably a compound that can be modified at a relatively low temperature as described in JP-A-8-112879.

Specifically, as the inorganic precursor compound, polysiloxane (including polysilsesquioxane) having Si—O—Si bond, polysilazane having Si—N—Si bond, Si—O—Si bond and Si— Polysiloxazan and the like containing both N—Si bonds can be raised. These can be used in combination of two or more. Moreover, it can be used even if different compounds are sequentially laminated or simultaneously laminated.

Among them, polysilazane is preferable, and the polysilazane used in the present invention is a polymer having a silicon-nitrogen bond, and is composed of Si—N, Si—H, NH, etc., SiO ₂ , Si ₃ N ₄ and the intermediate of both. An inorganic precursor polymer such as a solid solution SiO _x N _y (x: 0.1 to 1.9, y: 0.1 to 1.3).

The polysilazane preferably used in the present invention is represented by the following general formula (A).

Formula (A)
— [Si (R ₁ ) (R ₂ ) —N (R ₃ )] —
In general formula (A), R ₁ , R ₂ and R ₃ each represent a hydrogen atom, an alkyl group, an alkenyl group, a cycloalkyl group, an aryl group, an alkylsilyl group, an alkylamino group or an alkoxy group.

In the present invention, perhydropolysilazane in which all of R _1, R ₂ and R ₃ are hydrogen atoms is particularly preferred from the viewpoint of compactness.

Polysilazane is commercially available in the form of a solution dissolved in an organic solvent, and the commercially available product can be used as a polysilazane-containing coating solution as it is. Examples of commercially available polysilazane solutions include NN120-20, NAX120-20, and NL120-20 manufactured by AZ Electronic Materials Co., Ltd.

The coating solution containing the polysilazane can be applied and dried, and then subjected to a modification treatment by irradiation with vacuum ultraviolet rays.

As an organic solvent for preparing a coating liquid containing polysilazane, it is preferable to avoid using an alcohol or water-containing one that easily reacts with polysilazane. Examples of applicable organic solvents include hydrocarbon solvents such as aliphatic hydrocarbons, alicyclic hydrocarbons, and aromatic hydrocarbons, ethers such as halogenated hydrocarbon solvents, aliphatic ethers, and alicyclic ethers. Specific examples include hydrocarbons such as pentane, hexane, cyclohexane, toluene, xylene, solvesso and turben, halogen hydrocarbons such as methylene chloride and trichloroethane, and ethers such as dibutyl ether, dioxane and tetrahydrofuran. These organic solvents may be selected according to purposes such as the solubility of polysilazane and the evaporation rate of the organic solvent, and a plurality of organic solvents may be mixed.

The concentration of polysilazane in the coating solution for forming a smooth layer containing polysilazane varies depending on the layer thickness of the smooth layer and the pot life of the coating solution, but is preferably in the range of 0.2 to 35% by mass.

In order to promote the modification to silicon oxynitride, the coating solution for forming a smooth layer includes an amine catalyst, a Pt compound such as Pt acetylacetonate, a Pd compound such as propionic acid Pd, and an Rh compound such as Rh acetylacetonate. A metal catalyst can also be added. In the present invention, it is particularly preferable to use an amine catalyst. Specific amine catalysts include N, N-diethylethanolamine, N, N-dimethylethanolamine, triethanolamine, triethylamine, 3-morpholinopropylamine, N, N, N ′, N′-tetramethyl-1 , 3-diaminopropane, N, N, N ′, N′-tetramethyl-1,6-diaminohexane and the like.

The amount of these catalysts added to the polysilazane is preferably in the range of 0.1 to 10% by mass, and preferably in the range of 0.2 to 5% by mass with respect to the total mass of the smooth layer forming coating solution. More preferably, it is more preferably in the range of 0.5 to 2% by mass. By setting the addition amount of the catalyst within the range specified above, excessive silanol formation due to rapid progress of the reaction, reduction in film density, increase in film defects, and the like can be avoided.

Arbitrary appropriate wet coating methods may be employ | adopted as a method of apply | coating the coating liquid for smooth layer formation containing polysilazane. Specific examples include a roller coating method, a flow coating method, an ink jet method, a spray coating method, a printing method, a dip coating method, a casting film forming method, a bar coating method, and a gravure printing method.

The thickness of the coating film can be appropriately set according to the purpose. For example, the thickness of the coating film is preferably in the range of 50 nm to 2 μm as the thickness after drying, more preferably in the range of 70 nm to 1.5 μm, and in the range of 100 nm to 1 μm. Is more preferable.

The smooth layer is a step of irradiating the layer containing polysilazane with vacuum ultraviolet (VUV), and at least a part of the polysilazane is modified into silicon oxynitride.

Here, perhydropolysilazane will be described as an example of the presumed mechanism in which the coating film containing polysilazane is modified in the vacuum ultraviolet irradiation step and becomes a specific composition of SiO _x N _y .

Perhydropolysilazane can be represented by a composition of “— (SiH ₂ —NH) _n —”. In the case of SiO _x N _y , x = 0 and y = 1. An external oxygen source is required for x> 0,
(I) oxygen and moisture contained in the polysilazane coating solution,
(Ii) oxygen and moisture taken into the coating film from the atmosphere of the coating and drying process,
(Iii) oxygen, moisture, ozone, singlet oxygen taken into the coating film from the atmosphere in the vacuum ultraviolet irradiation process,
(Iv) Oxygen and moisture moving into the coating film as outgas from the substrate side by heat applied in the vacuum ultraviolet irradiation process,
(V) When the vacuum ultraviolet ray irradiation step is performed in a non-oxidizing atmosphere, when moving from the non-oxidizing atmosphere to the oxidizing atmosphere, oxygen and moisture taken into the coating film from the atmosphere,
Etc. become oxygen sources.

On the other hand, for y, the condition under which nitriding proceeds rather than the oxidation of Si is considered to be very special, so basically 1 is the upper limit.

Also, from the relationship of Si, O, N bond, x and y are basically in the range of 2x + 3y ≦ 4. In the state of y = 0 where the oxidation has progressed completely, the coating film contains silanol groups, and there are cases where 2 <x <2.5.

The reaction mechanism presumed to produce silicon oxynitride and further silicon oxide from perhydropolysilazane in the vacuum ultraviolet irradiation process will be described below.

(1) Dehydrogenation and accompanying Si—N bond formation Si—H bonds and N—H bonds in perhydropolysilazane are relatively easily cleaved by excitation with vacuum ultraviolet irradiation and the like. It is considered that they are recombined as N (a dangling bond of Si may be formed). That is, the cured as SiN _y composition without oxidizing. In this case, the polymer main chain is not broken. The breaking of Si—H bonds and N—H bonds is promoted by the presence of a catalyst and heating. The cut H is released out of the membrane as H ₂ .

(2) Formation of Si—O—Si Bonds by Hydrolysis and Dehydration Condensation Si—N bonds in perhydropolysilazane are hydrolyzed by water, and the polymer main chain is cleaved to form Si—OH. Two Si—OH are dehydrated and condensed to form a Si—O—Si bond and harden. This is a reaction that occurs even in the atmosphere, but during vacuum ultraviolet irradiation in an inert atmosphere, it is considered that water vapor generated as outgas from the resin base material by the heat of irradiation becomes the main moisture source. When the moisture is excessive, Si—OH that cannot be dehydrated and condensed remains, and a cured film having a low gas barrier property represented by a composition of SiO _2.1 to SiO _2.3 is obtained.

(3) Direct oxidation by singlet oxygen, formation of Si—O—Si bond When a suitable amount of oxygen is present in the atmosphere during irradiation with vacuum ultraviolet rays, singlet oxygen having very strong oxidizing power is formed. H or N in the perhydropolysilazane is replaced with O to form a Si—O—Si bond and is cured. It is considered that recombination of the bond may occur due to cleavage of the polymer main chain.

(4) Oxidation with Si-N bond cleavage by vacuum ultraviolet irradiation and excitation Since the energy of vacuum ultraviolet light is higher than the bond energy of Si-N in perhydropolysilazane, the Si-N bond is broken and oxygen is surrounded by oxygen. In the presence of an oxygen source such as ozone or water, it is considered that the Si—O—Si bond or Si—O—N bond is formed by oxidation. It is considered that recombination of the bond may occur due to the cleavage of the polymer main chain.

Adjustment of the composition of silicon oxynitride in the layer obtained by subjecting the polysilazane-containing layer to vacuum ultraviolet irradiation can be performed by appropriately controlling the oxidation state by appropriately combining the oxidation mechanisms (1) to (4) described above. .

<Vacuum ultraviolet irradiation device with excimer lamp>
As a preferable ultraviolet irradiation apparatus for modifying polysilazane, a rare gas excimer lamp that emits vacuum ultraviolet rays of 100 to 230 nm is specifically mentioned.

Noble gas atoms such as Xe, Kr, Ar, Ne, etc. are called inert gases because they are chemically bonded and do not form molecules. However, rare gas atoms (excited atoms) that have gained energy by discharge or the like can be combined with other atoms to form molecules.

For example, when the rare gas is Xe (xenon), excimer light of 172 nm is emitted when the excited excimer molecule Xe ₂ ^* transitions to the ground state, as shown in the following reaction formula.

e + Xe → Xe ^*
Xe ^* + 2Xe → Xe ₂ ^* + Xe
Xe ₂ ^* → Xe + Xe + hν (172 nm)
A feature of the excimer lamp is that the radiation is concentrated on one wavelength, and since only the necessary light is not emitted, the efficiency is high. Moreover, since extra light is not radiated | emitted, the temperature of a target object can be kept comparatively low. Furthermore, since no time is required for starting and restarting, instantaneous lighting and blinking are possible.

As a light source for efficiently irradiating excimer light, there is a dielectric barrier discharge lamp.

A dielectric barrier discharge lamp has a structure in which a discharge is generated between electrodes via a dielectric. Generally, at least one electrode is disposed between a discharge vessel made of a dielectric and the outside thereof. That's fine. As a dielectric barrier discharge lamp, for example, a rare gas such as xenon is enclosed in a double cylindrical discharge vessel composed of a thick tube and a thin tube made of quartz glass, and a mesh-like second electrode is formed outside the discharge vessel. There is one in which one electrode is provided and another electrode is provided inside the inner tube.

The dielectric barrier discharge lamp generates a dielectric barrier discharge inside the discharge vessel by applying a high-frequency voltage or the like between the electrodes, and generates excimer light when excimer molecules such as xenon generated by the discharge dissociate.

Excimer lamps can be lit with low power input because of their high light generation efficiency. In addition, since light having a long wavelength that causes a temperature rise is not emitted and energy is emitted at a single wavelength in the ultraviolet region, the temperature rise of the irradiation object due to the irradiation light itself is suppressed.

Preferably illuminance of the vacuum ultraviolet rays in the coated surface of the polysilazane coating film is subjected is in the range of 30 ~ 200mW / cm ^2, and more preferably in a range of 50 ~ 160mW / cm ^2. If it is 30 mW / cm ² or more, there is no concern about the reduction of the reforming efficiency, and if it is 200 mW / cm ² or less, the coating film is not ablated and the substrate is not damaged.

Irradiation energy amount of the VUV in the polysilazane coating film surface is preferably in the range of 200 ~ 10000mJ / cm ^2, and more preferably in a range of 500 ~ 5000mJ / cm ^2. If it is 200 mJ / cm ² or more, the modification can be sufficiently performed, and if it is 10000 mJ / cm ² or less, it is not over-reformed and cracking and thermal deformation of the resin substrate can be prevented. .

[First transparent electrode]
As the first transparent electrode, all the electrodes that can be normally used for organic EL elements can be used. Specifically, aluminum, silver, magnesium, lithium, magnesium / same mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, indium, lithium / aluminum mixture, rare earth metal, ITO, ZnO, TiO ₂ , An oxide semiconductor such as SnO ₂ can be given.

For example, as shown in FIG. 2, the first transparent electrode 101 preferably has a two-layer structure in which a base layer 101a and an electrode layer 101b formed thereon are sequentially laminated from the substrate 110 side. Among these, the electrode layer 101b is a layer formed using, for example, silver or an alloy containing silver as a main component, and the base layer 101a is, for example, at least one kind of atom selected from a nitrogen atom and a sulfur atom. It is preferable that it is a layer containing the organic compound which has.

Note that the transparency of the first transparent electrode 101 means that the light transmittance at a light wavelength of 550 nm is 50% or more. The main component in the electrode layer 101b means that the content in the electrode layer 101b is 98% by mass or more.

(1) Underlayer The underlayer 101a is a layer provided on the substrate 110 side of the electrode layer 101b. The material constituting the base layer 101a is not particularly limited as long as it can suppress the aggregation of silver when forming the electrode layer 101b made of silver or an alloy containing silver as a main component. , Organic compounds having at least one atom selected from a nitrogen atom and a sulfur atom.

The compound containing a nitrogen atom constituting the underlayer is not particularly limited as long as it is an organic compound containing a nitrogen atom in the molecule, but is preferably a compound having a heterocycle having a nitrogen atom as a heteroatom. . Examples of the heterocycle having a nitrogen atom as a hetero atom include aziridine, azirine, azetidine, azeto, azolidine, azole, azinane, pyridine, azepan, azepine, imidazole, pyrazole, oxazole, thiazole, imidazoline, pyrazine, morpholine, thiazine, indole, Examples include isoindole, benzimidazole, purine, quinoline, isoquinoline, quinoxaline, cinnoline, pteridine, acridine, carbazole, benzo-C-cinnoline, porphyrin, chlorin, choline and the like.

The organic compound having a sulfur atom is preferably a compound having a sulfide bond, disulfide bond, mercapto group, sulfone group, thiocarbonyl bond or the like in the molecule. Among these, it is preferable to have a sulfide bond or a mercapto group.

The organic compound may be one kind or a mixture of two or more kinds. In addition, it is allowed to mix a compound having no nitrogen atom and sulfur atom within a range that does not impair the effect of the underlayer.

When the underlayer 101a is made of a low refractive index material (refractive index less than 1.7), the upper limit of the layer thickness is preferably less than 50 nm, more preferably less than 30 nm, and less than 10 nm. More preferably, the thickness is less than 5 nm. By making the layer thickness less than 50 nm, optical loss can be minimized. On the other hand, the lower limit of the layer thickness is preferably 0.05 nm or more, more preferably 0.1 nm or more, and particularly preferably 0.3 nm or more. By setting the layer thickness to 0.05 nm or more, it is possible to make the underlayer 101a uniform, and to make the effect (inhibition of silver aggregation) uniform.

When the underlayer 101a is made of a high refractive index material (refractive index of 1.7 or more), the upper limit of the layer thickness is not particularly limited, and the lower limit of the layer thickness is the same as that of the low refractive index material. is there.

However, as a simple function of the base layer 101a, it is sufficient that the base layer 101a is formed with a necessary layer thickness that enables uniform film formation.

As a method for forming the base layer 101a, a wet process such as a coating method, an inkjet method, a coating method, or a dip method, or a dry process such as a vapor deposition method (resistance heating, EB method, etc.), a sputtering method, a CVD method, or the like is used. And the like. Among these, the vapor deposition method is preferably applied.

(2) Electrode layer The electrode layer 101b is preferably a layer formed using silver or an alloy containing silver as a main component, and is preferably a layer formed on the base layer 101a.

As a method for forming such an electrode layer 101b, a wet process such as a coating method, an inkjet method, a coating method, or a dip method, a vapor deposition method (resistance heating, EB method, etc.), a sputtering method, a CVD method, or the like is used. And a method using the dry process. Among these, the vapor deposition method is preferably applied.

In addition, the electrode layer 101b is formed on the base layer 101a, so that the electrode layer 101b has sufficient conductivity even without high-temperature annealing after the electrode layer 101b is formed. The film may be subjected to high-temperature annealing after film formation.

Examples of the alloy mainly composed of silver (Ag) constituting the electrode layer 101b include silver magnesium (AgMg), silver copper (AgCu), silver palladium (AgPd), silver palladium copper (AgPdCu), and silver indium (AgIn). ) And the like.

Further, it is also preferable to co-evaporate by adding about 2 atomic% of aluminum (Al) or gold (Au) to silver.

The electrode layer 101b as described above may have a configuration in which silver or an alloy layer mainly composed of silver is divided into a plurality of layers as necessary.

Furthermore, the electrode layer 101b preferably has a layer thickness in the range of 5 to 30 nm. When the layer thickness is less than 30 nm, the absorption component or reflection component of the layer is small, and the transmittance of the first transparent electrode 101 is increased. Moreover, when the layer thickness is thicker than 5 nm, the conductivity of the layer can be sufficiently secured. The range is preferably 8 to 20 nm, and more preferably 10 to 15 nm.

Note that the first transparent electrode 101 having a laminated structure composed of the base layer 101a and the electrode layer 101b formed thereon is covered with a protective film on the upper part of the electrode layer 101b or another electrode. Layers may be laminated. In this case, it is preferable that the protective film and the other electrode layer have light transmittance so as not to impair the light transmittance of the first transparent electrode 101.

(3) Effect of first transparent electrode The first transparent electrode 101 having the above-described configuration is, for example, an underlayer formed using an organic compound having at least one atom selected from a nitrogen atom and a sulfur atom. An electrode layer 101b made of silver or an alloy containing silver as a main component is provided on 101a. Thus, when the electrode layer 101b is formed on the base layer 101a, the silver atoms constituting the electrode layer 101b interact with the compound containing nitrogen atoms or sulfur atoms constituting the base layer 101a, and The diffusion distance of silver atoms is reduced on the surface of the base layer 101a, and aggregation of silver is suppressed.

Here, in general, in the film formation of the electrode layer 101b containing silver as a main component, a thin film is grown in a nucleus growth type (Volume-Weber: VW type), and therefore, silver particles are easily isolated in an island shape, and the layer thickness is increased. When the thickness is thin, it is difficult to obtain conductivity, and the sheet resistance value becomes high. Therefore, although it is necessary to increase the layer thickness in order to ensure conductivity, it is difficult to use as the first transparent electrode because the light transmittance decreases as the layer thickness increases.

However, as described above, since aggregation of silver is suppressed on the base layer 101a, the electrode layer 101b made of silver or an alloy containing silver as a main component is not a nucleus growth type but a single layer growth type ( A thin film grows with a Frank-van der Merwe (FM type).

The first transparent electrode 101 is preferably a transparent electrode having a light transmittance of 50% or more at a light wavelength of 550 nm, and an electrode layer made of silver or an alloy containing silver as a main component by providing the base layer 101a. 101b can be thinned and can be a film with sufficiently good light transmittance. On the other hand, the conductivity of the first transparent electrode 101 is mainly ensured by the electrode layer 101b. The electrode layer 101b made of silver or an alloy containing silver as a main component has excellent conductivity, and conductivity is ensured with a thinner layer thickness. Accordingly, it is possible to achieve both the improvement of the conductivity of the first transparent electrode 101 and the improvement of the light transmittance.

Furthermore, since the first transparent electrode according to the present invention can be adjusted to a thin film within a range in which specular light reflection at the silver electrode does not occur, it can contribute to an improvement in light emission luminance.

(Organic light emitting layer)
(1) Light emitting layer The organic light emitting layer 103 includes at least a light emitting layer 103c.

The phosphor layer 103c used in the present invention preferably contains a phosphorescent compound as a luminescent material. Note that a fluorescent material may be used as the light emitting material, or a phosphorescent light emitting compound and a fluorescent material may be used in combination.

The light emitting layer 103c is a layer that emits light by recombination of electrons injected from the electrode or the electron transport layer 103d and holes injected from the hole transport layer 103b, and the light emitting portion is the light emitting layer 103c. Even within the layer, it may be an interface between the light emitting layer 103c and the adjacent layer.

The structure of the light emitting layer 103c is not particularly limited as long as the included light emitting material satisfies the light emission requirements. Moreover, there may be a plurality of layers having the same emission spectrum and emission maximum wavelength. In this case, a non-light emitting intermediate layer (not shown) is preferably provided between the light emitting layers 103c.

The total thickness of the light emitting layer 103c is preferably in the range of 1 to 100 nm, and more preferably in the range of 1 to 30 nm because a lower driving voltage can be obtained.

Note that the sum of the layer thicknesses of the light emitting layer 103c is a layer thickness including the intermediate layer when a non-light emitting intermediate layer exists between the light emitting layers 103c.

In the case of the light emitting layer 103c having a structure in which a plurality of layers are stacked, the thickness of each light emitting layer is preferably adjusted within a range of 1 to 50 nm, and more preferably adjusted within a range of 1 to 20 nm. preferable. When the plurality of stacked light emitting layers correspond to blue, green, and red light emission colors, there is no particular limitation on the relationship between the thicknesses of the blue, green, and red light emitting layers.

The light emitting layer 103c as described above is formed by forming a known light emitting material or host compound by a known thin film forming method such as a vacuum deposition method, a spin coating method, a casting method, an LB method, or an ink jet method. be able to.

A light-emitting dopant (also referred to as a light-emitting dopant compound) and a host compound contained in the light-emitting layer will be described.

(1-1) Host Compound Here, in the present invention, the host compound means that the compound contained in the light emitting layer has a mass ratio of 20% or more in the layer and is phosphorus at room temperature (25 ° C.). A compound having a phosphorescence quantum yield of photoluminescence of less than 0.1 is defined. The phosphorescence quantum yield is preferably less than 0.01. Moreover, it is preferable that the mass ratio in the layer is 20% or more among the compounds contained in a light emitting layer.

As the host compound, known host compounds may be used alone or in combination of two or more. By using a plurality of types of host compounds, it is possible to adjust the movement of charges, and the organic EL element can be made highly efficient. Moreover, it becomes possible to mix different light emission by using multiple types of light emission dopants mentioned later, and, thereby, arbitrary luminescent colors can be obtained.

The light emitting host used in the present invention may be a conventionally known low molecular compound or a high molecular compound having a repeating unit, and a low molecular compound having a polymerizable group such as a vinyl group or an epoxy group (deposition polymerization property). Light emitting host).

As the known host compound that may be used in combination, a compound that has a hole transporting ability and an electron transporting ability, prevents the emission of light from being increased in wavelength, and has a high Tg (glass transition temperature) is preferable.

Specific examples of known host compounds include compounds described in the following documents, but are not limited thereto.

JP-A-2001-257076, 2002-308855, 2001-313179, 2002-319491, 2001-357777, 2002-334786, 2002-8860, 2002-334787, 2002-15871, 2002-334788, 2002-43056, 2002-334789, 2002-75645, 2002-338579, 2002-105445, 2002-343568, 2002-141173, 2002-352957, 2002-203683, 2002-363227, 2002-231453, 2003-3165, 2002-234888, 2003-27048, 2002-255934, 2002-260861, 2002-280183, 2002-299060, 2002 -302516, 2002-305083, 2002-305084, 2002-308837, and the like.

(1-2) Luminescent dopant The luminescent dopant used in the present invention will be described.

From the viewpoint of obtaining an organic EL device with higher luminous efficiency, the light emitting layer of the organic EL device of the present invention preferably contains a phosphorescent dopant at the same time as containing the host compound.

(1-3) Phosphorescent dopant The phosphorescent dopant used in the present invention is a compound in which light emission from an excited triplet is observed, specifically, a compound that emits phosphorescence at room temperature (25 ° C.). Yes, the phosphorescence quantum yield is defined to be a compound of 0.01 or more at 25 ° C., but the preferred phosphorescence quantum yield is 0.1 or more.

The phosphorescent quantum yield can be measured by the method described in Spectroscopic II, page 398 (1992 edition, Maruzen) of the Fourth Edition Experimental Chemistry Course 7. Although the phosphorescence quantum yield in a solution can be measured using various solvents, the phosphorescence dopant according to the present invention achieves the phosphorescence quantum yield (0.01 or more) in any solvent. That's fine.

There are two types of light emission of phosphorescent dopants in principle. One is the recombination of carriers on the host compound to which carriers are transported to generate an excited state of the host compound, and this energy is transferred to the phosphorescent dopant. The energy transfer type that obtains light emission from the phosphorescent dopant, and the other is that the phosphorescent dopant becomes a carrier trap, carrier recombination occurs on the phosphorescent dopant, and light emission from the phosphorescent dopant is obtained. Although it is a trap type, in any case, the excited state energy of the phosphorescent dopant is required to be lower than the excited state energy of the host compound.

Specific examples of known phosphorescent dopants that can be used in the present invention include compounds described in the following documents.

Nature 395, 151 (1998), Appl. Phys. Lett. 78, 1622 (2001), Adv. Mater. 19, 739 (2007), Chem. Mater. 17, 3532 (2005), Adv. Mater. 17, 1059 (2005), International Publication No. 2009/100991, International Publication No. 2008/101842, International Publication No. 2003/040257, US Patent Application Publication No. 2006/835469, US Patent Application Publication No. 2006 / No. 0202194, U.S. Patent Application Publication No. 2007/0087321, U.S. Patent Application Publication No. 2005/0244673, Inorg. Chem. 40, 1704 (2001), Chem. Mater. 16, 2480 (2004), Adv. Mater. 16, 2003 (2004), Angew. Chem. Lnt. Ed. 2006, 45, 7800, Appl. Phys. Lett. 86, 153505 (2005), Chem. Lett. 34, 592 (2005), Chem. Commun. 2906 (2005), Inorg. Chem. 42, 1248 (2003), International Publication No. 2009/050290, International Publication No. 2002/015645, International Publication No. 2009/000673, US Patent Application Publication No. 2002/0034656, and US Pat. No. 7,332,232. US Patent Application Publication No. 2009/0108737, US Patent Application Publication No. 2009/0039776, US Patent No. 6921915, US Patent No. 6,687,266, US Patent Application Publication No. 2007/0190359. Specification, US Patent Application Publication No. 2006/0008670, US Patent Application Publication No. 2009/0165846, US Patent Application Publication No. 2008/0015355, US Patent No. 7250226, US Patent No. 7396598 Specification, U.S. Patent Application Publication No. 2006/0263635, U.S. Patent Application Publication No. 2003/0138657, U.S. Patent Application Publication No. 2003/0152802, U.S. Patent No. 7090928, Angew. Chem. Lnt. Ed. 47, 1 (2008), Chem. Mater. 18, 5119 (2006), Inorg. Chem. 46, 4308 (2007), Organometallics 23, 3745 (2004), Appl. Phys. Lett. 74, 1361 (1999), International Publication No. 2002/002714, International Publication No. 2006/009024, International Publication No. 2006/056418, International Publication No. 2005/019373, International Publication No. 2005/123873, International Publication No. 2005/123873, International Publication No. 2007/004380, International Publication No. 2006/082742, US Patent Application Publication No. 2006/0251923, US Patent Application Publication No. 2005/0260441, US Pat. No. 7,393,599. Description, US Pat. No. 7,534,505, US Pat. No. 7,445,855, US Patent Application Publication No. 2007/0190359, US Patent Application Publication No. 2008/0297033, US Pat. No. 7,338,722 , National Patent Application Publication No. 2002/0134984, U.S. Patent No. 7279704, U.S. Patent Application Publication No. 2006/098120, U.S. Patent Application Publication No. 2006/103874, International Publication No. 2005/076380. No., International Publication No. 2010/032663, International Publication No. 2008/140115, International Publication No. 2007/052431, International Publication No. 2011/134013, International Publication No. 2011/157339, International Publication No. 2010/086089, International Publication No. 2009/113646, International Publication No. 2012/020327, International Publication No. 2011/051404, International Publication No. 2011/004639, International Publication No. 2011/073149, US Patent Application Publication No. 2012/2285853 book US Patent Application Publication No. 2012/212126, JP2012-069737, JP2011-181303, JP2009-1114086, JP2003-81988, JP2002-302671 For example, Japanese Patent Laid-Open No. 2002-363552.

Among these, a preferable phosphorescent dopant includes an organometallic complex having Ir as a central metal. More preferably, a complex containing at least one coordination mode among a metal-carbon bond, a metal-nitrogen bond, a metal-oxygen bond, and a metal-sulfur bond is preferable.

In the organic EL element 100, at least one light emitting layer 103c may contain two or more types of phosphorescent compounds, and the concentration ratio of the phosphorescent compounds in the light emitting layer 103c is the thickness of the light emitting layer 103c. It may change in direction.

The phosphorescent compound is preferably 0.1% by volume or more and less than 30% by volume with respect to the total amount of the light emitting layer 103c.

(1-4) Fluorescent compounds Fluorescent compounds include coumarin dyes, pyran dyes, cyanine dyes, croconium dyes, squalium dyes, oxobenzanthracene dyes, fluorescein dyes, rhodamine dyes, pyrylium dyes. Examples thereof include dyes, perylene dyes, stilbene dyes, polythiophene dyes, and rare earth complex phosphors.

(2) Injection layer (hole injection layer, electron injection layer)
The injection layer is a layer provided between the electrode and the light-emitting layer 103c in order to lower the drive voltage and improve the light emission luminance. “The organic EL element and its forefront of industrialization (November 30, 1998, NT. 2) Chapter 2 “Electrode Materials” (pages 123 to 166) of “S. Co., Ltd.”), which includes a hole injection layer 103a and an electron injection layer 103e.

The injection layer can be provided as necessary. The hole injection layer 103a may exist between the anode and the light emitting layer 103c or the hole transport layer 103b, and the electron injection layer 103e may exist between the cathode and the light emitting layer 103c or the electron transport layer 103d.

Details of the hole injection layer 103a are described in JP-A-9-45479, JP-A-9-260062, JP-A-8-288069, and the like. Specific examples include phthalocyanine represented by copper phthalocyanine. Examples thereof include a layer, an oxide layer typified by vanadium oxide, an amorphous carbon layer, and a polymer layer using a conductive polymer such as polyaniline (emeraldine) or polythiophene.

The details of the electron injection layer 103e are described in JP-A-6-325871, JP-A-9-17574, JP-A-10-74586, and the like, and specifically represented by strontium, aluminum and the like. Examples thereof include a metal layer, an alkali metal halide layer typified by potassium fluoride, an alkaline earth metal compound layer typified by magnesium fluoride, and an oxide layer typified by molybdenum oxide. The electron injection layer 103e of the present invention is desirably a very thin film, and the layer thickness is preferably in the range of 1 nm to 10 μm although it depends on the material.

(3) Hole transport layer The hole transport layer 103b is made of a hole transport material having a function of transporting holes, and in a broad sense, the hole injection layer 103a and the electron blocking layer are also included in the hole transport layer 103b. . The hole-transport layer 103b can be provided as a single layer or a plurality of layers.

The hole transport material has any of hole injection or transport and electron barrier properties, and may be either organic or inorganic. For example, triazole derivatives, oxadiazole derivatives, imidazole derivatives, polyarylalkane derivatives, pyrazoline derivatives and pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, Examples thereof include stilbene derivatives, silazane derivatives, aniline copolymers, and conductive polymer oligomers, particularly thiophene oligomers.

As the hole transport material, those described above can be used, but it is preferable to use a porphyrin compound, an aromatic tertiary amine compound and a styrylamine compound, particularly an aromatic tertiary amine compound.

Representative examples of aromatic tertiary amine compounds and styrylamine compounds include N, N, N ′, N′-tetraphenyl-4,4′-diaminophenyl; N, N′-diphenyl-N, N′— Bis (3-methylphenyl)-[1,1′-biphenyl] -4,4′-diamine (TPD); 2,2-bis (4-di-p-tolylaminophenyl) propane; 1,1-bis (4-di-p-tolylaminophenyl) cyclohexane; N, N, N ′, N′-tetra-p-tolyl-4,4′-diaminobiphenyl; 1,1-bis (4-di-p-tolyl) Aminophenyl) -4-phenylcyclohexane; bis (4-dimethylamino-2-methylphenyl) phenylmethane; bis (4-di-p-tolylaminophenyl) phenylmethane; N, N'-diphenyl-N, N ' Di (4-methoxyphenyl) -4,4'-diaminobiphenyl; N, N, N ', N'-tetraphenyl-4,4'-diaminodiphenyl ether; 4,4'-bis (diphenylamino) quadriphenyl N, N, N-tri (p-tolyl) amine; 4- (di-p-tolylamino) -4 '-[4- (di-p-tolylamino) styryl] stilbene; 4-N, N-diphenylamino -(2-diphenylvinyl) benzene; 3-methoxy-4'-N, N-diphenylaminostilbenzene; N-phenylcarbazole and also two condensed aromatics described in US Pat. No. 5,061,569 Having a ring in the molecule, for example, 4,4'-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (NPD), JP-A-4-3086 4,4 ′, 4 ″ -tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine in which three triphenylamine units described in publication No. 8 are linked in three starburst types ( MTDATA) and the like.

Further, a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain can also be used. In addition, inorganic compounds such as p-type-Si and p-type-SiC can also be used as the hole injection material and the hole transport material.

Also, JP-A-11-251067, J. Org. Huang et. al. , Applied Physics Letters, 80 (2002), p. A so-called p-type hole transport material as described in 139 can also be used. In the present invention, it is preferable to use these materials because a light-emitting element with higher efficiency can be obtained.

The hole transport layer 103b is formed by thinning the hole transport material by a known method such as a vacuum deposition method, a spin coating method, a casting method, a printing method including an inkjet method, or an LB method. be able to. The layer thickness of the hole transport layer 103b is not particularly limited, but is usually about 5 nm to 5 μm, preferably 5 to 200 nm. The hole transport layer 103b may have a single layer structure composed of one or more of the above materials.

It is also possible to increase the p property by doping impurities into the material of the hole transport layer 103b. Examples thereof include JP-A-4-297076, JP-A-2000-196140, 2001-102175, J.A. Appl. Phys. 95, 5773 (2004), and the like.

Thus, it is preferable to increase the p property of the hole transport layer 103b because an element with lower power consumption can be manufactured.

(4) Electron Transport Layer The electron transport layer 103d is made of a material having a function of transporting electrons. In a broad sense, the electron injection layer 103e and a hole blocking layer (not shown) are also included in the electron transport layer 103d. The electron transport layer 103d can be provided as a single-layer structure or a stacked structure of a plurality of layers.

In the electron transport layer 103d having a single layer structure and the electron transport layer 103d having a multilayer structure, an electron transport material (also serving as a hole blocking material) constituting a layer portion adjacent to the light emitting layer 103c was injected from the cathode. What is necessary is just to have the function to transmit an electron to the light emitting layer 103c. As such a material, any one of conventionally known compounds can be selected and used. Examples include nitro-substituted fluorene derivatives, diphenylquinone derivatives, thiopyran dioxide derivatives, carbodiimides, fluorenylidenemethane derivatives, anthraquinodimethane, anthrone derivatives, and oxadiazole derivatives. Further, in the above oxadiazole derivative, a thiadiazole derivative in which the oxygen atom of the oxadiazole ring is substituted with a sulfur atom, and a quinoxaline derivative having a quinoxaline ring known as an electron-withdrawing group are also used as the material for the electron transport layer 103d. Can do. Furthermore, a polymer material in which these materials are introduced into a polymer chain or these materials are used as a polymer main chain can also be used.

In addition, metal complexes of 8-quinolinol derivatives such as tris (8-quinolinol) aluminum (Alq ₃ ), tris (5,7-dichloro-8-quinolinol) aluminum, tris (5,7-dibromo-8-quinolinol) Aluminum, tris (2-methyl-8-quinolinol) aluminum, tris (5-methyl-8-quinolinol) aluminum, bis (8-quinolinol) zinc (Znq), etc., and the central metals of these metal complexes are In, Mg Metal complexes replaced with Cu, Ca, Sn, Ga, or Pb can also be used as the material for the electron transport layer 103d.

In addition, metal-free or metal phthalocyanine, or those having terminal ends substituted with an alkyl group or a sulfonic acid group can be preferably used as the material for the electron transport layer 103d. Further, a distyrylpyrazine derivative exemplified also as a material of the light-emitting layer 103c can be used as a material of the electron-transport layer 103d, and n-type Si, n-type similarly to the hole-injection layer 103a and the hole-transport layer 103b. An inorganic semiconductor such as type-SiC can also be used as the material of the electron transport layer 103d.

The electron transport layer 103d can be formed by thinning the above material by a known method such as a vacuum deposition method, a spin coating method, a casting method, a printing method including an ink jet method, or an LB method. The layer thickness of the electron transport layer 103d is not particularly limited, but is usually about 5 nm to 5 μm, preferably 5 to 200 nm. The electron transport layer 103d may have a single-layer structure made of one or more of the above materials.

Further, the electron transport layer 103d can be doped with an impurity to increase the n property. Examples thereof include JP-A-4-297076, JP-A-10-270172, JP-A-2000-196140, 2001-102175, J.A. Appl. Phys. 95, 5773 (2004), and the like. Furthermore, it is preferable that the electron transport layer 103d contains potassium, a potassium compound, or the like. As the potassium compound, for example, potassium fluoride can be used. Thus, when the n property of the electron transport layer 103d is increased, a device with lower power consumption can be manufactured.

Further, as the material (electron transporting compound) of the electron transport layer 103d, the same material as that of the base layer 101a described above may be used. The same applies to the electron transport layer 103d that also serves as the electron injection layer 103e, and the same material as that of the base layer 101a described above may be used.

(5) Blocking layer (hole blocking layer, electron blocking layer)
The blocking layer may be further provided as the organic light emitting layer 103 in addition to the above functional layers. For example, it is described in JP-A Nos. 11-204258 and 11-204359, and “Organic EL elements and the forefront of industrialization (published by NTT Corporation on November 30, 1998)” on page 237. There is a hole blocking (hole blocking) layer.

The hole blocking layer has a function of the electron transport layer 103d in a broad sense. The hole blocking layer is made of a hole blocking material that has a function of transporting electrons but has a very small ability to transport holes, and recombines electrons and holes by blocking holes while transporting electrons. Probability can be improved. Moreover, the structure of the electron carrying layer 103d mentioned later can be used as a hole-blocking layer concerning this invention as needed. The hole blocking layer is preferably provided adjacent to the light emitting layer 103c.

On the other hand, the electron blocking layer has the function of the hole transport layer 103b in a broad sense. The electron blocking layer is made of a material that has a function of transporting holes but has a very small ability to transport electrons, and improves the probability of recombination of electrons and holes by blocking electrons while transporting holes. be able to. Further, the structure of the hole transport layer 103b can be used as an electron blocking layer as necessary. The layer thickness of the hole blocking layer according to the present invention is preferably in the range of 3 to 100 nm, more preferably in the range of 5 to 30 nm.

Film formation of each of the hole injection layer 103a, the hole transport layer 103b, the light emitting layer 103c, the electron transport layer 103d, and the electron injection layer 103e described above is performed by a spin coating method, a casting method, an ink jet method, an evaporation method, and a printing method. However, the vacuum deposition method or the spin coating method is particularly preferable from the viewpoints that a homogeneous film is easily obtained and pinholes are hardly generated. Further, different film formation methods may be applied for each layer. When a vapor deposition method is employed for forming each of these layers, the vapor deposition conditions vary depending on the type of compound used, but generally the boat heating temperature is in the range of 50 to 450 ° C. and the degree of vacuum is 1 × 10 ⁻⁶ to 1 × 10. It is desirable to select each condition as appropriate within a range of ⁻² Pa, a deposition rate of 0.01 to 50 nm / second, a substrate temperature of −50 to 300 ° C., and a layer thickness of 0.1 to 5 μm.

[Second transparent electrode (counter electrode)]
The second transparent electrode 102 is an electrode film that functions as a cathode for supplying electrons to the organic light emitting layer 103, and a metal, an alloy, an organic or inorganic conductive compound, and a mixture thereof are used.

The 2nd transparent electrode 102 can use all the electrodes which can be normally used for an organic EL element like the 1st transparent electrode. Specifically, aluminum, silver, magnesium, lithium, magnesium / same mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, indium, lithium / aluminum mixture, rare earth metal, ITO, ZnO, TiO ₂ , An oxide semiconductor such as SnO ₂ can be given.

Among these, like the first transparent electrode 101, the second transparent electrode 102 is preferably a layer composed of silver or an alloy containing silver as a main component.

As a method for forming the second transparent electrode 102, a method using a wet process such as a coating method, an inkjet method, a coating method, a dip method, a vapor deposition method (resistance heating, EB method, etc.), a sputtering method, a CVD method, or the like. And a method using a dry process such as a method. Among these, the vapor deposition method is preferably applied.

Examples of the alloy mainly composed of silver (Ag) constituting the second transparent electrode 102 include silver magnesium (AgMg), silver copper (AgCu), silver palladium (AgPd), silver palladium copper (AgPdCu), and silver indium. (AgIn) etc. are mentioned.

The second transparent electrode 102 as described above may have a configuration in which silver or an alloy layer mainly composed of silver is divided into a plurality of layers as necessary.

Furthermore, the second transparent electrode 102 preferably has a layer thickness in the range of 5 to 30 nm. When the layer thickness is less than 30 nm, the absorption component or reflection component of the layer is small, and the transmittance of the second transparent electrode 102 is increased. Moreover, when the layer thickness is thicker than 5 nm, the conductivity of the layer can be sufficiently secured. The range is preferably 8 to 20 nm, and more preferably 10 to 15 nm.

[Extraction electrode (not shown)]
The extraction electrode is for electrically connecting the first transparent electrode 101 and the second transparent electrode 102 and an external power source, and the material thereof is not particularly limited, and a known material can be suitably used. For example, a metal film such as a MAM electrode (Mo / Al · Nd alloy / Mo) having a three-layer structure can be used.

[Auxiliary electrode (not shown)]
The auxiliary electrode is provided for the purpose of reducing the resistance of the first transparent electrode 101 and the second transparent electrode 102, and is provided in contact with the electrode layer 101 b of the first transparent electrode 101 and the electrode layer of the second transparent electrode 102. . The material for forming the auxiliary electrode is preferably a metal having low resistance such as gold, platinum, silver, copper, or aluminum. Since these metals have low light transmittance, a pattern is formed in a range not affected by extraction of the emitted light h from the light extraction surface.

Examples of methods for forming such auxiliary electrodes include vapor deposition, sputtering, printing, ink jet, and aerosol jet. The line width of the auxiliary electrode is preferably 50 μm or less from the viewpoint of the aperture ratio for extracting light, and the thickness of the auxiliary electrode is preferably 1 μm or more from the viewpoint of conductivity.

(Electrode protective layer)
In the present invention, an electrode protective layer 104 containing an organic or inorganic compound is formed between the second transparent electrode 102 and the transparent sealing substrate 105 to smooth the surface of the second transparent electrode. And is sufficient for sufficient mechanical protection. In addition, by containing an organic or inorganic compound, when the transparent sealing substrate 105 is laminated, since it is solid-sealed, the adhesive strength is high.

The electrode protective layer 104 as described above preferably has flexibility, and a thin polymer film or a thin metal film can be used. The organic compound used in the base layer or the organic light emitting layer can be used. It is also preferable that the layer is appropriately selected and formed by the coating method or the vapor deposition method.

The electrode protective layer according to the present invention preferably contains a metal oxide from the viewpoint of solid sealing, and specific examples of the metal oxide include molybdenum oxide.

The preferred thickness of the electrode protective layer according to the present invention can be appropriately set according to the purpose, but is preferably about 10 nm to 10 μm, more preferably about 15 nm to 1 μm, and more preferably 20 to 500 nm. More preferably, it is the range.

(Transparent sealing substrate)
The transparent sealing substrate 105 according to the present invention has a function of laminating and sealing the organic EL element 100, and as shown in the illustrated example, for example, an adhesive layer containing an adhesive (not shown) By this, it is fixed to the electrode protective layer 104 side and the substrate 110 side. Such a transparent sealing substrate 105 is provided in a state in which the terminal portions of the first transparent electrode 101 and the second transparent electrode 102 in the organic EL element 100 are exposed and at least the organic light emitting layer 103 is completely covered.

The transparent sealing substrate 105 according to the present invention preferably has flexibility and preferably has gas barrier properties.

The transparent sealing substrate 105 is preferably composed of a transparent resin substrate as a support and one or more gas barrier layers.

The transparent sealing substrate 105 is a conventionally known substrate, for example, acrylic resins such as acrylic ester, methacrylic ester, PMMA, polyethylene terephthalate (PET), polybutylene terephthalate, polyethylene naphthalate (PEN), polycarbonate. (PC), polyarylate, polyvinyl chloride (PVC), polyethylene (PE), polypropylene (PP), polystyrene (PS), nylon (Ny), aromatic polyamide, polyether ether ketone, polysulfone, polyether sulfonate, polyimide , Polyetherimide, polyolefin, epoxy resin, and the like, and cycloolefin-based and cellulose ester-based films can also be used. In addition, a heat-resistant transparent film (product name: Sila-DEC, manufactured by Chisso Corporation) having silsesquioxane having an organic-inorganic hybrid structure as a basic skeleton, and a resin film obtained by laminating two or more layers of the resin material, etc. Can be mentioned.

As with the substrate 110, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polycarbonate (PC), acrylic resin, and the like are preferably used from the viewpoint of cost and availability.

The thickness of the transparent resin substrate is preferably in the range of 10 to 500 μm, more preferably in the range of 20 to 250 μm, and still more preferably in the range of 30 to 150 μm. When the thickness of the resin base material is in the range of 10 to 500 μm, a stable gas barrier property can be obtained, and the resin base material is suitable for conveyance in a roll-to-roll system.

The gas barrier layer is not particularly limited, but preferably has at least one inorganic layer on the resin substrate from the viewpoint of controlling the average refractive index in the range of 1.50 to 2.50 for light extraction. The gas barrier layer is preferably a gas barrier layer coated with a coating solution containing a precursor compound and then subjected to a modification treatment by irradiation with vacuum ultraviolet rays. Especially, it is preferable that it is the layer which apply | coated the coating liquid containing the polysilazane used for the said smooth layer, and modify-processed to silicon oxide by vacuum ultraviolet irradiation. As a method for forming the layer modified with silicon oxide, the method described in the section of the smooth layer can be used.

<Sealing (laminate) method>
The method of sealing (laminating) with the transparent sealing substrate 105 is not particularly limited. For example, the organic EL element 100 is subjected to an environment in which oxygen and moisture concentration are constant (for example, oxygen concentration of 10 ppm or less, moisture concentration). The organic EL element is formed by an adhesive layer formed on the transparent sealing substrate 105 by placing it under a reduced pressure (1 × 10 ⁻³ MPa or less) and applying pressure while applying suction. 100 is laminated, and then the adhesive layer is thermally cured by heating with a hot air circulation oven, an infrared heater, a heat gun, a high frequency induction heating device, a heat tool, or the like.

There are no particular restrictions on the adhesive, but specific examples include various thermosetting resins such as epoxy resins, cyanate ester resins, phenol resins, bismaleimide-triazine resins, polyimide resins, acrylic resins, and vinylbenzyl resins. preferable. Among these, an epoxy resin is preferable from the viewpoint of low-temperature curability and adhesiveness.

As an epoxy resin, those having an average of two or more epoxy groups per molecule may be used. Specifically, bisphenol A type epoxy resin, biphenyl type epoxy resin, biphenyl aralkyl type epoxy resin, and naphthol type epoxy are used. Resin, naphthalene type epoxy resin, bisphenol F type epoxy resin, phosphorus-containing epoxy resin, bisphenol S type epoxy resin, aromatic glycidylamine type epoxy resin (specifically, tetraglycidyldiaminodiphenylmethane, triglycidyl-p-aminophenol, Diglycidyl toluidine, diglycidyl aniline, etc.), alicyclic epoxy resin, aliphatic chain epoxy resin, phenol novolac epoxy resin, cresol novolac epoxy resin, bisphenol A novolac epoxy resin , Epoxy resin having a butadiene structure, phenol aralkyl type epoxy resin, epoxy resin having a dicyclopentadiene structure, diglycidyl etherified product of bisphenol, diglycidyl etherified product of naphthalenediol, glycidyl etherified product of phenol, and diester of alcohol Examples thereof include glycidyl etherified products, and alkyl-substituted products, halides, and hydrogenated products of these epoxy resins. These may be used alone or in combination of two or more.

Among these, bisphenol A type epoxy resin, bisphenol F type epoxy resin, phenol novolac type epoxy resin, biphenyl aralkyl type epoxy resin, phenol aralkyl type epoxy from the viewpoint of maintaining high heat resistance and low moisture permeability of the resin composition. A resin, an aromatic glycidylamine type epoxy resin, an epoxy resin having a dicyclopentadiene structure, and the like are preferable.

The epoxy resin may be liquid, solid, or both liquid and solid. Here, “liquid” and “solid” are states of the epoxy resin at 25 ° C. From the viewpoints of coatability, processability, adhesiveness, and the like, it is preferable that 10% by mass or more of the entire epoxy resin to be used is liquid.

The epoxy resin preferably has an epoxy equivalent in the range of 100 to 1000, more preferably in the range of 120 to 1000, from the viewpoint of reactivity. Here, the epoxy equivalent is the number of grams (g / eq) of a resin containing 1 gram equivalent of an epoxy group, and is measured according to the method defined in JIS K-7236.

The curing agent for the epoxy resin is not particularly limited as long as it has a function of curing the epoxy resin, but from the viewpoint of suppressing thermal deterioration of the element (particularly the organic EL element) during the curing treatment of the resin composition. The curing treatment of the composition is preferably performed at 140 ° C. or lower, more preferably 120 ° C. or lower, and the curing agent preferably has an epoxy resin curing action in such a temperature range.

Specific examples include primary amines, secondary amines, tertiary amine-based curing agents, polyaminoamide-based curing agents, dicyandiamide, and organic acid dihydrazides. Among these, amine adduct-based compounds ( Amicure PN-23, Amicure MY-24, Amicure PN-D, Amicure MY-D, Amicure PN-H, Amicure MY-H, Amicure PN-31, Amicure PN-40, Amicure PN-40J, etc. (all Ajinomoto Fine Techno)), organic acid dihydrazide (Amicure VDH-J, Amicure UDH, Amicure LDH, etc. (all manufactured by Ajinomoto Fine Techno Co.)) and the like are preferable. These may be used alone or in combination of two or more.

The epoxy resin has extremely good low-temperature curability, and the upper limit of the curing temperature is preferably 140 ° C. or less, more preferably 120 ° C. or less, and even more preferably 110 ° C. or less. On the other hand, from the viewpoint of securing the adhesiveness of the cured product, the lower limit of the curing temperature is preferably 50 ° C. or higher, and more preferably 55 ° C. or higher. Moreover, 120 minutes or less is preferable, as for the upper limit of hardening time, 90 minutes or less are more preferable, and 60 minutes or less are still more preferable. On the other hand, from the viewpoint of surely curing the cured product, the lower limit of the curing time is preferably 20 minutes or more, and more preferably 30 minutes or more. Thereby, the thermal deterioration of the organic EL element can be extremely reduced.

≪Use of organic EL elements≫
The organic EL element of the present invention is a surface light emitter and can be used as various light sources. For example, lighting devices such as home lighting and interior lighting, backlights for watches and liquid crystals, lighting for billboard advertisements, light sources for traffic lights, light sources for optical storage media, light sources for electrophotographic copying machines, light sources for optical communication processors, It can be used as a light source for an optical sensor.

In particular, the organic EL element of the present invention may be used as a kind of lamp such as an illumination or exposure light source, a projection device that projects an image, or a type that directly recognizes a still image or a moving image. It may be used as a display device (display). In particular, since the organic EL element of the present invention is a top emission type, when used in a display device, the contrast is high and excellent display performance can be realized.

The drive method when used as a display device for moving image reproduction may be either a simple matrix (passive matrix) method or an active matrix method. In addition, a color or full-color display device can be manufactured by using two or more organic EL elements of the present invention having different emission colors.

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In addition, although the display of "part" or "%" is used in an Example, unless otherwise indicated, "part by mass" or "mass%" is represented.

Example 1
[Production of Organic EL Element 101]
(Production of substrate)
A polyester film having a thickness of 125 μm (manufactured by Teijin DuPont Films Ltd., extremely low heat yield PET) is put into a vacuum tank equipped with a resistance heating boat made of tungsten containing aluminum (Al), and the degree of vacuum is 4 × 10 ^{−. The} pressure was reduced to ⁴ Pa, and an aluminum (Al) layer having a layer thickness of 25 μm was deposited on a PET film at a deposition rate of 0.3 to 0.5 nm / second to produce a light reflective substrate.

The substrate has an oxygen permeability measured by a method according to JIS K 7126-1987 of 1 × 10 ⁻³ ml / m ² · 24 h · atm or less, and a water vapor permeability of 1 × 10 ⁻⁵ g / m. it was confirmed that the following gas-barrier substrate ² · 24h.

(Formation of functional layer containing white pigment)
As a functional layer containing a white pigment, a light diffusing reflection layer containing a white pigment was formed using the following coating solution.

<Preparation of coating liquid A>
Barium sulfate (trade name B-54: Sakai Chemical Industry Co., Ltd.) is applied to a urethane-based polyester polyol resin (trade name Barnock D6-439: DIC Corporation) having a shore hardness of 5-7. Pigment: resin = 6: 1 (mass ratio) To prepare a coating solution A.

The coating solution A is coated on the aluminum (Al) layer of the substrate with a wire bar so that the dry coating film becomes 50 μm, and dried at 80 ° C. to contain a white pigment. A light diffuse reflection layer was formed.

The relative diffuse reflectance of the formed light diffusive reflective layer containing the white pigment was 95% on average in the light wavelength region of 380 to 550 nm. The measurement was performed using a Hitachi spectrophotometer U-4100.

(Formation of first transparent electrode)
A 150 nm thick ITO (Indium Tin Oxide: ITO) film is formed on the formed light diffusive reflection layer by a sputtering method using a commercially available sputtering apparatus, and patterned by a photolithography method. A first transparent electrode was formed. The pattern was such that the light emission area was 50 mm square.

(Formation of organic light emitting layer)
(Formation of hole transport layer)
On the first transparent electrode, the following coating solution for forming a hole transport layer is applied with a spin coater in an environment of 25 ° C. and a relative humidity of 50% RH, and then dried and heated under the following conditions. And a hole transport layer was formed. The coating solution for forming the hole transport layer was applied so that the thickness after drying was 50 nm.

<Preparation of hole transport layer forming coating solution>
A solution prepared by diluting polyethylene dioxythiophene / polystyrene sulfonate (PEDOT / PSS, Baytron P AI 4083 manufactured by Bayer) with pure water at 65% and methanol at 5% was prepared as a coating solution for forming a hole transport layer.

<Drying and heat treatment conditions>
After applying the hole transport layer forming coating solution, the solvent is removed at a height of 100 mm toward the film formation surface, a discharge air velocity of 1 m / s, a wide air velocity distribution of 5%, and a temperature of 100 ° C., followed by heat treatment. The back surface heat transfer type heat treatment was performed at a temperature of 150 ° C. using an apparatus to form a hole transport layer.

(Formation of light emitting layer)
On the hole transport layer formed above, the following coating solution for forming a white light emitting layer was applied with a spin coater under the following conditions, followed by drying and heat treatment under the following conditions to form a light emitting layer. . The white light emitting layer forming coating solution was applied so that the thickness after drying was 40 nm.

<White luminescent layer forming coating solution>
As a host material, 1.0 g of a compound represented by the following chemical formula HA, 100 mg of a compound represented by the following chemical formula DA as a dopant material, and 0.1 mg of a compound represented by the following chemical formula DB as a dopant material. 2 mg of a compound represented by the following chemical formula DC as a dopant material was dissolved in 0.2 mg and 100 g of toluene to prepare a white light emitting layer forming coating solution.

<Application conditions>
The coating process was performed in an atmosphere having a nitrogen gas concentration of 99% or more, and the coating temperature was 25 ° C.

<Drying and heat treatment conditions>
After applying the white light emitting layer forming coating solution, the solvent was removed at a height of 100 mm toward the film formation surface, a discharge wind speed of 1 m / s, a wide wind speed distribution of 5%, and a temperature of 60 ° C., and then a temperature of 130 ° C. A heat treatment was performed to form a light emitting layer.

(Formation of electron transport layer)
On the light emitting layer formed above, the following coating liquid for forming an electron transport layer was applied with a spin coater under the following conditions, and then dried and heated under the following conditions to form an electron transport layer. The coating solution for forming an electron transport layer was applied so that the thickness after drying was 30 nm.

<Application conditions>
The coating process was performed in an atmosphere with a nitrogen gas concentration of 99% or more, and the coating temperature of the electron transport layer forming coating solution was 25 ° C.

<Coating liquid for electron transport layer formation>
The electron transport layer was prepared by dissolving a compound represented by the following chemical formula EA in 2,2,3,3-tetrafluoro-1-propanol to obtain a 0.5 mass% solution as a coating solution for forming an electron transport layer.

<Drying and heat treatment conditions>
After applying the electron transport layer forming coating solution, the solvent is removed at a height of 100 mm toward the film formation surface, a discharge wind speed of 1 m / s, a wide wind speed distribution of 5%, and a temperature of 60 ° C. Then, heat treatment was performed at a temperature of 200 ° C. to form an electron transport layer.

(Formation of electron injection layer)
An electron injection layer was formed on the electron transport layer formed above. First, the substrate was put into a vacuum chamber and the pressure was reduced to 5 × 10 ⁻⁴ Pa. In advance, cesium fluoride prepared in a tantalum vapor deposition boat was heated in a vacuum chamber to form an electron injection layer having a thickness of 3 nm.

(Formation of second transparent electrode)
Using ITO as the second transparent electrode forming material under the vacuum of 5 × 10 ⁻⁴ Pa on the electron injection layer formed as described above, except for the portion that becomes the extraction electrode of the first transparent electrode. Then, a mask pattern was formed by vapor deposition so as to have an extraction electrode so that the light emission area was 50 mm square, and a second transparent electrode having a thickness of 150 nm was laminated.

(Cutting)
As described above, each of the laminates formed up to the second transparent electrode was moved again to a nitrogen atmosphere, and cut to a prescribed size using an ultraviolet laser to produce an organic EL element.

(Electrode lead connection)
An anisotropic conductive film DP3232S9 manufactured by Sony Chemical & Information Device Co., Ltd. was used for the produced organic EL element, and a flexible printed board (base film: polyimide 12.5 μm, rolled copper foil 18 μm, coverlay: polyimide 12.5 μm). , Surface-treated NiAu plating).

Crimping conditions: Crimping was performed at a temperature of 170 ° C. (ACF temperature 140 ° C. measured using a separate thermocouple), a pressure of 2 MPa, and 10 seconds.

(Sealing)
The organic EL element 101 was produced using the following PET base material with a gas barrier layer as a transparent sealing base material. As the PET substrate, a 125 μm-thick polyester film (manufactured by Teijin DuPont Films Ltd., extremely low heat yield PET) was used.

Adhesion of the transparent sealing substrate using the PET substrate with the gas barrier layer uses an epoxy thermosetting adhesive (Elephan CS manufactured by Yodogawa Paper Co., Ltd.) as an adhesive, an oxygen concentration of 10 ppm or less, and a moisture concentration of 10 ppm. In the following glove box, under the conditions of 80 ° C., 0.04 MPa load, reduced pressure (1 × 10 ⁻³ MPa or less) suction 20 seconds, press 20 seconds, the PET base with a gas barrier layer toward the organic EL element Vacuum pressing was performed so that the gas barrier layer of the material was on the element side.

Then, in the glove box, the adhesive layer was thermally cured by heating on a hot plate at 110 ° C. for 30 minutes.

<PET substrate with gas barrier layer>
(Preparation of polysilazane-containing coating solution)
Dibutyl ether solution containing 20% by mass of non-catalytic perhydropolysilazane (manufactured by AZ Electronic Materials, Aquamica (registered trademark) NN120-20) and amine catalyst (N, N, N ′, N′-tetramethyl-) Perhydropolysilazane 20 mass% dibutyl ether solution (AZ Electronic Materials Co., Ltd., Aquamica (registered trademark) NAX120-20) containing 5 mass% of 1,6-diaminohexane (TMDAH) 4: 1 In a solvent mixed so that the mass ratio of dibutyl ether and 2,2,4-trimethylpentane was 65:35, the coating solution was mixed so that the solid content of the coating solution was 5% by mass. Was diluted and prepared.

The coating solution obtained above was formed into a film with a thickness of 300 nm on the PET substrate with a spin coater, allowed to stand for 2 minutes, and then subjected to a heat treatment for 1 minute on an 80 ° C. hot plate to obtain polysilazane. A coating film was formed.

After forming the polysilazane coating film, a gas barrier layer was formed by performing a vacuum ultraviolet ray irradiation treatment of 6000 mJ / cm ² according to the following method.

<Measurement of vacuum ultraviolet irradiation conditions and irradiation energy>
The vacuum ultraviolet irradiation was performed using the apparatus schematically shown in FIG.

In FIG. 3, reference numeral 201 denotes an apparatus chamber, which supplies appropriate amounts of nitrogen and oxygen from a gas supply port (not shown) to the inside and exhausts gas from a gas discharge port (not shown), thereby substantially removing water vapor from the inside of the chamber. The oxygen concentration can be maintained at a predetermined concentration. Reference numeral 202 denotes an Xe excimer lamp having a double tube structure that irradiates vacuum ultraviolet rays of 172 nm, and reference numeral 203 denotes an excimer lamp holder that also serves as an external electrode. Reference numeral 204 denotes a sample stage. The sample stage 204 can be reciprocated horizontally at a predetermined speed in the apparatus chamber 201 by a moving means (not shown). The sample stage 204 can be maintained at a predetermined temperature by a heating means (not shown). Reference numeral 205 denotes a sample on which a polysilazane coating film is formed. When the sample stage moves horizontally, the height of the sample stage is adjusted so that the shortest distance between the surface of the sample coating layer and the excimer lamp tube surface is 3 mm. Reference numeral 206 denotes a light shielding plate, which prevents the vacuum ultraviolet light from being applied to the coating layer of the sample during the aging of the Xe excimer lamp 202.

The energy irradiated on the coating film surface in the vacuum ultraviolet irradiation process was measured using a 172 nm sensor head using an ultraviolet integrated light meter manufactured by Hamamatsu Photonics Co., Ltd .: C8026 / H8025 UV POWER METER. In the measurement, the sensor head is installed in the center of the sample stage 204 so that the shortest distance between the Xe excimer lamp tube surface and the measurement surface of the sensor head is 3 mm, and the atmosphere in the apparatus chamber 201 is irradiated with vacuum ultraviolet rays. Nitrogen and oxygen were supplied so that the oxygen concentration was the same as in the process, and the sample stage 204 was moved at a speed of 0.5 m / min (V in FIG. 3) for measurement. Prior to measurement, in order to stabilize the illuminance of the Xe excimer lamp 202, an aging time of 10 minutes was provided after the Xe excimer lamp was turned on, and then the sample stage was moved to start the measurement.

Based on the irradiation energy obtained by this measurement, the irradiation speed was adjusted to 6000 mJ / cm ² by adjusting the moving speed of the sample stage. The vacuum ultraviolet irradiation was performed after aging for 10 minutes, similar to the measurement of irradiation energy.

[Production of Organic EL Element 102]
In the production of the organic EL element 101, the organic EL element 102 was produced in the same manner except that a smooth layer was provided between the functional layer containing the white pigment and the first transparent electrode.

(Smooth layer)
The following smooth layer having a layer thickness of 600 nm was formed on the functional layer containing the formed white pigment. When the surface roughness (arithmetic mean roughness Ra) of the smooth layer was measured, Ra = 5 nm.

<Formation of smooth layer>
The coating layer containing the following inorganic precursor compound is applied to the surface of the functional layer containing the formed white pigment by using a vacuum extrusion type coater so that the dry layer thickness is 150 nm. Was applied.

The coating solution containing the inorganic precursor compound is a non-catalytic perhydropolysilazane 20 mass% dibutyl ether solution (AZ Electronic Materials Co., Ltd. Aquamica NN120-20) and an amine catalyst containing 5 mass% solid content. Hydropolysilazane 20% by mass dibutyl ether solution (AZ Electronic Materials Co., Ltd. Aquamica NAX120-20) is used by mixing, adjusting the amine catalyst to 1% by mass of solid content, and further diluting with dibutyl ether This was prepared as a 5% by mass dibutyl ether solution.

After application, the substrate was dried with infrared rays under conditions of a substrate temperature of 80 ° C., a drying time of 5 minutes, and a dew point of 5 ° C. in a dry atmosphere.

After drying, the resin substrate was gradually cooled to 25 ° C., and the coating surface was subjected to modification treatment by irradiation with vacuum ultraviolet rays in a vacuum ultraviolet irradiation apparatus. As a light source of the vacuum ultraviolet irradiation device, an Xe excimer lamp having a double tube structure for irradiating vacuum ultraviolet rays of 172 nm was used.

<Modification processing equipment>
Excimer irradiation device MODEL: MECL-M-1-200, light wavelength 172 nm, lamp filled gas Xe
<Reforming treatment conditions>
Excimer light intensity 3J / cm ² (172nm)
Stage heating temperature 100 ° C
Oxygen concentration in the irradiation device 1000ppm
After the modification treatment, the second layer, the third layer, and the fourth layer were further laminated in the same manner, and the reaction of polysilazane was further advanced in an 80 ° C. Dry environment to form a smooth layer.

[Production of Organic EL Element 103]
The following aluminum (Al) layer was further formed on the PET film having the aluminum (Al) layer used in the production of the organic EL element 101, and the organic EL element 101 was similarly used except that it was used as a substrate having a specular light reflecting layer. A light-emitting element 103 was manufactured.

(Production of substrate)
The PET film having the aluminum (Al) layer used in the production of the organic EL element 101 is put into a vacuum tank equipped with a resistance heating boat made of tungsten containing aluminum (Al), and the degree of vacuum is 4 × 10 ⁻⁴ Pa. The substrate having a specular light reflectivity is formed by laminating an aluminum (Al) layer having a layer thickness of 300 nm on the aluminum (Al) layer of the PET film at a film forming speed of 0.3 to 0.5 nm / sec. Was made.

[Production of Organic EL Element 104]
An organic EL element except that a substrate on which an aluminum (Al) layer used in the production of the organic EL element 103 was laminated was used instead of the PET film having the aluminum (Al) layer used in the production of the organic EL element 102. The organic light emitting device 104 was produced in the same manner as the production of 102.

[Production of Organic EL Element 105]
In the production of the organic EL element 101, an organic EL element 105 was produced in the same manner except that the following black light absorption layer was formed as a functional layer.

(Formation of black light absorption layer)
By applying a photoresist material containing carbon black on a substrate by spin coating and baking. A thin film having a thickness of 2 μm containing carbon black was formed.

[Production of Organic EL Element 106]
In the production of the organic EL element 102, the organic EL element 106 was produced in the same manner except that the black light absorption layer used in the organic EL element 105 was formed as the functional layer.

≪Evaluation≫
(1) Measurement of light emission luminance Each of the produced organic EL devices was allowed to emit light continuously at a constant current of ^2.5 mA / cm ² at room temperature, and the light emission luminance was measured using a spectral radiance meter CS-1000 (manufactured by Konica Minolta). ). The measured luminance value was shown as a relative value with the value of the organic EL element 106 as 100.

(2) Color misregistration evaluation (ΔExy)
Using a spectral radiance meter CS-1000 (manufactured by Konica Minolta), the angle dependence of the chromaticity of each organic EL element is measured up to an angle of ± 80 ° in front and every 5 °. The value of ΔE when the deviation ΔE is maximum was obtained from the following formula on the first transparent electrode side (substrate side) and the second transparent electrode side (sealing side), respectively. In the following formula, x and y are chromaticity x and y in the CIE 1931 color system.

ΔE = (Δx ² + Δy ² ) ^1/2
Regarding ΔExy measured above, the larger ΔExy, the greater the change in color tone or the like expressed by the change in viewing angle.

The above evaluation results are shown in Table 1 below.

From Table 1, it is clear that the

organic EL elements

101 and 102 having the white light diffusive reflecting layer as the functional layer containing the white pigment according to the present invention have higher emission luminance and smaller color shift than the comparative example. is there.

Example 2
[Production of Organic EL Element 201]
An organic EL element 201 was produced in the same manner except that the organic EL element 101 of Example 1 was replaced with the following substrate, first transparent electrode, and second transparent electrode.

(Production of substrate)
A 125 μm thick polyethylene naphthalate film (Teonex Dupont Film Co., Ltd., Teonex Extremely Low Heat Yield PEN Q83) is placed in a vacuum tank equipped with a resistance heating boat made of tungsten containing aluminum (Al), and the degree of vacuum Depressurize to 4 × 10 ⁻⁴ Pa, deposit an aluminum (Al) layer with a thickness of 50 μm on the PEN film at a deposition rate of 0.3 to 0.5 nm / second, and produce a light-reflective substrate. did.

(Formation of first transparent electrode)
First, a PEN film formed with a functional layer containing a white pigment is set in a substrate holder, and these substrate holders and a resistance heating boat made of tungsten containing silver (Ag) are placed in the first vacuum chamber of the vacuum evaporation apparatus. Attached. After reducing the pressure in the first vacuum chamber to 4 × 10 ⁻⁴ Pa, the heating boat was energized and heated to form a first transparent electrode having a single layer structure made of silver by resistance heating vapor deposition. The layer thickness of the formed first transparent electrode made of silver (Ag) was 9 nm.

(Formation of second transparent electrode)
Silver (Ag) is used as the second transparent electrode forming material on the formed electron injection layer except for the portion to be the extraction electrode of the first transparent electrode under a vacuum of 5 × 10 ⁻⁴ Pa. Then, a mask pattern was formed so as to have a light emission area of 50 mm square by the resistance heating vapor deposition so as to have the extraction electrode, and a second transparent electrode having a thickness of 9 nm was laminated.

[Production of Organic EL Element 202]
An organic EL element 202 was produced in the same manner as in the production of the organic EL element 102 of Example 1, except that the substrate, the first transparent electrode, and the second transparent electrode used in the organic EL element 201 were used.

[Production of Organic EL Element 203]
In the production of the organic EL element 201, an organic EL element 203 was produced in the same manner except that the first transparent electrode was replaced with the following electrode.

(Formation of first transparent electrode)
First, a PEN film formed up to a functional layer containing a white pigment is set in a substrate holder, the following compound A is put in a resistance heating boat made of tantalum, and these substrate holder and heating boat are connected to the first vacuum tank of the vacuum deposition apparatus. Attached to.

In this state, first, the first vacuum chamber was depressurized to 4 × 10 ⁻⁴ Pa, and then heated by energizing the heating boat containing Compound A, and the layer thickness was 25 nm on the substrate at a deposition rate of 0.1 nm / second. An underlayer which is a transparent functional layer made of Compound A was provided.

Next, the substrate on which the base layer was formed was transferred to the second vacuum chamber in a vacuum, the second vacuum chamber was depressurized to 4 × 10 ⁻⁴ Pa, and then a resistance heating boat made of tungsten containing silver (Ag) The first transparent electrode having a single layer structure made of silver was formed by resistance heating vapor deposition. The layer thickness of the formed first transparent electrode made of silver (Ag) was 9 nm.

[Production of Organic EL Element 204]
In the production of the organic EL element 202, an organic EL element 204 was produced in the same manner except that the first transparent electrode was replaced with the electrode used in the organic EL element 203.

[Production of organic EL elements 205 to 211]
On the PEN film deposited with Al, a specular light reflecting layer and a black light absorbing layer are formed in the same manner as in Example 1, and the organic EL elements having the configuration shown in Table 2 are formed in the same manner as the fabrication of the organic EL elements 201 to 204 205 to 211 were produced.

≪Evaluation≫
Using the produced organic EL elements 201 to 211 and the

organic EL elements

102 and 106 produced in Example 1, evaluation of light emission luminance and color shift was performed in the same manner as in Example 1, and the results are shown in Table 2. It was.

From Table 2, it can be seen that the organic EL elements 201 to 204 having the white light diffusive reflecting layer according to the present invention reproduce Example 1 and are excellent in light emission luminance and color shift.

Moreover, by using the first transparent electrode and the second transparent electrode as a silver (Ag) thin film electrode, an organic EL element having more flexibility was realized.

Example 3
In the production of the

organic EL elements

203 and 204 produced in Example 2, a heating boat containing MoO ₃ was heated on the second transparent electrode and heated, and a layer containing MoO ₃ was formed on the second transparent electrode. , Formed as an electrode protective layer, and were used as organic EL elements 203b and 204b, respectively. At this time, the vacuum chamber was depressurized to 4 × 10 ⁻⁴ Pa, and then deposited at a deposition rate of 0.1 to 0.2 nm / second to a layer thickness of 50 nm.

≪Evaluation≫
Using the produced organic EL elements 203b and 204b and the

organic EL elements

203 and 204 produced in Example 2, the light emission luminance and the color shift were evaluated in the same manner as in Example 2, and the results are shown in Table 3. It was.

From Table 3, it was found that the organic EL elements 203b and 204b on which the electrode protective layer was formed were more excellent in color shift.

The organic electroluminescence device of the present invention has a functional layer containing at least a white pigment, a first transparent electrode, an organic light emitting layer, a second transparent electrode, and a transparent substrate on a flexible substrate on which a metal layer or a metal foil is laminated. By having the sealing base material in this order, the light extraction efficiency is improved and the color shift is reduced, and it is suitably used for an image display device and a lighting device.

100 Organic EL Element 101 First Transparent Electrode 101a Underlayer 101b Electrode Layer 102 Second Transparent Electrode (Counter Electrode)
DESCRIPTION OF SYMBOLS 103 Organic light emitting layer 103a Hole injection layer 103b Hole transport layer 103c Light emission layer 103d Electron transport layer 103e Electron injection layer 104 Electrode protective layer 105 Transparent sealing substrate 106 Functional layer containing white pigment 107 Smooth layer 110 Substrate 110a Resin Base material 110b Metal layer 110c Resin base material 110e Resin base material 110d Metal layer h Emitted light

Claims

Having a functional layer containing at least a white pigment, a first transparent electrode, an organic light emitting layer, a second transparent electrode, and a transparent sealing substrate in this order on a flexible substrate on which a metal layer or a metal foil is laminated An organic electroluminescence device characterized by the above.
The organic electroluminescent device according to claim 1, further comprising a smooth layer between the functional layer containing the white pigment and the first transparent electrode.
3. The organic electroluminescent element according to claim 1, wherein either the first transparent electrode or the second transparent electrode contains silver or an alloy containing silver as a main component.
The base layer containing an organic compound having at least one atom selected from a nitrogen atom and a sulfur atom is provided on the flexible substrate side of the first transparent electrode. The organic electroluminescent element according to any one of 3 to 3.
The organic electroluminescent element according to any one of claims 1 to 4, further comprising an electrode protective layer on the second transparent electrode.
The organic electroluminescent element according to claim 5, wherein the electrode protective layer contains a metal oxide.