JP2016225092A - Laminated organic electroluminescent element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated organic electroluminescent element of which the luminescent color can be arbitrarily controlled and which improves current efficiency (cd/A), reduces angle-of-view dependence of luminescent chromaticity and reduces variations in luminescent properties.SOLUTION: The laminated organic electroluminescent element comprises a transparent substrate, a transparent first electrode, a plurality of luminescent units with different maximal luminescent wavelengths of a maximum peak and a second electrode in this order. A transparent intermediate electrode is included between the plurality of luminescent units, and a light scattering layer is included between the luminescent unit that is neighboring to the transparent intermediate electrode and located at a light extraction side, and the transparent intermediate electrode.SELECTED DRAWING: None

Description

  The present invention relates to a stacked organic electroluminescent element. More specifically, it is an organic electroluminescent element in which the emission color can be arbitrarily controlled, and is a laminated organic compound that has excellent current efficiency (cd / A), small viewing angle dependency of emission chromaticity, and small variation in emission characteristics. The present invention relates to an electroluminescence element.

  At present, a light-emitting element using electroluminescence (EL) of an organic material has attracted attention as a thin light-emitting device.

  A so-called organic electroluminescence element (hereinafter also referred to as an organic EL element) is a thin-film type complete solid-state element that can emit light at a low voltage of about several V to several tens V, and has high luminance, high luminous efficiency, thin thickness, It has many excellent features such as 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.

  Among them, the range of application of the stacked organic EL element that emits light in a planar shape and can freely change the emission color is wide.

  As a laminated organic EL element, Patent Document 1 discloses an organic EL element in which a plurality of light emitting layers, an intermediate electrode layer, and a charge generation layer are laminated between an anode (anode) layer and a cathode (cathode) layer.

  However, when an aluminum film is used as the intermediate electrode, the transparency is inferior due to the transmittance of the intermediate electrode layer, so the light extraction efficiency is low, and when a magnesium-silver film is used, the stability is improved. Inferior, there was a problem in device reliability.

  Furthermore, when laminating the plurality of light emitting layers, if there is a change in the design of the layer thickness of the light emitting layer, or if there is a change in the layer thickness in the actual manufacturing process, the emission center in the layer thickness maintaining direction is changed. There is a problem that the variation in position affects the light extraction efficiency and the viewing angle dependency.

  On the other hand, a technique for improving the light extraction efficiency by inserting a layer having a function of scattering light (referred to as a light scattering layer in the present application) between the transparent electrode on the light extraction side and the transparent substrate is known. (For example, refer to Patent Document 2).

  According to the study by the present inventors, by forming the light scattering layer between the transparent electrode on the light extraction side of the stacked organic EL element and the transparent substrate, the light extraction efficiency and the viewing angle dependency are surely established. Although slightly improved, a practically sufficient effect could not be obtained.

International Publication No. 2013/141057 US Pat. No. 6,965,197

  The present invention has been made in view of the above-described problems and circumstances, and a solution to the problem is an organic electroluminescent element whose emission color can be arbitrarily controlled, which has excellent current efficiency (cd / A), emission chromaticity. It is an object of the present invention to provide a stacked organic electroluminescent element having a small viewing angle dependency and a small variation in light emission characteristics.

  In order to solve the above problems, the present inventor has a transparent intermediate electrode between a plurality of light emitting units having different maximum wavelengths of light emission in the process of examining the cause of the above problem, and the transparent intermediate electrode It has been found that the object of the present invention can be achieved by a stacked organic electroluminescent element having a light scattering layer between the light emitting unit adjacent to the light extraction side and the transparent intermediate electrode.

  That is, the said subject which concerns on this invention is solved by the following means.

1. A laminated organic electroluminescent element having a transparent substrate, a transparent first electrode, a plurality of light emitting units having different maximum light emission maximum wavelengths, and a second electrode in this order,
A laminated type comprising a transparent intermediate electrode between the plurality of light emitting units, and a light scattering layer between the light emitting unit adjacent to the transparent intermediate electrode and on the light extraction side and the transparent intermediate electrode. Organic electroluminescence element.

  2. 2. The stacked organic electroluminescent element according to claim 1, wherein the light scattering layer is a functional layer of the light emitting unit adjacent to the transparent intermediate electrode and located on the light extraction side.

  3. The stacked organic electroluminescent device according to claim 1 or 2, further comprising a second light scattering layer between the transparent substrate and the transparent first electrode.

  An organic electroluminescent element in which the emission color can be arbitrarily controlled by the above-described means of the present invention, which has excellent current efficiency (cd / A), small viewing angle dependency of emission chromaticity, and small variation in emission characteristics. A stacked organic electroluminescent element can be provided.

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

  In a stacked organic electroluminescent element having a plurality of light emitting units and a transparent intermediate electrode, a layer having light scattering properties is provided between the light emitting unit on the light extraction side adjacent to the transparent intermediate electrode and the transparent intermediate electrode. As a result, it is possible to reduce the light loss due to the waveguide mode generated at the interface between the transparent intermediate electrode and the organic layer and the light loss due to the plasmon mode inside the transparent intermediate electrode, resulting in improved light extraction efficiency. Inferred.

  Further, by forming the light scattering layer according to the present invention, it is possible to reduce light loss due to the waveguide mode generated at the interface between the transparent intermediate electrode and the organic layer, so in the manufacturing process of laminating a plurality of light emitting layers, It is presumed that the variation in the light emission characteristics can be reduced even when the thickness of the light emitting layer varies.

  Furthermore, since the microcavity effect at the location can be reduced, light interference is unlikely to occur, and it is presumed that the viewing angle dependency, in which the emission chromaticity changes depending on the viewing angle, can be reduced.

Schematic which shows an example of a structure of the organic EL element which has the two-layer light emission unit of this invention. Schematic which shows an example of a structure of the organic electroluminescent element which has the light emitting unit of 3 layers of this invention. Schematic which shows another example of a structure of the organic EL element which has a two-layer light emission unit of this invention. Schematic which shows another example of a structure of the organic EL element which has the light emitting unit of 3 layers of this invention.

  The laminated organic electroluminescent element of the present invention comprises a transparent substrate, a transparent first electrode, a plurality of light emitting units having different maximum wavelengths of light emission, and a second electrode, wherein a transparent intermediate electrode is provided between the plurality of light emitting units. And having a light scattering layer between the light emitting unit adjacent to the transparent intermediate electrode and on the light extraction side and the transparent intermediate electrode. This feature is a technical feature common to the inventions according to claims 1 to 3.

  As an embodiment of the present invention, from the viewpoint of manifestation of the effect of the present invention, the light scattering layer is a functional layer of the light emitting unit adjacent to the transparent intermediate electrode and located on the light extraction side, so that the device can be thinned. From the viewpoint of production efficiency, this is a preferred embodiment.

  Furthermore, having a second light scattering layer between the transparent substrate and the transparent first electrode can reduce the light loss due to the substrate mode in addition to the light loss due to the waveguide mode, and can extract light. This is a preferred embodiment from the viewpoint of further improving efficiency and viewing angle dependency.

  Hereinafter, the present invention, its components, and modes and modes for carrying out the present invention will be described in detail. In addition, in this application, "-" is used in the meaning which includes the numerical value described before and behind that as a lower limit and an upper limit.

<< Outline of Multilayer Organic Electroluminescence Device of the Present Invention >>
The laminated organic electroluminescence element of the present invention (hereinafter also referred to as the organic EL element of the present invention) includes a transparent substrate, a transparent first electrode, a plurality of light emitting units having different maximum wavelengths of light emission, and a second electrode. In the above, a transparent intermediate electrode is provided between the plurality of light emitting units, and a light scattering layer is provided between the light emitting unit adjacent to the transparent intermediate electrode and on the light extraction side and the transparent intermediate electrode. .

  In the present invention, “a plurality of light emitting units having different maximum light emission wavelengths” is a plurality of light emitting units each having a maximum light emission maximum wavelength in an emission spectrum from a light emitting layer, which will be described later. Are defined as a plurality of light emitting units each having a light emitting layer that emits light of different wavelengths within a range of 10 to 200 nm, more preferably within a range of 10 to 100 nm.

  Specifically, when the organic EL element of the present invention is applied to an organic EL element that produces white light emission, a plurality of light emitting colors can be simultaneously emitted by a plurality of light emitting materials to obtain white light emission by color mixing. The combination of a plurality of emission colors may include emission colors having emission maximum wavelengths of three different maximum peaks of the three primary colors of red, green, and blue, blue and yellow, blue green and orange, etc. It may contain a light emission color having a light emission maximum wavelength of two different maximum peaks using a complementary color relationship.

  The combination of the light emitting materials for obtaining the plurality of emission colors is a combination of a plurality of phosphorescent or fluorescent materials, a light emitting material that emits fluorescence or phosphorescent light, and excitation light from the light emitting material. As a white organic EL element, a combination of a plurality of light-emitting dopants can be realized.

  For example, the blue emission color emission dopant is an emission dopant having an emission maximum in the region of 440 to 490 nm, and the green emission color emission dopant is an emission dopant having an emission maximum in the region of 500 to 540 nm, This can be realized by using a light emitting dopant having a light emission maximum in a region of 600 to 640 nm. The maximum emission wavelength of the maximum peak of the emission spectrum of these luminescent dopants can be obtained from the emission spectrum of the organic EL element, and a spectral radiance meter CS-1000 (manufactured by Konica Minolta) can be used for measurement.

  The term “transparent” as used in the present invention means that the substrate, the electrode, and the light emitting layer are each made of a light transmittance at a light wavelength of 550 nm using a spectrophotometer (for example, U-3300 manufactured by Hitachi High-Technologies Corporation). It means having a light transmittance of 15% or more when (%) is measured. The light transmittance of each element constituting the organic EL element is preferably 40% or more, more preferably 60% or more, and particularly preferably 80% or more.

<Configuration of Laminated Organic Electroluminescence Element of the Present Invention>
In the present application, a light scattering layer between the light emitting unit adjacent to the transparent intermediate electrode and on the light extraction side and the transparent intermediate electrode is referred to as “light scattering layer 1”, between the transparent substrate and the transparent first electrode. A certain light scattering layer is described as “light scattering layer 2”.

  The configuration of the organic EL device of the present invention will be described with reference to the drawings. However, the present invention is not limited thereby.

  FIG. 1 is a schematic diagram showing an example of the configuration of an organic EL element having a two-layer light emitting unit of the present invention.

  In the case of the organic EL element 100 having two light emitting units, as shown in FIG. 1, transparent substrate 108 / transparent first electrode 101 / first light emitting unit 103-1, light scattering layer 105 / smooth layer 106 / transparent. Basically, the intermediate electrode 104-1 / second light emitting unit 103-2 / second electrode 102 / adhesive 107 (not shown) / sealing member 109 are laminated in this order. The smooth layer 106 may be omitted.

  As an example, the first light emitting unit 103-1 has a hole injection layer 103-1 a, a hole transport layer 103-1 b, a light emitting layer 103-1 c, an electron transport layer 103-1 d, and an electron injection layer 103-1 e stacked in this order. (The second light-emitting unit has the same configuration but is not shown).

  In another embodiment of the organic EL device of the present invention, it is also preferable that the electron transport layer 103-4 of the first light emitting unit contains light scattering fine particles to form an electron transport / light scattering layer.

  Each of the transparent first electrode 101 and the transparent intermediate electrode 104-1 is wired with a lead wire, and by applying about 2 to 40V as a driving voltage V1 to each connection terminal, the first light emitting unit 103-1 is connected. Emits light. Similarly, the transparent intermediate electrode 104-1 and the second electrode are also wired with lead wires, and the second light emitting unit 103-2 emits light by applying about 2 to 40 V as the driving voltage V <b> 2 to each connection terminal. .

Specifically, when the organic EL element 100 is driven, when the DC voltage is applied to the V ₁ and V ₂ , the transparent first electrode 101 that is an anode (anode) has a positive polarity and a cathode (cathode). The second electrode 102 having a negative polarity is applied within a voltage range of 2 to 40 V, and an intermediate voltage between the anode (anode) and the cathode (cathode) is applied to the transparent intermediate electrode.

  As the first light emitting unit 103-1 and the second light emitting unit 103-2, it is preferable to use two types of light emitting units selected from blue, green and red, or a light emitting unit having a light emission color in which they are mixed.

  For example, the light emission color can be changed by arranging light emitting units having different emission maximum wavelengths at the maximum peak, such as a blue light emitting layer / red light emitting layer configuration and a green light emitting layer / red light emitting layer configuration. This is preferable from the viewpoint of easy adjustment.

  In addition, for example, white light can be easily obtained by selecting two types of emitted light so as to have a complementary color relationship such as blue light emitting layer / yellow light emitting layer.

  That is, when light emission units exhibiting different emission colors are stacked to obtain white light emission, it is preferable that these light emission units have a complementary color relationship with each other. For example, an organic EL element that emits white light can be obtained by providing a blue light-emitting layer and a light-emitting unit that emits a complementary green-yellow, yellow, or orange (orange) light-emitting color. The “complementary color” relationship is a relationship between colors that become achromatic when mixed. That is, white light emission can be obtained by mixing light emission of substances emitting light of complementary colors.

  FIG. 2 is a schematic diagram illustrating an example of a configuration of an organic EL element having a three-layer light emitting unit of the present invention.

  In the case of the organic EL element 100 having a three-layer light emitting unit, as shown in FIG. 2, transparent substrate 108 / transparent first electrode 101 / first light emitting unit 103-1 / light scattering layer 105-1 / smooth layer 106 -1 / transparent intermediate electrode 104-1 / second light emitting unit 103-2 / light scattering layer 105-2 / smooth layer 106-2 / transparent intermediate electrode 104-2 / third light emitting unit 103-3 / second electrode 102 It is basically laminated in the order of / adhesive 107 (not shown) / sealing member 109. The transparent intermediate electrode and the light scattering layer may be the same or different, and the smooth layers 106-1 and 106-2 can be omitted.

  In the first light emitting unit 103-1, for example, a hole injecting layer 103-1a, a hole transporting layer 103-1b, a light emitting layer 103-1c, an electron transporting layer 103-1d, and an electron injecting layer 103-1e are sequentially stacked. Similarly, in the second light emitting unit, the hole injection layer 103-2a, the hole transport layer 103-2b, the light emission layer 103-2c, the electron transport layer 103-2d, and the electron injection layer 103-2e are sequentially stacked. (The third light emitting unit has the same configuration but is not shown).

  In another embodiment of the organic EL device of the present invention, the electron transport layer 103-1d of the first light emitting unit may contain light scattering fine particles to form an electron transport / light scattering layer, or the electrons of the second light emitting unit. The transport layer 103-2d may contain light scattering fine particles to form an electron transport / light scattering layer.

  The first light-emitting unit 103-1, the second light-emitting unit 103-2, and the third light-emitting unit 103-3 are preferably light-emitting units that have blue, green, red, or a mixed emission color.

  For example, the first light-emitting unit 103-1, the second light-emitting unit 103-2, and the third light-emitting unit 103-3 each have a blue light-emitting layer / green light-emitting layer / red light-emitting layer configuration. Can be emitted, which is preferable.

  The position of the light emission center of each light emitting unit varies depending on the type of organic layer to be stacked, the layer thickness, manufacturing variations, etc., but the microcavity effect is reduced by forming the light scattering layer according to the present invention. Even if the position of the emission center varies, it is possible to reduce the viewing angle dependence of the emitted light from each. Here, the “emission center” refers to a position where the emission energy has a peak when the emission energy in the thickness direction of the light emitting unit is measured. Specifically, it can be specified by the method described in JP2009-181829A.

FIG. 3 is a schematic view showing another example of the configuration of the organic EL element having the two-layer light emitting unit of the present invention, and the second light scattering layer 110 is provided between the transparent substrate 108 and the transparent first electrode 101. Formed. It is preferable to provide a smoothing layer 111 described later between the second light scattering layer 110 and the transparent first electrode 101. By having the second light scattering layer, in addition to the light loss due to the waveguide mode, the light loss due to the substrate mode can be reduced, and the light extraction efficiency and the viewing angle dependency can be further improved. FIG. 5 is a schematic view showing another example of the configuration of the organic EL element having the three-layer light emitting unit, in which a second light scattering layer 110 is formed between the transparent substrate 108 and the transparent first electrode 101. Providing a smoothing layer 111 described later between the second light scattering layer 110 and the transparent first electrode 101 reduces the influence of surface irregularities of the light scattering layer 110 when forming the transparent first electrode. To preferred.

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

[1] Light scattering layer 1
The light scattering layer 1 disposed between the light emitting unit adjacent to the transparent intermediate electrode and on the light extraction side and the transparent intermediate electrode according to the present invention contains nanoparticles having a high refractive index as light scattering particles. It is preferable. Examples thereof include inorganic oxides or product particles made of at least one oxide selected from zirconium, titanium, aluminum, indium, zinc, tin, antimony, and the like. Specific examples of the inorganic oxide particles include ZrO ₂ , TiO ₂ , BaTiO ₃ , Al ₂ O ₃ , In ₂ O ₃ , ZnO, SnO ₂ , Sb ₂ O ₃ , ITO, zeolite, and the like. , TiO ₂ , BaTiO ₃ , ZrO ₂ , ZnO, SnO ₂ are preferable, and TiO ₂ and SnO ₂ are more preferable. Among TiO _2, the rutile type is preferable to the anatase type because the weather resistance of the smooth layer and the adjacent layer described later is high because the catalytic activity is low, and the refractive index is high.

  It is preferable that the nanoparticles have a refractive index in the range of 1.7 to 3.0 and are included in a binder as a medium to form a film. If the refractive index of the nanoparticles is 1.7 or more, the intended effect can be sufficiently exerted. If the refractive index of a nanoparticle is 3.0 or less, the multiple scattering in a layer will be suppressed and transparency will not be reduced.

  Nanoparticles are defined as fine particles (colloidal particles) having a particle size dispersed in a dispersion medium of the order of nanometers. The particles include discrete particles (primary particles) and agglomerated particles (secondary particles), which are defined as nanoparticles including secondary particles.

  The lower limit of the particle diameter of the nanoparticles 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 of a nanoparticle, 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. It is preferable at the point from which high transparency is acquired because the particle diameter of a nanoparticle exists in the range of 5-60 nm. As long as the effect is not impaired, the particle size distribution is not limited and may be wide or narrow and may have a plurality of distributions. Here, the particle diameter refers to the volume average value of the diameter (sphere converted particle diameter) when each particle is converted into a sphere having the same volume.

  The in-plane occupation ratio of the light scattering particles contained in the light scattering layer 1 in the light scattering layer 1 is preferably 30% or more, more preferably 50% or more, and particularly preferably 70% or more.

  The “in-plane occupation ratio of the light scattering particles in the light scattering layer” refers to the area occupation ratio of the light scattering particles in the plane when the light scattering layer is viewed in plan.

  If the in-plane occupancy is 30% or more, the space between the light scattering particles is moderate and a scattering effect is exhibited, and if the in-plane occupancy is 70% or more, light scattering in the light scattering layer is optimal. It will be a thing.

  It is preferable to form the light scattering layer 1 by dispersing and dissolving the nanoparticles in an appropriate solvent to prepare a coating solution and then coating the nanoparticles. The coating can be suitably performed by a method such as spin coating, slit die coating, blade coating, spraying, ink jet, letterpress printing, offset printing, and gravure printing.

  Further, the light scattering layer 1 according to the present invention includes, as light scattering particles, anisotropic metal oxide fine particles having a major axis and a minor axis, anisotropic metal salt fine particles, or atoms other than carbon atoms and metals. It is also preferred to add anisotropic organic compound fine particles.

  The anisotropic fine particles preferably have a minor axis diameter of 5 to 50 nm and an aspect ratio of 3 to 500. Here, the aspect ratio refers to the ratio of the major axis diameter to the minor axis diameter of the anisotropic particles, and the median diameter of each of the major axis diameter and the minor axis diameter measured by observing 100 anisotropic particles with an optical microscope. Can be obtained from The median diameter refers to the particle diameter corresponding to the median value of the distribution.

  The total light transmittance of the layer containing anisotropic metal oxide fine particles, anisotropic metal salt fine particles, or anisotropic organic compound fine particles composed of carbon atoms and other atoms other than metal is anisotropic metal oxide. 80% or more of the total light transmittance before addition of fine particles, anisotropic metal salt fine particles, or anisotropic organic compound fine particles composed of atoms other than carbon atoms and metals, or anisotropic metal oxides The degree of cloudiness of the layer containing at least one of fine particles, anisotropic metal salt fine particles, or anisotropic organic compound fine particles composed of carbon atoms and other atoms other than metal is before the addition of anisotropic fine particles. It is preferable that the degree of cloudiness is 2 to 40 times, and the degree of cloudiness before addition of anisotropic fine particles is 0.01 to 10%. Furthermore, added anisotropic metal oxide fine particles, anisotropic metal salt fine particles, or anisotropic organic compound fine particles composed of carbon atoms and other atoms other than metals, the major axis of the fine particles is parallel to the substrate surface. It is more preferable that there are relatively many things.

  Anisotropic metal oxide fine particles, anisotropic metal salt fine particles, or anisotropic organic compound fine particles composed of atoms other than carbon atoms and metals (hereinafter also simply referred to as anisotropic fine particles) used in the present invention are: It is characterized by having anisotropy having a major axis and a minor axis, and as described above, the minor axis length is preferably 5 to 50 nm and the aspect ratio is preferably 3 to 500. The short axis is more preferably 10 to 30 nm, and the aspect ratio is more preferably 10 to 200. The short axis length and the aspect ratio can be arbitrarily selected, and a plurality of short axis lengths and aspect ratios may be mixed. Specifically, it is possible to select an optimal one that has a minor axis length and an aspect ratio that are almost uniform according to the wavelength of the light emitted from the light emitting layer and consequently irradiated to the outside of the device. In the case of white light emission, for example, anisotropic fine particles having a wide particle size distribution can be selected, and a plurality of types having a uniform short axis length and aspect ratio may be mixed.

  Specifically, as the anisotropic fine particles used in the present invention, metal oxide fine particles, metal salt fine particles, anisotropic organic compound fine particles composed of atoms other than carbon atoms and metals are preferably used. It is preferable to select and use one that does not cause absorption, light emission, fluorescence, or the like in the wavelength region used as an optical element.

As anisotropic metal oxide fine particles, the metal constituting the metal oxide is Li, Na, Mg, Al, Si, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu. , Zn, Rb, Sr, Y, Nb, Zr, Mo, Cd, In, Sn, Sb, Cs, Ba, La, Ta, Hf, W, Ir, Tl, Pb, Bi and a rare earth metal In particular, for example, titanium oxide, zinc oxide, aluminum oxide (alumina), zirconium oxide, hafnium oxide, niobium oxide, tantalum oxide, oxidation, and the like can be used. Magnesium, barium oxide, indium oxide, tin oxide, lead oxide, and double oxides composed of these oxides, lithium niobate, potassium niobate, lithium tantalate, aluminum Neshiumu oxides in (MgAl 2 _{O 4)} or the like of the particles and the composite particles may be selected minor axis, one having a long axis.

  In addition, rare earth oxides can also be used as anisotropic metal oxide fine particles. Specifically, scandium oxide, yttrium oxide, lanthanum oxide, cerium oxide, praseodymium oxide, neodymium oxide, samarium oxide, europium oxide, oxide Examples also include gadolinium, terbium oxide, dysprosium oxide, holmium oxide, erbium oxide, thulium oxide, ytterbium oxide, and lutetium oxide.

  As anisotropic metal salt fine particles, those having a short axis and a long axis among carbonates, phosphates, sulfates and composite particles thereof can be applied. Specific examples include strontium carbonate, calcium carbonate, magnesium sulfate, and potassium titanate. In addition, oxo clusters of Ti and Zr are applicable.

  As a method for preparing anisotropic metal oxide fine particles and anisotropic metal salt fine particles (hereinafter also referred to as inorganic fine particles), it is possible to obtain fine particles by spraying and firing raw materials of inorganic particles in the gas phase. It is. Furthermore, a method of preparing particles using plasma, a method of ablating raw material solids with a laser or the like to form fine particles, a method of oxidizing evaporated metal gas to prepare inorganic fine particles, and the like can be suitably used. Further, as a method for preparing in the liquid phase, it is possible to prepare an inorganic fine particle dispersion liquid which is dispersed almost as primary particles by using a sol-gel method using alkoxide or chloride solution as a raw material. Alternatively, it is possible to obtain a dispersion having a uniform particle size by using a reaction crystallization method utilizing a decrease in solubility.

  The particles obtained in the liquid phase are preferably dried and fired to stably bring out the function of the inorganic particles. For drying, means such as freeze drying, spray drying, supercritical drying and the like can be applied, and the firing is performed not only by increasing the temperature while controlling the atmosphere but also by using an organic or inorganic sintering inhibitor. It is preferable.

  Examples of anisotropic organic compound fine particles composed of atoms other than carbon atoms and metals include particles such as polyimide resin, acrylic resin, styrene resin, polyethylene terephthalate resin, silicone resin, and fluoride resin.

Among the above anisotropic fine particles, it is cheap and it is possible to select inorganic fine particles in consideration of safety, and considering the ease of reducing the particle size, the following inorganic particles can be used. preferable. _{That, TiO 2, Al 2 O 3} , SiO 2, LiNbO 3, Nb 2 O 5, ZrO 2, Y 2 O 3, MgO, ZnO, SnO 2, Bi 2 O 3, ITO, CeO 2, Sr 2 CO 3 It is particularly preferable to use KTaO ₃ or the like.

  Although there is no restriction | limiting in particular about the addition amount to the light-scattering layer of an anisotropic fine particle, The total light transmittance (single layer film) of the layer containing an anisotropic fine particle is less than 80% of the total light transmittance before addition. It is preferable to add so that it does not become. Moreover, it is preferable that the degree of cloudiness (single layer film) before addition of anisotropic fine particles is 0.1 to 10%, and the degree of cloudiness after addition of anisotropic fine particles is 2 to 40 times before addition. In addition, the value of the total light transmittance and cloudiness in this invention can be measured with a Nippon Denshoku Industries Co., Ltd. NDH-5000 type | mold haze meter. For example, it can be measured by a single film coated with a film thickness of 300 nm on a polyethylene terephthalate resin having a thickness of 120 μm.

  In the case of filling anisotropic fine particles of 50 nm or less, it is preferably 20% by volume or less in order to ensure light transmittance in a state where a certain degree of cloudiness is ensured. On the other hand, in order to change the optical physical properties (change in the light traveling direction) by adding anisotropic fine particles, it is preferably 2% by volume or more, and more preferably 6% by volume or more. The volume fraction of the anisotropic fine particles here is expressed by the formula (x / a) where the specific gravity of the anisotropic fine particles is a, the content is x grams, and the total volume of the composite material produced is Y milliliters. ) / Y × 100.

  The fine particle content can be determined by observing a semiconductor crystal image with a transmission electron microscope (TEM) (information on the semiconductor crystal composition can also be obtained by local elemental analysis such as EDX), or by a given resin composition It can be calculated from the contained mass of a predetermined composition obtained by elemental analysis of the ash content and the specific gravity of crystals of the composition.

  The major axis of the anisotropic fine particles is preferably substantially parallel to the substrate surface or the interface between the layers. “Substantially parallel” means that 70% or more of the number of anisotropic fine particles has an angle between the major axis and the substrate surface or each layer interface of 30 ° or less. If the major axis and the substrate surface or the interface of each layer are substantially parallel, when the interface of the substrate or each layer is the xy plane, the major axis and minor axis directions may be in the x direction or the y direction. Good.

  If the anisotropic fine particle composition is uniform, anisotropic fine particles having a short axis and a long axis are represented by spin coating method, slit die coating method, blade coating method when applying a liquid to which this is added, A method of applying a force in the direction parallel to the substrate surface and extending the coating solution is preferable.

  The light scattering layer 1 is disposed between the light emitting unit adjacent to the transparent intermediate electrode according to the present invention and on the light extraction side and the transparent intermediate electrode, and is preferably formed as an upper layer of the light emitting unit. In that case, it is a preferable aspect to provide a smoothing layer described later between the light scattering layer 1 and the transparent intermediate electrode.

  The light scattering layer 1 according to the present invention is preferably a functional layer of the light emitting unit adjacent to the transparent intermediate electrode and located on the light extraction side, and the functional layer is an electron transport layer described later, and an electron transport / It is preferable to form a light scattering layer.

[2] Light scattering layer 2
The organic EL device of the present invention preferably further includes a light scattering layer 2 that is a second light scattering layer between the transparent substrate and the transparent first electrode.

  The refractive index of the light scattering layer 2 at a light wavelength of 550 nm is preferably in the range of 1.7 or more and less than 3.0.

  Waveguide mode light confined in the light emitting layer of the organic EL element and plasmon mode light reflected from the cathode are light of specific optical modes, and in order to extract these lights, a refractive index of at least 1.7 or more is required. is necessary.

Actually, it is preferable to combine a smooth layer with the light scattering layer 2, but it is preferable that each refractive index is in a range of 1.7 or more and less than 2.5. Since it is often difficult to measure, it is sufficient that the refractive index satisfies the above range as the entire second light scattering layer.
The refractive index is measured by irradiating a light beam having the shortest light emission maximum wavelength among the light emission maximum wavelengths of light emitted from the light emitting unit in an atmosphere at 25 ° C., and Abbe refractometer (manufactured by ATAGA, DR-M2). To do.

  The haze value of the light scattering layer 2 (the ratio of the scattering transmittance to the total light transmittance) is 30% or more. If the haze value is 30% or more, the luminous efficiency can be improved.

  The haze value is a physical property value calculated under the influence of (i) the refractive index difference of the composition in the layer and (ii) the influence of the surface shape. In the present invention, the haze value as a second light scattering layer in which a smooth layer is laminated on the light scattering layer 2 is measured. That is, by measuring the haze value while keeping the surface roughness below a certain level, the haze value excluding the influence of (ii) is measured.

  Further, the light scattering layer 2 according to the present invention preferably has a transmittance of 50% or more, more preferably 55% or more, and particularly preferably 60% or more.

  Although it is preferable that the light scattering layer 2 has a high transmittance, it is assumed that the light scattering layer 2 actually has a numerical value of less than 80%.

  As described above, the light scattering layer 2 is preferably a high refractive index layer having a refractive index in the range of 1.7 or more and less than 3.0. In this case, the light scattering layer 2 may be formed of a single material having a refractive index of 1.7 or more and less than 3.0, or mixed with two or more compounds to have a refractive index of 1.7 or more and 3 Less than 0.0 layers may be formed. In the case of such a mixed system, the refractive index of the light-scattering layer 2a can be substituted by a calculated refractive index calculated by a total value obtained by multiplying the refractive index specific to each material by the mixing ratio. In this case, the refractive index of each material may be less than 1.7 or 3.0 or more, and it is sufficient that the mixed layer has a refractive index of 1.7 or more and less than 3.0.

  The light scattering layer 2 is a mixed light scattering layer (scattering film) that utilizes a refractive index difference due to a mixture of a binder and light scattering particles.

  The difference in refractive index between the resin material (monomer or polymer) as a binder and the contained light scattering particles is 0.03 or more, preferably 0.1 or more, more preferably 0.2 or more, Especially preferably, it is 0.3 or more. When the difference in refractive index between the binder and the light scattering particles is 0.03 or more, a scattering effect occurs at the interface between the binder and the light scattering particles. A larger refractive index difference is preferable because refraction at the interface increases and the scattering effect improves.

  Since the light-scattering layer 2 is a layer that scatters light due to the difference in refractive index between the binder and the light-scattering particles, the contained light-scattering particles have a particle size larger than the region that causes Mie scattering in the visible light region. Transparent particles having a mean particle size of 0.2 μm or more are preferable.

  On the other hand, as the upper limit of the average particle diameter, when the particle diameter is larger, it is necessary to increase the thickness of the smooth layer for flattening the roughness of the light scattering layer 2 containing light scattering particles, Since there is a disadvantage in terms of absorption of the layer, it is less than 1 μm.

Here, the average particle diameter of the light scattering particles can be measured by image processing of a transmission electron micrograph (TEM cross section).
The light scattering particle is not particularly limited and may be appropriately selected depending on the purpose. The light scattering particle may be an organic fine particle or an inorganic fine particle, and among them, an inorganic fine particle having a high refractive index may be used. preferable.

  Examples of organic fine particles having a high refractive index include polymethyl methacrylate beads, acrylic-styrene copolymer beads, melamine beads, polycarbonate beads, styrene beads, crosslinked polystyrene beads, polyvinyl chloride beads, and benzoguanamine-melamine formaldehyde beads. Can be mentioned.

Examples of the inorganic fine particles having a high refractive index include inorganic oxide particles made of at least one oxide selected from zirconium, titanium, indium, zinc, antimony, cerium, niobium, tungsten, and the like. Specific examples of the inorganic oxide particles include ZrO ₂ , TiO ₂ , BaTiO ₃ , In ₂ O ₃ , ZnO, Sb ₂ O ₃ , ITO, CeO ₂ , Nb ₂ O ₅ and WO ₃ . Of these, TiO ₂ , BaTiO ₃ , ZrO ₂ , CeO ₂ and Nb ₂ O ₅ are preferable, and TiO ₂ is most preferable. Of TiO _2, the rutile type is more preferable than the anatase type because the catalyst activity is low, so that the weather resistance of the high refractive index layer and the adjacent layer is high and the refractive index is high.

  In addition, these particles are used in the form of a surface treatment from the viewpoint of improving dispersibility and stability when used as a dispersion liquid in order to be contained in the light scattering layer 2 having a high refractive index. It is possible to select whether to use one that does not.

  When performing the surface treatment, specific materials for the surface treatment include different inorganic oxides such as silicon oxide and zirconium oxide, metal hydroxides such as aluminum hydroxide, organic acids such as organosiloxane and stearic acid, and the like. It is done. These surface treatment materials may be used individually by 1 type, and may be used in combination of multiple types. Among these, from the viewpoint of the stability of the dispersion, the surface treatment material is preferably a different inorganic oxide and / or metal hydroxide, more preferably a metal hydroxide.

  When the inorganic oxide particles are surface-coated with a surface treatment material, the coating amount (in general, this coating amount is indicated by the mass ratio of the surface treatment material used on the surface of the particle to the mass of the particles). Is preferably 0.01 to 99% by mass. When the coating amount of the surface treatment material is 0.01% by mass or more, the effect of improving the dispersibility and stability by the surface treatment can be sufficiently obtained, and when it is within 99% by mass, the light having a high refractive index is obtained. It can suppress that the refractive index of the scattering layer 2 falls.

  In addition, as the high refractive index material, quantum dots described in International Publication No. 2009/014707, US Pat. No. 6,608,439, and the like can be suitably used.

  The high refractive index particles have a refractive index of 1.7 or more, preferably 1.85 or more, and particularly preferably 2.0 or more. When the refractive index is 1.7 or more, the difference in refractive index from the binder increases, so that the amount of scattering increases and the effect of improving the light extraction efficiency can be obtained.

  On the other hand, the upper limit of the refractive index of the high refractive index particles is preferably less than 3.0. If the difference in refractive index from the binder is large, a sufficient amount of scattering can be obtained, and the effect of improving the light extraction efficiency can be obtained.

  The high-refractive-index particles are preferably arranged with a thickness of an average particle size so that the light-scattering particles are in contact with or close to the interface between the light-scattering layer 2 and the smooth layer. Thereby, the evanescent light that oozes out to the light scattering layer 2 when total reflection occurs in the smooth layer can be scattered by the particles, and the light extraction efficiency is improved.

  The content of the high refractive index particles in the light scattering layer 2 is preferably in the range of 1.0 to 70%, more preferably in the range of 5 to 50% in terms of volume filling factor. Thereby, the density of the refractive index distribution can be made dense at the interface between the light scattering layer 2 and the smooth layer, and the light extraction efficiency can be improved by increasing the amount of light scattering.

  The light scattering layer 2 is preferably a scattering film made of a mixture using a difference in refractive index between a binder having a low refractive index and light scattering particles having a high refractive index contained in the binder. The binder having a low refractive index has a refractive index nb of less than 1.9, particularly preferably less than 1.6.

  As the binder, the binder used in the light scattering layer 1 can be used, but polysiloxane having Si—O—Si bond (including polysilsesquioxane), polysilazane having Si—N—Si bond, Polysiloxazan containing both Si—O—Si bonds and Si—N—Si bonds can be used.

[3] Smooth layer When a transparent intermediate electrode or a light emitting unit is provided on the light scattering layer 2, the smooth layer is storable in a high temperature and high humidity atmosphere due to irregularities on the surface of the light scattering layer. It is preferably provided in order to prevent adverse effects such as deterioration and electrical short circuit (short circuit).

  It is important that the smooth layer has a flatness that allows an electrode formed thereon to be satisfactorily formed, and the surface property is preferably such that the arithmetic average roughness Ra is in the range of 0.5 to 50 nm. More preferably, it is 30 nm or less, particularly preferably 10 nm or less, and most preferably 5 nm or less. By setting the arithmetic average roughness Ra within the range of 0.5 to 50 nm, it is possible to suppress defects such as a short circuit of the organic EL element to be stacked. 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.

  The smooth layer is preferably a high-refractive index layer having an average refractive index of 1.5 or more, particularly greater than 1.65 and less than 2.5. As long as the average refractive index nf is greater than 1.65 and less than 2.5, it may be formed of a single material or a mixture. In the case of such a mixed system, the average refractive index of the smooth layer uses a calculated refractive index that is calculated by a total value obtained by multiplying the refractive index unique to each material by the mixing ratio.

  As the binder used for the smooth layer, known resins 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, Polyetherimide, silsesquioxane having an organic-inorganic hybrid structure, polysiloxane, polysilazane, polysiloxazan, perfluoroalkyl group-containing silane compound (for example, (heptadecafluoro Other 1,1,2,2-tetradecyl) triethoxysilane), fluorinated copolymer of a monomer constitutional units for imparting a crosslinking group and a fluorine-containing monomer. These resins can be used in combination of two or more. Among these, those having a (meth) acrylic acid ester system and an organic-inorganic hybrid structure are preferable.

  The following hydrophilic resins can also 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. 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.

  As the polymer used as the binder resin, one type may be used alone, or two or more types may be mixed and used as necessary.

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

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

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

  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.

  The smooth layer preferably contains fine particles having a high refractive index in the binder, and preferably high refractive index nanoparticles.

Examples of the high refractive index nanoparticles include inorganic oxide particles made of at least one oxide selected from zirconium, titanium, aluminum, indium, zinc, tin, antimony, and the like. Specific examples of the inorganic oxide particles include ZrO ₂ , TiO ₂ , BaTiO ₃ , Al ₂ O ₃ , In ₂ O ₃ , ZnO, SnO ₂ , Sb ₂ O ₃ , ITO, SiO ₂ , ZrSiO ₄ , zeolite. Among them, TiO ₂ , BaTiO ₃ , ZrO ₂ , ZnO and SnO ₂ are preferable, and TiO ₂ is most preferable. Of TiO _2, the rutile type is more preferable than the anatase type because the catalyst activity is low, the weather resistance of the smooth layer and the adjacent layer is high, and the refractive index is high.

  It is preferable that the nanoparticles have a refractive index in the range of 1.7 to 3.0 and are included in a binder as a medium to form a film. If the refractive index of the nanoparticles is 1.7 or more, the intended effect can be sufficiently exerted. If the refractive index of a nanoparticle is 3.0 or less, the multiple scattering in a layer will be suppressed and transparency will not be reduced.

  The lower limit of the particle diameter of the nanoparticles 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 of a nanoparticle, 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. It is preferable at the point from which high transparency is acquired because the particle diameter of a nanoparticle exists in the range of 5-60 nm. As long as the effect is not impaired, the particle size distribution is not limited and may be wide or narrow and may have a plurality of distributions.

  The thickness of the smooth layer needs to be thick to some extent in order to reduce the surface roughness of the light scattering layer 2, but needs to be thin enough not to cause energy loss due to absorption.

As a method for forming the smooth layer, for example, after the light scattering layer 2 is formed, the dispersion liquid in which the nano TiO ₂ particles are dispersed and the resin solution are mixed and filtered through a filter to obtain a smooth layer preparation solution. The smooth layer can be formed by applying the smooth layer preparation solution on the light scattering layer, drying it, and then irradiating it with ultraviolet rays.

[4] Transparent Substrate As used herein, the term “transparent substrate” refers to a measurement of light transmittance (%) at a light wavelength of 550 nm using a spectrophotometer (U-3300 manufactured by Hitachi High-Technologies Corporation). And having a light transmittance of 50% or more. Preferably it is 60% or more, more preferably 70% or more, and particularly preferably 80% or more.

  The transparent substrate according to the present invention is preferably a flexible substrate.

  The flexible substrate as used in the present invention refers to a substrate that is wound around a φ (diameter) 50 mm roll and does not crack before and after winding with a constant tension, and more preferably a substrate that can be wound around a φ30 mm roll.

  Examples of the flexible substrate according to the present invention include a resin substrate, a thin film metal foil, and a thin plate flexible glass.

  Examples of the resin substrate applicable to the present invention include polyesters such as polyethylene terephthalate (abbreviation: PET), polyethylene naphthalate (abbreviation: PEN), polyethylene, polypropylene, cellophane, cellulose diacetate, and cellulose triacetate (abbreviation: TAC). Cellulose acetate butyrate, cellulose acetate propionate (abbreviation: CAP), cellulose esters such as cellulose acetate phthalate, cellulose nitrate and their derivatives, polyvinylidene chloride, polyvinyl alcohol, polyethylene vinyl alcohol, syndiotactic polystyrene, Polycarbonate (abbreviation: PC), norbornene resin, polymethylpentene, polyetherketone, polyimide, polyethersulfone ( Name: PES), polyphenylene sulfide, polysulfones, polyether imide, polyether ketone imide, polyamide, fluororesin, nylon, polymethyl methacrylate, acrylic and polyarylates, Arton (trade name, manufactured by JSR) and Appel (product) Name, manufactured by Mitsui Chemicals, Inc.) and the like.

  Among these resin substrates, films such as polyethylene terephthalate (abbreviation: PET), polybutylene terephthalate, polyethylene naphthalate (abbreviation: PEN), polycarbonate (abbreviation: PC) are flexible resin substrates in terms of cost and availability. Are preferably used.

  The resin substrate may be an unstretched film or a stretched film.

  The resin substrate applicable to the present invention can be manufactured by a conventionally known general film forming method. For example, an unstretched resin substrate that is substantially amorphous and not oriented can be produced by melting a resin as a material with an extruder, extruding it with an annular die or a T-die, and quenching. In addition, the resin substrate transport direction (vertical axis direction, MD) is applied to the unstretched resin substrate by a known method such as uniaxial stretching, tenter sequential biaxial stretching, tenter simultaneous biaxial stretching, tubular simultaneous biaxial stretching, or the like. Direction) or a direction (horizontal axis direction, TD direction) perpendicular to the transport direction of the resin substrate, the stretched resin substrate can be produced. Although the draw ratio in this case can be suitably selected according to the resin used as the raw material of the resin substrate, it is preferably in the range of 2 to 10 times in the vertical axis direction and the horizontal axis direction.

  The thickness of the resin substrate is preferably a thin resin substrate within the range of 3 to 200 μm, more preferably within the range of 10 to 150 μm, and particularly preferably within the range of 20 to 120 μm. is there.

  Moreover, the thin plate flexible glass applicable as the flexible substrate according to the present invention is a glass plate that is thin enough to be bent. The thickness of the thin flexible glass can be appropriately set within the range in which the thin flexible glass exhibits flexibility.

  Examples of the thin flexible glass include soda-lime glass, barium / strontium-containing glass, lead glass, aluminosilicate glass, borosilicate glass, barium borosilicate glass, and quartz. As thickness of thin plate flexible glass, it is the range of 5-300 micrometers, for example, Preferably it is the range of 20-150 micrometers.

In the organic EL element of the present invention, a gas barrier layer may be provided on the transparent substrate described above as necessary. 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 layer (also referred to as a gas barrier film or the like) is preferable, 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 and a water vapor permeability of 1 × 10 ⁻⁵ g / (m ² · 24 hours) or less is more preferable.

  As a material for forming the gas barrier layer, any material that has a function of suppressing intrusion of water or oxygen that causes deterioration of the organic EL element may be used. For example, an inorganic substance such as silicon oxide, silicon dioxide, or silicon nitride may be used. Can be used. Furthermore, in order to improve the brittleness of the gas barrier layer, it is more preferable to have a laminated structure of these inorganic layers and organic layers made of organic materials. Although there is no restriction | limiting in particular about the lamination | stacking order of an inorganic layer and an organic layer, It is preferable to laminate | stack both alternately several times.

  The method for forming the gas barrier layer is not particularly limited. For example, the vacuum deposition method, sputtering method, reactive sputtering method, molecular beam epitaxy method, cluster ion beam method, ion plating method, plasma polymerization method, atmospheric pressure plasma weight A combination method, a plasma CVD method, a laser CVD method, a thermal CVD method, a coating method, or the like can be used, but an atmospheric pressure plasma polymerization method described in JP-A-2004-68143 is preferable.

[5] Transparent first electrode The transparent first electrode is an electrode that acts as an anode or a cathode. In the case of the anode, the transparent first electrode is an electrode film that supplies (injects) holes into the light emitting layer and has a large work function (4 eV or more). ), For example, electrode materials such as metals, alloys, conductive compounds, and mixtures thereof.

Specifically, in the organic EL device of the present invention, when light is extracted from the transparent first electrode side, the first electrode may be a thin film metal such as gold, silver, or aluminum, or ITO (indium tin oxide). ), Tin oxide (SnO ₂ ), zinc oxide (ZnO), gallium zinc oxide (GZO), indium gallium zinc oxide (IGZO), and the like.

  In the organic EL device of the present invention, when light is extracted from the first electrode side, the light transmittance of the first electrode is preferably about 50% or more in the visible light region. The sheet resistance (surface resistance) of the first electrode is preferably a value of 300Ω / □ or less. The first electrode may be a multilayer. For example, a high refractive index layer such as silicon monoxide or niobium oxide or a reflective layer may be provided.

  The film thickness of the first electrode varies depending on the layer configuration, the electrical resistance of the forming material, and the light transmittance depending on the timely setting, but is preferably set to a value in the range of 5 to 200 nm.

  The first electrode configured as described above is formed by a technique such as vacuum deposition, sputtering, magnetron sputtering, molecular beam epitaxy, cluster ion beam, ion plating, plasma polymerization, or wet coating. The first electrode can form a first electrode having a desired pattern through a pattern mask opened in a desired shape pattern.

  The transparent first electrode is preferably a layer composed mainly of silver and composed of silver or an alloy mainly composed of silver.

  Examples of the method for forming the first electrode include 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, and the like. Examples include a method using a dry process. Among these, the vapor deposition method is preferably applied.

  As an example, the alloy mainly composed of silver (Ag) constituting the first electrode is silver magnesium (AgMg), silver copper (AgCu), silver palladium (AgPd), silver palladium copper (AgPdCu), silver indium (AgIn). Etc.

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

  Further, the first electrode preferably has a thickness in the range of 4 to 15 nm. A thickness of 15 nm or less is preferable because the absorption component and reflection component of the layer are kept low, and the light transmittance of the gas barrier layer is maintained. Further, when the thickness is 4 nm or more, the conductivity of the layer is also ensured.

  When a layer composed mainly of silver is formed as the first electrode, another conductive layer containing Pd or the like, or an organic layer such as a nitrogen compound or a sulfur compound is used as the base layer of the first electrode. It may be formed. By forming the base layer, it is possible to improve the film formation of a layer composed mainly of silver, to reduce the resistivity of the first electrode, and to improve the light transmittance of the first electrode.

[6] Light-Emitting Unit The organic EL device of the present invention is characterized by having at least two or more light-emitting units. Examples of the configuration of each light-emitting unit include the following configurations.

  Below, the typical example of a structure of a light emission unit is shown. Here, the light emitting unit collectively refers to a functional layer existing between an anode (anode) and a cathode (cathode).

(I) (anode (anode) side) / hole injection transport layer / light emitting layer / electron injection transport layer / (intermediate electrode or cathode (cathode) side)
(Ii) (anode (anode) side) / hole injection transport layer / light emitting layer / hole blocking layer / electron injection transport layer / (intermediate electrode or cathode (cathode) side)
(Iii) (anode (anode) side) / hole injection / transport layer / electron blocking layer / light emitting layer / hole blocking layer / electron injection / transport layer / (intermediate electrode or cathode (cathode) side)
(Iv) (anode (anode) side) / hole injection layer / hole transport layer / light emitting layer / electron transport layer / electron injection layer / (intermediate electrode or cathode (cathode) side)
(V) (anode (anode) side) / hole injection layer / hole transport layer / light emitting layer / hole blocking layer / electron transport layer / electron injection layer / (intermediate electrode or cathode (cathode) side)
(Vi) (anode (anode) side) / hole injection layer / hole transport layer / electron blocking layer / light emitting layer / hole blocking layer / electron transport layer / electron injection layer / (intermediate electrode or cathode (cathode) side) )
A non-light emitting intermediate layer may be provided between the light emitting layers. The intermediate layer may be a charge generation layer or a multi-photon unit configuration.

  As for the outline of the light emitting unit applicable to the present invention, for example, JP2013-157634A, JP2013-168552A, JP2013-177361A, JP2013-187221A, JP2013-2013A. 191644, JP2013-191804, JP2013-225678, JP2013-235994, JP2013-243234, JP2013-243236, JP2013-242366. JP, 2013-243371, JP 2013-245179, JP 2014-003249, JP 2014-003299, JP 2014-013910, JP 2014-014933 JP, 2014-017494, A It can be mentioned configurations described in.

<Light emitting layer>
The light emitting layer constituting the light emitting unit preferably has a structure containing a light emitting material, and the light emitting material is preferably a phosphorescent compound or a fluorescent compound.

  This light emitting layer is a layer that emits light by recombination of electrons injected from the electrode or the electron transport layer and holes injected from the hole transport layer, and the light emitting portion is in the layer of the light emitting layer. Alternatively, it may be the interface between the light emitting layer and the adjacent layer.

  Such a light emitting layer is not particularly limited in its configuration as long as the contained 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, it is preferable to have a non-light emitting intermediate layer between the light emitting layers.

  The total thickness of the light emitting layers 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. In addition, the sum total of the thickness of a light emitting layer is the thickness also including the said intermediate | middle layer, when a nonluminous intermediate | middle layer exists between light emitting layers.

  For the light emitting layer as described above, a light emitting material and a host compound, which will be described later, may be formed by a known method such as a vacuum deposition method, a spin coating method, a casting method, an LY method (Langmuir Brodget, Lxngmuir Broadgett method) and an ink jet method. Can be formed.

  In the light emitting layer, a plurality of light emitting materials may be mixed, and a phosphorescent light emitting material and a fluorescent light emitting material (also referred to as a fluorescent dopant or a fluorescent compound) may be mixed and used in the same light emitting layer. The structure of the light-emitting layer preferably includes a host compound (also referred to as a light-emitting host) and a light-emitting material (also referred to as a light-emitting dopant compound) and emits light from the light-emitting material.

(Host compound)
As the host compound contained in the light emitting layer, a compound having a phosphorescence quantum yield of phosphorescence emission at room temperature (25 ° C.) of less than 0.1 is preferable. Further, the phosphorescence quantum yield is preferably less than 0.01. Moreover, it is preferable that the volume ratio in the layer is 50% or more among the compounds contained in a light emitting layer.

  As the host compound, a known host compound may be used alone, or a plurality of types of host compounds may be used. 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. In addition, by using a plurality of kinds of light emitting materials described later, it is possible to mix different light emission, thereby obtaining an arbitrary light emission color.

  The host compound used in the light emitting layer 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 (evaporation polymerizable light emitting host). )

  Examples of the host compound applicable to the present invention include, for example, JP-A Nos. 2001-257076, 2001-357777, 2002-8860, 2002-43056, 2002-105445, 2002-352957, 2002-231453, 2002-234888, 2002-260861, 2002-305083, US Patent Application Publication No. 2005/0112407, US Patent Application Publication No. 2009/0030202, International Publication No. 2001/039234, International Publication No. 2008/056746, International Publication No. 2005/089025, International Publication No. 2007/063754, International Publication No. 2005/030900, International Publication 2009 No. 086028, WO 2012/023947, can be mentioned JP 2007-254297, JP-European compounds described in Japanese Patent No. 2034538 Pat like.

(Luminescent material)
As the light-emitting material that can be used in the present invention, a phosphorescent compound (also referred to as a phosphorescent compound, a phosphorescent material, or a phosphorescent dopant) and a fluorescent compound (both a fluorescent compound or a fluorescent material) are used. Say).

  The phosphorescent compound is a compound in which light emission is observed during the deactivation process from the excited triplet state to the ground state, specifically, a compound that emits phosphorescence at room temperature (25 ° C.), Although the phosphorescence quantum yield is defined as a compound having a phosphorescence quantum yield of 0.01 or more at 25 ° C., the preferred phosphorescence quantum yield is 0.1 or more.

  The phosphorescence quantum yield can be measured by the method described in Spectroscopic II, page 398 (1992 edition, Maruzen) of Experimental Chemistry Course 4 of the 4th edition. The phosphorescence quantum yield in the solution can be measured using various solvents, but when using a phosphorescent compound in the present invention, the phosphorescence quantum yield is 0.01 or more in any solvent. Should be achieved.

  The phosphorescent compound can be appropriately selected from known compounds used for the light emitting layer of a general organic EL device, but preferably contains a group 8-10 metal in the periodic table of elements. More preferred are iridium compounds, more preferred are iridium compounds, osmium compounds, platinum compounds (platinum complex compounds) or rare earth complexes, and most preferred are iridium compounds.

  In the present invention, at least one light emitting layer may contain two or more phosphorescent compounds, and the concentration ratio of the phosphorescent compounds in the light emitting layer varies in the thickness direction of the light emitting layer. It may be an embodiment.

  Specific examples of known phosphorescent compounds 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 /. Examples thereof include compounds described in US Patent No. 0202194, US Patent Application Publication No. 2007/0087321, US Patent Application Publication No. 2005/0244673, and the like.

  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. 2009/000673, US Pat. No. 7,332,232, US Patent Application Publication No. 2009/0039776, US Pat. No. 6,687,266, US Patent Application Publication No. 2006/0008670, US Patent Application Publication No. 2008/0015355, US Pat. No. 7,396,598, US Patent Application Publication No. 2003/0138667, US Pat. No. 7090928 And the like.

  Also, 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. 2006/056418, International Publication No. 2005/123873, International Publication No. 2005/123873, International Publication No. 2006/082742, US Patent Application Publication No. 2005/0260441. U.S. Pat. No. 7,534,505, U.S. Patent Application Publication No. 2007/0190359, U.S. Pat. No. 7,338,722, U.S. Pat. No. 7,279,704, U.S. Patent Application Publication No. 2006/103874, etc. Mention may also be made of the compounds described.

  Furthermore, International Publication No. 2005/076380, International Publication No. 2008/140115, International Publication No. 2011/134013, International Publication No. 2010/086089, International Publication No. 2012/020327, International Publication No. 2011/051404. Further, compounds described in International Publication No. 2011/073149, JP2009-114086, JP2003-81988, JP2002-363552, and the like can also be mentioned.

  In the present invention, preferred phosphorescent compounds include organometallic complexes having Ir as a central metal. More preferably, a complex containing at least one coordination mode of a metal-carbon bond, a metal-nitrogen bond, a metal-oxygen bond, or a metal-sulfur bond is preferable.

The phosphorescent compound described above (also referred to as a phosphorescent metal complex) is described in, for example, Organic Letter, vol. 16, 2579-2581 (2001), Inorganic Chemistry, Vol. 30, No. 8, 1685-1687 (1991), J. Am. Am. Chem. Soc. , 123, 4304 (2001), Inorganic Chemistry, Vol. 40, No. 7, 1704-1711 (2001), Inorganic Chemistry, Vol. 41, No. 12, 3055-3066 (2002) , New Journal of Chemistry. 26, 1171 (2002), European Journal of
It can be synthesized by applying the methods disclosed in Organic Chemistry, Vol. 4, pages 695-709 (2004), and references and the like described in these documents.

  Fluorescent compounds include coumarin dyes, pyran dyes, cyanine dyes, croconium dyes, squalium dyes, oxobenzanthracene dyes, fluorescein dyes, rhodamine dyes, pyrylium dyes, perylene dyes, stilbene dyes. And dyes, polythiophene dyes, and rare earth complex phosphors.

<Functional layer group excluding luminescent layer>
Next, each layer other than the light emitting layer constituting the light emitting unit will be described in the order of the charge injection layer, the hole transport layer, the electron transport layer, and the blocking layer.

(Charge injection layer)
The charge injection layer is a layer provided between the electrode and the light emitting layer in order to lower the driving voltage and improve the light emission luminance. “The organic EL element and its industrialization front line (November 30, 1998, NT. The details are described in Chapter 2, “Electrode Material” (pages 123 to 166) of the second edition of “S. Co., Ltd.”, and there are a hole injection layer and an electron injection layer.

  In general, the charge injection layer is between the anode (anode) and the light emitting layer or hole transport layer if it is a hole injection layer, or the cathode (cathode) and light emitting layer or electron transport layer if it is an electron injection layer. In the present invention, it is preferable to dispose the charge injection layer adjacent to the transparent electrode. When used in a transparent intermediate electrode, it is sufficient that at least one of the adjacent electron injection layer and hole injection layer satisfies the requirements of the present invention.

  The hole injection layer is a layer disposed adjacent to the anode (anode) which is a transparent electrode in order to lower the driving voltage and improve the luminance of light emission. “The organic EL element and its industrialization front line (November 1998) 30th issue of NTS Co., Ltd.) ", Chapter 2, Chapter 2," Electrode Materials "(pp. 123-166).

  The details of the hole injection layer are also described in JP-A-9-45479, JP-A-9-260062, JP-A-8-288069, etc. Examples of the material used for the hole injection layer include: , Porphyrin derivatives, phthalocyanine derivatives, oxazole derivatives, oxadiazole derivatives, triazole derivatives, imidazole derivatives, pyrazoline derivatives, pyrazolone derivatives, phenylenediamine derivatives, hydrazone derivatives, stilbene derivatives, polyarylalkane derivatives, triarylamine derivatives, carbazole derivatives, Inrocarbazole derivatives, isoindole derivatives, acene derivatives such as anthracene and naphthalene, fluorene derivatives, fluorenone derivatives, polyvinylcarbazole, aromatic amines introduced into the main chain or side chain Material or oligomer, polysilane, a conductive polymer or oligomer (e.g., PEDOT (polyethylene dioxythiophene): PSS (polystyrene sulfonic acid), aniline copolymers, polyaniline, polythiophene, etc.) and the like can be mentioned.

  Examples of the triarylamine derivative include benzidine type represented by α-NPD (4,4′-bis [N- (1-naphthyl) -N-phenylamino] biphenyl), and MTDATA (4,4 ′, 4 ″). Examples include a starburst type represented by -tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine) and a compound having fluorene or anthracene in the triarylamine-linked core.

  In addition, hexaazatriphenylene derivatives such as those described in JP-A-2003-519432 and JP-A-2006-135145 can also be used as a hole transport material.

  The electron injection layer is a layer provided between the intermediate electrode or the second electrode (cathode) and the light emitting layer in order to lower the driving voltage and improve the light emission luminance. (November 30, 1998, issued by NTS Corporation) ”, Volume 2, Chapter 2,“ Electrode Materials ”(pages 123-166).

  The details of the electron injection layer are described in JP-A-6-325871, JP-A-9-17574, JP-A-10-74586, and the like. Specific examples of materials preferably used for the electron injection layer are as follows. Metals represented by strontium and aluminum, alkali metal compounds represented by lithium fluoride, sodium fluoride, potassium fluoride, etc., alkali metal halide layers represented by magnesium fluoride, calcium fluoride, etc. Examples thereof include an alkaline earth metal compound layer typified by magnesium, a metal oxide typified by molybdenum oxide and aluminum oxide, and a metal complex typified by lithium 8-hydroxyquinolate (Liq). Moreover, when the transparent electrode in this invention is a cathode (cathode), organic materials, such as a metal complex, are used especially suitably. The electron injection layer is desirably a very thin film, and although depending on the constituent material, the layer thickness is preferably in the range of 1 nm to 10 μm.

(Hole transport layer)
The hole transport layer is made of a hole transport material having a function of transporting holes. In a broad sense, the hole injection layer and the electron blocking layer also have the function of a hole transport layer. The hole transport layer 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, pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, Examples include stilbene derivatives, silazane derivatives, aniline copolymers, conductive polymer oligomers, and thiophene oligomers.

  As the hole transport material, those described above can be used, but porphyrin compounds, aromatic tertiary amine compounds and styrylamine compounds can be used, and in particular, aromatic tertiary amine compounds can be used. preferable.

  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 (abbreviation: 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 -Tolylaminophenyl) -4-phenylcyclohexane, bis (4-dimethylamino-2-methylphenyl) phenylmethane, bis (4-di-p-tolylaminophenyl) phenylmethane, N, N'-diphenyl-N, '-Di (4-methoxyphenyl) -4,4'-diaminobiphenyl, N, N, N', N'-tetraphenyl-4,4'-diaminodiphenyl ether, 4,4'-bis (diphenylamino) c Audriphenyl, N, N, N-tri (p-tolyl) amine, 4- (di-p-tolylamino) -4 '-[4- (di-p-tolylamino) styryl] stilbene, 4-N, N- Examples include diphenylamino- (2-diphenylvinyl) benzene, 3-methoxy-4′-N, N-diphenylaminostilbenzene, N-phenylcarbazole and the like.

  For the hole transport layer, the hole transport material may be formed 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, and an LY method (Langmuir Brodget, Lxngmuir Brodgett method). Thus, it can be formed by thinning. Although there is no restriction | limiting in particular about the layer thickness of a positive hole transport layer, Usually, about 5 nm-5 micrometers, Preferably it is the range of 5-200 nm. The hole transport layer may have a single layer structure composed of one or more of the above materials.

  Moreover, p property can also be made high by doping the material of a positive hole transport layer with an impurity. Examples thereof include JP-A-4-297076, JP-A-2000-196140, 2001-102175 and J.P. Appl. Phys. 95, 5773 (2004), and the like.

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

(Electron transport layer)
The electron transport layer is made of a material having a function of transporting electrons, and in a broad sense, an electron injection layer and a hole blocking layer are also included in the electron transport layer. The electron transport layer can be provided as a single layer structure or a stacked structure of a plurality of layers.

  In the electron transport layer having a single-layer structure and the electron transport layer 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 is used as an electron transporting material. What is necessary is just to have the function to transmit. 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. Furthermore, 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 can also be used as a material for the electron transport layer. it can. Furthermore, a polymer material in which these materials are introduced into a polymer chain, or a polymer material having these materials as a polymer main chain can also be used.

In addition, metal complexes of 8-quinolinol derivatives such as tris (8-quinolinol) aluminum (abbreviation: 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 (abbreviation: Znq), etc. and the central metal of these metal complexes A metal complex replaced with In, Mg, Cu, Ca, Sn, Ga, or Pb can also be used as a material for the electron transport layer.

  The electron transport layer 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 inkjet method, and an LY method. Although there is no restriction | limiting in particular about the layer thickness of an electron carrying layer, Usually, about 5 nm-5 micrometers, Preferably it exists in the range of 5-200 nm. The electron transport layer may have a single structure composed of one or more of the above materials.

  In the present invention, the light scattering layer (light scattering layer 1) according to the present invention also serves as the electron transport layer for productivity and thinning due to a reduction in the number of layers.

  In addition to the electron transporting material, the light scattering particles (nanoparticles having high refractive index, anisotropic fine particles) are preferably contained so as to obtain a light scattering effect. Furthermore, if necessary, an electron transport layer to which no scattering particles are added can be deposited on the electron transport layer to which scattering particles are added.

(Blocking layer)
Examples of the blocking layer include a hole blocking layer and an electron blocking layer, which are provided as necessary. For example, it is described in JP-A Nos. 11-204258, 11-204359, and “Organic EL elements and their forefront of industrialization” (issued by NTT, Inc. on November 30, 1998). Hole blocking (hole block) layer and the like.

  The hole blocking layer has a function of an electron transport layer 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 an electron carrying layer can be used as a hole-blocking layer as needed. The hole blocking layer is preferably provided adjacent to the light emitting layer.

  On the other hand, the electron blocking layer has a function of a hole transport layer in a broad sense. The electron blocking layer is made of a material that has the ability to transport holes and has a very small ability to transport electrons. By blocking holes while transporting holes, the probability of recombination of electrons and holes is improved. Can be made. Moreover, the structure of a positive hole transport layer can be used as an electron blocking layer as needed. The layer thickness of the hole blocking layer applied to the present invention is preferably in the range of 3 to 100 nm, more preferably in the range of 5 to 30 nm.

[7] Transparent intermediate electrode In the organic EL device of the present invention, a plurality of light-emitting units are formed between an anode (anode) and a cathode (cathode), and the plurality of light-emitting units are electrically connected. It takes a structure separated by a transparent intermediate electrode having independent connection terminals to obtain.

  The material that can be used as the transparent intermediate electrode is the same as that of the transparent first electrode described above, and among them, an electrode composed of silver or an alloy containing silver as a main component is preferable. It is a preferable embodiment that the base layer containing the organic compound having at least a nitrogen atom or a sulfur atom as described above is provided at a position adjacent to the electrode.

[8] Second electrode The second electrode is an electrode that functions as an anode or a cathode. In the case of a cathode, the second electrode is an electrode film that functions to supply electrons to the functional layer group and the light emitting layer, and has a small work function ( 4 eV or less) An electrode material made of a metal (referred to as an electron injecting metal), an alloy, an electrically conductive compound, and a mixture thereof is used. Specifically, gold, aluminum, silver, magnesium, lithium, magnesium / copper mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, indium, lithium / aluminum mixture, rare earth metal, ITO, ZnO, TiO Oxide semiconductors such as ₂ and SnO ₂ .

Among these, a mixture of an electron injecting metal and a second metal having a work function value larger and more stable than that of the electron injecting metal, for example, magnesium / Silver mixtures, magnesium / aluminum mixtures, magnesium / indium mixtures, aluminum / aluminum oxide (Al ₂ O ₃ ) mixtures, lithium / aluminum mixtures, aluminum and the like are preferred.

  The second electrode can be produced by forming a thin film of these conductive materials by a method such as vapor deposition or sputtering. The sheet resistance as the second electrode is preferably several hundred Ω / □ or less, and the film thickness is usually selected in the range of 5 nm to 5 μm, preferably 5 to 200 nm.

  Note that the organic EL element of the present invention may be configured by selecting an electrode having good light reflectivity in the case of a bottom emission method in which emitted light is extracted from the anode (anode) side.

[9] Sealing member As a sealing means used for sealing the organic EL device of the present invention, the light emitting unit and the electrode group are solid-sealed with an adhesive on the transparent substrate (laminated sealing). Stop).

  As a sealing member, it is comprised from the resin material (resin sealing layer) for joining a board | substrate and a sealing member.

  In addition to the resin material (resin sealing layer), an inorganic material (inorganic sealing layer) may be used. For example, after covering a transparent 1st electrode, a light emitting unit layer, and a 2nd electrode with an inorganic sealing layer, it is good also as a structure which joins a sealing member and a board | substrate with a resin sealing layer.

(Resin sealing layer)
The resin sealing layer is used for fixing the sealing member to the transparent substrate side. Moreover, it is used as a sealing agent for sealing the transparent first electrode, the light emitting unit layer, and the second electrode sandwiched between the sealing member and the transparent substrate.

  In order to join the sealing member to the substrate, it is preferable to bond using an arbitrary curable resin sealing layer.

  For the resin sealing layer, a suitable adhesive can be appropriately selected from the viewpoint of improving the adhesion with an adjacent sealing member or transparent substrate.

  As such a resin sealing layer, it is preferable to use a thermosetting resin.

  As the thermosetting adhesive, for example, a resin mainly composed of a compound having an ethylenic double bond at the molecular end or side chain and a thermal polymerization initiator can be used.

  More specifically, a thermosetting adhesive made of an epoxy resin, an acrylic resin, or the like can be used. Moreover, according to the bonding apparatus and hardening processing apparatus which are used by the manufacturing process of an organic EL element, you may use a fusion type thermosetting adhesive.

  Moreover, it is preferable to use a photocurable resin as such a resin sealing layer.

  For example, photo-radically polymerizable resins mainly composed of various (meth) acrylates such as polyester (meth) acrylate, polyether (meth) acrylate, epoxy (meth) acrylate, polyurethane (meth) acrylate, epoxy, vinyl ether, etc. Examples thereof include a cationic photopolymerizable resin mainly composed of a resin and a thiol / ene addition type resin. Among these photo-curing resins, an epoxy resin-based photo-cationic polymerizable resin having a low shrinkage of the cured product, a small outgas, and excellent long-term reliability is preferable.

  Moreover, as such a resin sealing layer, a chemical curing type (two-component mixed) resin can be used. Hot melt polyamide, polyester, and polyolefin can also be used. Moreover, a cationic curing type ultraviolet curing epoxy resin can be used.

  In addition, the organic material which comprises an organic EL element may deteriorate with heat processing. For this reason, it is preferable to use a resin material that can be adhesively cured from room temperature to 80 ° C.

(Inorganic sealing layer)
The inorganic sealing layer is preferably formed of a compound such as an inorganic oxide, an inorganic nitride, or an inorganic carbide having high sealing properties.

Specifically, it is formed of SiO _x , Al ₂ O ₃ , In ₂ O ₃ , TiO _x , ITO (indium tin oxide), AlN, Si ₃ N ₄ , SiO _x N, TiO _x N, SiC, or the like. can do.

  The inorganic sealing layer can be formed by a known method such as a sol-gel method, a vapor deposition method, CVD, ALD (Atomic Layer Deposition), PVD, or a sputtering method.

  In addition, the inorganic sealing layer is formed by selecting conditions such as an organometallic compound, a decomposition gas, a decomposition temperature, and an input power as raw materials (also referred to as raw materials) in an atmospheric pressure plasma method. Compositions such as mixtures of inorganic carbides, inorganic nitrides, inorganic sulfides, inorganic halides, and the like such as inorganic oxides or inorganic oxynitrides and inorganic oxide halides can be made.

  For example, if a silicon compound is used as a raw material compound and oxygen is used as the decomposition gas, silicon oxide is generated. Further, if silazane or the like is used as a raw material compound, silicon oxynitride is generated. This is because highly active charged particles and active radicals exist in the plasma space at a high density, so that multistage chemical reactions are accelerated very rapidly in the plasma space, and the elements in the plasma space are thermodynamically This is because it is converted into a very stable compound in a very short time.

  As long as the raw material for forming such an inorganic sealing layer is a silicon compound, it may be in a gas, liquid, or solid state at normal temperature and pressure. In the case of gas, it can be introduced into the discharge space as it is, but in the case of liquid or solid, it is used after being vaporized by means such as heating, bubbling, decompression or ultrasonic irradiation.

  Moreover, you may dilute and use by a solvent and can use organic solvents, such as methanol, ethanol, n-hexane, and these mixed solvents. In addition, since these dilution solvents are decomposed | disassembled into molecular form and atomic form during a plasma discharge process, the influence can be almost disregarded.

  Examples of such silicon compounds include silane, tetramethoxysilane, tetraethoxysilane, tetra n-propoxysilane, tetraisopropoxysilane, tetra n-butoxysilane, tetrat-butoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, Diethyldimethoxysilane, diphenyldimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, phenyltriethoxysilane, (3,3,3-trifluoropropyl) trimethoxysilane, hexamethyldisiloxane, bis (dimethylamino) dimethylsilane Bis (dimethylamino) methylvinylsilane, bis (ethylamino) dimethylsilane, N, O-bis (trimethylsilyl) acetamide, bis (trimethylsilyl) carbodiimide, die Ruaminotrimethylsilane, dimethylaminodimethylsilane, hexamethyldisilazane, hexamethylcyclotrisilazane, heptamethyldisilazane, nonamethyltrisilazane, octamethylcyclotetrasilazane, tetrakisdimethylaminosilane, tetraisocyanatosilane, tetramethyldisilazane , Tris (dimethylamino) silane, triethoxyfluorosilane, allyldimethylsilane, allyltrimethylsilane, benzyltrimethylsilane, bis (trimethylsilyl) acetylene, 1,4-bistrimethylsilyl-1,3-butadiyne, di-t-butylsilane, 1,3-disilabutane, bis (trimethylsilyl) methane, cyclopentadienyltrimethylsilane, phenyldimethylsilane, phenyltrimethylsilane, pro Rugyltrimethylsilane, tetramethylsilane, trimethylsilylacetylene, 1- (trimethylsilyl) -1-propyne, tris (trimethylsilyl) methane, tris (trimethylsilyl) silane, vinyltrimethylsilane, hexamethyldisilane, octamethylcyclotetrasiloxane, tetramethyl Examples thereof include cyclotetrasiloxane, hexamethylcyclotetrasiloxane, M silicate 51, and the like.

  In addition, as a decomposition gas for decomposing these silicon-containing source gases to obtain an inorganic sealing layer, hydrogen gas, methane gas, acetylene gas, carbon monoxide gas, carbon dioxide gas, nitrogen gas, ammonia gas, suboxide Examples thereof include nitrogen gas, nitrogen oxide gas, nitrogen dioxide gas, oxygen gas, water vapor, fluorine gas, hydrogen fluoride, trifluoroalcohol, trifluorotoluene, hydrogen sulfide, sulfur dioxide, carbon disulfide, and chlorine gas.

  By appropriately selecting the raw material gas containing silicon and the decomposition gas, an inorganic sealing layer containing silicon oxide, nitride, carbide or the like can be obtained.

  In the atmospheric pressure plasma method, a discharge gas that tends to be in a plasma state is mainly mixed with these reactive gases, and the gas is sent to a plasma discharge generator.

  As such a discharge gas, nitrogen gas and / or 18th group atom of the periodic table, specifically, helium, neon, argon, krypton, xenon, radon, etc. are used. Among these, nitrogen, helium, and argon are preferably used.

  The discharge gas and the reactive gas are mixed and supplied to an atmospheric pressure plasma discharge generator (plasma generator) as a thin film forming (mixed) gas to form a film. Although the ratio of the discharge gas and the reactive gas varies depending on the properties of the film to be obtained, the reactive gas is supplied with the ratio of the discharge gas being 50% or more with respect to the entire mixed gas.

  Especially, since the element can be thinned, a polymer substrate in the form of a thin film can be preferably used as the sealing member.

The film-like polymer substrate has an oxygen permeability of 1 × 10 ⁻³ ml / (m ² · 24 h · atm) or less measured by a method according to JIS K 7126-1987, and a method according to JIS K 7129-1992. It is preferable that the water vapor permeability (25 ± 0.5 ° C., relative humidity (90 ± 2)%) measured in (1) is 1 × 10 ⁻³ g / (m ² · 24 h) or less.

  Further, the above substrate material may be processed into a concave plate shape and used as a sealing member. In this case, the substrate member described above is subjected to processing such as sand blasting or chemical etching to form a concave shape.

  Moreover, not only this but a metal material may be used. Examples of the metal material include one or more metals or alloys selected from the group consisting of stainless steel, iron, copper, aluminum, magnesium, nickel, zinc, chromium, titanium, molybdenum, silicon, germanium, and tantalum. By using such a metal material as a sealing member in the form of a thin film, the entire light-emitting panel provided with the organic electroluminescent element can be thinned.

(Sealing member)
The sealing member covers the organic EL element, and a plate-like (film-like) sealing member is fixed to the transparent substrate side by a sealing layer.

  Specific examples of the plate-like (film-like) sealing member include a glass substrate and a polymer substrate, and these substrate materials may be used in the form of a thin film.

  Examples of the glass substrate include soda-lime glass, barium / strontium-containing glass, lead glass, aluminosilicate glass, borosilicate glass, barium borosilicate glass, and quartz.

  Examples of the polymer substrate include polycarbonate, acrylic, polyethylene terephthalate, polyether sulfide, and polysulfone.

  Further, as the sealing member, it is preferable to use a metal foil on which a resin film is laminated (polymer film). A metal foil laminated with a resin film cannot be used as a substrate on the light extraction side, but is a sealing material with low cost and low moisture permeability. For this reason, it is suitable as a sealing member not intended for light extraction.

  The metal foil refers to a metal foil or film formed by rolling or the like, unlike a metal thin film formed by sputtering or vapor deposition, or a conductive film formed from a fluid electrode material such as a conductive paste. .

  As metal foil, there is no limitation in particular in the kind of metal, for example, copper (Cu) foil, aluminum (Al) foil, gold (Au) foil, brass foil, nickel (Ni) foil, titanium (Ti) foil, copper alloy Examples thereof include foil, stainless steel foil, tin (Sn) foil, and high nickel alloy foil. Among these various metal foils, a particularly preferable metal foil is an Al foil.

  The thickness of the metal foil is preferably in the range of 6 to 50 μm. When it is in the range of 6 to 50 μm, it is possible to prevent the generation of pinholes during use depending on the material used for the metal foil, and to obtain the required gas barrier properties (moisture permeability, oxygen permeability).

  For example, polyethylene resin, polypropylene resin, polyethylene terephthalate resin, polyamide resin, ethylene-vinyl alcohol copolymer resin, ethylene-vinyl acetate copolymer resin, acrylonitrile-butadiene copolymer resin, cellophane resin, vinylon Resin, vinylidene chloride resin and the like can be used.

  Resins such as polypropylene resin and nylon resin may be stretched and further coated with vinylidene chloride resin. In addition, the polyethylene resin may be either low density or high density.

The sealing member 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 measured by a method according to JIS K 7129-1992. The water vapor permeability (25 ± 0.5 ° C., relative humidity (90 ± 2)%) is preferably 1 × 10 ⁻³ g / (m ² · 24 h) or less.

  Further, the above substrate material may be processed into a concave plate shape and used as a sealing member. In this case, the substrate member described above is subjected to processing such as sand blasting or chemical etching to form a concave shape.

  Moreover, not only this but a metal material may be used. Examples of the metal material include one or more metals or alloys selected from the group consisting of stainless steel, iron, copper, aluminum, magnesium, nickel, zinc, chromium, titanium, molybdenum, silicon, germanium, and tantalum. By using such a metal material as a sealing member in the form of a thin film, the entire light-emitting panel provided with the organic EL element can be thinned.

[10] Other components (extraction electrode)
The extraction electrode is for electrically connecting the transparent first electrode, the transparent intermediate electrode and the second electrode to an external power source, and the material thereof is not particularly limited, and a known material can be suitably used. However, 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)
The auxiliary electrode is provided for the purpose of reducing the resistance of the transparent electrode, and is provided in contact with the transparent first electrode. 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 a method for forming such an auxiliary electrode include a vapor deposition method, a sputtering method, a printing method, an ink jet method, and an aerosol jet method. 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.

(Protective film, protective plate)
The protective film or the protective plate is for mechanically protecting the organic EL element, and particularly when the sealing material is a sealing film, the mechanical protection for the organic EL element is not sufficient. It is preferable to provide such a protective film or protective plate.

  A glass plate, a polymer plate, a resin film thinner than this, a metal plate, a metal film thinner than this, a polymer material film, or a metal material film is applied to the above protective film or protective plate. Among these, it is particularly advantageous for transparency, and it is preferable to use a resin film because it is lightweight and thin.

[11] Manufacturing method of organic EL element The manufacturing method of the organic EL element of the present invention has, as a minimum configuration, a transparent first electrode (anode), a first light emitting unit, a transparent intermediate electrode, and a second light emission on a transparent substrate. The unit, the second electrode (cathode (cathode)) and the sealing member are laminated to form a laminate.

  First, a transparent substrate is prepared, and on the transparent substrate, a thin film made of a desired electrode material, for example, an anode (anode) material is 1 μm or less, preferably 10 to 200 nm. An anode (anode) is formed by a method such as vapor deposition or sputtering. At the same time, a connection electrode portion connected to an external power source is formed at the end of the anode (anode).

  Next, a hole injection layer and a hole transport layer constituting the first light emitting unit, a light emitting layer, an electron transport layer constituting the functional layer group, an electron injection layer, and the like are sequentially laminated thereon.

The formation of each of these layers includes spin coating, casting, inkjet, vapor deposition, and printing, but vacuum vapor deposition is easy because a homogeneous layer is easily obtained and pinholes are difficult to generate. The method or spin coating method is particularly preferred. Further, different formation methods may be applied for each layer. When employing a vapor deposition method for forming each of these layers, the vapor deposition conditions vary depending on the type of compound used, but generally a boat heating temperature of 50 to 450 ° C. and a degree of vacuum of 1 × 10 ⁻⁶ to 1 × 10 ⁻² Pa. It is desirable to appropriately select the respective conditions within the ranges of the deposition rate of 0.01 to 50 nm / second, the substrate temperature of −50 to 300 ° C., and the layer thickness of 0.1 to 5 μm.

  After forming the first light emitting unit as described above, a transparent intermediate electrode is formed on the upper portion by an appropriate forming method such as a vapor deposition method or a sputtering method. Next, the second light emitting unit is laminated in the same manner, and the second electrode is insulated from the anode (anode) by the light emitting unit group, and the terminal part is drawn from the upper side of the light emitting unit group to the periphery of the transparent substrate. A pattern is formed.

  After the formation of the second electrode, these are sealed with a sealing member. At that time, the anode (anode, cathode) and intermediate electrode terminal portions are exposed, and the transparent substrate is sealed so as to cover at least the light emitting unit group.

  In the manufacture of an organic EL element, for example, each electrode of the organic EL element is electrically connected to a light emitting element driving circuit unit or a touch detection circuit unit, and an electrical connection member that can be used at that time Although there is no restriction | limiting in particular if it is a member provided with electroconductivity, It is a preferable aspect that it is an anisotropic conductive film (ACF), an electroconductive paste, or a metal paste.

  Examples of the anisotropic conductive film (ACF) include a layer having fine conductive particles having conductivity mixed in a thermosetting resin. The conductive particle-containing layer that can be used in the present invention is not particularly limited as long as it is a layer containing conductive particles as an anisotropic conductive member, and can be appropriately selected according to the purpose. There is no restriction | limiting in particular as electroconductive particle which can be used as an anisotropic conductive member, According to the objective, it can select suitably, For example, a metal particle, a metal covering resin particle, etc. are mentioned. Examples of commercially available ACFs include low-temperature curable ACFs that can also be applied to resin films, such as MF-331 (manufactured by Hitachi Chemical).

  Examples of the metal particles include nickel, cobalt, silver, copper, gold, palladium, and the like. As the metal-coated resin particles, for example, the surface of the resin core is any one of nickel, copper, gold, and palladium. The metal paste may be a commercially available metal nanoparticle paste.

[12] An example of the circuit of the organic EL element of the present invention The organic EL element of the present invention preferably has a circuit that is independently driven by two or three power supplies, and the polarity of the plurality of transparent intermediate electrodes However, it is easy to design and control that the layers are laminated in the repeating order of positive and negative or negative and positive in order from the transparent substrate side, and an organic electroluminescence device capable of freely changing the emission color is provided. From this viewpoint, this is a preferred embodiment.

[13] Use of organic EL element 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, The light source of an optical sensor can be used by taking advantage of the double-sided emission characteristics.

  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 this case, with the recent increase in the size of lighting devices and displays, the light emitting surface may be enlarged by so-called tiling, in which light emitting panels provided with organic EL elements are joined together in a plane.

  The driving 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, an illumination device will be described as an example.

[Lighting device]
The lighting device using the organic EL element of the present invention may be designed such that each organic EL element having the above-described configuration has a resonator structure. Examples of the purpose of use of the organic EL element configured as a resonator structure include, but are not limited to, a light source of an optical storage medium, a light source of an electrophotographic copying machine, a light source of an optical communication processor, a light source of an optical sensor, and the like. . Moreover, you may use for the said use by making a laser oscillation.

  Note that the material used for the organic EL element of the present invention can be applied to an organic EL element that emits white light (also referred to as a white organic EL element). For example, a plurality of light emitting materials can simultaneously emit a plurality of light emission colors to obtain white light emission by color mixing. As described above, the combination of a plurality of emission colors may include three emission maximum wavelengths of the three primary colors of red, green, and blue as described above, or use the relationship of complementary colors such as blue and yellow, blue green and orange, etc. It may be one containing the two emission maximum wavelengths.

  In addition, a combination of light emitting materials for obtaining a plurality of emission colors is a combination of a plurality of phosphorescent or fluorescent materials, a light emitting material that emits fluorescence or phosphorescence, and excitation of light from the light emitting materials. Any combination with a pigment material that emits light as light may be used, but in a white organic EL element, a combination of a plurality of light-emitting dopants may be used.

  Such a white organic EL element is different from a configuration in which organic EL elements each emitting light are individually arranged in parallel in an array to obtain white light emission, and the organic EL element itself emits white light. For this reason, a mask is not required for film formation of most layers constituting the element, and for example, an electrode film can be formed on one side by vapor deposition, casting, spin coating, ink jet, printing, etc., and productivity is improved. To do.

  In addition, the light emitting material used for the light emitting layer of such a white organic EL element is not particularly limited. For example, in the case of a backlight in a liquid crystal display element, the light emitting material is adapted to a wavelength range corresponding to CF (color filter) characteristics. Any one of the metal complexes according to the present invention and known light-emitting materials may be selected and combined for whitening.

  If the white organic EL element demonstrated above is used, it is possible to produce the illuminating device which produces substantially white light emission.

  EXAMPLES 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, "mass part" or "mass%" is represented.

Example 1
[Production of Organic EL Element 101]
As an organic EL element of a comparative example, an element was produced with a configuration of transparent substrate / transparent first electrode / first light emitting unit / transparent intermediate electrode / second light emitting unit / second electrode / (sealed).

<Transparent substrate>
A polyester film MELINEX ST504 (manufactured by Teijin DuPont Films Ltd.) having a width of 50 cm and a thickness of 125 μm was prepared as a transparent substrate. This polyester film is degassed for 3 hours by heating to 80 ° C. under a reduced pressure of 1.33 Pa.

  A polysilazane-containing coating solution was applied onto the polyester film, and then subjected to a modification treatment by irradiation with vacuum ultraviolet rays to provide a gas barrier layer, thereby producing a transparent flexible substrate.

(Preparation of polysilazane-containing coating solution)
A dibutyl ether solution containing 20% by mass of non-catalytic perhydropolysilazane (manufactured by AZ Electronic Materials, Aquamica (registered trademark) NN120-20) and an amine catalyst (N, N, N ′, N′-tetramethyl-) Perhydropolysilazane containing 20% by mass of dibutyl ether containing 5% by mass of 1,6-diaminohexane (TMDAH) (manufactured by AZ Electronic Materials Co., Ltd., Aquamica (registered trademark) NAX120-20) In a solvent mixed so that the mass ratio of dibutyl ether and 2,2,4-trimethylpentane is 65:35, the coating solution is mixed so that the solid content of the coating solution is 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 transparent substrate with a spin coater, allowed to stand for 2 minutes, and then heat-treated with a hot plate at 80 ° C. for 1 minute to apply polysilazane coating. A film was formed.

After forming the polysilazane coating film, a vacuum ultraviolet ray irradiation treatment of 6000 mJ / cm ² was performed to form a gas barrier layer.

<Formation of transparent first electrode>
On the gas barrier layer, ITO (Indium Tin Oxide: ITO) having a thickness of 150 nm was formed by sputtering and patterned by photolithography to form a transparent first electrode. The pattern was such that the light emission area was 50 mm square.

<Formation of first light emitting unit>
(Formation of hole injection layer 1: Indicated as HIL in the table, the same shall apply hereinafter)
As a hole injection material, a heating boat containing a compound represented by the following structural formula HI-1 is energized and heated, and a heating boat containing a compound represented by the following structural formula HI-2 is energized and heated to be transparent. A hole injection layer 1 was formed on the first electrode. At this time, by adjusting the energization to each heating boat, the vapor deposition rates of Compound HI-1 and Compound HI-2 were made the same from 0.1 nm / second to 0.2 nm / second, and the film thickness was set to 15 nm.

(Formation of hole transport layer 1: HTL)
Next, the hole-transporting layer 1 was formed on the hole-injecting layer 1 by heating a heated boat containing a compound represented by the following structural formula HT-1 as a hole-transporting material. At this time, the pressure was reduced to a vacuum degree of 1 × 10 ⁻⁴ Pa using a commercially available vacuum deposition apparatus, and then the deposition rate was 0.1 nm / second to 0.2 nm / second, and the film thickness was 50 nm.

(Formation of the light emitting layer 1: EML)
Next, the heating boat containing the host compound H-1 and the heating boat containing the phosphorescent light emitting dopant A-3 (blue light emitting dopant: expressed as B in the table) were energized independently to each other, and the host compound H- 1 and a phosphorescent layer containing phosphorescent dopant A-3 were formed on the hole transport layer. At this time, the energization of the heating boat was adjusted so that the deposition rate was host compound H-1: phosphorescent dopant A-3 = 100: 6. The layer thickness was 30 nm.

(Formation of electron transport layer 1: ETL)
Thereafter, a heating boat containing a compound represented by the following structural formula ET-1 as an electron transporting material and a heating boat containing potassium fluoride were respectively energized independently, and electrons containing ET-1 and potassium fluoride. The transport layer 1 was formed on the light emitting layer 1. At this time, the energization of the heating boat was adjusted so that the deposition rate was ET-1: potassium fluoride = 75: 25. The layer thickness was 30 nm.

(Formation of electron injection layer 1: EIL)
Next, a heating boat containing potassium fluoride as an electron injection material was energized and heated to form an electron injection layer 1 made of potassium fluoride on the electron transport layer 1. At this time, the deposition rate was 0.01 to 0.02 nm / second, and the layer thickness was 1.5 nm.

<Formation of transparent intermediate electrode 1>
On the first light emitting unit, aluminum (Al) and silver (Ag) were placed in a resistance heating boat made of tungsten, respectively, and mounted in the first vacuum chamber. After depressurizing the vacuum chamber to 4 × 10 ⁻⁴ Pa, each of the resistance heating boats is independently energized and heated, and the transparent intermediate electrode layer 1 having a thickness ratio of aluminum (Al) 1 nm and silver (Ag) 12 nm is formed. The transparent intermediate electrode 1 was formed by co-evaporation and patterning by photolithography. The pattern was such that the light emission area was 50 mm square.

<Formation of second light emitting unit>
In the same manner as the formation of the first light emitting unit, the second light emitting unit was formed in the same manner except that the formation of the hole transport layer, the light emitting layer and the electron transport layer was as follows.

(Formation of hole transport layer 2)
In the formation of the first light emitting unit, the hole transport layer 2 was formed in the same manner except that the layer thickness was changed to 30 nm.

(Formation of the light emitting layer 2)
A heating boat containing the host compound H-1, a phosphorescent dopant A-1 (green emitting dopant: indicated as G in the table) and a phosphorescent dopant A-2 (red emitting dopant: indicated as R in the table) Each of the heated boats was energized independently, and a light emitting layer containing the host material H-1 and the phosphorescent light emitting dopants A-1 and A-2 was formed on the hole transport layer by co-evaporation. . At this time, the energization of the heating boat is adjusted so that the vapor deposition rate is the host compound H-1: phosphorescent light emitting dopant A-1: phosphorescent light emitting dopant A-2 = 100: 2: 4. It was adjusted to emit light. The layer thickness was 30 nm.

(Formation of electron transport layer 2)
In the formation of the first light emitting unit, the electron transport layer 2 was formed in the same manner except that the layer thickness was changed to 40 nm.

<Formation of second electrode>
As a second electrode forming material under a vacuum of 5 × 10 ⁻⁴ Pa on the electron injection layer of the second light emitting unit formed as described above, except for the portion that becomes the extraction electrode of the transparent first electrode. A mask pattern was formed using aluminum (Al) so that the emission area was 50 mm square using an evaporation method so as to have an extraction electrode, and a second electrode having a thickness of 100 nm was laminated.

(Cutting)
As described above, each laminate including the second electrode was moved again to a nitrogen atmosphere, and cut to a specified 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 circuit board (base film: polyimide 12.5 μm, rolled copper foil 18 μm, coverlay: polyimide 12 0.5 μm, surface-treated NiAu plating).

  Pressure bonding conditions: Pressure bonding 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 with sealing member)
A thermosetting liquid adhesive (epoxy photo-curing adhesive: Luxtrack LC0629B manufactured by Toagosei Co., Ltd.) is applied to the gas barrier layer side of the produced gas barrier transparent substrate with a thickness of 30 μm, and then coated thereon. A flexible sealing member made of polyethylene terephthalate as a base and vapor-deposited Al ₂ O ₃ at a thickness of 300 nm. The ends of the transparent first electrode, the transparent intermediate electrode, and the second electrode of the organic EL element are outside. The bottom surface emission type organic EL element 101 was produced by continuously superposing the adhesive surface of the sealing member and the functional layer surface of the organic EL element so as to be exposed to each other and bonding them by a dry laminating method.

  The sealing step is performed under atmospheric pressure and in a nitrogen atmosphere with a moisture content of 1 ppm or less, in accordance with JIS B 9920, with a measured cleanliness of class 100, a dew point temperature of −80 ° C. or less, and an oxygen concentration of 0.8 ppm or less. At atmospheric pressure.

[Production of Organic EL Element 102]
In the production of the organic EL element 101, an organic EL element 102 was produced in the same manner except that the thickness of the hole transport layer 1 of the first light emitting unit was changed to 70 nm.

[Production of Organic EL Element 103]
In the production of the organic EL element 101, the organic EL element 103 was produced in the same manner except that the thickness of the hole transport layer 2 of the second light emitting unit was changed to 60 nm and the thickness of the electron transport layer 2 was changed to 50 nm.

[Production of Organic EL Element 104]
In the production of the organic EL element 101, the organic EL element 104 was produced in the same manner as shown in FIG. 3 except that the electron transport layer 1 of the first light emitting unit was changed to the electron transport / light scattering layer 1 by the following procedure. did.

(Electron transport / light scattering layer 1: ET / LSL)
A coating solution for the electron transport / light scattering layer 1 was prepared as described below, and coated with a spin coater under conditions of 1500 rpm and 30 seconds. Further, the electron transport / light scattering layer 1 was provided by heating at a substrate surface temperature of 120 ° C. for 30 minutes. The film thickness was 30 nm when it applied and measured on the conditions prepared with the board | substrate prepared separately.

(Coating liquid for electron transport / light scattering layer 1)
2,2,3,3-tetrafluoro-1-propanol 100 g
ET-1 0.75g
Anisotropic fine particle dispersion (TI-T40A-01, manufactured by Kotobuki Industries Co., Ltd.) 12% by volume
TI-T40A-01 manufactured by Kotobuki Industries Co., Ltd .: TiO ₂ , needle-like (anisotropic), minor axis median diameter 15 nm, aspect ratio 3-10
[Production of Organic EL Element 105]
In the production of the organic EL element 104, the organic EL element 105 was produced in the same manner except that the thickness of the electron transport layer of the first light emitting unit was changed to 70 nm.

[Production of Organic EL Element 106]
In the production of the organic EL element 104, the organic EL element 106 was produced in the same manner except that the layer thickness of the hole transport layer 2 of the second light emitting unit was changed to 60 nm and the layer thickness of the electron transport layer 2 was changed to 50 nm.

[Production of Organic EL Element 107]
In the production of the organic EL element 104, the layer thickness of the hole transport layer 1 of the first light emitting unit is changed to 40 nm, the layer thickness of the hole transport layer 2 of the second light emitting unit is 50 nm, and the layer thickness of the electron transport layer 2 The organic EL element 107 was produced in the same manner except that the thickness was changed to 25 nm.

≪Evaluation≫
The following evaluation was performed using the produced organic EL elements 101 to 107.

[1] Current efficiency (cd / A)
The current efficiency (cd / A) of each organic EL element was evaluated using a spectral radiance meter CS-1000 (manufactured by Konica Minolta Sensing) under an environment of 23 ° C. and 55% RH. The current efficiency (cd / A) is expressed as a relative value with the efficiency of the organic EL element 101 at a luminance of 1000 cd / m ² as 100.

  The current efficiency of the first light emitting unit was measured with blue light at 300 nits.

  The current efficiency of the second light emitting unit was measured at 700 nits of yellow light.

  White 4000K means white light having a color temperature of 4000K (Kelvin), and the first light emitting unit (blue light) and the second light emitting unit (yellow light) are simultaneously emitted so that the total becomes 1000 nits at 4000K. The light emission of the two light emitting units was adjusted and measured.

[2] Front luminance Under the environment of 23 ° C. and 55% RH, using a spectral radiance meter CS-1000 (manufactured by Konica Minolta Sensing), the front surface of each sample at ^2.5 mA / cm ² constant current driving ( The luminance in the 0 ° direction was measured, and the chromaticity region plotted on the 1931 CIE coordinate system was evaluated using the color coordinates CCx and CCy according to the following criteria.

<Blue light>
(Ccx) (ccy)
◎ 0.12 or more and 0.14 or less 0.05 or more and less than 0.10 ○ 0.14 or more and 0.15 or less 0.10 or more and less than 0.15 △ 0.12 or more and 0.15 or less 0.15 or more and 0.20 Less than × 0.10 or more and 0.16 or less 0.20 or more <yellow light>
(Ccx) (ccy)
◎ 0.45 or more and 0.50 or less 0.50 or more and 0.55 or less ○ 0.40 or more and less than 0.45 0.45 or more and less than 0.50 △ 0.35 or more and less than 0.40 0.40 or more and 0.45 Less than 0.30 or more but less than 0.35 0.40 or less [3] Viewing angle dependency Under the environment of 23 ° C. and 55% RH, using a spectral radiance meter CS-1000 (manufactured by Konica Minolta Sensing), The maximum distance of fluctuation of x and y values on the 1931 CIE coordinate system, with the luminance measured from the front (assuming 0 °) and the luminance measured from the 60 ° direction of each sample when driving at a constant current of ^2.5 mA / cm ^2. (Chromaticity variation) was calculated according to the following formula, and the results were ranked into ◎ to × according to the following criteria.

Chromaticity variation (ΔExy) = (Δx ² + Δy ² ) ^1/2
◎ Less than 0.05 ○ 0.05 or more but less than 0.10 Δ 0.10 or more but less than 0.20 × 0.20 or more Tables 1 and 2 show the configurations and evaluation results of the organic EL elements 101 to 107.

  From Tables 1 and 2, the organic EL elements 104 to 107 of the present invention are superior in current efficiency, front chromaticity, and viewing angle dependency to the comparative example even when the layer thickness varies. I understand.

Example 2
[Production of Organic EL Element 201]
In the production of the organic EL element 104 of Example 1, the organic EL element 201 was produced in the same manner except that the light scattering layer 2 and the smooth layer 3 described below were formed between the transparent substrate and the transparent first electrode.

(Formation of light scattering layer 2)
The solid content ratio of TiO ₂ particles having a refractive index of 2.4 and an average particle diameter of 0.25 μm (JR600A manufactured by Teika Co., Ltd.) and a resin solution (ED230AL (organic / inorganic hybrid resin) manufactured by APM) is 20% by volume / 80%. The volume percentage was adjusted so that the solid content concentration in propylene glycol monomethyl ether (PGME) was 15% by mass.

  To the solid content (effective mass component), 0.4% by mass of an additive (Disperbyk-2096 manufactured by Big Chemie Japan Co., Ltd.) was added and the formulation was designed at a ratio of 10 ml.

Specifically, the the TiO ₂ particles and a solvent and additives were mixed with 10% by weight ratio with respect to TiO ₂ particles, while cooling at room temperature (25 ° C.), an ultrasonic dispersing machine (manufactured by SMT Co. UH- 50) was added for 10 minutes under the standard conditions of the microchip step (MS-3 3 mmφ manufactured by SMT) to prepare a dispersion of TiO ₂ .

Next, while stirring the TiO ₂ dispersion at 100 rpm, the resin solution is mixed and added little by little. After the addition is completed, the stirring speed is increased to 500 rpm and mixing is performed for 10 minutes, and then a hydrophobic PVDF 0.45 μm filter (manufactured by Whatman) ) To obtain the desired light scattering layer coating solution.

  After coating the coating solution on the gas barrier layer of the substrate by an ink jet coating method, it is simply dried (80 ° C., 2 minutes), and further under the output conditions with a substrate temperature of less than 80 ° C. by wavelength control IR described later. A drying process was performed for 5 minutes.

  Next, the curing reaction was accelerated under the following modification treatment conditions to obtain a light scattering layer 2 having a layer thickness of 300 nm. In this way, a light scattering layer 2 having a refractive index n of 1.66 was produced.

<Reforming treatment conditions>
Excimer lamp light intensity: 130 mW / cm ² (172 nm)
Distance between sample and light source: 1mm
Stage heating temperature: 70 ° C
Oxygen concentration in the irradiation device: 20.0%
Excimer lamp irradiation time: 5 seconds (formation of smooth layer 3)
Next, as a coating solution for a smooth layer, a high refractive index UV curable resin (manufactured by Toyo Ink Co., Ltd., Rio Duras TYT82-01, nanosol particles: TiO ₂ ), propylene glycol monomethyl ether (PGME) and 2-methyl The formulation was designed at a ratio of 10 ml so that the solid content concentration in an organic solvent having a solvent ratio of -2,4-pentanediol (PD) of 90 mass% / 10 mass% was 12 mass%.

  Specifically, the high refractive index UV curable resin and the solvent are mixed, mixed at 500 rpm for 1 minute, filtered through a hydrophobic PVDF 0.2 μm filter (manufactured by Whatman), and applied for a desired smooth layer. A liquid was obtained.

  After applying the above coating solution on the scattering layer by the inkjet coating method, simple drying (80 ° C., 2 minutes), and further performing a drying process for 5 minutes under an output condition with a substrate temperature of less than 80 ° C. by wavelength control IR. did.

  The drying process was performed by attaching two quartz glass plates that absorb infrared rays having a wavelength of 3.5 μm or more to an IR irradiation device (ultimate heater / carbon, manufactured by Meidyo Kogyo Co., Ltd.) using a wavelength-controlled infrared heater. Flowing cooling air between the plates).

  At this time, the cooling air was set at 200 L / min, and the tube surface quartz glass temperature was suppressed to less than 120 ° C. The substrate temperature was measured by placing K thermocouples on the upper and lower surfaces of the substrate and 5 mm from the upper surface of the substrate and connecting them to NR2000 (manufactured by Keyence Corporation).

  Next, the curing reaction was promoted under the following modification treatment conditions, the smooth layer 3 having a layer thickness of 500 nm was formed, and a light extraction layer having a two-layer structure of the light scattering layer 2 and the smooth layer 3 was produced.

<Reforming treatment conditions>
Excimer lamp light intensity: 130 mW / cm ² (172 nm)
Distance between sample and light source: 1mm
Stage heating temperature: 70 ° C
Oxygen concentration in the irradiation device: 20.0% (under air)
Excimer lamp irradiation time: 0.5 seconds [Production of organic EL element 202]
In the production of the organic EL element 105 of Example 1, an organic EL element 202 was produced in the same manner as in the organic EL element 201 except that the light scattering layer 2 and the smooth layer 3 were formed.

[Production of Organic EL Element 203]
In the production of the organic EL element 106 of Example 1, an organic EL element 203 was produced in the same manner as in the organic EL element 201 except that the light scattering layer 2 and the smooth layer 3 were formed.

[Production of Organic EL Element 204]
In the production of the organic EL element 107 of Example 1, the organic EL element 204 was produced in the same manner as in the organic EL element 201 except that the light scattering layer 2 and the smooth layer 3 were formed.

  Using the produced organic EL elements 201 to 204, the current efficiency (cd / A), the front luminance and the viewing angle dependency were evaluated in the same manner as in Example 1, and the results are shown in Tables 4 and 5. The current efficiency (cd / A) is shown as a relative value with the organic EL element 101 produced in Example 1 as 100.

  The organic EL elements 201 to 204 of the present invention in which the second light scattering layer and the smooth layer are formed between the transparent substrate and the transparent first electrode are further excellent in current efficiency, front chromaticity, and viewing angle dependency. I understand that. It can also be seen that excellent characteristics can be maintained even when the layer thickness varies.

Example 3
[Production of Organic EL Element 301]
As an organic EL element of a comparative example, transparent substrate / transparent first electrode / first light emitting unit / transparent intermediate electrode 1 / second light emitting unit / transparent intermediate electrode 2 / third light emitting unit / second electrode / (sealed) An element was fabricated with the configuration.

<Transparent substrate>
In the same manner as in Example 1, a polysilazane-containing coating solution was applied on a polyester film, then subjected to a modification treatment by irradiation with vacuum ultraviolet rays to provide a gas barrier layer, and a transparent flexible substrate was produced.

<Formation of transparent first electrode>
On the gas barrier layer, ITO (Indium Tin Oxide: ITO) having a thickness of 150 nm was formed by sputtering and patterned by photolithography to form a transparent first electrode. The pattern was such that the light emission area was 50 mm square.

<Formation of first light emitting unit>
(Formation of hole injection layer 1)
As a hole injection material, the heating boat containing the compound represented by the structural formula HI-1 is energized and heated, and the heating boat containing the compound represented by the structural formula HI-2 is energized and heated to be transparent. A hole injection layer 1 was formed on the first electrode. At this time, by adjusting energization to each heating boat, the vapor deposition rates of Compound HI-1 and Compound HI-2 were made the same at 0.1 to 0.2 nm / second, and the film thickness was 15 nm.

(Formation of hole transport layer 1)
Next, the hole-transporting layer 1 was formed on the hole-injecting layer 1 by heating the heating boat containing the compound represented by the structural formula HT-1 as a hole-transporting material. At this time, after the pressure was reduced to a vacuum degree of 1 × 10 ⁻⁴ Pa using a commercially available vacuum deposition apparatus, the deposition rate was 0.1 to 0.2 nm / second and the film thickness was 50 nm.

(Formation of the light emitting layer 1)
Next, the heating boat containing the host compound H-1 and the heating boat containing the phosphorescent light emitting dopant A-3 (blue light emitting dopant: expressed as B in the table) were energized independently to each other, and the host compound H- 1 and a phosphorescent layer containing phosphorescent dopant A-3 were formed on the hole transport layer. At this time, the energization of the heating boat was adjusted so that the deposition rate was host compound H-1: phosphorescent dopant A-3 = 100: 6. The layer thickness was 30 nm.

(Formation of electron transport layer 1)
Thereafter, a heating boat containing the compound represented by the structural formula ET-1 as an electron transporting material and a heating boat containing potassium fluoride were energized independently to each other, and electrons containing ET-1 and potassium fluoride. The transport layer 1 was formed on the light emitting layer 1. At this time, the energization of the heating boat was adjusted so that the deposition rate was ET-1: potassium fluoride = 75: 25. The layer thickness was 30 nm.

(Formation of electron injection layer 1)
Next, a heating boat containing potassium fluoride as an electron injection material was energized and heated to form an electron injection layer 1 made of potassium fluoride on the electron transport layer 1. At this time, the deposition rate was 0.01 to 0.02 nm / second, and the layer thickness was 1.5 nm.

<Formation of transparent intermediate electrode 1>
On the first light emitting unit, aluminum (Al) and silver (Ag) were placed in a resistance heating boat made of tungsten, respectively, and mounted in the first vacuum chamber. After depressurizing the vacuum chamber to 4 × 10 ⁻⁴ Pa, each of the resistance heating boats is independently energized and heated, and the transparent intermediate electrode layer 1 having a thickness ratio of aluminum (Al) 1 nm and silver (Ag) 12 nm is formed. The transparent intermediate electrode 1 was formed by co-evaporation and patterning by photolithography. The pattern was such that the light emission area was 50 mm square.

<Formation of second light emitting unit>
In the formation of the first light emitting unit, the second light emitting unit was formed in the same manner except that the hole transport layer 2, the light emitting layer 2 and the electron transport layer 2 were formed as follows.

(Formation of hole transport layer 2)
In the formation of the first light emitting unit, the hole transport layer 2 was formed in the same manner except that the layer thickness was changed to 30 nm.

(Formation of the light emitting layer 2)
The heating boat containing the host compound H-1 and the heating boat containing the phosphorescent light emitting dopant A-2 (red light emitting dopant: indicated as R in the table) were independently energized, respectively, and the host material H-1, A light emitting layer containing A-2 was formed by co-evaporation on the hole injection layer. At this time, the energization of the heating boat was adjusted so that the deposition rate was host compound H-1: phosphorescent light emitting dopant A-2 = 100: 4. The layer thickness was 30 nm.

(Formation of electron transport layer 2)
In the formation of the first light emitting unit, the electron transport layer 2 was formed in the same manner except that the layer thickness was changed to 40 nm.

<Formation of transparent intermediate electrode 2>
On the first light emitting unit, aluminum (Al) and silver (Ag) were placed in a resistance heating boat made of tungsten, respectively, and mounted in the first vacuum chamber. After depressurizing the vacuum chamber to 4 × 10 ⁻⁴ Pa, each of the resistance heating boats is independently energized and heated, and the transparent intermediate electrode layer 1 having a thickness ratio of aluminum (Al) 1 nm and silver (Ag) 12 nm is formed. The transparent intermediate electrode 1 was formed by co-evaporation and patterning by photolithography. The pattern was such that the light emission area was 50 mm square.

<Formation of third light emitting unit>
In the formation of the first light emitting unit, a third light emitting unit was formed in the same manner except that the hole injection layer 3, the hole transport layer 3 and the light emitting layer 3 were produced by the following procedure.

(Formation of hole injection layer 3)
A hole injection layer 3 was formed in the same manner except that the thickness of the hole injection layer 1 was 10 nm.

(Formation of hole transport layer 3)
In the formation of the first light emitting unit, the hole transport layer 3 was formed in the same manner except that the layer thickness was changed to 30 nm.

(Formation of the light emitting layer 3)
The heating boat containing the host compound H-1 and the heating boat containing the phosphorescent light emitting dopant A-1 (green light emitting dopant: indicated as G in the table) were energized independently, and the host material H-1, A light emitting layer containing A-1 was formed by co-evaporation on the hole injection layer. At this time, the energization of the heating boat was adjusted so that the vapor deposition rate was host compound H-1: phosphorescent dopant A-1 = 100: 4. The layer thickness was 30 nm.

<Formation of second electrode>
On the electron injection layer of the third light emitting unit formed as described above, except for the portion that becomes the extraction electrode of the transparent first electrode and the transparent intermediate electrode, the second is applied under a vacuum of 5 × 10 ⁻⁴ Pa. Aluminum (Al) was used as an electrode forming material, and a mask pattern was formed so as to have a light emitting area of 50 mm square using an evaporation method so as to have an extraction electrode, and a second electrode having a thickness of 100 nm was laminated.

  Next, the organic EL element was sealed in the same manner as in Example 1 to produce an organic EL element 301.

[Production of Organic EL Element 302]
In the production of the organic EL element 301, the organic EL element 302 was produced by forming the third light emitting unit according to the above procedure except that the thickness of the hole transport layer of the third light emitting unit was 80 nm.

[Production of Organic EL Element 303]
In the production of the organic EL element 301, an organic EL element 303 having the configuration shown in FIG. 4 was produced in the same manner except that the first light emitting unit and the second light emitting unit were formed by the following procedure.

<Formation of first light emitting unit>
The hole injection layer, the hole transport layer, the light emitting layer, and the electron injection layer were formed in the same manner as the fabrication of the organic EL element 301.

(Electron transport / light scattering layer 1)
On the light emitting layer, the electron transport / light scattering layer 1 was formed by the following procedure.

  A coating solution for the electron transport / light scattering layer 1 was prepared as described below, and coated with a spin coater under conditions of 1500 rpm and 30 seconds. Furthermore, the substrate was heated at a substrate surface temperature of 120 ° C. for 30 minutes to provide the electron transport / light scattering layer 2. When the coating was performed under the same conditions on a separately prepared substrate and measured, the film thickness was 40 nm.

(Coating liquid for electron transport / light scattering layer 1)
2,2,3,3-tetrafluoro-1-propanol 100 g
ET-1 0.75g
Anisotropic fine particle dispersion (FS-10D manufactured by Ishihara Sangyo Co., Ltd.) 8% by volume
FS-10D manufactured by Ishihara Sangyo Co., Ltd .: SnO ₂ , acicular (anisotropic), minor axis median diameter 20 nm, aspect ratio 10-200
<Formation of second light emitting unit>
The hole injection layer, the hole transport layer, the light emitting layer, and the electron injection layer were formed in the same manner as the fabrication of the organic EL element 301.

(Electron transport / light scattering layer 1-2)
An electron transport / light scattering layer 1-2 was formed on the light emitting layer by the following procedure.

  The coating solution for the electron transport / light scattering layer 1 was prepared as described above, and was applied with a spin coater under conditions of 1500 rpm and 30 seconds. Further, the electron transport / light scattering layer 1 was provided by heating at a substrate surface temperature of 120 ° C. for 30 minutes. When the coating was performed under the same conditions on a separately prepared substrate and measured, the film thickness was 40 nm.

[Production of Organic EL Element 304]
In the production of the organic EL element 303, the third light emitting unit was formed by the above procedure except that the thickness of the hole transport layer of the third light emitting unit was set to 80 nm, and the organic EL element 304 was produced.

  Using the produced organic EL elements 301 to 304, the current efficiency (cd / A), the front luminance, and the viewing angle dependency were evaluated in the same manner as in Example 1, and the results are shown in Tables 5 and 6.

  It can be seen that the organic EL elements 303 and 304 including the three-layer light emitting unit of the present invention are superior in current efficiency, front chromaticity, and viewing angle dependency with respect to the comparative example.

Example 4
[Production of Organic EL Element 401]
As an organic EL element of a comparative example, transparent substrate / transparent first electrode / first light emitting unit / transparent intermediate electrode 1 / second light emitting unit / transparent intermediate electrode 2 / third light emitting unit / second electrode / (sealed) The organic EL element 401 was produced with the configuration.

<Transparent substrate>
In the same manner as in Example 1, a polysilazane-containing coating solution was applied on a polyester film, then subjected to a modification treatment by irradiation with vacuum ultraviolet rays to provide a gas barrier layer, and a transparent flexible substrate was produced.

<Formation of transparent first electrode>
A transparent substrate with a gas barrier layer was set in a substrate holder, the compound ET-1 was placed in a resistance heating boat made of tantalum, and these substrate holder and heating boat were attached to a first vacuum chamber of a vacuum deposition apparatus.

In this state, first, the first vacuum chamber was depressurized to 4 × 10 ⁻⁴ Pa, and then heated by energizing the heating boat containing the compound represented by the structural formula ET-1, and the deposition rate was 0.1 nm / second. A base layer made of ET-1 having a layer thickness of 25 nm was provided on the transparent substrate.

Next, the transparent substrate formed up to the base layer was transferred to the second vacuum chamber while being vacuumed, and silver (Ag) was placed in a resistance heating boat made of tungsten, and attached in the vacuum chamber. Next, after depressurizing the vacuum chamber to 4 × 10 ⁻⁴ Pa, the resistance heating boat was energized and heated to form a transparent first electrode having a single layer structure made of silver by resistance heating evaporation. The layer thickness of the formed transparent first electrode made of silver (Ag) was 12 nm.

<Formation of first light emitting unit>
(Formation of hole injection layer 1)
As a hole injection material, the heating boat containing the compound represented by the structural formula HI-1 is energized and heated, and the heating boat containing the compound represented by the following structural formula HI-2 is energized and heated to be transparent. A hole injection layer 1 was formed on the first electrode. At this time, by adjusting energization to each heating boat, the vapor deposition rates of Compound HI-1 and Compound HI-2 were the same at 0.1 to 0.2 nm / second, and the film thickness was 10 nm.

(Formation of hole transport layer 1)
Next, the hole-transporting layer 1 was formed on the hole-injecting layer 1 by heating the heating boat containing the compound represented by the structural formula HT-1 as a hole-transporting material. At this time, after the pressure was reduced to a vacuum degree of 1 × 10 ⁻⁴ Pa using a commercially available vacuum deposition apparatus, the deposition rate was 0.1 to 0.2 nm / second and the film thickness was 30 nm.

(Formation of the light emitting layer 1)
Next, the heating boat containing the host compound H-1 and the heating boat containing the phosphorescent emission dopant A-1 (green emission dopant: indicated as G in the table) were energized independently to each other, and the host material H-1 The light emitting layer containing A-1 was formed by co-evaporation on the hole injection layer. At this time, the energization of the heating boat was adjusted so that the vapor deposition rate was host compound H-1: phosphorescent dopant A-1 = 100: 4. The layer thickness was 30 nm.

(Formation of electron transport layer 1)
Thereafter, a heating boat containing the compound represented by the structural formula ET-1 as an electron transporting material and a heating boat containing potassium fluoride were energized independently to each other, and electrons containing ET-1 and potassium fluoride. The transport layer 1 was formed on the light emitting layer 1. At this time, the energization of the heating boat was adjusted so that the deposition rate was ET-1: potassium fluoride = 75: 25. The layer thickness was 20 nm.

(Formation of electron injection layer 1)
Next, a heating boat containing potassium fluoride as an electron injection material was energized and heated to form an electron injection layer 1 made of potassium fluoride on the electron transport layer 1. At this time, the deposition rate was 0.01 to 0.02 nm / second, and the layer thickness was 1.5 nm.

<Formation of transparent intermediate electrode 1>
On the first light emitting unit, aluminum (Al) and silver (Ag) were placed in a resistance heating boat made of tungsten, respectively, and mounted in the first vacuum chamber. After depressurizing the vacuum chamber to 4 × 10 ⁻⁴ Pa, each of the resistance heating boats is independently energized and heated, and the transparent intermediate electrode layer 1 having a thickness ratio of aluminum (Al) 1 nm and silver (Ag) 12 nm is formed. The transparent intermediate electrode 1 was formed by co-evaporation and patterning by photolithography. The pattern was such that the light emission area was 50 mm square.

<Formation of second light emitting unit>
Similarly to the formation of the first light emitting unit, the second light emitting unit was formed in the same manner except that the formation of the hole transport layer 2, the light emitting layer 2, and the electron transport layer 2 was as follows.

(Formation of hole transport layer 2)
In the formation of the first light emitting unit, the hole transport layer 2 was formed in the same manner except that the layer thickness was changed to 40 nm.

(Formation of the light emitting layer 2)
Next, the heating boat containing the host compound H-1 and the heating boat containing the phosphorescent light emitting dopant A-3 (blue light emitting dopant: expressed as B in the table) were energized independently to each other, and the host compound H- 1 and a phosphorescent layer containing phosphorescent dopant A-3 were formed on the hole transport layer. At this time, the energization of the heating boat was adjusted so that the deposition rate was host compound H-1: phosphorescent dopant A-3 = 100: 6. The layer thickness was 30 nm.

(Formation of electron transport layer 2)
In the formation of the first light emitting unit, the electron transport layer 2 was formed in the same manner except that the layer thickness was changed to 30 nm.

<Formation of transparent intermediate electrode 2>
On the first light emitting unit, aluminum (Al) and silver (Ag) were placed in a resistance heating boat made of tungsten, respectively, and mounted in the first vacuum chamber. After depressurizing the vacuum chamber to 4 × 10 ⁻⁴ Pa, each of the resistance heating boats is independently energized and heated, and the transparent intermediate electrode layer 1 having a thickness ratio of aluminum (Al) 1 nm and silver (Ag) 12 nm is formed. The transparent intermediate electrode 1 was formed by co-evaporation and patterning by photolithography. The pattern was such that the light emission area was 50 mm square.

<Formation of third light emitting unit>
In the formation of the first light emitting unit, a third light emitting unit was formed in the same manner except that the hole injection layer 3, the hole transport layer 3 and the light emitting layer 3 were produced by the following procedure.

(Formation of hole injection layer 3)
A hole injection layer 3 was formed in the same manner except that the thickness of the hole injection layer 1 was changed to 15 nm.

(Formation of hole transport layer 3)
In the formation of the first light emitting unit, the hole transport layer 3 was formed in the same manner except that the layer thickness was changed to 50 nm.

(Formation of the light emitting layer 3)
Then, the heating boat containing the host compound H-1 and the heating boat containing the phosphorescent dopant A-2 (red light emitting dopant: indicated as R in the table) were energized independently, and the host material H- 1, A light-emitting layer containing A-2 was formed by co-evaporation on the hole injection layer. At this time, the energization of the heating boat was adjusted so that the deposition rate was host compound H-1: phosphorescent light emitting dopant A-2 = 100: 4. The layer thickness was 30 nm.

<Formation of second electrode>
On the electron injection layer of the third light emitting unit formed as described above, except for the portion that becomes the extraction electrode of the transparent first electrode and the transparent intermediate electrode, the second is applied under a vacuum of 5 × 10 ⁻⁴ Pa. Aluminum (Al) was used as an electrode forming material, and a mask pattern was formed so as to have a light emitting area of 50 mm square using an evaporation method so as to have an extraction electrode, and a second electrode having a thickness of 100 nm was laminated.

  Next, the organic EL element was sealed in the same manner as in Example 1 to produce an organic EL element 401.

[Production of Organic EL Element 402]
In the production of the organic EL element 401, the organic EL element 402 was produced in the same manner except that the thickness of the hole transport layer of the third light emitting unit was changed to 60 nm.

[Production of Organic EL Element 403]
In the production of the organic EL element 401, similarly to the production of the organic EL element 201 of Example 2, the light scattering layer 2 and the smooth layer 3 are formed between the transparent substrate and the transparent first electrode, and the first light emitting unit and An organic EL element 403 having the configuration shown in FIG. 4 was produced in the same manner except that the second light emitting unit was formed by the following procedure.

<Formation of first light emitting unit>
The hole injection layer, the hole transport layer, the light emitting layer, and the electron injection layer were formed in the same manner as the organic EL element 401 was manufactured.

(Electron transport / light scattering layer 1)
On the light emitting layer, the electron transport / light scattering layer 1 was formed by the following procedure.

  A coating solution for the electron transport / light scattering layer 1 was prepared as described below, and coated with a spin coater under conditions of 1500 rpm and 30 seconds. Furthermore, the substrate was heated at a substrate surface temperature of 120 ° C. for 30 minutes to provide the electron transport / light scattering layer 2. The film thickness was 20 nm when it apply | coated and measured on the conditions with the board | substrate prepared separately.

(Coating liquid for electron transport / light scattering layer 1)
2,2,3,3-tetrafluoro-1-propanol 100 g
ET-1 0.75g
Anisotropic fine particle dispersion (FS-10D manufactured by Ishihara Sangyo Co., Ltd.) 8% by volume
FS-10D manufactured by Ishihara Sangyo Co., Ltd .: SnO ₂ , acicular (anisotropic), minor axis median diameter 20 nm, aspect ratio 10-200
<Formation of second light emitting unit>
The hole injection layer, the hole transport layer, the light emitting layer, and the electron injection layer were formed in the same manner as the organic EL element 401 was manufactured.

(Electron transport / light scattering layer 1-2)
An electron transport / light scattering layer 1-2 was formed on the light emitting layer by the following procedure.

  The coating solution for the electron transport / light scattering layer 1 was prepared as described above, and was applied with a spin coater under conditions of 1500 rpm and 30 seconds. Furthermore, it heated at the substrate surface temperature of 120 degreeC for 30 minutes, and provided the electron transport / light-scattering layer 1-2. The film thickness was 30 nm when it applied and measured on the conditions prepared with the board | substrate prepared separately.

[Production of Organic EL Element 404]
In the production of the organic EL element 403, an organic EL element 404 was produced in the same manner except that the thickness of the hole transport layer of the third light emitting unit was changed to 60 nm.

  Using the produced organic EL elements 401 to 404, the current efficiency (cd / A), the front luminance, and the viewing angle dependency were evaluated in the same manner as in Example 1, and the results are shown in Tables 7 and 8.

  The organic EL elements 403 and 404 of the present invention, in which the second light scattering layer 2 and the smooth layer 3 are formed between the transparent substrate and the transparent first electrode, are further improved in current efficiency, front chromaticity, and viewing angle dependency. It turns out that it is excellent. It can also be seen that excellent characteristics can be maintained even when the layer thickness varies.

DESCRIPTION OF SYMBOLS 100 Organic EL element 101 Transparent 1st electrode 102 2nd electrode 103-1 1st light emission unit 103-1a Hole injection layer 103-1b Hole transport layer 103-1c Light emission layer 103-1d Electron transport layer 103-1e Electron injection Layer 104-1 Transparent intermediate electrode 104-2 Transparent intermediate electrode 103-2 Second light emitting unit 103-2a Hole injection layer 103-2b Hole transport layer 103-2c Light emission layer 103-2d Electron transport layer 103-2e Electron injection Layer 103-3 Third light emitting unit 105 Light scattering layer 1
106 Smooth layer 107 Adhesive (not shown)
108 Transparent substrate 109 Sealing member 110 Light scattering layer 2
111 Smooth layer 3

Claims (3)

A laminated organic electroluminescent element having a transparent substrate, a transparent first electrode, a plurality of light emitting units having different maximum light emission maximum wavelengths, and a second electrode in this order,
A laminated type comprising a transparent intermediate electrode between the plurality of light emitting units, and a light scattering layer between the light emitting unit adjacent to the transparent intermediate electrode and on the light extraction side and the transparent intermediate electrode. Organic electroluminescence element.   The light scattering layer is a functional layer of the light emitting unit adjacent to the transparent intermediate electrode and located on the light extraction side among the light emitting units facing each other with the transparent intermediate electrode interposed therebetween. The laminated organic electroluminescence element described.   The stacked organic electroluminescent device according to claim 1, further comprising a second light scattering layer between the transparent substrate and the transparent first electrode.

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