JP2010147179A - Organic electroluminescent element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic electroluminescent element exhibiting less change in hue in response to a change in a voltage applied to an electrode, and having high durability and excellent luminous performance. <P>SOLUTION: The organic electroluminescent element includes: an anode; a cathode; a multilayer luminous part arranged between the anode and the cathode and including a plurality of stacked luminous layers, each of which emits light with a peak wavelength different from one another and which are arranged such that a luminous layer emitting light with a longer peak wavelength is positioned closer to the anode; a support substrate on which a laminate including the anode, the cathode and the multilayer luminous part are mounted; a sealing substrate facing the support substrate and sandwiching the laminate; and a heat dissipation layer arranged on at least one principal surface of the support substrate or at least one principal surface of the sealing substrate, and having a thermal emissivity of 0.70 or more. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an organic electroluminescence element (hereinafter sometimes referred to as an organic EL element) planar light source, an illumination device, and a display device.

  The organic EL element mainly includes an anode, a cathode, and a light emitting unit sandwiched between the pair of electrodes. The light emitting portion is formed of an organic compound, and the light emitting portion emits light when a voltage is applied between the electrodes. For example, an organic EL element that includes a light-emitting portion that includes only a white light-emitting layer in which a plurality of types of pigments are dispersed and emits white light is disclosed (for example, see Patent Document 1).

  When electric power is supplied and the organic EL element emits light, part of the supplied electric power is converted into thermal energy by Joule heat or the like, and the organic EL element generates heat. The organic EL element tends to have a shorter lifetime as the temperature during driving increases, and the high temperature during driving is one of the factors that cause deterioration in light emission characteristics such as luminance and deterioration of the organic EL element itself. It is considered. Lighting devices that are expected to be put into practical use as devices equipped with organic EL elements, in particular, need to drive the organic EL elements with high brightness, and therefore generate a large amount of heat. Thus, it is an important issue to determine whether or not to discharge outside the apparatus. For this reason, various measures for dissipating heat generated in the organic EL element to the outside of the element have been studied. As a technique for improving heat dissipation, it has been proposed to employ a material having high thermal conductivity for some members (for example, Patent Document 2). In addition, it has been proposed to provide a heat dissipation film in a part of the internal structure of the organic EL element (for example, Patent Document 3).

Japanese Patent Application Laid-Open No. 07-220871 JP 2004-186045 A JP 2006-244847 A

  In the organic EL element, it is required to further improve the light emission performance. It has been pointed out that the organic EL element of the prior art has a large change in color with respect to a change in applied voltage. For example, when an organic EL element is used in an illumination device, the color of illumination changes according to the brightness. For example, when an organic EL element is used in a backlight of a liquid crystal display device, an image that is expressed Since the color of information changes according to luminance, there arises a problem that display quality is deteriorated. For this reason, there is a demand for an organic EL element that has little change in color with respect to a change in applied voltage. In addition to such a problem that the color change becomes large, improvement for increasing the light emission efficiency is always required for the development of organic EL elements. Furthermore, there is a strong demand for improving the durability of the organic EL element that can withstand use at high brightness for a long time. As one means for improving durability, it is required to efficiently release the heat generated by the organic EL element to the outside of the apparatus.

  An object of the present invention is to provide an organic EL element that has little change in color with respect to a change in voltage applied to an electrode, high durability, and excellent light emitting performance.

In order to solve the above problems, the present invention provides an organic EL element having the following configuration and an apparatus for mounting the organic EL element.
[1] an anode,
A cathode,
Between the anode and the cathode, a multi-layer light emitting part formed by laminating a plurality of light emitting layers disposed closer to the anode as the light emitting layer having a longer peak wavelength of emitted light;
A support substrate on which a laminate including the anode, the cathode, and the multilayer light emitting unit is mounted;
A sealing substrate disposed opposite to the support substrate and sandwiching the laminate together with the support substrate;
A heat dissipating layer disposed on at least one main surface of the support substrate or at least one main surface of the sealing substrate and having a thermal emissivity of 0.70 or more;
An organic electroluminescence device comprising:
[2] The organic electroluminescence device according to [1], wherein the multi-layer light emitting section includes three layers of a light emitting layer that emits red light, a light emitting layer that emits green light, and a light emitting layer that emits blue light. Luminescence element.
[3] The organic electroluminescence device according to [1] or [2], wherein the light emitting layer is a layer containing a light emitting polymer organic compound.
[4] When the voltage applied between the anode and the cathode is changed, the width of the change between the coordinate value x and the coordinate value y in the chromaticity coordinates of the light extracted outside is 0.05 respectively. The organic electroluminescence device according to any one of [1] to [3], which is the following.
[5] The organic electroluminescent element according to any one of [1] to [4], wherein the heat emissivity of the heat dissipation layer is 0.85 or more.
[6] The organic electroluminescent element according to any one of [1] to [5], wherein the heat dissipation layer has a thermal conductivity of 1 W / mK or more.
[7] The organic electroluminescent element according to any one of [1] to [6], wherein the heat dissipation layer has a thermal conductivity of 200 W / mK or more.
[8] The organic electroluminescent element according to any one of [1] to [7], wherein the heat dissipation layer includes a black material.
[9] The organic electroluminescent element according to the above [8], wherein the heat dissipation layer has a laminated structure including a high thermal conductivity layer and a black material layer.
[10] The high thermal conductivity layer is formed of aluminum, copper, silver, a ceramic material, and an inorganic material selected from the group consisting of two or more alloys selected from these, or a high thermal conductivity resin. The organic electroluminescent element according to [9] above.
[11] The organic electroluminescence element according to any one of [1] to [10], wherein the support substrate is a glass substrate, and the heat dissipation layer is provided on at least one main surface of the glass substrate. .
[12] The organic electroluminescence element according to [11], wherein the heat dissipation layer is provided on a main surface of the glass substrate opposite to a main surface on which the stacked body is mounted.
[13] The organic electroluminescence element according to [13], wherein the heat dissipation layer is provided on both main surfaces of the glass substrate.
[14] The heat dissipation layer is provided on the main surface of the glass substrate opposite to the main surface on which the laminate is mounted, and the high thermal conductivity layer is provided on the main surface of the glass substrate on the laminate side. The organic electroluminescence device according to [11] above.
[15] The organic electroluminescence according to any one of [1] to [14], wherein the sealing substrate is a glass substrate, and the heat dissipation layer is provided on at least one main surface of the glass substrate. element.
[16] A planar light source comprising the organic electroluminescence device according to any one of [1] to [15].
[17] An illumination device comprising the organic electroluminescence element according to any one of [1] to [15].
[18] A display device comprising the organic electroluminescence element according to any one of [1] to [15].

  ADVANTAGE OF THE INVENTION According to this invention, the organic EL element which has little change of color with respect to the change of the voltage applied to an electrode, is excellent in heat dissipation, and is durable, and an apparatus which mounted this are provided.

  Embodiments of the present invention will be described below with reference to the drawings. For ease of understanding, the scale of each member in the drawing may be different from the actual one. The present invention is not limited to the following description, and can be appropriately changed without departing from the gist of the present invention. In the organic EL device, there are members such as electrode lead wires. However, in the explanation of the present invention, these members are omitted because they are not required directly. For convenience of explanation of the layer structure and the like, in the example shown below, the explanation will be made with the figure in which the substrate is arranged below. However, the organic EL element of the present invention and the organic EL device equipped with the element are not necessarily manufactured or manufactured in this arrangement. It is not used. In the following description, one of the substrate in the thickness direction may be referred to as “up” or “up”, and the other in the thickness direction may be referred to as “down” or “down”.

1. Organic EL Device of the Present Invention The organic EL device of the present invention includes an anode, a cathode, a multilayer light emitting unit, a support substrate, a sealing substrate, and a heat dissipation layer. The multi-layer light emitting part is disposed between the anode and the cathode, and is formed by laminating a plurality of light emitting layers that emit light having different peak wavelengths, and each light emitting layer has a longer peak wavelength by the front anode. It is arranged at a close position. In addition, a laminated body including an anode, a cathode, and a multilayer light emitting part (hereinafter, “a laminated body including an anode, a cathode, and a multilayer light emitting part” may be simply referred to as “light emitting function part”) is mounted on the support substrate. ing. The sealing substrate is disposed to face the support substrate, and sandwiches the light emitting function part together with the support substrate. The heat dissipation layer is provided on at least one main surface of the support substrate or at least one main surface of the sealing substrate, and the heat emissivity of the heat dissipation layer is 0.70 or more.

  The organic EL device of the present invention has a multi-layer light emitting portion including a plurality of light emitting layers, and the light emitting layer having a longer peak wavelength is disposed closer to the anode, so that the voltage applied to the electrode can be changed. Thus, an organic EL element with little color change and high luminous efficiency can be realized. Furthermore, since the heat dissipation layer having a thermal emissivity of 0.70 or more is provided, the heat dissipation is excellent and the durability is improved. Thereby, it is possible to extend the life of the element. Therefore, the organic EL element of the present invention is excellent in light emission performance in terms of electrical characteristics and durability, and can be suitably used for lighting devices, planar light sources, display device backlights, and the like.

<First Embodiment of Organic EL Element>
A first embodiment of an organic EL element and its modification will be described with reference to FIG. FIG. 1 is a cross-sectional view showing a first embodiment of an organic EL element.

<1. Substrate>
As a substrate constituting the organic EL element 1, there are a support substrate 10 and a sealing substrate 30. The support substrate 10 has the light emitting function unit 20 mounted on one main surface thereof. The sealing substrate 30 covers the light emitting functional unit 20 on the support substrate 10 and seals the element. As shown in FIG. 1, the sealing substrate 30 and the support substrate 10 are bonded together by an adhesive portion 40.

  The support substrate 10 is a planar substrate having a region where the light emitting function unit 20 can be mounted. In the present specification, two main planes of a flat plate or thin film (film) substrate are referred to as main surfaces. The support substrate 10 may be a rigid substrate or a flexible substrate. The material constituting the support substrate 10 is preferably a material that is not easily denatured when the light emitting function part 20 is formed. Examples thereof include glass, plastic, polymer film, silicon plate, metal plate, and a laminate of these. It is done. Further, a plastic, a polymer film or the like that has been subjected to a low water permeability treatment may be used. Moreover, the support substrate 10 can use a commercially available thing, or can also manufacture it by a well-known method.

  The shape of the sealing substrate 30 is not particularly limited as long as it can be bonded to the support substrate 10 to seal the light emitting function unit 20, and may be flat as shown in FIG. You may use the plate-shaped board | substrate with which the counterbore to accommodate was formed in the surface part (not shown). In the example shown in FIG. 1, a gap is formed between the sealing substrate 30 and the light emitting function unit 20. However, a filler such as a resin may be provided in the gap. The sealing substrate 30 may be a rigid substrate or a flexible substrate. The sealing substrate 30 plays a role of protecting the light emitting function unit. The same thing as the example illustrated about the said support substrate 10 may be employ | adopted.

  Examples of materials that can constitute the substrate include the materials described above, and glass is preferable from the viewpoint of ease of handling. On the other hand, glass is a material with low thermal radiation. As described in detail below, the present invention adopts a configuration excellent in heat dissipation, and can overcome the problem that heat dissipation decreases when a material having low heat radiation such as glass is used for the substrate.

<1.2. Light emitting function>
The light emitting function unit 20 includes an anode 21, a cathode 22, and a multilayer light emitting unit 23 positioned therebetween. An arbitrary layer may be further added to the light emitting function unit 20.

<A> Multi-layer Light Emitting Unit The multi-layer light-emitting unit 23 includes a plurality of light-emitting layers, and preferably includes three or more light-emitting layers. In the present embodiment shown in FIG. 1, a red light emitting layer (hereinafter sometimes referred to as a red light emitting layer) 23a, a green light emitting layer (hereinafter sometimes referred to as a green light emitting layer) 23b, and a blue color And a light emitting layer (hereinafter sometimes referred to as a blue light emitting layer) 23c are stacked in this order. Since the red light emitting layer 23a has the longest peak wavelength of the emitted light among the three light emitting layers 23a, 23b, and 23c constituting the multilayer light emitting unit 23, the red light emitting layer 23a is among the three light emitting layers 23a, 23b, and 23c. It is arranged closest to the anode 21. The green light emitting layer 23b is disposed at the center of the three light emitting layers 23a, 23b, and 23c because the peak wavelength of the emitted light is the second longest among the three light emitting layers 23a, 23b, and 23c. The blue light emitting layer 23c has the shortest peak wavelength of emitted light among the three light emitting layers 23a, 23b, and 23c, and therefore is disposed closest to the cathode 22 among the three light emitting layers 23a, 23b, and 23c. Yes. The multilayer light emitting unit 23 is preferably composed of only a plurality of light emitting layers, but a predetermined layer different from the light emitting layer may be provided between the light emitting layer and the light emitting layer.

  In this specification, the peak wavelength emitted from the light emitting layer refers to a wavelength that provides the strongest light intensity when the emitted light is viewed in the wavelength region.

  As the red light emitting layer 23a, one having a peak wavelength of emitted light of, for example, 580 nm to 660 nm, preferably 600 to 640 nm can be used. Moreover, as the green light emitting layer 23b, the peak wavelength of the emitted light may be, for example, 500 nm to 560 nm, and preferably 520 nm to 540 nm. Moreover, as the blue light emitting layer 23c, the thing whose peak wavelength of the light to light-emit is 400 nm-500 nm, for example, Preferably 420 nm-480 nm can be used. When the light emitted from each of the three light emitting layers 23a, 23b, and 23c that emit light at such a peak wavelength is superimposed, white light is generated. Therefore, the multi-layer light emitting unit 23 has a red light emitting layer 23a, a green light emitting layer 23b, The organic EL element 1 according to the first embodiment configured by the blue light emitting layer 23c emits white light.

Each of the light emitting layers 23a, 23b, and 23c is composed of an organic compound that emits fluorescence and / or phosphorescence as a main component (hereinafter sometimes referred to as a light emitting organic compound). The light-emitting organic compound can be classified into a low molecular weight type and a high molecular weight type, and a light-emitting high molecular weight organic compound can be preferably used. In addition to the light emitting organic compound, an inorganic material such as a metal complex light emitting material may be added to the light emitting layer. In the present specification, the polymer is a compound having a polystyrene-equivalent number average molecular weight of 10 ³ or more. Although there is no particular reason for specifying an upper limit for the number average molecular weight of the polymer in the present invention, the upper limit of the number average molecular weight of the polymer is usually 10 ⁸ or less in terms of polystyrene. Moreover, you may comprise a light emitting layer so that arbitrary components, such as a dopant, may be included. For example, the dopant is added for the purpose of improving the light emission efficiency or changing the light emission wavelength. Examples of the light emitting material mainly constituting each of the light emitting layers 23a, 23b, and 23c include those shown below.

  Examples of dye-based light-emitting materials include cyclopentamine derivatives, tetraphenylbutadiene derivative compounds, triphenylamine derivatives, oxadiazole derivatives, pyrazoloquinoline derivatives, distyrylbenzene derivatives, distyrylarylene derivatives, pyrrole derivatives, thiophenes. Examples of the polymer include ring compounds, pyridine ring compounds, perinone derivatives, perylene derivatives, oligothiophene derivatives, oxadiazole dimers, quinacridone derivatives, coumarin derivatives, and pyrazoline dimers.

  Metal complex light emitting materials include rare earth metals such as Tb, Eu, and Dy, Al, Zn, Be, and Ir as central metals, oxadiazole, thiadiazole, phenylpyridine, phenylbenzimidazole, quinoline structures, etc. Can be mentioned, for example, iridium complexes, metal complexes having light emission from a triplet excited state such as platinum complexes, aluminum quinolinol complexes, benzoquinolinol beryllium complexes, Benzoxazolyl zinc complex, benzothiazole zinc complex, azomethyl zinc complex, porphyrin zinc complex, europium complex and the like can be listed as polymers.

  Examples of the polymer light-emitting material include polyparaphenylene vinylene derivatives, polythiophene derivatives, polyparaphenylene derivatives, polysilane derivatives, polyacetylene derivatives, polyfluorene derivatives, and polyvinylcarbazole derivatives.

  Examples of the light emitting material constituting the red light emitting layer 23a include coumarin derivatives, thiophene ring compounds, and polymers thereof, polyparaphenylene vinylene derivatives, polythiophene derivatives, polyfluorene derivatives, etc. among the above-described light emitting materials. . Among these, polymer materials such as polyparaphenylene vinylene derivatives, polythiophene derivatives, and polyfluorene derivatives are preferable.

  Examples of the light emitting material constituting the green light emitting layer 23b include quinacridone derivatives, coumarin derivatives, thiophene ring compounds and polymers thereof, polyparaphenylene vinylene derivatives, polyfluorene derivatives, and the like among the above light emitting materials. Of these, polymer materials such as polyparaphenylene vinylene derivatives and polyfluorene derivatives are preferred.

  Examples of the material constituting the blue light emitting layer 23c include distyrylarylene derivatives and / or polymers of oxadiazole derivatives, polyvinylcarbazole derivatives, polyparaphenylene derivatives, polyfluorene derivatives, etc. Can do. Of these, polymer materials such as polyvinyl carbazole derivatives, polyparaphenylene derivatives, and polyfluorene derivatives are preferred.

  As the light emitting material constituting each light emitting layer, in addition to the above light emitting material, for example, a dopant material may be further included for the purpose of improving the light emission efficiency or changing the light emission wavelength. Examples of such dopant materials include perylene derivatives, coumarin derivatives, rubrene derivatives, quinacridone derivatives, squalium derivatives, porphyrin derivatives, styryl dyes, tetracene derivatives, pyrazolone derivatives, decacyclene, phenoxazone, and the like.

  Each of the light emitting layers 23 a, 23 b, and 23 c constituting the multilayer light emitting unit 23 is preferably thinner as the light emitting layer disposed closer to the anode 21. Specifically, the green light emitting layer 23b is preferably thicker than the red light emitting layer 23a, and the blue light emitting layer 23c is thicker than the green light emitting layer 23b. More specifically, the layer thickness of the red light emitting layer 23a is preferably 5 nm to 20 nm, and more preferably 10 nm to 15 nm. The layer thickness of the green light emitting layer 23b is preferably 10 nm to 30 nm, more preferably 15 nm to 25 nm. The layer thickness of the blue light emitting layer 23c is preferably 40 nm to 70 nm, and more preferably 50 nm to 65 nm. By setting the layer thickness of each of the light emitting layers 23a, 23b, and 23c as described above, the organic EL element 1 that emits light with high efficiency and less change in color with respect to the change in voltage applied to the electrodes. Can be realized.

  In addition, the light emitting layers 23a, 23b, and 23c constituting the multilayer light emitting unit 23 are disposed on the anode 21 side as the light emitting layer having a longer peak wavelength of the emitted light. Therefore, the layers of the light emitting layers 23a, 23b, and 23c are arranged. By setting the thickness, it is possible to realize the organic EL element 1 with little change in color and high luminous efficiency with respect to a change in voltage applied to the electrode. In addition, the highest occupied molecular orbital (abbreviated as HOMO) and the lowest unoccupied molecular orbital (abbreviated as LUMO) of a compound constituting the light emitting layer tend to be lower as the peak wavelength of the emitted light is longer. It is in. In the present embodiment, each light emitting layer 23a, 23b, 23c is arranged closer to the anode 21 side as the light emitting layer having a longer peak wavelength of emitted light. As a result, the light emitting layer composed of a compound having low HOMO and LUMO. As a result, it is arranged closer to the anode 21 side. As described above, the light emitting layers 23a, 23b, and 23c are arranged so that the HOMO and the LUMO sequentially increase from the anode 21 side toward the cathode 22, so that the holes injected from the anode 21 side and the cathode 22 respectively It can be presumed that electrons can be efficiently transported, whereby an organic EL element having a high luminous efficiency can be realized with little change in color with respect to a change in voltage applied to the electrode.

As described above, in the organic EL element 1 having a configuration in which the light emitting layer having the longer peak wavelength of the emitted light is disposed closer to the anode 21, the change in the color is less with respect to the change in the voltage applied to the electrode, and An organic EL element that emits light with high efficiency can be realized, and when a voltage applied between the anode 21 and the cathode 22 is changed, a coordinate value x in a chromaticity coordinate of light extracted outside; The range of change from the coordinate value y can be suppressed to 0.05 or less. Range of applied voltage when changing the voltage to be applied here is usually in the range where the luminance is ^{100cd / m 2 ~10000cd / m 2} , is a range of at least 4000cd / m ² ~6000cd / m ² . Further, the light extracted outside is light obtained by superimposing the light from the light emitting layers 23a, 23b, and 23c. In this specification, the chromaticity coordinates are defined in accordance with CIE1931 defined by the International Commission on Illumination (CIE).

  The multilayer light emitting unit 23 in the present embodiment is configured by stacking three light emitting layers 23a, 23b, and 23c, and emits white light as a whole. However, as a modification of the present embodiment, a light emitting layer that emits light having a wavelength different from the wavelength emitted by each of the light emitting layers 23a, 23b, and 23c is provided, for example, a multilayer that emits light having a wavelength different from white. You may comprise a light emission part. Furthermore, as another modification, the multilayer light emitting unit 23 may be configured by four or more light emitting layers. That is, the color of light emitted from each light emitting layer can be appropriately selected according to the color of light extracted from each organic EL element. In addition, the color of light extracted from the organic EL element is white, a color different from white, or the number of light emitting layers is three, or four or more. Even if each light emitting layer is arranged closer to the anode 21 as the light emitting layer having a longer peak wavelength of the emitted light, the color change with respect to the change in the voltage applied to the electrode is small and high. An organic EL element that emits light efficiently can be realized.

<B> Anode In this embodiment, the anode 21 is provided on the support substrate 10. As the anode 21, one having a low electric resistance is preferably used. At least one of the anode 21 and the cathode 22 has light transmittance. For example, when a bottom emission type organic EL element is used, an anode 21 having light transmittance and a high light transmittance in the visible light region is preferably used. As a material of the anode 21, a conductive metal oxide film, a translucent metal thin film, or the like can be used. More specifically, examples of the material of the anode 21 include indium oxide, zinc oxide, tin oxide, indium tin oxide (abbreviated as ITO), and indium zinc oxide (abbreviated as IZO). Examples thereof include metal oxides and conductive metals such as gold, platinum, silver, and copper. Among these, as the anode 21, ITO, IZO, tin oxide, or the like can be suitably used. In the case of a top emission type organic EL element, a mode in which the anode 21 is formed of a material that reflects light from the multilayer light emitting unit 5 to the cathode 22 side can be suitably employed. In the case of the top emission type, for example, a metal thin film having a thickness that reflects light may be provided as the anode 21.

  The film thickness of the anode 21 can be appropriately selected in consideration of light transmittance and electrical conductivity, and is, for example, 5 nm to 10 μm, preferably 10 nm to 1 μm, and more preferably 20 nm to 500 nm. It is.

<C> Cathode In this embodiment, the cathode 22 is provided by being stacked on the multilayer light emitting unit 23. The material of the cathode 22 is preferably a material having a small work function and easy electron injection into the light emitting layer, and a material having high electrical conductivity. Further, when light is extracted from the anode 21 side, the material of the cathode 22 is preferably a material having a high visible light reflectance in order to reflect the light from the multilayer light emitting unit 20 to the anode 21 side.

  As a material of the cathode 22, for example, a metal such as an alkali metal, an alkaline earth metal, a transition metal, and a Group 13 metal of the periodic table can be used. More specifically, as the material of the cathode 22, for example, lithium, sodium, potassium, rubidium, cesium, beryllium, magnesium, calcium, strontium, barium, aluminum, scandium, vanadium, zinc, yttrium, indium, cerium, samarium, Metals such as europium, terbium, ytterbium; alloys of two or more of these metals; from one or more of these metals and gold, silver, platinum, copper, manganese, titanium, cobalt, nickel, tungsten, tin Materials such as alloys with one or more selected; or graphite or graphite intercalation compounds. Examples of alloys include magnesium-silver alloys, magnesium-indium alloys, magnesium-aluminum alloys, indium-silver alloys, lithium-aluminum alloys, lithium-magnesium alloys, lithium-indium alloys, calcium-aluminum alloys, and the like. it can. A transparent conductive electrode can be adopted as the cathode 22. As the transparent conductive electrode, for example, a conductive metal oxide or a conductive organic material can be used. Specifically, as a conductive metal oxide, for example, indium oxide, zinc oxide, tin oxide, and indium tin oxide (ITO) or indium zinc oxide (IZO) which are composites thereof; For example, organic compounds such as polyaniline or a derivative thereof, polythiophene or a derivative thereof may be used. Note that the cathode may have a laminated structure of two or more layers.

  The thickness of the cathode can be appropriately selected in consideration of electric conductivity and durability, but is, for example, 10 nm to 10 μm, preferably 20 nm to 1 μm, and more preferably 50 nm to 500 nm.

<D> Arbitrary Constituent Layer The organic EL element 1 shown in FIG. 1 shows a form in which a multilayer light emitting section 23 is provided between an anode 21 and a cathode 22. However, the configuration of the layer provided between the anode 21 and the cathode 22 is not limited to the layer configuration shown in FIG. It is only necessary to provide the multilayer light emitting portion 23 between the anode 21 and the cathode 22 as an essential configuration, and one or more other optional layers may be provided. Examples of the optional constituent layer that can be provided in the light emitting function unit 20 include a hole injection layer, a hole transport layer, a hole block layer, an electron injection layer, an electron transport layer, and an electron block layer.

  Examples of the layer that can be provided between the anode 21 and the multilayer light emitting unit 23 include a hole injection layer, a hole transport layer, and an electron block layer. When both the hole injection layer and the hole transport layer are provided between the anode 21 and the multilayer light emitting part 23, the layer located on the side close to the anode 21 is called the hole injection layer, and the multilayer light emission. The layer located on the side close to the part is referred to as a hole transport layer.

  Examples of the layer that can be provided between the cathode 22 and the multilayer light emitting unit 23 include an electron injection layer, an electron transport layer, and a hole blocking layer. When both the electron injection layer and the electron transport layer are provided between the cathode 22 and the multilayer light emitting unit 23, the layer located on the side close to the cathode 22 is referred to as an electron injection layer. A layer located on the side close to 23 is referred to as an electron transport layer.

  The electron injection layer and the hole injection layer may be collectively referred to as a charge injection layer. The electron transport layer and the hole transport layer may be collectively referred to as a charge transport layer. The hole blocking layer and the electron blocking layer may be collectively referred to as a charge blocking layer.

Hereinafter, arbitrary constituent layers (not shown) will be described in detail.
<D1> Hole Injection Layer The hole injection layer is a layer having a function of improving hole injection efficiency from the anode. The hole injection layer is a layer having a function of improving hole injection efficiency from the anode. As the hole injection material constituting the hole injection layer, phenylamine, starburst amine, phthalocyanine, vanadium oxide, molybdenum oxide, ruthenium oxide, aluminum oxide, etc., amorphous carbon, polyaniline, polythiophene derivatives And so on.

  As the layer thickness of the hole injection layer, the optimum value varies depending on the material to be used, the driving voltage and the luminous efficiency are selected to be appropriate values, and at least a thickness that does not cause pinholes is required. If it is too high, the drive voltage of the element becomes high, which is not preferable. Accordingly, the thickness of the hole injection layer is, for example, 1 nm to 1 μm, preferably 2 nm to 500 nm, and more preferably 5 nm to 200 nm.

<D2> Hole transport layer The hole transport layer is a layer having a function of improving hole injection from the anode, the hole injection layer, or the hole transport layer closer to the anode.
As the hole transport material constituting the hole transport layer, polyvinylcarbazole or a derivative thereof, polysilane or a derivative thereof, a polysiloxane derivative having an aromatic amine in a side chain or a main chain, a pyrazoline derivative, an arylamine derivative, a stilbene derivative, Triphenyldiamine derivative, polyaniline or derivative thereof, polythiophene or derivative thereof, polyarylamine or derivative thereof, polypyrrole or derivative thereof, poly (p-phenylene vinylene) or derivative thereof, or poly (2,5-thienylene vinylene) or Examples thereof include derivatives thereof.

  Among these hole transport materials, as the hole transport material, polyvinyl carbazole or a derivative thereof, polysilane or a derivative thereof, a polysiloxane derivative having an aromatic amine compound group in a side chain or a main chain, polyaniline or a derivative thereof, Polymeric hole transport materials such as polythiophene or derivatives thereof, polyarylamine or derivatives thereof, poly (p-phenylene vinylene) or derivatives thereof, or poly (2,5-thienylene vinylene) or derivatives thereof are preferable, and polyvinyl More preferred are carbazole or derivatives thereof, polysilane or derivatives thereof, polysiloxane derivatives having an aromatic amine in the side chain or main chain, and the like. In the case of a low-molecular hole transport material, it is preferably used by being dispersed in a polymer binder.

  The film thickness of the hole transport layer differs depending on the material used, and is selected so that the drive voltage and the light emission efficiency are appropriate, and at least a thickness that does not cause pin holes is required. If it is too high, the drive voltage of the element becomes high, which is not preferable. Therefore, the thickness of the hole transport layer is, for example, 1 nm to 1 μm, preferably 2 nm to 500 nm, and more preferably 5 nm to 200 nm.

<D3> Electron Block Layer The electron block layer is a layer having a function of blocking electron transport. The hole injection layer or the hole transport layer may also serve as the electron block layer. As an electron block layer, the various materials illustrated as a material of the said positive hole injection layer or a positive hole transport layer can be used, for example.

<D4> Electron Injection Layer The electron injection layer is a layer having a function of improving the efficiency of electron injection from the cathode. The electron transport layer is a layer having a function of improving electron injection from the cathode, the electron injection layer, or the electron transport layer closer to the cathode. The hole blocking layer is a layer having a function of blocking hole transport. In some cases, the electron injection layer or the electron transport layer also serves as a hole blocking layer.

  The electron injecting material constituting the electron injecting layer can be appropriately selected according to conditions such as the type of the multilayer light emitting part. Examples of the material constituting the electron injection layer include alkali metals, alkaline earth metals, alloys containing one or more of the above metals, oxides of the metals, halides and carbonates, and mixtures of the above substances. Can be mentioned. Alkali metals or their oxides, halides and carbonates include lithium, sodium, potassium, rubidium, cesium, lithium oxide, lithium fluoride, sodium oxide, sodium fluoride, potassium oxide, potassium fluoride, rubidium oxide, fluorine. Examples thereof include rubidium chloride, cesium oxide, cesium fluoride, and lithium carbonate. Examples of alkaline earth metals or oxides, halides and carbonates thereof include magnesium, calcium, barium, strontium, magnesium oxide, magnesium fluoride, calcium oxide, calcium fluoride, barium oxide, barium fluoride, Examples thereof include strontium oxide, strontium fluoride, and magnesium carbonate.

  The electron injection layer may be a laminate in which two or more layers are laminated. Specific examples of the laminated body include LiF / Ca. The thickness of the electron injection layer is preferably about 1 nm to 1 μm.

<D5> Electron transport layer As an electron transport material constituting the electron transport layer, oxadiazole derivatives, anthraquinodimethane or derivatives thereof, benzoquinone or derivatives thereof, naphthoquinone or derivatives thereof, anthraquinones or derivatives thereof, tetracyanoanthraquino Dimethane or derivatives thereof, fluorenone derivatives, diphenyldicyanoethylene or derivatives thereof, diphenoquinone derivatives, or metal complexes of 8-hydroxyquinoline or derivatives thereof, polyquinoline or derivatives thereof, polyquinoxaline or derivatives thereof, polyfluorene or derivatives thereof, etc. be able to.

  Among these, as an electron transport material, an oxadiazole derivative, benzoquinone or a derivative thereof, anthraquinone or a derivative thereof, a metal complex of 8-hydroxyquinoline or a derivative thereof, a polyquinoline or a derivative thereof, a polyquinoxaline or a derivative thereof, a polyfluorene Or a derivative thereof is preferable, and 2- (4-biphenylyl) -5- (4-t-butylphenyl) -1,3,4-oxadiazole, benzoquinone, anthraquinone, tris (8-quinolinol) aluminum, and polyquinoline are further included. preferable.

  The film thickness of the electron transport layer varies depending on the material used, and can be selected so that the drive voltage and the light emission efficiency are appropriate. The lower limit of the thickness is preferably at least a thickness that does not cause pinholes. Further, the upper limit of the thickness is preferably an upper limit such that the driving voltage of the element is not too high. Although it depends on the material, the thickness of the electron transport layer is, for example, 1 nm to 1 μm, preferably 2 nm to 500 nm, and more preferably 5 nm to 200 nm.

<E> Combination of Layer Configurations of Light-Emitting Function Units As described above, the light-emitting function unit may employ various layer configurations as its embodiment. Specific examples of the layer structure that can be taken by the light emitting function unit are shown below.
(A) Anode / multilayer light emitting part / cathode (b) anode / hole injection layer / multilayer light emission part / cathode (c) anode / multilayer light emission part / electron injection layer / cathode (d) anode / hole injection Layer / multilayer light emitting part / electron injection layer / cathode (e) anode / hole injection layer / hole transport layer / multilayer light emission part / cathode (f) anode / multilayer light emission part / electron transport layer / electron injection layer / Cathode (g) anode / hole injection layer / hole transport layer / multilayer light emitting part / electron injection layer / cathode (h) anode / hole injection layer / multilayer light emitting part / electron transport layer / electron injection layer / Cathode (i) Anode / hole injection layer / hole transport layer / multi-layer light emitting part / electron transport layer / charge injection layer / cathode (where the symbol “/” indicates two layers sandwiching the symbol “/”) Are adjacent to each other, and so on.

In the embodiment shown in FIG. 1 and the like, a set of multilayer light emitting units 23 is provided. However, as a modification thereof, a mode in which two or more sets of multi-layer light emitting portions are provided in an overlapping manner can be adopted. Here, in any one of the layer configurations of (a) to (i) above, if the laminated body sandwiched between the anode and the cathode is a “repeating unit A”, for example, two sets of multilayer light emission As a layer configuration of the organic EL element including the portion 23, a layer configuration shown in the following j) may be employed.
(J) Anode / (repeat unit A) / charge generation layer / (repeat unit A) / cathode

Further, as an organic EL device having three or more sets of multi-layer light emitting portions, when “(repeating unit A) / charge injection layer” is “repeating unit B”, for example, the layer configuration of (k) below may be mentioned. it can.
(K) Anode / (Repeating unit B) _n / (Repeating unit A) / Cathode

The symbol “n” represents an integer of 2 or more, and (repeating unit B) _n represents a laminated body in which n repeating units B are laminated.
In the layer configurations j) and k), each layer other than the anode, electrode, cathode, and light emitting layer may be omitted as necessary.

  The charge generation layer is a layer that generates holes and electrons by applying an electric field. Examples of the charge generation layer include a thin film made of vanadium oxide, indium tin oxide (abbreviated as ITO), molybdenum oxide, or the like.

  Furthermore, as another arbitrary constituent layer, for example, an insulating layer having a thickness of 2 nm or less may be provided adjacent to the electrode in order to improve adhesion with the electrode or improve charge injection from the electrode. . Further, as another optional constituent layer, a thin buffer layer may be inserted at the interface between the adjacent layers in order to improve the adhesion of the interface or prevent mixing.

  In the embodiment shown in FIG. 1 and the like, an embodiment in which the anode 21 is provided on the support substrate 10 is shown. In these cases, in each of the above forms a) to i), the layers are arranged on the support substrate in order from the layer shown on the left side (the anode 21 side). On the other hand, as the organic EL element of the present invention, a form in which a cathode is disposed on a support substrate can be employed. In this case, in each of the above forms a) to i), the layers are arranged on the support substrate in order from the layer shown on the right side (cathode side).

<1.4. Heat dissipation layer>
The heat dissipation layer 60 is a layer that exhibits high thermal radiation and has a thermal emissivity of 0.70 or more. In this specification, thermal radiation refers to a phenomenon in which thermal energy is released from an object as an electromagnetic wave, or the electromagnetic wave (Iwanami Physical and Chemical Dictionary, Iwanami Shoten, 1998, 5th edition). The heat emissivity of the heat dissipation layer 60 is 0.70 or more, preferably 0.85 or more. From the viewpoint of releasing heat, the upper limit of the thermal emissivity is not particularly specified. Thermal emissivity is the amount of energy emitted from the surface of a material at a certain temperature and the amount of energy emitted from a black body (a virtual material that absorbs 100% of the energy given by radiation) at the same temperature as the certain temperature. It means the ratio. Thermal emissivity can be measured according to Fourier transform infrared spectroscopy (FT-IR). Examples of the material having high thermal radiation include black materials, and a pigment component of black paint can be suitably used. Examples thereof include a mixed material of carbon material and plastic material (carbon plastic), TiO ₂ doped with a predetermined metal element, colloid in which titania and predetermined metal fine particles are dispersed, Fe ₃ O _{4 and the} like.

  The heat dissipation layer 60 is preferably formed of a material having not only a high heat radiation property but also a high heat conductivity. In this specification, heat conduction refers to a phenomenon in which heat is transferred from a high-temperature part to a low-temperature part of an object without energy transfer due to movement of material or radiation (Iwanami Physical and Chemical Dictionary, Iwanami Shoten, 1998, 5th edition). The heat dissipation layer 60 exhibits high thermal radiation and preferably exhibits high thermal conductivity. The thermal conductivity is preferably 1 W / mK or more, more preferably 10 W / mK or more. More preferably, it is 200 W / mK. From the viewpoint of releasing heat, the upper limit of the thermal conductivity is not particularly specified. Thermal conductivity refers to the ratio of the amount of heat that flows perpendicularly to a unit time through a unit area of an isothermal surface inside an object and the temperature gradient in this direction (Iwanami Encyclopedia, ibid.). The thermal conductivity can be measured by, for example, the method of ASTM D5470 (American Society For Testing and D5470). Examples of the material having high thermal conductivity include aluminum, copper, silver, a ceramic material, and an inorganic material selected from the group consisting of two or more kinds of alloys selected from these, or a highly thermal conductive resin. Examples of the highly heat conductive resin include an epoxy resin, a melamine resin, and an acrylic resin.

  The heat dissipation layer 60 may be formed as a single layer or may have a laminated structure including two or more layers. Examples of a single layer include a layer formed by dispersing high thermal conductivity fine particles in a resin material, mixing a black pigment, and applying the resin material to a substrate. In addition, examples of the heat dissipation layer 60 including a plurality of layers include a laminated body including a high thermal conductivity layer and a black material layer exhibiting high thermal radiation. The heat dissipation layer including a plurality of layers may be configured by laminating a plurality of high thermal radiation layers and high thermal conductivity layers that exhibit high thermal radiation, such as a black material layer.

<1.5. Top emission type and bottom emission type>
In order to emit light from the light emitting layer, the organic EL element normally allows light to pass through all the layers on either side of the multilayer light emitting section. Specifically, for example, in the case of an organic EL device having a configuration of support substrate / anode / hole injection layer / hole transport layer / multilayer light emitting part / electron transport layer / electron injection layer / cathode / sealing substrate, All of the substrate, the anode, the hole injection layer, and the hole transport layer can transmit light, and can be a so-called bottom emission type element. Alternatively, all of the electron transport layer, the electron injection layer, the cathode, and the sealing member can transmit light and can be a so-called top emission type element.

  Further, in the case of an organic EL device having a configuration of support substrate / cathode / electron injection layer / electron transport layer / multilayer light emitting part / hole transport layer / hole injection layer / anode / sealing substrate, cathode, electron injection layer In addition, all of the electron transport layer can transmit light, so-called bottom emission type elements, or all of the hole transport layer, hole injection layer, anode, and sealing member can transmit light. Thus, a so-called top emission type element can be obtained. Here, it is preferable that the light can be transmitted from the light emitting layer to the light emitting layer having a visible light transmittance of 30% or more. In the case of an element that requires light emission in the ultraviolet region or infrared region, an element having a transmittance of 30% or more in the region is preferable.

  In the present invention, a heat dissipation layer is provided. When the heat dissipation layer is formed of a light-impermeable material, the light is taken from the side of the substrate opposite to the side where the heat dissipation layer is provided.

<Second Embodiment of Organic EL Element>
A second embodiment of the present invention will be described with reference to FIG. In FIG. 2, sectional drawing of the organic EL element 2 of 2nd Embodiment is shown. In FIG. 2, members that are the same as those in the first embodiment are denoted by the same reference numerals as those in FIG. 1, and differences from the first embodiment will be mainly described below.

  As shown in FIG. 2, the heat dissipation layer 61 may be provided on the sealing substrate 30. In the organic EL element 2 shown in FIG. 2, the radioactive layer 61 is provided on the main surface of the sealing substrate 31 opposite to the main surface on the light emitting function unit 20 side. A glass substrate or a plastic sheet is used for the sealing substrate 31, and the sealing substrate 31 and the support substrate 10 are fused.

<Third Embodiment of Organic EL Element>
A third embodiment of the present invention and its modification will be described with reference to FIGS. 3-1 to 3-5. FIG. 3A is a cross-sectional view of the organic EL element 3A of the third embodiment (hereinafter may be referred to as “element of the third embodiment”). In FIG. 3A, members that are the same as those in the first embodiment are denoted by the same reference numerals as those in FIG. 1, and differences from the first embodiment will be mainly described below.

  The organic EL element 3A is a top emission type element that takes light from the sealing substrate side. In the organic EL element 3A, a heat radiation layer 63 is provided on the main surface of the support substrate 10 opposite to the main surface on the light emitting function unit 20 side. The heat radiation layer 63 is composed of two layers. One layer is a black material layer 63a, and the other layer is an aluminum layer 63b as a high thermal conductivity layer. In the heat dissipation layer 63, the aluminum layer 63 b is provided in contact with the support substrate 10. Heat is transmitted to the support substrate 10 by the heat generation of the light emitting layer. In particular, when a material having low thermal conductivity such as a glass substrate is used as the support substrate 10, the heat tends to stagnate in the support substrate 10. However, in the organic EL element 3A, since the aluminum layer 63b having high thermal conductivity is provided in contact with the support substrate 10, the diffusion of heat in the support substrate 10 and the aluminum layer 63b is promoted and the heat is increased. It helps to escape to the outside of the support substrate 10. Further, the aluminum layer 63b is provided with a black material layer 63a formed by applying a black paint, and radiation of heat transferred to the black material layer 63a to the outside is promoted.

FIG. 3-2 shows an organic EL element 3B which is a modification of the element of the third embodiment. In the organic EL element 3A, the heat dissipation layer 63 is provided only on one main surface of the support substrate 10. However, in the organic EL element 3B, the heat dissipation layer 63 is provided on both main surfaces of the support substrate 10. Thus, by providing the heat dissipation layer 63 on both surfaces of the support substrate 10, heat generated by the light emitting function unit 20 as a heat source can be more smoothly transferred to the entire support substrate 10, and heat dispersibility can be further improved. . In the example illustrated in FIG. 3B, the support substrate 10 and the heat dissipation layer 63 are configured in the following order in order from the light emitting function unit 20 toward the outside (in the drawing, in order from the light emitting function unit 20 downward). .
(I) Aluminum layer 63b / black material layer 63a / support substrate 10 / black material layer 63a / aluminum layer 63b

The positions of the black material layer 63a and the aluminum layer 63b can be changed depending on the design convenience such as electrode formation. For example, as in the modification shown in FIG. 3C, the support substrate 10 and the heat dissipation layer (black material layer 63a and aluminum layer 63b) are configured in the following order from the light emitting function unit 20 (not shown). Also good. In the following, in FIG. 3C to FIG. 3E, the upper configuration of the light emitting function unit 20 and the like is the same as that in FIG.
(II) Black material layer 63a / aluminum layer 63b / support substrate 10 / aluminum layer 63b / black material layer 63a

Furthermore, you may laminate | stack in order of following (III), (IV), and (V) (not shown).
(III) Black material layer 63a / aluminum layer 63b / support substrate 10 / black material layer 63a / aluminum layer 63b
(IV) Aluminum layer 63b / black material layer 63a / support substrate 10 / aluminum layer 63b / black material layer 63a
(V) Aluminum layer 63b / black material layer 63a / support substrate 10 / black material layer 63a / aluminum layer 63b / black material layer 63a
From the viewpoint of heat dissipation, it is preferable to laminate in the order shown in (V).

  FIG. 3-4 shows still another modification of the element of the third embodiment. In the organic EL element 3B, the heat dissipation layer 63 including two layers of the black material layer 63a and the aluminum layer 63b is provided. However, in the modification shown in FIG. 3-4, the black material layer 63a is formed on both surfaces of the aluminum layer 63b. Is provided. Thus, the form which provides the black-type material layer 63a on both surfaces is a preferable form in the point that heat dissipation can be improved more.

  FIG. 3-5 shows still another modified example of the element of the third embodiment. In the modification shown in FIG. 3-5, only the aluminum layer 63b is provided on the main surface of the support substrate 10 on the light emitting function unit side (the upper surface of the support substrate 10 in FIG. 3-5). It can be employed when a black material layer is not desired to be provided on the side where the light emitting function part is provided.

  FIG. 3-6 shows still another modification of the element of the third embodiment. In the modification shown in FIG. 3-6, a black material layer 63a and an aluminum layer 63b are provided on the main surface of the support substrate 10 on the light emitting function unit side (the upper surface of the support substrate 10 in FIG. 3-6). .

<Fourth Embodiment>
A fourth embodiment of the present invention will be described with reference to FIG. FIG. 4 shows a cross-sectional view of the organic EL element 4A of the fourth embodiment. In FIG. 4, members that are the same as those in the third embodiment are denoted by the same reference numerals as those in FIG. 1, and differences from the first embodiment will be mainly described below.

  The organic EL element 4A is a bottom emission type element that collects light from the support substrate 10 side. Therefore, in the organic EL element 4 </ b> A, the heat dissipation layer 63 is not provided on the support substrate 10 but is provided on the upper surface of the sealing substrate 30. Thus, the heat dissipation layer 63 can also be provided on the sealing substrate. As a modification of the example shown in FIG. 4, when the heat dissipation layer 63 is provided on the sealing substrate 30, a resin having high thermal conductivity is filled between the light emitting function unit 20 and the sealing substrate 30, and the light emitting function unit 20 is provided. The thermal conductivity from the sealing substrate 30 to the sealing substrate 30 may be further improved.

2. The manufacturing method of the organic EL element of this invention This invention provides the suitable method in order to manufacture the organic EL element of the said invention. The organic EL device of the present invention is not limited to the manufacturing method shown below.

  The organic EL device of the present invention can be produced by sequentially laminating each constituent member constituting the device on a support substrate. The method for forming the layer can be appropriately selected depending on the material of the layer, the properties of the underlying layer, and the like, and can be manufactured using various film forming methods for forming a thin film using an organic material or an inorganic material. .

<A> Formation method of multilayer light emitting part The organic EL device of the present invention has a multilayer light emitting part including a plurality of light emitting layers, and the light emitting layer having a longer peak wavelength of emitted light is closer to the anode. Be placed.

  Each light-emitting layer constituting the multilayer light-emitting portion can be formed by, for example, a coating method in which a coating solution in which the material constituting the light-emitting layer is dissolved in a solvent is applied. Any solvent may be used as long as it dissolves the material constituting the light-emitting layer. For example, water, chlorine-based solvents such as chloroform, methylene chloride, and dichloroethane, ether-based solvents such as tetrahydrofuran, and aromatic carbonization such as toluene and xylene. Examples thereof include hydrogen solvents, ketone solvents such as acetone and methyl ethyl ketone, and ester solvents such as ethyl acetate, butyl acetate and ethyl cellosolve acetate.

  Examples of coating methods for forming a light emitting layer include spin coating, casting, micro gravure coating, gravure coating, bar coating, roll coating, wire bar coating, dip coating, spray coating, and screen printing. Method, flexographic printing method, offset printing method, and inkjet printing method. Each of the light emitting layers can be formed by applying the above-described coating liquid onto the support substrate 10 on which the anode 21 is formed using one of these coating methods.

As a preferred embodiment relating to the step of forming the multilayer light emitting part, the following production method may be mentioned.
In the method of manufacturing an organic EL element including a multilayer light emitting portion including a plurality of light emitting layers, and forming the multilayer light emitting portion of the multilayer,
A first coating step of forming a first coating film by coating a first coating liquid containing a material for forming the first light emitting layer on the coating layer;
A first curing step of curing the first coating film to form a first light emitting layer on the coated layer,
In the first curing step, the first light emitting layer is insolubilized with respect to the second coating liquid containing a material for forming the second light emitting layer formed subsequent to the first light emitting layer. Curing the coating film,
Manufacturing method of organic EL element.

  When forming the light emitting layer, the first light emitting layer previously formed has insolubility with respect to the coating solution used when forming the second light emitting layer laminated on the first light emitting layer. It is preferable to do so. For example, in the case of forming a light emitting layer containing a polymer compound as a main component, it is preferable to insolubilize the solvent so as to have resistance.

  Specifically, after forming a coating film by a coating method using a coating solution containing a material mainly constituting each light emitting layer and a crosslinking agent, the material mainly constituting the light emitting layer is crosslinked with a crosslinking agent. Thus, the light emitting layer can be insolubilized. Crosslinking with a crosslinking agent can be performed by applying predetermined energy such as light or heat. The material mainly constituting the light emitting layer is a material having the highest mass concentration in the light emitting layer, and among the materials constituting the light emitting layer, a material that emits fluorescence and / or phosphorescence (hereinafter referred to as a light emitting material). Is equivalent). In addition, as a material mainly constituting the light emitting layer, a material having in its molecule a group that crosslinks when energy is applied (hereinafter sometimes referred to as a crosslinkable group) may be used. In this case, it is not necessary to add a crosslinking agent as described above to the coating solution used when forming the light emitting layer using the coating method.

  Examples of the crosslinking group include a vinyl group. Specifically, as a material mainly constituting the light-emitting layer, a material using a polymer compound containing a residue obtained by removing at least one hydrogen atom from benzocyclobutane (BCB) in the main chain and / or side chain is exemplified. be able to.

  In addition to the material mainly constituting the light emitting layer, the crosslinking agent added to the coating solution includes vinyl group, acetyl group, butenyl group, acrylic group, acrylamide group, methacryl group, methacrylamide group, vinyl ether group, vinylamino group. And a compound having a polymerizable substituent selected from the group consisting of a group, a silanol group, a cyclopropyl group, a cyclobutyl group, an epoxy group, an oxetane group, a diketene group, an episulfide group, a lactone group, and a lactam group. As the crosslinking agent, for example, a polyfunctional acrylate is preferable, and dipentaerythritol hexaacrylate (DPHA), trispentaerythritol octaacrylate (TPEA), and the like are more preferable.

  A mode in which a red light emitting layer 23a, a green light emitting layer 23b, and a blue light emitting layer 23c are sequentially stacked on the anode 21 as in the organic EL element 1 shown in FIG. 1 will be described. First, the red light emitting layer 23a is formed. Specifically, a coating solution in which the material constituting the red light emitting layer 23a is dissolved is applied on the surface of the anode 21 by the above-described coating method. Next, the coated red light emitting layer 23a is obtained by heating or irradiating the applied film with light. The red light emitting layer 23a thus cross-linked does not elute even when a coating liquid is applied to form the green light emitting layer 23b.

  Next, the green light emitting layer 23b is formed. Specifically, a coating solution in which the material constituting the green light emitting layer 23b is dissolved is applied on the surface of the red light emitting layer 23a by the above-described coating method. Next, the coated green light emitting layer 23b is obtained by heating or irradiating the applied film with light. The cross-linked green light emitting layer 23b does not elute even when a coating solution is applied to form the blue light emitting layer 23c.

  Next, a blue light emitting layer 23c is formed. Specifically, the blue light-emitting layer 23c is obtained by applying a coating solution in which the material constituting the blue light-emitting layer 23c is dissolved onto the surface of the green light-emitting layer 23b by the above-described application method and drying.

  Thus, by making the luminescent layer to which the coating solution is applied insoluble in the coating solution in advance, it is possible to prevent the luminescent layer from being dissolved when the coating solution is applied to the surface of the luminescent layer. . Thereby, control of the film thickness of each light emitting layer becomes easy, and the light emitting layer of the intended film thickness can be formed easily.

The multilayer light emitting unit 23 is laminated so that a light emitting layer having a longer wavelength of emitted light is arranged closer to the anode 21. However, the stacking order is not limited. For example, the anode 21 may be used as a base layer, and a light emitting layer having a longer wavelength of emitted light may be sequentially stacked, or a layer closer to the cathode 22 may be used as a base layer. You may laminate | stack in order from the light emitting layer with the short wavelength of the light to light-emit.
Further, as in the embodiment shown in FIG. 1, the anode 21 is provided closer to the support substrate 10 than the multilayer light emitting unit 23, and the cathode 22 is provided on the opposite side of the support substrate 10 with respect to the multilayer light emitting unit 23. As a modification, the arrangement of the anode 21 and the cathode 22 may be reversed.

<B> Method for Forming Anode Examples of a method for producing the anode include a vacuum deposition method, a sputtering method, an ion plating method, a plating method, and the like. Further, as the anode, an organic transparent conductive film such as polyaniline or a derivative thereof, polythiophene or a derivative thereof may be used.

<C> Method for Forming Cathode As a method for producing the cathode, a vacuum deposition method, a sputtering method, a CVD method, an ion plating method, a laser ablation method, a laminating method for pressing a metal thin film, and the like are used.

<D> Method for Forming Arbitrary Constituent Layer As described above, the light emitting functional unit 20 can further include arbitrary constituent layers such as a charge injection layer and a charge transport layer. These layers can be provided by various thin film forming methods using the material depending on the type of the material. The formation method of these layers is shown below.

  As a method for forming the hole injection layer, for example, the film can be formed by a coating method in which a coating solution in which the above-described hole injection material is dissolved in a solvent is applied. Any solvent may be used as long as it dissolves the hole injecting material. For example, water, chloroform, methylene chloride, dichloroethane and other chlorine solvents, tetrahydrofuran and other ether solvents, toluene, xylene and other aromatic hydrocarbon systems. Examples include solvents, ketone solvents such as acetone and methyl ethyl ketone, and ester solvents such as ethyl acetate, butyl acetate, and ethyl cellosolve acetate.

  As a coating method for forming a hole injection layer, a spin coating method, a casting method, a micro gravure coating method, a gravure coating method, a bar coating method, a roll coating method, a wire bar coating method, a dip coating method, a spray coating method, Examples thereof include a screen printing method, a flexographic printing method, an offset printing method, and an ink jet printing method.

  As a method for forming a hole transport layer, in the case of a low molecular hole transport material, a method of forming a film from a mixed solution with a polymer binder can be mentioned. The method by the film-forming from can be mentioned.

  As a solvent used for film formation from a solution, any solvent capable of dissolving a hole transport material may be used. Chlorine solvents such as chloroform, methylene chloride and dichloroethane, ether solvents such as tetrahydrofuran, aromatics such as toluene and xylene. Examples thereof include hydrocarbon solvents, ketone solvents such as acetone and methyl ethyl ketone, and ester solvents such as ethyl acetate, butyl acetate, and ethyl cellosolve acetate. As a film forming method from a solution, the same coating method as the method mentioned as the method of forming a hole injection layer can be mentioned.

  As the polymer binder to be mixed, those not extremely disturbing charge transport are preferable, and those having low absorption of visible light are suitably used. Examples of the polymer binder include polycarbonate, polyacrylate, polymethyl acrylate, polymethyl methacrylate, polystyrene, polyvinyl chloride, and polysiloxane.

  Examples of the method for forming the electron injection layer include vapor deposition, sputtering, and printing.

  As a film formation method of the electron transport layer, in the case of a low molecular electron transport material, a vacuum deposition method from a powder, or a method by film formation from a solution or a molten state can be exemplified, and in a polymer electron transport material, Examples thereof include a method by film formation from a solution or a molten state. In film formation from a solution or a molten state, a polymer binder may be further used in combination. Examples of the method for forming an electron transport layer from a solution include the same film formation method as the method for forming a hole transport layer from a solution described above.

<E> Method of forming heat dissipation layer The heat dissipation layer can adopt various forms as described above. When producing a single heat dissipation layer, for example, a method of mixing a resin material that promotes thermal radiation, such as a black pigment, and applying this resin material to a substrate to form a layer is adopted. obtain. When a heat dissipation layer having a single layer and high thermal conductivity is used, for example, high thermal conductivity fine particles are dispersed in the resin material, a black pigment is mixed, and the resin material is applied to the substrate. For example, a method of forming a layer may be employed.

  Examples of the heat dissipation layer including a plurality of layers include a laminated body including a high thermal conductivity layer and a black material layer exhibiting high thermal radiation. As such a laminated body, the laminated body containing a highly heat conductive layer and a black material layer is mentioned, for example. For a laminate including a high thermal conductivity layer and a black material layer, for example, a paint containing a black pigment is applied to one or both sides of a high thermal conductivity sheet (high thermal conductivity layer) made of a material exhibiting high thermal conductivity. It can produce by doing. Such a composite sheet may be prepared in advance and bonded to a support substrate, or each layer may be formed on the support substrate in sequence. The heat dissipation layer 60 including a plurality of layers may be configured by laminating a plurality of high thermal radiation layers and high thermal conductivity layers that exhibit high thermal radiation, such as a black material layer.

  More specifically, for example, a black paint is applied to one main surface of an aluminum sheet to produce a sheet on which a black material layer is formed, and this is applied to a support substrate using an adhesive (not shown) or the like. The form which adheres is mentioned. Further, as another form, there is a form in which aluminum is vapor-deposited on a support substrate in advance and a black paint layer is applied to the surface of the formed aluminum layer to form a black material layer.

  The sheet-like heat radiation layer may be attached to the substrate with an adhesive interposed. As the adhesive, an adhesive having high thermal conductivity such as an acrylic adhesive or an epoxy adhesive is preferably used. Moreover, in the case of a glass substrate, an acrylic adhesive can be suitably used in terms of excellent adhesion to glass.

  Further, a sheet-like film having plasticity or flexibility may be fused to a glass substrate serving as a supporting substrate or a sealing substrate.

3. Apparatus equipped with the organic EL element of the present invention The organic EL element of the present invention is used in a planar light source, a lighting device, a display device and the like. Examples of the display device including the organic EL element 1 include a segment display device, a dot matrix display device, and a liquid crystal display device. In the dot matrix display device, the organic EL element is used as a pixel or a backlight, and in the liquid crystal display device, the organic EL element is used as a backlight.

  In the organic EL device of the present invention, when the voltage applied between the anode and the cathode is changed, the width of change between the coordinate value x and the coordinate value y in the chromaticity coordinate of the extracted light is respectively It can be made 0.05 or less, has little change in color, and is suitably used for the above-described planar light source, lighting device, and display device. In particular, as the lighting device, it is preferable that the color does not change when the brightness is adjusted by changing the voltage applied between the anode and the cathode, and the coordinates in the chromaticity coordinates of the light from the lighting device are preferable. Since the change width between the value x and the coordinate value y is preferably 0.05 or less, the organic EL element of the present invention is suitably used as an element for a lighting device.

  Similarly, the backlight of the dot matrix display device and the liquid crystal display device is preferably one that does not change color when the brightness is adjusted, and the coordinate value x in the chromaticity coordinates of the light from the backlight is Since the change width with respect to the coordinate value y is preferably 0.05 or less, the organic EL element of the present invention is also suitably used for a backlight. Further, by combining with a color filter, the organic EL element of the present invention can be suitably used as a pixel of a display device.

  Hereinafter, the present invention will be described in more detail while showing verification experiments and examples, but the present invention is not limited to the following examples.

<Production Example 1> Production of an organic EL device having a multilayer light emitting part An organic EL device was produced as follows. As the support substrate, a glass substrate was used, and an ITO film formed on the glass substrate by a sputtering method and patterned into a predetermined shape was used as an anode. An anode having a thickness of 150 nm was used. The support substrate on which the anode 21 is formed is washed with an alkaline detergent and ultrapure water, dried, and then UV-O ₃ apparatus (trade name “Model 312 UV-O ₃ cleaning system” manufactured by Technovision Co., Ltd.) Was subjected to UV-O ₃ treatment.

  Next, a suspension of poly (3,4) ethylenedioxythiophene / polystyrene sulfonic acid (trade name “BaytronP TP AI4083” manufactured by HC Starck Vitec Co., Ltd.) was filtered through a membrane filter having a pore size of 0.2 μm. . A thin film was formed on the anode by spin coating the liquid obtained by filtration. Next, the hot plate was heated at 200 ° C. for 10 minutes to obtain a hole injection layer having a thickness of 70 nm.

  Next, a red light emitting layer was laminated on the hole injection layer. First, xylene is used as a solvent, a light emitting material (manufactured by Summation, trade name “PR158”) is used as a material mainly constituting a red light emitting layer, and dipentaerythritol hexaacrylate (manufactured by Nippon Kayaku, A coating solution was prepared using a trade name “KAYARAD DPHA”). The weight ratio of the light emitting material to the cross-linking agent was 4: 1, and the ratio of the combined material of the light emitting material and the cross-linking agent in the coating solution was 1.0% by mass. The coating solution thus obtained was spin-coated to form a thin film on the hole injection layer. Next, it heated at 200 degreeC for 20 minute (s) in nitrogen atmosphere, and obtained the red light emitting layer with a film thickness of 10 nm. By performing such a heat treatment, the thin film was dried to remove the solvent, and the crosslinking agent was allowed to act to insolubilize the red light emitting layer in the coating solution to be applied next.

  Next, the green light emitting layer was laminated | stacked on the red light emitting layer. First, xylene is used as a solvent, a light emitting material (manufactured by Summation, product name “Green 1300”) is used as a material mainly constituting the green light emitting layer, and dipentaerythritol hexaacrylate (manufactured by Nippon Kayaku, A coating solution was prepared using a trade name “KAYARAD DPHA”). The weight ratio of the light emitting material to the cross-linking agent was 4: 1, and the ratio of the combined material of the light emitting material and the cross-linking agent in the coating solution was 1.0% by mass. A thin film was formed on the red light emitting layer by spin coating the coating solution thus obtained. Next, it heated at 200 degreeC for 20 minute (s) in nitrogen atmosphere, and obtained the green light emitting layer with a film thickness of 15 nm. By performing such a heat treatment, the thin film was dried to remove the solvent, and a cross-linking agent was allowed to act to insolubilize the green light emitting layer in the coating solution to be applied next.

  Next, a blue light emitting layer was laminated on the green light emitting layer. First, xylene was used as a solvent, and a coating solution was prepared using a light emitting material (manufactured by Summation Co., Ltd., trade name “BP361”) as a material mainly constituting the blue light emitting layer. The ratio of the blue light emitting material in the coating solution was 1.5% by mass. The coating solution thus obtained was spin-coated to form a thin film on the green light emitting layer. Next, it heated at 130 degreeC for 20 minute (s) in nitrogen atmosphere, and obtained the blue light emitting layer with a film thickness of 55 nm. In addition, the shape of the cross section cut by the plane perpendicular to the thickness direction of each light emitting layer was a square of 2 mm × 2 mm.

Next, the substrate on which the blue light emitting layer is formed is introduced into a vacuum deposition gas, and barium is vapor-deposited on the blue light emitting layer to form a thin film made of barium having a thickness of about 5 nm, and further made of barium. Aluminum was vapor-deposited on the thin film to form a thin film made of aluminum having a thickness of about 80 nm, and a cathode composed of a laminate of a thin film made of barium and a thin film made of aluminum was formed. Note that deposition of barium and aluminum was started after the degree of vacuum reached 5 × 10 ⁻⁵ Pa or less.

<Comparative Example 1> Production of Organic EL Element As Comparative Example 1, an organic EL element having a light emitting portion composed of only a single light emitting layer (hereinafter sometimes referred to as a white light emitting layer) emitting light in a white wavelength region was produced. . Since the manufacturing process other than the white light emitting layer is the same as the manufacturing process of the organic EL element of the embodiment, the redundant description is omitted and only the manufacturing process of the white light emitting layer will be described.

  First, xylene was used as a solvent, and a coating solution was prepared using a light emitting material (trade name “WP1330”, manufactured by Summation Co., Ltd.) as a material mainly constituting the white light emitting layer. The ratio of the luminescent material in the coating solution was 1.0% by mass. The thin film was formed on the positive hole injection layer by spin-coating the coating liquid obtained in this way on the board | substrate with which the positive hole injection layer was formed. Next, it heated at 130 degreeC for 20 minute (s) in nitrogen atmosphere, and obtained the white light emitting layer with a film thickness of 80 nm.

Comparative Example 2 Production of Organic EL Element As Comparative Example 2, an organic EL element different from the organic EL element of the example only in the stacking order of the three layers of the red light emitting layer, the green light emitting layer, and the blue light emitting layer was produced. did. A blue light emitting layer was disposed in the layer closest to the anode, a green light emitting layer was disposed in the middle layer, and a red light emitting layer was disposed in the layer closest to the cathode. Since the manufacturing steps other than the red light emitting layer, the green light emitting layer, and the blue light emitting layer are the same as the manufacturing steps of the organic EL element of the example, only the manufacturing steps of the red light emitting layer, the green light emitting layer, and the blue light emitting layer will be described. .

  First, a blue light emitting layer was laminated on the hole injection layer. Xylene is used as a solvent for the coating solution, a light emitting material (trade name “BP361” manufactured by Summation Co., Ltd.) is used as a material mainly constituting the blue light emitting layer, and dipentaerythritol hexaacrylate (manufactured by Nippon Kayaku Co., Ltd.) is used as a crosslinking agent , Trade name “KAYARAD DPHA”). The weight ratio of the light emitting material to the cross-linking agent was 4: 1, and the ratio of the combined material of the light emitting material and the cross-linking agent in the coating solution was 1.0% by mass. The coating solution thus obtained was spin-coated to form a thin film on the hole injection layer. Next, it heated at 130 degreeC for 20 minute (s) in nitrogen atmosphere, and obtained the blue light emitting layer with a film thickness of 55 nm. By performing such heat treatment, the thin film was dried to remove the solvent, and the cross-linking agent was allowed to act to insolubilize the blue light emitting layer in the coating solution to be applied next.

  Next, the green light emitting layer was laminated on the blue light emitting layer. First, xylene is used as a solvent, a light emitting material (manufactured by Summation, product name “Green 1300”) is used as a material mainly constituting the green light emitting layer, and dipentaerythritol hexaacrylate (manufactured by Nippon Kayaku, A coating solution was prepared using a trade name “KAYARAD DPHA”). The weight ratio of the light emitting material to the cross-linking agent was 4: 1, and the ratio of the combined material of the light emitting material and the cross-linking agent in the coating solution was 1.0% by mass. A thin film was formed on the blue light emitting layer by spin coating the coating solution thus obtained. Next, it heated at 200 degreeC for 20 minute (s) in nitrogen atmosphere, and obtained the green light emitting layer with a film thickness of 15 nm. By performing such a heat treatment, the thin film was dried to remove the solvent, and a cross-linking agent was allowed to act to insolubilize the green light emitting layer in the coating solution to be applied next.

  Next, the red light emitting layer was laminated on the green light emitting layer. First, xylene was used as a solvent, and a coating solution was prepared using a light emitting material (trade name “PR158”, manufactured by Summation Co., Ltd.) as a material mainly constituting the red light emitting layer. The ratio of the luminescent material in the coating solution was 1.0% by mass. The coating solution thus obtained was spin-coated to form a thin film on the green light emitting layer. Next, it heated at 200 degreeC for 20 minute (s) in nitrogen atmosphere, and obtained the red light emitting layer with a film thickness of 10 nm.

  A voltage was applied to each organic EL element of Production Example 1, Comparative Example 1, and Comparative Example 2 to measure luminance and chromaticity. In the measurement, the applied voltage was changed stepwise, and the luminance and chromaticity were measured for each applied voltage. The measurement results are shown in Table 1.

When changing the luminance to 100cd / m ² ~10000cd / m ² by changing the voltage to be applied, Examples, Comparative Example 1, the coordinate value x in the CIE chromaticity coordinates of the organic EL device of Comparative Example 2, y Table 2 shows the respective change widths.

As shown in Table 1 and Table 2, the organic EL device of Example 1, when the brightness by changing the voltage to be applied was changed from ^{100cd / m 2 ~10000cd / m 2} , the light extracted chromaticity The width of change between the coordinate value x and the coordinate value y in the coordinates was 0.016 or less, respectively.

As shown in Table 1, the organic EL element of Example 1 has a maximum current efficiency improved by providing three light emitting layers as compared with the organic EL element of Comparative Example 1 composed of only one light emitting layer. did.
Moreover, the organic EL element of Example 1 improved the maximum value of current efficiency as compared with the organic EL element of Comparative Example 2 by arranging the three light emitting layers in a predetermined arrangement.

  Moreover, as shown in Table 2, the organic EL device of Example 1 is more resistant to changes in voltage than the organic EL device of Comparative Example 1 having only one light emitting layer by providing three light emitting layers. There was little change in color. Moreover, the organic EL element of Example 1 had less change in color with respect to voltage change than the organic EL element of Comparative Example 2 by arranging the three light emitting layers in a predetermined arrangement.

<Verification experiments on heat dissipation and thermal conductivity>
The verification experiment was performed using a test apparatus as shown in FIG. Since the present invention is considered to be substantially independent of the structure of the light emitting function part of the organic EL element, a self-made point heater is used as a heat source, glass, an aluminum sheet coated with a material having a high thermal emissivity, and the like Evaluation was performed using. As shown in FIG. 5, a hot plate 81 is provided on the test stand 80, and a columnar heat conduction portion 83 is provided at the center thereof. The heat conducting portion 83 is made of brass, and a heat insulating sheet 82 is wound around the side surface of the heat conducting portion 83. A test substrate holding glass 12 is provided on the upper end portion of the heat conducting portion 83. Then, a test substrate 15 to be tested is placed on the test substrate holding glass 12. The temperature of the upper surface portion of the test substrate 15 is measured by the temperature sensor 84 from above. Radiant heat is measured from the upper surface of the test substrate 15.

  FIG. 6 shows a plan view of the test substrate 15 placed on the test substrate holding glass 12. Reference signs A to K shown on the test substrate 15 indicate measurement positions from above by the temperature sensor 84. Moreover, the broken line in the center indicates the position of the upper end surface of the heat conducting portion 83 below the test substrate holding glass 12. In this way, a heat source is provided at the center, and the thermal diffusivity of the test substrate 15 is measured by measuring a plurality of positions from one corner of the test substrate 15 to the center and the other corner on the opposite side. be able to.

  Each test substrate was evaluated as follows. First, for the heat dissipation effect, the decrease level of the maximum temperature (the central part of the test substrate) was used as an index. Specifically, the maximum temperature of the test substrate (temperature at the center) in Comparative Test Example 1 (glass substrate only) is set as the maximum value of the maximum temperature, and this maximum value is subtracted from the maximum temperature at the center of other test substrates. It was calculated as a difference. The lower the maximum temperature and the greater the difference between the maximum temperatures, the better the thermal radiation. In addition, for the soaking property (heat dispersibility), the temperature distribution indicated by the temperature at each measurement position in each test substrate was used as an index. The smaller the temperature distribution in the test substrate, the better the temperature uniformity.

<Execution test example 1>
As Test Example 1, the test substrate shown in FIG. As a test substrate of Example 1, a sheet made of a glass substrate 11 (thickness 0.7 mm) made of a highly thermally conductive aluminum sheet coated with black with high thermal emissivity and an adhesive for bonding the glass substrate ( A substrate provided with Kobe Steel, trade name: Kobebenets Aluminum (KS750), thermal conductivity 230 W / mK, thermal emissivity 0.86) was produced. Therefore, the test substrate of Example 1 is configured as a laminate in which the glass substrate 11 / aluminum layer 63b / black material layer 63a are sequentially laminated in order from the test substrate holding glass 12.

  The set temperature of the hot plate was set so as to be the temperature at which the test glass substrate of Comparative Test Example 1 was 90 ° C., and the test substrate was heated. It was judged that the temperature was stable in a state where the fluctuation of the temperature at the measurement point was within a range of ± 0.2 ° C., and the temperature was measured using the temperature sensor 84 at positions A to K shown in FIG.

<Execution test example 2>
Except that the test substrate shown in FIG. 7-2 was used, the test substrate was tested for thermal radiation and thermal uniformity in the same manner as in Test Example 1 described above. As shown in FIG. 7-2, the test substrate of Example 2 has a layer having high thermal conductivity and high thermal radiation on both surfaces of the glass substrate. That is, the test substrate of Example 3 is a laminate in which the black material layer 63a / aluminum layer 63b / glass substrate 11 / aluminum layer 63b / black material layer 63a are sequentially laminated from the test substrate holding glass 12 side. It is configured as.

<Execution test example 3>
Except that the test substrate shown in FIG. 7-3 was used, the test substrate was tested for thermal radiation and thermal uniformity in the same manner as in Test Example 1. As shown in FIG. 7-3, the test substrate of Test Example 3 is provided with a layer having high thermal conductivity and high thermal radiation on the surface of the glass substrate (on the side opposite to the side where the light emitting function part is formed). On the other hand, only the aluminum sheet is stuck on the inner surface. Therefore, the test substrate of Example 3 is composed of a laminate in which the aluminum layer 63b / glass substrate 11 / aluminum layer 63b / black material layer 63a are sequentially laminated from the test substrate holding glass 12 side.

<Comparative Test Example 1>
Except that the test substrate shown in FIG. 7-4 was used, the test substrate was tested for thermal radiation and thermal uniformity in the same manner as in Test Example 1. As a test substrate of Comparative Test Example 3, a single glass substrate 11 was used as shown in FIG.

<Comparative Test Example 2>
Except that the test substrate shown in FIG. 7-5 was used, the test substrate was tested for thermal radiation and thermal uniformity in the same manner as in Test Example 1 described above. In the test substrate of Comparative Test Example 2, as shown in FIG. 7-5, only the aluminum sheet is attached to the surface of the glass substrate 11 on the side where the light emitting function portion is formed. Therefore, the test substrate 15 in the comparative test example 2 is configured by a laminated body in which the aluminum layer 63b / the glass substrate 11 are sequentially laminated in order from the test substrate holding glass 12.

<Evaluation>
FIG. 8 and Table 3 show the verification test results for the above-described Example Tests 1 to 3 and Comparative Test Examples 1 and 2.

  Table 3 shows a list of maximum temperatures and maximum / minimum temperature differences. The maximum temperature is a value indicating the highest temperature for each test substrate, and indicates the temperature at the center of each test substrate. The numerical value in parentheses is a value obtained by subtracting the maximum temperature of Comparative Test Example 1 (ie, 90.0 ° C.) from the maximum temperature of each test substrate. Moreover, the numerical value of the maximum-minimum temperature is a difference between the maximum value and the minimum value in the same test substrate, and is an index of heat uniformity (heat dispersibility).

  As shown in Table 3, it was revealed that all of the test examples 1 to 3 had a lower maximum temperature than the comparative test examples 1 and 2 and released more heat at the central portion showing the maximum temperature. . Further, it was found that Comparative Test Examples 1 and 2 have a larger maximum-minimum temperature difference value, and the temperature difference in the same substrate is larger.

  As shown in FIG. 8, in Comparative Examples 1 and 2, the measurement positions A to C and I to K at the periphery of the test substrate are about 40 to 55 ° C., whereas the measurement position D at the center of the substrate is shown. In ˜H, a remarkable temperature difference of about 80 to 90 ° C. was observed. As described above, it was revealed that the test substrates used in Comparative Test Examples 1 and 2 have low heat uniformity (heat dispersibility).

  On the other hand, regarding the test examples 1 to 3, it became clear that the temperature distribution between the measurement positions A to K was gently distributed between about 70 to 80 ° C. That is, it was revealed that the test substrates provided for the test examples 1 to 3 have high heat uniformity (heat dispersibility).

<Production Example 2> Production of bottom emission type organic EL device A bottom emission type organic EL device was produced by the following method. First, a 200 × 200 mm glass substrate on which a plurality of ITO transparent conductive film patterns and Cr patterns for organic EL elements of 30 × 40 mm size were formed was produced. The ITO transparent conductive film was formed to a film thickness of about 150 nm by sputtering, and Cr was patterned to 200 nm by sputtering.

  Next, by using a suspension of poly (3,4) ethylenedioxythiophene / polystyrene sulfonic acid (by HC Starck, Bytron P TP AI 4083) on a glass substrate with ITO and Cr pattern, a spin coating method is used. The film was formed and dried in an oven at 200 ° C. for 20 minutes to form a hole injection layer having a thickness of 60 nm. Thereafter, unnecessary hole injection layers around the organic EL element were wiped off with a wiper soaked in water.

Next, using a solvent in which cyclohexanone and xylene are mixed in a 1: 1 ratio, a 1.5% by weight solution of a polymer organic light emitting material (Lumation GP1300, manufactured by Summation) is prepared, and spin coating is performed using this solution. By coating on the substrate on which the hole injection layer was formed, a light emitting layer was formed. Thereafter, an unnecessary portion of the light emitting layer in the periphery of the device was wiped off with an organic solvent, followed by vacuum drying (pressure 1 × 10 ⁻⁴ Pa or less, temperature about 170 ° C., heating for 15 minutes).

  Thereafter, the substrate is transferred to a deposition chamber, and after alignment with the cathode mask, the cathode is deposited. For the cathode, Ba metal was heated by a resistance heating method and deposited at a deposition rate of about 2 mm / sec and a film thickness of 50 mm, and Al was deposited at an evaporation rate of about 10 mm / sec and a film thickness of 1000 mm using an electron beam deposition method. . After forming the cathode, it is not exposed to the atmosphere from the vapor deposition chamber, but is transferred to a glove box under an inert atmosphere.

  Next, a glass-sealed substrate (thickness 0.7 mm) on which a material made of a high thermal conductivity material to which black coating was applied was prepared. The high thermal conductivity material with black coating is made of a high thermal conductivity aluminum sheet with high thermal emissivity and a sheet made of an adhesive for bonding to a glass substrate (trade name: manufactured by Kobe Steel) Kobebenets aluminum (KS750), thermal conductivity 230 W / mK, thermal emissivity: 0.86) was used. Adhesion of the high thermal conductivity material coated with black to the glass sealing substrate was performed using a thermosetting resin (Robner Resins, trade name: PX681C / NC), and the adhesion area was a peripheral part. After coating the entire surface, place the glass-sealed substrate in a glove box under an inert atmosphere, align it with the substrate on which the cathode is formed, bond it, hold it in a vacuum, return it to atmospheric pressure, and heat the element The substrate and the sealing substrate were fixed to produce a polymer organic EL device. The used thermosetting resin had a viscosity before curing of 50 mPa · s.

<Production Example 3> Production of Bottom Emission Type Organic EL Element In Production Example 3, the material combination of the element substrate and the sealing substrate in Production Example 2 is opposite. That is, the whole substrate is sealed by using a substrate on which a material made of a high thermal conductivity material coated with black paint is attached to a support substrate, and using a glass substrate as a sealing substrate. Thus, in a so-called top emission type element that extracts light from the sealing substrate side, an element having a uniform surface temperature distribution can be manufactured as in the first embodiment.

It is sectional drawing of the organic EL element of the 1st Embodiment of this invention. It is sectional drawing of the organic EL element of the 2nd Embodiment of this invention. It is sectional drawing which shows the 3rd Embodiment of this invention. It is sectional drawing which shows one modification of the 3rd Embodiment of this invention. It is sectional drawing which shows one modification of the 3rd Embodiment of this invention. It is sectional drawing which shows one modification of the 3rd Embodiment of this invention. It is sectional drawing which shows one modification of the 3rd Embodiment of this invention. It is sectional drawing which shows one modification of the 3rd Embodiment of this invention. It is sectional drawing which shows the 4th Embodiment of this invention. It is a figure which shows the side surface of a verification experiment apparatus. It is a top view which shows the test board | substrate mounted on a verification experiment apparatus, and a measurement position. It is a figure which shows sectional drawing of the test board | substrate provided to the implementation test example 1. FIG. It is a figure which shows sectional drawing of the test board | substrate provided to the implementation test example 2. FIG. It is a figure which shows sectional drawing of the test board | substrate provided to the implementation test example 3. FIG. It is a figure which shows sectional drawing of the test board | substrate provided to the comparative test example 1. FIG. It is a figure which shows sectional drawing of the test board | substrate provided to the comparative test example 2. FIG. It is a figure which shows a verification test result.

Explanation of symbols

1, 2, 3A, 3B, 4A Organic EL element 10 Support substrate 11 Glass substrate 12 Test substrate holding glass 15 Test substrate 20 Light emitting function portion 21 Anode 22 Cathode 23 Multi-layer light emitting portion 23a Red light emitting layer 23b Green light emitting layer 23c Blue light emitting Layers 30, 31 Sealing substrate 40 Adhesion 60, 61 Heat dissipation layer 63 Two-layer structure heat dissipation layer 63 having high thermal conductivity 63a Black material layer 63b Aluminum layer 64 Three-layer structure having high thermal conductivity composed of three layers Heat radiation layer 80 Test stand 81 Hot plate 82 Heat insulation sheet 83 Heat conduction part (heat source, brass)
84 Temperature sensor AK (in Fig. 6) Measurement position

Claims (18)

The anode,
A cathode,
Between the anode and the cathode, a multi-layer light emitting part formed by laminating a plurality of light emitting layers disposed closer to the anode as the light emitting layer having a longer peak wavelength of emitted light;
A support substrate on which a laminate including the anode, the cathode, and the multilayer light emitting unit is mounted;
A sealing substrate disposed opposite to the support substrate and sandwiching the laminate together with the support substrate;
A heat dissipating layer disposed on at least one main surface of the support substrate or at least one main surface of the sealing substrate and having a thermal emissivity of 0.70 or more;
An organic electroluminescence device comprising:   The organic electroluminescent element according to claim 1, wherein the multilayer light-emitting portion includes three layers of a light-emitting layer that emits red light, a light-emitting layer that emits green light, and a light-emitting layer that emits blue light.   The organic electroluminescent element of Claim 1 or 2 whose light emitting layer is a layer containing a luminescent high molecular organic compound.   When the voltage applied between the anode and the cathode is changed, the width of change between the coordinate value x and the coordinate value y in the chromaticity coordinates of the light extracted outside is 0.05 or less, respectively. The organic electroluminescent element according to any one of claims 1 to 3.   The organic electroluminescent element according to any one of claims 1 to 4, wherein the heat emissivity of the heat dissipation layer is 0.85 or more.   The organic electroluminescent element according to claim 1, wherein the heat dissipation layer has a thermal conductivity of 1 W / mK or more.   The organic electroluminescent element according to claim 1, wherein the heat dissipation layer has a thermal conductivity of 200 W / mK or more.   The organic electroluminescent element according to claim 1, wherein the heat dissipation layer includes a black material.   The organic electroluminescence element according to claim 8, wherein the heat dissipation layer has a laminated structure including a high thermal conductivity layer and a black material layer.   The high thermal conductivity layer is formed of an inorganic material selected from the group consisting of aluminum, copper, silver, a ceramic material, and two or more alloys selected from these, or a high thermal conductivity resin. The organic electroluminescent element of description.   The organic electroluminescence element according to any one of claims 1 to 10, wherein the support substrate is a glass substrate, and the heat dissipation layer is provided on at least one main surface of the glass substrate.   The organic electroluminescent element according to claim 11, wherein the heat dissipation layer is provided on a main surface opposite to a main surface on which the laminate of the glass substrate is mounted.   The organic electroluminescent element according to claim 13, wherein the heat dissipation layer is provided on both main surfaces of the glass substrate.   The heat dissipation layer is provided on a main surface opposite to the main surface on which the laminate of the glass substrate is mounted, and a high thermal conductivity layer is provided on the main surface of the glass substrate on the laminate. Item 12. The organic electroluminescence device according to Item 11.   The organic electroluminescent element according to any one of claims 1 to 14, wherein the sealing substrate is a glass substrate, and the heat dissipation layer is provided on at least one main surface of the glass substrate.   A planar light source comprising the organic electroluminescence element according to any one of claims 1 to 15.   An illuminating device provided with the organic electroluminescent element as described in any one of Claims 1-15.   A display apparatus provided with the organic electroluminescent element as described in any one of Claims 1-15.

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