JP2009266832A - Organic el display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an organic EL display which has excellent display quality by suppressing the occurrence of non-illumination dots. <P>SOLUTION: The organic EL display comprises an anode 60 disposed on a substrate, a cathode 64 disposed opposite to the anode 60, an organic layer 62 disposed between the anode 60 and cathode 64 and including a light-emitting layer 62A, a first oxide layer 81 disposed between the organic layer 62 and cathode 64 and having a hole shape or having unevenness on a surface, and a second oxide layer 82 disposed between the first oxide layer 81 and cathode 64 and having a film structure different from that of the first oxide layer 81. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an organic EL display device including an organic electroluminescence (EL) element which is a self-luminous display element.

  With respect to CRT displays, the demand for flat display devices typified by liquid crystal display devices is rapidly increasing by taking advantage of the features of thinness, light weight and low power consumption. Among them, an active matrix type flat display device in which a switch element is provided in each pixel has been used for various displays because it can obtain a good display quality without crosstalk between adjacent pixels. ing.

  In recent years, organic electroluminescence (EL) display devices have been actively developed as flat display devices. Since this organic EL display device is a self-luminous display, it has a wide viewing angle, can be reduced in thickness and weight without the need for a backlight, has low power consumption, and has a high response speed. It has characteristics.

  Because of these features, organic EL display devices are attracting attention as potential candidates for next-generation flat display devices that replace liquid crystal display devices. Such an organic EL display device includes an organic EL element that holds an organic material layer containing an organic compound having a light emitting function between an anode and a cathode as a display element on a support substrate such as glass.

Such an organic EL element has a drawback that the light emission lifetime is short, and various factors can be considered as the cause. According to Patent Document 1, focusing on the fact that the light emission efficiency is lowered due to the influence of oxygen, moisture, etc. from the outside, the cathode has a two-layer structure and includes an alkali metal or an alkaline earth metal and contacts the organic EL layer. A second conductive film including one conductive film and at least one metal selected from the group consisting of Ru (ruthenium), Rh (rhodium), Ir (iridium), Os (osmium), and Re (rhenium) or an oxide thereof; A technique for applying a laminated structure with a film is disclosed. With such a configuration, oxidation of alkali metal or alkaline earth metal is prevented, and generation of dark spots is suppressed.
JP 2002-75661 A

  When a foreign substance is mixed in the organic material layer, current leakage may occur between the anode and the cathode, and the organic EL element may be darkened.

  The present invention has been made in view of the above-described problems, and an object thereof is to provide an organic EL display device that suppresses the occurrence of dark spots and has good display quality.

An organic EL display device according to an aspect of the present invention includes:
An anode disposed on a substrate;
A cathode disposed opposite the anode;
An organic layer disposed between the anode and the cathode and including a light emitting layer;
A first oxide layer disposed between the organic material layer and the cathode and having a porous shape or an uneven shape on the surface;
A second oxide layer disposed between the first oxide layer and the cathode and having a film structure different from that of the first oxide layer;
It is provided with.

  According to the present invention, it is possible to provide an organic EL display device that suppresses the occurrence of dark spots and has good display quality.

  A display device according to an embodiment of the present invention will be described below with reference to the drawings. In this embodiment, a self-luminous display device such as an organic EL (electroluminescence) display device will be described as an example of the display device.

  As shown in FIG. 1, the organic EL display device 1 includes an array substrate 100 having a substantially rectangular active area 102 for displaying an image. The active area 102 is composed of a plurality of pixels PX arranged in a matrix. FIG. 1 shows a color display type organic EL display device 1 as an example. The active area 102 includes pixels that emit light of a plurality of colors, for example, a red pixel PXR, a green pixel PXG corresponding to three primary colors, And it is comprised by the blue pixel PXB.

  At least the active area 102 of the array substrate 100 is sealed with a sealing body 200. That is, the array substrate 100 and the sealing body 200 are bonded together by the sealing material 300 arranged in a frame shape so as to surround the active area 102. The sealing material 300 may be a photosensitive resin (for example, an ultraviolet curable resin) or a frit.

  In this embodiment, the organic EL display device 1 employs an active matrix driving method, and each pixel PX (R, G, B) is driven and controlled by the pixel circuit 10 and the pixel circuit 10. A display element 40 is provided. Note that the pixel circuit 10 illustrated in FIG. 1 is an example, and it is needless to say that a pixel circuit having another configuration may be applied.

  The display element 40 includes an organic EL element 40 (R, G, B) that is a self-luminous display element. That is, the red pixel PXR includes an organic EL element 40R that mainly emits light corresponding to the red wavelength. The green pixel PXG includes an organic EL element 40G that mainly emits light corresponding to the green wavelength. The blue pixel PXB includes an organic EL element 40B that mainly emits light corresponding to the blue wavelength.

  In the example illustrated in FIG. 1, the pixel circuit 10 includes a driving transistor DRT, a switching transistor SW, a storage capacitor element Cs, and the like.

  The drive transistor DRT and the organic EL element 40 are connected in series in this order between the first power supply terminal ND1 and the second power supply terminal ND2. In this example, the power supply terminal ND1 is a high potential power supply terminal, and the power supply terminal ND2 is a low potential power supply terminal. The first power supply terminal ND1 is connected to the high potential power supply line P1. The second power supply terminal ND2 is connected to the low potential power supply line P2.

  The gate of the switching transistor SW is connected to the scanning line SL. The source of the switching transistor SW is connected to the video signal line DL. The drain of the switching transistor SW is connected to the gate of the drive transistor DRT. The storage capacitor element Cs is connected between the gate of the drive transistor DRT and the first power supply terminal ND1.

  These drive transistor DRT and switching transistor SW are constituted by thin film transistors having a semiconductor layer made of polycrystalline silicon.

  In the case of such a circuit configuration, the switching transistor SW is turned on based on the ON signal supplied from the scanning line SL, and the driving transistor DRT is driven by the voltage supplied to the video signal line DL. As a result, a current corresponding to the voltage of the video signal line DL flows through the drive transistor DRT and the organic EL element 40. Thereby, the organic EL element 40 emits light with a predetermined luminance.

  Even when the switching transistor SW is turned off, the voltage is held in the storage capacitor element Cs, and therefore, until one frame later, the switching transistor SW is turned on again and a new data voltage is supplied from the video signal line DL. The EL element 40 emits light as it is.

  Each scanning line SL extends along the row direction X of the pixels PX, and is arranged in parallel in the column direction Y of the pixels PX. Each video signal line DL extends along the column direction Y and is arranged in parallel in the row direction X. These scanning lines SL and video signal lines DL are drawn outside the active area 102.

  The array substrate 100 includes a drive circuit DRC arranged around the active area 102. That is, the drive circuit DRC outputs a signal necessary for drive control of the organic EL element 40, and is configured by the scanning line drive circuit YDR and the video signal line drive circuit XDR. Such a drive circuit DRC includes a thin film transistor including a semiconductor layer made of polycrystalline silicon. The scanning line driving circuit YDR and the video signal line driving circuit XDR employ a configuration including complementary circuits composed of, for example, an n-channel thin film transistor and a p-channel thin film transistor.

  The scanning line driving circuit YDR is connected to all the scanning lines SL outside the active area. The video signal line drive circuit XDR is connected to all the video signal lines DL outside the active area. In these drive circuits DRC, the scan line drive circuit YDR supplies a scan signal to each of the scan lines SL based on a video signal input from the outside, and the video signal line drive circuit XDR receives each of the video signal lines DL. Video signal is supplied. Thereby, in each pixel PX, the pixel circuit 10 is driven and controlled, and the organic EL element 40 is energized to cause the organic EL element 40 to emit light.

  The various organic EL elements 40 (R, G, B) have basically the same configuration, and are disposed on the wiring substrate 120 as shown in FIG. The wiring substrate 120 includes an insulating layer such as an undercoat layer, a gate insulating film, an interlayer insulating film, and an organic insulating film on an insulating support substrate such as a glass substrate or a plastic sheet, as well as a switching transistor SW, The driving transistor DRT, the storage capacitor element Cs, various wirings (scanning lines, video signal lines, power supply lines, etc.), a driving circuit DRC, and the like are configured.

  The organic EL element 40 is disposed on the wiring substrate 120 so as to face the first electrode 60 (that is, disposed closer to the sealing substrate 200 than the first electrode 60), and has a plurality of colors. The second electrode 64 is common to the pixel PX, and the organic layer 62 is disposed between the first electrode 60 and the second electrode 64.

  A more specific configuration example of the organic EL element 40 will be described. The first electrode 60 is arranged in an independent island shape for each color pixel PX on the wiring substrate 120 and functions as an anode. The first electrode 60 is electrically connected to the drive transistor DRT. The first electrode 60 includes a transmissive layer formed using a light transmissive conductive material such as indium tin oxide (ITO), and a light reflective conductive material such as aluminum (Al). The reflective layer formed using may be laminated, or may be configured as a single reflective layer or a single transmissive layer.

  The organic material layer 62 is disposed on the first electrode 60 and includes at least the light emitting layer 62A. The organic material layer 62 can include functional layers other than the light emitting layer 62A, and can include functional layers such as a hole injection layer, a hole transport layer, a blocking layer, an electron transport layer, and a buffer layer. The organic material layer 62 may be composed of a single layer composed of a plurality of functional layers, or may have a multilayer structure in which the functional layers are laminated. In the organic layer 62, the light emitting layer 62A may be an organic material, and layers other than the light emitting layer 62A may be an inorganic material or an organic material.

  The organic material layer 62 may include a common layer common to a plurality of color pixels. In the example illustrated in FIG. 2, the common layers are disposed on the first electrode 60 side and the second electrode 64 side of the light emitting layer 62A, respectively. Has been. One common layer 62H includes a hole injection layer, a hole transport layer, and the like, and the other common layer 62E includes an electron injection layer, an electron transport layer, and the like.

  The light emitting layer 62A is formed of an organic compound having a light emitting function that emits red, green, or blue light. The light emitting layer 62A of the organic EL element 40R of the red pixel PXR includes at least an organic compound that emits red light, and the light emitting layer 62A of the organic EL element 40G of the green pixel PXG includes at least an organic compound that emits green light. The light emitting layer 62A of the organic EL element 40B contains an organic compound that emits at least blue light. Further, the light emitting layer 62A disposed in each color pixel PX (R, G, B) may be configured as a stacked body in which organic compounds that emit light in red, green, and blue are stacked, or a mixture in which these are mixed. It may be configured as a layer.

  Further, the organic layer 62 may include a thin film formed of a polymer material. Such a thin film can be formed by a selective coating method such as an inkjet method. Further, the organic layer 62 may include a thin film formed of a low molecular material. Such a thin film can be formed by a technique such as mask vapor deposition.

  The second electrode 64 is disposed on the organic layer 62 of each color pixel PX and functions as a cathode. The second electrode 64 has a structure in which a transflective layer made of a mixture of silver (Ag) and magnesium (Mg) and the like, and a transmissive layer formed using a light-transmitting conductive material such as ITO are laminated. It may be configured as a single semi-transmissive layer or a single transmissive layer.

  In addition, the array substrate 100 includes a partition wall 70 that separates at least adjacent color pixels PX (R, G, B) in the active area 102. The partition wall 70 is disposed, for example, so as to cover the periphery of each first electrode 60, and is formed in a lattice shape or a stripe shape in the active area 102. Such a partition 70 is formed by patterning a resin material, for example. The partition wall 70 is covered with the second electrode 64.

  By the way, in this embodiment, the organic EL element 40 includes an oxide layer 80 having a laminated structure of at least two layers between the organic layer 62 and the second electrode 64. That is, the oxide layer 80 is disposed between the first oxide layer 81 disposed between the organic material layer 62 and the second electrode 64, and between the first oxide layer 81 and the second electrode 64. A second oxide layer 82.

  The first oxide layer 81 is laminated on the organic material layer 62 and has a porous shape or an uneven shape on the surface (that is, a shape in which the film thickness is locally reduced). The second oxide layer 82 is stacked on the first oxide layer 81, has a different film structure from the first oxide layer 81, and has a flat shape (that is, the number of voids in the layer is extremely small and substantially uniform). Shape having a sufficient film thickness). Thereby, it is possible to reduce the dark spot caused by the foreign matter mixed in the organic layer 62.

  That is, when the oxide layer 80 is formed between the organic material layer 62 and the second electrode 64, the leakage current between the electrodes due to the foreign matter can be shielded, and an effect of reducing the dark spot can be obtained. However, some metals used to form the oxide layer 80 shrink in volume during oxidation depending on the type. For this reason, the formed oxide layer 80 has a perforated shape with voids formed therein, or a shape having irregularities on the surface, and the thickness of the oxide layer 80 is locally reduced.

  When such an oxide layer 80 is used as a single layer, the leakage current shielding performance becomes insufficient, and the effect of reducing the dark spot is lowered. For this reason, the thickness of the oxide layer 80 needs to be designed to be thick overall. As described above, when the single oxide layer 80 having a large thickness is disposed, the electron injection from the second electrode 64 to the organic material layer 62 is hindered, and the voltage increases or the light emission efficiency decreases. Problem arises.

  In response to such a problem, according to the present embodiment, the oxide layer 80 is formed by laminating a porous or uneven first oxide layer 81 and a flat second oxide layer 82. It is configured. For this reason, in order to reduce the leakage current with the first oxide layer 81 alone, a thick film thickness of about 10 nm is required, whereas a flat second oxide layer 82 is formed on the first oxide layer 81. By laminating, it is possible to obtain a dark spot reduction effect even if the thickness of the entire oxide layer 80 is reduced.

  For example, even when the second oxide layer 82 having a thickness of about 2 nm is stacked on the first oxide layer 81 having a thickness as thin as about 5 nm, a sufficient effect of reducing the dark spot can be obtained. It was. Note that the film thickness here corresponds to the distance from the surface of the organic material layer 62 to the second oxide layer 82 for the first oxide layer 81. When the surface has irregularities, it corresponds to the thickness up to the surface of the convex part. The film thickness of the second oxide layer 82 corresponds to the distance from the first oxide layer 81 to the second electrode 64.

  As described above, it is possible to reduce the dark spots caused by the foreign matters and to reduce the thickness of the entire organic EL element 40. For this reason, it is possible to reduce the thickness of the device, reduce the material used, reduce the manufacturing time, and reduce the manufacturing cost. In addition, since the distance between the organic material layer 62 and the second electrode 64 can be shortened, electron injection is promoted, and the drive voltage required for light emission can be reduced and the light emission efficiency can be improved.

  As a specific configuration example of the organic EL element 40, for example, as shown in FIG. 3, a hole injection layer HI, a hole transport layer HT, a light emitting layer 62A, and an electron transport layer are sequentially formed on the first electrode 60. An organic material layer 62 in which ET is laminated is provided, an electron injection layer EI is provided on the organic material layer 62, and a first oxide layer 81 and a second oxide layer 82 are sequentially laminated on the electron injection layer EI. A configuration in which the oxide layer 80 is provided and the second electrode 64 is provided on the second oxide layer 82 is applicable.

  As in the example shown in FIG. 4, the organic EL element 40 includes an organic layer 62 on the first electrode 60 as in the example shown in FIG. 3, and further, electron transport in the organic layer 62. A first oxide layer 81 formed of an oxide material having an electron injecting property is disposed on the layer ET, a second oxide layer is stacked on the first oxide layer 81, and a second oxidation layer is further formed. A configuration in which the second electrode 64 is provided on the physical layer 82 is also applicable.

  In the configuration example shown in FIG. 4, since the first oxide layer 81 also has the function of the electron injection layer EI, it is not necessary to separately provide the electron injection layer EI, and the process is simplified. In addition, the thickness of the entire organic EL element can be further reduced.

  The first oxide layer 81 and the second oxide layer 82 described above are formed of a material that satisfies the following conditions. That is, when the molecular weight of the metal X is w, the density of the metal X is d, the molecular weight of the oxide of the metal X is W, and the density of the oxide of the metal X is D, the first oxide layer 81 is Wd / Dw. Is formed of a material smaller than 1, and the second oxide layer 82 is formed of a material whose Wd / Dw is larger than 1.

  A material having a Wd / Dw of less than 1 has a high volumetric shrinkage rate during oxidation. Therefore, an oxide layer formed using such a material is perforated or uneven, and the film thickness locally decreases. On the other hand, a material having a Wd / Dw greater than 1 has a very small volume shrinkage rate (or hardly occurs) during oxidation. Therefore, an oxide layer formed using such a material becomes flat and has a substantially uniform film thickness. It becomes.

  The organic EL film thickness and the structure of the oxide layer in this example can be measured by, for example, observing a cross section with a transmission electron microscope (TEM), and an energy dispersive X-ray analyzer (EDS). Elemental analysis is possible with the analysis.

  By combining the second oxide layer 82 as described above, a material for forming the first oxide layer 81 even if the thickness of the second oxide layer 82 is smaller than that of the first oxide layer 81. As a result, the selection range of the display has been expanded, and the optimum design as a display is facilitated in terms of driving voltage and light emission efficiency.

For example, as a material for forming the first oxide layer 81, a material such as an alkali metal that causes volume shrinkage during oxidation as shown below can be used. For example, as a material having Wd / Dw smaller than 1, lithium (Li) (Wd / Dw = 0.6), sodium (Na) (Wd / Dw = 0.3), potassium (K) (Wd / Dw = 0) .51), calcium (Ca) (Wd / Dw = 0.78), strontium (Sr) (Wd / Dw = 0.69), cesium (Cs) (Wd / Dw = 0.42), barium (Ba) (Wd / Dw = 0.78). The first oxide layer 81 is formed of any one of these oxide materials. Note that lithium or the like may be selected in the case where the first oxide layer 81 having the function of an electron injection layer is applied. That is, since the first oxide layer 81 formed of lithium oxide (LiO ₂ ) also has an electron injection function, it is not necessary to dispose an electron injection layer separately.

  On the other hand, as a material for forming the second oxide layer 82, for example, silicon (Si) (Wd / Dw = 2.04), chrome (Cr) (Wd / Dw = 3.92), manganese (Mn) (Wd / Dw = 2.07), copper (Cu) (Wd / Dw = 1.7), and the like. The second oxide layer 82 is formed of any one of these oxide materials.

  In such an organic EL device 40, the thinner the organic layer 62, the greater the effect of reducing the dark spot by forming the oxide layer 80. Specifically, the effect is particularly great when the thickness of the organic layer 62 is in the range of 40 nm or more and 120 nm or less. If the film thickness of the organic layer 62 is less than 40 nm, the optical interference film thickness design is not suitable and the panel brightness may be lowered. Further, when the film thickness of the organic material layer 62 is larger than 120 nm, foreign matter is easily covered by the insulating property of the organic material layer itself, so that the advantage of forming the oxide layer 80 becomes relatively small.

  Next, more specific examples will be described.

  First, the first electrode 60 is formed on the wiring board 120. That is, the first electrode 60 having a transparent layer made of ITO on the surface is formed for each pixel by film formation and patterning of a conductive material.

  Thereafter, amorphous carbon as the hole injection layer HI and αNPD as the hole transport layer HT are formed on the transmission layer of the first electrode 60 by vapor deposition. Then, for the red pixel, the green pixel, and the blue pixel, using a fine mask, the Red light emitting layer material (host: Alq3, dopant: DCM), the Green light emitting layer material (host: Alq, dopant: coumarin), Blue light emission. Layer materials (host: BH120, dopant: BD-102) are vapor-deposited to form respective light emitting layers 62A. Then, the electron transport layer ET is formed on each of the light emitting layers 62A. The total thickness of the organic material layer 62 in which the hole injection layer HI, the hole transport layer HT, the light emitting layer 62A, and the electron transport layer ET are stacked is 50 nm.

  Thereafter, lithium fluoride (LiF) is formed with a thickness of 1 nm as the electron injection layer EI on the electron transport layer ET.

  Then, after forming magnesium (Mg) (Wd / Dw = 0.84) with a film thickness of 5 nm on the electron injection layer EI, it was left in an oxygen atmosphere at an oxygen partial pressure of 0.5 Pa, A first oxide layer 81 that is an oxide layer of magnesium is formed. Furthermore, after forming aluminum (Al) (Wd / Dw = 1.28) with a film thickness of 2 nm on the first oxide layer 81, it is left in an oxygen atmosphere at an oxygen partial pressure of 0.5 Pa. Then, the second oxide layer 82 which is an aluminum oxide layer is formed.

  Subsequently, magnesium and silver are vapor-deposited on the second oxide layer 82 to form a second electrode 64 that is a semi-transmissive layer having a thickness of 25 nm. Furthermore, sealing with the sealing body 200 was implemented to configure an organic EL display device.

  When the formed magnesium oxide layer 81 was observed with a TEM, it had pores, but the oxide layer 82 after the formation of the aluminum oxide layer 82 was flat.

Next, the number of dark spots of the organic EL display device and the drive voltage at a current density of 10 mA / cm ² were measured. The diagonal dimension of the active area of the organic EL display device was 2 inches. Further, as a comparative example, a configuration without the first oxide layer and the second oxide layer is referred to as Comparative Example 1, and a configuration in which only the first oxide layer is formed with a film thickness of 7 nm is referred to as Comparative Example 2. A configuration in which only two oxide layers were formed with a thickness of 7 nm was defined as Comparative Example 3. The measurement results are shown in FIG.

  In the example, it was confirmed that the drive voltage did not increase significantly, and that the drive voltage was equivalent to that of Comparative Example 1. Moreover, in the Example, the effect which a dark spot reduces significantly with respect to the comparative example 1 (20-> 5) was acquired.

  On the other hand, in Comparative Example 2, the driving voltage was the same as that in Comparative Example 1, but since the first oxide layer was porous, the number of dark spots was 10 and the effect of reducing the dark spots was small. In Comparative Example 3, the number of dark spots was the same level as in the example, but the second oxide layer was thick, and the drive voltage was worsened by 0.7 V compared to Comparative Example 1, which is inferior to the example. It was a result.

  As described above, according to the present embodiment, the first oxide layer and the flat second oxide layer having a porous shape or an uneven shape on the surface between the organic material layer and the second electrode (cathode) are provided. By forming these two types of oxide films, the leakage current between the first electrode (anode) and the second electrode (cathode) can be effectively suppressed even with an oxide layer having a small thickness. As a result, it is possible to achieve high efficiency and low voltage while having a dark spot reduction effect.

  Note that the present invention is not limited to the above-described embodiment as it is, and can be embodied by modifying the constituent elements without departing from the spirit of the invention in the stage of implementation. Further, various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the embodiment. For example, some components may be deleted from all the components shown in the embodiment. Furthermore, you may combine suitably the component covering different embodiment.

  A configuration in which a current signal is written as a video signal in the pixel circuit 10 may be employed, or a configuration in which a voltage signal is written as a video signal may be employed. The thin film transistors constituting the pixel circuit 10 and the drive circuit DRC may be p-channel thin film transistors or n-channel thin film transistors.

FIG. 1 is a diagram schematically showing a configuration of an organic EL display device according to an embodiment of the present invention. FIG. 2 is a cross-sectional view schematically showing a structure when the organic EL display device shown in FIG. 1 is cut. FIG. 3 is a diagram schematically illustrating a configuration example of the organic EL element according to the present embodiment. FIG. 4 is a diagram schematically showing another configuration example of the organic EL element according to this embodiment. FIG. 5 is a diagram illustrating the measurement results of the number of dark spots and the drive voltage for each of the example and the comparative example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Organic EL display device PX (R, G, B) ... Pixel SL ... Scanning line DL ... Video signal line DRC ... Drive circuit YDR ... Scan line drive circuit XDR ... Video signal line drive circuit 10 ... Pixel circuit DRT ... Drive transistor SW: Switching transistor 40: Organic EL element (display element)
60 ... 1st electrode (anode) 62 ... Organic substance layer 62A ... Light emitting layer 64 ... 2nd electrode (cathode)
HI ... hole injection layer HT ... hole transport layer ET ... electron transport layer EI ... electron injection layer 70 ... partition wall 80 ... oxide layer 81 ... first oxide layer 82 ... second oxide layer 100 ... array substrate 102 ... active area DESCRIPTION OF SYMBOLS 120 ... Wiring board 200 ... Sealing body 300 ... Sealing material

Claims (8)

An anode disposed on a substrate;
A cathode disposed opposite the anode;
An organic layer disposed between the anode and the cathode and including a light emitting layer;
A first oxide layer disposed between the organic material layer and the cathode and having a porous shape or an uneven shape on the surface;
A second oxide layer disposed between the first oxide layer and the cathode and having a film structure different from that of the first oxide layer;
An organic EL display device comprising:   When the molecular weight of the metal X is w, the density of the metal X is d, the molecular weight of the oxide of the metal X is W, and the density of the oxide of the metal X is D, the first oxide layer has a Wd / Dw of 1. 2. The organic EL display device according to claim 1, wherein the organic EL display device is formed of a smaller material, and the second oxide layer is formed of a material having Wd / Dw of greater than 1. 3.   The organic EL display device according to claim 1, further comprising an electron injection layer between the organic material layer and the first oxide layer. The organic layer is a laminate in which a hole injection layer, a hole transport layer, a light emitting layer, and an electron transport layer are stacked in order from the anode side,
The organic EL display device according to claim 1, wherein the first oxide layer is formed of an oxide material having an electron injecting property and is stacked on the electron transporting layer.   The organic EL display device according to claim 1, wherein a film thickness of the first oxide layer is larger than a film thickness of the second oxide layer.   2. The organic EL display device according to claim 1, wherein the thickness of the organic layer is 40 nm or more and 120 nm or less.   The first oxide layer is made of an oxide material of lithium (Li), sodium (Na), potassium (K), calcium (Ca), strontium (Sr), cesium (Cs), or barium (Ba). The organic EL display device according to claim 1, wherein the organic EL display device is formed.   2. The organic material according to claim 1, wherein the second oxide layer is formed of an oxide material of silicon (Si), chromium (Cr), manganese (Mn), or copper (Cu). EL display device.

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