JP2007234259A - Organic EL display device - Google Patents

Abstract

A low power consumption organic EL display device with improved hole injection characteristics and high light emission efficiency is provided.
In an organic EL display device in which an organic EL element formed by sequentially laminating an organic film and a metal film on an ITO electrode is arranged in a matrix, the ITO electrode is disposed in the vicinity of the boundary between the ITO electrode and the organic layer. A structure using an ITO electrode in which the distribution of the oxygen content in the electrode in the depth direction increases from the inside of the ITO electrode toward the organic film is used.
[Selection] Figure 2

Description

  The present invention relates to an organic EL display device.

  Since the ITO electrode surface of the organic EL display device is required to be smooth, it is often formed at a low temperature. The ITO electrode formed at a low temperature contains advantageous oxygen and moisture in addition to oxygen and unbonded In and Sn. Further, the surface of the ITO electrode that has undergone the steps such as the bank formation step tends to be oxygen deficient due to reduction or the like. In fact, In released from the light emitting defect portion is observed.

  Therefore, surface treatment of the ITO electrode (UV treatment, oxygen plasma treatment, etc.) is essential. Cleaning the ITO surface and increasing the work function are said to be the effect of surface treatment. However, even if the surface treatment is performed under the same conditions, the results obtained vary, and it has not been known how these surface treatments should change the quality of the ITO electrode. This is a problem in extending the life of organic EL display devices and building mass production lines.

In the bottom emission type organic EL display device, an ITO electrode which is an n-type semiconductor using electrons generated by replacing oxygen vacancies or Sn ⁴⁺ with In ³⁺ is used as a hole injection electrode. The inventor is thought to be able to inject holes because the work function can be increased, but has wondered that there is an adverse effect of electrons which are majority carriers.

In order to improve the characteristics of the organic EL display device, Patent Document 1 discloses that a p-type semiconductor is inserted between the ITO electrode and the organic layer. Patent Document 2 discloses an ITO electrode structure in which two ITO electrodes having different oxygen contents are formed. This structure is intended to use an outer ITO electrode having a high oxygen content and a high resistance as a protective film. Further, with regard to the composition of the ITO electrode, Patent Document 3 and Patent Document 4 are disclosed in which attention is paid to In and Sn. Furthermore, Patent Documents 5 and 6 describe that surface treatment methods having an oxidizing effect (oxygen plasma treatment, UV / O ₃ treatment, ozone treatment, etc.) are used to clean (clean) the ITO electrode and increase the work function. Has been.
JP 2002-352964 A JP 200431242 A JP 2002-170666 A JP 2002-170431 A JP 2000-311869 A JP 2001-28296 A

  In the above known example, the state of the ITO electrode at the interface of the organic film is not mentioned, and it is not possible to cope with the deterioration of the light emission characteristics and the increase of the driving voltage due to the deterioration of the work function with the lapse of time. Since the ITO electrode surface of the organic EL display device is required to be smooth, it is often formed at a low temperature. Further, the surface of the ITO electrode that has undergone the steps such as the bank formation step tends to be oxygen deficient due to reduction or the like. In fact, In released from the light emitting defect portion is observed. For this reason, the above prior art is not taken into consideration for these problems in which the defect of the ITO electrode increases, the work function is lowered, and the light emission characteristics are likely to deteriorate.

When the work function is increased by surface treatment (oxygen plasma treatment or UV / O ₃ treatment) of the ITO electrode, the inventor increases the oxidation degree of the ITO electrode, decreases the carrier (electron) density, and increases the resistance. . However, the mobility increases because the number of ion scattering centers decreases.

  An object of the present invention is to provide an organic EL display device with improved hole injection characteristics, improved luminous efficiency, and low power consumption.

  Another object of the present invention is to reduce the defects on the ITO surface and to contribute to the improvement of yield by improving the in-plane distribution.

  Another object of the present invention is to suppress the change over time of the interface between the ITO electrode having a high work function and the organic film and to realize a long life of the organic EL display device.

  In order to achieve the above object, in one of the representative means of the present invention, in an organic EL display device in which organic EL elements formed by sequentially laminating an organic film and a metal film on an ITO electrode are arranged in a matrix, There is one using an ITO electrode in which the depth distribution of the oxygen content in the ITO electrode in the vicinity of the boundary between the ITO electrode and the organic layer increases from the inside of the ITO electrode toward the organic film.

  According to the present invention, hole injection characteristics and light emission efficiency of an organic EL display device are improved, and low power consumption is realized.

  An example of an organic EL display device to which the present invention is applied is shown below.

  FIG. 1 is a cross-sectional view of a bottom emission type organic EL display device (OLED) illustrating Example 1 of the present invention. This organic EL display device includes a glass substrate 110, a TFT circuit 120 formed on the glass substrate 110, an insulating film formed on the TFT circuit 120, and an ITO connected to the TFT circuit formed on the insulating film. The insulating film 3 that is an insulating partition wall formed on the ITO electrode 2 called the bank and has an opening on the ITO electrode 2 called the bank, and the ITO electrode 2 and the insulating film 2 exposed through the opening of the insulating film 3 The organic layer 4 (hole injection layer 41, hole transport layer 42, light emitting layer 43, electron transport layer 44) formed on the upper layer is formed on the organic layer 4.

  Hereinafter, it is preferable to distribute the oxygen content of the ITO electrode 2 from the interface A between the insulating layer 1 and the ITO electrode 2 toward the interface B between the ITO electrode 2 and the organic EL layer 4 (hole injection layer 41). Or explain.

FIG. 2 shows the depth direction distribution of the oxygen concentration in the ITO electrode 2 (ITO electrode), which is a feature of the present invention.
A portion Y in the ITO electrode indicates a region having a high carrier (electron) density and a low resistance. In this region, electrons generated by substituting oxygen vacancies or Sn ⁴⁺ sites with In ³⁺ are used as majority carriers, and have an n-type semiconductor property.

In FIG. 2, a location indicated by X indicates a region where the oxygen concentration is higher than that of the Y region. In this region, since the carrier density is low, the resistance is higher than that in the Y region. However, the mobility and work function of the ITO electrode are rather increased. Desirably, the oxygen concentration of the ITO electrode at the interface B should be greater than or equal to the stoichiometric composition. The oxygen concentration in the stoichiometric composition refers to the concentration when the ITO electrode is entirely composed of In ₂ O ₃ and SnO ₂ .

  The depth d indicates the depth from the location X interface B (which indicates the interface between the ITO electrode 2 and the organic layer 4).

  By applying the present invention, the oxygen concentration increases toward the interface B at the location indicated by X above.

  The depth d needs to be 1 nm or more in order to reduce the influence of oxygen diffusion from the interface B to the inside and the mutual diffusion between the ITO electrode 2 and the organic film 4.

  Further, since the ITO electrode 2 is used as a wiring or an electrode, it is necessary to provide a low resistance region indicated by Y. Therefore, it is preferable to set the depth d to 10 nm or less in view of the thickness (50 to 200 nm) of the ITO electrode, its low efficiency, and the formation method of the X region having a high oxygen concentration.

  In FIG. 2A, an X region is provided by diffusing oxygen in a film in which the oxygen concentration of the ITO electrode tends to decrease at the interface B due to damage or the like received in the manufacturing process. The oxygen concentration distribution is increased toward the interface B. This is seen when the present invention is applied to an ITO electrode on which a Si-based insulating film is formed in a reducing atmosphere.

  FIG. 2B shows the case where the present invention is applied to an ITO electrode in a case where the damage received in the manufacturing process is reduced. This is desirable. In the conventional manufacturing process of OLED elements, oxygen plasma treatment and UV treatment are performed for the purpose of cleaning the ITO surface and increasing the work function. However, it is not performed to form a layer having a high resistance and a high work function by increasing oxygen to the inside of the ITO electrode as in the present invention. Therefore, the part with high work function is limited to the surface (interface B), and in the case of the damaged ITO electrode as shown in (A), In and Sn free from oxygen exist on the surface. The surface treatment effect often shows in-plane variation. These cause deterioration of characteristics and lifetime of the OLED element.

  From the above, according to the present invention, the effects shown in FIG. 3 and FIG. 4 can be obtained, and as a result, the present invention contributes to improvement of OLED characteristics such as current efficiency and longer life.

  FIG. 3 is a diagram showing a graph showing the deterioration with time of the work function of the ITO electrode to which the present invention is applied and the conventional ITO electrode. In any case, the UV treatment was performed and the work function according to the elapsed time after the treatment was shown. The work function of the conventional ITO electrode decreased with time, and after 30 minutes, became almost the same as before UV treatment. On the other hand, in the case of the ITO electrode according to the present invention, the decrease in work function is small. Although not shown, the inventors have confirmed that a value of about 5.4 eV is exhibited even after about one month.

  Possible reasons for the work function to decrease over time are surface contamination and oxygen diffusion into the interior, but this is not well understood. For any reason, the ITO electrode according to the present invention has a low work function decrease rate. In addition, the ITO electrode according to the present invention exhibits a higher work function than the conventional ITO electrode. This is probably because the degree of oxidation is increased.

  In the low molecular OLED, the organic film used for the hole injection layer 41 has an ionization potential (work function) of about 5.2 eV. For this reason, an electrode having a work function lower than this value has a poor hole injection characteristic, which is one of the causes of a decrease in luminous efficiency and an increase in driving voltage.

  From the above, the ITO electrode according to the present invention can contribute to the improvement of OLED characteristics such as luminous efficiency and the extension of the lifetime.

Photoelectron spectrum measured by an atmospheric photoelectron spectrometer (manufactured by Riken Keiki, model: AC-2).
The vertical axis (Y axis) shows the nth power of the photoelectron yield Y (number of photoelectrons popping out), and the horizontal axis (X axis) shows the energy (excitation energy) of the irradiation light. The value of n with which the photoelectron spectrum can be linearly approximated is 0.5 in the case of metal. The work function of the metal sample can be obtained from the threshold energy of the photoelectron yield.

  FIG. 4A shows data for an ITO electrode according to the present invention, and FIG. 4B shows data for a conventional ITO electrode subjected to oxygen plasma treatment or UV treatment. In the case of a conventional ITO electrode, as shown in FIG. 4B, two regions (B1, B2) that can be linearly approximated are often seen. One case where the data shown in FIG. 4B is obtained is when the properties are different between the surface layer and the inside. That is, this is a case where the work function of the surface layer subjected to oxygen plasma treatment or UV treatment is high and the work function inside the ITO is small. When the organic film 41 (OLED layer) is laminated on the ITO electrode to form an OLED element, the OLED characteristics deteriorate and the driving voltage increases. This may be caused by a decrease in the oxygen concentration of the ITO electrode at the interface B due to oxygen diffusion into the bulk or the like, or a portion corresponding to B2 due to mutual diffusion between the ITO electrode 2 and the organic film 4, ie, the work function of ITO. It is conceivable that the large surface layer disappears, and this lowers the work function of the ITO electrode surface in contact with the organic film.

  Another case in which the data shown in FIG. 4B is obtained is a case where the ITO electrode surface is composed of a high work function portion and a low work function portion. That is, this is a case where a portion having a high oxygen concentration and a high work function and a portion having a low oxygen concentration and a low work function are distributed on the surface of the ITO electrode. This is likely to occur when the ITO electrode 2 is damaged and oxygen deficiency occurs. Also in this case, when the OLED element is formed by laminating the organic film 41 (OLED layer) thereon, the OLED characteristic is deteriorated and the driving voltage is increased due to the existence of a portion having a small work function.

  On the other hand, according to the ITO electrode of the present invention, since the film has a high work function from the surface to the deep part, even when the organic film 41 (OLED layer) is formed thereon, oxygen at the interface B due to oxygen diffusion is used. The disappearance of the surface layer of ITO having a high work function due to concentration reduction and mutual diffusion hardly occurs. In addition, since the oxygen concentration is increased from the surface of the ITO electrode to the inside, it is possible to prevent the presence of oxygen deficient portions on the surface of the ITO electrode at the interface with the organic film 4. For this reason, it is possible to suppress deterioration in characteristics (such as a decrease in luminance) of the OLED element and increase in driving voltage.

  As described above, according to the present invention, it is possible to obtain a long-life OLED element having excellent OLED characteristics as compared with the conventional art.

  FIG. 5 shows a process flow chart of an example of a method for manufacturing an OLED element using an ITO electrode according to the present invention.

(5A) Formation of ITO electrode on TFT circuit substrate 100 An ITO electrode is formed on the TFT circuit substrate on which the drive circuit is formed by a known sputtering method. The film thickness may be determined according to the design, but is often set between 50 and 200 nm. In this case, the film forming conditions are adjusted so that the surface becomes flat, and unreacted oxygen and moisture are rapidly increased. One of the points is to occlude the unreacted oxygen and moisture.

(5B) Formation of ITO electrode pattern 2 The ITO electrode pattern 2 is formed by processing the ITO electrode using a known photoetching method. An ITO electrode having a flat surface is often amorphous, has poor chemical resistance, and is susceptible to damage. Therefore, conditions are determined so that damage is minimized.

(5C) Heat treatment of ITO electrode pattern 2 The substrate on which the ITO pattern 2 is formed is subjected to heat treatment. This reduces the resistance of the ITO electrode. FIG. 6 shows the relationship between the heat treatment temperature and the resistance value. It can be seen that the lowest resistance value is exhibited at a temperature of 200 to 250 ° C. This reflects a reaction occurring in the ITO electrode and an increase in carrier density (electrons). The reaction in the ITO includes a reaction of unreacted oxygen or water with low indium oxide or low tin oxide, and the degree of oxidation of the ITO electrode increases. Correspondingly, the work function increases.

FIG. 7 shows the relationship between the heat treatment temperature and the work function. By adjusting the heat treatment conditions, oxygen vacancies existing in the ITO electrode can be compensated. Moreover, densification of the ITO electrode is also achieved. By forming an amorphous ITO electrode containing unreacted oxygen and water in the ITO film forming step (5A), this effect can be made effective.
When an appropriate range of the heat treatment temperature is obtained from the resistance value and work function shown in FIGS. 6 and 7, it is 200 to 300 ° C.

  Further, when this heat treatment is performed in an oxidizing atmosphere, the oxidation proceeds from the ITO surface toward the inside, and the oxygen concentration distribution characteristic of the present invention shown in FIG. 2 can be obtained.

  In order to enhance this effect, it is effective to perform UV irradiation or ozone treatment together with heat treatment in an oxidizing atmosphere.

  By providing in this step, it is possible to compensate for defects (lower oxides of indium and tin) caused by oxygen deficiency in the ITO electrode generated in the film forming step.

(5D) Formation of Insulating Layer 3 An insulating film made of a SiNx film or a SiNxOy film is formed using a known plasma CVD method or the like. The insulating film is processed using known photoetching or dry etching, and an opening is provided in a region where the organic film 4 is to be formed. Since the formation of the SiNx film and the SiNxOy film is performed in a reducing atmosphere, the ITO electrode is reduced and a defect in which oxygen is lost tends to occur. When this occurs, the work function of the ITO curtain becomes low.

(5E) Cleaning of TFT circuit substrate The TFT substrate on which the insulating layer 3 is formed is cleaned using a known cleaning method (UV irradiation + brush cleaning, alkali cleaning, neutral detergent cleaning, etc.) to clean the surface.

(5F) Surface treatment of ITO electrode pattern 2 Surface treatment is performed using plasma treatment using a gas containing oxygen, UV / O3 treatment, ozone treatment, etc. to clean the ITO surface and increase the work function. In this case, the oxidation is advanced from the ITO surface toward the inside by adjusting the processing conditions. Thus, the oxygen concentration distribution characteristic of the present invention as shown in FIG. 2 is obtained. The prior art does not take this into account.

  FIG. 8 shows the relationship between processing conditions and work function when oxygen plasma processing is used. In the case of the present embodiment, the processing is 5.6 eV or higher, which is a higher value than the conventional value. This is probably because the oxidation degree of the ITO electrode is high. This principle is the same as in the case of the step (5C).

  By this step, defects due to oxygen deficiency generated in the steps up to (5E) are repaired, and an oxygen concentration distribution characteristic of the present invention as shown in FIG. 2 is obtained.

  In addition, when the oxygen concentration distribution in the ITO electrode shown in FIG. 2 which is characteristic of the present invention is obtained in the step (5C), the main purpose of this step is to clean the ITO surface.

(5G) Formation of organic EL layer 4 Using a well-known vacuum evaporation method (mask evaporation), an organic film as a hole injection layer 41, a hole transport layer 42, a light emitting layer 43, and an electron transport layer 44 is sequentially formed, The organic EL layer 4 is used.

(5H) Formation of Upper Electrode 5 Using a well-known vacuum vapor deposition method (mask vapor deposition), an LiF film and an Al film are sequentially formed to form the upper electrode 5.

  Thus, the OLED element shown in FIG. 1 to which the present invention is applied is formed. After this, an OLED panel is manufactured through a sealing process or the like, which is omitted.

  In this example, the ITO electrode of the present invention is obtained by a combination of the ITO film forming conditions in the step (5A), the heat treatment conditions in the step (5C), and the surface treatment conditions in the step (5F). However, as shown in FIG. 11, the ITO film-forming process is divided into a process (11A1) and a process (11A2), and an ITO electrode 21 is formed as a low-resistance part in the process (11A1), and the process (11A2). An ITO electrode 22 having a high oxygen content may be formed. However, in order to obtain the same effect as in this embodiment, it is preferable to use an amorphous film and to include unreacted oxygen and moisture as in the step (5A). This is because defects caused by oxygen deficiency can be compensated by heat treatment, so that a dense film can be formed and an ITO electrode having a flat surface can be formed.

  FIG. 9 shows the depth direction distribution of oxygen in an ITO electrode of a typical ITO electrode used in a conventional bottom emission type OLED. A shows the interface with the base substrate side, and B shows the interface with the organic film layer 41 (OLED layer 4). The basic structure of the organic EL element is the same as in FIG.

  FIG. 9A shows the oxygen concentration distribution of the untreated ITO electrode. The ITO electrode is an oxygen-deficient film having oxygen vacancies in order to reduce the resistance, but further, the ITO surface is more likely to be oxygen-deficient due to damage in a process such as electrode pattern formation. Therefore, a region having a high oxygen concentration and a region having a low oxygen concentration are likely to be mixed on the surface of the conventional ITO electrode. When such an ITO electrode is used as an electrode on the hole injection side of the OLED element, the work function is as low as 4.5 to 4.8 eV, so that the hole injection barrier is high and desired OLED characteristics cannot be obtained.

In FIG. 9B, oxygen plasma treatment, UV / O ₃ treatment, or the like is performed in order to compensate for the drawback of the above (A). This surface treatment increases the oxygen concentration on the surface of the ITO electrode, and the work function shows a value of 5.2 eV or more. By forming an OLED layer (hole injection layer 41) thereon, an OLED element with improved characteristics can be obtained.

  FIG. 4B shows a typical photoelectron spectrum of the ITO electrode shown in FIG. 9B. In the photoelectron spectrum, there are often two regions that can be linearly approximated, and the ITO electrode is often composed of a portion having a high work function and a portion having a low work function. The distribution of the high work function portion and the low work function portion exists in the film pressure direction, but may also occur in the plane.

In such an ITO electrode, the work function is likely to deteriorate with time after the surface treatment (oxygen plasma treatment, UV / O ₃ treatment, etc.). An example of this is shown in FIG. Such deterioration of the work function with time is considered to be remarkable when the thickness of the ITO electrode having a high work function is thin or the existence ratio on the surface is small.

  When such an ITO electrode is used for an OLED element, it is difficult to improve the characteristics of the OLED, and it is also difficult to improve the life characteristics (shortening the luminance half time and suppressing the drive voltage rise).

  Although the above-mentioned problems of the prior art are focused on cleaning the ITO surface and increasing the work function, they have occurred because the film quality of the ITO electrode and the method for maintaining the work function at a high value have not been stepped on. It is thought that there is.

  FIG. 10 is a diagram showing an oxygen concentration profile when an oxygen high concentration layer is formed with a thickness a at the interface B of the ITO electrode electrode 2 with the organic layer 4 (hole injection layer 41). This oxygen high concentration layer exhibits an oxygen concentration equal to or higher than the stoichiometric composition of the ITO electrode. Since the high oxygen concentration layer has a high work function, good hole injection characteristics can be obtained at the interface B. Considering characteristic deterioration due to mutual diffusion between the ITO electrode 2 and the organic layer 4, the thickness a may be about 1 nm. Further, since this high oxygen concentration layer has a low carrier (electron) density and exhibits a high resistance, it is not good to make the thickness too thick. When considered in combination with FIG. 2, d ≧ a must be satisfied.

  An example of the manufacturing method of the OLED element which has the ITO electrode of this Embodiment is shown in FIG. The process of forming the ITO electrode is the same as the process of forming the ITO electrode that constitutes the low-resistance part of the ITO electrode, and the ITO electrode having a high resistance and high work function containing oxygen equal to or higher than the stoichiometric composition (oxygen) What is necessary is just to divide into the process which forms a high concentration layer. One method for forming the oxygen high concentration layer is to increase the ratio of oxygen and moisture in the film formation atmosphere.

  According to the present embodiment, it is possible to reliably form an ITO electrode (oxygen high concentration layer) containing oxygen equal to or higher than the stoichiometric composition and having a high resistance and a high work function. For this reason, it is not necessary to adjust the oxygen profile of the ITO electrode by the heat treatment in the step (5C) shown in FIG. 5 or the surface treatment of (5F). (5C) is a reduction in resistance of the ITO electrode, and (5F) The main purpose is to clean the surface of the ITO electrode. Even if there is a reducing atmosphere in the manufacturing process and oxygen deficiency occurs, the oxygen concentration on the surface of the ITO electrode is high, so that repair by oxidation in the process (5F) is easy.

  FIG. 11 is a process flow diagram showing an example of a method for manufacturing an OLED element using the ITO electrode having the oxygen concentration profile shown in FIG. The difference from the process shown in FIG. 5 is that the ITO electrode film forming process (5A) is divided into two processes (11A1) and (11A2). In the step (11A1), the film quality can be lowered by the heat treatment in the step (11C), and in the step (11A2), an ITO electrode corresponding to the oxygen high concentration layer is formed. That is, in step (11A1), the film is formed at the optimum oxygen (+ water) partial pressure, but in step (11A2), the film is formed by further adding oxygen or moisture to the optimum oxygen (+ water) partial pressure.

  In the case of this example, it is not necessary to adjust the oxygen profile of the ITO electrode by the heat treatment in the step (11C) or the (11F) surface treatment. Step (11C) focuses on reducing the resistance of the ITO electrode (ITO electrode formed in step (11A1)), and step (11F) focuses on cleaning the surface of the ITO electrode (ITO electrode formed in step (11A2)). Just do it.

It is sectional drawing of bottom emission type OLED which shows 1st Embodiment. It is a figure which shows oxygen concentration distribution in the ITO electrode 2 which shows the characteristics of this invention. It is the figure which described the graph which shows one of the effects of this invention. It is the figure which described the photoelectron spectrum which shows one of the effects of this invention. It is a figure which shows the manufacturing process flowchart which shows one of the manufacturing methods of the OLED element by this invention. It is the figure which described the graph which shows the resistance change of the ITO electrode 2 (ITO electrode) by the process (5C) shown in FIG. It is the figure which described the graph which shows the work function of the ITO electrode 2 (ITO electrode) by the process (5C) shown in FIG. It is the figure which described the graph which shows the work function of the ITO electrode 2 (ITO electrode) by the process (5F) shown in FIG. It is the figure which showed the depth direction distribution of the oxygen in the ITO electrode of the typical ITO electrode used with the conventional bottom emission type | mold OLED. It is the figure which showed the oxygen concentration profile at the time of producing an oxygen high concentration layer with thickness a in the interface B with the organic layer 4 (hole injection layer 41) of the ITO electrode electrode 2. FIG. FIG. 11 is a process flow diagram showing an example of a method for manufacturing an OLED element using the ITO electrode having the oxygen concentration profile shown in FIG. .

Explanation of symbols

DESCRIPTION OF SYMBOLS 1,3 ... Insulating layer, 2 ... ITO electrode, 4 ... Organic electroluminescent layer, 41 ... Hole injection layer, 42 ... Hole transport layer, 43 ... Light emitting layer, 44 ... Electron transport layer, 5 ... upper electrode, 100 ... TFT circuit substrate, 110 ... glass substrate, 120 ... TFT circuit, A ... interface between insulating layer 1 and ITO electrode 2, B ..Interface between the ITO electrode 2 and the organic EL layer 4 (hole injection layer 41).

Claims (7)

In an organic EL display device in which organic EL elements formed by sequentially laminating an organic film and a metal film on an ITO electrode are arranged in a matrix,
In the vicinity of the boundary of the ITO electrode with the organic layer, the distribution of the oxygen content in the ITO electrode in the depth direction is a distribution increasing from the inside of the ITO electrode toward the organic film. Organic EL display device. In claim 1,
An organic EL display device characterized in that the oxygen content of the ITO electrode at the interface between the ITO electrode and the organic film is equal to or higher than the stoichiometric composition of the ITO. In claim 1 or 2,
The organic EL display device, wherein the oxygen content is an oxygen content in a range of 1 nm to 10 nm from an interface between the ITO electrode and the organic film. In an organic EL display device in which organic EL elements formed by sequentially laminating an organic film and a metal film on an ITO electrode are arranged in a matrix,
An organic EL display device comprising a layer having an oxygen concentration equal to or higher than the stoichiometric composition of ITO at an interface between the ITO and the organic layer. In claim 4,
The organic EL display device, wherein the layer has a thickness of 1 nm or more.   In claims 1 to 5, In claim 6,
The organic EL display device, wherein the organic EL element is formed on an active matrix substrate.

Images