JP2005026240A - Manufacturing method of organic electroluminescence element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of an organic electroluminescence element, having an effective lower surface side anode configuration to efficiently take light from the upper surface side cathode. <P>SOLUTION: This organic electroluminescence element is manufactured by an anode forming process of forming an anode A containing metal belonging to the fifth group or the sixth group of the periodic table on a substrate 1, an organic layer forming process of forming an organic layer 10 containing a light emission layer 10 on an anode A, and a cathode forming process of forming a cathode K on the organic layer 10. Preferably, in the anode forming process, an anode A is formed tapered. The anode forming process includes a process of forming an insulating film 15 on the anode A after patterning the anode A in a predetermined shape, and further providing the insulating film 15 with an opening to expose the metal, and in the organic layer forming process, the organic layer 10 is formed to come into contact with the metal in the opening. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing an organic electroluminescence device that can extract light emission on the cathode side of the device.

  An electroluminescence element using electroluminescence (hereinafter abbreviated as EL element) has high visibility due to self-emission and is a complete solid element, and thus has characteristics such as excellent impact resistance. The use as a light emitting element in various display devices has attracted attention.

  The EL element includes an inorganic EL element using an inorganic compound as a light emitting material and an organic EL element using an organic compound. Among these, since organic EL elements can be easily miniaturized with a significantly reduced driving voltage, practical research has been actively conducted as next-generation display elements. The structure of the organic EL element is basically a laminate of anode / light emitting layer / cathode, and a structure in which a transparent anode is formed on a substrate using a glass plate or the like is usually employed. In this case, the emitted light is extracted to the substrate side.

  In recent years, attempts have been made to extract light from the cathode side by making the cathode transparent for the following reasons. First, if the anode is made transparent together with the cathode, a transparent light emitting element as a whole can be obtained. An arbitrary color can be adopted as the background color of the transparent light emitting element, and it becomes possible to make a colorful display other than during light emission, thereby improving the decoration. When black is used as the background color, the contrast during light emission is improved. Next, when a color filter or a color conversion layer is used, these can be placed on the light emitting element. For this reason, an element can be manufactured without considering these layers. As an advantage, for example, the substrate temperature can be increased when the anode is formed, thereby reducing the resistance value of the anode.

Since the above advantages can be obtained by making the cathode transparent, an attempt has been made to produce an organic EL element using a transparent cathode. For example, in the organic EL element disclosed in the following Patent Document 1, an organic layer including an organic light emitting layer is interposed between an anode and a cathode, and the cathode includes an electron injection metal layer, an amorphous transparent conductive layer, and the like. The electron injection metal layer is in contact with the organic layer. In order to clarify the background of the present invention, these configurations will be briefly described below.
Japanese Patent Laid-Open No. 10-162959

First, the amorphous transparent conductive layer constituting the cathode in the organic EL element will be described. The amorphous transparent conductive layer may be amorphous and transparent, but has a specific resistance value of 5 × 10 ^{− in} order to eliminate voltage drop and non-uniformity of light emission resulting therefrom. It is preferably ⁴ Ω · cm or less. As a material, an In—Zn—O-based oxide film is preferable. Here, the In—Zn—O-based oxide film is a transparent conductive film made of an amorphous oxide containing indium (In) and zinc (Zn) as main cation elements.

  Next, the electron injection metal layer will be described. The electron injection metal layer is a metal layer that can inject electrons well into the organic layer including the light emitting layer. In order to obtain a transparent light emitting element, the light transmittance is preferably 50% or more. For this, it is desirable that the film thickness is an ultrathin film of about 0.5 to 20 nm. The electron injection metal layer is made of a metal having a work function of 3.8 eV or less (electron injection metal) such as Mg, Ca, Ba, Sr, Li, Yb, Eu, Y, Sc, etc. A layer having a thickness of 1 nm to 20 nm can be exemplified. In this case, a configuration that gives a light transmittance of 50% or more, particularly 60% or more is preferable.

  The organic layer interposed between the anode and the cathode includes at least a light emitting layer. The organic layer may be a layer composed only of the light emitting layer, or may have a multilayer structure in which a hole injecting and transporting layer and the like are laminated together with the light emitting layer. In the organic EL device, the organic layer has (1) a function capable of injecting holes from an anode or a hole transport layer when an electric field is applied, and (2) injection. It has a transport function that moves electric charges (electrons and holes) by the force of an electric field. . The hole injecting and transporting layer is a layer made of a hole transporting compound and has a function of transmitting holes injected from the anode to the light emitting layer. By interposing, in the light emitting layer, many holes are injected with a lower electric field. In addition, electrons injected from the electron injection layer into the light emitting layer are accumulated near the interface in the light emitting layer due to an electron barrier existing at the interface between the light emitting layer and the hole injecting and transporting layer. And an EL element with excellent light emitting performance is obtained.

The anode is not particularly limited as long as it has a work function of 4.8 eV or more. A metal having a work function of 4.8 eV or more, a transparent conductive film (conductive oxide film), or a combination thereof is preferable. The anode is not necessarily transparent and may be coated with a black carbon layer or the like. Examples of suitable metals include Au, Pt, Ni, and Pd. Examples of conductive oxides include In—Zn—O, In—Sn—O, ZnO—Al, and Zn—Sn—. O can be mentioned. Examples of the stacked body include a stacked body of Au and In—Zn—O, a stacked body of Pt and In—Zn—O, and a stacked body of In—Sn—O and Pt. In addition, since the anode only needs to have a work function of 4.8 eV or higher as the interface with the organic layer, a conductive film having a work function of 4.8 eV or lower may be used on the side where the anode is not in contact with the organic layer. Good. In this case, a metal such as Al, Ta, or W, or an alloy such as an Al alloy or Ta—W alloy can be used. Also, conductive polymers such as doped polyaniline and doped polyphenylene vinylene, amorphous semiconductors such as α-Si, α-SiC, α-C, microcrystals such as μC-Si, μC-SiC, etc. Can also be used. Further, black semiconductor oxides such as Cr ₂ O ₃ , Pr ₂ O ₅ , NiO, Mn ₂ O ₅ , MnO _{2 and the} like can be used.

  As described above, Patent Document 1 discloses a technique for extracting light from the cathode side by forming the cathode with an extremely thin electron injection metal layer and an amorphous transparent conductive layer. However, no improvements have been made to the anode. That is, there is no description of an anode on the lower surface side that is effective for efficiently extracting light from the cathode on the upper surface side. It is simply stated that a metal or a transparent conductive film having a conductivity of 4.8 eV or more, or a combination thereof can be used for the anode. Preferred metals include Au, Pt, Ni, and Pd. However, these metals do not have good adhesion to the organic layer, and are likely to generate dark spots (non-light emitting points) and uneven light emission. Furthermore, the fine processing technology of these metals has not been established, and high-definition patterning is difficult.

SUMMARY OF THE INVENTION In view of the above-described problems of the prior art, an object of the present invention is to provide a method for manufacturing an organic electroluminescence device having an effective lower surface side anode structure in order to efficiently extract light from an upper surface side cathode. And In order to achieve this purpose, the following measures were taken. That is, an organic electroluminescence device manufacturing method according to the present invention includes an anode forming step of forming an anode containing a metal belonging to Group 5 or 6 of the periodic table on a substrate, and an organic layer including a light emitting layer on the anode. An organic layer forming step of forming a layer; and a cathode forming step of forming a cathode on the organic layer.
Preferably, the anode forming step uses a metal selected from chromium, molybdenum, tungsten, tantalum and niobium. The anode forming step uses a metal having a work function of less than 4.8 eV. In the anode forming step, an anode having a reflectance of 40% or more is formed. In the anode forming step, the metal is formed on the substrate by DC sputtering using a predetermined sputtering gas. In the anode forming step, the anode is formed into a tapered shape. In the anode forming step, the anode is patterned into a predetermined shape by dry etching using a predetermined etching gas. For example, in the anode forming step, the anode is patterned into a predetermined shape by reactive ion etching. Alternatively, in the anode forming step, the anode may be patterned into a predetermined shape by wet etching using a predetermined etching solution. The anode forming step includes a process of patterning the anode into a predetermined shape, forming an insulating film on the anode, and further providing an opening in the insulating film to expose the metal. The organic layer forming step Forms an organic layer in contact with the metal at the opening.

  The method of manufacturing an organic electroluminescence device according to the present invention includes a step of forming a gate electrode on a substrate, a step of forming a gate insulating film on the gate electrode, and a semiconductor layer on the gate insulating film. Forming an insulating film on the semiconductor layer, forming an anode containing a metal belonging to Group 5 or 6 of the periodic table on the insulating film, patterning the anode, After the patterning, a step of forming another insulating film on the anode, a step of providing an opening in the other insulating film to expose the metal, and an organic light emitting layer so as to be in contact with the metal through the opening And a step of forming a cathode on the organic light emitting layer.

According to the present invention, the anode of the organic electroluminescence element is made of a metal belonging to Group 5 or 6 of the periodic table. These metals include refractory metals such as chromium, molybdenum, tungsten, tantalum and niobium. These metals have a work function of less than 4.8 eV, for example, 4.5 eV for chromium and 4.6 eV for tungsten. Further, the reflectance is 40% or more. Conventionally, metals having a work function as high as 4.8 eV or higher (Au, Pt, Ni, Pd, etc.) have been used as the anode because of the necessity of supplying holes. In the present invention, a metal belonging to Group 5 or Group 6 (Cr, Mo, W, Ta, Nb, etc.) having a low work function is used instead. It was confirmed that holes could be sufficiently supplied even for metals belonging to Group 5 or Group 6. On the contrary, chromium (Cr) has fewer defects and excellent workability than gold (Au) or the like, and is generally excellent as an anode material for organic electroluminescence elements.
In particular, if the anode is etched under predetermined conditions, a taper-like process can be performed and a short-circuit between the cathode and the anode can be reduced. Further, after patterning the anode into a predetermined shape, an insulating film is formed on the anode, and an opening is formed in the insulating film to expose the metal, and the organic layer and the cathode are in contact with the metal at the opening. By forming, a short circuit between the anode and the cathode can be prevented.
As described above, according to the present invention, light generated in the light emitting layer can be efficiently extracted from the upper electrode side which is a cathode. By using a metal having a higher reflectance than the transparent conductive film for the anode, the light transmitted to the anode side is reflected and taken out from the upper electrode side. In the present invention, good luminous efficiency can be obtained. The hole injection efficiency is substantially the same as when a transparent conductive film (for example, ITO) is used for the anode. Furthermore, the occurrence of dark spots (non-light emitting points) seen during light emission is small. In addition, the patterning of the anode can be performed with high accuracy. A high-definition display can be easily manufactured. Furthermore, the structure and process are simple. When the anode is made of ITO as in the prior art, a reflective layer such as a metal can be put underneath, but the structure and process are more complicated than those of the present invention. In addition, since light can be efficiently extracted from the upper electrode side, an organic EL element having a high aperture ratio can be manufactured on a glass substrate on which a TFT is formed, for example. When light is extracted from the lower electrode, since the TFT does not transmit light, an aperture ratio of only a few percent can be obtained. Therefore, a high-performance active matrix display can be manufactured by using the organic EL element according to the present invention. .

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a cross-sectional view showing a basic configuration of an organic electroluminescence element according to the present invention. As shown in the figure, the organic electroluminescence element includes an anode A, a cathode K, and an organic layer 10 held between the two. The organic layer 10 includes an organic light emitting layer 103 that emits light by recombination of holes supplied from the anode A and electrons supplied from the cathode K. Furthermore, a hole injection layer 101 and a hole transport layer 102 are included. The cathode K has a laminated structure of an extremely thin electron injection metal layer 11 and a transparent conductive layer 12. As a feature, the anode A includes a metal belonging to Group 5 or Group 6 of the periodic table at least in a portion in contact with the organic layer 10. Preferably, the anode metal is selected from chromium, molybdenum, tungsten, tantalum and niobium. The anode metal has a work function of less than 4.8 eV. For example, chromium is 4.5 eV and tungsten is 4.6 eV. The anode A made of these metals has a reflectance of 40% or more. That is, the anode A is light reflective, the cathode K is light transmissive, and light emission is emitted mainly from the cathode K side. In order from the top, the cathode K, the organic layer 10 and the anode A are laminated on the substrate 1. The anode A may be a single layer pure metal, a laminate or an alloy. Basically, the portion in contact with the organic layer 10 may contain a metal belonging to Group 5 or 6 of the periodic table. The anode A is a metal, an alloy, or a laminate thereof.

For example, when a chromium film having a film thickness of 200 nm was formed on the glass substrate 1 as the anode A and the reflectance was measured, it was 67% at a wavelength of 460 nm. Further, as the cathode K, an ultrathin electron injection metal layer 11 made of an alloy of Mg: Ag was formed with a thickness of 10 nm, and further, a transparent conductive layer 12 was formed with a thickness of 200 nm. When the transmittance of this laminated cathode K was measured at a wavelength of 460 nm, it was 53%. When a voltage of 8 V was applied between the anode and the cathode of the organic EL device formed as shown in the figure using these anode A and cathode K, a current of 20 mA / cm ² was observed, and 900 cd / cm from the cathode K side was observed. An emission luminance of m ² was observed. A considerable amount of light emitted toward the anode A is reflected and travels backward, and is emitted from the cathode K side. Good carrier injection characteristics and light emission characteristics could be confirmed. Also, no dark spots were seen on the light emitting surface.

As a comparative example, an organic EL element shown in FIG. 2 was prepared. The structure is basically the same as that shown in FIG. 1, and corresponding portions are denoted by corresponding reference numerals. The difference was that an organic EL element was fabricated using anode A as the transparent conductive ITO. When a voltage of 8 V was applied between the anode and the cathode of the organic EL device produced in this way, a current of 23 mA / cm ² was observed, but the emission luminance from the cathode K side was 250 cd / m ^{2, which} is the organic of FIG. It was smaller than the EL element. It shows that the light emitted in the direction of the anode A was emitted to the glass substrate 1 side with almost no reflection. As is clear from the above comparison results, the organic EL device manufactured according to the present invention can efficiently extract light emitted from the organic light emitting layer 103 from the top surface, and thus can obtain good top light emission. It is.

Hereinafter, a method for manufacturing an organic EL device according to the present invention will be described in detail with reference to FIGS. In this example, chromium was used as the anode made of metal. The work function of chromium is 4.5 eV. As shown in FIG. 3, chromium (Cr) is formed on the glass substrate 1 by DC sputtering with a film thickness of 200 nm. Argon (Ar) was used as the sputtering gas, the pressure was 0.2 Pa, and the DC output was 300 W. Patterning into a predetermined shape is performed using a normal lithography technique. Processing is performed using ETCH-1 (manufactured by Sanyo Chemical Industries, Ltd.) as an etching solution. An anode A having a predetermined shape is obtained. Chromium can be processed with high accuracy and reproducibility by the etching solution. Furthermore, when processing accuracy is required, processing by dry etching is also possible. As an etching gas, a mixed gas of chlorine (C1 ₂ ) and oxygen (O ₂ ) can be used. In particular, if reactive ion etching (RlE) is used, high-precision processing can be performed and the shape of the etched surface can be controlled. If etching is performed under predetermined conditions, a taper-like process can be performed, and a short-circuit between the cathode and the anode can be reduced.

Next, as shown in FIG. 4, an insulating layer 15 is formed on the substrate 1 on which chromium is processed into a predetermined pattern. The material used for the insulating layer 15 is not particularly limited, but silicon dioxide (SiO ₂ ) is used in this embodiment. Si0 ₂ is formed with a film thickness of 200nm by sputtering. There is no particular limitation on the film forming method. Using conventional lithographic techniques, as an opening on the chromium processing the Si0 _2. Si0 The _second etching can be used a mixture of hydrofluoric acid and ammonium fluoride. Also. Processing by dry etching is also possible. The opening becomes a light emitting portion of the organic EL element. The insulating layer 15 is not indispensable for the present invention, but it is desirable to install it in order to prevent a short-circuit between the anode and the cathode.

Subsequently, as shown in FIG. 5, the glass substrate 1 on which chromium and SiO ₂ are formed is put in a vacuum vapor deposition apparatus, and the organic layer 10 and the metal layer 11 of the cathode K are formed by vapor deposition. Here, the organic layer 10 includes 4,4 ′, 4 ″ -tris (3-methylphenylphenylamino) triphenylamine (MTDATA) as the hole injection layer 101 and bis (N-naphthyl) − as the hole transport layer 102. N-phenylbenzidine (α-NPD) and 8-quinolinol aluminum complex (Alq) were used as the light emitting layer 103. Magnesium and silver alloy (Mg: Ag) was used for the metal layer 11 of the cathode K. Organic Each material belonging to the layer 10 is filled with 0.2 g in a resistance heating boat and attached to a predetermined electrode of a vacuum vapor deposition apparatus.The metal layer 11 has 0.1 g of magnesium and 0.4 g of silver in the boat. filled, attached to predetermined electrodes of a vacuum vapor deposition apparatus. the vacuum chamber was evacuated to 1.0x10 -4 ^Pa, a voltage is applied to each boat, and successively heated steam In the vapor deposition, the organic layer 10 and the metal layer 11 made of Mg: Ag were vapor-deposited only on a predetermined portion by using a metal mask, where chromium is exposed on the substrate 1. Since it is difficult to deposit with high precision only on the exposed portion of chromium, the deposition mask covers the entire exposed portion of chromium (so as to cover the edge of the insulating layer 15). First, MTDATA was deposited as 30 nm as the hole injection layer 101, α-NPD was deposited as 20 nm as the hole transport layer 102, and Alq was deposited as 50 nm as the light emitting layer 103. Further, co-evaporation of magnesium and silver was performed. Then, Mg: Ag is deposited as the metal layer 11 of the cathode K on the organic layer 10. Magnesium and silver have a deposition rate ratio of 9: 1. It was 0nm.

Finally, as shown in FIG. 6, it moves to another vacuum chamber and forms the transparent conductive layer 12 through the same mask. DC sputtering is used for film formation. In this embodiment, an In—Zn—O-based transparent conductive film showing good conductivity at room temperature is used as the transparent conductive layer 12. The film formation conditions were a mixed gas of argon and oxygen (volume ratio Ar: O ₂ = 1000: 5) as a sputtering gas, a pressure of 0.3 Pa, and a DC output of 40 W. The film was formed with a thickness of 200 nm.

As a material of the anode A. Besides chromium, tungsten may be used. In this case, tungsten (W) is formed on the glass substrate by DC sputtering with a film thickness of 200 nm. Argon (Ar) was used as the sputtering gas, the pressure was 0.2 Pa, and the DC output was 300 W. Subsequently, patterning was performed by dry etching. As an etching gas, CF ₄ or SF ₆ can be used. In particular, if reactive ion etching (RlE) is used, high-precision processing can be performed and the shape of the etched surface can be controlled. If etching is performed under predetermined conditions, a taper-like process can be performed, and a short-circuit between the cathode and the anode can be reduced. The subsequent steps are the same as those for chromium.

  Next, the appearance characteristics of the organic EL element will be described with reference to FIGS. FIG. 7 is an image of the light emitting surface of the example using chromium (Cr) as the anode A. The light emitting surface is 2 mm square, and a slight dark spot (non-light emitting point) is observed. FIG. 8 is an image of the light emitting surface when tungsten (W) is used as the anode A. Similarly, a slight dark spot (non-light emitting point) is recognized. FIG. 9 is an image of a light emitting surface of a reference example using ITO as the anode A, and a considerable dark spot (non-light emitting point) is observed. FIG. 10 shows an image of a light emitting surface of a reference example using gold (Au) as the anode A, and a large amount of dark spots (non-light emitting points) are recognized. This is because the adhesion between the gold and the organic layer is poor.

  Finally, a display device using the organic EL element according to the present invention for pixels will be described. In general, in an active matrix display device, an image is displayed by arranging a large number of pixels in a matrix and controlling the light intensity for each pixel in accordance with given luminance information. When liquid crystal is used as the electro-optic material, the transmittance of the pixel changes according to the voltage written to each pixel. Even in an active matrix display device using an organic electroluminescence material as an electro-optical material, the basic operation is the same as that in the case of using liquid crystal. However, unlike a liquid crystal display, an organic EL display is a self-luminous type having a light emitting element in each pixel, and has advantages such as higher image visibility, no backlight, and faster response speed than a liquid crystal display. The luminance of each light emitting element is controlled by the amount of current. That is, it differs greatly from a liquid crystal display or the like in that the light emitting element is a current drive type or a current control type.

  Similar to the liquid crystal display, the organic EL display can be driven by a simple matrix system or an active matrix system. Although the former has a simple structure, it is difficult to realize a large-sized and high-definition display. Therefore, active matrix systems have been actively developed. In the active matrix method, a current flowing through an organic EL element provided in each pixel is controlled by an active element provided in the pixel (generally, a thin film transistor which is a kind of insulated gate field effect transistor, hereinafter referred to as a TFT). To do. FIG. 11 shows an equivalent circuit for one pixel of the active matrix organic EL display. The pixel PXL includes an organic EL element OLED, a thin film transistor TFT1 as a first active element, a thin film transistor TFT2 as a second active element, and a storage capacitor Cs. Since organic EL elements often have rectifying properties, they are sometimes called OLEDs (organic light-emitting diodes), and diode symbols are used in the drawings. In the illustrated example, the source S of the TFT 2 is set to a reference potential (ground potential), the cathode K of the OLED is connected to Vdd (power supply potential), and the anode A is connected to the drain D of the TFT 2. On the other hand, the gate G of the TFT 1 is connected to the scanning line X, the source S is connected to the data line Y, and the drain D is connected to the storage capacitor Cs and the gate G of the TFT 2.

  In order to operate PXL, first, when the scanning line X is selected and the data potential Vdata representing luminance information is applied to the data line Y, the TFT 1 is turned on, the holding capacitor Cs is charged or discharged, and the gate potential of the TFT 2 Corresponds to the data potential Vdata. When the scanning line X is in a non-selected state, the TFT 1 is turned off and the TFT 2 is electrically disconnected from the data line Y, but the gate potential of the TFT 2 is stably held by the holding capacitor Cs. The current flowing to the organic EL element OLED via the TFT 2 has a value corresponding to the gate / source voltage Vgs of the TFT 2, and the OLED continues to emit light with a luminance corresponding to the amount of current supplied from the TFT 2.

  As described above, in the circuit configuration of the pixel PXL shown in FIG. 11, once Vdata is written, the OLED continues to emit light at a constant luminance for one frame until it is rewritten next time. When a large number of such pixels PXL are arranged in a matrix as shown in FIG. 12, an active matrix display device can be configured. As shown in FIG. 12, in this display device, scanning lines X1 to XN for selecting a pixel PXL and data lines Y for supplying luminance information (data potential Vdata) for driving the pixel PXL are arranged in a matrix. It is arranged. The scanning lines X 1 to XN are connected to the scanning line driving circuit 21, while the data line Y is connected to the data line driving circuit 22. A desired image can be displayed by repeating the writing of Vdata from the data line Y by the data line driving circuit 22 while the scanning line driving circuit 21 sequentially selects the scanning lines X1 to XN. In the simple matrix display device, the light emitting element included in each pixel PXL emits light only at the selected moment. In the active matrix display device shown in FIG. Since the organic EL element continues to emit light, it is particularly advantageous in a large-sized high-definition display in that the peak luminance (peak current) of the organic EL element can be lowered as compared with the simple matrix type.

  FIG. 13 schematically illustrates a cross-sectional structure of the pixel PXL illustrated in FIG. However, for ease of illustration, only OLED and TFT 2 are shown. In the OLED, the anode A, the organic layer 10 and the cathode K are sequentially stacked. The anode A is separated for each pixel, and is made of, for example, chromium according to the present invention, and is basically light reflective. The cathode K is commonly connected between the pixels, and has, for example, a laminated structure of the metal layer 11 and the transparent conductive layer 12 and is basically light transmissive. When a forward voltage (about 10 V) is applied between the anode A / cathode K of an OLED having such a configuration, carriers such as electrons and holes are injected, and light emission is observed. The operation of the OLED is considered to be light emission by excitons formed by holes injected from the anode A and electrons injected from the cathode K.

  On the other hand, the TFT 2 is stacked on the gate electrode 2 formed on the substrate 1 made of glass or the like, the gate insulating film 3 stacked on the upper surface thereof, and the gate electrode 2 via the gate insulating film 3. It consists of a semiconductor thin film 4. The semiconductor thin film 4 is made of, for example, a polycrystalline silicon thin film. The TFT 2 includes a source S, a channel Ch, and a drain D, which are paths for current supplied to the OLED. The channel Ch is located just above the gate electrode 2. The bottom gate TFT 2 is covered with an interlayer insulating film 5 on which a source electrode 6 and a drain electrode 7 are formed. On top of these, the aforementioned OLED is deposited via another interlayer insulating film 9.

It is sectional drawing which shows the basic composition of the organic EL element concerning this invention. It is sectional drawing which shows the structure of the organic EL element concerning a reference example. It is process drawing which shows the manufacturing method of the organic EL element concerning this invention. Similarly, it is process drawing which shows the manufacturing method of the organic EL element concerning this invention. Similarly, it is process drawing which shows the manufacturing method of the organic EL element concerning this invention. Similarly, it is process drawing which shows the manufacturing method of the organic EL element concerning this invention. It is an enlarged plan view which shows the light emission surface of an organic EL element. Similarly, it is an enlarged plan view showing a light emitting surface of an organic EL element. Similarly, it is an enlarged plan view showing a light emitting surface of an organic EL element. Similarly, it is an enlarged plan view showing a light emitting surface of an organic EL element. FIG. 3 is an equivalent circuit diagram showing one pixel of the display device according to the present invention. It is a block diagram which shows the whole structure of the display apparatus which concerns on this invention. It is sectional drawing which shows the structure of the display apparatus which concerns on this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Glass substrate, 10 ... Organic layer, 11 ... Metal layer, 12 ... Transparent conductive layer, 15 ... Insulating layer, 103 ... Light emitting layer, A ... Anode, K ···cathode

Claims (11)

An anode forming step of forming an anode containing a metal belonging to Group 5 or 6 of the Periodic Table on the substrate;
An organic layer forming step of forming an organic layer including a light emitting layer on the anode;
And a cathode forming step of forming a cathode on the organic layer.   2. The method of manufacturing an organic electroluminescent element according to claim 1, wherein the anode forming step uses a metal selected from chromium, molybdenum, tungsten, tantalum and niobium.   2. The method of manufacturing an organic electroluminescent element according to claim 1, wherein the anode forming step uses a metal having a work function of less than 4.8 eV.   2. The method of manufacturing an organic electroluminescent element according to claim 1, wherein the anode forming step forms an anode having a reflectance of 40% or more.   2. The method of manufacturing an organic electroluminescence element according to claim 1, wherein in the anode forming step, the metal is formed on the substrate by DC sputtering using a predetermined sputtering gas.   2. The method of manufacturing an organic electroluminescent element according to claim 1, wherein in the anode forming step, the anode is formed in a tapered shape.   2. The method of manufacturing an organic electroluminescence element according to claim 1, wherein in the anode forming step, the anode is patterned into a predetermined shape by dry etching using a predetermined etching gas.   2. The method of manufacturing an organic electroluminescence element according to claim 1, wherein in the anode forming step, the anode is patterned into a predetermined shape by reactive ion etching.   2. The method of manufacturing an organic electroluminescence element according to claim 1, wherein the anode forming step includes patterning the anode into a predetermined shape by wet etching using a predetermined etching solution. 3. The anode forming step includes a process of patterning the anode into a predetermined shape, forming an insulating film on the anode, and further providing an opening in the insulating film to expose the metal,
2. The method of manufacturing an organic electroluminescence element according to claim 1, wherein the organic layer forming step forms an organic layer so as to be in contact with the metal at the opening. Forming a gate electrode on the substrate;
Forming a gate insulating film on the gate electrode;
Forming a semiconductor layer on the gate insulating film;
Forming an insulating film on the semiconductor layer;
Forming an anode containing a metal belonging to Group 5 or 6 of the periodic table on the insulating film;
Patterning the anode;
After the patterning, forming another insulating film on the anode;
Providing an opening in the other insulating film to expose the metal;
A method for producing an organic electroluminescent device, comprising: forming an organic light emitting layer so as to be in contact with the metal at the opening; and forming a cathode on the organic light emitting layer.

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