JPH11204264A - Electroluminescence element and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily manufacture a layered product presenting luminescent colors of green (G) and blue (B) in a simple process at a low cost. SOLUTION: Transparent electrodes 5 common to two kinds of electroluminescence element sections 21G, 21B are formed on a glass substrate 6 common to the electroluminescence element sections 21G, 21B, and hole transportation layers 4a, 4b made of a common hole transportation layer forming material layer are formed on the regions including the electroluminescence element sections 21G, 21B on the transparent electrodes 5. Electron transportation layers 2 made of a common electron transportation layer forming material layer are formed on the regions including the electroluminescence element sections 21G, 21B on the regions including the hole transportation layers 4a, 4b, and cathode electrodes 1 of the electroluminescence element sections 21G, 21B are formed to face the transparent electrodes 5 on the electron transportation layers 2. The blue electroluminescence element sections 21B have hole block layers 33.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electroluminescent device and a method of manufacturing the same, for example, a self-luminous flat display, and in particular, a display such as an organic electroluminescent color display using an organic thin film as an electroluminescent layer. The present invention relates to an electroluminescent element suitable for an element or a light emitting device and a method for manufacturing the same.

[0002]

2. Description of the Related Art In recent years, the importance of interfaces between humans and machines, such as multimedia-oriented products, has been increasing. In order for humans to operate the machine more comfortably and efficiently, it is necessary to extract information from the operated machine in a simple, instantaneous, and sufficient amount without errors. Research has been conducted on display elements.

Further, with the miniaturization of machines, the demand for miniaturization and thinning of display elements is increasing every day.

[0004] For example, there has been a remarkable progress in miniaturization of laptop information processing devices which are integrated with display elements, such as notebook personal computers and notebook word processors. There are also great innovations regarding

[0005] Today, the liquid crystal display is used as an interface for various products.
It is widely used in our everyday products, including calculators.

[0006] These liquid crystal displays have been studied as small-sized to large-capacity display devices as interfaces between humans and machines as the center of display elements, taking advantage of the characteristics that liquid crystals are driven at low voltage and low power consumption. .

However, since this liquid crystal display is not self-luminous, it requires a backlight, and this backlight requires more power than driving the liquid crystal. Is shorter and there are restrictions on use.

Another problem is that the liquid crystal display is not suitable for a large display device such as a large display because the viewing angle is narrow.

Further, since the liquid crystal display is a display method based on the alignment state of liquid crystal molecules, it is considered that a significant problem that the contrast varies depending on the angle even within the viewing angle.

In view of the driving method, the active matrix method, which is one of the driving methods, shows a response speed sufficient to handle moving images.
Since a driving circuit is used, it is difficult to increase the screen size due to pixel defects.

In a liquid crystal display, a simple matrix system, which is another driving system, is low in cost and relatively easy to enlarge the screen size, but does not have a sufficient response speed for handling moving images. There is a problem.

On the other hand, as a self-luminous display element, a plasma display element, an inorganic electroluminescent element, an organic electroluminescent element and the like have been studied.

The plasma display device uses plasma emission in a low-pressure gas for display, and is suitable for increasing the size and the capacity, but has problems in terms of thickness and cost.
Further, it requires a high voltage AC bias for driving, and is not suitable for portable devices.

As the inorganic electroluminescent device, a green light-emitting display or the like has been commercialized, but like the plasma display device, it is driven by an AC bias, and requires several hundred volts for driving, and is not practical.

However, due to the development of technology, three primary colors of R (red), G (green), and B (blue) necessary for color display display have been successfully emitted. It is difficult to control the emission wavelength and the like by using the method described above, and it is considered that full-color display is difficult.

On the other hand, the electroluminescence phenomenon caused by an organic compound is as follows.
It has been studied for a long time since the light emission phenomenon caused by carrier injection into an anthracene single crystal that emits strong fluorescence was discovered in the early 1960s. It was performed as a basic study of carrier injection into materials.

However, in 1987 Eastman Kodak
Since Tang et al. Announced a stacked organic thin-film electroluminescent device with an amorphous light-emitting layer capable of low-voltage driving and high-luminance light emission, the R, G, and B primary colors of light emission, stability, and brightness have been observed in various directions. Research and development on ascending, laminating structure, manufacturing method, etc. are being actively conducted.

Further, as a feature of the organic material, various new materials have been invented by molecular design and the like, and the color of the organic electroluminescent display element has excellent features such as low-voltage DC drive, thinness, and self-luminous property. Research on application to displays is also being actively pursued.

An organic electroluminescent device (hereinafter sometimes referred to as an organic EL device) has a thickness of 1 μm or less, and converts electric energy into light energy by injecting a current to emit light in a planar manner. It has ideal characteristics as a self-luminous display device.

FIG. 31 shows an example of a conventional organic EL device 10. In the organic EL device 10, an ITO (Indium tin oxide) transparent electrode 5, a hole transport layer 4, a light emitting layer 3, an electron transport layer 2, and a cathode (eg, an aluminum electrode) 1 are formed on a transparent substrate (eg, a glass substrate) 6. For example, they are sequentially formed by a vacuum deposition method.

Then, by selectively applying a DC voltage 7 between the transparent electrode 5 as an anode and the cathode 1, holes as carriers injected from the transparent electrode 5 pass through the hole transport layer 4. Electrons injected from the cathode 1 move through the electron transport layer 2 to cause recombination of electrons and holes, from which light emission 8 having a predetermined wavelength is generated, which can be observed from the transparent substrate 6 side.

The light-emitting layer 3 may use a light-emitting substance such as anthracene, naphthalene, phenanthrene, pyrene, chrysene, perylene, butadiene, coumarin, acridine, and stilbene. This can be contained in the electron transport layer 2.

FIG. 32 shows another conventional example.
An organic EL in which the light emitting layer 3 is omitted, the electron transporting layer 2 contains the light emitting substance as described above, and light emission 18 of a predetermined wavelength is generated from the interface between the electron transporting layer 2 and the hole transporting layer 4.
4 shows an element 20.

FIG. 33 shows a specific example of the above-mentioned organic EL device. That is, a laminated body of each organic layer (the hole transport layer 4, the light emitting layer 3, or the electron transport layer 2) is disposed between the cathode 1 and the anode 5, and these electrodes are crossed in a matrix to form a stripe. A luminance signal circuit 34 and a control circuit 35 with a built-in shift register apply a signal voltage in a time series to emit light at a number of intersection positions (pixels).

Therefore, with such a configuration, it can be used not only as a display but also as an image reproducing apparatus. The above-mentioned stripe patterns can be arranged for each of R, G, and B colors, and can be configured for full-color or multi-color.

In a display device composed of a plurality of pixels using such an organic EL element, the light emitting organic thin film layers 2, 3, and 4 are generally sandwiched between the transparent electrode 5 and the metal electrode 1, and Light is emitted to the electrode 5 side.

[0027]

However, the organic EL device as described above still has an unsolved problem.

In order to apply an organic EL element to a color display, stable light emission of each color is an indispensable condition. However, when a completely different material system is used for each color system in the device process, The process becomes extremely complicated and takes time.

An object of the present invention is to provide an electroluminescent device having an element structure which can be manufactured simply and at low cost and can emit light stably, and a method for manufacturing the same.

[0030]

Means for Solving the Problems The present inventors diligently study the above-mentioned circumstances, and use simple and inexpensive materials by using as common a material as possible in two kinds of laminates having light emitting regions of each color. The inventors have found that a device can be manufactured, and have reached the present invention.

That is, according to the present invention, there are provided two kinds of organic substance laminates in which the light emitting region is independently present in the hole transport layer and the electron transport layer, and these laminates are formed of a common material layer. The present invention relates to an electroluminescent device having a hole transport layer and the electron transport layer made of a common material layer, and exhibiting two emission colors.

According to the electroluminescent device of the present invention, the hole transport layer and the electron transport layer are formed of a common material between the respective laminates in which the light emitting regions are independently provided in the hole transport layer and the electron transport layer. Therefore, a laminate that emits light of each color can be manufactured easily and at low cost by a simple process. Moreover, by forming each of the common layers with a large aperture mask over the entire effective pixel region, the film formability or the step coverage is improved, and the leakage current between the cathode and the anode can be reduced.

According to the present invention, there is provided a method of manufacturing the electroluminescent device of the present invention with good reproducibility, wherein a step of forming a first electrode common to two kinds of the above-mentioned laminated bodies on a common base during the manufacturing. Forming a common hole transport layer forming material on a region including the two types of stacked bodies on the first electrode to form respective hole transport layers; and a region including the respective hole transport layers. Forming a common electron transport layer forming material on a region including the two types of laminates to form each electron transport layer; and forming the two types of laminates on each electron transport layer. Forming a second electrode facing the first electrode.

[0034]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the electroluminescent device and the method of manufacturing the same according to the present invention, the light-emitting region is made of an organic compound, and the laminate has two kinds of the above-mentioned laminates made of an organic substance containing the light-emitting region. In one kind of body, it is desirable that blue light emission can be obtained by recombination of electrons and holes in the hole transporting organic material.

According to such an electroluminescent device, light emission by electron-hole recombination can be obtained in the above-mentioned hole transporting organic material (that is, the hole transport layer is an electron-hole recombination region). The structure also serves as the light emitting layer)
As a result, stable and high-luminance light emission, particularly blue light emission, is possible even at low voltage driving.

Accordingly, the electroluminescent device (especially low-voltage driving, self-luminous,
In the case of a thin amorphous organic electroluminescent element, a long-life electroluminescent element having a hole transport layer also serving as a light emitting layer and providing long-term stable light emission can be provided.

That is, even in an organic electroluminescent device in which the hole transport layer is a light emitting layer, stable light emission with high luminance and high efficiency can be obtained.
Peak luminance of 550 in DC conversion even in pulse drive at 10,000 cd / m ² or more and 1/100 duty ratio in C drive
It is possible to obtain 00 cd / m ² or more.

Further, other than the blue light emitting element, green light emission,
Further, red light emission and yellow light emission by doping, and chromaticity by doping can be adjusted. As a result, it is possible to produce an organic electroluminescent blue light-emitting device capable of obtaining blue light emission with excellent chromaticity at high luminance, and to shorten the time and the potential for material development. A guideline for designing electron transport materials can be provided.

In the electroluminescent device and the method of manufacturing the same according to the present invention, it is preferable that the light emitting region is mainly an organic hole transport layer, and that the hole transport layer has a hole blocking layer for causing the recombination.

It is preferable that the hole blocking layer is provided between the hole transport layer and the electron transport layer.

The highest occupied molecular orbital level of the hole block layer is the highest occupied molecule of each organic layer (particularly, the hole transport layer and the electron transport layer) stacked on both sides of the hole block layer. It is desirable to be at or below the highest occupied molecular orbital level which is lower in energy among the orbital levels.

The minimum unoccupied molecular orbital level of the hole block layer is the minimum unoccupied molecular orbital level of each of the organic layers (particularly, the hole transport layer and the electron transport layer) laminated on both sides of the hole block layer. It is desirable that the occupied molecular orbital level be higher than the lowest unoccupied molecular orbital level which is lower in energy and lower than the lowest unoccupied molecular orbital level which is higher in energy.

The hole block layer is desirably made of a non-luminescent material having a low fluorescence yield, and may have a multilayer structure of a plurality of layers.

Further, the material of the hole blocking layer is not limited in terms of material, but is to prevent the generation of exciplex (excimer: dimer) at the interface with the hole transporting light emitting layer (ie, decrease in luminous efficiency). In particular, it is preferable that the material is a non-luminescent material having a low fluorescence yield.

It is preferable that the light emitting region is made of a hole transporting material for short wavelength light emission. Further, as a material that can be used for the hole blocking layer, a phenanthroline derivative shown in FIG. 6 is preferable, and specific examples include, for example, structural formula 1 shown in FIG. 7, structural formula 2 shown in FIG. FIG.
Structural formula 3 shown in FIG. 10, structural formula 4 shown in FIG. 10, structural formula 5 shown in FIG. 11, structural formula 6 shown in FIG. 12, structural formula 7 shown in FIG. 13, structural formula 8 shown in FIG. Each material of the structural formula 9 and the structural formula 10 shown in FIG.

Further, the light emitting region is made of an organic compound, and two kinds of the above-mentioned laminates made of an organic substance containing the light emitting region are provided. It is desirable that green light emission can be obtained by recombination of holes.

As described above, by stacking an organic layer for obtaining blue light emission due to electron-hole recombination in the light emitting region as a hole block layer, stable, high luminance and low voltage drive hole transporting light emission. A green light emission by electron-hole recombination in the electron transport layer can be obtained in the layered region of the organic material without the hole blocking layer, while obtaining an organic electroluminescent device having a layer.
It is possible to provide an excellent organic electroluminescent device that can handle B.

The above element is formed on an optically transparent substrate by
It is preferable that a transparent electrode, an organic layer (particularly, an organic hole transport layer, a hole block layer, an organic electron transport layer) and a metal electrode are sequentially laminated.

In this case, the transparent electrode,
The organic layer and the metal electrode are preferably configured as an organic electroluminescent device forming a matrix pattern.

As a result, the above-mentioned element is constituted as a suitable organic electroluminescent element, and is also suitable as an element for a color display.

Hereinafter, preferred embodiments of the present invention will be described.

<First Embodiment> FIG. 5 is a schematic sectional view showing a main part of an organic EL element 21 according to a first embodiment of the present invention.

The organic EL device 21 according to the present embodiment is
Organic light-emitting element portions 21B (blue), 21 each composed of a laminate of amorphous organic thin films for emitting two types of colors.
G (green) is provided on a common glass substrate 6.

In the blue light emitting element portion 21 B shown in FIG. 5A, a glass or
(Indium Tin Oxide), a transparent electrode 5 made of Zn-doped indium oxide or the like (hereinafter the same) is formed by a method such as sputtering or vacuum evaporation, and a hole transport layer 4a for blue light emission is sequentially formed thereon. Hole transporting light emitting layer 4b, hole blocking layer 33, electron transporting layer (or electron transporting light emitting layer) 2, cathode electrode 1 as column electrode
Are laminated by a vacuum evaporation method.

In the green light emitting element portion 21G shown in FIG. 5B, the transparent electrode 5 made of ITO (Indium Tin Oxide) or the like is formed on a glass substrate 6 by a method such as sputtering or vacuum evaporation. The hole transporting layer 4a, the hole transporting light emitting layer 4b, the electron transporting layer 2 for emitting green light, and the cathode electrode 1 as a column electrode are sequentially laminated by a vacuum deposition method, and the hole blocking layer is not provided.

The feature of the organic EL element 21 shown in FIG. 5 is that the transparent electrode 5 is used as a row electrode or a line electrode common to the two types of light emitting elements on the glass substrate 6 common to the light emitting elements 21B and 21G. On the transparent electrode, each hole transport layer 4a, 4b made of a common hole transport layer forming material is formed on a region including each light emitting element portion, and on a region including each of these hole transport layers, Each electron transport layer 2 made of a common electron transport forming material is formed on a region including each light emitting element section, and further, on each of these electron transport layers, a cathode 1 of each light emitting element section is formed by a transparent electrode. 5 (or in a matrix pattern). However, each light emitting element section has a specific layer configuration, and the blue light emitting element section 21B has the hole block layer 33 in, for example, a stripe pattern, but the green light emitting element section 21G has the hole block layer 33 provided. Not.

Therefore, in each light emitting element portion, a light emitting region exists independently in the hole transport layer 4 (4a, 4b) and the electron transport layer 2, and the hole transport layer 4 is provided between each light emitting element portion.
Since (4a, 4b) and the electron transport layer 2 are each formed of a common material, it is possible to easily and inexpensively produce a laminate that emits light of each color by a simple process. Moreover, by forming each of the common layers with a large aperture mask over the entire effective pixel region, the film formability or the step coverage is improved, and the leakage current between the cathode and the anode can be reduced. Since two-color display is possible, it is suitable for character display.

The blue light emitting element portion 21B is provided with the hole transport layer 4
Is configured as a structure having the performance as a light emitting layer, and the basic structure is the same in other embodiments described later.

The feature of the element portion 21 B of the present embodiment is that the hole block layer 33 is inserted between the hole transport layer 4 and the electron transport layer 2 and laminated, and Is promoted, and light emission in the hole transport layer 4 can be obtained.

FIG. 17 shows the above-described embodiment (FIG. 5).
(A)) is a diagram schematically showing a layered structure by a band model.

In FIG. 17, a cathode 1 made of Al and Al-Li (aluminum-lithium) and ITO
The bold lines (L ₁ , L ₂ ) shown in the layer of the transparent electrode 5 are the approximate work functions of the respective metals, and the upper bold lines l ₁ , l ₂ , l ₃ , l ₄ and numbers indicate the level of each of the lowest unoccupied molecular orbital (LUMO), thick line _{l 5, l 6, l 7} , l 8 and numerical lower indicates the level of the respective highest occupied molecular orbital (HOMO) ing. However, the energy level value in FIG. 17 is an example, and changes variously depending on the material.

In this organic EL device, as shown in FIG. 17, the holes h injected from the transparent electrode 5 as the anode move through the hole transport layer 4, while being injected from the metal electrode 1 of the cathode. The electrons e move through the electron transporting layer 2, and the electron-holes are transferred to the hole transporting light emitting layer 4.
Recombine to generate light.

Since the electron e injected from the metal electrode 1 as a cathode has a property of moving to a lower energy level, the metal electrode 1, the electron transport layer 2, the hole blocking layer 33, the hole transporting light emitting layer 4b , Hole transport layer 4a
The lowest unoccupied molecular orbital (LUMO) level l of each layer in the order of
Hole transport light emitting layer 4b via the ₁ to l _4, it can be reached 4a.

On the other hand, an ITO transparent electrode 5 as an anode
The hole h injected from the hole has the property of moving to a higher energy level, and therefore the highest occupied molecular orbital (HOMO) level l of each layer in the order of the hole transport layer 4a, the hole transportable light emitting layer 4b, and the hole block layer 33. It can move to the electron transport layer 2 via _{5 to} l ₇ .

[0065] However, as shown in FIG. 17, it is energetically lower for the highest occupied molecular orbital (HOMO) level l ₈ of the electron-transport layer 2 than the highest occupied molecular orbital (HOMO) level l ₇ of the hole blocking layer 33 Therefore, the injected holes h are less likely to move from the hole block layer 33 to the electron transport layer 2 and fill the hole block layer 33.

As a result, the holes h filled in the hole blocking layer 33 promote the recombination of electrons and holes in the hole transport layer 4, and the luminescent materials of the hole transportable light emitting layers 4a and 4b constituting the hole transport layer 4 Will emit light.

As described above, by providing the hole block layer 33, the transport of holes h is effectively controlled in the hole block layer 33 so that the electron-hole recombination is efficiently generated in the hole transport layer 4. . Then, the hole transporting light emitting layers 4a, 4b emitting light by this.
Of these, mainly the light emitted by the hole transporting light emitting layer 4b adjacent to the hole blocking layer 33 is
Light emission of a specific wavelength (blue) is emitted as shown in FIG.

Originally, electron injection from the cathode electrode 1 and hole injection from the anode electrode 5 cause the electron transport layer 2 and the hole transport layer 4 to have electron-
Hole recombination occurs. Therefore, when the hole blocking layer 33 does not exist as described above, recombination of electrons and holes occurs at the interface between the electron transport layer 2 and the hole transport layer 4, and only long-wavelength light emission can be obtained. However, by providing the hole blocking layer 33 as in this embodiment, it becomes possible to promote blue light emission by using the hole transport layer 4 containing a light emitting substance as a light emitting region.

As described above, the hole block layer 33 is for controlling the transport of the holes h. For this purpose, the highest occupied molecular orbital (HOM) of the hole block layer 33 is used.
O) is at or below the highest occupied molecular orbital (HOMO) level of the energetically lower level of the highest occupied molecular orbital (HOMO) level of the hole transporting light emitting layer 4b and the electron transporting layer 2; The lowest unoccupied molecular orbital (LUMO) of the hole transporting light-emitting layer 4b and the electron transporting layer 2 has the lowest unoccupied molecular orbital (LUMO) of 33.
MO) or higher, and not higher than the lowest energy occupied lowest unoccupied molecular orbital (LUMO) level.
It is not limited to the above configuration.

The above-described hole block layer 33 can be formed of various materials, and the thickness thereof can be changed as long as its function can be maintained. Its thickness is 1mm ~
The thickness is preferably set to 1000 ° (0.1 nm to 100 nm). If the thickness is too small, the hole blocking ability is incomplete and the recombination region is likely to straddle the hole transport layer and the electron transport layer. Light may not be emitted due to an increase in resistance.

In the green light emitting element portion 21G, since the hole blocking layer 33 is not provided, holes enter the electron transport layer 2 and electron-hole recombination occurs in the electron transport layer 2. The electron transport layer 2 emits light and emits light of a specific wavelength (green) as shown in FIG.

The above-mentioned organic EL element 21 is manufactured by using a vacuum evaporation apparatus 11 as shown in FIG. Inside the device is a pair of support means 1 fixed below the arm 12.
A stage mechanism (not shown) that allows the transparent glass substrate 6 to face downward and sets the mask 22 is provided between the two fixing means 13 and 13.
The shutter 14 supported by the support shaft 14a is arranged below the glass substrate 6 and the mask 22, and a predetermined number of various evaporation sources 28 are arranged below the shutter 14. Each evaporation source is heated by a power supply 29 by a resistance heating method. For this heating, an EB (electron beam) heating method or the like is used as necessary.

In the above apparatus, the mask 22 is for a pixel, and the shutter 14 is for a vapor deposition material. And
The shutter 14 rotates around the support shaft 14a, and shuts off the vapor flow of the material according to the sublimation temperature of the vapor deposition material.

Actually, two types of masks 22 are used as shown in FIG. 19, and various types of films are formed in a predetermined pattern by appropriately changing them. After the above-described hole transport layer 4 is commonly formed on each element portion through the large opening 23a using the mask 22a, the hole block layer 33 is formed using the mask 22b or 22c to form one of the slit-like openings 23b or one of the openings 23a. /
A predetermined pattern is formed in the blue light emitting element portion 21B through the opening 23c of two sizes, and then the electron transport layer 2 is formed in common in each element portion through the large opening 23a using a mask 22a. The cathode electrode 1 is formed in a predetermined pattern on each element portion using a not shown).

Thus, as shown in FIG. 19, each light emitting element portion 21 B, 2
1G is formed. This may be in the form of a stripe, and the stripe may be divided into respective light emitting areas by an insulating layer (not shown here). In this case, when the light emitting element portions are formed in the same pattern on the transparent electrode 5 so as to be stacked, the carrier transportability between the cathode and the anode is improved,
The voltage drop between both electrodes can be reduced. Although the organic layer 33 is formed on the transparent electrode 5 in the line direction, it may be formed in the column direction orthogonal to the transparent electrode 5.

FIG. 1, FIG. 2, FIG. 3, and FIG. 4 are diagrams showing two specific examples of the organic EL element 21 or 21 ′ manufactured by the above-described vacuum deposition apparatus. That is, in the example of FIGS. 1 and 2, on a glass substrate 6, the ITO transparent electrode 5 after deposition by vacuum evaporation apparatus described above, a blue light emitting portion 21B in the region surrounded by the insulating layer 24 such as SiO ₂ green A light emitting portion 21G is provided continuously, and a transparent electrode 5 is provided inside the insulating layer.
Is exposed to the pixel pattern. Next, the organic layers 4a, 4b, 33, and 2 and the metal electrode 1 (for example, a laminated body of the LiF layer 1a and the Al layer 1b) are commonly formed on each light emitting unit using an evaporation mask. This example is suitable for displaying characters such as characters as shown in FIG. 2B by applying the light emission pattern schematically shown in FIG. In the examples of FIGS. 3 and 4, after the ITO transparent electrode 5 serving as a line electrode is formed by vapor deposition, SiO ₂ 24 is vapor deposited in a predetermined pattern along the column direction, and the transparent electrode 5 is interposed between the SiO _2. Each of the organic layers 4a, 4b, 3
After the formation of the electrodes 3 and 2, the electrode 1 as a column electrode is formed in a stripe pattern in the column direction to form a matrix. The above-mentioned vapor deposition mask 22a, 22b or 22c
Are used to form the organic layers 4 and 2 and 33.

According to these organic EL elements 21 and 21 ′, in each of the light emitting element portions, the light emitting regions are independently present in the hole transport layer 4 (4 a, 4 b) and the electron transport layer 2, respectively. Since the hole transport layer 4 (4a, 4b) and the electron transport layer 2 are formed of a common material layer between the parts, a laminate (for example, a matrix) that emits light of each color can be easily and easily formed by a simple process. It can be manufactured at low cost. In addition, since the organic layers 4a, 4b, and 2 are formed over a large area, the film forming properties including the insulating layer 24 are improved, the leakage current between the cathode and the anode is small, and stable and reliable performance is achieved. Can be obtained. This is shown in FIG.
If the upper surface of the insulating layer 24 is curved, as shown by a broken line in FIG.

In the above-described vacuum vapor deposition apparatus 11, in addition to the above-described apparatus having pixels as shown in FIGS. 1 to 4, the shape and size can be changed, and a large number of small pixels can be individually or large. Can be formed alone.

The transparent electrode, the organic hole transporting layer, the organic hole blocking layer, the organic electron transporting layer, and the metal electrode of the electroluminescent device may have a laminated structure composed of a plurality of layers.

Further, each organic layer in the above-mentioned electroluminescent device may be formed by other film formation methods involving sublimation or vaporization, or methods such as spin coating and casting, in addition to vacuum evaporation.

The hole transporting light emitting layer of the above-mentioned electroluminescent device may be subjected to co-evaporation of trace molecules for controlling the emission spectrum of the device. For example, organic materials such as perylene derivatives and coumarin derivatives may be used. May be an organic thin film containing a trace amount of

Materials usable as the hole transport material include benzidine or a derivative thereof, styrylamine or a derivative thereof, triphenylmethane or a derivative thereof, porphyrin or a derivative thereof, triazole or a derivative thereof, imidazole or a derivative thereof. , Oxadiazole or its derivative, polyarylalkane or its derivative, phenylenediamine or its derivative, arylamine or its derivative, oxazole or its derivative, anthracene or its derivative, fluorenone or its derivative, hydrazone or its derivative, stilbene or its derivative Derivatives, and heterocyclic conjugated monomers, oligomers, polymers, and the like such as polysilane compounds, vinylcarbazole compounds, thiophene compounds, and aniline compounds are given.

Specifically, α-naphthylphenyldiamine, porphyrin, metal tetraphenylporphyrin,
Metal naphthalocyanine, 4,4 ′, 4 ″ -trimethyltriphenylamine, 4,4 ′, 4 ″ -tris (3-methylphenylphenylamino) triphenylamine, N,
N, N ', N'-tetrakis (p-tolyl) p-phenylenediamine, N, N, N', N'-tetraphenyl-
4,4′-diaminobiphenyl, N-phenylcarbazole, 4-di-p-tolylaminostilbene, poly (paraphenylenevinylene), poly (thiophenvinylene), poly (2,2′-thienylpyrrole) and the like. However, the present invention is not limited to these.

Examples of materials usable as the electron transporting material include quinoline or a derivative thereof, perylene or a derivative thereof, bisstyryl or a derivative thereof, and pyrazine or a derivative thereof.

Specific examples thereof include 8-hydroxyquinoline aluminum, anthracene, naphthalene, phenanthrene, pyrene, chrysene, perylene, butadiene, coumarin, acridine, stilbene, and derivatives thereof.

Further, an anode electrode of the electroluminescent device,
There is no limitation on the material used such as the cathode electrode.

For the cathode electrode material, in order to inject electrons efficiently, it is preferable to use a metal having a small work function from the vacuum level of the electrode material.
In addition to the lithium alloy, for example, a low work function metal such as aluminum, indium, magnesium, silver, calcium, barium, and lithium may be used alone or as an alloy with another metal with increased stability.

In order to extract organic electroluminescence from the anode electrode side, ITO which is a transparent electrode was used for the anode electrode in the later-described embodiment. Alternatively, an electrode having a large work function, for example, gold, tin dioxide-antimony mixture, or zinc oxide-aluminum mixture may be used.

Further, by selecting a light emitting material,
A color or multicolor organic electroluminescent element that emits two colors of G and B can be manufactured. Others
The present invention can be applied not only to displays but also to organic electroluminescent devices that can be used as light sources,
It can be applied to other optical applications.

The above-mentioned organic electroluminescent element may be sealed with germanium oxide or the like to enhance the stability to eliminate the influence of oxygen or the like in the atmosphere. The element may be driven.

<Second Embodiment> FIG. 24 is a schematic sectional view showing a main part of a blue light emitting element portion 21B according to a second embodiment of the present invention.

In the organic EL device according to the present embodiment, as compared with the device of FIG. 5, a hole transporting light emitting layer 4b is formed on the ITO transparent electrode 5, and the hole transporting light emitting layer is formed as a single layer. Is different. The other green light emitting element portion 21G is the same as the element in FIG.

<Third Embodiment> FIG. 25 is a schematic sectional view showing a main part of a blue light emitting element section 21B according to a third embodiment of the present invention.

In the organic EL device according to the present embodiment, a hole transporting layer (also serving as a hole transporting light emitting layer) 4a is formed on the ITO transparent electrode 5 as compared with the device shown in FIG. The hole transporting light emitting layer is formed as a single layer as in the embodiment. Other than that, it is the same as the above-described second embodiment.

[0095]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to Examples.

Example 1 A specific structure of the organic EL device according to the present example will be described based on a manufacturing method thereof.

First, a 30 mm × 30 mm glass substrate 6
ITO on which an ITO electrode 5 (thickness: about 100 nm) is provided
2 mm × 2 m by vacuum deposition of SiO ₂ 24 on the substrate
An ITO substrate for manufacturing an organic electroluminescent device was prepared by masking a region other than the light emitting region of m.

Next, as the hole transport layer 4a, m-MT
DATA (4,4 ', 4 "-tris (3-methylphenylph
enylamino) triphenylamine (of the structural formula in FIG. 20) was deposited under vacuum at a deposition rate of 0.2 to 0.4 nm / sec by vacuum deposition to a thickness of 30 nm.

Next, α-NPD (α-naphtyl phen) which functions as a hole transporting layer or a hole transporting light emitting layer 4b.
yl diamine: having a structural formula shown in FIG. 21) was vacuum-evaporated to a thickness of 50 nm under vacuum to a deposition rate of 0.2 to 0.4 n.
Deposition was performed at m / sec.

Next, the opening 23c was replaced with a mask 22c having an area of 1 mm × 2 mm so as to half cover a light emitting area of 2 mm × 2 mm, and bathocuproine (2,9-dimethyl) was used.
-4,7-diphenyl-1,10-phenanthroline: FIG.
Of the structural formula 2) as the hole blocking layer 33
Vacuum deposited at a deposition rate of 0.2 to 0.4 nm / sec to a thickness of nm.

Next, a mask is formed by setting the area of the opening 23a to 2 m.
m × 2 mm 22a and Alq ₃ (8-hydroxy qu.) functioning as an electron transporting layer or an electron transporting light emitting layer 2
inoline aluminum (of the structural formula in FIG. 23) is 40 nm
Vacuum deposited to a thickness of.

Next, LiF was vacuum-deposited to a thickness of about 0.5 nm as the cathode electrode 1, and then Al was deposited to a thickness of 200 nm.
The organic electric field blue / green light emitting device 21 shown in FIG.

The characteristics of the organic electric field blue / green light emitting device thus manufactured were measured, and the results are shown.

FIG. 26 is a graph showing the spectral characteristics of the organic EL element 21 according to the first embodiment. That is, in the emission region having bathocuproine functioning as a hole blocking layer, the maximum emission wavelength was 460 nm, and the coordinates on the CIE chromaticity coordinates were (0.16, 0.14), indicating good blue light emission. From the shape of the emission spectrum, it was clear that the emission was from α-NPD. In addition, the light-emitting site without bathocuproine is composed of an electron-transporting light-emitting material, Al.
emission from q ₃ are obtained, the maximum emission wavelength 520 nm, C
Good green light emission of IE (0.33, 0.55) was obtained.

As shown in FIG. 27, the luminance at a current density of 350 mA / cm ² was 6000 cd / m ^{2 in} the blue light emitting portion and 4000 in the green light emitting portion.
It was 0 cd / m ² .

Further, the organic EL device was manufactured by setting the duty ratio to 1
/ 100 pulse drive, current density 5500m
When converted to DC drive at A / cm ² , peak luminance is 5
5000 cd / m ² , and a high-performance and high-brightness blue light-emitting element portion capable of sufficiently withstanding practical use could be manufactured.

The blue / green light-emitting element thus manufactured has a blue light-emitting area, which is light emitted from α-NPD having a light-emitting area of 1 mm × 2 mm, and a light-emitting area of 1 mm × 2 mm in the same light-emitting area having a light-emitting area of 2 mm × 2 mm. and an element having a respective green light emitting region is a light emission from Alq _3.

Example 2 A specific structure of the organic EL device according to the present example will be described based on a manufacturing method thereof.

First, a 30 mm × 30 mm glass substrate 6
ITO on which an ITO electrode 5 (thickness: about 100 nm) is provided
2 mm × 2 m by vacuum deposition of SiO ₂ 24 on the substrate
An ITO substrate for manufacturing an organic electroluminescent device was prepared by masking a region other than the light emitting region of m.

An α-N layer functioning as a hole transporting layer or a hole transporting light emitting layer 4b is formed on the ITO substrate.
PD (α-naphtyl phenyl diamine: having the structural formula shown in FIG. 21) was deposited to a thickness of 50 nm (deposition rate: 0.2 to 0.4 nm / sec) by vacuum deposition under vacuum.

Next, a mask 22c having an opening 23c having an area of 1 mm × 2 mm and covering a half of a light emitting area of 2 mm × 2 mm was replaced with bathocuproine (2,9-dimethyl).
-4,7-diphenyl-1,10-phenanthroline: FIG.
(Shown by Structural Formula 2) as a hole blocking layer 33 having a thickness of 20 nm (a deposition rate of 0.2 to 0.4 nm / sec).
Vacuum deposited in c).

Next, a mask is formed by setting the area of the opening 23a to 2 m.
m × 2 mm 22a, and Alq ₃ (8-hydroxy qu.) functioning as an electron transporting layer or an electron transporting light emitting layer.
inoline aluminum (of the structural formula in FIG. 23) is 40 nm
Vacuum deposited to a thickness of.

Next, as a cathode electrode 1, LiF was vacuum-deposited to a thickness of about 0.5 nm, and then Al was deposited to a thickness of 200 nm.
Vacuum deposited to a thickness of 2 mm, and the organic electric field blue / green light emitting element 2
1 was produced.

The characteristics of the organic electric field blue / green light emitting device thus manufactured were measured, and the results are shown.

That is, as in the organic EL device 21 according to the first embodiment, the maximum emission wavelength is 460 nm in the emission region having bathocuproine functioning as a hole blocking layer, and the CI
The coordinates on the E chromaticity coordinates were (0.155, 0.11), and exhibited good blue light emission. From the shape of the emission spectrum, it was clear that the emission was from α-NPD. In the light-emitting portion without bathocuproin, light was emitted from Alq ₃ which is an electron-transporting light-emitting material, and excellent green light emission having a maximum emission wavelength of 520 nm and a CIE (0.33, 0.55) was obtained.

Regarding the brightness, the current density was 350 m
The luminance at A / cm ² was 1500 cd / m ² .

The blue / green light-emitting element thus manufactured has a blue light-emitting area, which is light emitted from α-NPD having a light-emitting area of 1 mm × 2 mm, and a light-emitting area of 1 mm × 2 mm in the same light-emitting area having a light-emitting area of 2 mm × 2 mm. and an element having a respective green light emitting region is a light emission from Alq _3.

Embodiment 3 A specific structure of the organic EL device according to the present embodiment will be described based on a manufacturing method thereof.

First, 8 × 9 (8 lines × 9 columns) (G
× 2, B × 1) To prepare a simple matrix, 30
Eight lines of ITO are formed on a glass substrate 6 mm × 30 mm as line-side electrodes 5 with a width of 2.0 mm, an interval of 0.54 mm, a film thickness of about 100 nm, and an insulating layer formed on the column side by vacuum evaporation of SiO _2. 24 were formed at a width of 1.0 mm and an interval of 1.54 mm. One EL formed
The light emitting area of the cell was 1.54 × 2.0 mm ² , and the aperture ratio was 52.6%.

The mask is 19.78 mm × 24.86 mm
8 × 9 (G)
× 2, B × 1) First, an organic layer was vapor-deposited so as to cover all light-emitting portions of the simple matrix.

M-MTDATA as the hole transport layer 4a
(4,4 ', 4 "-tris (3-methylphenylphenylamin
o) triphenylamine: having the structural formula in FIG. 20) under vacuum at a deposition rate of 0.2 to 0.4 nm / sec by a vacuum deposition method.
Α-NPD (α-naphtyl phenyl) which functions as a hole transporting layer or a hole transporting light emitting layer 4b to a thickness of 0 nm.
diamine: having a structural formula shown in FIG. 21) is deposited to a thickness of 50 nm under vacuum by a vacuum deposition method (a deposition rate of 0.2 to 0.1 mm).
4 nm / sec).

Next, the light emitting area of ITO of 2.0 mm
The area of the opening is 2.1 m on a × 30 mm stripe.
The mask was replaced with one of the masks 22b in which three striped openings 23b of mx 30 mm were opened for each color, and bathocuproine (2,9-dimethyl-4,7-diphenyl-) was used.
1,10-phenanthroline: having a structural formula of 2 in FIG.
Vacuum deposited at a deposition rate of 0.2 to 0.4 nm / sec to a thickness of m.

Next, the area of the mask opening 23a is set at 19.
Return to the mask 22a of 78 mm × 24.86 mm, and Alq functioning as an electron transporting layer or an electron transporting light emitting layer 2
₃ (8-hydroxy quinoline aluminum: having the structural formula in FIG. 23) was vacuum-deposited to a thickness of 40 nm.

Next, the mask was replaced with a mask having a stripe-shaped opening, and LiF was vacuum-deposited to a thickness of about 0.5 nm as the cathode electrode 1 for each stripe (three types of masks were used). Vacuum deposited to a thickness of
The organic electric field blue / green light emitting device 21 shown in FIG. 3 was manufactured.

The organic electroluminescent device in the simple matrix manufactured as described above has a large aperture area of m-MTDATA, α
-Since NPD was deposited, there was almost no leakage current and simple matrix driving was possible.

When the characteristics of the simple matrix were measured, the maximum emission wavelength was 460 nm for the stripe having bathocuproine functioning as a hole blocking layer, and the CI
The coordinates on the E chromaticity coordinates were (0.16, 0.14), and exhibited good blue light emission. Current density 350mA / c
The luminance at m ² was 1600 cd / m ² . From the shape of the emission spectrum, it was clear that the emission was from α-NPD. In the light-emitting portion without bathocuproin, light was emitted from Alq ₃ which is an electron-transporting light-emitting material.
55) Good green light emission was obtained.

Embodiment 4 An organic EL device according to a fourth embodiment of the present invention will be described based on a method for manufacturing the same.

In the organic EL device according to this embodiment, the hole transporting layer 4a is not provided, and the hole transporting light emitting layer 4b is formed as α.
-NPD (α-naphtyl phenyldiamine: having the structural formula of FIG. 21. This is the α-PPD of FIG. 22 (A) or FIG.
2 (B) α-TPD or (C) TPD may be used. )
Is deposited under a vacuum by a vacuum deposition method to a thickness of, for example, 50 nm (deposition rate: 0.2 to 0.4 nm / sec), and the above-described first method is performed except that the hole transporting light emitting layer is formed as a single layer. This is the same as the embodiment.

FIG. 28 is a graph showing the spectral characteristics of the organic EL device according to Example 4 shown in FIG.

In the case of this example, the maximum emission wavelength (absorption peak) was about 460 nm, and the coordinates on the CIE chromaticity coordinates were (0.155, 0.11), indicating good blue light emission. The green light emission was the same as in FIG.

Then, as shown in FIG.
The luminance at 0 mA / cm ² was 1400 cd / m ² .

From the shape of the emission spectrum, it was clear that the light was emitted from the hole transporting light emitting layer 4b composed of α-NPD in the blue light emitting portion.

Further, as shown in the threshold voltage characteristics of FIG. 30, almost no current flows until the voltage reaches about 5 V, and the current starts flowing gradually after passing 5 V and rapidly flows out after passing 6 V. That is, it indicates that low-voltage driving is possible and threshold voltage characteristics are good.

As is apparent from the above description, in the organic EL devices of Examples 1 to 4 according to the present invention, the hole blocking layer 33 is made of the hole transporting luminescent material 4a and / or 4b.
By providing between the electron transport layer 2 and the electron transport layer 2, the electron-hole recombination in the hole transport layer becomes sufficient, and the hole transport layer 2 can also serve as a light emitting layer, and highly efficient and stable light emission can be obtained.

Each of the above-described examples shows that it is possible to manufacture an organic EL device capable of obtaining blue luminescence with excellent chromaticity and high luminance even when using an existing material. It is considered that the possibility and time reduction in the above can be realized, and the design guideline of a new light emitting material system and an electron transport material can be shown.

[0136]

As described above, according to the present invention, the hole transport layer and the electron transport layer are made of a common material between the laminates in which the light emitting regions are independently provided in the hole transport layer and the electron transport layer. Since it is formed, it is possible to easily and inexpensively produce a laminate that emits each color of light by a simple process. Moreover, by forming each of the common layers with a large aperture mask over the entire effective pixel region, the film formability or the step coverage is improved, and the leakage current between the cathode and the anode can be reduced.

In particular, light emission due to electron-hole recombination can be obtained in the hole transporting organic material (in particular, the hole blocking layer is inserted between the hole transporting light emitting material and the electron transporting layer). Conventional structure)
Even with an organic electroluminescent device in which a hole transport layer is a light-emitting layer, which has been considered to be a difficult structure due to the absence of an electron transporting material having excellent non-light-emitting properties, stable light emission with high luminance and high efficiency is obtained. be able to. In particular, the emission of blue light is remarkable, and is 10000 cd / m ² or more and 1
Even with pulse driving at a duty ratio of / 100, it is possible to obtain a peak luminance of 55000 cd / m ² or more in DC conversion.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of an organic EL device according to an embodiment of the present invention.

FIG. 2 is a schematic plan view of a main part of the organic EL device.

FIG. 3 is a cross-sectional view (A) orthogonal to the anode and a cross-sectional view (B) of FIG. 3 (A) (B)-(B) line of the main part of the organic EL device according to another embodiment of the present invention. Cross section)
It is.

FIG. 4 is a schematic exploded perspective view of the organic EL element.

FIGS. 5A and 5B are schematic cross-sectional views of main parts of the organic EL element according to the first embodiment of the present invention, wherein FIG. 5A shows a blue light emitting element part and FIG. 5B shows a green light emitting element part.

FIG. 6 is a diagram showing a general formula of a phenanthroline derivative which can be used for the hole blocking layer.

FIG. 7 is a diagram showing the structural formula 1 of the phenanthroline derivative.

FIG. 8 is a diagram showing Structural Formula 2 of the phenanthroline derivative.

FIG. 9 is a diagram showing the structural formula 3 of the phenanthroline derivative.

FIG. 10 shows a structural formula 4 of the phenanthroline derivative.

FIG. 11 shows a structural formula 5 of the phenanthroline derivative.

FIG. 12 is a diagram showing the structural formula 6 of the phenanthroline derivative.

FIG. 13 is a drawing showing the structural formula 7 of the phenanthroline derivative.

FIG. 14 shows a structural formula 8 of the phenanthroline derivative.

FIG. 15 shows a structural formula 9 of the phenanthroline derivative.

FIG. 16 shows a structural formula 10 of the phenanthroline derivative.

FIG. 17 is a band model diagram schematically showing a stacked structure of the organic EL element according to the embodiment.

FIG. 18 is a schematic sectional view of a vacuum evaporation apparatus used in the embodiment.

FIG. 19 is a schematic plan view of an evaporation mask used in the embodiment and an organic EL device manufactured.

FIG. 20 shows m-MTDATA used in the embodiment.
It is a figure which shows the structural formula of (a hole transporting light emitting material).

FIG. 21 is a diagram showing a structural formula of α-NPD (hole transporting light emitting material) used in the embodiment.

FIG. 22 shows another hole-transporting light-emitting material that can be used in the embodiment, in which (A) is a structural formula of α-PPD,
(B) is a diagram showing a structural formula of α-TPD, and (C) is a diagram showing a structural formula of TPD.

FIG. 23 is a diagram showing a structural formula of Alq ₃ (electron transport material) used in the embodiment.

FIG. 24 is a schematic sectional view of a main part of an organic EL device according to a second embodiment of the present invention.

FIG. 25 is a schematic sectional view of a main part of an organic EL device according to a third embodiment of the present invention.

FIG. 26 is a graph showing the spectral characteristics of the organic EL device according to the first embodiment of the present invention.

FIG. 27 is a graph showing current-luminance characteristics of the organic EL device according to the first embodiment.

FIG. 28 is a graph showing spectral characteristics of an organic EL device according to another embodiment of the present invention.

FIG. 29 is a graph showing the electric current of an organic EL device according to another embodiment of the present invention;
5 is a graph showing luminance characteristics.

FIG. 30 is a graph showing the voltage of an organic EL device according to another embodiment of the present invention.
5 is a graph showing luminance characteristics.

FIG. 31 is a schematic sectional view showing an example of a conventional organic EL element.

FIG. 32 is a schematic sectional view showing an example of another organic EL element.

FIG. 33 is a schematic perspective view showing a specific example of the organic EL element.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Metal electrode (cathode), 2 ... Electron transport layer, 4 ... Hole transport layer, 4a, 4b ... Hole transport light emitting layer, 5 ... IT
O transparent electrode (anode), 6 ... glass substrate, 10, 2
0, 21: Organic EL element, 21G: Green light emitting element part, 2
1B: blue light emitting element portion, 22, 22a, 22b, 22c
... Evaporation mask, 24 ... Insulating layer, 33 ... Hole block layer, e ... Electron, h ... Hole

Claims (22)

[Claims] 1. A light-emitting region having two types of organic substance laminates which are independently present in a hole transport layer and an electron transport layer, respectively. An electroluminescent device, comprising: the electron transport layer formed of a common material layer; and emitting two colors of light. 2. The light-emitting region is made of an organic compound, and the laminate has two kinds of laminates made of an organic substance including the light-emitting region. The electroluminescent device according to claim 1, wherein blue light emission is obtained by recombination of holes. 3. The electroluminescent device according to claim 2, further comprising a hole blocking layer for causing the recombination in the hole transport layer. 4. The electroluminescent device according to claim 3, wherein said hole blocking layer is provided between a hole transport layer and an electron transport layer. 5. The highest occupancy of the highest occupied molecular orbital level of the hole block layer, which is lower in energy among the highest occupied molecular orbital levels of the organic layers stacked on both sides of the hole block layer The electroluminescent device according to claim 3, which is at a molecular orbital level or lower. 6. The lowest unoccupied molecular orbital level of the hole block layer is lower in energy among the lowest unoccupied molecular orbital levels of the organic layers stacked on both sides of the hole block layer. 4. The electroluminescent device according to claim 3, wherein the electroluminescent device is at or above the lowest unoccupied molecular orbital level and is at or below the lowest energy unoccupied molecular orbital level. 7. The electroluminescent device according to claim 3, wherein the light emitting region is made of a hole transporting material for short wavelength light emission, and the hole blocking layer is made of a phenanthroline derivative. 8. The light-emitting region is made of an organic compound, and the laminate has two kinds of laminates made of an organic substance including the light-emitting region. In one of these laminates, one of the laminates has an electron-transporting organic material. The electroluminescent device according to claim 1, wherein green light emission is obtained by recombination of holes. 9. The electroluminescent device according to claim 1, wherein a transparent electrode, an organic layer, and a metal electrode are sequentially laminated on an optically transparent substrate. 10. The organic electroluminescent device in which the transparent electrode, the organic layer, and the metal electrode form a matrix pattern on the same substrate.
2. The electroluminescent device according to item 1. 11. The electroluminescent device according to claim 10, wherein the electroluminescent device is configured as a device for a color display. 12. A light emitting region having two kinds of laminates of an organic substance independently present in a hole transport layer and an electron transport layer. When manufacturing an electroluminescent device characterized by exhibiting two emission colors, the electron transport layer comprising a common material layer, the two types of laminates are formed on a common substrate. Common first
Forming an electrode, forming a hole transport layer on the first electrode by forming a common hole transport layer forming material on a region including the two kinds of stacked bodies, and forming each hole. A step of forming a common electron transport layer forming material on the area including the two kinds of stacked bodies to form each electron transport layer on the area including the transport layer; Forming a second electrode of each kind of the stacked body facing the first electrode. 13. The light-emitting region is formed of an organic compound,
13. The method according to claim 12, wherein two kinds of the laminate including the organic substance including the light emitting region are formed, and one of the laminates emits blue light by recombination of electrons and holes in the hole transporting organic material. A method for manufacturing the described electroluminescent device. 14. The method according to claim 13, wherein a hole blocking layer for causing the recombination in the hole transport layer is formed. 15. The method according to claim 14, wherein the hole blocking layer is provided between the hole transport layer and the electron transport layer. 16. The highest occupation of the highest occupied molecular orbital level of the hole block layer, which is lower in energy among the highest occupied molecular orbital levels of the organic layers stacked on both sides of the hole block layer. The method of manufacturing an electroluminescent device according to claim 14, wherein the molecular orbital level is equal to or lower than the molecular orbital level. 17. The energies of the lowest unoccupied molecular orbital levels of the hole blocking layer, which are lower than the lowest unoccupied molecular orbital levels of the organic layers stacked on both sides of the hole blocking layer. 15. The method of manufacturing an electroluminescent device according to claim 14, wherein the level is set to be equal to or higher than the lowest unoccupied molecular orbital level and equal to or lower than the lowest energy unoccupied molecular orbital level. 18. The method according to claim 14, wherein the light emitting region is formed of a hole transporting material for short wavelength light emission, and the hole blocking layer is formed of a phenanthroline derivative. 19. The light emitting region is formed of an organic compound,
The method according to claim 12, wherein two kinds of the laminates made of the organic substance including the light emitting region are formed, and one of the laminates emits green light by recombination of electrons and holes in the electron transporting organic material. A method for manufacturing the described electroluminescent device. 20. A transparent electrode on an optically transparent substrate,
The method according to claim 12, wherein the organic layer and the metal electrode are sequentially laminated. 21. The method according to claim 20, wherein an organic electroluminescent device in which the transparent electrode, the organic layer, and the metal electrode form a matrix pattern on the same substrate is manufactured. 22. The method according to claim 21, wherein an element for a color display is manufactured.