JPH09232077A - Optical element and manufacture therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical element to stably emit the light by arranging and evaporating a host material and a guest material different in a light emitting wave length on a single evaporating boat in the same vacuum evaporation device, and a manufacturing method therefor. SOLUTION: In an organic EL element 21 where an ITO(indium tin oxide) transparent electrode 5, a hole transport layer 4, a light emitting layer 3 and a metallic electrode 1 are formed on a glass substrate 6, a guest material having a sublimating temperature lower than a host material of the light emitting layer 3 is arranged in the same evaporating boat, and these are sublimated according to respective sublimating temperatures, and the light emitting layer 3 is formed by doping the guest material to the host material in the object concentration distribution.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical element and a method for manufacturing the same, and, for example, an optical element suitable for an organic electroluminescent display which is a self-luminous flat display and particularly uses an organic thin film as an electroluminescent layer. Element and a manufacturing method thereof.

[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 smaller and thinner display elements is increasing daily.

[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.

Further, since the liquid crystal display has a narrow viewing angle, it is not suitable for a large display element such as a large display, and since it is a display method based on the alignment state of liquid crystal molecules, the viewing angle depends on the angle. Changing the contrast is also a big problem.

In terms of the driving method, the active matrix method, which is one of the driving methods, exhibits a response speed sufficient for handling moving images, but it is a TFT (thin film transistor).
Since a driving circuit is used, it is difficult to increase the screen size due to pixel defects. It is not preferable to use a TFT drive circuit from the viewpoint of cost reduction.

The simple matrix method, which is another driving method, is low in cost and relatively easy to increase the screen size, but has a problem that it does not have a sufficient response speed for handling moving images. is there.

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 element uses plasma light emission in a low pressure gas for display, and is suitable for large size and large capacity, but has problems in thinning 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 and the like have been commercialized, but like the plasma display device, it is driven by an AC bias and requires several hundreds of volts for driving, and it is difficult to realize full color. I think that the.

On the other hand, the electroluminescence phenomenon due to the organic compound is
Since the discovery of a luminescence phenomenon due to carrier injection into anthracene single crystal that strongly emits fluorescence in the first half of the 1960s,
Although it has been researched for a long period of time, it was performed as a basic research of carrier injection into an organic material because of its low brightness, monochromatic color and single crystal.

However, in 1987, Eastman Kodak's Tang
Since they announced an organic thin film electroluminescent device with a laminated structure having an amorphous light emitting layer capable of low voltage driving and high brightness light emission, the light emission of the three primary colors of R, G and B, stability,
Research and development such as increase in brightness, laminated structure, and manufacturing method are actively conducted.

Further, regarding the characteristic of the organic material, various novel materials have been invented due to the molecular design and the like, and the color of the organic light emitting display device has excellent characteristics such as direct current low voltage drive, thinness and self-luminance. Applied research on displays is also being actively conducted.

The organic electroluminescence device (hereinafter, also referred to as an organic EL device) has a film thickness of 1 μm or less, and converts electric energy into light energy by injecting a current to emit light in a plane. It has ideal characteristics as a self-luminous display device.

FIG. 22 shows an example of a conventional organic EL element 10. This organic EL element 10 includes an ITO (Indium tin oxide) transparent electrode 5, a transparent substrate (for example, a glass substrate) 6,
The hole transport layer 4, the light emitting layer 3, the electron transport layer 2, and the cathode (for example, an aluminum electrode) 1 are sequentially formed by, for example, a vacuum vapor deposition method.

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

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

FIG. 23 shows another conventional example. In this example, the light emitting layer 3 is omitted, and the electron transporting layer 2 is made to contain a mixture with the above zinc complex or a fluorescent substance. Light emission of a predetermined wavelength from the interface between the transport layer 2 and the hole transport layer 4
18 shows an organic EL element 20 configured so that 18 occurs.

FIG. 24 shows a specific example of the above organic EL element. That is, a laminated body of each organic layer (hole transport layer 4, light emitting layer 3 or 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 shape. A signal voltage is applied in time series by the luminance signal circuit 30 and the control circuit 31 with a built-in shift register, and light is emitted at each of a large number of intersection positions (pixels).

Therefore, with such a structure, it can be used not only as a display but also as an image reproducing apparatus. The above stripe pattern can be arranged for each color of red (R), green (G), and blue (B) to be configured for full color or multi-color.

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

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

For example, in applying an organic EL element to a color display, stable light emission of the three primary colors of R, G and B is an essential condition. However, at this stage, there are no reports on red and blue materials that have sufficient stability, chromaticity, and brightness that can be applied to displays, in addition to green light emitting materials, and they are being studied in various fields. Is the reality. In addition, the chromaticity of aluminum-quinoline complex, which is promising as a green light emitting material, is slightly deviated at present.

Therefore, it is ideal that the light emitting layer is composed of a single organic material and emits light. However, in order to improve chromaticity and brightness, a host-guest light emitting layer (host material: main light emitting material). , Guest material: it is essential to make and adjust the added luminescent material).

[0028]

SUMMARY OF THE INVENTION An object of the present invention is to combine various light emitting materials such as the above host material and guest material so that the light emission wavelength changes depending on the applied voltage, and various light emitting elements can be obtained in one device. An object of the present invention is to provide an optical element such as a light emitting element capable of obtaining an emission wavelength, and a manufacturing method capable of manufacturing the optical element relatively easily.

[0029]

That is, according to the present invention, in an optical element in which an organic layer including a light emitting region is provided on an electrode, at least a part of the light emitting region includes a first light emitting material and a second light emitting material. A light emitting material, the light emitting wavelengths of these light emitting materials are different from each other, and the first light emitting material has a higher vaporization temperature than the second light emitting material,
In addition, the present invention relates to an optical element having at least an electron transporting property among an electron transporting property and a hole transporting property.

The present invention also provides an optical element in which an organic layer including a light emitting region is provided on an electrode, and a part of the light emitting region contains a first light emitting material and a second light emitting material, Emission wavelengths of the light emitting materials are different from each other, the first light emitting material has a higher vaporization temperature than the second light emitting material, and has at least an electron transporting property of an electron transporting property and a hole transporting property. An optical element having, under or above the portion of the light emitting region, another light emitting portion mainly containing the first light emitting material or the second light emitting material. It is a thing.

The present invention also provides an optical element in which an organic layer including a light emitting region is provided on an electrode, at least a part of the light emitting region contains a first light emitting material and a second light emitting material, The emission wavelengths of these light emitting materials are different from each other, the first light emitting material has a lower vaporization temperature than that of the second light emitting material, and at least the hole transporting property and the electron transporting property are included. The present invention relates to an optical element having

The present invention also provides an optical element in which an organic layer including a light emitting region is provided on an electrode, a part of the light emitting region contains a first light emitting material and a second light emitting material, Emission wavelengths of the light emitting materials are different from each other, the first light emitting material has a lower vaporization temperature than the second light emitting material, and at least the hole transporting property and the electron transporting property of the hole transporting property. An optical element having, under or above the portion of the light emitting region, another light emitting portion mainly containing the first light emitting material or the second light emitting material. It is a thing.

Each optical element of the present invention can be formed by combining the above-mentioned first and second light emitting materials having different vaporization temperatures so that the concentration of each material in the light emitting region is distributed. The light emitting wavelength is changed according to the applied voltage, and it becomes an optical element such as a variable light emitting element in which various light emitting wavelengths can be obtained by one element.

Further, the first light emitting material and the second light emitting material having different light emitting wavelengths are vaporized, and a light emitting region having a light emitting portion containing these light emitting materials is provided in at least a part of the organic layer as an electrode. In forming the above, as the first light emitting material, a light emitting material having a higher vaporization temperature than the second light emitting material and having at least an electron transporting property and an electron transporting property is used. The present invention relates to a method for manufacturing an optical element.

By vaporizing at least one of the first light emitting material and the second light emitting material having different light emitting wavelengths from each other, the light emitting portion containing these light emitting materials is adjacent to the light emitting portion below or above the light emitting portion. When forming the first light emitting material or the other light emitting portion containing the second light emitting material as a main component on the electrode as at least a part of the organic layer, the second light emitting material is used as the first light emitting material. The present invention relates to a method for manufacturing an optical element, which uses a light emitting material having a higher vaporization temperature than that of the light emitting material and having at least an electron transporting property among an electron transporting property and a hole transporting property.

Further, the first light emitting material and the second light emitting material having different light emitting wavelengths are vaporized, and a light emitting region having a light emitting portion containing these light emitting materials in at least a part is used as at least a part of the organic layer as an electrode. In forming the above, as the first light emitting material, a light emitting material having a vaporization temperature lower than that of the second light emitting material and having at least hole transporting property among hole transporting property and electron transporting property is used. The present invention relates to a method for manufacturing an optical element.

By vaporizing at least one of the first light emitting material and the second light emitting material having different light emitting wavelengths, the light emitting portion containing these light emitting materials is adjacent to the light emitting portion below or above the light emitting portion. When forming the first light emitting material or the other light emitting portion containing the second light emitting material as a main component on the electrode as at least a part of the organic layer, the second light emitting material is used as the first light emitting material. The present invention relates to a method for manufacturing an optical element, which uses a light emitting material having a vaporization temperature lower than that of a light emitting material and having at least a hole transporting property among hole transporting properties and electron transporting properties.

By the respective manufacturing methods of the present invention, the optical element of the present invention can be manufactured relatively easily. Then, when each light emitting material is vaporized by the same vapor deposition source or the like, an optical element such as an organic electroluminescent element having good characteristics is produced by a vacuum integrated process with less burden on the production process and equipment. It will be possible.

In the present invention, the above-mentioned "part of the light emitting region" means "a region containing both the first light emitting material and the second light emitting material".

The "vaporization" is a concept including both "sublimation: a phenomenon in which a solid directly becomes a gas, and evaporation: a phenomenon in which a liquid or a solid becomes a liquid and then becomes a gas".

[0041]

BEST MODE FOR CARRYING OUT THE INVENTION The optical element according to the present invention is such that the content of the second light emitting material is controlled in the light emitting region and has a concentration gradient in the thickness direction, or
It is desirable that they are dispersed at arbitrary positions in the thickness direction.

The above optical element, depending on the applied voltage,
A change in the chromaticity of the emission spectrum is realized.

The above-mentioned device is prepared by forming on an optically transparent substrate,
It is desirable that a transparent electrode, an organic hole transport layer, an organic light emitting layer and / or an organic electron transport layer, and a metal electrode are laminated.

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

In the manufacturing method of the present invention, the second
It is desirable to control the content of the light emitting material in the light emitting region, form a concentration gradient in the thickness direction of the light emitting region, or disperse the light emitting material at any position in the thickness direction of the light emitting region.

Then, it is desirable to stack a transparent electrode, an organic hole transport layer, an organic light emitting layer and / or an organic electron transport layer and a metal electrode on an optically transparent substrate.

The above element can be formed as a suitable organic electroluminescent element, and is also suitable as an element for a color display.

[0048]

EXAMPLES Examples of the present invention will be described in detail below.

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

In this embodiment, as shown in FIG.
A transparent electrode 5 made of ITO (Indium Tin Oxide) is formed on a glass substrate 6 by a vacuum deposition method, and sequentially formed thereon.
Hole transport layer 4 made of TPD (N, N'-diphenyl-N, N'-di (3-methylphenyl) 4,4'-diaminobiphenyl) (see FIG. 6 for structural formula), amorphous (hereinafter the same. The host-guest light emitting layer 3) and the aluminum cathode electrode 1) are laminated by a vacuum vapor deposition method to fabricate an organic electroluminescent device 21.

Therefore, similar to FIG. 23 described above, the element having this organic electroluminescent layer is a single hetero type organic electroluminescent element in which the light emitting layer 3 also functions as an electron transporting layer (or hole transporting layer). Is.

According to this embodiment, the light emitting layer 3 is provided as a host.
As the guest-based light-emitting layer, Alq ₃ (tris (8-quinolinol) aluminum) (see FIG. 4 for the structural formula), which is an aluminum-quinoline complex, is used as a host material, and a combination of guest materials having a sublimation temperature lower than that of the host material is used. DCM commonly used as laser dye
(4-dicyanomethylene-6- (p-dimethylaminostyryl) -2-methyl-4H-pyran) (the structural formula is shown in FIG.
(Refer to FIG. 3), and a weight ratio of Alq ₃ / DCM = 6/1 (a composition ratio in a vapor deposition boat described later) is used for vapor deposition to fabricate a red light emitting device.

The portion A of FIG. 1 (a) is shown enlarged (b).
As shown in the figure, the light emitting layer 3 is basically composed of _three layers: a layer 3a containing Alq _{3 as a} main component, a mixed layer 3b containing Alq ₃ + DCM, and a layer 3c containing a DCM main component.

Each of these layers was prepared by the vapor deposition apparatus and vapor deposition method described later, and A having a high sublimation temperature was used as a host material so as to obtain a desired emission wavelength.
using the lq _3, low DCM sublimation temperature as a guest material
It is important to dope.

That is, when the temperature is raised during vapor deposition, first, DCM having a low sublimation temperature is mainly sublimated to form the layer 3
was deposited as c, followed by even higher Alq ₃ sublimation temperature was deposited as a mixture layer 3b of the sublimation began with Alq ₃ and DCM, the layers 3a which is finally Alq ₃ After completion DCM sublimates was mainly deposited is formed It

Strictly speaking, however, the layer 3c is a layer containing DCM as a main component at the interface with the TPD layer 4, and DC
Although the amount of DCM in Alq ₃ gradually decreases as it approaches the interface between the layer 3c containing M main component and the layer 3b of Alq ₃ + DCM, the content of DCM is high.

The layer 3a containing Alq _{3 as a} main component is made of Alq _{3.
In the} vicinity of the interface between ₃ + DCM and layer 3b, DCM is still present.
Are mixed and gradually decrease to almost 100% of Alq _{3 at} the interface with the metal electrode 1, the content of Alq ₃ is high, and a layer having an electron transporting property is formed.

As described above, the light emitting layer 3 of this embodiment is
From the layer 3b of lq ₃ + DCM, the layer 3c of the DCM main component on one side constituting the light emitting region portion adjacent thereto, and the layer 3a of the Alq ₃ main component on the other side having both the light emitting region and the electron transporting property. Has become. All of these form the respective regions of the light emitting layer.

In contrast to the above, a guest material having a higher sublimation temperature than the sublimation temperature of the host material can be doped into the host material. In this case, since the host material is first sublimated and vapor-deposited, the host material needs to be formed to have a hole transporting property.

As described above, the content of the guest material with which the host material is doped can be arbitrarily controlled by the vacuum vapor deposition device described later. Thereby, the concentration gradient of the guest material contained in the laminated thickness direction can be arbitrarily formed, or the arrangement thereof can be arranged at any position.

The structure of the light emitting layer 3 is not limited to that shown in FIG. 1B, but as shown in FIG.
A structure without c can also be used. Thereby, it is also possible to obtain light emission of a wavelength different from the above.

As a result, it becomes possible to manufacture organic EL elements having various element structures, obtain various emission wavelengths, and produce arbitrary colors from a wide wavelength range.

FIG. 2 is a cross-sectional view of a vapor deposition boat for vapor deposition of the above-mentioned host material and guest material, and FIG. 3 is an exploded perspective view thereof.

As shown in the figure, the vapor deposition boat 32 has a main body 35 having a first storage tank 35a and a second storage tank 35b partitioned by a partition plate 36, an inner lid 34 having vapor outflow holes 37, 38, and
The upper lid 33 has a steam outlet hole 39.

As shown in FIG. 2, the vapor outflow hole 37 of the inner lid 34 is located on the first storage tank 35a of the main body 35, and the vapor outflow hole 38 is also located on the second storage tank 35b. There is. Moreover, the upper lid 33 forms a cavity 33a.

Therefore, when the host material is put in the first storage tank 35a and the guest material is put in the second storage tank 35b, the vaporized material reaching the sublimation temperature is vaporized by the vapor outflow holes 37 provided in the respective upper portions. Or spilled from 38, alone or on top 33
The mixture is mixed in the cavity 33a and flows out from the vapor outflow hole 39 of the upper lid 33 to the outside.

For example, a material having a high sublimation temperature is stored in the storage tank 35a.
In addition, when a material having a low sublimation temperature is put in the storage tank 35b and vapor deposition is performed, first, the material from the storage tank 35b is vaporized preferentially, and then vaporization occurs from both, so that the obtained vapor deposition film is desired. A concentration distribution of is formed.

Then, such a container is arranged as a vapor deposition source in the vacuum vapor deposition apparatus 11 as shown in FIG. Inside this device, a pair of supporting means 13 fixed below the arm 12 is provided, and the transparent glass substrate 6 is faced downward between the both fixing means 13, 13 so that the mask 22 can be set. A stage mechanism (not shown) is provided. The shutter 14 supported by the support shaft 14a is disposed below the glass substrate and the mask 22, and a predetermined number of various vapor deposition sources 32 or 28 are disposed below the shutter 14. Each evaporation source is a power source
It is heated by the resistance heating method by 29. For this heating, an EB (electron beam) heating method or the like is used as necessary.

In the above device, the mask 22 is for pixels and the shutter 14 is for host material and guest material. Then, the shutter 14 rotates about the support shaft 14a,
It is for shutting off the vapor flow of the material according to the sublimation temperature of the host material and the guest material.

Therefore, in vapor deposition, for example, when the sublimation temperature of the host material is high and the sublimation temperature of the guest material is low, if the shutter 14 is opened first, the guest material is first sublimated by heating and the substrate 6 Evaporate on top. Although the guest material is formed to a predetermined thickness in this way, if it takes time to sublimate the host material, once
By closing 14 and discharging the vaporized guest material to the outside of the apparatus, and opening the shutter 14 at the time when the sublimation of the host material begins, a mixture of the host material and the guest material will be vapor-deposited.

FIG. 8 is a plan view showing a concrete example of the organic EL element 9 produced by the above vacuum vapor deposition apparatus. That is,
On the glass substrate 6 having a size L of 30 mm × 30 mm, the ITO transparent electrode 5 having a size 1 of 2 mm × 2 mm is vapor-deposited by the above-described vacuum vapor deposition device to a thickness of about 100 nm, and then SiO ₂ 30 is vapor-deposited on the entire surface. Are etched into a predetermined pixel pattern to form a large number of openings 31, and the transparent electrodes 5 are exposed here. Therefore, the organic layers 4 and 3 and the aluminum electrode 1 are sequentially formed on the light emitting region (pixel) PX of 2 mm × 2 mm of SiO ₂ by using the vapor deposition mask 22. For the light emitting layer 3, the shutter 14 described above may be used together.

In this vacuum vapor deposition apparatus 11, in addition to the one having a large number of pixels as shown in FIG. 8 described above, it is also possible to independently form a large pixel.

In FIG. 9, the light emitting layer as shown in FIG. 1 is formed using Alq ₃ (host material) and DCM (guest material) as described above by the above-described vacuum vapor deposition apparatus. is a graph showing the spectral characteristics of the Alq ₃ and DCM.

According to this, in the layer structure of the light emitting layer 3, first, DCM having a low sublimation temperature is sublimated and vapor-deposited, and DC
A layer of M main component is formed in a vapor deposition thickness range of 0 to 30 nm, and subsequently Alq ₃ having a high sublimation temperature is sublimated and vapor deposited,
A layer containing Alq _{3 as} a main component is formed at a vapor deposition film thickness of 60 to 90 nm. That is, when the vapor deposition thickness is 60 to 90 nm, it can be considered that DCM has almost sublimated and Alq ₃ is close to 100%.

As a result, in the case of DCM, the film thickness is 0 to 30 nm.
Shows a high absorbance and shows an absorption peak at a wavelength of around 500 nm.

On the other hand, in the case of Alq ₃ , the film thickness is 60 to 90 nm.
In ((thickness when vapor-deposited with the shutter kept open)), the absorbance is high and an absorption peak is shown near the wavelength of 400 nm.

FIG. 10 shows details of the spectral characteristics of the DCM in FIG. 9 and shows the spectral characteristics for each thickness of 10 nm. According to this, DCM is first sublimated and vapor-deposited, and the film thickness in the vicinity of the interface with the hole transport layer (see FIG. 1) is 0 to
Characteristic curve 15a at 10 nm, characteristic curve 15b at film thickness 10 to 20 nm, characteristic curve 15c at film thickness 20 to 30 nm
As shown in, 450 to 500 nm when the film thickness is 0 to 30 nm
Shows an absorption peak at the wavelength of
It can be seen that CM is the main component.

FIG. 11 is a graph showing the threshold voltage characteristics of the organic EL element 21 having the above structure. As shown in the figure, almost no current flows until the voltage reaches about 10V, and it gradually starts to flow after 10V, and starts to flow rapidly after 15V. That is, it shows that the threshold voltage characteristics are good.

FIG. 12 shows the organic EL device shown in FIG.
21 shows the change of the emission wavelength with respect to the applied voltage between both electrodes 1-5 on the chromaticity coordinates. That is, the emission R _{1 that} is colored red (R) in the red region shifts to the short wavelength side as the applied voltage increases, the chromaticity of the spectrum changes to the emission R ₂ , and further the emission spectrum to the emission R _3. The chromaticity of has changed, indicating that it has approached orange.

This is due to the fact that the element 25
In, the emission center (recombination center) shifts from the anode side to the cathode side, that is, the emission center shifts from the long wavelength side by DCM to the short wavelength side by Alq ₃ , and R ₃
Since the green color of Alq ₃ is added at the light emitting position of, it is remarkable that the color is approaching from red to orange as a whole.

Next, a method for manufacturing the organic EL element 21 according to this embodiment described above will be described.

First, a cell for manufacturing an organic electroluminescence device in which a portion other than a 2 mm × 2 mm light emitting region is masked by SiO ₂ vapor deposition on an ITO transparent electrode 5 provided on a 30 mm × 30 mm glass substrate 6 with a film thickness of about 100 nm. To make.

Next, this cell was placed in the vacuum vapor deposition apparatus shown in FIG. 7, and TPD (N, N'-diphenyl-N, N'-di (3-methylphenyl) 4,4 'was used using a vapor deposition mask.
-Diaminobiphenyl) under vacuum by vacuum evaporation
The hole transport layer 4 is produced by vapor deposition (deposition rate: 2 to 4Å / sec) to a thickness of 50 nm.

Then, for the host-guest light-emitting layer, the host material is aluminum-quinoline complex A.
lq ₃ (tris (8-quinolinol) aluminum) is used, and DCM that is generally used as a laser dye is used as a guest material whose sublimation temperature is lower than that of the host material.
The composition ratio of Alq ₃ / DCM = 6/1 in weight ratio is set separately in the Ta vapor deposition boats 32 of FIGS. 2 and 3 and set in the vapor deposition apparatus 11.

Then, the above-deposited hole transport layer 4
First, the host-guest light emitting material is deposited as the layers 3c and 3b to a thickness of about 30 nm (deposition rate 2 to 4 Å / sec), and then the shutter 14 is closed to keep the deposition rate constant for 30 nm. Sublimate. After that, the shutter 14 is opened again, vapor deposition is performed to a thickness of 20 nm to form the light emitting layer 3c, and the host-guest light emitting layer 3 is manufactured so that the total film thickness becomes 50 nm.

As described above, this results in FIG.
As shown in Fig. 3, as the first vapor-deposited layer having a thickness of 30 nm, the layer 3c mainly composed of DCM by DCM having a low sublimation temperature, and subsequently Alq ₃ having a high sublimation temperature also started to sublimate and were mixed with each other.
A lq ₃ + DCM mixed layer 3b is formed. And the thickness
By sublimation by air for 30 nm, most of the DCM disappears, and a layer 3a containing Alq _{3 as a} main component is formed during the final vapor deposition with a thickness of 20 nm.

After that, aluminum is vapor-deposited as a cathode electrode to a thickness of about 2 kÅ (deposition rate 11 to 13 Å / sec) to form the metal electrode 1, and the organic electroluminescent device 21 is manufactured.

When the characteristics of the organic electroluminescent red light emitting device thus produced were measured, the maximum emission wavelength at an applied voltage of 8 V was 650 nm, and it is clear from the shape of the spectrum that DCM is the emission center. . Also, a brightness of about 1200 cd / m ² could be obtained for an applied voltage of 15V.

A characteristic of this element is that DC measured specifically at the interface with the hole transport layer 4 from the measurement results of the spectrum.
It is clear that M forms a light-emitting layer doped in Alq ₃ , and as the applied voltage increases, the chromaticity of the emission spectrum shows the green emission which is the emission of Alq ₃ on the CIE chromaticity coordinate. It is considered that the components increased, and as a result, the color became closer to orange (see Fig. 12).

It is considered that this is because the recombination center of electrons and holes contributing to light emission was shifted from the interface between the hole transport layer 4 and the light emitting layer to the cathode electrode side as the applied voltage was increased. To be Therefore, it is considered that this element has a feature that it is a light emitting element whose chromaticity changes from red light emission to orange light emission in accordance with the applied voltage.

According to this embodiment, since the sublimation temperature of the host material is higher than the sublimation temperature of the guest material, a portion having a high guest material content and a portion having a high host material content are formed in the formed amorphous light-emitting layer. Is formed as the vapor deposition progresses, the portion having a high content of the host material also serves as the electron transport layer, and the portion having a high content of the guest material can generate specific light emission. Therefore, a single element can emit light with high brightness and which can be modulated by the guest material.

In addition, since it is possible to easily and continuously perform vapor deposition in one vacuum vapor deposition apparatus by using one vapor deposition boat 32 in a consistent vacuum process, the conventional vacuum vapor deposition apparatus can be used. Without particular modification, the host material and the guest material can be arranged at arbitrary positions in the stacking direction of the light emitting layer, and the concentration gradient of the guest material can also be arbitrarily controlled, so that organic EL devices having various device structures can be manufactured. it can.

As a result, a light emitting element whose emission wavelength changes with an increase in applied voltage is produced, and emission wavelengths of various emission colors and luminances can be stably produced. As for other luminescent colors (G, B), it is needless to say that a luminescent layer can be formed in the same manner as the above red (R) to produce a full-color or multi-color element of three primary colors of R, G, B. (The same applies below).

The above-described effects of this embodiment can be similarly obtained in other embodiments described later.

Contrary to the manufacturing method of this embodiment, conventionally, the vacuum evaporation method is often used in the process of manufacturing the organic electroluminescent device, and the guest molecules are binary-deposited together with the host material in the vacuum integrated process. At least two vapor deposition sources are required for this, and considering that an organic electroluminescent device is formed by stacking an electron transport layer, a hole transport layer, and a cathode electrode, many vapor deposition sources can be used to prepare a vapor deposition machine. There is a need to.

In the application to the full-color display, considering that the electron transport layer, the hole transport layer, and the cathode electrode are made of the same material, the three primary colors of R, G, and B are considered as the light emitting layer. , A total of 6 deposition sources (electron transport layer, hole transport layer, cathode electrode,
R, G, and B light emitting layers) are required. This indicates that it is difficult to make a full color display with a vacuum integrated process.

FIG. 13 shows an organic EL element according to the second embodiment of the present invention, (a) is a sectional view of the essential part,
(B) is an enlarged view of the B portion of (a).

In this example, the host-guest light-emitting layer was formed by using Alq ₃ (tris (8-quinolinol) aluminum), which is an aluminum-quinoline complex, as the host material, and the sublimation temperature was lower than that of the host material. Nile Red (manufactured by Lambda Physik)
14) to produce a red light emitting device. Alq ₃ / Nile Red = 5/1 composition ratio by weight ratio is divided and placed in a Ta vapor deposition boat to form a light emitting layer material.

On the transparent electrode 5 formed in the same manner as in the first embodiment described above, TPD (N,
N'-diphenyl-N, N'-di (3-methylphenyl) 4,4'-diaminobiphenyl) was vapor-deposited by vacuum vapor deposition under vacuum to a thickness of about 50 nm (deposition rate 2-4Å / se).
Then, the hole transport layer 4 is formed.

Then, on the vapor-deposited hole transport layer 4, layers 3e and 3d as host-guest light-emitting layers were first vapor-deposited to a thickness of approximately 35 nm (vapor deposition rate 2 to 4Å / sec), and then the shutter was released. 14 is closed, and 30 nm is sublimated by air while keeping the deposition rate constant. After that, the shutter 14 is opened again, the layer 3a is formed by vapor deposition to a thickness of 15 nm, and the host-guest light emitting layer 3 is prepared so that the total film thickness becomes 50 nm.

As a result, as shown in FIG. 13 (b), Nile R having a low sublimation temperature was used as the first vapor deposition layer having a thickness of 35 nm.
A layer 3e of the Nile Red main component by ed, and subsequently Alq ₃ having a high sublimation temperature also starts to sublime and is mixed Alq _{3.
A 3} + Nile Red mixed layer 3d is formed. And the thickness
Nile Red almost disappears by the sublimation for 30 nm, and the layer 3a mainly composed of Alq ₃ is formed by the final vapor deposition with a thickness of 15 nm. After that, aluminum is vapor-deposited as a cathode electrode to a thickness of about 2 kÅ (deposition rate 11 to 13 Å / sec) to form the metal electrode 1, and the organic electroluminescent element 22 is manufactured.

When the characteristics of the organic electroluminescent red light emitting device thus produced were measured, the maximum emission wavelength at an applied voltage of 9 V was 615 nm, and the Nile Red was determined from the shape of the spectrum.
It is clear that is the emission center. Also, 15
It was possible to obtain a brightness of about 700 cd / m ^{2 with} respect to an applied voltage of V.

As a characteristic of this element, the Nile is peculiar to the interface with the hole transport layer 4 from the measurement result of the spectrum.
It is clear that Red forms a light emitting layer doped in Alq ₃ , and as the applied voltage is increased, the chromaticity of the emission spectrum is green, which is the light emission of Alq ₃ on the CIE chromaticity coordinate. It is considered that the components increased, and as a result, the color approached orange.

It is considered that this is because the recombination center of electrons and holes that contribute to light emission shifts from the interface between the hole transport layer 4 and the light emitting layer to the cathode electrode side as the applied voltage increases. To be Therefore, this element is considered to have a feature of being a light emitting element whose chromaticity changes from red light emission to orange light emission.

FIG. 15 shows an organic EL element according to the third embodiment of the present invention, (a) is a sectional view of the essential part,
(B) is an enlarged view of the C portion of (a).

In this example, a gallium-quinoline complex, Gaq ₃ (tris (8-quinolinol) gallium) was used as the host material in the host-guest light-emitting layer, and the guest material had a sublimation temperature lower than that of the host material. DCM which is generally used as a laser dye for
A red light emitting element is manufactured. G by weight ratio to Ta deposition boat
Separated at a composition ratio of aq ₃ / DCM = 6/1, they are used as light emitting layer materials.

Next, the TPD is formed on the transparent electrode 5 formed in the same manner as in the first embodiment described above by the same method as in the first embodiment.
(N, N'-diphenyl-N, N'-di (3-methylphenyl) 4,4'-diaminobiphenyl) was vapor-deposited under vacuum to a thickness of about 50 nm (deposition rate 2 to 4Å).
/ sec), and the hole transport layer 4 is formed.

On the vapor-deposited hole transport layer 4, as the host-guest light-emitting layer, the layers 3c and 3g were first deposited to about 30.
After vapor deposition to a thickness of nm (vapor deposition rate of 2 to 4Å / sec), the shutter 14 is closed, and 30 nm is sublimated by air while keeping the vapor deposition rate constant. After that, the shutter 14 is opened again, the layer 3f is formed by vapor deposition to a thickness of 20 nm, and the host-guest light emitting layer 3 is manufactured so that the total film thickness becomes 50 nm.

As a result, as shown in FIG. 15B, as the first vapor-deposited layer having a thickness of 30 nm, the layer 3c mainly composed of DCM made of DCM having a low sublimation temperature and then G having a high sublimation temperature were used.
Gaq ₃ + DC where aq ₃ also started to sublimate and both were mixed
An M mixed layer 3g is formed. Then, by sublimation by air having a thickness of 30 nm, most of the DCM disappears, and by the final vapor deposition having a thickness of 20 nm, a layer 3f mainly composed of Gaq ₃ is formed.

After that, aluminum is vapor-deposited as a cathode electrode to a thickness of about 2 kÅ (deposition rate: 11 to 13 Å / sec) to form the metal electrode 1, and the organic electroluminescent element 23 is manufactured.

When the characteristics of the organic electroluminescent red light emitting device thus produced were measured, the maximum emission wavelength at an applied voltage of 8 V was 650 nm, and it is clear from the shape of the spectrum that DCM is the emission center. . Also, a brightness of about 1400 cd / m ² could be obtained for an applied voltage of 15V.

A characteristic of this element is that DC measured specifically at the interface with the hole transport layer 4 from the measurement results of the spectrum.
It is clear that M forms a light-emitting layer doped in Gaq ₃ , and as the applied voltage increases, the chromaticity of the emission spectrum becomes green, which is the emission of Gaq ₃ on the CIE chromaticity coordinates. It is considered that the components increased, and as a result, the color approached orange.

It is considered that this is because the recombination center of electrons and holes contributing to light emission was shifted from the interface between the hole transport layer 4 and the light emitting layer to the cathode electrode side as the applied voltage was increased. To be

FIG. 16 shows an organic EL device according to a fourth embodiment of the present invention, FIG. 16 (a) is a sectional view of the essential part,
(B) is an enlarged view of a D part of (a).

In this example, as the host-guest light-emitting layer, gallium-quinoline complex Gaq ₃ (tris (8-quinolinol) gallium) was used as the host material, and the sublimation temperature was lower than that of the host material. Nile, which is commonly used as a laser dye in guest materials
A red light emitting element is manufactured using Red. Separately placed in a Ta vapor deposition boat at a composition ratio of Gaq ₃ / Nile Red = 6/1 by weight to be used as a light emitting layer material.

Next, the TPD is formed on the transparent electrode 5 formed in the same manner as in the first embodiment described above by the same method as in the first embodiment.
(N, N'-diphenyl-N, N'-di (3-methylphenyl) 4,4'-diaminobiphenyl) was vapor-deposited under vacuum to a thickness of about 50 nm (deposition rate 2 to 4Å).
/ sec), and the hole transport layer 4 is formed.

Then, layers 3e and 3h were first deposited as a host-guest light emitting layer on the vapor-deposited hole transport layer 4 to a thickness of about 30 nm (deposition rate 2 to 4Å / sec), and then the shutter 14 was pressed. , And sublimate 30 nm by air while keeping the deposition rate constant. Then, the shutter 14 is opened again, and the layer 3f is formed by vapor deposition to a thickness of 20 nm.
Host-guest light emitting layer 3 so that the total film thickness becomes 50 nm
Is prepared.

As a result, as shown in FIG. 16 (b), Nile R having a low sublimation temperature was used as the vapor deposition layer having an initial thickness of 30 nm.
Nile Red main component layer 3e by ed, and then Gaq ₃ in which both Gaq ₃ having a high sublimation temperature starts to sublimate and Gaq ₃ is mixed.
_{A 3} + Nile Red mixed layer 3h is formed. And the thickness
Nile Red almost disappears by the sublimation for 30 nm, and the layer 3f mainly composed of Gaq ₃ is formed by the final vapor deposition with a thickness of 20 nm.

After that, aluminum is vapor-deposited as a cathode electrode to a thickness of about 2 kÅ (deposition rate: 11 to 13 Å / sec) to form the metal electrode 1, and the organic electroluminescent element 24 is manufactured.

When the characteristics of the organic electroluminescent red light emitting device thus produced were measured, the maximum light emission wavelength at an applied voltage of 8 V was 615 nm, and the Nile Red was determined from the shape of the spectrum.
It is clear that is the emission center. Also, 15
It was possible to obtain a brightness of about 1300 cd / m ^{2 with} respect to an applied voltage of V.

As a feature of this element, the Nil was specifically determined at the interface with the hole transport layer 4 from the measurement result of the spectrum.
It is clear that e Red forms a light emitting layer doped in Gaq ₃ , and as the applied voltage increases, the chromaticity of the emission spectrum is green which is the emission of Gaq ₃ on the CIE chromaticity coordinates. It is considered that the component of was increased, and as a result, it became closer to orange.

It is considered that this is because the recombination center of electrons and holes contributing to light emission was shifted from the interface between the hole transport layer 4 and the light emitting layer to the cathode electrode side as the applied voltage was increased. .

FIG. 17 shows an organic EL device according to a fifth embodiment of the present invention, wherein (a) is a sectional view of the main part thereof,
(B) is an enlarged view of the E portion of (a).

In this example, as the host-guest light emitting layer, Alq ₃ (tris (8-quinolinol) aluminum), which is an aluminum-quinoline complex, was used as the host material, and the guest material having a sublimation temperature lower than that of the host material was used. Commonly used as a laser dye in DC
Using M, a red light emitting element is manufactured. Alq ₃ / DCM = 6/1 composition ratio by weight ratio is separately set in a Ta vapor deposition boat to form a light emitting layer material.

Next, TP is formed on the transparent electrode 5 formed in the same manner as in the first embodiment described above by the same method as in the first embodiment.
D (N, N'-diphenyl-N, N'-di (3-methylphenyl) 4,4'-diaminobiphenyl) was vapor-deposited under vacuum to a thickness of about 50 nm by a vacuum vapor deposition method (deposition rate 2 to 4).
Å / sec) to form the hole transport layer 4.

Then, only Alq ₃ is vapor-deposited as a layer 3 a ′ having a thickness of 10 nm on the vapor-deposited hole transport layer 4. Layers 3c and 3d were formed as a host-guest light emitting layer on the Alq ₃ layer with a thickness of about 30 nm (deposition rate: 2 to 4Å / s).
After vapor deposition on ec), the shutter 14 is closed and the vapor deposition rate is kept constant and 30 nm is sublimated. After that, the shutter 14 is opened again, and the layer 3a is formed by vapor deposition to a thickness of 10 nm, and Alq ₃ + is formed so that the total film thickness becomes 50 nm.
A host-guest light emitting layer 3 is prepared. That is, this light emitting layer alone has a four-layer structure.

In this case, as shown in FIG. 17B, first, from the container containing only Alq ₃ (or, in the vapor deposition boat 32 shown in FIGS. 2 and 3, only the vapor outflow hole 38 is appropriately shielded. (By closing by means) sublimate Alq _3
3 After forming the main component layer 3a ′, using the container Ta vapor deposition boat 32 as shown in FIGS. 2 and 3, a DCM main component layer 3 of DCM having a low sublimation temperature was used as a vapor deposition layer having a thickness of 30 nm.
c, and subsequently, Alq ₃ having a high sublimation temperature is sublimated to form an Alq ₃ + DCM mixed layer 3b in which both are mixed. Then, by sublimation by air having a thickness of 30 nm, most of the DCM disappears, and by the final vapor deposition having a thickness of 10 nm, a layer 3a mainly composed of Alq ₃ is formed.

After that, aluminum is vapor-deposited as a cathode electrode to a thickness of about 2 kÅ (deposition rate: 11 to 13 Å / sec) to form the metal electrode 1, and the organic electroluminescent element 25 is manufactured.

When the characteristics of the organic electroluminescent red light-emitting device thus produced were measured, the maximum emission wavelength at an applied voltage of 15 V was 650 nm, and it is clear from the shape of the spectrum that DCM is the emission center. . In addition, a brightness of about 900 cd / m ² could be obtained for an applied voltage of 15V.

A characteristic of this element is that a light emitting layer in which DCM is specifically doped in Alq ₃ is formed in the central portion of the light emitting layer 3 in the stacking direction from the measurement result of the spectrum. Therefore, as the applied voltage increases, the chromaticity of the emission spectrum becomes Alq on the CIE chromaticity coordinate.
It is considered that the components from green, which is the light emission of ₃ , to red, which is the light emission of DCM, increased, and as a result, passed from light green to orange and then approached red.

It is considered that this is because the recombination center of electrons and holes contributing to light emission was shifted from the interface between the hole transport layer 4 and the light emitting layer 3 to the cathode electrode side as the applied voltage was increased. To be Therefore, it is considered that this element has a structure of a light emitting layer capable of obtaining red light emission with high brightness at high applied voltage.

FIG. 18 shows an organic EL device according to a sixth embodiment of the present invention, in which (a) is a cross-sectional view of its essential part.
(B) is an enlarged view of the lower part of (a).

In this example, as the host-guest light emitting layer, Alq ₃ (tris (8-quinolinol) aluminum), which is an aluminum-quinoline complex, was used as the host material, and the guest material having a sublimation temperature lower than that of the host material was used. C540 (coumarin 540) (see FIG. 19 for the structural formula) is used to manufacture a green light emitting device. Alq ₃ / C 540 = 7/1 composition ratio by weight is divided and placed in a Ta vapor deposition boat to form a light emitting layer material.

Next, TP is formed on the transparent electrode 5 formed in the same manner as in the first embodiment described above by the same method as in the first embodiment.
D (N, N'-diphenyl-N, N'-di (3-methylphenyl) 4,4'-diaminobiphenyl) was vapor-deposited under vacuum to a thickness of about 50 nm by a vacuum vapor deposition method (deposition rate 2 to 4).
Å / sec) to form the hole transport layer 4.

Then, on the vapor-deposited hole transport layer 4, layers 3j and 3i as host-guest light-emitting layers were first vapor-deposited to a thickness of about 35 nm (vapor deposition rate 2 to 4Å / sec), and then the shutter was released. 14 is closed, and 30 nm is sublimated by air while keeping the deposition rate constant. After that, the shutter 14 is opened again, and vapor deposition is performed to a thickness of 15 nm to form the layer 3a,
Host-guest light emitting layer 3 so that the total film thickness becomes 50 nm
Is prepared.

As a result, as shown in FIG. 18 (b), a coumarin C540-based layer 3j of coumarin C540 having a low sublimation temperature was used as the first vapor-deposited layer having a thickness of 35 nm.
Alq ₃ having a high sublimation temperature sublimates and is mixed A
The lq ₃ + coumarin C 540 mixed layer 3i is formed. Then, the coumarin C540 almost disappears by the sublimation having a thickness of 30 nm, and the layer 3a containing Alq _{3 as a} main component is formed by the final vapor deposition having a thickness of 15 nm.

After that, aluminum is vapor-deposited as a cathode electrode to a thickness of about 2 kÅ (deposition rate: 11 to 13 Å / sec) to form the metal electrode 1, and the organic electroluminescent element 26 is manufactured.

When the characteristics of the organic electroluminescent red light emitting device thus produced were measured, the maximum emission wavelength at an applied voltage of 9 V was 535 nm, and it is clear from the shape of the spectrum that C540 is the emission center. . Further, a brightness of about 1150 cd / m ² could be obtained for an applied voltage of 15V.

As a feature of this device, from the measurement result of the spectral spectrum, C54 was found specifically at the interface with the hole transport layer 4.
0 is clear that to form a light emitting layer doped into the Alq _3, and the long wavelength is C540 an emission wavelength of maximum emission wavelength 520nm around exhibiting Alq ₃ originally, CIE
As a result, the chromaticity on the chromaticity coordinates is improved.

20A and 20B show an organic EL device according to a seventh embodiment of the present invention. FIG. 20A is a sectional view of a main part thereof, and FIG. 20B is an enlarged view of a G part of FIG. 20A.

In this embodiment, TPD (N, N'-diphenyl-N, N'-di (3-methylphenyl) 4,4'- was used as the host material for the host-guest light emitting layer.
Using diaminobiphenyl) and C450 (coumarin 450) (see FIG. 21 for the structural formula) as a guest material having a higher sublimation temperature than the host material, a blue light emitting element is manufactured. The TPD / C450 = 5/1 composition ratio by weight is divided and placed in a Ta vapor deposition boat to form a light emitting layer material.

Next, unlike the above-mentioned respective embodiments, the hole-transporting host-guest was formed on the transparent electrode 5 formed in the same manner as in the above-mentioned first embodiment by the same method as in the first embodiment. First, the light emitting layers 3m and 3l were formed to a thickness of about 35 nm (deposition rate 2
After vapor deposition at ~ 4Å / sec), the shutter 14 is closed and the vapor deposition rate is kept constant to sublimate 30 nm.

After that, the shutter 14 is opened again, the layer 3k is formed by vapor deposition to a thickness of 15 nm, and the host-guest light emitting layer 3 is prepared so that the total film thickness becomes 50 nm. Next, dimethyl bathophenanthroline is vapor-deposited by vacuum vapor deposition under vacuum to a thickness of about 50 nm (vapor deposition rate 2 to 4Å / sec) to form the electron transport layer 2.

As a result, as shown in FIG. 20 (b), as a vapor deposition layer having an initial thickness of 35 nm, a layer 3m of a TPD main component made of TPD, which is a host material having a low sublimation temperature, and subsequently a guest having a high sublimation temperature are used. Coumarin C450 as a material is sublimated to form TPD + coumarin C450 mixed layer 3l in which both are mixed. Almost all TPD disappeared by 30nm-thick air sublimation, and coumarin C45 was formed by the final vapor deposition of 15nm.
0 A layer 3k of the main component is formed.

Thereafter, aluminum is vapor-deposited as a cathode electrode to a thickness of about 2 kÅ (deposition rate: 11 to 13 Å / sec) to form the metal electrode 1, and the organic electroluminescence device 27 for blue color is formed.
Is prepared.

When the characteristics of the organic electroluminescent blue light emitting device thus produced were measured, the maximum emission wavelength at an applied voltage of 12 V was 445 nm, and it is clear from the shape of the spectrum that C450 is the emission center. . Further, it was possible to obtain a brightness of about 400 cd / m ² for an applied voltage of 18V.

As a characteristic of this device, the coumarin C450 was specifically doped on the layer 3m side between the dimethylbasophenanthroline layer 2 and the layer 3m containing TPD also serving as a hole transport layer as a characteristic of this element. It is clear that the formed light emitting layer 3l is formed, and this shortens the emission wavelength (bluish).

Although the embodiments of the present invention have been described above, the above-described embodiments can be variously modified based on the technical idea of the present invention.

For example, in the above-described light emitting material, the guest material may be any material that has a sublimation property, and is not limited to a fluorescent dye. For example,
A pigment such as quinacridone may be used, and a host material suitable for the pigment may be selected according to the purpose.

Further, in the above-mentioned embodiment, C450 (coumarin 450) was used for blue, but for red,
C445 (coumarin 445) or C540 (coumarin 540) may be used, or a plurality of them may be mixed. Further, co-evaporation of DCM and coumarin may be used. In this case, the host material is PTP (p-Ter) having a shorter fluorescence wavelength than C450.
phenyl), PQP (p-Quaterphenyl), QUI, BBQ
A laser dye such as (BiBuQ) or t-butyl-PBD may be used.

As for the method of manufacturing the light emitting layer, for example, in order to dope at an arbitrary portion in the stacking direction, the deposition order may be devised in consideration of the combination of the host-guest material. Further, in order to control the concentration gradient of the guest material in the doped portion, the vapor deposition rate may be changed. Further, the light emitting layer can be formed by another film forming method involving sublimation or vaporization other than vapor deposition. The light emitting layer may have a single hetero structure or a double hetero structure (see FIG. 20).

The materials for the anode electrode, the electron transport layer, the hole transport layer, the cathode electrode, etc. are not limited to the above.
For example, in the case of a hole transport layer, a benzidine derivative,
A hole transporting organic substance such as a styrylamine derivative, a triphenylmethane derivative or a hydrazone derivative may be used. Similarly, an electron transporting organic substance such as a perylene derivative, a bisstyryl derivative, or a pyrazine derivative may be used for the electron transporting layer.

As 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 aluminum, for example, indium, magnesium,
A low work function metal such as silver, calcium, barium or lithium may be used alone or as an alloy with another metal to improve stability.

In addition, in order to take out organic electroluminescence from the anode electrode side, ITO which is a transparent electrode is used as the anode electrode.
In order to efficiently inject holes, an electrode having a large work function from the vacuum level of the anode electrode material, for example, an electrode of gold, tin dioxide-antimony mixture, zinc oxide-aluminum mixture may be used. .

In the above-described embodiments, the mono-color organic EL has been mainly described. However, by selecting a light-emitting material, a full-color or multi-color light emitting three colors R, G and B can be emitted. The organic EL element can be manufactured by the method described above. In addition, the present invention can be applied not only to an organic EL element that can be used not only for a display but also for a light source, and can also be applied to other optical uses.

[0156]

As described above, according to the present invention, at least a part of the light emitting region contains the first light emitting material and the second light emitting material, and the light emitting wavelengths of these light emitting materials are different from each other. One luminescent material has a higher (or lower) vaporization temperature than the second luminescent material, and
Since it has at least an electron transporting property (or a hole transporting property) out of the electron transporting property and the hole transporting property, the content rate of the first or second light emitting material is appropriately changed or distributed at the time of forming the light emitting region. It is possible to provide an optical element such as a tunable light emitting element in which the light emitting wavelength changes according to the applied voltage and various light emitting wavelengths can be obtained by one element.

Moreover, since the first light emitting material and the second light emitting material having different vaporization temperatures are vaporized to form the light emitting region, the optical element of the present invention can be relatively easily manufactured by using the conventional device. It is possible to make.

[Brief description of drawings]

FIG. 1 shows an organic EL device according to a first embodiment of the present invention, where (a) is a sectional view of a main part, (b) is an enlarged view of part A of (a), and (c) is the same part A. It is an enlarged view which made other composition.

FIG. 2 is a sectional view of a vapor deposition boat according to the same embodiment.

FIG. 3 is an exploded perspective view of FIG. 2;

FIG. 4 is a structural formula of Alq ₃ (host material) used in the same example.

FIG. 5 is a structural formula of DCM (guest material) used in the same example.

FIG. 6 is a TPD (hole transport material) used in the example.
Is the structural formula of.

FIG. 7 is a schematic cross-sectional view of a vacuum vapor deposition device used in the example.

FIG. 8 is a plan view of an organic EL element according to the same example.

FIG. 9 is a graph showing spectral characteristics of Alq ₃ and DCM according to the example.

10 is a graph showing details of spectral characteristics of DCM in FIG. 9.

FIG. 11 is a graph showing threshold voltage characteristics of the organic EL element according to the same example.

FIG. 12 is a chromaticity coordinate diagram of the organic EL element according to the example.

FIG. 13 shows an organic EL device according to a second embodiment of the present invention, (a) is a cross-sectional view of a main part, and (b) is an enlarged view of a B part of (a).

[FIG. 14] Nile Red (guest material) used in the example
Is the structural formula of.

FIG. 15 shows an organic EL device according to a third embodiment of the present invention, (a) is a cross-sectional view of a main part, and (b) is an enlarged view of a C part of (a).

FIG. 16 shows an organic EL device according to a fourth embodiment of the present invention, (a) is a cross-sectional view of a main part, and (b) is an enlarged view of a D part of (a).

FIG. 17 shows an organic EL device according to a fifth embodiment of the present invention, (a) is a cross-sectional view of a main part, and (b) is an enlarged view of an E part of (a).

FIG. 18 shows an organic EL device according to a sixth embodiment of the present invention, (a) is a cross-sectional view of a main part, and (b) is an enlarged view of an F part of (a).

FIG. 19 is a structural formula of C540 (coumarin 540) (guest material) used in the same example.

FIG. 20 shows an organic EL device according to a seventh embodiment of the present invention, (a) is a cross-sectional view of a main part, and (b) is an enlarged view of a G part of (a).

FIG. 21 is a structural formula of C450 (coumarin 450) (guest material) used in the same example.

FIG. 22 is a schematic cross-sectional view showing an example of a conventional organic EL element.

FIG. 23 is a schematic cross-sectional view showing an example of another organic EL element.

FIG. 24 is a schematic perspective view showing a specific example of the same organic EL element.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Metal electrode (cathode), 2 ... Electron transport layer, 3 ... Light emitting layer, 3a ... Layer of Alq ₃ main component, 3b ... Alq ₃ + DC
M mixed layer, 3c ... DCM main component layer, 3d ... Alq ₃ +
Nile Red mixed layer, 3e ... Nile Red main component layer, 3f
... Gaq ₃ main component layer, 3 g ... Gaq ₃ + DCM mixed layer, 3 h ... Gaq ₃ + Nile Red mixed layer, ₃ i ... Alq
₃ + C540 mixed layer, 3j ... C540 Main component layer, 3k ... C
450 Main component layer, 3l ... TPD + C450 mixed layer, 3m ...
TPD main component layer, 4 ... Hole transport layer, 5 ... ITO transparent electrode (anode), 6 ... Glass substrate, 10, 20, 21, 22,
23, 24, 25, 26, 27 ... Organic EL element, 11 ... Vacuum deposition apparatus, 13 ... Supporting means, 14 ... Shutter, 28, 32 ... Deposition source,
32 ... evaporation boat (deposition source), 33 ... upper lid, 34 ... inner lid, 35a
... first storage tank, 35b ... second storage tank, 36 ... partition plate, 37, 3
8, 39 ... Steam outflow hole, PX ... Pixel

Claims (21)

[Claims] 1. An optical element in which an organic layer including a light emitting region is provided on an electrode, at least a part of the light emitting region contains a first light emitting material and a second light emitting material, and these light emitting regions emit light. The emission wavelengths of the materials are different from each other, the first light emitting material has a higher vaporization temperature than the second light emitting material, and has at least an electron transporting property out of an electron transporting property and a hole transporting property. Optical element. 2. An optical element in which an organic layer including a light emitting region is provided on an electrode, part of the light emitting region contains a first light emitting material and a second light emitting material, and these light emitting materials are included. Have different emission wavelengths from each other, the first light-emitting material has a higher vaporization temperature than the second light-emitting material, and has at least an electron-transporting property among an electron-transporting property and a hole-transporting property, An optical element in which another light emitting portion containing the first light emitting material or the second light emitting material as a main component is adjacently provided below or above the part of the light emitting region. 3. An optical element in which an organic layer including a light emitting region is provided on an electrode, at least a part of the light emitting region contains a first light emitting material and a second light emitting material, and these light emitting devices emit light. The light emission wavelengths of the materials are different from each other, the first light emitting material has a lower vaporization temperature than the second light emitting material, and has at least a hole transporting property of a hole transporting property and an electron transporting property. Optical element. 4. An optical element in which an organic layer including a light emitting region is provided on an electrode, and a part of the light emitting region contains a first light emitting material and a second light emitting material, and these light emitting materials are included. Have different emission wavelengths from each other, the first light-emitting material has a lower vaporization temperature than the second light-emitting material, and has at least a hole-transporting property and an electron-transporting property, An optical element in which another light emitting portion containing the first light emitting material or the second light emitting material as a main component is adjacently provided below or above the part of the light emitting region. 5. The optical element according to claim 1, wherein the content of the second light emitting material is controlled in the light emitting region. 6. The optical element according to claim 1, wherein the content of the second light emitting region material has a concentration gradient in the thickness direction in the light emitting region. 7. The first light emitting material is dispersed in the light emitting region at an arbitrary position in the thickness direction thereof.
4. The optical element according to any one of 4 above. 8. The optical element according to claim 1, wherein the chromaticity of its emission spectrum changes in response to an applied voltage. 9. A transparent electrode, an organic hole transport layer, an organic light emitting layer and / or an organic electron transport layer, and a metal electrode are laminated on an optically transparent substrate. The optical element according to item 1. 10. The optical element according to claim 9, which is configured as an organic electroluminescent element. 11. The optical element according to claim 10, which is configured as an element for a color display. 12. An electrode comprising a first light emitting material and a second light emitting material having different light emitting wavelengths vaporized, and a light emitting region having a light emitting portion containing these light emitting materials in at least a part thereof as at least a part of an organic layer. In forming the above, as the first light emitting material, a light emitting material having a higher vaporization temperature than the second light emitting material and having at least an electron transporting property of an electron transporting property and a hole transporting property is used. A method for manufacturing an optical element. 13. A vaporizing at least one of a first light emitting material and a second light emitting material having emission wavelengths different from each other, thereby adjoining a light emitting portion containing these light emitting materials and a light emitting portion below or above the light emitting portion. When forming the above-mentioned first light-emitting material or another light-emitting portion containing the second light-emitting material as a main component on the electrode as at least a part of the organic layer,
An optical element that uses, as the first light-emitting material, a light-emitting material that has a higher vaporization temperature than the second light-emitting material and that has at least an electron-transporting property among electron-transporting properties and hole-transporting properties. Production method. 14. A first light emitting material and a second light emitting material having different light emitting wavelengths are vaporized, and a light emitting region having a light emitting portion containing these light emitting materials in at least a part is used as at least a part of an organic layer as an electrode. In forming the above, as the first light emitting material, a light emitting material having a vaporization temperature lower than that of the second light emitting material and having at least hole transporting property among hole transporting property and electron transporting property is used. A method for manufacturing an optical element. 15. By vaporizing at least one of a first light emitting material and a second light emitting material having emission wavelengths different from each other, a light emitting portion containing these light emitting materials and a light emitting portion adjacent to below or above this light emitting portion are adjacent to each other. When forming the above-mentioned first light-emitting material or another light-emitting portion containing the second light-emitting material as a main component on the electrode as at least a part of the organic layer,
An optical element that uses, as the first light-emitting material, a light-emitting material that has a lower vaporization temperature than the second light-emitting material and that has at least a hole-transporting property among hole-transporting properties and electron-transporting properties. Production method. 16. The method according to claim 12, wherein the content of the second light emitting material is controlled in the light emitting region. 17. The method according to claim 12, wherein a concentration gradient is formed in the content of the second light emitting material in the thickness direction of the light emitting region. 18. The method according to claim 12, wherein the second light emitting material is dispersed in the light emitting region at any position in the thickness direction. 19. The transparent electrode, the organic hole transporting layer, the organic light emitting layer and / or the organic electron transporting layer, and the metal electrode are laminated on the optically transparent substrate, according to any one of claims 12 to 15. The method described. 20. The method according to claim 19, which is configured as an organic electroluminescent device. 21. The method according to claim 20, which is configured as a device for a color display.