JP2002164170A - White color organic electroluminescence panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a white color organic electroluminescence panel that has high efficiency and a long life. SOLUTION: This concerns a white color electroluminescence panel that is formed by holding an organic light-emitting material 3 between a positive electrode 1 and a negative electrode 2. Plural kinds of organic light-emitting material 3 having different light-emitting colors are arranged in parallel between the positive electrode 1 and negative electrode 2. At least one of the positive electrode 1 and the negative electrode 2 is formed by an electrode that is connected to the organic light-emitting material of all kinds, and the light-emitting drive of the organic light-emitting material 3 of all kinds is done by the power supply to the positive electrode 1 and the negative electrode 2 by one power supply system.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a white electroluminescent panel which can be used for a backlight for a liquid crystal display, a lighting device, and the like.

[0002]

2. Description of the Related Art Organic electroluminescent devices using an organic material as a luminous element have been attracting attention for a long time, and various studies have been conducted. Did not. However, 198
In 7 years, Kodak C.I. W. Tang et al. Proposed an organic electroluminescence having a function-separated stacked structure in which an organic material was divided into two layers, a hole transport layer and a light-emitting layer. In this case, despite the low voltage of 10 V or less,
It was found that a high emission luminance of 1000 cd / m ² or more was obtained. Since then, organic electroluminescence devices have begun to attract attention, and active research has been conducted.

As a result of such research and development, at present, organic electroluminescent devices can emit high-intensity surface light of about 100 to 100,000 cd / m ² at a low voltage of about 10 V, and the type of fluorescent substance can be changed. By making this selection, full color conversion from blue to red and white light emission are possible. And as practical application approaches,
Although blue and green materials have been developed with sufficient luminous efficiency and lifetime characteristics, further improvement in luminous efficiency and lifetime is desired for red and white light emitting devices. Under these circumstances, many reports have been made on white light emitting devices.

[0004] As a method of obtaining white light emission, generally,
There are a method using light emission from three wavelengths of R, G, and B, and a method using color development of two wavelengths having a complementary relationship of blue and yellow or blue-green and orange.

In the case of the three-wavelength method, p-Et
It has been reported that a TAZ (triazole derivative) carrier block layer was used to enable R, G, B three-wavelength white light emission, and even in a polymer system, an electron transport agent PBD (PVD) was used in PVK (polyvinyl carbazole). It has been reported that white light emission of 4000 cd / m ² was made possible by molecularly dispersing an oxadiazole derivative) and four kinds of dyes. However, these have low luminance efficiency characteristics compared to other luminescent colors, and cannot be said to be sufficient in terms of life characteristics from the viewpoint of practical use, and there are also problems such as color misregistration caused by different degradation behaviors of the three dyes. In addition, in the case of a low-molecular-weight system, there is a problem that the manufacturing process is complicated.

In the case of the two-wavelength method, a white element in which blue and orange dye doping layers are arranged on both sides of the recombination interface is used.
Maximum luminance 18000 cd / m ² , luminous efficiency 2.3 lm /
There is a report that W has been realized. In a device using a diphenylanthracene derivative as a blue material, 100
A white light element that achieves a luminous efficiency of 4 lm / W at 0 cd / m ² has been reported.

However, when considering differentiation from other types of displays such as LCDs (liquid crystal displays) and applications to full-color displays and lighting applications, the white organic electroluminescent panel requires even lower power consumption and higher power. Luminous efficiency needs to be improved. So far, approaches to improve quantum efficiency by increasing the quantum yield of fluorescence of organic light-emitting materials, and approaches to improving the light-emitting element structure to achieve low-voltage driving of the element, etc., have been conventionally used to increase the efficiency. Have been studied a lot, but there has been little study on improving the efficiency of the entire white organic electroluminescent panel device.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has as its object to provide a white organic electroluminescent panel capable of achieving high efficiency and a long life. is there.

[0009]

According to a first aspect of the present invention, there is provided a white organic electroluminescent panel formed by holding an organic light emitting material between an anode and a cathode. Anode 1
Kinds of organic luminescent materials 3 having different luminescent colors between the luminescent material and the cathode 2
Are arranged in parallel, at least one of the anode 1 and the cathode 2 is formed from electrodes connected to all kinds of organic light emitting materials 3, and power is supplied to the anode 1 and the cathode 2 by one power supply system. It is characterized in that all kinds of organic light emitting materials 3 are driven to emit light.

A white organic electroluminescent panel according to a second aspect of the present invention is a white organic electroluminescent panel formed by holding an organic luminescent material 3 between an anode 1 and a cathode 2. A plurality of types of organic light-emitting materials 3 having different emission colors are arranged in parallel, and one of the anode 1 and the cathode 2 is connected to an electrode connected to all types of the organic light-emitting materials 3 and the other is set to a plurality of types of organic light-emitting materials. The power supply system is formed from electrodes individually connected to the material 3, the individual power supply systems are connected to the electrodes individually connected to the organic light-emitting materials 3, and the power from each power supply system to the anode 1 and the cathode 2 is formed. It is characterized in that each organic light emitting material 3 is driven to emit light when supplied.

A white organic electroluminescent panel according to a third aspect of the present invention is a white organic electroluminescent panel formed by holding an organic luminescent material 3 between an anode 1 and a cathode 2. A plurality of types of organic light-emitting materials 3 having different emission colors are arranged in parallel, and both the anode 1 and the cathode 2 are formed from electrodes connected to all types of organic light-emitting materials 3. In this case, all kinds of organic light-emitting materials 3 are driven to emit light by supplying power to the anode 1 and the cathode 2 by the above-mentioned method.

According to a fourth aspect of the present invention, there is provided a method according to any one of the first to third aspects, wherein all kinds of the plurality of kinds of organic light emitting materials 3 having different emission colors are arranged in parallel between the anode 1 and the cathode 2. Are simultaneously emitted.

According to a fifth aspect of the present invention, in any one of the first to fourth aspects, two or more kinds of organic luminescent materials having different emission colors are used as the plurality of kinds of organic luminescent materials having different emission colors. It is characterized by becoming.

According to a sixth aspect of the present invention, in any one of the first to fourth aspects, as the plurality of kinds of organic light emitting materials 3 having different emission colors, three kinds of emission colors of blue, green and red are used. It is characterized by comprising.

A seventh aspect of the present invention is characterized in that, in any one of the first to sixth aspects, the light scattering sheet 4 is disposed on the light emitting surface side.

According to an eighth aspect of the present invention, in any one of the first to sixth aspects, the light emitting surface side is formed on the light scattering surface 5 having fine unevenness.

Conventionally, in a white light-emitting panel, an organic light-emitting material is formed by incorporating two or three types of dyes in one device under precise doping concentration control, and the organic light-emitting material emits white light. However, there are problems such as a decrease in reproducibility, a decrease in luminous efficiency, a decrease in life characteristics, and a color shift due to a difference in deterioration speed of each dye. In the present invention, as the light-emitting material, a plurality of different types of light-emitting colors, for example, blue,
Since three types of green and red and two types of independent organic light-emitting materials 3 having a complementary color relationship are used, the organic light-emitting materials 3 having high luminous efficiency and long life in each luminescent color are selected. This makes it possible to achieve higher efficiency and longer life than those containing a plurality of dyes. Further, in the present invention, it is only necessary to simply arrange a plurality of types of organic light-emitting materials 3 having different emission colors by, for example, separately applying them with a mask, thereby improving productivity.

[0018]

Embodiments of the present invention will be described below.

FIGS. 1 to 3 schematically show an embodiment of a white organic electroluminescent panel according to the present invention. An anode 1, a hole transport layer 11, an organic luminescent material 3 are provided on the surface of a substrate 10. FIG. , The electron transport layer 12 and the cathode 2. And anode 1
When a positive voltage is applied to the cathode 2 and a negative voltage is applied to the cathode 2, electrons injected into the organic light emitting material 3 via the electron transport layer 12 and holes injected into the organic light emitting material 3 via the hole transport layer 11 are generated. Are recombined in the organic light emitting material 3 to emit light.

The anode 1, which is an electrode for injecting holes into the organic light emitting material 3, can be formed of an electrode material having a large work function, such as a metal, an alloy, an electrically conductive compound, or a mixture thereof. It is preferable to use an electrode material having a work function of 4 eV or more. Specific examples of such an electrode material include metals such as gold,
TO (indium tin oxide), SnO ₂ , ZnO
And other conductive transparent materials. The anode 1 can be formed as a transparent electrode by forming a thin film of these electrode materials on the surface of the substrate 10 by a vacuum evaporation method, a sputtering method, or the like.

Here, a transparent substrate is used as the substrate 10,
When light emitted from the organic light emitting material 3 is transmitted through the anode 1 and irradiated from the substrate 10 to the outside, the light transmittance of the anode 1 is preferably set to 10% or more. Further, the sheet resistance of the anode 1 is preferably several hundred Ω / □ or less,
It is preferably at most 00Ω / □. Further, the thickness of the anode 1 varies depending on the material in order to control the characteristics of the anode 1 such as light transmittance and sheet resistance as described above.
00 nm or less, preferably in the range of 10 to 200 nm. Here, when a transparent conductive material is used for the anode 1, when the area of the light emitting portion is increased, the anode 1 of the transparent electrode is used.
May decrease the light emission uniformity due to the resistance loss of Al, Ti, and Ni having lower resistance.
A fine auxiliary electrode may be provided using a low-resistance metal such as.

When the light emitted from the organic light emitting material 3 is extracted from the substrate 10 side as described above, a transparent glass substrate is generally used as the substrate 10, but when flexibility and thinness are required, Alternatively, a film substrate having a high light transmittance can be used. When light emission of the organic light emitting material 3 is taken out from the side opposite to the substrate 10, light transmittance does not matter, so that in addition to a glass substrate, a metal substrate, a ceramic substrate, or the like is appropriately used from the viewpoint of heat dissipation. Can be.

On the other hand, for the cathode 2, which is an electrode for injecting electrons into the organic light emitting material 3, it is preferable to use an electrode material composed of a metal, an alloy, an electrically conductive compound and a mixture thereof having a small work function. It is preferable to use an electrode material having a work function of 5 eV or less. Such electrode material include sodium, sodium - potassium alloy, lithium, magnesium, aluminum, magnesium - silver mixture, a magnesium - indium mixture, an aluminum - lithium alloy, Al / Al ₂ O ₃ mixture, Al / Li
F mixture and the like. The cathode 2 can be produced, for example, by forming these electrode materials into a thin film by a method such as a vacuum evaporation method or a sputtering method. When light emitted from the organic light emitting material 3 is transmitted through the cathode 2 and irradiated to the outside, the cathode 2 preferably has a light transmittance of 10% or more. here,
The thickness of the cathode 2 varies depending on the material in order to control the characteristics such as the light transmittance of the cathode 2 as described above.
nm or less, and preferably in the range of 100 to 200 nm.

The hole transport material constituting the hole transport layer 11 has the ability to transport holes,
And a compound having an excellent hole injection effect on the organic light emitting material 3 while preventing electrons from moving to the hole transport layer 11 and having an excellent thin film forming ability. Can be. Specifically, phthalocyanine derivatives, naphthalocyanine derivatives, porphyrin derivatives, N, N'-bis (3-methylphenyl)-
(1,1′-biphenyl) -4,4′-diamine (TP
Aromatic diamine compounds such as D) and 4,4′-bis [N- (naphthyl) -N-phenyl-amino] biphenyl (α-NPD), oxazole, oxadiazole, triazole, imidazole, imidazolone, stilbene derivatives, Pyrazoline derivatives, tetrahydroimidazole, polyarylalkane, butadiene, 4,4 ′, 4 ″ -tris (N- (3-methylphenyl) N-phenylamino) triphenylamine (m-MTDATA), and polyvinylcarbazole, polysilane, Examples include, but are not limited to, polymeric materials such as conductive polymers such as polyethylene dioxide thiophene (PEDOT).

The electron transporting material constituting the electron transporting layer 12 has a capability of transporting electrons, has an effect of injecting electrons from the cathode 2, and has an excellent electron injecting effect on the organic light emitting material 3. And a compound that prevents holes from moving to the electron transport layer 12 and has an excellent ability to form a thin film. Specifically, fluorene, bathophenanthroline, bathocuproine, anthraquinodimethane, diphenoquinone, oxazole, oxadiazole, triazole, imidazole, anthraquinodimethane and the like and compounds thereof, a metal complex compound or a nitrogen-containing five-membered ring derivative. is there. Specifically, as the metal complex compound, tris (8-hydroxyquinolinate)
Aluminum, tri (2-methyl-8-hydroxyquinolinato) aluminum, tris (8-hydroxyquinolinato) gallium, bis (10-hydroxybenzo)
[h] quinolinato) beryllium, bis (10-hydroxybenzo [h] quinolinato) zinc, bis (2-methyl-8-quinolinato) (o-cresolate) gallium,
Bis (2-methyl-8-quinolinate) (1-naphtholate) aluminum and the like, but are not limited thereto. As the nitrogen-containing five-membered ring derivative, an oxazole, thiazole, oxadiazole, thiadiazole or triazole derivative is preferable. Specifically, 2,5-bis (1-phenyl) -1,3,4-oxazole, 2,5-bis (1-phenyl) -1,3,4
-Thiazole, 2,5-bis (1-phenyl) -1,
3,4-oxadiazole, 2- (4′-tert-butylphenyl) -5- (4 ″ -biphenyl) 1,3,4-oxadiazole, 2,5-bis (1-naphthyl)- 1,
3,4-oxadiazole, 1,4-bis [2- (5-
Phenylthiadiazolyl)] benzene, 2,5-bis (1-naphthyl) -1,3,4-triazole, 3-
(4-biphenylyl) -4-phenyl-5- (4-t
-Butylphenyl) -1,2,4-triazole and the like, but are not limited thereto. In recent years, there is also an electron transporting layer formed of a layer doped with a metal salt having a low work function to improve the effect of injecting electrons from the cathode 2. Further, a polymer material used for a polymer organic electroluminescence device can also be used. For example, polyparaphenylene and its derivatives, fluorene and its derivatives, and the like.

In the present invention, as the organic light emitting material 3 held between the anode 1 and the cathode 2, a plurality of kinds of materials having different emission colors are used, and the organic light emitting material 3 is conventionally used for an organic electroluminescence device. A light emitting material or a doping material can be used.

For example, blue light-emitting materials include benzoxazole zinc complex, oxadiazole zinc complex, azomethine zinc complex, phenylpyridine zinc complex, distyrylarylene zinc complex, cyclopentadiene, tetraphenylbutadiene, diphenylanthracene and its derivatives, perylene Derivatives, oligothiophene derivatives, BAlq having a mixed ligand of 2-methyl-8-quinolitol and a phenol derivative, and the like can be given. Examples of the blue dopant include DAS derivatives having carbazolyl groups at both ends, perylene, and the like. Of course, it is not limited to these.

As a green light emitting material, tris (8-
(Hydroxyquinolinato) aluminum complex (Alq
Many metal complex host materials such as zinc complex and beryllium complex having quinolinol ligand as well as 3) can be mentioned. In addition, examples of the dopant include coumarin 6, a quinacridone derivative, and the like. Recently, a high-efficiency material utilizing light emission from a triplet has been reported, and 4,4′-N, N′dicarbazolebiphenyl was used as a host and tris (2-phenylpyridine) iridium was used as a guest. Devices have also been proposed. Of course, it is not limited to these.

As a yellow light emitting material, Alq3 or T
One using PD as a host and using rubrene as a guest, and one in which the 8-quinolinol ligand of Alq3 is modified with a substituent to cause the host itself to emit yellow light (eg, Alph3, Alpd3, etc.) Can be used. Of course, it is not limited to these.

As the orange-red light emitting material, Alq3
Is used as a host, and a DCM derivative (for example, D
CM1, DCM2, DCJTB), a porphyrin derivative, a squarylium derivative, one using Nile Red, and one using an Eu complex (Eu (TTA) 3phen) as a host. Of course, it is not limited to these.

The light emitting material selected from the above compounds is 90 to 99.5% by mass, and the guest material is 0.5 to 1%.
The organic light emitting material 3 may be formed so as to contain 0% by mass. The thickness of the light emitting layer formed between the anode 1 and the cathode 2 by the organic light emitting material 3 is 0.5 to 500 n.
m is preferable, and 0.5 to 200 nm is more preferable.

In the present invention, the plurality of types of organic light-emitting materials 3 are arranged in parallel so as to constitute independent fine pixels.
In the embodiment shown in FIG. 1, for example, a blue light emitting organic light emitting material 3a, a green light emitting organic light emitting material 3b, and a red light emitting organic light emitting material 3c are arranged in parallel. In addition, at least one of the anode 1 and the cathode 2 is formed from an unpatterned solid electrode. In the embodiment of FIG. 1, the anode 1 is formed from a solid electrode. Organic light emitting materials 3a and 3 arranged in parallel in independent pixels
are provided on the solid anode 1. All the organic luminescent materials 3a, 3b... are electrically connected to one anode 1. In the embodiment shown in FIG. 1, the cathodes 2 are formed in an independent pattern corresponding to the organic light emitting materials 3a, 3b,.
a, 3b..., and the individual organic light emitting materials 3a, 3b
And each cathode 2 is individually connected.

FIG. 4A shows an organic light emitting material 3a emitting blue light and an organic light emitting material 3 emitting green light on a solid anode 1.
b, one of the embodiments in which the three color organic light emitting materials 3 of the red light emitting organic light emitting material 3c are arranged in parallel, and the blue light emitting organic light emitting material 3a and the green light emitting organic light emitting material 3a constituting each pixel are shown. Light emitting material 3b and red light emitting organic light emitting material 3c
Are repeatedly arranged in order.

In the embodiment of FIG. 1, the power supply 13 is wired so as to connect the anode 1 and the respective cathodes 2 to one power supply 13, and power is supplied by one power supply system using the power supply 13 in common. The embodiment of FIG. 1 shows an example of the white organic electroluminescent panel according to the first aspect of the present invention. In this device, a positive voltage is applied to the anode 1 and a negative voltage is applied to the cathode 2 by power supply from one power supply system, so that light emission driving of the organic light emitting materials 3a, 3b... Diffusion light from each of the blue, green, and red pixels is caused by simultaneously emitting the organic light emitting material 3a of the blue light emitting pixel, the organic light emitting material 3b of the green light emitting pixel, and the organic light emitting material 3c of the red light emitting pixel. And scattered light are mixed to obtain uniform light emission as a whole, and white light can be emitted as a whole by mixing light of three primary colors.

In this case, light can be emitted by controlling one power supply system for the entire panel, and the control mechanism can be simplified. In order to obtain white light, it is necessary to adjust the luminance of the pixels of each luminescent color. By adjusting the luminous area ratio of each white light, the luminance can be adjusted. Specifically, the luminous area for each white light is designed so that “luminance × total luminous area” of each luminous color in the entire panel is a luminance ratio for obtaining white light. Further, the light emitting portion is subdivided into fine pixels, and light is emitted from the organic material 3 constituting the pixel.
are only a, 3b,..., and a portion between pixels is a non-light emitting portion, and uniform light emission is obtained as a whole by diffused light and scattered light from the light emitting portion pixel. Therefore, the light emitting area of the entire device can be reduced, and low power consumption and high efficiency can be achieved.

Here, as a light-emitting panel in which organic light-emitting materials are arranged in pixels, a passive drive pixel display has been proposed. In this panel, it is necessary to control the on-off of light emission of each pixel independently. Therefore, it is necessary to perform fine patterning corresponding to pixels on both the anode and the cathode, and furthermore, it is necessary to perform complicated control necessary for performing the duty driving. On the other hand, since the white organic electroluminescent panel of the present invention is used for lighting purposes such as a backlight, each pixel of the organic light emitting material 3 can be used for full lighting driving or pulse driving on the entire panel, At least one of the anode 1 and the cathode 2 may be in a solid state without patterning. In addition, contrary to the above, the cathode is formed of unpatterned solid electrodes, and the anode is formed of patterned electrodes as a display.
An active drive TFT display in which light emission is turned on / off by an Si-TFT at an anode portion has been proposed. However, in the case of such a TFT display, it is necessary to perform brightness adjustment independently for each of the RGB pixels.
The control system becomes complicated as it becomes plural, and the Si-T
Those requiring a high-definition and high-cost process such as FT are not suitable for use in lighting applications. Further, it is not preferable for lighting applications from the viewpoint of lowering the aperture ratio by providing the TFT itself on the substrate.

In the embodiment shown in FIG. 2, an independent power source 13 is connected to each of the cathodes 2 which are individually connected to the plurality of types of organic light emitting materials 3a, 3b,.
A plurality of types of organic light emitting materials 3a, 3
b are individually supplied with power. The embodiment of FIG. 2 shows an example of the white organic electroluminescence panel according to the second aspect of the present invention. Other configurations are the same as those in FIG.

In this device, a positive voltage is applied to the anode 1 and a negative voltage is applied to the cathode 2 by power supply from each power supply system, so that the organic luminescent materials 3a, 3b of the entire panel are provided.
, The organic light emitting material 3a of a blue light emitting pixel, the organic light emitting material 3b of a green light emitting pixel, and the organic light emitting material 3c of a red light emitting pixel.
Simultaneously, the diffused light and scattered light from each pixel are mixed to obtain uniform light emission as a whole, and the white light is emitted as a whole by mixing the light of the three primary colors of blue, green and red. Can be done. In this case, the drive current value for driving the light emission of the organic light emitting material 3a of the blue light emitting pixel, the organic light emitting material 3b of the green light emitting pixel, and the organic light emitting material 3c of the red light emitting pixel can be individually set in each independent power supply system. It is possible to easily adjust the luminance ratio of each emission color necessary for obtaining white light emission. In addition, by individually controlling the drive current in each independent power supply system, the luminance ratio of each emitted color can be easily changed, and a white organic electroluminescent panel with variable color temperature and color tone can be used. It becomes something.

The embodiment shown in FIG. 3 shows an example of the white organic electroluminescent panel according to the third aspect of the present invention, in which both the anode 1 and the cathode 2 are formed from unpatterned solid electrodes. It is.
All the organic light emitting materials 3a, 3b... Arranged in parallel in independent pixels are provided on the solid anode 1, and the cathode 2 is passed over all the organic light emitting materials 3a, 3b. So that all organic light emitting materials 3
a, 3b,... are electrically connected to one anode 1 and one cathode 2. In this one one power supply 1
The power supply 3 is wired so as to connect the anode 1 and the cathode 2 so that power is supplied by one power supply system having a common power supply 13.

In this device, a positive voltage is applied to the anode 1 and a negative voltage is applied to the cathode 2 by power supply from one power supply system, so that the organic luminescent material 3a,
3b ... can be driven, and the blue and green organic light emitting materials 3a, the green light emitting pixel organic light emitting material 3b, and the red light emitting pixel organic light emitting material 3c emit light simultaneously to emit blue and green light. The diffused light and the scattered light from the red pixels are mixed to obtain uniform light emission as a whole and to emit white light as a whole by mixing the three primary colors. In this device, light can be emitted by controlling one power supply system for the entire panel, and the control mechanism can be simplified. Can be adjusted by the light emitting area ratio of the organic light emitting materials 3a, 3b... For each light emitting color.

In each of the above-described embodiments, three types of organic light emitting materials 3a, 3b,... Having different emission colors are used. Although a white panel having a three-wavelength content similar to that of a full-color LCD display is obtained, two or more types of organic light-emitting materials 3 having different emission colors may be used as two or more types of emission colors having a complementary color relationship. it can. A white organic electroluminescent panel can be formed in the same manner as in FIGS. 1 to 3 using the organic light emitting materials 3 of two kinds of emission colors having a complementary color relationship. By causing the entire organic light emitting material 3 to emit light simultaneously, each organic light emitting material 3
The diffused light and the scattered light from the light source are mixed to obtain uniform light emission as a whole and to emit white light as a whole by mixing light of two colors having a complementary color relationship.

As the two kinds of emission colors having a complementary color relationship, for example, a combination of blue and yellow or a combination of blue-green and orange can be used. In the case where the organic light emitting materials 3d and 3e of two kinds of emission colors having a complementary color relationship are used in this manner, for example, as shown in FIG. And one pixel between them is formed of the organic light emitting material 3e of the other emission color, and the number of pixels of the organic light emitting material 3d is arranged in parallel with the number of pixels of the organic light emitting material 3e. As shown in (c), the pixel of the organic light emitting material 3d of one emission color and the organic light emitting material 3e of the other emission color
Of pixels are alternately arranged in parallel.

FIG. 5 shows an embodiment of the invention according to claim 7, in which a light scattering sheet 4 is arranged on the light emitting surface side of a white organic electroluminescent panel. In the white organic electroluminescence panel of FIG. 5, the light-emitting surface is on the side of the substrate 10, so that the light-scattering sheet 4 is laminated on the substrate 10. The light diffusion sheet 4 is not particularly limited as long as it diffuses and transmits light, but preferably has a light diffusion transmittance of 50% or more. Specifically, a diffusion sheet used for a backlight for liquid crystal can be used. Other configurations are the same as those in FIGS.

FIG. 6 shows an example of the embodiment of the invention according to claim 8, wherein the light emitting surface of the white organic electroluminescent panel is formed on the light scattering surface 5 having fine unevenness. In the white organic electroluminescence panel of FIG. 6, since the outer surface of the substrate 10 is a light emitting surface, the outer surface of the substrate 10 is formed on the light scattering surface 5 with fine ground glass-like irregularities. Other configurations are the same as those in FIGS.

By providing the light scattering sheet 4 on the light emitting surface of the white organic electroluminescent panel or forming the light scattering surface 5 as described above, light emitted from the organic light emitting material 3 is efficiently extracted from the light emitting surface. It can enhance the luminous efficiency, enhance the color mixing of light of multiple luminescent colors, and obtain stable white light, and make the luminescence uniform to improve the light uniformity. It can be enhanced.

In each of the above embodiments, the size of one pixel of the organic light emitting material 3 is determined by the pattern shape of each pixel, the surface properties of the light emitting surface, the usage pattern as a lighting device (for example, the usage location, Although there is a variation due to factors such as the size of the light emitting portion, it is preferable that the size is fine. If the pixels of the organic light emitting material 3 are large, uniformity of light emission is reduced when a large number of pixel aggregates are formed into one light emitting surface. However, if the pixel is extremely small, an extremely fine pitch is required when patterning ITO or the like corresponding to the pixel, and the patterning process becomes technically difficult. The shape of the pixel of the organic light emitting material 3 is not limited to a normal square, but may be any shape such as a circle, an ellipse, a wedge, a stripe, or the like depending on required characteristics such as manufacturing stability, white light homogeneity, and luminous efficiency. You can choose. Further, the arrangement pattern of the pixels of the plurality of types of organic light emitting materials 3 is not particularly limited, but it is possible to stabilize the color mixture of light by increasing the degree of color mixing of light by reducing the ratio of the same type of color being present as close as possible. It is preferable for obtaining white color.

[0047]

Next, the present invention will be described specifically with reference to examples.

(Example 1) On a transparent glass substrate 10 having a thickness of 0.7 mm, ITO (indium-tin oxide) was sputtered to provide a solid anode 1 comprising a transparent electrode having a sheet resistance of 7Ω / □. The formed ITO glass substrate (manufactured by Sanyo Vacuum Corporation) was used. This ITO glass substrate was subjected to ultrasonic cleaning with acetone, pure water, and isopropyl alcohol for 15 minutes and then dried.

Next, this ITO glass substrate was set in a vacuum evaporation apparatus, and the following evaporations were performed.

First, 1.33 × 10 ⁻⁴ Pa (1 × 10 ⁻⁶ T)
orr) under reduced pressure of 4,4'-bis [N- (naphthyl)
-N-phenyl-amino] biphenyl (“α-NPD” manufactured by Dojindo Laboratories Inc.) was deposited at a deposition rate of 1-2 ° / s to a thickness of 400 °, and a hole transport layer 11 was formed on the anode 1.
Was formed. Next, on this hole transport layer 11, a DSA derivative having a carbazolyl group at a terminal represented by [Chemical Formula 2] (Distyrylbiphenyl derivative (“DPVBi” manufactured by Idemitsu Kosan Co., Ltd.)) (Idemitsu Kosan Co., Ltd.) Co., Ltd., “BCzVBi”) doped with 1% by mass is vapor-deposited in a total thickness of 500 °, and a blue-green light emitting organic light emitting material 3d
Was formed. Next, a tris (8-hydroxynolinato) aluminum complex (“Alq3” manufactured by Dojindo Laboratories, Inc.) was evaporated thereon at a deposition rate of 1-2 ° / s to a thickness of 200 ° to form an electron transport layer 12 thereon. LiF is first deposited thereon at a thickness of 5 ° at a deposition rate of 0.5 to 1.0 °, and then Al is deposited at a thickness of 15 ° at a deposition rate of 10 ° / s.
The cathode 2 was formed by vapor deposition at 00 °.

[0051]

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[0052]

Embedded image

After the hole transport layer 11 is formed on the anode 1 in the same manner, the above-mentioned “Alq3” doped with 1% by mass of “DCM2” manufactured by Nippon Kosaku Dyeing Co., Ltd. is vapor-deposited at a total thickness of 500 °. Orange light emitting organic light emitting material 3e
(Also serving as an electron transport layer). Next, a cathode 2 was formed thereon in the same manner as described above.

As described above, as shown in FIG. 4B, pixels made of the organic light emitting material 3d emitting blue-green light and pixels made of the organic light emitting material 3e emitting orange light are arranged in parallel in a stripe form. A blue-green + orange-type white light-emitting electroluminescent panel having a cross-sectional structure as shown in FIG. The size of each pixel in the stripe shape was formed to be 0.5 mm in width, and the interval was set to 0.5 mm. The driving is 10 mA current density for each pixel.
/ Cm ² was supplied under the condition of supplying a current.

(Example 2) The same ITO glass substrate as in Example 1 was set in a vacuum evaporation apparatus, and the following respective evaporations were performed.

First, a hole transport layer 11 was formed on the anode 1 in the same manner as in Example 1. Next, this hole transport layer 1
1 and the above “BCzVBi” to the above “DPVBi”
Was doped by 1% by mass to form a blue light emitting organic light emitting material 3a by vapor deposition at a total thickness of 500 °. Next, the electron transport layer 12 was formed thereon in the same manner as in Example 1, and the cathode 2 was formed thereon in the same manner as in Example 1.

After forming the hole transport layer 11 on the anode 1 in the same manner, the above-mentioned “Alq3” obtained by doping 1% by mass of “Coumarin-6” manufactured by ACROSS Co., Ltd. was evaporated to a total thickness of 500 ° to emit green light. The organic light emitting material 3b (also serving as an electron transport layer) was formed. Next, a cathode 2 was formed thereon in the same manner as in Example 1.

After the hole transport layer 11 was similarly formed on the anode 1, the above-mentioned “Alq3” doped with 1% by mass of “DCJTB” manufactured by Kodak Co. was vapor-deposited to a total thickness of 500 ° to form a red light-emitting organic layer. A light-emitting material 3c (also serving as an electron transport layer) was formed. Next, the embodiment 1
A cathode 2 was formed in the same manner as described above.

As described above, as shown in FIG. 4A, the pixel made of the organic light emitting material 3a emitting blue light, the pixel made of the organic light emitting material 3b emitting green light, and the pixel made of the organic light emitting material 3c emitting red light are used. A blue + green + red type white light-emitting electroluminescent panel which was provided in parallel in a stripe shape and formed in a sectional structure as shown in FIG. 1 was obtained. The size of each pixel in the stripe shape was formed to be 0.5 mm in width, and the interval was set to 0.5 mm. The driving is 10 mA current density for each pixel.
/ Cm ² was supplied under the condition of supplying a current.

(Example 3) Organic light-emitting material 3 emitting blue-green light
FIG. 4C is a cross-sectional view similar to that of the first embodiment, except that the pixel in FIG. 4D and the stripe-shaped parallel arrangement of the pixel in the orange light-emitting organic light-emitting material 3e are set as shown in FIG. A blue-green + orange-type white light-emitting electroluminescence panel formed in a structure was obtained. The drive sets the current supply to the pixel of the blue-green light emitting organic light emitting material 3d to a current density of 10 mA / cm ² and the current supply to the pixel of the orange light emitting organic light emitting material 3e to a current density of 15 mA / cm ² . Performed under the conditions set.

Example 4 A light diffusion sheet 4 (“Opulse # 100-KBS2” manufactured by Ewa Corporation: 130 μm in thickness) was formed on the outer surface of the substrate 10 of the light emitting panel obtained in Example 1.
Was applied to obtain a white light-emitting electroluminescent panel formed in a cross-sectional structure as shown in FIG. The driving is 10 mA current density for each pixel.
/ Cm ² was supplied under the condition of supplying a current.

(Example 5) In Example 1, a glass substrate 10 was used in which the outer surface was finely polished with a sand blaster for 1 minute and ground glass processing was performed to form a light scattering surface 5, and the other examples were used. In the same manner as in Example 1, a white light-emitting electroluminescent panel formed in a sectional structure as shown in FIG. 6 was obtained. Driving was performed under the condition of supplying a current of 10 mA / cm ² to each pixel.

(Comparative Example 1) The same ITO glass substrate as in Example 1 was set in a vacuum evaporation apparatus, and each of the following evaporations was performed.

First, a hole transport layer 11 was formed on the anode 1 in the same manner as in Example 1. Next, this hole transport layer 1
The above “DCM2” is added to the above “α-NPD” by 1
An organic light-emitting material 3e that emits orange light was formed by vapor-depositing the material doped with mass% to a thickness of 100 °. Further, the above-mentioned "DPVBi" doped with 1% by mass of "BCzVBi" was vapor-deposited at a total thickness of 500 [deg.] To form a blue-green light emitting organic light emitting material 3d. Next, the embodiment 1
The electron transport layer 12 was formed in the same manner as described above, and the cathode 2 was formed thereon in the same manner as in Example 1.

As described above, as shown in FIG. 7, a blue-green + orange-type white light is formed in a cross-sectional structure in which a blue-green light-emitting organic light-emitting material 3d and an orange light-emitting organic light-emitting material 3e are provided one above the other. A light emitting electroluminescent panel was obtained.
The driving was performed under the condition of supplying a current having a current density of 10 mA / cm ² .

(Comparative Example 2) The same ITO glass substrate as in Example 1 was set in a vacuum evaporation apparatus, and the following respective evaporations were performed.

First, a hole transport layer 11 was formed on the anode 1 in the same manner as in Example 1. Next, this hole transport layer 1
The above “DCM2” is added to the above “α-NPD” by 3
An organic light emitting material 3c for emitting red light was formed by depositing the material doped with mass% to a thickness of 100 °. Next, the above “A
1q3 "doped with 1% by mass of the above" coumarin-6 "was vapor-deposited at a total thickness of 500 [deg.] to form a green light emitting organic light emitting material 3b. Furthermore, the above-mentioned "DPVB
i) was doped with the above-mentioned "BCzVBi" by 1% by mass, and was vapor-deposited at a total thickness of 200 [deg.] to form an organic light emitting material 3a emitting blue light. Next, the electron transport layer 12 was formed thereon in the same manner as in Example 1, and the cathode 2 was formed thereon in the same manner as in Example 1.

As described above, as shown in FIG. 8, a blue light emitting organic light emitting material 3a, a green light emitting organic light emitting material 3b, and a red light emitting organic light emitting material 3c were formed in a cross-sectional structure provided one above the other. A blue-green-red-type white light-emitting electroluminescent panel was obtained. And drive is current density 1
The test was performed under the condition of supplying a current of 0 mA / cm ² .

The white light-emitting electroluminescent panels produced in Examples 1 to 4 and Comparative Examples 1 and 2 were connected to a power supply (KEYTHLEY 236 model) to emit light, and the luminance was measured with a luminance meter (“LS-110” manufactured by Minolta Co.). ), And the luminous efficiency and CIE chromaticity were measured by “Multi-Channel Analyzer PMA-10” manufactured by Hamamatsu Photonics. The luminance is 50, which is half of the initial value of 100 cd / m ^2.
The half-life, which is the time required to reach cd / m ² , was measured. Table 1 shows the results.

[0070]

[Table 1]

[0071]

As described above, the white organic electroluminescent panel according to claim 1 of the present invention is a white organic electroluminescent panel formed by holding an organic light emitting material between an anode and a cathode. A plurality of types of organic light emitting materials having different emission colors are arranged in parallel between,
At least one of the anode and the cathode is formed from electrodes connected to all kinds of organic light-emitting materials, and light emission driving of all kinds of organic light-emitting materials is performed by supplying power to the anode and the cathode by one power supply system. Is performed, light of different colors emitted from a plurality of kinds of light emitting materials can be mixed to emit white light. As a light emitting material, high luminous efficiency and long life which have been conventionally used can be obtained. It is possible to select and use the selected one, and it is possible to achieve high luminous efficiency and long life. In addition, since at least one of the anode and the cathode is formed from electrodes connected to all kinds of organic light emitting materials, the electrodes can be left solid, and patterning is not required, thereby improving productivity. Is what you do.

A white organic electroluminescent panel according to a second aspect of the present invention is a white organic electroluminescent panel formed by holding an organic light emitting material between an anode and a cathode. A plurality of different types of organic light-emitting materials are arranged in parallel, and one of an anode and a cathode is connected to all types of organic light-emitting materials, and the other is individually connected to a plurality of types of organic light-emitting materials. Each power supply system is connected to an electrode individually connected to each organic light-emitting material, and each organic light-emitting material is driven to emit light by supplying power to the anode and the cathode from each power supply system. As a result, light of different colors emitted from a plurality of types of light emitting materials can be mixed to emit white light. It is one that can be used to select what life is obtained, in which high luminous efficiency and long life becomes possible. In addition, since one of the anode and the cathode is formed from an electrode connected to all kinds of organic light emitting materials, the electrode may be left solid, and patterning is not required, thereby improving productivity. Things. Further, each power supply system is connected to an electrode individually connected to each organic light-emitting material, and light emission driving of each organic light-emitting material is performed by supplying power to the anode and the cathode from each power supply system. Therefore, the drive current value for driving each organic light emitting material to emit light can be individually set, and the adjustment of the luminance ratio of each emission color required to obtain white light emission can be easily performed. By individually controlling the drive current in each independent power supply system, the luminance ratio of each emission color can be easily changed, and the color temperature and color tone can be made variable.

A white organic electroluminescent panel according to a third aspect of the present invention is a white organic electroluminescent panel formed by holding an organic light emitting material between an anode and a cathode. Different types of organic light-emitting materials are arranged in parallel, both the anode and the cathode are formed from electrodes connected to all types of organic light-emitting materials, and power is supplied to the cathode and the anode by one power supply system Since all types of organic light emitting materials are driven to emit light, white light can be mixed by mixing different colors of light emitted from a plurality of types of light emitting materials. It is possible to select and use a material having high luminous efficiency and long life as described above, and it is possible to achieve high luminous efficiency and long life. In addition, since both the anode and the cathode are formed from electrodes connected to all types of organic light emitting materials, the electrodes may be left solid, and patterning is not required, thereby improving productivity. Things.

According to a fourth aspect of the present invention, a plurality of types of organic luminescent materials having different luminescent colors arranged in parallel between an anode and a cathode are made to emit light at the same time. Can emit white light by mixing different colors of light emitted from the device.

According to the fifth aspect of the present invention, two types of organic light emitting materials having complementary colors are used as a plurality of types of organic light emitting materials having different emission colors. By mixing light having a complementary color relationship, stable white light can be emitted.

Further, according to the invention of claim 6, three kinds of organic luminescent materials of blue, green and red are used as a plurality of kinds of organic luminescent materials having different luminescent colors. The three primary colors can be mixed to emit stable white light.

According to the seventh aspect of the present invention, since the light-scattering sheet is disposed on the light-emitting surface side, light emitted from the organic light-emitting material can be efficiently extracted by light scattering by the light-scattering sheet, and the luminous efficiency can be increased. In addition, a stable white light can be obtained by enhancing the color mixing of light of a plurality of kinds of emission colors.

According to the invention of claim 8, since the light emitting surface side is formed as a light scattering surface having fine irregularities, light emitted from the organic light emitting material can be efficiently extracted by light scattering by the light scattering surface. Efficiency can be increased, and stable white light can be obtained by enhancing the color mixing of light of a plurality of kinds of emission colors.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an example of an embodiment of the present invention.

FIG. 2 is a schematic sectional view showing another example of the embodiment of the present invention.

FIG. 3 is a schematic sectional view showing another example of the embodiment of the present invention.

FIG. 4 is a view showing an arrangement of the organic light emitting material according to the first embodiment;
(A), (b), (c) are schematic diagrams, respectively.

FIG. 5 is a schematic sectional view showing another example of the embodiment of the present invention.

FIG. 6 is a schematic sectional view showing another example of the embodiment of the present invention.

FIG. 7 is a schematic sectional view of Comparative Example 1.

FIG. 8 is a schematic sectional view of Comparative Example 2.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Anode 2 Cathode 3 Organic light emitting material 4 Light scattering sheet 5 Light scattering surface

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Junji Kido 9-4-3, Mamikita, Koryo-cho, Kitakatsuragi-gun, Nara Pref. 72) Inventor Kenji Tsubaki 1048 Kazuma Kadoma, Kadoma City, Osaka Prefecture F-term in Matsushita Electric Works, Ltd. (reference) 3K007 AB03 AB04 AB11 AB18 CA01 CB01 DA01 DB03 EB00

Claims (8)

[Claims] 1. A white organic electroluminescent panel formed by holding an organic light emitting material between an anode and a cathode, wherein a plurality of types of organic light emitting materials having different emission colors are arranged in parallel between the anode and the cathode. And at least one of the cathodes is formed from electrodes connected to all kinds of organic light emitting materials, and the light emission drive of all kinds of organic light emitting materials is performed by supplying power to the anode and the cathode by one power supply system. A white organic electroluminescent panel, characterized in that the white organic electroluminescent panel is formed. 2. A white organic electroluminescence panel formed by holding an organic light emitting material between an anode and a cathode, wherein a plurality of types of organic light emitting materials having different emission colors are arranged in parallel between the anode and the cathode. And one of the cathodes is formed from electrodes connected to all types of organic light-emitting materials, and the other is formed from electrodes individually connected to a plurality of types of organic light-emitting materials, and individually connected to each organic light-emitting material. A white organic electroluminescent panel, wherein each of the power supply systems is connected to a corresponding one of the electrodes, and the organic light-emitting material is driven to emit light by supplying power to the anode and the cathode from each of the power supply systems. 3. A white organic electroluminescent panel formed by holding an organic light emitting material between an anode and a cathode, wherein a plurality of types of organic light emitting materials having different emission colors are arranged in parallel between the anode and the cathode. And the cathode are formed from electrodes connected to all kinds of organic light emitting materials, and the light emission driving of all kinds of organic light emitting materials is performed by supplying power to the cathode and the anode by one power supply system. A white organic electroluminescent panel characterized in that: 4. The method according to claim 1, wherein all of a plurality of kinds of organic light-emitting materials having different emission colors arranged in parallel between the anode and the cathode emit light simultaneously. The white organic electroluminescent panel according to the above. 5. The white color according to claim 1, wherein two or more kinds of organic light emitting materials having different emission colors are used, which are two kinds of emission colors having a complementary color relationship. Organic electroluminescence panel. 6. The method according to claim 1, wherein the plurality of types of organic light-emitting materials having different emission colors include three kinds of emission colors of blue, green, and red. White organic electroluminescence panel. 7. The white organic electroluminescent panel according to claim 1, wherein a light scattering sheet is disposed on the light emitting surface side. 8. The white organic electroluminescent panel according to claim 1, wherein the light emitting surface is formed on a light scattering surface having fine irregularities.