JPH11191491A - Organic electroluminescent device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organic electroluminescent device superior in display characteristic. SOLUTION: An organic electroluminescent device contains a first electrode 2 formed on a substrate 1, a thin-film layer containing at least a luminescent layer 6 comprising an. organic compound and formed on the first electrode 2, and plural second electrodes 8 formed on the thin-film layer. Plural luminescent regions are formed on the substrate 1 in the organic electroluminescent device. A spacer 4 having at least one part thereof which has height exceeding the thickness of the thin-film layer is formed on the substrate 1, and at least one part of the spacer 4 is black.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic electroluminescent device having a plurality of light emitting areas formed by organic electroluminescent elements on the same substrate, which can be used in fields such as display devices, flat panel displays, backlights and interiors. About.

[0002]

2. Description of the Related Art In recent years, an organic electroluminescent device has attracted attention as a new light emitting device. This element emits light by the recombination of the holes injected from the anode and the electrons injected from the cathode in the organic light emitting layer sandwiched between both electrodes,
It is possible to emit light with high luminance at a low voltage by C.D. W.
Tang et al. (Appl. Phy.
s. Lett. 51 (12) 21, p. 913,198
7).

FIG. 28 is a sectional view showing a typical structure of an organic electroluminescent device. On a transparent first electrode (anode) 2 formed on a glass substrate 1, a hole transport layer 5, an organic light emitting layer 6,
The second electrode (cathode) 8 is stacked, and light emitted by driving by the driving source 9 is extracted to the outside through the first electrode and the glass substrate. Such an organic electroluminescent device is thin,
High luminance light emission under low voltage driving and multi-color light emission by selecting an organic light emitting material are possible, and application to light emitting devices such as display elements and displays has been actively studied.

One example of a conventional light emitting device using an organic electroluminescent element is shown in FIGS. This light-emitting device is a simple matrix type color display, and can display an image and the like in color by being driven in a line-sequential manner. In the above color display, it is necessary to pattern at least the organic light emitting layer and the second electrode, and in the case of a monochrome display, at least the second electrode.

As a method for patterning the second electrode, Japanese Patent Application Laid-Open No. 5-275172 and Japanese Patent Application Laid-Open No. 8-315981 are known.
The technique disclosed in Japanese Patent Laid-Open No. H10-209,837 is disclosed. JP-A-5-27517
The technique disclosed in Japanese Patent Application Laid-open No. 2 (1995) -27911 forms barrier ribs arranged at intervals on a substrate, and deposits an electrode material on the substrate in an oblique direction. The light emitting device having the structure shown in FIGS. Can be manufactured. Also, Japanese Patent Application Laid-Open No. 8-315
No. 981 discloses a technique in which a partition having an overhang portion is formed on a substrate, and an electrode material is deposited on the substrate in an angle range centered on a vertical direction. In each of the techniques, the second electrode is patterned by using a shadow of a deposit created by a partition (spacer) having a height exceeding the thickness of the thin film layer.

[0006]

However, in the above-mentioned prior art, the spacer having a height exceeding the thickness of the thin film layer is formed of an acrylic or polyimide transparent resin material. Since the spacer is disposed between the second electrodes, that is, in the non-light-emitting region as shown in FIG. 32, light emission from the light-emitting region, reflection, scattering, transmission, and the like of light from the light-emitting region occur in the transparent portion. There is a problem that the display characteristics of the electroluminescent device are deteriorated.

It is an object of the present invention to solve such a problem and to provide an organic electroluminescent device having excellent display characteristics.

[0008]

According to the present invention, there is provided an organic electroluminescent device comprising: a first electrode formed on a substrate; and a thin film layer including at least a light emitting layer made of an organic compound and formed on the first electrode. A plurality of second electrodes formed on the thin film layer, the organic electroluminescent device having a plurality of light emitting regions on the substrate, at least a portion of the height of the thin film layer exceeds the thickness The spacer is formed on the substrate, and at least a part of the spacer is black.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An organic electroluminescent device according to the present invention is provided with a plurality of light emitting regions by an organic electroluminescent element on the same substrate. The present invention will be described below,
The present invention is not limited to the organic electroluminescent device having the exemplified form and structure, but is not limited to segment type, simple matrix type, active matrix type, etc.
The present invention can be applied to an organic electroluminescent device having an arbitrary structure regardless of the number of emission colors such as monochrome.

[0010] In the organic electroluminescent device of the present invention, a spacer having at least a portion having a height exceeding the thickness of the thin film layer is formed on the substrate, and at least a portion of the spacer is black. It is characterized by.
One example is shown in FIGS. A thin-film layer 10 including a stripe-shaped first electrode 2 formed on a substrate 1 and a light-emitting layer 6 made of an organic compound patterned on each first electrode
And a second electrode 8 in the form of a stripe orthogonal to the first electrode. A plurality of light emitting regions having an organic electroluminescent element structure are formed at intersections of the two electrodes. Each light-emitting region emits red (R), green (G), and blue (B) light by using different materials for the light-emitting layer. By driving this simple matrix light-emitting device line-sequentially, an image or the like is displayed in color. It is possible to Further, a black spacer 4 having a height exceeding the thickness of the thin film layer is formed between the second electrodes, and a part of the non-light emitting region becomes black as shown in FIG. Therefore, it is possible to further reduce the reflection, scattering, transmission, and the like of light emission from the light emitting region and external light, and it is possible to sharpen the boundary of the light emitting region. Display characteristics such as contrast are improved. Hereinafter, the organic electroluminescent device of the present invention will be described in detail using this structure as an example.

The structure of the spacer is not particularly limited. The spacer may be formed by a single layer, a plurality of layers may be laminated, or a plurality of layers having a planar shape such as a circle or a polygon. Can be arranged on the substrate. For example, in the organic electroluminescent device shown in FIGS. 1 to 3, the spacer 4 may be a single black layer, or may have a laminated structure including one or more black layers. In the case of a laminated structure, the spacer substrate 1
Alternatively, a portion in contact with the first electrode 2 may be black, or a portion of the spacer in contact with the substrate or the first electrode may be a transparent layer, and a black layer may be formed thereon.

In the spacer having a laminated structure, it is not necessary that each layer has the same planar shape. For example, FIGS.
As shown in FIG. 2, a first spacer 3 having a relatively small thickness is provided between the first electrodes 2 and a second spacer 4 having a height exceeding the thickness of the thin film layer is perpendicularly provided between the first electrodes 2. 8, and at least one of both spacers can be made black. As shown in FIGS. 8 to 10, a matrix-like first spacer added between the second electrodes 8 and having an additional function as an interlayer insulating layer covering the end of the first electrode 2. 3 may be formed on the substrate 1 and laminated thereon to form the second spacer 4 located between the second electrodes.

The cross-sectional shape of the spacer is not particularly limited.
It may be a taper type or a reverse taper type. As for the height of the spacer, at least a part thereof may have a height exceeding the thickness of the thin film layer, and is not particularly limited, but is usually formed in the range of 0.1 to 100 μm.

Although the position where the spacer is arranged is not particularly limited, it is preferable to arrange the spacer around the non-light emitting region in the organic electroluminescent device so as to minimize the area loss of the light emitting region. Furthermore, FIG.
In the light emitting device shown in FIG. 7, if the first spacer 3 and the second spacer 4 are used, and in the light emitting device shown in FIGS. 8 to 10, at least the first spacer 3 is made black, as shown in FIG. The non-light emitting region becomes black, and the display characteristics can be further improved. Thus, it can be said that the arrangement in which the light emitting region is surrounded by the spacer at least partially black is particularly preferable.

Since the spacer is often formed in contact with the first electrode, it is preferable that at least a portion of the spacer that contacts the substrate or the first electrode has electrical insulation. However, it is also possible to positively form an electrically conductive portion on the spacer. In this case, an electrically insulating portion for preventing a short circuit between the first electrodes may be formed together. For example, as shown in FIGS. 12 to 14, a spacer 4 having a height exceeding the thickness of the thin film layer 10 is arranged between the second electrodes. An electrically conductive portion 15 extending in the direction of the second electrode 8 is provided on one side surface of the spacer.
Are formed, and the electrically conductive portion and the first electrode 2 are formed.
Since there is an electrically insulating portion constituting the spacer between them, the first electrodes are not electrically short-circuited.
With this configuration, the electric conductive portion functions as a guide electrode, and the electric resistance of the second electrode can be reduced. Therefore, a voltage drop during line-sequential driving is reduced, and an effect of reducing uneven brightness and power consumption in the light emitting device can be expected.

Known materials can be used as the insulating spacer material. For inorganic materials, oxide materials such as silicon oxide, glass materials, ceramic materials, and the like, and for organic materials, polyvinyl, polyimide, and polystyrene are used. Preferred examples include polymer-based resin materials such as a resin, an acrylic, a novolak, and a silicone. Further, as a spacer material for the black portion, an inorganic material such as silicon, gallium arsenide, manganese dioxide, titanium oxide or a laminated film of chromium oxide and metal chromium is used. Known pigments and dyes such as treated carbon black, phthalocyanine, anthraquinone, monoazo, disazo, metal complex salt type monoazo, triallylmethane, aniline, etc., or mixed with the above inorganic material powder Materials can be mentioned as preferred examples. Further, a spacer having low reflection characteristics may be formed by utilizing a known optical interference filter technique.

Further, as the material of the electrically conductive portion, various materials which have already been exemplified as the first and second electrode materials can be mentioned as preferable examples.

In the above description, "black" does not limit the hue, but means that it has a relatively wide light absorption region or low light reflection region in the visible light region.
Therefore, it may be a dark color such as brown, navy blue, or purple. The optical absorption or reflection characteristics of the spacer may be optimized as needed, and are not particularly limited.

The method for manufacturing the organic electroluminescent device of the present invention is not limited. Therefore, the organic electroluminescent device of the present invention can be manufactured by using a known technique such as the above-mentioned partition method.

The first and second electrodes only need to have a conductivity capable of supplying a current sufficient for light emission of the organic electroluminescent device.
Preferably, at least one of the electrodes is transparent to extract light.

A transparent electrode has no major obstacle to its use if the visible light transmittance is 30% or more, but ideally 100%.
Is preferably closer to Basically, it is preferable to have the same transmittance in the entire visible light range. However, when it is desired to change the emission color, it is possible to positively impart light absorbency. In such a case, it is technically easy to change the color using a color filter or an interference filter. Transparent electrode materials include indium, tin, gold,
It is often composed of at least one element selected from silver, zinc, aluminum, chromium, nickel, oxygen, nitrogen, hydrogen, argon, carbon, but inorganic conductive substances such as copper iodide and copper sulfide, polythiophene, polypyrrole It is also possible to use a conductive polymer such as polyaniline or the like, and there is no particular limitation.

Preferred examples of the first electrode material include tin oxide, zinc oxide, indium oxide, vanadium oxide, and indium tin oxide (ITO) formed on a transparent substrate. In display applications where patterning is performed, it is particularly preferable to use ITO having excellent workability for the first electrode. ITO may contain a small amount of metal such as silver or gold to improve conductivity, and use tin, gold, silver, zinc, indium, aluminum, chromium, and nickel as ITO guide electrodes. It is also possible. In particular, chromium is a preferred guide electrode material because it can have both functions of a black matrix and a guide electrode. From the viewpoint of power consumption of the organic electroluminescent device, the resistance of ITO is preferably low. An ITO substrate having a resistance of 300 Ω / □ or less functions as the first electrode. However, it is now easy to supply an ITO substrate having a resistance of about 10 Ω / □, so that a low resistance product can be used. The thickness of the ITO can be arbitrarily selected according to the resistance value, but usually the thickness is 100 to 300 nm.
Is often used. The material of the transparent substrate is not particularly limited, and a plastic plate or film made of polyacrylate, polycarbonate, polyester, polyimide, or aramid can be used. A preferred example is a glass plate. As for the material of the glass, soda lime glass or the like provided with a barrier coat such as non-alkali glass or silicon oxide film can be used. In addition, the thickness is 0.5 mm because it is sufficient to maintain the mechanical strength.
That's enough. The method for forming ITO is not particularly limited, such as electron beam evaporation, sputtering evaporation, and a chemical reaction method.

The material of the second electrode is not particularly limited. However, when ITO is used as the first electrode, since the ITO generally functions as an anode, electrons are efficiently applied to the organic electroluminescent device by the second electrode. It is required to function as a cathode that can be injected well. Therefore, it is possible to use a low work function metal such as an alkali metal as the second electrode material, but considering the stability of the electrode, platinum, gold, silver,
It is preferable to use metals such as copper, iron, tin, aluminum, magnesium and indium, or alloys of these metals with low work function metals. In addition, a small amount of a low work function metal is doped in the thin film layer of the organic electroluminescent element in advance, or a thin metal salt layer such as lithium fluoride is formed on the thin film layer. By forming the electrodes as two electrodes, a stable electrode can be obtained while maintaining high electron injection efficiency. The method for forming the second electrode is not particularly limited as long as it is a dry process such as resistance heating evaporation, electron beam evaporation, sputtering evaporation, or ion plating.

The thin film layers included in the organic electroluminescent device include 1) a hole transport layer / light emitting layer, 2) a hole transport layer / light emitting layer / electron transport layer, 3) a light emitting layer / electron transport layer, and 4)
Any of the above-mentioned light emitting layers in which the layer constituting materials are mixed in one layer may be used. That is, if a light emitting layer made of an organic compound exists as a device configuration, the above-mentioned 1) to 3)
In addition to the multi-layer structure, the light emitting material alone or a single light emitting layer containing the light emitting material and the hole transporting material or the electron transporting material as in 4) may be provided.

The hole transporting layer is formed of a hole transporting material alone or a hole transporting material and a polymer binder. As a hole transport material, N, N′-diphenyl-N, N′-di (3-methylphenyl) -1,1 ′ is used for a low molecular weight compound.
-Diphenyl-4,4'-diamine (TPD), N,
N'-diphenyl-N, N'-dinaphthyl-1,1'-
Heterocycles such as triphenylamines represented by diphenyl-4,4'-diamine (NPD), N-isopropylcarbazole, pyrazoline derivatives, stilbene compounds, hydrazone compounds, oxadiazole derivatives and phthalocyanine derivatives Compounds and the like, and, in a polymer system, a polycarbonate or a styrene derivative having the low-molecular compound in a side chain, polyvinyl carbazole,
Preferred examples include polysilane.

In the application of the simple matrix type light emitting device, the light emitting time of each organic electroluminescent element is short, and it is necessary to instantaneously emit light with high luminance by passing a pulse current. In such a case, the hole transporting material is required to have not only excellent hole transporting properties and stable thin film forming ability, but also good electron blocking properties to prevent a decrease in luminous efficiency due to leakage of electrons in the hole transporting layer. Is done. In order to satisfy the above characteristics in a well-balanced manner, in the present invention, it is particularly preferable to form an organic layer comprising an organic compound having a biscarbazolyl skeleton shown below.

[0027]

Embedded image Here, R1 and R2 are selected from hydrogen, alkyl, halogen, aryl, aralkyl and cycloalkyl. The carbazolyl skeleton may have one or more substituents selected from alkyl, aryl, aralkyl, carbazolyl, substituted carbazolyl, halogen, alkoxy, dialkylamino, and trialkylsilyl groups.

Examples of the light emitting material include anthracene derivatives, pyrene derivatives, 8-hydroxyquinoline aluminum derivatives, bisstyrylanthracene derivatives, tetraphenylbutadiene derivatives, coumarin derivatives, and oxadiazoles, which have been known as light emitters in the case of low molecular weight compounds. Derivatives, distyrylbenzene derivatives, pyrrolopyridine derivatives, perinone derivatives, cyclopentadiene derivatives, oxadiazole derivatives, thiadiazolopyridine derivatives, etc., in the case of polymer systems, polyphenylenevinylene derivatives,
Preferred examples include polyparaphenylene derivatives and polythiophene derivatives. Preferred examples of the dopant for doping the light-emitting layer include rubrene, quinacridone derivatives, phenoxazone derivatives, DCM, perinone derivatives, perylene derivatives, coumarin derivatives, and diazaindacene derivatives.

Since the electron transporting material is required to efficiently transport the electrons injected from the cathode, it is preferable that the electron transporting material has a large electron affinity, a large electron mobility, and a stable thin film forming ability. As materials satisfying such characteristics, 8-hydroxyquinoline aluminum derivatives, hydroxybenzoquinoline beryllium derivatives, 2- (4-
Biphenyl) -5- (4-t-butylphenyl) -1,
3,4-oxadiazole (t-BuPBD), 1,3
-Bis (4-t-butylphenyl-1,3,4-oxadizolyl) biphenylene (OXD-1), 1,3-bis (4-t-butylphenyl-1,3,4-oxadizolyl) phenylene (OXD- Oxadiazole derivatives, triazole derivatives, phenanthroline derivatives and the like such as 7) can be mentioned as preferred examples.

The materials used for the above-described hole transporting layer, light emitting layer and electron transporting layer can be used alone to form each layer. As the polymer binder, polyvinyl chloride, polycarbonate, polystyrene, poly (N- Vinyl carbazole), polymethyl methacrylate, polybutyl methacrylate, polyester, polysulfone, polyphenylene oxide, polybutadiene, hydrocarbon resin, ketone resin, phenoxy resin, polysulfone, polyamide,
Solvent-soluble resins such as ethyl cellulose, vinyl acetate, ABS resin, polyurethane resin, phenolic resin, xylene resin, petroleum resin, urea resin, melamine resin, unsaturated polyester resin, alkyd resin, epoxy resin,
It can be used by being dispersed in a curable resin such as a silicone resin.

The method for forming the hole transport layer, the light emitting layer, the electron transport layer, and the like is not particularly limited, such as resistance heating evaporation, electron beam evaporation, and sputtering evaporation. Is preferred in terms of characteristics. The thickness of the organic layer cannot be limited because it is related to the resistance value, but is empirically selected from the range of 10 to 1000 nm.

It is also possible to use an inorganic material for the whole or a part of the hole transport layer or the electron transport layer. Preferred examples include silicon carbide, gallium nitride, zinc selenide, and zinc sulfide-based inorganic semiconductor materials.

[0033]

The present invention will be described below with reference to examples and comparative examples, but the present invention is not limited to these examples.

Example 1 A shadow mask having a structure in which a mask portion and a reinforcing line were formed on the same plane as shown in FIG. 15 was prepared for patterning a light emitting layer. The outline of the shadow mask is 12
0 × 84 mm, the thickness of the mask portion 31 is 25 μm, and 92 stripe-shaped openings 32 having a length of 64 mm and a width of 300 μm are arranged in a horizontal direction at a pitch of 900 μm. Each stripe-shaped opening has a width 2 orthogonal to the opening.
Reinforcing wires 33 having a thickness of 0 μm and a thickness of 25 μm are formed every 1.8 mm. The shadow mask is fixed to a stainless steel frame 34 having the same outer shape and a width of 4 mm.

For the second electrode patterning, a shadow mask having a structure in which a gap 36 exists between one surface 35 of the mask portion 31 and the reinforcing line 33 as shown in FIGS. 16 and 17 was prepared. 120 x 8 shadow mask
4 mm, the thickness of the mask portion is 170 μm, and the length is 1
66 stripe-shaped openings 32 having a width of 770 μm and a width of 770 μm are arranged at a pitch of 900 μm in the horizontal direction. On the mask portion, a mesh-like reinforcing line having a regular hexagonal structure with a width of 45 μm, a thickness of 40 μm, and a distance between two opposing sides of 200 μm is formed. The height of the gap is equal to the thickness of the mask portion and is 170 μm. The shadow mask is fixed to a stainless steel frame 34 having the same outer shape and a width of 4 mm.

The first electrode was patterned as follows. An ITO glass substrate (manufactured by Geomatic) having a 130-nm-thick ITO transparent electrode formed on a 1.1-mm-thick non-alkali glass substrate surface by sputtering deposition was cut into a size of 120 × 100 mm. ITO
A photoresist was applied on the substrate, and the photoresist was patterned by exposure and development by a normal photolithography method. By removing the photoresist after etching the unnecessary portions of ITO, ITO can be 90 mm long,
It was patterned into a stripe shape having a width of 270 μm. As shown in FIG. 18, this stripe-shaped first electrode 2
272 are arranged in the horizontal direction at a pitch of 00 μm.

The spacer was formed as follows. 40
% Methacrylic acid, 30% methyl methacrylate, and 30% styrene by adding 0.4 equivalent of glycidyl methacrylate to the carboxyl group of the copolymer to form an acrylic having a side chain carboxyl group and an ethylenically unsaturated group. A copolymer was obtained. 50 parts by weight of this acrylic copolymer and a bifunctional urethane acrylate oligomer (UX-410, manufactured by Nippon Kayaku Co., Ltd.) as a photoreactive compound
1) 20 parts by weight of hydroxypivalic acid ester neopentyl glycol diacrylate (HX-220, manufactured by Nippon Kayaku Co., Ltd.) as an acrylic monomer, and 200 parts by weight of cyclohexane were added thereto, followed by stirring at room temperature for 1 hour to obtain a resin component. A solution was obtained. Diethylthioxanthone (Nippon Kayaku Co., Ltd., DE
TX-S) 8 parts by weight, sensitizer p-dimethylaminobenzoic acid ethyl ester (Nippon Kayaku Co., Ltd., EPA) 3 parts by weight, and an azo-chromium complex oil-soluble dye methyl ethyl ketone / methyl as a colorant A 30% by weight solution of isobutyl ketone (3804T, manufactured by Orient Chemical Co., Ltd.) and a phthalocyanine-based black pigment were added, and the mixture was stirred at room temperature for 20 minutes to obtain a photosensitive black paste.

This photosensitive black paste was applied on the ITO substrate by spin coating, and prebaked at 80 ° C. for 5 minutes in a nitrogen atmosphere in a clean oven. Further, the coating film was exposed to ultraviolet light through a photomask to photo-cure the desired portion, and 0.4% by volume of 2-vol.
Development was carried out with an aminoethanol aqueous solution. Finally, the patterned coating film is heated at 120 ° C. in a clean oven.
After baking for 30 minutes, the spacer 4 orthogonal to the first electrode was formed as shown in FIGS. The black spacers have a length of 90 mm, a width of 150 μm, and a height of 4 μm, and are arranged in a horizontal direction at a pitch of 900 μm. Further, this spacer had good electric insulation.

After washing the ITO substrate on which the spacer was formed, it was set in a vacuum evaporation machine. In addition, the three shadow masks for the light emitting layer, the shadow mask 1 for the second electrode,
The sheets were set in a vacuum evaporation machine. In the present vacuum evaporation machine, the above four types of shadow masks can be exchanged so that each can be aligned with the substrate in a vacuum with an accuracy of about 10 μm.

The thin film layer was formed as follows by a vacuum deposition method using a resistance wire heating method. Note that the degree of vacuum at the time of vapor deposition was 2 × 10 −4 Pa or less, and the substrate was rotated with respect to the vapor deposition source during vapor deposition.

First, in the arrangement shown in FIG. 19, copper phthalocyanine was 20 nm, and bis (N-ethylcarbazole) was 200 n, as indicated by a quartz crystal resonator type film thickness monitor.
The hole transport layer 5 was formed by vapor deposition on the entire surface of the m substrate.

Next, a first light-emitting layer shadow mask was arranged in front of the substrate so that they were in close contact with each other, and a ferrite plate magnet (YBM-1B, manufactured by Hitachi Metals, Ltd.) was arranged behind the substrate. At this time, as shown in FIGS. 20 and 21, the first electrode 2 is located at the center of the stripe-shaped opening 32 of the shadow mask, and the reinforcing line 33 coincides with the position of the spacer 4. Aligned. In this state, an 8-hydroxyquinoline-aluminum complex (Alq3) was deposited to a thickness of 30 nm to pattern the G light emitting layer. Next, in the same manner as in the patterning of the G light emitting layer, a 1 wt%
Alq3 doped with 4- (dicyanomethylene) -2-methyl-6- (paradimethylaminostyryl) -4-pyran (DCM) was evaporated to a thickness of 30 nm to pattern the R light emitting layer. Further, similarly, using a third light-emitting layer shadow mask, 4,4′-bis (2,2′-diphenylvinyl) biphenyl (DPVBi) was deposited to a thickness of 30 nm.
The B light emitting layer was patterned by vapor deposition.

Further, in the arrangement shown in FIG. 22, DPVBi was deposited to 90 nm and Alq3 was deposited to 30 nm to form an electron transport layer 7 on the entire surface of the substrate. Thereafter, the thin film layer was exposed to lithium vapor to dope (0.5 nm in film thickness conversion).

The second electrode was formed as follows by a vacuum deposition method using a resistance wire heating method. The degree of vacuum at the time of vapor deposition was 3 × 10 −4 Pa or less, and the substrate was rotated with respect to two vapor deposition sources during vapor deposition.

Similarly to the patterning of the light emitting layer, a shadow mask for the second electrode was arranged in front of the substrate so that they were in close contact with each other, and a magnet was arranged behind the substrate. At this time, as shown in FIG. 23 and FIG.
Both are aligned so as to match the position of No. 1. In this state, the second electrode 8 was patterned by depositing aluminum to a thickness of 400 nm.

Finally, in the arrangement shown in FIG. 22, silicon monoxide was deposited on the entire surface of the substrate by a 200 nm electron beam evaporation method to form a protective layer.

As described above, as schematically shown in FIGS. 1 to 3, the width is 270 μm, the pitch is 300 μm, and the number is 27.
A thin film layer 10 including a patterned RGB light emitting layer 6 is formed on the two ITO striped first electrodes 2,
A width of 750 μm and a pitch of 9 so as to be orthogonal to the first electrode.
A simple matrix type color light-emitting device in which 66 stripe-shaped second electrodes 8 of 00 μm were arranged was fabricated. Since the three light emitting regions of RGB form one pixel, the present light emitting device has 90 × 66 pixels at a 900 μm pitch.

Each of the stripe-shaped second electrodes had a sufficiently low electrical resistance over a length of 100 mm without being separated by the reinforcing lines of the shadow mask. On the other hand, there was no short circuit between the second electrodes adjacent in the width direction, and the electrodes were completely insulated.

Each of the light-emitting regions emitted light of a size of 270 × 750 μm and RGB independently. By driving this light-emitting device line-sequentially, clear pattern display and multi-color display were possible. Further, as shown in FIG. 4, the display contrast was improved as compared with Comparative Example 1 because the black spacer was disposed in a part of the non-light emitting region.

Example 2 The procedure was the same as in Example 1 until the hole transport layer was formed.
Next, a first light-emitting layer shadow mask was arranged in front of the substrate so that they were in close contact with each other, and a ferrite plate magnet (YBM-1B, manufactured by Hitachi Metals, Ltd.) was arranged behind the substrate. On this occasion,
As shown in FIGS. 20 and 21, the stripe-shaped first electrode 2 is positioned at the center of the stripe-shaped opening 32 of the shadow mask, and the reinforcing line 33 is aligned with the position of the spacer 4. ing. In this state, Al
By depositing q3 at a thickness of 30 nm, the G light emitting layer was patterned. Next, in the same manner as in the patterning of the G light emitting layer, a 1 wt% DC
Alq3 doped with M was deposited to a thickness of 30 nm to pattern the R light emitting layer. Note that the third light-emitting layer shadow mask was not used, and the B light-emitting layer was not patterned in this example.

Further, in the arrangement as shown in FIG. 22, a 90 nm DPVBi film and a 30 nm film of Alq3 were deposited on the entire surface of the substrate to form an electron transporting layer 7 also serving as a B light emitting layer. Thereafter, the thin film layer was exposed to lithium vapor to dope (0.5 nm in film thickness conversion). Thereafter, patterning of the second electrode and formation of the protective layer were performed in the same manner as in Example 1.

As described above, as schematically shown in FIGS. 25 to 27, the patterned RG light emitting layers 6 and B are formed on the 272 ITO stripe-shaped first electrodes 2 having a width of 270 μm and a pitch of 300 μm. A simple matrix type color light emitting device in which a thin film layer 10 including an electron transporting layer 7 also serving as a light emitting layer is formed, and 66 stripe-shaped second electrodes 8 having a width of 750 μm and a pitch of 900 μm are arranged orthogonally to the first electrode. The device was made. Since the three light emitting regions of RGB form one pixel, the present light emitting device
It has 90 × 66 pixels at a pitch of μm.

As in Example 1, each of the stripe-shaped second electrodes had a sufficiently low resistance in the longitudinal direction, and there was no short circuit.

Each of the light-emitting areas emitted light of a size of 270 × 750 μm and RGB independent colors. By driving this light-emitting device line-sequentially, it was possible to perform clear pattern display and multi-color display as in the first embodiment. Further, as shown in FIG. 4, the display contrast was improved as compared with Comparative Example 1 because the black spacer was disposed in a part of the non-light emitting region.

Comparative Example 1 First, the ITO of the first electrode was patterned in the same manner as in Example 1.

Next, a spacer was formed as follows. Polyimide photosensitive coating agent (Toray Co., Ltd.
UR-3100) is applied on an ITO substrate by spin coating, and then dried under a nitrogen atmosphere in a clean oven.
Prebaked at 0 ° C for 1 hour. Further, the coating film was exposed to ultraviolet light through a photomask to light cure a desired portion, and developed using a developer (DV-505, manufactured by Toray Industries, Inc.). Finally, apply the patterned coating film in a clean oven at 180 ° C. for 30 minutes,
Baking was performed at 30 ° C. for 30 minutes to form a spacer 4 orthogonal to the first electrode as shown in FIGS. This translucent spacer has a length of 90 mm, as in Example 1.
It has a width of 150 μm and a height of 4 μm, and is arranged horizontally at a pitch of 900 μm. Further, this spacer had good electric insulation.

A simple matrix type color light emitting device was manufactured in the same manner as in Example 1 except for the above. 3 consisting of RGB
Since one light-emitting region forms one pixel, the present light-emitting device has 9 pixels.
It has 90 × 66 pixels at a pitch of 00 μm.

As in the case of Example 1, each of the stripe-shaped second electrodes had a sufficiently low resistance in the longitudinal direction, and there was no short circuit. Each light-emitting region emitted light of a size of 270 × 750 μm and RGB independent colors. By driving the light emitting device line-sequentially, it was possible to display a clear pattern and to realize multi-color display. However, since the non-light emitting area was translucent, the display contrast was worse than in Examples 1 and 2.

Example 3 In the same manner as in Example 1, ITO of the first electrode was 90 m long.
After patterning into a stripe shape having a width of 280 μm and a width of 280 μm, the photoresist was removed. As in Example 1,
This striped first electrode is 300 μm on a glass substrate.
272 are arranged in the horizontal direction at the pitch.

Next, a spacer was formed as follows. First, after adjusting the concentration of the photosensitive black paste used in Example 1, it was applied on the ITO substrate by spin coating, and the same photolithography process as in Example 1 was carried out, as shown in FIGS. A first spacer 3 in a matrix was formed. This black spacer has a height of 0.5μ
m and 270 × 750 without this spacer
The first electrode is exposed in a region having a size of μm. The first spacer was formed so as to cover the end of the first electrode at 5 μm.

Further, a second spacer 4 was formed by the same photolithography process as in Example 1 using the photosensitive black paste. This black spacer is shown in FIG.
As shown in (10) to (10), the first spacer is formed on a portion orthogonal to the first electrode in the first spacer, and has a length of 90 mm, a width of 130 μm, a height of 4 μm, and 900
67 are arranged in the horizontal direction at a pitch of μm. The above two types of spacers each had good electrical insulation.

A simple matrix type color light emitting device was manufactured in the same manner as in Example 1 except for the above. 3 consisting of RGB
Since one light-emitting region forms one pixel, the present light-emitting device has 9 pixels.
It has 90 × 66 pixels at a pitch of 00 μm. As in Example 1, each of the stripe-shaped second electrodes had a sufficiently low resistance in the longitudinal direction, and there was no short circuit.

Each of the light-emitting regions emitted light of a size of 270.times.750 .mu.m in an independent color of RGB. By driving the light emitting device line-sequentially, it was possible to display a clear pattern and to realize multi-color display. Further, the light emitting region was surrounded by the black spacer as shown in FIG. 11, so that the display contrast was further improved as compared with Examples 1 and 2.

Example 4 A shadow mask having a structure in which a mask portion and a reinforcing line shown in FIG. 15 were formed on the same plane was prepared for patterning a light emitting layer. 120 x 8 shadow mask
4 mm, the thickness of the mask portion 31 is 25 μm, and 272 stripe-shaped openings 32 having a length of 64 mm and a width of 100 μm are arranged at a pitch of 300 μm in the horizontal direction. Each stripe-shaped opening has a width of 20 μ orthogonal to the opening.
The reinforcing wires 33 having a thickness of 25 μm and a thickness of 25 μm are formed every 1.8 mm. The shadow mask has the same outer shape and width 4
mm is fixed to a stainless steel frame 34.

For patterning the second electrode, a shadow mask having a structure in which a gap 36 exists between one surface 35 of the mask portion 31 and the reinforcing line 33 shown in FIGS. 16 and 17 was prepared. The outline of the shadow mask is 120 x 84m
m, the thickness of the mask portion is 100 μm, and the length is 100 μm.
200 stripe-shaped openings 32 having a width of 245 μm and a width of 300 μm are arranged in the horizontal direction. On the mask portion, a mesh-like reinforcing line having a regular hexagonal structure having a width of 40 μm, a thickness of 35 μm, and a distance between two opposing sides of 200 μm is formed. The height of the gap is equal to the thickness of the mask portion and is 100 μm. In addition, the shadow mask is a stainless steel frame 3 having the same outer shape and a width of 4 mm.
4 is fixed.

First, ITO of the first electrode was patterned into a stripe shape having a length of 90 mm and a width of 70 μm in the same process as in Example 1. As shown in FIG. 18, this stripe-shaped first electrode 2 has a horizontal pitch of 816 at a pitch of 100 μm.
Book is arranged.

Next, the same photosensitive black paste as in Example 1 was used, and the same photolithography process as in Example 1 was carried out to obtain FIG.
A spacer 4 perpendicular to the first electrode as shown in FIGS. The transparent spacers have a length of 90 mm, a width of 60 μm, and a height of 4 μm, and are arranged 201 at a pitch of 300 μm in the horizontal direction. Further, this spacer had good electric insulation.

Using the above shadow mask, a simple matrix type color light emitting device was manufactured in the same manner as in Example 1. In this light emitting device, as schematically shown in FIGS. 1 to 3, the width of 70 μm, the pitch of 100 μm, and the number of 816 I
A thin film layer 10 including a patterned RGB light emitting layer 6 is formed on the TO stripe-shaped first electrode 2, and has a width of 240 μm and a pitch of 300 μm perpendicular to the first electrode.
200 of the stripe-shaped second electrodes 8 are arranged.
Since the three light emitting regions of RGB form one pixel, the present light emitting device has 272 × 200 pixels at a pitch of 300 μm.

As in the case of Example 1, each of the stripe-shaped second electrodes had a sufficiently low resistance in the longitudinal direction, and there was no short circuit.

Each of the light-emitting regions emitted light of independent colors of RGB with a size of 70 × 240 μm. By driving this light-emitting device line-sequentially, it was possible to display a clear pattern with good display contrast and to make it multi-colored. Example 5 Performed in the same manner as in Example 4 until the spacer was formed. Was.
First, in the arrangement as shown in FIG.
m, N, N'-diphenyl-N, N'-dinaphthyl-
1,1'-diphenyl-4,4'-diamine (NPD)
Was deposited over the entire surface of the substrate to form a hole transport layer 5.

Next, a first light-emitting layer shadow mask was arranged at the front of the substrate so that they were in close contact with each other, and a ferrite plate magnet (YBM-1B, manufactured by Hitachi Metals, Ltd.) was arranged at the rear of the substrate. At this time, as shown in FIGS. 20 and 21, the stripe-shaped first electrode 2 is located at the center of the stripe-shaped opening 32 of the shadow mask, the reinforcing line 33 matches the position of the spacer 4, and the reinforcing line is formed. Both are aligned so that the and the spacers are in contact. In this state, 0.3
wt% of 1,3,5,7,8-pentamethyl-4,4-
43 nm of Alq ₃ doped with difluoro-4-bora 3a, 4a-diaza-s-indacene (PM546)
The G light emitting layer was patterned by vapor deposition. Next, the G
Using a second light-emitting layer shadow mask in the same manner as the patterning of the light-emitting layer, 1 wt% of 4- (dicyanomethylene) -2-methyl-6- (julolidylstyryl) -pyran (DCJT) was doped. Alq ₃ at 30 nm
The R light emitting layer was patterned by vapor deposition. Further, similarly, using the third light emitting layer shadow mask, the DPV
Bi was deposited to a thickness of 40 nm to pattern the B light emitting layer. Each of the light emitting layers is disposed every third stripe-shaped first electrode 2 and completely covers the exposed portion of the first electrode.

Further, in the arrangement shown in FIG. 22, DPVBi was deposited to a thickness of 70 nm and Alq ₃ was deposited to a thickness of 20 nm on the entire surface of the substrate to form an electron transporting layer 7. After that, the thin film layer 10 was exposed to lithium vapor for doping (0.5 nm in equivalent film thickness).

Thereafter, patterning of the second electrode and formation of the protective layer were performed in the same manner as in Example 4.

As described above, the same 30s as in the fourth embodiment are used.
A simple matrix type color light emitting device having 272 × 200 pixels at a pitch of 0 μm was prepared. Each light emitting area is 70 ×
Light was emitted uniformly in a color independent of RGB at a size of 240 μm. By driving this light-emitting device line-sequentially, it was possible to display a clear pattern and multi-color the same as in the fourth embodiment. Further, the luminescent color purity was improved by doping the luminescent layer as compared with Example 4.

[0075]

The organic electroluminescent device of the present invention has the following effects.

(1) Since at least a part of the spacer having a height exceeding the thickness of the thin film layer is black, the display contrast is improved.

(2) The second electrode can be patterned using a spacer having a height exceeding the thickness of the thin film layer. For example, by using the spacer as it is, patterning by the partition method becomes possible. Also,
In the patterning by the mask method, the shadow mask adheres to the spacer having a height exceeding the thickness of the thin film layer, so that the thin film layer is not damaged, so that the characteristics of the organic electroluminescent element are not deteriorated. This effect is particularly great when the adhesion between the substrate and the shadow mask is improved by magnetic force or when the two are aligned.

[Brief description of the drawings]

FIG. 1 is a plan view showing an example of the organic electroluminescent device of the present invention.

FIG. 2 is a sectional view taken along the line XX ′ of FIG. 1;

FIG. 3 is a sectional view taken along line YY ′ of FIG. 1;

FIG. 4 is a plan view of FIG. 1 as seen from behind.

FIG. 5 is a plan view showing another example of the organic electroluminescent device of the present invention.

FIG. 6 is a sectional view taken along the line XX ′ of FIG. 5;

FIG. 7 is a sectional view taken along line YY ′ of FIG. 5;

FIG. 8 is a plan view showing another example of the organic electroluminescent device of the present invention.

FIG. 9 is a sectional view taken along the line XX ′ of FIG. 8;

FIG. 10 is a sectional view taken along the line YY ′ of FIG. 8;

FIG. 11 is a plan view of FIG. 8 as seen from the back.

FIG. 12 is a plan view showing another example of the organic electroluminescent device of the present invention.

FIG. 13 is a sectional view taken along the line XX ′ of FIG. 12;

FIG. 14 is a sectional view taken along line YY ′ of FIG. 12;

FIG. 15 is a plan view showing a shadow mask for patterning a light emitting layer used in Example 1.

FIG. 16 is a plan view showing a shadow mask for patterning a second electrode used in Example 1.

FIG. 17 is a sectional view taken along the line XX ′ of FIG. 16;

FIG. 18 is a plan view showing a first electrode pattern patterned in Example 1.

FIG. 19 is a cross-sectional view along XX 'for explaining the method of forming the hole transport layer in Example 1.

FIG. 20 is an XX ′ cross-sectional view illustrating an example of a light emitting layer patterning method in Example 1.

FIG. 21 is a YY ′ cross-sectional view illustrating an example of a light emitting layer patterning method in Example 1.

FIG. 22 is an XX ′ cross-sectional view for explaining the method for forming the electron transport layer in Example 1.

FIG. 23 is a cross-sectional view along XX 'for explaining an example of the second electrode patterning method in the first embodiment.

FIG. 24 is a YY ′ cross-sectional view for explaining an example of the second electrode patterning method in the first embodiment.

FIG. 25 is a plan view showing the organic electroluminescent device manufactured in Example 2.

FIG. 26 is a sectional view taken along the line XX ′ of FIG. 25;

FIG. 27 is a sectional view taken along the line YY ′ of FIG. 25.

FIG. 28 is a cross-sectional view showing an example of a conventional organic electroluminescent device.

FIG. 29 is a sectional view showing an example of a conventional organic electroluminescent device.

FIG. 30 is a sectional view taken along the line XX ′ of FIG. 29;

FIG. 31 is a sectional view taken along line YY ′ of FIG. 29;

FIG. 32 is a plan view of FIG. 29 viewed from the back;

[Explanation of symbols]

 Reference Signs List 1 substrate 2 first electrode 3 first spacer 4 spacer (second spacer) 5 hole transport layer 6 light emitting layer 7 electron transport layer 8 second electrode 9 drive source 10 thin film layer 11 hole transport material 12 light emitting material 13 Electron transporting material 14 Second electrode material 15 Electrically conductive portion 16 Light emitting region 17 Non-light emitting region 30 Shadow mask 31 Mask portion 32 Opening 33 Reinforcement line 34 Frame 35 One surface of mask portion 36 Gap

Claims (8)

[Claims] 1. A first electrode formed on a substrate, a thin film layer including at least a light emitting layer made of an organic compound, formed on the first electrode, and a plurality of second layers formed on the thin film layer. An organic electroluminescent device having a plurality of light emitting regions on the substrate, wherein a spacer having a height at least partially exceeding the thickness of the thin film layer is formed on the substrate, and An organic electroluminescent device, wherein at least a part of the spacer is black. 2. The organic electroluminescent device according to claim 1, wherein at least a portion of the spacer in contact with the substrate or the first electrode is black. 3. The organic electroluminescent device according to claim 1, wherein at least a portion of the spacer in contact with the substrate or the first electrode is a transparent layer, and a black layer is laminated thereon. . 4. The organic electroluminescent device according to claim 1, wherein the light emitting region is surrounded by at least a part of the spacer which is black. 5. The organic electroluminescent device according to claim 1, wherein a spacer having a height exceeding the thickness of the thin film layer is formed between the second electrodes. 6. The method according to claim 1, wherein a second spacer having a height exceeding a thickness of the thin film layer is laminated on the first spacer in contact with the substrate or the first electrode.
The organic electroluminescent device according to claim 1. 7. The organic electroluminescent device according to claim 1, wherein at least a portion of the spacer in contact with the substrate or the first electrode has electrical insulation. 8. The first electrode is a plurality of stripe-shaped electrodes arranged on a substrate at a horizontal interval, and the second electrode is arranged at a horizontal interval at a distance from the first electrode. The organic electroluminescent device according to claim 1, wherein the plurality of striped electrodes intersect with each other.