JP2001085162A - Organic light emitting element and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an organic light emitting element preventing a short circuit between electrode films and causing entire organic layers including the corners of each pixel to emit light uniformly, and a method for manufacturing it. SOLUTION: This organic light emitting element has a substrate 1, a first electrode 2, a framing wall 5 surrounding the four sides of each pixel, organic layers 3 formed on the electrode, and a second electrode 4 formed on the organic layers. At least one of the electrode layers is formed by solidification of a solution or dispersion containing an organic material and injected inside the framing wall, and the inside corners of the framing wall are rounded so that the inside corners of the framing wall are filled with the injected solution or dispersion containing the organic material.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an organic light emitting device used as a pixel of a display and a method of manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, a coating method such as a spin coating method, a dipping method, and a doctor blade method has been used for manufacturing an organic LED element by a wet method. In these methods, a pixel is formed by patterning a light emitting layer. Was difficult to colorize. However, in recent years, as one solution to this problem, there has been proposed a method of forming a light-emitting layer by patterning by an ink-jet method (JP-A-Hei.
No. 10-12377, Appl, Phys. Lett. No. 72, p. 519, 1998
Year) .

Further, after patterning an anode formed on a transparent substrate into an anode group, a bank is formed between the anodes, and a charge injection / transport layer and / or a light emitting layer is formed between the banks in a liquid phase. An electroluminescent device having a structure in which a cathode is formed thereon is disclosed (JP-A-11-87062). In this electroluminescent device, since the critical surface tension γc of the constituent material of the bank is smaller than the surface tension γ of the liquid phase, the bank has water / oil repellency. Therefore, the material forming these layers does not extend between the pixels, so that the electric leakage between the pixels is prevented. In addition, even if the material liquid for forming the light emitting layer is discharged using an inkjet head, the surface tension γ of these solvents is usually 30 dyne / c.
Since it is not less than m and the wetting of the bank is small, it fits within the pixel and does not contaminate adjacent pixels. Therefore, vivid color display can be achieved by reliable light emission of each pixel.

[0004]

However, by making the critical surface tension γc of the constituent material of the bank smaller than the surface tension γ of the liquid phase forming the charge injection transport layer and / or the light emitting layer, the pixel in the bank can be reduced. , The liquid for forming the light-emitting layer does not penetrate to the corners in the banks that partition the pixels, and the first electrode film is exposed. Therefore, when the second electrode film is formed on the organic layer formed by solidifying the liquid for forming the light emitting layer, a short circuit easily occurs between the first electrode film and the second electrode film. In order to solve this problem, a method of forming the second electrode film only in a portion where the organic layer is formed, or a method of combining a process of forming an organic layer by a dry process such as a vacuum deposition method and a wet method are also available. Although it is possible, these methods significantly reduce the aperture ratio of the organic layer.

The present invention has been made in view of the above-mentioned problems, and an organic light-emitting element which prevents a short circuit between electrode films and uniformly emits light in the entire organic layer including the corners of each pixel, and an organic light-emitting element therefor. A manufacturing method is provided.

[0006]

According to the present invention, a substrate, first electrodes (films) arranged vertically and horizontally on the surface thereof, a frame wall surrounding four circumferences of each pixel, and an upper surface of the electrode film are provided. In an organic light emitting device having an organic layer formed on the organic layer and a second electrode film group formed on the organic layer, at least one organic layer is a solution containing an organic material injected into the inside of the frame wall. Alternatively, the dispersion liquid is formed by solidification, and the frame wall is formed by cutting off the corners so that the inside corners of the frame wall are filled with the solution or dispersion containing the injected organic material. Is provided.

That is, the present inventors have conducted intensive studies on the shapes of the corners on the inside of the frame wall so as not to form a gap between the organic layer and the corners on the inside of the frame wall. as a result,
By taking a corner inside the frame wall, when a solution or dispersion liquid containing an organic material (hereinafter abbreviated as “organic material liquid”) is injected into the inside of the frame wall, the organic material liquid is When the corners are filled and the organic material liquid solidifies, an organic layer having no gap is formed between the corners and the inside corners of the frame wall. Therefore,
It is possible to prevent the second electrode film from entering the gap between the frame wall and the organic layer and causing a short circuit with the first electrode film. Furthermore, it is possible to easily and inexpensively manufacture an organic light-emitting device having excellent display quality and a high aperture ratio by a wet method.

According to another aspect of the present invention, a first electrode film group is vertically and horizontally arranged on a surface of a substrate, four circumferences of each pixel are surrounded by a frame wall, and an organic material liquid is injected onto the electrode film. Forming at least one organic layer, and then forming a second electrode film group.
A method for manufacturing an organic light-emitting device is provided, wherein the inner corner of the frame wall is rounded so as to be filled with an organic material liquid.

The critical surface tension in the present invention means "Zisman's critical surface tension" which defines the degree of "sliminess" of a liquid on the surface of a solid. That is, polar organic liquids, saturated hydrocarbons, water, etc. having various surface tensions are dropped on the surface of most solids such as organic polymers and organic compounds having a low energy surface, and their contact angles θ Are measured, and these cos θ are plotted against the surface tension γ [dyne / cm 2] of each liquid, and the surface tension value γc at the point where the obtained approximate straight line intersects the horizontal line at the contact angle θ = 0 ° dyne / cm 2] is the critical surface tension in the present invention. The surface tension of the organic material liquid in the present invention is a value of the surface tension γ [dyne / cm] expressed as a work [erg] for the liquid to form a surface having a unit area [cm ² ].
Means

By selecting both the organic material liquid and the material of the frame wall so that the critical surface tension of the frame wall is smaller than the surface tension of the organic material liquid injected into the inside of the frame wall, the organic material liquid is removed. When injecting into the inside of the frame wall, the inside wall surface of the frame wall becomes water repellent or oil repellent to the organic material liquid,
That is, since the organic material liquid does not wet the inside of the upper part of the frame wall, the organic material liquid does not spread over adjacent pixels along the frame wall, and a short circuit between pixels can be prevented.

Further, since contamination of the adjacent pixels by the organic material liquid is prevented, problems such as color mixing can be avoided, and the entire organic layer can emit light uniformly. The difference between the critical surface tension of the inner wall surface of the frame wall at 20 ° C. and the surface tension of the organic material liquid at 20 ° C. is preferably 5 dyne / cm or more. Within this range, a convex meniscus is formed because the adhesive force of the organic material liquid to the frame wall is small.

On the other hand, by selecting the materials of the first electrode film and the organic material liquid so that the critical surface tension of the first electrode film becomes larger than the surface tension of the organic material liquid, the liquid of the organic material liquid with respect to the electrode film is reduced. Thus, the organic material liquid can be filled up to the lower corner of the inner corner of the frame wall. as a result,
With the high aperture ratio, short circuits between pixels and between electrode films can be prevented, and extremely vivid color display can be achieved. The difference between the critical surface tension of the first electrode film at 20 ° C. and the surface tension of the organic material liquid at 20 ° C. is preferably 5 dyne / cm or more.

The pixel in the present invention means a pixel in the case of a monochrome or zone color display, and means a sub-pixel in the case of a multi-color or full-color display. Although the shape of the pixel is not particularly limited, a polygonal shape, a circular shape, and an elliptical shape are exemplified. In order to form a uniform film up to the corners of the pixels, it is preferable that the corners of the pixels be concave toward the center when viewed from above.

Known methods for injecting the organic material liquid into the inside of the frame wall include a spin coating method, an ink jet method for discharging the organic material liquid from an ink jet head, and a nozzle injection method for discharging the organic material liquid from a nozzle or a needle. Method can be adopted.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to FIGS.
Embodiments of an organic light emitting device and a method for manufacturing the same according to the present invention will be described, but the present invention is not limited thereto.

FIG. 1 shows a basic structure of an organic LED device as an organic light emitting device of the present invention. In FIG. 1, an organic LED element 10 includes a polarizing plate 7, a substrate 1, a first electrode film 2, an organic layer 3, a second electrode film 4, and a sealing film 6, which are laminated in this order, and a frame wall 5 is formed. Surrounding the organic layer 3,
One pixel is formed. The organic layer 3 is formed by solidifying a convex meniscus when the organic material liquid is injected. As the substrate 1, a quartz substrate, a glass substrate, a plastic substrate, or the like is used.

The first electrode film 2 and the second electrode film 4 are an electrode pair forming a positive electrode and a negative electrode.
When forming a display consisting of
When the electrode film 2 is transparent, light emitted from the organic layer 3 is emitted from the substrate 1 side. Therefore, in order to increase the luminous efficiency, the second electrode film 4 must be a reflective electrode,
It is preferable to have a reflective film on the side of the electrode film 4 not adjacent to the organic layer 3. Conversely, the second electrode film 4 may be made of a transparent material, and light emitted from the organic layer 3 may be emitted from the second electrode film 4 side. In this case, it is preferable that the first electrode film 2 is a reflective electrode, the substrate 1 is a reflective substrate, or a reflective film is provided between the first electrode film 2 and the substrate 1.

As the transparent electrode, CuI, ITO, Sn
A transparent electrode such as O ₂ , ZnO, CuAlO ₂ is used. Further, as the reflective electrode, a metal such as aluminum and calcium, an alloy such as magnesium-silver and lithium-aluminum, a laminated film of metals such as magnesium / silver,
A laminated film of an insulator such as lithium fluoride / aluminum and a metal is used. The deflection plate 7 is provided outside the substrate 1 in order to obtain a good contrast in the display. The sealing film 6 (or the sealing substrate) is the second electrode film 4
It is provided to prevent damage or deterioration.

The corner of the frame wall 5 is rounded so that an inner corner thereof is filled with an organic material liquid described later, and the organic material liquid is solidified according to the shape of the inside of the frame wall 5, and the organic layer 3 is formed. Is formed, the pixel is determined by the shape of the frame wall 5. 2A to 2C show an example of the shape of the corner 51 inside the frame wall 5 forming each pixel (51a to 51c).
c) It is a horizontal sectional view. The shape of the corner 51 is 51
It may be one that is “squared” by one or a plurality of straight lines as in a and 51b, or may be one that is “squared” by a curve concave toward the center as in 51c. Further, the “square” of the corners 51 at the four corners may be different in size or different in shape.

The frame wall 5 can be manufactured by photolithography. In this case, a photomask of the frame wall 5 having a corner portion 51 having a desired shape is prepared, a resist film is formed, and then etching is performed using the photomask to obtain a desired “sharpened” frame wall. 5 can be formed. The frame wall 5 is made of a material having a critical surface tension smaller than the surface tension of the organic material liquid injected into the inside of the frame wall 5, and by suppressing “wetting” between the organic material liquid and the inside of the frame wall 5. The organic material liquid is formed of an organic material such that a convex meniscus is formed on the upper surface thereof. Therefore, the material of the frame wall 5 is selected in relation to the surface tension of the organic material liquid.

Preferred materials for forming the frame wall 5 are listed below. The values in parentheses indicate the critical surface tension value γc [dyne / cm 2] of the frame wall material at 20 ° C. Frame wall 5
Examples of preferable materials include, for example, perfluorooctylethyl methacrylate (15 dyne / cm 2), polypropylene hexafluoride (16 dyne / cm 2), and polytetrafluoroethylene (18dy
ne / cm), poly (ethylene trifluoride) (22 dyne / cm), polydimethylsiloxane (24 dyne / cm), polyvinylidene fluoride (25 dyne / cm), polyethylene (31 dyne / cm), polystyrene (33 dyne / cm), manufactured by Asahi Glass CYTOP [trademark] (19 dyne / cm 2). Further, using a positive resist as a host, KBM7103 manufactured by Shin-Etsu Chemical Co., Ltd.
(20 dyne / cm), 7803 (15 dyne / cm) KP801M
A mixture of (8 dyne / cm) as a guest is also a preferred material.

The frame wall 5 only needs to be formed at least in a part between pixels. The structure of the frame wall 5 may be a single-layer structure or a multilayer structure in which thin films are superimposed. The organic material liquid is preferably insoluble or hardly soluble in the solvent of the organic material liquid. It is also preferable to use a material for a black matrix in order to improve display quality as a display. Alternatively, after forming the frame wall 5 using these materials, plasma treatment, UV treatment, gas treatment, or the like is performed to obtain the critical surface tension γ of the surface of the frame wall 5.
The value of c may be controlled.

The inner wall surface of the frame wall 5 is formed by using the above-described material or by performing the above-described processing, but a more effective convex meniscus is formed. In order to form, the difference between the critical surface tension γc of the material of the frame wall 5 and the surface tension γ of the organic material liquid to be the organic layer 3 described later is preferably at least 5 dyne / cm or more. The frame wall 5 can further prevent the organic layer 3 from being damaged by the close contact of the shadow mask when the second electrode film 4 is formed using the shadow mask,
By setting the shape of the frame wall 5 to an appropriate shape, for example, a reverse taper shape, the patterning of the second electrode film 4 becomes possible without using a shadow mask.

The organic layer 3 has a structure having at least one organic layer, and may have a single-layer structure consisting of only the organic layer or a multilayer structure of the charge transport layer and the organic layer. Moreover, you may insert a buffer layer as needed. In the case of a multilayer structure of the charge transport layer and the organic layer,
The charge transport layer and the organic layer may each be a single layer, or a plurality of the above layers may be used. Also, the organic layer 3
In the case of a multilayer structure including a plurality of organic layers, at least one of the organic layers needs to be formed by a wet method. At this time, the other organic layer may be formed by a wet method, or may be formed by a dry process such as a vacuum evaporation method.

The material of the organic layer 3 is not particularly limited as long as it is formed by a wet method capable of forming a thin film from the state of a coating liquid (organic material liquid). Examples of the wet method include various methods of forming a thin film, such as a spin coating method, a dipping method, a doctor blade method, a printing method, an electrodeposition method, or a method of discharging an organic material liquid from an inkjet head, a nozzle or a needle. A method of discharging a coating liquid from an inkjet head, a nozzle or a needle is particularly preferable. Although a suitable material (organic material liquid) is slightly different depending on the method to be adopted, the surface tension γ of the organic material liquid is larger than the critical surface tension γc of the frame wall 5, and furthermore, the critical surface tension γc of the electrode films 2 and 4. It must be smaller.

The organic material liquid used in the wet method can be classified into a light emitting layer forming coating liquid and a charge transporting layer forming coating liquid. Examples of the coating liquid for forming a light emitting layer include known polymer light emitting materials for organic LEDs, for example, poly [2-decyloxy-1,4-phenylene] (DO-PPP), poly [2,
5-bis [2- (N, N, N-triethylammonium) ethoxy] -1,4-phenylene-alto-1,4
- phenylene] dibromide (PPP-NEt ₃ ^+), poly [2- (2'-ethylhexyl oxy) -5-methoxy-1,4-phenylene vinylene] (MEH-PP
V), poly [5-methoxy- (2-propanoxysulfonide) -1,4-phenylenevinylene] (MPS-P
PV), poly [2,5-bis (hexyloxy) -1,
4-phenylene- (1-cyanovinylene)] (CN-P
PV) or the like is dissolved or dispersed in a known solvent,
Alternatively, known low-molecular light-emitting materials for organic LEDs, for example, tetraphenylbutadiene (TPB), coumarin,
Use a coating solution in which Nile Red, an oxadiazole derivative, or the like, and a known polymer material such as polycarbonate (PC), polymethyl methacrylate (PMMA), or polyvinyl carbazole (PVCz) are dissolved or dispersed in a known solvent. be able to. In addition, these coating solutions include
If necessary, additives for pH adjustment, viscosity adjustment, penetration enhancement, leveling, etc., and known hole transport materials for organic LEDs and organic photoconductors (for example, the N, N′-bis- ( 3-methylphenyl) -N, N′-bis- (phenyl) -benzidine (TPD), N, N′-di (naphthalen-1-yl) -N, N′-diphenyl-benzidine (NPD), etc. Electron transporting materials (for example, 3- (4-biphenylyl-4--4-phenylene-5-tert-butylphenyl-1,2,4-triazole (TAZ), tris (8-hydroxyquinolinonato) aluminum (Alq
₃ ) A charge transporting material such as ₃ ) and a dopant such as an acceptor and a donor may be added.

As the coating liquid for forming the charge transport layer, organic LE
Known polymer charge transport materials for D and organic photoconductors (for example, polyaniline (PANI), 3,4-polyethylenedioxythiophene (PEDT), poly [triphenylamine derivative] (Poly-TPD), [Oxadiazole derivative] (Poly-OXZ etc.), PV
A coating liquid in which Cz or the like is dissolved or dispersed in a known solvent, or a known low-molecular-weight charge transporting material for an organic LED or an organic photoconductor (for example, the above-mentioned TPD, NPD, oxadiazole derivative, etc.) A coating solution in which a known polymer material (for example, the above-described PC, PMMA, PVCz, or the like) is dissolved or dispersed in a known solvent can be used. Also,
For these liquids, if necessary, for pH adjustment, viscosity adjustment,
Additives for filling promotion, leveling, surface tension adjustment, etc., and dopants such as acceptors and donors may be added.

When the ink jet method is used, conventional solvents can be used as a solvent for dissolving or dispersing the above-mentioned polymer material. Among these solvents, low vapor pressure solvents such as, for example, Ethylene glycol, propylene glycol, triethylene glycol,
Ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, triethylene glycol monomethyl ether, triethylene glycol monoethyl ether, glycerin, formamide, N-methyl-2
-Pyrrolidone, cyclohexane, 1-propanol, octane, nonane, decane and the like are preferably contained.
The composition ratio of the solid content and the solvent in the light-emitting layer forming coating liquid and the charge transport layer forming coating liquid is preferably adjusted so that the viscosity of the coating liquid at 20 ° C. becomes 10 mPa · s or less, and the surface tension Preferably, γ is adjusted to be at least 40 dyne / cm.

Further, the organic layer 3 can be formed between the electrode film 2 and the electrode film 4 by a conventional dry process, for example, a resistance heating evaporation method, an EB evaporation method, an ion plating method, or the like. As the organic material that can be used in the dry process, a known light emitting material for an organic LED can be used,
The organic layer may be composed of only an organic material, or may contain an additive or the like. As the charge transporting material, known materials for organic LEDs and organic photoconductors can be used. The charge transporting layer may be composed of only the charge transporting material, or may contain additives and the like. May be.

Next, referring to the plan view of FIG.
The arrangement of the organic layer 3 for forming an organic LED display by arranging a plurality of ED elements will be described. Organic layer 3
Includes a red (R) light-emitting pixel 11 and a green (G) light-emitting pixel 1
2 and blue (B) light-emitting pixels 13. The organic LED display 20 of the present invention is configured by arranging these three types of organic layers 3 in a predetermined arrangement pattern or a random pattern in a matrix. Is done.

In FIG. 3A, the light-emitting pixels of the above-described colors are arranged in a stripe shape adjacent to the short side of the frame wall 5 [stripe arrangement]. FIG. 3B shows a mosaic arrangement in which the above-described light emitting pixels of each color are arranged adjacent to each other at the corners of the frame wall 5 in a mosaic pattern. In FIG. 3C, the organic layer 3 (frame wall 5) meanders, and the above-described light-emitting pixels of each color are arranged in a staggered pattern (delta arrangement). Further, as the organic LED display 20, as shown in FIG. 3D, a display (square arrangement) in which the above-described luminescent pixels of each color are regularly arranged is exemplified. In the arrangement of these luminescent pixels, a red (R) luminescent pixel 11, a green (G) luminescent pixel 12
And the number of blue (B) light-emitting pixels 13 is not necessarily
The ratio does not have to be 1: 1: 1. Further, the area of each pixel may be the same, or may be different for each pixel. Instead of three types (three colors), one type (one color) may be used.

The shape of the above-mentioned pixel can be formed by forming the frame wall into a desired shape at the time of manufacturing the frame wall. The method of forming the frame wall is not particularly limited. When forming the wall, it is possible to appropriately control the conditions such as exposure conditions, photomask shape, baking temperature, baking time and the like, and it is also possible to form a groove having a desired frame wall shape. It is also possible to make the mold by bringing the mold into close contact with the substrate, impregnating the formed space with a liquid material for forming the frame wall, filling the space, and then fixing the material.

Next, the first electrode film 2 and the second electrode film 4 corresponding to each pixel will be described with reference to the plan views of FIGS.
The connection method between them will be described. Organic LE of the present invention
As shown in FIG. 4, the D display may have a diagonal stripe electrode configuration in which the first electrode film 2 and the second electrode film 4 sandwiching the organic layer 3 are orthogonal to each other on the common substrate 1. As shown in FIG. 5, the first electrode film 2 or the second electrode film 4 is connected to a thin film transistor 21 (T
It may be connected to the second electrode film 4 or the first electrode film 2 via FT).

[0034]

EXAMPLES Specific examples of the embodiment will be described below.Example 1  First, a glass substrate 1 with ITO having a thickness of 130 nm
Is used as the first electrode film 2 by photolithography.
ITO transparent stripe of 200μm width at 40μm pitch
Make electrodes. Next, a glass substrate 1 with ITO is used as an example.
For example, isopropyl alcohol, acetone, and pure water were used.
Conventional wet cleaning process and UV ozone treatment
Cleaning by conventional dry process such as treatment and plasma treatment
I do. At this time, the critical surface of the ITO surface at 20 ° C
The tension γc was 56 dyne / cm.

Next, a positive resist having a critical surface tension γc at 20 ° C. of 20 dyne / cm was applied on the substrate 1 by spin coating to form a resist film having a thickness of 30 μm. Next, the frame wall 5 is exposed using an exposure mask.
Was prepared. As shown in FIG. 2 (c), the mask for exposure has a corner 51c formed by a curved line having a concave shape toward the center, as shown in FIG. . Next, the resist residue is washed away, and ITO is removed.
A frame wall 5 having a width of 40 μm was formed at a pitch of 540 μm in a direction parallel to the above and at a pitch of 230 μm in a direction perpendicular to ITO.

Then, using a commercially available spin coater, a 3,4-polyethylenedioxythiophene aqueous solution having a surface tension of 43 dyne / cm at 20 ° C. and a thickness of 50
A hole injection layer having a thickness of nm was formed. Next, a commercially available dispenser was used to pattern and apply a light-emitting material that emits red, green, and blue light to form a light-emitting layer having a thickness of 50 nm. Here, a cyanopolyphenylene vinylene precursor was used as a red light emitting material, a polyphenylene vinylene precursor was used as a green light emitting material, and polyparaphenylene was used as a blue light emitting material. At this time, the surface tension γ at 20 ° C. of all the coating liquids was 48 dyne / cm. However,
The cyanopolyphenylenevinylene precursor and the polyphenylenevinylene precursor were converted into cyanopolyphenylenevinylene and polyphenylenevinylene by performing a heat treatment at 150 ° C. for 6 hours in an Ar atmosphere after forming the film. The arrangement pattern of the light emitting layer is shown in FIG.
Was used.

Next, using a shadow mask having a thickness of 0.2 μm, a width of 510 μm, and a pitch of 540 μm, Al and Li were used.
Is co-evaporated to form AlL as the second electrode film 4.
An i-alloy electrode was formed. Finally, sealing was performed using an epoxy resin. The organic LED display manufactured as described above includes a first electrode film 2 and a second electrode film 4 between the first electrode film 2 and the second electrode film 4.
No short circuit occurred between the electrode films 2 and between the second electrode films 4, and non-uniform light emission from the edge of the pixel portion due to non-uniform thickness of the light emitting layer and the charge transport layer was not observed. . Further, by applying a pulse voltage of 30 V to this display, uniform light emission was obtained from all the pixels.

[0038]Example 2  Instead of dispenser as a method of discharging organic material liquid
Other than using a commercially available inkjet printer
Produced an organic LED display in the same manner as in Example 1.
Made. Organic material liquid by inkjet printer
As shown in FIG. 6, the ejection is performed in a predetermined arrangement pattern.
3 corresponding to the interval of the frame wall 5 formed in
An ink jet head 24 is arranged and these ink jets are
Red (R) light-emitting pixel 11, green
(G) Light-emitting pixel 12 and blue (B) light-emitting pixel 13 are frame walls
5 on the first electrode 2, and further
By moving the ink jet head 24 in parallel.
The emission of pixels was repeated to form a light emitting layer.

In the formed organic LED display, no short circuit occurs between the first electrode film 2 and the second electrode film 4 between the first electrode film 2 and the second electrode film 4, and light emission is not caused. Non-uniform light emission from the edge of the pixel portion due to non-uniform thickness of the layer and the charge transport layer was not observed. Further, by applying a pulse voltage of 30 V to this display, uniform light emission was obtained from all the pixels.

[0040]Example 3  First, a thin film transistor was formed on a glass substrate 1.
Thereafter, the first electrode film 2 has a long side of 500 μm and a short side of 500 μm.
An ITO transparent electrode was formed to have a thickness of 220 μm. This
, The critical surface tension γc of the ITO surface at 20 ° C.
Was 56 dyne / cm.

Next, a 30 μm-thick resist film was formed on the substrate 1 by spin coating using a positive resist having a critical surface tension γc at 20 ° C. of 20 dyne / cm. Next, the frame wall 5 was manufactured using an exposure mask. As the mask for exposure, as shown in FIG. 2C described above, the inside corner of the frame wall 5 had a shape of a corner 51c protruding toward the center. Then
Rinse off the resist residue and remove 5 in the direction parallel to the ITO.
40 μm pitch, 230 μm in the direction perpendicular to ITO
At the pitch, a frame wall 5 having a width of 40 μm was produced. Next, an organic material was formed in the same manner as in Example 2. Next, Al and Li
Is co-evaporated to form AlL as the second electrode film 4.
An i-alloy electrode was formed. Finally, sealing was performed using an epoxy resin.

The formed organic LED display has no short circuit between the first electrode film 2 and the second electrode film 4, between the first electrode film 2 and the second electrode film 4, and emits light. Non-uniform light emission from the edge of the pixel portion due to non-uniform thickness of the layer and the charge transport layer was not observed. Further, by applying a pulse voltage of 30 V to this display, uniform light emission was obtained from all the pixels.

[0043]

According to the present invention, the corner of the inside of the frame wall is filled with the organic material liquid when the organic material liquid is injected into the inside of the frame wall by taking the corner inside the frame wall. When the liquid solidifies, an organic layer having no gap is formed between the liquid and the corner inside the frame wall. Therefore, it is possible to prevent the second electrode film from entering the gap between the frame wall and the organic layer and causing a short circuit with the first electrode film.

By selecting both the organic material liquid and the frame wall material such that the critical surface tension of the frame wall is smaller than the surface tension of the organic material liquid injected into the inside of the frame wall, A convex meniscus is formed on the upper surface, and the organic material liquid is settled inside the frame wall without straddling adjacent pixels, so that the entire organic layer can emit light uniformly. Furthermore, by selecting both so that the critical surface tension of the first electrode film becomes larger than the surface tension of the organic material liquid, the organic material liquid can be filled up to the lower corner of the inner corner of the frame wall. . As a result, short circuits between pixels and between electrode films can be prevented while maintaining a high aperture ratio, and extremely vivid color display can be achieved.

Further, it is possible to suppress the color mixture due to the mixture of the organic layers, or the emission of the high-energy emission color due to the energy transfer occurring between the light-emitting materials due to the mixture of the organic layers, thereby preventing a remarkable decrease in display quality. Further, when the second electrode film is formed using the shadow mask, damage to the organic layer due to close contact of the shadow mask can be prevented. In this case, the second electrode film can be patterned without using a shadow mask by making the shape of the frame wall an appropriate shape, for example, a reverse taper shape.

Therefore, according to the manufacturing method of the present invention,
A short circuit between electrode films and between pixels can be prevented, and an organic light emitting device having excellent display quality and a high aperture ratio can be easily and inexpensively manufactured by a wet method.

[Brief description of the drawings]

FIG. 1 is an enlarged vertical sectional view of an organic LED display according to the present invention.

FIG. 2 is an organic L illustrating a shape of a corner inside a frame wall of FIG. 1;
FIG. 2 is a horizontal sectional view of the ED display.

FIG. 3 is a schematic partial plan view showing an arrangement example of a light emitting layer of the organic LED display according to the present invention.

FIG. 4 is a schematic partial plan view showing a configuration example of an electrode film of an organic LED display according to the present invention.

FIG. 5 is a schematic partial plan view corresponding to FIG. 4, showing another configuration example of the electrode film of the organic LED display according to the present invention.

FIG. 6 is a conceptual diagram illustrating an example of a method for forming an organic layer according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Substrate 2 1st electrode film 3 Organic layer 4 2nd electrode film 5 Frame wall 6 Sealing film 7 Deflection plate 10 Organic LED element (organic light emitting element) 11 Red light emitting pixel 12 Green light emitting pixel 13 Blue light emitting pixel 20 Organic LED display Reference Signs List 21 thin film transistor (TFT) 22 source bus line 23 gate bus line 24 inkjet head 51 corner

Claims (7)

[Claims] An organic device comprising a substrate, a first electrode, a frame wall surrounding four circumferences of each pixel, an organic layer formed on the electrode, and a second electrode formed on the organic layer. In the light emitting element, at least one of the organic layers is formed by solidifying a solution or dispersion containing an organic material injected into the inside of the frame wall, and the frame wall is formed of a solution or dispersion containing the injected organic material. An organic light emitting device, wherein the corners are cut off so that the corners inside the frame wall are filled with a liquid. 2. The short-circuit between the second electrode and the first electrode according to claim 1, wherein the organic layer closes the inside of the frame wall by filling the corner inside the corner wall of the corner. Organic light-emitting device. 3. First electrodes are vertically and horizontally arranged on a surface of a substrate,
An organic light-emitting device comprising: a step of forming at least one organic layer by injecting a solution or a dispersion containing an organic material onto the electrode film by surrounding four sides of each electrode film with a frame wall, and then forming a second electrode. The method for manufacturing an organic light-emitting element, wherein the inner corner of the frame wall is rounded so as to be filled with a solution or a dispersion containing an organic material. 4. The organic light emitting device according to claim 3, wherein the critical surface tension of the frame wall is smaller than the surface tension of a solution or a dispersion containing an organic material to be injected into the inside of the frame wall. Method. 5. The critical surface tension of the first electrode is higher than the surface tension of a solution or dispersion containing an organic material.
Or the method for manufacturing an organic light-emitting device according to 4. 6. When forming a frame wall, a resist film is formed on the surface of the substrate, and then the resist film is etched by using a photomask of the frame wall having a chamfered corner. 6. The method of claim 3, further comprising obtaining a trimmed frame wall.
The method for producing an organic light-emitting device according to any one of the above. 7. The organic layer according to claim 3, wherein the organic layer is formed from a solution or a dispersion containing an organic material by using an injection method selected from a spin coating method, an inkjet method, and a nozzle injection method. A method for manufacturing an organic light-emitting device according to any one of the above.