JP2003142261A - Manufacturing method of organic el display element, and organic el display element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method of a flat and uniform organic EL display element capable of forming a organic layer with corrected patterning error, prevented from the generation of leakage and uneven brightness. SOLUTION: For the manufacturing method of the organic EL display element comprising a positive electrode, a negative electrode and at least one layer of patterned organic layer laid between those electrodes, the organic layer is flattened and a patterning error is corrected after forming the patterned organic layer by coating a solvent capable of dissolving the organic layer on the organic layer by spray coating and redissolving the organic layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an organic EL display device and an organic EL display device, and more particularly, to a non-uniformity of an organic layer which occurs when a patterned organic layer is formed, and The present invention relates to a method for manufacturing an organic EL display element capable of correcting a patterning error, and an organic EL display element having a flat organic layer obtained by these corrections and having a suppressed patterning error.

[0002]

2. Description of the Related Art In recent years, stacked organic EL devices (Appl.Phys.Lett.51, P913 (1987)) using a vacuum evaporation method have been successively put into practical use and have been put into practical use. is there. On the other hand, the organic EL device by the coating method (Nature 347,5
39 (1990)) has also been actively developed, and has characteristics comparable to those of elements produced by vapor deposition.

By the way, when a colorization device is used by using an organic EL element, elements having different emission colors must be arranged on the same substrate. The organic EL element is a device using an organic material and is corroded by most organic solvents. Further, it is very sensitive to moisture, and destruction easily progresses due to moisture.
Therefore, it is difficult to pass through a process such as ordinary photolithography and it is difficult to pattern the organic layer.

However, in the laminated organic EL display by the vacuum vapor deposition method, each element can be arranged in a delicate pattern by vapor deposition through a metal mask, and the vapor deposition portion and the non-vapor deposition portion can be accurately formed by mask vapor deposition. It can be painted separately and has already been announced as a full color display.

On the other hand, there is currently no definitive method for colorizing an organic EL element using a coating method, which is disadvantageous to a vacuum evaporation system when forming a device. In order to solve this problem, various methods have been proposed, and as one of them, an inkjet method may be used, and a full-color display by the inkjet method has been proposed (JP-A-10-12377). , There are many issues for practical use. As such, first, there is a problem of variation in dot size due to uneven coating amount. Further, there is a problem of non-uniformity of the dot shape that the applied solution becomes a concave shape due to the influence of the surface tension. As a result, uneven brightness (uneven light emission) occurs in which the center is bright during light emission and darkens toward the outer circumference. In addition, there is a problem of ink landing accuracy due to flight bending, and the organic layer is formed at a position deviated from the target electrode, so that the electrodes are in direct contact with each other and a dot defect is likely to occur due to leakage. There is.

In an attempt to prevent a leakage current caused by such a problem of landing accuracy, a thin film layer for suppressing an unnecessary current that does not contribute to light emission is provided between the organic layer and the anode or the cathode by spin coating or the like. Although a method has been proposed (Japanese Unexamined Patent Publication No. 2000-100572), since this thin film layer has an insulating property and has a property that it is difficult to pass a current, problems such as a remarkable increase in drive voltage occur. Similarly, a method has also been proposed in which a bank made of a hydrophobic resin is provided around the ink landing position to control the ink landing point (Japanese Patent Laid-Open No. 2000-353594). By using this method, the landing position can be controlled to some extent, but leaks and uneven light emission cannot be completely suppressed, and further improvement is necessary.

On the other hand, patterning of an organic layer by a printing method such as gravure printing has been proposed, but a desired shape can be maintained at the time of printing due to problems of low viscosity of a coating solution itself of an organic EL material and thixotropy. There is a big problem that it does not exist. In addition, since the characteristics of the organic EL element are extremely deteriorated, there is a problem that it is difficult to add an additive or the like. The organic EL patterned finely by such a printing method.
At present, there are almost no reports of devices. Further, theoretically, it is possible to obtain an organic layer having a desired shape by heating the substrate at the time of printing and quickly evaporating the coating liquid, but an organic layer having a large unevenness is obtained. Is difficult.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to flatten an organic layer to form a uniform layer and to prevent patterning errors when the patterned organic layer is formed by a coating method, especially an ink jet method. It is an object of the present invention to provide an organic EL display element that is corrected and can prevent leaks, uneven brightness (uneven light emission), and the like, and can be patterned for practical use.

[0009]

The above object can be achieved by the present invention described below. (1) A method for producing an organic EL display device, which has an anode and a cathode, has at least one organic layer sandwiched between these electrodes, and which is patterned. After forming the patterned organic layer,
A method for manufacturing an organic EL display device, wherein a solvent in which the organic layer is soluble is applied to the organic layer by spray coating, the organic layer is redissolved, and the organic layer is planarized and patterning errors are corrected. (2) The method for producing an organic EL display device according to (1) above, wherein the patterned organic layer contains a polymer compound and the patterned organic layer is formed by a coating method. (3) The method for manufacturing an organic EL display element according to (2) above, wherein the patterned organic layer is formed by an inkjet method. (4) An organic EL display device having an anode and a cathode, further having at least one organic layer sandwiched between these electrodes, and the organic layer being patterned. After the organic layer is patterned and formed, a soluble solution is applied by spray coating and redissolved, and the organic layer is flat and a patterning error is corrected. Organic EL device.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.
The organic EL display element of the present invention has an anode and a cathode, and has at least one organic layer sandwiched between these electrodes, and the organic layer is patterned.

In manufacturing such an organic EL display device, in the present invention, after forming a patterned organic layer, a solvent in which the organic layer is soluble (soluble solvent) is applied by spray coating. . Therefore, the patterned organic layer once formed is redissolved by the solution and leveled. After that, if the solvent is removed by evaporating it, the organic layer is flattened and a uniform organic layer is obtained. Furthermore, since the organic layer is not formed at the target position, the electrodes contact each other and a leak occurs when the device is configured, but since it becomes possible to re-dissolve, the organic layer is expanded and the lower layer is formed. It is possible to completely cover the electrode. Therefore, it becomes possible to correct a patterning error that causes a leak.

The patterned organic layer is
It is preferable that it is formed by a coating method, and it is conceivable that patterning is performed after the organic layer is formed by coating, but in order to effectively obtain the effect of the present invention, patterning is performed together with the coating layer. Specifically, an inkjet method, a printing method such as gravure printing, and the like are specifically mentioned, and the inkjet method is particularly preferable.

In the case of the ink jet method, the applied solution has a concave shape due to the influence of the surface tension, and the shape is maintained even after drying. Due to the non-uniformity of this shape, the device is formed. During light emission, brightness unevenness (light emission unevenness) occurs in which the center is bright and becomes darker toward the outer periphery, but in the present invention, the soluble solvent is applied to the organic layer by spray coating to flatten the organic layer. This can be prevented, because it can be made uniform and uniformized. In addition, since the organic layer is formed at a position displaced from the electrode due to the displacement of the landing position of the ink, the electrodes are in direct contact with each other and a dot defect occurs due to leakage. Since the patterning position can be corrected so as to cover the lower electrode, the occurrence of leak can be prevented. As described above, what is important in the present invention is to obtain an organic layer having a size necessary for preventing the electrodes from contacting each other. Further, when attention is paid to the individual patterned organic layers, it is preferable that the individual organic layers have a uniform thickness and a uniform thickness and size in order to prevent uneven brightness.

The soluble solvent used in the redissolving treatment in the present invention is such that the organic layer to be redissolved is soluble.
Although not particularly limited, the boiling point is 100 to 15 since the solvent needs to be removed by evaporation or the like after the redissolving treatment.
About 0 ° C is preferable. Also, if the boiling point is too low,
Although the purpose of the re-dissolution treatment is not achieved, a low boiling point solvent (boiling point of about 30 to 100 ° C.) can be used as a mixture with a high boiling point solvent (boiling point of about 150 to 200 ° C.). When such a mixed solvent is used, the low boiling point solvent and the high boiling point solvent can be used in a volume ratio of 10:90 to 90:10.

The specific solvent can be selected depending on the constituent material of the organic layer, but generally, toluene, xylene and the like are listed as those having a boiling point in the above preferred range. These may be used alone or in combination of two or more. In addition, examples of the soluble low-boiling point solvent generally used include dichloromethane, chloroform, tetrahydrofuran (THF) and the like, and examples of the high-boiling point solvent which is preferably used in combination therewith include quinoline, decalin and the like. These may be a mixed solvent using only one kind of each solvent, or a mixed solvent of a combination using two or more kinds of at least one.

Solubility of organic layer in soluble solvent (25
C.) is preferably about 0.1 to 2% (mass percentage). Although the respective constituent materials of the organic layer have different solubilities, the above-mentioned solubilities are based on the entire organic layer.

The soluble solvent can be applied in a small amount using an easily soluble solvent having a relatively high solubility, or can be applied in a relatively large amount using a slightly soluble solvent having a low solubility. Thus, the coating amount can be controlled by the solubility of the organic layer. The coating amount of soluble solvent is
Usually, the organic layer 1 mm ² per 0.1Nl～1myueru (diameter 10
It can be selected from the range of about 1 pl to 10 nl per dot of about 0 nm.

In the present invention, the soluble solvent is applied by spray coating. By using such an application method, the organic layer or a part of the organic layer can be redissolved without losing the formed organic layer, The formation of a uniform organic layer is facilitated. The coating pressure can be adjusted within the range of 0.1 to 1 MPa,
It is not limited to this. As the spray coating device, a commercially available device can be used. For example, Nordson
A swirl spray coating device, a micro spray coating device or the like manufactured by Co., Ltd. can be used.

In the present invention, the formation of the patterned organic layer which is the object of the re-dissolution treatment is preferably carried out by an ink jet method. Regarding the ink jet method, for example, Japanese Patent Laid-Open No. 2000-353594, Shunichi Seki, Satoru Miyashita, Applied Physics, Volume 70, No. 1 (2)
001) and the like.

As a preferred example of the manufacturing process of the present invention,
First, an insulating layer bank that separates pixel regions is provided on a substrate on which an electrode pattern has been formed, and an inkjet method is used.
Specified size (usually 100 μm diameter) and specified thickness (50 to 2
An organic layer of about 00 nm) is formed. In this case, it is preferable that the organic layer has a size that covers the patterned electrode, and the thickness is about 1.5 to 2 times thicker than the final target thickness in consideration of the remelting treatment.

The insulating layer bank is formed of an insulating resin such as polyimide, but an insulating inorganic material or the like may be used, or an insulating multilayer bank in which a polyimide layer is formed on a SiO ₂ layer may be used. The height of the bank is about 1 to 2 μm, and a taper may be provided. Further, in order to prevent the ink from landing on the bank, it is also preferable to make only the polyimide layer surface ink-repellent by, for example, fluorinating, from the viewpoint of increasing the patterning accuracy and forming the organic layer at a predetermined position.

When the organic layer thus formed is subjected to the re-melting treatment, it is flattened to obtain an organic layer which is slightly larger than that before the re-melting treatment and has a reduced thickness.
In this way, for example, from a diameter of about 100 μm and a thickness of about 200 nm to a diameter of 140 to 15
An organic layer having a thickness of about 0 μm and a thickness of about 90 to 100 nm can be obtained. Then, an electrode pattern forming a pair with the above electrode is formed in an organic layer to obtain an element.

In the present invention, the organic material for forming the organic layer is a general term for a light emitting material and a charge transporting material (electron transporting material and hole transporting material) as generally used in organic EL devices. .) And the like can be used.

For example, a light emitting layer using a polymer light emitting material, a mixed light emitting layer of a polymer light emitting material and a charge transport material, or electron injection transport between such a light emitting layer and a cathode (electron injection electrode). It may have an electron injecting / transporting layer containing a conductive material, or may have a hole injecting / transporting layer containing a hole injecting / transporting material between the light emitting layer and the anode (hole injecting electrode). Further, instead of the electron injecting and transporting layer and the hole injecting and transporting layer, a high resistance electron injecting and transporting layer and a hole injecting and transporting layer made of an inorganic material may be provided.

In the present invention, the organic layer preferably contains a polymer compound in order to ensure the function as a wet type element. In the case of a polymer, the molecular weight of such a high molecular compound is 50 as expressed by the weight average molecular weight Mw.
00 or more, usually about 5000 to 3 million.

Specifically, it is mainly used as a light emitting material and a hole transporting material, and polyethylenedioxythiophene / polystyrene sulfonate (PEDO) is used.
T / PSS), polyvinyl carbazole (PVK), metal phthalocyanine compound, polyaniline / polystyrene sulfonate (Pani / PSS), polyparaphenylene vinylene derivative (PPV derivative) of the following formula (P-1), and the following formula (P Any of the polyarylfluorene derivatives of -2) or a mixture thereof can be mentioned.

[0027]

[Chemical 1]

(R is a 2-ethylhexyloxy group, R'is a methoxy group, n is the degree of polymerization, Mw
Is 50,000. )

[0029]

[Chemical 2]

(R ₁ and R ₁ 'are each an alkyl group, Ar is an optionally substituted aromatic ring group or heterocyclic group, n is the degree of polymerization, and Mw is 5000 to 3
It is, 000,000. )

The light emitting layer may be one layer or two or more layers, and a plurality of layers may be formed by the light emitting layer and the charge transport layer. Furthermore, the light emitting layer is, in addition to the polymer light emitting material,
The following light emitting material and charge transporting material may be contained. Further, the polymer light emitting material and / or the charge transport material may be dispersed in a polymer compound.

Known light-emitting materials that can be used with the polymeric light-emitting material of the present invention are not particularly limited.
Naphthalene derivatives, anthracene and its derivatives, perylene and its derivatives, polymethine-based, xanthene-based, coumarin-based, cyanine-based dyes, metal complexes of 8-hydroxyquinoline and its derivatives, aromatic amines, tetraphenylcyclopentadiene and its Derivatives, tetraphenyl butadiene and derivatives thereof and the like can be used. Specifically, for example, JP-A-57
Known ones such as those described in JP-A-51781 and JP-A-59-194393 can be used.

As the charge-transporting material that can be used in the present invention, various electron-transporting materials and hole-transporting materials can be used and are not particularly limited.

Examples of the hole transporting material include pyrazoline derivatives, arylamine derivatives, stilpene derivatives, triphenyldiamine derivatives and the like.

Examples of the electron transporting material include oxadiazole derivatives, anthraquinodimethane and its derivatives, benzoquinone and its derivatives, naphthoquinone and its derivatives, anthraquinone and its derivatives, tetracyanoanthraquinodimethane and its derivatives, fluorene and its derivatives. Examples thereof include metal complexes such as derivatives thereof, diphenyldicyanoethylene and derivatives thereof, diphenoquinone derivatives, 8-hydroxyquinoline and derivatives thereof and the like.

Specifically, JP-A-63-70257, JP-A-63-175860, and JP-A-2-1353.
No. 59, No. 2-135361, No. 2-209.
No. 988, No. 3-37992, and No. 3-152.
Examples thereof include those described in Japanese Patent No. 184.

Particularly, 4,4-bis (N- (3-methylphenyl) -N-phenylamino) biphenyl is used as the hole transporting material, and 2- (4-biphenylyl) -5- (4 is used as the electron transporting material. -T-butylphenyl) -1,
3,4-oxadiazole, benzoquinone, anthraquinone and tris (8-quinolinolato) aluminum are preferred.

Of these, either one of the electron transporting compound and the hole transporting compound, or both of them may be used at the same time. These may be used alone or in combination.

Since the amount of the charge transport material used varies depending on the kind of the compound used and the like, the optimum amount of the charge transport material may be determined within a range that does not impair sufficient film forming properties and light emission characteristics. Usually, it is 1 to 40% (mass percentage) with respect to the light emitting material, and more preferably 2 to 30% (mass percentage).

Further, the organic layer may have an electron injecting and transporting layer, a hole injecting and transporting layer and the like in addition to the above light emitting layer. The electron injecting and transporting layer composed of an organic material, the electron transporting material and the hole transporting material used in the hole injecting and transporting layer may be selected from the above materials, which are suitable in relation to the light emitting layer and the electrode.

The thickness of the light emitting layer when the above polymer light emitting material is used is 0.5 nm to 10 μm, preferably 1 nm to
It is 1 μm. In order to increase the current density and luminous efficiency, the range of 10 to 500 nm is preferable. In addition, when a thin film is formed by a coating method, in order to remove the solvent, it is desirable to heat and dry under reduced pressure or in an inert atmosphere at a temperature of 30 to 200 ° C., preferably 60 to 100 ° C.

When the charge injecting and transporting layer is formed below the light emitting layer, heat resistance is required to some extent when the heat polymerization step is required to form the light emitting layer. In this case, the glass transition temperature is preferably 100 ° C. or higher, more preferably 1
A compound having a temperature of 50 ° C or higher, particularly 200 ° C or higher is preferable. The upper limit of the glass transition temperature is not particularly limited, but is about 300 ° C.

The thickness of the organic hole injecting and transporting layer and the thickness of the electron injecting and transporting layer are not particularly limited and may vary depending on the forming method, but are usually about 5 to 500 nm, particularly 10 to 300 nm. Is preferred. When the hole injection layer and the transport layer are provided, it is preferable that the injection layer has a thickness of 1 nm or more and the transport layer has a thickness of 1 nm or more. Injection layer at this time,
The upper limit of the thickness of the transport layer is usually about 500 nm in the injection layer,
It is about 500 nm in the transport layer.

The solvent used for forming the organic layer of the present invention is not particularly limited as long as it dissolves the organic material and does not cause any trouble during coating. Specifically, those generally used such as alcohols, hydrocarbons, ketones and ethers can be used.
Of these, chloroform, methylene chloride, dichloroethane, tetrahydrofuran, toluene, xylene and the like are preferable. Although depending on the structure and molecular weight of the polymer material, usually 0.1% (mass percentage) or more can be dissolved in these solvents.

When the cathode (electron injection electrode) is used in combination with an electron injection layer such as an inorganic electron injection layer, it is not necessary to have an electron injection property with a low work function. It is not necessary to be limited, and a usual metal can be used. Among them, Al, Ag, In, Ti, Cu, Au, Mo, W,
Pt, Pd and Ni, particularly one or two metal elements selected from Al and Ag are preferable. The thickness of these cathodes may be a certain thickness or more capable of giving electrons to the high resistance inorganic electron injecting and transporting layer, and 50 nm or more,
The thickness is preferably 100 nm or more. The upper limit is not particularly limited, but usually the thickness is 50 to 500 nm.
It should be about.

If necessary, the following may be used as the cathode (electron injecting electrode). For example, K, Cs,
Li, Na, Mg, La, Ce, Ca, Sr, Ba, S
n, Zn, Zr, and other metallic elements alone, or a two-component, three-component alloy system containing them for improving stability, for example, Ag / Mg alloy (Ag amount 0.1 to 50% (atomic ratio)) , Al.Li alloy (Li content 0.01 to 14% (atomic ratio)), In.Mg alloy (Mg: 50 to 80% (atomic ratio)), Al.Ca alloy (Ca amount 0.01 to 20%) (Atomic ratio)) and the like. The thickness of the cathode (electron injection electrode) may be a certain thickness or more that can sufficiently inject electrons, and is 0.1 nm or more, preferably 0.5 nm or more, and particularly 1 nm.
The above is sufficient. The upper limit is not particularly limited, but the thickness is usually about 1 to 500 nm. An auxiliary electrode (protective electrode) may be further provided on the cathode (electron injection electrode).

The thickness of the auxiliary electrode may be a certain thickness or more, preferably 50 nm or more, more preferably 100 nm or more, particularly in order to secure the electron injection efficiency and prevent the invasion of water, oxygen or an organic solvent. The range from 100 to 500 nm is preferred. If the auxiliary electrode layer is too thin, the effect cannot be obtained, and the step coverage of the auxiliary electrode layer becomes low, resulting in insufficient connection with the terminal electrode. On the other hand, if the auxiliary electrode layer is too thick, the stress of the auxiliary electrode layer becomes large, which causes a problem such as an increase in the growth rate of dark spots. For the auxiliary electrode, an optimum material may be selected and used depending on the material of the electron injection electrode to be combined. For example, if importance is attached to ensuring the electron injection efficiency, a low resistance metal such as Al may be used, and if importance is attached to the sealing property, a metal compound such as TiN may be used.

The total thickness of the cathode (electron injection electrode) and the auxiliary electrode is not particularly limited, but usually 50 to 50.
It may be about 500 nm.

The material of the anode (hole injecting electrode) is an inorganic material.
To the hole injection transport layer or the organic hole injection transport layer.
It is preferable to use one that can be efficiently injected.
Substances with a function of 4.5 eV to 5.5 eV are preferred. Specifically
Is tin-doped indium oxide (ITO), zinc-doped acid
Indium oxide (IZO), indium oxide (In
₂O₃ ), Tin oxide (SnO)₂) And zinc oxide (Zn
It is preferable that any one of O) is the main composition. these
Oxides may be slightly deviated from their stoichiometric composition
Yes. In₂O₃Against SnO₂The mixing ratio of 1 to 20
% (Mass percentage), and further 5 to 12% (mass percentage)
Is preferred. In addition, in InZO₂O₃Against Zn
The mixing ratio of O is usually about 12 to 32% (mass percentage).
Is.

The work function of the anode (hole injection electrode) is adjusted.
Silicon oxide (SiO ₂) Is included
Good. Silicon oxide (SiO₂) Content is ITO
Against SiO₂A molar ratio of 0.5-10% is preferable.
Good SiO₂The work of ITO by containing
The function increases.

The electrode on the side from which light is extracted is the emission wavelength band,
It is preferable that the light transmittance is usually 400 to 700 nm, especially 50% or more, further 80% or more, and particularly 90% or more for each emitted light. If the transmittance is too low, the light emission itself from the light emitting layer is attenuated, and it becomes difficult to obtain the brightness required for the light emitting element. In that case, the thickness of the electrode is 50
The range from ˜500 nm, especially from 50 to 300 nm is preferred. Further, the upper limit is not particularly limited, but if it is too thick, there is a concern that the transmittance may decrease or peeling may occur. If the thickness is too thin,
A sufficient effect cannot be obtained, and there is a problem in film strength and the like during manufacturing. Such electrodes are often anodes.

Further, in order to prevent deterioration of the organic layers and electrodes of the element, it is preferable to seal the element with a sealing plate or the like. The sealing plate adheres and seals the sealing plate using an adhesive resin layer in order to prevent the infiltration of moisture. The sealing gas is A
Inert gases such as r, He and N ₂ are preferable. The water content of the sealing gas is preferably 100 ppm or less, more preferably 10 ppm or less, and particularly preferably 1 ppm or less. There is no particular lower limit to this water content, but it is usually about 0.1 ppm.

In the present invention, the substrate on which the organic EL structure is formed is an amorphous substrate (eg, glass, quartz, etc.), a crystalline substrate (eg, Si, GaAs, ZnSe, etc.).
ZnS, GaP, InP and the like), and a substrate in which a crystalline, amorphous or metal buffer layer is formed on these crystalline substrates can also be used. As the metal substrate, Mo, Al, Pt, Ir, Au, Pd or the like can be used, and a glass substrate is preferably used. When the substrate is on the light extraction side, it is preferable that it has the same light transmittance as that of the electrode.

Further, a large number of the elements of the present invention may be arranged on a plane. The color of light emitted from each element arranged on a plane can be changed to provide a color display.

The substrate may be provided with a color filter film, a color conversion film containing a fluorescent substance, or a dielectric reflection film to control the emission color.

The organic EL display element of the present invention is usually used as a DC drive type or pulse drive type EL element.
It can also be AC driven. The applied voltage is usually 2 to
It is about 30V.

The organic EL display device of the present invention may have a structure in which, for example, the substrate / first electrode (anode) / organic layer (light emitting layer) / second electrode (cathode) is sequentially laminated. ,
A reverse laminated structure may be adopted. The laminated structure is, for example,
The optimal one may be appropriately determined according to the specifications of the display, the manufacturing process, and the like.

The organic EL display device of the present invention has various optical applications such as an optical pickup used for memory reading / writing, a relay device in a transmission line of optical communication, a photocoupler, etc., in addition to the application as a display. It can be used for devices.

[0059]

EXAMPLES The present invention will be specifically described below with reference to examples. A comparative example is also shown.

Example 1 As a substrate, a glass substrate (Corning 7059,
1.1 mm thick), as shown in FIG.
A bank 3 (height 2 μm) made of polyimide and having a taper was provided on the ITO 2. On this substrate, ITO (150 nm thick) with a diameter of 80 μm was used as the ink impact point.
Is exposed in a straight line. The substrate was ultrasonically cleaned using an alkaline detergent, rinsed twice with distilled water, and then washed with ethanol and acetone similarly using ultrasonic waves. Coating was attempted on the ITO of this substrate by an inkjet method, and the ratio of leak and the unevenness of light emission were observed.

The coating ink is polyvinyl carbazole (hereinafter PVK), and the electron transport material 2- (4-biphenylyl) -5- (4-t-butylphenyl) -1-.
A ratio (mass ratio) of 3,4-oxadiazole (tBuPBD) and a doping material Ir (ppy) ₃ complex (ppy represents phenylpyridine) of 70: 30: 1.
What was mixed with and dissolved in toluene at a concentration of 1% (mass percentage) was used. The ink having this concentration was applied by an inkjet printer to form an organic layer having a thickness of 200 nm. The coating state of the organic layer 4 in this case is, for example, as shown in FIG.
It becomes like (b). The desired layer thickness is about 100 nm, but in consideration of dissolution and leveling by spray coating (the layer thickness becomes thin), the coating was purposely made to be a layer thickness thicker than usual. Coating was performed by an inkjet printer under such conditions. The diameter of the organic layer 4 after coating is 100 μm, which is theoretically sufficient to cover the ITO having a diameter of 80 μm. In addition, the thickness of the organic layer 4 in this case is obtained by obtaining an average value for each organic layer and further obtaining an average value for the whole. The diameter was the average of the maximum diameters.

Then, re-dissolution treatment by spray coating was performed. As a result, the coating state of the organic layer 4 becomes as shown in FIG. The solvent is toluene and the coating pressure is 0.
The spray gun moving speed was 3 cm / sec, and the distance between the spray gun and the substrate was 10 cm. Coating amount is 1mm for organic layer
^{It was set to 10} nl per ² . After natural drying, the organic layer 4 had a diameter of 150 μm and a thickness of 100 nm. Moreover, when the individual organic layers 4 were observed, there was little variation and they were uniform. The diameter was the average value of the maximum diameters (the maximum distance between the banks 3 in which the organic layer 4 is in contact with the banks 3), and the thickness was the value obtained by further averaging the individual average values.

Next, the substrate was moved to a vacuum vapor deposition apparatus, and Cs of 2 nm thickness and Al of 250 nm thickness were successively formed as cathodes to form organic EL display elements.

This device was made to emit light at 15V. The emission color was green. Although coating unevenness was observed in the peripheral portion of the coating film itself, since the diameter was sufficiently larger than that of ITO, such uneven light emission due to coating unevenness was hardly observed. In addition, due to re-dissolution and leveling of the organic layer, the leak occurrence rate under this condition was 12%.

Example 2 The same operation as in Example 1 was carried out except that the polyimide bank of Example 1 was subjected to a water repellent treatment with trifluoromethane. Even in this device, uneven light emission was hardly observed, and the leak occurrence rate was reduced to 2%.

Comparative Example 1 The same operation as in Example 1 was carried out except that the redissolution treatment by spray coating was not carried out and the ink concentration was 0.5% (mass percentage). The ink having this concentration was applied by an inkjet printer to form an organic layer having a thickness of 100 nm. In this element, the leak occurrence rate reached 38%, which was higher than that in Example 1. In addition, in the element emitting light, uneven light emission was observed around the ITO.

Comparative Example 2 The same operation as in Comparative Example 1 was performed using the same water-repellent treated substrate as in Example 2. Although the leak occurrence rate fell to 14%, the occurrence rate was higher than that when spray coating was applied. Further, the same light emission unevenness as in Comparative Example 1 was observed.

[0068]

EFFECTS OF THE INVENTION According to the present invention, an organic layer which is flat and uniform and has a corrected patterning error is obtained, and the organic EL display device having the patterned organic layer is used. It is possible to prevent the occurrence of uneven brightness.

[Brief description of drawings]

FIG. 1 is a diagram showing a process of forming an organic layer in an example, (a) is a schematic cross-sectional view of a substrate provided with a bank to be used, and (b) is a schematic diagram after an organic layer is formed by an inkjet method. A sectional view, (c) is a schematic sectional view after spray coating.

[Explanation of symbols]

1 substrate 2 ITO 3 banks 4 organic layers

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H05B 33/14 H05B 33/14 A 33/22 33/22 Z F term (reference) 3K007 AB17 AB18 BA06 CB01 DB03 FA01 4D075 AA01 AA82 AC07 AE03 AE12 BB60Z DB53 DC24 EA05 EB31 EC30 5C094 AA03 AA31 AA42 AA43 BA27 DA13 EA05 FA01 FA02 FB01 FB20 5G435 AA01 AA14 AA17 BB05 HH01 HH20 KK05

Claims (4)

[Claims] 1. A method of manufacturing an organic EL display device, comprising an anode and a cathode, at least one organic layer sandwiched between these electrodes, and the organic layer being patterned. Then, after forming the patterned organic layer, a solvent in which the organic layer is soluble is applied to the organic layer by spray coating, the organic layer is redissolved, and the planarization and patterning error of the organic layer is caused. Organic EL that corrects
Display element manufacturing method. 2. The method for producing an organic EL display device according to claim 1, wherein the patterned organic layer contains a polymer compound, and the patterned organic layer is formed by a coating method. 3. The method for manufacturing an organic EL display device according to claim 2, wherein the patterned organic layer is formed by an inkjet method. 4. An organic EL display device having an anode and a cathode, further comprising at least one organic layer sandwiched between these electrodes, and the organic layer being patterned. After the organic layer is patterned and formed, a soluble solution is applied by spray coating and redissolved, and the organic layer is flat and patterning errors are corrected. Organic EL device.