WO2012172919A1 - Method for manufacturing organic electroluminescent element - Google Patents

Abstract

Provided is a method for manufacturing an organic electroluminescent element, which has high production efficiency (high productivity and low equipment cost) and is capable of providing an organic electroluminescent element that has excellent quantum efficiency, emission life and resistance to luminance unevenness. This method for manufacturing an organic electroluminescent element is characterized in that an organic electroluminescent film is formed by continuously coating and laminating at least two organic functional layers on a sheet-like substrate by a die-coating method in an in-line system.

Description

Method for manufacturing organic electroluminescence device

The present invention relates to a method for producing an organic electroluminescence device capable of obtaining a high-quality organic functional film with a uniform film thickness, and having high productivity while keeping facility costs low.

Conventionally, an organic electroluminescence element (hereinafter also referred to as organic EL) is manufactured by a film forming method using a vapor deposition method, but in recent years, a wet coating method has been applied in order to improve productivity and reduce manufacturing costs. Development of a manufacturing method that has been developed is desired. In addition, when each constituent layer of the organic electroluminescence element is formed by a wet coating method, the viscosity of the coating solution used for forming each constituent layer is very low and the coating thickness is very thin. There is a strong demand for the formation of a layer having it.

A spin coating method is known as one of the coating methods applied to thin layer formation. The spin coating method is a method of forming a thin film by dropping a coating solution for forming a thin film on a substrate, and then rotating the support and coating the entire surface of the support by centrifugal force. The film thickness is controlled by the viscosity of the coating solution. The spin coating method includes, for example, formation of an interlayer insulating film such as a photoresist film or SOG (spin-on-glass) used in a semiconductor manufacturing process, formation of an overcoat film (flat film) or alignment film in a liquid crystal device manufacturing process, Is widely used for forming a protective film in a manufacturing process of an optical disk or the like.

However, although the spin coating method has high film thickness accuracy, it is necessary to rotate the support, and thus cannot be continuously applied to the belt-like support. For this reason, it is necessary to apply while replacing the cut support every time, and there is a problem that the amount of the coating liquid protruding from the end of the support is large at the time of application, and the production cost is increased.

Also, as another thin film coating method, an ink jet method is also known, but the ink jet method has a problem that the coating speed is slow and the productivity is low.

On the other hand, the flexographic printing method is known as a method capable of continuous production and effective for high-speed coating. However, the coating film of a display material used for a display device such as a liquid crystal device or an organic EL device has a high required film thickness accuracy, and a coating film prepared by a flexographic printing method has a required film thickness accuracy and coating quality. There is a problem that it cannot be obtained.

For this reason, in order to suppress coating unevenness in the flexographic printing method, there is a coating method in which the coating liquid filled in the concave portions of the plate material is transferred to the support using a plate material with unevenness uniformly provided on the entire surface of the plate material. Although described in Patent Document 1, it is not sufficient to satisfy the film thickness accuracy and the coating quality required for the coating film of the display material.

Furthermore, an extrusion coating method using a slit type die coater is also being studied because it can cope with high coating accuracy, high speed, thin film, suitability for multilayer coating, etc. For example, a method of continuous coating by a roll-to-roll method Is described in Patent Document 2. However, the roll-to-roll method is high in productivity, but the production line equipment is complicated and the investment cost is enormous. Therefore, it is possible to obtain a coating film with a uniform film thickness, and even with high productivity. Therefore, there has been a demand for a manufacturing method that can keep equipment costs low.

On the other hand, belt conveyors, roller conveyors and the like are generally widely used as conveying means for large and single-wafer substrates, but the substrate is damaged due to contact between the substrate and the conveying means during conveyance or transfer in the production line, Further, it has been found that fine fine powder due to contact adheres to the surface of the substrate to form a dark spot and a coating streak is generated by vibration. Therefore, although the method of conveying while floating by the air pressure blown from the porous plate is described in, for example, Patent Document 3, it is difficult to say that the effect is sufficient.

JP-A-9-131959 JP 2007-98224 A JP 2004-182378 A

The present invention has been made in view of the above-described problems, and an object thereof is to obtain an organic electroluminescence device having high production efficiency (high productivity, low equipment cost) and excellent quantum efficiency, light emission lifetime, and luminance unevenness resistance. Another object of the present invention is to provide a method for producing an organic electroluminescence device.
Furthermore, an object of the present invention is to provide a method for producing an organic electroluminescence device capable of obtaining a high-quality organic functional film having high productivity, high uniformity of a coating film, and reduced coating failure such as dark spots. Is to provide.

The above object of the present invention is achieved by the following configuration.

1. A method for producing an organic electroluminescent element, comprising forming an organic electroluminescent film by continuously laminating and coating at least two organic functional layers on a single wafer substrate by an in-line method by a die coating method.

2. After the organic functional layer of at least two layers is continuously laminated and applied in the first atmosphere (area 1) in which the volume concentration of the gas excluding the inert gas is 500 ppm or more, the volume concentration of the gas excluding the inert gas is 2. The method for producing an organic electroluminescent element according to 1 above, wherein the heat drying treatment is performed in a second atmosphere (area 2) of 200 ppm or less.

3. 3. The method for producing an organic electroluminescent element according to 1 or 2, wherein the at least two organic functional layers are laminated and applied at a coating speed of 5 m / min or more.

4. 4. The method for manufacturing an organic electroluminescent element according to 2 or 3, wherein the inert gas constituting the first atmosphere (area 1) and the second atmosphere (area 2) is nitrogen gas.

5. 5. The gas according to any one of 2 to 4, wherein the gas excluding the inert gas constituting the first atmosphere (area 1) and the second atmosphere (area 2) is moisture and oxygen gas. The manufacturing method of the organic electroluminescent element of description.

6. 6. The method of manufacturing an organic electroluminescence element according to any one of 1 to 5, wherein the single wafer substrate is a glass substrate.

7. A method for producing an organic electroluminescent element, wherein an organic functional layer laminate is formed by continuously laminating and applying at least two organic functional layers on a single wafer form substrate in an in-line manner using a die coater, comprising: The substrate levitation unit has a gas blowing portion and a gas suction portion, and controls the gas blowing amount and the suction amount to float the substrate while floating the substrate. A method for producing an organic electroluminescent element, characterized in that an organic functional layer laminate is formed by coating with an organic material.

8. 8. The method for producing an organic electroluminescent element according to 7, wherein one organic functional layer is applied on the single-wafer-shaped substrate, and each has an independent drying zone.

9. 9. The organic according to 7 or 8, wherein the first atmosphere (area 1) for applying the at least two organic functional layers is an atmosphere having a volume concentration of a gas excluding an inert gas of 500 ppm or more. Manufacturing method of electroluminescent element.

10. 10. The organic electro according to any one of 7 to 9, wherein the levitation gas supplied from the blowing unit of the substrate levitation unit is a gas having a volume concentration of a gas excluding inert gas of 500 ppm or more. Manufacturing method of luminescence element.

11. The organic functional layer laminate in which the at least two organic functional layers are continuously applied by in-line coating using a die coater is heat-dried in a second atmosphere (area 2) in which the volume concentration of gas excluding inert gas is 200 ppm or less. 11. The method for producing an organic electroluminescent element according to any one of 7 to 10, wherein:

12. The first atmosphere (area 1), the levitation gas supplied from the blowing unit of the substrate levitation unit, and the inert gas constituting the second atmosphere (area 2) are nitrogen gas. The manufacturing method of the organic electroluminescent element of any one of 1-11.

13. The gas excluding the first atmosphere (area 1), the floating gas supplied from the blowing unit of the substrate floating unit and the inert gas constituting the second atmosphere (area 2) is moisture and oxygen gas. 13. The method for producing an organic electroluminescence element according to any one of 9 to 12, which is characterized in that

14. 14. The method of manufacturing an organic electroluminescence element according to any one of 7 to 13, wherein the organic functional layer formed on the single wafer substrate is in a pattern shape.

15. An alignment mark is provided on the single wafer substrate, the alignment mark is detected, and supply and stop of the organic functional layer forming coating liquid from the die coater to the single wafer substrate is controlled. The manufacturing method of the organic electroluminescent element of any one of said 7 to 14 said.

16. 16. The manufacturing of an organic electroluminescence device according to any one of 7 to 15, wherein a wiping cleaning process is performed on the lip portion of the die coater when the coating liquid for forming the organic functional layer on the die coater is stopped. Method.

17. 17. The method for manufacturing an organic electroluminescent element according to any one of 7 to 16, wherein the single wafer substrate is a glass substrate.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide a method for producing an organic electroluminescence device that can provide an organic electroluminescence device that has high production efficiency (high productivity, low equipment cost), and excellent quantum efficiency, light emission lifetime, and luminance unevenness resistance. It was.

In the present invention, the substrate is further held by the substrate floating unit, and the substrate floating unit has a gas blowing portion and a gas suction portion, and controls the gas blowing amount and the suction amount to float the substrate. High-quality organic functions with high productivity, high coating uniformity, and reduced coating failures such as dark spots, etc. The manufacturing method of the organic electroluminescent element which can obtain a film | membrane could be provided.

It is sectional drawing which shows an example of the schematic structure of the organic EL element which concerns on this invention. It is a process flowchart which shows an example of the manufacturing process applicable to the manufacturing method of the organic EL element of this invention. It is a schematic sectional drawing which shows an example of the die-coater applicable to the manufacturing method of the organic EL element of this invention. It is a process flowchart which shows another example of the manufacturing process applicable to the manufacturing method of the organic EL element of this invention. It is a process flowchart which shows another example of the manufacturing process applicable to the manufacturing method of the organic EL element of this invention. It is a schematic sectional drawing which shows another example of the die-coater applicable to the manufacturing method of the organic EL element of this invention. It is the schematic which shows an example of a structure of the substrate floating unit applicable to the manufacturing method of the organic EL element of this invention. It is the schematic which shows another example of a structure of the board | substrate floating unit applicable to the manufacturing method of the organic EL element of this invention. It is the schematic which shows the arrangement | positioning of the detection of the alignment applicable to the manufacturing method of the organic EL element of this invention, and the wiping washing | cleaning apparatus of a die-coater. It is a schematic perspective view which shows an example of the main structures of the wiping washing | cleaning apparatus of the die-coater applicable to the manufacturing method of the organic EL element of this invention. It is a schematic diagram which shows an example of the manufacturing line which forms an organic functional layer by the batch system which is a comparative example used in the Example. It is a schematic diagram which shows an example of the manufacturing line which forms an organic functional layer by the roll-to-roll system which is a comparative example used in the Example.

Hereinafter, embodiments for carrying out the present invention will be described in detail.

As a result of intensive studies in view of the above problems, the present inventor has formed an organic electroluminescence film by continuously laminating and coating at least two organic functional layers on a single wafer substrate by an in-line method using a die coating method. The organic electroluminescence device having a high production efficiency (high productivity, low equipment cost), excellent quantum efficiency, light emission lifetime, and luminance unevenness resistance can be obtained by the organic electroluminescence device manufacturing method characterized by It has been found that a method for manufacturing a luminescence element can be realized, and has reached the present invention.

The present inventor also manufactures an organic electroluminescent device in which an organic functional layer laminate is formed by continuously laminating and coating at least two organic functional layers on a single wafer substrate in an in-line manner using a die coater. The substrate is held by a substrate floating unit, and the substrate floating unit includes a gas blowing unit and a gas suction unit, and controls the gas blowing amount and the suction amount, The organic electroluminescent device manufacturing method is characterized in that the organic functional layer laminate is formed by coating with the die coater while the substrate is levitated. The present inventors have found that a method for producing an organic electroluminescence element capable of obtaining a high-quality organic functional film with reduced coating failures such as the above can be realized.

Hereinafter, the details of the method for producing the organic electroluminescence element of the present invention will be described.

<< Basic structure of organic EL element >>
FIG. 1 shows an example of a basic configuration of an organic EL element according to the present invention.

In FIG. 1, the organic EL element 1 has a support substrate P. An anode 2 is formed on the support substrate P, an organic functional layer group 20 composed of a plurality of organic functional layers is formed on the anode 2, and a cathode 8 is formed on the organic functional layer group 20. Yes.

The organic functional layer group 20 includes organic functional layers constituting the organic EL element 1 provided between the anode 2 and the cathode 8.

The organic functional layers constituting the organic functional layer group 20 include, for example, a hole injection layer 3, a hole transport layer 4, a light emitting layer 5, an electron transport layer 6, and an electron injection layer 7, and in addition to holes A block layer, an electronic block layer, etc. may be included.

The anode 2, the organic functional layer 20, and the cathode 8 on the support substrate P are sealed with a flexible sealing member 10 via a sealing adhesive 9.

In addition, these layer structures (refer FIG. 1) of the organic EL element 1 show the preferable specific example, and this invention is not limited to these.

For example, the configuration of the organic EL element 1 according to the present invention may have the following layer structures (i) to (viii).

(I) Support substrate / anode / light emitting layer / electron transport layer / cathode / thermal conductive layer / sealing adhesive / sealing member (ii) Support substrate / anode / hole transport layer / light emitting layer / electron transport layer / Cathode / thermal conductive layer / adhesive for sealing / sealing member (iii) support substrate / anode / hole transport layer / light emitting layer / hole block layer / electron transport layer / cathode / heat conductive layer / adhesive for sealing Agent / Sealing Member (iv) Support Substrate / Anode / Hole Transport Layer / Light Emitting Layer / Hole Block Layer / Electron Transport Layer / Cathode Buffer Layer / Cathode / Heat Conductive Layer / Sealing Adhesive / Sealing Member ( v) Support substrate / anode / anode buffer layer / hole transport layer / light emitting layer / hole block layer / electron transport layer / cathode buffer layer / cathode / thermal conductive layer / sealing adhesive / sealing member As a substitute for the support substrate, a glass support may be used.

(Vi) Glass support / anode / hole injection layer / light emitting layer / electron injection layer / cathode / sealing member (vii) Glass support / anode / hole injection layer / hole transport layer / light emitting layer / electron injection Layer / cathode / sealing member (viii) glass support / anode / hole injection layer / hole transport layer / light emitting layer / electron transport layer / electron injection layer / cathode / sealing member << Method for Producing Organic EL Element >>
Next, details of the method for producing the organic EL device of the present invention will be described with reference to the drawings.

In the method for producing an organic EL device of the present invention, an organic functional layer is formed by continuously laminating at least two organic functional layers on a single-wafer substrate by an in-line method using a die coating method and using a wet coating liquid. It is characterized by forming a group.

FIG. 2 is a process flow chart showing an example of a manufacturing process applicable to the method for manufacturing an organic EL element of the present invention, and the organic EL element according to the present invention can be manufactured according to the flow shown in FIG.

As shown in FIG. 2, on a substrate holding member (substrate holding belt) 32 moving in the direction of the arrow, single-wafer-shaped substrates P cut to a desired size are arranged at regular intervals. In Stage 1, which is the first coating process, for example, in the organic EL element having the configuration shown in FIG. 1, the first organic functional layer L1 is formed on the substrate P formed up to the anode 2 using the first die coater Co1. For example, the hole injection layer 3 shown in the configuration of FIG. 1 is formed by a wet coating method by a die coating method. The 1st organic functional layer L1 (for example, hole injection layer 3) formed on the board | substrate P is transferred to the right side of a paper surface, and an organic solvent etc. are removed in the drying part H1 as needed. Next, the substrate P is transferred to Stage 2 which is the second coating process. In Stage 2, on the substrate P on which the first organic functional layer L1 is formed, the second die coater Co2 is used, and for example, the hole transport layer 4 shown in the configuration of FIG. It is formed by a wet coating method using a die coating method. The 2nd organic functional layer L2 (for example, hole transport layer 4) formed on the board | substrate P is transferred to the right side of a paper surface, and is dried in the drying part H2 as needed.

Similarly, the third organic functional layer L3 (for example, the light emitting layer 5) is prepared in Stage 3 as the third coating process, and the fourth organic functional layer L4 (for example, electron transport is performed in Stage 4 as the fourth coating process). The layer 6) is formed on the single wafer substrate P online.

Next, the single-wafer substrate P on which the organic functional layer group 20 is formed is transferred offline to the area 2 (40) having different atmospheric conditions, and finally dried by heat treatment (baking treatment) under specific atmospheric conditions. I do.

Next, the single-wafer substrate P on which the organic functional layer group 20 that has been subjected to the drying process is formed is transferred into a vapor deposition step 50, for example, a vacuum vapor deposition apparatus 51, and a desired constituent material is vapor deposited from a vapor deposition source 52. Then, the electron injection layer 7 and the cathode 8 are formed.

After forming the cathode 8, it is sealed with a flexible sealing member 10 via a sealing adhesive 9 in a sealing step, and an organic EL element is manufactured.

In the manufacturing flow of the series of organic EL elements described above, the second film forming environment 40 (area 2) is not performed without drying in the drying sections H1 to H4 in the first film forming environment 30 (area 1, Stages 1 to 4). ) May be collectively dried.

FIG. 4 is a process flow diagram showing an example of a manufacturing process provided with a substrate floating unit as another example of the manufacturing method applicable to the method of manufacturing the organic EL element of the present invention. According to the flow shown in FIG. The organic EL device according to the invention can be manufactured. In FIG. 4, the same reference numerals are given to components common to FIG. 2.

As shown in FIG. 4, in area 1 (30), on the substrate holding member 32 having gas permeability with a porous structure that is held by the support roll 54 and is moved in the direction of the arrow by the transfer roll 53, Single-wafer-shaped substrates P cut to a desired size are arranged at regular intervals. In Stage 1, which is the first coating process, for example, in the organic EL element having the configuration shown in FIG. 1, the first organic functional layer L1 is formed on the substrate P formed up to the anode 2 using the first die coater Co1. For example, the hole injection layer 3 shown in the configuration of FIG. 1 is formed by a wet coating method by a die coating method. The first organic functional layer L1 (for example, the hole injection layer 3) formed on the substrate P is transferred to the downstream side, and the organic solvent or the like is removed in the drying unit H1 of the drying zone D1 as necessary. Done. Next, the substrate P is transferred to Stage 2 which is the second coating process. In Stage 2, on the substrate P on which the first organic functional layer L1 is formed, the second die coater Co2 is used, and for example, the hole transport layer 4 shown in the configuration of FIG. It is formed by a wet coating method using a die coating method. The second organic functional layer L2 (for example, the hole transport layer 4) formed on the substrate P is further transferred to the downstream side, and is dried in the drying unit H2 of the drying zone D2 as necessary.

Similarly, the third organic functional layer L3 (for example, the light emitting layer 5) is prepared in Stage 3 as the third coating process, and the fourth organic functional layer L4 (for example, electron transport is performed in Stage 4 as the fourth coating process). The layer 6) is formed on the single wafer substrate P online.

Next, the single-wafer substrate P on which the organic functional layer group 20 is formed is transferred offline to the area 2 (40) having different atmospheric conditions, and finally dried by heat treatment (baking treatment) under specific atmospheric conditions. I do.

Next, the single-wafer substrate P on which the organic functional layer group 20 that has been subjected to the drying process is formed is transferred into a vapor deposition step 50, for example, a vacuum vapor deposition apparatus 51, and a desired constituent material is vapor deposited from a vapor deposition source 52. Then, the electron injection layer 7 and the cathode 8 are formed.

After forming the cathode 8, it is sealed with a flexible sealing member 10 via a sealing adhesive 9 in a sealing step, and an organic EL element is manufactured.

In the organic EL element production line as described above, in each stage coating step (position where the die coater is disposed), the substrate holding member 32 having a porous structure being transported and having a gas permeability is provided on the back surface portion. When the substrate floating portion 55 is disposed and coating is performed by a die coater, a compressed gas for floating the substrate is supplied from a porous substrate floating unit 56 (described in detail later) installed in the substrate floating portion 55. A method of carrying out suction by a blower and a vacuum pump, controlling the substrate to be controlled at a constant height, and carrying the substrate that has been levitated by suction by the suction unit in synchronization with the transport of the substrate holding member 32 It is.

Although there is no restriction | limiting in particular as a structure of the board | substrate holding member 32 applicable to this invention, It is a structure which can blow the compressed gas for board | substrate levitation from the board | substrate levitation unit 56 arrange | positioned in the back side stably to a board | substrate. Preferably, for example, a porous structure having a void structure penetrating in the film thickness direction, or a plurality of pores penetrating in the thickness direction at regular intervals on the surface of the substrate holding member 32 are provided. A punch plate structure may be used. In addition, even if the arrangement of the pores is a method perpendicular to the thickness direction, or in consideration of the transportability of the substrate to be levitated, the slant structure, for example, the substrate holding member 32 shown in FIG. It is preferable that the hole is inclined to the right side.

When the substrate P is transported in a state of being fixed to the substrate holding member 32, the distance between the bottom surface of the fixed die coater and the surface of the substrate P is affected by the displacement caused by vibration or the like during the transport of the substrate holding member 32. As a result, there is a possibility that liquid breakage may occur due to an excessively wide bead gap, which causes an uncoated portion. Further, the bead gap becomes excessively narrow, which causes a coating stripe. In addition, contact between the substrate holding member 32 and the substrate P during transportation may damage the edge portion of the substrate P, and may cause coating failure due to adhesion of generated dust or the like.

In order to solve the above problem, in the method for manufacturing an organic EL element of the present invention, the substrate P is applied to the substrate holding member 32 in a floating state, whereby the distance between the bottom surface of the die coater and the surface of the substrate P (bead). By strictly controlling the gap (also referred to as a gap) within a certain range, it is possible to prevent the occurrence of liquid breakage and application streaks during application, and also the generation of dust and the like by non-contact conveyance.

FIG. 5 is a process flow diagram showing an example of a substrate floating unit that can be applied to the method of manufacturing an organic EL element of the present invention and has an endless transport belt 59 as a substrate holding member. FIG. Only 1 (30) is shown.

As shown in FIG. 5, the endless conveyance belt 59 held by the support roll 54 and the conveyance roll 53A as the substrate holding member is conveyed and installed in the substrate floating portion 55 in the same manner as the method shown in FIG. The porous substrate levitation unit 56 blows and sucks compressed gas for levitation of the substrate to the substrate, thereby applying the substrate while floating the substrate.

When such an endless conveying belt 59 is used as a substrate holding member, it is preferable to use a metal endless belt in which a large number of pores having durability for bending or the like are arranged.

In the manufacturing flow of the series of organic EL elements described above, the second film forming environment 40 (area 2) is not performed without drying in the drying sections H1 to H4 in the first film forming environment 30 (area 1, Stages 1 to 4). ) May be collectively dried.

[Coating environment for organic functional layer group]
In the method for manufacturing an organic EL device of the present invention as shown in FIGS. 2 and 4, for example, a hole injection layer 3, a hole transport layer 4, and a light emitting layer 5 are formed on a single substrate P on which an anode is formed. The environmental (atmosphere) conditions in the step of forming the organic functional layer group 20 such as the electron transport layer 6 and the electron injection layer 7 and the subsequent drying step are mainly as follows:
(I) Using each organic functional layer coating liquid constituting the organic functional layer group, in the first atmosphere 30 (area 1) in which the volume concentration of a gas other than the inert gas is 500 ppm or more, FIG. 2 and FIG. Applying and laminating a plurality of organic functional layers in an inline manner by die coating on the anode 2 of the single-wafer substrate P according to the described steps;
(Ii) In the first atmosphere 30 (area 1), the organic functional layer group after applying and laminating each organic functional layer by the die coating method is offline, and the volume concentration of gas other than the inert gas is 200 ppm or less. Step (baking step) for drying in atmosphere 2 (area 2) of No. 2;
Can be configured.

In the step (i), the compressed gas for flying the substrate in the step shown in FIG. 4 is also preferably a gas having a volume concentration of a gas other than the inert gas of 500 ppm or more.

In the present invention, in the step (i), as a method for forming each organic functional layer, a die coating method that is a wet process is used.

Examples of the solvent used to dissolve or disperse the organic EL material when preparing each organic functional layer coating solution according to the present invention include ketones such as methyl ethyl ketone and cyclohexanone, fatty acid esters such as ethyl acetate, diesters, and the like. Halogenated hydrocarbons such as chlorobenzene, aromatic hydrocarbons such as toluene, xylene, mesitylene, cyclohexylbenzene, aliphatic hydrocarbons such as cyclohexane, decalin, dodecane, dimethylformamide (DMF), dimethyl sulfoxide (DMSO), etc. These organic solvents can be used. Moreover, as a dispersion method, it can disperse | distribute by dispersion methods, such as an ultrasonic wave, high shear force dispersion | distribution, and media dispersion | distribution.

In the present invention, the liquid preparation step for dissolving or dispersing the organic EL material is preferably performed under an inert gas atmosphere, and the organic functional layer is applied until it is applied onto the substrate by the flow shown in FIGS. It is preferable that the coating solution is a step that is not exposed to the coating atmosphere.

In the method for manufacturing an organic EL element according to the present invention, the atmosphere (first film forming environment 30 (area 1)) and the compressed gas for floating the substrate when forming each organic functional layer are other than the inert gas. The volume concentration of the gas is preferably 500 ppm or more, which is considered optimal for forming a coating film of each organic functional layer.

Examples of the gas other than the inert gas in the present invention include O ₂ , O ₃ , H ₂ O, NOx, SOx and the like, preferably O ₂ and H ₂ O, and most preferable from the viewpoint of production cost. Is the atmosphere.

The inert gas in the present invention is preferably a rare gas such as nitrogen gas, argon gas, or xenon gas, and most preferably nitrogen gas in terms of production cost.

When forming each of these organic functional layers, after applying the first organic functional layer coating solution on the substrate, if the coating interval of the next organic functional layer is too long, the inert gas in the coating atmosphere In the present invention, the effect of other gases does not remain on the outermost surface of the coating film, and gas molecules other than the inert gas enter the layer, resulting in a decrease in the performance of the organic EL element. As shown in 2, it is characterized in that it is continuously laminated without leaving a large coating interval.

In the step (ii), the coated and laminated organic functional layer group is collectively dried.

Drying as used herein refers to a step of finally reducing the residual solvent ratio to 0.2% or less when the total solvent content of the laminated film immediately after coating is 100%.

As the means for drying, generally used ones can be used, and examples thereof include reduced pressure or pressure drying, heat drying, air drying, IR drying, and electromagnetic wave drying. Of these, heat drying is preferable, and the temperature is equal to or higher than the boiling point of the solvent having the lowest boiling point among the solvents constituting the organic functional layer coating solution, and the material having the lowest Tg among the Tg of the organic functional layer material (Tg + 20) Most preferably, the temperature is maintained at a temperature lower than ° C. In the present invention, more specifically, it is preferable to hold and dry at 80 ° C. or higher and 150 ° C. or lower, and more preferable to hold and dry at 100 ° C. or higher and 130 ° C. or lower. The drying time is preferably 5 minutes or more and 300 minutes or less.

It is preferable that the atmosphere at the time of drying the coating liquid after coating / lamination is an atmosphere in which the volume concentration of a gas other than the inert gas is 200 ppm or less.

In the method for producing an organic EL device according to the present invention, the second film-forming environment 40 (area 2) is also dried in an environment where the volume concentration of a gas other than the inert gas is 200 ppm or less even in the step (ii). It is preferable to have the process to make.

Examples of gases other than the inert gas applicable in the step (ii) include O ₂ , O ₃ , H ₂ O, NOx, and SOx.

Further, as the inert gas, nitrogen gas and rare gases such as argon gas and xenon gas are preferable, and nitrogen gas is most preferable in terms of manufacturing cost.

[Coater]
In general, examples of wet coating methods include spin coating, casting, die coating, blade coating, roll coating, ink jet, printing, spray coating, and curtain coating. The invention is characterized in that a die coating method is used from the viewpoint of forming a highly accurate and uniform thin film.

3 and 6 are a schematic sectional view of a slit type die coater applicable by the die coating method according to the present invention and a schematic view of a state in which coating is performed using the slit type die coater. That is, FIG. 3 and FIG. 6A is a schematic cross-sectional view of a state where coating is performed using a slit type die coater which is a pre-measuring type coating method. FIGS. 3 and 6B are schematic perspective views of the slit type die coater shown in FIGS.

In the figure, C indicates a slit type die coater. The slit type die coater C has two blocks 101a, a block 101b, a side plate 101c, and a side plate 101d, and is assembled by fastening with bolts or the like. Reference numeral 102 a denotes a notch provided at the end of the application width at the tip of the lip 103. Reference numeral 102 b denotes a notch provided at the end of the application width at the tip of the lip 103. The lip 103 has a back lip 103a and a front lip 103b.

104 indicates a slit formed by a gap between the block 101a and the block 101b, and 105 is a part for temporarily storing a coating liquid called a manifold, and the coating liquid is fed into the coating liquid supply pipe 106 here.

The coating liquid stored in the coating width direction by the manifold 105 passes through the slit 104 and is supplied between the lip 103 and the single-wafer substrate P from the slit outlet 104a at the tip of the slit 104, and is applied. The supplied coating solution forms a bead and is coated on a single substrate P to form a coating film 107.

The pressure at the slit outlet of the bead portion of the coating liquid supplied from the slit outlet 104a is applied on the single substrate P in a negative or zero state.

As shown in FIG. 3 and FIG. 6, the coating method using the slit type die coater C is a method that is performed without providing a decompression chamber.

The application using the slit type die coater C as shown in FIGS. 3 and 6 is performed in accordance with the start of the application, with the required application liquid being supplied from the slit outlet, and moving means (not used) from the standby position to the application position. ) To detect the alignment mark provided on the substrate, which will be described later, and according to the information, when the substrate reaches the coating position, the coating solution is fed and the lip 103 at the tip of the coating coater C is removed. This is a coating method in which a bead is formed in the coater gap between the lip and the substrate P, and the coating liquid is transferred to the substrate P (with liquid).

At this time, in the slit type die coater C shown in FIG. 6, the substrate P is supplied with the compressed gas A supplied from the substrate floating unit via the substrate holding member 32 and the vacuum pump as shown in FIG. By performing suction B (not shown) and floating the substrate at a certain height H2 from the substrate holding member 32, the height H2 (also referred to as a bead gap) between the lip 103 at the tip of the coating coater C and the substrate surface. ) Is controlled to a desired condition, and a stable bead is formed and applied.

At this time, the gap H2 between the substrate holding member 32 and the substrate bottom, that is, the height at which the substrate floats is preferably in the range of 100 to 300 μm. The height H2 (bead gap) between the lip 103 at the tip of the coating coater C and the substrate surface, which is fixed, is preferably 100 to 700 μm, more preferably 200 to 500 μm. If the bead gap is 100 μm or more, the occurrence of coating stripes can be suppressed, and if it is 700 μm or less, the occurrence of liquid breakage or the like can be prevented.

In the method for producing an organic EL device of the present invention, an organic functional layer is applied on a substrate as shown in FIGS. 2 to 3 and 4 to 6 using a die coater. The pattern of the layer may be a method of uniformly applying to almost the entire surface of the substrate, or a method of forming an organic functional layer by applying a specific pattern, for example, a stripe pattern or a lattice pattern in a specific pattern. good.

Here, the case where the coater C is fixed while the coater is fixed is described. However, in the present invention, the case where the substrate P is fixed and the coater C is movable, or both the substrate P and the coater are fixed. Including moving case.

[Substrate floating unit]
The organic EL device manufacturing method of the present invention is characterized in that an organic functional layer is applied onto a substrate using a die coater in a state where the substrate is floated from a substrate holding member using a substrate floating unit.

Hereinafter, the detailed structure of the substrate floating unit and the film thickness control method will be described with reference to the drawings.

FIG. 7 is a schematic view showing an example of the configuration of a substrate floating unit applicable to the method for manufacturing an organic EL element of the present invention.

The substrate floating unit shown in FIG. 7 is a schematic diagram showing in more detail the configuration of the substrate floating unit 55 shown in FIG. 4 and the substrate floating unit 56 installed therein.

7, the substrate P is disposed on the substrate holding member 32, and the substrate floating portion 55 is disposed on the back surface of the substrate holding member 32.

The substrate floating portion 55 is provided with two front and rear compressed gas supply units 300A and 300B each including a chamber 302 for supplying a compressed gas A1 for floating the substrate P and a substrate floating unit 301. The substrate floating unit 301 is made of a porous material having a gas passage that penetrates in the film thickness direction as described above.

In addition, a decompression unit 306 for intake A3 is provided between the two compressed gas supply units 300A and 300B.

In the present invention, the floating amount H1 of the substrate P relative to the substrate holding member 32 is detected by the position detection sensor 307 provided in the vicinity of the substrate holding member 32.

Based on the detected data, based on the information from the position detection sensor 307, the compressed gas flow rate is adjusted so that the height H2 (bead gap) between the tip lip of the coating coater Co and the surface of the substrate P becomes a desired condition. The supply amount A1 is controlled through the information line 308 to the operation amount of the gas blowing pumps 304A and 304B. Similarly, by controlling the operating amount of the vacuum pump 305 via the information line 309 and balancing the conditions of the intake air A3, a desired substrate flying height H2 is realized.

At this time, as a method of transporting the levitated substrate in the right direction of the paper, for example, a method of transporting the substrate by pushing the rear end portion of the substrate with an air cylinder or the like, or in two installed compressed gas supply units 300, A method of setting the pressure of the compressed gas A1 supplied from the compressed gas supply unit 300A arranged on the side higher than the pressure of the compressed gas A3 supplied from the compressed gas supply unit 300B arranged on the downstream side, or As shown as A2 in FIG. 7, a method of arranging the discharge direction of the compressed gas in the conveying direction, and the like can be mentioned.

Further, in the present invention, the substrate floating unit having such a configuration can be obtained as a commercial product. For example, a non-contact transfer device manufactured by Myotoku Co., Ltd. “Floating transfer unit near float LTU series” Etc.

FIG. 8 shows an example of another configuration of the substrate floating unit applicable to the method for manufacturing the organic EL element of the present invention.

The substrate floating unit 310 shown in FIG. 8 is installed over the entire surface of the substrate holding member 32, and two pairs of compressed gas blowing units 311 for floating the substrate P and a suction unit for reducing the pressure by the vacuum pump 305. 312 are alternately arranged on the entire surface to constitute a substrate floating unit 310.

An independent pump 304 is connected to each of the two pairs of compressed gas blowing sections 311, and the supply amount A of the compressed gas is determined based on the floating amount H1 information of the substrate P with respect to the substrate holding member 32 by the position detection sensor 307. The operation amount of P1 to P9 of the gas blower pump 304 is controlled via the information line 308. Similarly, the intake air amount B of the vacuum pump 305 is controlled based on the floating amount H1 information of the substrate P with respect to the substrate holding member 32 by the position detection sensor 307.

In order to transport the substrate P to the downstream side, for example, the pumps 0P1 to P9 are operated so that the compressed gas supply amount A gradually decreases from the upstream pump P1 to the downstream pump P9. It is preferred to control the amount.

〔Alignment mark〕
In the method for producing an organic electroluminescent element of the present invention, an alignment mark is provided on a single wafer substrate, the alignment mark is detected, and an organic functional layer forming coating is applied from the die coater to the single wafer substrate. It is preferable to control the supply and stop of the liquid. In addition, by detecting the position information of the substrate being conveyed by the alignment mark according to the present invention, the substrate floating unit is operated in accordance with the application start time information to float the substrate.

As an alignment mark, as shown in FIG. 9, it can be applied to each corner portion of the substrate as a corner registration mark. There are no particular restrictions on the method of applying the alignment mark. For example, under a reduced-pressure environment condition of about 5 × 10 ⁻¹ Pa, a cross formed by an indium tin oxide (ITO) film having a thickness of 120 nm is formed at the four corners of the substrate. The mark can be formed by forming a film by a sputtering method.

In the present invention, as a method for detecting the position of the substrate using the alignment mark, a CCD camera 401 is installed on the upstream side of Stage 1 which is the first coating zone so as to cover the entire width of the substrate, Based on the detection and position information and the substrate conveyance speed information, the application start time (supply start time of the organic functional layer forming coating liquid to the die coater) and the application completion time (organic function) on the substrate P are determined. The application of the coating liquid for layer formation to the die coater is instructed to each coater (Co1 to Co3 shown in FIG. 9) via the feedback circuit 404 to control the application. At the same time, although not shown in FIG. 9, based on the alignment mark detection and position information by the CCD camera and the substrate transport speed information, the substrate floating unit is operated at a predetermined time to lift the substrate. Apply.

[Wiping cleaning equipment]
In the method for producing an organic electroluminescent element of the present invention, it is preferable to perform a wiping cleaning process on the lip portion of the die coater when the coating liquid for forming the organic functional layer on the die coater is stopped.

That is, the supply of the organic functional layer forming coating liquid to the die coater is stopped in the uncoated stage due to the detection of the alignment mark by the CCD camera and the position information. At this time, in the lip portion of the die coater, the coating liquid for forming the organic functional layer, which has been stopped, forms a meniscus and is directly exposed to the outside air. As a result, the coating film is formed by evaporating the solvent from the surface of the coating liquid for forming the organic functional layer in contact with the outside air, and the droplets of the coating liquid for forming the organic functional layer scattered during the coating process are formed on the die coater. It solidifies at the lip and causes a coating failure.

In order to eliminate the cause of the above coating failure, the wiping cleaning process is performed on the lip surface of the die coater when the coating solution to the die coater is stopped.

An example of a specific wiping cleaning processing method and wiping cleaning processing apparatus will be described with reference to the drawings.

As shown in FIG. 9, by detecting the alignment mark by the CCD camera and the position information, as shown in Stage 2 and Stage 3, the die coater Co 2 and Co 3 are respectively supplied at the time when supply of the organic functional layer forming coating liquid to the die coater is stopped. The lip surface of the die coater is cleaned using a cleaning liquid by moving the wiping cleaning processing apparatus 403 from the coating position to the position of the wiping cleaning processing apparatus 403. When cleaning is completed and the coating start time is reached, information is again transmitted to the die coater via the feedback circuit 404. After the die coater is moved to each coating position, the organic functional layer forming coating solution is supplied at the coating start time. Start application.

FIG. 10 shows an example of a main configuration of a die coater wiping cleaning apparatus applicable to the present invention.

As shown in FIG. 10, the wiping cleaning device 403 includes a wiping member 409 that protrudes upward and a sheet-like flexible member 408 that supports the wiping member 409 in a box-shaped housing 407. Then, after the wipe unit 406 itself is moved upward by a drive source such as a motor (not shown), the die coater is moved to the upper part of the wiping member 409, and the nozzle surface of the wiping member 409 and the head Co (103 shown in FIG. 6). ) Are in contact with each other, the wiping member 409 rubs the nozzle surface 103 of the head Co to remove the sticking matter adhering to the entire nozzle surface 103, the dry film on the meniscus portion, and the like. When the wiping operation is completed, the wiping unit 406 is lowered, and the contact state between the wiping member 409 and the nozzle surface 103 is released.

Further, a cleaning liquid tank 410 is connected to the wipe unit 406 via a liquid supply path 405. A cleaning liquid supply valve (not shown) is provided in the middle of the liquid supply path 405.

The liquid supply path 405 is a path through which the cleaning liquid flows by the operation of the cleaning liquid supply valve, and is constituted by, for example, a resin tube.

Since the cleaning liquid tank 410 is disposed at a position higher than the position of the wipe unit 406 (the position of the wiping member 409), the cleaning liquid can be easily supplied to the wiping member 409 due to a water head difference.

As the cleaning liquid, it is required to have a function of reliably wiping the organic functional layer forming coating liquid adhering to the nozzle surface by dissolving, redispersing, and softening. Therefore, the cleaning liquid preferably contains a solution component constituting the coating liquid for forming an organic functional layer, for example, various solvents, water, a surfactant, a basic compound, and the like, but is not limited thereto. Is not to be done. In particular, when a solvent having a low surface tension is contained, it is effective because it easily penetrates into the dried coating material for forming a functional layer. Moreover, it is preferable to contain a basic compound in order to accelerate | stimulate re-dissolution or re-dispersion of resin etc. which are contained in the coating liquid for organic functional layer formation.

<< Constituent materials for organic EL elements >>
Subsequently, the detail of the organic functional layer which comprises the organic EL element which concerns on this invention is demonstrated.

(1) Injection layer: hole injection layer, electron injection layer In the organic EL device according to the present invention, the injection layer can be provided as necessary. The injection layer includes an electron injection layer and a hole injection layer, and may be present between the anode and the light emitting layer or the hole transport layer and between the cathode and the light emitting layer or the electron transport layer as described above.

The injection layer referred to in the present invention is a layer provided between the electrode and the organic functional layer in order to lower the driving voltage and improve the light emission luminance. “The organic EL element and its industrialization front line (November 30, 1998, NT. 2) Chapter 2 “Electrode Materials” (pages 123 to 166) of “Part 2” of S. Co., Ltd.) and includes a hole injection layer and an electron injection layer.

The details of the hole injection layer are described, for example, in JP-A-9-45479, JP-A-9-260062, and JP-A-8-288069. Injection materials include triazole derivatives, oxadiazole derivatives, imidazole derivatives, pyrazoline derivatives and pyrazolone derivatives, phenylenediamine derivatives, arylamine derivatives, amino-substituted chalcone derivatives, oxazole derivatives, styrylanthracene derivatives, fluorenone derivatives, hydrazone derivatives, stilbene derivatives. , Polymers containing silazane derivatives, aniline copolymers, polyarylalkane derivatives, or conductive polymers, preferably polythiophene derivatives, polyaniline derivatives, polypyrrole derivatives, more preferably Thiophene derivatives.

The details of the electron injection layer are described in, for example, JP-A-6-325871, JP-A-9-17574, and JP-A-10-74586, and specific examples thereof include strontium and aluminum. A metal buffer layer, an alkali metal compound buffer layer typified by lithium fluoride, an alkaline earth metal compound buffer layer typified by magnesium fluoride, and an oxide buffer layer typified by aluminum oxide. In the present invention, the buffer layer (injection layer) is desirably a very thin film, and potassium fluoride and sodium fluoride are preferable. The film thickness is about 0.1 nm to 5 μm, preferably 0.1 to 100 nm, more preferably 0.5 to 10 nm, and most preferably 0.5 to 4 nm.

In the method for producing an organic EL element of the present invention, the electron injection layer is preferably formed by a vapor deposition method using a vacuum vapor deposition apparatus or the like instead of a wet coating method.

(2) Hole transport layer As the hole transport material constituting the hole transport layer, the same compounds as those applied in the hole injection layer can be used, but further, porphyrin compounds, aromatics It is preferable to use a tertiary amine compound and a styrylamine compound, particularly an aromatic tertiary amine compound.

Representative examples of aromatic tertiary amine compounds and styrylamine compounds include N, N, N ′, N′-tetraphenyl-4,4′-diaminophenyl; N, N′-diphenyl-N, N′— Bis (3-methylphenyl)-[1,1′-biphenyl] -4,4′-diamine (TPD); 2,2-bis (4-di-p-tolylaminophenyl) propane; 1,1-bis (4-di-p-tolylaminophenyl) cyclohexane; N, N, N ′, N′-tetra-p-tolyl-4,4′-diaminobiphenyl; 1,1-bis (4-di-p-tolyl) Aminophenyl) -4-phenylcyclohexane; bis (4-dimethylamino-2-methylphenyl) phenylmethane; bis (4-di-p-tolylaminophenyl) phenylmethane; N, N'-diphenyl-N, N ' Di (4-methoxyphenyl) -4,4'-diaminobiphenyl; N, N, N ', N'-tetraphenyl-4,4'-diaminodiphenyl ether; 4,4'-bis (diphenylamino) quadriphenyl N, N, N-tri (p-tolyl) amine; 4- (di-p-tolylamino) -4 '-[4- (di-p-tolylamino) styryl] stilbene; 4-N, N-diphenylamino -(2-diphenylvinyl) benzene; 3-methoxy-4'-N, N-diphenylaminostilbenzene; N-phenylcarbazole, as well as those described in US Pat. No. 5,061,569 Having four condensed aromatic rings in the molecule, for example, 4,4'-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (NPD), JP-A-4-3 4,4 ′, 4 ″ -tris [N- (3-methylphenyl) -N-phenylamino] triphenylamine in which three triphenylamine units described in Japanese Patent No. 8688 are linked in a starburst type ( MTDATA) and the like.

Furthermore, polymer materials in which these materials are introduced into polymer chains or these materials are used as polymer main chains can also be used. In addition, inorganic compounds such as p-type-Si and p-type-SiC can also be used as the hole injection material and the hole transport material.

JP-A-4-297076, JP-A-2000-196140, JP-A-2001-102175, J. Pat. Appl. Phys. , 95, 5773 (2004), JP-A-11-251067, J. MoI. Huang et. al. It is also possible to use a hole transport material that has so-called p-type semiconducting properties, as described in the literature (Applied Physics Letters 80 (2002), p. 139), JP 2003-519432 A. it can.

In the present invention, the hole transport layer is formed by thinning a coating solution containing the hole transport material by a die coating method. The thickness of the hole transport layer is not particularly limited, but is usually about 5 nm to 5 μm, preferably 5 to 200 nm. The hole transport layer may have a single layer structure composed of one or more of the above materials.

(3) Electron transport layer The electron transport layer is made of a material having a function of transporting electrons, and in a broad sense, an electron injection layer and a hole blocking layer are also included in the electron transport layer. The electron transport layer can be provided as a single layer or a plurality of layers.

Conventionally, in the case of a single electron transport layer and a plurality of layers, an electron transport material (also serving as a hole blocking material) used for an electron transport layer adjacent to the cathode side with respect to the light emitting layer is injected from the cathode. As long as it has a function of transmitting electrons to the light-emitting layer, any material can be selected and used from among conventionally known compounds. For example, fluorene derivatives, carbazole derivatives, azacarbazole And metal complexes such as derivatives, oxadiazole derivatives, triazole derivatives, silole derivatives, pyridine derivatives, pyrimidine derivatives, 8-quinolinol derivatives, and the like.

In addition, metal-free or metal phthalocyanine, or those having terminal ends substituted with an alkyl group or a sulfonic acid group can be preferably used as the electron transporting material.

Among these, carbazole derivatives, azacarbazole derivatives, pyridine derivatives and the like are preferable in the present invention, and more preferably an azacarbazole derivative.

In the present invention, the electron transport layer is formed by a wet process using a die coating method with an electron transport layer coating solution containing the electron transport material, semiconductor nanoparticles (see below), and a fluorinated alcohol solvent.

The thickness of the electron transport layer is not particularly limited, but is usually about 5 nm to 5 μm, preferably 5 to 200 nm. The electron transport layer may have a single layer structure composed of one or more of the above materials.

In the present invention, in addition to the semiconductor nanoparticles, an electron transport layer having a high n property doped with an impurity as a guest material can also be used. Examples thereof include JP-A-4-297076, JP-A-10-270172, JP-A-2000-196140, 2001-102175, J.A. Appl. Phys. 95, 5773 (2004), and the like.

The electron transport layer in the present invention preferably contains an organic alkali metal salt.
There are no particular restrictions on the type of organic substance, but formate, acetate, propionic acid, butyrate, valerate, caproate, enanthate, caprylate, oxalate, malonate, succinate Benzoate, phthalate, isophthalate, terephthalate, salicylate, pyruvate, lactate, malate, adipate, mesylate, tosylate, benzenesulfonate , Preferably formate, acetate, propionate, butyrate, valerate, caprate, enanthate, caprylate, oxalate, malonate, succinate, benzoate, more preferably Is preferably an alkali metal salt of an aliphatic carboxylic acid such as formate, acetate, propionate or butyrate, and the aliphatic carboxylic acid preferably has 4 or less carbon atoms. Most preferred is acetate.

The type of alkali metal of the organic alkali metal salt is not particularly limited, and examples thereof include Na, K, and Cs, preferably K, Cs, and more preferably Cs. Examples of the alkali metal salt of the organic substance include a combination of the organic substance and the alkali metal, preferably, formic acid Li, formic acid K, Na formic acid, formic acid Cs, Li acetate, K acetate, Na acetate, Cs acetate, Lipropionate, Propionic acid Na, propionic acid K, propionic acid Cs, oxalic acid Li, oxalic acid Na, oxalic acid K, oxalic acid Cs, malonic acid Li, malonic acid Na, malonic acid K, malonic acid Cs, succinic acid Li, succinic acid Na, succinic acid K, succinic acid Cs, benzoic acid Li, benzoic acid Na, benzoic acid K, benzoic acid Cs, more preferably Li acetate, K acetate, Na acetate, Cs acetate, most preferably Cs acetate.

The content of these dope materials is preferably 1.5 to 35% by mass, more preferably 3 to 25% by mass, and most preferably 5 to 15% by mass with respect to the electron transport layer to be added.

(4) Light emitting layer The light emitting layer constituting the organic EL device according to the present invention is a layer that emits light by recombination of electrons and holes injected from the electrode, the electron transport layer, or the hole transport layer, and emits light. The portion to be formed may be in the light emitting layer or at the interface between the light emitting layer and the adjacent layer.

The structure of the light emitting layer according to the present invention is not particularly limited as long as the light emitting material included satisfies the above requirements.

Also, there may be a plurality of layers having the same emission spectrum or emission maximum wavelength. It is preferable to have a non-light emitting intermediate layer between each light emitting layer.

In the present invention, the total thickness of the light emitting layers is preferably in the range of 1 to 100 nm, and more preferably 50 nm or less because a lower driving voltage can be obtained. In addition, the sum total of the film thickness of the light emitting layer as used in this invention is a film thickness also including the said intermediate | middle layer, when a nonluminous intermediate | middle layer exists between light emitting layers.

It is preferable to adjust the film thickness of each light emitting layer to a range of 1 to 50 nm. There is no particular limitation on the relationship between the film thicknesses of the blue, green and red light emitting layers.

In the present invention, the light emitting layer is formed by forming a light emitting layer forming coating solution containing a light emitting material and a host compound described later by a die coating method.

In the present invention, a plurality of light emitting materials may be mixed in each light emitting layer, or a phosphorescent light emitting material and a fluorescent light emitting material may be mixed and used in the same light emitting layer.

In the present invention, the light emitting layer preferably contains a host compound and a light emitting material (also referred to as a light emitting dopant compound) and emits light from the light emitting material.

<4.1: Host compound>
As the host compound contained in the light emitting layer of the organic EL device according to the present invention, a compound having a phosphorescence quantum yield of phosphorescence emission at room temperature (25 ° C.) of less than 0.1 is preferable. More preferably, the phosphorescence quantum yield is less than 0.01. Moreover, it is preferable that the volume ratio in the layer is 50% or more among the compounds contained in a light emitting layer.

As the host compound, known host compounds may be used alone or in combination of two or more. By using a plurality of types of host compounds, it is possible to adjust the movement of charges, and the organic EL element can be made highly efficient. Moreover, it becomes possible to mix different light emission by using multiple types of luminescent material mentioned later, and can thereby obtain arbitrary luminescent colors.

The light emitting host used in the present invention may be a conventionally known low molecular compound or a high molecular compound having a repeating unit, and a low molecular compound having a polymerizable group such as a vinyl group or an epoxy group (polymerizable light emission). However, when a high molecular weight material is used, a phenomenon in which the compound is likely to be difficult to escape, such as swelling or gelation, due to the compound taking in the solvent is likely to occur. Specifically, it is preferable to use a material having a molecular weight of 2,000 or less at the time of application, and it is more preferable to use a material having a molecular weight of 1,000 or less at the time of application.

In the drying process, when a low-molecular material is used for the light-emitting host, contamination due to solvent migration from the adjacent layer in contact with the light-emitting layer is likely to occur, and recombination of holes and electrons may be hindered when the device is driven. The details are unknown by selecting the manufacturing method and material of the invention, but the surface oxide film or hydrogen bond film is formed on each layer to reduce the effect of inter-layer transfer of life deterioration factors such as solvents, and long life and storage It is considered that a light-emitting element having excellent stability can be obtained.

As the known host compound, a compound that has a hole transporting ability and an electron transporting ability, prevents the emission of light from being increased in wavelength, and has a high Tg (glass transition temperature) is preferable. Here, the glass transition point (Tg) is a value determined by a method based on JIS-K-7121 using DSC (Differential Scanning Colorimetry).

Specific examples of known host compounds include compounds described in the following documents. For example, Japanese Patent Laid-Open Nos. 2001-257076, 2002-308855, 2001-313179, 2002-319491, 2001-357777, 2002-334786, 2002-8860 Gazette, 2002-334787, 2002-15871, 2002-334788, 2002-43056, 2002-334789, 2002-75645, 2002-338579 No. 2002-105445, No. 2002-343568, No. 2002-141173, No. 2002-352957, No. 2002-203683, No. 2002-363227, No. 2002-231453. No. 2003-3165, No. 2002-234888, No. 2003-27048, No. 2002-255934, No. 2002-286061, No. 2002-280183, No. 2002-299060. No. 2002-302516, No. 2002-305083, No. 2002-305084, No. 2002-308837, and the like.

The host compound used in the present invention is preferably a carbazole derivative, more preferably a carbazole derivative and a dibenzofuran compound.

<4.2: Luminescent dopant>
As the light emitting dopant according to the present invention, a fluorescent dopant or a phosphorescent dopant can be used. From the viewpoint of obtaining an organic EL element with higher luminous efficiency, the light emitting layer or light emitting unit of the organic EL element according to the present invention is used. As a light emitting dopant to be used, it is preferable to contain a phosphorescent dopant simultaneously with the above-mentioned light emitting host.

<Phosphorescent dopant>
The phosphorescent dopant according to the present invention is a compound in which light emission from an excited triplet is observed. Specifically, the phosphorescent dopant is a compound that emits phosphorescence at room temperature (25 ° C.) and has a phosphorescence quantum yield of 25. Although it is defined as a compound of 0.01 or more at ° C., a preferable phosphorescence quantum yield is 0.1 or more.

The phosphorescent quantum yield can be measured by the method described in Spectroscopic II, page 398 (1992 edition, Maruzen) of the Fourth Edition Experimental Chemistry Course 7. Although the phosphorescence quantum yield in a solution can be measured using various solvents, the phosphorescence dopant according to the present invention achieves the phosphorescence quantum yield (0.01 or more) in any solvent. That's fine.

There are two types of emission of phosphorescent dopants in principle. One is the recombination of carriers on the light-emitting host on which carriers are transported to generate the excited state of the light-emitting host, and this energy is transferred to the phosphorescent dopant. Energy transfer type to obtain light emission from the phosphorescent dopant, another is that the phosphorescent dopant becomes a carrier trap, carrier recombination occurs on the phosphorescent dopant, and light emission from the phosphorescent dopant is obtained Although it is a carrier trap type, in any case, it is a condition that the excited state energy of the phosphorescent dopant is lower than the excited state energy of the light emitting host.

The phosphorescent dopant can be appropriately selected from known materials used for the light emitting layer of the organic EL element.

The phosphorescent dopant applicable to the present invention is preferably a complex compound containing a metal belonging to Group 8, Group 9, or Group 10 of the periodic table of elements, and more preferably an iridium compound, a platinum compound, or an osmium compound. , Palladium compounds and rhodium compounds, and most preferred are iridium compounds and platinum compounds.

Specifically, it is a compound described in the following patent publications, for example, International Publication No. 00/70655 pamphlet, JP 2002-280178 A, 2001-181616, 2002-280179, 2001-181617, 2002-280180, 2001-247859, 2002-299060, 2001-313178, 2002-302671, 2001-345183, 2002-324679, WO 02/15645, JP-A 2002-332291, 2002-50484, 2002-332292, 2002-83684, 2002-540572 Publication, JP 002-117978, 2002-338588, 2002-170684, 2002-352960, WO01 / 93642, JP2002-50483, 2002-1000047 No. 2002-173684, No. 2002-359082, No. 2002-175484, No. 2002-363552, No. 2002-184582, No. 2003-7469, No. 2002-525808 JP2003-7471, JP2002-525833A, JP2003-31366A, 2002-226495, 2002-234894, 2002-233506, 2002-2417. No. 1, No. 2001-319779, No. 2001-319780, No. 2002-62824, No. 2002-1000047, No. 2002-203679, No. 2002-343572, No. 2002-203678. Can be used.

In addition, these exemplified compounds are, for example, Inorg. Chem. , 40, 1704 to 1711.

In the present invention, the light emitting dopant contained in the light emitting layer may be one kind, or may contain two or more kinds of light emitting dopants having different light emission maximum wavelengths. When two or more kinds of light emitting dopants are contained, a concentration gradient may be formed in the thickness direction of the light emitting layer for all the light emitting dopants, but only one kind of light emitting dopant may be formed. When the concentration gradient is formed only for one kind of light emitting dopant, it is preferable to form the concentration gradient for the light emitting dopant having the shortest wavelength of the light emission maximum wavelength.

"anode"
As the anode constituting the organic EL device, an electrode material made of a metal, an alloy, an electrically conductive compound or a mixture thereof having a high work function (4 eV or more) is preferably used. Specific examples of such electrode materials include metals such as Au, and conductive transparent materials such as CuI, indium tin oxide (ITO), SnO ₂ , and ZnO. Alternatively, an amorphous material such as IDIXO (In ₂ O ₃ —ZnO) capable of forming a transparent conductive film may be used. For the anode, these electrode materials may be formed into a thin film by a method such as vapor deposition or sputtering, and a desired shape pattern may be formed by a photolithography method, or when pattern accuracy is not so high (about 100 μm or more) A pattern may be formed through a mask having a desired shape at the time of vapor deposition or sputtering of the electrode material. Or when using the substance which can be apply | coated like an organic electroconductivity compound, wet film-forming methods, such as a printing system and a coating system, can also be used. When light emission is taken out from the anode, it is desirable that the transmittance is greater than 10%, and the sheet resistance as the anode is preferably several hundred Ω / □ or less. Further, although the film thickness depends on the material, it is usually in the range of 10 to 1000 nm, preferably in the range of 10 to 200 nm.

"cathode"
On the other hand, as the cathode, a material having a low work function (4 eV or less) metal (referred to as an electron injecting metal), an alloy, an electrically conductive compound, and a mixture thereof as an electrode material is used. Specific examples of such electrode materials include sodium, sodium-potassium alloy, magnesium, lithium, magnesium / copper mixture, magnesium / silver mixture, magnesium / aluminum mixture, magnesium / indium mixture, aluminum / aluminum oxide (Al ₂ O ₃ ) Mixtures, indium, lithium / aluminum mixtures, rare earth metals and the like. Among these, from the point of durability against electron injection and oxidation, etc., a mixture of an electron injecting metal and a second metal which is a stable metal having a larger work function than this, for example, a magnesium / silver mixture, Magnesium / aluminum mixtures, magnesium / indium mixtures, aluminum / aluminum oxide (Al ₂ O ₃ ) mixtures, lithium / aluminum mixtures, aluminum and the like are preferred. The cathode can be produced by forming a thin film of these electrode materials by a method such as vapor deposition or sputtering. The sheet resistance as the cathode is preferably several hundred Ω / □ or less, and the film thickness is usually selected in the range of 10 nm to 5 μm, preferably 50 to 200 nm. In order to transmit the emitted light, if either one of the anode or the cathode of the organic EL element is transparent or translucent, the light emission luminance is improved, which is convenient.

In addition, a transparent or translucent cathode can be produced by forming the above metal on the cathode with a film thickness of 1 to 20 nm and then forming the conductive transparent material mentioned in the description of the anode thereon. By applying this, an organic EL element in which both the anode and the cathode are transmissive can be produced.

"substrate"
There are no particular limitations on the type of glass, plastic, etc., which can be used in the organic EL device according to the present invention (hereinafter also referred to as a support base, support substrate, substrate, support, etc.), and it is transparent. Or opaque. When extracting light from the support substrate side, the support substrate is preferably transparent. Examples of the transparent support substrate preferably used include glass, quartz, and a transparent resin film, and a glass substrate is particularly preferable.

Examples of the glass substrate applicable to the present invention include soda lime glass, barium / strontium-containing glass, lead glass, aluminosilicate glass, borosilicate glass, barium borosilicate glass, and quartz.

Examples of the resin film include polyesters such as polyethylene terephthalate (PET) and polyethylene naphthalate (PEN), polyethylene, polypropylene, cellophane, cellulose diacetate, cellulose triacetate, cellulose acetate butyrate, cellulose acetate propionate (CAP), Cellulose esters such as cellulose acetate phthalate (TAC) and cellulose nitrate or derivatives thereof, polyvinylidene chloride, polyvinyl alcohol, polyethylene vinyl alcohol, syndiotactic polystyrene, polycarbonate, norbornene resin, polymethylpentene, polyether ketone, polyimide , Polyethersulfone (PES), polyphenylene sulfide, polysulfone , Polyetherimide, polyetherketoneimide, polyamide, fluororesin, nylon, polymethylmethacrylate, acrylic or polyarylates, cyclone resins such as Arton (trade name, manufactured by JSR) or Appel (trade name, manufactured by Mitsui Chemicals) Etc.

On the surface of the resin film, an inorganic film, an organic film or a hybrid film of both may be formed. The water vapor permeability (25 ± 0.5 ° C.) measured by a method according to JIS K 7129-1992. And a relative humidity (90 ± 2)% RH) of 0.01 g / (m ² · 24 h) or less is preferable, and oxygen permeability measured by a method according to JIS K 7126-1987. The film is preferably a high barrier film having a degree of 1 × 10 ⁻³ cm ³ / (m ² · 24 h · atm) or less and a water vapor permeability of 1 × 10 ⁻³ g / (m ² · 24 h) or less, More preferably, the water vapor permeability is 1 × 10 ⁻⁵ g / (m ² · 24 h) or less.

As a material for forming the barrier film, any material may be used as long as it has a function of suppressing entry of factors that cause deterioration of the organic EL element such as moisture and oxygen. For example, silicon oxide, silicon dioxide, silicon nitride, or the like is used. Can do. Further, in order to improve the brittleness of the film, it is more preferable to have a laminated structure of these inorganic layers and organic material layers. Although there is no restriction | limiting in particular about the lamination order of an inorganic layer and an organic functional layer, It is preferable to laminate | stack both alternately several times.

The method for forming the barrier film is not particularly limited. For example, the vacuum deposition method, sputtering method, reactive sputtering method, molecular beam epitaxy method, cluster ion beam method, ion plating method, plasma polymerization method, atmospheric pressure plasma A polymerization method, a plasma CVD method, a laser CVD method, a thermal CVD method, a coating method, and the like can be used, but an atmospheric pressure plasma polymerization method as described in JP-A-2004-68143 is particularly preferable.

Examples of the opaque support substrate include metal plates such as aluminum and stainless steel, films, opaque resin substrates, ceramic substrates, and the like.

In the organic EL device according to the present invention, the external extraction efficiency of light emission at room temperature is preferably 1% or more, more preferably 5% or more. Here, the external extraction quantum efficiency (%) = the number of photons emitted to the outside of the organic EL element / the number of electrons sent to the organic EL element × 100.

<< Sealing: Sealing adhesive, sealing member >>
As a sealing means applicable to the organic EL element according to the present invention, for example, a method of adhering a sealing member, an electrode, and a support substrate with an adhesive can be mentioned.

The sealing member may be disposed so as to cover the display area of the organic EL element, and may be a concave plate shape or a flat plate shape. Further, transparency and electrical insulation are not particularly limited.

Specific examples include a glass plate, a polymer plate / film, and a metal plate / film. Examples of the glass plate include soda-lime glass, barium / strontium-containing glass, lead glass, aluminosilicate glass, borosilicate glass, barium borosilicate glass, and quartz. Examples of the polymer plate include polycarbonate, acrylic, polyethylene terephthalate, polyether sulfide, and polysulfone. Examples of the metal plate include those made of one or more metals or alloys selected from the group consisting of stainless steel, iron, copper, aluminum, magnesium, nickel, zinc, chromium, titanium, molybdenum, silicone, germanium, and tantalum.

In the present invention, a polymer film and a metal film can be preferably used because the element can be thinned. Furthermore, the polymer film has an oxygen permeability measured by a method according to JIS K 7126-1987 of 1 × 10 ⁻³ ml / (m ² · 24 h · atm) or less, and conforms to JIS K 7129-1992. The water vapor permeability (25 ± 0.5 ° C., relative humidity (90 ± 2)% RH) measured by the method is preferably 1 × 10 ⁻³ g / (m ² · 24 h) or less.

For processing the sealing member into a concave shape, sandblasting, chemical etching, or the like is used.

Specific examples of the adhesive include photocuring and thermosetting adhesives having reactive vinyl groups of acrylic acid oligomers and methacrylic acid oligomers, and moisture curing adhesives such as 2-cyanoacrylates. Can be mentioned. Moreover, heat | fever and chemical curing types (two-component mixing), such as an epoxy type, can be mentioned. Moreover, hot-melt type polyamide, polyester, and polyolefin can be mentioned. Moreover, a cationic curing type ultraviolet curing epoxy resin adhesive can be mentioned.

In addition, since an organic EL element may deteriorate by heat processing, what can be adhesively cured from room temperature to 80 ° C. is preferable. Further, a desiccant may be dispersed in the adhesive. Application | coating of the adhesive agent to a sealing part may use commercially available dispenser, and may print like screen printing.

It is also preferable that the electrode and the organic functional layer are coated on the outside of the electrode facing the support substrate with the organic functional layer interposed therebetween, and an inorganic or organic layer is formed in contact with the support substrate to form a sealing film. Can be. In this case, the material for forming the film may be any material that has a function of suppressing intrusion of elements that cause deterioration of elements such as moisture and oxygen. For example, silicon oxide, silicon dioxide, silicon nitride, or the like may be used. it can. Further, in order to improve the brittleness of the film, it is preferable to have a laminated structure of these inorganic layers and layers made of organic materials. The method for forming these films is not particularly limited. For example, vacuum deposition, sputtering, reactive sputtering, molecular beam epitaxy, cluster ion beam method, ion plating method, plasma polymerization method, atmospheric pressure plasma A polymerization method, a plasma CVD method, a laser CVD method, a thermal CVD method, a coating method, or the like can be used.

In order to form a gas phase and a liquid phase in the gap between the sealing member and the display area of the organic EL element, an inert gas such as nitrogen or argon, an inert gas such as fluorinated hydrocarbon or silicon oil is used. It is preferable to inject a liquid. A vacuum is also possible. Moreover, a hygroscopic compound can also be enclosed inside.

Examples of the hygroscopic compound include metal oxides (for example, sodium oxide, potassium oxide, calcium oxide, barium oxide, magnesium oxide, aluminum oxide) and sulfates (for example, sodium sulfate, calcium sulfate, magnesium sulfate, cobalt sulfate). Etc.), metal halides (eg calcium chloride, magnesium chloride, cesium fluoride, tantalum fluoride, cerium bromide, magnesium bromide, barium iodide, magnesium iodide etc.), perchloric acids (eg perchloric acid) Barium, magnesium perchlorate, and the like), and anhydrous salts are preferably used in sulfates, metal halides, and perchloric acids.

Sealing includes casing type sealing (can sealing) and close contact type sealing (solid sealing), but solid sealing is preferable from the viewpoint of thinning. Moreover, when producing a flexible organic EL element, since sealing is also required for the sealing member, solid sealing is preferable.

As the sealing adhesive according to the present invention, a thermosetting adhesive, an ultraviolet curable resin, or the like can be used, but preferably a thermosetting adhesive such as an epoxy resin, an acrylic resin, or a silicone resin, more preferably moisture resistant. It is an epoxy thermosetting adhesive resin that is excellent in water resistance and water resistance and has little shrinkage during curing.

The water content of the sealing adhesive according to the present invention is preferably 300 ppm or less, more preferably 0.01 to 200 ppm, and most preferably 0.01 to 100 ppm.

The moisture content referred to in the present invention may be measured by any method. For example, a volumetric moisture meter (Karl Fischer), an infrared moisture meter, a microwave transmission moisture meter, a heat-dry weight method, GC / MS , IR, DSC (differential scanning calorimeter), TDS (temperature programmed desorption analysis). Further, using a precision moisture meter AVM-3000 (Omnitech) or the like, moisture can be measured from a pressure increase caused by evaporation of moisture, and moisture content of a film or a solid film can be measured.

In the present invention, the moisture content of the sealing adhesive can be adjusted by, for example, placing it in a nitrogen atmosphere with a dew point temperature of −80 ° C. or lower and an oxygen concentration of 0.8 ppm, and changing the time. Further, it can be dried in a vacuum state of 100 Pa or less while changing the time. Further, the sealing adhesive can be dried only with an adhesive, but can also be placed in advance on the sealing member and dried.

When close sealing (solid sealing) is performed, as the sealing member, for example, a 50 μm thick PET (polyethylene terephthalate) laminated with an aluminum foil (30 μm thick) is used. Using this as a sealing member, it is uniformly applied to the aluminum surface using a dispenser, a sealing adhesive is placed in advance, the resin substrate 1 and the sealing member 5 are aligned, and both are pressure-bonded ( 0.1-3 MPa) and a temperature of 80-180 ° C. for close contact / bonding (adhesion), and close sealing (solid sealing).

Heating or pressure bonding time varies depending on the type, amount, and area of the adhesive, but temporary bonding is performed at a pressure of 0.1 to 3 MPa, and heat curing time is in the range of 5 seconds to 10 minutes at a temperature of 80 to 180 ° C. Just choose.

It is preferable to use a heated pressure-bonding roll because pressure bonding (temporary bonding) and heating can be performed simultaneously, and internal voids can be eliminated simultaneously.

Further, as a method for forming the adhesive layer, a coating method such as roll coating, spin coating, screen printing, spray coating, or the like can be used using a dispenser depending on the material.

As described above, solid sealing is a form in which there is no space between the sealing member and the organic EL element substrate and the resin is covered with a cured resin. Examples of the sealing member include metals such as stainless steel, aluminum, and magnesium alloys, polyethylene terephthalate, polycarbonate, polystyrene, nylon, plastics such as polyvinyl chloride, and composites thereof, glass, and the like. In the case of a resin film, a laminate of gas barrier layers such as aluminum, aluminum oxide, silicon oxide, and silicon nitride can be used as in the case of a resin substrate. The gas barrier layer can be formed by sputtering, vapor deposition or the like on both surfaces or one surface of the sealing member before molding the sealing member, or may be formed on both surfaces or one surface of the sealing member after sealing by a similar method. . Also in this case, the oxygen permeability is 1 × 10 ⁻³ ml / (m ² · 24 h · atm) or less, the water vapor permeability (25 ± 0.5 ° C., relative humidity (90 ± 2)% RH) is 1 × It is preferably 10 ⁻³ g / (m ² · 24 h) or less.

The sealing member may be a film laminated with a metal foil such as aluminum. As a method for laminating the polymer film on one side of the metal foil, a generally used laminating machine can be used. As the adhesive, polyurethane-based, polyester-based, epoxy-based, acrylic-based adhesives and the like can be used. You may use a hardening | curing agent together as needed. A hot melt lamination method, an extrusion lamination method and a coextrusion lamination method can also be used, but a dry lamination method is preferred.

In addition, when the metal foil is formed by sputtering or vapor deposition, and is formed from a fluid electrode material such as a conductive paste, the metal foil may be formed by using a polymer film as a substrate. .

《Protective film, protective plate》
In order to increase the mechanical strength of the organic EL element, a protective film or a protective plate may be provided outside the sealing film on the side facing the support substrate with the organic functional layer interposed therebetween or on the outer side of the sealing film. In particular, when sealing is performed with a sealing film, the mechanical strength is not necessarily high, and thus it is preferable to provide such a protective film and a protective plate. As a material that can be used for this, the same glass plate, polymer plate / film, metal plate / film, and the like used for the sealing can be used. However, the polymer film is light and thin. Is preferably used.

In the present invention, it is preferable that the light extraction member is provided between the substrate and the anode or at any location on the light emission side from the substrate.

Examples of the light extraction member include a prism sheet, a lens sheet, and a diffusion sheet. Further, a diffraction grating or a diffusion structure introduced into an interface or any medium that causes total reflection can be used.

Usually, in an organic electroluminescence element that emits light from a substrate, a part of the light emitted from the light emitting layer causes total reflection at the interface between the substrate and air, causing a problem of loss of light. In order to solve this problem, prismatic or lens-like processing is applied to the surface of the substrate, or prism sheets, lens sheets, and diffusion sheets are affixed to the surface of the substrate, thereby suppressing total reflection and light extraction efficiency. To improve.

Also, in order to increase the light extraction efficiency, a method of introducing a diffraction grating or a method of introducing a diffusion structure in an interface or any medium that causes total reflection is known.

<Application>
The organic EL element according to the present invention can be used as a display device, a display, and various light sources.

Examples of light sources include home lighting, interior lighting, clock and liquid crystal backlights, billboard advertisements, traffic lights, light sources for optical storage media, light sources for electrophotographic copying machines, light sources for optical communication processors, and light sources for optical sensors. Furthermore, it can be used in a wide range of applications such as general household appliances that require a display device, but it can be used effectively as a backlight for a liquid crystal display device combined with a color filter, and as a light source for illumination. it can.

In the organic EL device according to the present invention, patterning may be performed by a metal mask, an inkjet printing method, or the like at the time of film formation, if necessary. In the case of patterning, only the electrode may be patterned, the electrode and the light emitting layer may be patterned, or the entire layer of the organic EL element may be patterned. The method can be used.

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited thereto. In addition, although the display of "part" or "%" is used in an Example, unless otherwise indicated, "part by mass" or "mass%" is represented.

Example 1
<< Production of organic EL element >>
[Preparation of Organic EL Element 101: Formation of Organic Functional Layer by Vacuum Deposition Method]
(Formation of anode)
After patterning on a glass substrate (NH techno glass, NA45) in which ITO (indium tin oxide) was formed into a film with a thickness of 150 nm on a glass substrate having a thickness of 150 mm × 150 mm and a thickness of 1.1 mm, The substrate provided with the ITO transparent electrode was subjected to ultrasonic cleaning with isopropyl alcohol, dried with dry nitrogen gas, and UV ozone cleaning was performed for 5 minutes.

(Formation of organic functional layer)
Next, the glass substrate having the ITO transparent electrode was fixed to a substrate holder in a plasma processing chamber connected to a commercially available vacuum deposition apparatus. In addition, each of the vapor deposition crucibles in the vacuum vapor deposition apparatus was filled with an optimum amount of the constituent material of each layer for producing the organic EL element. The evaporation crucible used was made of a resistance heating material made of molybdenum or tungsten.

After performing a plasma treatment for 2 minutes at an oxygen pressure of 1 Pa and an electric power of 100 W (electrode area: about 450 cm ² ), the substrate is transferred to each vapor deposition chamber of the organic EL constituent layer without being exposed to the atmosphere. Film formation was performed.

First, after depressurizing to a vacuum of 1 × 10 ⁻⁴ Pa, the deposition crucible containing m-MTDATA was energized and heated, and deposited on a transparent support substrate at a deposition rate of 0.1 nm / sec. A hole injection layer was provided. Next, α-NPD was deposited in the same manner to provide a 30 nm hole transport layer.

Next, each light emitting layer was formed according to the following procedure.

Compounds D-1, D-2 and CBP were co-deposited at a deposition rate of 0.1 nm / second so that the concentration of D-1 was 14% by mass and D-2 was 1.8% by mass. A yellow phosphorescent light emitting layer having a thickness of 622 nm and a thickness of 6 nm was formed. Next, compounds D-3 and H-1 were co-evaporated at a deposition rate of 0.1 nm / second so that D-3 was at a concentration of 9% by mass, and a blue phosphorescence having an emission maximum wavelength of 470 nm and a thickness of 20 nm. A light emitting layer was formed.

Thereafter, Compound M-1 was deposited to a thickness of 50 nm to form a layer having hole blocking and electron transport functions, and LiF was deposited to a thickness of 1 nm to form an electron transport layer.

Furthermore, aluminum was vapor-deposited with a thickness of 110 nm to form a cathode, and an organic EL element 101 was produced.

[Preparation of Organic EL Element 102: Formation of Organic Functional Layer by Batch Method]
The organic EL element 102 was produced according to the batch production method organic functional layer production line shown in FIG.

FIG. 11 is a schematic diagram showing an example of a production line for forming an organic functional layer by a batch method as a comparative example.

In FIG. 11 a), for example, positioning pins 202 for determining the installation position of the substrate P on which the anode 203 is formed are provided on the holding member 201 at four locations. Then, the substrate P on which the anode 203 is formed is carried in.

Next, as shown in FIG. 11 b, the substrate P placed on the holding member 201 is suction-fixed.

Next, as c) of FIG. 11, a first organic functional layer L1 (for example, a hole injection layer) is formed on the anode 203 using a slit type die coater Co having the configuration shown in FIG. Thereafter, as shown in FIG. 11 d), the drying unit H performs drying by blowing heated hot air 204 onto the formed first organic functional layer L <b> 1.

Next, as shown in e) and f) of FIG. 11, the substrate P placed on the holding member 201 is removed and removed to form the first organic functional layer, and the processes a) to f) are sequentially performed. Repeatedly, an organic functional layer group was formed.

(Formation of anode)
This ITO transparent electrode was formed by patterning a substrate (NH technoglass NA45) in which ITO (indium tin oxide) was formed as a positive electrode 203 on a glass substrate P of 150 mm × 150 mm × 1.1 mm with a thickness of 150 nm. A substrate P (also referred to as an ITO substrate) provided with (anode 203) was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes.

(Formation of hole injection layer)
Next, the substrate P on which the ITO transparent electrode is formed as the anode 203 is loaded and mounted on the substrate P on which the anode 203 is formed in accordance with the positioning pins 202 on the holding member 201 as shown in FIGS. did.

As shown in FIG. 11 c), poly (3,4-ethylenedioxythiophene) -polystyrene sulfonate (PEDOT / PSS, manufactured by Bayer, Baytron P Al 4083) is purified on the anode 203 of the mounted substrate P. Using a slit type die coater Co, the hole injection layer coating solution 1 diluted to 70% with water was set at a coating speed of 3 m / min, and the temperature during coating of the hole injection layer forming coating solution was set to 25 ° C. After coating under the condition that the thickness of the hole injection layer L1 after drying is 30 nm, as shown in FIG. 11 d), drying is performed by spraying heated hot air 204 at 120 ° C. for 30 minutes from the drying section H. did. Next, desorption and transportation were performed according to the procedures shown in e) and f) of FIG. 11 to provide a hole injection layer having a thickness of 30 nm.

(Formation of hole transport layer)
Next, a hole transport layer was formed on the hole injection layer in a batch manner on the substrate P on which the hole injection layer had been formed, by the processes shown in FIGS.

Specifically, the substrate P on which the hole injection layer is formed is transferred to an atmosphere of nitrogen gas (grade G1), and an HT-1 compound (Mw = 80,000), which is a hole transport material, is added to chlorobenzene by 0.5. % Of the hole-transporting layer coating solution 1 dissolved at a coating rate of 3 m / min using a slit-type die coater Co, and the temperature during coating of the coating solution for forming a hole-transporting layer was set to 25 ° C. The hole transport layer L2 is applied under the condition that the film thickness is 30 nm to form a hole transport layer with a film thickness of 30 nm, and heated hot air 204 at 120 ° C. is applied for 30 minutes from the drying section H shown in FIG. The hole transport layer was formed by spraying and drying.

(Formation of light emitting layer)
Next, on the substrate P on which the hole transport layer was formed, a light emitting layer was formed in a batch manner on the hole transport layer by the processes shown in FIGS.

Specifically, the light emitting layer coating solution 1 having the following composition was formed in the same manner as described above to form a light emitting layer having a thickness of 40 nm. Film formation was performed in an atmosphere of nitrogen gas (oxygen concentration 250 ppm, moisture concentration 250 ppm), and then dried by blowing hot air 204 at 120 ° C. for 30 minutes from the drying section H shown in d) of FIG. A light emitting layer was formed.

<Light emitting layer coating solution 1>
Host compound (HA) 14.15 parts by weight Blue dopant (D-66) 2.45 parts by weight Green dopant (D-67) 0.025 parts by weight Red dopant (D-80) 0.025 parts by weight Toluene 2 1,000 parts by mass

 

(Formation of electron transport layer)
Next, on the substrate P on which the light emitting layer was formed, an electron transport layer was formed in a batch manner on the light emitting layer by the processes shown in FIGS.

Specifically, an electron transport layer coating solution 1 prepared by dissolving 20 mg of the following compound A in 4 ml of tetrafluoropropanol (TFPO) was formed in the same manner as described above, and then d) in FIG. From the drying section H shown in FIG. 5, heated hot air 204 at 120 ° C. was blown for 30 minutes to dry, thereby forming an electron transport layer having a thickness of 30 nm. Film formation was carried out in an atmosphere of nitrogen gas (oxygen concentration 250 ppm, moisture concentration 250 ppm).

 

 

(Formation of electron injection layer and cathode)
Subsequently, the sample in which the electron injection layer, the electron transport layer, the light emitting layer, and the electron transport layer were formed on the substrate P was attached to a vacuum deposition apparatus without being exposed to the atmosphere. In addition, a molybdenum resistance heating boat containing sodium fluoride and potassium fluoride is attached to a vacuum deposition apparatus, and the vacuum chamber is depressurized to 4 × 10 ⁻⁵ Pa, and then the molybdenum resistance heating boat is energized. Heating is performed to form a thin film having a thickness of 1 nm on the electron transport layer at a rate of 0.02 nm / second with sodium fluoride. An electron injection layer having a 5 nm thin film was prepared. Subsequently, 100 nm of aluminum was vapor-deposited to form a cathode, and an organic EL element 102 was produced.

[Production of Organic EL Element 103: Formation of Organic Functional Layer by Roll-to-Roll Method]
An organic EL element 103 as a comparative example was produced according to the organic functional layer production line by the roll-to-roll method shown in FIG.

The roll-to-roll organic functional layer production line shown in FIG. 12 is a first film-forming step Stage 1 in which a substrate laminated roll 501 having an anode or the like is fed out from an unwinder section and passed through a dancer roll section 506. In the coating step 503, a first organic functional layer, for example, an electron injection layer is formed on the substrate 502 that is continuously transported while being held by the back roll 505 using a die coater Co that is a coating unit. After drying using the transport means H in the drying step 504, the organic functional layer is similarly applied and dried to form a film in Stage 2 as the next step. The substrate 502 on which the organic functional layer group has been formed through Stages 3 and 4 is laminated as a lamination roll 507 in the winder unit through the dancer roll 506.

(Preparation of strip substrate)
A polyethylene terephthalate film (Teijin-DuPont film, hereinafter abbreviated as PET) having a thickness of 100 μm, a width of 200 mm, and a length of 500 m was prepared.

(Formation of anode)
The alignment mark attached to the prepared PET is detected, and according to the position of the alignment mark, a 120 nm thick ITO (indium tin oxide) is sputtered on the PET under a vacuum environment condition of 5 × 10 ⁻¹ Pa on the mask. A pattern was formed, and 12 mm × 5 mm anodes having take-out electrodes were continuously formed in 12 rows at regular intervals, and temporarily wound up and stored.

(Formation of hole injection layer)
Next, a hole injection layer was formed in Stage 1 according to the organic functional layer production line by the roll-to-roll method shown in FIG.

The substrate 502 formed up to the anode is fed out from the unwinder section, and the hole injection layer coating used in the fabrication of the organic EL element 102 is applied in Stage 1 by using the slit type die coater Co shown in FIG. The liquid 1 is applied onto the substrate 502 held by the back roll 505, the coating speed is 5 m / min, the coating width is 180 mm, the coater gap is 200 μm with respect to the wet film thickness, and the temperature at the time of coating the hole injection layer forming coating liquid is 25 ° C. Then, in a drying step 504, a hot injection air of 120 ° C. was blown to form a hole injection layer having a thickness of 30 nm.

(Formation of hole transport layer)
Subsequently, in the same manner as described above, a hole transport layer having a thickness of 30 nm was formed in Stage 2 using the hole transport layer coating solution 1 used for the production of the organic EL element 102.

(Formation of light emitting layer)
Next, in the same manner as described above, a light emitting layer having a film thickness of 40 nm was formed in Stage 3 using the light emitting layer coating liquid 1 used for the production of the organic EL element 102.

(Formation of electron transport layer)
Next, in the same manner as described above, in Stage 4, using the electron transport layer coating solution 1 used for the production of the organic EL element 102, an electron transport layer having a film thickness of 30 nm is formed, and as an unwinder part, a laminated roll 507 is formed. Winded up.

(Formation of electron injection layer and cathode)
Then, after cutting the sample which formed the electron injection layer, the electron carrying layer, the light emitting layer, and the electron carrying layer on the board | substrate P to the predetermined size, it attached to the vacuum evaporation system, without exposing to air | atmosphere. In addition, a molybdenum resistance heating boat containing sodium fluoride and potassium fluoride is attached to a vacuum deposition apparatus, and the vacuum chamber is depressurized to 4 × 10 ⁻⁵ Pa, and then the molybdenum resistance heating boat is energized. Heating is performed to form a thin film having a thickness of 1 nm on the electron transport layer at a rate of 0.02 nm / second with sodium fluoride. An electron injection layer having a 5 nm thin film was prepared. Subsequently, 100 nm of aluminum was vapor-deposited to form a cathode, and an organic EL element 103 was produced.

[Production of Organic EL Element 104: Formation of Organic Functional Layer by In-line Method 1]
The organic EL element 104 according to the present invention was fabricated according to the organic functional layer production line by the in-line method shown in FIG.

(Formation of anode)
After patterning on a substrate (NH technoglass NA45) in which ITO (indium tin oxide) was formed as a positive electrode on a glass substrate P of 150 mm × 150 mm × 1.1 mm in thickness of 150 nm, this ITO transparent electrode ( A substrate P (also referred to as an ITO substrate) provided with an anode) was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes.

(Formation of hole injection layer)
Next, the substrate P on which the ITO transparent electrode is formed as the anode is placed on the substrate holding belt 32 that is continuously conveyed, and in the Stage 1 shown in FIG. 2, a slit type die coater Co1 having the configuration shown in FIG. 3 is used. Using the hole injection layer coating liquid 1 used in the preparation of the organic EL element 102, the coating speed was set to 3 m / min, the temperature at the time of coating the hole injection layer forming coating liquid was set to 25 ° C. The hole injection layer L1 was applied under the condition that the film thickness was 30 nm, and then heated hot air at 120 ° C. was blown in the drying unit H1 disposed downstream to form the hole injection layer L1.

In addition, formation of the positive hole injection layer L1 in the 1st film forming environment 30 (area 1) was performed in the atmosphere 31 of oxygen concentration 300ppm and water concentration 300ppm using nitrogen gas as an inert gas.

(Formation of hole transport layer)
Next, the substrate P on which the hole injection layer L1 is formed is transferred to the Stage 2 shown in FIG. 2, and the holes used in the production of the organic EL element 102 using the slit type die coater Co2 having the configuration shown in FIG. Conditions in which the transport layer coating liquid 1 is used, the coating speed is 3 m / min, the temperature at the time of coating the hole transport layer forming coating liquid is set to 25 ° C., and the thickness of the hole transport layer L2 after drying is 30 nm. Then, a heated hot air of 120 ° C. was blown in the drying unit H2 disposed downstream to form the hole transport layer L2.

In addition, formation of the positive hole transport layer L2 in the 1st film forming environment 30 (area 1) was performed in the atmosphere 31 of oxygen concentration 300ppm and water concentration 300ppm using nitrogen gas as an inert gas.

(Formation of light emitting layer)
Next, the substrate P on which the hole transport layer L2 is formed is transferred to the Stage 3 shown in FIG. 2, and the light emitting layer used in the production of the organic EL element 102 using the slit type die coater Co3 having the configuration shown in FIG. Using the coating liquid 1, the coating speed was set to 3 m / min, the temperature at the time of coating the coating liquid for forming the light emitting layer was set to 25 ° C., and the coating was performed under the condition that the thickness of the light emitting layer L3 after drying was 30 nm. Heating hot air of 120 ° C. was blown at the drying unit H3 disposed downstream to form the light emitting layer L3.

The formation of the light emitting layer L3 in the first film forming environment 30 (area 1) was performed in an atmosphere 31 with an oxygen concentration of 300 ppm and a moisture concentration of 300 ppm using nitrogen gas as an inert gas.

(Formation of electron transport layer)
Next, the substrate P on which the light emitting layer L3 is formed is transferred to the Stage 4 shown in FIG. 2, and the electron transport layer coating used in the production of the organic EL element 102 is performed using the slit type die coater Co4 having the configuration shown in FIG. Using the liquid 1, the coating speed was 3 m / min, the temperature at the time of coating the coating liquid for forming the electron transport layer was set to 25 ° C., and the coating was performed under the condition that the thickness of the electron transport layer L4 after drying was 30 nm. Then, a heated hot air of 120 ° C. was blown at the drying unit H4 disposed downstream to form the electron transport layer L4.

The formation of the electron transport layer L4 in the first film-forming environment 30 (area 1) was performed in an atmosphere 31 having an oxygen concentration of 300 ppm and a water concentration of 300 ppm using nitrogen gas as an inert gas.

(Bake process)
Subsequently, the sample on which the electron injection layer, the electron transport layer, the light emitting layer, and the electron transport layer are formed on the substrate P is removed from the substrate holding belt 32 that is continuously transported, moved to the second film forming environment 40, and heated. Baking treatment was performed by blowing hot air of 120 ° C. for 60 minutes from part H5.

The second film-forming environment 40 (area 2) during the baking treatment was performed in an atmosphere 41 using nitrogen gas as an inert gas and having an oxygen concentration of 90 ppm and a water concentration of 90 ppm.

(Formation of electron injection layer and cathode)
Subsequently, the substrate P formed up to the baked electron injection layer, electron transport layer, light emitting layer, and electron transport layer was attached to a vacuum deposition apparatus without being exposed to the atmosphere.

A molybdenum resistance heating boat in a vacuum vapor deposition apparatus containing sodium fluoride and potassium fluoride is attached to the vacuum vapor deposition apparatus, and the vacuum chamber is depressurized to 4 × 10 ⁻⁵ Pa. Heated by energization to form a thin film with a thickness of 1 nm on the electron transport layer at a rate of 0.02 nm / second with sodium fluoride, and then similarly form a film with potassium fluoride at a rate of 0.02 nm / second on the sodium fluoride. A 1.5 nm thick thin film was formed to obtain an electron injection layer. Subsequently, 100 nm of aluminum was vapor-deposited to form a cathode, and an organic EL element 104 was produced.

[Production of Organic EL Element 105: Organic Functional Layer Formation 2 by In-line Method]
In the production of the organic EL element 104, in Stages 1 to 4, drying by the drying parts H1 to H4 is not performed, and only in the baking process step, heating hot air of 120 ° C. is blown from the heating part H5 for 60 minutes. An organic EL element 105 was produced in the same manner except that (drying treatment) was performed.

<< Evaluation of production suitability of organic EL elements >>
[Evaluation of production efficiency]
In the manufacturing method of the organic EL element 104, the time required to manufacture one organic EL element was set to 1.00, the relative time required to manufacture each organic EL element was calculated, and the production efficiency was evaluated according to the following criteria. .

A: Relative time required for producing one organic EL element is less than 0.90. O: Relative time required for producing one organic EL element is 0.90 or more and less than 1.10. A: Relative time required for producing one organic EL element is 1.10 or more and less than 1.50. X: Relative time required for producing one organic EL element is 1.50 or more. [Evaluation of capital investment costs]
The equipment expense applied to production of each organic EL element was calculated by setting the equipment expense applied to production of the organic EL element 104 to 1.00, and the equipment investment cost was evaluated according to the following criteria.

A: Relative investment cost of manufacturing equipment applied to manufacture of organic EL element is less than 0.90 B: Relative investment cost of manufacturing equipment applied to manufacture of organic EL element is 0.90 or more, 1.10 Δ: The relative investment cost of the manufacturing equipment applied to the production of the organic EL element is 1.10 or more and less than 1.50 ×: The relative investment cost of the production equipment applied to the production of the organic EL element is 1.50 or more << Quality evaluation of organic EL element >>
[Measurement of quantum efficiency]
For each organic EL element, the external extraction quantum efficiency when applying a constant current of ^2.5 mA / cm ^{2 in} a dry nitrogen gas atmosphere at 23 ° C. using a spectral radiance meter CS-1000 (manufactured by Konica Minolta Sensing) %). The quantum efficiency was expressed as a relative value with the quantum efficiency of the organic EL element 104 as 100. It represents that it is excellent in external extraction quantum efficiency, so that a numerical value is large.

[Measurement of luminous lifetime]
A current that gives a front luminance of 1000 cd / m ² was applied to each of the produced organic EL elements, and the organic EL elements were continuously driven. The time required for the front luminance to reach the initial half value (500 cd / m ² ) (light emission lifetime) was determined. For the measurement, a spectral radiance meter CS-1000 (manufactured by Konica Minolta Sensing Co., Ltd.) was used. It represents that it is excellent in the light emission lifetime, so that a numerical value is large.

[Evaluation of luminance unevenness resistance]
The luminance distribution in the light emitting surface when a constant current of ^2.5 mA / cm ² was applied to each of the produced organic EL elements was measured with Prometric (manufactured by Cybernet System). The luminance distribution was expressed as the standard deviation of the luminance within each light emitting surface when the light emitting surface was equally divided into 40. The lower the numerical value, the less the luminance unevenness and the better the luminance unevenness resistance.

Table 1 shows the results obtained as described above.

 

 

As is apparent from the results shown in Table 1, the organic EL device manufacturing method defined in the present invention is an organic device that can achieve both production efficiency and capital investment cost compared to conventional manufacturing methods. It can be seen that the EL element is excellent in quantum efficiency, light emission lifetime and luminance unevenness resistance.

Example 2
<< Preparation of organic EL elements 201 to 203 >>
In the organic EL element 104 described in Example 1 (application speed in the first film-forming environment 30 (area 1): 3 m / min), the application speed in the first film-forming environment 30 (area 1) is 5 m. Organic EL elements 201 to 203 were produced in the same manner except for changing to 10 / min, 10 m / min, and 15 m / min.

<< Production suitability and quality evaluation of organic EL elements >>
For the organic EL elements 201 to 203 produced above and the organic EL element 104 produced in Example 1, the production efficiency, quantum efficiency, light emission lifetime, and luminance unevenness resistance were evaluated in the same manner as in Example 1. The results obtained are shown in Table 2.

 

 

By making the coating speed of the first film-forming environment 30 (area 1) in the manufacture of the organic EL element 5 m / min or more, the production efficiency can be improved without impairing the properties such as quantum efficiency, light emission lifetime and luminance unevenness resistance. Can be increased.

Example 3
<< Production of organic EL elements 301 to 309 >>
Organic EL element 105 described in Example 1 (first film forming environment (area 1): using nitrogen gas as an inert gas, in an atmosphere having an oxygen concentration of 300 ppm and a water concentration of 300 ppm. Second film forming environment (area 2): Using nitrogen gas as an inert gas, in an atmosphere having an oxygen concentration of 90 ppm and a moisture concentration of 90 ppm), the atmosphere composition in the first film-forming environment (area 1) and the second film-forming environment (area 2) Organic EL elements 301 to 309 were fabricated in the same manner except that the atmospheric composition was changed to the conditions shown in Table 3, respectively.

<< Quality evaluation of organic EL elements >>
For the organic EL elements 301 to 309 prepared above and the organic EL element 105 manufactured in Example 1, the production cost was evaluated by the following method, and the quantum efficiency, the light emission lifetime, and the Evaluation of luminance unevenness resistance was performed, and the obtained results are shown in Table 3.

〔Production cost〕
In the production of the organic EL element 105, the cost required for forming the organic functional layer was set to 1.00, and the relative production cost was evaluated according to the following criteria.

A: The relative production cost of the organic EL element is 1.05 or more. O: The relative production cost of the organic EL element is 0.95 or more and less than 1.05. Δ: The relative production cost of the organic EL element is 0.90 or more and less than 0.95 ×: The relative production cost of the organic EL element is less than 0.90

 

 

In the organic EL manufacturing method of the present invention, the concentration of gas components other than the inert gas in the first film-forming environment (area 1) is 500 ppm or more, and other than the inert gas in the second film-forming environment (area 2) It can be seen that by making the gas component concentration of 200 ppm or less, the production cost is excellent and the quantum efficiency, the light emission lifetime, and the luminance unevenness resistance are further improved.

Example 4
<< Preparation of organic EL elements 401 to 408 >>
In the organic EL element 105 described in Example 1 (glass substrate, baking condition in second film forming environment (area 2): 120 ° C., 60 minutes), the type of the substrate (resin substrate: polyethylene terephthalate film having a thickness of 100 μm) , Glass substrate: made of NH technoglass with a thickness of 1.1 mm, NA45) and the same conditions except that the baking conditions in the second film-forming environment (area 2) were changed to the conditions shown in Table 4, respectively. EL elements 401 to 408 were produced.

<< Quality evaluation of organic EL elements >>
For the organic EL elements 401 to 408 prepared above and the organic EL element 105 manufactured in Example 1, the production efficiency, quantum efficiency, light emission lifetime, and luminance unevenness resistance were evaluated in the same manner as the method described in Example 1. The results obtained are shown in Table 4.

 

 

In the organic EL manufacturing method of the present invention, by using a glass substrate as a substrate, the production efficiency is higher than that of an organic EL element using a resin substrate, and the baking time in the second film-forming environment (area 2). It can be seen that even if the length is shortened, the performance degradation is small. This is because the glass substrate has less penetration of the solvent or the like constituting each coating liquid into the substrate when the organic functional layer is applied, and as a result, the glass substrate is desired even in a short time. It is speculated that the characteristics of

Example 5
[Production of Organic EL Element 502]
In the production line of the organic functional layer by the in-line method shown in FIG. 4, the substrate was not lifted by the substrate floating portion 55, but was directly placed on the substrate holding member and applied to produce the organic EL element 502. .

(Applying alignment marks)
Alignment marks were given to the four corners of a glass substrate P of 150 mm × 150 mm × 1.1 mm.

The alignment marks were formed by forming a cross mark with an ITO (indium tin oxide) film having a thickness of 120 nm at the four corners on the glass substrate P under a vacuum environment condition of 5 × 10 ⁻¹ Pa by a sputtering method.

(Formation of anode)
After patterning on a substrate (NH technoglass NA45) in which ITO (indium tin oxide) was formed as a positive electrode on a glass substrate P of 150 mm × 150 mm × 1.1 mm in thickness of 150 nm, this ITO transparent electrode ( A substrate P (also referred to as an ITO substrate) provided with an anode) was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes.

(Formation of hole injection layer)
Next, the substrate P on which the ITO transparent electrode is formed as the anode is placed on the substrate holding member 32 that is continuously transported, and in the Stage 1 shown in FIG. 4, a slit type die coater Co1 having the configuration shown in FIG. 6 is used. The alignment mark is detected by a CCD camera, and according to the information, the hole injection layer coating solution 1 used in the production of the organic EL element 102 on the substrate P is applied at a coating speed of 3 m / min, with a coating speed of 3 m / min. The temperature at the time of application | coating of the coating liquid for hole injection layer formation is set to 25 degreeC, it apply | coats on the conditions that the film thickness of the hole injection layer L1 after drying is set to 30 nm, and then the drying part H1 arrange | positioned downstream The hole injection layer L1 was formed by spraying 120 ° C. hot air.

In addition, formation of the positive hole injection layer L1 in the 1st film forming environment 30 (area 1) was performed in the atmosphere 31 of oxygen concentration 300ppm and water concentration 300ppm using nitrogen gas as an inert gas.

(Formation of hole transport layer)
Next, the substrate P on which the hole injection layer L1 is formed is transferred to the Stage 2 shown in FIG. 4, and the holes used in the production of the organic EL element 102 are made using the slit type die coater Co2 having the configuration shown in FIG. Using the transport layer coating liquid 1, according to the detection information of the alignment mark by the CCD camera, set the coating speed to 3 m / min, and the temperature during coating of the hole transport layer forming coating liquid to 25 ° C. without floating the substrate at all. The hole transport layer L2 after drying is applied under the condition that the film thickness is 30 nm, and then heated hot air at 120 ° C. is blown in the drying unit H2 disposed downstream to form the hole transport layer L2. did.

In addition, formation of the positive hole transport layer L2 in the 1st film forming environment 30 (area 1) was performed in the atmosphere 31 of oxygen concentration 300ppm and water concentration 300ppm using nitrogen gas as an inert gas.

(Formation of light emitting layer)
Next, the substrate P on which the hole transport layer L2 is formed is transferred to the Stage 3 shown in FIG. 4, and the light emitting layer used in the production of the organic EL element 102 using the slit type die coater Co3 having the configuration shown in FIG. Using the coating solution 1, according to the alignment mark detection information by the CCD camera, the substrate is not lifted at all, the substrate is not lifted at all, the coating speed is 3 m / min, and the temperature at the time of coating the coating solution for forming the light emitting layer is 25 ° C. The light emitting layer L3 after drying was coated under the condition that the film thickness was 30 nm, and then heated warm air at 120 ° C. was blown in the drying unit H3 disposed downstream to form the light emitting layer L3. .

The formation of the light emitting layer L3 in the first film forming environment 30 (area 1) was performed in an atmosphere 31 having an oxygen concentration of 300 ppm and a water concentration of 300 ppm using nitrogen gas as an inert gas.

(Formation of electron transport layer)
Next, the substrate P on which the light emitting layer L3 is formed is transferred to the Stage 4 shown in FIG. 4, and the slit-type die coater Co4 having the configuration shown in FIG. 6 is used to apply the electron transport layer used in the production of the organic EL element 102. Using liquid 1, according to the alignment mark detection information from the CCD camera, the substrate was not lifted at all, the coating speed was set to 3 m / min, and the temperature at the time of coating the coating liquid for forming the electron transport layer was set to 25 ° C. The electron transport layer L4 was applied under the condition that the film thickness was 30 nm, and then heated warm air of 120 ° C. was blown at the drying unit H4 disposed downstream to form the electron transport layer L4.

The formation of the electron transport layer L4 in the first film-forming environment 30 (area 1) was performed in an atmosphere 31 having an oxygen concentration of 300 ppm and a water concentration of 300 ppm using nitrogen gas as an inert gas.

(Bake process)
Subsequently, the sample in which the electron injection layer, the electron transport layer, the light emitting layer, and the electron transport layer are formed on the substrate P is removed from the substrate holding member 32 that is continuously transported, moved to the second film forming environment 40, and heated. Baking treatment was performed by blowing hot air of 120 ° C. for 60 minutes from part H5.

The second film-forming environment 40 (area 2) during the baking treatment was performed in an atmosphere 41 using nitrogen gas as an inert gas and having an oxygen concentration of 90 ppm and a water concentration of 90 ppm.

(Formation of electron injection layer and cathode)
Subsequently, the substrate P formed up to the baked electron injection layer, electron transport layer, light emitting layer, and electron transport layer was attached to a vacuum deposition apparatus without being exposed to the atmosphere.

A molybdenum resistance heating boat in a vacuum vapor deposition apparatus containing sodium fluoride and potassium fluoride is attached to the vacuum vapor deposition apparatus, and the vacuum chamber is depressurized to 4 × 10 ⁻⁵ Pa. Heated by energization to form a thin film with a thickness of 1 nm on the electron transport layer at a rate of 0.02 nm / second with sodium fluoride, and then similarly form a film with potassium fluoride at a rate of 0.02 nm / second on the sodium fluoride. A 1.5 nm thick thin film was formed to obtain an electron injection layer. Subsequently, 100 nm of aluminum was deposited to form a cathode, and an organic EL element 502 was produced.

[Production of Organic EL Element 503: Substrate Floating Method]
Using the production line for the organic functional layer by the in-line method shown in FIG. 4, coating was performed while the substrate was lifted by the substrate floating portion having the structure shown in FIG.

(Applying alignment marks)
Alignment marks were given to the four corners of a glass substrate P of 150 mm × 150 mm × 1.1 mm.

The alignment marks were formed by forming a cross mark with an ITO (indium tin oxide) film having a thickness of 120 nm at the four corners on the glass substrate P under a vacuum environment condition of 5 × 10 ⁻¹ Pa by a sputtering method.

(Formation of anode)
After patterning on a substrate (NH technoglass NA45) in which ITO (indium tin oxide) was formed as a positive electrode on a glass substrate P of 150 mm × 150 mm × 1.1 mm in thickness of 150 nm, this ITO transparent electrode ( A substrate P (also referred to as an ITO substrate) provided with an anode) was ultrasonically cleaned with isopropyl alcohol, dried with dry nitrogen gas, and subjected to UV ozone cleaning for 5 minutes.

(Formation of hole injection layer)
Next, the substrate P on which the ITO transparent electrode is formed as the anode is placed on the substrate holding member 32 that is continuously transported, and in the Stage 1 shown in FIG. 4, a slit type die coater Co1 having the configuration shown in FIG. 6 is used. The alignment mark was detected by the CCD camera, and the substrate P was floated by the substrate floating portion shown in FIG. 7 according to the obtained positional information of the substrate. In the levitation method, two compressed gas supply units 300A and 300B were supplied with compressed gas having an inert gas of nitrogen gas, an oxygen concentration of 300 ppm, and a moisture concentration of 300 ppm by gas blow pumps 304A and 304B. On the other hand, the vacuum pump 305 was operated to take in air from the decompression unit 306.

Next, the flying height H1 of the substrate P with respect to the substrate holding member 32 is controlled to 150 μm by the position detection sensor 307, and the height H2 (bead gap) between the lip at the tip of the coating coater Co and the surface of the substrate P is 300 μm. Furthermore, the amount of compressed gas blown and the amount of intake air were controlled by the decompression unit 306.

Under the above conditions, the hole injection layer coating liquid 1 used in the production of the organic EL element 102 on the substrate P was applied at a coating speed of 3 m / min, and the temperature during coating of the hole injection layer forming coating liquid was 25 ° C. Set and apply under the condition that the film thickness of the hole injection layer L1 after drying is 30 nm, and then spray heated hot air at 120 ° C. in the drying unit H1 disposed downstream, and the hole injection layer L1 Formed.

In addition, formation of the positive hole injection layer L1 in the 1st film forming environment 30 (area 1) was performed in the atmosphere 31 of oxygen concentration 300ppm and water concentration 300ppm using nitrogen gas as an inert gas.

(Formation of hole transport layer)
Next, the substrate P on which the hole injection layer L1 is formed is transferred to the Stage 2 shown in FIG. 4, and the holes used in the production of the organic EL element 102 are made using the slit type die coater Co2 having the configuration shown in FIG. Using the transport layer coating solution 1, the substrate was floated at a height of 150 μm in the same manner as the floating condition of the hole injection layer, while applying a coating speed of 3 m / min at the time of coating the hole transport layer forming coating solution. The temperature was set to 25 ° C., and the coating was performed under the condition that the film thickness of the hole transport layer L2 after drying was 30 nm, and then heated hot air of 120 ° C. was blown at the drying unit H2 disposed downstream, A hole transport layer L2 was formed.

In addition, formation of the positive hole transport layer L2 in the 1st film forming environment 30 (area 1) was performed in the atmosphere 31 of oxygen concentration 300ppm and water concentration 300ppm using nitrogen gas as an inert gas.

(Formation of light emitting layer)
Next, the substrate P on which the hole transport layer L2 is formed is transferred to the Stage 3 shown in FIG. 4, and the light emitting layer used in the production of the organic EL element 102 using the slit type die coater Co3 having the configuration shown in FIG. In the same manner as the above-described floating condition of the hole injection layer using the coating liquid 1, while the substrate was floated at a height of 150 μm, the coating speed was 3 m / min, and the temperature at the time of coating the light emitting layer forming coating liquid was 25 ° C. The light emitting layer L3 after drying was coated under the condition that the film thickness was 30 nm, and then heated warm air at 120 ° C. was blown in the drying unit H3 disposed downstream to form the light emitting layer L3. .

The formation of the light emitting layer L3 in the first film forming environment 30 (area 1) was performed in an atmosphere 31 with an oxygen concentration of 300 ppm and a moisture concentration of 300 ppm using nitrogen gas as an inert gas.

(Formation of electron transport layer)
Next, the substrate P on which the light emitting layer L3 is formed is transferred to the Stage 4 shown in FIG. 4, and the slit-type die coater Co4 having the configuration shown in FIG. 6 is used to apply the electron transport layer used in the production of the organic EL element 102. In the same manner as in the floating condition of the hole injection layer using the liquid 1, while the substrate was floated at a height of 150 μm, the coating speed was 3 m / min, and the temperature at the time of coating the coating liquid for forming the electron transport layer was 25 ° C. The electron transport layer L4 after drying is applied under the condition that the film thickness is 30 nm, and then heated warm air of 120 ° C. is blown in the drying unit H4 disposed downstream to thereby form the electron transport layer L4. Formed.

The formation of the electron transport layer L4 in the first film-forming environment 30 (area 1) was performed in an atmosphere 31 having an oxygen concentration of 300 ppm and a water concentration of 300 ppm using nitrogen gas as an inert gas.

(Bake process)
Subsequently, the sample in which the electron injection layer, the electron transport layer, the light emitting layer, and the electron transport layer are formed on the substrate P is removed from the substrate holding member 32 that is continuously transported, moved to the second film forming environment 40, and heated. Baking treatment was performed by blowing hot air of 120 ° C. for 60 minutes from part H5.

The second film-forming environment 40 (area 2) during the baking treatment was performed in an atmosphere 41 using nitrogen gas as an inert gas and having an oxygen concentration of 90 ppm and a water concentration of 90 ppm.

(Formation of electron injection layer and cathode)
Subsequently, the substrate P formed up to the baked electron injection layer, electron transport layer, light emitting layer, and electron transport layer was attached to a vacuum deposition apparatus without being exposed to the atmosphere.

A molybdenum resistance heating boat in a vacuum vapor deposition apparatus containing sodium fluoride and potassium fluoride is attached to the vacuum vapor deposition apparatus, and the vacuum chamber is depressurized to 4 × 10 ⁻⁵ Pa. A current is applied and heated to form a thin film with a thickness of 1 nm on the electron transport layer at a rate of 0.02 nm / second with sodium fluoride, and then similarly with potassium fluoride at a rate of 0.02 nm / second on the sodium fluoride. A 1.5 nm thick thin film was formed to obtain an electron injection layer. Subsequently, 100 nm of aluminum was deposited to form a cathode, and an organic EL element 503 was produced.

[Production of Organic EL Element 504: Substrate Floating Method]
In the production of the organic EL element 503, the same applies except that the in-line organic functional layer production line shown in FIG. 4 is used and the substrate is lifted by the substrate floating portion having the structure shown in FIG. Thus, an organic EL element 504 was produced.

In addition, the floating conditions of the substrate at the time of applying each organic functional layer were the same as those applied to the production of the organic EL element 503.

[Production of Organic EL Element 505: Substrate Floating Method]
In the production of the organic EL element 503, in the process line shown in FIG. 4, at the timing when the feeding of the organic functional layer coating liquid to each coater at the time of coating suspension is stopped in Stage 1 to Stage 4 according to the alignment mark information. An organic EL element 505 was produced in the same manner except that the lip surface of the die coater was wiped using the wiping cleaning apparatus shown in FIGS.

In addition, the constituent solvent of the organic functional layer coating liquid used in each Stage was used as the cleaning liquid in each Stage.

[Production of Organic EL Element 506: Substrate Floating Method]
In the production of the organic EL element 504, in the process line shown in FIG. 4, in the stage 1 to stage 4, according to the alignment mark information, when the organic functional layer coating liquid feeding to each coater at the time of coating suspension is stopped, An organic EL element 506 was produced in the same manner except that the lip surface of the die coater was wiped using the wiping cleaning apparatus shown in FIGS.

In addition, the constituent solvent of the organic functional layer coating liquid used in each Stage was used as the cleaning liquid in each Stage.

[Production of Organic EL Element 507: Substrate Floating Method]
In the production of the organic EL element 505, the organic EL element 507 was produced in the same manner except that the process line shown in FIG. 4 was changed to a process line using an endless transport belt 59 as the substrate holding member shown in FIG. did.

[Production of Organic EL Element 508: Substrate Floating Method]
In the production of the organic EL element 506, the organic EL element 508 was produced in the same manner except that the process line shown in FIG. 4 was changed to a process line using the endless transport belt 59 as the substrate holding member shown in FIG. did.

[Preparation of organic EL element 509: substrate floating system]
In the production of the organic EL element 505, drying by Stages 1 to 4 is not performed, and only in the baking process step, heated hot air of 120 ° C. is blown from the heating unit H5 for 60 minutes to perform baking process (drying process). The organic EL element 509 was produced in the same manner except that the above was applied.

[Production of Organic EL Element 510: Substrate Floating Method]
In the production of the organic EL element 506, drying is not performed by each drying unit of Stages 1 to 4, and only in the baking process step, heated hot air of 120 ° C. is blown from the heating unit H5 for 60 minutes to perform baking process (drying process). The organic EL element 510 was produced in the same manner except that the above was applied.

<< Evaluation of production suitability of organic EL elements >>
[Evaluation of production efficiency]
In the method of manufacturing the organic EL element 503, the time required to manufacture one organic EL element was set to 1.00, the relative time required to manufacture each organic EL element was calculated, and the production efficiency was evaluated according to the following criteria. .

A: Relative time required for producing one organic EL element is less than 0.90. O: Relative time required for producing one organic EL element is 0.90 or more and less than 1.10. A: Relative time required for producing one organic EL element is 1.10 or more and less than 1.50. X: Relative time required for producing one organic EL element is 1.50 or more. << Quality evaluation of organic EL elements >>
[Evaluation of luminance unevenness resistance: Evaluation of film surface uniformity]
The luminance distribution in the light emitting surface when a constant current of ^2.5 mA / cm ² was applied to each of the produced organic EL elements was measured with Prometric (manufactured by Cybernet System). The luminance distribution was expressed as the standard deviation of the luminance within each light emitting surface when the light emitting surface was equally divided into 40. The lower the numerical value, the less the luminance unevenness and the better the luminance unevenness resistance.

[Evaluation of dark spot resistance]
Each organic EL element was stored in an environment of 60 ° C. and 90% RH for 400 hours and 600 hours, and then an enlarged photograph was taken at a magnification of 50 times to confirm the occurrence of dark spots. The dark spot resistance was evaluated according to the standard.

A: Generation of dark spots is not observed even after 600 hours. O: Generation of dark spots is not observed after storage for 400 hours, but slight dark spots are observed after storage for 600 hours. Δ: Storage for 400 hours Later, the generation of minute dark spots is slightly recognized, but the quality is acceptable in practical use. ×: The occurrence of obvious dark spots after storage for 400 hours is observed, and the quality is problematic in practice. The above is a practically usable level.
Table 5 shows the results obtained as described above.

 

 

As is clear from the results shown in Table 5, the organic EL device manufacturing method defined in the present invention is superior in production efficiency to the conventional manufacturing method and excellent in luminance unevenness resistance of the manufactured organic EL device. In addition, it can be seen that the formation of the organic functional layer while being floated and conveyed suppresses the generation of dark spots due to dust and the like.

Example 6
<< Preparation of organic EL elements 601 to 609 >>
Organic EL element 505 described in Example 5 (first film forming environment (area 1): using nitrogen gas as an inert gas, in an atmosphere having an oxygen concentration of 300 ppm and a water concentration of 300 ppm. Second film forming environment (area 2): In the production of nitrogen gas as an inert gas and in an atmosphere having an oxygen concentration of 90 ppm and a moisture concentration of 90 ppm), the atmosphere composition in the first film-forming environment (area 1) and the second film-forming environment (area 2) Organic EL elements 601 to 609 were produced in the same manner except that the atmospheric composition in (1) was changed to the conditions shown in Table 6.

<< Quality evaluation of organic EL elements >>
For the organic EL devices 601 to 609 manufactured as described above and the organic EL device 505 manufactured in Example 5, the luminance unevenness resistance and dark spot resistance were evaluated in the same manner as in the method described in Example 5, and the obtained results Is shown in Table 6.

 

 

In the organic EL manufacturing method of the present invention, the concentration of gas components other than the inert gas in the first film-forming environment (area 1) is 500 ppm or more, and other than the inert gas in the second film-forming environment (area 2) It can be seen that the brightness unevenness resistance and the dark spot resistance are further improved by setting the gas component concentration of 200 ppm or less.

DESCRIPTION OF SYMBOLS 1 Organic EL element 2 Anode 3 Hole injection layer 4 Hole transport layer 5 Light emitting layer 6 Electron transport layer 7 Electron injection layer 8, 203 Cathode 9 Sealing adhesive 20 Organic functional layer group 30 1st film forming environment 32 Substrate Holding member 40 Fourth film forming environment 50 Deposition process 51 Vacuum deposition apparatus 53 Transport roll 54 Support roll 55 Substrate floating unit 56, 301 Substrate floating unit 59 Endless transport belt 103 Lip 107 Coating film 300A, 300B Compressed gas supply unit 302 Chamber 304A, 304B, 304 Gas blow pump 305 Vacuum pump 307 Position detection sensor 311 Compressed gas blow unit 312 Suction unit 401 CCD camera 402 Alignment mark 403 Wiping cleaning device 406 Wipe unit 408 Sheet-like flexible member 409 Wiping member C Slit type die Data Co1 ~ Co4, Co coater H1 ~ H5, H-drying unit L1 ~ L4 organic functional layer P substrate, a support substrate

Claims (17)

A method for producing an organic electroluminescent element, comprising forming an organic electroluminescent film by continuously laminating and coating at least two organic functional layers on a single wafer form substrate by an in-line method by a die coating method. After the organic functional layer of at least two layers is continuously laminated and applied in the first atmosphere (area 1) in which the volume concentration of the gas excluding the inert gas is 500 ppm or more, the volume concentration of the gas excluding the inert gas is The method for producing an organic electroluminescent element according to claim 1, wherein the heat drying treatment is performed in a second atmosphere (area 2) of 200 ppm or less. 3. The method for producing an organic electroluminescent element according to claim 1, wherein the at least two organic functional layers are laminated and applied at a coating speed of 5 m / min or more. The method for manufacturing an organic electroluminescence element according to claim 2 or 3, wherein the inert gas constituting the first atmosphere (area 1) and the second atmosphere (area 2) is nitrogen gas. . The gas excluding the inert gas constituting the first atmosphere (area 1) and the second atmosphere (area 2) is moisture and oxygen gas. The manufacturing method of the organic electroluminescent element of description. The method for manufacturing an organic electroluminescent element according to any one of claims 1 to 5, wherein the single-wafer substrate is a glass substrate. A method for producing an organic electroluminescent element, wherein an organic functional layer laminate is formed by continuously laminating and applying at least two organic functional layers on a single wafer form substrate in an in-line manner using a die coater, comprising: The substrate levitation unit has a gas blowing portion and a gas suction portion, and controls the gas blowing amount and the suction amount to float the substrate while floating the substrate. A method for producing an organic electroluminescent element, characterized in that an organic functional layer laminate is formed by coating with an organic material. 8. The method of manufacturing an organic electroluminescence element according to claim 7, wherein after the organic functional layer is applied on the single-wafer substrate, each has an independent drying zone. The first atmosphere (area 1) for applying the at least two organic functional layers is an atmosphere having a volume concentration of a gas excluding an inert gas of 500 ppm or more. Manufacturing method of organic electroluminescent element. 10. The organic according to claim 7, wherein the levitation gas supplied from the blowing unit of the substrate levitation unit is a gas having a volume concentration of a gas excluding an inert gas of 500 ppm or more. Manufacturing method of electroluminescent element. The organic functional layer laminate in which the at least two organic functional layers are continuously applied by in-line coating using a die coater is heat-dried in a second atmosphere (area 2) in which the volume concentration of gas excluding inert gas is 200 ppm or less. The method for producing an organic electroluminescence element according to claim 7, wherein: The first atmosphere (area 1), the levitation gas supplied from a blowing unit of the substrate levitation unit, and the inert gas constituting the second atmosphere (area 2) are nitrogen gas. The manufacturing method of the organic electroluminescent element of any one of 9-11. The gas excluding the first atmosphere (area 1), the floating gas supplied from the blowing unit of the substrate floating unit and the inert gas constituting the second atmosphere (area 2) is moisture and oxygen gas. The manufacturing method of the organic electroluminescent element of any one of Claims 9-12 characterized by the above-mentioned. 14. The method of manufacturing an organic electroluminescence element according to claim 7, wherein the organic functional layer formed on the single wafer substrate is in a pattern shape. An alignment mark is provided on the single wafer substrate, the alignment mark is detected, and supply and stop of the organic functional layer forming coating liquid from the die coater to the single wafer substrate is controlled. The manufacturing method of the organic electroluminescent element of any one of Claim 7 to 14. The organic electroluminescence device according to any one of claims 7 to 15, wherein a wiping cleaning process is performed on a lip portion of the die coater when the coating liquid for forming an organic functional layer on the die coater is stopped. Production method. The method for manufacturing an organic electroluminescence element according to any one of claims 7 to 16, wherein the single wafer substrate is a glass substrate.

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