JP2019071268A - Organic el display panel manufacturing method and sealing layer forming device - Google Patents

Abstract

To prevent occurrence of problems in a deaeration device in forming a sealing layer of an organic EL display panel by deaerating ink including an organic insulating material such as an ultraviolet-curing resin and applying the ink with use of an ink jet device or the like.SOLUTION: An organic EL display panel manufacturing method includes: a step (S1) of preparing a substrate; steps (S2-S12) of forming a plurality of organic EL elements on the substrate; a step (S13) of forming a first sealing layer on the organic EL elements; and a step (S14) of applying sealing ink having been deaerated by a deaeration device on the first sealing layer thereby to form a second sealing layer, the sealing ink including an ultraviolet-curing resin to which ionic solution is added.SELECTED DRAWING: Figure 10

Description

  The present invention relates to a method of manufacturing an organic EL display panel, and a sealing layer forming apparatus for forming a sealing layer of the organic EL display panel.

In the organic EL display panel, a sealing layer is provided to protect the whole of the plurality of organic EL elements arranged in two dimensions from deterioration due to moisture, gas, and the like.
Conventionally, the sealing layer is formed of silicon nitride (SiN) or the like, and plasma-enhanced chemical vapor deposition (PCVD) is usually used as a formation method. When forming a silicon nitride film, if the film density is increased to improve the sealability, the resistance to bending of the sealing layer becomes extremely small, so that cracking may occur and the coverage may decrease.

Therefore, for example, by forming an organic film on a silicon nitride film, it is conceivable to prevent the decrease in the coverage of the silicon nitride film and to improve the coverage.
By the way, recently, the upsizing of the organic EL display panel has progressed, and an ink (solution) containing a resin material is used as an ink jet apparatus etc. as a method of forming an organic film with high efficiency in such upsizing of the size. A wet process of coating is proposed.

In such an ink jet apparatus, if there is a bubble for some reason in the ink chamber, the pressure generated to eject the ink droplet is absorbed by the bubble, which may cause an ink ejection failure. The As a result, the application amount of the ink dropped onto the substrate may fluctuate, and the organic film may not be formed successfully.
As a cause of generation of air bubbles, for example, the solubility of the dissolved gas in the ink is decreased due to a local pressure decrease or temperature increase, and the supersaturated dissolved gas appears as air bubbles.

In order to avoid the problems as described above, a method has been proposed in which a degassing device for removing the gas contained in the ink is provided, and the degassed ink is supplied to the droplet discharge head and applied (for example, , Patent Document 1).
Recently, a configuration in which a solution is passed through a filter made of a hollow fiber membrane to remove air bubbles and dissolved gas is often used as the degassing device. It is because the degassing apparatus using a hollow fiber membrane can remove dissolved gas efficiently.

Unexamined-Japanese-Patent No. 2003-282246

However, when the hollow fiber membrane type degassing device is used for a certain period, the hollow fiber membrane is damaged, and problems such as ink clogging and ink leakage occur.
The present invention provides a method of manufacturing an organic EL display panel and a device for forming a sealing layer of an organic EL display panel that do not cause problems such as solution leakage even when using a degassing apparatus employing a filter such as a hollow fiber membrane. The purpose is to

  In a method of manufacturing an organic EL display panel according to one aspect of the present invention, a step of preparing a substrate, a step of forming a plurality of organic EL elements on the substrate, and a sealing in which a conductive substance is added to an organic insulating material And degassing the solution from the solution using a filter that allows only gas to pass through, and applying the degassing solution for sealing onto the organic EL element to form a sealing layer. It is characterized by including.

  According to the above aspect, even if triboelectric charging occurs between the solution and the filter in the degassing step, the charge generated on the filter is dissipated by the conductive substance in the solution, and sparks are generated by the static electricity accumulated in the filter. And there is no risk of damage to the filter.

It is sectional drawing which shows typically the structure of the organic EL element 1 which concerns on embodiment. It is the schematic which shows typically the structure of the ink supply part in the sealing layer forming apparatus for forming a 2nd sealing layer. (A), (b) is a figure for demonstrating the principle of the degassing apparatus in a sealing layer forming apparatus. It is a schematic sectional drawing which shows the structure of a degassing apparatus. It is a figure which shows the structure of the inkjet apparatus in a sealing layer forming apparatus. It is a fragmentary sectional view which shows typically a part of manufacturing process of the organic EL element which concerns on embodiment, Comprising: (a) is a state in which the TFT layer was formed on the substrate, (b) is on the substrate The state in which the interlayer insulating layer is formed, (c) is the state in which the pixel electrode material is formed on the interlayer insulating layer, (d) is the state in which the hole injection layer material is formed on the pixel electrode material, e) shows a state in which the pixel electrode layer and the hole injection layer are formed. It is a fragmentary sectional view which shows typically a part of manufacturing process of the organic EL element which concerns on embodiment, and (a) is an interlayer insulation layer, a pixel electrode, and a partition material layer is formed on a hole injection layer. State (b) is the state in which the barrier layer is formed, (c) is the state in which the hole transport layer is formed on the hole injection layer, (d) is the light emitting layer on the hole injection layer Indicates a formed state. It is a fragmentary sectional view which shows typically a part of manufacturing process of the organic EL element which concerns on embodiment, Comprising: The state in which the electron carrying layer was formed on the light emitting layer and the partition layer, (b) Is the state in which the electron injection layer is formed on the electron transport layer, (c) is the state in which the counter electrode is formed on the electron injection layer, and (d) is the first sealing layer formed on the counter electrode Show the condition. It is a fragmentary sectional view which shows typically a part of manufacturing process of the organic EL element which concerns on embodiment, Comprising: (a) shows a mode that a 2nd sealing layer is formed on a 1st sealing layer, (B) shows the state in which the 2nd sealing layer was formed on the 1st sealing layer. It is a flowchart which shows the manufacturing process of the organic electroluminescent display panel which concerns on embodiment. It is a block diagram which shows the structure of the organic electroluminescence display provided with the organic electroluminescence display panel which concerns on embodiment.

<Circumstances leading to one aspect of the present disclosure>
The present inventors diligently studied the cause of damage to the deaerator. Then, a part of the wall surface of the hollow fiber membrane is melted and damaged, and the damage is caused by the frictional charge generated between the ink of the organic insulating material and the inner wall surface of the filter such as the hollow fiber membrane. I found that.
That is, as a filter material such as a hollow fiber membrane, a fluorine resin having resistance to an organic solvent is often used, and this fluorine resin is a material which is particularly easy to be charged in the charging train. When the ink flows through the filter, static electricity is generated due to the friction between the inner wall surface of the hollow fiber and the solution (frictional charging), and the organic material used as the ink is insulating. It is considered that the hollow fiber membrane is melted by the heat generated at that time and sparks are generated.

The inventor of the present invention has intensively studied a method of manufacturing a display panel which does not cause problems such as solution leakage even when a filter such as a hollow fiber membrane is used in the degassing process, and reaches one aspect of the present invention. .
<Outline of Embodiment for Carrying Out the Invention>
A method of manufacturing an organic EL display panel according to an aspect of the present invention comprises the steps of: preparing a substrate; forming a plurality of organic EL elements on the substrate; And degassing the sealing solution to which the sealing solution is added using a filter that passes only a gas, and applying the degassed sealing solution onto the organic EL element to form a sealing layer And the step of forming

According to the above aspect, even if static electricity is generated due to the frictional charge between the solution and the filter in the degassing step, the charge is dissipated by the conductive substance in the solution, thereby eliminating the risk of generating the spark and damaging the filter. .
Here, "degassing" means removing at least part or all of the gas contained in the solution.

The conductivity of the sealing solution in which a conductive substance is added to the organic insulating material is preferably greater than 1.0 × 10 ⁻¹² [S / m] and not more than 1.0 [S / m].
Thereby, generation | occurrence | production of the spark in a deaeration process can be prevented effectively.
Further, the filter may be configured of a hollow fiber membrane made of a fluorine-based resin.

The fluorine-based resin has a good resistance to organic solvents, and by forming a hollow fiber membrane filter, a long life and efficient degassing becomes possible, and the productivity is improved.
In addition, the conductive substance may be an ionic liquid.
The ionic liquid has high thermal stability and non-volatility, and the transparency of the resin can be maintained by adjusting the compatibility with the resin, and an excellent antistatic effect can be obtained even with a small amount of addition. be able to.

In addition, the organic insulating material may be an ultraviolet curing resin or a thermosetting resin. These cured resins cure in a short time by irradiation with ultraviolet light or heating, which contributes to improvement in productivity.
One aspect of the mode for carrying out the present invention is a sealing layer forming device for forming a sealing layer on a plurality of organic EL elements formed on a substrate, and adding a conductive substance to an organic insulating material , A tank for storing the sealing solution, a degassing means for degassing the sealing solution in the tank, and a coating means for applying the degassed sealing solution onto the organic EL element And.

The conductivity of the sealing solution in which a conductive substance is added to the organic insulating material is greater than 1.0 × 10 ⁻¹² [S / m] and not more than 1.0 [S / m].
Thereby, generation | occurrence | production of the spark in a deaeration means can be prevented effectively.
Here, the degassing means may be configured to degas the sealing solution by passing it through a filter made of a hollow fiber membrane made of a fluorine-based resin.

In addition, the conductive substance may be an ionic liquid.
The application unit may be an inkjet device.
The inkjet device can apply the solution for sealing accurately and uniformly to the necessary range even if it is a large-sized organic EL display panel, and the solution is not wasted, so that the productivity is excellent.

An organic EL display panel according to an aspect of the present invention comprises a substrate, a plurality of organic EL elements formed on the substrate, and a sealing layer formed above the organic EL element. And the sealing layer is characterized in that a conductive material is dispersed in an organic insulating material.
Here, the conductivity of the sealing layer formed by scattering the conductive material in the organic insulating material is larger than 1.0 × 10 ⁻¹² [S / m] and is 1.0 [S / m] or less. .

Embodiment
Hereinafter, the organic EL element according to the embodiment will be described. The following description is an example for explaining the configuration, operation, and effects according to one aspect of the present invention, and the present invention is not limited to the following forms except the essential part.
1. Configuration of Organic EL Element FIG. 1 is a partial cross-sectional view of an organic EL display panel 510 (see FIG. 11) according to the present embodiment. The organic EL display panel 510 includes a plurality of pixels configured of three types of organic EL elements that emit light of three colors (red, green, and blue). FIG. 1 shows the cross section of one pixel.

In the organic EL display panel 510, each organic EL element is a so-called top emission type in which light is emitted forward (upward in FIG. 1).
The organic EL elements of each color have almost the same configuration, and therefore, when not distinguished, they are described as the organic EL element 1.
As shown in FIG. 1, the organic EL element 1 includes a substrate 11, an interlayer insulating layer 12, a pixel electrode 13, a partition layer 14, a hole injection layer 15, a hole transport layer 16, a light emitting layer 17, an electron transport layer 18, The sealing layer 23 has a two-layer structure of the first and second sealing layers 21 and 22. The sealing layer 23 is composed of the electron injection layer 19, the counter electrode 20, and the sealing layer 23.

The substrate 11, the interlayer insulating layer 12, the electron transport layer 18, the electron injection layer 19, the counter electrode 20, and the sealing layer 23 are not formed for each pixel, but are provided in the organic EL display panel 510. It is formed in common to the plurality of organic EL elements 1.
(1) Substrate The substrate 11 includes a base material 111 which is an insulating material, and a TFT (Thin Film Transistor) layer 112. In the TFT layer 112, a drive circuit is formed for each pixel. The substrate 111 is, for example, a glass substrate, a quartz substrate, a silicon substrate, a metal substrate such as molybdenum sulfide, copper, zinc, aluminum, stainless steel, magnesium, iron, nickel, gold or silver, a semiconductor substrate such as gallium arsenide, a plastic substrate Etc. can be adopted.

  As a plastic material, any resin of thermoplastic resin and thermosetting resin may be used. For example, polyethylene, polypropylene, polyamide, polyimide (PI), polycarbonate, acrylic resin, polyethylene terephthalate (PET), polybutylene terephthalate, polyacetal, other fluorine resin, styrene resin, polyolefin resin, polyvinyl chloride resin, polyurethane resin, Various thermoplastic elastomers such as fluororubbers and chlorinated polyethylenes, epoxy resins, unsaturated polyesters, silicone resins, polyurethanes, etc., or copolymers, blends, polymer alloys, etc. mainly containing these, etc. are mentioned. The laminated body which laminated | stacked 1 type, or 2 or more types can be used.

(2) Interlayer Insulating Layer The interlayer insulating layer 12 is formed on the substrate 11. The interlayer insulating layer 12 is made of a resin material and is for planarizing a step on the top surface of the TFT layer 112. As a resin material, a positive photosensitive material is mentioned, for example. Moreover, acrylic resin, polyimide resin, siloxane resin, and phenol resin are mentioned as such a photosensitive material. Although not shown in the cross-sectional view of FIG. 1, contact holes are formed in the interlayer insulating layer 12 for each pixel.

(3) Pixel Electrode The pixel electrode 13 includes a metal layer made of a light reflective metal material, and is formed on the interlayer insulating layer 12. The pixel electrode 13 is provided for each pixel and is electrically connected to the TFT layer 112 through a contact hole (not shown).
In the present embodiment, the pixel electrode 13 functions as an anode.

  Specific examples of the metal material having light reflectivity include Ag (silver), Al (aluminum), aluminum alloy, Mo (molybdenum), APC (silver, palladium, alloy of copper), ARA (silver, rubidium, gold) And MoCr (alloy of molybdenum and chromium), MoW (alloy of molybdenum and tungsten), NiCr (alloy of nickel and chromium), and the like.

The pixel electrode 13 may be formed of a metal layer alone, but a laminated structure in which a layer formed of a metal oxide such as ITO (indium tin oxide) or IZO (indium zinc oxide) is laminated on the metal layer It is also good.
(4) Partition Layer The partition layer 14 is formed on the hole injection layer 15 in a state of exposing a partial region of the upper surface of the pixel electrode 13 and the hole injection layer 15 and covering the peripheral region. . A region (hereinafter referred to as “opening”) not covered with the partition wall layer 14 on the upper surface of the hole injection layer 15 corresponds to the sub-pixel. That is, the partition layer 14 has an opening 14 a provided for each sub-pixel.

In the present embodiment, the partition layer 14 is formed on the interlayer insulating layer 12 in a portion where the pixel electrode 13 is not formed. That is, in the portion in which the pixel electrode 13 is not formed, the bottom surface of the partition layer 14 is in contact with the top surface of the interlayer insulating layer 12.
The partition layer 14 is made of, for example, an insulating organic material (for example, an acrylic resin, a polyimide resin, a novolac resin, a phenol resin, or the like). The partition layer 14 functions as a structure for preventing the applied ink from overflowing when the light emitting layer 17 is formed by the application method, and a deposition mask when the light emitting layer 17 is formed by the evaporation method Act as a structure for placing the In the present embodiment, the partition wall layer 14 is made of a resin material, and examples of the material of the partition wall layer 14 include acrylic resins, polyimide resins, siloxane resins, and phenol resins. In the present embodiment, a phenolic resin is used.

(5) Hole Injection Layer The hole injection layer 15 is provided on the pixel electrode 13 for the purpose of promoting the injection of holes from the pixel electrode 13 to the light emitting layer 17. The hole injection layer 15 may be, for example, an oxide such as Ag (silver), Mo (molybdenum), Cr (chromium), V (vanadium), W (tungsten), Ni (nickel), Ir (iridium) or the like. It is a layer of conductive polymer material such as PEDOT (mixture of polythiophene and polystyrene sulfonic acid).

Among the above, the hole injection layer 15 made of metal oxide has a function of injecting holes into the light emitting layer 17 stably or assisting generation of holes, Have a function.
In the present embodiment, the hole injection layer 15 is made of tungsten oxide. When the hole injection layer 15 is formed of a transition metal oxide, a plurality of oxidation levels can be taken, so that a plurality of levels can be taken. As a result, the hole injection becomes easy, which contributes to the reduction of the driving voltage. Do.

(6) Hole Transport Layer The hole transport layer 16 is formed in the opening 14 a using a polymer compound not having a hydrophilic group. For example, polyfluorene or a derivative thereof, or a polymer compound such as polyarylamine or a derivative thereof which is not provided with a hydrophilic group can be used.
The hole transport layer 16 has a function of transporting holes injected from the hole injection layer 15 to the light emitting layer 17.

(7) Light Emitting Layer The light emitting layer 17 is formed in the opening 14 a and has a function of emitting light of each color of R, G, and B by recombination of holes and electrons. A well-known material can be utilized as a material of an organic light emitting layer. Specifically, for example, an oxinoid compound, a perylene compound, a coumarin compound, an azquamarin compound, an oxazole compound, an oxadiazole compound, a perinone compound, a pyrrolopyrrole compound, and a naphthalene described in Patent Publication (Japanese Unexamined Patent Publication No. 5-163488). Compound, anthracene compound, fluorene compound, fluoranthene compound, tetracene compound, pyrene compound, coronene compound, quinolone compound and azaquinolone compound, pyrazoline derivative and pyrazolone derivative, rhodamine compound, chrysene compound, phenanthrene compound, cyclopentadiene compound, stilbene compound, diphenylquinone Compound, styryl compound, butadiene compound, dicyanomethylenepyran compound, dicyanomethylenethiopyran compound, fluoresceinated Compounds, pyrilium compounds, thiapyrilium compounds, selenapyrilium compounds, telluropyrilium compounds, aromatic aldadiene compounds, oligophenylene compounds, thioxanthene compounds, cyanine compounds, acridine compounds, metal complexes of 8-hydroxyquinoline compounds, metals of 2-bipyridine compounds It is preferably formed of a fluorescent substance such as a complex, a complex of a Schiff salt and a Group III metal, an oxine metal complex, a rare earth complex and the like.

(8) Electron Transport Layer The electron transport layer 18 has a function of transporting electrons from the counter electrode 20 to the light emitting layer 17. The electron transport layer 18 is made of an organic material having high electron transportability, and does not contain an alkali metal and an alkaline earth metal.
Examples of the organic material used for the electron transport layer 18 include π electron low molecular weight organic materials such as oxadiazole derivative (OXD), triazole derivative (TAZ), and phenanthroline derivative (BCP, Bphen).

(9) Electron Injection Layer The electron injection layer 19 has a function of injecting electrons supplied from the counter electrode 20 to the light emitting layer 17 side. The electron injection layer 19 is formed, for example, by doping an organic material having high electron transportability with a doped metal selected from an alkali metal or an alkaline earth metal. In the embodiment, Ba is doped.

The metals corresponding to alkali metals are lithium (Li), sodium (Na), potassium (K), rubidium (Rb), cesium (Cs) and francium (Fr), and the metals corresponding to alkaline earth metals are It is calcium (Ca), strontium (Sr), barium (Ba) and radium (Ra).
Examples of the organic material used for the electron injection layer 19 include π electron low molecular weight organic materials such as oxadiazole derivative (OXD), triazole derivative (TAZ), and phenanthroline derivative (BCP, Bphen).

(10) Counter electrode The counter electrode 20 is made of a translucent conductive material and is formed on the electron injection layer 19. The counter electrode 20 functions as a cathode.
As a material of the counter electrode 20, for example, ITO or IZO can be used. Alternatively, as a material of the counter electrode 20, a metal such as silver, a silver alloy, aluminum, an aluminum alloy or the like may be used. In this case, since the counter electrode 20 needs to have translucency, the film thickness is formed as a thin film of about 20 nm or less.

(11) Sealing layer The sealing layer 23 is deteriorated by exposing the organic layer such as the hole transport layer 16, the light emitting layer 17, the electron transport layer 18, the electron injection layer 19 to moisture or air. The sealing layer 23 has a two-layer structure of a first sealing layer 21 and a second sealing layer 22 in the present embodiment.

The first sealing layer 21 is formed using, for example, a translucent material such as silicon nitride (SiN) or silicon oxynitride (SiON).
The second sealing layer 22 is made of, for example, an ultraviolet curable resin, and the component of the ionic liquid is dispersed in the inside. By providing the second sealing layer 22, the first sealing layer 21 is reinforced, and even if a crack or the like occurs in the first sealing layer 21, the organic functional layer inside is directly in contact with the open air. To prevent

In the present embodiment, since the organic EL display panel 510 is a top emission type, the second sealing layer 22 also needs to be formed of a light transmissive resin material.
(12) Others Although not shown in FIG. 1, a color filter or an upper substrate may be bonded via the second sealing layer 22. By bonding the upper substrate, the hole transport layer 16, the light emitting layer 17, the electron transport layer 18, and the electron injection layer 19 can be further protected from moisture, air, and the like.

2. Sealing Layer Forming Device Hereinafter, the configuration of a sealing layer forming device for forming the second sealing layer of the organic EL display panel of the embodiment by a wet process will be described.
The sealing layer forming apparatus includes an ink supply unit 1100 and an inkjet device 1200.
(1) Ink supply unit 1100
FIG. 2 is a schematic view showing the configuration of the ink supply unit 1100. As shown in FIG.

As shown in the figure, the ink supply unit 1100 includes a supply tank 110, a degassing device 160, transfer pumps 171 and 172, and a vacuum pump 173.
In the supply tank 110, an ink obtained by adding an ionic liquid as a conductive material to an ultraviolet (UV) curable resin as a material of the second sealing layer 22 is stored.
The UV curable resin is not particularly limited as long as it is an existing one such as urethane acrylate, acrylic resin acrylate, epoxy acrylate, etc., but in the top emission type organic EL display panel, it is excellent in light transmittance It is needless to say that is desirable.

The ionic liquid is a salt of liquid at normal temperature. By optimizing the structure of the ionic liquid and adjusting the compatibility with the resin, the transparency of the resin can be maintained, and an excellent antistatic effect can be obtained with a small amount of addition. Moreover, it is excellent in heat resistance and applicable also to kneading to resin, such as a polycarbonate.
Examples of the cation of the ionic liquid include ammonia-based, phosphonium-based, sulfonium-based, imidazolium-based and pyridine-based organic substances, and as the anion, AlCl ₄ ⁻ , I ⁻ , BF ₄ ⁻ , PF ₆ ⁻ , AsF ₆ ^{− _{, SbF 6 -, NbF6 -,}} CF 3 SO 3 -, C (CF 3 SO 2) 3 -, C 3 F 7 CO 2 -, C 4 F 9 SO 3 -, N (CF 3 SO 2) 2 -, N (C ₂ F ₅ SO ₂ ) ₂ ⁻ , N (CF ₃ SO ₂ ) (CF ₃ CO) ⁻ , etc., and many are commercially available.

However, the ionic liquid is not limited to this, and may be anything as long as it is added to the organic insulating material to impart conductivity.
The ink stored in the supply tank 110 is circulated in the degassing device 160 by the transfer pumps 171 and 172 to be degassed.
The ink in the supply tank 110 after the degassing process is supplied to the ink jet head 301 of the ink jet device 1200 (FIG. 5) and discharged onto the first sealing layer 21 to form the second sealing layer 22.

(2) Degassing Device FIG. 3 is a view showing the principle of degassing in the degassing device 160 in the present embodiment.
In the degassing device 160, a bundle (hollow fiber membrane bundle) 162 of hollow fiber membranes 161 as shown in FIG. 3A is incorporated. The hollow fiber membrane 161 is a hollow fiber-shaped filter membrane which transmits gas but does not transmit liquid.

Examples of the material of the hollow fiber membrane 161 include polyolefin resins such as polypropylene and poly-4-methylpentene-1, silicone resins such as polydimethylsiloxane and copolymers thereof, and fluorine resins such as PTFE and PFA. However, in particular, a fluorine-based resin excellent in the resistance to the organic solvent of the ink is desirable.
In addition, as a membrane shape (shape of a side wall) of the hollow fiber membrane 161, for example, a porous membrane, a microporous membrane, or a homogeneous membrane (non-porous membrane) having no porosity can be mentioned.

As shown in FIG. 3B, when the ink is allowed to pass through the hollow fiber membrane 161 and the pressure around the hollow fiber membrane 161 is reduced to vacuum or near vacuum, bubbles or dissolved gas in the ink from the side wall of the hollow fiber membrane 161 The only way out is the degassing process.
FIG. 4 is a schematic cross-sectional view showing an example of the configuration of the degassing apparatus 160. As shown in FIG.
As shown in the figure, the degassing device 160 includes a hollow fiber membrane bundle 162 in which a plurality of hollow fiber membranes 161 are bundled, and a housing 163 for housing the hollow fiber membrane bundle 162.

The housing 163 is formed by airtightly attaching a first lid 165 and a second lid 166 to the upper and lower openings of the cylindrical portion 164.
The space in the housing 163 is divided into three sealed spaces 163A to 163C by the first sealing part 167 and the second sealing part 168, and both ends of the hollow fiber membrane bundle 162 are respectively divided into the first sealing part 167 and the first sealing part 167. It is held by the second sealing portion 168. The first sealing portion 167 and the second sealing portion 168 are formed of resin. As resin used for sealing, an epoxy resin, a urethane resin, an ultraviolet curing resin, polyolefin resin etc. are mentioned, for example.

A suction port 1641 for evacuating the air in the space 163B is provided on the side surface of the cylindrical portion 164, an ink supply port 1651 is provided on the first lid portion 165, and the ink is discharged on the second lid portion 166. An outlet 1661 is provided.
The ink conveyed by the conveyance pump 171 (see FIG. 2) flows from the supply port 1651 into the space 163A in the first lid 165, flows in the hollow fiber membrane bundle 162, and the space in the second lid 166 It flows out into the inside of 163 C, is discharged from the discharge port 1661, and is returned to the supply tank 110 by the transfer pump 172.

Since the space 163B in the cylindrical portion 164 is decompressed by the vacuum pump 173 via the suction port 1641, air bubbles or dissolved gas in the ink flowing through the hollow fiber membrane bundle 162 escapes into the space 163B Is done.
In addition, it is desirable that all the dissolved gas contained in the ink be removed by the degassing treatment, but it is partially left if it does not affect the film formation in the process of the sealing layer forming step by the inkjet method. I don't care.

  If the ink consists only of an organic insulating material such as an ultraviolet curing resin, static electricity is generated due to the friction between the inner wall of the hollow fiber membrane 161 and the ink when the ink flows in the hollow fiber membrane 161, and the hollow fiber membrane The electric charge is accumulated on the inner surface of the side wall of the 161 and becomes a high potential, which sparks and damages the hollow fiber membrane 161. However, the static electricity generated by adding a small amount of ionic liquid to the ink as in this embodiment Was removed via the ionic liquid and sparks were eliminated. As a result, the life of the degassing device 160 can be extended.

The amount of ionic liquid to be added to the ultraviolet curing resin may be small, as long as it is sufficient to remove the static electricity accumulated on the inner wall of the hollow fiber membrane 161.
Specifically, the conductivity of the sealing ink obtained by adding the ionic liquid to the organic insulating material is greater than 1.0 × 10 ⁻¹² [S / m] and not more than 1.0 [S / m]. Is desirable.
When the conductivity of the ink is 1.0 × 10 ⁻¹² [S / m] or less, the discharge effect is not sufficiently obtained, and static electricity is gradually accumulated in the hollow fiber membrane 161 by continuous use for a long time , And sparks may occur.

  In the case of (A) top emission type, the sealing layer desirably has a light transmittance of at least 85% in design, and in order to enhance the conductivity of the ink, a conductive substance (ionic liquid) to be added There is a possibility that the sealing layer may fall below the above-mentioned light transmittance after curing if the amount of is too large, (a) if the conductivity of the second sealing layer 22 is too high, the second sealing layer 22 may The conductivity of the ink is, in view of the possibility that unintended conduction may occur to cause inconveniences such as a decrease in applied voltage or a decrease in light emission luminance when the wiring disposed in the peripheral portion of the substrate is generated. It is desirable that it is 1.0 [S / m] or less.

More preferably, the conductivity of the ink is 1.0 × 10 ⁻¹⁰ [S / m] or more and 1.0 × 10 ⁻⁷ [S / m] or less.
The specific addition amount of the ionic liquid is determined by experiment or the like in consideration of conditions such as the type of the organic insulating material and the number of charges of the ionic liquid so that the ink falls within the above-described range of conductivity.
(3) Ink Jet Device FIG. 5 is a view showing the main configuration of the ink jet device 1200 according to the present embodiment.

As shown in the figure, the inkjet device 1200 is configured of an inkjet table 200 and a head unit 300.
(3-1) Ink Jet Table As shown in FIG. 5, the ink jet table 200 is a so-called gantry-type operation table, and a gantry unit (moving frame) moves along a pair of guide shafts on the base table. It is arranged as possible.

  As a specific configuration, column-like stands 202A, 202B, 203A, and 203B are erected on the four corners of the upper surface of the plate-like base 201. In the inner area surrounded by the stands 202A, 202B, 203A and 203B, a fixed stage ST for mounting a substrate to be coated and ink are discharged immediately before coating to stabilize discharge characteristics. Ink pans (dish-like containers) IP to be used for the purpose are respectively disposed.

The stands 202 A and 202 B and the stands 203 A and 203 B hold the guide shafts 204 A and 204 B in parallel along the longitudinal (Y) direction of the base 201.
The gantry unit 210 is held by the guide shafts 204A and 204B via the linear motors 205 and 206.
With this configuration, when the inkjet device 1200 is driven, the gantry unit 210 reciprocates slidably along the longitudinal direction (Y-axis direction) of the guide shafts 204A and 204B by driving the pair of linear motors 205 and 206. Exercise.

  The gantry unit 210 is provided with a movable body (carriage) 220 formed of an L-shaped pedestal. A servomotor 221 is disposed on the moving body 220, and a gear (not shown) is attached to the tip of the drive shaft of the motor. The gear meshes with a rack of minute pitch formed in a guide groove 211 formed along the longitudinal direction (X direction) of the gantry portion 210, and when the servomotor 221 is driven, the moving body 220 has a so-called pinion rack mechanism , Precisely and reciprocably along the X-axis direction.

  The head portion 300 is attached to the movable body 220, and the gantry portion 210 is moved along the longitudinal direction of the guide shafts 204A and 204B in a state where the movable body 220 is fixed to the gantry portion 210. By moving the movable body 220 along the longitudinal direction of the gantry unit 210 while the gantry unit 210 is stopped, the head unit 300 can be scanned with respect to the substrate to be coated. The main scanning direction of the head unit 300 is a row (Y axis) direction, and the sub scanning direction is a column (X axis) direction.

The linear motors 205 and 206 and the servomotor 221 are driven and controlled by a control unit (not shown).
(3-2) Head Unit The head unit 300 adopts a known piezo method, and is configured of an inkjet head 301 and a main unit 302. The inkjet head 301 is fixed to the movable body 220 via the main body portion 302. The main body 302 incorporates a servomotor, and moves the inkjet head 301 in the vertical direction (Z-axis direction).

  The inkjet head 301 is provided with a plurality of nozzles 3011 (not shown in FIG. 5; see FIG. 7C etc.) on the surface (ejection surface) opposed to the fixed stage ST. These nozzles 3011 are longitudinal of the inkjet head 301 It is arranged in a row along the direction. The ink supplied to the inkjet head 301 is discharged from the nozzles 3011 as droplets onto the substrate to be coated.

The droplet discharge operation of each nozzle 3011 is controlled by a drive voltage applied to a piezo element (piezoelectric element) included in each nozzle 3011. The control unit (not shown) controls the drive signals applied to the respective piezoelectric elements to cause droplets to be discharged from the respective nozzles 3011.
The second sealing layer is formed by a wet process using the sealing layer forming apparatus having the above configuration. In addition, this sealing layer formation apparatus can be used also for formation of organic functional layers, such as a positive hole injection layer and a light emitting layer, by replacing | exchanging ink.

4. Method of Manufacturing Organic EL Element Hereinafter, a method of manufacturing the organic EL element 1 will be described with reference to the drawings. 6 (a) to 6 (e), 7 (a) to 7 (d), 8 (a) to 8 (d), 9 (a) and 9 (b), each step in the manufacture of the organic EL element 1 is shown. It is a schematic cross section which shows the state in. FIG. 10 is a flowchart showing a method of manufacturing the organic EL element 1.

(1) Formation of Substrate 11 First, as shown in FIG. 6A, the TFT layer 112 is formed on the base material 111 to form the substrate 11 (Step S1 in FIG. 10). The TFT layer 112 can be formed by a known TFT manufacturing method.
Next, as shown in FIG. 6B, the interlayer insulating layer 12 is formed on the substrate 11 (Step S2 in FIG. 10). The interlayer insulating layer 12 can be stacked, for example, using a plasma CVD method, a sputtering method, or the like.

Next, dry etching is performed on a portion of the interlayer insulating layer 12 on the source electrode of the TFT layer to form a contact hole (not shown). The contact hole is formed so that the surface of the source electrode is exposed at the bottom thereof.
Next, a connection electrode layer is formed along the inner wall of the contact hole. A part of the upper portion of the connection electrode layer is disposed on the interlayer insulating layer 12. For example, a sputtering method can be used to form the connection electrode layer, and after forming a metal film, patterning is performed using a photolithography method and a wet etching method.

(2) Formation of Pixel Electrode 13 and Hole Injection Layer 15 Next, as shown in FIG. 6C, a pixel electrode material layer 1300 is formed on the interlayer insulating layer 12 (Step S3 in FIG. 10). The pixel electrode material layer 1300 can be formed using, for example, a vacuum evaporation method, a sputtering method, or the like.
Next, as shown in FIG. 6D, the hole injection material layer 1500 is formed on the pixel electrode material layer 1300 (Step S4 in FIG. 10). The hole injection material layer 1500 can be formed, for example, using a reactive sputtering method or the like.

Then, as shown in FIG. 6E, the pixel electrode material layer 1300 and the hole injection material layer 1500 are patterned by etching to form a plurality of pixel electrodes 13 and a hole injection layer 15 partitioned for each sub-pixel. And (step S5 in FIG. 10).
The method of forming the pixel electrode 13 and the hole injection layer 15 is not limited to the method described above. For example, after the pixel electrode material layer 1300 is patterned to form the pixel electrode 13, the hole injection layer 15 is formed. May be

(3) Formation of partition wall layer 14 Next, as shown in FIG. 7A, the resin for partition wall layer, which is the material of the partition wall layer 14, is applied on the hole injection layer 15 and the interlayer insulating layer 12, A material layer 1400 is formed. The barrier rib material layer 1400 is formed by spin coating a solution obtained by dissolving a phenolic resin for a barrier rib layer in a solvent (for example, a mixed solvent of ethyl lactate and GBL) on the hole injection layer 15 and the interlayer insulating layer 12. It is formed by applying uniformly using.

Then, the partition wall layer 14 is formed by performing pattern exposure and development on the partition wall material layer 1400 (FIG. 7B, step S6 in FIG. 10), and the partition wall layer 14 is fired (step S7 in FIG. 10). Thus, the opening 14 a to be the formation region of the light emitting layer 17 is defined. The baking of the partition layer 14 is performed, for example, at a temperature of 150 ° C. or more and 210 ° C. or less for 60 minutes.
In the step of forming the partition layer 14, the surface of the partition layer 14 may be further surface-treated with a predetermined alkaline solution, water, an organic solvent or the like, or may be subjected to plasma treatment. This is performed for the purpose of adjusting the contact angle of the partition layer 14 to the ink (solution) applied to the opening 14 a or for the purpose of imparting water repellency to the surface.

(4) Formation of Hole Transport Layer 16 Next, as shown in FIG. 7C, an ink containing a constituent material of the hole transport layer 16 with respect to the opening 14a defined by the partition layer 14 is an inkjet head The ink is discharged from the nozzle 3011 of 301 and coated on the hole injection layer 15 in the opening 14a and baking (drying) is performed to form the hole transport layer 16 (Step S8 in FIG. 10).

(5) Formation of Light Emitting Layer 17 Next, as shown in FIG. 7D, the ink containing the constituent material of the light emitting layer 17 is discharged from the nozzle 3011 of the ink jet head 301 to transport the holes in the opening 14a. The light-emitting layer 17 is formed by applying on the layer 16 and baking (drying) (step S9 in FIG. 10).
(6) Formation of Electron Transport Layer 18 Next, as shown in FIG. 8A, the electron transport layer 18 is formed on the light emitting layer 17 and the partition layer 14 (Step S10 in FIG. 10). The electron transport layer 18 is formed, for example, by depositing an electron transporting organic material in common to the respective sub-pixels by vapor deposition.

(7) Formation of Electron Injection Layer 19 Next, as shown in FIG. 8B, the electron injection layer 19 is formed on the electron transport layer 18 (Step S11 in FIG. 10). The electron injection layer 19 is formed, for example, by depositing an electron transporting organic material and a doped metal in common to the respective sub-pixels by co-evaporation.
(8) Formation of Counter Electrode 20 Next, as shown in FIG. 8C, the counter electrode 20 is formed on the electron injection layer 19 (Step S12 in FIG. 10). The counter electrode 20 is formed by depositing ITO, IZO, silver, aluminum or the like by a sputtering method or a vacuum evaporation method.

(9) Formation of First Sealing Layer 21 Next, as shown in FIG. 8D, the first sealing layer 21 is formed on the counter electrode 20 (Step S13 in FIG. 10). The first sealing layer 21 can be formed by depositing SiON, SiN or the like by a sputtering method, a CVD method or the like.
(10) Formation of Second Sealing Layer 22 Next, as shown in FIG. 9A, the deaerator 160 is an ink containing an ultraviolet curable resin and an ionic liquid set within the aforementioned range of conductivity. After the degassing process, the ink is discharged from the nozzle 3011 of the ink jet head 301 in the ink jet apparatus 1200 and applied onto the first sealing layer 21, and then the ultraviolet light is irradiated and cured to form the second sealing layer 22. (Step S14 in FIG. 10).

The conductivity of the second sealing layer 22 after curing is the same as the conductivity of the ink before curing, and is larger than 1.0 × 10 ⁻¹² [S / m], 1.0 [S / m]. It becomes below.
Thereby, as shown in FIG. 9B, the organic EL display panel is completed.
5. Overall Configuration of Organic EL Display Device FIG. 11 is a schematic block diagram showing a configuration of an organic EL display device 500 provided with an organic EL display panel 510. As shown in FIG.

As shown in FIG. 11, the organic EL display device 500 is configured to include an organic EL display panel 510 and a drive control unit 520 connected thereto. The drive control unit 520 includes four drive circuits 521 to 524 and a control circuit 525.
The arrangement of the drive control unit 520 with respect to the organic EL display panel 510 is not limited to this.

<Effect>
As described in the above embodiment, when the second sealing layer is formed by applying an ink made of an insulating organic material, an ionic liquid is added to the ink to adjust the conductivity within a predetermined range. Thereby, since the charge of the hollow fiber membrane in the degassing device can be removed, sparks in the hollow fiber membrane do not occur, and the destruction of the degassing device can be prevented. In addition, it is suppressed that a part of the ink made of an insulating organic material in the second sealing layer causes an unexpected curing reaction due to charging, which may lead to problems such as solidified foreign matter in the device and clogging of the device piping. be able to. By these, the productivity of a high quality organic EL display panel can be improved. <Modification>
Although the organic light emitting panel and the display device according to the present disclosure have been described above based on the embodiment and the modification, the present invention is not limited to the above embodiment and the modification. By arbitrarily combining the components and functions in the embodiment and the modification within the scope not departing from the spirit of the present invention, the embodiment obtained by applying various modifications that the person skilled in the art thinks to the above embodiment and the modification The forms to be realized are also included in the present invention.

(1) In the above embodiment, as the ink for forming the second sealing layer 22, the ultraviolet curable resin to which the ionic liquid is added as the conductive material is used, but the invention is not limited thereto.
For example, instead of the ultraviolet curing resin, a thermosetting resin such as a phenol resin, a urea resin, a melamine resin, an epoxy resin, or a polyester (unsaturated polyester) may be used. It is needless to say that in the top emission type organic EL display panel, one having excellent light transmittance is desirable.

Although other organic insulating materials can also be used, it takes more time to cure than UV curable resins and thermosetting resins, so from the viewpoint of productivity, UV curable resins and thermosetting resins can be used. Resin is desirable.
(2) In the above embodiment, an ionic liquid is used as the conductive substance to be added to the ultraviolet curable resin, but the present invention is not limited to this, and any conductive substance can be provided as long as it is added to the organic insulating material to impart conductivity. It may be something. For example, conductive fine particles made of a metal such as silver may be added. Of course, the size of the conductive particles needs to be equal to or less than the size sufficient to pass through the nozzle 3011 of the ink jet apparatus 1200. Although the conductive fine particles remain in the second sealing layer 22 after curing of the ultraviolet curing resin, a small amount hardly affects the light transmittance.

It is needless to say that it is desirable that the conductivity of the ink falls within the range of the conductivity described in the above embodiment even when a conductive substance other than the ionic liquid is added.
(3) In the above embodiment, it is assumed that the cathode is the counter electrode and the top emission type organic EL display device. However, for example, the anode may be a counter electrode, and the cathode may be a pixel electrode. In addition, for example, a bottom emission type organic EL display device may be used.

  (4) Further, although the electron transport layer 18, the electron injection layer 19, the hole injection layer 15, and the hole transport layer 16 are essential components in the above embodiment, the present invention is not limited to this. For example, an organic EL element without the electron transport layer 18 or an organic EL element without the hole transport layer 16 may be used. Also, for example, instead of the hole injection layer 15 and the hole transport layer 16, a single hole injection transport layer may be provided. Also, for example, an intermediate layer made of an alkali metal may be provided between the light emitting layer 17 and the electron transporting layer 18.

  (5) Further, in the above embodiment, the ink jet apparatus using the piezo type ink jet head for discharging the ink by the volume change of the piezoelectric element has been described, but the thermal ink jet system for discharging the ink by the electrothermal transducer May be used. In addition, it is also possible to use a dispenser-type coating device that continuously discharges ink onto a substrate.

  (6) Moreover, it is not restricted to a display apparatus, A panel type illuminating device like an organic electroluminescent illuminating device may be used.

  The present invention is applied to a method of manufacturing an organic EL display panel or the like using an inkjet device or the like.

DESCRIPTION OF SYMBOLS 1 organic EL element 11 board | substrate 12 interlayer insulation layer 13 pixel electrode 14 partition wall 14a opening part 15 hole injection layer 16 hole transport layer 17 light emitting layer 18 electron transport layer 19 electron injection layer 20 counter electrode 21 1st sealing layer 22 Second sealing layer 23 sealing layer 110 supply tank 111 base material 112 TFT layer 160 degassing device 161 hollow fiber membrane 162 hollow fiber membrane bundle 163 housing 171, 172 transfer pump 173 vacuum pump 200 inkjet table 210 gantry part 220 moving body 300 head portion 301 inkjet head 500 organic EL display device 510 organic EL display panel 1100 ink supply portion 1200 inkjet device

Claims (12)

Preparing the substrate;
Forming a plurality of organic EL elements on the substrate;
Degassing a sealing solution prepared by adding a conductive substance to an organic insulating material using a filter through which only a gas passes;
Applying the degassed sealing solution onto the organic EL element to form a sealing layer;
A method of manufacturing an organic EL display panel, comprising: The conductivity of the sealing solution in which a conductive substance is added to the organic insulating material is greater than 1.0 × 10 ⁻¹² [S / m] and not more than 1.0 [S / m]. The manufacturing method of the organic electroluminescent display panel of Claim 1. The method of manufacturing an organic EL display panel according to claim 1, wherein the filter is formed of a hollow fiber film made of a fluorine-based resin. The method of manufacturing an organic EL display panel according to any one of claims 1 to 3, wherein the conductive substance is an ionic liquid. The method of manufacturing an organic EL display panel according to any one of claims 1 to 4, wherein the organic insulating material is an ultraviolet curing resin or a thermosetting resin. A sealing layer forming apparatus for forming a sealing layer on a plurality of organic EL elements formed on a substrate, comprising:
A tank for storing a sealing solution obtained by adding a conductive substance to an organic insulating material;
Degassing means for degassing the sealing solution in the tank;
An application means for applying the degassed sealing solution onto the organic EL element;
A sealing layer forming apparatus comprising: The conductivity of the sealing solution in which a conductive substance is added to the organic insulating material is greater than 1.0 × 10 ⁻¹² [S / m] and not more than 1.0 [S / m]. The sealing layer forming apparatus according to claim 6. The sealing layer according to claim 6 or 7, wherein the degassing means is configured to degas the sealing solution by passing it through a filter made of a hollow fiber membrane made of a fluorine resin. Forming device.   The sealing layer forming apparatus according to any one of claims 6 to 8, wherein the conductive material is an ionic liquid. The said coating means is an inkjet apparatus. The sealing layer forming apparatus in any one of Claim 6 to 9 characterized by the above-mentioned. A substrate,
A plurality of organic EL elements formed on the substrate;
A sealing layer formed above the organic EL element;
Equipped with
In the sealing layer, a conductive material is dispersed in an organic insulating material. The conductivity of the sealing layer in which the conductive material is dispersed in the organic insulating material is larger than 1.0 × 10 ⁻¹² [S / m] and is 1.0 [S / m] or less. The organic EL display panel according to claim 11.

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