JP2019212393A - Manufacturing method of electronic device and driving method of ink jet printing device - Google Patents

Abstract

To provide a manufacturing method of an electronic device capable of improving production efficiency.SOLUTION: A method of manufacturing an electronic device 10 including a first electrode layer 14 and a second electrode layer 18 provided on a board 12, and one or more functional layers provided between the first and second electrode layers, comprises: a layer formation step of forming at least one of the first electrode layer, the one or more functional layers and the second electrode layer by ink jet printing method using an ink jet printing device 24; and a standby step of stopping ejection of ink from the ink jet printing device, and putting the ink jet printing device on standby. In the standby step, electrical power is supplied to the ink jet printing device, and voltage supply to a piezoelectric element 36 of an ink jet head 28 in the ink jet printing device is blocked.SELECTED DRAWING: None

Description

  The present invention relates to an electronic device manufacturing method and an inkjet printing apparatus driving method.

  The electronic device includes a first electrode layer and a second electrode layer provided on a substrate, and one or a plurality of functional layers provided between the first electrode layer and the second electrode layer. When manufacturing this electronic device, at least one of the first electrode layer, the one or more functional layers, and the second electrode layer is formed by, for example, an inkjet printing apparatus as described in Patent Document 1 It can be formed using an inkjet printing method using

JP-A-10-153967

  In a method for manufacturing an electronic device including a step of forming a layer by an ink jet printing method, when a layer is not formed, ink ejection may be stopped and the ink jet printing apparatus may be put on standby. As described above, when the ink jet printing apparatus is put on standby, it is known to preliminarily vibrate the piezoelectric element by supplying a voltage to the piezoelectric element in the ink jet head of the ink jet printing apparatus.

  However, when the apparatus is on standby as described above, the ink included in the ink jet printing apparatus may be aggregated or solidified. In this case, the ink discharge port is clogged, and when the ink jet printing apparatus is used again, a problem occurs in the ink discharge, and the production efficiency of the electronic device is reduced.

  Accordingly, an object of one aspect of the present invention is to provide an electronic device manufacturing method capable of improving production efficiency. Another aspect of the present invention provides a method for driving an ink jet printing apparatus capable of preventing clogging of ink discharge ports during standby.

An electronic device manufacturing method according to one aspect of the present invention includes a first electrode layer and a second electrode layer provided on a substrate, and one provided between the first electrode layer and the second electrode layer. Or an electronic device manufacturing method for manufacturing an electronic device comprising a plurality of functional layers, wherein at least one of the first electrode layer, the one or more functional layers, and the second electrode layer, A layer forming step formed by an ink jet printing method using an ink jet printing device, and a standby step of stopping ejection of ink from the ink jet printing device and waiting the ink jet printing device. Power is supplied to the ink jet printing apparatus, and voltage supply to the piezoelectric element of the ink jet head included in the ink jet printing apparatus is interrupted.

  In the standby process, the voltage supply to the piezoelectric element is interrupted. Therefore, compared with the case where a voltage is applied to the piezoelectric element, there is almost no electric field near the piezoelectric element. Therefore, even if ink is present in the vicinity of the piezoelectric element, aggregation of components in the ink due to electric force and solidification of the components due to a chemical reaction caused by the electric field are suppressed. As a result, when the layer formation step is performed again after the standby step, the layer formation step can be performed without performing work for solving the problems associated with the aggregation and solidification (for example, clogging of the ink discharge ports). Or the frequency | count of the operation | work which eliminates the said malfunction at least can be reduced. Therefore, the production efficiency of electronic devices is improved.

  In the layer forming step, the ink may be ejected from the inkjet printing apparatus outside the formation region of the at least one layer before ejecting the ink from the inkjet printing apparatus to form the at least one layer. In the standby process, since the voltage supply to the piezoelectric element is interrupted, so-called preliminary vibration is not performed. Therefore, the ink meniscus shape may be different from the desired state. Therefore, in the layer forming step, before the ink is ejected from the ink jet printing apparatus to form the at least one layer, the ink is ejected from the ink jet printing apparatus outside the formation region of the at least one layer, The at least one layer can be formed after stabilizing to a desired meniscus shape.

  The ink ejected from the inkjet printing apparatus can be ink for forming a hole injection layer, a hole transport layer, or an electron transport layer. Such an ink is likely to cause aggregation and solidification as described above when a voltage is supplied to the piezoelectric element when the ink jet printing apparatus is put on standby. Therefore, the electronic device manufacturing method including the standby step is effective when the ink used in the layer forming step is an ink for forming a hole injection layer, a hole transport layer, or an electron transport layer.

  The ink ejected from the inkjet printing apparatus may include an aromatic hydrocarbon compound and an alkali metal salt or an alkaline earth metal salt. Such an ink is likely to cause aggregation and solidification as described above when a voltage is supplied to the piezoelectric element when the ink jet printing apparatus is put on standby. Therefore, the method for manufacturing an electronic device including the standby step is effective when the ink used in the layer forming step is an ink containing an aromatic hydrocarbon compound and an alkali metal salt or an alkaline earth metal salt.

  The piezoelectric element included in the inkjet head may be insulated. In this case, ink aggregation is less likely to occur.

  In the standby step, the ink jet printing apparatus may be kept on standby for one hour or longer. If the inkjet printing apparatus is kept on standby for 1 hour or more while supplying a voltage to the piezoelectric element, the above-described aggregation and solidification are likely to occur. Therefore, the electronic device manufacturing method including the standby step is effective when the ink jet printing apparatus is on standby for 1 hour or longer.

  The ink jet printing apparatus may be a circulation type ink jet apparatus that circulates the ink between an ink supply unit and an ink jet head that discharges the ink.

An inkjet printing apparatus driving method according to another aspect of the present invention includes: a discharge process for discharging ink from the inkjet printing apparatus; and a standby process for stopping the discharge of the ink from the inkjet printing apparatus and causing the inkjet printing apparatus to wait. In the standby step, power is supplied to the ink jet printing apparatus and voltage supply to the piezoelectric elements of the ink jet head of the ink jet printing apparatus is interrupted.

In the standby process, the voltage supply to the piezoelectric element is interrupted. Therefore, compared with the case where a voltage is applied to the piezoelectric element, there is almost no electric field near the piezoelectric element. Therefore, even if ink is present in the vicinity of the piezoelectric element, aggregation of components in the ink due to electric force and solidification of the components due to a chemical reaction caused by the electric field are suppressed. As a result, when the discharge step is performed after the standby step, the discharge step can be performed without performing an operation to eliminate clogging of the ink discharge ports due to the aggregation and solidification.

  According to one aspect of the present invention, an electronic device manufacturing method capable of improving production efficiency can be provided. According to another aspect of the present invention, it is possible to provide a method for driving an ink jet printing apparatus that can prevent clogging of ink discharge ports during standby.

FIG. 1 is a schematic diagram illustrating a schematic configuration of an organic EL device (electronic device) manufactured using the method for manufacturing an electronic device according to an embodiment. FIG. 2 is a schematic diagram for explaining an example of an ink jet apparatus used in a layer forming process included in the electronic device manufacturing method according to the embodiment. Drawing 3 is a mimetic diagram for explaining the layer formation process which the manufacturing method of the electronic device concerning one embodiment has.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The same reference numerals are assigned to the same elements, and duplicate descriptions are omitted. The dimensional ratios in the drawings do not necessarily match those described.

  FIG. 1 is a schematic diagram illustrating a schematic configuration of an organic electroluminescence device (hereinafter, also referred to as “organic EL device”) manufactured using the method for manufacturing an electronic device according to an embodiment. The organic EL device 10 includes a substrate 12, an anode layer (first electrode layer) 14, a device function unit 16, and a cathode layer (second electrode layer) 18. The anode layer 14, the device function unit 16, and the cathode layer 18 are stacked on the substrate 12 in the order of the anode layer 14, the device function unit 16, and the cathode layer 18. The organic EL device 10 may be a top emission type organic EL device or a bottom emission type organic EL device. Below, unless otherwise indicated, the organic EL device 10 is a bottom emission type organic EL device.

[substrate]
The substrate 12 has translucency with respect to light emitted from the organic EL device 10 (including visible light having a wavelength of 400 nm to 800 nm). An example of the thickness of the substrate 12 is 30 μm to 1100 μm.

  The substrate 12 may be a rigid substrate such as a glass substrate and a silicon substrate, or may be a flexible substrate such as a plastic substrate and a polymer film. The flexible substrate is a substrate having a property that the substrate can be bent without being sheared or broken even when a predetermined force is applied to the substrate.

  When the board | substrate 12 is a rigid board | substrate, the thickness of the board | substrate 12 is 50 micrometers-1100 micrometers, for example. When the board | substrate 12 is a flexible board | substrate, the thickness of the board | substrate 12 is 30 micrometers-700 micrometers, for example.

  A barrier layer having a moisture barrier function may be formed on the substrate 12. The barrier layer may have a function of barriering gas (for example, oxygen) in addition to the function of barriering moisture.

[Anode layer]
The anode layer 14 is provided on the substrate 12. For the anode layer 14, an electrode having optical transparency is used. As the electrode exhibiting light transmittance, a thin film containing a metal oxide, metal sulfide, metal, or the like having high electrical conductivity can be used. A thin film having high light transmittance is preferably used as the electrode exhibiting light transmittance. The anode layer 14 may have a network structure made of a conductor (for example, metal). The thickness of the anode layer 14 can be determined in consideration of light transmittance, electrical conductivity, and the like. The thickness of the anode layer 14 is usually 10 nm to 10 μm, preferably 20 nm to 1 μm, and more preferably 50 nm to 500 nm.

  Examples of the material of the anode layer 14 include indium oxide, zinc oxide, tin oxide, indium tin oxide (abbreviated as ITO), indium zinc oxide (abbreviated as IZO), gold, platinum, silver, Copper etc. are mentioned, Among these, ITO, IZO, or tin oxide is preferable. The anode layer 14 can be formed as a thin film made of the exemplified materials. As the material of the anode layer 14, organic substances such as polyaniline and derivatives thereof, polythiophene and derivatives thereof may be used. In this case, the anode layer 14 can be formed as a transparent conductive film.

[Device function section]
The device function unit 16 is a function unit that contributes to light emission of the organic EL device 10 such as charge transfer and charge recombination in accordance with the voltages applied to the anode layer 14 and the cathode layer 18. The device function unit 16 includes a light emitting layer that is a functional layer. As will be described later, the device function unit 16 may have a functional layer other than the light emitting layer. That is, the device function unit 16 has one or a plurality of functional layers.

  The light emitting layer is a functional layer having a function of emitting light (including visible light). The light emitting layer is an organic layer, and is generally composed of an organic substance that mainly emits at least one of fluorescence and phosphorescence, or an organic substance and a dopant material that assists the organic substance. The dopant material is added, for example, in order to improve the light emission efficiency or change the light emission wavelength. The organic substance may be a low molecular compound or a high molecular compound. The thickness of the light emitting layer is, for example, 2 nm to 200 nm.

  Examples of the organic substance that is a light-emitting material that mainly emits at least one of fluorescence and phosphorescence include the following dye materials, metal complex materials, and polymer materials.

(Dye material)
Examples of dye-based materials include cyclopentamine derivatives, tetraphenylbutadiene derivative compounds, triphenylamine derivatives, oxadiazole derivatives, pyrazoloquinoline derivatives, distyrylbenzene derivatives, distyrylarylene derivatives, pyrrole derivatives, thiophene ring compounds. Pyridine ring compounds, perinone derivatives, perylene derivatives, oligothiophene derivatives, oxadiazole dimers, pyrazoline dimers, quinacridone derivatives, coumarin derivatives, and the like.

(Metal complex materials)
Examples of the metal complex material include rare earth metals such as Tb, Eu, and Dy, or Al, Zn, Be, Ir, Pt, etc. as the central metal, and oxadiazole, thiadiazole, phenylpyridine, phenylbenzimidazole, quinoline. Examples include metal complexes having a structure as a ligand, for example, iridium complexes, metal complexes having light emission from a triplet excited state such as platinum complexes, aluminum quinolinol complexes, benzoquinolinol beryllium complexes, benzoxazolyl zinc complexes, Examples include benzothiazole zinc complex, azomethyl zinc complex, porphyrin zinc complex, phenanthroline europium complex and the like.

(Polymer material)
As polymer materials, polyparaphenylene vinylene derivatives, polythiophene derivatives, polyparaphenylene derivatives, polysilane derivatives, polyacetylene derivatives, polyfluorene derivatives, polyvinylcarbazole derivatives, the above dye materials and metal complex light emitting materials are polymerized. Things.

(Dopant material)
Examples of the dopant material include perylene derivatives, coumarin derivatives, rubrene derivatives, quinacridone derivatives, squalium derivatives, porphyrin derivatives, styryl dyes, tetracene derivatives, pyrazolone derivatives, decacyclene, and phenoxazone.

  The device function unit 16 may include at least one functional layer in addition to the light emitting layer. That is, the device function unit 16 may have a multilayer structure. For example, at least one of a hole injection layer and a hole transport layer may be provided between the anode layer 14 and the light emitting layer. Between the light emitting layer and the cathode layer 18, at least one of an electron transport layer and an electron injection layer may be provided.

  The hole injection layer is a functional layer having a function of improving hole injection efficiency from the anode layer 14 to the light emitting layer. The hole injection layer may be an inorganic layer or an organic layer. The hole injection material constituting the hole injection layer may be a low molecular compound or a high molecular compound.

  Examples of the low molecular compound include metal oxides such as vanadium oxide, molybdenum oxide, ruthenium oxide, and aluminum oxide, metal phthalocyanine compounds such as copper phthalocyanine, and carbon.

  Examples of the polymer compound include polyaniline, polythiophene, polythiophene derivatives such as polyethylenedioxythiophene (PEDOT), polypyrrole, polyphenylene vinylene, polythienylene vinylene, polyquinoline and polyquinoxaline, and derivatives thereof; aromatic amine structure And a conductive polymer such as a polymer containing in the main chain or side chain.

  The optimum value of the thickness of the hole injection layer varies depending on the material used. The thickness of the hole injection layer may be appropriately determined in consideration of the required characteristics and the ease of film formation. The thickness of the hole injection layer is, for example, 1 nm to 1 μm, preferably 2 nm to 500 nm, and more preferably 5 nm to 200 nm.

  The hole transport layer is a functional layer having a function of improving the efficiency of hole injection from the hole injection layer (the anode layer 14 in the case of no hole injection layer) to the light emitting layer.

  The hole transport layer is an organic layer containing a hole transport material. The hole transport material is not limited as long as it is an organic compound having a hole transport function. Examples of the organic compound having a hole transport function include polyvinyl carbazole or a derivative thereof, polysilane or a derivative thereof, a polysiloxane derivative having an aromatic amine residue in a side chain or a main chain, a pyrazoline derivative, an arylamine derivative, and a stilbene derivative. , Triphenyldiamine derivative, polyaniline or derivative thereof, polythiophene or derivative thereof, polypyrrole or derivative thereof, polyarylamine or derivative thereof, poly (p-phenylene vinylene) or derivative thereof, polyfluorene derivative, aromatic amine residue High molecular compounds, and poly (2,5-thienylene vinylene) or a derivative thereof can be given.

  As examples of the hole transport material, JP-A-63-70257, JP-A-63-175860, JP-A-2-135359, JP-A-2-135361, JP-A-2-20988, Examples thereof include hole transport materials described in JP-A-3-37992 and JP-A-3-152184.

  The optimum value of the thickness of the hole transport layer varies depending on the material used. The thickness of the hole transport layer may be determined as appropriate in consideration of the required characteristics and the ease of film formation. The thickness of the hole transport layer is, for example, 1 nm to 1 μm, preferably 2 nm to 500 nm, and more preferably 5 nm to 200 nm.

  The electron transport layer is a functional layer having a function of improving the electron injection efficiency from the electron injection layer (the cathode layer 18 in the case where no electron injection layer is present) to the light emitting layer.

  The electron transport layer is an organic layer containing an electron transport material. A known material can be used as the electron transport material. Examples of the electron transport material include a material obtained by doping an aromatic hydrocarbon compound with an alkali metal salt or an alkaline earth metal salt. Specific examples of electron transport materials include oxadiazole derivatives, anthraquinodimethane or derivatives thereof, benzoquinone or derivatives thereof, naphthoquinone or derivatives thereof, anthraquinones or derivatives thereof, tetracyanoanthraquinodimethane or derivatives thereof, fluorenone derivatives, Examples include diphenyldicyanoethylene or a derivative thereof, a diphenoquinone derivative, or a metal complex of 8-hydroxyquinoline or a derivative thereof, polyquinoline or a derivative thereof, polyquinoxaline or a derivative thereof, polyfluorene or a derivative thereof, and the like.

  The thickness of the electron transport layer can be appropriately determined in consideration of the required characteristics and the ease of film formation. The thickness of the electron transport layer is, for example, 1 nm to 1 μm, preferably 2 nm to 500 nm, and more preferably 5 nm to 200 nm.

  The electron injection layer is a functional layer having a function of improving the efficiency of electron injection from the cathode layer 18 to the light emitting layer.

  The electron injection layer may be an inorganic layer or an organic layer. As the material constituting the electron injection layer, an optimum material is appropriately selected according to the type of the light emitting layer. Examples of the material constituting the electron injection layer include alkali metals, alkaline earth metals, alloys containing one or more of alkali metals and alkaline earth metals, oxides of alkali metals or alkaline earth metals, halides , Carbonates, or mixtures of these substances. Examples of alkali metals, alkali metal oxides, halides, and carbonates include lithium, sodium, potassium, rubidium, cesium, lithium oxide, lithium fluoride, sodium oxide, sodium fluoride, potassium oxide, potassium fluoride , Rubidium oxide, rubidium fluoride, cesium oxide, cesium fluoride, lithium carbonate, and the like. Examples of alkaline earth metal, alkaline earth metal oxides, halides and carbonates include magnesium, calcium, barium, strontium, magnesium oxide, magnesium fluoride, calcium oxide, calcium fluoride, barium oxide, fluoride Examples include barium, strontium oxide, strontium fluoride, and magnesium carbonate.

  In addition, a layer obtained by mixing a conventionally known electron transporting organic material and an alkali metal organometallic complex can be used as the electron injection layer.

An example of the layer configuration of the device function unit 16 is shown below. In the example of the layer configuration described below, the anode layer and the cathode layer are also shown in parentheses in order to show the positional relationship between the anode layer 14 and the cathode layer 18 and various functional layers.
(A) (Anode layer) / Hole injection layer / Light emitting layer / (Cathode layer)
(B) (anode layer) / hole injection layer / light emitting layer / electron injection layer / (cathode layer)
(C) (anode layer) / hole injection layer (or hole transport layer) / light emitting layer / electron transport layer / electron injection layer / (cathode layer)
(D) (anode layer) / hole injection layer / hole transport layer / light emitting layer / (cathode layer)
(E) (anode layer) / hole injection layer / hole transport layer / light emitting layer / electron injection layer / (cathode layer)
(F) (anode layer) / hole injection layer / hole transport layer / light emitting layer / electron transport layer / electron injection layer / (cathode layer)
(G) (anode layer) / light emitting layer / electron transport layer (or electron injection layer) / (cathode layer)
(I) (anode layer) / light emitting layer / electron transport layer / electron injection layer / (cathode layer)
The symbol “/” means that the layers on both sides of the symbol “/” are joined to each other.

The device function unit 16 may have one light emitting layer or two or more light emitting layers. In any one of the layer configurations of the above configuration examples (a) to (i), when the stacked body disposed between the anode layer 14 and the cathode layer 18 is referred to as [structural unit I], two layers Examples of the configuration of the device function unit 16 having the light emitting layer include the layer configuration shown in the following (j). The layer structure of the two structural units I may be the same or different.
(J) (anode layer) / [structural unit I] / charge generation layer / [structural unit I] / (cathode layer)

  The charge generation layer is a layer that generates holes and electrons by applying an electric field. Examples of the charge generation layer include a thin film containing vanadium oxide, ITO, molybdenum oxide, or the like.

When “[structural unit I] / charge generation layer” is [structural unit II], the configuration of an organic EL device having three or more light emitting layers includes the layer configuration shown in the following (k).
(K) (Anode layer) / [Structural unit II] x / [Structural unit I] / (Cathode layer)
The symbol “x” represents an integer of 2 or more, and “[structural unit II] x” represents a stacked body in which [structural unit II] is stacked in x stages. The layer structure of the plurality of structural units II may be the same or different.

  The device function unit 16 may be configured by directly laminating a plurality of light emitting layers without providing the charge generation layer.

[Cathode layer]
The cathode layer 18 is provided on the device function unit 16. The thickness of the cathode layer 18 varies depending on the material used, and is set in consideration of electrical conductivity, durability, and the like. The thickness of the cathode layer 18 is usually 10 nm to 10 μm, preferably 20 nm to 1 μm, and more preferably 50 nm to 500 nm.

  The material of the cathode layer 18 is light emission that the device function unit 16 has so that light from the device function unit 16 (specifically, light from the light emitting layer) is reflected by the cathode layer 18 and travels toward the anode layer 14 side. A material having a high reflectance with respect to light from the layer (particularly visible light) is preferable. Examples of the material of the cathode layer 18 include aluminum and silver. As the cathode layer 18, a transparent conductive electrode made of a conductive metal oxide, a conductive organic material, or the like may be used.

  The organic EL device 10 may include a sealing member for preventing deterioration of the device function unit 16 due to moisture or the like. The sealing member may be provided on the cathode layer 18 so as to seal at least the device function unit 16. In the form in which the organic EL device 10 includes a sealing member, for example, a part of the anode layer 14 and the cathode layer 18 can be pulled out of the sealing member for external connection.

  Next, an example of a method for manufacturing the organic EL device 10 will be described. When the organic EL device 10 is manufactured, the anode layer 14 is formed on the substrate 12 (anode layer forming step). Then, the device function part 16 is formed on the anode layer 14 (device function part formation process). Subsequently, the cathode layer 18 is formed on the device function unit 16 (cathode layer forming step). The organic EL device 10 is manufactured through such steps.

  In the form in which the organic EL device 10 includes the sealing member, a sealing step of sealing the device function unit 16 with the sealing member may be performed after the cathode layer forming step.

  For example, when the long substrate 12 is used for manufacturing the organic EL device 10, for example, a plurality of device formation regions are virtually set on the long substrate 12, and the anode layer 14 and the device function are provided for each device formation region. The part 16 and the cathode layer 18 are formed. Thereby, since the organic EL device 10 is formed for every device formation area, the several organic EL device 10 can be manufactured by separating the elongate board | substrate 12 for every device formation area.

  In the form in which the long substrate 12 has flexibility, at least one of the anode layer forming step, the device function part forming step, and the cathode layer forming step may be performed by, for example, a roll-to-roll method. In the form in which the device function unit 16 includes a plurality of functional layers, at least one step of forming each of the plurality of functional layers may be performed in a roll-to-roll manner.

  Next, the manufacturing method of the organic EL device 10 will be described more specifically.

  In the manufacture of the organic EL device 10, at least one of the anode layer 14, one or a plurality of functional layers of the device function unit 16, and the cathode layer 18 (hereinafter referred to as “predetermined layer” for convenience of explanation) Is formed by an ink jet printing method using an ink jet printing apparatus. Thus, when forming a predetermined layer with an inkjet printing method, the said inkjet printing apparatus once manufactures the organic EL device 10 according to the manufacturing process of the organic EL device 10 mentioned above, for example, Then, the next organic EL device 10 is produced. Wait until manufacturing.

  That is, the manufacturing method of the organic EL device (electronic device) 10 includes a layer forming step of forming the predetermined layer by an ink jet printing method and a standby step of waiting the ink jet printing apparatus. The layer forming step and the standby step will be described.

[Layer formation process]
FIG. 2 and FIG. 3 are used when the device functional unit 16 has an electron transport layer (functional layer) and the electron transport layer is formed by an ink jet printing method (that is, when the electron transport layer is the predetermined layer). To explain. Hereinafter, for convenience of explanation, a coating film that becomes an electron transport layer is referred to as a coating film 20, and an electron transport layer is referred to as an electron transport layer 22.

  FIG. 2 is a schematic diagram for explaining a schematic configuration of the ink jet printing apparatus 24 used in the layer forming step. FIG. 3 is a drawing for explaining the layer forming step. In FIG. 3, a long base substrate 26 on which the electron transport layer 22 is formed is schematically illustrated as a film (or plate) -like member. The base substrate 26 is the substrate 12 provided with the anode layer 14 and at least one functional layer provided between the electron transport layer 22 and the anode layer 14 in the device function unit 16. In a form in which layers other than the electron transport layer 22 are formed in the layer forming step, the base substrate 26 is a substrate including the substrate 12 and at least one layer provided on the substrate 12 until the layer forming step.

  As shown in FIG. 2, the inkjet printing apparatus 24 includes an inkjet head 28, an ink supply unit 30, and a control unit 32. The control unit 32 controls the inkjet printing apparatus 24.

  The inkjet head 28 extends in one direction. The ink jet head 28 is formed with a plurality of ink discharge ports 34 that are discretely arranged in the one direction (the width direction of the base substrate 26), and a piezoelectric element 36 (for example, corresponding to each ink discharge port 34). Piezo element) is provided. The diameter of the ink discharge port 34 is, for example, 5 μmφ to 200 μmφ. For example, the liquid contact part (the piezoelectric element 36, the wiring part, etc.) inside the inkjet head 28 may be subjected to an insulation process (for example, a process for covering the liquid contact part with an insulating material). When the piezoelectric element 36 is covered with an insulator, the portion other than the connection portion between the piezoelectric element 36 and the wiring portion may be covered with the insulator. By vibrating the piezoelectric element 36, ink is ejected from the ink ejection port 34. The amount of ink discharged from each of the plurality of ink discharge ports 34 (including the case where the discharge amount is 0) is controlled by the control unit 32.

  As shown in FIG. 3, the ink jet head 28 is disposed to face the surface of the base substrate 26 on the side where the electron transport layer 22 is formed, and the extending direction of the ink jet head 28 is the width direction (longitudinal direction) of the base substrate 26. (The direction orthogonal to the direction) is substantially aligned.

  By controlling the ink discharge amount (including the case where the discharge amount is 0) from each of the plurality of ink discharge ports 34 included in the inkjet head 28 arranged as described above by the control unit 32, a predetermined amount on the base substrate 26 is obtained. It can apply | coat with a predetermined pattern on the formation area of a layer.

  The ink supply unit 30 supplies ink to the inkjet head 28. The ink supply unit 30 includes, for example, a tank that stores ink. The ink supply unit 30 and the inkjet head 28 are connected by a pipe 38 for circulating ink between them. That is, the ink jet printing device 24 is a circulation type ink jet device. The pipe 38 is provided with a flow rate adjustment unit 40 such as a pump. When the control unit 32 controls the flow rate adjusting unit 40, the flow rate of the ink supplied to the inkjet head 28 can be adjusted, and the ink circulates between the ink supply unit 30 and the inkjet head 28.

  The inkjet printing apparatus 24 may include a plurality of inkjet heads 28. In this case, the plurality of inkjet heads 28 are arranged along the longitudinal direction of the base substrate 26. In the form in which the inkjet printing apparatus 24 including the plurality of inkjet heads 28 is a circulation type, the ink may circulate between the plurality of inkjet heads 28 and the ink supply unit 30.

  As shown in FIG. 3, in the layer forming step, the ink containing the material of the electron transport layer 22 is transferred from the inkjet printing device 24 to the base substrate 26 (or the substrate 12) while the base substrate 26 is transported in the longitudinal direction. Coating is performed on the formation region of the predetermined layer to form the coating film 20. The ink containing the material for the electron transport layer 22 is, for example, an ink containing an aromatic hydrocarbon compound and an alkali metal salt or an alkaline earth metal salt. Then, the electron transport layer 22 is obtained by drying the coating film 20 in the drying device 42. The drying device 42 may be, for example, a drying device using infrared rays, or may be another method (hot air, hot plate, etc.). The drying device 42 may combine different drying methods.

  Here, the case where the electron transport layer is the predetermined layer (the case where the layer forming step is included in the device function part forming step) has been described. However, at least one of the anode layer 14, one or a plurality of functional layers of the device function unit 16, and the cathode layer 18 may be formed by the layer forming process. In other words, the layer forming step may be included in at least one of the anode layer forming step and the cathode layer forming step.

  Of the one or more functional layers and the anode layer 14 included in the device function unit 16, layers other than the predetermined layer can be formed by, for example, a dry film forming method, a plating method, a coating method other than the ink jet printing method, or the like. Examples of the dry film forming method include a vacuum deposition method, a sputtering method, an ion plating method, and a CVD method. Examples of coating methods other than inkjet printing include slit coating, micro gravure coating, gravure coating, bar coating, roll coating, wire bar coating, spray coating, screen printing, flexographic printing, Examples thereof include an offset printing method and a nozzle printing method.

  In the case where the cathode layer 18 is a layer other than the predetermined layer, the cathode layer 18 is, for example, a coating method such as slit coater method, gravure printing method, screen printing method, spray coater method, vacuum deposition method, sputtering method, metal thin film. Can be formed by a laminating method for thermocompression bonding.

[Standby process]
In the standby process, the ejection of ink from all the ink ejection ports 34 of the inkjet printing apparatus 24 is stopped. In the standby process, power is supplied to the inkjet printing apparatus 24 while voltage supply to the piezoelectric element 36 is interrupted. The interruption of the voltage supply to the piezoelectric element 36 means that the voltage supplied to the piezoelectric element 36 is 0.5 V or less. In the embodiment in which the ink jet printing apparatus 24 is a circulation type ink jet printing apparatus, the ink may be circulated during the standby process by the power supplied to the ink jet printing apparatus 24. In the standby process, the inkjet printer 24 is allowed to wait for, for example, one hour or longer. In the standby process, the inkjet printing apparatus 24 may be kept on standby for 1 day or more, and may be kept on standby for 3 days or more, for example, 6 days or more.

  An example of the standby process is as described above, after the organic EL device 10 is manufactured once by performing the manufacturing process of the organic EL device 10 including the anode layer forming process, the device function part forming process, and the cathode layer forming process, for example. In this step, the inkjet printing apparatus 24 is put on standby until the next organic EL device 10 is manufactured by performing the same manufacturing process.

  In this case, the process of manufacturing the organic EL device 10 including the anode layer forming process, the device function part forming process, and the cathode layer forming process is referred to as a first device manufacturing process. Next, when the process of manufacturing the organic EL device 10 is referred to as a second device manufacturing process, the organic EL device manufacturing method includes a first device manufacturing process, a standby process, and a second device manufacturing process. At least one of the anode layer forming step, the device function part forming step, and the cathode layer forming step included in the first device manufacturing step and the second device manufacturing step is the layer forming step.

  The standby process is not limited to the case where the inkjet printing apparatus 24 is allowed to wait between the first and second device manufacturing processes. For example, when the organic EL device 10 is manufactured by performing the anode layer forming step, the device function part forming step, and the cathode layer forming step (in other words, when each of the first and second device manufacturing steps is performed). This includes the case where the inkjet printing apparatus 24 is put on standby for troubles, condition changes, or inspections of other apparatuses on the production line.

  In the standby step, as described above, the voltage supply to the piezoelectric element 36 is cut off. Therefore, an electric field is not substantially generated in the vicinity of the piezoelectric element 36 as compared with the case where a voltage is applied to the piezoelectric element 36. Therefore, even if ink is present in the vicinity of the piezoelectric element 36, the components contained in the ink are prevented from aggregating due to an electric force, or solidifying due to a chemical reaction caused by the electric field. . Thereby, it is possible to prevent problems (for example, clogging of the ink discharge ports 34) based on the aggregation and solidification of the ink. Prevention of the said malfunction is not limited to the malfunction by implementation of one waiting process. That is, in the standby process of the present embodiment, as described above, the aggregation and solidification of the ink itself can be suppressed in the standby process. For this reason, for example, even if the standby process is repeated, accumulation of aggregated or solidified ink is prevented, and the above-described problems can be prevented. As a result, when carrying out the layer formation step again after the standby step, it is possible to carry out the layer formation step without performing the work to eliminate the above-mentioned problems, or at least the number of operations to eliminate the above-mentioned problems can be reduced, The production efficiency of the organic EL device 10 is improved.

  In the standby process, since the voltage supply to the piezoelectric element 36 is cut off, preliminary vibration of the piezoelectric element 36 is not performed. Therefore, the ink meniscus shape may be different from the desired state. Therefore, in the method of manufacturing the organic EL device 10 including the standby step, before forming the predetermined layer (for example, the electron transport layer) by ejecting ink from the ink jet apparatus in the layer forming step, outside the formation region of the predetermined layer. It is preferable to carry out the step of ejecting ink once. Accordingly, even if the layer formation step is performed again after the standby step, the ink can be ejected in a desired meniscus shape.

  The ejection of ink outside the formation region is not limited to the case where ink is ejected outside the formation region of the predetermined layer on the base substrate 26. For example, when the inkjet head 28 is movably installed, the base substrate This includes the case where ink is once ejected at a location different from 26.

  When the ink ejected from the inkjet printing apparatus 24 is an ink for forming the electron transport layer 22 (for example, an ink containing an aromatic hydrocarbon compound and an alkali metal salt or an alkaline earth metal salt) ) If a voltage is supplied to the piezoelectric element 36 when the inkjet printer 24 is put on standby, the above-described aggregation and solidification are likely to occur. Therefore, in the method of manufacturing the organic EL device (electronic device) 10 including the standby process of cutting off the voltage supply to the piezoelectric element when the inkjet printing apparatus 24 is standby, the ink used in the layer formation process is the electron transport layer 22. This is effective when the ink is for forming. For the same reason, the manufacturing method of the organic EL device (electronic device) 10 including the standby step is performed when the ink used in the layer forming step is an ink for forming a hole injection layer or a hole transport layer. It is valid.

  Next, the operation and effect of cutting off the voltage supply to the piezoelectric element 36 in the standby process will be further described with reference to experimental examples. However, the present invention is not limited to the following experimental examples.

[Experiment 1]
In Experimental Example 1, a circulation type ink jet printing apparatus was used. In the ink jet apparatus of Experimental Example 1, an ink jet head in which an electrode for supplying a voltage to the piezoelectric element is not insulated is used. A plurality of ink discharge ports are formed in the ink jet head. In Experimental Example 1, the ink for the electron transport layer was ejected from the ink jet printing apparatus onto the water absorbent sheet being conveyed. The ink contained an aromatic hydrocarbon compound and an alkali metal salt.

  When the ink discharge port is clogged, the ink is not discharged, so that a portion where the ink is not absorbed is generated in the water absorbing sheet, and the portion appears as a streak. It was confirmed that no streaks were formed on the water-absorbing sheet (that is, the ink discharge ports were not clogged) by the initial discharge of the ink.

  Thereafter, power was supplied to the ink jet printing apparatus to circulate the ink, while the ink jet printing apparatus was put on standby while the voltage supply to the piezoelectric element was cut off. That is, the standby process was performed. After carrying out the standby process, ink was ejected from the inkjet printing apparatus onto the water absorbent sheet, and the clogged state of the ink ejection port was confirmed based on the presence or absence of streaks in the water absorbent sheet. In Experimental Example 1, the above standby and ink ejection were repeated every day. In Experimental Example 1, changes over time of the inkjet printing apparatus were observed for 10 days every day with the same inkjet head.

[Experiment 2]
In Experimental Example 2, a circulation type ink jet printing apparatus was used. In the ink jet apparatus of Experimental Example 2, an experiment similar to that of Experimental Example 1 was performed except that an ink jet head in which a piezoelectric element was insulated was used.

[Experiment 3]
Experimental Example 3 is a comparative experiment with respect to Experimental Example 1. In Experimental Example 3, the same type of inkjet printing apparatus as in Experimental Example 1 was used. In Experimental Example 3, the same experiment as in Example 1 was performed, except that when the inkjet printing apparatus was put on standby, a voltage was supplied to the piezoelectric element and the piezoelectric element was previbrated.

[Comparison of the results of Experimental Examples 1 and 2 and Experimental Example 3]
In Experimental Example 3 in which a voltage was supplied to the piezoelectric element in the standby process, streaks were confirmed in the water-absorbing sheet when ink was ejected from the ink jet printing apparatus to the water-absorbing sheet after repeating the standby for four days. The streaks increased as the number of days of follow-up increased. That is, in Experimental Example 3, it is considered that ink aggregation and solidification occurred during standby of the ink jet printing apparatus, which accumulated, and that the ink ejection port was clogged when the ink jet apparatus was waited four times.

  On the other hand, in Examples 1 and 2, the streaks were not generated in the water-absorbing sheet even when the ink was ejected from the standby inkjet printing apparatus to the water-absorbing sheet in all observations regardless of the number of elapsed days.

  Therefore, according to the results of Experimental Examples 1 and 2, and Experimental Example 3, the ink discharge port is clogged (in other words, the ink is discharged) by performing a standby process in which the voltage supply to the piezoelectric element is cut off and the inkjet printing apparatus is put on standby. It can be understood that the agglomeration and solidification) can be prevented more reliably.

  In Experimental Example 1 and Experimental Example 3, the experiment was performed under the same conditions except that the voltage was not applied to the piezoelectric element in the standby process. Therefore, it is considered that the clogging of the ink ejection port in Experimental Example 3 is caused by an electric field generated in the vicinity of the piezoelectric element by applying a voltage to the piezoelectric element in the standby process. For this reason, when the piezoelectric element is insulated, the ink discharge port is less likely to be clogged. Therefore, even when the voltage supply to the piezoelectric element is cut off and the ink jet printing apparatus is put on standby, the piezoelectric element is insulated so that problems caused by the aggregation and solidification of ink in the standby process are further reduced. It can be understood that it can be prevented.

  In the foregoing, various embodiments of the present invention have been described. However, the present invention is not limited to the various embodiments illustrated, but is defined by the scope of the claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of the claims. Is done.

  For example, when the method for manufacturing an electronic device (for example, an organic EL device) includes the layer formation process and the standby process described in the above embodiment, the inkjet printing apparatus ejects ink and ejects ink from the inkjet printing apparatus. And a standby method of waiting for the inkjet printing apparatus to be driven. Further, also in the standby process provided in this driving method, power is supplied to the ink jet printing apparatus and voltage supply to the piezoelectric elements of the ink jet head is interrupted. Therefore, although one aspect of the present invention has been described focusing on the method for manufacturing an electronic device in the above embodiment, the present invention also relates to a method for driving an inkjet printing apparatus. In the driving method of the ink jet printing apparatus, since the voltage supply to the piezoelectric element is interrupted in the standby process, it is possible to prevent clogging of the ink discharge ports in the standby process.

  The standby period of the inkjet printing apparatus in the standby process is not limited to one day as exemplified in Experimental Examples 1 and 2. As described above, the standby period of the inkjet printing apparatus in the standby process may be, for example, 1 hour or longer. Depending on the type of ink, the size of the ink ejection port, etc., even if the standby process is about 1 hour (or repeated), if voltage is supplied to the piezoelectric element in the standby process, ink aggregation and solidification may occur. Because there is sex.

  Although the embodiment in which the first electrode layer is an anode layer and the second electrode layer is a cathode layer has been described, the first electrode layer may be a cathode layer and the second electrode layer may be an anode layer.

  The present invention is also applicable to the manufacture of organic electronic devices other than organic EL devices, such as organic solar cells, organic photodetectors, and organic transistors. Furthermore, the present invention can also be applied to the manufacture of electronic devices in which all functional layers of the device function unit are made of an inorganic material.

  DESCRIPTION OF SYMBOLS 10 ... Organic EL device (electronic device), 12 ... Board | substrate, 14 ... Anode layer (1st electrode layer), 18 ... Cathode layer (2nd electrode layer), 24 ... Inkjet printing apparatus, 28 ... Inkjet head.

Claims (8)

An electron for manufacturing an electronic device comprising a first electrode layer and a second electrode layer provided on a substrate, and one or a plurality of functional layers provided between the first electrode layer and the second electrode layer A device manufacturing method comprising:
A layer forming step of forming at least one of the first electrode layer, the one or more functional layers, and the second electrode layer by an inkjet printing method using an inkjet printing apparatus;
A standby step of stopping the ejection of ink from the inkjet printing apparatus and waiting the inkjet printing apparatus;
With
In the standby step, power is supplied to the ink jet printing apparatus and voltage supply to the piezoelectric elements of the ink jet head of the ink jet printing apparatus is interrupted.
Electronic device manufacturing method. In the layer forming step, before the ink is ejected from the inkjet printing apparatus to form the at least one layer, the ink is ejected from the inkjet printing apparatus to the outside of the formation area of the at least one layer;
The manufacturing method of the electronic device of Claim 1. The ink ejected from the inkjet printing apparatus is an ink for forming a hole injection layer, a hole transport layer or an electron transport layer.
The manufacturing method of the electronic device of Claim 1 or 2. The ink ejected from the inkjet printing apparatus includes an aromatic hydrocarbon compound and an alkali metal salt or an alkaline earth metal salt.
The manufacturing method of the electronic device as described in any one of Claims 1-3. The piezoelectric element included in the inkjet head is insulated.
The manufacturing method of the electronic device as described in any one of Claims 1-4. In the standby step, the inkjet printing apparatus is kept on standby for 1 hour or longer.
The manufacturing method of the electronic device as described in any one of Claims 1-5. The inkjet printing apparatus is a circulation type inkjet apparatus that circulates the ink between an ink supply unit and an inkjet head that discharges the ink.
The manufacturing method of the electronic device as described in any one of Claims 1-6. An ejection process for ejecting ink from an inkjet printing apparatus;
A standby step of stopping ejection of the ink from the inkjet printing apparatus and waiting the inkjet printing apparatus;
Have
In the standby step, power is supplied to the ink jet printing apparatus and voltage supply to the piezoelectric elements of the ink jet head of the ink jet printing apparatus is interrupted.
A method for driving an inkjet printing apparatus.

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