TW202235170A - Ink ejection quantity measurement/adjustment method, ink ejection quantity measurement/adjustment device, panel manufacturing system for organic el display panel, organic el display panel manufacturing method, ink, and organic el display panel manufactured using ink - Google Patents

Abstract

A measurement/adjustment method including at least a measurement method for measuring the quantity of ink ejected from an ink ejection head, wherein in said measurement method, ink is ejected from the ink ejection head onto a substrate, an image of the ink that was ejected onto the substrate is acquired, the quantity of ink ejected from the ink ejection head is derived on the basis of information obtained from the image, and the ink that was ejected onto the substrate is maintained, after a prescribed time period has passed since being ejected from the ink ejection head, in a quantity that is a constant proportion of the quantity of ink that was ejected from the ink ejection head.

Description

Method for measuring and adjusting ejection amount of ink, apparatus for measuring and adjusting ink ejection amount, panel manufacturing system for organic EL display panel, method for manufacturing organic EL display panel, ink, and organic EL display panel manufactured using ink

The present invention relates to a method for measuring and adjusting the ejection amount of ink using an inkjet head, a device for measuring and adjusting the amount of ink ejection, a panel manufacturing system for organic electroluminescent (EL) display panels, a method for manufacturing organic EL display panels, ink and organic EL display panels made using ink.

Conventionally, as an apparatus for forming a desired pattern on a substrate using ink in which a functional material is dispersed or dissolved, there is known an inkjet apparatus that ejects ink into droplets. The inkjet device forms a pattern by arranging droplets of ink ejected from the inkjet head on an arbitrary position on the substrate while moving the substrate and the inkjet head relatively.

In recent years, inkjet devices have been used in the manufacture of large-screen color filters, organic EL display panels, and the like. One of the manufacturing steps of the organic EL display panel is the film-forming step of the organic EL film, and inkjet printing technology can be used in this step. It is known that in the manufacture of color filters or organic EL display panels, if there is variation in the amount of ink ejected (arranged) to the substrate, the thickness of the formed film will vary, resulting in uneven light emission in the organic EL display panel s reason. Therefore, in order to manufacture an organic EL display panel with high precision, it is necessary to control the ejection amount of ink for each nozzle.

In Patent Document 1, liquid droplets are ejected to a weighing scale to measure the ejection weight of each inkjet head, and based on the measurement result, control is performed so that the ejection weight of each inkjet head is uniform. In Patent Document 2, the film thickness of ejected liquid droplets is measured, and the ejection pattern is changed based on the measured film thickness to adjust the ejection weight. In Patent Document 3, when the optical axis of the observation optical system coincides with the center of the ring-shaped illuminator, light is irradiated from the ring-shaped illuminator to the droplet. The resulting image of the virtual image of the annular illuminator is used to determine the height of the droplet. Patent Document 4 discloses a technique for measuring the landing diameter of a droplet of each nozzle based on image data of a droplet formed by evaporation of a solvent. In addition, in Patent Document 4, a cover for preventing evaporation is used in order to prevent volume changes due to evaporation of droplets from landing to measurement. [Prior art literature] [Patent Document]

[Patent Document 1] Japanese Patent Application Publication No. 2004-209429 [Patent Document 2] Japanese Patent Application Publication No. 2006-341231 [Patent Document 3] Japanese Patent Application Publication No. 2010-169413 [Patent Document 4] Japanese Patent Application Publication No. 2019-169413

[Problem to be Solved by the Invention]

On the other hand, in the measurement method of Patent Document 1, a large amount of ink is required, and a large amount of time is required for the measurement, so that the operating rate of the inkjet device is greatly reduced. In the method of Patent Document 2, means for calculating the ejection weight of the ejected liquid droplets for each nozzle is not included, and there is a possibility that the ejection weight of each inkjet head may be uneven. In addition, only combining the technique described in Patent Document 3 with, for example, an inkjet device is difficult to say that it is sufficient for accurate measurement of finer liquid droplets in the progress of high-definition. In addition, since the volume of tiny droplets of organic EL materials or the like tends to change due to evaporation of the solvent, it is necessary to accurately obtain the volume of the droplets in consideration of such volume changes. In the droplet volume measurement method described in Patent Document 4, a cover and its arrangement mechanism are used to prevent evaporation. Such a mechanism becomes a large-scale structure as a whole of the device.

The present invention is made to solve the above-mentioned problems, and its object is to accurately measure the ejection amount of liquid droplets without the need for an evaporation prevention mechanism in view of the problem that the amount of liquid droplets is likely to change due to the evaporation of the solvent. . [Means to solve the problem]

In order to solve the above-mentioned problems, the present invention has the following configurations. That is, a measurement adjustment method comprising at least a measurement method of measuring the ejection amount of ink from an inkjet head, The measurement methods include: an ejecting step, ejecting ink from the inkjet head onto the substrate; an acquiring step of acquiring an image of ink jetted onto said substrate; and an deriving step of deriving an ejection amount of ink from the inkjet head based on information obtained from the image, The ink ejected onto the base material maintains an amount proportional to the amount of ink ejected from the ink jet head after a predetermined time elapses after ejection from the ink jet head.

In addition, in an aspect of the present invention, the measurement adjustment method further includes a drying step of drying the ink jetted onto the substrate within the predetermined time period, and the obtaining step is performed in the Performed after the drying step.

In addition, in one aspect of the present invention, the ink includes a solvent and a functional material, and the solvent includes an organic solvent having a boiling point of 250° C. or higher.

Moreover, another aspect of this invention has the following structures. That is, a measurement adjustment method comprising at least a measurement method of measuring the ejection amount of ink from an inkjet head, The measurement methods include: an ejecting step, ejecting ink from the inkjet head onto the substrate; an acquiring step of acquiring an image of ink jetted onto said substrate; and an deriving step of deriving an ejection amount of ink from the inkjet head based on information obtained from the image, The ink contains a solvent and a functional material, The solvent includes an organic solvent having a boiling point of 250° C. or higher.

In addition, in one aspect of the present invention, the measurement adjustment step further includes a drying step of drying the ink jetted onto the substrate within a predetermined time period, and the obtaining step is performed in the drying step Execute afterwards.

Moreover, in one form of this invention, the said predetermined time is 5 minutes or more.

In addition, in one aspect of the present invention, the ink includes a solvent and a functional material, and the solvent includes an organic solvent having a boiling point of 300° C. or higher.

Moreover, in one aspect of this invention, the said ink contains 20 weight% or more of the said organic solvent.

Moreover, in one aspect of this invention, the said base material is coated with the liquid-repellent coating material which has liquid-repellency with respect to the said ink.

In addition, in an aspect of the present invention, the deriving step includes: taking the diameter of the droplet of ink from said image, using at least the obtained diameter to derive the volume of ink on said substrate, Based on the derived volume of ink on the base material, the ejection amount of ink from the inkjet head is derived.

In addition, in one aspect of the present invention, the measurement adjustment method further includes an adjustment step of adjusting the ejection amount from the inkjet head based on the ejection amount of ink derived in the derivation step.

In addition, in one aspect of the present invention, the measurement adjustment method is used when forming at least any one of the light emitting layer, the hole injection layer, and the hole transport layer among the functional layers constituting the organic EL display panel.

Moreover, another aspect of this invention has the following structures. That is, an ink ejection amount measurement and adjustment device using the measurement and adjustment method.

Moreover, another aspect of this invention has the following structures. That is, a panel manufacturing system for an organic EL display panel includes the ink ejection amount measurement and adjustment device.

Moreover, another aspect of this invention has the following structures. That is, a method of manufacturing an organic EL display panel using the measurement adjustment method.

Moreover, another aspect of this invention has the following structures. That is, the method for manufacturing an organic EL display panel uses the above-mentioned panel manufacturing system.

Moreover, another aspect of this invention has the following structures. That is, an ink for said measurement adjustment method, The ink comprises: a solvent, and a functional material corresponding to the functional layer, The solvent includes an organic solvent having a boiling point of 250° C. or higher.

Moreover, another aspect of this invention has the following structures. That is, an ink used in said ink ejection amount measurement and adjustment device, The ink comprises: a solvent, and a functional material corresponding to the functional layer, The solvent includes an organic solvent having a boiling point of 250° C. or higher.

Moreover, another aspect of this invention has the following structures. That is, an ink used in the panel manufacturing system of the organic EL display panel, The ink comprises: a solvent, and a functional material corresponding to the functional layer, The solvent includes an organic solvent having a boiling point of 250° C. or higher.

Moreover, in one aspect of this invention, the said ink contains 20 weight% or more of the said organic solvent.

In addition, in one aspect of the present invention, after drying for a predetermined time, the ink maintains a constant ratio relative to the volume before drying.

Moreover, another aspect of this invention has the following structures. That is, an organic EL display panel using the ink to form a functional layer. [Effect of the invention]

According to the present invention, it is possible to accurately measure and/or adjust the ejection amount of liquid droplets with a simple structure.

Hereinafter, embodiments for implementing the present invention will be described with reference to the drawings and the like. Furthermore, the embodiments described below are for explaining one embodiment of the present invention, and are not intended to limit and explain the present invention. In addition, all the structures described in each embodiment are not limited to solve the present invention. The structure required for the subject. In addition, in each drawing, the correspondence relationship is shown by attaching the same reference numeral to the same structural element.

<First Embodiment> [device structure] An example of the structure of an inkjet device according to an embodiment of the present invention will be described with reference to FIGS. 1 and 2 . 1 and 2 show an ink ejection amount measurement and adjustment device from an inkjet head that can perform the steps of measuring and adjusting the ejection amount of ink from an inkjet head described later in the inkjet device according to this embodiment. FIG. 1 is a schematic side view schematically showing the structure of an inkjet device 1 according to this embodiment. FIG. 2 is a schematic plan view schematically showing the configuration of the inkjet device 1 according to the present embodiment. Hereinafter, the main scanning direction of the stage 40 (that is, the conveyance direction of the substrate) is referred to as the X-axis direction, and the sub-scanning direction perpendicular to the main scanning direction is referred to as the Y-axis direction, which is perpendicular to the X-axis direction and the Y-axis direction. The vertical direction of is set as the Z-axis direction. Furthermore, let the rotational direction around the Z-axis direction be the θ direction. In each figure, description will be made assuming that the respective axis directions correspond to each other.

The inkjet device 1 has: an X-axis table 10 extending along the main scanning direction (X-axis direction); and a pair of Y-axis tables 11 erected across the X-axis table 10 and extending along the sub-scanning direction ( Y-axis direction) extension exists. On the upper surface of the X-axis table 10 , a pair of X-axis guide rails 12 are provided extending along the X-axis direction, and an X-axis linear motor (not shown) is provided on the X-axis guide rails 12 . On the upper surface of the Y-axis table 11 , a Y-axis guide rail 13 is provided extending along the Y-axis direction, and a Y-axis linear motor (not shown) is provided on the Y-axis guide rail 13 . A carriage unit 20 and a camera unit 30 are provided on a pair of Y-axis tables 11 .

(carriage unit) The carriage unit 20 includes a carriage support portion 21 , a carriage 22 , and an inkjet head 23 . On the lower surface of the carriage unit 20, one or more carriages 22 and one or more inkjet heads 23 are included corresponding to the types of ink to be ejected. In this embodiment, for example, a plurality of inkjet heads 23 having a structure of a line head type corresponding to the width of the substrate are provided in the Y-axis direction. A plurality of nozzles are formed on the lower surface of the inkjet head 23 , that is, the ink ejection surface, and ink droplets are ejected from the nozzles. For example, in the case of ejecting three inks corresponding to three colors of red (R), green (G), and blue (B), three rows of inkjet heads 23 are provided. In addition, the number of types of inks that the inkjet device 1 can handle is not particularly limited, and can be increased or decreased depending on the structure of the manufactured product. In addition, a supply unit (not shown) for supplying ink is connected to the carriage unit 20 , and ink is supplied at an appropriate time.

The carriage support portion 21 is attached to the Y-axis guide rail 13 and is configured to be movable in the Y-axis direction by a Y-axis linear motor (not shown) provided on the Y-axis guide rail 13 . For example, the carriage unit 20 may also be structured as follows: when ejecting ink, it moves in a manner positioned on the X-axis table 10 as shown in FIG. position for cleaning. Examples of the cleaning operation include pre-ejection of ink, wiping of the ejection surface of the inkjet head 23 , and the like.

FIG. 3 is a diagram schematically showing how ink droplets 202 are ejected from the inkjet head 23 . The inkjet head 23 according to this embodiment shows an example using a piezoelectric method. In the piezoelectric method, by applying a driving voltage to a piezoelectric element (not shown) inside the inkjet head 23, the piezoelectric element expands and contracts, and a predetermined amount of ink is ejected from a fine hole called a nozzle hole 201. Drop 202. The ejected ink droplets 202 land on the substrate B placed on the stage 40 . Furthermore, the arrangement and number of nozzle holes 201 are not particularly limited, and are not limited to the example shown in FIG. 3 .

(camera unit) The camera unit 30 photographs the substrate B placed on the stage 40 , and acquires an image including the substrate B and the ink droplets 202 jetted thereon. The camera unit 30 includes a camera 31 as an imaging unit.

As shown in FIG. 1 , the camera 31 is installed on one side of the Y-axis table 11 among the pair of Y-axis tables 11 , and is supported by the camera support portion 32 . In the example of FIG. 1 , the camera 31 is installed on the downstream side of the conveyance direction (X-axis direction) of the base material B rather than the inkjet head 23 . A moving mechanism (not shown) for moving the camera 31 is provided on the camera support portion 32 , and the camera 31 can move freely in the Y-axis direction. For example, the cameras 31 are provided corresponding to the carriage unit 20 (the carriage 22 ), and a plurality of cameras may be provided along the Y-axis direction. Therefore, a plurality of cameras 31 can be installed to shorten the time for shooting operations. The camera 31 of the present embodiment has a function of capturing an image capable of reproducing the resolution of each of the ink droplets 202 ejected onto the base material B. As shown in FIG. In addition, a structure may be adopted in which the substrate B is irradiated with illumination light from an illuminator (not shown) when photographing with the camera 31 . As a light source of an illuminator (not shown), for example, a light emitting diode (LED) or the like can be used.

(Stage) The stage 40 is, for example, a vacuum adsorption stage, which can absorb and fix the substrate B. As shown in FIG. In this embodiment, the substrate B corresponds to a substrate for measuring the ejection amount of ink or a substrate for forming a pixel pattern. When it is necessary to explain each base material separately, subscripts are shown as the base material B1 for measuring the ejection amount of ink and the base material B2 for forming the display panel. Material B. On the substrate B1, a liquid-repellent coating material is applied to the surface onto which the ink is ejected, and has liquid-repellency with respect to the ink. The composition of the liquid-repellent coating material here is determined according to the composition of the ink.

The stage 40 is rotatably supported in the θ direction around the Z-axis by the stage rotation mechanism 41 provided on the lower surface side of the stage 40 . The stage rotation mechanism 41 is supported by an X-axis slider 42 provided on the lower surface side of the stage rotation mechanism 41 . The X-axis slider 42 is mounted on the X-axis guide rail 12 and is configured to be freely movable in the X-axis direction by an X-axis linear motor (not shown) provided on the X-axis guide rail 12 .

Although details will be described later, a display panel that can be manufactured using the inkjet device 1 of this embodiment includes a plurality of layers. These layers include one or more layers that can be formed by inkjet. Therefore, in the case of forming these layers separately, multiple structures shown in FIG. 1 or FIG. 2 can be provided and applied. Since the type of ink used in each layer is different, a mechanism required for measurement or formation, such as the carriage unit 20 , or a substrate B1 for measuring the ejection amount of ink may be provided corresponding to the function of each layer.

(control device) The inkjet device 1 includes a control device 50 . The control device 50 can be realized by an information processing device including, for example, a not-shown control unit, a storage unit, and an output unit. The control unit may include a central processing unit (CPU), a micro processing unit (Micro Processing Unit, MPU), a digital signal processor (DSP), or a dedicated circuit. The storage unit includes volatile or non-volatile storage media such as a hard disk drive (HDD), read-only memory, or random access memory, and can input and output various information according to instructions from the control unit. In addition, the storage unit stores programs for realizing the processing according to the present embodiment. The output unit includes a speaker, a lamp, or a display device such as a liquid crystal display, and performs various outputs in accordance with instructions from the control unit. The output method by the output device is not particularly limited, for example, visual output based on screen output may be used. In addition, the output unit may be a network interface with a communication function, and the output operation may be performed by sending data to an external device (not shown) via a network (not shown).

The control device 50 collectively performs, for example, position control of the stage 40 or the carriage unit 20 , or ink ejection control by the inkjet head 23 . During the ejection of ink, the control device 50 outputs its control signal to the inkjet head 23 according to the formed image pattern. In addition, the control device 50 controls the imaging operation by the camera unit 30 to measure the ejection amount of ink. In addition, the control device 50 performs various controls for producing the display panel D. As shown in FIG. In this embodiment, as the display panel D, an organic EL display panel will be described as an example.

[Characteristics of the ink] The characteristics of the ink of this embodiment will be described. The ink of the present embodiment is described as an ink used in manufacturing an organic EL display panel as an example, but it is not limited thereto as long as it is used in manufacturing a product to which the above-mentioned inkjet device 1 can be applied. In the manufacture of organic EL display panels, it is required to adjust the ejection amount of ink with high precision, and the ink ejection amount of each nozzle must be measured for such adjustment, but it is difficult to accurately measure the volume change caused by ink drying. On the other hand, in this embodiment, an ink having a characteristic composition in terms of tendency to change volume due to drying is used.

The ink includes a solute including a functional material, and a solvent including an organic solvent. The functional material is a material for realizing the function of the layer formed by the inkjet method among the layers constituting the organic EL display panel. The organic solvent must be an organic solvent capable of dissolving or dispersing the solute containing the functional material.

4 and 5 are diagrams for explaining the characteristics of the ink of this embodiment. Here, description will be given using the ink of this embodiment (Example) and the ink for comparison (Comparative Example).

Compared with the conventional ink, the ink of this embodiment has a characteristic that the volume after drying is stable after a certain period of time. FIG. 4 is a graph showing changes in droplet volume over time for the ink of the present embodiment and a comparative example. In FIG. 4 , the horizontal axis represents the time [min] after the ink droplet is left to stand after ejection, and the vertical axis represents the volume [pl] of the ink droplet. The volumes of the ink droplets of the first example and the comparative example were assumed to be the same.

In the example of FIG. 4 , in the case of the comparative example, the volume of the ink droplet decreases with the lapse of time, and becomes almost 0 when the left-to-stand time of 10 minutes has elapsed. On the other hand, in the case of the example, the volume of the ink droplet decreased with the lapse of time, but the volume change almost disappeared after a lapse of a certain standing time, and the volume remained substantially constant. As shown by the arrows in FIG. 4 , in the example, the reduction in volume almost disappeared after 5 minutes of standing time, and the volume remained constant. FIG. 5 shows the value of the volume for each elapsed time (standing time) corresponding to FIG. 4 . In both the examples and the comparative examples, the volumes decreased in substantially the same tendency until a certain period of time passed. Afterwards (after 5 minutes have elapsed), the tendency to decrease produces a difference. That is, the ink of the present embodiment has a property that the evaporation of the solvent almost disappears after a certain period of time (ie, drying time) has elapsed, and the volume change of the ink can be suppressed and stabilized. The term "stabilized by suppressing the volume change of the ink" means that the evaporation of the solvent from the ink is almost eliminated, whereby the volume change of the ink is almost eliminated, and a constant ratio is maintained. In the present embodiment, the state of maintaining a constant ratio may be, for example, a state in which the volume reduction rate is 0.01 pl/min or less.

In this case, for example, the volume of ink stabilized by suppressing the volume change is assumed to be 1.00 pl. Here, when an image acquisition step of acquiring an image of the ink ejected onto the substrate B is performed after ejecting the ink from the inkjet head 23 , the time from the ejection step of the ink to the acquisition step fluctuates for some reason. Even assuming that the above-mentioned time fluctuates by 1 minute, the volume change is less than 1% (*), which is a good characteristic in the production of organic EL panels. From the viewpoint of improving the accuracy of the ink delivery amount from the inkjet head 23, it is more preferably 0.005 pl/min or less, particularly preferably 0.001 pl/min or less. ((*) When the volume of 1.00 pl ink is reduced at 0.01 pl/min, the amount of volume reduction for 1 minute is 0.01 pl. It is 1% of 1.00 pl.)

In order to realize the above-mentioned characteristics, the composition of the ink of this embodiment is determined. As mentioned above, the ink is composed of a solvent and a solute. Examples of organic solvents that can be used in the present embodiment include aliphatic hydrocarbon compounds, aliphatic alcohol-based compounds, aliphatic ether-based compounds, aliphatic diol-based compounds, aliphatic ester-based compounds, and aliphatic aldehyde-based compounds. , aliphatic ketone compounds, aliphatic carboxyl compounds, aliphatic compounds containing nitrogen atoms, aliphatic compounds containing sulfur atoms, alicyclic compounds, alicyclic compounds with heteroatoms, aromatic hydrocarbon compounds, aromatic Alcohol-based compounds, aromatic ester-based compounds, aromatic ether-based compounds, aromatic aldehyde-based compounds, aromatic carboxyl compounds, etc.

When specifically exemplifying, as an aliphatic hydrocarbon compound, n-octane, nonane, n-decane, n-undecane, etc. are mentioned. Examples of aliphatic alcohol compounds include 1-butanol, 1-pentanol, 2-pentanol, 1-hexanol, 2-hexanol, 1-heptanol, 2-heptanol, 1-octanol, 2-octanol, 2-nonanol, n-dodecane, n-tridecane, n-tetradecane, 1-nonanol, n-decyl alcohol, 2-decanol, n-undecyl alcohol, isodecanol, etc.

Examples of the aliphatic ether compound include dibutyl ether (boiling point: 137° C. to 143° C.).

Examples of aliphatic diol-based compounds include ethylene glycol, ethylene glycol monoethyl ether, ethylene glycol diethyl ether, ethylene glycol monomethyl ether, propylene glycol, propylene glycol monoethyl ether, propylene glycol monomethyl ether, hexanediol, Ethylene glycol, triethylene glycol dimethyl ether, ethylene glycol mono-2-ethylhexyl ether, ethylene glycol monobutyl ether, ethylene glycol monohexyl ether, ethylene glycol monobenzyl ether, dipropylene glycol, 1 , 3-butanediol, 1,4-butanediol, neopentyl glycol, 1,5-pentanediol, etc.

Examples of aliphatic ester compounds include: n-butyl formate, allyl acetate, n-butyl acetate, dimethyl succinate, diethyl oxalate, dimethyl oxalate, methyl lactate, ethyl lactate, acetone Methyl pyruvate, ethyl pyruvate, dimethyl malonate, diethyl malonate, etc.

Examples of the aliphatic ester compound include n-octyl acetate, diethyl succinate, and the like.

Furfural etc. are mentioned as an aliphatic aldehyde compound.

Examples of the aliphatic ketone compound include methyl isobutyl ketone, diisopropyl ketone, and diisobutyl ketone.

Examples of the aliphatic carboxyl compound include formic acid, acetic acid, and propionic acid.

Examples of aliphatic compounds containing nitrogen atoms include: N,N-dimethylacetamide, N,N-dimethylformamide, N,N-diisopropylethylamine, acetamide, etc. .

Examples of the aliphatic compound containing a sulfur atom include dimethylsulfoxide and the like.

Examples of alicyclic hydrocarbon compounds include: methylcyclohexane, dimethylcyclohexane, ethylcyclohexane, cycloheptane, decahydronaphthalene, cyclopentanol, cyclohexanol, methylcyclohexanol , Dimethylcyclohexanol, cyclohexenol, cyclohexylmethanol, tetrahydrofurfuryl alcohol, furfuryl alcohol, cyclopentanone, cyclohexanone, dioxane, methylcyclohexanone, dicyclohexyl, etc.

As an alicyclic ketone compound, isophorone etc. are mentioned.

Examples of the alicyclic lactone compound include γ-butyrolactone, δ-valerolactone, and the like.

Examples of the aliphatic carbonate compound include propylene carbonate.

Examples of the alicyclic compound containing a nitrogen atom include N-methylpyrrolidone, 2-pyrrolidone, 1,3-dimethylimidazolidone, and the like.

Examples of the alicyclic compound containing a sulfur atom include cyclobutane and the like.

Examples of aromatic hydrocarbon compounds include: toluene, o-xylene, p-xylene, m-xylene, mesitylene, 1,2,4-trimethylbenzene, ethylbenzene, o-diethylbenzene, m-diethylbenzene Ethylbenzene, p-diethylbenzene, o-ethylmethylbenzene, p-ethylmethylbenzene, m-ethylmethylbenzene, n-propylbenzene, isopropylbenzene, n-butylbenzene, second-butyl Benzene, isobutylbenzene, tert-butylbenzene, n-pentylbenzene, n-hexylbenzene, n-heptylbenzene, 1,3-di-isopropylbenzene, 1,4-di-isopropylbenzene, cyclo Hexylbenzene, tetrahydronaphthalene, etc.

Examples of aromatic alcohol compounds include: phenol, o-cresol, o-ethylphenol, m-cresol, p-cresol, p-ethylphenol, 4-methoxyphenol, o-n-propylphenol, o-isopropylphenol phenylphenol, o-second butylphenol, o-tertiary butylphenol, m-tertiary butylphenol, p-tertiary butylphenol, benzyl alcohol, etc.

Examples of the aromatic ester compound include methyl benzoate, ethyl benzoate, n-butyl benzoate, and the like.

Benzaldehyde etc. are mentioned as an aromatic aldehyde type compound.

Benzoic acid etc. are mentioned as an aromatic carboxyl compound.

As the organic solvent contained in the ink of the present embodiment, an organic solvent having a boiling point of 250° C. or higher is used. Organic solvents with such characteristics include: aliphatic hydrocarbon compounds, aliphatic alcohol-based compounds, aliphatic ether-based compounds, aliphatic diol-based compounds, aliphatic ester-based compounds, aliphatic aldehyde-based compounds, and aliphatic ketone-based compounds , Aliphatic carboxyl compounds, aliphatic compounds containing nitrogen atoms, aliphatic compounds containing sulfur atoms, alicyclic compounds, alicyclic compounds with heteroatoms, aromatic hydrocarbon compounds, aromatic alcohol compounds, aromatic Ester compounds, aromatic ether compounds, aromatic aldehyde compounds, aromatic carboxyl compounds, etc.

More specific examples of organic solvents having the aforementioned properties include triethylene glycol (boiling point 287°C), tetraethylene glycol dimethyl ether (boiling point 275°C), diethylene glycol dibutyl ether ( Boiling point 254°C), ethylene glycol monobenzyl ether (boiling point 256°C), tripropylene glycol (boiling point 268°C), 1,6-hexanediol (boiling point 250°C), thiodiglycol (boiling point 283°C), 2-(1-cyclohexenyl)cyclohexanone (boiling point 265°C), cyclobutane (boiling point 285°C), n-octylbenzene (boiling point 261°C-263°C), n-nonylbenzene (boiling point 282°C) , n-decylbenzene (boiling point 293°C), biphenyl (boiling point 255°C), dimethylnaphthalene (boiling point 261°C-287°C), n-butyl benzoate (boiling point 250°C), aromatic carboxyl compounds Phenylacetic acid (boiling point 266°C), etc.

Furthermore, as the organic solvent contained in the ink of the present embodiment, an organic solvent having a boiling point of 300° C. or higher can be used. Examples of organic solvents with such characteristics include dodecylbenzene (boiling point 331°C), diphenyl carbonate (boiling point 302°C), benzyl benzoate (boiling point 324°C), dioctyl sebacate (boiling point 312°C), dibutyl sebacate (boiling point 349°C), dibutyl phthalate (boiling point 341°C), dioctyl phthalate (boiling point 361°C), nonylphenol (boiling point 303°C) , p-benzylphenol (boiling point 320°C), diphenylsulfone (boiling point 379°C), etc.

The ink composition according to this embodiment only needs to contain one or more organic solvents having a boiling point of 250° C. or higher, and it is preferable to use a mixture of a plurality of organic solvents in consideration of adjustment of physical properties of the ink.

From the viewpoint of calculating the ejection amount from the image captured by the camera 31 and from the viewpoint of film-forming properties, the organic solvent contained in the ink composition according to this embodiment has a boiling point of 250° C. or higher relative to the weight of the composition The content of is preferably more than 20% by weight. The reason for this is that, when the content of the organic solvent having the above characteristics is small, errors in imaging when measuring the ejection amount of the ink tend to occur.

In addition to the organic solvent, the ink composition may suitably contain additives such as a surfactant for surface adjustment, a UV absorber for storage stability of the ink composition, a light stabilizer, and an antioxidant.

The boiling point of the organic solvent contained in the ink composition of this embodiment is 250° C. or higher, preferably 280° C. or higher, more preferably 300° C. or higher. The upper limit is preferably at most 400°C, more preferably at most 380°C, particularly preferably at most 350°C. This is the boiling point of the environment in which the display panel D is manufactured using the inkjet device 1 of the present embodiment. That is, the drying conditions of the ink are assumed. Therefore, the type and boiling point temperature of the high-boiling organic solvent to be used can be changed or adjusted according to the usage environment (measurement environment) of the inkjet device 1 .

The ink composition according to the present embodiment containing an organic solvent having a boiling point of 250° C. or higher is preferably used in the production of the display panel D itself. That is, the display panel D is directly manufactured by using the ink for adjusting the ejection amount of ink from the inkjet head 23 of the inkjet device 1 to an appropriate ejection amount through the ejection step, the acquisition step, and the derivation step It is preferable that the process can be quickly transferred to the panel manufacturing step in a state where the ejection amount of ink from the inkjet head 23 is the optimum ejection amount. After the ejection step, the acquisition step, and the derivation step, the ink used to adjust the ejection amount of ink from the inkjet head 23 of the inkjet device 1 to an appropriate ejection amount is different from the ink used for panel manufacturing In some cases, in order to replace the ink, a cleaning step or an ink replacement step is required. Therefore, there is a problem that it takes time to increase panel manufacturing costs, or that the nozzles of the inkjet device 1 are loaded due to the cleaning step or replacement step, and the ink ejection amount may deviate from the adjusted ejection amount.

[Flow of Injection Quantity Measurement Adjustment Procedure] The ejection amount measurement adjustment step is performed by the ink ejection amount measurement adjustment device having the inkjet device 1 . The injection amount measurement adjustment step has a measurement adjustment method shown below.

[measurement adjustment method] The measurement adjustment method includes a measurement method of measuring the droplet volume of ink ejected from the inkjet head 23 described below. When the droplet volume of the ink measured by the measurement method deviates from an appropriate value, an adjustment method for adjusting to an appropriate value is required. Therefore, the measurement adjustment method of the present embodiment may include a measurement step of measuring the ejection amount of ink, and an adjustment step of performing adjustment based on the measurement result in the measurement step.

[Measurement methods] Next, a method of measuring the ejection amount of ink (hereinafter, also referred to as “measurement method”) using the inkjet device 1 according to the present embodiment will be described. The measurement method of the present embodiment is at least a necessary method for adjusting the ejection amount of ink by the inkjet device 1 according to the present embodiment. The measurement method of the present embodiment refers to a method of measuring the ejection amount of ink from the inkjet head 23. Here, the droplet amount of the ink ejected from the inkjet head 23 is not directly measured, but by the following steps S602 to S605. A series of steps in the process to measure indirectly.

6 is a flowchart of the injection amount measurement and adjustment step according to the present embodiment, and is a flowchart showing an example of the flow of the injection amount measurement step and the injection amount adjustment step according to the present embodiment described below. As shown in FIG. 6, the injection amount measurement adjustment step includes a plurality of steps. Each step shown in FIG. 6 may be started based on a user's instruction, or may be started based on a predetermined operation condition. In addition, in order to simplify description, it assumes that the flow of each of the following steps is fully controlled by the control apparatus 50, and it demonstrates.

(insert step) When measuring the ejection amount of ink from the inkjet head 23, first, as an insertion step of the base material B1, the base material B1 is inserted to a predetermined start position. In S601, the control device 50 inserts the substrate B1 for ejection amount measurement after controlling the position of each part to the start position of the main measurement step described below. It is assumed that the start position of the measurement procedure in this embodiment is the position of the stage 40 shown in FIG. 1 . At this position, the base material B1 is in a state where it can be inserted onto the stage 40 . Moreover, as shown in FIG. 2, the inkjet head 23 is also set to be located on the conveyance path of the base material B1. In addition, the insertion of the base material B1 into the stage 40 can be performed using the insertion apparatus (not shown) etc. which are provided separately.

(spray step) The ejecting step is a step of ejecting ink from the inkjet head 23 onto the substrate B1, and landing the ink on the substrate B1. In S602, as shown in FIG. 7, the control apparatus 50 moves the base material B1 directly below the inkjet head 23, and ejects ink on the base material B1. The ejection of the ink here may be performed simultaneously in all of the plurality of inkjet heads 23 , or may be performed sequentially in a predetermined order. In addition, at the time of spraying, a spray pattern such as spraying from all the nozzles at the same time may be used, or a predetermined spray pattern that sprays sequentially to each nozzle may be used. As described above, since the surface of the substrate B1 is coated with the liquid-repellent coating material, the ejected ink droplets 202 have a dome-like shape as shown in FIG. 9A . Here, the ink droplet which landed on the base material B1 is represented as K.

(drying step) The drying step is a step of stabilizing the ink for a certain period of time in order to almost eliminate the volume change caused by the drying of the organic solvent contained in the ink dropped on the substrate B1 in the spraying step. In S603, the control device 50 performs drying of the ink droplets K on the substrate B1 as shown in FIG. 9A. As mentioned above, the ink of this embodiment contains the organic solvent (high boiling point solvent) which does not evaporate easily. Therefore, by providing a drying step for a certain period of time after landing on the substrate B1, the volume of the ink droplet K is stabilized after a certain degree of evaporation of the ink occurs. In the stabilized state, the diameter of the ink droplet K does not change substantially. In this state, the volume change of the ink almost disappears, and a constant ratio is maintained. By imaging the ink droplet K after stabilizing the volume of the ink as described above, the amount of the ink droplet can be accurately measured. The time required for this drying step is determined according to the characteristics of the ink. For example, in the case of having the characteristics shown in FIG. 4 or FIG. 5 , the time required for the drying step is preferably 5 minutes or longer, more preferably 10 minutes or longer, as a predetermined time. In addition, as shown in FIG. 1 , when a plurality of inkjet heads 23 are included and each corresponds to inks of different compositions, the drying time in the drying step in S603 is also adjusted according to the composition of each ink.

The form of the drying step is not particularly limited, as long as a predetermined time can be set to the imaging step described later. For example, drying may be performed with the base material B1 stopped directly under the inkjet head 23 , or may be a method in which a predetermined time elapses while moving to the imaging position of the camera 31 . Alternatively, drying may be performed at the shooting position of the camera 31 . In addition, in this embodiment, drying is set as natural drying, without performing special temperature or humidity adjustment, and measuring the drying time in the period during which drying is performed at least.

(acquisition steps) The acquiring step is a step of acquiring an image of the ink ejected onto the substrate B1. In S604 , as shown in FIG. 8 , the control device 50 moves the substrate B1 directly below the camera 31 to photograph the substrate B1 and obtain an image including the ink jetted onto the substrate B1 . FIG. 8 is a schematic diagram showing a state of the substrate B1 when it is photographed. 9A is a view of the surroundings of the camera 31 at the time of imaging as viewed from the side along the X-axis direction, and FIG. 9B is a view of the base material B1 to be photographed as viewed from the upper surface side along the Z-axis direction. In addition, although the example which imaged the ink droplet K for every line (line) of a sub-scanning direction was shown in FIG. 8, FIG. 9A, and FIG. 9B, it is not limited to this. According to the angle of view or resolution of the camera 31 , multiple rows of ink droplets K can be collectively photographed. From the viewpoint of shortening the time, it is preferable to use a high-angle, high-resolution camera to collect and shoot a plurality of ink droplets K in one shot, and it is best to shoot all the ink liquid sprayed onto the substrate B1 in one shot. Drop K.

(export step) The derivation step is a step of deriving the ejection amount of the ink ejected from the nozzles of the inkjet head 23 to each nozzle based on the information obtained in the acquisition step of S604. In S605, the control device 50 calculates the ejection amount of ink from each nozzle based on the image captured in S604. Specifically, the control device 50 specifies the range of the ink droplet K ejected from each nozzle based on the image, and derives the diameter of the ink droplet K. Furthermore, the control device 50 derives the ejection amount of the ink from the derived diameter of the ink droplet K.

In this embodiment, based on the diameter of the ink droplet K, the ejection amount of the ink is derived. Since the base material B1 is coated with a liquid-repellent coating material, the ink does not bleed into the base material B1. On the other hand, through the drying step of S603, the ink is dried, and its volume will change by a certain amount. As shown in FIG. 4 , the volume of the ink of this embodiment is stable after a certain amount of drying. Therefore, the ejection amount of ink ejected from the nozzles can be derived based on the stabilized ink volume and the change ratio of the ink volume according to the composition of the ink. Note that the time until the volume of the ink is stabilized due to drying varies depending on the composition of the ink or the surrounding environment, so it is not limited to the above. In the present embodiment, it is preferable that the surrounding environment (temperature or humidity) is constant when the organic EL display panel is manufactured.

In this embodiment, first, a table (not shown) for deriving the volume of the ink droplet K from the diameter of the ink droplet K on the substrate B1 is used. The diameter of the ink droplet K on the substrate B1 coated with the liquid-repellent coating material varies not only with the amount of ink but also with the surface tension or contact angle specified by the composition of the ink. Therefore, a table defining the relationship between the diameter and the volume on the base material B1 is used corresponding to the ink used. Furthermore, the method of deriving the volume of the ink droplet K from the diameter of the ink droplet K is not limited thereto. For example, a formula corresponding to the ink composition may be predetermined, and the volume may be calculated from the diameter of the ink droplet K using the formula.

The control device 50 derives the ejection amount of ink for all the nozzles included in the inkjet head 23 . Furthermore, in this step, the control device 50 may be configured to perform image processing on the image captured by the camera 31 . For example, in order to detect the diameter of the ink droplet K more accurately, it may be configured to perform edge processing, filter processing, or the like. Through each step of S602 to S605 so far, the ejection amount of ink is measured.

[adjustment method] The measurement adjustment method of the present embodiment is preferably an adjustment method having an adjustment procedure described below after implementing the measurement method including the above-mentioned measurement procedure. In the present embodiment, the ejection amount of the ink carried out by the inkjet device 1 is measured by the measuring method having the above-mentioned measuring steps. As a result, when the ejection amount of the ink deviates from an appropriate value, it is necessary to adjust the ejection amount of the ink to Adjustment steps for appropriate values. Furthermore, the ejection amount of ink by the inkjet device 1 is measured by the measuring method having the measuring step, and as a result, if the ejection amount of ink is an appropriate value, the adjustment step is not required.

(adjustment steps) The adjusting step is a step of adjusting the ejection amount of the ink from the inkjet head 23 derived in the measuring step ( S602 to S605 ) to an appropriate amount. In S606, the control device 50 adjusts the ejection amount of ink from the corresponding nozzle to an appropriate amount based on the ejection amount of ink derived in S605. The adjustment here may include detection of nozzles that do not eject ink, in addition to increasing or decreasing the ejection amount of ink.

(discharging step) In S607, the control device 50 discharges the base material B1. The discharge position of the base material B1 may be the same as the insertion position of the base material B1, and may be downstream in the conveyance direction of the base material B1. In addition, discharge|emission of the base material B1 from the stage 40 can be performed using the discharge apparatus (not shown) etc. which are provided separately. Usually, the formal discharge step is performed after the final step of the measurement step or the adjustment step, that is, the measurement step and the adjustment step are normally completed. Then, the flow of the main injection amount measurement adjustment step is ended.

In the above example, each nozzle of the inkjet head 23 is configured to measure the ejection amount of ink and adjust the ejection amount by one ejection. The measurement and adjustment method of this embodiment is not limited to this configuration, but can be configured to improve the accuracy of the adjustment by repeating the steps of S602 to S606 multiple times. In addition, a configuration may be adopted in which, when a nozzle that does not eject ink occurs as a result of the adjustment, information related to the nozzle is notified.

When repeating the steps of S602-S606 multiple times, it is preferable to finish in a short time, and it is preferable that the number of times of repeating the steps of S602-S606 is small. The number of repetitions is usually ten or less, preferably five or less, more preferably three or less, particularly preferably two or less, and most preferably once in terms of a short time. From the viewpoint of performing the steps of S602 to S606 once and checking the amount of ink ejected from the inkjet head 23, it is preferable to perform the steps once more, twice. In the case of performing it twice or more, if the ejection amount of the ink derived in the measurement step after the second time is an appropriate value, the next step of S606 may not be carried out.

In addition, when the panel manufacturing is to use the same type of ink to manufacture the same type of panel for a long time, due to the accumulation of data in the measurement steps and adjustment steps, a series of measurement steps and adjustment steps in S602~S606 can be Only once, from the point of view of confirming the ejection amount of ink from the inkjet head 23 after the adjustment step, it is preferable to perform another measurement step after the series of measurement steps and adjustment steps in S602˜S606. In addition, if the ejection amount of the ink from the inkjet head 23 derived in the measurement step is an appropriate amount, the adjustment step is unnecessary. In this case, the process may proceed to the discharge step of the next base material B1, or the measurement step may be performed again to reconfirm that the ejection amount of the ink from the inkjet head 23 is an appropriate amount.

If the ejection amount of the ink from the inkjet head 23 derived in the measurement step is an appropriate amount, it is preferable not to perform the measurement step again from the viewpoint of shortening the entire time of the ejection amount measurement adjustment step. The process proceeds to the step of discharging the next base material B1 ( S607 ). On the other hand, when the ejection amount of the ink from the inkjet head 23 derived in the measurement step is an appropriate amount, the measurement step is performed again to reconfirm that the ejection amount of the ink from the inkjet head 23 is an appropriate amount. When it is used, it is possible to confirm that there is no fluctuation or error in the injection amount due to unexpected disturbing factors, and it is possible to perform manufacturing with a higher yield, which is preferable from the point of view.

In the measurement step, since a certain amount of time is required in the drying step ( S603 ), when the measurement step is repeated a plurality of times, it takes a long time, which is not preferable in terms of production. Therefore, in the measuring step, it is preferable to spray a plurality of ink droplets from one nozzle to different positions on the substrate B1 to perform the measuring step. According to this method, even if a plurality of injections are performed, the influence of fluctuations or errors in the injection amount due to unexpected disturbance factors can be reduced in one measurement step, which is preferable. In addition, when the measurement step for confirmation is performed again after the subsequent adjustment step ( S606 ), it is preferable to similarly eject a plurality of ink droplets from one nozzle to different positions on the base material B1 .

As mentioned above, the ink of this embodiment contains a high boiling point solvent. The high boiling point solvent does not evaporate at room temperature (ie, under the manufacturing environment of the display panel D), so the change in the diameter of the ink droplet K almost disappears after the solvent becomes only the high boiling point solvent. Therefore, the diameter of the ink droplet K of the high boiling point solvent can be accurately measured from the captured image. If the content of the high-boiling-point solvent in the ink is accurately measured in advance, the ink ejection droplet volume can be accurately converted from the diameter of the ink droplet K. As a result, the measurement of the ejection amount per nozzle of the inkjet head 23 can be appropriately performed. Furthermore, the ejection amount of the nozzles of the inkjet head 23 can be appropriately adjusted, and when the ink is ejected to the substrate B2 during the manufacture of the display panel D, natural drying can also be suppressed due to the influence of the high boiling point solvent. As a result, when the display panel D is manufactured, the drawing process with respect to the base material B2 can be performed suitably without film thickness unevenness.

[Relationship between injection amount measurement adjustment procedure and panel manufacturing procedure] The panel manufacturing system for an organic EL display panel according to this embodiment includes the ink ejection amount measurement and adjustment device, and an organic EL display panel manufacturing device including an inkjet head 23 using the ink ejection amount measurement and adjustment device. After the ejection amount measurement and adjustment step shown in FIG. 6 is completed, the organic EL display panel is manufactured. In this case, the base material B2 is inserted into the stage 40 instead of the base material B1, and panel manufacture is performed. Since the ejection amount of ink also varies depending on, for example, the batch of the inkjet head 23, it is necessary to use the inkjet head 23 that has completed the ejection amount measurement and adjustment step shown in FIG. 6 in the manufacture of the organic EL display panel. Furthermore, the timing for performing the adjustment actions shown in FIG. 6 can be arbitrary. For example, it may be performed before the first base material B2 in the batch unit in the manufacture of organic EL display panels. Alternatively, it can also be carried out on each substrate B2 when manufacturing an organic EL display panel. In addition, in the case where a plurality of inkjet heads 23 are provided corresponding to each of the layers constituting the organic EL display panel, the ejection amount measurement and adjustment step of FIG. 6 can be performed on each of the inkjet heads 23 corresponding to each layer. , the ejection amount measurement and adjustment step in FIG. 6 may also be collectively performed on the inkjet heads 23 corresponding to each layer.

In addition, after replacing or cleaning the inkjet head 23 , it is also necessary to perform the ejection amount measurement adjustment step shown in FIG. 6 . This is because, when the inkjet head 23 is replaced, it is necessary to initially adjust all the nozzles of the inkjet head 23 . And because, in the case of cleaning, accidents, minor deformations of parts below the detection limit and/or undetectable parts, minor deviations of parts, etc., may affect the variation in the ejection amount of ink. Furthermore, even with the same type of ink, when the ink is replaced by some method, it is necessary to perform the ejection amount measurement and adjustment step shown in FIG. 6 . The reason is that even with the same type of ink, slight fluctuations in the liquid physical properties of the ink, such as when the batches are different, may affect the fluctuation in the ejection amount from the inkjet head 23 .

As above, the ejection amount of ink may also vary depending on the batch of ink or the replacement of ink. Therefore, in the manufacture of organic EL display panels, it is preferable to directly use the ink that has completed the ejection amount measurement and adjustment steps shown in FIG. 6 . ink. Also, directly using the ink that has been subjected to the ejection amount measurement adjustment step shown in FIG. 6 represents the following state. That is, the ink ejected from the plurality of nozzles provided on the inkjet head 23 is usually stored in an ink storage unit (not shown) mounted on the inkjet head 23 or an ink connected to the inkjet head 23 through piping. portion (not shown) is continuously supplied to the inkjet head 23 . Direct use of the ink that has been subjected to the ejection amount measurement and adjustment step shown in FIG. 6 means that the ink is directly used for panel manufacturing without resupply and replacement of ink to the ink storage part after the ejection amount measurement adjustment step shown in FIG. 6 is completed. step. Thereby, after the ejection amount measurement and adjustment step shown in FIG. 6 is completed, it is possible to move to the panel manufacturing step without slight fluctuations in the physical properties of the ink, so that the inkjet head 23 adjusted to an appropriate ejection amount can be stabilized. It is better to carry out panel manufacturing in a timely manner.

Moreover, it is described here as "the injection quantity measurement and adjustment step shown in Fig. 6], but it is only the title of the step, and does not use its sentence to express the content of the step. That is, in the measurement step (S602 ~ S605 ) The case where the adjustment step ( S606 ) is not performed when it is confirmed that the injection amount is appropriate is also included in the "injection amount measurement adjustment step shown in FIG. 6 ".

[Structure of Display Panel D] Next, a display panel D that can be manufactured using the method for measuring or adjusting the amount of ink ejection described above will be described with reference to FIGS. 10 to 12 . FIG. 10 is a schematic plan view of a structural example of a display panel D according to this embodiment. Since FIG. 10 is a schematic diagram, its scale may be different from the actual one.

The display panel D of the present embodiment is an organic EL display panel utilizing the electroluminescence phenomenon of organic compounds. The display panel D has a top-emission structure, that is, on a substrate on which thin film transistors (TFTs) are formed (hereinafter referred to as "TFT substrate"), a plurality of organic EL display elements constituting pixels are arranged in a matrix, and Light is emitted from the upper surface (color filter substrate 131 side). Here, the X direction, the Y direction and the Z direction in FIG. 10 are also referred to as the column direction, the row direction and the thickness direction of the display panel D, respectively.

As shown in FIG. 10 , the display panel D of this embodiment is composed of a partitioned area 10 a and a non-segmented area 10 b located around 10 a. The partitioned area 10 a is partitioned into a matrix on the substrate 100 by the banks 122 that limit the light-emitting units of each color (here, three colors of RGB). In addition, the description will be made assuming that the banks 122 along the Y-axis direction are referred to as row banks 122Y, and the banks along the X-axis direction are referred to as column banks 122X.

In the non-divided area 10b, a rectangular sealing member 300 surrounding the divided area 10a is formed. The partitioned area 10a includes a display pixel arrangement area 10e including the center of the substrate 100, and a non-light-emitting area 10ne located around the display pixel arrangement area 10e. The display pixel array region 10e is a region where organic EL display elements are formed in each section defined by the row bank 122Y and the column bank 122X. On the other hand, the non-light emitting region 10ne is a region where no organic EL display element is formed.

FIG. 11 is an enlarged plan view of a part of the display pixel arrangement region 10 e shown in FIG. 10 . In the display pixel array region 10e, unit cells 100e corresponding to organic EL display elements are arranged in a matrix. The unit cell 100e is a region that emits light by an organic compound. In this example, the unit element 100e includes self-emitting regions 100a corresponding to three colors: a self-emitting region 100aR emitting red (R) light, a self-emitting region 100aG emitting green light, and a self-emitting region 100aB emitting blue light.

In addition, as shown in FIG. 11 , a plurality of pixel electrodes 119 are arranged on the substrate 100 with a predetermined distance apart in the column direction and the row direction. The pixel electrodes 119 arranged in a matrix correspond to the self-emitting regions 100aR, 100aG, and 100aB arranged sequentially in the column direction. In addition, the region other than the self-luminous region 100a is the non-self-luminous region 100b. A contact hole 119c connecting the pixel electrode 119 and the source of the TFT is provided in the non-self-luminous region 100b. Furthermore, a contact region 119b for electrically connecting with the pixel electrode 119 is provided in the non-self-luminous region 100b.

Fig. 12 is a schematic cross-sectional view of a position cut at X1-X1 shown in Fig. 11 . As shown in FIG. 12 , the display panel D according to this embodiment is composed of a substrate 100 (TFT substrate) on which thin film transistors are formed below the Z-axis direction, and an organic EL element portion as a light emitting element portion is formed on the substrate 100 . The organic EL element portion includes a plurality of layers, and the above-mentioned inkjet device 1 can be applied when forming a part thereof. The plurality of layers constituting the organic EL element portion include a pixel electrode 119, a hole injection layer 120, a hole transport layer 121, a bank 122, a light emitting layer 123, an electron transport layer 124, a counter electrode 125, a sealing layer 126, The bonding layer 127 and the color filter substrate 131 . In addition, the color filter substrate 131 is configured including the color filter layer 128 and the upper substrate 130 . Hereinafter, parts constituting the display panel D will be described.

(substrate (TFT substrate)) The substrate 100 is a supporting member of the display panel D, and has a base material (not shown), a thin film transistor (TFT) layer (not shown) formed on the base material, and an interlayer formed on the base material and the TFT layer. insulation (not shown).

A base material (not shown) constituting the substrate 100 is a support member of the display panel D and is flat. As the material of the base material, an electrically insulating material such as a glass material, a resin material, a semiconductor material, a metal material coated with an insulating layer, or the like can be used. For example, metal substrates such as glass substrates, quartz substrates, silicon substrates, molybdenum sulfide, copper, zinc, aluminum, stainless steel, magnesium, iron, nickel, gold, silver, semiconductor substrates such as gallium arsenide, and plastic substrates can be used as substrates. .

The TFT layer (not shown) constituting the substrate 100 includes a plurality of TFTs and wiring formed on the upper surface of the substrate. According to the driving signal from the external circuit of the display panel D, the TFT electrically connects the pixel electrode 119 corresponding to itself with an external power source (not shown), including multi-layer structures such as electrodes, semiconductor layers, and insulating layers. The wiring (not shown) electrically connects the TFT, the pixel electrode 119 , an external power source, an external circuit, and the like. The interlayer insulating layer located on the upper surface of the substrate 100 is an interlayer insulating layer that planarizes at least a part of the upper surface of the substrate 100 having unevenness by the TFT layer. In addition, the interlayer insulating layer fills between the wiring and the TFT, and electrically insulates the wiring and the TFT.

For example, silicon dioxide (SiO 2 ), silicon nitride (SiN), silicon oxynitride (SiON), silicon oxide (SiO), and silicon oxynitride (SiON) can be used in the interlayer insulating layer. As the connection electrode layer of the TFT, for example, a laminate of molybdenum (Mo), copper (Cu), and copper manganese (CuMn) can be used. The interlayer insulating layer is formed using, for example, organic compounds such as polyimide resin, acrylic resin, siloxane resin, and novolac phenolic resin, and the thickness of the layer may be in a range of, for example, 2000 nm to 8000 nm.

(pixel electrode) A pixel electrode 119 is disposed on an interlayer insulating layer (not shown) located on the upper surface of the substrate 100 . The pixel electrode 119 is used to supply carriers to the light emitting layer 123 , for example, to supply holes to the light emitting layer 123 when functioning as an anode. The pixel electrode 119 has a rectangular flat plate shape. In addition, through a contact hole opened on the upper surface of the substrate 100, the connection recess of the pixel electrode 119, in which a part of the pixel electrode 119 is recessed along the direction of the substrate 100, is connected to the source of the TFT.

The pixel electrode 119 includes a metal material. In the case of a top-emission organic EL display panel, by setting an optimum layer thickness and adopting an optical resonator structure, it is possible to adjust the chromaticity of emitted light and improve brightness. Therefore, the surface portion of the pixel electrode 119 has high reflectivity. The pixel electrode 119 may also have a structure in which a plurality of films selected from a metal layer, an alloy layer, and a transparent conductive film are laminated. As the metal layer, for example, a metal material including silver (Ag) or aluminum (Al) may be included. As the alloy layer, for example, APC (alloy of silver, palladium, and copper), ARA (alloy of silver, rubidium, and gold), MoCr (alloy of molybdenum and chromium), NiCr (alloy of nickel and chromium), etc. can be used. As a constituent material of the transparent conductive layer, for example, indium tin oxide (ITO), indium zinc oxide (IZO), or the like can be used.

(hole injection layer, hole transport layer) A hole injection layer 120 and a hole transport layer 121 are sequentially stacked on the pixel electrode 119 , and the hole transport layer 121 is in contact with the hole injection layer 120 . These two layers have the function of transporting holes injected from the pixel electrode 119 to the light emitting layer 123 .

The hole injection layer 120 is, for example, an oxide containing silver (Ag), molybdenum (Mo), chromium (Cr), vanadium (V), tungsten (W), nickel (Ni), iridium (Ir), or a conductive Layers of polymer material.

As the conductive polymer material that can be used as the hole injection layer 120 or the hole transport layer 121, it can be exemplified: polyvinylcarbazole or its derivatives, polysilane or its derivatives, and aromatic compounds in the side chain or main chain. polysiloxane derivatives of amines, pyrazoline derivatives, arylamine derivatives, toluene derivatives, triphenyldiamine derivatives, polyaniline or its derivatives, polythiophene or its derivatives, Polypyrrole or its derivatives, poly(p-phenylene vinylene) or its derivatives, or poly(2,5-thienyl vinylene) or its derivatives, etc. Specifically, the hole transport material can be exemplified in Japanese Patent Application Laid-Open No. 63-70257, Japanese Patent Application Laid-Open No. 63-175860, Japanese Patent Application Laid-Open No. 2-135359, Japanese Patent Laid-Open No. 2-135361, Japanese Patent Application Laid-Open No. 2-135361, Those described in Japanese Patent Laid-Open No. 2-209988, Japanese Patent Laid-Open No. 3-37992, and Japanese Patent Laid-Open No. 3-152184.

Among them, as the hole transporting material used in the hole transporting layer 121, polyvinylcarbazole or its derivatives, polysilane or its derivatives, compounds having aromatic amines in the side chain or the main chain are preferable. based polysiloxane derivatives, polyaniline or its derivatives, polythiophene or its derivatives, poly(p-phenylene vinylene) or its derivatives, or poly(2,5-thienyl vinylene) or its derivatives Polymer hole-transporting materials such as materials, preferably polyvinylcarbazole or its derivatives, polysilane or its derivatives, and polysiloxane derivatives with aromatic amines in the side chain or main chain. In the case of a low-molecular hole transport material, it is preferably dispersed in a polymer binder for use.

Polyvinylcarbazole or its derivatives are obtained, for example, from vinyl monomers by cationic polymerization or radical polymerization. Polysiloxane or its derivatives can be preferably used in those having the above-mentioned hole transport material in the side chain or main chain in the siloxane skeleton structure. In particular, aromatic amines having hole transport properties in side chains or main chains can be exemplified.

The hole injection layer 120 and the hole transport layer 121 can be formed using the inkjet device 1 shown in FIG. 1 . The ink used to form any of these layers is not particularly limited as long as the organic solvent used can dissolve the hole injection material or the hole transport material.

(Bank) The bank 122 including an insulator is formed so as to cover the edges of the pixel electrode 119 , the hole injection layer 120 , and the hole transport layer 121 . The bank 122 is to prevent current leakage in the thickness direction (Z-axis direction) between the outer edge of the pixel electrode 119 and the counter electrode 125 , and ideally has insulation with a volume resistivity of 1×10 ⁶ Ωcm or more.

The bank 122 is formed using an organic material such as resin, and has insulating properties. Examples of organic materials used to form the banks 122 include acrylic resins, polyimide resins, novolak-type phenolic resins, and the like. The banks 122 are preferably resistant to organic solvents. More preferably, an acrylic resin is used. This is because acrylic resin is preferable as a reflector due to its low refractive index.

When an inorganic material is used for the bank 122 , silicon oxide (SiO), for example, is preferably used from the viewpoint of the refractive index. Alternatively, the bank portion 122 may be formed using inorganic materials such as silicon nitride (SiN), silicon oxynitride (SiON), and the like.

Furthermore, the bank portion 122 is sometimes subjected to etching treatment, baking treatment, etc. during the panel manufacturing process, and thus is preferably formed of a highly resistant material that does not cause excessive deformation, deterioration, etc. due to these treatments. In addition, in order to make the surface liquid-repellent, the surface of the bank 122 may be treated with fluorine by chemical vapor deposition (CVD) or the like.

(luminous layer) On the display panel D is formed a light emitting layer 123 that emits light of various colors. The colors here specifically include three colors of red (R), green (G), and blue (B). The light emitting layer 123 is a layer containing an organic compound, and has a function of emitting light by recombining holes and electrons inside. The light emitting layer 123 emits light only in the portion supplied with carriers from the pixel electrode 119 . The light emitting layer 123 can be formed using the inkjet device 1 shown in FIG. 1 .

As a material for forming the light-emitting layer 123, a light-emitting organic material that can be formed into a film by a wet printing method must be used. The light emitting layer 123 is not particularly limited as long as it is made of a known material that can be used as a light emitting layer (a layer having a light emitting function) of an organic EL element portion, and the material thereof is not particularly limited, but is preferably a layer containing an organic material. luminous layer. For example, it is preferable to form a layer formed of a fluorescent or phosphorescent organic substance (low-molecular compound and high-molecular compound) as a light-emitting material, and a dopant assisting it.

Examples of such light-emitting materials (organic substances that emit fluorescence or phosphorescence) include dye-based materials, metal complex-based materials, polymer-based materials, and the like. Examples of such pigment-based materials include cyclopentamine derivatives, tetraphenylbutadiene derivatives, triphenylamine derivatives, oxadiazole derivatives, and pyrazoloquinoline derivatives. , distyrylbenzene derivatives, distyryl aryl derivatives, pyrrole derivatives, thiophene ring compounds, pyridine ring compounds, perionone derivatives, perylene derivatives, oligothiophene derivatives, oxadiazole di polymers, pyrazoline dimers, etc.

In addition, examples of metal complex materials include aluminum quinoline complexes, benzoquinoline beryllium complexes, benzoxazolyl zinc complexes, benzothiazole zinc complexes, Azomethyl zinc complexes, porphyrin zinc complexes, europium complexes, etc. have aluminum (Al), zinc (Zn), beryllium (Be), etc. or uranium (Tb), europium (Eu) in the center metal , dysprosium (Dy) and other rare earth metals and metal complexes with oxadiazole, thiadiazole, phenylpyridine, phenylbenzimidazole, quinoline structure, etc. in the ligand.

Furthermore, examples of polymer materials include polyphenylene vinylene derivatives, polythiophene derivatives, polyparaphenylene derivatives, polysilane derivatives, polyacetylene derivatives, polyfluorene derivatives, and polyvinylcarbazole derivatives. substances, those obtained by polymerizing the above-mentioned chromophores or metal complex-based light-emitting materials, and the like.

Among such light-emitting materials, materials that emit blue light include: distyryl aryl derivatives, oxadiazole derivatives, and polymers thereof, polyvinylcarbazole derivatives, polypara Benzene derivatives, polyfluorene derivatives, etc. Among them, polyvinylcarbazole derivatives, polyparaphenylene derivatives, polyfluorene derivatives, etc., which are polymer materials, are preferable.

In addition, examples of light-emitting materials that emit green light include quinacridone derivatives, coumarin derivatives, and polymers thereof, polyphenylene vinylene derivatives, polyfluorene derivatives, and the like. Among them, poly(p-phenylene vinylene derivatives), polyfluorene derivatives, and the like are preferable as polymeric materials.

In addition, examples of light-emitting materials that emit red light include coumarin derivatives, thiophene ring compounds, and polymers thereof, polyphenylene vinylene derivatives, polythiophene derivatives, and polyfluorene derivatives. Among them, polyparaphenylene vinylene derivatives, polythiophene derivatives, polyfluorene derivatives, and the like are preferable as polymeric materials.

In addition, the method for producing such a luminescent material is not particularly limited, and a known method can be suitably used, for example, the method described in Japanese Patent Laid-Open No. 2012-144722 can be used.

In addition, for the purpose of improving luminous efficiency or changing the luminous wavelength, it is preferable to add a dopant to the ink used when forming the luminous layer 123 . Examples of such dopants include perylene derivatives, coumarin derivatives, rubrene derivatives, quinacridone derivatives, squarylium salt derivatives, porphyrin derivatives, styryl Pigments, condensed tetraphenyl derivatives, pyrazolone derivatives, decacyclene, phenoxazinone, etc. Furthermore, the thickness of the light-emitting layer 123 is preferably generally about 20 Ř2000 Å.

By using an ink containing a high-boiling-point organic solvent at 250° C. or higher, preferably 300° C. or higher, the film shape of the formed light-emitting layer 123 is similarly formed in a shape in which the film thickness is equal between the peripheral portion and the central portion of the film-forming region. . That is, with the ink of this embodiment, it is possible to suppress film thickness variation due to an imbalance in the solvent evaporation rate accompanying the vapor concentration distribution of the ink solvent between the central portion and the peripheral portion of the substrate.

(electron transport layer) On the bank 122 and in openings defined by the bank 122 , an electron transport layer 124 is formed on the light emitting layer 123 , and has a function of transporting electrons injected from the counter electrode 125 to the light emitting layer 123 . The electron transport layer 124 is formed using, for example, oxadiazole derivatives (OXD), triazole derivatives (TAZ), phenanthroline derivatives (BCP, Bphen), and the like.

(Electrode) The counter electrode 125 is laminated so as to cover the electron transport layer 124 . The counter electrode 125 may be formed in a continuous state on the entire display panel D, and may be connected to bus bar wiring in units of pixels or in units of several pixels (not shown). The counter electrode 125 sandwiches the light-emitting layer 123 in a pair with the pixel electrode 119 , forms a conduction path, and supplies carriers to the light-emitting layer 123 . For example, when functioning as a cathode, the counter electrode 125 supplies electrons to the light emitting layer 123 . The counter electrode 125 is formed along the surface of the electron transport layer 124 , and is an electrode common to each of the light emitting layers 123 formed between the banks 122 . A light-transmitting conductive material is used for the counter electrode 125 . For example, the counter electrode 125 is formed using indium tin oxide (ITO), indium zinc oxide (IZO), or the like. In addition, an electrode obtained by thinning silver (Ag) or aluminum (Al) may also be used as the counter electrode 125 .

(sealing layer) The sealing layer 126 is laminated so as to cover the counter electrode 125 and prevents the light emitting layer 123 from deteriorating due to contact with moisture or air. The sealing layer 126 is provided on the entire surface of the display panel D so as to cover the upper surface of the counter electrode 125 . The sealing layer 126 is formed using a light-transmitting material such as silicon nitride (SiN), silicon oxynitride (SiON), and the like. In addition, a sealing resin layer including a resin material such as acrylic resin or silicone resin may be provided on a layer formed using materials such as silicon nitride (SiN) and silicon oxynitride (SiON).

(joint layer) A color filter substrate 131 including an upper substrate 130 and a color filter layer 128 is disposed above the sealing layer 126 in the Z-axis direction, and the sealing layer 126 and the color filter substrate 131 are bonded by the bonding layer 127 . The bonding layer 127 has a function of bonding the back panel including layers from the substrate 100 to the sealing layer 126 to the color filter substrate 131 and preventing the layers from being exposed to moisture or air. The material of the bonding layer 127 can be transparent resin materials such as acrylic resin, silicone resin, epoxy resin, etc., for example.

(upper substrate) In the upper substrate 130 constituting the color filter substrate 131 , since the display panel D is a top emission type, light-transmitting materials such as cover glass and transparent resin film can be used, for example. In addition, the display panel D can use the upper substrate 130 to improve rigidity, prevent intrusion of moisture or air, and the like. As the translucent material, for example, a glass substrate, a quartz substrate, a plastic substrate, or the like can be used.

(color filter layer) On the color filter substrate 131 , the color filter layers 128 corresponding to the respective colors are formed at positions corresponding to light emitting regions of pixels. The light emitting area corresponds to the position of the light emitting layer 123 formed between the banks 122 . The color filter layer 128 is a transparent layer provided for transmitting visible light of a wavelength corresponding to each color (for example, R, G, B), and has a function of transmitting light emitted from each color pixel to correct its chromaticity. . Specifically, the color filter layer 128 is formed by applying ink containing a color filter material and a solvent to a color filter including a plurality of openings formed in a matrix in units of pixels. The light sheet is formed on the upper substrate 130 with a cover glass.

[Panel Manufacturing Steps of Display Panel D] Next, the panel manufacturing steps of the display panel D will be described with a specific example. The light emitting layer 123 , the hole injection layer 120 and the hole transport layer 121 in the structure D of the display panel shown in FIGS. 10 to 12 can be formed by an inkjet method. Therefore, in this embodiment, the ink ejection amount measurement method or the ink ejection amount adjustment method described using FIG. 6 will be described as a method used for forming these three layers. Therefore, the panel manufacturing system of the display panel D according to the present embodiment is preferably a panel manufacturing system having the above-mentioned ink ejection amount measurement and adjustment device in addition to the display panel manufacturing device itself for manufacturing the display panel D. FIG. 13 is a flowchart showing the panel manufacturing steps of the display panel D. As shown in FIG.

In this embodiment, the inkjet head 23 corresponding to each layer is included. That is, the structure shown in FIG. 1 is prepared for forming the light emitting layer 123, the hole injection layer 120, and the hole transport layer 121, respectively. In addition, in order to simplify description, it assumes that the process for manufacturing the display panel D is collectively controlled by the control apparatus 50, and is demonstrated. At the beginning of the formal panel manufacturing process, the substrate 100 including the base material, the TFT layer, and the interlayer insulating layer is prepared.

(S1301) In S1301 , the control device 50 forms the pixel electrodes 119 on the substrate 100 . Specifically, a contact hole (not shown) is opened on the interlayer insulating layer of the substrate 100 to form the pixel electrode 119. It is patterned by shadow method and etching method. Furthermore, the pixel electrode 119 is in a state of being electrically connected to an electrode of a TFT constituting the substrate 100 .

(S1302) In S1302 , the control device 50 forms the banks 122 . In forming the banks 122 , the banks 122 are formed along a predetermined direction, and then the banks are formed in a direction perpendicular to the predetermined direction. The banks 122 are formed by laminating films of structural materials (for example, photosensitive resin materials) including the banks 122 . Then, the resin film is patterned to sequentially form banks. The patterning of the banks is performed by exposing the resin film with a photomask, and performing a developing step and a firing step (for example, at about 230° C. for about 60 minutes).

In the step of forming the banks 122 , first, a photosensitive resin film made of an organic photosensitive resin material such as acrylic resin, polyimide resin, novolac type phenolic resin, etc. is formed by spin coating or the like. After that, drying is performed to volatilize the solvent to a certain extent, and the photomask provided with predetermined openings is stacked. Furthermore, ultraviolet-ray irradiation is performed from this, the photoresist containing a photosensitive resin etc. is exposed, and the pattern which a photomask has is transferred to this photoresist. Next, an insulating layer formed by patterning the banks 122 by developing the photosensitive resin is formed. A so-called positive-type photoresist is generally used. The positive type is where the exposed parts are removed by development. The unexposed portion of the mask pattern is not developed, and the banks 122 remain with a certain thickness.

(S1303) In S1303 , the control device 50 stacks and forms a hole injection layer 120 on the pixel electrode 119 . The hole injection layer 120 can be formed by using an ink that dissolves a conductive polymer material in an organic solvent by an inkjet method. In this embodiment, when the hole injection layer 120 is formed, first, the ejection amount of each nozzle of the inkjet head 23 is adjusted by the method shown in FIG. 6 using the ink ejection amount measuring and adjusting device. In this case, the substrate B1 inserted in the insertion step ( S601 ) in FIG. 6 may be a substrate coated with a liquid-repellent coating material that is liquid-repellent to the ink used for forming the hole injection layer 120 . Then, after the adjustment of the ejection amount is completed, the hole injection layer 120 is formed at a predetermined position defined by the bank 122 with respect to ink containing a conductive polymer material using an inkjet method.

(S1304) In S1304 , the control device 50 forms a hole transport layer 121 on the hole injection layer 120 . The hole transport layer 121 can be formed by an inkjet method using an ink in which a conductive polymer material is dissolved in an organic solvent. In this embodiment, when the hole transport layer 121 is formed, first, the ejection amount of each nozzle of the inkjet head 23 is adjusted by the method shown in FIG. 6 using the ink ejection amount measuring and adjusting device. At this time, as the substrate B1 inserted in S601 of FIG. 6 , a substrate coated with a liquid-repellent coating material having liquid-repellency to the ink used for forming the hole transport layer 121 can be used. Then, after the adjustment of the ejection amount is completed, the hole transport layer 121 is formed at a predetermined position defined by the bank 122 with respect to ink containing a conductive polymer material using an inkjet method.

(S1305) In S1305 , the control device 50 forms a light emitting layer 123 by laminating on the hole transport layer 121 at a predetermined position defined by the bank 122 . In this embodiment, when forming the light-emitting layer 123, first, the ejection amount of each nozzle of the inkjet head 23 is adjusted by the method shown in FIG. 6 using the above-mentioned ink ejection amount measuring device. In this case, the substrate B1 inserted in the insertion step ( S601 ) in FIG. 6 may be a substrate coated with a liquid-repellent coating material having liquid-repellency to the ink used for forming the light emitting layer 123 . Then, after the adjustment of the ejection amount is completed, the light emitting layer 123 is formed using an inkjet method. As described above, the light emitting layers 123 are respectively formed corresponding to a plurality of colors reproduced by the organic EL light emitting panel (for example, three colors of R, G, and B). The arrangement of the light emitting layer 123 corresponding to each color on the substrate 100 is predetermined, and formed according to the arrangement. In addition, the formation order and arrangement of the light emitting layers 123 corresponding to the respective colors are not particularly limited, and arbitrary settings can be used.

(S1306) In S1306 , the control device 50 stacks and forms the electron transport layer 124 on the light emitting layer 123 . The electron transport layer 124 can be formed using a vacuum evaporation method or the like. In the case of wet film formation of the electron transport layer 124, similarly to the respective steps of S1303 to S1305, it is preferable to perform ink ejection by the method shown in FIG. Step of adjusting the injection amount of each nozzle of the head 23 ( S606 ).

(S1307) In S1307, the control device 50 laminates and forms the counter electrode 125 so as to cover the electron transport layer 124 as a whole film, which can be formed using a CVD method, a sputtering method, or the like.

(S1308) In S1308, the control device 50 laminates and forms the sealing layer 126 so as to cover the counter electrode 125 which is an integral film. The sealing layer 126 can be formed using a CVD method, a sputtering method, or the like, similarly to the counter electrode 125 .

(S1309) In S1309 , the control device 50 forms the color filter substrate 131 . In forming the color filter substrate 131 , first, a transparent upper substrate 130 is prepared. Next, on the surface of the upper substrate 130, the material of the color filter layer 128 (for example, G) mainly composed of an ultraviolet curable resin component is dispersed in a solvent, the paste is applied and the solvent is removed by a certain amount, and a predetermined pattern mask, and UV exposure. After that, it is cured, and the pattern mask and unhardened paste are removed for development to form a color filter layer (G). The color filter layer (R) and the color filter layer (B) are formed by repeating this procedure similarly to the color filter material of each color. Also, commercially available color filter products can be used instead of the paste. In addition, the color filter substrate 131 may be pre-formed, and only the formed color filter substrate 131 is disposed in this step.

(S1310) In S1310, the control device 50 performs lamination of the color filter substrate 131 and the back panel. In this step, first, the bonding layer 127 material mainly composed of ultraviolet curable resin such as acrylic resin, silicone resin, and epoxy resin is coated on the back panel including each layer from the substrate 100 to the sealing layer 126 . Next, the applied material is irradiated with ultraviolet rays, and both substrates are bonded together in a state where the relative positional relationship between the back panel and the color filter substrate 131 is aligned. At this time, bonding is performed so that gas does not enter between the two. Afterwards, the sealing step is completed by calcining the two substrates, so that the display panel D is completed. Then, the main panel manufacturing step ends.

Furthermore, in the above example, the inkjet method is used when forming the three layers of the luminescent layer 123, the hole injection layer 120, and the hole transport layer 121. At this time, the ink ejection amount measurement and adjustment device is used to The method shown in FIG. 6 performs the measurement and adjustment of the ejection amount of the ink in this embodiment. However, it is not limited to these layers, and a structure in which it is applied to at least one of the layers constituting the display panel D may be employed. Therefore, when the inkjet method can be used to form other layers, the method of measuring and adjusting the ejection amount of ink according to this embodiment can be applied to the formation of these layers.

[Verification example] Hereinafter, verification results using the method of this embodiment will be described. In this embodiment, five examples, namely, three compositions 1 to 3 having the characteristics of this embodiment, and two comparative compositions 1 and 2 as comparative examples are used for verification, and the results are shown. Comparing results. Here, the ink used when forming the hole injection layer 120 is taken as an example, and the same functional material is used in any ink for description. Fig. 14A is a tabular diagram summarizing the structures of the respective compositions.

(composition 1) In composition 1 of the ink, as a charge transporting material as a functional material, a functional polymer compound having a repeating structure of the following chemical formula P1 and 4 as an electron accepting compound were mixed in a ratio of 5:1. -Isopropyl-4'-methyldiphenyliodonium tetrakis(pentafluorophenyl)borate. In addition, Composition 1 used an organic solvent mixed at a ratio of butyl benzoate (boiling point: 250° C.):toluene (boiling point: 110° C.)=2:8 as the organic solvent. Then, these functional materials (solutes) were dissolved in an organic solvent, and the organic solvent (here, butyl benzoate) having a boiling point of 250° C. or higher was prepared in an amount of 2.0% by weight based on the entire composition 1 .

(composition 2) In ink composition 2, a functional polymer compound having a repeating structure of the chemical formula P1, and 4-iso Propyl-4'-methyldiphenyliodonium tetrakis(pentafluorophenyl)borate. In addition, Composition 2 used an organic solvent mixed at a ratio of 2-ethylhexyl benzoate (boiling point: 297° C.): mesitylene (boiling point: 164.7° C.) = 2:8. Then, these functional materials (solute) were dissolved in an organic solvent so that the organic solvent having a boiling point of 250° C. or higher (here, 2-ethylhexyl benzoate) was 2.0% by weight relative to the entire composition 2 Prepare.

(composition 3) In composition 3 of the ink, a functional polymer compound having a repeating structure of the chemical formula P1 and 4 as an electron-accepting compound were mixed in a ratio of 5:1 for the charge-transporting material as a functional material. -Isopropyl-4'-methyldiphenyliodonium tetrakis(pentafluorophenyl)borate. In addition, Composition 3 used an organic solvent mixed at a ratio of benzyl benzoate (boiling point: 323° C.):toluene (boiling point: 110° C.)=2:8 as the organic solvent. Then, these functional materials (solutes) were dissolved in an organic solvent, and the organic solvent (here, benzyl benzoate) having a boiling point of 250° C. or higher was prepared in such a manner that it contained 2.0% by weight of the entire composition 3 .

(composition 4) In composition 4 of the ink, a functional polymer compound having a repeating structure of the chemical formula P1 and 4 as an electron-accepting compound were mixed in a ratio of 5:1 for the charge-transporting material as a functional material. -Isopropyl-4'-methyldiphenyliodonium tetrakis(pentafluorophenyl)borate. In addition, Composition 4 used an organic solvent mixed at a ratio of benzyl benzoate (boiling point: 323° C.):cyclohexylbenzene (boiling point: 238.9° C.)=2:8 as the organic solvent. Then, these functional materials (solutes) were dissolved in an organic solvent, and the organic solvent (here, benzyl benzoate) having a boiling point of 250° C. or higher was prepared in an amount of 2.0% by weight based on the entire composition 4 .

(compared to composition 1) In ink comparative composition 1, as a functional material, a functional polymer compound having a repeating structure of the chemical formula P1 and an electron-accepting compound were mixed at a ratio of 5:1 for a charge-transporting material. 4-isopropyl-4'-methyldiphenyliodonium tetrakis (pentafluorophenyl) borate. In addition, comparative composition 1 used an organic solvent mixed at a ratio of tetralin (boiling point: 207.5° C.):toluene (boiling point: 110° C.)=2:8 as the organic solvent. Then, these functional materials (solutes) were dissolved in an organic solvent, and prepared so that the organic solvent on the high boiling point side (here, tetralin) was 2.0% by weight relative to the entire comparative composition 1 .

(compared to composition 2) In Comparative Composition 2 of the ink, a functional polymer compound having a repeating structure of the chemical formula P1 and an electron-accepting compound were mixed in a ratio of 5:1 for a charge-transporting material as a functional material. 4-isopropyl-4'-methyldiphenyliodonium tetrakis (pentafluorophenyl) borate. In addition, comparative composition 2 used, as an organic solvent, an organic solvent mixed at a ratio of cyclohexylbenzene (boiling point: 238.9° C.):toluene (boiling point: 110° C.)=2:8. Then, these functional materials (solutes) were dissolved in an organic solvent, and prepared so that the organic solvent on the high boiling point side (here, cyclohexylbenzene) was 2.0% by weight relative to the entire comparative composition 2 .

(Evaluation 1) First, as Evaluation 1 in this verification, changes in the diameter and volume of ink droplets were observed. The substrate B1 used in the measurement is a substrate in which a general polyimide-based photoresist was uniformly coated on the entire surface of a glass substrate as a liquid-repellent coating material. In addition, the surface of the polyimide cured film on the substrate was prepared, and a surface treatment was carried out so that the contact angle with anisole was 50 degrees using CF4 gas by the CVD method.

In Evaluation 1, measurement was performed according to the following procedure. Ink droplets of each composition were jetted onto the substrate B1. Afterwards, the ink droplet K was photographed at the time of natural drying (10 minutes) and natural drying (30 minutes), respectively. Then, the diameter of the ink droplet K is derived from the captured image, and the remaining volume of the ink droplet K is derived from the diameter. The values obtained as a result of this measurement are shown in Fig. 14B.

FIG. 14B shows the volume of the remaining ink droplet derived from the diameter of the ink droplet K derived from the image of each composition and its rate of change. From the results shown in FIG. 14B , inks (compositions 1 to 3) having 20% by weight or more of an organic solvent with a boiling point of 250°C or higher relative to the entire ink have a small volume change rate after a predetermined time (here, 10 minutes) has elapsed. , the liquid volume is stable. On the other hand, the ink (comparative composition 1) used as a comparative example was cured by natural drying for 10 minutes.

From the above measurement results, it can be seen that stable liquid amount measurement can be performed by using the ink having the characteristics of this embodiment and measuring the liquid amount after a predetermined time elapses.

(Evaluation 2) Next, evaluation 2 in this verification will be described. After receiving the result of Evaluation 1, the ejection amount of the inkjet head 23 was adjusted, the ink was applied to a predetermined coating area, and the film thickness of the dry coating film of the functional layer was measured after drying under reduced pressure. Substrate B2 used here was prepared as follows: using the polyimide photoresist used in Evaluation 1 on a glass substrate, the film thickness was 2 μm, the pixel width was 90 μm, and the bank width was 10 μm. After patterning in the order of μm, the liquid repellency of the bank surface was adjusted with anisole and the contact angle was 50 degrees by the CVD method.

FIG. 15 is a schematic diagram showing the position where the film thickness was measured on the substrate B2 in Evaluation 2. FIG. In the test of evaluation 2, as shown by the arrow in FIG. 15 , at the center position in the X direction of the ink coating area (corresponding to the self-luminous area 100a in FIG. 11 ) of the substrate B2, the self-luminescence was measured along the Y-axis. Film thickness tip to tip. The measured length here from tip to tip is set at 20 cm. Furthermore, the target value of the film thickness after drying of the functional layer was set to 60 nm.

Fig. 16 shows the measurement results of Evaluation 2 in this verification. In addition, regarding Comparative Composition 1, as shown in FIG. 14B , since the droplet diameter could not be measured in Evaluation 1, the ejection amount could not be adjusted, and Evaluation 2 was not performed. In FIG. 16 , the vertical axis represents the film thickness [nm] of the formed layer, and the horizontal axis represents the position [cm] of the formed layer. As described above, the measurement position of the film thickness was set to a range of 20 cm from the end to the end.

Referring to FIG. 16 , for Compositions 1 to 3 having the characteristics of the ink of this embodiment, the variation in the film thickness of the formed functional layer is also small, and is at a level suitable for manufacturing a display panel D. On the other hand, in Comparative Composition 2, it was confirmed that the adjustment of the injection amount could not be smoothly performed, and the film thickness variation at the coating end due to drying and the fluidity were insufficient, so that a uniform film thickness could not be formed.

(Evaluation 3) Next, the following evaluations were performed. As the base material B1 used in the measurement, a substrate having a liquid-repellent resist coated on a glass substrate to form a liquid-repellent film was used. The contact angle of the ink of composition 4 on the substrate B1 was 61.5 degrees. The ink droplets of composition 4 were sprayed onto the substrate B1, and the ink droplets K were sprayed at 1 minute, 5 minutes, 10 minutes, 20 minutes, and 30 minutes in a naturally dry state. shooting. Then, the diameter of the ink droplet K is derived from the captured image. Furthermore, after drying by heating and evaporating the organic solvent, imaging is performed in the same manner, and the diameter of the droplet K is derived. The values obtained as a result of this measurement are shown in FIG. 17 .

In this evaluation, based on the change in the diameter of the droplet K, it is judged whether or not a predetermined amount of ink is maintained relative to the ejection amount of the ink after a predetermined time elapses after the ink is ejected onto the substrate B1. FIG. 17 shows the change in the diameter of the ink droplet K derived from the image of the composition 4 . From the results shown in FIG. 17, it can be seen that 20% by weight or more of an organic solvent having a boiling point of 250° C. or higher with respect to the entire ink, even if a solvent having a boiling point of 238.9° C. or lower as an organic solvent having a boiling point of less than 250° C. After 5 minutes, the change rate of the droplet diameter is also small, and then until 30 minutes after natural drying, the change rate of the droplet diameter is small and stable. After natural drying for 30 minutes, the droplet K became smaller after heating and drying to remove the organic solvent. Therefore, it can be seen that organic solvents with a boiling point of 250° C. or higher are stably present during natural drying for 30 minutes.

As mentioned above, organic solvents with a boiling point of 250° C. or higher are not evaporated to dryness in a room temperature environment, so there is almost no change in the amount, and the droplet diameter can be measured without a special device. In addition, by containing an organic solvent having a boiling point of 250° C. or higher, fluidity of ink can be ensured in an organic EL display panel having row-shaped banks, and variations in film thickness can be suppressed.

By using the ink of the present invention, it is not necessary to measure the ink droplet that changes with time each time, and the ejection amount of the ink droplet can be derived in a short time. Then, based on the derived ejection amount, the droplet ejection amount of each inkjet head nozzle can be easily made uniform. Therefore, reduction in production efficiency of the inkjet device caused by measurement of the ejection amount of liquid droplets can be suppressed. In addition, in the present embodiment, large-scale facilities are not required for liquid droplet observation, and thus the device cost is also reduced.

In addition, by performing ejection failure inspection using the measurement method of this embodiment, it is possible to detect nozzle ejection failures such as nozzle detachment and flight deflection of liquid droplets.

In addition, in the present invention, the amount of ink required to measure the liquid volume of ink droplets ejected from the inkjet head is only required to be a very small amount, so it is possible to efficiently perform the measurement without wasting functional materials such as expensive organic EL materials. Take advantage of it. In addition, the ink of the present invention can also reduce coating unevenness caused by natural drying and the like when forming a pixel pattern on a substrate after adjusting the ejection amount.

＜Other Embodiments＞ In addition, in the present invention, it can also be realized by supplying a program or application for realizing the functions of the above-mentioned one or more embodiments to a system or device using a network or a storage medium, and the system or device One or more processors in the device's computer read and execute the program.

In addition, it may also be implemented by a circuit (for example, an application specific integrated circuit (ASIC) or a field programmable gate array (Field Programmable Gate Array, FPGA)) that realizes more than one function.

In this way, the present invention is not limited to the above-described embodiments, and the intended content of the present invention is to combine the various structures of the embodiments, or to make changes and applications by those skilled in the art based on the description in the specification and well-known technologies, including in within the scope of protection.

As above, various embodiments have been described with reference to the drawings, but the present invention is of course not limited to the examples described above. It is clear for those skilled in the art that various modifications or amendments can be conceived within the scope described in the claims, and it is understood that these naturally also belong to the technical scope of the present invention. In addition, the constituent elements of the above-described embodiments may be combined arbitrarily within a range not departing from the gist of the invention.

In addition, this application is based on the Japanese patent application (Japanese Patent Application No. 2020-202834) filed on December 7, 2020, the content of which is incorporated in this application as a reference. [Industrial availability]

The method for measuring the ejection amount of the ink of the present invention, the manufacturing device of the organic EL display panel, the ink, and the organic EL display panel manufactured using the ink can be widely used in devices such as televisions, personal computers, mobile phones, and various devices with display panels. Manufacture of display panels, etc. in electronic equipment. In addition, it can be widely used in the manufacture of electronic devices and the like including a step of forming a functional layer using an ink coating step.

1: inkjet device 10: X-axis table 10a: Zoning area 10b: Non-zoning areas 10c: part of the area 10e: Display pixel arrangement area 10ne: non-luminous area 11: Y-axis table 12: X-axis guide rail 13: Y-axis guide rail 20: carriage unit 21: Carriage support part 22: Carriage 23: inkjet head 30: Camera unit 31: camera 32: Camera support part 40: stage 41: Stage rotation mechanism 42: X-axis slider 50: Control device 100: Substrate 100a: self-luminous area 100aB, 100aG, 100aR: self-luminous area 100b: Non-self-illuminating area 100e: unit element 119: pixel electrode 119b: Contact area 119c: Contact hole 120: hole injection layer 121: Hole transport layer 122: Dike 122X: column embankment 122Y: Embankment Department 123: luminescent layer 124: electron transport layer 125: counter electrode 126: sealing layer 127: Bonding layer 128:Color filter layer 130: upper substrate 131: Color filter substrate 201: nozzle hole 202: Ink droplet 300: sealing member B: Substrate B1: Substrate (for measurement of ejection amount) B2: Substrate (for pattern formation) D: display panel K: ink droplet S601～S607, S1301～S1310: steps

FIG. 1 is a schematic diagram showing a configuration example of an inkjet device according to an embodiment of the present invention. FIG. 2 is a schematic diagram showing a configuration example of an inkjet device according to an embodiment of the present invention. FIG. 3 is a diagram for explaining ejection by the inkjet head according to the embodiment of the present invention. Fig. 4 is a graph for explaining the characteristics of the ink according to the embodiment of the present invention. FIG. 5 is a tabular diagram illustrating the characteristics of ink according to one embodiment of the present invention. FIG. 6 is a flowchart of a method for measuring and adjusting ink ejection volume according to an embodiment of the present invention. FIG. 7 is a diagram for explaining an ink ejection step according to an embodiment of the present invention. Fig. 8 is a diagram for explaining an ink droplet acquisition step according to an embodiment of the present invention. FIG. 9A is a diagram for explaining an ink ejection state according to an embodiment of the present invention. FIG. 9B is a diagram for explaining the ejection state of the ink according to the embodiment of the present invention. 10 is a plan view of a structural example of a display panel according to an embodiment of the present invention. 11 is a plan view of a structural example of a display panel according to an embodiment of the present invention. 12 is a cross-sectional view of a structural example of a display panel according to an embodiment of the present invention. FIG. 13 is a flow chart of manufacturing steps of a display panel according to an embodiment of the present invention. Figure 14A is a table illustrating experimental results for the method of one embodiment of the present invention. Figure 14B is a table illustrating experimental results for the method of one embodiment of the present invention. Fig. 15 is a diagram for explaining a test of one embodiment of the present invention. Fig. 16 is a graph illustrating test results of a method according to an embodiment of the present invention. Fig. 17 is a table for explaining test results of a method according to an embodiment of the present invention.

S601~S607: steps

Claims (22)

A measurement adjustment method at least including a measurement method for measuring the ejection amount of ink from an inkjet head, the measurement adjustment method is characterized in that, The measurement methods include: an ejecting step, ejecting ink from the inkjet head onto the substrate; an acquiring step of acquiring an image of ink jetted onto said substrate; and an deriving step of deriving an ejection amount of ink from the inkjet head based on information obtained from the image, The ink ejected onto the base material maintains an amount proportional to the amount of ink ejected from the ink jet head after a predetermined time elapses after ejection from the ink jet head. The measurement adjustment method according to claim 1, further comprising a drying step, the drying step is to dry the ink sprayed onto the substrate within the specified time, and the obtaining step is to dry the ink in the drying step Execute afterwards. The measurement adjustment method as described in claim 1 or 2, wherein the ink comprises a solvent and a functional material, The solvent includes an organic solvent having a boiling point of 250° C. or higher. A measurement adjustment method at least including a measurement method for measuring the ejection amount of ink from an inkjet head, the measurement adjustment method is characterized in that, The measurement methods include: an ejecting step, ejecting ink from the inkjet head onto the substrate; an acquiring step of acquiring an image of ink jetted onto said substrate; and an deriving step of deriving an ejection amount of ink from the inkjet head based on information obtained from the image, The ink contains a solvent and a functional material, The solvent includes an organic solvent having a boiling point of 250° C. or higher. The measurement adjustment method as described in Claim 4, further comprising a drying step, the drying step is to dry the ink sprayed onto the substrate within a specified time, and the obtaining step is performed after the drying step . The measurement adjustment method according to any one of claims 1-3 and claim 5, wherein the prescribed time is more than 5 minutes. The measurement adjustment method as described in any one of claim items 1 to 6, wherein the ink comprises a solvent and a functional material, The solvent includes an organic solvent having a boiling point of 300° C. or higher. The measurement adjustment method according to any one of claims 3 to 5 and claim 7, wherein the ink contains 20% by weight or more of the organic solvent. The measurement adjustment method according to any one of claims 1 to 8, wherein the substrate is coated with a liquid-repellent coating material having liquid-repellency to the ink. The measurement adjustment method as described in any one of claim items 1 to 9, wherein the deriving step includes taking the diameter of the droplet of ink from said image, deriving a volume of ink on said substrate using at least said obtained diameter, An ejection amount of ink from the inkjet head is derived based on the derived volume of ink on the substrate. The measurement adjustment method according to any one of claims 1 to 10, further comprising an adjustment step of adjusting the ejection amount from the inkjet head based on the ejection amount of the ink derived in the deriving step. The measurement adjustment method according to claim 11, wherein the measurement adjustment method is when forming at least any one of the light-emitting layer, the hole injection layer, and the hole transport layer among the functional layers constituting the organic electroluminescent display panel use. A device for measuring and adjusting the amount of ink ejection, which is aimed at an inkjet head, and uses the measurement and adjustment method described in any one of Claims 1-12. A panel manufacturing system for an organic electroluminescent display panel, comprising the ink ejection amount measurement and adjustment device as described in claim 13. A method for manufacturing an organic electroluminescence display panel, which uses the measurement and adjustment method described in any one of Claims 1-12. A method for manufacturing an organic electroluminescent display panel, which uses the panel manufacturing system described in claim 14. A kind of ink, is used for as the measuring adjustment method described in any one in claim item 1～12, and described ink is characterized in that, Contains: solvent, and functional materials corresponding to the functional layer, The solvent includes an organic solvent having a boiling point of 250° C. or higher. An ink used in the ink ejection amount measurement and adjustment device according to claim 13, wherein the ink is characterized in that, Contains: solvent, and functional materials corresponding to the functional layer, The solvent includes an organic solvent having a boiling point of 250° C. or higher. An ink used in the panel manufacturing system of the organic electroluminescent display panel as claimed in claim 14, the ink is characterized in that, Contains: solvent, and functional materials corresponding to the functional layer, The solvent includes an organic solvent having a boiling point of 250° C. or higher. The ink according to any one of claims 17 to 19, wherein the ink contains 20% by weight or more of the organic solvent. The ink according to any one of Claims 17 to 20, wherein after the ink is dried for a predetermined time, it maintains a constant volume relative to the volume before the drying. An organic electroluminescent display panel, using the ink described in any one of claims 17-21 to form a functional layer.

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