KR20230117124A - Method for measuring and adjusting ink ejection amount, ink ejection amount measuring and adjusting device, panel manufacturing system for organic EL display panel, method for manufacturing organic EL display panel, ink, and organic EL display panel manufactured using ink - Google Patents

Abstract

A measurement adjustment method including a measurement method for measuring at least an amount of ink ejected from an ink ejection head, wherein the measurement method ejects ink from the ink ejection head onto a substrate, and displays an image of the ink ejected on the substrate. and, based on information obtained from the image, an ejection amount of ink from the ink ejection head is derived, and the ink ejected onto the substrate is, after a predetermined time elapses after being ejected from the ink ejection head, A constant ratio of the amount of ink ejected from the ink ejection head is maintained.

Description

Method for measuring and adjusting ink ejection amount, ink ejection amount measuring and adjusting device, 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 an ink ejection amount by an ink ejection head, an ink ejection amount measurement and adjusting device, a panel manufacturing system for an organic EL display panel, a method for manufacturing an organic EL display panel, an ink, and an organic material manufactured using the ink. It relates to an EL display panel.

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

In recent years, inkjet devices have been used for the manufacture of large-screen color filters and organic EL display panels. One of the manufacturing processes of an organic EL display panel is a film formation process of an organic EL film, and inkjet printing technology is used in this process. It is known that when a color filter or an organic EL display panel is manufactured, variations in the discharge amount of ink discharged (placed) on a substrate result in variation in the thickness of the formed film, causing uneven light emission in the organic EL display panel. Therefore, in order to manufacture the organic EL display panel with good precision, it is necessary to control the discharge amount of ink for each nozzle.

In Patent Literature 1, liquid droplets are discharged on a weighing balance, the discharge weight of each ink discharge head is measured, and based on the measurement result, control is performed so that the discharge weight of each ink discharge head is uniform. In Patent Literature 2, the discharge weight is adjusted by measuring the film thickness of the discharged droplet and changing the discharge pattern based on the measured film thickness. In Patent Document 3, light is irradiated from a ring-shaped illuminator to droplets with the optical axis of the observation optical system and the center of the ring-shaped illuminator aligned, and a virtual image of the ring-shaped illuminator generated from the droplets by the irradiation of light is captured by the observation optical system. The height of the droplet is measured based on the image. Patent Literature 4 discloses a technique of measuring the impact diameter of a droplet of each nozzle based on image data of a droplet by evaporation of a solvent. Further, in Patent Literature 4, a cover that prevents evaporation is used in order to prevent the volume from changing due to evaporation of droplets from impact to measurement.

Japanese Unexamined Patent Publication No. 2004-209429 Japanese Unexamined Patent Publication No. 2006-341231 Japanese Unexamined Patent Publication No. 2010-169413 Japanese Unexamined Patent Publication No. 2019-169413

On the other hand, in the measuring method of Patent Literature 1, while a large amount of ink is required, since the measurement requires a great amount of time, the operating rate of the inkjet apparatus is significantly reduced. In the method of Patent Literature 2, there is a possibility that the ejection weight of each ink ejection head may not be uniform because there is no means for calculating the ejection weight of droplets ejected for each nozzle. In addition, it is difficult to say that only combining only the technique described in Patent Literature 3 with, for example, an inkjet device is sufficient to accurately measure droplets that become smaller as high definition progresses. In addition, since the amount of droplets of minute liquid droplets such as organic EL materials tends to change due to evaporation of the solvent, a technique for accurately determining the volume of the droplets in consideration of such volume changes is required. The droplet amount measurement method described in Patent Literature 4 uses a cover and its disposition mechanism to prevent evaporation. Such a mechanism constitutes a large-scale structure as an entire device.

The present invention has been made in order to solve the above problems, and an object of the present invention is to accurately measure the discharge amount of droplets without requiring an evaporation prevention mechanism in response to the problem that the amount of droplets easily changes due to evaporation of the solvent. .

In order to solve the said subject, this invention has the following structures. That is, as a measurement adjustment method including at least a measurement method of measuring the amount of ink ejected from the ink ejection head,

The measurement method,

a discharge step of discharging ink from the ink discharge head onto a substrate;

an acquisition step of acquiring an image of the ink ejected on the substrate;

a derivation step of deriving an ejection amount of ink from the ink ejection head based on information obtained from the image;

The ink ejected onto the substrate maintains an amount at a constant ratio to the amount of ink ejected from the ink ejection head after a predetermined time elapses after being ejected from the ink ejection head.

Further, in one aspect of the present invention, the measurement adjustment method further includes a drying step of drying the ink ejected on the substrate for the predetermined time period;

After the drying process, the acquisition process is executed.

Further, in one aspect of the present invention, the ink contains a solvent and a functional material,

The solvent contains an organic solvent having a boiling point of 250°C or higher.

Moreover, another aspect of this invention has the following structures. That is, as a measurement adjustment method including at least a measurement method of measuring the amount of ink ejected from the ink ejection head,

The measurement method,

a discharge step of discharging ink from the ink discharge head onto a substrate;

an acquisition step of acquiring an image of the ink ejected on the substrate;

a derivation step of deriving an ejection amount of ink from the ink ejection head based on information obtained from the image;

The ink includes a solvent and a functional material,

The solvent contains an organic solvent having a boiling point of 250°C or higher.

Further, in one aspect of the present invention, the measurement adjustment method further includes a drying step of drying the ink ejected on the substrate for a predetermined period of time;

After the drying process, the acquisition process is executed.

Moreover, in one aspect of the present invention, the predetermined time is 5 minutes or longer.

Further, in one aspect of the present invention, the ink contains a solvent and a functional material,

The said solvent contains an organic solvent with a boiling point of 300 degreeC or more.

Moreover, in one embodiment of the present invention, the organic solvent is contained at 20% by weight or more with respect to the ink.

Furthermore, in one aspect of the present invention, the substrate is coated with a liquid-repellent coating material having liquid-repellency to the ink.

Moreover, in one aspect of the present invention, the derivation step,

extracting the diameter of the ink droplet from the image;

derive the volume of ink on the substrate using at least the extracted diameter;

The amount of ink ejected from the ink ejection head is derived from the derived volume of ink on the substrate.

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

In one embodiment of the present invention, the measurement adjustment method is used when forming at least one of a light emitting layer, a hole injection layer, and a 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, as the ink ejection amount measuring and adjusting device, the above measurement and adjusting method is used.

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

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

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

Moreover, another aspect of this invention has the following structures. That is, as the ink used in the measurement adjustment method,

A solvent and a functional material corresponding to the functional layer,

The solvent contains an organic solvent having a boiling point of 250°C or higher.

Moreover, another aspect of this invention has the following structures. That is, as the ink used in the ink ejection amount measuring and adjusting device,

A solvent and a functional material corresponding to the functional layer,

The solvent contains an organic solvent having a boiling point of 250°C or higher.

Moreover, another aspect of this invention has the following structures. That is, as an ink used in the panel manufacturing system of the organic EL display panel,

A solvent and a functional material corresponding to the functional layer,

The solvent contains an organic solvent having a boiling point of 250°C or higher.

Moreover, in one embodiment of the present invention, the organic solvent is contained at 20% by weight or more with respect to the ink.

Further, in one embodiment of the present invention, after drying for a predetermined time, the amount of the ink is maintained at a constant ratio with respect to the volume before the drying.

Moreover, another aspect of this invention has the following structures. That is, as an organic EL display panel, a functional layer is formed using the ink.

According to the present invention, the droplet discharge amount can be accurately measured and/or adjusted with a simple configuration.

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 an ink ejection head according to an embodiment of the present invention.
Fig. 4 is a graph for explaining the characteristics of an ink according to an embodiment of the present invention.
Fig. 5 is a table diagram for explaining the characteristics of an ink according to an embodiment of the present invention.
6 is a flow chart of an ink ejection amount measurement and adjustment step 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.
9A is a diagram for explaining an ink ejection state according to an embodiment of the present invention.
9B is a diagram for explaining an ink ejection state according to an embodiment of the present invention.
10 is a plan view showing a configuration example of a display panel according to an embodiment of the present invention.
11 is a plan view showing a configuration example of a display panel according to an embodiment of the present invention.
12 is a cross-sectional view showing a configuration example of a display panel according to an embodiment of the present invention.
13 is a flowchart of a panel manufacturing process of a display panel according to an embodiment of the present invention.
14A is a table diagram for explaining test results by a method related to one embodiment of the present invention.
14B is a table diagram for explaining test results by a method related to one embodiment of the present invention.
15 is a diagram for explaining a test related to one embodiment of the present invention.
16 is a graph for explaining test results by a method related to one embodiment of the present invention.
17 is a table diagram for explaining test results by a method related to one embodiment of the present invention.

EMBODIMENT OF THE INVENTION Hereinafter, the form for implementing this invention is demonstrated with reference to drawings etc. In addition, the embodiment described below is one embodiment for explaining the present invention, and is not intended to be construed as limiting the present invention, and all the configurations described in each embodiment are the subject of the present invention. It cannot be said that it is a necessary configuration to solve the problem. Moreover, in each figure, the same reference number is attached|subjected to the same component, and a correspondence relationship is shown.

<First Embodiment>

[Device configuration]

An example of a configuration 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 the ink ejection amount measurement from the ink ejection head in the inkjet device according to the present embodiment, which can perform a step of measuring and adjusting the ink ejection amount from the ink ejection head, which will be described later. Indicates an adjustment device. 1 is a side view schematically showing an outline of the configuration of an inkjet device 1 according to the present embodiment. Fig. 2 is a plan view schematically showing an outline of the configuration of the inkjet device 1 according to the present embodiment. In the following, the main scanning direction of the stage 40 (that is, the transport direction of the substrate) is the X-axis direction, and the sub-scanning direction orthogonal to the main scanning direction is the Y-axis direction, and the X-axis direction and the Y-axis direction are orthogonal to the X-axis direction. The vertical direction to be used is the Z-axis direction. Further, the rotation direction around the Z-axis direction is the θ direction. In each drawing, it is assumed that each axial direction corresponds to each other.

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

(carriage unit)

The carriage unit 20 includes a carriage support 21 , a carriage 22 , and an ink ejection head 23 . On the lower surface of the carriage unit 20, one or a plurality of carriages 22 and one or a plurality of ink ejection heads 23 are provided corresponding to the type of ink to be ejected. In this embodiment, for example, a plurality of ink ejection heads 23 having a configuration of a line head system corresponding to the width of the substrate in the Y-axis direction are formed. A plurality of nozzles are formed on the lower surface of the ink ejection head 23, that is, on the ink ejection surface, and ink droplets are ejected from the nozzles. For example, when ejecting three types of ink corresponding to three colors of R (Red), G (Green), and B (Blue), three rows of ink ejection heads 23 are provided. In addition, the number of types of inks compatible with the inkjet device 1 is not particularly limited, and may increase or decrease depending on the configuration of the product. Also, a supply unit (not shown) for supplying ink is connected to the carriage unit 20, and ink is supplied at the right time.

The carriage support 21 is mounted on the Y-axis guide rail 13 and is configured to be freely movable in the Y-axis direction by a Y-axis linear motor (not shown) formed on the Y-axis guide rail 13 . For example, the carriage unit 20 is moved so as to be positioned on the X-axis table 10 when ejecting ink, as shown in FIG. 2, and when cleaning the ink ejection head 23, the Y-axis guide rail ( 13) may be moved to the retracted position and the cleaning operation is performed. As the cleaning operation, preliminary ejection of ink, wiping of the ejection surface of the ink ejection head 23, and the like are exemplified.

FIG. 3 is a diagram schematically showing a situation in which ink droplets 202 are ejected from the ink ejection head 23. As shown in FIG. The ink ejection head 23 according to this embodiment shows an example using a piezo system. In the piezo method, a driving voltage is applied to a piezoelectric element (not shown) inside the ink ejection head 23 to cause the piezoelectric element to expand and contract, and a predetermined amount of ink droplets 202 are ejected from a small hole called a nozzle hole 201. discharge The ejected ink droplet 202 lands on the substrate B disposed on the stage 40 . In addition, 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 takes a picture of the substrate B installed on the stage 40 and acquires an image including the substrate B and the ink droplets 202 ejected thereon. The camera unit 30 is configured to include a camera 31 as a photographing unit.

As shown in FIG. 1 , the camera 31 is formed on the Y-axis table 11 on one side among the pair of Y-axis tables 11 and is supported by the camera support part 32 . In the example of FIG. 1 , the camera 31 is installed downstream of the ink ejection head 23 in the transport direction (X-axis direction) of the substrate B. A moving mechanism (not shown) for moving the camera 31 is provided in the camera support 32, and the camera 31 is freely movable in the Y-axis direction. The camera 31 is formed corresponding to the carriage unit 20 (carriage 22), for example, and a plurality of cameras may be formed along the Y-axis direction. Accordingly, a plurality of cameras 31 may be provided in order to shorten the time of the photographing operation. The camera 31 according to the present embodiment has a function capable of capturing an image of a resolution capable of reproducible each of the ink droplets 202 ejected onto the substrate B. In addition, at the time of imaging by the camera 31, the structure which irradiates illumination light from an illuminator (not shown) onto the base material B may be sufficient. As a light source of the illuminator (not shown), a light emitting diode (LED) or the like can be used, for example.

(stage)

The stage 40 is, for example, a vacuum adsorption stage, and can adsorb and fix the substrate (B). In the present embodiment, the base material (B) corresponds to a base material for measuring the ejection amount of ink or a base material for forming a pixel pattern. For each substrate, in the case where an explanation is required individually, subscripts are shown as the substrate (B1) for measuring the ejection amount of ink and the substrate (B2) for forming the display panel, and in the case of a combined description, the description It is shown as (B). The base material (B1) is coated with a liquid-repellent coating material on the surface from which ink is ejected, and has ink-repellent properties. The composition of the liquid-repellent coating material here is defined according to the composition of the ink.

The stage 40 is supported so as to be able to freely rotate in the θ direction around the Z axis by a stage rotation mechanism 41 formed on the lower surface side of the stage 40 . The stage rotation mechanism 41 is supported by an X-axis slider 42 formed 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) formed on the X-axis guide rail 12 .

In addition, although details will be described later, a display panel that can be manufactured using the inkjet device 1 according to the present embodiment is composed of a plurality of layers. These layers include one or a plurality of layers that can be formed by an inkjet method. Therefore, in the case of forming each of these layers, a plurality of configurations shown in Fig. 1 or Fig. 2 can be formed and applied. Since the type of ink used in each layer is different, even if a mechanism required for measurement or formation such as the carriage unit 20 or a base material B1 for measuring the discharge amount of ink is formed corresponding to the function of each layer, do.

(controller)

The inkjet device 1 includes a control device 50 . The control device 50 may be realized as an information processing device including, for example, a control unit not shown, a storage unit, and an output unit. The control unit may be constituted by a central processing unit (CPU), a micro processing unit (MPU), a digital single processor (DSP), or a dedicated circuit. The storage unit is composed of volatile or non-volatile storage media such as HDD (Hard Disk Drive), ROM (Read Only Memory) or RAM (Random Access Memory), and can input/output various types of information according to instructions from the control unit. . Also, the storage unit stores a program for realizing processing related to the present embodiment. The output unit is composed of a speaker, a light, or a display device such as a liquid crystal display, and performs various outputs according to instructions from the control unit. The output method by the output device is not particularly limited, but may be, for example, visual output by screen output. Moreover, the output unit may be a network interface provided with a communication function, and may perform an output operation by data transmission to an external device (not shown) via a network (not shown).

The control device 50 comprehensively controls the position of the stage 40 and the carriage unit 20 and controls the ejection of ink by the ink ejection head 23, for example. In ink ejection, the control device 50 outputs the control signal to the ink ejection head 23 according to the image pattern to be formed. In addition, the control device 50 controls the photographing operation by the camera unit 30 in order to measure the ejection amount of ink. In addition, the control device 50 performs various controls for generating the display panel D. In this embodiment, an organic EL display panel will be described as an example of the display panel D.

[Characteristics of Ink]

Characteristics of the ink according to the present embodiment will be described. In addition, as the ink related to the present embodiment, an ink used when manufacturing an organic EL display panel will be described as an example, but as long as it is an ink used when manufacturing a product to which the inkjet device 1 described above can be applied, this It is not limiting. In the manufacture of organic EL display panels, it is required to adjust the discharge amount of ink with high precision. When performing such an adjustment, it is necessary to measure the ejection amount of ink for each nozzle, but it has been difficult to accurately measure the ejection amount due to the change in volume due to drying of the ink. In contrast, in the present embodiment, an ink having a composition characterized by a tendency to change in volume due to drying is used.

The ink is composed of a solute containing a functional material and a solvent containing an organic solvent. A functional material is for realizing the function of a layer formed by an inkjet method in a layer constituting an organic EL display panel. The organic solvent needs to 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 according to the present embodiment. Here, description is given using the ink (Example) related to the present embodiment and the ink for comparison (Comparative Example).

Compared with the conventional ink, the ink according to the present embodiment has a characteristic in that the volume due to drying is stable after a lapse of a certain period of time. Fig. 4 is a graph showing a change in the volume of a droplet with the lapse of time in the ink according to the present embodiment and a comparative example. In Fig. 4, the abscissa axis represents the time [min] that the ink droplet was left after ejection, and the ordinate axis represents the volume [pl] of the ink droplet. It is assumed that the volume of the ink droplet in the original example and the comparative example is the same.

In the example of Fig. 4, in the case of Comparative Example, the volume of the ink droplet decreased with the lapse of time, and became approximately zero when the standing time was 10 minutes. On the other hand, in the case of the embodiment, the volume of the ink droplet decreases with the passage of time, but after a certain amount of time has elapsed, the change in volume almost disappears and the volume is maintained almost constant. As indicated by the arrows in Fig. 4, in the examples, after the standing time has elapsed of 5 minutes, the decrease in volume is almost eliminated, and the volume is constant. FIG. 5 shows the value of the volume for each elapsed time (leaving time) corresponding to FIG. 4 . In both the Examples and Comparative Examples, the volume decreases in almost the same tendency until a certain amount of standing time has elapsed. After that (after 5 minutes have elapsed), a difference has occurred in the decreasing tendency. In short, the ink according to the present embodiment is assumed to have characteristics in which evaporation of the solvent almost disappears after a certain standing time (i.e., drying time) has elapsed, and the change in volume of the ink is suppressed and stabilized. The stabilization by suppressing the volume change of the ink refers to a state in which the volume change of the ink is almost eliminated due to almost no evaporation of the solvent from the ink, and a constant ratio is maintained. In the present embodiment, the state in which the amount at a constant ratio is maintained may be, for example, a state in which the volume reduction rate is 0.01 pl/min or less.

This assumes, for example, that the volume of the ink stabilized by suppressing the volume change is 1.00 pl. Here, in performing the acquisition step of acquiring the image of the ink ejected on the base material B after ejection of the ink from the ink ejection head 23, what is the cause of the time from the ejection step of the ink to the acquisition step? It is said that there is a difference in Even if this occurs with a variation of 1 minute, the volume change is 1% or less (*), and such a characteristic is a desirable characteristic in terms of production of an organic EL panel. From the viewpoint of increasing the accuracy of the amount of ink drawn out from the ink ejection head 23, it is more preferably 0.005 pl/min or less, and particularly preferably 0.001 pl/min or less ((※) 1.00 pl ink is 0.01 pl/min When the volume decreases at /min, the amount of volume decrease per minute is 0.01 pl, which is 1% of 1.00 pl).

In order to realize the above characteristics, the composition of the ink according to the present embodiment is determined. As described above, the ink is constituted by including a solvent and a solute. Examples of organic solvents usable in the present embodiment include aliphatic hydrocarbon compounds, aliphatic alcohol compounds, aliphatic ether compounds, aliphatic glycol compounds, aliphatic ester compounds, aliphatic aldehyde compounds, aliphatic ketone compounds, aliphatic carboxyl based compounds, aliphatic compounds containing a nitrogen atom, aliphatic compounds containing a sulfur atom, alicyclic compounds, alicyclic compounds having a heteroatom, aromatic hydrocarbon compounds, aromatic alcohol compounds, aromatic ester compounds, aromatic ether compounds, aromatic aldehyde-based compounds, aromatic carboxylic compounds, and the like.

Specifically, examples of the aliphatic hydrocarbon compound include n-octane, nonane, n-decane, n-undecane, and the like. Examples of the aliphatic alcohol compounds include 1-butanol, 1-pentanol, 2-pentanol, 1-hexanol, 2-hexanol, 1-heptanol, 2-heptanol, 1-octanol, and 2-octanol. , 2-nonanol, n-dodecane, n-tridecane, n-tetradecane, 1-nonanol, n-decanol, 2-decanol, n-undecanol, isodecanol and the like.

Dibutyl ether (boiling point 137-143 degreeC) etc. are mentioned as an aliphatic ether type compound.

As the aliphatic glycol-based compound, ethylene glycol, ethylene glycol monoethyl ether, ethylene glycol diethyl ether, ethylene glycol monomethyl ether, propylene glycol, propylene glycol monoethyl ether, propylene glycol monomethyl ether, hexylene glycol, diethylene 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. are mentioned.

As the aliphatic ester compound, n-butyl formate, allyl acetate, n-butyl acetate, dimethyl succinate, diethyl oxalate, dimethyl oxalate, methyl lactate, ethyl lactate, methyl pyruvate, ethyl pyruvate, dimethyl malonate, diethyl malonate, etc. can be heard

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

Examples of the aliphatic aldehyde-based compound include furfural and the like.

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

As an aliphatic carboxylic compound, formic acid, acetic acid, propionic acid, etc. are mentioned.

Examples of the aliphatic compound containing a nitrogen atom include N,N-dimethylacetamide, N,N-dimethylformamide, N,N-diisopropylethylamine, and acetamide.

As an aliphatic compound containing a sulfur atom, dimethyl sulfoxide etc. are mentioned.

Examples of the alicyclic hydrocarbon compound include methylcyclohexane, dimethylcyclohexane, ethylcyclohexane, cycloheptane, decalin, cyclopentanol, cyclohexanol, methylcyclohexanol, dimethylcyclohexanol, cyclohexenol, cyclohexylmethanol, tetrahydrofurfuryl alcohol, furfuryl alcohol, cyclopentanone, cyclohexanone, dioxane, methylcyclohexanone, bicyclohexyl and the like.

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

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

Propylene carbonate is mentioned as an aliphatic carbonate compound.

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

Sulfolane etc. are mentioned as an alicyclic compound containing a sulfur atom.

Examples of the aromatic hydrocarbon compound include toluene, o-xylene, p-xylene, m-xylene, mesitylene, 1,2,4-trimethylbenzene, ethylbenzene, o-diethylbenzene, m-diethylbenzene, p-diethylbenzene, o-ethylmethylbenzene, p-ethylmethylbenzene, m-ethylmethylbenzene, n-propylbenzene, isopropylbenzene, n-butylbenzene, s-butylbenzene, isobutylbenzene, t-butyl benzene, n-pentylbenzene, n-hexylbenzene, n-heptylbenzene, 1,3-di-isopropylbenzene, 1,4-di-isopropylbenzene, cyclohexylbenzene, tetralin and the like.

Examples of aromatic alcohol compounds include phenol, o-cresol, o-ethylphenol, m-cresol, p-cresol, p-ethylphenol, 4-methoxyphenol, o-n-propylphenol, o-isopropylphenol, o-s- Butyl phenol, o-t-butyl phenol, m-t-butyl phenol, p-t-butyl phenol, benzyl alcohol, etc. are mentioned.

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

Examples of the aromatic aldehyde-based compound include benzaldehyde.

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

As the organic solvent contained in the ink according to the present embodiment, an organic solvent having a boiling point of 250°C or higher is used. Organic solvents having such characteristics include aliphatic hydrocarbon compounds, aliphatic alcohol compounds, aliphatic ether compounds, aliphatic glycol compounds, aliphatic ester compounds, aliphatic aldehyde compounds, aliphatic ketone compounds, aliphatic carboxylic compounds, nitrogen Atom-containing aliphatic compound, sulfur-containing aliphatic compound, alicyclic compound, heteroatom-containing alicyclic compound, aromatic hydrocarbon compound, aromatic alcohol-based compound, aromatic ester-based compound, aromatic ether-based compound, aromatic aldehyde-based compound , aromatic carboxyl-based compounds, and the like.

As a more specific example of organic solvents having the above characteristics, triethylene glycol (boiling point 287 ° C.), tetraethylene glycol dimethyl ether (boiling point 275 ° C.), diethylene glycol dibutyl ether (boiling point 254 ° C.), ethylene glycol mono Benzyl ether (boiling point 256 ℃), tripropylene glycol (boiling point 268 ℃), 1,6-hexanediol (boiling point 250 ℃), thiodiglycol (boiling point 283 ℃), 2- (1-cyclohexenyl) cyclohexanone (boiling point 265 ℃), sulfolane (boiling point 285 ℃), n-octylbenzene (boiling point 261 ~ 263 ℃), n-nonylbenzene (boiling point 282 ℃), n-decylbenzene (boiling point 293 ℃), biphenyl (boiling point 255°C), dimethylnaphthalene (boiling point: 261 to 287°C), n-butyl benzoate (boiling point: 250°C), and phenylacetic acid (boiling point: 266°C) as an aromatic carboxylic compound.

Also, as the organic solvent contained in the ink according to the present embodiment, an organic solvent having a boiling point of 300°C or higher can be used. Organic solvents with such characteristics include dodecylbenzenebenzene (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 ℃), dibutyl phthalate (boiling point 341 ℃), dioctyl phthalate (boiling point 361 ℃), nonylphenol (boiling point 303 ℃), p-benzylphenol (boiling point 320 ℃), diphenylsulfone (boiling point 379 ℃) etc. can be mentioned.

The ink composition according to the present embodiment only needs to contain at least one organic solvent 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 adjusting the physical property values of the ink.

The content of the organic solvent with a boiling point of 250°C or higher contained in the ink composition according to the present embodiment is 20% based on the weight of the composition from the viewpoint of calculating the discharge amount from the image captured by the camera 31 and from the viewpoint of film formability and the like. It is preferable that it is more than % by weight. This is because, when the content of the organic solvent having the above characteristics is small, shooting errors tend to occur when measuring the discharge amount of ink.

In addition to the organic solvents described above, the ink composition may appropriately contain additives such as surfactants for surface conditioning and ultraviolet absorbers, light stabilizers and antioxidants for storage stability of the ink composition.

The organic solvent contained in the ink composition according to the present embodiment has a boiling point of 250°C or higher, preferably 280°C or higher, and more preferably 300°C or higher. The upper limit is preferably 400°C or less, more preferably 380°C or less, and particularly preferably 350°C or less. This is a boiling point assuming an environment in which the display panel D is manufactured by the inkjet device 1 according to the present embodiment. In short, the drying conditions of the ink are assumed. Therefore, depending on the use environment (measurement environment) of the inkjet device 1, the type and boiling point temperature of the high boiling point organic solvent used may be changed or adjusted.

The ink composition according to the present embodiment containing an organic solvent having a boiling point of 250°C or higher is preferably used for producing the display panel (D) itself. That is, through the ejection step, the acquisition step, and the derivation step, the ink ejection amount from the ink ejection head 23 of the inkjet device 1 is adjusted to an appropriate ejection amount, and the display panel (D) is used as it is. By manufacturing the ink ejection head 23, the discharge amount of ink from the ink ejection head 23 can be quickly transferred to the panel manufacturing process while maintaining the most appropriate ejection amount, which is preferable. When the ink used to adjust the discharge amount of ink from the ink ejection head 23 of the inkjet device 1 to an appropriate discharge amount through the ejection step, the acquisition step, and the derivation step is different from the ink used for panel manufacturing In this case, a cleaning process or an ink replacement process is required to replace the ink. Therefore, there are problems in that time is required, panel manufacturing cost is high, and a load is applied to the nozzles of the inkjet device 1 due to a cleaning process or a replacement process, so that the ink discharge amount may deviate from the adjusted discharge amount. .

[Flow of discharge amount measurement adjustment process]

The discharge amount measurement and adjustment step is performed by an ink discharge amount measurement and adjustment device having the inkjet device 1 . The discharge amount measurement adjustment step has a measurement adjustment method shown below.

[Measurement adjustment method]

The measurement adjustment method includes a measuring method for measuring the amount of droplets of ink ejected from the ink ejection head 23 described below. When the droplet amount of the ink measured by the measurement method deviates from the proper value, an adjustment method for adjusting to an appropriate value is required. Accordingly, the measurement adjustment method according to 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 method]

Next, a method for measuring the ejection amount of ink (hereinafter also referred to as "measurement method") performed in the inkjet apparatus 1 according to the present embodiment will be described. The measuring method according to the present embodiment is at least a necessary method for adjusting the discharge amount of ink performed in the inkjet device 1 according to the present embodiment. The measuring method according to the present embodiment is a method of measuring the discharge amount of ink from the ink ejection head 23, and here, the droplet amount of ink ejected from the ink ejection head 23 is not directly measured. It is indirectly measured by the flow of each step of a series of S602 to S605.

6 is a flow chart showing an example of the flow of the discharge amount measurement and adjustment process according to the present embodiment, and the discharge amount measurement process and discharge amount adjustment process according to the present embodiment described below. The discharge amount measurement and adjustment step is composed of a plurality of steps as shown in FIG. 6 . Each process shown in FIG. 6 may be started based on a user's instruction or may be started based on a predetermined operating condition. In addition, in order to simplify explanation, the flow of each process below is demonstrated as what the control apparatus 50 comprehensively controls.

(insertion process)

In measuring the discharge amount of ink from the ink ejection head 23, first, as a step of inserting the base material B1, the base material B1 is inserted at a predetermined starting position. In S601, the control device 50 controls the position of each part to the starting position of the measuring process described below, and then inserts the substrate B1 for measuring the discharge amount. It is assumed that the starting position of the measuring process according to this embodiment is the position of the stage 40 shown in FIG. 1 . In this position, the base material B1 can be inserted onto the stage 40. Also, it is assumed that the ink ejection head 23 is located on the transport path of the substrate B1 as shown in FIG. 2 . In addition, insertion of the substrate B1 into the stage 40 may be performed using a separately formed insertion device (not shown) or the like.

(discharge process)

The ejection step is a step of ejecting ink from the ink ejection head 23 onto the substrate B1 and making the ink land on the substrate B1. In S602, as shown in Fig. 7, the control device 50 moves the substrate B1 directly below the ink ejection head 23 to eject ink onto the substrate B1. Ejection of ink here may be performed simultaneously in all of the plurality of ink ejection heads 23, or may be performed sequentially in a predetermined order. Further, in the case of ejection, a discharge pattern for simultaneously ejecting from all nozzles may be used, or a predetermined ejection pattern for ejecting sequentially from each nozzle may be used. As described above, since the liquid-repellent coating material is applied to the surface of the base material B1, the discharged ink droplets 202 take a dome shape as shown in Fig. 9A. Here, the ink droplets after landing on the substrate (B1) are denoted as K.

(drying process)

The drying step is a step of stabilizing over a certain period of time so that the volume change due to drying of the organic solvent contained in the ink that has landed on the base material (B1) in the discharging step is almost eliminated. In S603, the control device 50 dries the ink droplets K on the substrate B1 as shown in FIG. 9A. As described above, the ink according to the present embodiment is constituted by containing an organic solvent that is difficult to evaporate (high boiling point solvent). Therefore, by providing a drying step for a certain period of time after landing on the base material B1, the volume of the ink droplet K is stabilized after the ink evaporates to a certain extent. In a stable state, there is little change in the diameter of the ink droplet K. This state is a state in which there is almost no change in the volume of the ink and the amount of the ink is maintained at a constant ratio. By photographing the ink droplet K after stabilizing the volume of the ink in this way, the ink droplet amount can be measured with good accuracy. 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 more as a predetermined time, more preferably 10 minutes or more. In addition, as shown in Fig. 1, when a plurality of ink ejection heads 23 are provided, and each corresponds to an ink having a different composition, the drying step in S603 corresponds to the composition of each ink. Drying time is also adjusted.

The form of the drying process is not particularly limited as long as a predetermined time can be set until the shooting process at the later stage. For example, drying may be performed while the base material B1 is stopped immediately below the ink ejection head 23, or a configuration in which a predetermined time elapses while moving to the photographing position by the camera 31 may be used. Alternatively, drying may be performed at a photographing position by the camera 31 . In this embodiment, drying is natural drying, and no special temperature or humidity adjustment is performed, but at least the drying time during drying is measured.

(acquisition process)

The acquisition step is a step of acquiring an image of the ink ejected onto the substrate (B1). In S604, the controller 50 moves the base material B1 directly below the camera 31 as shown in FIG. 8 to take a picture of the base material B1, and ejects An image containing ink is acquired. Fig. 8 is a schematic diagram showing the state of the substrate (B1) at the time of imaging. 9A is a view of the camera 31 periphery at the time of imaging viewed from the side along the X-axis direction, and FIG. 9B is a view of the base material B1 to be photographed viewed from the top side along the Z-axis direction. 8, 9A, and 9B show an example in which an ink droplet K is photographed for each line in the sub-scan direction, but is not limited thereto. Depending on the angle of view of the camera 31, resolution, etc., a plurality of lines of ink droplets K may be collectively photographed. From the viewpoint of time reduction, it is preferable to collectively photograph a plurality of ink droplets K in one photograph using a high-angle, high-resolution camera, and to capture all of the ink droplets K ejected on the substrate B1. It is most desirable to be able to shoot at one time.

(Derivation process)

The derivation step is a step of deriving the discharge amount of each nozzle of the ink ejected from the nozzles of the ink ejection head 23 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 from the image, and derives the diameter of the ink droplet K. In addition, the controller 50 derives the ejection amount of ink from the derived diameter of the ink droplet K.

In this embodiment, the discharge amount of ink is derived based on the diameter of the ink droplet K. Since the liquid-repellent coating material is applied to the substrate (B1), the ink does not permeate into the substrate (B1). On the other hand, in the drying step of S603, the ink is dried and its volume is changed by a certain amount. As shown in Fig. 4, the ink according to the present embodiment has a stable volume after constant drying. Therefore, the discharge amount of the ink discharged from the nozzle can be derived based on the volume of the ink after stabilization and the rate of change in the volume of the ink according to the composition of the ink. In addition, since the time until the volume of the ink is stabilized by drying varies depending on the composition of the ink and the surrounding environment, it is not limited to the above. In this embodiment, it is preferable that the ambient environment (temperature or humidity) at the time of manufacturing the organic EL display panel is constant.

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 base material B1 coated with the liquid-repellent coating material differs depending on the amount of ink as well as the surface tension or contact angle defined by the composition of the ink. Therefore, a table defining the relationship between the diameter and the volume on the substrate (B1) corresponding to the ink to be used is used. The method of deriving the volume of the ink droplet K from the diameter of the ink droplet K is not limited to this. For example, a formula corresponding to the composition of the ink may be defined, 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 provided in the ink ejection head 23 . Further, in this step, the control device 50 may be configured to perform image processing on an image picked up by the camera 31 . For example, in order to detect the diameter of the ink droplet K with better precision, a configuration may be performed in which edge processing or filter processing is performed. By each step of S602 to S605 up to this point, the ejection amount of the ink is measured.

[adjustment method]

The measurement adjustment method according to the present embodiment preferably has an adjustment method including an adjustment step described below after performing the measurement method including the above measurement step. In the present embodiment, as a result of measuring the amount of ink discharged by the inkjet device 1 by the measuring method having the above measuring step, if the amount of ink discharged is out of the appropriate value, the discharged amount of ink is set to an appropriate value. An adjustment process to adjust is required. In addition, as a result of measuring the discharge amount of ink performed in the inkjet device 1 by the measuring method having the above measurement step, if the discharge amount of ink is an appropriate value, the adjustment step is unnecessary.

(adjustment process)

The adjusting step is a step of adjusting the ejection amount of ink from the ink ejection head 23 derived in the measuring step (S602 to S605) to an appropriate amount. In S606, the controller 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. Adjustment here may include detection of nozzles in which ink is not ejected, in addition to the increase or decrease in the ejection amount of ink.

(discharge process)

In S607, the controller 50 discharges the substrate B1. The discharge position of the base material (B1) may be the same as the insertion position of the base material (B1), or may be on the downstream side of the conveyance direction of the base material (B1). In addition, discharging of the substrate B1 from the stage 40 may be performed using a separately formed discharging device (not shown) or the like. Usually, this discharge process is executed after the final process of a measurement process or an adjustment process, ie, a measurement process and an adjustment process are normally completed. And the flow of this discharge amount measurement adjustment process ends.

In the above example, the configuration in which the discharge amount of ink is measured by one discharge from each nozzle of the ink discharge head 23 and the discharge amount is adjusted is shown. The measurement adjustment method according to the present embodiment is not limited to this configuration, and may have a configuration in which adjustment precision is improved by repeating the steps of S602 to S606 a plurality of times. Further, when a nozzle that does not eject ink occurs as a result of the adjustment, the configuration may notify information about the nozzle.

When the steps of S602 to S606 are repeated a plurality of times, it is preferable to complete the steps in a short time, and the number of repetitions of the steps of S602 to S606 is preferably small. The number of repetitions is usually 10 times or less, preferably 5 times or less, more preferably 3 times or less, particularly preferably 2 times or less, and from the viewpoint of short time, 1 time is most preferable. After the steps of S602 to S606 are performed once to adjust the discharge amount of ink from the ink ejection head 23, from the viewpoint of confirmation, it is preferable that the steps are performed once again and twice. In the case of carrying out twice or more, in the second and subsequent measuring steps, if the discharged amount of the derived ink is an appropriate value, the step of S606 may not be performed.

In addition, in the case where the same type of panel is manufactured with the same type of ink over a long period of time, since the data of the measurement process and the adjustment process are accumulated, the series of measurement processes and adjustment processes of S602 to S606 are performed only once. Alternatively, from the viewpoint of confirming the discharge amount of ink from the ink ejection head 23 after the adjustment step, it is preferable to perform the measurement step once after the series of measurement steps and adjustment steps of S602 to S606. Further, if the discharge amount of ink from the ink ejection head 23 derived in the measurement step is an appropriate amount, the adjustment step is unnecessary. In this case, it may proceed to the discharging step of the next substrate (B1), or the measurement step may be performed again to reconfirm that the amount of ink ejected from the ink ejection head 23 is an appropriate amount.

If the discharge amount of ink from the ink ejection head 23 derived in the above measuring step is an appropriate amount, the measuring step is not carried out again and proceeding to the next substrate (B1) discharging step (S607) is the discharge amount measurement adjustment. It is preferable from the viewpoint of time reduction in the entire process. On the other hand, even if the discharge amount of ink from the ink discharge head 23 derived in the measurement step is an appropriate amount, it is better to perform the measurement step again to reconfirm that the discharge amount of ink from the ink discharge head 23 is an appropriate amount. It can be confirmed that there is no variation or error in the discharge amount due to unexpected disturbance factors, which is preferable from the viewpoint of enabling production with a higher yield.

In the above measurement process, since a certain period of time needs to pass in the drying process (S603), when the measurement process is repeated a plurality of times, a long time elapses, which is not preferable in terms of production. Therefore, in the above measuring step, it is preferable to perform the measuring step by ejecting a plurality of ink droplets from one nozzle to different positions on the substrate B1. This method is preferable because it is possible to reduce the influence of variations and errors in the discharge amount due to unexpected disturbance factors in a single measurement step even if multiple discharges are performed. In the case where the measurement step for confirmation is performed again after the subsequent adjustment step (S606), similarly, it is preferable to eject a plurality of ink droplets from one nozzle to different positions on the substrate B1.

As described above, the high boiling point solvent is contained in the ink according to the present embodiment. Since the high boiling point solvent does not evaporate at room temperature (that is, under the manufacturing environment of the display panel D), the change in the diameter of the ink droplet K after the solvent becomes only the high boiling point solvent is virtually eliminated. 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 amount can be accurately converted from the diameter of the ink droplet K. As a result, it is possible to appropriately measure the discharge amount of each nozzle of the ink discharge head 23 . In addition, the discharge amount of the nozzles in the ink discharge head 23 can be appropriately adjusted, and also when the ink is discharged to the base material B2 when manufacturing the display panel D, it is natural due to the influence of the high boiling point solvent. Drying can also be suppressed. As a result, when manufacturing the display panel (D), it becomes possible to appropriately carry out the drawing process with respect to the base material (B2) without unevenness in film thickness.

[Relationship between discharge amount measurement and adjustment process and panel manufacturing process]

The panel manufacturing system of the organic EL display panel according to the present embodiment includes the discharge amount measurement and adjustment device and an organic EL display panel manufacturing device using the ink discharge head 23 of the discharge amount measurement and adjustment device. After the discharge amount measurement and adjustment step shown in Fig. 6 is completed, the organic EL display panel is manufactured. In this case, instead of the base material B1, the base material B2 is inserted into the stage 40 and panel production is performed. Since the discharge amount of ink also differs depending on the lot of the ink discharge head 23, for example, in manufacturing the organic EL display panel, the ink discharge head 23 that has completed the discharge amount measurement and adjustment step shown in FIG. need to use Incidentally, the timing at which the adjustment operation shown in Fig. 6 is executed may be arbitrary. For example, you may carry out before manufacturing the 1st base material (B2) in a lot unit at the time of manufacturing an organic electroluminescent display panel. Alternatively, it may be carried out for each substrate (B2) when manufacturing the organic EL display panel. In addition, when a plurality of ink ejection heads 23 are formed corresponding to each of a plurality of layers constituting the organic EL display panel, each ink ejection head 23 corresponding to each layer individually measures and adjusts the ejection amount shown in FIG. The process may be performed, or the ejection amount measurement and adjustment process shown in FIG. 6 may be performed collectively for the ink ejection head 23 corresponding to each layer.

In addition, even after replacing or cleaning the ink ejection head 23, it is necessary to carry out the ejection amount measurement and adjustment process shown in FIG. The reason is that when the ink ejection head 23 is replaced, initial adjustment of all nozzles of the ink ejection head 23 is required. This is because, in the case of washing, there is a possibility of affecting the discharge amount of ink due to unexpected, minute deformation of a part below the detection limit and/or undetectable part, or slight misalignment of parts. Furthermore, it is necessary to carry out the ejection amount measurement adjustment step of FIG. 6 even when the ink is replaced by any method even for the same type of ink. This is because even with the same type of ink, there is a possibility that a slight variation in the liquid properties of the ink may affect the variation in the discharge amount from the ink ejection head 23, for example, when the lot is different. .

As described above, since the discharge amount of ink may vary depending on the lot of the ink or the replacement of the ink, in the manufacture of the organic EL display panel, the ink for which the discharge amount measurement and adjustment step shown in FIG. 6 has been completed is used as it is. it is desirable In addition, when the ink that has completed the discharge amount measurement and adjustment step shown in Fig. 6 is used as it is, the following state is exhibited. That is, the ink ejected from the plurality of nozzles formed in the ink ejection head 23 is normally connected to the ink ejection head 23 by an ink reservoir (not shown) mounted on the ink ejection head 23 or a pipe. The ink is continuously supplied to the ink ejection head 23 from an ink reservoir (not shown). Using the ink that has completed the discharge amount measurement and adjustment process shown in FIG. 6 as it is means that after completion of the discharge amount measurement and adjustment process shown in FIG. is to use In this way, after completion of the ejection amount measurement and adjustment process shown in FIG. 6, it is possible to transfer to the panel manufacturing process without a slight change in physical properties of the ink, so that the ink ejection head 23 adjusted to an appropriate ejection amount can stably produce a panel. It can be manufactured, which is preferable.

In addition, although it is described here as "a discharge amount measurement and adjustment process shown in FIG. 6", this is a simple name of a process and does not indicate the contents of the process in words. That is, when it is confirmed that the discharge amount is appropriate through the above measuring steps (S602 to S605), even when the above adjustment step (S606) is not performed, it is included in the "discharge amount measurement and adjustment step shown in FIG. 6" will be.

[Configuration of display panel (D)]

Subsequently, the display panel D that can be manufactured using the method for measuring the discharge amount of ink or the method for adjusting the discharge amount of ink described above will be described with reference to FIGS. 10 to 12 . 10 is a schematic plan view showing a configuration example of the display panel D according to the present embodiment. 10 is a schematic diagram, and the scale may differ from the actual one.

The display panel (D) according to the present embodiment is an organic EL display panel using an electroluminescence phenomenon of an organic compound. In the display panel D, a plurality of organic EL display elements each constituting a pixel are arranged in a matrix on a substrate on which thin film transistors (TFTs) are formed (hereinafter referred to as a "TFT substrate"), It has a top emission type configuration in which 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 a row direction, a column direction, and a thickness direction in the display panel D, respectively.

As shown in FIG. 10 , the display panel D according to the present embodiment includes a partitioned area 10a and a non-partitioned area 10b located around the partitioned area 10a. The partitioned area 10a is partitioned on the substrate 100 in a matrix form by banks 122 that regulate light emitting units of each color (here, three colors of RGB). In addition, the bank 122 along the Y-axis direction is referred to as a column bank 122Y, and the bank along the X-axis direction is referred to as a row bank 122X.

A rectangular sealing member 300 surrounding the partitioned area 10a is formed in the non-partitioned area 10b. The partitioned region 10a is composed of a display pixel array region 10e covering the center of the substrate 100 and a non-emission region 10ne located around the display pixel array region 10e. The display pixel arrangement region 10e is a region in which organic EL display elements are formed in each section regulated by the column bank 122Y and the row bank 122X. On the other hand, the non-emission region 10ne is a region in which no organic EL display element is formed.

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

Further, as shown in FIG. 11 , a plurality of pixel electrodes 119 are arranged on the substrate 100 in a row and column direction separated by a predetermined distance from each other. The pixel electrodes 119 arranged in a matrix form correspond to the self-luminous regions 100aR, 100aG, and 100aB arranged in order in the row direction. In addition, a region other than the self-emission region 100a becomes a non-self-emission region 100b. In the non-self-luminous region 100b, a contact hole 119c connecting the pixel electrode 119 and the source of the TFT is formed. Further, in the non-self-luminous region 100b, a contact region 119b for electrical connection to the pixel electrode 119 is formed.

Fig. 12 is a schematic cross-sectional view of a position taken along line X1-X1 shown in Fig. 11 . As shown in Fig. 12, the display panel D according to the present embodiment is composed of a substrate 100 (TFT substrate) on which thin film transistors are formed below in the Z-axis direction, and an organic EL element portion as a light emitting element portion is formed thereon. Consists of. The organic EL element portion is composed of a plurality of layers, and the inkjet device 1 described above can be applied when forming a part of these layers. As a plurality of layers constituting the organic EL element portion, 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, and a counter electrode 125 ), an encapsulation layer 126, a bonding layer 127, and a color filter substrate 131 are included. Also, the color filter substrate 131 includes a color filter layer 128 and an upper substrate 130 . Hereinafter, the part constituting the display panel D will be described.

(substrate (TFT substrate))

The substrate 100 is a support member of the display panel D, and includes a substrate (not shown), a thin film transistor (TFT) layer (not shown) formed on the substrate, and an interlayer insulating layer formed on the substrate and on the TFT layer ( not shown).

A substrate (not shown) constituting the substrate 100 is a support member for the display panel D, and is flat. As the material of the substrate, a material having electrical insulation, for example, 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, a glass substrate, a quartz substrate, a silicon substrate, a metal substrate such as molybdenum sulfide, copper, zinc, aluminum, stainless steel, magnesium, iron, nickel, gold, silver, a semiconductor substrate such as a gallium arsenide substrate, a plastic substrate, etc. It can be employed as a base material.

A TFT layer (not shown) constituting the substrate 100 is composed of a plurality of TFTs and wirings formed on the upper surface of the substrate. The TFT electrically connects a pixel electrode 119 corresponding to itself and an external power supply (not shown) in response to a drive signal from an external circuit of the display panel D, and is a component of an electrode, a semiconductor layer, an insulating layer, and the like. It consists of a multi-layered structure. Wiring (not shown) electrically connects the TFT, the pixel electrode 119, an external power supply, an external circuit, and the like. The interlayer insulating layer located on the upper surface of the substrate 100 flattens at least a part of the upper surface of the substrate 100 having irregularities by means of a TFT layer. Moreover, the interlayer insulating layer fills in between the wiring and the TFT, and electrically insulates between the wiring and the TFT.

For the interlayer insulating layer, for example, silicon oxide (SiO2), silicon nitride (SiN), silicon oxynitride (SiON), silicon oxide (SiO), and silicon oxynitride (SiON) can be used. As the connection electrode layer of the TFT, for example, a laminate of molybdenum (Mo), copper (Cu), and copper manganese (CuMn) can be employed. The interlayer insulating layer is formed using, for example, organic compounds such as polyimide-based resin, acrylic resin, siloxane-based resin, and novolak-type phenolic resin, and has a layer thickness of, for example, 2000 nm to 8000 It can be set as the range of nm.

(pixel electrode)

A pixel electrode 119 is formed on an interlayer insulating layer (not shown) located on the upper surface of the substrate 100 . The pixel electrode 119 is for supplying carriers to the light emitting layer 123, and supplies holes to the light emitting layer 123 when functioning as an anode, for example. The pixel electrode 119 is a flat plate with a rectangular shape. In addition, through a contact hole opened on the upper surface of the substrate 100, a portion of the pixel electrode 119 is recessed in the direction of the substrate 100, and the connection concave portion of the pixel electrode 119 and the source of the TFT are connected. connected

The pixel electrode 119 is made of a metal material. In the case of a top emission type organic EL display panel, the chromaticity of emitted light is adjusted to increase luminance by adopting an optical resonator structure with an optimum layer thickness. Therefore, the surface portion of the pixel electrode 119 has high reflectivity. The pixel electrode 119 may 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 a metal layer, it can be comprised from the metal material containing silver (Ag) or aluminum (Al), for example. Examples of the alloy layer include APC (an alloy of silver, palladium, and copper), ARA (an alloy of silver, rubidium, and gold), MoCr (an alloy of molybdenum and chromium), and NiCr (an alloy of nickel and chromium). can be used As a constituent material of the transparent conductive layer, indium tin oxide (ITO), indium zinc oxide (IZO), or the like can be used, for example.

(hole injection layer, hole transport layer)

On the pixel electrode 119, a hole injection layer 120 and a hole transport layer 121 are stacked in this order, and the hole transport layer 121 is in contact with the hole injection layer 120. The hole injection layer 120 and the hole transport layer 121 have a function of transporting holes injected from the pixel electrode 119 to the light emitting layer 123 .

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

As the conductive polymer material that can be used as the hole injection layer 120 or the hole transport layer 121, polyvinylcarbazole or a derivative thereof, polysilane or a derivative thereof, a polysiloxane derivative having an aromatic amino group in a side chain or a main chain, pyra zoline derivatives, arylamine derivatives, stilbene derivatives, triphenyldiamine derivatives, polyaniline or its derivatives, polythiophene or its derivatives, polypyrrole or its derivatives, poly(p-phenylenevinylene) or its derivatives, or poly(2 ,5-thienylenevinylene) or derivatives thereof, and the like. Specifically, as a hole transport material, Japanese Unexamined Patent Publication No. 63-70257, Japanese Unexamined Patent Publication No. 63-175860, Japanese Unexamined Patent Publication No. 2-135359, Japanese Unexamined Patent Publication No. 2-135361, Japan What is described in Unexamined-Japanese-Patent No. 2-209988, Unexamined-Japanese-Patent No. 3-37992, and Unexamined-Japanese-Patent No. 3-152184 etc. are illustrated.

Among these, as the hole transport material used for the hole transport layer 121, polyvinylcarbazole or a derivative thereof, polysilane or a derivative thereof, a polysiloxane derivative having an aromatic amino group in the side chain or main chain, polyaniline or a derivative thereof, A polymeric hole transport material such as opene or a derivative thereof, poly(p-phenylenevinylene) or a derivative thereof, or poly(2,5-thienylenevinylene) or a derivative thereof is preferred, more preferably polyvinylcaric acid. Bazol or a derivative thereof, polysilane or a derivative thereof, or a polysiloxane derivative having an aromatic amino group in a side chain or a main chain. In the case of a low-molecular hole transport material, it is preferable to use it after being dispersed in a high-molecular binder.

Polyvinylcarbazole or its derivative(s) is obtained by cationic polymerization or radical polymerization from a vinyl monomer, for example. As the polysiloxane or a derivative thereof, one having the structure of the hole transport material described above in a side chain or a main chain in a siloxane skeleton structure is preferably used. In particular, those having a hole-transporting aromatic amino group in the side chain or main chain are exemplified.

The hole injection layer 120 and the hole transport layer 121 can be formed using the inkjet device 1 shown in FIG. 1 . As the ink for forming the hole injection layer 120 or the hole transport layer 121, the organic solvent to be used is not particularly limited as long as it dissolves the hole injection material or the hole transport material.

(bank)

A bank 122 made of an insulating material is formed so as to cover the edge of the pixel electrode 119, the hole injection layer 120, and the hole transport layer 121. The bank 122 has a volume resistivity of 1 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. It is preferable to have insulation of 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 for forming the bank 122 include acrylic resins, polyimide resins, and novolak-type phenolic resins. The bank 122 preferably has resistance to organic solvents. More preferably, it is preferable to use acrylic resin. It is because acrylic resin has a low refractive index and is suitable as a reflector.

When using an inorganic material for the bank 122, it is preferable to use, for example, silicon oxide (SiO) from the viewpoint of refractive index. Alternatively, the bank 122 is formed using, for example, an inorganic material such as silicon nitride (SiN) or silicon oxynitride (SiON).

In addition, since the bank 122 may be subjected to an etching process, a baking process, or the like during the panel manufacturing process, it is preferable to be formed of a material having high resistance to these processes, such as not being excessively deformed or deteriorated. . Further, in order to impart liquid repellency to the surface, the surface of the bank 122 may be treated with fluorine by CVD (Chemical Vapor Deposition) or the like.

(light emitting layer)

A light emitting layer 123 emitting light in each color is formed on the display panel D. Specifically, the color here includes three colors of R (Red), G (Green), and B (Blue). The light-emitting layer 123 is a layer made of an organic compound, and has a function of emitting light when holes and electrons recombine therein. In the light emitting layer 123, only a portion to which carriers are supplied from the pixel electrode 119 emits light. The light-emitting layer 123 can be formed using the inkjet device 1 shown in FIG.

The material used for formation of the light-emitting layer 123 needs to use a light-emitting organic material that can be formed into a film using a wet printing method. The light emitting layer 123 may be a layer made of a known material that can be used for the light emitting layer (layer having a function of emitting light) of the organic EL element portion, and the material is not particularly limited. desirable. For example, it is preferable to use a layer formed of an organic substance (low-molecular compound and high-molecular compound) that emits fluorescence or phosphorescence as a luminescent material, and a dopant to assist this.

Examples of such a luminescent material (an organic substance that emits fluorescence or phosphorescence) include a dye-based material, a metal complex-based material, and a polymer-based material. Examples of such pigment-based materials include cyclopentamine derivatives, tetraphenylbutadiene derivative compounds, triphenylamine derivatives, oxadiazole derivatives, pyrazoloquinoline derivatives, distyrylbenzene derivatives, distyrylarylene derivatives, and pyrroles. derivatives, thiophene ring compounds, pyridine ring compounds, perinone derivatives, perylene derivatives, oligothiophene derivatives, oxadiazole dimers, pyrazoline dimers and the like.

Examples of the metal complex material include aluminum quinolinol complexes, benzoquinolinol beryllium complexes, benzoxazolyl zinc complexes, benzothiazol zinc complexes, azomethyl zinc complexes, porphyrin zinc complexes, and europium complexes. , having a rare earth metal such as aluminum (Al), zinc (Zn), beryllium (Be), or terbium (Tb), europium (Eu), or dysprosium (Dy) as a central metal, and oxadiazole or thiadiazole as a ligand , phenylpyridine, phenylbenzoimidazole, metal complexes having a quinoline structure, and the like.

Further, as the polymeric material, polyparaphenylenevinylene derivatives, polythiophene derivatives, polyparaphenylene derivatives, polysilane derivatives, polyacetylene derivatives, polyfluorene derivatives, polyvinylcarbazole derivatives, the above-mentioned pigments, and those obtained by polymerizing a metal complex light emitting material.

Among such luminescent materials, materials emitting blue light include distyrylarylene derivatives, oxadiazole derivatives, and polymers thereof, polyvinylcarbazole derivatives, polyparaphenylene derivatives, and polyfluorene derivatives. . Among them, polyvinylcarbazole derivatives, polyparaphenylene derivatives, and polyfluorene derivatives of polymeric materials are preferable.

Moreover, as a luminescent material which emits green light, quinacridone derivatives, coumarin derivatives, their polymers, polyparaphenylenevinylene derivatives, polyfluorene derivatives, etc. are mentioned. Among them, polyparaphenylenevinylene derivatives and polyfluorene derivatives of polymeric materials are preferred.

Moreover, examples of luminescent materials emitting red light include coumarin derivatives, thiophene ring compounds, and polymers thereof, polyparaphenylenevinylene derivatives, polythiophene derivatives, and polyfluorene derivatives. Among them, polyparaphenylenevinylene derivatives, polythiophene derivatives, polyfluorene derivatives and the like of polymeric materials are preferred.

In addition, the manufacturing method of such a luminescent material is not specifically limited, A well-known method can be employ|adopted suitably, You may employ the method of Unexamined-Japanese-Patent No. 2012-144722, for example.

In addition, it is preferable to add a dopant to the ink used when forming the light-emitting layer 123 for the purpose of improving the light-emitting efficiency or changing the light-emitting wavelength. Examples of such dopants include perylene derivatives, coumarin derivatives, rubrene derivatives, quinacridone derivatives, squarylium derivatives, porphyrin derivatives, styryl pigments, tetracene derivatives, pyrazolone derivatives, decacyclene, A phenoxazone etc. are mentioned. In addition, it is preferable that the thickness of such a light emitting layer 123 is usually about 20 to 2000 Å.

The film shape of the light-emitting layer 123 formed by using an ink containing an organic solvent having a high boiling point of 250°C or higher, preferably 300°C or higher, has the same film thickness at the periphery and at the center of the film formation area. It becomes a human form. That is, with the ink according to the present embodiment, it is possible to suppress film thickness fluctuations caused by unbalance of the solvent evaporation rate accompanying the vapor concentration distribution of the ink solvent in the central portion and the peripheral portion of the substrate.

(electron transport layer)

An electron transport layer 124 is formed on the light emitting layer 123 on the bank 122 and in the opening defined by the bank 122 . The electron transport layer 124 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.

(opposite electrode)

A counter electrode 125 is laminated so as to cover the electron transport layer 124 . The counter electrode 125 is formed continuously over the entire display panel D, and may be connected to bus bar wiring in units of pixels or units of several pixels (not shown). The counter electrode 125 serves as a pair with the pixel electrode 119 to form a conduction path by interposing the light emitting layer 123 therebetween, and supplies carriers to the light emitting layer 123 . When the counter electrode 125 functions as a cathode, for example, it supplies electrons to the light emitting layer 123 . The counter electrode 125 is formed along the surface of the electron transport layer 124 and serves as an electrode common to each of the light emitting layers 123 formed between the banks 122 . For the counter electrode 125, a conductive material having light transmission is used. For example, the counter electrode 125 is formed using indium tin oxide (ITO) or indium zinc oxide (IZO). Also, an electrode made of a thin film of silver (Ag) or aluminum (Al) or the like may be used as the counter electrode 125 .

(encapsulation layer)

A sealing layer 126 is laminated to cover the counter electrode 125 . The sealing layer 126 is formed to suppress deterioration of the light emitting layer 123 in contact with moisture or air. The sealing layer 126 is formed over 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, for example, a light-transmitting material such as silicon nitride (SiN) or silicon oxynitride (SiON). Alternatively, an encapsulating resin layer made of a resin material such as an acrylic resin or a silicone resin may be formed on a layer formed using a material such as silicon nitride (SiN) or silicon oxynitride (SiON).

(bonding layer)

Above the sealing layer 126 in the Z-axis direction, a color filter substrate 131 composed of an upper substrate 130 and a color filter layer 128 is disposed, and the sealing layer 126 and the color filter substrate 131 are bonded. They are joined by layer 127. The bonding layer 127 bonds the back panel composed of each layer from the substrate 100 to the sealing layer 126 and the color filter substrate 131, and prevents each layer from being exposed to moisture or air. has a function As the material of the bonding layer 127, for example, a translucent resin material such as an acrylic resin, a silicone resin, or an epoxy resin can be employed.

(upper board)

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

(color filter layer)

On the color filter substrate 131, a color filter layer 128 corresponding to each color is formed at a position corresponding to a light emitting region of a pixel. The light emitting region corresponds to the position of the light emitting layer 123 formed between the banks 122 . The color filter layer 128 is a transparent layer formed to transmit visible light of a wavelength corresponding to each color (eg, R, G, and B), transmits light emitted from each color pixel, and corrects the chromaticity. has a function to Specifically, the color filter layer 128 is formed by applying ink containing a color filter material and a solvent to an upper substrate 130 made of a cover glass for forming a color filter in which a plurality of openings are formed in a matrix in pixel units. It is formed by the process of

[Panel manufacturing process of display panel (D)]

Next, the panel manufacturing process of the display panel D will be described with specific examples. Among the configurations of the display panel D shown in Figs. 10 to 12, the light emitting layer 123, the hole injection layer 120, and the hole transport layer 121 can be formed by an inkjet method. Therefore, in the present embodiment, the method for measuring the ejection amount of ink or the method for adjusting the ejection amount of ink described with reference to FIG. 6 will be described as being used when these three layers are formed. Therefore, the panel manufacturing system of the display panel D according to the present embodiment includes a display panel manufacturing apparatus that manufactures the display panel D itself, as well as the above-described ink ejection amount measuring and adjusting apparatus. It is desirable to be 13 is a flowchart showing a panel manufacturing process of the display panel (D).

In this embodiment, an ink ejection head 23 corresponding to each layer is provided. In short, the structure shown in FIG. 1 is prepared to form each of the light emitting layer 123, the hole injection layer 120, and the hole transport layer 121. In addition, in order to simplify explanation, the process for manufacturing the display panel D is demonstrated assuming that the control device 50 controls comprehensively. When this panel manufacturing process flow starts, the substrate 100 constituted by the base material, the TFT layer, and the interlayer insulating layer is prepared.

(S1301)

In S1301 , the control device 50 forms the pixel electrode 119 on the substrate 100 . Specifically, contact holes (not shown) are provided in the interlayer insulating layer of the substrate 100 to form the pixel electrodes 119 . The formation of the pixel electrode 119 is performed by forming a metal film using a sputtering method or a vacuum deposition method, and then patterning using a photolithography method and an etching method. In addition, the pixel electrode 119 is electrically connected to the electrode of the TFT constituting the substrate 100 .

(S1302)

In S1302, the control device 50 forms the bank 122. In the formation of the bank 122, the bank 122 is formed along a predetermined direction, and then a bank in a direction orthogonal to the predetermined direction is formed. The formation of the bank 122 is formed by laminating a film made of a constituent material of the bank 122 (for example, a photosensitive resin material). Then, the resin film is patterned to sequentially form banks. Patterning of the banks may be performed by exposing the resin film above the resin film using a photomask, followed by a developing step and a firing step (for example, at about 230°C for about 60 minutes).

In the step of forming the bank 122, first, a photosensitive resin film made of an organic photosensitive resin material such as an acrylic resin, a polyimide resin, a novolak-type phenolic resin, or the like is formed using a spin coating method or the like. do. After that, drying is performed to volatilize the solvent to some extent, and then a photomask having predetermined openings formed thereon is superimposed. Further, ultraviolet irradiation is performed thereon to expose a photoresist made of a photosensitive resin or the like, and the pattern of the photomask is transferred to the photoresist. Subsequently, an insulating layer patterned on the bank 122 is formed by developing a photosensitive resin. Generally, a photoresist called a positive type is used. In the positive type, the exposed portion is removed by development. Portions of the mask pattern that are not exposed are not developed and the bank 122 remains at a certain thickness.

(S1303)

In S1303 , the control device 50 laminates and forms the hole injection layer 120 on the pixel electrode 119 . The hole injection layer 120 can be formed by an inkjet method using ink in which a conductive polymer material is dissolved in an organic solvent. In the present embodiment, when forming the hole injection layer 120, first, the discharge amount of each nozzle of the ink discharge head 23 is adjusted by the method shown in FIG. 6 with the ink discharge amount measurement and adjustment device described above. At this time, the base material (B1) inserted in the insertion step (S601) of FIG. 6 is a base material coated with a liquid repellent coating material having liquid repellency to the ink used when forming the hole injection layer 120. . Then, after the adjustment of the discharge amount is completed, the hole injection layer 120 is formed at a predetermined position defined by the bank 122 with ink containing a conductive polymer material by using an inkjet method.

(S1304)

In S1304 , the control device 50 laminates and forms the hole transport layer 121 on the hole injection layer 120 . The hole transport layer 121 can be formed by an inkjet method using ink in which a conductive polymer material is dissolved in an organic solvent. In the present embodiment, when forming the hole transport layer 121, first, the discharge amount of each nozzle of the ink discharge head 23 is adjusted by the method shown in FIG. 6 with the above ink discharge amount measurement and adjustment device. At this time, the base material B1 inserted in step S601 of FIG. 6 is a base material coated with a liquid repellent coating material having liquid repellency to the ink used when forming the hole transport layer 121. 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 ink containing a conductive polymer material by using an inkjet method.

(S1305)

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

(S1306)

In S1306 , the control device 50 laminates and forms the electron transport layer 124 on the light emitting layer 123 . The electron transport layer 124 can be formed using a vacuum deposition method or the like. In the case of forming the electron transport layer 124 by a wet method, the discharge amount of each nozzle of the ink discharge head 23 is adjusted by the method shown in FIG. It is preferable to perform step (S606).

(S1307)

In S1307, the controller 50 stacks and forms the counter electrode 125 so as to cover the electron transport layer 124 as a solid film. The counter electrode 125 can be formed using a CVD method, a sputtering method, or the like.

(S1308)

In S1308, the controller 50 laminates and forms the sealing layer 126 so as to cover the counter electrode 125 as a solid film. Like the counter electrode 125, the sealing layer 126 can be formed using a CVD method, a sputtering method, or the like.

(S1309)

In S1309, the control device 50 forms the color filter substrate 131. In formation of 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 (e.g., G) containing an ultraviolet curable resin component as a main component is dispersed in a solvent, a paste is applied, and the solvent is removed to a certain extent, A predetermined pattern mask is placed and ultraviolet irradiation is performed. After that, when curing is performed, the pattern mask and the uncured paste are removed and developed, the color filter layer (G) is formed. By repeating this process in the same way for each color filter material, the color filter layers (R) and (B) are formed. In addition, you may use a commercially available color filter product instead of using a paste. In addition, the color filter substrate 131 may be formed in advance, and in this step, only the color filter substrate 131 having been formed may be installed.

(S1310)

In S1310, the control device 50 attaches the color filter substrate 131 and the rear panel. In this step, first, the material of the bonding layer 127 containing an ultraviolet curable resin such as acrylic resin, silicone resin, and epoxy resin as a main component is applied to the back panel composed of each layer from the substrate 100 to the sealing layer 126 to spread Subsequently, the applied material is irradiated with ultraviolet rays, and both substrates are bonded in a state in which the relative positional relationship between the back panel and the color filter substrate 131 is matched. At this time, bonding is performed so that gas does not enter between them. Thereafter, the display panel D is completed by firing both substrates to complete the sealing process. And this panel manufacturing process is complete|finished.

In addition, in the above example, when forming the three layers of the light emitting layer 123, the hole injection layer 120, and the hole transport layer 121, the inkjet method is used, and at that time, the ink discharge amount measurement and adjustment device described above According to the method shown in Fig. 6, the amount of discharged ink according to the present embodiment is measured and adjusted. However, it is not limited to these layers, and a structure applied to at least one layer of the layers constituting the display panel D may be used. Therefore, in the case where the inkjet method can be used when forming other layers, the method for measuring and adjusting the discharge amount of ink according to the present embodiment may be applied when forming those layers.

[verification example]

Verification results using the method related to the present embodiment will be described below. In the present embodiment, verification is performed using three compositions 1 to 3 having characteristics related to the present embodiment and five examples of two comparative compositions 1 and 2 as comparative examples, and the comparison results are shown. Here, taking the ink used when forming the hole injection layer 120 as an example, it is assumed that the same functional material is used for all inks. 14A is a table diagram summarizing the composition of each composition.

(composition 1)

In the ink composition 1, a functional high molecular compound having a repeating structure of the following formula P1 as a functional material, a charge transport material, and 4-isopropyl-4'-methyldiphenyliodonium tetrakis (pentafluorocarbon) as an electron-accepting compound. A mixture of lophenyl)borate in a ratio of 5:1 is used. Moreover, composition 1 uses the organic solvent mixed in the ratio of butyl benzoate (boiling point 250 degreeC) : toluene (boiling point 110 degreeC) = 2:8 as an 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 to be 2.0% by weight with respect to the entire composition 1.

[Formula 1]

(composition 2)

In the ink composition 2, a functional high molecular compound having a repeating structure of the above formula P1 as a functional material, a charge transport material, and 4-isopropyl-4'-methyldiphenyliodonium tetrakis (pentafluorocarbon) as an electron-accepting compound. A mixture of lophenyl)borate in a ratio of 5:1 is used. In Composition 2, as an organic solvent, an organic solvent mixed with 2ethylhexyl benzoate (boiling point: 297°C): mesitylene (boiling point: 164.7°C) = 2:8 was used. Then, these functional materials (solutes) were dissolved in an organic solvent, and an organic solvent having a boiling point of 250°C or higher (here, 2ethylhexyl benzoate) was prepared to be 2.0% by weight with respect to the total composition 2.

(Composition 3)

In ink composition 3, a functional high molecular compound having a repeating structure of the above formula P1 as a functional material, a charge transport material, and 4-isopropyl-4'-methyldiphenyliodonium tetrakis (pentafluorocarbon) as an electron-accepting compound. A mixture of lophenyl)borate in a ratio of 5:1 is used. In addition, composition 3 uses the organic solvent mixed in the ratio of benzyl benzoate (boiling point 323 degreeC) : toluene (boiling point 110 degreeC) = 2:8 as an organic solvent. Then, these functional materials (solutes) were dissolved in an organic solvent, and an organic solvent having a boiling point of 250°C or higher (here, benzyl benzoate) was prepared to be 2.0% by weight with respect to the entire composition 3.

(composition 4)

In ink composition 4, a functional high molecular compound having a repeating structure of the above formula P1 as a functional material, a charge transport material, and 4-isopropyl-4'-methyldiphenyliodonium tetrakis (pentafluorocarbon) as an electron-accepting compound. A mixture of lophenyl)borate in a ratio of 5:1 is used. Composition 4 uses an organic solvent mixed in a ratio of benzyl benzoate (boiling point: 323°C):cyclohexylbenzene (boiling point: 238.9°C) = 2:8 as an organic solvent. Then, these functional materials (solutes) were dissolved in an organic solvent, and an organic solvent (here, benzyl benzoate) having a boiling point of 250°C or higher was prepared to be 2.0% by weight with respect to the total composition 4.

(Comparative Composition 1)

In Comparative Ink Composition 1, a functional high molecular compound having a repeating structure of the above formula (P1) as a functional material, a charge transport material, and 4-isopropyl-4'-methyldiphenyliodonium tetrakis (pentane) as an electron-accepting compound. A mixture of fluorophenyl)borate in a ratio of 5:1 is used. In Comparative Composition 1, an organic solvent mixed in a ratio of tetralin (boiling point: 207.5°C):toluene (boiling point: 110°C) = 2:8 is used as the organic solvent. Then, these functional materials (solutes) were dissolved in an organic solvent, and the high boiling point organic solvent (here, teratrin) was prepared to be 2.0% by weight with respect to the entirety of Comparative Composition 1.

(Comparative Composition 2)

In Comparative Ink Composition 2, a functional high molecular compound having a repeating structure of the above formula P1 as a functional material, a charge transporting material, and 4-isopropyl-4'-methyldiphenyliodonium tetrakis (pentane) as an electron-accepting compound. A mixture of fluorophenyl)borate in a ratio of 5:1 is used. In Comparative Composition 2, 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 is used. Then, these functional materials (solutes) were dissolved in an organic solvent, and the high boiling point organic solvent (here, cyclohexylbenzene) was prepared to be 2.0% by weight with respect to the entirety of Comparative Composition 2.

(Rating 1)

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

In evaluation 1, the measurement was performed in the following flow. Ink droplets of each composition are ejected onto the substrate (B1). After that, the ink droplet K is photographed at the respective time points of natural drying (10 minutes) and natural drying (30 minutes). 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. Values obtained as a result of this measurement are shown in Fig. 14B.

Fig. 14B shows the volume of the remaining droplet of ink derived from the diameter of the ink droplet K derived from the image of each composition and the rate of change thereof. From the results shown in FIG. 14B , the inks (compositions 1 to 3) containing 20% by weight or more of an organic solvent having a boiling point of 250° C. or higher relative to the total ink had a volume change rate after a predetermined time (here, 10 minutes) had elapsed. It was found that this was small and the liquid volume was stable. On the other hand, about the ink (Comparative composition 1) used as a comparative example, solidification occurred by natural drying for 10 minutes.

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

(Rating 2)

Next, evaluation 2 in this verification is demonstrated. After receiving the result of evaluation 1, the discharge amount of the ink discharge head 23 was adjusted, the ink was applied to a predetermined application area, dried under reduced pressure, and the film thickness of the dried film of the functional layer was measured. The base material (B2) used here is a polyimide-based photoresist used in Evaluation 1 on a glass substrate. After patterning to a film thickness of 2 μm, pixel width of 90 μm, and bank width of 10 μm, the bank surface is coated with a CVD method. Production was carried out by adjusting the liquid so that the contact angle was 50 degrees with anisole.

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

16 shows the measurement results of evaluation 2 in this verification. Regarding Comparative Composition 1, as shown in FIG. 14B , since the droplet diameter could not be measured in Evaluation 1, the discharge 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 film thickness measurement position is set within a range of 20 cm from end to end.

Referring to FIG. 16 , composition 1 to composition 3 having ink characteristics according to the present embodiment had little variation in film thickness of the formed functional layer, and were at a level suitable for production of display panel D. On the other hand, in Comparative Composition 2, it was confirmed that the discharge amount could not be adjusted well, and that a uniform film thickness could not be formed due to film thickness variation and lack of fluidity at the coating end due to drying.

(Rating 3)

Next, the following evaluation was performed. As the base material (B1) used in the measurement, a substrate on which a liquid-repellent film was formed by applying a liquid-repellent resist to a glass substrate was used. The contact angle of the ink of Composition 4 on this substrate (B1) was 61.5 degrees. Ink droplets of Composition 4 were ejected onto this base material (B1), and after 1 minute, 5 minutes, 10 minutes, 20 minutes, and 30 minutes in a state of natural drying, the ink droplets (K) take a picture Then, the diameter of the ink droplet K was derived from the photographed image. Further, after drying by heating to evaporate the organic solvent, photographing was performed in the same manner to derive the diameter of the droplet K. 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 determined whether or not the amount of ink is maintained at a constant rate with respect to the amount of ink ejected after a predetermined time has elapsed since the ink was ejected onto the base material B1. do. Fig. 17 shows the change in the diameter of the ink droplet K derived from the image of composition 4. From the results shown in FIG. 17 , even if a solvent having a boiling point of 250°C or higher is 20% by weight or more with respect to the total ink, and a solvent with a boiling point of 238.9°C or lower is used, the droplet diameter after 5 minutes has elapsed. It can be seen that the change rate of is small, and after that, the change rate of the droplet diameter is small and stable until 30 minutes after natural drying. After air drying for 30 minutes and heat drying to remove the organic solvent, the droplet K is smaller, indicating that the organic solvent having a boiling point of 250°C or higher is stably present after 30 minutes of natural drying.

As described above, an organic solvent having a boiling point of 250°C or higher does not evaporate and dry in a normal temperature environment, so the amount of change is almost negligible, and the droplet diameter can be measured without requiring a special device. In addition, by containing an organic solvent having a boiling point of 250 deg. C or higher, fluidity of the ink can be ensured in an organic EL display panel having a thermal image bank, and film thickness variation can be suppressed.

By using the ink according to the present invention, the discharge amount of the ink droplet can be derived in a short time without requiring the step of measuring the ink droplet that changes over time each time. Then, based on the derived discharge amount, the droplet discharge amount for each ink ejection head nozzle can be easily equalized. Therefore, it is possible to suppress a decrease in the production efficiency of the inkjet apparatus due to the measurement of the discharge amount of liquid droplets. In addition, in this embodiment, since large-scale equipment is not required for droplet observation, it also leads to a reduction in equipment cost.

In addition, by performing the ejection defect inspection using the measurement method according to the present embodiment, it is possible to detect nozzle ejection defects, such as droplet droplet droplets or flight deflection, for example.

In addition, in the present invention, only a very small amount of ink is required to measure the amount of ink droplets ejected from the ink ejection head, so functional materials such as expensive organic EL materials can be efficiently used without waste. In addition, the ink according to the present invention can also reduce application unevenness due to natural drying or the like at the time of formation of the pixel pattern on the substrate after adjusting the discharge amount.

<Other embodiments>

Further, in the present invention, a program or application for realizing the functions of one or more embodiments described above is supplied to a system or device using a network or a storage medium, and one of the programs or applications in the computer of the system or device It is also possible to implement processing in which the above processor reads out and executes a program.

Further, it may be realized by a circuit that realizes one or more functions (eg, Application Specific Integrated Circuit (ASIC) or Field Programmable Gate Array (FPGA)).

In this way, the present invention is not limited to the above-described embodiments, and the present invention is intended to be modified and applied by those skilled in the art based on combinations of each configuration of the embodiments, descriptions in the specification, and well-known techniques. and is included in the scope of claiming protection.

As mentioned above, although various embodiments were described referring drawings, it goes without saying that the present invention is not limited to these examples. If it is a person skilled in the art, it is clear that various examples of change or correction can be conceived within the scope described in the claims, and it is understood that they also naturally belong to the technical scope of the present invention. Further, within a range that does not deviate from the spirit of the invention, you may combine each component in the above embodiment arbitrarily.

In addition, this application is based on the Japanese patent application (Japanese Patent Application No. 2020-202834) for which it applied on December 7, 2020, The content is used as a reference in this application.

A method for measuring the discharge amount of ink, an apparatus for manufacturing an organic EL display panel, an ink, and an organic EL display panel manufactured using the ink according to the present invention are apparatuses such as television sets, personal computers, mobile phones, and display panels having It can be widely used for manufacturing display panels and the like in various electronic devices. In addition, it can be widely used in the manufacture of electronic devices including a step of forming a functional layer using an ink application step.

1: Inkjet device
10: X axis table
11: Y axis table
12: X axis guide rail
13: Y axis guide rail
20: carriage unit
21: carriage support
22: Carriage
23: ink ejection head
30: camera unit
31: camera
32: camera support
40: Stage
41: stage rotation mechanism
42: X axis slider
50: control device
100: Substrate
119: pixel electrode
120: hole injection layer
121: hole transport layer
122: bank
123: light emitting layer
124: electron transport layer
125: counter electrode
126: encapsulation layer
127: bonding layer
128: color filter layer
130: upper substrate
131: color filter substrate
201: nozzle ball
202: ink droplet
B: Base
B1: substrate (for measuring discharge amount)
B2: substrate (for pattern formation)
K: ink droplet

Claims (22)

A measurement adjustment method comprising at least a measurement method of measuring an ejection amount of ink from an ink ejection head,
The measurement method,
a discharge step of discharging ink from the ink discharge head onto a substrate;
an acquisition step of acquiring an image of the ink ejected on the substrate;
a derivation step of deriving an ejection amount of ink from the ink ejection head based on information obtained from the image;
wherein the amount of the ink ejected on the substrate maintains a constant ratio to the amount of ink ejected from the ink ejection head after a predetermined time elapses after being ejected from the ink ejection head. . According to claim 1,
Further having a drying step of drying the ink ejected on the substrate for the predetermined time period,
A measurement adjustment method characterized in that, after the drying step, the acquisition step is executed. According to claim 1 or 2,
The ink includes a solvent and a functional material,
The measurement adjustment method characterized in that the solvent contains an organic solvent having a boiling point of 250°C or higher. A measurement adjustment method comprising at least a measurement method of measuring an ejection amount of ink from an ink ejection head,
The measurement method,
a discharge step of discharging ink from the ink discharge head onto a substrate;
an acquisition step of acquiring an image of the ink ejected on the substrate;
a derivation step of deriving an ejection amount of ink from the ink ejection head based on information obtained from the image;
The ink includes a solvent and a functional material,
The measurement adjustment method characterized in that the solvent contains an organic solvent having a boiling point of 250°C or higher. According to claim 4,
Further having a drying step of drying the ink ejected on the substrate for a predetermined period of time,
A measurement adjustment method characterized in that, after the drying step, the acquisition step is executed. According to any one of claims 1 to 3 and 5,
The measurement adjustment method according to claim 1, wherein the predetermined time period is 5 minutes or more. According to any one of claims 1 to 6,
The ink includes a solvent and a functional material,
The measurement adjustment method characterized in that the solvent contains an organic solvent having a boiling point of 300°C or higher. According to any one of claims 3 to 5 and 7,
The measurement adjustment method characterized in that the organic solvent is contained in an amount of 20% by weight or more with respect to the ink. According to any one of claims 1 to 8,
The measurement adjustment method characterized in that the substrate is coated with a liquid repellent coating material having liquid repellency to the ink. According to any one of claims 1 to 9,
The derivation process,
extracting the diameter of the ink droplet from the image;
derive the volume of ink on the substrate using at least the extracted diameter;
A measurement adjustment method characterized in that an ejection amount of ink from the ink ejection head is derived from the derived volume of ink on the substrate. According to any one of claims 1 to 10,
and an adjusting step of adjusting the ejection amount from the ink ejection head based on the ejection amount of ink derived by the derivation step. According to claim 11,
The measurement and adjustment method is used when forming at least one of a light emitting layer, a hole injection layer, and a hole transport layer among functional layers constituting an organic EL display panel. An ink discharge amount measurement and adjustment device for an ink discharge head, using the measurement and adjustment method according to any one of claims 1 to 12. A panel manufacturing system for an organic EL display panel having the ink ejection amount measuring and adjusting device according to claim 13. A method for manufacturing an organic EL display panel using the measurement adjustment method according to any one of claims 1 to 12. A method for manufacturing an organic EL display panel using the panel manufacturing system according to claim 14. An ink used in the measurement adjustment method according to any one of claims 1 to 12,
A solvent and a functional material corresponding to the functional layer,
Ink characterized in that the solvent contains an organic solvent having a boiling point of 250 ° C. or higher. An ink used in the ink ejection amount measuring and adjusting device according to claim 13,
A solvent and a functional material corresponding to the functional layer,
Ink characterized in that the solvent contains an organic solvent having a boiling point of 250 ° C. or higher. An ink used in the panel manufacturing system of the organic EL display panel according to claim 14,
A solvent and a functional material corresponding to the functional layer,
Ink characterized in that the solvent contains an organic solvent having a boiling point of 250 ° C. or higher. According to any one of claims 17 to 19,
The ink characterized in that the organic solvent is contained at 20% by weight or more with respect to the ink. According to any one of claims 17 to 20,
The ink, after being dried for a predetermined period of time, maintains an amount at a constant ratio with respect to the volume before the drying is carried out. An organic EL display panel on which a functional layer is formed using the ink according to any one of claims 17 to 21.