JP2021039845A - Functional element, manufacturing method of the same, manufacturing device of the same, control program, and recording medium - Google Patents

Abstract

To reduce unevenness in the ink film thickness when drying ink by airflow.SOLUTION: A functional element in which a first bank 7a and a second bank 7b are formed on a substrate 6 includes a capacitance unit 30 consisting of the first bank 7a, the second bank 7b, and the substrate. In a cross-section of the capacitance unit 30 viewed from a predetermined direction, a first angle between the first bank 7a and the substrate and a second angle between the second bank 7b and the substrate are different.SELECTED DRAWING: Figure 5

Description

The present invention relates to a functional element and the manufacture of the functional element.

An organic EL element is an element in which a light emitting layer is formed of an organic low molecule or an organic polymer having EL light emitting ability, and has excellent features as a display element such as a wide viewing angle due to self-luminous emission and excellent impact resistance. Have.

As a method for manufacturing an organic EL element, a vacuum deposition method, an inkjet method, a printing method, a dispensing method and the like have been widely studied. Above all, the inkjet method is expected to be a technology suitable for mass production because the manufacturing apparatus can be downsized and the material utilization efficiency is excellent as compared with the vacuum vapor deposition method and the like. Generally, in order to manufacture an organic EL element, it is necessary to stack a large number of layers such as electrodes, light emitting layers, and intermediate layers, but in order to improve mass productivity, it is recommended to manufacture as many layers as possible by the inkjet method. It can be said that it is desirable.

For example, in the method for manufacturing an organic EL element described in Patent Document 1, in a drying step after applying an ink containing an organic EL light emitting element, an exhaust device is arranged at a position facing a horizontally arranged substrate and a volatile solvent is used. A method of sucking and exhausting the atmosphere has been proposed.

Japanese Unexamined Patent Publication No. 2014-199806

FIG. 9 is a diagram for explaining a problem that occurs in a manufacturing method having a drying step of blowing air as in Patent Document 1. FIG. 9A is a diagram when ink is applied to a capacitance portion composed of a bank and a base material, and FIG. 9B is a state in which an airflow is generated by an airflow generator and dried. From FIG. 9A, the film thickness of the ink is uniform before the air flow is generated. However, as shown in FIG. 9B, the amount of ink applied is very small, and when the airflow is blown onto the ink, the film thickness of the ink is uneven depending on the direction in which the airflow is blown. Then, since the ink dries with the bias occurring, there is a problem that the film thickness of the ink after drying is biased and the film thickness unevenness occurs in the light emitting layer.

In view of the above problems, in the present invention, a functional element in which a first bank and a second bank are formed on a substrate, the capacitance portion including the first bank, the second bank, and the substrate. The first angle formed by the first bank and the substrate and the second angle formed by the second bank and the substrate are formed in a cross section of the capacitance portion when viewed from a predetermined direction. We adopted a functional element that is different.

According to the present invention, when the ink is dried by the air flow, it is possible to reduce the unevenness of the ink film thickness.

It is a top view of the display device 100 in an embodiment. It is a schematic diagram of the manufacturing apparatus 1000 in an embodiment. It is a figure which showed the shape of the bank 7 in embodiment. It is sectional drawing of the bank 7 in embodiment. It is sectional drawing when ink 8 is applied to the capacity part 30 in embodiment. It is sectional drawing when the airflow 4 was blown from the state of FIG. It is a figure which showed the manufacturing of the functional element in an embodiment. It is a figure explaining a comparative example. It is a figure explaining the conventional problem.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the accompanying drawings. The embodiments shown below are merely examples, and the detailed configuration can be appropriately changed without departing from the spirit of the present invention. Further, the numerical values taken up in the present embodiment are reference numerical values and do not limit the present invention.

In the following description, a top emission type organic EL element will be mentioned as a functional element, and its structure and manufacturing method will be described. However, the embodiment of the present invention is not limited to this example, and other types of organic EL elements and other types of organic EL elements and It can be applied to functional elements other than organic EL elements and their manufacturing methods.

(First Embodiment)
FIG. 1 is a schematic plan view of a display device 100 according to the present embodiment, which includes a large number of organic EL elements as functional elements. FIG. 1 is an XY plan view seen from a certain direction of the XYZ coordinate system. In the following drawings, the arrows X, Y, and Z in the drawing indicate the coordinate system of the entire display device 100. A red light emitting organic EL element (R), a green light emitting organic EL element (G), and a blue light emitting organic EL element (B) are regularly arranged as display pixels 60 on the upper surface of the substrate 6. For convenience of illustration, only 7x9 RGB triplets are shown, but in practice a very large number of display pixels can be arranged on the substrate 6. Further, the emission color of the organic EL element is not limited to red, green, and blue, and the arrangement rule of each color is not limited to this example.

FIG. 2 is a schematic view showing a manufacturing apparatus 1000 for an organic EL element as a functional element in the present embodiment. The manufacturing apparatus 1000 includes an airflow generator 500 that blows out an airflow 4 that dries the liquid ink 8 ejected from an ink ejector (not shown). The ink 8 includes the light emitting organic EL element described above, and functions as a display pixel 60. The airflow generator 500 has an airflow supply head 2 provided with an airflow supply path 3 for supplying the airflow 4 and a supply port 20 for blowing out the airflow 4. Further, a moving means 1 for moving the airflow generator 500 in the direction of the arrow P is provided.

A plurality of banks 7 for isolating and holding the ink 8 containing each light emitting organic EL element are formed on the substrate 6, and in FIG. 2, the ink 8 is formed by each bank 7 and the substrate 6. It is assumed that it is held in the capacitance section.

From FIG. 2, the airflow 4 is supplied from an air tank (not shown) via the airflow supply path 3, and the center line C of the supply port 20 and the base 6 are supplied from the supply port 20 of the airflow supply head 2 toward the base 6. It is sprayed along the elevation angle 5 formed by the surface. The supply port 20 includes a drive unit that changes the angle of the center line C with respect to the substrate 6 so that the elevation angle 5 can be changed.

In the airflow supply path 3, a pipe is connected to the airflow supply head 2 via a joint. The airflow 4 is started and stopped by the on-off valve of the air tank, and the supply start and stop is controlled by the position or time of the airflow generator 500. By using a sequencer, a PC, or the like to start and stop the supply of the airflow and control the supply port 20, the airflow 4 can be blown to a predetermined position. In addition, by providing a flow rate adjusting valve (not shown) in the air tank, the supply amount can be adjusted.

The moving means 1 is composed of a guide mechanism, a drive mechanism, and a control device. A linear motion guide or an air slide is used for the guide mechanism. A combination of a ball screw and a motor or a linear motor is used as the drive mechanism. To control the position of the airflow generator 500, a method of monitoring the position by providing a sensor on the motor or a method of controlling the position using a sequencer is used. Further, since the motor is used as the drive mechanism, it is possible to control the moving speed of the airflow generator 500 to move at a constant speed or to shift or stop depending on the position.

In the present embodiment, the airflow generator 500 is configured to move in the direction of the arrow P, which is a direction parallel to the plane of the substrate 6. This is because when the substrate 6 is large, it is preferable to move the airflow generator 500. If the substrate 6 is small to some extent, the substrate 6 may be moved.

FIG. 3 is a diagram illustrating the shape of the bank 7 of the present embodiment. FIG. 3A is an XY plan view of the bank 7. FIG. 3B is a YZ plan view of the bank 7, and is a cross-sectional view when the line segment BB of FIG. 3A is cut in the −Z direction. FIG. 3C is an XZ plan view of the bank 7, and is a cross-sectional view of the line segment AA in FIG. 3A cut in the −Z direction. In FIG. 3B, the cross-sectional view of the bank 7 on the YZ plane has a rectangular shape. In FIG. 3C, the cross-sectional view of the bank 7 in the XZ plane has a trapezoidal shape.

FIG. 4 is a detailed cross-sectional view of the bank 7XZ plane. The angle α, which is the base angle in FIG. 4, is the angle on the upstream side of the airflow 4, in other words, the angle on the side close to the supply port 20 in FIG. Further, the angle β, which is the base angle, is the angle on the downstream side of the airflow 4, in other words, the angle on the side far from the supply port 20 in FIG. In the present embodiment, the bank 7 is formed so that the angle α has a shape larger than the angle β.

FIG. 5 is a detailed view of the capacitance section 30 for holding the ink 8 formed by each bank 7 and the substrate 6. In FIG. 5, for the sake of clarity, the side closer to the airflow generator 500 is referred to as bank 7a, and the side farther from the airflow generator 500 is referred to as bank 7b. Due to the shape of the bank 7 described with reference to FIG. 4, the angle β ′ formed by the bank 7a and the base 6 can be made larger than the angle α ′ formed by the bank 7b and the base 6 in the capacitance portion 30. As a result, the tension at the interface between the ink 8 and the bank 7a can be made larger than the tension at the interface between the ink 8 and the bank 7b.

Therefore, the ink 8 can be biased closer to the airflow generator 500, in other words, on the upstream side of the airflow 4. Of course, depending on the direction in which the airflow 4 is blown, a bias may be generated on either angle side. Let H be the bias of the ink 8.

FIG. 6 shows a state in which the airflow 4 is generated from the airflow generator 500 from the state of FIG. The elevation angle 5 is controlled by the supply port 20 so as to be larger than 90 degrees and smaller than 180 degrees. When the airflow 4 is blown out, the airflow 4 is first blown to the bias H. As a result, the bias H is flowed to the downstream side of the air flow 4 before the ink 8 dries, and the bias H is eliminated. As a result, the ink 8 can be dried by the air flow 4 without causing bias, and the uneven film thickness of the ink 8 after drying can be reduced.

FIG. 7 is a diagram showing a method of manufacturing a functional element according to the present embodiment. First, from FIG. 7A, the resist material 14 is applied to the glass substrate 13 as the substrate, which has been previously cleaned by removing dust and oxide film on the surface. As the resist material, commercially available SiO or PI whose viscosity was adjusted so that a film thickness of about several μm to 100 μm could be formed was used. A spin coater, a spray coater, or the like is used to apply the resist material. It is assumed that a connection electrode (not shown), a TFT, a plug, and an insulating layer (not shown) are formed between the glass substrate 13 and the resist material 14.

After applying the resist material 14, the patterns of the glass substrate 13 and the mask 16 are aligned from FIG. 7B, and the resist material 14 is irradiated with ultraviolet rays 15 to transfer the pattern of the mask 16. By irradiating the ultraviolet light 15, the mask 16 forms two regions, an exposed region 17 and a non-exposed region 18, in the resist material 14.

After the exposure, from FIG. 7C, the exposed region 17 is removed by development, and the bank 7 is formed by baking and thermal cross-linking to form the capacitance portion 30. For exposure, close contact exposure in which a mask is brought into close contact with a substrate, reduced projection step exposure by a lens optical system using an exposure apparatus, and 1x scan exposure by a mirror optical system are used. In this embodiment, close contact exposure was used, and the mask pattern was designed and exposed so that the bank 7 had the shape described in FIG. A plurality of masks may be prepared and defocused to expose the bank 7 so as to have a predetermined shape, or projection exposure may be used. Ultraviolet rays are used as the light source for exposure, and the wavelength thereof is determined by the photosensitive wavelength of the resist material 14.

After developing and baking, the ink 8 is dropped into a predetermined position by the ink coating head 19 from FIG. 7 (d). Further, in FIG. 7D, the control device 200 is a control unit that controls the operation of the ink coating head 19. The control device 200 is a computer for controlling the operation of the ink coating head 19, and includes a CPU, a ROM, a RAM, an I / O port, and the like inside.

The basic operation program of the ink coating head 19 is stored in the ROM. A program for executing various processes such as an ink applying operation for manufacturing a functional element can be stored in a ROM in the same manner as other operation programs. Alternatively, it may be loaded into the RAM from the outside via the network. Alternatively, the program may be loaded into RAM via a computer-readable recording medium on which the program was recorded.

The I / O port of the control device 200 is connected to an external device such as an external computer or a network. The control device 200 inputs / outputs data necessary for manufacturing the functional elements such as the type, position, arrangement, and ink ejection conditions of the functional elements to be manufactured to and from an external computer via the I / O port. It can be carried out.

The control device 200 is connected to an ink coating head 19, a main scanner (not shown), a sub-scanner, and the like, and can exchange electrical signals. The control device 200 controls the operation of each of these parts, and executes processing related to ink application in general, including scanning of the ink application head 19, ejection of ink from each nozzle of the ink application head 19, and the like.

Further, before dropping the ink 8, a liquid in which conductive fine particles such as Ag, Au, Cu, Al, and Ni are dispersed in a solvent is applied to the capacitance portion 30, and if necessary, the lower electrode is fired. Shall be formed.

To explain the ink ejected from the nozzle, for example, in the case of forming a light emitting layer, a fluorescent organic compound or a phosphorescent organic compound corresponding to a desired emission color is dissolved in an organic solvent such as xylene. An organic solvent-based ink that has been prepared can be used. The organic solvent-based ink for the light emitting layer may contain a plurality of materials such as a guest material and a host material. Examples of the light emitting material contained in the ink include a high molecular weight material, a medium molecular weight material, a low molecular weight material, and the like, and the light emitting material is not particularly limited as long as it can be used for a coating type. Examples thereof include polyfluorene, a copolymer of polyfluorene, a polymer material such as polyphenylene vinylene, and a medium molecular material such as oligofluorene.

Further, low molecular weight materials such as condensed polycyclic compounds such as fluorene type, pyrene type, fluoranthene type and anthracene type, and metal complexes containing iridium can also be mentioned. The light emitting layer may preferably contain a polymer-based material such as a polyparaphenylene vinylene derivative, a polythiophene derivative, a polyparaphenylene derivative, a polysilane derivative, a polyacetylene derivative, a polyfluorene derivative, and a polyvinylcarbazole derivative.

To form a red light emitting layer, for example, a red phosphorescent iridium metal complex is used as a guest material, and an ink for a red light emitting layer containing polyfluorene is used as a host material. Further, in order to form a green light emitting layer, for example, a fluoranthene-based condensed polycyclic compound is used as a guest material, and an ink for a green light emitting layer containing polyfluorene as a host material is used. Further, in order to form a blue light emitting layer, for example, a pyrene-based condensed polycyclic compound is used as a guest material, and an ink for a blue light emitting layer containing oligofluorene as a host material is used.

As described in FIG. 5, the ink 8 is applied to the capacitance portion in a state where the ink 8 is biased due to the shape of the bank.

Then, from FIG. 7E, the ink 8 is dried by the airflow 4 using the airflow generator 500. It is assumed that the airflow generator 500 is also connected to the control device 200 described above, and the airflow 4 is controlled by scanning and the supply port 20 using the moving means 1. The ink 8 application step and the air flow 4 drying step are repeated three times to apply three colors (RGB). Further, in the present embodiment, for example, when the red ink is applied to all the capacitance portions 30, the air flow 4 is blown, and then the blue ink, the green ink, and the like are applied and dried. However, the application and drying may be repeated in each of the capacity portions 30, such that the ink is instantly dried after being applied to one capacity portion 30 of each ink. As described above, the bias is flowed to the downstream side of the air flow 4 before the ink 8 dries, and the bias is eliminated. As a result, the ink 8 can be dried by the air flow 4 without causing bias, and a functional element in which the film thickness unevenness of the ink 8 is reduced can be manufactured.

(Example)
The functional element was actually manufactured by using the manufacturing method described with reference to FIG. 7. The details will be described below using specific numerical values. As the glass substrate 13 as the substrate 6, a G8.5 generation 2200 × 2400 mm glass substrate was used. As the resist material 14, a material containing carbon black as a pigment was used to form a bank 7 having a height of 2 to 5 μm, a bottom width of 10 μm, and a bank-to-bank distance of 100 μm. The exposure amount and wavelength of the ultraviolet light 15 differ depending on the resist material 14 used, but in this example, the exposure amount was 100 mJ / cm ² and the wavelength was 350 to 450 nm.

As the mask 16, the one determined by examining the optimum mask shape in advance so that the angle β'described in FIG. 5 is larger than the angle α'was used. Development was carried out for 100 seconds using a developing solution. The ink application head 19 used an inkjet of a method using a piezo element. Droplets are ejected from a nozzle that applies a drive voltage to the piezo element. Eighty nozzles of the ink application head 19 were arranged at intervals of about 320 μm.

As for the moving speed of the airflow generator 500, the moving speed was set and the flow rate of the airflow 4 was adjusted so that the relative speed with respect to the airflow 4 was 0.1 m / s. The movement speed was set by combining a commercially available sequencer and a servo controller.

As a result of observing the cross section of the ink-applied portion after drying, the ink wets the bank on the upstream side and becomes a thick film as shown in FIG. 5 before drying. The result was that the film thickness distribution was almost uniform.

(Comparison example)
As a comparative example, FIG. 8 is a diagram in which the elevation angle at the time of blowing the airflow is sprayed parallel to the plane of the substrate in the forming method described in the first embodiment.

As a result of observing the cross section of the ink-applied portion after drying, the ink wets the bank on the upstream side as shown in FIG. 5 and becomes a thick film before drying. However, the unevenness of the ink due to the blowing of the airflow is not well eliminated, and the film thickness becomes uneven when the airflow is blown. The result was that the film thickness distribution of the ink film thickness remained non-uniform.

Specifically, the processing procedure of the above-mentioned manufacturing method has been described as being executed by the control unit of the manufacturing apparatus. A software control program capable of executing the above-mentioned functions and a recording medium on which the program is recorded constitute the present invention. For example, as a recording medium for supplying the control program, an HDD, an external storage device, a recording disk, or the like may be used.

The present invention is not limited to the above-described embodiment, and many modifications can be made within the technical idea of the present invention. Moreover, the effects described in the embodiments of the present invention merely list the most preferable effects arising from the present invention, and the effects according to the present invention are not limited to those described in the embodiments of the present invention.

1 Transportation means 2 Airflow supply head 3 Airflow supply path 4 Airflow 5 Elevation angle 6 Base 7 Bank 7a 1st bank 7b 2nd bank 8 Ink 13 Glass substrate 14 Resist material 15 Ultraviolet rays 16 Mask 17 Exposed area 18 Non-exposed area 19 Ink coating head 20 Supply port 30 Capacity part 60 Display pixel 100 Display device 200 Control device 500 Airflow generator 1000 Manufacturing device

Claims (20)

A functional element in which a first bank and a second bank are formed on a substrate.
A capacitance portion including the first bank, the second bank, and the substrate is provided.
In the cross section of the capacitance portion viewed from a predetermined direction, the first angle formed by the first bank and the substrate and the second angle formed by the second bank and the substrate are different.
A functional element that is characteristic of this. In the functional element according to claim 1,
A light emitting material is applied to the capacitance portion.
The luminescent material is applied between the first bank and the second bank.
A functional element characterized by this. In the functional element according to claim 1 or 2.
The cross section of the first bank and the second bank when viewed from the predetermined direction is trapezoidal.
The size of the base angle of the cross section is different,
A functional element characterized by this. In the functional element according to claim 2 or 3,
The first angle is larger than the second angle,
When the light emitting material is applied to the capacitance portion in a liquid state, the light emitting material is biased toward the first angle side.
A functional element characterized by this. In the functional element according to any one of claims 1 to 4.
The predetermined direction is a direction parallel to the plane on which the first bank and the second bank are provided on the substrate.
A functional element characterized by this. In the functional element according to any one of claims 2 to 5,
The luminescent material is an organic compound.
A functional element characterized by this. A display device using the functional element according to any one of claims 1 to 6. A display using the functional element according to any one of claims 1 to 6. It is a manufacturing method of functional elements.
In the forming step of forming the first bank and the second bank on the substrate,
The first bank and the second bank are formed so that the first angle formed by the first bank and the base is different from the second angle formed by the second bank and the base.
A manufacturing method characterized by that. In the manufacturing method according to claim 9,
Further comprising an imparting step of imparting a light emitting material to a capacitance portion composed of the first bank, the second bank, and the substrate.
In the applying step, the luminescent material is applied between the first bank and the second bank.
A manufacturing method characterized by that. In the manufacturing method according to claim 9 or 10.
In the forming step, the first bank and the second bank have a trapezoidal shape when viewed from the predetermined direction, and the first bank and the second bank have different base angles of the cross sections. It is formed,
A manufacturing method characterized by that. In the manufacturing method according to claim 10 or 11.
In the forming step, the first bank and the second bank are formed so that the first angle is larger than the second angle.
In the applying step, when the luminescent material is applied to the capacitance portion in a liquid state, the luminescent material is biased on the first angle side.
A manufacturing method characterized by that. In the manufacturing method according to any one of claims 10 to 12,
Further provided with a drying step of generating an air flow by an air flow generator and drying the light emitting material by the air flow.
In the drying step,
Of the angles at which the airflow of the airflow generator is blown onto the substrate, the elevation angle is greater than 90 degrees and smaller than 180 degrees.
A manufacturing method characterized by that. In the manufacturing method according to claim 13,
The angle is controlled by the airflow supply port of the airflow generator.
A manufacturing method characterized by that. In the manufacturing method according to claim 13 or 14.
In the drying step, the airflow is blown over the entire substrate.
A manufacturing method characterized by that. In the manufacturing method according to claim 13 or 14.
In the drying step, the airflow is blown for each capacitance portion.
A manufacturing method characterized by that. In the manufacturing method according to claim 12,
Further provided with a drying step of generating an air flow by an air flow generator and drying the light emitting material by the air flow.
The manufacturing method is characterized in that, in the drying step, an air flow is blown from the side where the bias occurs. A manufacturing device that manufactures functional elements.
When forming the first bank and the second bank on the substrate
The first bank and the second bank are formed so that the first angle formed by the first bank and the base is different from the second angle formed by the second bank and the base.
A manufacturing device characterized by that. A control program capable of executing the manufacturing method according to any one of claims 9 to 17. A computer-readable recording medium on which the control program according to claim 19 is recorded.

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