JP2023009015A - Dryer - Google Patents

Abstract

To provide a dryer capable of forming a uniform layer.SOLUTION: The dryer according to an embodiment of the present invention, comprises a chamber, a stage disposed in the chamber, a pair of supports each penetrating the stage, and a substrate disposed on the supports. The stage is heated during a drying step, and the substrate and the stage are separated from each other during the drying step. The upper part of the substrate is coated with a substance layer. The substance layer is coated by an inkjet method. The substance layer is an organic layer.SELECTED DRAWING: Figure 1

Description

The present disclosure relates to drying equipment.

The solution-based printing method enables large-area patterning directly without complicated processes such as vacuum and etching required by existing methods. Therefore, the solution-based printing method is widely used to form organic layers of light-emitting elements of displays including color filters or light-emitting elements of liquid crystal displays. The solution-based printing method forms an organic layer by ejecting an ink, which is a solution in which an organic substance is dissolved, to a desired position. Solvents in the ejected ink are dried to form an organic layer.

The light-emitting device is a self-light-emitting device and is excellent in power consumption, response speed, viewing angle and contrast ratio. A light-emitting device is composed of electrodes and organic layers including a light-emitting layer that generates excitons to emit light. The organic layers of the light emitting device can be formed by a solution-based printing method. However, when the organic layer is formed by the solution-based printing method, the thickness of the organic layer is not uniform and the surface is concave or convex. Such a concave or convex surface causes light emission with non-uniform luminance in the light-emitting region of the pixel, shortens the life of the device, and degrades the reliability of the device.

An object of one embodiment of the present invention is to provide a drying apparatus capable of forming a uniform layer.

The drying apparatus according to the present embodiment comprises a chamber, a stage located in the chamber and heated during the drying process, a support penetrating the stage, and located on the support and performing the drying process. The stage is heated during the drying process, and the substrate and the stage are separated during the drying process.

A material layer may be coated on the substrate.

The material layer may be applied by an inkjet method.

The material layer may be an organic layer.

The material layer may be one or more layers among a plurality of layers constituting a light emitting device.

A separation distance between the substrate and the stage may be 2 mm to 150 mm.

A separation distance between the substrate and the chamber may be 2 mm to 150 mm.

A ratio of a separation distance between the substrate and the stage and a separation distance between the substrate and the chamber may be 1:75 or more and 1:1 or less.

During the drying process, a separation distance between the substrate and the chamber may be greater than a separation distance between the substrate and the stage.

The substrate and the stage may be separated from each other while the stage descends during the drying process.

The substrate and the stage may be separated from each other while the support is raised during the drying process.

The stage and the substrate may not be in direct contact during the drying process.

A drying gas generated during the drying process may be capable of forming flows in upper and lower regions of the substrate.

The chamber may further include an exhaust port through which the dry gas is discharged.

A top plate positioned between the top of the substrate and the chamber may be further included.

The top plate may be heated during the drying step.

The top plate may not be in direct contact with the substrate.

According to this embodiment, it is possible to provide a drying apparatus capable of forming a uniform layer.

1 shows a simplified structure of a drying apparatus according to this embodiment. 4 is a schematic diagram of a structure in which a material layer is dried in a drying apparatus according to an embodiment; It shows a drying apparatus in which the substrate and the stage are in direct contact. 4 shows a structure in which a material layer is dried in the drying apparatus of FIG. 3; It shows the evaporation principle when the substrate and the stage are in direct contact. 6 shows the flow within the material layer during the drying process of the embodiment of FIG. 5; 6 shows the shape of the material layer before and after evaporation of the embodiment of FIG. 5; It shows the evaporation principle when the substrate and the stage are not in direct contact. 9 shows the flow in the material layer during the drying process in the embodiment of FIG. 8; 9 shows the shape of the material layer before and after evaporation in the embodiment of FIG. 8; The material layers are dried under different pressures and temperatures, and the profiles of the dried material layers are shown. It shows the profile of the material layer after drying with a drying device in which the substrate and the stage are in direct contact. 13 is a 2D profile of a material layer having the profile of FIG. 12; 13 illustrates a light emitting device including a material layer having the profile of FIG. 12; It shows the profile of the material layer after drying with a drying apparatus in which the substrate and the stage do not come into direct contact with each other. 16 is a 2D profile of a material layer having the profile of FIG. 15; 16 illustrates a light emitting device including a material layer having the profile of FIG. 15; Efficiency of the display device having the profile of FIG. 12 and the display device having the profile of FIG. 13 are measured according to color coordinates. Fig. 3 shows a drying apparatus according to another embodiment;

Hereinafter, various embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily implement the present invention. This invention is capable of application in many different forms and is not limited to the embodiments described herein.

In order to clearly describe the present invention, for example, descriptions of known techniques in the technical field to which the present invention belongs may be omitted, and the same or similar configurations and components are denoted by the same reference numerals throughout the specification. is added.

In addition, the size and thickness of each configuration and component shown in the drawings are shown in an arbitrary size and thickness for convenience of explanation, and the size and thickness of each configuration and component of the present invention are , are not necessarily limited to those indicated. Also, in the drawings, the thicknesses of various layers and regions, for example, are enlarged for clarity of representation of various layers and regions. Furthermore, in the drawings, the thickness of some layers and some regions are exaggerated for convenience of explanation.

Also, when a part such as a layer, film, region, plate, etc. is said to be "on" or "above" another part, it means not only being "directly on" another part, but also being in between. , and also when there are other parts in between. When a part is said to be "directly on" another part, it means that there is no other part in between. Also, to be "above" or "below" a reference portion means to be above or below the reference portion, and not necessarily "above" or "below" the side opposite to the direction of gravity. It is not meant to be “located on”.

In addition, throughout the specification, when a part "includes" a component, it does not exclude other components, unless otherwise specified. means.

In addition, throughout the specification, the term “on a plane” means that the target portion is viewed from above, and the term “cross section” refers to a cross section obtained by cutting the target portion vertically and viewed from the side. means time.

Hereinafter, a drying apparatus according to this embodiment will be described with reference to the drawings.

FIG. 1 schematically shows the structure of the drying apparatus according to this embodiment. Referring to FIG. 1, the drying apparatus according to the present embodiment includes a chamber 1000, a stage 100 positioned within the chamber 1000, a supporter 200 positioned through the stage 100 and vertically moving, and a substrate positioned on the supporter 200. 300 included.

Chamber 1000 can include a first chamber 1100 and a second chamber 1200 that are separated from each other. In the chamber 1000, the substrate 300 can be placed in the chamber 1000 while the first chamber 1100 and the second chamber 1200 are separated. The chamber 1000 shown in FIG. 1 has a configuration in which the first chamber 1100 and the second chamber 1200 are separated, but in the subsequent drying process, the first chamber 1100 and the second chamber 1200 are combined and sealed. can be a state. An exhaust port 1300 can be disposed at the bottom of the chamber 1000 . Steam generated during the drying process can be discharged through the exhaust port 1300 .

The stage 100 can be heated during the drying process. A material layer (not shown) on the substrate 300 can be dried by the heated stage 100 . The material layer may be an emissive layer material applied on the substrate 300 by an inkjet process or the like. Substrate 300 can be glass, but is not limited to glass only.

As shown in FIG. 1, in the drying apparatus according to this embodiment, the substrate 300 and the stage 100 are separated. The substrate 300 and the stage 100 do not come into direct contact with each other due to the supporting portion 200 protruding above the stage 100 .

This process is performed by positioning the substrate 300 on the stage 100 and then lifting the supporter 200 . Alternatively, such a process may be performed by placing the substrate 300 on the stage 100 and then lowering the stage 100 .

As described above, the substrate 300 and the stage 100 are not in direct contact with each other, and a space is formed between the substrate 300 and the stage 100. During the drying process of the material coated on the substrate 300, the drying gas is applied to the upper portion of the substrate 300. and can flow to the bottom. Therefore, the drying gas flow space is expanded to facilitate drying.

In this embodiment, the distance D1 between the substrate 300 and the stage 100 may be 2 mm or more and 150 mm or less. When the substrate 300 and the stage 100 are separated from each other without being in direct contact with each other, the above effects can be obtained. Therefore, the distance between substrate 300 and stage 100 may be 2 mm or more. If the distance between the substrate 300 and the stage 100 exceeds 150 mm, the material layer on the substrate 300 may not dry well due to the excessive distance.

Also, the distance D2 between the top of the substrate 300 and the chamber 1000 may be 2 mm or more and 150 mm or less. If the distance D2 between the substrate 300 and the chamber 1000 is 2 mm or less, the space for the drying gas to flow may not be sufficient, and drying may not be performed well. In this case, drying may be delayed because the inside of the chamber 1000 is not sufficiently heated.

In this embodiment, the distance D1 between the substrate 300 and the stage 100 and the distance D2 between the substrate 300 and the chamber 1000 may be the same or different. For example, the ratio of the distance D1 between the substrate 300 and the stage 100 and the distance D2 between the substrate 300 and the chamber 1000 may be 1:75 or more and 1:1 or less.

In this embodiment, the distance D2 between the substrate 300 and the chamber may be larger than the distance D1 between the substrate 300 and the stage 100. FIG. In this embodiment, since the material layer to be dried is positioned above the substrate 300, it is preferable that the space above the substrate 300 is large for effective drying.

The optimum separation distance may vary depending on the size of the substrate 300. FIG. That is, when the size of the substrate 300 is large, the amount of evaporation is large, so the optimum separation distance may be large. The separation distance can be appropriately adjusted according to the size of the substrate 300. FIG.

Even if the size of the substrate 300 changes, it is preferable that the distance D2 between the substrate 300 and the chamber is greater than the distance D1 between the substrate 300 and the stage 100 . By separating the substrate 300 and the stage 100 without making direct contact with each other, a similar effect can be obtained regardless of the separation distance.

Substrate 300 may be coated with a material forming a light emitting layer. For example, a light-emitting layer material may be coated on the substrate 300 . At this time, the emissive layer material can be applied by an inkjet method. Barrier ribs are placed on the substrate 300, and a light emitting layer material can be applied to spaces between the barrier ribs using an inkjet method. Materials on the substrate 300 can be dried by heating the stage 100 . In the present embodiment, a layer applied by, for example, an inkjet method and located on the substrate 300 is referred to as a material layer. The material layer can be a layer that constitutes a light emitting device, such as an electron injection layer, an electron transport layer, a light emitting layer, a hole transport layer, or a hole injection layer, but is not limited to the layers shown here. . Also, the material layer can be an organic layer, but is not limited to only an organic layer.

As shown in FIG. 1, in the drying apparatus according to the present embodiment, the stage 100 and the substrate 300 do not directly contact each other, so the coffee ring effect can be suppressed during the drying process.

The coffee ring effect refers to the phenomenon that when a liquid containing fine particles evaporates, the particles accumulate at the edges. The liquid has the characteristic of evaporating from the edge, and the liquid present on the inside moves towards the evaporating and vacant edge, trying to maintain its original form as much as possible. At this time, when particles are contained in the liquid, the particles are extruded together with the liquid and accumulated at the edges, which is called the coffee ring effect.

The effect of the drying apparatus according to this embodiment will be described below.

FIG. 2 schematically shows a structure for drying the material layer 400 in the drying apparatus according to the present embodiment. Referring to FIG. 2 , barrier ribs 350 are positioned on a substrate 300 , and a material layer 400 coated by an inkjet method may be disposed between the barrier ribs 350 . The material layer 400 can be an emissive layer, but is not limited to an emissive layer.

As shown in FIGS. 1 and 2, in the drying apparatus according to the present embodiment, the substrate 300 and the stage 100 are not in direct contact, so the material layer 400 can be uniformly vaporized over the entire substrate 300. FIG. Heat is not directly transferred from the stage 100 to the substrate 300, but the stage 100 heats the air in the chamber 1000 and the heat is evenly transferred to the substrate 300 by the dry air.

Unlike the present embodiment, when the substrate 300 and the stage 100 are in direct contact with each other, flow is formed from the center to the edge of the material layer 400, ie, the side adjacent to the barrier ribs 350 due to the coffee ring effect. In this case, the material layer 400 is dried into a U-shaped profile by such flow. Thus, if the material layer 400 is dried into a U-shaped profile, the display quality of the display device may be degraded. That is, when the material layer 400 is a light-emitting layer, the light-emitting layer is formed to have a U-shaped profile due to the difference in the drying speed of each region of the material layer 400 and the resulting flow. In this case, since the thickness of the light-emitting layer is different for each region of the material layer 400, the light-emitting efficiency of the light-emitting device may be reduced and the display quality of the display device may be degraded.

However, referring to FIGS. 1 and 2, in the drying apparatus according to the present embodiment, since the substrate 300 and the stage 100 are not in direct contact, the coffee ring effect can be suppressed. As shown in FIG. 2, in the drying apparatus according to the present embodiment, the material layer 400 is dried by the dry gas in the chamber 1000, so the amount of evaporation (evaporation amount) of the material layer 400 is determined for each region of the material layer 400. can be done similarly. In FIG. 2, the direction in which the material layer 400 evaporates is indicated by an arrow, and as shown in FIG. 2, it can be confirmed that the material layer 400 evaporates uniformly over almost all regions.

FIG. 3 shows a drying apparatus in which the substrate 300 and the stage 100 are in direct contact. Referring to FIG. 3, substrate 300 and stage 100 are in direct contact. Therefore, the heat of the stage 100 is directly transferred to the substrate 300 when the stage 100 is heated.

FIG. 4 is a diagram showing a structure in which the material layer 400 is dried in the drying apparatus of FIG. Referring to FIG. 4 , barrier ribs 350 are positioned on the substrate 300 and a material layer 400 can be disposed between the barrier ribs 350 . Material layer 400 may be an emissive layer.

Since the substrate 300 and the stage 100 are in direct contact, the heat of the stage 100 is directly transferred to the substrate 300 . Therefore, due to the coffee ring effect, the material layer 400 evaporates more actively at the edge of the material layer 400 and evaporates less at the center of the material layer 400 . In FIG. 4, the direction in which the material layer 400 evaporates is indicated by an arrow, and it can be seen that the material layer 400 evaporates differently in each region.

Thus, a flow is formed in the material layer 400 from the center toward the edge due to the difference in evaporation rate (eg, the difference in the amount of evaporation from region to region).

5 to 7 are diagrams schematically showing the principle of evaporation when substrate 300 and stage 100 are in direct contact. Referring to FIG. 5, substrate 300 and stage 100 are in direct contact and stage 100 is heated. A partition wall 350 is positioned on the substrate 300 and a material layer 400 is positioned between the partition walls 350 .

FIG. 6 is a diagram schematically showing the flow within the substance layer 400 during the drying process. Referring to FIG. 6, flow is formed in the material layer 400 in the direction of the arrow. Evaporation occurs relatively less in the central portion of the material layer 400 and occurs more frequently in the edges of the material layer 400 . Therefore, the material layer 400 in the central portion, which is less evaporated, forms a flow in such a direction from the center toward the edge.

FIG. 7 is a diagram schematically showing the shape of the material layer 400 before and after evaporation. As shown in FIG. 7, the flow of the material layer 400 from the center toward the edge increases the thickness of the material layer 400 at the edge.

8 to 10 are diagrams showing the principle of evaporation when substrate 300 and stage 100 are not in direct contact. Referring to FIG. 8, the material layer 400 is positioned between the barrier ribs 350 on the substrate 300, and the material layer 400 is evaporated by heated air (dry air).

FIG. 9 is a diagram schematically showing the flow within the material layer 400 during the drying process. Referring to FIG. 9, when the substrate 300 is not directly heated, the central portion of the material layer 400 evaporates relatively frequently, and the edge of the material layer 400 evaporates relatively less. In FIG. 9 the relative magnitude of evaporation is indicated by arrows. Evaporation actively occurs in the central portion of the material layer 400, as shown in FIG.

Therefore, the edge material layer 400 moves to the central portion of the material layer 400 where evaporation occurs actively, and a flow is formed in the direction from the edge to the center of the material layer 400 .

FIG. 10 is a diagram schematically showing the shape of the material layer 400 before and after evaporation. As shown in FIG. 10, the thickness of the material layer 400 is made uniform by the flow in the direction from the edges toward the center.

That is, when the substrate 300 and the stage 100 do not come into direct contact with each other as in the drying apparatus according to the present embodiment, the material layer 400 is dried from the center and flows from the edge toward the center. , the coffee ring effect is suppressed and a uniform profile can be formed.

FIG. 11 shows the profile (x-profile, height, width) of the material layer after drying the material layer 400 with different pressures and temperatures in a drying device in which the substrate and the stage are in direct contact. . The temperature rises in the order of A°C<B°C<C°C, and there is a temperature difference of 10°C or more in each zone.

Referring to FIG. 11, the substrate 300 and the stage 100 are directly connected to the substrate 300 even if the temperature and pressure are different under various conditions (temperatures A° C., B° C., and C° C.; pressures 1 torr, 0.1 torr, and 10 torr). When in contact, it can be seen that the profile of the material layer 400 has a U-shape. Adjustments in pressure and temperature change the shape of the profile, but as shown in FIG. 11, the overall profile is U-shaped even at different pressures and temperatures. This is because, as described above, when the substrate 300 and the stage 100 are in direct contact with each other, the flow is formed from the center to the edge of the material layer due to the coffee ring effect, and the thickness of the edge is increased.

Thus, if the profile of the material layer 400 is U-shaped, efficiency is reduced. For example, if the material layer 400 is a light emitting layer of a display device, the non-uniform thickness of the light emitting layer may reduce the light emitting efficiency.

However, when the material layer 400 is dried by a method in which the substrate 300 and the stage 100 do not come into direct contact with each other as in the present embodiment, the coffee ring effect during the drying process is suppressed and a uniform profile can be formed.

FIG. 12 shows a profile of a material layer after being dried in a drying apparatus in which the substrate 300 and the stage 100 are in direct contact with each other. Referring to FIG. 12, when the substrate 300 and the stage 100 are in direct contact, a U-shaped profile is formed due to the coffee ring effect.

13 is a 2D profile of the material layer having the profile of FIG. 12, and FIG. 14 is a diagram showing a device including the material layer having the profile of FIG. Referring to FIG. 13, it can be seen that the thickness of the material layer varies according to regions. It can be seen that the display quality of the display element is not uniform.

FIG. 15 is a diagram illustrating a profile of a material layer after being dried in a drying apparatus in which the substrate 300 and the stage 100 are not in direct contact according to the present embodiment. Referring to FIG. 15, it can be seen that when the substrate 300 and the stage 100 are not in direct contact, a flat profile is formed instead of a U-shaped profile.

16 is a 2D profile of the material layer having the profile of FIG. 15, and FIG. 17 is a diagram showing a device including the material layer having the profile of FIG. Referring to FIG. 16, it can be seen that the thickness of the material layer is relatively uniform in each region compared to FIG. Also, referring to FIG. 17, it can be seen that the overall brightness of the light emitting device is uniform compared to FIG.

FIG. 18 is a graph of luminous efficiency (Cd/A) measured by color coordinates (CIEx) for the display device having the profile of FIG. 12 (▴) and the display device having the profile of FIG. 15 (●). Referring to FIG. 18, it can be seen that the display device having the profile of FIG. 15 has excellent luminous efficiency.

FIG. 19 is a diagram showing a drying device according to another embodiment. Referring to FIG. 19, a drying apparatus according to another embodiment is similar to the drying apparatus shown in FIG. 1 except that it further includes an upper plate 500. FIG. A detailed description of components similar or similar to those in FIG. 1 is omitted here.

Referring to FIG. 19, the stage 100 located below the substrate 300 and the upper plate 500 located above the substrate 300 are all dried. That is, the stage 100 and the upper plate 500 are all heated, and the substrate 300 is dried both above and below. Therefore, compared to the embodiment shown in FIG. 1, the drying speed of the substrate 300 can be increased.

As described above, the drying apparatus according to an embodiment of the present invention prevents direct contact between the substrate 300 and the stage 100, suppresses the coffee ring effect during the drying process, and forms a flat profile shape. to Therefore, in the drying apparatus according to the embodiment of the present invention, when the light-emitting layer is formed on the substrate 300, the profile of the light-emitting layer becomes flat, thereby improving luminous efficiency and display quality.

As described above, one embodiment of the present invention has been described in detail. Various modifications and improvements made by those skilled in the art also belong to the scope of the present invention.

1000: Chamber 100: Stage 200: Support 300: Substrate 500: Top plate

Claims (17)

a chamber;
a stage located within the chamber and heated during the drying process;
a support penetrating through the stage;
a substrate positioned on the support and separated from the stage during the drying process;
including,
drying equipment. 2. The drying apparatus of claim 1, wherein a material layer is coated on the substrate. 3. The drying apparatus of claim 2, wherein the material layer is applied by an inkjet method. 3. The drying apparatus of claim 2, wherein said material layer is an organic layer. 3. The drying apparatus of claim 2, wherein the material layer is one or more layers among a plurality of layers forming a light emitting device. 2. The drying apparatus according to claim 1, wherein the separation distance between said substrate and said stage is 2 mm to 150 mm. The drying apparatus according to claim 1, wherein the separation distance between said substrate and said chamber is 2 mm to 150 mm. 2. The drying apparatus according to claim 1, wherein the ratio of the separation distance between said substrate and said stage and the separation distance between said substrate and said chamber is 1:75 or more and 1:1 or less. 2. The drying apparatus of claim 1, wherein during the drying process, the separation distance between the substrate and the chamber is greater than the separation distance between the substrate and the stage. 2. The drying apparatus of claim 1, wherein the substrate and the stage are separated from each other while the stage descends during the drying process. 2. The drying apparatus according to claim 1, wherein the substrate and the stage are separated from each other while the supporting part is raised during the drying process. 2. The drying apparatus according to claim 1, wherein said stage and said substrate are not in direct contact during said drying process. 2. The drying apparatus of claim 1, wherein the drying gas generated during the drying process forms flows in upper and lower regions of the substrate. 14. The drying apparatus of claim 13, wherein the chamber further includes an exhaust port through which the drying gas is exhausted. 2. The drying apparatus of claim 1, further comprising a top plate positioned between the top of the substrate and the chamber. 16. Drying apparatus according to claim 15, wherein the top plate is heated during the drying step. 16. Drying apparatus according to claim 15, wherein the top plate does not directly contact the substrate.

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