CN117063036A

CN117063036A - Film drying device

Info

Publication number: CN117063036A
Application number: CN202180096248.0A
Authority: CN
Inventors: 郑佐鎭; 崔溶元
Original assignee: Narae Nanotech Co ltd
Current assignee: Narae Nanotech Co ltd
Priority date: 2021-03-25
Filing date: 2021-10-15
Publication date: 2023-11-14
Also published as: KR102402737B1; WO2022203143A1; JP2024511781A

Abstract

The film drying device according to the present application is characterized by comprising: a broadband light source unit that irradiates a coating liquid applied to a substrate with light having a plurality of wavelengths in a broadband wavelength band, and dries the surface and the interior of the coating liquid at the same time; a light source driving part connected with the broadband light source and driving the broadband light source; and a control unit that controls an operation of the light source driving unit, wherein the broadband light source irradiates light having a plurality of wavelengths between an ultraviolet band and a near infrared band onto the substrate.

Description

Film drying device

Technical Field

The present application relates to a film drying device.

More particularly, the present application relates to a thin film drying apparatus capable of drying a coating liquid applied on a substrate from a surface to an inside in a short time as much as possible using a broadband light source.

Background

In general, in order to manufacture a flat panel display (Flat Panel Display; FPD) such as an electronic circuit device, an Organic Light Emitting Diode (OLED), or a liquid crystal display panel (LCD), a process of laminating various thin films is required. In particular, recently, an organic light emitting diode display is required to be flexible, and is used as a material such as a thin film-coated polyimide without using a glass substrate. In general, a flexible organic light emitting diode display is a display element formed after a thin polyimide layer is coated on a glass substrate. Then, the polyimide layer having the display element formed thereon was peeled off from the glass substrate, thereby manufacturing a display.

Recently, there is an increasing demand for improving the large area and flexibility of displays, and thus, more rapid and accurate formation of thin films is demanded.

Due to the technical requirements as described above, the organic light emitting diode display employs a process of coating polyimide on a glass substrate with a thinner thickness and curing. Since the polyimide film is formed in a state diluted in an organic solvent such as a solvent, a drying step is required, and conventionally, in order to dry a polyimide layer coated on a glass substrate, a hot air drying method in which air is heated by a heater and a fan provided in a drying furnace and supplied to the polyimide film to dry the polyimide film, or a method in which light is directly irradiated to the surface of the polyimide film by an infrared lamp is used.

However, the conventional hot air drying method using a heater and a fan or the process using an infrared lamp has the following problems.

In the conventional hot air drying method, the hot air is in contact with the surface of the liquid sensitizer, and the transferred heat is conducted from the surface of the sensitizer to the inside, so that the drying time is long, and thus the drying space required for moving the glass substrate coated with the polyimide film in the drying furnace is also long, and in the case of the in-line type drying furnace, there is a problem that a relatively wide space is required for manufacturing.

In addition, in the hot air drying method, dust and/or foreign matter may be contained in hot air during drying by supplying air heated by a heater by a fan, and in order to prevent inflow and/or removal of such dust and/or foreign matter, a purification facility needs to be provided, which has a problem of a lot of costs.

In order to solve the problem of the hot air drying method, a light drying method using a UV lamp and an IR lamp as a light source has been recently developed.

However, since the light drying system using the UV lamp and the light source of the IR lamp irradiates light of a specific wavelength band (for example, the UV lamp is light having an ultraviolet wavelength band, and the IR lamp is light having an infrared wavelength band), the irradiation amount of the light energy irradiated onto the polyimide film is considerably small, and there is a problem that the overall drying time from the surface to the inside of the polyimide film further increases.

Disclosure of Invention

Technical problem

The present application has been made to solve the above-described problems of the prior art, and an object of the present application is to provide a thin film drying apparatus capable of drying a coating liquid applied to a substrate by irradiating the coating liquid with light from an ultraviolet ray region to a near infrared ray region through a wide range by using a wide-band light source, thereby removing a solvent contained in the coating liquid in a short time.

Technical proposal

In order to achieve the above object, a film drying apparatus according to an embodiment of the present application includes: a broadband light source unit that irradiates a coating liquid applied to a substrate with light having a plurality of wavelengths in a broadband wavelength band, and dries the surface and the interior of the coating liquid at the same time; a light source driving part connected with the broadband light source and driving the broadband light source; and a control part controlling an operation of the light source driving part, the broadband light source irradiating light having a plurality of wavelengths between an Ultraviolet (UV) band to a near infrared (near infrared ray, NIR) band onto the substrate.

Effects of the application

With the film drying apparatus according to an embodiment of the present application, the following advantages are achieved.

1. With the use of a broadband light source capable of irradiating light having wavelengths in various wavelength bands from the ultraviolet region to the near infrared region, it is possible to remove a solvent contained in a coating liquid such as polyimide in a short time as much as possible, and further to dry the coating liquid.

2. The coating liquid can be dried significantly faster than in the prior art, and thus the drying space of the drying oven can also be minimized, thereby also greatly reducing the costs required for setting up the drying oven.

3. Since hot air is not used, there is no need for installation costs of a purification facility for preventing inflow of dust and/or foreign matter or for removing dust and/or foreign matter.

4. Due to the advantages of 1 to 3 described above, the manufacturing costs of the final product (e.g., organic light emitting diode display) are greatly reduced.

5. Due to the advantages of 1 to 3 described above, the film drying apparatus according to an embodiment of the present application for manufacturing a final product (e.g., an organic light emitting display) can be freely applied on an in-line type or batch type or the like.

Drawings

Fig. 1 is a view schematically showing the structure of a film drying apparatus according to an embodiment of the present application.

Fig. 2 is a graph showing the wavelength bands of light using ultraviolet and infrared light sources according to the related art.

Fig. 3 is a graph showing the graph of fig. 2 and the wavelength bands of light using the broadband light source 111 according to an embodiment of the present application.

Fig. 4 is a graph for explaining a comparison of a moving state of heat in a hot air drying manner according to the related art and an irradiation state of light using a broadband light source according to an embodiment of the present application.

Fig. 5 to 7 are diagrams schematically showing a structure in which a plurality of broadband light sources are arranged in a horizontal direction and/or a vertical direction with respect to a transfer direction of a substrate at an upper portion of the substrate according to an embodiment of the present application.

Fig. 8 is a diagram schematically showing a state in which a plurality of broadband light sources are connected in series or in parallel to one light source driving section according to an embodiment of the present application.

Fig. 9 is a diagram schematically showing an example of implementing a film drying apparatus according to an embodiment of the present application in-line.

Fig. 10 is a diagram schematically showing an example of a film drying apparatus according to an embodiment of the present application implemented by batch type.

Fig. 11 is a graph showing the results of experiments performed on the drying rate of the solvent in the coating liquid L applied on the substrate over time using the thin film drying apparatus according to an embodiment of the present application.

Detailed Description

Hereinafter, preferred embodiments according to the present application will be described in detail with reference to the accompanying drawings. It should be noted that in the drawings, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. A detailed description of known functions and configurations that can obscure the gist of the present application is omitted.

Referring to fig. 1, a film drying apparatus 100 according to an embodiment of the present application includes: a broadband light source unit 110 that includes a broadband light source 111, wherein the broadband light source 111 irradiates a coating liquid L applied on a substrate G with light having a plurality of wavelengths in a broadband wavelength band, and dries the surface and the interior of the coating liquid L at the same time; a light source driving unit 120 connected to the broadband light source 111 and driving the broadband light source 111; and a control part 130 controlling the operation of the light source driving part 120, the broadband light source 111 irradiating light having multiple wavelengths between Ultraviolet (UV) to near infrared (near infrared ray, NIR) wavelength bands onto the substrate G.

Hereinafter, the specific structure and operation of the film drying apparatus 100 according to an embodiment of the present application will be described in detail.

Referring again to fig. 1, the thin film drying device 100 according to an embodiment of the present application may include a broadband light source part 110, a light source driving part 120, and a control part 130.

The broadband light source part 110 according to an embodiment of the present application may include: a broadband light source 111 for irradiating a coating liquid L coated on the substrate G with light having a plurality of wavelengths in a broadband wavelength band to remove a solvent contained in the coating liquid L; and a housing 112 accommodating the broadband light source 111. In this case, the broadband light source part 110 according to an embodiment of the present application may include at least one broadband light source 111.

At this time, the wide frequency band of the light irradiated from the wide frequency light source 111 may be a band including a band from an ultraviolet band to a near infrared band.

More specifically, the wide frequency band of the wide frequency light source 111 may be, for example, a band in the range of 300nm to 1200 nm.

The broadband light source 111 according to an embodiment of the present application may include at least one inert gas of Xe, kr, ar, ne and He, and in an embodiment of the present application, a hernia lamp containing Xe gas may be used as the broadband light source 111, but it should be noted that it is not limited thereto.

Fig. 2 is a graph showing the wavelength bands of light using ultraviolet and infrared light sources according to the related art, and fig. 3 is a graph showing fig. 2 and the wavelength bands of light using the broadband light source 111 according to an embodiment of the present application.

Referring to fig. 2 (a), when a UV lamp is used as a light source for drying the coating liquid L, light having a wavelength of an ultraviolet band, i.e., a shorter band (300-600 nm), is irradiated onto the coating liquid L, and referring to fig. 2 (b), when an IR lamp is used, light having an infrared band, i.e., a longer band (800-1100 nm), is irradiated onto the coating liquid L.

That is, when a UV lamp is used as a light source in the film drying apparatus 100, since the light of a specific wavelength band (ultraviolet band of 300 to 600 nm) is irradiated onto the coating liquid L, the intensity of the light energy due to the short wavelength is large, but the total energy irradiation amount is small, and thus a long drying time is required to dry the coating liquid L from the surface to the inside.

In addition, when an IR lamp is used as a light source in the film drying apparatus 100, since light in a long infrared wavelength range of 800 to 1100nm is irradiated onto the coating liquid L, the intensity of light energy is weak, and particularly, a polyimide film used as the coating liquid L has a characteristic of low long wavelength transmittance, and thus has a problem of low drying performance and efficiency.

However, referring to fig. 3, when the broadband light source 111 according to an embodiment of the present application is utilized, light having multiple wavelengths including 300-1200nm of ultraviolet to near infrared bands is irradiated onto the coating liquid L, so that the total energy irradiation amount is increased compared to the light source of the related art illustrated in fig. 2, and in addition, the total energy intensity is increased, so that the surface and the inside of the coating liquid L can be simultaneously dried, and the drying time for drying the coating liquid L can be greatly shortened.

The graph illustrated in fig. 3 is a graph obtained when a voltage of 1000V is applied to a hernia lamp including Xe gas as a broadband light source.

Fig. 4 is a graph for comparing a moving state of heat in a hot air drying manner according to the related art with an irradiation state of light using the broadband light source 111 according to an embodiment of the present application.

Referring to fig. 4 (a), hot air of air heated by a heat source (heater: not shown) and a fan (not shown) according to the related art is supplied to a direction horizontal to the surface of the coating liquid L. Thus, the coating liquid L in contact with the hot air starts to dry from the surface, and therefore, the solvent existing inside the coating liquid L hardly comes out through the dried surface, and thus cannot be removed immediately, and the heat supplied to the surface of the coating liquid L by the hot air is transferred to the inside of the coating liquid L by conduction, and therefore, in order to remove the solvent inside the coating liquid L by heating, a considerable time is required, and finally, the drying time of the coating liquid L is remarkably prolonged.

However, referring to fig. 4 (b), when the broadband light source 111 according to an embodiment of the present application is utilized, not only light having a plurality of wavelengths including various ranges of wavelength bands (specifically, 300-1200nm ranges as shown in fig. 3) is irradiated from the broadband light source 111 to the surface of the coating liquid L, but also the irradiated light penetrates into the inside of the coating liquid L to be absorbed with sufficient energy, so that the surface and the inside of the coating liquid L can be simultaneously dried, and thus the drying time of the coating liquid L can be greatly shortened.

Referring to fig. 5 to 7, a plurality of broadband light sources 111 may be used according to an embodiment of the present application, and the plurality of broadband light sources 111 may be disposed at an upper side of the substrate G.

At this time, the plurality of broadband light sources 111 may be arranged in a direction perpendicular to the transfer direction of the substrate G at the upper portion of the substrate G (refer to fig. 5), or in a direction horizontal to the transfer direction of the substrate G at the upper portion of the substrate G (refer to fig. 6). The plurality of broadband light sources 111 may be arranged in a direction perpendicular to the transfer direction of the substrate G in a part of the upper portion of the substrate G, and in a direction horizontal to the transfer direction of the substrate G in the remaining part (see fig. 7). In the embodiment of fig. 7, the case where a part of the plurality of broadband light sources 111 is arranged in a direction perpendicular to the transfer direction of the substrate G is illustrated as an example, and the remaining part of the plurality of broadband light sources 111 is arranged in a direction horizontal to the transfer direction of the substrate G in turn, but it is well understood by those skilled in the art that the part of the plurality of broadband light sources 111 may be arranged in a direction horizontal to the transfer direction of the substrate G and the remaining part of the plurality of broadband light sources 111 is arranged in a direction perpendicular to the transfer direction of the substrate G in turn.

The light source driving part 120 according to an embodiment of the present application may be connected to the broadband light source 111 and drive the broadband light source 111.

Referring to fig. 8 (a) and 8 (b), in the thin film drying device 100 (refer to fig. 1) according to an embodiment of the present application, the plurality of broadband light sources 111 illustrated in fig. 5 to 7 may be connected with one light source driving part 120 in a parallel manner (refer to fig. 8 (a)) or in a serial manner (refer to fig. 8 (b)), so that one light source driving part 120 drives the plurality of broadband light sources 111.

Of course, one wide-band light source 111 may be connected to one light source driving unit 120 for driving, but in order to reduce the overall size of the thin film drying apparatus 100, it is preferable that a plurality of wide-band light sources 111 are connected to one light source driving unit 120 in parallel or in series for driving.

Referring to fig. 9, the thin film drying apparatus 100 (refer to fig. 1) according to an embodiment of the present application may be implemented, for example, by an In-Line Type (In-Line Type) manner of drying the coating liquid L coated on the substrate G while continuously transferring the substrate G.

At this time, the film drying apparatus 100 may include a conveyor belt 200 for continuously conveying the substrate G.

That is, in the film drying apparatus 100 realized by the in-line type illustrated in fig. 9, the plurality of substrates G coated with the coating liquid L are located on the conveyor belt 200 so as to be movable in the lower portion of the film drying apparatus 100. Thus, the continuous drying process of each coating liquid L applied on the plurality of substrates G can be performed by the broadband light source 111 provided in the thin film drying apparatus 100 (refer to fig. 1), so that not only the overall process time can be greatly shortened, but also the final product (for example, an organic light emitting diode display) can be mass-produced.

Referring to fig. 10, the thin film drying apparatus 100 (refer to fig. 1) according to an embodiment of the present application may be realized by Batch Type, i.e., a manner in which the broadband light source part 110 is provided in the sealed drying chamber 300, and the substrate G coated with the coating liquid L is put into the drying chamber 300 to be heated.

At this time, the drying chamber 300 in which the broadband light source section 110 of the film drying apparatus 100 is disposed may be provided with a dispensing port 301 for dispensing the substrate G and a discharge port 302 for discharging the dried substrate G. In this case, in order to dispense and discharge the substrate G through the dispensing port 301 and the discharge port 302 of the drying chamber 300, for example, a substrate pickup and transfer device (not shown) such as a robot arm for picking up and transferring the substrate G may be used.

A predetermined working space may be formed inside the drying chamber 300, which is a substantially hexahedral space, and may have a planar shape corresponding to the shape of the substrate G coated with the coating liquid L, but it should be noted that it is not limited thereto.

As shown in fig. 10, in the batch type thin film drying apparatus 100 (refer to fig. 1) according to an embodiment of the present application, a drying process is completed by discharging the dried substrate G after a drying process is performed by putting one substrate G into the drying chamber 300, and then putting a new substrate G into the drying chamber 300, and performing a drying process again.

Although not shown, it is well understood by those skilled in the art that the plurality of drying chambers 300 may be realized by a multi-stage drying chamber formed by a plurality of stages, and the drying process may be performed by supplying the plurality of substrates G to each of the multi-stage drying chambers, or by forming a plurality of separate drying spaces in one drying chamber 300, and then supplying the plurality of substrates G to each of the plurality of drying spaces after disposing the wide-band light source 110 of the film drying apparatus 100 shown in fig. 1 in each of the drying spaces.

Referring again to fig. 1, the control part 130 according to an embodiment of the present application may control the operation of the light source driving part 120, and as an example, the control part 130 may be implemented by a micro control unit (micro control unit, MCU).

The control unit 130 may control the light source driving unit 120 by using a pulse width modulation (pulse width modulation, PWM) method, thereby controlling the irradiation amount of light irradiated from the plurality of broadband light sources 111.

On the other hand, the control unit 130 may control the driving frequency to be in the range of 1 to 20Hz, the operating Time (On-Time) to be in the range of 300 to 1000 μs, the allowable current to be in the range of 100 to 1200A, and the discharge voltage to be in the range of 500 to 2000V for the plurality of broadband light sources 111.

The result of drying the coating liquid L using the broadband light source 111 according to an embodiment of the present application will be described in detail below.

Fig. 11 is a graph showing the results of experiments performed on the drying rate of the solvent in the coating liquid L applied on the substrate over time using the thin film drying apparatus 100 according to an embodiment of the present application.

Table 1 shows the drying rate of the solvent over time using the broadband light source 111 according to an embodiment of the present application.

[ Table 1 ]

The coating liquid L used in the coating liquid drying experiment using the film drying apparatus 100 according to an embodiment of the present application was Polyimide (PI) liquid, which was an AA-29B product manufactured by Keneka corporation. In this case, NMP (N-methyl-2-pyrrolidone; N-methyl-2-pyrolidone) was used as a solvent in the polyimide liquid, and the NMP content was 90% and the solid content was 10%. In addition, a polyimide liquid was applied to the substrate by bar coating (bar coating) at a thickness of approximately 50 to 55 μm in a wet state.

Then, the polyimide liquid (coating liquid L) applied to the substrate was dried for 30 seconds, 60 seconds, 90 seconds, and 120 seconds by the broadband light source 111, and the drying rate defined below was measured by an electronic scale.

At this time, the drying rate=the weight before the coating liquid L is dried/the weight after the coating liquid is dried.

As shown in table 1 and the graph of fig. 11, it was confirmed that after the coating liquid L was dried by the broadband light source 111, the NMP drying rate was substantially 90% or more for 90sec or more (the completely dried state in which NMP was completely removed). Further, it was confirmed that the coating thickness of the coating liquid L after drying was 5.4 μm or less at 90sec or more, and the coating thickness after drying was reduced by 90% or more from the initial coating thickness of the coating liquid L.

As is confirmed from the above results, when the conventional light source is used, a long drying time of at most 5 hours is required for completely drying the coating liquid L, but when the broadband light source 111 of the present application is used, the coating liquid L can be completely dried only by a drying time of approximately 90 seconds, and thus the drying time of the coating liquid L can be significantly shortened as compared with the conventional art.

As described above, according to the thin film drying apparatus of an embodiment of the present application, as a broadband light source capable of irradiating light having wavelengths of various bands from the ultraviolet region to the near infrared region is used, a solvent contained in a coating liquid such as polyimide is removed in a short time as much as possible, and thus the coating liquid can be dried.

In addition, when the thin film drying apparatus according to an embodiment of the present application is used, the coating liquid can be dried significantly more rapidly than in the related art, and thus the drying space of the drying oven can be minimized, thereby also greatly reducing the cost required for setting the drying oven.

In addition, unlike the related art, since hot air is not used, there is no need for installation costs of a purification facility for preventing inflow of dust and/or foreign matter or for removing dust and/or foreign matter.

In addition, the manufacturing costs of the final product (e.g., organic light emitting diode display) are greatly reduced due to the above advantages.

In addition, due to the above-described advantages, the film drying apparatus according to an embodiment of the present application can be freely applied to an in-line type or batch type (batch) type or the like.

Industrial applicability

As described above, although the present application has been described with reference to the drawings and the exemplary embodiments, the scope of the present application is not limited to the drawings and the exemplary embodiments, and may be arbitrarily modified and implemented in variation within the scope of the technical idea of the present application.

Claims

1. A film drying apparatus, comprising:

a broadband light source unit that includes a broadband light source that irradiates a coating liquid applied on a substrate with light having a plurality of wavelengths in a broadband wavelength band, and dries the surface and the interior of the coating liquid at the same time;

a light source driving part connected with the broadband light source and driving the broadband light source; and

a control part for controlling the operation of the light source driving part,

the broadband light source irradiates light with multiple wavelengths between ultraviolet wave bands and near infrared wave bands on the substrate.

2. The film drying apparatus according to claim 1, wherein,

the broadband band is a band in the range of 300nm to 1200 nm.

3. The film drying apparatus according to claim 1, wherein,

the broadband light source includes Xe, kr, ar, ne and at least one inert gas of He.

4. A film drying apparatus as claimed in claim 3, wherein,

as the broadband light source, a hernia lamp containing Xe gas was used.

5. The film drying apparatus according to claim 1, wherein,

the broadband light source is realized by a plurality of broadband light sources arranged on the upper part of the substrate, and is arranged in either one direction or both directions of a horizontal direction and a vertical direction relative to the conveying direction of the substrate.

6. The film drying apparatus according to claim 5, wherein,

the broadband light sources are connected with the light source driving part in parallel or in series.

7. The film drying apparatus according to any one of claims 1 to 6, wherein,

the broadband light source part further includes a housing accommodating the broadband light source.

8. The film drying apparatus according to any one of claims 1 to 6, wherein,

the control unit controls the light source driving unit by using a pulse width modulation method, thereby controlling the irradiation amount of light irradiated from the broadband light source.

9. The film drying apparatus according to claim 1, wherein,

the film drying apparatus further includes a conveyor belt continuously conveying the substrate.

10. The film drying apparatus according to claim 1, wherein,

the film drying apparatus further includes a sealed drying chamber provided with the broadband light source section,

the drying chamber is provided with a delivery port for delivering the substrate and a discharge port for discharging the dried substrate.

11. The film drying apparatus as claimed in claim 10, wherein,

the drying chamber is realized by a plurality of sections of drying chambers, the sections of drying chambers are formed by a plurality of sections of drying chambers,

a plurality of substrates (G) are respectively put into each of the multi-stage drying chambers, and a drying process is performed.

12. The film drying apparatus as claimed in claim 10, wherein,

the drying chamber forms a plurality of separated drying spaces inside, and the broadband light source part is arranged in each drying space,

and (3) putting the substrate into each of the plurality of drying spaces, so as to perform a drying process.