KR102402737B1 - Apparatus for drying thin-film - Google Patents

Abstract

According to the present invention, a thin film drying device comprises: a broadband light source unit having a broadband light source for simultaneously drying a surface and the inside of a coating liquid by irradiating light having multiple wavelengths of a broadband wavelength band onto the coating liquid applied onto a substrate; a light source driving unit connected to the broadband light source and driving the broadband light source; and a control unit controlling an operation of the light source driving unit. The broadband light source irradiates light having multiple wavelengths between an ultra violet (UV) wavelength band and a near infrared ray (NIR) wavelength band onto the substrate.

Description

Thin film drying device {APPARATUS FOR DRYING THIN-FILM}

The present invention relates to a thin film drying apparatus.

More specifically, the present invention relates to a thin film drying apparatus capable of drying a coating liquid applied on a substrate from the surface to the inside in the shortest possible time using a broadband light source.

In general, in order to manufacture an electronic circuit component or a flat panel display (FPD) such as an organic light emitting diode (OLED) or a liquid crystal display panel (LCD), a process of laminating various thin films is required. In particular, the organic light emitting diode display uses a thin film coated with a material such as polyimide without using a glass substrate as flexibility is recently required. In general, flexible organic light emitting diode displays are formed by thinly coating a polyimide layer on a glass substrate, and then forming a display device. Thereafter, a display is manufactured by peeling off the polyimide layer on which the display element is formed on the glass substrate.

In recent years, there is an increasing demand to increase the display area and improve flexibility, and thus, it is required to form a thin film more quickly and accurately.

According to such technical requirements, the organic light emitting diode display tends to use a process of coating and curing polyimide to a thinner thickness on a glass substrate. Since the thin film is formed in a state of being diluted in an organic solvent such as a solvent, a drying process is always required for the polyimide thin film. Conventionally, a heater installed in a drying furnace to dry the polyimide layer applied on a glass substrate A hot-air drying method in which air is heated using a fan and supplied onto the polyimide thin film to dry it, or a method of irradiating light directly onto the polyimide thin film surface using an infrared lamp was applied.

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

In the conventional hot air drying method, the drying time increases as the drying proceeds as the heat is transferred from the surface of the photosensitive material to the inside as the hot air is brought into contact with the surface of the liquid photosensitive material. The drying space in which the glass substrate needs to be moved must also be lengthened, and accordingly, in the case of the straight-type drying furnace, there is a problem in that a fairly large space is required for manufacturing.

In addition, in the hot air drying method, dust and/or foreign substances may be included in the hot air in the process of supplying air heated through a heater using a fan to dry it, and for preventing and/or removing such dust and/or foreign substances There is a problem in that the cost of installing a clean facility is high.

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

However, since the light drying method using the light source of the UV lamp and the IR lamp is irradiated with light of a specific wavelength band (for example, UV lamp is light having an ultraviolet wavelength band, IR lamp is light having an infrared wavelength band), There is a problem in that the total drying time from the surface to the inside of the polyimide thin film is additionally increased because the amount of light energy irradiated to the mid thin film is quite small.

Republic of Korea Registered Utility Model Publication No. 20-0360502 (Registered on Aug. 20, 2004)

The present invention is to solve the above problems of the prior art, and an object of the present invention is to use a broadband light source to irradiate the light with the coating liquid applied on the substrate over a wide range from the ultraviolet region to the near-infrared region, so that the coating liquid An object of the present invention is to provide a thin film drying device capable of quickly removing and drying the solvent contained therein.

In order to achieve the above object, the thin film drying apparatus according to an embodiment of the present invention irradiates light having multiple wavelengths of a broadband wavelength band onto a coating liquid applied on a substrate to wash the surface and inside of the coating liquid. a broadband light source unit having a broadband light source for drying at the same time; a light source driver connected to the broadband light source and driving the broadband light source; and a controller for controlling the operation of the light source driver, wherein the broadband light source transmits light having multiple wavelengths between an ultra violet (UV) wavelength band and a near infrared ray (NIR) wavelength band onto the substrate. characterized by investigation.

The following advantages are achieved by using the thin film drying apparatus according to an embodiment of the present invention.

1. As a broadband light source irradiated with light of a wavelength having a range of wavelengths from ultraviolet to near infrared is used, the solvent contained in the coating solution, such as polyimide, is removed as quickly as possible to remove the coating solution. can be dried.

2. Since drying of the coating liquid is remarkably faster than that of the prior art, the drying space of the drying furnace can be minimized, and accordingly, the cost required for the drying furnace installation is also minimized.

3. Because hot air is not used, there is no need to install a clean facility to prevent or remove dust and/or foreign substances.

4. Due to the advantages of 1 to 3 described above, the manufacturing cost of the final product (eg, organic light emitting diode display) is greatly reduced.

5. Due to the advantages of 1 to 3 described above, the thin film drying apparatus according to an embodiment of the present invention for manufacturing a final product (eg, an organic light emitting display) can be freely applied to an in-line method or a batch method, etc. have.

1 is a diagram schematically showing the structure of a thin film drying apparatus according to an embodiment of the present invention.
2 is a graph showing a wavelength band of light using ultraviolet and infrared light sources according to the prior art.
3 is a graph showing the graph of FIG. 2 and a wavelength band of light using the broadband light source 111 according to an embodiment of the present invention.
4 is a graph for explaining a comparison between the state of movement of heat in the hot air drying method according to the prior art and the state of irradiation of light using a broadband light source according to an embodiment of the present invention.
5 to 7 are diagrams schematically illustrating a configuration in which a plurality of broadband light sources are arranged in a direction horizontal and/or perpendicular to a transport direction of a substrate on an upper portion of a substrate according to an embodiment of the present invention.
8 is a diagram schematically illustrating a state in which a plurality of broadband light sources are connected in a series or parallel manner to one light source driver according to an embodiment of the present invention.
9 is a diagram schematically illustrating an example in which the thin film drying apparatus according to an embodiment of the present invention is implemented in an inline manner.
10 is a view schematically showing an example in which the thin film drying apparatus according to an embodiment of the present invention is implemented in a batch manner.
11 is a graph showing the experimental results for the drying rate of the solvent in the coating liquid (L) applied to the substrate over time using the thin film drying apparatus according to an embodiment of the present invention.

Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the accompanying drawings. It should be noted that in the accompanying drawings, the same components are denoted by the same reference numerals whenever possible. In addition, detailed descriptions of well-known functions and configurations that may obscure the gist of the present invention will be omitted.

1 is a diagram schematically showing the structure of a thin film drying apparatus according to an embodiment of the present invention.

Referring to FIG. 1 , the thin film drying apparatus 100 according to an embodiment of the present invention irradiates light having multiple wavelengths of a broad wavelength band on a coating liquid L applied on a substrate G to apply the application. A broadband light source unit 110 having a broadband light source 111 for drying the surface and the inside of the liquid (L) at the same time; a light source driver 120 connected to the broadband light source 111 and driving the broadband light source 111; and a control unit 130 for controlling the operation of the light source driver 120, wherein the broadband light source 111 is formed between an ultra violet (UV) wavelength band and a near infrared ray (NIR) wavelength band. Light having multiple wavelengths is irradiated onto the substrate (G).

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

Referring back to FIG. 1 , the thin film drying apparatus 100 according to an embodiment of the present invention may include a broadband light source unit 110 , a light source driver 120 , and a control unit 130 .

The broadband light source unit 110 according to an embodiment of the present invention irradiates light having multiple wavelengths of a broadband wavelength band toward the coating liquid L applied on the substrate G, and is contained in the coating liquid L. It may include a broadband light source 111 for removing the solvent, and a housing 112 in which the broadband light source 111 is accommodated. In this case, the broadband light source unit 110 according to an embodiment of the present invention may include at least one or more broadband light sources 111 .

In this case, the broadband wavelength band of the light irradiated from the broadband light source 111 may be a wavelength band including from the ultraviolet wavelength band to the near infrared wavelength band.

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

The broadband light source 111 according to an embodiment of the present invention may include at least one inert gas of Xe, Kr, Ar, Ne, and He, and in an embodiment of the present invention, Xe is the broadband light source 111 It should be noted that a gaseous xenon lamp may be used, but is not limited thereto.

2 is a graph showing a wavelength band of light using ultraviolet and infrared light sources according to the prior art, and FIG. 3 is a graph showing a wavelength band of light using a broadband light source according to an embodiment of the present invention.

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 wavelength band, that is, a relatively short wavelength band (300-600 nm) is applied. When irradiated onto the liquid (L) phase, and referring to FIG. 2(b), when an IR lamp is used, light having a wavelength of an infrared wavelength band, that is, a relatively long wavelength band (800-1100 nm), is applied to the coating solution ( L) is investigated.

That is, when a UV lamp is used as a light source in the thin film drying apparatus 100, since light of a specific wavelength band (ultraviolet wavelength band of 300-600 nm) is irradiated onto the coating liquid L, light due to a short wavelength Although the intensity of energy is large, the total amount of energy irradiation is small, so it takes a long time 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 thin film drying apparatus 100, since light of a long infrared wavelength band of 800-1100 nm is irradiated onto the coating liquid L, the intensity of light energy is weak, and in particular, the coating liquid The polyimide thin film used as (L) has a characteristic of low long-wavelength transmittance, and thus there is a problem in that drying performance and efficiency are deteriorated.

However, referring to FIG. 3 , when the broadband light source 111 according to an embodiment of the present invention is used, light having multiple wavelengths in a wavelength band of 300-1200 nm including a near-infrared wavelength band in an ultraviolet wavelength band is applied. As it is irradiated onto (L), the total energy irradiation amount is increased compared to the light source of the prior art shown in FIG. The drying time for drying the coating liquid L can be shortened as much as possible.

The graph shown in FIG. 3 described above is a graph obtained when a voltage of 1,000V is applied to a xenon lamp containing Xe gas as a broadband light source.

4 is a graph for explaining the comparison of the heat transfer state in the hot air drying method according to the prior art and the light irradiation state using the broadband light source 111 according to an embodiment of the present invention.

Referring to FIG. 4A , a hot air of air heated by a heat source (heater: not shown) and a fan (not shown) according to the prior art is supplied in a direction parallel to the surface of the coating liquid (L). Accordingly, since the coating liquid L in contact with the hot air is dried from the surface, it is difficult for the solvent present in the coating liquid L to penetrate the dried surface and cannot be removed immediately, and by hot air As the heat supplied to the surface of the coating liquid L is transferred to the inside of the coating liquid L by conduction, a considerable time is required for the solvent in the coating liquid L to be heated and removed, and ultimately the coating liquid L ), the drying time is significantly longer.

However, referring to FIG. 4B , when the broadband light source 111 according to an embodiment of the present invention is used, a wide range of wavelength bands from the broadband light source 111 (specifically, as shown in FIG. 3 ) As shown, light having multiple wavelengths including a wavelength range of 300-1200 nm) is not only irradiated to the surface of the coating liquid L, but also the irradiated light is transmitted and absorbed into the coating liquid L. Since it has sufficient energy, it is possible to dry the surface and the inside of the coating liquid L at the same time, so that the drying time of the coating liquid L can be shortened as much as possible.

5 to 7 are diagrams schematically illustrating a configuration in which a plurality of broadband light sources are arranged in a direction horizontal and/or perpendicular to the transfer direction of the substrate on the upper portion of the substrate according to an embodiment of the present invention.

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

At this time, the plurality of broadband light sources 111 are arranged in a direction perpendicular to the transfer direction of the substrate G on the upper portion of the substrate G (see FIG. 5 ), or on the upper portion of the substrate G on the upper portion of the substrate G. It may be arranged in a direction horizontal to the transport direction. (See FIG. 6) In addition, the plurality of broadband light sources 111 may be arranged in parallel with some in a vertical direction and some in a horizontal direction with respect to the transport direction of the substrate G on the upper portion of the substrate G. have. (See FIG. 7 ) In the embodiment of FIG. 7 , some of the plurality of broadband light sources 111 are arranged in a direction perpendicular to the transport direction of the substrate G, and the remaining portions of the plurality of broadband light sources 111 sequentially Although exemplarily shown as being arranged in a horizontal direction with respect to the transfer direction of the substrate (G), those skilled in the art will part of the plurality of broadband light sources 111 is arranged in a horizontal direction with respect to the transfer direction of the substrate (G) It will be fully understood that the remaining portions of the plurality of broadband light sources 111 may be sequentially arranged in a direction perpendicular to the transport direction of the substrate G.

The light source driver 120 according to an embodiment of the present invention is connected to the broadband light source 111 and may drive the broadband light source 111 .

Referring to FIGS. 8A and 8B , in the thin film drying apparatus 100 (see FIG. 1 ) according to an embodiment of the present invention, a plurality of broadband light sources 111 shown in FIGS. 5 to 7 . The single light source driver 120 is connected in a parallel manner (refer to FIG. 8(a)) or in a series manner (refer to FIG. 8(b)), so that one light source driver 120 is connected to a plurality of broadband light sources 111 ) can be driven.

Of course, it is also possible to connect and drive one broadband light source 111 to one light source driver 120 , but in order to reduce the overall size of the thin film drying apparatus 100 , one light source driver 120 is connected to a plurality of broadband light sources. It is preferable to connect and drive the light sources 111 in parallel or in series.

Referring to FIG. 9 , the thin film drying apparatus 100 (see FIG. 1 ) according to an embodiment of the present invention is, for example, a coating solution applied to the substrate G while continuously transporting the substrate G ( L) can be implemented as an in-line method of drying (In-Line Type).

At this time, the thin film drying apparatus 100 may include a transfer conveyor 200 for continuously moving the substrate (G).

That is, in the thin film drying apparatus 100 implemented in the inline method shown in FIG. 9 , a plurality of substrates G to which the coating liquid L is applied are positioned on the transfer conveyor 200 to dry the thin film 100 . You can move from the lower part of Accordingly, it is possible to perform a continuous drying process on each of the coating solutions L applied on the plurality of substrates G by the broadband light source 111 provided in the thin film drying apparatus 100 (see FIG. 1 ). Accordingly, the overall process time is greatly reduced, and mass production of the final product (eg, organic light emitting diode display) is possible.

10 is a view schematically showing an example in which the thin film drying apparatus according to an embodiment of the present invention is implemented in a batch manner.

Referring to FIG. 10 , in the thin film drying apparatus 100 (see FIG. 1 ) according to an embodiment of the present invention, the broadband light source 110 is provided in a sealed drying chamber 300 , and the coating liquid L is applied. It may be implemented as a batch type in which the substrate G is heated by putting it into the drying chamber 300 .

At this time, the drying chamber 300 provided with the broadband light source 110 of the thin film drying apparatus 100 has an inlet 301 into which the substrate G is put and an outlet 302 through which the dried substrate G is discharged. can do. In this case, in order to input and discharge the substrate G through the inlet 301 and the outlet 302 of the drying chamber 300 , for example, a substrate such as a robot arm for picking up and transferring the substrate G A pickup and transfer device (not shown) may be used.

A predetermined working space may be formed inside the drying chamber 300, and the working space is an approximately hexahedral space and may have a planar shape corresponding to the shape of the substrate G on which the coating liquid L is applied, It should be noted that the present invention is not limited thereto.

In the batch-type thin film drying apparatus 100 (see FIG. 1 ) according to an embodiment of the present invention as shown in FIG. 10 , a drying process is performed by putting a single substrate G into the drying chamber 300 . After drying, the drying process is performed in such a way that, after discharging the dried substrate G, a new substrate G is put into the drying chamber 300 to perform the drying process again.

Although not shown, those skilled in the art may implement a multi-stage drying chamber in which the plurality of drying chambers 300 are configured in multiple stages, and perform a drying process by putting each of the plurality of substrates G into each of the multi-stage drying chambers, or A plurality of spaced apart drying spaces are formed in the drying chamber 300 of the It will be fully understood that the drying process may be performed by inputting into each of the plurality of drying spaces.

Referring back to FIG. 1 , the control unit 130 according to an embodiment of the present invention may control the operation of the light source driving unit 120 , and for example, the control unit 130 may include a micro control unit (MCU). can be implemented as

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

On the other hand, the control unit 130 for the plurality of broadband light sources 111, the driving frequency in the range of 1-20Hz, the on-time (On-Time) control time in the range of 300-1000㎲, the allowable current of 100-1,200A The range, and the discharge voltage can be controlled within the range of 500-2,000V.

Hereinafter, the result of drying the coating liquid L using the broadband light source 111 according to an embodiment of the present invention will be described in detail.

11 is a graph showing the experimental results for the drying rate of the solvent in the coating liquid (L) applied to the substrate over time using the thin film drying apparatus 100 according to an embodiment of the present invention.

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

Table 1

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

Then, the polyimide solution (coating solution (L)) coated on the substrate was dried using the broadband light source 111 at the drying times defined below at 30 sets, 60 seconds, 90 seconds, and 120 seconds respectively. It was measured with an electronic balance.

At this time, the drying rate = the weight before drying of the coating solution (L) / the weight after drying of the coating solution (L) was calculated.

As shown in Table 1 and the graph of FIG. 11, when the coating liquid L was dried using the broadband light source 111, the drying rate of NMP was approximately 90% or more in 90 sec or more (completely removed NMP) dry state) was confirmed. In addition, it was confirmed that the coating thickness of the coating solution (L) after drying at 90 sec or more was 5.4 μm or less, and the coating thickness after drying was reduced by more than 90% compared to the coating thickness of the initial coating solution (L).

As can be seen from the above results, when the conventional light source was used, a long drying time of up to 5 hours or more was required for complete drying of the coating liquid L, but when the broadband light source 111 of the present invention was used, approximately 90 Since complete drying of the coating liquid L is possible only with a drying time of about seconds, it is possible to significantly shorten the drying time of the coating liquid L compared to the prior art.

As described above, the thin film drying apparatus according to an embodiment of the present invention uses a broadband light source that can be irradiated with light having multiple wavelengths of various wavelength bands from the ultraviolet region to the near infrared region, for example, a liquid photosensitizer. It is possible to dry the coating solution by removing the solvent contained in the coating solution as quickly as possible.

In addition, when the thin film drying apparatus according to an embodiment of the present invention is used, the coating liquid can be dried in a significantly faster time than in the prior art, so that the drying space of the drying furnace can be minimized, and accordingly, it is possible to install the drying furnace The required costs are also minimized.

In addition, unlike the prior art, since hot air is not used, the installation cost of a clean facility for preventing or removing dust and/or foreign substances is unnecessary.

In addition, the manufacturing cost of the final product (eg, organic light emitting diode display) is greatly reduced due to the above-mentioned advantages.

In addition, due to the above-described advantages, the thin film drying apparatus according to an embodiment of the present invention can be freely applied to an in-line method or a batch method.

As described above, the present invention has been described with reference to the accompanying drawings and exemplary embodiments, but the protection scope of the present invention is not limited to these drawings and exemplary embodiments, and any It is possible to carry out modification and transformation of

100: thin film drying device 110: broadband light source unit
111: broadband light source 112: housing
120: light source driving unit 130: control unit
G: substrate L: coating liquid

Claims (12)

In the thin film drying apparatus,
a broadband light source unit having a broadband light source for simultaneously drying a surface and an interior of the coating liquid by irradiating light having multiple wavelengths of a broadband wavelength band onto the coating liquid applied on the substrate;
a light source driver connected to the broadband light source and driving the broadband light source; and
a control unit for controlling the operation of the light source driver;
includes,
The broadband light source is provided on the upper side of the substrate,
The broadband wavelength band has a range from an ultra violet (UV) wavelength band to a near infrared ray (NIR) wavelength band, and the light having the multiple wavelengths in one region is simultaneously irradiated onto the substrate directly,
The range of the broadband wavelength band is 300nm to 1200nm thin film drying apparatus. delete According to claim 1,
The broadband light source is a thin film drying apparatus comprising at least one inert gas of Xe, Kr, Ar, Ne, and He. 4. The method of claim 3,
A thin film drying device in which a xenon lamp containing Xe gas is used as the broadband light source. According to claim 1,
The broadband light source is implemented with a plurality of broadband light sources provided on the substrate, and is arranged in either one of a horizontal direction and a vertical direction with respect to the transfer direction of the substrate, or thin film drying arranged in both directions. Device. 6. The method of claim 5,
The plurality of broadband light sources are connected to the light source driver in a parallel manner or in a series manner. 7. The method of any one of claims 1 and 3 to 6,
The broadband light source unit thin film drying apparatus further comprising a housing for accommodating the broadband light source. 7. The method of any one of claims 1 and 3 to 6,
The control unit is a thin film drying apparatus for controlling the amount of light irradiated from the broadband light source by controlling the light source driver using a pulse width modulation (PWM) method. According to claim 1,
Thin film drying apparatus further comprising a transfer conveyor for continuously transferring the substrate. According to claim 1,
Further comprising a sealed drying chamber provided with the broadband light source,
The drying chamber is provided with an inlet through which the substrate is put and an outlet through which the substrate after drying is completed.
Thin film dryer. 11. The method of claim 10,
The drying chamber is implemented as a multi-stage drying chamber in which a plurality of drying chambers are configured in multiple stages,
Each of the plurality of substrates (G) is put into each of the multi-stage drying chamber to perform a drying process.
Thin film dryer. 11. The method of claim 10,
The drying chamber forms a plurality of spaced apart drying spaces therein, and the broadband light source unit is installed in each drying space,
The substrate is put into each of the plurality of drying spaces and the drying process is performed.
Thin film dryer.

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