Coating device and coating method

Abstract

According to one embodiment, provided are a coating device and a coating method for forming a coating film by a meniscus method, which are capable of forming a uniform coating film. The coating device is provided with: a coating rod; a base material conveying member that conveys the base material; a plurality of nozzles for supplying the coating liquid to the surface of the coating rod; and a coating liquid supply means for supplying the coating liquid to the nozzles, the upstream side of each of the nozzles being provided with a coating liquid supply amount adjustment means for adjusting the supply amount of the coating liquid supplied to the nozzles.

Description

Technical Field Embodiments of the present invention relate to a coating apparatus and a coating method that can be used for device formation. Background Art Organic thin film solar cells and organic / inorganic hybrid solar cells using organic semiconductors are highly anticipated as low-cost solar cells because cheap coating methods can be applied in the formation of active layers. In order to realize organic thin film solar cells or organic / inorganic hybrid solar cells at low cost, it is required to uniformly coat the coating material forming the organic active layer or other layers. The film thickness of each layer is about a few nm to a few hundred nm, and it is required to form such a very thin layer over a large area with good uniformity. For example, as one of the roll-to-roll (R2R) coating methods that can coat extremely thin layers over a large area at low cost, a meniscus coating method is known. As a meniscus coating method, liquid is supplied from multiple nozzles to the coating rod head to obtain a single large-area coating film. The method is simple and the structure of the device is also simple. However, it is sometimes difficult to obtain a uniform film thickness, and a coating device that can form a more uniform coating film is desired. Prior art literature Patent Literature Patent Document 1: Japanese Patent Application Publication No. 2006-167532 Summary of the invention Problems to be solved by the invention An embodiment of the present invention provides a coating device and a coating method that can form a uniform coating film by a meniscus coating method and that also require simple maintenance. Means for solving problems Embodiments provided by the present invention are as follows.

[0001] A coating device for supplying a coating liquid to a surface of a substrate and forming a coating film by a meniscus method, comprising: Coating rod; A substrate conveying component for conveying the substrate; A plurality of nozzles for supplying the coating liquid to the surface of the coating rod; and a coating liquid supplying member for supplying the coating liquid to the nozzle; A coating liquid supply amount adjusting member is provided on the upstream side of each of the nozzles, and the coating liquid supply amount adjusting member adjusts the supply amount of the coating liquid supplied to the nozzles.

[0002] The coating device described in [1] further includes a coating rod position adjustment component for controlling the position of the coating rod.

[0003] The coating device described in [1] or [2] further includes a nozzle position detection unit that detects a state in which the coating rod contacts at least one of the nozzles.

[0004] The coating device described in any one of [1] to [3] further includes a nozzle position adjustment unit that independently changes the distance between the plurality of nozzles and the coating rod.

[0005] The coating device according to any one of [1] to [4] further comprises a coating liquid supply member that supplies the coating liquid to the nozzle, and the total number of the coating liquid supply members is less than the total number of the nozzles.

[0006] In the coating device described in any one of [1] to [5], the coating rod is arranged so as not to rotate.

[0007] In the coating device described in any one of [1] to [6], the nozzle is a needle-shaped device whose opening surface of the coating liquid discharge port is cut at an angle of not less than 75 degrees and not more than 105 degrees.

[0008] In the coating device described in any one of [1] to [7], the nozzle is detachable.

[0009] A coating method, wherein a meniscus of a coating liquid is formed between a coating rod and a substrate, the substrate is transported, and the coating liquid is coated on the surface of the substrate, wherein the coating liquid is supplied to a plurality of nozzles, the coating liquid is supplied from the plurality of nozzles to the surface of the coating rod and the surface of the substrate, and the supply amount of the coating liquid supplied to the plurality of nozzles is adjusted upstream of each nozzle.

[0010] In the coating method described in [9], the total number of the coating liquid supply components is less than the total number of the nozzles. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 This is a schematic side view of the coating device illustrating the first embodiment. Figure 2 This is a schematic plan view illustrating the coating device according to the first embodiment. Figure 3 This is a flowchart illustrating the coating method according to the second embodiment. DETAILED DESCRIPTION Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. In addition, the drawings are schematic or conceptual, and the relationship between the thickness and width of each part, the ratio of the size between the parts, etc. are not necessarily the same as in reality. In addition, even when representing the same part, there are cases where the sizes and ratios of each other are represented differently according to the drawings. In the present specification and each drawing, the same elements as those described above with respect to an already-appeared drawing are denoted by the same reference numerals, and detailed description thereof will be appropriately omitted. (First Embodiment) Figure 1 It is a schematic side view illustrating the coating device according to the first embodiment. Figure 2 It is a schematic plan view illustrating the coating device according to the first embodiment. like Figure 1 As shown, the coating device 100 according to the embodiment includes: a nozzle position adjustment member 108 and a coating rod 101, a mechanism 107 for detecting the distance of a nozzle 103, a coating liquid supply member 104 such as a liquid supply pump for supplying a coating liquid 110 stored in a liquid storage unit, etc., and a substrate conveying member such as conveying rollers 102a and 102b for conveying a substrate 102. A coating liquid supply amount adjustment member 105 such as an adjustment valve is arranged upstream of each nozzle. like Figure 2 As shown, the coating device in this embodiment has a plurality of nozzles 103. In addition, there may be a plurality of coating liquid supply components such as a liquid feeding pump 104. The total number of nozzles may be greater than the total number of liquid feeding pumps. In this case, the piping from one pump to each nozzle is branched, but preferably the coating liquid piping is branched into two. In an embodiment, if Figure 1 and Figure 2 As shown, the coating liquid supply amount adjusting member 105 is provided on the upstream side of the nozzle 103 . A plurality of nozzles 103 can be disposed opposite to the coating rod 101. Figure 2 As shown, a plurality of nozzles 103 can supply coating liquid 110 toward the coating rod 101 . like Figure 2 As shown, a plurality of nozzles 103 are arranged along a first direction. The first direction is, for example, the Y-axis direction. A direction perpendicular to the Y-axis direction is set as the X-axis direction. The moving direction of the substrate can be consistent with the X-axis. A direction perpendicular to the Y-axis direction and the X-axis direction is set as the Z-axis direction. The coating rod 101 extends, for example, along the Y-axis direction. like Figure 1 As shown, a meniscus 110M of the coating liquid 110 can be formed between the substrate 102 and the coating rod 101. The meniscus 110M contacts the substrate 102, and the substrate 102 is moved along the moving direction (the arrow direction in the figure), thereby forming a coating film 111 on the substrate 102. By making the coating film 111 solidified by, for example, drying, a target film (solid film) can be obtained. For example, by moving the substrate 102 along the moving direction, a large-area coating film 111 can be formed on the substrate 102. The coating liquid 110 is applied to substantially the entire surface of the substrate 102 by a coating rod, but when using a conventional general coating method, the film thickness is sometimes uneven. As a major reason for this, there is sometimes a deviation in the discharge amount between each nozzle 103. The liquid supply amount of each nozzle is roughly determined by the liquid feeding pump, but varies according to the number, length, height, diameter or blockage of the piping or nozzle. The coating liquid supply amount adjustment component, such as a valve 105 for adjusting the liquid amount, can adjust it, and can reduce the deviation of the discharge amount of the coating liquid between each nozzle. In particular, when the number of liquid feeding pumps is less than the number of nozzles, there is a tendency for the deviation to become smaller, so it is preferred. As the regulating valve 105, a ball valve, a stop valve, a gate valve, a butterfly valve, a needle valve, a diaphragm valve, an electric valve, etc. can be used. In addition, the flow rate can also be adjusted by squeezing the resin pipe with pressure. The coating apparatus of the embodiment preferably further includes a coating rod position adjustment member 106 for controlling the interval between the coating rod 101 and the substrate 102. As this member, a gap ring, a micrometer, or the like can be used. In the embodiment, the number of the plurality of nozzles 103 can be set to three or more. Thus, a large-area coating film 111 can be stably formed. Figure 2 In the example of FIG. 1 , the number of the plurality of nozzles 103 is 4. In the embodiment, the number may be any integer greater than 3. In an embodiment, the nozzle may be a slit die or a needle-shaped nozzle. By using a plurality of needle-shaped nozzles 103, for example, the discharge amount of the coating liquid 110 can be controlled with high precision. If the nozzle is needle-shaped, for example, even if there are quite a lot of nozzles, the front end of the nozzle is easy to contact the coating rod 101. In the needle-shaped nozzle, high flexibility can be obtained. Through high flexibility, for example, it is possible to suppress the nozzle from being damaged by vibration of the coating rod 101. In the needle-shaped nozzle, the length of the nozzle is, for example, greater than 10 mm and less than 100 mm, and the inner diameter of the nozzle is, for example, greater than 0.5 mm and less than 2 mm. The angle between the end face of the front end of the nozzle and the extension direction of the nozzle is, for example, about 90 degrees (for example, greater than 75 degrees and less than 105 degrees). Through such a shape, for example, it is possible to suppress damage to the coating rod 101. Furthermore, when a plurality of nozzles are arranged, the distance between the coating rod 101 and the tip of each nozzle is likely to vary. If there is a variation, the meniscus 110M formed by each nozzle is likely to be disturbed, resulting in the coating film 111 being likely to become non-uniform. In order to solve such problems, Figure 1 and Figure 2As shown in FIG. 1 , if a nozzle position adjusting member 108 for adjusting the position of each nozzle and a nozzle position detecting member 107 for detecting the distance between the coating rod 101 and each nozzle 103 are provided, the deviation of the position and distance between the front end of each nozzle and the coating rod can be reduced, and uniform coating can be performed. Specifically, the position of each nozzle detected by a nozzle position detecting member such as a camera is adjusted by a nozzle position adjusting member for physically adjusting the position of each nozzle. In an embodiment, a component for detecting the contact between the coating rod and each nozzle may also be provided. The contact can be easily and simply detected by, for example, measuring the resistance between the nozzle and the coating rod, so by adjusting the coating conditions based on this, the deviation can be reduced. If the nozzle is in contact with the coating rod, the coating liquid can be directly applied to the coating rod, and it is not easy to cause depression of the coating liquid. In an embodiment, as a component for detecting the contact between the coating rod and each nozzle, a component for measuring the resistance between each nozzle and the coating rod may be provided. If each nozzle and the coating rod are made of conductive stainless steel or the like, and each nozzle is insulated, then if the resistance between the coating rod and each nozzle is measured, the resistance decreases sharply at the moment of contact. In addition, the resistance changes by changing the contact state, so the contact state can be monitored. For example, when the nozzle is bent too much and is strongly pressed by the coating rod, the coating rod not only contacts the front end of the nozzle, but also contacts the side thereof, and the resistance becomes very small. In this case, the coating liquid is easily ejected from the front end of the nozzle to the position outside the coating rod, which easily causes uneven coating. The optimal resistance varies according to the shape and material of the nozzle and the coating rod, so it is preferably measured in advance. Preferably, wiring connected to the resistance measuring device is pre-arranged between each nozzle and on the coating rod. An opening and closing portion is provided on the wiring, and each nozzle is moved before coating to confirm the contact with the coating rod. In addition, if the resistance is also measured during coating, it is possible to detect abnormal contact between the nozzle and the coating rod. The resistance measuring device can also be an external device different from the coating device. In addition, in the coating device of the embodiment, the nozzle is preferably detachable. The nozzle is easily clogged due to a small opening. In the coating device of the embodiment, when such a clog occurs, the spray amount of each nozzle can be adjusted by the coating liquid supply component and the coating liquid supply amount adjustment component, but when the clog becomes significant or the spray cannot be completely discharged, it is necessary to clean or replace it. In such a case, by making the nozzle detachable, maintenance becomes easy, so it is preferred. The coating device 100 may further include a drying unit 112. The drying unit 112 can dry the coating liquid 111 applied to the substrate 102. The drying unit 112 may include, for example, an air nozzle or a far infrared lamp. In an embodiment, the cross-sectional shape of the coating rod 101 is arbitrary. The cross-sectional shape is, for example, circular, flat circular or polygonal. It is also possible that a portion of the cross-sectional shape corresponding to the meniscus forming portion is curved, and the other portion is linear. For example, the cross-sectional shape of the surface of the coating rod 101 opposite to the substrate 102 can be curved. The coating rod can be arranged in a non-rotating manner. By not rotating the coating rod like a roller, the stability of the meniscus is improved. The coating rod 101, for example, includes at least one selected from the group consisting of stainless steel, aluminum, titanium and glass. Thus, the processing when preparing the coating rod 101 becomes easy. In one example, the surface of the coating rod 101 is a mirror surface. In another example, the surface of the coating rod 101 may also include a concave-convex structure. (Second Embodiment) The second embodiment relates to a coating method. In the coating method of the embodiment, coating is performed using, for example, the coating device 100 (and its modifications) described in relation to the first embodiment. Figure 3 This is a flowchart illustrating the coating method ( S30 ) according to the second embodiment. The coating method of the embodiment is a coating method in which a meniscus of a coating liquid is formed between a coating rod and a substrate, the substrate is transported, and the coating liquid is coated on the surface of the substrate. Then, the coating liquid is supplied to a plurality of nozzles, and the coating liquid is supplied from the plurality of nozzles to the surface of the coating rod and the surface of the substrate. At this time, the supply amount of the coating liquid supplied to the plurality of nozzles is adjusted upstream of each nozzle. When such a method is implemented, first, the amount of coating liquid supplied to each nozzle is adjusted (S31). The amount of coating liquid supplied can be adjusted by a coating liquid supply member such as a pump or a coating liquid supply amount adjustment member disposed upstream of the nozzle. Next, the distance between the coating rod and each nozzle is detected and the distance is adjusted as needed (S32). The distance can be detected by a nozzle position detection component, etc. The distance can be adjusted by a coating rod position adjustment component or a nozzle position adjustment component. Then, when the amount of coating liquid supplied is adjusted and the positions of the coating rod and each nozzle are adjusted, a step of supplying the coating liquid to coat the substrate can be performed ( S33 ). Hereinafter, specific examples of the coating device and the coating method according to the embodiment will be described. For example, a solar cell can be formed by coating with the coating device 100. In one example, the number of pumps is 4. A tube connected to one pump is connected to four nozzles. The total number of nozzles is 16. The nozzle is set on a cantilever rod. An actuator for movement and wiring for measuring resistance are provided at each nozzle. A liquid volume adjustment valve is provided at each nozzle. The wiring is connected to a resistance meter. A nozzle position detection component, such as a camera, is provided for observing the positional relationship between the nozzle and the coating rod. For example, the substrate 102 is a rolled PET film. The width of the PET film is, for example, 330 mm. A light-transmitting electrode with a width of 300 mm is produced on the PET film by a roll-to-roll corresponding sputtering device. The sheet resistance of the electrode is, for example, 10Ω / □. The electrode has, for example, a stacked structure of ITO film / Ag alloy / ITO film. For example, a plurality of electrodes are provided. The length of one of the plurality of electrodes is, for example, approximately 10 mm. The interval between the plurality of electrodes is, for example, 50 μm. The cross-sectional shape of the coating rod 101 is circular. The radius of the circle is 10 mm. The length of the coating rod 101 is 300 mm. The coating rod 101 is made of, for example, stainless steel (for example, SUS303). The nozzle includes a stainless steel locking base. The length of the nozzle is 50 mm. The coating liquid pipe is a polytetrafluoroethylene pipe. A liquid volume adjustment valve is provided between the pipe and the nozzle. The valve and the pipe are connected by a detachable joint. The pipe is connected to a pump. In one example, the hole transport layer is formed from the coating liquid 110. In this case, the coating liquid 110 is an aqueous solution containing PEDOT and PSS. For example, the relative position relationship between the coating rod 101 and the substrate 102 is controlled by a gap ring or an actuator. For example, the nozzle is made horizontal. In this state, the coating liquid 110 is supplied and the air in the nozzle is exhausted. Then, the pump and the liquid amount adjustment valve are adjusted so that the coating liquid flows out uniformly from each nozzle. Then, the tip of the needle nozzle is lowered and tilted, for example, by 20° from the horizontal. The cantilever rod is brought close to the coating rod. Next, each nozzle is brought close to the coating rod one by one and brought into contact with the coating rod, so that the resistance becomes 10 to 50Ω. The coating liquid 110 is continuously supplied by a pump while the substrate 102 is conveyed. The moving speed of the substrate 102 is, for example, 5 m / min. The drying unit 112 blows heated dry air to the applied coating liquid 110. A solidified coating film is obtained from the coating liquid 110. In an embodiment, other coating liquids may be further applied after the above-mentioned coating. Other coating liquids, for example, contain semiconductor materials. Other coating liquids, for example, contain PTB7 ([poly{4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b']dithiophene-2,6-diyl-1t-alt-3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]thiophene-4,6-diyl}]) and PC70BM ([6,6]phenyl C71butyric acid methyl ester). PTB7 is, for example, a p-type semiconductor. PC70BM is, for example, an n-type semiconductor. Other coating liquids, for example, further contain monochlorobenzene. The amount of PTB7 is 8 mg relative to 1 mL of monochlorobenzene. The amount of PC70BM is 12 mg relative to 1 mL of monochlorobenzene. Other coating liquids are dispersions containing organic semiconductors. Other coating liquids, for example, become semiconductor films of solar cells. In coating other coating liquids, the minimum gap distance between the coating rod 101 and the substrate 102 is 300 μm. The moving speed of the substrate 102 is, for example, 5 m / min. After coating, the drying unit 112 is used for drying. For example, there are organic thin film solar cells using organic semiconductors, or organic / inorganic hybrid solar cells. By manufacturing these solar cells using a coating method, high-performance solar cells can be manufactured. In the embodiment, the coating liquid 110 may be applied to the substrate 102 at a position where the substrate 102 is conveyed in a vertical direction. In this way, for example, the effect of gravity is applied to the meniscus, and a uniform film can be easily obtained even at a high speed. According to an embodiment, a coating device and a coating method capable of forming a uniform coating film are provided. The embodiments of the present invention are described above with reference to specific examples. However, the present invention is not limited to these specific examples. For example, the specific structure of each element such as a tube, a pump, a nozzle, and a holding portion included in the coating device is included in the scope of the present invention as long as a person skilled in the art can implement the present invention in the same manner and obtain the same effect by appropriately selecting from the known range. Furthermore, embodiments in which two or more elements of the specific examples are combined within a technically possible range are also included in the scope of the present invention as long as they include the gist of the present invention. In addition, as embodiments of the present invention, all coating devices and coating methods that can be appropriately designed and modified by those skilled in the art based on the above-mentioned coating head, coating device and coating method also belong to the scope of the present invention as long as they include the gist of the present invention. Furthermore, within the scope of the concept of the present invention, a person skilled in the art can conceive of various changes and modifications, and it is understood that these changes and modifications also belong to the scope of the present invention. Several embodiments of the present invention have been described, but these embodiments are presented as examples and are not intended to limit the scope of the invention. These new embodiments can be implemented in various other ways, and various omissions, substitutions, and changes can be made without departing from the scope of the invention. These embodiments and their variations are included in the scope or spirit of the invention, and are included in the invention described in the scope of the request and its equivalent. Marking Description 100…Coating device 101…Coating rod 102…Base material 102a, 102b ... conveying mechanism 103…Nozzle 104…Pump 105 ...Coating liquid supply amount adjustment component 106…Coating rod position adjustment parts 107…Nozzle distance detection component 108…Nozzle position adjustment parts 109…liquid storage part 110…Coating liquid 111…Coating film 112…Drying parts

Claims

1. A coating device for supplying a coating liquid to a surface of a substrate and forming a coating film by a meniscus method, comprising: Coating rod; A substrate conveying component for conveying the substrate; A plurality of nozzles for supplying the coating liquid to the surface of the coating rod; and a coating liquid supplying member for supplying the coating liquid to the nozzle; A coating liquid supply amount adjusting member is provided on the upstream side of each of the nozzles, and the coating liquid supply amount adjusting member adjusts the amount of coating liquid supplied to the nozzles.

2. The coating device according to claim 1, wherein: A coating rod position adjusting member for controlling the position of the coating rod is further provided.

3. The coating device according to claim 1 or 2, wherein: The device further includes a nozzle position detection unit configured to detect that the coating rod is in contact with at least one of the nozzles.

4. The coating device according to claim 1 or 2, wherein: The invention further includes a nozzle position adjusting member for independently changing the distance between the plurality of nozzles and the coating rod.

5. The coating device according to claim 1 or 2, wherein: The invention further comprises a coating liquid supplying member for supplying the coating liquid to the nozzle, wherein the total number of the coating liquid supplying members is less than the total number of the nozzles.

6. The coating device according to claim 1 or 2, wherein: The coating rod is arranged in a non-rotating manner.

7. The coating device according to claim 1 or 2, wherein: The nozzle is a needle-shaped nozzle whose opening surface of the coating liquid discharge port is cut at an angle of not less than 75 degrees and not more than 105 degrees.

8. The coating device according to claim 1 or 2, wherein: The nozzle is detachable.

9. A coating method, comprising forming a meniscus of a coating liquid between a coating rod and a substrate, conveying the substrate, and coating the coating liquid on the surface of the substrate, wherein: The coating liquid is supplied to a plurality of nozzles, and the coating liquid is supplied from the plurality of nozzles to the surface of the coating rod and the surface of the substrate, and the supply amount of the coating liquid supplied to the plurality of nozzles is adjusted upstream of each nozzle.

10. The coating method according to claim 9, wherein: The total number of the coating liquid supplying members is smaller than the total number of the nozzles.

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