Coating head, coating device, and coating method

Abstract

According to an embodiment, a coating head, a coating apparatus, and a coating method are provided, capable of forming a uniform coating film and forming a coating film by slit coating. The coating head is provided with: a manifold in which a coating liquid is temporarily stored; a slit for discharging the coating liquid stored in the manifold; and a plurality of coating liquid supply ports for introducing a coating liquid into the manifold, the manifold having a columnar shape and being disposed substantially parallel to the longitudinal direction of the coating head inside the coating head, the plurality of coating liquid supply ports being disposed at both ends of the manifold in the longitudinal direction.

Description

Technical Field

[0001] Embodiments of the present invention relate to a coating head, a coating apparatus, and a coating method that can be used for device formation. Background Art

[0002] Organic thin film solar cells and organic / inorganic hybrid solar cells using organic semiconductors can apply cheap coating methods in the formation of active layers, and are therefore expected to be low-cost solar cells. In order to realize organic thin film solar cells and organic / inorganic hybrid solar cells at low cost, it is required to uniformly apply the coating materials forming the organic active layer and 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 with good uniformity over a large area. For example, as one of the roll-to-roll (R2R) coating methods that can apply extremely thin layers over a large area at low cost, a slit coating method is known. In slit coating, a coating liquid can be supplied to a substrate from a slit with a wider width, and a single large-area coating film can be easily obtained. However, in the previous slit coating, the discharge amount of the coating liquid in the length direction of the slit is prone to differences, and it is sometimes difficult to obtain a coating film with uniform film thickness. Therefore, it is desired to form a coating head, a coating device, and a coating method that can form a more uniform coating film.

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2013-215644 Summary of the invention

[0006] Problems to be solved by the invention

[0007] Embodiments of the present invention provide a coating head, a coating device, and a coating method capable of forming a uniform coating film by slit coating.

[0008] Means for solving problems

[0009] The embodiments provided by the present invention are as follows.

[0010] [1] A coating head for slit coating, discharging a coating liquid from the slit, wherein:

[0011] The coating head has:

[0012] A manifold that temporarily stores the coating liquid inside;

[0013] a slit for discharging the coating liquid accumulated in the manifold; and

[0014] A plurality of coating liquid supply ports are provided to introduce the coating liquid into the manifold.

[0015] The manifold has a columnar shape and is disposed inside the coating head substantially parallel to the longitudinal direction of the coating head.

[0016] The plurality of coating liquid supply ports are arranged at both ends of the manifold in the longitudinal direction.

[0017] [2] In the coating head described in [1],

[0018] The gap at the center portion in the longitudinal direction of the slit is wider than the gap at the end portions in the longitudinal direction.

[0019] [3] In the coating head described in [1] or [2],

[0020] A further coating liquid supply port for introducing the coating liquid is provided in the central portion of the manifold.

[0021] [4] In the coating head described in any one of [1] to [3],

[0022] The inner side surface of the slit has a concavo-convex structure.

[0023] [5] In the coating head described in any one of [1] to [4],

[0024] The outer side surface of the coating head exposed by the slit is a curved surface.

[0025] [6] In the coating head described in any one of [1] to [4],

[0026] The outer side surface of the coating head exposed by the slit is a flat surface.

[0027] [7] A coating device for supplying a coating liquid to a surface of a substrate to form a coating film by slit coating, comprising:

[0028] Applicator head;

[0029] a substrate conveying component for conveying a substrate; and

[0030] a coating liquid supplying member for supplying the coating liquid to the coating head;

[0031] The coating head has:

[0032] A manifold temporarily storing the coating liquid inside;

[0033] a slit for discharging the coating liquid accumulated in the manifold; and

[0034] A plurality of coating liquid supply ports are provided to introduce the coating liquid into the manifold.

[0035] The manifold has a columnar shape and is disposed inside the coating head substantially parallel to the longitudinal direction of the coating head.

[0036] The plurality of coating liquid supply ports are arranged at both ends of the manifold in the longitudinal direction.

[0037] [8] In the coating device described in [7],

[0038] The coating device further includes a coating head position adjusting member for controlling the position of the coating head.

[0039] [9] In the coating device described in [7] or [8],

[0040] The coating liquid is supplied to the coating head from a coating liquid supplying member.

[0041]

[10] A coating method for applying a coating liquid onto a substrate through a slit using a coating head, wherein:

[0042] The coating head has:

[0043] A manifold temporarily stores the coating liquid inside;

[0044] a slit for discharging the coating liquid accumulated in the manifold; and

[0045] A plurality of coating liquid supply ports are provided to introduce the coating liquid into the manifold.

[0046] The manifold has a columnar shape and is disposed inside the coating head substantially parallel to the longitudinal direction of the coating head.

[0047] The plurality of coating liquid supply ports are arranged at both ends of the manifold in the longitudinal direction.

[0048] The coating liquid is supplied to the plurality of coating liquid supply ports to perform coating.

[0049]

[11] In the coating method described in

[10] ,

[0050] The coating was performed with the slit facing upward. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] Figure 1 This is a schematic diagram showing a coating state using the coating head according to the first embodiment.

[0052] Figure 2 This is a schematic cross-sectional view of the coating head according to the first embodiment, taken in a direction perpendicular to the longitudinal direction.

[0053] Figure 3 This is a schematic cross-sectional view of the coating head according to the first embodiment, taken in a direction parallel to the longitudinal direction.

[0054] Figure 4 This is a schematic side view illustrating a coating device according to a second embodiment.

[0055] Figure 5 This is a flowchart illustrating the coating method according to the third embodiment. DETAILED DESCRIPTION

[0056] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0057] In addition, the drawings are schematic or conceptual, and the relationship between the thickness and width of each part, the size ratio between parts, etc. are not necessarily limited to the same as in reality. Even when representing the same part, the size and ratio of each other may be represented differently depending on the drawings.

[0058] In the present specification and each drawing, the same elements as those described in the drawings already shown are denoted by the same reference numerals, and detailed description thereof will be appropriately omitted.

[0059] (First embodiment)

[0060] Figure 1 Schematic diagram showing the coating state using the coating head of the first embodiment. Figure 2 as well as Figure 3 It is a schematic cross-sectional view showing the application head of the first embodiment in the directions perpendicular to and parallel to the longitudinal direction.

[0061] like Figure 1 As shown in the schematic diagram of the first embodiment, the coating device 100 is Figure 2 In the coating head of the cross section shown in FIG. 1 , a coating liquid 102 is discharged from a slit 101, and a coating liquid supply port 103 is provided for supplying the coating liquid from both ends in the longitudinal direction of the coating head. Also shown in the figure are a substrate 104, a coating film 105, a pipe 106 for supplying the coating liquid to the coating head, a liquid delivery pump 107 as a coating liquid supply member, and a coating liquid tank 108.

[0062] By supplying the coating liquid from both ends of the coating head in the longitudinal direction, the coating liquid can be easily discharged uniformly from the slit even if the length of the coating head in the longitudinal direction is 30 cm or more, or even 1 m or more.

[0063] like Figure 3 As shown, a manifold 112 for temporarily retaining the coating liquid and a flow path 111 from the coating liquid supply port 103 to the manifold are arranged in the slit internal structure of the coating head 100. In addition, a concave-convex structure can be provided on the inner surface of the slit 101. The manifold has a columnar shape and is arranged in the interior of the coating head substantially parallel to its longitudinal direction.

[0064] If the coating liquid is supplied from both sides of the manifold disposed inside the coating head in the longitudinal direction, the coating liquid 102 collides in the center and the pressure locally rises, or turbulence is easily generated. Such pressure fluctuations and turbulence may cause coating deviations, but the manifold 112 and the concavo-convex structure provided on the inner surface of the slit play a role in alleviating these.

[0065] The coating head of the first embodiment may also have a constant gap of the slit 101. However, the gap in the center of the slit in the longitudinal direction may be wider than the gap in the end of the slit in the longitudinal direction. This makes it easy to suppress the local increase in pressure of the coating liquid and the generation of turbulence.

[0066] The coating head 100 of the first embodiment has coating liquid supply ports on both sides of the manifold disposed inside the coating head in the longitudinal direction, but a coating liquid supply port for supplying liquid may be further provided in the center of the manifold 112. This makes it easier to uniformly discharge liquid from the slit.

[0067] The coating head of the first embodiment is such that the outer side surface 109 of the slit 101 can be Figure 2 Here, the outer side surface refers to the portion that can be contacted by the coating liquid. By setting the outer side surface 109 as a curved surface, even if the distance between the slit 101 and the substrate 104 changes, the variation of the coating film thickness can be reduced. The range of the outer side surface of the shape that should be considered is 2 to 5 times the width of the slit. In addition, Figure 2 In the embodiment, the cross-section of the coating rod perpendicular to the longitudinal direction is circular, but the cross-sectional shape is not particularly limited.

[0068] In addition, in the coating head of the first embodiment, the outer side surface 109 of the slit 101 may also be a plane. By making the outer side surface a plane, the shear stress becomes high, and a uniform coating film can be easily obtained when the viscosity of the coating liquid is high. In this case, the range of the outer side surface is also 2 to 5 times the slit width.

[0069] (Second embodiment)

[0070] like Figure 4 As shown, the coating device 200 of the second embodiment includes: a coating head 100 having a slit 101 ; a substrate transport member 110 for transporting a substrate 104 ; and a pump 107 as a coating liquid supply member for supplying a coating liquid 102 to the coating head 100 .

[0071] like Figure 4As shown, a coating film 105 based on the coating liquid 102 is formed on a substrate 104. The coating film 105 is cured by, for example, drying, thereby obtaining a target film (solid film). For example, by moving the substrate 104 along a moving direction (the direction of the arrow in the figure), a large-area coating film 105 can be formed on the substrate 104.

[0072] The coating device of the second embodiment can include a coating head position adjustment member 113 for controlling the position of the coating head. The coating film can be made uniform in thickness by detecting the position of the coating head before or during coating and controlling the distance between the coating head and the substrate while coating.

[0073] The coating device of the second embodiment can supply the coating liquid 102 from a liquid feeding pump 107. The pipes from the liquid feeding pump are divided into a plurality of pipes and connected to the coating head respectively. When the liquid feeding pump 107 is located below the coating head 100, the air in the coating liquid is easily discharged. In addition, the coating liquid tank 108 can also be located below the pump 107.

[0074] The coating device 200 may further include a drying unit 114. The drying unit 114 can dry the coating liquid 102 applied to the substrate 104. The drying unit 114 may include, for example, an air nozzle or a far-infrared lamp.

[0075] (Third embodiment)

[0076] The third embodiment relates to a coating method. In the coating method of the embodiment, coating is performed using, for example, the coating device 200 (and its modifications) described in relation to the first embodiment.

[0077] Figure 5 This is a flowchart illustrating a coating method (S30) according to the third embodiment. This coating method performs coating using the coating head according to the first embodiment or the coating device according to the second embodiment.

[0078] This method is a method for coating by discharging a coating liquid from a coating head having a slit, and comprises: a step (S31) of preparing a coating head for supplying coating liquid from both sides of the coating head in the length direction as shown in Implementation 1; a step (S32) of detecting and adjusting the distance between the coating head and the substrate; and a step (S33) of coating the substrate while supplying liquid from both ends of the coating head in the length direction of the slit.

[0079] exist Figure 4An example of a coating device configured with the slit facing downward is shown in FIG. Although the direction of the slit can be freely selected to be downward, sideways, or upward, if the coating liquid is discharged upward, the air in the coating liquid is easily discharged and uniform pressure is easily applied to the coating liquid, which tends to enable stable coating, and is therefore more preferred.

[0080] Hereinafter, specific examples of the coating device and coating method according to the embodiment will be described.

[0081] For example, a solar cell can be formed by coating by the coating device 200. In one example, the number of pumps is 1. A pipe connected to one pump is divided into two and connected to the coating head.

[0082] For example, the substrate 104 is a roll-shaped PET film. The width of the PET film is, for example, 330 mm. On the PET film, an electrode having light transmittance and a width of 300 mm is produced by a sputtering device corresponding to a roll-to-roll. 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, about 10 mm. The interval between the plurality of electrodes is, for example, 50 μm.

[0083] Prepare the coating head 100 described in Embodiment 1. The width of the slit of the coating head 10 is 0.5 mm at the end and 1.0 mm in the center. The cross section of the outer side is arc-shaped. The radius of the arc is 10 mm. The length of the coating head is 300 mm. The material of the coating head is, for example, stainless steel (e.g., SUS303).

[0084] In one example, the hole transport layer is formed by the coating liquid 102. In this case, the coating liquid 102 is an aqueous solution containing PEDOT and PSS.

[0085] For example, the relative position relationship between the coating head and the substrate is controlled by a gap ring or an actuator.

[0086] The coating liquid 102 is continuously supplied by the liquid feeding pump 107 while the substrate is conveyed. The moving speed of the substrate 104 is, for example, 5 m / min. The drying unit 114 blows heated dry air onto the applied coating liquid 102. A cured coating film is obtained from the coating liquid.

[0087] 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-1-t-alt-3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4,4-b]thiophene-4,6-diyl}) and PC70BM ([6,6]phenyl C71-butyric acid methyl ester). PTB7 is, for example, a p-type semiconductor. PC70BM is, for example, an n-type semiconductor. Other coating liquids, for example, also 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 22A are dispersions containing organic semiconductors.

[0088] The other coating liquids, for example, become semiconductor films of solar cells. In the coating of the other coating liquids, the minimum gap distance between the coating head 100 and the substrate 104 is 300 μm. The moving speed of the substrate 102 is, for example, 5 m / min. After coating, the substrate 102 is dried by a drying unit.

[0089] For example, there are organic thin film solar cells or organic / inorganic hybrid solar cells using organic semiconductors. These solar cells can be manufactured by a coating method, thereby making it possible to manufacture high-performance solar cells.

[0090] In the embodiment, the coating liquid may be applied to the substrate at a position where the substrate 104 is transported in the vertical direction. In this way, for example, gravity is applied to the meniscus, and a uniform film can be easily obtained even at a high speed.

[0091] According to the embodiment, a coating device and a coating method capable of forming a uniform coating film are provided.

[0092] 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, as long as a person skilled in the art can appropriately select from the known range to implement the present invention in the same manner and obtain the same effect, the specific configuration 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.

[0093] Furthermore, any configuration obtained by combining two or more elements in each specific example within a technically possible range is included in the scope of the present invention as long as it includes the gist of the present invention.

[0094] Furthermore, all coating devices and coating methods that can be implemented by those skilled in the art by appropriately designing and modifying the coating head, coating device, and coating method described above as embodiments of the present invention are within the scope of the present invention as long as they include the gist of the present invention.

[0095] Furthermore, within the scope of the concept of the present invention, those skilled in the art can conceive of various changes and modifications, and these changes and modifications are also understood to be included in the scope of the present invention.

[0096] 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 and purpose of the invention, and are included in the invention described in the scope of the patent claim and the scope equivalent thereto.

[0097] Explanation of symbols

[0098] 100: coating head; 101: slit; 102: coating liquid; 103: supply port; 104: substrate; 105: coating film; 106: piping; 107: coating liquid supply component; 108: coating liquid tank; 109: outer side; 110: substrate conveying component; 111: flow path; 112: manifold; 113: coating head position component; 114: drying component; 200: coating device.

Claims

1. A coating head for slit coating, discharging coating liquid from the slit, wherein: The coating head has: A manifold that temporarily stores the coating liquid inside; a slit for discharging the coating liquid accumulated in the manifold; and A plurality of coating liquid supply ports are provided to introduce the coating liquid into the manifold. The manifold has a columnar shape and is disposed inside the coating head substantially parallel to the longitudinal direction of the coating head. The plurality of coating liquid supply ports are arranged at both ends of the manifold in the longitudinal direction.

2. The coating head according to claim 1, wherein: The gap at the center portion in the longitudinal direction of the slit is wider than the gap at the end portions in the longitudinal direction.

3. The coating head according to claim 1 or 2, wherein: A further coating liquid supply port for introducing the coating liquid is provided in the central portion of the manifold.

4. The coating head according to claim 1 or 2, wherein: The inner side surface of the slit has a concavo-convex structure.

5. The coating head according to claim 1 or 2, wherein: The outer side surface of the coating head exposed by the slit is a curved surface.

6. The coating head according to claim 1 or 2, wherein: The outer side surface of the coating head exposed by the slit is a flat surface.

7. A coating device for supplying a coating liquid to a surface of a substrate to form a coating film by slit coating, comprising: Applicator head; a substrate conveying component for conveying a substrate; and a coating liquid supplying member for supplying the coating liquid to the coating head; The coating head has: A manifold temporarily storing the coating liquid inside; a slit for discharging the coating liquid accumulated in the manifold; and A plurality of coating liquid supply ports are provided to introduce the coating liquid into the manifold. The manifold has a columnar shape and is disposed inside the coating head substantially parallel to the longitudinal direction of the coating head. The plurality of coating liquid supply ports are arranged at both ends of the manifold in the longitudinal direction.

8. The coating device according to claim 7, wherein: The coating device further includes a coating head position adjusting member for controlling the position of the coating head.

9. The coating device according to claim 7 or 8, wherein: The coating liquid is supplied to the coating head from a coating liquid supplying member.

10. A coating method, comprising applying a coating liquid on a substrate through a slit using a coating head, wherein: The coating head has: A manifold temporarily stores the coating liquid inside; a slit for discharging the coating liquid accumulated in the manifold; and A plurality of coating liquid supply ports are provided to introduce the coating liquid into the manifold. The manifold has a columnar shape and is disposed inside the coating head substantially parallel to the longitudinal direction of the coating head. The plurality of coating liquid supply ports are arranged at both ends of the manifold in the longitudinal direction. The coating liquid is supplied to the plurality of coating liquid supply ports to perform coating.

11. The coating method according to claim 10, wherein: The coating was performed with the slit facing upward.

Images