Coating head, coating device, and coating method

Abstract

The embodiments of the present invention provide a coating head, a coating device, and a coating method that are for forming a coating film by slit coating and make it possible to form a uniform coating film. The coating head comprises a manifold inside which a coating liquid is stored temporarily, a slit for discharging the coating liquid stored in the manifold, and a plurality of coating liquid supply ports for introducing coating liquid into the manifold. The manifold has a columnar shape and is arranged inside the coating head so as to be substantially parallel to the lengthwise direction thereof. The plurality of coating liquid supply ports are disposed on both ends of the manifold in the lengthwise direction thereof.

Description

[Technical Field]

[0001] SUMMARY OF THE INVENTION An embodiment of the present invention relates to a coating head, a coating apparatus, and a coating method that can be used to form a device. [Background technology]

[0002] Organic thin-film solar cells and organic / inorganic hybrid solar cells using organic semiconductors are expected to be low-cost solar cells because inexpensive coating methods can be used to form the active layer. To realize these solar cells at low cost, it is necessary to uniformly coat the coating materials that form the organic active layer and other layers. The thickness of each layer ranges from a few nanometers to a few hundred nanometers, and it is necessary to uniformly form these extremely thin layers over large areas. For example, slit coating is known as a roll-to-roll (R2R) coating method that can coat ultrathin layers over large areas at low cost. Slit coating allows the coating solution to be supplied to the substrate through a wide slit, making it easy to obtain a single large-area coating film. However, conventional slit coating tends to have differences in the amount of coating solution dispensed along the length of the slit, making it difficult to obtain a coating film with a uniform thickness. Therefore, coating heads, coating devices, and coating methods that can form more uniform coating films are desired. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-215644 Summary of the Invention [Problem to be solved by the invention]

[0004] The embodiments of the present invention provide a coating head, a coating device, and a coating method that can form a uniform coating film by slit coating. [Means for solving the problem]

[0005] The embodiments provided by the present invention are as follows. [1] A coating head used for slit coating that ejects a coating liquid from a slit, The coating head includes a manifold for temporarily storing a coating liquid therein; a slit for discharging the coating liquid stored in the manifold; a plurality of coating liquid supply ports for introducing coating liquids into the manifold; Equipped with the manifold has a columnar shape and is disposed inside the coating head so as to be substantially parallel to the longitudinal direction thereof; The coating head has the plurality of coating liquid supply ports disposed at both ends of the manifold in the longitudinal direction. [2] The coating head according to [1], wherein the gap at the longitudinal center of the slit is wider than the gap at the longitudinal ends. [3] The coating head according to [1] or [2], further comprising a coating liquid supply port for introducing a coating liquid into a central portion of the manifold. [4] The coating head according to any one of [1] to [3], wherein the inner surface of the slit has an uneven structure. [5] The coating head according to any one of [1] to [4], wherein the outer surface of the coating head where the slit is exposed is a curved surface. [6] The coating head according to any one of [1] to [4], wherein the outer surface of the coating head where the slit is exposed is flat. [7] A coating device for supplying a coating liquid to a surface of a substrate and forming a coating film by slit coating, A coating head; a substrate transport member that transports the substrate; a coating liquid supply member that supplies the coating liquid to the coating head; Equipped with The coating head includes: a manifold for temporarily storing the coating liquid therein; a slit for discharging the coating liquid stored in the manifold; a plurality of coating liquid supply ports for introducing coating liquids into the manifold; Equipped with the manifold has a columnar shape and is disposed inside the coating head so as to be substantially parallel to the longitudinal direction thereof; The coating device has the plurality of coating liquid supply ports disposed at both ends of the manifold in the longitudinal direction. [8] The coating device according to [7], further comprising a coating head position adjusting member for controlling the position of the coating head. [9] The coating device according to [7] or [8], wherein the coating liquid is supplied to the coating head from one coating liquid supply member.

[10] A coating method for applying a coating liquid to a substrate by slit coating using a coating head, comprising: The coating head a manifold for temporarily storing the coating liquid therein; a slit for discharging the coating liquid stored in the manifold; a plurality of coating liquid supply ports for introducing coating liquids into the manifold; Equipped with the manifold has a columnar shape and is disposed inside the coating head so as to be substantially parallel to the longitudinal direction thereof; the plurality of coating liquid supply ports are arranged at both ends of the manifold in the longitudinal direction, a coating method in which coating is performed by supplying a coating liquid to the plurality of coating liquid supply ports.

[11] The coating method according to

[10] , wherein the coating is performed with the slit facing upward. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 1 is a schematic diagram showing a coating state using a coating head according to the first embodiment. [Figure 2]FIG. 2 is a schematic cross-sectional view of the application head according to the first embodiment in a direction perpendicular to the longitudinal direction. [Figure 3] FIG. 3 is a schematic cross-sectional view of the application head according to the first embodiment in a direction parallel to the longitudinal direction. [Figure 4] FIG. 4 is a schematic side view illustrating the coating apparatus according to the second embodiment. [Figure 5] FIG. 5 is a flowchart illustrating the coating method according to the third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0007] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0008] 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 the same as those in reality. Furthermore, even when the same part is shown, the dimensions and ratios may be different depending on the drawing. In the present specification and the drawings, elements similar to those described above with reference to the previous drawings are designated by the same reference numerals, and detailed descriptions thereof will be omitted as appropriate.

[0009] (First embodiment) Fig. 1 is a schematic diagram showing a coating state using a coating head according to the first embodiment, and Fig. 2 and Fig. 3 are schematic cross-sectional views in directions perpendicular and parallel to the longitudinal direction of the coating head according to the first embodiment.

[0010] As shown in the schematic diagram of Fig. 1, a coating device 100 according to the first embodiment has a coating head that ejects a coating liquid 102 from a slit 101 whose cross section is shown in Fig. 2, and the coating head has coating liquid supply ports 103 that supply the coating liquid from both ends in the longitudinal direction of the coating head. The figure also shows a substrate 104, a coating film 105, a pipe 106 that supplies the coating liquid to the coating head, a liquid feed pump 107 that is a coating liquid supply member, and a coating liquid tank 108.

[0011] By supplying the coating liquid from both ends of the coating head in the longitudinal direction, it becomes easy to uniformly discharge the coating liquid 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.

[0012] As shown in Fig. 3, the internal structure of the slit of the coating head 100 includes a manifold 112 in which the coating liquid temporarily stays, and a flow path 111 leading from the coating liquid supply port 103 to the manifold. An uneven structure can be provided on the inner surface of the slit 101. The manifold has a columnar shape and is disposed inside the coating head, approximately parallel to the longitudinal direction thereof.

[0013] If the coating liquid is supplied from both longitudinal sides of the manifold disposed inside the coating head, the coating liquid 102 will collide in the center, causing a localized increase in pressure and turbulence. Such pressure fluctuations and turbulence can cause coating variations, but the manifold 112 and the uneven structure provided on the inner surface of the slit have the effect of mitigating these problems.

[0014] In the coating head according to the first embodiment, the gap of the slit 101 may be constant. However, the gap at the longitudinal center of the slit can be made wider than the gap at the longitudinal ends. This makes it easier to suppress local increases in pressure of the coating liquid and the occurrence of turbulence.

[0015] The coating head 100 according to the first embodiment has coating liquid supply ports on both sides in the longitudinal direction of the manifold disposed inside the coating head, and can further have a coating liquid supply port that supplies liquid to the center of the manifold 112. This makes it easier to discharge the liquid uniformly from the slits.

[0016] In the coating head according to the first embodiment, the outer surface 109 of the slit 101 can be curved as shown in FIG. 2. Here, the outer surface refers to the portion with which the coating liquid can come into contact. By making the outer surface 109 a curved surface, it is possible to reduce fluctuations in the coating film thickness even if the distance between the slit 101 and the substrate 104 fluctuates. The range of the outer surface for which the shape should be considered is 2 to 5 times the slit width. Note that in FIG. 2, the cross section perpendicular to the longitudinal direction of the coating bar has a circular shape, but the cross-sectional shape is not particularly limited.

[0017] Furthermore, the coating head according to the first embodiment may have a flat outer surface 109 of the slit 101. By making the outer surface flat, shear stress increases, and when the viscosity of the coating liquid is high, a uniform coating film can be easily obtained. Even in this case, the area of ​​the outer surface is 2 to 5 times the width of the slit.

[0018] (Second embodiment) As shown in Figure 4, the coating device 200 according to 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 which is a coating liquid supply member for supplying a coating liquid 102 to the coating head 100.

[0019] 4, a coating film 105 is formed on a substrate 104 from the coating liquid 102. The coating film 105 is solidified, for example, by drying, to obtain a desired film (solid film). For example, by moving the substrate 104 along the moving direction (the direction of the arrow in the figure), a coating film 105 with a large area can be formed on the substrate 104.

[0020] The coating device according to the second embodiment can be equipped with a coating head position adjustment member 113 that controls the position of the coating head. 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, it is possible to make the thickness of the coating film uniform.

[0021] The coating device according to the second embodiment can supply the coating liquid 102 from one liquid supply pump 107. The piping from one liquid supply pump is divided into multiple parts, and each part is connected to the coating head. If the liquid supply pump 107 is located below the coating head 100, air present in the coating liquid can be easily removed. In addition, it is preferable that the coating liquid tank 108 is located below the pump 107.

[0022] The coating device 200 may further include a drying member 114. The drying member 114 is capable of drying the coating liquid 102 applied to the substrate 104. The drying member 114 may include, for example, an air nozzle or a far-infrared lamp.

[0023] (Third embodiment) The third embodiment relates to a coating method. In the coating method according to the embodiment, coating is performed using, for example, the coating apparatus 200 (and its modifications) described in relation to the first embodiment.

[0024] 5 is a flow chart illustrating a coating method (S30) according to the third embodiment. This coating method is performed using the coating head according to the first embodiment or the coating device according to the second embodiment.

[0025] This method is a method of applying a coating liquid by ejecting it from a coating head having a slit, and includes the steps of preparing a coating head that supplies coating liquid from both sides of the coating head in the longitudinal direction, as shown in embodiment 1 (S31), detecting and adjusting the distance between the coating head and the substrate (S32), and applying the liquid to the substrate while supplying the liquid from both ends of the coating head in the longitudinal direction of the slit (S33).

[0026] An example of a coating device in which the slit is positioned so that it faces downward is shown in Figure 4. The direction of the slit can be freely selected to face downward, sideways, or upward, but ejecting the coating liquid upward is preferable because it makes it easier to remove air from the coating liquid and also makes it easier to apply uniform pressure to the coating liquid, which tends to result in stable coating.

[0027] Specific examples of the coating apparatus and coating method according to the embodiment will be described below.

[0028] For example, a solar cell can be formed by coating using the coating apparatus 200. In one example, the number of pumps is 1. A pipe connected to one pump is split into two and connected to a coating head.

[0029] For example, the substrate 104 is a roll of PET film. The width of the PET film is, for example, 330 mm. A light-transmitting electrode having a width of 300 mm is formed on the PET film using a roll-to-roll sputtering device. The sheet resistance of the electrode is, for example, 10 Ω / □. The electrode has, for example, a laminated structure of ITO film / Ag alloy / ITO film. For example, multiple electrodes are provided. The length of each of the multiple electrodes is, for example, approximately 10 mm. The spacing between the multiple electrodes is, for example, 50 μm.

[0030] The coating head 100 described in embodiment 1 is prepared. The width of the slit of the coating head 10 is 0.5 mm at the ends and 1.0 mm at the center. The cross section of the outer surface 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).

[0031] In one example, a 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.

[0032] For example, the relative positional relationship between the coating head and the substrate is controlled by a gap ring or an actuator.

[0033] While the substrate is being transported, the coating liquid 102 is continuously supplied by the liquid supply pump 107. The moving speed of the substrate 104 is, for example, 5 m / min. The drying member 114 blows heated dry air onto the applied coating liquid 102. A solidified coating film is obtained from the coating liquid.

[0034] In an embodiment, after the above coating, another coating liquid may be further applied. The other coating liquid may include, for example, a semiconductor material. For example, the other coating liquid may include 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 C71 butyric acid methyl ester). PTB7 is, for example, a p-type semiconductor. PC70BM is, for example, an n-type semiconductor. The other coating liquid may further include, for example, monochlorobenzene. The amount of PTB7 per 1 mL of monochlorobenzene is 8 mg. The amount of PC70BM per 1 mL of monochlorobenzene is 12 mg. Another coating liquid 22A is a dispersion containing an organic semiconductor.

[0035] The other coating liquid is used to form, for example, a semiconductor film for a solar cell. When applying the other coating liquid, 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 application, the coating liquid is dried by a drying member.

[0036] For example, there are organic thin-film solar cells using organic semiconductors, or organic / inorganic hybrid solar cells. These solar cells can be produced using a coating method to create high-performance solar cells.

[0037] In an embodiment, the coating liquid may be applied to the substrate at a position where the substrate 104 is transported vertically, thereby, for example, applying the effect of gravity to the meniscus, making it easier to obtain a uniform film even at high speeds.

[0038] According to the embodiment, a coating device and a coating method capable of forming a uniform coating film are provided.

[0039] The embodiments of the present invention have been described above with reference to specific examples. However, the present invention is not limited to these specific examples. For example, the specific configurations of the elements included in the coating device, such as the pipe, pump, nozzle, and holder, are within the scope of the present invention as long as a person skilled in the art can implement the present invention in a similar manner and obtain similar effects by appropriately selecting them from known ranges.

[0040] Furthermore, any combination of two or more elements of each specific example within the scope of technical feasibility is also included within the scope of the present invention as long as it includes the gist of the present invention.

[0041] In addition, all coating devices and coating methods that can be implemented by a person skilled in the art by appropriately modifying the design based on the coating head, coating device, and coating method described above as embodiments of the present invention also fall within the scope of the present invention, as long as they include the gist of the present invention.

[0042] In addition, within the scope of the concept of the present invention, a person skilled in the art may come up with various modifications and alterations, and it will be understood that these modifications and alterations also fall within the scope of the present invention.

[0043] Although several embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims. [Explanation of symbols]

[0044] 100...Application head 101...Slit 102...Coating liquid 103...supply port 104...Base material 105...Coating film 106...Plumbing 107... Coating liquid supply member 108... Coating liquid tank 109...Outer surface 110...Substrate conveying member 111...Flow path 112...Manifold 113... Application head position member 114...Drying member 200... Coating device

Claims

1. A coating head used for slit coating that ejects a coating liquid from a slit, The coating head includes a manifold for temporarily storing a coating liquid therein; a slit for discharging the coating liquid stored in the manifold; a plurality of coating liquid supply ports for introducing coating liquids into the manifold; the manifold has a columnar shape and is disposed inside the coating head so as to be substantially parallel to the longitudinal direction thereof; the plurality of coating liquid supply ports are arranged at both ends of the manifold in the longitudinal direction, A coating head in which the gap at the longitudinal center of the slit is wider than the gap at the longitudinal ends.

2. (delete)

3. The coating head according to claim 1 , further comprising a coating liquid supply port for introducing the coating liquid into the central portion of the manifold.

4. The coating head according to claim 1 or 3, wherein the inner surface of the slit has an uneven structure.

5. The coating head according to claim 1 or 3, wherein an outer surface of the coating head from which the slit is exposed is a curved surface.

6. The coating head according to claim 1 or 3, wherein an outer surface of the coating head from which the slit is exposed is flat.

7. A coating device for supplying a coating liquid to a surface of a substrate and forming a coating film by slit coating, A coating head; a substrate transport member that transports the substrate; a coating liquid supply member that supplies the coating liquid to the coating head; Equipped with The coating head includes: a manifold for temporarily storing the coating liquid therein; a slit for discharging the coating liquid stored in the manifold; a plurality of coating liquid supply ports for introducing coating liquids into the manifold; the manifold has a columnar shape and is disposed inside the coating head so as to be substantially parallel to the longitudinal direction thereof; the plurality of coating liquid supply ports are arranged at both ends of the manifold in the longitudinal direction, The coating device, wherein the gap at the center of the slit in the longitudinal direction is wider than the gap at the ends in the longitudinal direction.

8. The coating device according to claim 7, further comprising 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 single coating liquid supply member.

10. A coating method for applying a coating liquid to a substrate by slit coating using a coating head, comprising: The coating head a manifold for temporarily storing the coating liquid therein; a slit for discharging the coating liquid stored in the manifold; a plurality of coating liquid supply ports for introducing coating liquids into the manifold; Equipped with the manifold has a columnar shape and is disposed inside the coating head so as to be substantially parallel to the longitudinal direction thereof; the plurality of coating liquid supply ports are arranged at both ends of the manifold in the longitudinal direction, The gap at the center of the slit in the longitudinal direction is wider than the gap at the end of the slit in the longitudinal direction, a coating method in which coating is performed by supplying a coating liquid to the plurality of coating liquid supply ports.

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

Images