Air knife device for coating and coating system

Abstract

The utility model discloses an air knife device for coating and a coating system, the air knife device for coating comprises an air knife body, the air knife body comprises a first air knife plate and a second air knife plate which are oppositely arranged, an air outlet slit is formed between the bottom end of the first air knife plate and the bottom end of the second air knife plate, and the air outlet slit is communicated with the first air knife plate and the second air knife plate. The air outlet direction of the air outlet slit is opposite to the top end of the air knife body; an air cavity is formed in the first air knife plate, an air inlet communicated with the air cavity is further formed in the first air knife plate, and the air cavity is communicated with the air outlet slit; a water flow channel is arranged in the second air knife plate, and a water inlet and a water outlet which are communicated with the two ends of the water flow channel respectively are further formed in the second air knife plate. The temperature of the air in the air cavity and the air outlet slit which are arranged adjacent to the air outlet slit can be reduced / increased, and then the temperature of the blowing air coming out of the air outlet slit can be adjusted according to needs.

Description

Technical Field

[0001] The utility model relates to the technical field of coating, in particular to an air knife device for coating and a coating system. Background Art

[0002] The air knife's principle is to create a high-speed, knife-like airflow by passing uneven pressure and flow of nitrogen or air through it, creating a more rapid and uniform airflow. Air knives are often used to remove moisture, dust, and oil from product surfaces and to dissipate heat. Air knife designs vary across industries and equipment.

[0003] An existing wind knife device for coating includes two wind knife plates arranged opposite to each other and fixed together, with an air outlet slit between the two wind knife plates. An air inlet is opened on one wind knife plate, and high-pressure gas can be injected into the air outlet slit through the air inlet. The high-pressure gas flows out from the air outlet slit to blow the surface to be blown.

[0004] The shortcoming of this type of air knife device for coating is that the temperature of the purge gas coming out of the air outlet slit is constant, but the temperature of the purge gas flowing out of the air outlet slit is different in different usage scenarios. Taking the coating of perovskite wet film through the air outlet slit as an example, the temperature requirements for the environment during the coating process are relatively strict. At high temperatures, the evaporation rate of the solvent increases, resulting in a decrease in residual solvent, thereby increasing the probability of nuclear aggregation, which has an adverse effect on the formation of the thin film. In a relatively low temperature environment, it is beneficial to improve the morphology of the thin film and improve the photoelectric conversion efficiency of the prepared device.

[0005] Therefore, it is very necessary to improve the above-mentioned coating air knife device to overcome the above-mentioned shortcomings. Utility Model Content

[0006] Therefore, the technical problem to be solved by the present invention is that in the existing air knife device for coating, the temperature of the purge air flow coming out of the air outlet slit is constant and cannot be adjusted according to actual needs, thereby providing a wind knife device for coating and a coating system.

[0007] In order to solve the above technical problems, the technical solutions of the present utility model are as follows:

[0008] A coating air knife device includes an air knife body, the air knife body including a first air knife plate and a second air knife plate arranged opposite to each other, an air outlet slit formed between the bottom ends of the first air knife plate and the bottom ends of the second air knife plate, and the air outlet direction of the air outlet slit is away from the top end of the air knife body;

[0009] The first wind blade plate has an air cavity therein, and an air inlet connected to the air cavity is also opened on the first wind blade plate, and the air cavity is connected to the air outlet slit;

[0010] The second wind blade plate has a water flow channel therein, and is also provided with a water inlet and a water outlet respectively connected to the two ends of the water flow channel.

[0011] Furthermore, the thickness of the second air blade plate is L1, and the thickness of the channel wall of the water flow channel facing the first air blade plate is L2, and L2 is less than or equal to 0.5L1.

[0012] Furthermore, L1 is 0.8 cm to 1.2 cm, and L2 is 0.4 cm to 0.6 cm.

[0013] Furthermore, the water flow channel is S-shaped or M-shaped.

[0014] Furthermore, the first air blade and / or the second air blade is a heat conducting member.

[0015] Furthermore, the air cavity is formed by partially inwardly recessing the side wall from the first air blade plate toward the second air blade plate, and the air cavity is laterally connected to the air outlet slit.

[0016] Furthermore, the air inlet leads to the top of the air cavity.

[0017] Furthermore, the coating air knife device further comprises an air knife frame, the air knife frame comprises two sub-air knife frames respectively arranged at the two ends of the air knife body, the sub-air knife frames comprising a transverse connecting structure, a vertical supporting structure and a locking member;

[0018] One end of the transverse connecting structure is connected to one end of the wind knife body, and the other end is connected to the vertical supporting structure through the locking member;

[0019] The locking member has a locked state and an unlocked state. In the locked state, the locking member locks the transverse connecting structure on the vertical supporting structure. In the unlocked state, the transverse connecting structure can drive the wind knife body to move vertically relative to the vertical supporting structure.

[0020] Furthermore, the vertical support structure includes a vertical support rod, a mounting frame and a mounting base connected in sequence, the locking member is connected to the vertical support rod, and the mounting base is a movable member.

[0021] The technical solution of this utility model has the following advantages:

[0022] 1. The coating air knife device provided by the utility model has a water flow channel in the second air knife plate, and a water inlet and a water outlet respectively connected to the water flow channel are opened on the second air knife plate. Cold water / hot water can enter the water flow channel from the water inlet and then flow out from the water outlet. The cold water / hot water continuously flowing in the water flow channel can reduce / increase the temperature of the second air knife plate. When the temperature of the second air knife plate is reduced / increased, the temperature of the gas in the wind cavity and the air outlet slit arranged adjacent thereto can be reduced / increased accordingly, thereby adjusting the purge gas flowing out of the air outlet slit. The temperature of the body can be adjusted to meet different needs, and ultimately improve the adaptability of the coating air knife device. For example, for slit coating of perovskite wet film, the environmental temperature requirements are relatively strict during the coating process. When the temperature of the purge gas is low, the evaporation rate of the solvent can be reduced, the amount of residual solvent can be ensured, and the probability of nuclear aggregation can be reduced, which is conducive to the formation of the film and improves the morphology of the film, and ultimately improves the photoelectric conversion efficiency of the prepared device. Of course, in some cases, such as when you want to improve the drying efficiency, you can pass hot water into the water flow channel.

[0023] 2. The coating air knife device provided by the present invention has a thickness of the second air knife plate of L1, and the thickness of the channel wall of the water flow channel facing the first air knife plate is L2, and L2 is less than or equal to 0.5L1. Such a design can take into account both the strength of the channel wall of the water flow channel and the cold / heat conduction efficiency.

[0024] 3. In the coating air knife device provided by the present invention, the second air knife plate is a heat conductor, which can further improve the cold / heat conduction efficiency.

[0025] 4. The utility model provides a wind knife device for coating, in which an air cavity is formed by a partial inward depression from the side wall of the first wind knife plate toward the second wind knife plate, and the air cavity is laterally connected to the air outlet slit between the first wind knife plate and the second wind knife plate. Such a design allows the gas in the air cavity and the air outlet slit to contact the second wind knife plate, thereby improving the cooling / heating efficiency of the gas by the second wind knife plate into which cold water / hot water is passed.

[0026] 5. The coating air knife device provided by the utility model has an air inlet leading to the top of the air cavity. In this way, the gas in the middle and lower parts of the air cavity can be forced to be discharged toward the air outlet slit by the high-pressure airflow entering the top of the air cavity from the air inlet, thereby reducing the disturbance of the airflow in the air cavity, ensuring the blowing force and stabilizing the blowing force.

[0027] 6. The wind knife device for coating provided by the utility model has a locking state and an unlocking state. In the locked state, the locking part locks the horizontal connecting structure on the vertical supporting structure to ensure the distance between the air outlet slit and the surface to be blown. In the unlocked state, the horizontal connecting structure can drive the wind knife body to move vertically relative to the vertical supporting structure, thereby adjusting the distance between the wind knife body and the surface to be blown, and ultimately improving the adaptability of the wind knife device for coating.

[0028] 7. The coating air knife device provided by the utility model has a vertical support structure including a vertical support rod, a mounting frame and a mounting base connected in sequence. The locking part is connected to the vertical support rod, and the mounting base is a movable part, so that the position of the entire coating air knife device can be changed as needed, thereby further improving the adaptability of the coating air knife device.

[0029] A coating system comprises the aforementioned coating air knife device and a coating device, wherein the coating device comprises a substrate for placing the workpiece to be coated, and a coating die head spaced above the substrate. In the moving direction of the workpiece to be coated, the air knife body of the coating air knife device is located in front of the coating die head, and the air outlet slit on the air knife body faces the top surface of the workpiece to be coated.

[0030] The technical solution of this utility model has the following advantages:

[0031] The utility model provides a coating system which has all the advantages of the aforementioned air knife device for coating. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] In order to more clearly illustrate the specific implementation methods of the utility model or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0033] Figure 1 Schematic diagram of the structure of the coating system in the embodiment of the present utility model;

[0034] Figure 2 This is a schematic structural diagram of an air knife device for coating in an embodiment of the present utility model;

[0035] Figure 3 Schematic diagram of the water flow channel in the second air blade in an embodiment of the present invention;

[0036] Figure 4 This is a front view of the air knife body in an embodiment of the present utility model;

[0037] Figure 5 This is a side view of the air knife body in an embodiment of the present utility model;

[0038] Figure 6 It is a schematic top view of the air knife body in an embodiment of the present utility model.

[0039] Description of reference numerals:

[0040] A. Coating device; A1. Coating die head; B. Coating air knife device; C. Substrate; D. Part to be coated; E. Air outlet slit;

[0041] 1. Wind knife body; 11. First wind knife plate; 111. Wind cavity; 112. Air inlet; 12. Second wind knife plate; 121. Water flow channel; 122. Water inlet; 123. Water outlet; 124. Pagoda water nozzle; 2. Wind knife frame; 21. Horizontal connecting structure; 211. End plate; 212. Connecting piece; 213. Sliding block; 22. Vertical supporting structure; 220. Vertical supporting rod; 221. Mounting frame; 222. Mounting base; 23. Locking piece; 3. Bolt. DETAILED DESCRIPTION

[0042] The following is a clear and complete description of the technical solution of the present invention in conjunction with the accompanying drawings. Obviously, the embodiments described are only some of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0043] In the description of this utility model, it should be noted that the terms "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings and are intended solely to facilitate the description of this utility model and simplify the description. They do not indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on this utility model. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0044] In the description of this utility model, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections, electrical connections; direct connections, indirect connections through an intermediate medium, and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on the specific circumstances.

[0045] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0046] Example 1

[0047] like Figures 1 to 6 As shown, this embodiment provides a coating air knife device B, including an air knife body 1, an air knife body 1 (such as Figure 2 and Figure 5 As shown) includes a first wind blade plate 11 and a second wind blade plate 12 arranged opposite to each other, and an air outlet slit E is formed between the bottom end of the first wind blade plate 11 and the bottom end of the second wind blade plate 12, and the air outlet direction of the air outlet slit E is away from the top of the wind blade body 1, and the first wind blade plate 11 has an air cavity 111 (as shown) Figure 5 As shown), the first air blade plate 11 is also provided with an air inlet 112 connected to the air cavity 111 (as shown Figure 5 As shown), the air cavity 111 is connected to the air outlet slit E, and the second air blade plate 12 has a water flow channel 121 (as shown Figure 3 As shown), the second air blade plate 12 is further provided with water inlets 122 (as shown) which are connected to the water flow channels 121. Figure 5 As shown) and the water outlet 123 (as shown Figure 5 shown).

[0048] The utility model provides a coating air knife device B, since the second air knife plate 12 has a water flow channel 121, the second air knife plate 12 is also provided with a water inlet 122 and a water outlet 123 respectively connected to the water flow channel 121, and cold water / hot water can enter the water flow channel 121 from the water inlet 122 and then flow out from the water outlet 123. The cold water / hot water continuously flowing in the water flow channel 121 can reduce / increase the temperature of the second air knife plate 12. When the temperature of the second air knife plate 12 is reduced / increased, the temperature of the gas in the wind cavity 111 and the air outlet slit E arranged adjacent thereto can be reduced / increased accordingly, thereby The temperature of the purge gas flowing out of the air outlet slit E can be adjusted to meet different needs, and ultimately improve the adaptability of the coating air knife device B. For example, for slit coating of perovskite wet film, the ambient temperature requirements are relatively strict during the coating process. When the temperature of the purge gas is low, the evaporation rate of the solvent can be reduced, the amount of residual solvent can be ensured, and the probability of nuclear aggregation can be reduced, which is beneficial to the formation of the film and improves the morphology of the film, and ultimately improves the photoelectric conversion efficiency of the prepared device. Of course, in some cases, such as when you want to improve the drying efficiency, you can pass hot water into the water flow channel 121.

[0049] In this embodiment, the water inlet 122 and the water outlet 123 are respectively connected to a pagoda water nozzle 124.

[0050] Furthermore, if Figure 5As shown, the thickness of the second air blade plate 12 is L1, and the wall thickness of the channel wall of the water flow channel 121 facing the first air blade plate 11 is L2, and L2 is less than or equal to 0.5L1. This design can take into account both the strength of the channel wall of the water flow channel 121 and the heat conduction efficiency. Specifically, L1 is 0.8 cm to 1.2 cm, preferably 1 cm, and L2 is 0.4 cm to 0.6 cm, preferably 0.5 cm. In this embodiment, the thickness of the first air blade plate 11 is the same as that of the second air blade plate 12.

[0051] Furthermore, if Figure 3 As shown, the water flow channel 121 is S-shaped. Of course, the water flow channel 121 can also be M-shaped. Such a design can increase the length of the water flow channel 121 in the second air blade 12, thereby improving the cooling / heating effect of the water flow on the second air blade 12. Specifically, the second air blade 12 is a heat conductor, and preferably, the first air blade 11 is also a heat conductor. In this way, the cold / heat conduction efficiency can be further improved.

[0052] In this embodiment, the air cavity 111 is a rectangular parallelepiped structure, and the length direction of the air cavity 111 is parallel to the length direction of the first air blade 11. Figure 5 As shown, the air cavity 111 is formed by partially inwardly recessing the side wall of the first air blade plate 11 toward the second air blade plate 12, so that both ends of the air cavity 111 in the longitudinal direction are closed. The air cavity 111 is laterally connected to the aforementioned air outlet slit E. This design allows the air in the air cavity 111 and the air outlet slit E to directly contact the second air blade plate 12, thereby improving the cooling / heating efficiency of the second air blade plate 12 that has passed cold / hot water on the purge gas. In other embodiments, the side of the air cavity 111 facing the second air blade plate 12 is a closed side, and only the bottom of the air cavity 111 is downwardly connected to the air outlet slit E.

[0053] Preferably, if Figure 5 As shown, the air inlet 112 leads to the top of the wind cavity 111. In this way, the gas in the middle and lower parts of the wind cavity 111 can be forced to be discharged toward the air outlet slit E by the high-pressure airflow entering the top of the wind cavity 111 from the air inlet 112. On the one hand, the blowing force can be guaranteed, and on the other hand, the disturbance of the airflow in the wind cavity 111 can be reduced, thereby stabilizing the blowing force.

[0054] In this embodiment, if Figure 2 、 Figure 4 as well as Figure 6 As shown, the air knife body 1 is a rectangular parallelepiped. The first air knife plate 11 includes two air inlets 112, spaced apart along the length of the air knife body 1. These two air inlets 112 are connected to the two top ends of the ventilation cavity 111, respectively. Each air inlet 112 is sealed to an external air pipe (not shown). The air pipe is made of a flexible material.

[0055] In this embodiment, a U-shaped gasket (not shown) with its opening facing downward is sandwiched between the first air blade plate 11 and the second air blade plate 12, so that the aforementioned air outlet slit E is formed between the bottom ends of the first air blade plate 11 and the second air blade. Figure 2 、 Figure 4 and Figure 6 As shown, the first air blade plate 11 and the second air blade plate 12 are fixed together by means of a plurality of bolts 5 .

[0056] Further, if Figure 2 As shown, the coating air knife device B also includes an air knife frame 2, which includes two sub-air knife frames respectively arranged at the two ends of the air knife body 1. The sub-air knife frames include a transverse connecting structure 21, a vertical support structure 22, and a locking member 23. One end of the transverse connecting structure 21 is connected to one end of the air knife body 1, and the other end is connected to the vertical support structure 22 via the locking member 23. The locking member 23 has a locked state and an unlocked state. In the locked state, the locking member 23 locks the transverse connecting structure 21 to the vertical support structure 22 to ensure the distance between the air outlet slit E and the surface to be blown. In the unlocked state, the transverse connecting structure 21 can drive the air knife body 1 to move vertically relative to the vertical support structure 22, thereby adjusting the distance between the air outlet slit E and the surface to be blown, ultimately improving the adaptability of the coating air knife device B. In this embodiment, the locking member 23 is a knob.

[0057] Furthermore, the vertical support structure 22 includes a vertical support rod 220, a mounting frame 221 and a mounting base 222 connected in sequence. The locking member 23 is connected to the vertical support rod 220. The mounting base 222 is a movable member, and the position of the entire coating air knife device B along the length direction of the substrate C can be adjusted as needed, thereby further improving the adaptability of the coating air knife device B.

[0058] Furthermore, the transverse connecting structure 21 includes an end plate 211 , a connecting member 212 , and a sliding block 213 that are sequentially connected. When the locking member 23 is in an unlocked state, the sliding block 213 can slide along the vertical support rod 220 .

[0059] Example 2

[0060] like Figures 1 to 6 As shown, this embodiment provides a coating system, including the coating air knife device B in embodiment 1 and the coating device A (such as Figure 1 As shown), the coating device A includes a substrate C for placing the object D to be coated, and a coating die head A1 spaced above the substrate C. In the moving direction of the object D to be coated (as shown Figure 1 (As shown by the dotted arrow in the middle), the air knife body 1 of the coating air knife device B is located in front of the coating die head A1, and the air outlet slit E on the air knife body 1 faces the top surface of the object D to be coated.

[0061] The utility model provides a coating air knife device B, since the second air knife plate 12 has a water flow channel 121, the second air knife plate 12 is also provided with a water inlet 122 and a water outlet 123 respectively connected to the water flow channel 121, and cold water / hot water can enter the water flow channel 121 from the water inlet 122 and then flow out from the water outlet 123. The cold water / hot water continuously flowing in the water flow channel 121 can reduce / increase the temperature of the second air knife plate 12. When the temperature of the second air knife plate 12 is reduced / increased, the temperature of the gas in the wind cavity 111 and the air outlet slit E arranged adjacent thereto can be reduced / increased accordingly, thereby The temperature of the purge gas flowing out of the air outlet slit E can be adjusted to meet different needs, and ultimately improve the adaptability of the coating air knife device B. For example, for slit coating of perovskite wet film, the ambient temperature requirements are relatively strict during the coating process. When the temperature of the purge gas is low, the evaporation rate of the solvent can be reduced, the amount of residual solvent can be ensured, and the probability of nuclear aggregation can be reduced, which is beneficial to the formation of the film and improves the morphology of the film, and ultimately improves the photoelectric conversion efficiency of the prepared device. Of course, in some cases, such as when you want to improve the drying efficiency, you can pass hot water into the water flow channel 121.

[0062] Furthermore, the air knife body 1 in Example 1 is installed above the base plate C through the air knife frame 2 , and the two vertical support structures 22 of the air knife frame 2 are located on two opposite sides of the base plate C respectively.

[0063] Before use, the air knife body 1 is positioned at a suitable position along the length of the base plate C by moving the vertical support structure 22. The vertical spacing between the air knife body 1 and the base plate C is then adjusted by tightening the locking member 23. During use, air enters the air cavity 111 through the air inlet 112 and flows out through the air outlet slit E. Simultaneously, cold / hot water is injected into the water flow channel 121 through the water inlet 122 to lower / raise the temperature of the second air knife plate 12. This lowering / raising of the temperature of the second air knife plate 12 lowers / raises the temperature of the purge air discharged from the air outlet slit E, thereby regulating the air temperature to meet actual needs.

[0064] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will readily appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A coating air knife device, characterized in that: The invention comprises a wind knife body (1), wherein the wind knife body (1) comprises a first wind knife plate (11) and a second wind knife plate (12) arranged opposite to each other, an air outlet slit (E) is formed between the bottom end of the first wind knife plate (11) and the bottom end of the second wind knife plate (12), and the air outlet direction of the air outlet slit (E) is opposite to the top end of the wind knife body (1); The first wind blade plate (11) has a wind cavity (111) therein, and the first wind blade plate (11) is also provided with an air inlet (112) connected to the wind cavity (111), and the wind cavity (111) is connected to the air outlet slit (E); The second wind blade plate (12) has a water flow channel (121) therein, and the second wind blade plate (12) is also provided with a water inlet (122) and a water outlet (123) respectively connected to the two ends of the water flow channel (121).

2. The coating air knife device according to claim 1, characterized in that: The thickness of the second wind blade plate (12) is L1, and the thickness of the channel wall of the water flow channel (121) facing the first wind blade plate (11) is L2, and L2 is less than or equal to 0.5L1.

3. The coating air knife device according to claim 2, characterized in that: L1 is 0.8 cm to 1.2 cm, and L2 is 0.4 cm to 0.6 cm.

4. The coating air knife device according to claim 1, characterized in that: The water flow channel (121) is S-shaped or M-shaped.

5. The coating air knife device according to claim 1, characterized in that: The second air blade (12) is a heat conducting component.

6. The coating air knife device according to any one of claims 1 to 5, characterized in that: The air cavity (111) is formed by partially inwardly recessing the side wall of the first air blade plate (11) toward the second air blade plate (12), and the air cavity (111) is laterally connected to the air outlet slit (E).

7. The coating air knife device according to any one of claims 1 to 5, characterized in that: The air inlet (112) leads to the top end of the air cavity (111).

8. The coating air knife device according to any one of claims 1 to 5, characterized in that: The coating air knife device (B) further comprises an air knife frame (2), wherein the air knife frame (2) comprises two sub-air knife frames respectively arranged at the two ends of the air knife body (1), and the sub-air knife frames comprise a transverse connecting structure (21), a vertical supporting structure (22) and a locking member (23); One end of the transverse connecting structure (21) is connected to one end of the wind knife body (1), and the other end is connected to the vertical supporting structure (22) via the locking member (23); The locking member (23) has a locked state and an unlocked state. In the locked state, the locking member (23) locks the transverse connecting structure (21) on the vertical supporting structure (22). In the unlocked state, the transverse connecting structure (21) can drive the wind knife body (1) to move vertically relative to the vertical supporting structure (22).

9. The coating air knife device according to claim 8, characterized in that: The vertical support structure (22) comprises a vertical support rod (220), a mounting frame (221) and a mounting base (222) connected in sequence; the locking member (23) is connected to the vertical support rod (220); and the mounting base (222) is a movable member.

10. A coating system, characterized in that: The invention comprises a coating air knife device (B) and a coating device (A) according to any one of claims 1 to 9, wherein the coating device (A) comprises a substrate (C) for placing a workpiece (D) to be coated, and a coating die head (A1) spaced apart above the substrate (C); in the moving direction of the workpiece (D) to be coated, the air knife body (1) of the coating air knife device (B) is located in front of the coating die head (A1), and the air outlet slit (E) on the air knife body (1) faces the top surface of the workpiece (D) to be coated.

Images