Improved atomizer for plasma coating equipment

Abstract

The present invention relates to an aerosol generation device for generating a precursor-containing aerosol flow for a plasma coating process, the aerosol generation device comprising an aerosol droplet separator and a set of atomizing sections, the aerosol droplet separator comprising a nozzle outlet, a precursor recycle outlet and an aerosol channel therebetween, each atomizing section comprising: a fluid flow path comprising an atomizer gas inlet and an atomizer gas outlet fluidly connected to the aerosol channel; a precursor channel comprising a precursor channel inlet and a precursor channel outlet, the precursor channel outlet being a fluid flow path for introducing precursor droplets into a gas flow in the fluid flow path. a precursor reservoir for a liquid precursor, the precursor reservoir being fluidly connected to the precursor channel inlet; a droplet introduction means arranged at or near the precursor channel outlet for introducing liquid precursor droplets from the precursor reservoir via the precursor channel into the gas stream in the fluid flow path; and a dilution flow path separated from the fluid flow path, the dilution flow path comprising a dilution inlet and a dilution outlet fluidly connected to the aerosol channel, wherein for each spray section, the dilution outlet is arranged between the sprayer gas outlet and the nozzle outlet of the aerosol droplet separator.

Description

[Technical field]

[0001] The present invention relates to an improved atomizer for a plasma coating apparatus and to an improved method for atomizing a liquid for use in a plasma coating process.The present invention therefore relates to the field of atomizers and to the field of plasma coating methods and apparatus. [Background technology]

[0002] Plasma coating is a technique in which a coating is deposited on a substrate using precursors, which are excited to make them more reactive and therefore more easily form a high quality coating on the substrate. The excitation of the precursors is obtained directly or indirectly through the plasma process.

[0003] In a direct plasma coating process, a fluid containing the precursor is turned into a plasma, for example by flowing the fluid through a set of electrodes that drive a plasma into the fluid by application of a high voltage. In such a direct process, the precursor can be directly excited. The excited precursor can then be allowed to interact with a substrate, thereby forming a coating on the substrate.

[0004] In the indirect plasma coating process, a process fluid, preferably a process gas, is plasmatized, for example, by flowing the process fluid between a set of electrodes that can drive a plasma into the process fluid by applying a high voltage. The plasmatized process gas then leaves the plasma zone, i.e. the zone where the plasma is actively induced, for example the zone between a set of electrodes. A precursor-containing fluid is then mixed with the plasmatized process gas in the plasma afterglow. The precursors are then excited in this mixture due to secondary interactions with the plasmatized process gas, making the precursors more reactive to allow a coating to be formed on a substrate exposed to the mixture and the excited precursors in said mixture. Summary of the Invention [Problem to be solved by the invention]

[0005] The plasma coating process may be carried out at atmospheric or vacuum pressure. The present invention is particularly suitable for plasma coating processes at atmospheric pressure. In atmospheric pressure plasma coating processes, the substrate is subjected to a mixture containing said excited precursors at essentially atmospheric pressure. This has the particular advantage that there is no need for vacuum technology and the substrate can be treated continuously, for example by moving the substrate through the mixture and / or by flowing the mixture over the substrate. This is in conjunction with vacuum pressure plasma coating processes, where it is always cumbersome to ensure low pressure at the exposure position of the substrate to the mixture. Moreover, atmospheric pressure plasma coating processes have the further advantage that it tends to be easier to transport many different types of precursors to the plasma zone and / or plasma afterglow region.

[0006] The present invention is preferably located in the field of indirect atmospheric plasma coating processes. Moreover, the present invention is also preferably located in the field of low-temperature plasma coating processes, where the temperature of the plasma and the temperature of the mixture containing the excited precursor are usually below 200 ° C, preferably around room temperature. This already sets severe constraints on the method for transporting the precursor, and if the precursor is vaporized to be easily mixed with the plasmatized process gas, the mixture may have a high temperature, depending on several factors such as the vaporization temperature of the precursor and the flow rate of the process gas and the vaporized precursor. For many precursors, especially high-mass precursors, the vaporization temperature may be very high, and as a result, the temperature of the mixture is high. In such cases, the substrate may actually be affected by high temperatures, for example, certain polymer substrates may melt, deformations due to temperature gradients may occur, the coating may not adhere to the substrate after cooling, etc. To overcome this problem, the precursor can be transported in the form of an aerosol into the process gas.

[0007] Within the context of the present invention, an aerosol is a suspension of fine droplets in a gas. An aerosol behaves as a fluid. The diameter of the droplets can vary, but is usually about 1 μm or less. The process of suspending droplets in a gas stream is also called nebulization.

[0008] The present invention relates to an improved atomizer for atomizing liquid precursors for atmospheric pressure low temperature plasma coating processes, as well as an improved method of atomizing liquid precursors for said plasma coating processes.

[0009] An exemplary known atomizer is, for example, the Aerosol Generator Model 3076 manufactured by TSI Inc. This atomizer allows the generation of an aerosol using an aerosol gas stream capable of suspending droplets of liquid precursor from a reservoir using the Venturi effect. However, the inventors have found that such atomizers may not allow good control of droplet size, droplet concentration in the aerosol, and / or precursor concentration in the aerosol for further use in a plasma coating apparatus or plasma coating process. More specifically, the conditions in terms of flow rate, pressure gradient, temperature, etc., most efficient for generating an aerosol may not be compatible with the requirements of the aerosol for use in a further plasma coating apparatus or method.

[0010] Furthermore, in some plasma coating processes, it is preferable to use precursors that contain two or more different substances. In such cases, it may be difficult to control the absolute and / or relative abundance of the different substances in the aerosol. For example, if the liquid precursor in the reservoir contains two substances of equal concentration (i.e., 50% by weight of a first substance and 50% by weight of a second substance), this equal concentration may not be preserved in the aerosol, since the different substances may be atomized differently. Furthermore, the efficiency of atomization may be significantly reduced due to large differences in the optimal atomization parameters for the different substances.

[0011] To that end, the inventors have developed an improved atomizer and an improved atomization method for generating precursor-containing aerosols for indirect atmospheric pressure low-temperature plasma coating processes. The improved atomizer allows for good control over the precursor-containing aerosol flow and allows for easy modifications to the precursor-containing aerosol flow when its parameters must be modified, for example, for testing purposes or for rapid changes in the precursor-containing aerosol that may be required by the plasma coating process.

[0012] The nebulizer and nebulization method of the present invention further allows for better control over the amount of precursor in the resulting aerosol stream, particularly the size of the droplets, the concentration of the droplets, and / or the concentration of precursor in the resulting aerosol stream. The present invention also allows for easy scaling of the total amount of precursor and / or precursor droplets in the aerosol stream. Furthermore, the present invention also allows for the generation of precursor-containing aerosols whereby the precursor comprises two or more substances. [Means for solving the problem]

[0013] The present invention relates to an aerosol generating device for generating a precursor-containing aerosol flow for a plasma coating process, the aerosol generating device comprising an aerosol droplet separator and a set of spray compartments, the aerosol droplet separator comprises a nozzle outlet, a precursor recycle outlet, and an aerosol channel therebetween; Each spray section is a fluid flow path, preferably including a nebulizer gas inlet connected to a nebulizer gas source, and a nebulizer gas outlet fluidly connected to the aerosol channel; a precursor channel including a precursor channel inlet and a precursor channel outlet, the precursor channel outlet being fluidly connected to a fluid flow path for introducing precursor droplets into a gas flow in the fluid flow path; a precursor reservoir for liquid precursors, preferably comprising a liquid precursor, the precursor reservoir being in fluid connection with the precursor channel inlet; - droplet introduction means arranged at or near the precursor channel outlet for introducing liquid precursor droplets from a precursor reservoir through the precursor channel into the gas stream in the fluid flow path; a dilution flow path separate from the fluid flow path, the dilution flow path preferably including a dilution inlet connected to a dilution gas source, and a dilution outlet fluidly connected to the aerosol channel; Equipped with For each atomizing section, a dilution outlet is disposed between the atomizer gas outlet and the nozzle outlet of the aerosol droplet separator.

[0014] Preferably, the dilution flow path is oriented essentially parallel to the fluid flow path, and preferably, the aerosol channel is oriented essentially perpendicular to the fluid flow path and / or the dilution flow path.

[0015] The dilution flow channel allows for controlling the amount and / or size of droplets in the aerosol in a precise and stable manner, independent of how the precursor is introduced into the fluid flow channel. In many applications, the dilution outlet is placed relatively close to the nebulizer gas outlet to better control the amount and size of the droplets. Thus, in a preferred embodiment, the dilution outlet is placed within an outlet-to-outlet distance of 10 cm or less from the nebulizer gas outlet, such as 10 cm, 9 cm, 8 cm, 7 cm, 6 cm, 5 cm, 4 cm, 3 cm, 2 cm, 1 cm, or any value therebetween or below. Control over the amount and / or size of the droplets can be achieved via a hydrodynamic process. Thereby, the dilution flow can be controlled to hydrodynamically adjust the pressure, pressure gradient, and / or flow in the aerosol channel and accordingly adjust the size and / or amount of droplets in the aerosol flowing in the aerosol channel. This allows for greater freedom in the selection of parameters important for efficient atomization of the precursor in the gas stream in the fluid flow path, such as atomizer gas flow, atomizing gas pressure, atomizing gas temperature, precursor reservoir pressure, precursor reservoir temperature, etc. The dilution flow thus generates an aerosol flow that can be directed to the plasma coating device through a nozzle attached to the nozzle outlet of the aerosol droplet separator. The droplets that are not entrained in this aerosol flow can be removed from the aerosol channel through the precursor recycle outlet. This removal can be achieved by the dilution flow, preferably by gravity, i.e. in this case the precursor recycle outlet is located lower than the nozzle outlet so that the droplets that are not entrained in the aerosol flow can flow down along the walls of the aerosol channel where they can be recycled.

[0016] The droplet introduction means preferably comprises a Venturi tube arranged in the fluid flow passage at the location of the precursor channel outlet, which allows precursor droplets to be introduced into the atomizer gas stream due to the Venturi effect. For example, the fluid flow passage may comprise a narrowed cross section near and / or at the precursor channel outlet, i.e. where the precursor channel is fluidly connected to the fluid flow passage.

[0017] In one embodiment, the set of spray compartments includes one compartment. However, a particular advantage of the present invention is that the spray compartments can be easily parallelized. Indeed, in one embodiment, the set of spray compartments includes two or more spray compartments, such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 or more spray compartments. Multiple spray compartments can be arranged adjacent to each other, thereby forming a row of spray compartments. This allows the atomizer gas outlet of each of the set of spray compartments to be fluidly connected to the same aerosol channel. This allows the aerosol coming from multiple spray compartments to be guided together to the plasma coating device.

[0018] The parallelization of the spray compartments provides two important advantages. First, it allows for an increase in the total flow rate of the aerosol that can be delivered to the plasma coating apparatus. Second, it allows for the combination of flows from multiple spray compartments when multiple precursors are used, i.e., when a mixture of different precursors is provided to the plasma coating apparatus, multiple spray compartments connected in parallel to the aerosol channel allow for a continuous supply of an aerosol containing a combination of different precursors. Furthermore, because the spray components have separate fluid flow paths, the parameters of the fluid flow paths, such as the flow of plasma gas through the fluid flow paths, or the dimensions of the channels, can be selected and / or adjusted to efficiently spray a particular precursor in that spray compartment. Thus, in a preferred embodiment, each spray component includes an atomizer control system for controlling the spray parameters. The spray parameters are as follows: -Plasma gas flow through the fluid flow channel - temperature of plasma gas in the fluid flow path - the temperature of the precursor in the reservoir and / or in the precursor channel - pressure in the precursor reservoir and / or precursor channel may include any or all of the following:

[0019] This allows the parameters of the spray process in each spray zone to be controlled separately and therefore allows the spray process to be optimized separately for each spray zone and / or depending on the precursor demand required for the plasma coating apparatus.

[0020] Yet another advantage of the present invention is that a more uniform coating can be obtained even at high production rates. Due to the parallelization of the atomizers, a high flow of the precursor-containing aerosol stream can be provided to a nozzle with a large cross section. This high aerosol stream may then have enough time to become uniform in the nozzle before the stream is plasmatized. The separation of the spraying process and the transport to the plasma coating device also provides a high degree of freedom in choosing the cross section of the nozzle, which also helps in the design of nozzles for very different types of substrates and / or coating properties.

[0021] Additionally, by using nozzles with cross sections of varying widths and / or varying heights, density variations can be obtained for the precursors and / or droplets in the aerosol stream, allowing the substrate to be coated with varying compositions and / or thicknesses across the surface of the substrate. The variations may include variations in the concentration of precursors and / or the relative abundance of different precursors when more than one precursor is sprayed.

[0022] In a similar aspect, the present invention relates to an aerosol generation method for generating a precursor-containing aerosol stream for a plasma coating process, the method comprising: providing a flow of atomizer gas in the fluid flow path; - introducing droplets of a precursor from a precursor reservoir into said nebulizer gas stream, thereby generating a precursor-containing aerosol stream within a fluid flow path; - directing said aerosol stream into an aerosol channel via a fluid flow passage outlet; - directing a dilution flow into said aerosol channel via a dilution flow outlet, thereby hydrodynamically adjusting the size and / or amount of droplets in the aerosol flow, resulting in precursor residue separated from the aerosol flow; - directing the aerosol flow in the aerosol channel to a nozzle outlet and directing the precursor residue to a precursor recycle outlet; Includes.

[0023] Preferably, the precursor-containing aerosol stream is further directed to a plasma coating device via a nozzle attached to the nozzle outlet.

[0024] The invention also relates to a plasma coating system comprising an aerosol generation device according to the invention and a plasma coating apparatus, where an aerosol channel of the aerosol generation device is fluidly connected to a precursor input of the plasma coating apparatus by a nozzle connected between a nozzle outlet of the aerosol channel and a nozzle inlet of the plasma coating apparatus. Thus, the invention also relates to a method for plasma coating a substrate using the method described above, further comprising directing an aerosol flow from the aerosol channel to the plasma coating apparatus and plasma coating a substrate with said aerosol flow using the plasma coating apparatus.

[0025] Plasma coating apparatuses and plasma coating processes using precursor-containing aerosols are known in the art, for example from WO 2021123414 A1, EP 3881941 A1, WO 2019243631 A1, WO 2020099434 A1 and / or WO 2019038378 A1 in the name of the present applicant. [Brief description of the drawings]

[0026] [Figure 1] 1 shows an atomizer that uses the Venturi effect. [Figure 2A] The aerosol generating device (1) according to the invention is shown in cross-section. [Figure 2B] 1 shows a perspective view of the inside of a device according to the invention. [Figure 3A] 1 shows an aerosol generating device comprising a nozzle. [Figure 3B] 1 shows an aerosol generating device comprising a nozzle. [Figure 4] It is shown how the aerosol generating device can be coupled to a plasma coating apparatus (25) using a nozzle. [Figure 5A] 1 shows a possible embodiment of a plasma coating device that can be used. [Figure 5B] 1 shows a possible embodiment of a plasma coating device that can be used. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0027] FIG. 1 shows an atomizer using the Venturi effect. The illustrated atomizer (200) comprises an atomizer gas inlet (201) through which a gas, preferably a plasma gas, can flow. A reservoir containing a liquid material, preferably including a precursor, can be connected to the precursor inlet (202). The precursor inlet comprises a precursor channel (204) fluidly connected (203) to the gas inlet. The gas inlet preferably comprises a gas inlet channel (206) having a cross section including a constriction (205) near to the fluid connection (203) with the precursor channel (204). The constriction ensures a rapid gas flow, thereby ensuring a static negative pressure to create the Venturi effect. Thereby, small precursor droplets (207) and precursor molecules can essentially be sucked out of the reservoir due to the negative pressure, thereby forming part of the flow in the aerosol channel (211). A portion of the precursor droplets (208) can mix with the gas, thereby forming an aerosol, which can be transported (209) to the plasma zone or plasma afterglow. Another portion of the droplets may not mix with the gas and / or may condense (211), for example, against the walls in the aerosol channel, and may be transported to an excess liquid drain (210) where it may be recovered for further use.

[0028] Figure 2A shows in cross-section an aerosol generating device (1) according to the invention. The device comprises an aerosol droplet separator (2) and an atomizing section (3). The aerosol droplet separator comprises a nozzle outlet (4), a precursor recycle outlet (5) and an aerosol channel (6) between them.

[0029] The spray section (3) is a fluid flow path (7) preferably including a nebulizer gas inlet (8) connected to a nebulizer gas supply, and a nebulizer gas outlet (9) fluidly connected to the aerosol channel (6); - a precursor channel (10) comprising a precursor channel inlet (11) and a precursor channel outlet (12), the precursor channel outlet (12) being fluidly connected to a fluid flow path (7) for introducing precursor droplets into a gas stream in the fluid flow path; a precursor reservoir (13) for liquid precursors, preferably comprising a liquid precursor, the precursor reservoir (13) being in fluid connection with the precursor channel inlet (11); - droplet introduction means (14) arranged at or near the precursor channel outlet (12) for introducing liquid precursor droplets from a precursor reservoir (13) via the precursor channel (10) into the gas stream in the fluid flow path, the droplet introduction means (14) preferably comprising a Venturi (15) arranged in the fluid flow path (7) at the location of the precursor channel outlet (12); a dilution flow path (16) separate from the fluid flow path (7), the dilution flow path (16) preferably comprising a dilution inlet (17) connected to a dilution gas source, and a dilution outlet (18) fluidly connected to the aerosol channel (6); Equipped with.

[0030] Thereby, the dilution outlet is located between the nebulizer gas outlet (9) and the nozzle outlet (4) of the aerosol droplet separator (2).

[0031] It should be noted that due to the cross-sectional view of Figure 2A, other spray sections are not shown, but may be present in a direction perpendicular to the plane of the cross-section, i.e., the spray section (3) shown in Figure 2A, and may be repeated multiple times in a direction perpendicular to the plane of the cross-section, whereby the aerosol droplet separator preferably comprises an essentially constant cross-section in a direction perpendicular to the plane of the cross-section shown, i.e., the spray section may be repeated multiple times with separate fluid flow paths, separate dilution channels, separate precursor channels, and / or separate precursor reservoirs, and the aerosol channel preferably extends across all the spray sections.

[0032] To illustrate the above, FIG. 2B shows a perspective view of the inside of a device according to the invention, with a set of 20 paralleled spray compartments. Thereby, the device is cut through the aerosol channel (6) and shows the diluent outlets (18a, 18b, 18c, 18d), the fluid flow outlets (9a, 9b, 9c, 9d), and the precursor channels (10a, 10b, 10c, 10d) of the spray compartments. It should be noted that only four of the diluent outlets, fluid flow outlets, and precursor channels are referenced so that the figure is not cluttered with too many references. The figure also shows a precursor reservoir (13), which in the illustrated embodiment is a common precursor reservoir for all spray compartments, i.e. the precursor reservoirs or spray compartments are fluidly connected. It should also be noted that the aerosol channel (6) is a single aerosol channel for all spray compartments in the embodiment of FIG. 2B. The embodiment shown in FIG. 2B is particularly preferred when parallelization is primarily used to increase the total flow rate of precursor-containing aerosol that can be generated for the plasma coating process and a single precursor fluid is used; the aerosols from the different spray compartments are then allowed to mix in the aerosol channel, allowing for collective recovery of precursor droplets.

[0033] However, it should be noted that in other embodiments, further compartmentalization may occur. For example, the aerosol channel may be compartmentalized, for example, the aerosol channel may include two or more separate sections for two or more subsets of the spraying compartments, preferably the aerosol channel includes a separate section for each of the spraying compartments. Preferably, the separate section extends up from the fluid flow passage outlet to the nozzle outlet. Additionally or alternatively, the separate section may extend down from the fluid flow passage outlet to the precursor recycling outlet. The separate section allows the precursor streams for different spraying compartments to be kept separate until they are up to the nozzle and / or recycled, which may be important, for example, when different precursors are used in different spraying compartments.

[0034] Compartmentalization can also be used to better control the spray process within the spray compartment.

[0035] In one embodiment, the precursor reservoirs of two or more spraying compartments may be fluidly connected. In a preferred embodiment, the precursor reservoirs of the spraying compartments are divided into two or more subsets of precursor reservoirs, for example 2, 3, 4, 5 or more subsets, and the precursor reservoirs of each subset are fluidly connected to each other. This is particularly preferred when using two or more different precursors or precursor mixtures. This is also particularly preferred in combination with a compartmentalized aerosol channel as described herein above.

[0036] In one embodiment, the aerosol channel includes a flow-inducing fan to assist the flow within the aerosol channel and / or to aid in the selection of droplet size and / or droplet volume within the aerosol.

[0037] In one embodiment, the aerosol generating device comprises a nozzle attached to the nozzle outlet. Preferably, the nozzle is detachably attached to allow easy maintenance and replacement. The nozzle may comprise two or more sections for directing the precursor-containing aerosol stream from the nozzle outlet to the plasma coating device, said two or more sections in the nozzle preferably corresponding to sections in the aerosol channel. In one embodiment, the nozzle comprises separate sections for each of the spraying compartments, preferably in combination with an aerosol channel comprising separate sections for each of the spraying compartments extending at least from the fluid flow channel outlet to the nozzle outlet. This makes it possible to keep the aerosol streams from each compartment to the plasma coating device separate. Such compartmentalization of the nozzle may also be used to better control the droplet orientation and / or the aerosol stream.

[0038] In general, all of the forms of compartmentalization provided above make it possible to have different injection rates of different precursors and better control of the resulting droplet mixture of precursors within the aerosol provided to the plasma coating apparatus.

[0039] Figures 3A and 3B show an aerosol generating device comprising the nozzle (20) described above. The figures show how the device may preferably comprise a body (21) containing the aerosol droplet separator (2) and a manifold (22) containing the dilution flow path (16), the fluid flow path (7), the droplet introduction means (14) and optionally a part of the precursor channels of a set of spray sections. The manifold may be attached to the body, preferably removably attached, for example by bolts or screws. The device may also comprise a reservoir piece (23) containing at least a part of the precursor reservoir (13) and the precursor channel (10). The reservoir piece is attached to the body, preferably removably attached, and optionally has a spacer part (24) between the body and the reservoir piece, which allows the distance between the reservoir piece and the body to be adjusted.

[0040] Figure 4 shows how the aerosol generating device (1) can be coupled to a plasma coating apparatus (25) using a nozzle. Figures 5A and 5B show two possible embodiments (25A, 25B) of a plasma coating device that can be used. Thereby, the plasma coating apparatus comprises an aerosol inlet (26A, 26B) of an aerosol duct (27A, 27B) to which the nozzle of Figure 4 can be coupled. The plasma coating apparatus preferably comprises a plasma duct (28A, 28B) through which a plasma gas can flow (the flow goes from top to bottom in the figure, but the direction can be changed). The plasma gas can be ignited, whereby a plasma is formed in the plasma duct. Ignition can be achieved by a pair of electrodes (29A, 29B) preferably separated from the plasma duct by a dielectric (30A, 30B). The aerosol is then injected (31A, 31B) into the plasma, preferably into the plasma afterglow (32A, 32B), which is a region where the plasma is not directly induced but which further contains excited species such as ionized molecules or radicals obtained directly or indirectly from the plasma or from interactions between the plasma and the aerosol. A precursor-containing plasma is thus formed, which can be used to coat, for example, a substrate (34A, 34B) which can be moved (33A, 33B) under the flow of the precursor-containing plasma.

Claims

1. 1. An aerosol generating device for generating a precursor-containing aerosol flow for a plasma coating process, the aerosol generating device comprising an aerosol droplet separator and a set of spray compartments, the aerosol droplet separator comprises a nozzle outlet, a precursor recycle outlet, and an aerosol channel therebetween; Each spray section is a fluid flow path including a nebulizer gas inlet and a nebulizer gas outlet fluidly connected to said aerosol channel; a precursor channel including a precursor channel inlet and a precursor channel outlet, said precursor channel outlet being fluidly connected to said fluid flow path for introducing precursor droplets into a gas flow in said fluid flow path; a precursor reservoir for a liquid precursor, said precursor reservoir being in fluid connection with said precursor channel inlet; - droplet introduction means arranged at or near the precursor channel outlet for introducing liquid precursor droplets from the precursor reservoir through the precursor channel into the gas stream in the fluid flow path; a dilution flow path separate from the fluid flow path, the dilution flow path including a dilution inlet and a dilution outlet fluidly connected to the aerosol channel; Equipped with An aerosol generating device, wherein for each atomizing section, the dilution outlet is disposed between the atomizer gas outlet and the nozzle outlet of the aerosol droplet separator.

2. The aerosol generating device of claim 1 , wherein the dilution flow path is oriented essentially parallel to the fluid flow path.

3. 10. The aerosol generating device according to any of the preceding claims, wherein the aerosol channel is oriented essentially perpendicular to the fluid flow path and / or the dilution flow path.

4. 10. The aerosol generating device of any preceding claim, wherein the dilution outlet is positioned within an outlet distance of 10 cm or less from the nebulizer gas outlet, such as 10 cm, 9 cm, 8 cm, 7 cm, 6 cm, 5 cm, 4 cm, 3 cm, 2 cm, 1 cm, or any value therebetween or below.

5. 10. The aerosol generating device according to any of the preceding claims, wherein the nebulizer gas inlet is connected to a nebulizer gas source, the dilution inlet is connected to a dilution gas source, and / or the precursor reservoir contains a liquid precursor.

6. 10. The aerosol generation device according to any of the preceding claims, wherein the droplet introduction means comprises a Venturi tube arranged in the fluid flow passage at the location of the precursor channel outlet.

7. 10. The aerosol generation device of any preceding claim, wherein the set of atomizing compartments includes two or more atomizing compartments, and the atomizer gas outlet of each of the set of atomizing compartments is fluidly connected to the aerosol channel.

8. The aerosol generation device according to claim 7 , wherein the plurality of spray compartments are arranged adjacent to each other, thereby forming an array of spray compartments.

9. Each atomization component includes an atomizer control system for controlling atomization parameters, the atomization parameters being: - a flow of plasma gas through said fluid flow passage the temperature of the plasma gas in the fluid flow passage; the temperature of the precursor in the reservoir and / or in the precursor channel the pressure in said precursor reservoirs and / or precursor channels 13. An aerosol generating device as claimed in any preceding claim, comprising any or all of the following:

10. 13. The aerosol generating device according to any of the preceding claims, wherein the aerosol channel is compartmentalized and / or the precursor reservoirs of two or more spray compartments are fluidly connected.

11. 10. The aerosol generating device of any preceding claim, wherein the aerosol channel is provided with a flow-inducing fan to assist the flow within the aerosol channel and / or to aid in the selection of droplet size and / or droplet volume within the aerosol.

12. 10. The aerosol generating device according to any of the preceding claims, wherein the aerosol generating device comprises a nozzle attached to the nozzle outlet.

13. A plasma coating system comprising an aerosol generating device according to any of the preceding claims and a plasma coating apparatus, wherein the aerosol channel of the aerosol generating device is fluidly connected to a precursor input of the plasma coating apparatus.

14. 1. An aerosol generation method for generating a precursor-containing aerosol stream for a plasma coating process, the method comprising: - providing a flow of atomizer gas in the fluid flow path; - injecting droplets of a precursor from a precursor reservoir into said nebulizer gas stream, thereby generating a precursor-containing aerosol stream within said fluid flow path; - directing said aerosol stream into an aerosol channel via a fluid flow passage outlet; - directing a dilution flow into the aerosol channel via a dilution outlet, thereby hydrodynamically adjusting the size and / or amount of droplets in the aerosol flow, resulting in precursor residues separated from the aerosol flow; - directing the aerosol flow in the aerosol channel to a nozzle outlet and directing the precursor residue to a precursor recycle outlet; 13. A method for generating an aerosol comprising:

15. 15. The aerosol generating method of claim 14, wherein the precursor-containing aerosol stream is directed to a plasma coating device through a nozzle.

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