KR20190080273A - Manufacturing method of micro nozzle array using mold and electrostatic spray system - Google Patents

Abstract

The present invention provides an electrostatic spray system. The electrostatic spray system comprises a nozzle part for injecting fluid droplets; an electrode part spaced apart from the nozzle part; a power supply part for forming a voltage between the fluid sprayed through the nozzle part and the electrode part; and a power control part for changing the direction of a voltage formed between the fluid and the electrode part. It is possible to produce a micro nozzle array with high yield.

Description

TECHNICAL FIELD [0001] The present invention relates to a method of manufacturing a micro-nozzle array using a mold and an electrostatic spraying system,

The present invention relates to a method of fabricating a micro-nozzle array capable of electrostatic spraying of water using a MEMS technology, and a method of manufacturing the same.

The present invention relates to techniques for indoor air cleaning and humidification, and more specifically to techniques for spraying and controlling water nano-droplets using electrostatic spraying. Unlike a filter type air cleaning system which is widely used in industry, the present invention is applied to an electrostatic atomizing air cleaning humidifying system capable of sterilizing fine dust collecting and airborne bacteria by using charged water droplet characteristics. The electrostatic spray air cleaning humidification system does not use a filter, so it can be efficiently cleaned without problems such as periodical replacement, noise, energy loss, and secondary harmful substances. However, it is difficult to spray water electrostatically, Difficulty in spraying, difficulty in control of water droplets, and thus it was difficult to effectively implement a common air cleaning system.

Since water (Deionized water standard) has higher electrical conductivity (120 μS / m) and surface tension (0.072 N / m) than other fluids, stable electrostatic spray is limited with general spray nozzles. There is a high possibility of involving. It is known that a non-conductive / hydrophobic nozzle having a small diameter of several tens of micrometers is required for stable electrostatic spraying. However, there is a problem that the manufacturing process is difficult and the nozzle is small and the amount of droplet spraying is reduced. Studies have been attempted to overcome the problem of spray volume by arranging multiple nozzles, but very successful cases are very rare because very high precision is required for each nozzle shape and arrangement for a uniform electric field distribution.

 The water droplets generated through electrostatic spraying have a great advantage in the field of air cleaning in that they have charge through the ionization process. It is known that the droplet of the same polarity is sprayed so that it is not only excellent in diffusion effect but also sterilized due to charge transfer when it comes in contact with microorganisms such as bacteria, viruses and fungi.

In order to effectively sterilize the bacteria by electrostatic spraying, it is necessary to discharge droplets into the air or to store a large number of droplets in a specific space A system that maximizes the sterilization effect is needed.

Korean Patent Laid-Open No. 10-2015-0111533 (hereinafter referred to as "prior art") relates to an electrostatic atomizing nozzle and a method of manufacturing the electrostatic atomizing nozzle, An electrostatic spray nozzle for producing droplets by a spraying method and producing nanoparticles through such droplets, a method of manufacturing the same, and a nanoparticle synthesizing apparatus using the same.

Korean Patent Publication No. 10-2015-0111533

It is an object of the present invention to provide a manufacturing method for mass production of a micro nozzle array at a high yield.

Another object of the present invention is to provide an air cleaning apparatus including a micro-nozzle array.

An electrostatic atomizing system according to an embodiment of the present invention includes: a nozzle unit to which a fluid droplet is injected; An electrode unit disposed apart from the nozzle unit; A power supply unit for generating a voltage between the fluid sprayed through the nozzle unit and the electrode unit; And a power control unit for changing a direction of a voltage formed between the fluid and the electrode unit.

Further, the fluid may be water.

In addition, the nozzle unit may include a micro-nozzle array in which micro-nozzles are arranged.

In addition, the electrode unit may include an electrode having a mesh structure.

In addition, a fluid droplet having a negative charge may be emitted from the system if the direction of the voltage is set such that a negative voltage is applied to the fluid and the electrode is grounded.

In addition, a fluid droplet having a positive charge can be stored in the system when a negative voltage is applied to the electrode portion and a voltage direction is set such that the fluid is grounded.

In addition, the electrostatic spraying system may further include an inflow / outflow unit that allows the outside air to flow into and out of the system.

It may also include means for the inflow and outflow.

The liquid droplet having a positive charge sterilizes the outside air introduced into the system, and the inflow / outflow discharges sterilized outside air to the outside of the system. The electrostatic spray system does not humidify the outside of the system The outside air can be sterilized and circulated.

The present invention provides a humidifying sterilizer including an electrostatic atomizing system.

A method of manufacturing a polymeric micro-nozzle array manufacturing die having a plurality of micro-nozzles arranged on a base according to another embodiment of the present invention includes the steps of: a) forming a photoresist patterning corresponding to the micro-nozzle array on a substrate; b) filling the recess of the photosensitive agent patterning with metal; c) removing the residual photoresist between the filled metal; d) depositing a photosensitizer on the substrate, and then patterning the photosensitizer so that a hole is formed between the filled metals; e) filling the hole between the filled metal with a metal; And f) removing the remaining photoresist.

A method of manufacturing a micro-nozzle array of polymeric material having a plurality of micro-nozzles arranged on a base according to another embodiment of the present invention includes the steps of: a) forming a photoresist patterning corresponding to the micro-nozzle array on a substrate; b) filling the recess of the photosensitive agent patterning with metal; c) removing the residual photoresist between the filled metal; d) depositing a photosensitizer on the substrate, and then patterning the photosensitizer so that a hole is formed between the filled metals; e) filling the hole between the filled metal with a metal; f) removing the residual photoresist to produce a mold; And g) filling the mold with a polymer and then separating the polymer.

Also, the step a) may pattern the cylindrical protrusion having an outer diameter of 75 to 85 탆.

Also, the step b) may include a nickel plating process and a surface polishing process.

Also, the step d) may pattern the photoresist to form a hole having an outer diameter of 35 to 45 μm.

In addition, the polymer may include a thermosetting polymer or a thermoplastic polymer.

The method of manufacturing a micro-nozzle array according to the present invention is advantageous in mass production of a micro-nozzle array having the same structure based on a metal mold at a high yield.

In addition, the air cleaning apparatus according to the present invention can provide improved efficiency of the air cleaning and humidifying system by proposing a mechanism capable of converting the discharge and storage of water nano-droplets.

1 shows the electrostatic spraying principle.
FIG. 2 is a schematic view illustrating a micro-nozzle array according to an exemplary embodiment of the present invention and a micro-nozzle array fabricated according to the method of the present invention.
FIG. 3 shows a fine water droplet discharge mechanism through electrostatic spraying of an air cleaning apparatus according to an embodiment of the present invention.
FIG. 4 shows a fine water droplet storage mechanism through electrostatic spraying of an air cleaning apparatus according to another embodiment of the present invention.
5 shows the electrostatic sprayed water nano-droplet collecting / sterilizing effect of the air cleaning apparatus according to another embodiment of the present invention.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. However, the present invention is not limited to or limited by the exemplary embodiments. Like reference numerals in the drawings denote members performing substantially the same function.

The objects and effects of the present invention can be understood or clarified naturally by the following description, and the purpose and effect of the present invention are not limited by the following description. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail.

The present invention uses a mold for manufacturing a micro-nozzle array, and describes a mold manufacturing method for the micro-nozzle array.

A method of manufacturing a mold for manufacturing a micro-nozzle array of a polymer material having a plurality of micro-nozzles arranged on a base according to an embodiment of the present invention includes the steps of: a) forming a photoresist patterning corresponding to the micro-nozzle array on a substrate; b) filling the recess of the photosensitive agent patterning with metal; c) removing the residual photoresist between the filled metal; d) depositing a photosensitizer on the substrate, and then patterning the photosensitizer so that a hole is formed between the filled metals; e) filling the hole between the filled metal with a metal; And f) removing the remaining photoresist.

On the other hand, Fig. 1 shows the electrostatic spraying principle. Referring to FIG. 1, electrostatic spraying is a technique for atomizing a liquid by applying a high electric field to liquid supplied to a fine nozzle, using the surface change characteristic of the liquid. Electrostatic spray has various spray characteristics depending on applied voltage, flow rate, surface tension of liquid, electric conductivity, supply flow rate, etc. Cone jet mode electrostatic spray capable of stably spraying fine droplets is most . Cone jet mode Electrostatic atomization is the process of atomization by Taylor cone tip jet created by interaction of liquid surface tension and external electric force, secondary atomization by Rayleigh splitting phenomenon, Droplets can be created. Accordingly, when a nozzle having a size of several tens of micrometers is used, a liquid droplet having a size of hundreds of nanometers can be obtained, and as the diameter of the nozzle decreases due to the electrostatic spray characteristic, It is possible to spray more stably than when used.

2 is a schematic view showing a flow of a method of manufacturing a metal mold based on a micro-nozzle array according to an embodiment of the present invention. Referring to FIG. 2, a method of fabricating a micro-nozzle array of a polymer material having a plurality of micro-nozzles arranged on a base according to another embodiment of the present invention includes the steps of: a) patterning a photoresist pattern corresponding to the micro- ; b) filling the recess of the photosensitive agent patterning with metal; c) removing the residual photoresist between the filled metal; d) depositing a photosensitizer on the substrate, and then patterning the photosensitizer so that a hole is formed between the filled metals; e) filling the hole between the filled metal with a metal; f) removing the residual photosensitive agent to produce a mold; And g) filling the mold with a polymer and then separating the polymer.

Meanwhile, the step a) may pattern a cylindrical protrusion having an outer diameter of 75 to 85 μm. Also, the step b) may include a nickel plating process and a surface polishing process. Also, the step d) may pattern the photoresist to form a hole having an outer diameter of 35 to 45 μm. In addition, the polymer may include a thermosetting polymer or a thermoplastic polymer. Preferably, the polymer may use PDMS (poly dimethyl siloxane).

In detail, the method of manufacturing a micro-nozzle array according to the present invention can perform a process of duplicating a PDMS based on a metal mold in order to manufacture a micro-nozzle array of a nonconductive material. Metal molds can be made by nickel plating. The substrate may comprise copper. A negative photoresist can be applied to the copper substrate at a height of about 110 μm and a hole with a size of 100 μm can be formed with UV. The surface can then be planarized to a height of 100 μm from the bottom of the substrate using a CMP (Chemical Mechanical Polishing) process after filling the holes with nickel plating. Thereafter, a negative photoresist patterning for forming the holes of the nozzle array, a nickel plating and a CMP process are performed to obtain a mold capable of manufacturing a micro-nozzle array. When the PDMS is poured into the metal mold, it is hardened and separated from the mold, a micro-nozzle array of a nonconductive material can be obtained. The micro-nozzle array thus obtained can have a two-stage structure divided into a base and a nozzle.

An electrostatic spraying system according to an embodiment of the present invention includes a nozzle unit for injecting a fluid liquid droplet, an electrode unit disposed apart from the nozzle unit, a power source for forming a voltage between the fluid sprayed through the nozzle unit and the electrode unit And a power control unit for changing a direction of a voltage formed between the fluid and the electrode unit. The fluid to be sprayed may be water.

FIG. 3 shows a fine water droplet discharge mechanism through electrostatic spraying of an air cleaning apparatus according to an embodiment of the present invention. Referring to FIG. 3, a micro-nozzle array is applied to discharge a droplet of fine water to apply a cathode high voltage to water, and an electrode of the opposite net structure is grounded. In the electrode configuration, the water nano-droplets sprayed from the nozzle have a negative charge, so they can move to the grounded structure electrode. However, since the surrounding space can also be regarded as the ground in general, the liquid is discharged through the spraying system. The discharged water nano-droplets function to humidify the surrounding space or to sterilize airborne bacteria.

FIG. 4 shows a fine water droplet storage mechanism through electrostatic spraying of an air cleaning apparatus according to another embodiment of the present invention. Referring to FIG. 4, a water nano-droplet having a positive charge can be generated by applying grounding to water and applying a cathode high voltage to the net structure electrode as in FIG. The water nano-droplet is sprayed toward the net structure electrode and passes through the net structure electrode but fails to overcome the strong electric field of the net structure electrode and returns again. Finally, the droplets stay in the region near the electrode And stored in a specific area). As the number of droplets to be sprayed increases, the net structure electrode region becomes more supersaturated due to the increase of the droplet size. At this time, when the electrode structure is changed as shown in FIG. 3, the droplets of high concentration can be temporarily sprayed around.

Particularly, the fluid droplet having a positive charge sterilizes the outside air that has flowed into the system, and the outlet portion discharges sterilized outside air to the outside of the system. The electrostatic spraying system does not humidify the outside of the system The outside air can be sterilized and circulated. That is, the electrostatic spraying system according to the present invention is capable of sterilizing outside air inside a closed system in a state in which a system defined by an electrostatic spraying system is set to a closed system and a fluid droplet is prevented from flowing out of the closed system have.

Meanwhile, the spray nozzle may be a micro nozzle array. As the spray nozzle is provided with the micro-nozzle array, the amount of droplet sprayed onto the spray nozzle can be improved, thereby improving the known cleaning effect of the electrostatic spray system.

In addition, the electrode structure includes a plurality of voids, and droplets ejected from the atomization nozzle can pass through the voids. In particular, the electrode structure may include, but is not limited to, a structure such as a mesh electrode, a mesh structure, or the like. Particularly, as the droplet passes through the gap included in the electrode, the droplet may be stored in the system including the electrostatic spraying system, or the droplet may be discharged to the outside of the system.

More specifically, when a negative voltage is applied to the fluid and the direction of the voltage is set such that the electrode portion is grounded, a fluid droplet having a negative charge is discharged from the system, a negative voltage is applied to the electrode portion, A fluid droplet with positive charge can be stored inside the system if the direction of the voltage is set so as to be directed.

In particular, when liquid droplets are stored in the system, external air can flow into and out of the system to sterilize the outside air. To this end, the electrostatic atomizing system may further include an inflow / outflow unit for inflow / outflow of outside air. In addition, the inflow / outflow section may include means for inflow and outflow of outside air, which may include, but is not limited to, an air pump, a fan, and the like.

As such, the air cleaning apparatus according to the embodiment of the present invention can discharge the water nano-droplets to the surroundings or store them in the vicinity of the electrodes through electrode configuration conversion. Specifically, as shown in Fig. 3, the negative electrode may be connected to a water storage tank having a nozzle for discharging the water nano-droplet, and the electrode of the opposite net structure may be grounded.

Meanwhile, in order to store the water nano-droplet in a supersaturated state as shown in FIG. 4, the water storage tank having the nozzle may be grounded and the cathode may be connected to the opposite net structure electrode.

5 shows the electrostatic sprayed water nano-droplet collecting / sterilizing effect of the air cleaning apparatus according to another embodiment of the present invention. Referring to FIG. 5, the water nano-droplets generated through electrostatic spraying can perform a fine dust collecting function and a microbial sterilizing function. This is because the droplet has a characteristic of having a charge. Accordingly, the function of attracting fine dust in the air to the dust collecting plate and the sterilizing function through charge transfer can be performed. Accordingly, it is possible to provide a humidifying sterilizer including the electrostatic atomizing system of the present invention.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. will be. Therefore, the scope of the present invention should not be limited to the above-described embodiments, but should be determined by all changes or modifications derived from the scope of the appended claims and equivalents of the following claims.

Claims (16)

A nozzle part for ejecting a fluid droplet;
An electrode unit disposed apart from the nozzle unit;
A power supply unit for generating a voltage between the fluid sprayed through the nozzle unit and the electrode unit; And
And a power control unit for changing a direction of a voltage formed between the fluid and the electrode unit.
The method according to claim 1,
Wherein said fluid is water.
The method according to claim 1,
Wherein the nozzle section comprises a micro-nozzle array in which micro-nozzles are arranged.
The method according to claim 1,
Wherein the electrode portion comprises an electrode having a mesh structure.
The method according to claim 1,
Wherein a fluid droplet having a negative charge is emitted from the system when a negative voltage is applied to the fluid and a voltage direction is set such that the electrode portion is grounded.
The method according to claim 1,
Wherein a liquid droplet having a positive charge is stored within the system when a negative voltage is applied to the electrode portion and a direction of the voltage is set such that the fluid is grounded.
The method according to claim 6,
Wherein the system further comprises an inlet and outlet for introducing and discharging external air into and out of the system.
8. The method of claim 7,
And means for said inlet and outlet.
8. The method of claim 7,
The fluid droplet having a positive electric charge sterilizes the external air introduced into the system,
Wherein the inflow / outflow unit discharges sterilized outside air to the outside of the system,
Wherein the electrostatic spray system sterilizes and circulates outside air without humidifying the outside of the system.
A humidifying sterilizer comprising an electrostatic atomizing system according to any one of claims 1 to 9.
A method of manufacturing a mold for manufacturing a micro-nozzle array of a polymer material in which a plurality of micro-nozzles are arranged on a base,
a) forming a photoresist patterning on the substrate corresponding to the micro-nozzle array;
b) filling the recess of the photosensitive agent patterning with metal;
c) removing the residual photoresist between the filled metal;
d) depositing a photosensitizer on the substrate, and then patterning the photosensitizer so that a hole is formed between the filled metals;
e) filling the hole between the filled metal with a metal; And
f) removing the remaining photoresist. < RTI ID = 0.0 > 11. < / RTI >
A method of manufacturing a micro-nozzle array of a polymer material having a plurality of micro-nozzles arranged on a base,
a) forming a photoresist patterning on the substrate corresponding to the micro-nozzle array;
b) filling the recess of the photosensitive agent patterning with metal;
c) removing the residual photoresist between the filled metal;
d) depositing a photosensitizer on the substrate, and then patterning the photosensitizer so that a hole is formed between the filled metals;
e) filling the hole between the filled metal with a metal;
f) removing the residual photoresist to produce a mold; And
g) filling the mold with a polymer and then separating the polymer.
13. The method of claim 12,
Wherein the step a) is for patterning a cylindrical protrusion having an outer diameter of 75 to 85 탆.
13. The method of claim 12,
Wherein the step b) comprises a nickel plating process and a surface polishing step.
13. The method of claim 12,
Wherein the step d) comprises patterning the photosensitive agent so as to form a hole having an outer diameter of 35 to 45 탆.
13. The method of claim 12,
Wherein the polymer comprises a thermosetting polymer or a thermoplastic polymer.

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