JP2010248651A - Device and method for accumulating fine particle and fine particle accumulation film formed by the device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve denseness of a fine particle accumulation film by equalizing particle diameters on a target substrate. <P>SOLUTION: Two processes are alternately repeated: impacting of the fine particles on the target substrate 13; and canceling of an amount of electrostatic charges of the fine particles 18 on the target substrate 13 or of the fine particle accumulation film, which are performed by an adjusting part 32 of the amount of electrostatic charge. Thereby, the impacting of the fine particles is performed on the target substrate 13 after canceling positive electrostatic charge even when the fine particles 18 on the target substrate 13 or the fine particle accumulation film holds the positive electrostatic charge. Thus the fine particles are uniformly impacted on the target substrate 13, density of the fine particles on the target substrate 13 does not decrease, density of the fine particles is improved and the fine particle accumulation film are formed stably. Further, the probability of occurrence of electrostatic explosion is maintained constant and the particle diameters of the fine particles are equalized. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a fine particle deposition apparatus, a fine particle deposition method, and a fine particle deposition film formed by the apparatus for producing a fine particle deposition film or a structure including an aggregate of fine particles.

  This kind of fine particle deposition film is an aggregate of fine structures such as nanoparticles and nanofibers, and is used as, for example, a catalyst carrier or a filtration film, and as a heat insulating material, a low refractive index material, or a low dielectric constant material. Due to its availability, its versatility is widespread, and a wide variety of products are being developed and spread as the needs increase. In particular, a fine particle deposition film or structure using a resin material is easier and simpler to manufacture than a film using an inorganic material, has a low manufacturing cost, and is provided with various functional groups. Since it is relatively easy to achieve multiple functions, development is progressing toward various devices.

  A fine particle deposition film or structure using such a resin is produced by depositing resin nanoparticles or nanofibers, and several techniques for this purpose are provided. Among them, the electrospinning method (electrostatic spraying method) is performed in a non-vacuum state, and has attracted attention in various fields because it can be industrially produced in large quantities at a low cost with a simple apparatus configuration.

  For example, in Patent Document 1, a raw material liquid is fed into a spray mechanism at a high pressure, droplets of fine particles are blown out from the spray mechanism, and the droplets are further microparticulated by electrostatic explosion based on an electrospinning method. The technology to increase the productivity of is described.

  Further, in Patent Document 2, nanofibers are formed by an electrospinning method, and the nanofibers wound on the rotating collector are discharged while the nanofibers are wound around the rotating collector. The orientation is improved. Specifically, as shown in FIG. 8, a high voltage is applied between the nozzle 101 and the rotating collector 102, a resin solution is sent from the syringe 103 to the nozzle 101, a resin fiber is ejected from the nozzle 101, and electrostatic explosion occurs. Then, the nanofiber 105 is thinned into a nanofiber 105, the nanofiber 105 is wound around the rotating collector 102, and the nanofiber 105 on the circumferential surface of the rotating collector 102 is neutralized by the electrostatic removing device 104 to control the orientation of the nanofiber. Is making.

JP 2008-043944 A JP 2008-213187 A

  By the way, as an application example of the electrospinning method, there is a technique of depositing and depositing nano-order fine particles finely divided by electrostatic explosion on a target substrate to generate a fine particle deposited film on the target substrate.

  However, in such a method, since the fine particles and the fine particle deposition film are resin and have insulating properties, the charged charges of the fine particles that have landed on the target substrate are held without being discharged, and this causes the target substrate There is a problem that the electric field distribution around changes, the density of the fine particle deposition film decreases, and the particle size distribution of the fine particles becomes broad. Such a problem may also occur when the target substrate is an insulator, or when an insulating inorganic material is deposited in the form of fine particles by electrospinning.

  In general, in the electrospinning method, the particle size distribution of the fine particles often becomes a problem, and the finer the fine particles, the more difficult the uniform particle size becomes.

  However, the present situation is that no technology for effectively solving such a problem has been proposed yet. For example, in the technique of Patent Document 1, even if the fine particles can be further refined, the particle size of the fine particles cannot be made uniform or the density of the fine particle deposition film cannot be controlled. It cannot be solved. In the technique of Patent Document 2, the nanofiber 105 on the circumferential surface of the rotary collector 102 is neutralized by an electrostatic static neutralizer to control the orientation of the nanofiber 105. This static neutralization is performed between the nozzle 101 and the rotary collector 102. This is performed without correlation with the application of a high voltage. When the nanofiber 105 is wound around the peripheral surface of the rotating collector 102, such neutralization can be performed without any correlation with the application of a high voltage. If it is performed without correlation with the application of a high voltage, it is considered that control of fine particles becomes difficult.

  Therefore, the present invention has been made to solve the above-described conventional problems, and a fine particle deposition apparatus capable of uniformizing the particle size of the fine particles on the target substrate and improving the density of the fine particle deposition film, It is an object of the present invention to provide a fine particle deposition method and a fine particle deposition film formed by the apparatus.

  In order to solve the above problems, the fine particle deposition apparatus according to the present invention forms a liquid discharge unit that discharges liquid droplets toward a target substrate, and forms an electric field between the target substrate and the liquid droplet discharge unit by applying a voltage. And a voltage applying means for applying an electric charge to the droplets discharged from the droplet discharge unit, and the droplets directed to the target substrate are split and the fine particles formed by the splitting land and deposit on the target substrate. A fine particle deposition apparatus using an electrospinning method, comprising: a charged charge amount adjusting means for adjusting a charged charge amount of the droplets or fine particles; and a control means for controlling the voltage applying means and the charged charge amount adjusting means. I have.

  For example, the charged charge amount adjusting means adjusts the charged charge amount of fine particles deposited on the target substrate.

  Alternatively, the charged charge amount adjusting means adjusts the charged charge amount of droplets or fine particles before landing on the target substrate.

  In addition, a charge charge amount measuring unit that measures the charge amount of the droplets or fine particles is provided, and the control unit controls the charge charge amount adjusting unit based on a measurement result of the charge charge amount measuring unit. .

  For example, the charged charge amount measuring means measures the charged charge amount of the fine particles deposited on the target substrate.

  Alternatively, the charged charge amount measuring means measures the charged charge amount of droplets or fine particles before landing on the target substrate.

  Further, the control means controls the operation timing of the voltage applying means and the charged charge amount adjusting means.

  In addition, the droplets mainly include any one of a solution or melt containing a resin monomer or polymer, a dispersion in which resin or inorganic particles are dispersed, or a sol containing resin or inorganic particles. Ingredients.

  Further, a support unit for supporting the target substrate is provided, and the voltage application unit applies a voltage between the support unit and the droplet discharge unit to form an electric field between the target substrate and the droplet discharge unit. Yes.

  For example, the target substrate is an insulator, and at least a part of the support portion is a conductor connected to the voltage application unit.

  Next, the fine particle deposition method of the present invention includes a target substrate, a droplet discharge portion that discharges droplets toward the target substrate, and an electric field is formed between the target substrate and the droplet discharge portion by applying a voltage. Using voltage application means to apply electric charge to the droplets discharged from the droplet discharge unit, the droplets facing the target substrate are split, and the fine particles formed by this splitting land on the target substrate A particle deposition method using an electrospinning method, wherein the charge density of the droplets or particles is adjusted and controlled, and the voltage applied by the voltage applying unit is adjusted and controlled, whereby the particle density of the particles on the target substrate is adjusted. And manipulating particle size.

  The fine particle deposition film of the present invention is a fine particle deposition film formed by the fine particle deposition apparatus of the present invention, and is deposited by controlling the particle diameter and particle density of resin or inorganic to arbitrary values. Is formed.

  In the fine particle deposition apparatus of the present invention, a voltage applying means for forming an electric field between the target substrate and the droplet discharge portion and applying electric charge to the droplet discharged from the droplet discharge portion, and the charged charge amount of the droplet or the fine particle The charge charge amount adjusting means for adjusting the charge voltage and the voltage applying means and the control means for controlling the charge charge amount adjusting means are provided, so that the control of the applied voltage correlates with the adjustment of the charge charge amount of the droplets or fine particles. Can be done. This makes it possible to appropriately control the landing of the fine particles on the target substrate and the charged charge of the fine particles on the target substrate or the fine particle deposition film, thereby suppressing the change in the electric field distribution around the target substrate and reducing the fine particles. The density of the deposited film can be improved and the particle diameter of the fine particles can be made uniform.

  For example, the charged charge amount adjusting means adjusts the charged charge amount of the fine particles deposited on the target substrate. In this case, it is easy to adjust the charge amount of the fine particles.

  Alternatively, the charged charge amount adjusting means adjusts the charged charge amount of droplets or fine particles before landing on the target substrate. In this case, it is not necessary to adjust the charge amount of the fine particles or the fine particle deposition film on the target substrate, and the formation speed of the fine particle deposition film can be improved.

  In addition, a charge charge amount measuring unit that measures the charge amount of droplets or fine particles is provided, and the control unit controls the charge charge amount adjusting unit based on the measurement result of the charge charge amount measuring unit. This makes it possible to adjust the charge amount of the droplets or fine particles without excess or deficiency, and to further control the particle density and particle size.

  For example, the charged charge amount measuring means measures the charged charge amount of fine particles deposited on the target substrate. Alternatively, the charged charge amount measuring means measures the charged charge amount of the droplet or fine particle before landing on the target substrate. These measurement locations are preferably selected according to the location where the charge amount of the droplets or fine particles is adjusted by the charged charge amount adjusting means.

  For example, the control unit controls the operation timing of the voltage applying unit and the charged charge amount adjusting unit. Thereby, the deposition of the fine particles on the target substrate and the adjustment of the charged charges of the fine particles or the fine particle deposited film on the target substrate can be reliably performed.

  For example, the droplet is mainly composed of any one of a solution or melt containing a resin monomer or polymer, a dispersion in which resin or inorganic particles are dispersed, or a sol containing resin or inorganic particles. It is what. The application of the present invention is effective because any kind of droplets has an insulating property in the form of fine particles, because the charged charges of the fine particles or the fine particle deposition film on the target substrate are retained.

  Moreover, you may provide the support part which supports a target board | substrate. In this case, an electric field can be formed between the target substrate and the droplet discharge portion by applying a voltage between the support portion and the droplet discharge portion. In particular, if the target substrate is an insulator, it is necessary to apply such a voltage.

  On the other hand, also in the fine particle deposition method of the present invention, the same effects as the fine particle deposition apparatus of the present invention can be obtained.

  The fine particle deposition film of the present invention is formed by depositing while controlling the particle size and particle density of resin or inorganic to arbitrary values, and has stable characteristics.

It is a figure which shows the basic composition for implementing an electrospinning method. It is a figure which shows the microparticles | fine-particles and electric lines of force on the target board | substrate in FIG. It is a figure which shows the change of the charged charge amount of the droplet discharged from the capillary in FIG. 2 is an equivalent circuit equivalently showing a capillary, a target substrate, and the like in FIG. It is a block diagram which shows 1st Embodiment of the microparticle deposition apparatus of this invention. It is a block diagram which shows 2nd Embodiment of the microparticle deposition apparatus of this invention. (A) is a figure which expands and shows the fine particle deposited on the target board | substrate with the conventional apparatus, (b) is a figure which expands and shows the fine particle deposited on the target board | substrate with the apparatus of this invention. . It is a figure which illustrates the conventional apparatus which applied the electrospinning method.

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

  First, the basic principle of the electrospinning method (electrostatic spray method) which is a premise of the fine particle deposition apparatus and fine particle deposition method of the present invention will be described with reference to FIG.

  In FIG. 1, the voltage source 11 applies a pulsed high voltage of about several kV to several tens of kV between the capillary (droplet discharge unit) 12 and the target substrate 13, and generates an electric field between the capillary 12 and the target substrate 13. Then, the capillary 12 is positively charged and the target substrate 13 is negatively charged. Further, the resin solution 15 is supplied by pressure from the syringe 14 to the capillary 12. This resin solution 15 is a polymer solution.

  The resin solution 15 at the tip of the capillary 12 is positively charged in the same manner as the capillary 12, and is drawn to the target substrate 13 side by the electric field between the capillary 12 and the target substrate 13 and ejected as droplets 16.

The droplet 16 flies in the electric field from the capillary 12 to the target substrate 13. The amount of charge that can be held by the droplet itself is determined from the surface tension of the droplet and the Coulomb repulsive force between the surface charges, and is determined by the Rayleigh limit (q = 8π (εγr ³ ) ^1/2 ). Here, q is the charge amount of the droplet, ε is the vacuum dielectric constant, r is the particle size of the droplet, and γ is the viscosity of the droplet. By the time the droplet reaches the target substrate 13, the solvent of the droplet evaporates, the particle size r of the droplet becomes smaller, the droplet eventually reaches the Rayleigh limit, and an electrostatic explosion occurs in the droplet. Drops break up into particles.

  In the region 17 between the capillary 12 and the target substrate 13 in FIG. 1, the solvent evaporation and splitting of such droplets or particles are repeated, and the resin in the solution is precipitated into fine particles. The fine particles become the target substrate 13. The particle deposition film is formed on the target substrate 13. The above is the basic principle of the electrospinning method.

  Here, when the fine particles are made of an insulating resin, the charged charges of the fine particles that have landed on the target substrate 13 are held without being discharged, or the charged charges of the fine particles are only partially discharged. Most of the charged charges of the fine particles are retained and remain. In addition, the charged charges of the fine particles are retained even when the target substrate 13 has an insulating property regardless of the insulating properties of the fine particles.

  Thus, in the state where the charged charges of the fine particles that land on the target substrate 13 remain, the charged charges on the surface of the target substrate 13 are apparently canceled by the charged charges of the fine particles. As shown in FIG. 2, even if the surface of the target substrate 13 is negatively charged by the voltage application of the voltage source 11, positive charges remain on the fine particles 18 on the target substrate 13. The negative charge on the surface of the target substrate 13 is apparently canceled. At the location where the negative charge on the surface of the target substrate 13 is canceled, the electric lines of force 17 extending from the capillary 12 to the location disappear, so that the fine particles 18 do not land on this location. In addition, since the fine particles 18 themselves on the target substrate 13 hold a positive charge, other fine particles 18 newly flying near the fine particles 18 repel nearby. As a result, it becomes difficult for another particle to land near the location where the fine particles have landed once.

  For this reason, the fine particles 18 land on the target substrate 13 spatially and coarsely, the density of the fine particles becomes low, and the formation of the fine particle deposition film becomes difficult.

  Further, since the negative charge on the surface of the target substrate 13 apparently decreases due to the positive charge of the fine particles on the target substrate 13, the positive charge on the surface of the resin solution 15 at the tip of the capillary 12 also decreases, and the positive charge on the surface of the droplet decreases. To do. For this reason, the probability of occurrence of electrostatic explosion is reduced, the particle size of the fine particles is increased, and the particle size distribution of the fine particles is broadened.

  As shown in FIG. 3, at the beginning of droplet discharge from the capillary 12, the droplet 16 a holds a lot of surface charges, but with the passage of time, a large number of fine particles 18 are spread over the target substrate 13. , The negative charge of the target substrate 13 is apparently canceled in this wide range (electrostatic shielding region) 19, so the positive charge on the surface of the resin solution 15 at the tip of the capillary 12 is greatly reduced, and the surface of the droplet 16b The positive charge of is also greatly reduced. As a result, the probability of occurrence of electrostatic explosion is reduced, the particle size of the fine particles is increased, and the particle size distribution of the fine particles is broadened.

  Here, consider an equivalent circuit as shown in FIG. In this equivalent circuit, the capillary 12 and the target substrate 13 are replaced with the positive electrode 21 and the negative electrode 22 of the capacitor, and the layer of many fine particles 18 that have landed on the target substrate 13 is replaced with the insulating layer 23. As apparent from this equivalent circuit, even if the negative charge amount of the negative electrode 22 does not change, the apparent negative electrode when viewed from the positive electrode 21 side when the positive charge amount of the insulating layer 23 increases. The amount of negatively charged electric charge 22 decreases, and the amount of positively charged electric charge of the positive electrode 21 decreases. Therefore, the positive charge on the surface of the resin solution 15 at the tip of the capillary 12 in FIG. 3 is greatly reduced. For this reason, the positive charge on the surface of the droplet 16b is also greatly reduced, the probability of occurrence of electrostatic explosion is reduced, and the particle size of the fine particles is increased.

  That is, at the initial stage when droplet discharge from the capillary 12 is started, even if the particle size of the fine particles is small, the particle size of the fine particles increases with time, and the particle size distribution of the fine particles becomes broad.

  Therefore, in the fine particle deposition apparatus and the fine particle deposition method of the present invention, the charge on the surface of the fine particle on the target substrate is canceled or the charge of the opposite polarity is given to the fine particle surface to prevent the disappearance of the lines of electric force between the capillary and the target substrate. Or increase the lines of electric force. Alternatively, the charge on the surface of the droplet discharged from the capillary is prevented from decreasing, or the charge on the surface of the droplet is increased. As a result, a decrease in the density of the fine particles on the target substrate 13 can be prevented, or the density of the fine particles can be improved to stabilize the formation of the fine particle deposition film. Alternatively, the particle size of the fine particles can be made uniform while maintaining the probability of occurrence of electrostatic explosion constant.

  FIG. 5 is a block diagram showing a first embodiment of the fine particle deposition apparatus of the present invention. Note that, in FIG. 5, the same reference numerals are given to portions that perform the same operation as in FIG. 1. Further, the target substrate 13 is shown enlarged.

  In the fine particle deposition apparatus 31 of the present embodiment, a voltage source 11 that applies a pulsed high voltage of about several kV to several tens of kV between the capillary 12 and the target substrate 13, and a charge amount adjustment that is arranged near the target substrate 13. And a control unit 33 that controls the voltage source 11 and the charged charge amount adjustment unit 32.

  The charged charge amount adjusting unit 32 is for adjusting or canceling the charged charge amount of the fine particles 18 landed on the target substrate 13 or the fine particle deposition film formed by depositing the fine particles 18, and the fine particles 18 on the target substrate 13 or An atmospheric pressure plasma process, a corona discharge process, an ion irradiation process, or the like is performed on the fine particle deposition film to adjust or cancel the charged charge amount. The electrospinning method is usually performed at atmospheric pressure, but can also be performed at a low pressure if the viscosity of the solution and the boiling point of the solvent are appropriately set. When the electrospinning method is performed at a low pressure, it is possible to adjust or cancel the charged charge amount of the fine particles 18 or the fine particle deposited film by performing a low-pressure plasma treatment by the charged charge amount adjusting unit 32.

  The adjustment range of the charged charge amount by the charged charge amount adjusting unit 32 is the entire target substrate 13, but if there is a bias in the charged charge amount of the fine particles 18 or the fine particle deposition film on the target substrate 13, the charged charge amount is adjusted. A part of which the amount is biased may be set as the adjustment range of the charged charge amount.

  The control unit 33 controls the level of the high voltage output from the voltage source 11, the application timing or application period of the high voltage from the voltage source 11, and at the same time, the output level of the charge charge amount adjustment unit 32, the charge charge amount adjustment unit The adjustment timing or adjustment period of the charged charge amount by 32 can be controlled. For example, the control unit 33 alternately performs application of a high voltage by the voltage source 11 and adjustment of the charged charge amount by the charged charge amount adjusting unit 32. That is, the landing of the fine particles on the target substrate 13 and the cancellation of the charged charge amount of the fine particles 18 or the fine particle deposition film on the target substrate 13 are alternately repeated. Thereby, even if the fine particles 18 or the fine particle deposition film on the target substrate 13 hold a positive charge, the landing of the fine particles on the target substrate 13 is resumed after the positive charge is canceled. become. When the charged charge on the fine particles 18 or the fine particle deposition film on the target substrate 13 is canceled, the electric lines of force between the capillary 12 and the target substrate 13 do not disappear, and the charge on the surface of the droplet discharged from the capillary 11 decreases. You do n’t have to. When the fine particles land on the target substrate 13 in this state, the fine particles uniformly land on the target substrate 13, so that the density of the fine particles on the target substrate 13 is improved and the formation of the fine particle deposition film is performed. Stabilize. In addition, the probability of occurrence of electrostatic explosion is maintained constant, and the particle size of the fine particles becomes uniform.

  Note that it is not necessary to completely separate the application of a high voltage from the voltage source 11 and the adjustment of the charged charge amount by the charged charge amount adjusting unit 32, and there may be a time for simultaneous execution. In that case, since the particle formation and the surface charging treatment are performed simultaneously, there is an advantage that the deposition film forming speed is improved.

  Further, not only the charged charge amount adjusting unit 32 cancels the positive charged charge of the fine particles 18 or the fine particle deposited film on the target substrate 13, but also the charged charge amount adjusting unit 32 applies a negative charged charge to the fine particles or the fine particle deposited film. You may give. In this case, the positively charged fine particles land on the target substrate 13 and at the same time, the positively charged fine particles are attracted to and closely contacted with the negatively charged fine particles on the target substrate 13, so that the film quality and density of the fine particle deposition film are improved. Enhanced.

  FIG. 6 is a block diagram showing a second embodiment of the fine particle deposition apparatus of the present invention. In FIG. 6, the same reference numerals are given to portions that perform the same operations as those in FIGS. 1 and 5. Further, the target substrate 13 is shown enlarged.

  The fine particle deposition apparatus 41 of the present embodiment is obtained by adding a charged charge meter side portion 42 to the apparatus of FIG. The charged charge amount meter side unit 42 measures the charge amount of the fine particles 18 or the fine particle deposition film on the target substrate 13 and outputs the measurement result to the control unit 33. Examples of the charged charge meter side portion 42 include a Faraday cage.

  The control unit 33 monitors the measurement result of the charged charge amount meter side unit 42, that is, the charged charge amount of the fine particles 18 or the fine particle deposition film on the target substrate 13, so that the charged charge amount can be canceled appropriately. Further, the output level of the charged charge amount adjusting unit 32, the adjustment timing of the charged charge amount by the charged charge amount adjusting unit 32, or the adjustment period are controlled. This makes it possible to adjust the charged charge amount of the fine particles without excess or deficiency.

  The charged charge amount measuring unit 42 measures the charged charge amount of droplets or fine particles before landing on the target substrate 13, that is, the liquid in flight, instead of measuring the charged charge amount of the fine particles or fine particle deposition film on the target substrate 13. You may measure the charge amount of a droplet or a microparticle. In this case, the charge amount of the droplets or fine particles in flight is variously changed, and the density of the fine particles on the target substrate 13 is improved each time, the formation of the fine particle deposition film is stabilized, and the fine particle particles The charge charge amount adjustment unit 32 output level, charge charge adjustment timing by the charge charge amount adjustment unit 32, or adjustment period is determined in advance so that the diameter is uniform, that is, the fine particles or particle deposition film is optimized. deep. Then, the charged charge amount measuring unit 42 measures the charged charge amount of the flying droplets or fine particles, and the charged charge amount adjusting unit 32 performs optimization control of the fine particle or fine particle deposition film according to the measurement result.

  Further, the charged charge amount adjusting unit 32 adjusts the charged charge amount of the droplet or fine particles in flight before landing on the target substrate 13 instead of adjusting the charged charge amount of the fine particles or fine particle deposition film on the target substrate 13. You can adjust it. In this case, the optimum charged charge amount of the droplets or fine particles in flight so that the density of the fine particles on the target substrate 13 is improved, the formation of the fine particle deposition film is stabilized, and the particle size of the fine particles becomes uniform. The charge charge amount of the droplet or fine particle that is flying is measured by the charge charge amount measuring unit 42 in advance, and the charge amount of the droplet or fine particle that is flying is optimized by the charge charge amount adjusting unit 32. . Thereby, compared with the case where the charged charge amount of the fine particles or the fine particle deposition film is canceled after landing on the target substrate 13, the time allocated only for the cancellation of the charged charge amount is reduced, and the formation of the fine particle deposited film is reduced. Speed can be improved. Further, if the charge amount is controlled in the state of the droplet, the timing of electrostatic explosion of the droplet can be controlled, and the particle size and particle density of the fine particles can be controlled.

  The charged charge amount adjusting unit 32 not only cancels the positive charged charge of the fine particles 18 or the fine particle deposited film on the target substrate 13 but also the charged charge amount adjusting unit 32 negatively charges the fine particles 18 or the fine particle deposited film. May be given.

  In each of the above embodiments, a polymer solution is exemplified, but a polymer melt, a monomer solution or a melt, or a sol (colloid solution) containing resin or inorganic particles may be used. In the case of the monomer solution, after forming the fine particle deposition film, the fine particles can be polymerized to connect their interfaces, so that a finer particle deposition film can be formed. In the case of a sol, fine particles can be formed, and a gel fine particle deposition film can be produced by gelation by chemical reaction before the fine particles have landed or after the fine particles have landed and deposited.

  Furthermore, not only solutions and melts but also fine particles made of resin material or inorganic material may be prepared and the dispersion liquid may be used. As a method for producing fine particles in advance, a method using pulverization such as milling or laser crushing and a method of chemically synthesizing are known. In particular, methods for chemically synthesizing have been actively studied in recent years. For example, Japanese Patent Application Laid-Open No. 2004-292682 introduces a method for preparing a dispersion of polyimide fine particles having a diameter of about 30 nm using a coprecipitation method. Yes. By using these fine particles dispersed in a solution, a fine particle film can be produced even if it is difficult to make fine particles by electrospinning alone.

  In addition, when using a sol or dispersion containing inorganic particles having insulating properties, the application of the present invention is effective because the charged charges of the fine particles on the target substrate 13 are retained.

  Furthermore, as described above, even when the target substrate 13 has an insulating property regardless of the insulating property of the fine particles, the charged charges of the fine particles on the target substrate 13 are retained, so that the application of the present invention is effective. is there. In this case, in FIG. 5 and FIG. 6, the target substrate 13 is mounted and supported on the substrate support 43, and a pulsed high voltage is applied between the capillary 12 and the substrate support 43 to support the capillary 12 and the substrate. An electric field is formed between the bodies 43, and the target substrate 13 is disposed in the electric field so that the lines of electric force pass through the target substrate 13. For this purpose, at least a part of the substrate support 43 is formed of a conductive material. When the electric lines of force that deviate from the target substrate 13 increase, the number of fine particles that scatter away from the target substrate 13 increases. Therefore, in order to prevent the electric lines of force from deviating from the target substrate 13, a substrate support 43 made of a conductive material. It is necessary to specify the part. Even in such a configuration, the charged charge of the fine particles or the fine particle deposited film deposited and deposited on the insulating target substrate 13 is maintained, so that the present invention is applied to adjust the charged charge amount of the fine particles or the fine particle deposited film. Then, the density of the fine particles on the target substrate 13 is improved, and the formation of the fine particle deposited film is stabilized. In addition, the probability of occurrence of electrostatic explosion is maintained constant, and the particle size of the fine particles becomes uniform.

  Next, the inventors of the present invention implemented the present invention and conducted experiments on the examples, and the experimental results will be described.

  In this embodiment, an electrospinning device NSU-1 manufactured by Kato Tech Co., Ltd. is applied for discharging a resin solution. In addition, a target substrate in which a □ 50 × t2 mm copper plate is coated with an aluminum foil is used.

  Connect the capillary at the tip of the syringe to the positive output terminal of the voltage source, connect the target substrate to the ground terminal of the voltage source, apply a pulsed high voltage between the capillary and the target substrate, and connect between the capillary and the target substrate. An electric field was formed on the substrate, and positively charged droplets were allowed to fly from the capillary to the target substrate, causing the fine particles to land on the target substrate.

  Here, the syringe volume is 1 ml (inner diameter 2.2 mm), the droplet discharge speed is 0.75 ul / min (the syringe extrusion speed is 0.05 mm / min), and the capillary tip inner diameter is 0.5 mm. The transparent polyimide resin material is neoprim (polymer) manufactured by Mitsubishi Gas Chemical Company, and dimethylacetamide (DMAC) is used as a solvent for the solution, and the concentration of the solution is set to 7 wt%. The applied voltage is set to 25 kV.

  First, as in the conventional apparatus, the fine particles on the target substrate are deposited on the target substrate continuously for 5 minutes without canceling the charged charge of the fine particles on the target substrate or the fine particle deposition film. Observation was performed using a scanning electron microscope. The result is shown in FIG. As is apparent from FIG. 7A, although the fine particles are formed, the particle diameters of the fine particles are very varied, and the particles are not in close contact with each other, so that a dense film is not formed. This tendency did not change even when the deposition of fine particles was continued for a long time, and a dense film was not formed. This is because, as described above, the charged electric charge of the fine particles on the target substrate is retained and affects the surrounding electric lines of force.

  Therefore, in order to cancel the charged charge amount of the fine particles or the fine particle deposited film on the target substrate, a static eliminator SJ-M200 (charged charge amount adjusting unit) manufactured by Keyence Corporation was attached. This static eliminator SJ-M200 has a microhead that emits ions, and ion irradiation can be performed from the microhead to the target substrate.

  Then, this cycle was repeated 5 times, with the deposition of the fine particles for 1 minute and the cancellation of the charged charge of the fine particles for 1 to 2 minutes as one cycle. At the time of ion irradiation from the static eliminator, the charged charge amount of the fine particles on the target substrate is simply measured to confirm that the fine particles are positively charged or that the charged charge amount decreases and almost disappears. It could be confirmed. Moreover, the fine particles on the target substrate were observed using a scanning electron microscope. The result is shown in FIG. As apparent from FIG. 7B, it can be seen that the variation in the particle size of the fine particles is reduced, the particle size becomes uniform, and the fine particles are densely deposited to form a dense fine particle deposition film. . This is because the influence of the charged electric charges of the fine particles on the target substrate on the surrounding electric field lines is reduced.

  Such a fine particle deposition film of the present invention can be applied, for example, by depositing on a cover glass of a solar cell and using it as a protective film or an antireflection film. In this case, it is assumed that the fine particles have insulating properties. Moreover, even if the fine particles do not have insulating properties, the cover glass has insulating properties. For this reason, unless the charged charge of the fine particles landed on the cover glass is canceled, the particle diameters of the fine particles vary, the fine particles do not adhere to each other, and a dense film is not formed, resulting in an appearance problem. By applying the present invention, variation in the particle size of the fine particles is reduced, the particle size becomes uniform, and the fine particles are densely deposited to form a dense film, so that a preferable appearance can be obtained.

  As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to the example which concerns. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. It is understood.

  The present invention makes it possible to form a fine particle deposition film composed of fine particles having a uniform particle size regardless of the conductivity of a substrate or a coating material. For this reason, for example, by depositing fine particles made of a resin material or an inorganic material on a resin optical member while controlling the density, an optical functional film in which the refractive index, scattering, absorption, reflection, etc. are adjusted can be formed. Further, since such a fine particle deposition film can be formed in a non-vacuum state, a module including such an optical member or engineering member can be provided at low cost.

11 Voltage source 12 Capillary (droplet discharge part)
13 Target substrate 14 Syringe 15 Resin solution 16 Droplet 18 Fine particle 21 Positive electrode 22 Negative electrode 23 Insulating layers 31, 41 Fine particle deposition device 32 Charged charge amount adjusting unit 33 Control unit 42 Charged charge meter side unit 43 Substrate support

Claims (12)

A droplet discharge unit that discharges the droplet toward the target substrate, and an electric field is formed between the target substrate and the droplet discharge unit by applying a voltage, and an electric charge is applied to the droplet discharged from the droplet discharge unit. A fine particle deposition apparatus using an electrospinning method, comprising: a voltage applying means; and dividing droplets directed toward the target substrate and landing and depositing fine particles formed by the division on the target substrate,
Charged charge amount adjusting means for adjusting the charged charge amount of the droplets or fine particles;
A fine particle deposition apparatus comprising: control means for controlling the voltage applying means and the charged charge amount adjusting means. The fine particle deposition apparatus according to claim 1,
The charged particle amount adjusting means adjusts the charged charge amount of the particles deposited on the target substrate. The fine particle deposition apparatus according to claim 1,
The charged particle amount adjusting means adjusts the charged charge amount of droplets or particles before landing on a target substrate. The fine particle deposition apparatus according to any one of claims 1 to 3,
Charged charge amount measuring means for measuring the charged charge amount of the droplets or fine particles,
The fine particle deposition apparatus, wherein the control unit controls the charged charge amount adjusting unit based on a measurement result of the charged charge amount measuring unit. The fine particle deposition apparatus according to claim 4,
The charged charge amount measuring means measures a charged charge amount of fine particles deposited on a target substrate. The fine particle deposition apparatus according to claim 4,
The charged charge amount measuring means measures the charged charge amount of droplets or fine particles before landing on a target substrate. The fine particle deposition apparatus according to any one of claims 1 to 6,
The fine particle deposition apparatus, wherein the control means controls operation timing of the voltage applying means and the charged charge amount adjusting means. A particulate deposition apparatus according to any one of claims 1 to 7,
The droplet is mainly composed of any one of a solution or melt containing a resin monomer or polymer, a dispersion in which resin or inorganic particles are dispersed, or a sol containing resin or inorganic particles. A fine particle deposition apparatus. A particle deposition apparatus according to any one of claims 1 to 8,
A support unit for supporting the target substrate;
The fine particle deposition apparatus, wherein the voltage applying means applies a voltage between the support portion and the droplet discharge portion to form an electric field between the target substrate and the droplet discharge portion. The fine particle deposition apparatus according to claim 9, wherein
A fine particle deposition apparatus, wherein the target substrate is an insulator, and at least a part of the support portion is a conductor connected to the voltage applying means. A target substrate, a droplet discharge portion that discharges the droplet toward the target substrate, and an electric field is formed between the target substrate and the droplet discharge portion by applying a voltage, and the droplet is discharged from the droplet discharge portion. A particle deposition method using an electrospinning method in which droplets directed to the target substrate are split and the particles formed by the splitting land and deposit on the target substrate. There,
A fine particle deposition method characterized by controlling the charge density of the droplets or fine particles and adjusting the voltage applied by the voltage applying means to control the particle density and particle size of the fine particles on the target substrate. . A particulate deposition film formed by the particulate deposition apparatus according to any one of claims 1 to 10,
A fine particle deposition film formed by depositing while controlling the particle diameter and particle density of resin or inorganic to arbitrary values.

Images