Apparatus for producing fine particles, method for producing fine particles, cell for fine particle generation, and method for producing cell for fine particle generation

Abstract

[Problem] The present invention provides: an apparatus for producing fine particles, with which the mass productivity and production efficiency stability of fine particles are improved; a method for producing fine particles; a cell for fine particle generation; and a method for producing a cell for fine particle generation. [Solution] Disclosed is an apparatus 1 for producing fine particles, with which fine particles are produced by irradiating a solution 7 (a precursor solution 71), in which a precursor that contains a metal atom is mixed, with a femtosecond pulse laser 30a. The apparatus 1 for producing fine particles is characterized by being provided with: a cell 2 for fine particle generation, which is extended in the flow direction f of the solution 7; and an irradiation unit 3 which irradiates the solution 7 flowing in the cell 2 for fine particle generation with the femtosecond pulse laser 30a along the flow direction f. The cell 2 for fine particle generation may have: a first storage unit; a partition wall where an outflow hole through which the solution 7 flows out from the first storage unit and the femtosecond pulse laser 30a is condensed by the irradiation unit 3 is bored; and a second storage unit which stores the solution 7 that has flowed out from the first storage unit through the outflow hole.

Description

Microparticle manufacturing apparatus, method for manufacturing microparticles, cell for generating microparticles, and method for manufacturing cell for generating microparticles

[0001] This invention relates to a microparticle manufacturing apparatus, a method for manufacturing microparticles, a cell for generating microparticles, and a method for manufacturing a cell for generating microparticles.

[0002] Conventionally, as a method for efficiently producing metal microparticles, a continuous manufacturing process for transporting metal microparticles generated using a pulsed laser from a generation region has been proposed.

[0003] Patent Document 1 discloses a method for generating metal microparticles by irradiating a pulsed laser onto the surface of a precursor (target) in water while causing a water flow in a generation container.

[0004] Japanese Patent Application Laid-Open No. 2016-188428

[0005] According to the method disclosed in Patent Document 1, the region around the precursor can be cooled, the generated microparticles can be transported from the laser irradiation region to the recovery position, and the laser can be scanned onto the surface of the precursor installed in the irradiation region by a vibrating mirror, so that a decrease in the microparticle generation efficiency can be suppressed. However, according to the method of Patent Document 1, since the precursor is installed in a container, the accommodation capacity of the precursor is limited, and there is a problem that the mass productivity of microparticles cannot be improved. In addition, there is a problem that the stability of the microparticle generation efficiency cannot be improved, such as the possibility that the surface shape of the precursor changes with the generation of microparticles, causing the precursor surface to deviate from the irradiation region that can be operated by the vibrating mirror. [[ID=?]]

[0006] Therefore, the present invention has been devised in view of the above-described problems, and an object thereof is to provide a microparticle manufacturing apparatus, a method for manufacturing microparticles, a cell for generating microparticles, and a method for manufacturing a cell for generating microparticles in which the mass productivity and the stability of the generation efficiency of microparticles are improved.

[0007] The first invention relates to a microparticle manufacturing apparatus that manufactures microparticles by irradiating a solution containing a precursor with a metal atom with a femtosecond pulse laser, and is characterized by comprising: a microparticle generation cell extended in the direction of flow of the solution; and an irradiation unit that irradiates the solution flowing inside the microparticle generation cell with the femtosecond pulse laser along the direction of flow.

[0008] The microparticle manufacturing apparatus in the second invention is characterized in that, in the first invention, the microparticle generating cell comprises: a first storage section for storing the solution; a partition wall adjacent to the downstream end of the first storage section in the flow direction, having an outflow hole through which the solution flows out of the first storage section and through which the femtosecond pulse laser is focused by the irradiation section; and a second storage section adjacent to the downstream end of the partition wall in the flow direction, for storing the solution that has flowed out of the first storage section through the outflow hole.

[0009] The microparticle manufacturing apparatus in the third invention is characterized in that, in the second invention, the microparticle generating cell has an inner circumferential surface of the first housing portion that decreases in diameter as it approaches the partition wall.

[0010] The microparticle manufacturing apparatus in the fourth invention is characterized in that, in the first invention, the microparticle generation cell has a pair of reflectors at both ends in the flow direction that reflect the femtosecond pulse laser irradiated in the flow direction by the irradiation unit.

[0011] The microparticle manufacturing apparatus of the fifth invention is characterized in that, in the first invention, it further comprises an analysis unit for analyzing the components of the microparticles generated in the microparticle generation cell by laser-induced breakdown spectroscopy.

[0012] The microparticle manufacturing apparatus in the sixth invention is characterized in that, in the fifth invention, the analysis unit uses a laser branched from the femtosecond pulse laser irradiated by the irradiation unit as an excitation source.

[0013] The microparticle manufacturing apparatus in the seventh invention is characterized in that, in the fifth invention, the analysis unit uses the femtosecond pulse laser irradiated into the microparticle manufacturing cell by the irradiation unit as an excitation source to perform component analysis on the microparticles in the microparticle manufacturing cell.

[0014] The microparticle manufacturing apparatus in the eighth invention is characterized in that, in any of the first to seventh inventions, it further comprises a surface modification unit that brings the microparticles generated in the microparticle generation cell into contact with a surface modifier and separates the surface-modified microparticles from the precursor.

[0015] The ninth invention is a method for producing fine particles by irradiating a solution containing a precursor with metal atoms with a femtosecond pulse laser, characterized in that it includes an irradiation step of irradiating the solution flowing in a fine particle generation cell extended in the direction of the flow of the solution with the femtosecond pulse laser along the direction of the flow.

[0016] The microparticle generation cell in the tenth invention is used in a microparticle manufacturing apparatus that produces microparticles by irradiating a solution containing a precursor with metal atoms with a femtosecond pulse laser, and is a microparticle generation cell that extends in the direction of the flow of the solution and is irradiated with the solution flowing inside along the direction of the flow, and is characterized by having a first storage section for storing the solution, a partition wall adjacent to the first storage section in the direction of the flow and having an outflow hole through which the solution flows out of the first storage section and the femtosecond pulse laser is focused, and a second storage section adjacent to the partition wall in the direction of the flow and storing the solution that has flowed out of the first storage section through the outflow hole.

[0017] The microparticle generation cell in the 11th invention is used in a microparticle manufacturing apparatus that produces microparticles by irradiating a solution containing a precursor with metal atoms with a femtosecond pulse laser, and is a microparticle generation cell that extends in the direction of the flow of the solution and irradiates the solution flowing inside the cell with the femtosecond pulse laser along the direction of the flow, and is characterized in that it has a pair of reflectors at both ends in the direction of the flow that reflect the femtosecond pulse laser irradiated in the direction of the flow by the irradiation part.

[0018] The method for manufacturing a microparticle generation cell in the 12th invention is used in a microparticle manufacturing apparatus that manufactures microparticles by irradiating a solution containing a precursor mixed with metal atoms with a femtosecond pulse laser, and is a method for manufacturing a microparticle generation cell that extends in the direction of the flow of the solution and is irradiated with the solution flowing inside along the direction of the flow, characterized in that the femtosecond pulse laser is irradiated with a partition wall separating a first housing section and a second housing section that contain the solution and are adjacent to each other in the direction of the flow, thereby causing the solution to flow out of the first housing section and creating an outflow hole into which the femtosecond pulse laser is focused.

[0019] According to the first to eighth inventions, the microparticle manufacturing apparatus comprises a microparticle manufacturing cell that extends in the direction of solution flow and generates microparticles by focusing a femtosecond pulsed laser inside it, and an irradiation unit that irradiates the solution in the microparticle manufacturing cell with the femtosecond pulsed laser along the direction of flow. As a result, a microparticle manufacturing region can be formed that is longer in the direction of solution flow, and the laser can be reliably irradiated onto the flowing solution, enabling the continuous production of microparticles. Furthermore, after the start of microparticle production, the generated microparticles flow in the direction of flow, making it difficult for the microparticles to aggregate and preventing a decrease in laser transmittance. This makes it possible to improve the mass productivity and stability of the production efficiency of microparticles related to the microparticle manufacturing apparatus.

[0020] In particular, according to the second invention, the irradiation unit focuses a femtosecond pulse laser onto an outflow hole drilled in the partition wall of the microparticle generation cell. Therefore, the generation area can be optimized to match the shape of the outflow hole, and the energy of the laser light source can be suppressed. This makes it possible to reduce the labor involved in the production of microparticles in the microparticle manufacturing apparatus.

[0021] In particular, according to the third invention, the inner circumferential surface of the first housing section of the microparticle generation cell is narrowed in diameter as it approaches the partition wall. Therefore, compared to the case where the inner circumferential surface of the first housing section is not narrowed in diameter, the flow of the solution around the partition wall is less disturbed, and it is easier for the solution to pass smoothly through the outflow hole. This makes it possible to further improve the stability of the microparticle generation efficiency related to the microparticle manufacturing apparatus.

[0022] In particular, according to the fourth invention, the microparticle generation cell has a pair of reflective sections at both ends in the flow direction that reflect a femtosecond pulsed laser. Therefore, a wider generation area can be formed within the microparticle generation cell compared to when the laser is focused. This makes it possible to further improve the efficiency and stability of microparticle generation in the microparticle manufacturing apparatus.

[0023] In particular, according to the fifth invention, the microparticle manufacturing apparatus further includes an analysis unit that analyzes the components of microparticles generated in the microparticle generation cell by laser-induced breakdown spectroscopy. Therefore, the components of the generated microparticles can be continuously analyzed. This makes it possible to improve the quality stability of the microparticles produced by the microparticle manufacturing apparatus.

[0024] In particular, according to the sixth invention, the analysis unit uses a laser branched from the femtosecond pulsed laser irradiated by the irradiation unit as its excitation source. Therefore, there is no need to provide a separate laser for analysis. This makes it possible to reduce the labor involved in producing microparticles in the microparticle manufacturing apparatus.

[0025] In particular, according to the seventh invention, the analysis unit uses a femtosecond pulsed laser irradiated into the microparticle generation cell by the irradiation unit as an excitation source to analyze the components of the microparticles in the microparticle generation cell. Therefore, there is no need to newly install an analysis laser and cell. This makes it possible to reduce labor and space requirements for the microparticle manufacturing apparatus.

[0026] In particular, according to the eighth invention, the device further includes a surface modification unit that brings the microparticles generated in the microparticle generation cell into contact with a surface modifier, and separates the surface-modified microparticles from the precursor. Therefore, the generated microparticles can be continuously surface-modified, and only the surface-modified microparticles can be extracted and recovered. This makes it possible to improve the quality stability of the microparticles related to the microparticle manufacturing apparatus.

[0027] According to the ninth invention, the method for producing fine particles includes a step of flowing a solution in a fine particle generation cell extended in the direction of solution flow, and irradiating the solution with a femtosecond pulse laser along the direction of flow. As a result, a fine particle generation region can be formed for a longer duration in the direction of solution flow, and the laser is reliably irradiated onto the flowing solution, enabling the continuous production of fine particles. Furthermore, after the start of fine particle generation, the generated fine particles flow in the direction of flow, making them less likely to aggregate and preventing a decrease in laser transmittance. This makes it possible to improve the mass productivity and stability of the generation efficiency of fine particles in the fine particle manufacturing apparatus.

[0028] According to the tenth invention, the microparticle generation cell includes a first containment section for containing a solution, a partition wall with an outlet hole through which the solution flows out of the first containment section and a femtosecond pulse laser is focused, and a second containment section for containing the solution that has flowed out of the first containment section through the outlet hole. As a result, the laser is reliably irradiated onto the flowing solution, enabling the continuous production of microparticles. Furthermore, after the start of microparticle generation, the generated microparticles flow in the flow direction, making it difficult for the microparticles to aggregate and preventing a decrease in laser transmittance. This improves the mass productivity and stability of the generation efficiency of microparticles in the microparticle manufacturing apparatus. In addition, the generation area can be optimized to match the shape of the outlet hole, and the energy of the laser light source can be suppressed. This makes it possible to reduce the labor involved in producing microparticles in the microparticle manufacturing apparatus.

[0029] According to the eleventh invention, the microparticle generation cell has a pair of reflectors at both ends in the flow direction that reflect a femtosecond pulsed laser. Therefore, the laser is reliably irradiated onto the flowing solution, enabling the continuous production of microparticles. Furthermore, after the start of microparticle generation, the generated microparticles flow in the flow direction, making it difficult for the microparticles to aggregate and preventing a decrease in laser transmittance. This improves the mass productivity and stability of the generation efficiency of microparticles in the microparticle manufacturing apparatus. Moreover, a wider generation area can be formed within the microparticle generation cell compared to when the laser is focused. This further improves the stability of the generation efficiency of microparticles in the microparticle manufacturing apparatus.

[0030] According to the 12th invention, the method for manufacturing a cell for generating microparticles involves irradiating a femtosecond pulsed laser onto a partition wall separating a first and second adjacent containment section that contain a solution, causing the solution to flow out of the first containment section and creating an outlet hole into which the femtosecond pulsed laser beam is focused. As a result, a cell for continuously producing microparticles can be manufactured by reliably irradiating the flowing solution with the laser. Furthermore, after the start of microparticle generation, the generated microparticles flow in the direction of the flow, making it difficult for the microparticles to aggregate and preventing a decrease in laser transmittance. This improves the mass productivity and stability of the generation efficiency of microparticles in the microparticle manufacturing apparatus. In addition, the generation area can be optimized to match the shape of the outlet hole, and the energy of the laser light source can be suppressed. This makes it possible to reduce the labor involved in producing microparticles in the microparticle manufacturing apparatus.

[0031] Figure 1(a) is a schematic diagram showing an example of a microparticle manufacturing apparatus according to the first embodiment, and Figure 1(b) is a schematic diagram showing an example of a microparticle generating cell constituting the microparticle manufacturing apparatus. Figure 2 is a schematic diagram showing an example of a detailed configuration of the microparticle manufacturing apparatus according to the first embodiment. Figure 3 is a schematic diagram showing an example of an operation method for the microparticle generating cell constituting the microparticle manufacturing apparatus according to the first embodiment. Figures 4(a) to 4(b) are schematic diagrams showing a first modification of the operation method for the microparticle generating cell constituting the microparticle manufacturing apparatus according to the first embodiment. Figure 5 is a schematic diagram showing a second modification of the operation method for the microparticle generating cell constituting the microparticle manufacturing apparatus according to the first embodiment. Figures 6(a) to 6(b) are schematic diagrams showing a third modification of the operation method for the microparticle generating cell constituting the microparticle manufacturing apparatus according to the first embodiment. Figure 7 is a schematic diagram showing an example of a microparticle manufacturing apparatus according to the second embodiment. Figures 8(a) to 8(c) are schematic diagrams showing an example of a method for manufacturing the microparticle generating cell of Figure 4(b).

[0032] Hereinafter, with reference to the drawings, an example of a microparticle manufacturing apparatus 1, a method for manufacturing microparticles, a microparticle generation cell 2, and a method for manufacturing the microparticle generation cell 2 as embodiments of the present invention will be described in detail. In each figure, the first direction is X, the second direction is Y, which is one direction orthogonal to the first direction X, and the third direction is Z, which is a direction orthogonal to both the first direction X and the second direction Y. The configurations in each figure are schematically described for explanatory purposes, and for example, the size of each component and the size comparisons between components may differ from those shown in the figures.

[0033] (First Embodiment: Microparticle Manufacturing Apparatus 1) An example of the microparticle manufacturing apparatus 1 in this embodiment will be described with reference to the drawings.

[0034] The microparticles produced by the microparticle manufacturing apparatus 1 are used in electronic devices such as power generation elements, as well as in fields such as medicine and food. The microparticles may include metal microparticles, or they may include microparticles containing both metal and nonmetal atoms. The microparticles can be used, for example, in the energy field, such as power generation elements, or in the field of electronic devices, such as conductive components. In addition to the above, the microparticles can be used in fields such as medicine, such as pharmaceuticals or cosmetics, in the materials field, as part of composite materials, and in the food field. In particular, by performing any surface treatment (e.g., forming a coating) on ​​the surface of the microparticles, microparticles with added functions can be produced, and their application to a variety of uses is expected.

[0035] The microparticle manufacturing apparatus 1 is a device that produces microparticles or a solution 7 in which microparticles are suspended (colloidal solution 72) by irradiating a solution 7 (precursor solution 71) containing a precursor with metal atoms with a femtosecond pulse laser 30a, as shown in Figure 1(a), for example. In the following description, when simply referred to as microparticles, it refers to microparticles manufactured by the microparticle manufacturing apparatus 1. Also, when simply referred to as a laser, it refers to a femtosecond pulse laser.

[0036] The microparticle manufacturing apparatus 1 comprises, for example, a microparticle generation cell 2 and an irradiation unit 3. The microparticle manufacturing apparatus 1 may further comprise, for example, an input unit 4, an analysis unit 5, and a recovery unit 6.

[0037] The microparticle manufacturing apparatus 1, as shown in Figure 1(b), for example, comprises a microparticle generation cell 2 that extends in the flow direction f of the solution 7 and through which the solution 7 flows, and an irradiation unit 3 that irradiates the solution 7 in the microparticle generation cell 2 with a femtosecond pulse laser 30a along the flow direction f. That is, a long laser irradiation area is formed along the flow direction f of the solution 7. In this case, a long microparticle generation area can be formed along the flow direction f of the solution 7, and the laser is reliably irradiated onto the flowing solution 7, enabling the continuous production of microparticles. Furthermore, after the start of microparticle generation, the generated microparticles flow in the flow direction f, making it difficult for the microparticles to aggregate and preventing a decrease in laser transmittance. This improves the mass productivity and stability of the generation efficiency of microparticles produced by the microparticle manufacturing apparatus 1.

[0038] The microparticle manufacturing apparatus 1, as shown in Figure 2 for example, comprises a housing 10, a CPU (Central Processing Unit) 101, a ROM (Read Only Memory) 102, a RAM (Random Access Memory) 103, a storage unit 104, and a known computer having I / Fs 105 to 107. Each component 101 to 107 is connected by an internal bus 110. As the microparticle manufacturing apparatus 1, a portable electronic device such as a tablet terminal or a smartphone can be used.

[0039] The CPU 101 controls the entire microparticle manufacturing apparatus 1. The ROM 102 stores the operation code of the CPU 101. The RAM 103 is a work area used when the CPU 101 is operating. The storage unit 104 stores various information such as backups of the data stored in the ROM, databases, and learning target data. As the storage unit 104, a data storage device such as an HDD (Hard Disk Drive) or an SSD (Solid State Drive) can be used. For example, the microparticle manufacturing apparatus 1 may also have a GPU (Graphics Processing Unit) which is not shown.

[0040] I / F 105 is an interface for sending and receiving various information as needed via the wireless communication network 9. I / F 106 is an interface for sending and receiving information with the input unit 108. For example, a keyboard or mouse can be used as the input unit 108, and the user inputs various information via the input unit 108. I / F 107 is an interface for sending and receiving various information with the display unit 109. The display unit 109 displays various information stored in the storage unit 104, or evaluation results, etc. A display can be used as the display unit 109, and if it is a touch panel type, it is provided integrally with the input unit 108.

[0041] At least a part of each component of the fine particle manufacturing apparatus 1 is realized by the CPU 101 executing a program stored in the ROM 102, the storage unit 104, etc. with the RAM 103 as a working area. At least a part of each component of the fine particle manufacturing apparatus 1 may be executed by a human using the above computer as the main body.

[0042] <Fine particle generation cell 2> The fine particle generation cell 2 can accommodate a liquid, and a resin or quartz glass material that does not chemically react with a metal or metal ion, or other known materials that do not chemically react with the solution 7 and have excellent chemical resistance is used. The fine particle generation cell 2 is a container extending in the flow direction f of the solution 7.

[0043] As shown in, for example, Fig. 1(b), the fine particle generation cell 2 has a main body portion 20, an inlet 21, an outlet 22, an irradiation port plate 23 and a fixing member 24, and an observation window 25 and a window fixing member 26.

[0044] <Main body portion 20> The main body portion 20 is a hollow container extending in the flow direction f of the solution 7, and accommodates the solution 7 inside. For the main body portion 20, for example, a cylindrical shape or a polygonal cylindrical shape is used, and any shape through which the solution 7 can flow in the flow direction f can be used.

[0045] <Inlet 21, outlet 22> The inlet 21 and the outlet 22 communicate the inside and the outside of the main body portion 20. In the fine particle generation cell 2, for example, the solution 7 flows into the inside of the main body portion 20 through a solution tube 43d connected to the inlet 21, and the solution 7 flows out from the inside of the main body portion 20 through a solution tube 52 connected to the outlet 22.

[0046] The inlet 21 and the outlet 22 are provided at arbitrary positions on the side surface of the main body 20 where the solution 7 can flow in the flow direction f. For example, they are provided so as to be separated from each other in the first direction X when viewed in the direction of the third direction Z. In the example of FIG. 1(b), when the side surface of the main body 20 is oriented in the vertical direction, the inlet 21 and the outlet 22 are provided so as to be disposed above the side surface of the main body 20. However, the present invention is not limited to this, and the inlet 21 and the outlet 22 may be provided so as to be disposed below the side surface of the main body 20, or either one of the inlet 21 and the outlet 22 may be provided so as to be disposed above the side surface and the other may be disposed below the side surface.

[0047] <Irradiation port plate 23, fixing member 24> The irradiation port plate 23 is a member for transmitting the laser irradiated from the irradiation unit 3 into the main body 20. The irradiation port plate 23 is provided at one end portion in the extending direction of the main body 20 and is fixed by the fixing member 24. For example, quartz glass is used as the irradiation port plate 23. For example, resin is used as the fixing member 24.

[0048] The irradiation port plate 23 is provided at the end portion on the upstream side of the solution 7 among the end portions in the extending direction of the main body 20, that is, at the end portion on the inlet 21 side, in order to irradiate the laser from the upstream side in the flow direction f of the solution 7, for example. When the laser is irradiated from the downstream side in the flow direction f of the solution 7, for example, the irradiation port plate 23 may be provided at the end portion on the downstream side of the solution 7 among the end portions in the extending direction of the main body 20, that is, at the end portion on the outlet 22 side.

[0049] <Observation window 25, window fixing member 26> The observation window 25 is a window for observing the inside of the main body 20. The observation window 25 is provided at the other end portion in the extending direction of the main body 20 opposite to the end portion where the irradiation port plate 23 is provided and is fixed by the window fixing member 26. For example, quartz glass is used as the observation window 25. For example, resin is used as the window fixing member 26. By observing the inside of the main body 20 through the observation window 25, it is possible to visually recognize the generation state of fine particles, such as whether the fine particles are clogged and affecting the flow of the solution 7, and whether the laser can form an irradiation region in the main body 20.

[0050] <Irradiation Unit 3> The irradiation unit 3 irradiates the solution 7 flowing inside the microparticle generation cell with a femtosecond pulse laser 30a. The irradiation unit 3 irradiates the solution 7 with the femtosecond pulse laser 30a along the flow direction f, for example. The irradiation unit 3 includes, for example, an irradiation device 30 and a lens 31.

[0051] <Irradiation Device 30> The irradiation device 30 emits a pulsed laser with a time width of, for example, 10-15 seconds. The irradiation device 30 can be a femtosecond pulsed laser such as the Astrella manufactured by Coherent, exhibiting the following characteristics: Oscillation wavelength: 800 nm ± 20 nm Pulse width: 100 fs Energy: 5-9 mJ Repetition frequency: 100 Hz (output 0.5-0.9 W)

[0052] In addition to the above, the irradiation device 30 can be any device, such as the Spitfire Pro manufactured by Spectra Physics, and can be arbitrarily selected depending on the application. Note that the laser emitted from the irradiation device 30 has an energy of several mJ, and it is difficult to efficiently generate fine particles with an energy of several μJ, such as that used in laser processing.

[0053] <Lens 31> Lens 31 focuses the laser emitted from the irradiation device 30. By using lens 31, the light intensity can be increased for a specific area. In particular, by using lens 31, the laser can be focused into the interior of the solution 7 rather than at the interface of the solution 7. Known lenses such as focusing lenses can be used as lens 31. By irradiating the solution 7 with a laser focused through lens 31, the efficiency of fine particle generation can be improved.

[0054] The position in which the laser is focused into the solution 7 may be adjusted by, for example, adjusting the shape of the lens 31 or the distance from the solution 7. Alternatively, the position of the lens 31 may be fixed, and the position in which the laser is focused into the solution 7 may be adjusted using, for example, a variable focus lens.

[0055] <Input Unit 4> The input unit 4 is a device for transporting the solution 7 into the microparticle generation cell 2. The input unit 4, for example, contains the precursor solution 71 and uses air pressure to pump it into the microparticle generation cell 2.

[0056] The input section 4 includes, for example, an air compressor 41a, a pressurized tank 41c, and a needle valve 45.

[0057] The air compressor 41a is a known air compressor that generates compressed air. The air compressor 41a generates compressed air, for example, and transports the generated compressed air into the pressurized tank 41c via an air tube 41b made of a resin such as polypropylene.

[0058] The pressurized tank 41c is a known tank, such as one made of resin, that can contain liquid and does not chemically react with metals or metal ions. The pressurized tank 41c contains the precursor solution 71 inside. The pressurized tank 41c is connected to the microparticle generation cell 2 via solution tubes 43 (43a, 43b, 43d) made of resin such as polypropylene or silicone, a diameter conversion adapter 44 (44a, 44b), and a needle valve 45. The pressurized tank 41c is supplied with compressed air from, for example, an air compressor 41a, which increases the internal air pressure, and this air pressure is used to discharge the solution 7 into the solution tube 43a.

[0059] The pressurized tank 41c may be equipped with, for example, a magnetic stirrer 42a at the bottom and a stirring bar 42b inside. The stirring bar 42b is, for example, made of a magnetic material and can stir the precursor solution 71 in the sealed pressurized tank 41c by controlling the magnetic stirrer 42a.

[0060] The needle valve 45 adjusts the flow rate of the precursor solution 71 flowing from the pressurized tank 41c to the microparticle generation cell 2. The needle valve 45 is connected to the pressurized tank 41c, for example, via solution tubes 43a and 43b and a diameter conversion adapter 44a. The needle valve 45 is also connected to the microparticle generation cell 2, for example, via solution tubes 43c and 43d and a diameter conversion adapter 44b. If the needle valve 45 is not used, the pressurized tank 41c and the microparticle generation cell 2 may be directly connected via solution tube 43, but by using the needle valve 45, the flow rate of the solution 7 in the microparticle generation cell 2 can be controlled more reliably.

[0061] <Analysis Unit 5> Analysis Unit 5 is a device that performs non-contact, high-speed, and highly sensitive component analysis of fine particles using laser-induced breakdown spectroscopy (LIBS). By performing LIBS via Analysis Unit 5, the fine particle manufacturing apparatus 1 can manufacture fine particles and analyze the manufactured fine particles, thereby improving the mass productivity and quality stability of the fine particles.

[0062] LIBS is a type of atomic emission spectrometry that uses a high-energy pulsed laser as an excitation source. The analysis unit 5 may use LIBS to acquire information such as the elemental composition, crystal structure, particle size distribution, and shape of the fine particles. As the excitation source for LIBS, for example, a nanosecond pulsed laser or a femtosecond pulsed laser can be used, but a femtosecond pulsed laser is preferred over a nanosecond pulsed laser because its wavelength is shorter, resulting in better spectroscopic properties and allowing for the acquisition of the above information with higher precision.

[0063] The analysis unit 5 performs component analysis of the microparticles generated in the microparticle generation cell 2, for example, using LIBS. In this case, the components of the microparticles generated from the precursor solution 71 flowing within the microparticle generation cell 2 can be continuously analyzed. This improves the quality stability of the microparticles produced by the microparticle manufacturing apparatus 1.

[0064] Furthermore, the analysis unit 5 may use a laser branched from the femtosecond pulse laser 30a irradiated by the irradiation unit 3 as its excitation source. In this case, there is no need to provide a separate laser for analysis. This makes it possible to reduce the labor involved in producing microparticles in the microparticle manufacturing apparatus 1.

[0065] Furthermore, the analysis unit 5 may analyze the components of the microparticles in the microparticle generation cell 2 using the femtosecond pulsed laser 30a irradiated into the microparticle generation cell 2 by the irradiation unit 3 as an excitation source. In this case, there is no need to newly install an analysis laser and cell. This makes it possible to reduce labor and space requirements for the microparticle manufacturing apparatus 1.

[0066] The analysis unit 5 includes, for example, a flow cell 51 for spectroscopic observation, a spectrometer 53, an irradiation device 54 and lens 55, and a spectrometer 56 and lens 57.

[0067] The flow cell 51 for spectroscopic observation is a known container, such as one made of resin, that can contain a liquid and does not chemically react with metals or metal ions. The flow cell 51 for spectroscopic observation is connected to the microparticle generation cell 2 via a solution tube 52 made of the same material as the solution tube 43, for example. The colloidal solution 72 that flows out from the microparticle generation cell 2 and enters the flow cell 51 flows inside the spectroscopic observation flow cell 51.

[0068] The spectrometer 53 is a known particle size distribution measuring device for measuring the particle size of fine particles. The spectrometer 53 measures the particle size distribution of fine particles contained in the colloidal solution 72 by irradiating the colloidal solution 72 flowing through the spectroscopic observation flow cell 51 with white light 53a.

[0069] The irradiation device 54 uses a known laser device that irradiates the LIBS with a laser, which is the excitation source. The irradiation device 54 irradiates the colloidal solution 72 flowing through the spectroscopic observation flow cell 51 with a nanosecond pulsed laser 54a. As a result, the surface of the fine particles in the colloidal solution 72 emits plasma light. Subsequently, the emitted plasma light is decomposed into wavelengths via the lens 57 and the spectrometer 56, and the light intensity for each wavelength is detected. Then, by obtaining spectral data from the detected light intensity data, the elemental proportions of the fine particles in the colloidal solution 72 can be determined. Note that the elemental proportion data obtained using the analysis unit 5 is for the purpose of determining the composition ratio, and it is not necessary to determine the synthesis unevenness of the alloy fine particles or the spatial distribution of each component.

[0070] <Recovery Unit 6> The recovery unit 6 recovers and stores the colloidal solution 72 that has leaked out from the fine particle generation cell 2. The recovery unit 6 has a recovery tank 61.

[0071] The recovery tank 61 is a known tank, such as one made of resin, that can contain liquid and does not chemically react with metals or metal ions. The recovery tank 61 contains the colloidal solution 72. The recovery tank 61 is connected to the spectroscopic observation flow cell 51 via a solution tube 62 made of the same material as the solution tube 43, for example. The recovery tank 61 contains the colloidal solution 72 that flows out from the spectroscopic observation flow cell 51 and enters the tank. If the analysis unit 5 is not used, the microparticle generation cell 2 and the recovery tank 61 may be directly connected via the solution tube 62.

[0072] (First Embodiment: Method for Manufacturing Fine Particles) Next, with reference to the drawings, an example of the operation of the fine particle manufacturing apparatus 1 will be described as a method for manufacturing fine particles using the fine particle manufacturing apparatus 1 of this embodiment.

[0073] First, we will explain the microparticles produced by the microparticle manufacturing apparatus 1 and the solution 7 used in the operation of the microparticle manufacturing apparatus 1.

[0074] The fine particles produced by the fine particle manufacturing apparatus 1 include, for example, a plurality of particles having a particle size of 1 nm to 100 nm. The fine particles may include, for example, particles having a median diameter (central diameter: D50) of 1 nm to 10 nm, or particles having an average particle size of 1 nm to 10 nm. The median diameter or average particle size can be measured, for example, using a particle size distribution analyzer. As a particle size distribution analyzer, for example, a particle size distribution analyzer using the dynamic light scattering method (e.g., Malvern Panalytical Zetasizer Ultra) may be used.

[0075] The term "fine particles" can refer to a group of particles formed from a single metal, or, for example, a group of particles formed from multiple types of metal particles. The term "fine particles" may also refer to a group of particles formed from, for example, an alloy.

[0076] Examples of fine particles include those containing known metal atoms such as nickel, platinum, gold, and titanium. Fine particles may contain any of the following, as long as they contain metal atoms: pure metals, alloys that do not contain nonmetals, or metal oxides. Furthermore, when producing a colloidal solution in which fine particles of pure metals or alloys that do not contain nonmetals are dispersed, using alcohol as a solvent can reduce factors that promote oxidation of the fine particles. This allows for the provision of fine particles with better maintained quality.

[0077] The fine particles may, for example, exhibit a perovskite structure. The fine particles may contain at least one of the following: barium titanate (BaTiO3), strontium titanate (SrTiO3), calcium titanate (CaTiO3), lead titanate (PbTiO3), tin titanate (SnTiO3), cadmium titanate (CdTiO3), and strontium zirconate (SrZrO3).

[0078] The fine particles are, for example, a solid solution of a first metal atom and a second metal atom. In this case, compared to fine particles that are not solid solutions, partial state changes and chemical changes of the fine particles are less likely to occur, and the fine particles as a whole tend to exist more stably. This makes it possible to further improve the stability of the generated fine particles. Examples of metal atom combinations contained in solid solution fine particles include combinations of nickel and platinum, nickel and ruthenium, nickel and rhodium, nickel and palladium, nickel and iridium, etc. The solid solution fine particles may contain three or more types of metal atoms. As an example of a combination of metal atoms contained in solid solution fine particles, for example, a combination of metal atoms whose mixed enthalpy is 0 or less may be selected.

[0079] The microparticles are, for example, eutectic materials, which are a combination of a first metal atom and a second metal atom. In this case, the stability of the microparticles can be improved compared to microparticles that are not eutectic materials.

[0080] The fine particles may contain, for example, two or more materials exhibiting the same crystal structure. In this case, the crystal structure tends to be the same throughout the alloy's fine particles. This can improve the stability of the generated fine particles.

[0081] <Solution 7> Solution 7 is a fluid contained in each component of the microparticle manufacturing apparatus 1 and flows between or within each component. Solution 7 includes, for example, a precursor solution 71 and a colloidal solution 72.

[0082] <Precursor Solution 71> The precursor solution 71 is a liquid containing, for example, one or more ion precursor materials containing ions of atoms that constitute the fine particles. In this case, the fine particle manufacturing apparatus 1 can produce fine particles by irradiating the precursor solution 71 with a laser without using a reducing agent, and compared to a fine particle manufacturing method that uses a reducing agent, the generation of impurities derived from the reducing agent can be suppressed. This makes it possible to suppress a deterioration in the quality of the produced fine particles.

[0083] The precursor solution 71 may contain, for example, one ion precursor material, or it may contain a first ion precursor material and a second ion precursor material. The precursor solution 71 may contain a first ion precursor material containing a first metal atom and a second ion precursor material containing a second metal atom. The precursor solution 71 may contain one or more ion precursor materials containing three or more different metal atoms. By using such a precursor solution 71, the microparticle manufacturing apparatus 1 can produce alloy microparticles containing a first metal atom and a second metal atom, or alloy microparticles containing three or more different metal atoms.

[0084] The precursor solution 71 may be a liquid containing, for example, one or more powder materials containing atoms that constitute the fine particles. The precursor solution 71 may include, for example, a solvent and powder materials suspended in the solvent. In this case, the fine particle manufacturing apparatus 1 can generate fine particles by irradiating the powder materials suspended in the solvent in the precursor solution 71 with a laser.

[0085] The precursor solution 71 may contain, for example, one powder material, or it may contain a first powder material and a second powder material. The precursor solution 71 may contain a first powder material containing a first metal atom and a second powder material containing a second metal atom. The precursor solution 71 may contain one or more powder materials containing three or more different metal atoms. By using such a precursor solution 71, the microparticle manufacturing apparatus 1 can produce alloy microparticles containing a first metal atom and a second metal atom, or alloy microparticles containing three or more different metal atoms.

[0086] The powder material has a central diameter larger than, for example, fine particles. The powder material contains multiple particles having a finite particle diameter of, for example, 500 μm or less. The powder material contains particles having a central diameter of, for example, 50 nm or more and 100 μm or less.

[0087] The powder material directly reflects the composition of the resulting fine particles, and can therefore be arbitrarily set according to the type of fine particles to be produced. For example, if gold is used as the powder material, the resulting fine particles will contain gold. In this case, compared to a method of producing fine particles by reducing, for example, chlorauro(III) hydrate, the generation of impurities that may adhere to the fine particles can be suppressed. This helps to suppress a deterioration in the quality of the resulting fine particles.

[0088] The powder material includes, for example, one or more materials. For example, if the powder material includes two or more materials, fine particles of an alloy containing each material can be produced. The powder material includes, for example, known metal atoms such as nickel, platinum, gold, and titanium. The powder material may include, for example, pure metals, alloys that do not contain nonmetals, or metal oxides, as long as it contains metal atoms.

[0089] The powder material includes, for example, a first powder material and a second powder material. The first powder material contains a first metal atom. The second powder material contains a second metal atom different from the first metal atom. The first powder material has a different composition from, for example, the second powder material. In this case, the ratio of the first powder material to the second powder material can be adjusted, making it easier to control the composition ratio of each metal atom contained in the fine particles. This makes it possible to suppress variations in the composition ratio of each metal atom contained in the fine particles. For example, when using a powder material with a molar ratio of nickel to platinum of 8:2, fine particles with a composition close to nickel:platinum = 8:2 are likely to be produced.

[0090] The powder material may contain, for example, a second powder material having a higher melting point than the first powder material. In this case, fine particles are produced that have the properties of the first powder material but with a higher melting point than the first powder material. Compared to the case where fine particles are produced without using the second powder material, the temperature range in which the fine particles are stable can be expanded. This improves the stability of the fine particles.

[0091] The powder material may contain, for example, two or more materials exhibiting the same crystal structure. In this case, the crystal structure tends to be the same throughout the entire alloy of fine particles. This can improve the stability of the fine particles.

[0092] For example, the crystal structures of iron, sodium, and potassium exhibit a body-centered cubic lattice. Therefore, by including a powder material containing at least two of these elements (iron, sodium, and potassium), the entire resulting alloy of fine particles will exhibit a consistent crystal structure. Similarly, for example, the crystal structures of nickel, aluminum, and calcium exhibit a face-centered cubic lattice. Therefore, by including a powder material containing at least two of these elements (nickel, aluminum, and calcium), the entire resulting alloy of fine particles will exhibit a consistent crystal structure.

[0093] <Colloidal Solution 72> The colloidal solution 72 is a liquid containing fine particles generated by irradiating the precursor solution 71 with a laser. The colloidal solution 72 produced by the fine particle manufacturing apparatus 1 is used in the same fields as the fine particles described above. The colloidal solution 72 is, for example, a state in which two or more substances, including fine particles, are mixed.

[0094] The colloidal solution 72 comprises a solvent in which fine particles are dispersed. In this case, aggregation of the fine particles is more easily suppressed compared to when the fine particles are stored without a solvent. This makes it possible to provide fine particles with maintained quality.

[0095] Next, the operation method of the microparticle manufacturing apparatus 1 will be described. The operation method of the microparticle manufacturing apparatus 1 may include, for example, an irradiation step. The operation method of the microparticle manufacturing apparatus 1 may also include, for example, an analysis step after the irradiation step.

[0096] The microparticle manufacturing apparatus 1 may be implemented by having the CPU 101 execute a program stored in the ROM 102 or storage unit 104, etc., using the RAM 103 as a work area for each step of its operation method, or it may be implemented by a human using the above-mentioned computer.

[0097] <Preparation> Before the irradiation process, the operator prepares the solution 7 so that it can flow within the microparticle generation cell 2.

[0098] As shown in Figure 1, for example, the operator places the precursor solution 71 into the pressurized tank 41c and then seals the pressurized tank 41c. At this time, the needle valve 45 is closed. Subsequently, compressed air generated by the air compressor 41a is transported into the pressurized tank 41c to increase the pressure in the pressurized tank 41c. Then, by opening the needle valve 45, the precursor solution 71 in the pressurized tank 41c flows toward the microparticle generation cell 2.

[0099] Here, the operator may, after stirring or while stirring, the precursor solution 71 in the pressurized tank 41c into the microparticle generation cell 2 via the magnetic stirrer 42a and the agitator 42b. In this case, it becomes easier to uniformly irradiate the precursor solution 71 or the powder material in the precursor solution 71 with the laser. This improves the efficiency of microparticle generation. In particular, when the precursor solution 71 contains a first powder material containing a first metal atom and a second powder material containing a second metal atom, it becomes easier to maintain a state in which the first powder material and the second powder material are uniformly dispersed. In this case, the composition ratio of each metal contained in the microparticles of the solid solution microparticles containing the first metal atom and the second metal atom tends to become uniform. This makes it possible to produce microparticles with higher uniformity.

[0100] <Irradiation Process> In the irradiation process, the microparticle manufacturing apparatus 1 irradiates the solution 7 flowing in the microparticle generation cell 2, which is extended in the flow direction f of the solution 7, with a femtosecond pulsed laser 30a via the irradiation unit 3 along the flow direction f, as shown in Figure 3, for example. At this time, since the pulse width of the femtosecond pulsed laser 30a is shorter than the time it takes for the heat of the laser to be transferred to the solution 7, heat does not diffuse to areas other than the irradiated object. In this case, the energy of the laser is less likely to be consumed by reactions other than the generation of microparticles. This makes it possible to improve the efficiency of microparticle generation.

[0101] The flow direction f refers to the direction in which the solution 7 flows inside the main body 20 that constitutes the microparticle generation cell 2. When using a microparticle generation cell 2 that is extended in the flow direction f, the flow direction f is approximately parallel to the direction from one end to the other in the extension direction of the microparticle generation cell 2. In the example in Figure 3, the solution 7 flows into the main body 20 through the inlet 21 in the second direction Y, flows inside the main body 20 in the first direction X, and flows out to the outside of the main body 20 through the outlet 22 in the second direction Y. In this case, the flow direction f is the first direction X.

[0102] The laser irradiation direction along the flow direction f refers to a direction approximately parallel to the flow direction f (see Figures 3 to 5), or a direction in which the laser is irradiated from outside the microparticle generation cell 2, through the irradiation port plate 23, into the interior of the microparticle generation cell 2, forming an acute angle of incidence with respect to the flow direction f (see Figures 6(a) to 6(b)). When using a microparticle generation cell 2 extended in the flow direction f, the laser irradiation direction along the flow direction f is the direction from one end to the other in the extension direction of the microparticle generation cell 2. The laser irradiation direction along the flow direction f may also be the direction from the upstream end (inlet 21 side) to the downstream end (outlet 22 side) of the microparticle generation cell 2, or the direction from the downstream end to the upstream end of the microparticle generation cell 2.

[0103] The generation region 32 refers to the laser irradiation region, which is an excited reaction field where high energy derived from the laser is generated, necessary for reducing the ion precursor contained in the precursor solution 71 or for pulverizing the powder material contained in the precursor solution 71 to produce fine particles.

[0104] The generation region 32 includes a high-brightness plasma region generated along the optical axis of the laser when, for example, a femtosecond pulse laser 30a irradiated from the irradiation device 30 is focused by the lens 31, and a self-focused self-focusing region or a self-phase-modulated self-modulation region. That is, the generation region 32 is generated in a shape that is longer in the optical axis direction. Here, when the laser is irradiated along the flow direction f, the optical axis direction is along the flow direction f, so the generation region is formed to be longer in the flow direction f, and the precursor solution 71 that flows in the flow direction f and passes through the generation region 32 is easily irradiated by the laser, improving the efficiency of fine particle generation.

[0105] In other words, the irradiation process allows for the formation of a long microparticle generation region 32 in the flow direction f of the solution 7, and the laser is reliably irradiated onto the flowing solution 7, enabling the continuous production of microparticles. Furthermore, after the start of microparticle generation, the generated microparticles flow in the flow direction f, making them less prone to aggregation and preventing a decrease in laser transmittance. This improves the mass productivity and stability of the generation efficiency of microparticles produced by the microparticle manufacturing apparatus 1.

[0106] When a precursor solution 71 containing powder material is used as solution 7, in the irradiation step, the irradiation unit 3 irradiates the powder material flowing within the microparticle generation cell 2 with a femtosecond pulse laser 30a. In this case, compared to a microparticle manufacturing method that utilizes the reduction of metal ions, the generation of impurities that are produced due to the reduction reaction of metal ions and may affect the microparticles can be suppressed. As a result, microparticles that are less prone to quality degradation can be produced.

[0107] The irradiation step may involve irradiating a powder material containing, for example, a first powder material containing a first metal atom and a second powder material containing a first metal atom, with a femtosecond pulse laser 30a. At this time, alloy fine particles containing the first and second metal atoms are generated. In this case, the ratio of the first powder material to the second powder material can be adjusted, making it easier to control the composition ratio of each metal atom contained in the fine particles. This makes it possible to generate fine particles in which variations in the composition ratio of each contained metal atom are suppressed.

[0108] The irradiation step may involve irradiating a powder material containing, for example, a first powder material and a second powder material having a higher melting point than the first powder material, with a femtosecond pulsed laser 30a. That is, fine particles having the properties of the first powder material and a higher melting point than the first powder material are produced. In this case, compared to the case where fine particles are produced without using the second powder material, the temperature range in which the fine particles are stable can be expanded. This makes it possible to produce highly stable fine particles.

[0109] The irradiation step may involve irradiating a powder material containing a first metal atom and a second metal atom with a femtosecond pulsed laser 30a to generate solid solution fine particles combining the first and second metal atoms. In this case, compared to fine particles that are not solid solutions, partial state changes and chemical changes in the fine particles are less likely to occur. This makes it possible to manufacture highly stable fine particles.

[0110] The irradiation step may involve irradiating a powder material containing a first metal atom and a second metal atom with a femtosecond pulsed laser 30a to generate eutectic fine particles of the first and second metal atoms. In this case, fine particles with higher stability can be produced compared to non-eutectic fine particles.

[0111] <Analysis Process> In the analysis process, the microparticle manufacturing apparatus 1 performs component analysis or particle size distribution measurement of the microparticles generated in the microparticle generation cell 2 by the irradiation process, for example via the analysis unit 5. The microparticle manufacturing apparatus 1 also performs component analysis or particle size distribution measurement of the microparticles flowing in the spectroscopic observation flow cell 51, for example via the analysis unit 5.

[0112] After the irradiation or analysis step, the microparticle manufacturing apparatus 1 recovers the colloidal solution 72 generated by the irradiation step, for example, via the recovery unit 6. The microparticle manufacturing apparatus 1 also recovers the colloidal solution 72 discharged from the microparticle generation cell 2 or the spectroscopic observation flow cell 51, for example, via the recovery tank 61 and the solution tube 62.

[0113] The above steps complete the production of the fine particles and the colloidal solution 72 in this embodiment.

[0114] Furthermore, if the microparticle manufacturing apparatus 1 has, for example, known solenoid valves at the inlet 21 and outlet 22 of the microparticle generation cell 2, the flow of the solution 7 in the microparticle generation cell 2 may be temporarily stopped by opening and closing the solenoid valves during or before / after the irradiation process, thereby continuously performing a so-called batch-type microparticle manufacturing process. In this case, it is easier to produce microparticles with a smaller particle size distribution. This makes it possible to improve the quality stability of the microparticles produced by the microparticle manufacturing apparatus 1.

[0115] Furthermore, after the production of the fine particles and colloidal solution 72 in this embodiment is complete, the precursor solution 71 in the pressurized tank 41c may be removed, the washing solution may be added, and the washing solution may be pumped into the fine particle generation cell 2, the spectroscopic observation flow cell 51, and the recovery tank 61 using compressed air generated by the air compressor 41a. As the washing solution, any known dissolving solution that can dissolve the metal contained in the precursor solution 71 may be used. For example, aqua regia, a mixture of hydrochloric acid and hydrogen peroxide, a mixture of sulfuric acid and hydrogen peroxide, nitric acid, hydrochloric acid, sodium nitrate, etc., may be used.

[0116] Furthermore, after the production of the fine particles and the colloidal solution 72 is completed, if it is difficult to wash away impurities from the fine particle generation cell 2, the operator may remove the fine particle generation cell 2 and replace it with a new fine particle generation cell 2.

[0117] (First Embodiment: First Modification of the Fine Particle Manufacturing Apparatus 1 and Method for Manufacturing Fine Particles) The fine particle generation cell 2 may have a main body 20 that includes a reference portion 27 and a reduced diameter portion 28, as shown in Figure 4(a). The reference portion 27 consists of, for example, a first housing portion 27a on the upstream side in the flow direction f and a second housing portion 27b on the downstream side in the flow direction f. The reduced diameter portion 28 is formed such that the peripheral wall corresponding to the side surface of the main body 20 has a diameter in the width direction (YZ plane direction in Figure 4(a)) that is smaller than the diameter in the width direction of the first housing portion 27a and the second housing portion 27b, and it connects the housing portions 27a and 27b to each other while also serving as a partition wall separating the housing portions 27a and 27b. In other words, the microparticle generation cell 2 has a first containment section 27a, a diameter-reducing section 28 of a partition wall adjacent to the downstream end of the first containment section 27a in the flow direction f, which allows the solution 7 to flow out from the first containment section 27a, and a second containment section 27b adjacent to the downstream end of the diameter-reducing section 28 in the flow direction f, which contains the solution 7 that has flowed out from the first containment section 27a via the diameter-reducing section 28.

[0118] According to the example in Figure 4(a), the irradiation unit 3 (irradiation process) focuses the femtosecond pulse laser 30a onto the diameter-reducing section 28 to form a generation region 32 in the diameter-reducing section 28. The irradiation unit 3 (irradiation process) may, for example, form a generation region 32 in the diameter-reducing section 28 that is approximately the same size as the diameter of the diameter-reducing section 28 in the width direction. In this case, the generation region 32 can be optimized to match the shape of the diameter-reducing section 28, and the energy of the laser light source can be suppressed. This makes it possible to reduce the labor involved in producing microparticles in the microparticle manufacturing apparatus 1.

[0119] Furthermore, the microparticle generation cell 2 may have a partition wall 28a provided on the inner circumferential surface of the main body 20, with an outflow hole drilled in a part of it, as shown in Figure 4(b). That is, the microparticle generation cell 2 has a first housing section 27a, a partition wall 28a adjacent to the downstream end of the first housing section 27a in the flow direction f, with an outflow hole drilled in it for draining the solution 7 from the first housing section 27a, and a second housing section 27b adjacent to the downstream end of the partition wall 28a in the flow direction f, for housing the solution 7 that has drained from the first housing section 27a through the outflow hole. The femtosecond pulse laser is focused onto the partition wall 28a by the irradiation section 3. In this case, the molding of the main body 20 is easier compared to the case in which the circumferential wall of the main body 20 is reduced in diameter, and manufacturability can be improved.

[0120] The partition wall 28a is made of the same material as the main body 20, and may be made of a known resin, for example. The partition wall 28a may be integrally molded with the main body 20, or it may be integrated from separate components.

[0121] In the example shown in Figure 4(b), the irradiation unit 3 (irradiation process) may focus the femtosecond pulse laser 30a onto the outflow hole to form a generation region 32 in the outflow hole that is approximately the same diameter as the outflow hole. That is, the irradiation unit 3 (irradiation process) of the microparticle manufacturing apparatus 1 focuses the femtosecond pulse laser 30a onto the outflow hole drilled in the partition wall of the microparticle generation cell 2. In this case, the generation region 32 can be optimized to match the shape of the outflow hole, and the energy of the laser light source can be suppressed. This makes it possible to reduce the effort required to produce microparticles in the microparticle manufacturing apparatus 1.

[0122] Furthermore, the diameter of the first housing section 27a may decrease as its inner circumferential surface approaches the partition wall 28a. In this case, compared to the case where the inner circumferential surface of the first housing section 27a does not decrease in diameter, the flow of the solution 7 around the partition wall 28a is less likely to be disturbed, and it is easier for the solution to pass smoothly through the outflow hole. This makes it possible to further improve the stability of the fine particle production efficiency related to the fine particle manufacturing apparatus 1.

[0123] (First Embodiment: Second Modification of the Microparticle Manufacturing Apparatus 1 and Method for Manufacturing Microparticles) The microparticle generating cell 2 has a pair of reflectors (reflectors 33, reflectors 34) at both ends in the flow direction f, i.e., at both ends in the extension direction of the main body 20, as shown in Figure 5, for example. The microparticle generating cell 2 reflects the femtosecond pulse laser 30a irradiated in the flow direction f by the irradiation unit 3 via, for example, each reflector 33, 34. For each reflector 33, 34, for example, known glass mirrors may be used.

[0124] Each reflective portion 33, 34 is positioned, for example, on the optical axis of the femtosecond pulse laser 30a. Each reflective portion 33, 34 is fixed, for example, to the end surface of the main body 20 in the extension direction. Reflective portion 33 is fixed, for example, on a fixing member 24. Reflective portion 33 is fixed, for example, on a window fixing member 26.

[0125] In the example shown in Figure 5, the irradiation unit 3 (irradiation process) irradiates a femtosecond pulse laser 30a onto a pair of reflectors arranged on the optical axis. At this time, the femtosecond pulse laser 30a passes through the lens 31, then through the reflector 33, is reflected by the reflector 34, and then reflected back to the reflector 33. As a result, a generation region 32 is formed between the pair of reflectors. In this case, a wider generation region 32 can be formed within the microparticle generation cell 2 compared to when the laser is focused. This makes it possible to further improve the efficiency and stability of microparticle generation in the microparticle manufacturing apparatus 1.

[0126] Furthermore, as shown in Figure 5, in order to form a wider generation region 32 between the pair of reflective parts, it is preferable that the focal length of the lens 31 be at least twice the length of the main body 20 in the extension direction. Also, if the generation region 32 can be formed by the output of the femtosecond pulse laser 30a without focusing the femtosecond pulse laser 30a, then the lens 31 may not be provided.

[0127] (First Embodiment: Third Modification of the Microparticle Manufacturing Apparatus 1 and Method for Manufacturing Microparticles) The microparticle generating cell 2, as shown in Figures 6(a) to 6(b), for example, has further reflective sections 35 and 36 on the peripheral wall perpendicular to the flow direction f, i.e., the peripheral wall in the width direction (radial direction) of the main body 20, in addition to the reflective sections 33 and 34. The microparticle generating cell 2 reflects the femtosecond pulse laser 30a irradiated by the irradiation unit 3 at an acute angle of incidence with respect to the flow direction f, for example, via the reflective sections 33 to 36. For example, materials of the same quality as the reflective sections 35 and 36 may be used for each reflective section 35 and 36.

[0128] Each of the reflectors 35, 36 is positioned, for example, on the optical axis of the femtosecond pulse laser 30a. Each of the reflectors 35, 36 extends, for example, in the direction of extension of the main body 20 and is fixed in place of the peripheral wall of the main body 20, or on the inner surface of the peripheral wall of the main body 20.

[0129] Each reflective portion 35, 36 may be spaced apart from each other in the width direction of the main body 20, or they may be continuous with each other and constitute part or all of the peripheral wall of the main body 20. Each reflective portion 35, 36 may be spaced apart from each other in the second direction Y in the width direction of the main body 20, as shown in Figure 6(a), or they may be spaced apart from each other in the third direction Z in the width direction of the main body 20, as shown in Figure 6(b). Furthermore, the main body 20 may consist only of each reflective portion 33 to 36.

[0130] In the example shown in Figures 6(a) to 6(b), the irradiation unit 3 (irradiation process) irradiates a femtosecond pulse laser 30a onto a reflector 36 positioned on the optical axis. At this time, the femtosecond pulse laser 30a passes through the lens 31, then through the reflector 33 and is reflected by the reflector 36, and then can be reflected by each reflector 34, 35 and then reflected back to the reflector 33. As a result, a generation region 32 is formed in the space surrounded by each reflector 33 to 36. In this case, a wider generation region 32 can be formed within the microparticle generation cell 2 compared to when the laser is focused. This makes it possible to further improve the efficiency and stability of microparticle generation in the microparticle manufacturing apparatus 1.

[0131] Furthermore, as shown in Figures 6(a) to 6(b), in order to form a wide generation region 32 by the space enclosed by each of the reflective parts 33 to 36, the focal length of the lens 31 is preferably 2 / cosθ times or more, where θ is the angle of incidence of the femtosecond pulse laser 30a with respect to the flow direction f. Also, if the generation region 32 can be formed by the output of the femtosecond pulse laser 30a without focusing the femtosecond pulse laser 30a, then the lens 31 may not be provided.

[0132] According to this embodiment, the microparticle manufacturing apparatus 1 includes a microparticle manufacturing cell 2 that extends in the flow direction f of the solution 7 and generates microparticles by focusing a femtosecond pulse laser 30a inside it, and an irradiation unit 3 that irradiates the solution 7 (precursor solution 71) in the microparticle manufacturing cell 2 with the femtosecond pulse laser 30a along the flow direction f. As a result, a long microparticle manufacturing region 32 can be formed in the flow direction f of the solution 7 (precursor solution 71), and the laser can be reliably irradiated onto the flowing solution 7 (precursor solution 71) to continuously manufacture microparticles. Furthermore, after the start of microparticle manufacturing, the generated microparticles flow in the flow direction f, so the microparticles are less likely to aggregate, and the laser transmittance is less likely to decrease. This makes it possible to improve the mass productivity and stability of the production efficiency of microparticles related to the microparticle manufacturing apparatus 1.

[0133] Furthermore, according to this embodiment, the irradiation unit 3 focuses the femtosecond pulse laser 30a onto the outflow hole drilled in the partition wall 28a of the microparticle generation cell 2. Therefore, the generation area 32 can be optimized to match the shape of the outflow hole, and the energy of the laser light source can be suppressed. This makes it possible to reduce the labor involved in producing microparticles in the microparticle manufacturing apparatus 1.

[0134] Furthermore, according to this embodiment, the inner circumferential surface of the first housing section 27a of the fine particle generation cell 2 is reduced in diameter as it approaches the partition wall 28a. Therefore, compared to the case where the inner circumferential surface of the first housing section 27a is not reduced in diameter, the flow of the solution 7 (precursor solution 71) is less disturbed around the partition wall 28a, and it is easier for it to pass smoothly through the outflow hole. This makes it possible to further improve the stability of the fine particle generation efficiency of the fine particle manufacturing apparatus 1.

[0135] Furthermore, according to this embodiment, the microparticle generation cell 2 has a pair of reflective sections at both ends in the flow direction f that reflect the femtosecond pulse laser 30a. Therefore, a wider generation area 32 can be formed within the microparticle generation cell 2 compared to when the laser is focused. This makes it possible to further improve the stability of the microparticle generation efficiency of the microparticle manufacturing apparatus 1.

[0136] Furthermore, according to this embodiment, the microparticle manufacturing apparatus 1 further includes an analysis unit 5 that analyzes the components of microparticles generated in the microparticle generation cell 2 by laser-induced breakdown spectroscopy. Therefore, the components of the generated microparticles can be continuously analyzed. This makes it possible to improve the quality stability of the microparticles produced by the microparticle manufacturing apparatus 1.

[0137] Furthermore, according to this embodiment, the analysis unit 5 uses a laser branched from the femtosecond pulse laser 30a irradiated by the irradiation unit 3 as its excitation source. Therefore, there is no need to provide a separate laser for analysis. This makes it possible to reduce the labor involved in producing microparticles in the microparticle manufacturing apparatus 1.

[0138] Furthermore, according to this embodiment, the analysis unit 5 uses the femtosecond pulse laser 30a irradiated into the microparticle generation cell 2 by the irradiation unit 3 as an excitation source to analyze the components of the microparticles in the microparticle generation cell 2. Therefore, there is no need to newly install an analysis laser and cell. This makes it possible to reduce labor and space requirements for the microparticle manufacturing apparatus 1.

[0139] Furthermore, according to this embodiment, the method for manufacturing fine particles includes a step of flowing the solution 7 (precursor solution 71) into a fine particle generation cell 2 that extends in the flow direction f of the solution 7 (precursor solution 71), and irradiating the solution 7 (precursor solution 71) with a femtosecond pulse laser 30a along the flow direction f. As a result, a fine particle generation region 32 can be formed over a long distance in the flow direction f of the solution 7 (precursor solution 71), and the laser is reliably irradiated onto the flowing solution 7 (precursor solution 71), enabling the continuous production of fine particles. In addition, after the start of fine particle generation, the generated fine particles flow in the flow direction f, making it difficult for the fine particles to aggregate and preventing a decrease in laser transmittance. This improves the mass productivity and stability of the generation efficiency of fine particles related to the fine particle manufacturing apparatus 1.

[0140] Furthermore, according to this embodiment, the microparticle generation cell 2 has a first containment section 27a for containing the solution 7 (precursor solution 71), a partition wall 28a with an outlet hole through which the solution 7 (precursor solution 71) flows out from the first containment section 27a and through which a femtosecond pulse laser 30a is focused, and a second containment section 27b for containing the solution 7 (precursor solution 71) that has flowed out from the first containment section 27a through the outlet hole. As a result, the laser is reliably irradiated onto the flowing solution 7 (precursor solution 71), enabling the continuous production of microparticles. Also, after the start of microparticle generation, the generated microparticles flow in the flow direction f, making it difficult for the microparticles to aggregate and preventing a decrease in laser transmittance. This improves the mass productivity and stability of the generation efficiency of microparticles in the microparticle manufacturing apparatus 1. Furthermore, the generation region 32 can be optimized to match the shape of the outlet hole, and the energy of the laser light source can be suppressed. This makes it possible to reduce the labor involved in producing microparticles in the microparticle manufacturing apparatus 1.

[0141] Furthermore, according to this embodiment, the microparticle generation cell 2 has a pair of reflectors at both ends in the flow direction f that reflect the femtosecond pulse laser 30a. Therefore, the laser is reliably irradiated onto the flowing solution 7 (precursor solution 71), enabling the continuous production of microparticles. In addition, after the start of microparticle generation, the generated microparticles flow in the flow direction f, making it difficult for the microparticles to aggregate and preventing a decrease in laser transmittance. This improves the mass productivity and stability of the generation efficiency of microparticles in the microparticle manufacturing apparatus 1. Moreover, a wider generation area 32 can be formed within the microparticle generation cell 2 compared to when the laser is focused. This further improves the stability of the generation efficiency of microparticles in the microparticle manufacturing apparatus 1.

[0142] (Second Embodiment: Microparticle Manufacturing Apparatus 1) An example of the microparticle manufacturing apparatus 1 in this embodiment will be described with reference to the drawings. This embodiment differs from the first embodiment in that the input section 4 is connected to the microparticle generation cell 2 via an air tube 41f, and the microparticle manufacturing apparatus 1 further includes a surface modification section 8. The same configuration as described above will not be explained.

[0143] <Input Section 4> The input section 4 may have, for example, a path for transporting air into the microparticle generation cell 2 in addition to the flow path for the solution 7. The input section 4 is connected to the pressurized tank 41c and the microparticle generation cell 2 via a path that branches off from the air compressor 41a, as shown in Figure 7. Specifically, the air compressor 41a is connected to the pressurized tank 41c via one path that connects to an air tube 41b, a pipe branching joint 41d, an air tube 41e, a needle valve 45a, and a supply solenoid valve 46a. The air compressor 41a is also connected to the microparticle generation cell 2 via the other path that connects to an air tube 41b, a pipe branching joint 41d, a needle valve 45b, and a supply solenoid valve 46b.

[0144] When the input unit 4 pumps the precursor solution 71 from the pressurized tank 41c to the microparticle generation cell 2, it operates the supply solenoid valves 46a and 46b to open one path and transports compressed air generated by the air compressor 41a into the pressurized tank 41c, thereby supplying the solution 7 into the microparticle generation cell 2. Also, when the input unit 4 discharges the colloidal solution 72 from the microparticle generation cell 2, which has been irradiated with the femtosecond pulse laser 30a, it operates the supply solenoid valves 46a and 46b to open the other path and transports compressed air generated by the air compressor 41a into the microparticle generation cell 2, thereby discharging the solution 7 from the microparticle generation cell 2. In this case, since the colloidal solution 72 in the microparticle generation cell 2 is emptied before a new precursor solution 71 is introduced, compared to a batch-type microparticle manufacturing process that involves opening and closing known solenoid valves at the inlet 21 and outlet 22, the femtosecond pulse laser 30a can be reliably irradiated onto the precursor solution 71 that has not been irradiated with the femtosecond pulse laser 30a, making it easier to generate microparticles with a smaller particle size distribution. This improves the quality stability of the microparticles produced by the microparticle manufacturing apparatus 1.

[0145] <Surface Modification Unit 8> The surface modification unit 8 modifies the surface of the fine particles using a surface modifier. The surface modification unit 8 brings the fine particles generated in the fine particle generation cell 2 into contact with the surface modifier, and separates the surface-modified fine particles from the precursor (precursor solution 71). In this case, the generated fine particles can be continuously surface-modified, and only the surface-modified fine particles can be extracted and recovered. This improves the quality stability of the fine particles produced by the fine particle manufacturing apparatus 1.

[0146] The surface modification unit 8 includes, for example, a surface modifier supply tank 80, a surface modification waiting unit 82, an extraction solvent supply tank 83, and a separation tank 85.

[0147] The surface modifier supply tank 80 contains a known surface modifier 80a for surface-modifying fine particles. The surface modifier supply tank 80 is a known tank made of, for example, glass or a resin such as polypropylene or PFA (Per Fluoroalkoxy Alkane). The surface modifier supply tank 80 is connected to the fine particle generation cell 2 via a modifier tube 81 made of, for example, a resin such as polypropylene or silicone, and the surface modifier 80a is supplied into the fine particle generation cell 2 via the modifier tube 81.

[0148] The surface modification waiting area 82 is a region for bringing the fine particles and the surface modifier 80a into contact. The surface modification waiting area 82 can be a known tank made of, for example, glass or a resin such as polypropylene or PFA. The surface modification waiting area 82 is connected to, for example, the downstream end of the spectroscopic observation flow cell 51, and a mixture of fine particles (colloidal solution 72) and the surface modifier 80a (mixed solution 73) discharged from the spectroscopic observation flow cell 51 flows through its interior.

[0149] The extraction solvent supply tank 83 contains the extraction solvent 83a for separating surface-modified fine particles from surface-modified fine particles. The extraction solvent supply tank 83 can be a known tank made of, for example, glass or a resin such as polypropylene or PFA. The extraction solvent supply tank 83 is connected to the surface modification waiting unit 82 and the separation tank 85, for example, via a solution mixing unit 84.

[0150] The separation tank 85 is a region for separating surface-modified fine particles from surface-modified fine particles. The separation tank 85 can be a known tank made of, for example, glass or a resin such as polypropylene or PFA. The separation tank 85 is connected to the surface modification waiting section 82 and the extraction solvent supply tank 83 via a solution mixing section 84, which is made of, for example, glass or a resin such as polypropylene or PFA. A mixture of fine particles (colloidal solution 72) and surface modifier 80a discharged from the surface modifier supply tank 80 and the extraction solvent 83a discharged from the extraction solvent supply tank 83 flows into the separation tank 85 via the solution mixing section 84.

[0151] The separation tank 85 is connected to the recovery tank 61 via a solution tube 62, and the surface-modified fine particles are supplied to the recovery tank 61 via the solution tube 62. The separation tank 85 is connected to the pressurized tank 41c via a circulation pipe 86 made of the same material as the solution mixing unit 84, for example, and the surface-unmodified fine particles are supplied to the pressurized tank 41c via the circulation pipe 86.

[0152] (Second Embodiment: Method for Manufacturing Fine Particles) Next, with reference to the drawings, an example of the operation of the fine particle manufacturing apparatus 1 will be described as a method for manufacturing fine particles using the fine particle manufacturing apparatus 1 of this embodiment.

[0153] The operation method of the microparticle manufacturing apparatus 1 may further include, for example, a modification step. The operation method of the microparticle manufacturing apparatus 1 may include a modification step before or after at least one of the irradiation step and the analysis step.

[0154] <Preparation> Before the modification process, the operator places the surface modifier 80a, which will be supplied to the fine particle generation cell 2 in advance, into the surface modifier supply tank 80. The operator also places the extraction solvent 83a, which will be supplied to the separation tank 85 in advance, into the extraction solvent supply tank 83.

[0155] <Modification Process> In the modification process, the microparticle manufacturing apparatus 1 modifies the surface of the microparticles generated by the microparticle generation cell 2 by bringing the surface modifier 80a into contact with them, for example, via the surface modification section 8.

[0156] First, the surface modification unit 8 supplies a surface modifier 80a into the fine particle generation cell 2, for example, via a surface modifier supply tank 80. Here, the surface modifier supply tank 80 may supply the surface modifier 80a to the generation region 32 within the fine particle generation cell 2, or it may supply it upstream or downstream of the generation region 32.

[0157] Subsequently, the surface modification unit 8 brings the fine particles in the colloidal solution 72 into contact with the surface modifier 80a, for example, via the surface modification standby unit 82. Here, stirring within the surface modification standby unit 82 using a stirring bar (not shown) facilitates good contact between the fine particles and the surface modifier 80a.

[0158] Subsequently, the surface modification unit 8 discharges, for example, the colloidal solution 72 and the surface modifier 80a from the surface modification standby unit 82, and the extraction solvent 83a from the extraction solvent supply tank 83, and supplies the mixed solution 73 mixed in the solution mixing unit 84 to the separation tank 85.

[0159] In this separation tank 85, surface-modified microparticles with the surface modifier 80a, unreacted precursors, extraction solvent 83a, and the solvent (extraction solvent) contained in the precursor solution 71 or colloidal solution 72 are present. The surface-modified microparticles have the extraction solvent 83a bound to their surface, and as a result, they float to the top of the separation tank 85 as the microparticle-containing organic solvent 74. This is because the formation of a surface modification layer on the surface of the microparticles improves their affinity for the extraction solvent compared to the surface of the microparticles, causing them to float to the upper extraction solvent layer in the separation tank 85. On the other hand, the unreacted precursors remain in the extraction solvent and are separated from the upper extraction solvent layer (microparticle-containing organic solvent 74) as the precursor-containing organic solvent 75.

[0160] The surface modifier 80a and the extraction solvent 83a may be arbitrarily selected according to the properties of the precursor solution 71. For example, when the precursor in the precursor solution 71 is a water-soluble salt and a polar solvent such as water is used as the solvent to be extracted, an alkanethiol having a binding site for fine particles and a hydrophobic group, such as 1-dodecanethiol, is used as the surface modifier 80a, and a nonpolar solvent such as hexane is used as the extraction solvent 83a. In this case, the surface-modified fine particles move from the solvent to be extracted layer to the extraction solvent layer by binding with the extraction solvent 83a, which is a nonpolar solvent, because the alkanethiol on the surface has a higher affinity for the nonpolar solvent than for the polar solvent. Also, for example, when the precursor in the precursor solution 71 is an insoluble salt and a nonpolar solvent such as hexane is used as the solvent to be extracted, thioglucose is used as the surface modifier 80a, and a polar solvent such as water is used as the extraction solvent 83a. In this case, the surface-modified fine particles move from the solvent to be extracted layer to the extraction solvent layer by binding with the extraction solvent 83a, which is a polar solvent, because the thioglucose on the surface has a higher affinity for the polar solvent than for the nonpolar solvent. As a result, the fine particles surface-modified with the surface modifier 80a are separated from the precursor or the precursor solution 71.

[0161] Subsequently, the surface modification unit 8 supplies only the surface-modified fine particles to the recovery tank 61, for example, via the separation tank 85. In this case, the generated fine particles can be continuously surface-modified, and only the surface-modified fine particles can be extracted and recovered. This improves the quality stability of the fine particles produced by the fine particle manufacturing apparatus 1.

[0162] On the other hand, the unmodified fine particles do not have the extraction solvent 83a bound to their surface and consequently settle at the bottom of the separation tank 85. Subsequently, the surface modification unit 8 supplies the unmodified fine particles to the pressurized tank 41c, for example, via the circulation piping 86.

[0163] The above steps complete the production of the fine particles and the colloidal solution 72 in this embodiment.

[0164] According to this embodiment, the device further includes a surface modification unit 8 that brings the microparticles generated in the microparticle generation cell 2 into contact with a surface modifier 80a, and separates the surface-modified microparticles from a precursor (precursor solution 71). Therefore, the generated microparticles can be continuously surface-modified, and only the surface-modified microparticles can be extracted and recovered. This improves the quality stability of the microparticles produced by the microparticle manufacturing apparatus 1.

[0165] (Method for manufacturing the microparticle generation cell 2) Next, with reference to the drawings, an example of a method for manufacturing the microparticle generation cell 2 that constitutes the microparticle manufacturing apparatus 1 of the above-described embodiment will be explained. In the following, an example of a method for manufacturing the microparticle generation cell 2 shown in Figure 4(b) will be explained.

[0166] First, the operator attaches the processing material 2' to the position of the microparticle generation cell 2 in the microparticle manufacturing apparatus 1, corresponding to Figure 1, as shown in Figure 8(a), for example. The processing material 2' is made of the same material as the microparticle generation cell 2, for example, resin. The shape of the processing material 2' is, for example, similar to Figure 4(b), having a first housing section 27a, a second housing section 27b, and a reduced diameter section 28, with a partition wall 28b formed in the reduced diameter section 28 that completely separates the first housing section 27a and the second housing section 27b. At this time, the solution 7 in the first housing section 27a does not flow into the second housing section 27b.

[0167] Subsequently, the operator focuses the femtosecond pulse laser 30b onto the partition wall 28b via the irradiation device 30 and lens 31' to form an irradiation area 32b. As a result, the partition wall 28b is perforated with an outflow hole 28c, as shown in Figure 8(b), for example. At this time, the solution 7 in the first containment section 27a can flow out to the second containment section 27b through the outflow hole 28c.

[0168] Furthermore, as shown in Figure 8(c), for example, the femtosecond pulse laser 30a irradiated from the irradiation device 30 to generate microparticles in the microparticle generation cell 2 is focused onto the outflow hole 28c to form a microparticle generation region 32a. In this case, the laser is reliably irradiated onto the flowing solution 7, enabling the production of a cell for continuously manufacturing microparticles. Also, after the start of microparticle generation, the generated microparticles flow in the flow direction f, making it difficult for the microparticles to aggregate and preventing a decrease in laser transmittance. This improves the mass productivity and stability of the generation efficiency of microparticles in the microparticle manufacturing apparatus 1. Moreover, the generation region 32a can be optimized to match the shape of the outflow hole 28c, allowing for the suppression of the laser light source energy. This reduces the labor required for microparticle production in the microparticle manufacturing apparatus 1.

[0169] The generation region 32a is a region that generates fine particles, similar to the generation region 32. The irradiation region 32b is a region where energy is generated to create an outflow hole 28c in the partition wall 28b, and it encompasses the generation regions 32 and 32a. It is preferable that the irradiation region 32b is larger than the generation regions 32 and 32a, because components of the partition wall 28b are less likely to be mixed into the colloidal solution 72 as impurities.

[0170] Lens 31' is, for example, a lens similar to lens 31. When forming an illumination area 32b that is larger than the generation area 32a, lens 31' may be a lens with different optical conditions than lens 31.

[0171] The femtosecond pulsed laser 30b is irradiated under the same irradiation conditions as the femtosecond pulsed laser 30a, for example. The femtosecond pulsed laser 30b may be irradiated under different irradiation conditions than the femtosecond pulsed laser 30a when, for example, the energy required to drill the outflow hole 28c in the partition wall 28b is different from the energy required to generate fine particles. In this case, the laser output used for drilling the outflow hole 28c or generating fine particles can be optimized. This makes it possible to reduce the labor involved in producing fine particles in the fine particle manufacturing apparatus 1.

[0172] The above process completes the manufacturing of the microparticle generation cell 2 shown in Figure 4(b).

[0173] According to this embodiment, the manufacturing method for the microparticle generation cell 2 involves irradiating a femtosecond pulsed laser 30b onto a partition wall 28b separating a first containment section 27a and a second containment section 27b, which are adjacent to each other and contain a solution 7. This causes the solution 7 to flow out of the first containment section 27a and creates an outflow hole 28c into which the femtosecond pulsed laser 30a is focused. As a result, the laser is reliably irradiated onto the flowing solution 7, enabling the production of a cell for continuously generating microparticles. Furthermore, after the start of microparticle generation, the generated microparticles flow in the flow direction f, making it difficult for the microparticles to aggregate and preventing a reduction in laser transmittance. This improves the mass productivity and stability of the generation efficiency of microparticles in the microparticle manufacturing apparatus 1. Moreover, the generation region 32a can be optimized to match the shape of the outflow hole 28c, and the energy of the laser light source can be suppressed. This reduces the labor required for microparticle production in the microparticle manufacturing apparatus 1.

[0174] While several embodiments of the present invention have been described, these embodiments are presented as examples only and are not intended to limit the scope of the invention. These novel embodiments can be carried out in a variety of other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their variations are included in the scope and spirit of the invention, as well as in the claims of the invention and its equivalents.

[0175] 1. Microparticle Manufacturing Apparatus 10. Housing 101. CPU 102. ROM 103. RAM 104. Storage Unit 105-107. I / F 108. Input Unit 109. Display Unit 110. Internal Bus 2. Microparticle Generation Cell 20. Main Body 21. Inlet 22. Outlet 23. Irradiation Plate 24. Fixing Member 25. Observation Window 26. Window Fixing Member 27. Reference Unit 28. Diameter Reduction Unit 28a, 28b. Partition Wall 28c. Outlet Hole 2'. Processing Material 3. Irradiation Unit 30. Irradiation Device 30a, 30b. Femtosecond Pulse Laser 31. Lens 32, 32a. Generation Area 32b. Irradiation Area 33-36. Reflection Unit 4. Input Unit 41a. Air Compressor 41b. Air Tube 41c. Pressurized Tank 41d Pipe branching joint 41e, 41f Air tube 42a Magnetic stirrer 42b Stirring bar 43, 43a-43d Solution tube 44 Different diameter adapter 45, 45a, 45b Needle valve 46a, 46b Supply solenoid valve 5 Analysis section 51 Flow cell for spectroscopic observation 52 Solution tube 53 Spectrometer 53a White light 54 Irradiation device 54a Nanosecond pulsed laser 55 Lens 56 Spectrometer 57 Lens 6 Recovery section 61 Recovery tank 62 Solution tube 7 Solution 71 Precursor solution 72 Fine particle colloid solution 73 Mixed solution 74 Fine particle-containing organic solvent 75 Precursor-containing organic solvent 8 Surface modification section 80 Surface modifier supply tank 80a Surface modifier 81 Modifier tube 82 Surface modification waiting section 83 Extraction solvent supply tank 83a Extraction solvent 84 Solution mixing section 85 Separation tank 86 Circulation piping 9 Communication network f Flow direction

Claims

1. A microparticle manufacturing apparatus for producing microparticles by irradiating a solution containing a precursor with a metal atom with a femtosecond pulse laser, comprising: a microparticle generation cell extended in the direction of flow of the solution; and an irradiation unit that irradiates the solution flowing within the microparticle generation cell with the femtosecond pulse laser along the direction of flow.

2. The microparticle manufacturing apparatus according to claim 1, wherein the microparticle generating cell comprises: a first containment section for containing the solution; a partition wall adjacent to the downstream end of the first containment section in the flow direction, having an outflow hole through which the solution flows out of the first containment section and through which the femtosecond pulse laser is focused by the irradiation section; and a second containment section adjacent to the downstream end of the partition wall in the flow direction, for containing the solution that has flowed out of the first containment section through the outflow hole.

3. The microparticle manufacturing apparatus according to claim 2, characterized in that the inner circumferential surface of the first housing portion of the microparticle generation cell is reduced in diameter as it approaches the partition wall.

4. The microparticle manufacturing apparatus according to claim 1, characterized in that the microparticle generation cell has a pair of reflectors at both ends in the flow direction that reflect the femtosecond pulse laser irradiated in the flow direction by the irradiation unit.

5. The microparticle manufacturing apparatus according to claim 1, further comprising an analysis unit for analyzing the components of the microparticles generated in the microparticle generation cell by laser-induced breakdown spectroscopy.

6. The microparticle manufacturing apparatus according to claim 5, characterized in that the analysis unit uses a laser branched from the femtosecond pulse laser irradiated by the irradiation unit as its excitation source.

7. The microparticle manufacturing apparatus according to claim 5, characterized in that the analysis unit uses the femtosecond pulse laser irradiated into the microparticle generation cell by the irradiation unit as an excitation source to perform component analysis on the microparticles in the microparticle generation cell.

8. The microparticle manufacturing apparatus according to any one of claims 1 to 7, further comprising a surface modification unit that brings the microparticles generated in the microparticle generation cell into contact with a surface modifier and separates the surface-modified microparticles from the precursor.

9. A method for producing fine particles by irradiating a solution containing a precursor with metal atoms with a femtosecond pulse laser, the method comprising an irradiation step of irradiating the solution, which is flowing in a cell for generating fine particles that extends in the direction of the flow of the solution, with the femtosecond pulse laser along the direction of the flow.

10. A microparticle generating cell used in a microparticle manufacturing apparatus for producing microparticles by irradiating a solution containing a precursor mixed with metal atoms with a femtosecond pulse laser, the cell being extended in the direction of the flow of the solution and irradiated with the solution flowing inside along the direction of the flow, the cell comprising: a first containment section for containing the solution; a partition wall adjacent to the first containment section in the direction of the flow, with an outflow hole drilled therein for allowing the solution to flow out of the first containment section and for focusing the femtosecond pulse laser; and a second containment section adjacent to the partition wall in the direction of the flow, for containing the solution that has flowed out of the first containment section through the outflow hole.

11. A microparticle production apparatus for producing microparticles by irradiating a solution containing a precursor with metal atoms with a femtosecond pulse laser, the microparticle production cell being extended in the direction of the flow of the solution and irradiating the solution flowing inside with the femtosecond pulse laser along the direction of the flow, the microparticle production cell having a pair of reflectors at both ends in the direction of the flow that reflect the femtosecond pulse laser irradiated in the direction of the flow by the irradiation unit.

12. A method for manufacturing a microparticle generation cell used in a microparticle manufacturing apparatus for manufacturing microparticles by irradiating a solution containing a precursor mixed with metal atoms with a femtosecond pulse laser, the cell being extended in the direction of the flow of the solution and having the femtosecond pulse laser irradiated along the direction of the flow of the solution flowing inside, characterized in that the femtosecond pulse laser is irradiated onto a partition wall separating a first housing section and a second housing section that contain the solution and are adjacent to each other in the direction of the flow, thereby causing the solution to flow out of the first housing section and creating an outflow hole into which the femtosecond pulse laser is focused.

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