Device for liquid-phase laser fragmentation and liquid-phase laser fragmentation apparatus

Abstract

To improve emission uniformity of a laser beam to metal fine particulates.SOLUTION: An LFL device 2 comprises a device body 21 and an ultrasonic wave applying part 22. The ultrasonic wave applying part 22 is installed to the device body 21. An internal flow path 24 through which metal particle dispersion liquid 91, in which metal fine particulates are dispersed into liquid, flows, is provided inside the device body 21. The ultrasonic wave applying part 22 applies an ultrasonic wave to the metal particle dispersion liquid 91 flowing through the internal flow path 24. An external surface of the device body 21 is provided with a translucent part 25 through which a laser beam emitted to the metal particle dispersion liquid 91 in the internal flow path 24, to which the ultrasonic wave has been applied by the ultrasonic wave applying part 22, passes. This can improve emission uniformity of the laser beam to metal fine particulates.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to devices and apparatus for the liquid phase laser fragmentation of metal particles. [Background technology]

[0002] In recent years, liquid-phase laser ablation has been used as a method for producing metal microparticles, which are fine particles of metals or metal compounds, by irradiating a target in a liquid with a laser to perform laser ablation. For example, Patent Document 1 proposes a liquid-phase laser ablation device that produces metal microparticles by placing a metal material at the bottom of a flask in which a solvent such as ethanol is stored, and irradiating the metal material with a laser that has passed through the bottom of the flask. Patent Document 2 also proposes a technology for miniaturizing metal microparticles by irradiating metal microparticles in a liquid phase stored in an acrylic container with a pulsed laser. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2011-161379 A [Patent Document 2] JP 2020-176288 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the device of Patent Document 2, the metal particles suspended in the liquid phase stored in the acrylic container are irradiated with a pulsed laser, so there is a risk that the laser irradiation of the metal particles may be non-uniform due to the density of the metal particles in the liquid phase, etc. As a result, the particle size of the fine metal particles after the laser irradiation may also be non-uniform.

[0005] The present invention has been made in consideration of the above problems, and has an object to improve the uniformity of laser light irradiation onto metal microparticles. [Means for solving the problem]

[0006] A first aspect of the present invention is a device for liquid-phase laser fragmentation, comprising a device body and an ultrasound application unit attached to the device body. An internal flow path is provided inside the device body through which a metal particle dispersion liquid in which metal microparticles are dispersed flows. The ultrasound application unit applies ultrasound to the metal particle dispersion liquid flowing through the internal flow path. An outer surface of the device body is provided with a light-transmitting unit through which laser light passes to be irradiated to the metal particle dispersion liquid in the internal flow path to which ultrasound has been applied by the ultrasound application unit.

[0007] A second aspect of the present invention is the device for liquid-phase laser fragmentation of the first aspect, wherein the device body includes a supply port located at an upstream end of the internal flow path and through which the metal particle dispersion is supplied, and a discharge port located at a downstream end of the internal flow path and through which the metal particle dispersion irradiated with the laser light that has transmitted through the light-transmitting portion is discharged. The internal flow path includes a light-receiving portion that is irradiated with the laser light that has transmitted through the light-transmitting portion. Ultrasonic waves are applied to the metal particle dispersion by the ultrasound application portion between the supply port and the light-receiving portion of the internal flow path.

[0008] A third aspect of the present invention is the device for liquid-phase laser fragmentation of the first aspect (which may be either the first or second aspect), in which the internal flow path includes a light-receiving section that is irradiated with the laser light that has passed through the light-transmitting section. The light-receiving section extends in the vertical direction. The flow of the metal particle dispersion liquid in the light-receiving section is from the bottom to the top.

[0009] A fourth aspect of the present invention is the device for liquid phase laser fragmentation of the first aspect (which may be any one of the first to third aspects), wherein the internal flow path includes a light receiving section to which the laser light transmitted through the light transmitting section is irradiated. The direction of incidence of the laser light on the light receiving section is parallel to the thickness direction of the device body. The thickness of the device body is smaller than the size of the device body in the vertical and horizontal directions perpendicular to the thickness direction.

[0010] A fifth aspect of the present invention is the liquid-phase laser fragmentation device of the first aspect (which may be any one of the first to fourth aspects), wherein the internal flow path includes a light-receiving portion to which the laser light that has passed through the light-transmitting portion is irradiated. The direction of incidence of the laser light on the light-receiving portion is parallel to the thickness direction of the device body. The liquid-phase laser fragmentation device further includes a flow path thickness changing portion that changes the thickness of the light-receiving portion in the thickness direction.

[0011] A sixth aspect of the present invention is a device for liquid-phase laser fragmentation of the fifth aspect, further comprising a light transmittance measuring unit that measures the light transmittance of the metal particle dispersion in the light receiving unit, and a control unit that drives the flow path thickness changing unit based on an output from the light transmittance measuring unit.

[0012] A seventh aspect of the present invention is a liquid-phase laser fragmentation apparatus comprising a liquid-phase laser fragmentation device according to any one of aspects 1 to 6, a dispersion supply section that supplies the metal particle dispersion to the internal flow path of the liquid-phase laser fragmentation device, a light source section that emits laser light toward the light-transmitting section of the liquid-phase laser fragmentation device, and a dispersion recovery section that recovers the metal particle dispersion discharged from the internal flow path of the liquid-phase laser fragmentation device. Effect of the Invention

[0013] According to the present invention, it is possible to improve the uniformity of laser light irradiation onto metal fine particles. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a front view of an LFL device according to a first embodiment. [Diagram 2] FIG. 2 is a side view of the LFL device. [Diagram 3] FIG. 11 is a vertical cross-sectional view of an LFL device according to a second embodiment. [Figure 4] FIG. 1 illustrates a configuration of a computer. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] FIG. 1 is a front view showing the configuration of a liquid-phase laser fragmentation apparatus 1 according to a first embodiment of the present invention. FIG. 2 is a side view showing the configuration of the liquid-phase laser fragmentation apparatus 1. In FIG. 1 and FIG. 2, three mutually orthogonal directions are indicated by arrows as the X direction, the Y direction, and the Z direction. In the example shown in FIG. 1 and FIG. 2, the X direction and the Y direction are horizontal directions perpendicular to each other, and the Z direction is a vertical direction. In FIG. 1 and FIG. 2, for convenience of illustration, a part of the configuration of the liquid-phase laser fragmentation apparatus 1 is omitted. In FIG. 2, a part of the configuration of the liquid-phase laser fragmentation apparatus 1 is shown in a cross section perpendicular to the X direction.

[0016] The liquid-phase laser fragmentation apparatus 1 is an apparatus that performs laser fragmentation in liquid (LFL) in which metal particles dispersed in a liquid are irradiated with a laser beam to reduce the metal particles to smaller particles. In the following description, the liquid-phase laser fragmentation apparatus 1 is also referred to as the "LFL apparatus 1." The above-mentioned metal particles are any one of fine particles of a simple metal, fine particles of a metal compound (e.g., a metal oxide, etc.), and fine particles of an alloy. Alternatively, the metal particles may be a mixture of two or more of fine particles of a simple metal, fine particles of a metal compound, and fine particles of an alloy.

[0017] The LFL apparatus 1 includes a liquid phase laser fragmentation device 2 (hereinafter also referred to as "LFL device 2"), a dispersion liquid supply unit 3, a dispersion liquid recovery unit 4, and a light source unit 7. The dispersion liquid supply unit 3 holds a metal particle dispersion liquid 91 and supplies the metal particle dispersion liquid 91 to the LFL device 2. The metal particle dispersion liquid 91 is a dispersion of the above-mentioned metal fine particles in a liquid solvent. In FIG. 1, the metal particle dispersion liquid 91 is indicated with parallel diagonal lines to facilitate understanding of the drawing.

[0018] The solvent of the metal particle dispersion liquid 91 is, for example, glycerin, ethanol, isopropanol, etc. The metal fine particles are, for example, particles of a simple metal such as silver (Ag) whose surfaces are coated with a protective agent. The protective agent is, for example, an organic polymer compound such as polyvinylpyrrolidone (PVP), polyethylene glycol (PEG), or polyvinyl alcohol (PVA).

[0019] The average particle size of the metal microparticles in the metal particle dispersion liquid 91 held in the dispersion liquid supply unit 3 is, for example, 200 nm or less, and preferably 100 nm or less. The lower limit of the average particle size is not particularly limited, but is, for example, 50 nm or more. The average particle size is determined by observing 300 or more metal microparticles in a field of view using an electron microscope, and taking the arithmetic average of the particle sizes of 150 or more metal microparticles among them. The type and average particle size of the metal microparticles, as well as the type of protective agent, may be changed in various ways. In addition, the protective agent may be omitted.

[0020] The dispersion liquid supply unit 3 includes a supply container 31, a supply pipe 32, and a liquid delivery unit 33. The supply container 31 stores the metal particle dispersion liquid 91 before being supplied to the LFL device 2. The supply container 31 is, for example, a graduated cylinder, a flask, a test tube, or a beaker. The supply pipe 32 connects the supply container 31 and the LFL device 2. The supply pipe 32 is, for example, a flexible pipe made of resin. The supply pipe 32 is, for example, a transparent pipe. The liquid delivery unit 33 is provided on the supply pipe 32 between the supply container 31 and the LFL device 2. The liquid delivery unit 33 delivers the metal particle dispersion liquid 91 stored in the supply container 31 to the LFL device 2 through the supply pipe 32. The liquid delivery unit 33 is, for example, an axial flow type or centrifugal type pump. The shapes, materials, and structures of the supply container 31, the supply pipe 32, and the liquid delivery unit 33 may be variously changed. Furthermore, the structure of the dispersion liquid supply unit 3 may also be modified in various ways.

[0021] The LFL device 2 is a member (so-called reactor) through which the metal particle dispersion liquid 91 supplied from the dispersion liquid supply unit 3 passes. The LFL device 2 is configured so that the metal particle dispersion liquid 91 flowing inside can be irradiated with laser light from the light source unit 7. In the example shown in Figs. 1 and 2, the LFL device 2 is a substantially plate-like or substantially rectangular parallelepiped member that is thin in the Y direction. The shape of the LFL device 2 when viewed from the front (i.e., the shape when viewed along the Y direction) is, for example, substantially rectangular. The detailed structure of the LFL device 2 will be described later.

[0022] In the LFL apparatus 1, a metal particle dispersion liquid 91 flowing inside the LFL device 2 is irradiated with laser light from a light source unit 7. The light source unit 7 includes a laser light source 71 and a galvanometer scanner 72. The laser light source 71 is, for example, a laser oscillator that emits pulsed laser light having a pulse width of 80 femtoseconds to 2 microseconds and a wavelength of 19 nm to 10.6 μm. The energy per pulse of the pulsed laser light is, for example, 50 μJ to 5 J. Note that the type of laser light emitted from the laser light source 71 and the above-mentioned characteristics may be changed in various ways.

[0023] The laser light emitted from the laser light source 71 is guided to the galvano scanner 72. The galvano scanner 72 includes a galvano mirror and a galvano motor, and reflects the laser light emitted from the laser light source 71 and guides it to the LFL device 2. The laser light reflected by the galvano scanner 72 is guided substantially parallel to the Y direction and enters the LFL device 2. The irradiation position of the laser light on the LFL device 2 is scanned by the galvano scanner 72. As a result, the laser light is irradiated onto a predetermined area (hereinafter, also referred to as a "scanning area 70") on the LFL device 2. In FIG. 1, the scanning area 70 is surrounded by a two-dot chain line. In the example shown in FIG. 1, the scanning area 70 is located substantially at the center of the LFL device 2, and the shape of the scanning area 70 is substantially rectangular. The shape of the scanning area 70 may be changed in various ways. In addition, the structure of the light source unit 7 may also be changed in various ways. For example, instead of the galvano scanner 72, another configuration for scanning the laser light may be provided.

[0024] In the LFL device 2, a part of the internal flow path 24 (described later) through which the metal particle dispersion liquid 91 flows is included in the above-mentioned scanning region 70, and the laser light from the light source unit 7 is irradiated onto the metal particle dispersion liquid 91 flowing through the internal flow path 24. This causes the metal fine particles dispersed in the metal particle dispersion liquid 91 to be micronized. The metal particle dispersion liquid 91 containing the micronized metal fine particles is discharged from the LFL device 2 and collected by the dispersion liquid recovery unit 4. The dispersion liquid recovery unit 4 includes a recovery container 41 and a recovery pipe 42. The recovery container 41 recovers and stores the metal particle dispersion liquid 91 discharged from the LFL device 2 via the recovery pipe 42. The recovery container 41 is, for example, a graduated cylinder, a flask, a test tube, or a beaker. The recovery pipe 42 connects the recovery container 41 and the LFL device 2. The recovery pipe 42 is, for example, a flexible pipe made of resin. The recovery pipe 42 is, for example, a transparent pipe. The shapes, materials, and structures of the recovery container 41 and the recovery pipe 42 may be modified in various ways. The structure of the dispersion liquid recovery unit 4 may also be modified in various ways. For example, the above-mentioned liquid delivery unit 33 may be provided on the recovery pipe 42 in the dispersion liquid recovery unit 4, instead of in the dispersion liquid supply unit 3.

[0025] The LFL device 2 includes a device body 21 and an ultrasonic wave application unit 22. The device body 21 is a substantially plate-like or substantially rectangular parallelepiped member that is thin in the Y direction. In other words, the thickness of the device body 21 in the Y direction (i.e., thickness direction) is smaller than the size of the device body 21 in the Z direction and the X direction (i.e., vertical direction and horizontal direction). The thickness of the device body 21 in the Y direction is, for example, 0.1 mm to 10 mm. The width of the device body 21 in the X direction is, for example, 1 mm to 300 mm. The height of the device body 21 in the Z direction is, for example, 1 mm to 300 mm. The size and shape of the device body 21 may be changed in various ways.

[0026] The device body 21 includes a frame 231 and two light-transmitting members 232. The frame 231 is a substantially rectangular frame-shaped member with a substantially rectangular opening in the center when viewed from the front. Each of the two light-transmitting members 232 is a substantially rectangular translucent member when viewed from the front. The light-transmitting member 232 is, for example, a transparent, substantially flat plate-shaped member that extends substantially perpendicularly to the Y direction. The two light-transmitting members 232 are fitted into the openings of the frame 231 and attached to the frame 231. The two light-transmitting members 232 are disposed to face each other in the Y direction while being spaced apart from each other.

[0027] Each light-transmitting member 232 is connected to the frame 231 by a connecting member 233 having a substantially rectangular frame shape in a front view. The connecting member 233 is a substantially flat plate-shaped member covering substantially the entire outer periphery of the light-transmitting member 232 in a front view. The frame 231 and the connecting member 233 are made of, for example, resin. Each light-transmitting member 232 is made of, for example, quartz glass. The materials and shapes of the frame 231, the light-transmitting member 232, and the connecting member 233 may be changed in various ways. The light-transmitting member 232 may be a translucent member.

[0028] 1 and 2, connecting member 233 is a member that does not have light-transmitting properties (i.e., is opaque). In LFL device 2, the portion of light-transmitting member 232 that is exposed from connecting member 233 (i.e., the portion excluding the outer peripheral edge portion) becomes light-transmitting section 25 that is capable of transmitting laser light from light source section 7. In the example shown in Fig. 2, LFL device 2 has light-transmitting section 25 on the outer surface on the (-Y) side and the outer surface on the (+Y) side.

[0029] Between the two light-transmitting members 232 in the Y direction, two sidewall members 234 are arranged side by side in the X direction while being spaced apart from each other. Each of the two sidewall members 234 is a light-transmitting member that is substantially rectangular in a front view. The sidewall member 234 is, for example, a transparent, substantially plate-like member that extends substantially perpendicularly to the Y direction. Each sidewall member 234 is sandwiched and fixed by the two light-transmitting members 232 from the (+Y) side and the (-Y) side.

[0030] Between the two sidewall members 234 in the X direction, a substantially rectangular gap that is long in the Z direction in front view is provided, and the gap is sandwiched by two light-transmitting members 232 from the (+Y) side and the (-Y) side to form a light-transmitting flow path 241 that extends substantially parallel to the Z direction. The cross section of the light-transmitting flow path 241 perpendicular to the Z direction is substantially rectangular, and has substantially the same shape over substantially the entire length of the light-transmitting flow path 241. The periphery (i.e., the (+X) side, the (+Y) side, the (-X) side, and the (-Y) side) of the light-transmitting flow path 241 provided inside the device body 21 is surrounded by the light-transmitting members 232 and the sidewall members 234, which are members having light transmission properties. The portion of the light-transmitting flow path 241 included in the above-mentioned scanning region 70 (i.e., the portion overlapping the scanning region 70 in front view) is the light-receiving unit 240 that is irradiated with the laser light emitted from the light source unit 7 and transmitted through the light-transmitting unit 25. In the example shown in FIG. 1, the light receiving section 240 is a portion of the light-transmitting flow path 241 excluding the upper and lower ends.

[0031] As described above, the laser light reflected by the galvano scanner 72 is guided to the light-transmitting section 25 of the LFL device 2 and enters the LFL device 2 approximately parallel to the Y direction (i.e., approximately perpendicular to the (-Y) side outer surface of the (-Y) side light-transmitting member 232). In other words, the incident direction of the laser light on the light-receiving section 240 is approximately parallel to the thickness direction of the device body 21. In the example shown in FIG. 1, the light-receiving section 240 extends approximately parallel to the Z direction (i.e., the up-down direction).

[0032] A lower end (i.e., an end on the (-Z) side) of the light-transmitting flow path 241 is connected to a first flow path 242 provided at the lower part of the frame 231. The first flow path 242 is a flow path that penetrates the inside of the frame 231 at the lower part of the frame 231. The first flow path 242 extends in the (-Z) direction from the lower end of the light-transmitting flow path 241, bends to the (+X) side at a bend part 243, and then extends approximately parallel to the (+X) direction. An end on the (+X) side of the first flow path 242 is connected to a supply pipe 32 of the dispersion liquid supply unit 3 via a supply port 261 provided on a side surface on the (+X) side of the device body 21.

[0033] An upper end (i.e., an end on the (+Z) side) of the light-transmitting flow path 241 is connected to a second flow path 244 provided on the upper part of the frame 231. The second flow path 244 is a flow path that penetrates the inside of the frame 231 at the upper part of the frame 231. The second flow path 244 extends in the (+Z) direction from the upper end of the light-transmitting flow path 241, bends to the (-X) side at a bending part 245, and then extends approximately parallel to the (-X) direction. An end on the (-X) side of the second flow path 244 is connected to a recovery pipe 42 of the dispersion liquid recovery unit 4 via a discharge port 262 provided on the side surface on the (-X) side of the device body 21.

[0034] In the following description, the first flow path 242, the light-transmitting flow path 241, and the second flow path 244 provided inside the LFL device 2 are also collectively referred to as the "internal flow path 24." In the LFL apparatus 1, the metal particle dispersion liquid 91 supplied from the dispersion liquid supply unit 3 to the inside of the LFL device 2 (i.e., the internal flow path 24) via the supply port 261 passes through the first flow path 242 of the internal flow path 24, reaches the lower end of the light-transmitting flow path 241, and flows upward from the lower end of the light-transmitting flow path 241. The metal particle dispersion liquid 91 flows from the upper end of the light-transmitting flow path 241 into the second flow path 244, passes through the second flow path 244, and is discharged to the outside of the LFL device 2 (i.e., from the internal flow path 24) via the discharge port 262. The metal particle dispersion liquid 91 discharged from the internal flow path 24 is collected by the dispersion liquid recovery unit 4. The above-mentioned supply port 261 is located at the upstream end of the internal flow path 24 in the device body 21, and the discharge port 262 is located at the downstream end of the internal flow path 24.

[0035] The ultrasonic wave applying unit 22 is attached to the device body 21 near the internal flow path 24. In the example shown in FIG. 1, the ultrasonic wave applying unit 22 is attached to the center in the X direction at the lower end of the device body 21. The ultrasonic wave applying unit 22 includes an ultrasonic transducer 221 and a horn 222. The ultrasonic transducer 221 converts high-frequency power into ultrasonic waves. The ultrasonic transducer 221 is, for example, a substantially cylindrical or substantially disk-shaped member. The horn 222 is fixed to the upper surface of the ultrasonic transducer 221 and is disposed below the bent portion 243 in the vicinity of the bent portion 243 of the first flow path 242 of the internal flow path 24. The horn 222 is formed of a metal such as stainless steel.

[0036] Horn 222 includes a substantially disk-shaped horn lower portion and a substantially cylindrical horn upper portion protruding upward from the center of the upper surface of the horn lower portion. The upper end of the horn upper portion is disposed close to bent portion 243 of first flow path 242. Horn 222 transmits ultrasonic waves generated by ultrasonic transducer 221 to internal flow path 24 and applies the ultrasonic waves to metal particle dispersion liquid 91 flowing through internal flow path 24. In the example shown in FIG. 1, ultrasonic waves are applied to metal particle dispersion liquid 91 in first flow path 242 located between supply port 261 and light-transmitting flow path 241. In other words, ultrasonic waves are applied to metal particle dispersion liquid 91 between supply port 261 and light-receiving unit 240 of internal flow path 24. The frequency of ultrasonic waves applied to metal particle dispersion liquid 91 by ultrasonic wave applying unit 22 is, for example, 20 Hz to 1000 kHz.

[0037] In the LFL device 1, ultrasonic waves are applied to the metal particle dispersion liquid 91, thereby improving the dispersibility of the metal microparticles in the metal particle dispersion liquid 91. In other words, the application of ultrasonic waves causes the metal microparticles to be approximately uniformly dispersed in the metal particle dispersion liquid 91. In other words, the application of ultrasonic waves suppresses position-dependent variation in the density of the metal microparticles dispersed in the metal particle dispersion liquid 91.

[0038] In the LFL apparatus 1, the metal particle dispersion 91 to which ultrasonic waves have been applied by the ultrasonic application unit 22 (i.e., the metal particle dispersion 91 containing metal microparticles with improved dispersibility) flows from the bottom to the top in the light-transmitting flow path 241, and the metal particle dispersion 91 is irradiated with the above-mentioned laser light transmitted through the light-transmitting unit 25 at the light-receiving unit 240. As a result, the laser light is irradiated approximately evenly onto a large number of metal microparticles dispersed in the metal particle dispersion 91, and the large number of metal microparticles are micronized approximately evenly. As a result, in the metal particle dispersion 91 that passes through the LFL device 2 and is recovered by the dispersion recovery unit 4, the uniformity of the particle size of the micronized metal microparticles contained in the metal particle dispersion 91 is improved.

[0039] The average particle size of the metal microparticles in the metal particle dispersion 91 recovered in the dispersion recovery unit 4 (i.e., the metal microparticles after micronization) is, for example, 10 nm or less, and preferably 5 nm or less. There is no particular restriction on the lower limit of the average particle size, but it is, for example, 2 nm or more. The average particle size is determined in the same manner as the average particle size of the metal microparticles in the metal particle dispersion 91 held in the dispersion supply unit 3 described above (i.e., the metal microparticles before micronization).

[0040] As described above, the LFL device 2 includes the device body 21 and the ultrasound application unit 22. The ultrasound application unit 22 is attached to the device body 21. An internal flow path 24 is provided inside the device body 21, through which a metal particle dispersion liquid 91 in which metal fine particles are dispersed in a liquid flows. The ultrasound application unit 22 applies ultrasound to the metal particle dispersion liquid 91 flowing through the internal flow path 24. A light-transmitting unit 25 through which a laser beam passes is provided on the outer surface of the device body 21. The laser beam is irradiated to the metal particle dispersion liquid 91 in the internal flow path 24 to which ultrasound has been applied by the ultrasound application unit 22.

[0041] In the LFL device 2, as described above, the application of ultrasonic waves improves the dispersibility of the metal microparticles in the metal particle dispersion liquid 91, and therefore the uniformity of the laser light irradiation of the metal microparticles can be improved. As a result, the uniformity of the particle size of the metal microparticles after being refined by the laser light irradiation can be improved.

[0042] As described above, the device body 21 includes the supply port 261 located at the upstream end of the internal flow path 24, and the discharge port 262 located at the downstream end of the internal flow path 24. In the device body 21, the metal particle dispersion liquid 91 is supplied via the supply port 261. The metal particle dispersion liquid 91 irradiated with the laser light that has passed through the light-transmitting section 25 is discharged from the device body 21 via the discharge port 262. The internal flow path 24 includes a light-receiving section 240 that is irradiated with the laser light that has passed through the light-transmitting section 25. The application of ultrasonic waves to the metal particle dispersion liquid 91 by the ultrasonic wave application section 22 is preferably performed between the supply port 261 and the light-receiving section 240 of the internal flow path 24.

[0043] This allows metal particle dispersion liquid 91, immediately after the dispersibility of the metal microparticles has been improved by the application of ultrasonic waves, to be supplied to light receiving unit 240. Therefore, the uniformity of the laser light irradiation of the metal microparticles can be suitably improved in light receiving unit 240. As a result, the uniformity of the particle size of the metal microparticles after micronization can be further improved.

[0044] As described above, the internal flow path 24 includes the light receiving section 240 that is irradiated with the laser light that has passed through the light transmitting section 25. The light receiving section 240 extends in the vertical direction, and the flow of the metal particle dispersion liquid 91 in the light receiving section 240 is preferably from the bottom to the top. This allows the metal particle dispersion liquid 91 to fill the flow path without gaps in the light receiving section 240 (i.e., the metal particle dispersion liquid 91 is filled in the light receiving section 240) even when the flow rate of the metal particle dispersion liquid 91 is relatively small. As a result, the laser light can be efficiently and suitably irradiated to the metal particle dispersion liquid 91. As a result, the metal particles can be efficiently and suitably pulverized.

[0045] As described above, the internal flow path 24 includes the light receiving section 240 to which the laser light transmitted through the light transmitting section 25 is irradiated. The direction of incidence of the laser light on the light receiving section 240 is parallel to the thickness direction of the device body 21. Preferably, the thickness of the device body 21 is smaller than the size of the device body 21 in the vertical and horizontal directions perpendicular to the thickness direction. This allows the length of the light receiving section 240 that receives the laser light to be increased while favorably realizing the transmission of the laser light through the light receiving section 240. As a result, the laser light can be efficiently irradiated onto the metal particle dispersion liquid 91, and therefore the metal microparticles can be efficiently refined.

[0046] As described above, the LFL apparatus 1 includes the LFL device 2, the dispersion liquid supply unit 3, the light source unit 7, and the dispersion liquid recovery unit 4. The dispersion liquid supply unit 3 supplies a metal particle dispersion liquid 91 to the internal flow path 24 of the LFL device 2. The light source unit 7 emits laser light toward the light-transmitting unit 25 of the LFL device 2. The dispersion liquid recovery unit 4 recovers the metal particle dispersion liquid 91 discharged from the internal flow path 24 of the LFL device 2. This makes it possible to obtain fine metal microparticles with a high degree of particle size uniformity.

[0047] Next, an LFL device 2a according to a second embodiment of the present invention will be described with reference to Fig. 3 and Fig. 4. The LFL device 2a is provided in the LFL apparatus 1 shown in Fig. 1 and Fig. 2 in place of the above-mentioned LFL device 2, for example, and is used for micronizing metal particles in a metal particle dispersion liquid 91 by LFL. Fig. 3 is an enlarged view of a vertical cross section of the LFL device 2a at the center in the X direction. Fig. 4 is a view showing the configuration of a computer 5 that realizes a control unit 501 (described later) of the LFL device 2a.

[0048] 1 and 2, LFL device 2a further includes a flow path thickness changing unit 27, a light transmittance measuring unit 28, and a control unit 501. The other components of LFL device 2a are substantially the same as those of LFL device 2. In the following description, the components of LFL device 2a that correspond to those of LFL device 2 are given the same reference numerals as those of LFL device 2.

[0049] In the LFL device 2a, the (+Y) side light-transmitting member 232 of the two light-transmitting members 232 is attached to the frame 231 together with the (+Y) side connecting member 233 so as to be movable in the Y direction (i.e., thickness direction) with respect to the frame 231. Specifically, the (+Y) side connecting member 233 fixed to the (+Y) side light-transmitting member 232 is indirectly connected to the frame 231 via the flow path thickness changing unit 27. In the example shown in FIG. 3, an elastically deformable sealing member 271 (for example, an O-ring or the like) is provided between the connecting member 233 and the frame 231.

[0050] In the LFL device 2a, the (+Y)-side connection member 233 is moved in the Y direction by the flow path thickness changer 27, whereby the (+Y)-side light-transmitting member 232 is also moved in the Y direction, and the distance in the Y direction between the two light-transmitting members 232 is changed. As a result, the thickness in the thickness direction of the light-transmitting flow path 241 is changed, and the thickness in the thickness direction of the light-receiving unit 240, which is a part of the light-transmitting flow path 241, is also changed. The flow path thickness changer 27 is, for example, a plurality of air cylinders or linear motors. Note that the structure, type, and the like of the flow path thickness changer 27 may be changed in various ways. In the LFL device 2a, instead of the (+Y)-side light-transmitting member 232 or in addition to the (+Y)-side light-transmitting member 232, the (-Y)-side light-transmitting member 232 may be movable by the flow path thickness changer 27.

[0051] The light transmittance measuring unit 28 is an optical measuring unit that measures the light transmittance of the metal particle dispersion liquid 91 (see FIG. 1) in the light receiving unit 240 of the internal flow path 24. The light transmittance measuring unit 28 includes a light projecting unit 281 and a light receiving unit 282. The light projecting unit 281 is attached to a position overlapping the light receiving unit 240 in the Y direction on the (-Y) side main surface of the light transmitting member 232 on the (-Y) side in FIG. 3. The light projecting unit 281 includes, for example, a light source that emits light in the (+Y) direction. The wavelength of the light emitted from the light projecting unit 281 is changeable, and in the example shown in FIG. 3, the wavelength is set to be approximately the same as that of the laser light emitted from the light source unit 7.

[0052] 3, the light receiving unit 282 is attached at a position overlapping with the light receiving section 240 in the Y direction on the (+Y) side principal surface of the light transmitting member 232 on the (+Y) side in Fig. 3. The light receiving unit 282 includes a light receiving sensor that receives light emitted from the light projecting unit 281 and transmitted through the light receiving section 240. In the light receiving unit 282, the transmittance of light between the light projecting unit 281 and the light receiving unit 282 (i.e., the light transmittance) is found from the output of the light receiving sensor.

[0053] When the light transmittance of the two light-transmitting members 232 is relatively high, the light transmittance determined by the light-receiving unit 282 is regarded as the light transmittance of the metal particle dispersion liquid 91 flowing through the light-receiving section 240. On the other hand, when the light transmittance of the two light-transmitting members 232 is relatively low, the light transmittance of the metal particle dispersion liquid 91 flowing through the light-receiving section 240 is determined based on the light transmittance determined by the light-receiving unit 282 and taking into consideration the light transmittance of each light-transmitting member 232. The light transmittance of the metal particle dispersion liquid 91 in the light-receiving section 240 acquired by the light transmittance measuring section 28 is output to the computer 5 shown in FIG.

[0054] The computer 5 has a typical computer system configuration including a CPU 51, a ROM 52, a RAM 53, a fixed disk 54, a display 55, an input unit 56, a reading device 57, a communication unit 58, and a bus 50. The CPU 51 performs various arithmetic processing. The ROM 52 stores basic programs. The RAM 53 stores various information. The fixed disk 54 stores information. The display 55 is a display unit that displays various information such as images.

[0055] The input unit 56 includes a keyboard 56a and a mouse 56b for receiving input from an operator. The reader 57 reads information from a computer-readable recording medium 571 such as an optical disk, a magnetic disk, a magneto-optical disk, or a memory card. The display 55, the keyboard 56a, the mouse 56b, and the reader 57 are connected to the bus 50 via an interface I / F. The communication unit 58 transmits and receives signals to and from devices external to the computer 5. The bus 50 is a signal circuit that connects the CPU 51, the ROM 52, the RAM 53, the fixed disk 54, the display 55, the input unit 56, the reader 57, and the communication unit 58.

[0056] In computer 5, program 572 is read in advance from recording medium 571 via reader 57 and stored in fixed disk 54. Program 572 may be stored in fixed disk 54 via a network. CPU 51 executes arithmetic processing while using RAM 53 and fixed disk 54 in accordance with program 572. CPU 51 functions as a calculation unit in computer 5. Other configurations functioning as a calculation unit other than CPU 51 may be employed.

[0057] 3 is realized by the CPU 51, ROM 52, RAM 53, fixed disk 54 and their peripheral components. The control unit 501 drives the flow path thickness changing unit 27 based on the output from the light transmittance measuring unit 28 (i.e., the light transmittance of the metal particle dispersion liquid 91 in the light receiving unit 240) and adjusts the thickness of the light receiving unit 240 in the Y direction (i.e., the thickness direction) so that the metal fine particles in the metal particle dispersion liquid 91 flowing through the light receiving unit 240 are irradiated with laser light of sufficient intensity.

[0058] Specifically, when the light transmittance of the metal particle dispersion 91 in the light receiving unit 240 is relatively low (for example, when the concentration of metal microparticles in the metal particle dispersion 91 is relatively high), the light transmitting member 232 on the (+Y) side is moved in the (-Y) direction by the flow path thickness changing unit 27, and the thickness of the light receiving unit 240 in the Y direction is reduced. As a result, even metal microparticles located in a position away from the light source unit 7 in the light receiving unit 240 (i.e., the region on the (+Y) side of the light receiving unit 240) are irradiated with laser light of sufficient intensity, so that the metal microparticles are suitably micronized.

[0059] On the other hand, when the light transmittance of the metal particle dispersion liquid 91 in the light receiving unit 240 is relatively high (for example, when the concentration of metal fine particles in the metal particle dispersion liquid 91 is relatively low), the light transmitting member 232 on the (+Y) side is moved in the (+Y) direction by the flow path thickness changing unit 27, and the thickness of the light receiving unit 240 in the Y direction is increased. This makes it possible to increase the flow rate of the metal particle dispersion liquid 91 flowing through the light receiving unit 240 while irradiating the metal fine particles located at a position away from the light source unit 7 in the light receiving unit 240 with a laser beam of sufficient intensity. As a result, it is possible to increase the amount of the metal particle dispersion liquid 91 on which the liquid-phase laser fragmentation is performed per unit time. Note that the level of the light transmittance of the metal particle dispersion liquid 91 in the light receiving unit 240 varies depending on the type of the metal fine particles and the solvent as well as the concentration of the metal fine particles in the metal particle dispersion liquid 91.

[0060] As described above, in the LFL device 2a, the internal flow path 24 includes the light receiving section 240 that is irradiated with the laser light that has passed through the light transmitting section 25. The direction of incidence of the laser light on the light receiving section 240 is parallel to the thickness direction of the device body 21. The LFL device 2a further includes a flow path thickness changing section 27 that changes the thickness of the light receiving section 240 in the thickness direction. This makes it possible to perform liquid-phase laser fragmentation of the metal microparticles at the light receiving section 240 of an appropriate thickness (i.e., a thickness that allows the laser light to be suitably transmitted and is not excessively thin) in accordance with the concentration of the metal particle dispersion liquid 91, the type of metal microparticles, and the like.

[0061] As described above, it is preferable that the LFL device 2a further includes a light transmittance measuring unit 28 that measures the light transmittance of the metal particle dispersion liquid 91 in the light receiving unit 240, and a control unit 501 that drives the flow path thickness changing unit 27 based on the output from the light transmittance measuring unit 28. This makes it possible to automatically adjust the thickness of the light receiving unit 240 to an appropriate thickness in accordance with the light transmittance of the metal particle dispersion liquid 91.

[0062] Various modifications are possible to the LFL devices 2, 2a and LFL apparatus 1 described above.

[0063] For example, in the LFL device 2, the flow of the metal particle dispersion liquid 91 in the light receiving section 240 does not necessarily need to be from the bottom to the top, and the direction of the flow may be changed in various ways. For example, the light receiving section 240 may be bent or curved in the horizontal direction or the like, or may be serpentine. The same is true for the LFL device 2a.

[0064] In the LFL device 2, the application of ultrasonic waves to the metal particle dispersion liquid 91 by the ultrasonic wave application unit 22 does not necessarily have to be performed between the light receiving unit 240 and the supply port 261, and may be performed at another position. For example, the application of ultrasonic waves may be performed at the upstream end of the light receiving unit 240 (the lower end of the light receiving unit 240 in the example shown in FIG. 1). Alternatively, the application of ultrasonic waves may be performed to the metal particle dispersion liquid 91 flowing through the internal flow channel 24 at various positions (e.g., the supply port 261, etc.) upstream of the light receiving unit 240. The same applies to the LFL device 2a.

[0065] In the LFL device 2a, the light projecting unit 281 and the light receiving unit 282 of the light transmittance measuring unit 28 do not necessarily need to be arranged to face each other across the light receiving unit 240, and may be arranged to face each other across the supply pipe 32 when the supply pipe 32 is a transparent pipe, for example. In this case, the light transmittance in the light receiving unit 240 is found based on the output from the light receiving sensor of the light receiving unit 282, the light transmittance of the supply pipe 32, and the relationship between the diameter of the supply pipe 32 and the thickness of the light receiving unit 240, etc. Note that when the light projecting unit 281 and the light receiving unit 282 are arranged to face each other across the supply pipe 32, the light projecting unit 281 and the light receiving unit 282 are preferably arranged between the liquid delivery unit 33 and the supply port 261.

[0066] The structure and type of the light transmittance measuring unit 28 are not limited to those described above and may be modified in various ways. For example, in the LFL device 2a, a calculation unit that calculates the light transmittance of the metal particle dispersion liquid 91 from the output of the light receiving sensor of the light receiving unit 282 may be realized by the computer 5.

[0067] In the LFL device 2a, the flow path thickness changing section 27 does not necessarily have to be driven by the control section 501, and the thickness of the light receiving section 240 may be changed by an operator operating the LFL apparatus 1 manually operating the flow path thickness changing section 27.

[0068] The LFL devices 2 and 2a may be provided in an LFL apparatus having a configuration different from that of the above-described LFL apparatus 1, and used for liquid-phase laser fragmentation of metal microparticles.

[0069] The configurations in the above-described embodiment and each of the modified examples may be combined as appropriate as long as they are not mutually inconsistent. [Explanation of symbols]

[0070] 1 LFL device (liquid phase laser fragmentation device) 2,2a LFL device (liquid phase laser fragmentation device) 3 Dispersion liquid supply section 4. Dispersion liquid recovery section 7 Light source section 21 Device body 22 Ultrasonic wave application unit 24 Internal flow path 25 Translucent part 27 Flow passage thickness change section 28 Light transmittance measurement section 91 Metal particle dispersion 240 Light receiving part 261 Supply Port 262 Exhaust port 501 Control section

Claims

1. 1. A device for liquid phase laser fragmentation, comprising: The device body, an ultrasonic wave applying unit attached to the device body; Equipped with An internal flow path is provided inside the device body through which a metal particle dispersion liquid in which metal fine particles are dispersed flows, the ultrasonic wave applying unit applies ultrasonic waves to the metal particle dispersion liquid flowing through the internal flow path, A device for liquid phase laser fragmentation, wherein an outer surface of the device body is provided with a light-transmitting portion through which laser light passes which is irradiated onto the metal particle dispersion liquid in the internal flow path to which ultrasound is applied by the ultrasound application portion.

2. 2. The device for liquid phase laser fragmentation according to claim 1, The device body includes: a supply port located at an end portion on an upstream side of the internal flow path, to which the metal particle dispersion liquid is supplied; an exhaust port located at an end portion on a downstream side of the internal flow path, through which the metal particle dispersion liquid irradiated with the laser light that has passed through the light-transmitting portion is exhausted; Equipped with the internal flow path includes a light receiving portion that is irradiated with the laser light that has passed through the light transmitting portion, The device for liquid phase laser fragmentation, wherein ultrasonic waves are applied to the metal particle dispersion by the ultrasonic application unit between the supply port and the light receiving unit of the internal flow path.

3. 2. The device for liquid phase laser fragmentation according to claim 1, the internal flow path includes a light receiving portion that is irradiated with the laser light that has passed through the light transmitting portion, The light receiving portion extends in a vertical direction, A device for liquid phase laser fragmentation, wherein the flow of the metal particle dispersion liquid in the light receiving portion is from the bottom to the top.

4. 2. The device for liquid phase laser fragmentation according to claim 1, the internal flow path includes a light receiving portion that is irradiated with the laser light that has passed through the light transmitting portion, the direction of incidence of the laser light on the light receiving unit is parallel to the thickness direction of the device body, A device for liquid phase laser fragmentation, wherein the thickness of the device body is smaller than the size of the device body in the vertical and horizontal directions perpendicular to the thickness direction.

5. 2. The device for liquid phase laser fragmentation according to claim 1, the internal flow path includes a light receiving portion that is irradiated with the laser light that has passed through the light transmitting portion, the direction of incidence of the laser light on the light receiving unit is parallel to the thickness direction of the device body, The liquid-phase laser fragmentation device further includes a flow path thickness changing section that changes a thickness of the light receiving section in the thickness direction.

6. 6. A device for liquid phase laser fragmentation according to claim 5, a light transmittance measuring unit for measuring the light transmittance of the metal particle dispersion liquid in the light receiving unit; a control unit that drives the flow path thickness changing unit based on an output from the light transmittance measuring unit; The device for liquid phase laser fragmentation further comprises:

7. A liquid phase laser fragmentation apparatus comprising: A device for liquid-phase laser fragmentation according to any one of claims 1 to 6; a dispersion supply unit that supplies the metal particle dispersion to the internal flow path of the device for liquid-phase laser fragmentation; a light source unit that emits laser light toward the light transmitting unit of the liquid phase laser fragmentation device; a dispersion recovery unit that recovers the metal particle dispersion discharged from the internal flow path of the device for liquid-phase laser fragmentation; A liquid phase laser fragmentation apparatus comprising:

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