Fluid device

Abstract

To provide a fluid device that can stably generate standing waves in a channel.SOLUTION: A fluid device captures fine particles in fluid by using ultrasonic waves, and the fluid device comprises: a channel that extends along a first axis, in which the fluid including the fine particles flows along the first axis; a first ultrasonic element that is arranged in the channel, and generates standing waves along a second axis intersecting the first axis in the channel; a movable wall that is provided on at least one of a pair of channel walls facing each other along the second axis in the channel; and a movable part that moves the movable wall along the second axis.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a fluidic device. [Background technology]

[0002] Conventionally, fluidic devices that acoustically focus particles in a fluid are known. For example, a fluidic device disclosed in Non-Patent Document 1 transmits ultrasonic waves from an ultrasonic element into a flow channel to form a standing wave. As a result, particles contained in the fluid flowing through the flow channel are trapped at the node positions of the standing wave due to the pressure gradient of the standing wave. The trapped particles are diverted to one outlet (concentrated fluid outlet) of the flow channel, and the diluted fluid is diverted to the other outlet (diluted fluid outlet). [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] E. Benes, and 10 others, “ULTRASONIC SEPARATION OF SUSPENDED PARTICLES”, Reprint Proc. of the 2001 IEEE International Ultrasonics Symposium, a Joint Meeting with the World Congress on Ultrasonics, Atlanta, Georgia, USA, Oct. 7-10, 2001, p649-659. Summary of the Invention [Problem to be solved by the invention]

[0004] When a standing wave is formed, the relationship L = nc / 2f holds, where L is the flow path width, c is the speed of sound, n is the order, and f is the frequency of the ultrasound. However, when ultrasonic elements are mass-produced, the ultrasonic frequency of each ultrasonic element varies slightly due to manufacturing errors. The same is true for fluidic devices, where the flow path width L also varies slightly depending on the individual fluidic device due to manufacturing errors. Furthermore, the speed of sound changes slightly depending on the temperature of the fluid, and the flow path width may also change depending on the thermal expansion coefficient of the fluidic device. For this reason, it is difficult to maintain the flow path width of a fluidic device and the frequency of the ultrasound so that they satisfy the relationship L = nc / 2f. If the above condition cannot be met, it becomes difficult to stably generate standing waves in the flow path. [Means for solving the problem]

[0005] A fluidic device according to a first aspect of the present disclosure is a fluidic device that uses ultrasound to capture microparticles in a fluid, and includes: a flow path extending along a first axis through which a fluid containing the microparticles flows along the first axis; a first ultrasonic element disposed in the flow path and generating a standing wave within the flow path along a second axis that intersects the first axis; a movable wall provided on at least one of a pair of flow path walls that face each other along the second axis in the flow path; and a movable part that moves the movable wall along the second axis. [Brief explanation of the drawings]

[0006] [Figure 1] FIG. 1 is a perspective view schematically showing a fluidic device according to a first embodiment. [Figure 2] 2 is a cross-sectional view of the fluidic device taken along plane A parallel to the XY plane of FIG. 1. FIG. [Figure 3] 2 is a cross-sectional view of the fluidic device taken along plane B parallel to the YZ plane in FIG. 1. [Figure 4] FIG. 2 is a block diagram showing the configuration of a controller and the control configuration of a processor in the fluidic device of the first embodiment. [Figure 5] 4 is a flowchart showing a control method for the fluidic device of the first embodiment. [Figure 6]6 is a flowchart showing details of the sound field adjustment process in FIG. 5; [Figure 7] FIG. 10 is a schematic cross-sectional view of a separation section of a fluidic device according to a second embodiment, taken along the YZ plane. [Figure 8] FIG. 11 is a schematic cross-sectional view of a separation section of a fluidic device according to a third embodiment, taken along the YZ plane. [Figure 9] FIG. 10 is a block diagram showing the configuration of a controller and the control configuration of a processor in a fluidic device according to a third embodiment. [Figure 10] 10 is a flowchart showing details of a sound field adjustment process according to a third embodiment. [Figure 11] 11 is a flowchart showing details of the sound field adjustment process of FIG. 10 . [Figure 12] FIG. 10 is a cross-sectional view showing a cross section of a part of a fluidic device according to a second modification. DETAILED DESCRIPTION OF THE INVENTION

[0007] [First embodiment] Hereinafter, a fluidic device according to a first embodiment of the present disclosure will be described. (Configuration of fluidic device) Fig. 1 is a perspective view schematically illustrating a fluidic device 10 according to the present embodiment. Fig. 2 is a cross-sectional view of the fluidic device 10 taken along a plane A parallel to the XY plane in Fig. 1, and Fig. 3 is a cross-sectional view of the fluidic device 10 taken along a plane B parallel to the ZY plane in Fig. 1. The fluidic device 10 of this embodiment includes an inflow channel 20, a separation section 30, a first outflow channel 40, a second outflow channel 50, a first ultrasonic element 60 (see FIG. 2), a second ultrasonic element 70 (see FIG. 2), and a controller 80. The inflow channel 20, the separation section 30, the first outflow channel 40, and the second outflow channel 50 form a channel of the present disclosure. In the fluidic device 10 of this embodiment, a fluid containing fine particles flows from the inflow channel 20 into the separation section 30. Here, the inflow direction of the fluid from the inflow channel 20 into the separation section 30 is defined as the X direction, and the fluid flows toward the +X side along a first axis L1 (see FIG. 2) that is parallel to the X direction. 1, the direction intersecting (e.g., perpendicular to) the X direction is the Y direction, and the direction intersecting (e.g., perpendicular to) the X and Y directions is the Z direction. In this embodiment, the first ultrasonic element 60 transmits ultrasonic waves along a second axis L2 (see FIGS. 2 and 3) parallel to the Y direction, thereby forming a standing wave (first standing wave SW1) along the second axis L2. The second ultrasonic element 70 transmits ultrasonic waves along a third axis L3 (see FIG. 2) parallel to the Z direction, thereby forming a standing wave (second standing wave SW2) along the third axis L3.

[0008] (Configuration of inflow channel 20) Inflow channel 20 extends along first axis L1, and is connected to the −X side, +Y side, and center in the Z direction of separation section 30. The cross-sectional shape of inflow channel 20 is not particularly limited, and may be formed to have a rectangular cross section as shown in FIG. 1, or may be formed to have a circular cross section.

[0009] (Configuration of Separation Unit 30 and Ultrasonic Elements 60, 70) The separation section 30 separates fine particles from the fluid flowing in from the inlet flow path 20, and flows a concentrated fluid containing a large amount of the separated fluid into the first outlet flow path 40, and flows a diluted fluid from which the fine particles have been separated into the second outlet flow path 50. Specifically, as described above, the inflow channel 20 is connected to the separation unit 30 on the −X side, the +Y side, and the center in the Z direction. Furthermore, the first outflow channel 40 is connected to the separation unit 30 on the +X side, the +Y side, and the center in the Z direction, i.e., at a position facing the inflow channel 20. Furthermore, the second outflow channel 50 is connected to the separation unit 30 on the +X side and the −Y side.

[0010] The separator 30 has a pair of opposing surfaces that face each other in the Y direction and a pair of opposing surfaces that face each other in the Z direction. 2 and 3, one of a pair of opposing surfaces facing each other in the Y direction is a first movable wall 311 that can move back and forth in the Y direction, and the other is a first fixed wall 312 that does not move in either direction. For example, in this embodiment, the first movable wall 311 is disposed on the -Y side, and the first fixed wall 312 is disposed on the +Y side. More specifically, a first recess 313 that is recessed in a direction away from the flow path, i.e., toward the -Y side, is provided on the -Y side surface of the separation unit 30. When viewed from the Y direction, the outer circumferential shape of the first recess 313 and the first movable wall 311 have substantially the same shape, and the first movable wall 311 can advance and retreat within the recess of the first recess 313. For example, in this embodiment, the first movable wall 311 and the first recess 313 are formed in a rectangular shape when viewed from the Y direction. Furthermore, when viewed from the Y direction, the first recess 313 and the first movable wall 311 may be formed to be the same size, but if the first movable wall 311 slides against the side surface of the first recess 313 as it moves in the Y direction, a force is required to resist the friction during sliding. For this reason, it is preferable to provide a gap of a predetermined dimension between the first movable wall 311 and the first recess 313.

[0011] A first movable part 314 is provided inside the first recess 313. This first movable part 314 connects the bottom surface 313A of the first recess 313 and the first movable wall 311, and moves the first movable wall 311 back and forth in the Y direction. For example, a piezoelectric actuator or the like can be used as the first movable part 314. In this embodiment, since fluid may enter the first recess 313 through a gap between the first movable wall 311 and the first recess 313, the first movable part 314 has a waterproof function. For example, the wiring part of the piezoelectric actuator is sealed with a waterproof member. 2 and 3 show an example in which a single first movable part 314 is arranged in the first recess 313, but there is no particular limitation on the number of first movable parts 314. For example, a plurality of first movable parts 314 may be arranged at equal intervals in the first recess 313.

[0012] 3, in this embodiment, the pair of surfaces facing each other in the Z direction are the second fixed wall 322A and the third fixed wall 322B, neither of which moves in either direction, and therefore the second fixed wall 322A and the third fixed wall 322B are fixed at a predetermined distance from each other.

[0013] With respect to such a separation unit 30, the first ultrasonic element 60 forms a first standing wave SW1 between the first movable wall 311 and the first fixed wall 312 along a second axis L2 parallel to the Y direction. The second ultrasonic element 70 also forms a second standing wave SW2 along a third axis L3 parallel to the Z direction between the second fixed wall 322A and the third fixed wall 322B. The first standing wave SW1 and the second standing wave SW2 are each high-order standing waves having multiple nodes, and trap particles at the positions of the nodes or antinodes due to the pressure gradient of the ultrasonic waves. 3, for example, multiple horizontal dashed dotted lines indicate the positions of nodes in the first standing wave SW1, and multiple vertical dashed dotted lines indicate the positions of nodes in the second standing wave SW2. In this case, particles in the fluid are subjected to the acoustic radiation forces (ultrasonic wave pressure gradients) of the first standing wave SW1 and the second standing wave SW2 toward the positions of intersections of the horizontal dashed dotted lines and the vertical dashed dotted lines.

[0014] Thin-film ultrasonic elements can be used as the first ultrasonic element 60 and the second ultrasonic element 70. These thin-film ultrasonic elements are formed by arranging a plurality of ultrasonic transducers, each having a piezoelectric element disposed in a thin-film vibration portion, in an array, and transmitting ultrasonic waves by vibrating each vibration portion when a voltage is applied to each piezoelectric element. When using such thin-film ultrasonic elements, it is preferable to arrange them so that the ultrasonic transmission surfaces (the vibration portions) of the first ultrasonic element 60 and the second ultrasonic element 70 face the flow path of the separation unit 30. 2 and 3, the first ultrasonic element 60 is arranged on the +Y side of the second axis L2, with the -Y side of the first fixed wall 312 in contact with the fluid being the ultrasonic transmission surface of the first ultrasonic element 60. Note that the first ultrasonic element 60 may also be arranged so that the +Y side of the first movable wall 311 on the -Y side of the second axis L2 is the ultrasonic transmission surface of the first ultrasonic element 60. 3, the second ultrasonic element 70 is disposed on the second fixed wall 322A disposed on the −Z side of the third axis L3 such that the +Z side surface that contacts the fluid becomes the ultrasonic transmission surface of the second ultrasonic element 70. Alternatively, the second ultrasonic element 70 may be disposed on the second fixed wall 322A on the +Z side of the third axis L3 such that the −Z side surface that contacts the fluid becomes the ultrasonic transmission surface of the second ultrasonic element 70.

[0015] Note that bulk ultrasonic elements that transmit ultrasonic waves by applying a voltage to a piezoelectric body to vibrate the piezoelectric body itself may be used as the first ultrasonic element 60 and the second ultrasonic element 70. In this case, it is only necessary that ultrasonic waves can propagate to the separation unit 30, and the first ultrasonic element 60 and the second ultrasonic element 70 may be disposed at positions away from the flow path. For example, a configuration can be exemplified in which the first ultrasonic element 60 is fixed to the outer wall surface 312A of the first fixed wall 312 on the -Y side of the separation section 30, and the second ultrasonic element 70 is fixed to the outer wall surface 322C of the second fixed wall 322A on the -Z side of the separation section 30.

[0016] In this separation unit 30, particles in the fluid flowing in from the inflow channel 20 are trapped by a node of the first standing wave SW1 formed along the second axis L2 parallel to the Y direction and a node of the second standing wave SW2 formed along the third axis L3 parallel to the Z direction. For example, in the example of FIG. 3 , the fluid introduced from the inflow channel 20 is trapped at the intersection (trapping position S) of the node of the first standing wave SW1 and the node of the second standing wave SW2 indicated by a circle in FIG. 3 . The trapped particles then move toward the +X side along the X direction with the flow of the fluid and are discharged from the first outlet channel 40. As a result, a concentrated fluid with a high concentration of particles flows out from the first outlet channel 40. On the other hand, the fluid that flows from the inflow channel 20 into the separation section 30 spreads and flows to the -Y side and ±Z side of the separation section 30. However, because the particles are captured at the capture position S as described above, the concentration of particles in the fluid that spreads and flows to the -Y side and ±Z side of the separation section 30 is low, and a diluted fluid with a low concentration of particles flows out from the second outflow channel 50.

[0017] (Configuration of the first outflow channel 40 and the second outflow channel 50) As described above, the first outlet flow channel 40 is connected to the +X side, +Y side, and central position in the Z direction of the separation section 30, and is provided coaxially with the inlet flow channel 20 (first axis L1) and parallel to the X direction. As described above, the fine particles of the fluid that flows from the inlet flow path 20 into the separation section 30 are captured at capture position S, which is the node position on the +Y side of the first standing wave SW1 and the node position near the center in the Z direction of the second standing wave SW2, and therefore the concentrated fluid containing these captured fine particles can be discharged from the first outlet flow path 40 by riding on the fluid flowing along the first axis L1.

[0018] The second outlet flow path 50 is connected to the separation unit 30 at a position different from the first outlet flow path 40 on the +X side and the -Y side, and discharges the dilution fluid. For example, as shown in FIG. 1 , the second outlet flow path 50 may be connected to the separation unit 30 on the +X side and the -Y side, from the -Z side to the +Z side in the Z direction. Alternatively, the second outlet flow path 50 may be provided at a position on the +X side, the -Y side, and the -Z side, and at a position on the +X side, the -Y side, and the +Z side. Furthermore, because particulates are captured at the node position at the center of the second standing wave SW2 in the Z direction, the second outlet flow path 50 may be provided at a position on the +X side, the +Y side, and the +Z side of the separation unit 30, or at a position on the +X side, the +Y side, and the -Z side of the separation unit 30.

[0019] The above-described connection positions of the inlet flow channel 20, the first outlet flow channel 40, and the second outlet flow channel 50 to the separation section 30 are merely examples and are not limited to these. As long as the first outlet flow channel 40 is disposed at a position opposite the inlet flow channel 20, the connection positions of the inlet flow channel 20, the first outlet flow channel 40, and the second outlet flow channel 50 to the separation section 30 are not particularly limited. For example, the inlet flow path 20 may be connected to the -X side of the separation section 30 at a central position in the Z and Y directions, the first outlet flow path 40 may be connected to the +X side of the separation section 30 at a central position in the Z and Y directions, and the second outlet flow path 50 may be connected to the +X side of the separation section 30 so as to surround the first outlet flow path 40.

[0020] (Configuration of the controller 80) FIG. 4 is a block diagram showing a schematic configuration of the controller 80 and a functional configuration of the processor 842. The control controller 80 controls the operations of the first ultrasonic element 60, the second ultrasonic element 70, and the first movable part 314. The control controller 80 includes, for example, a first ultrasonic control circuit 81 that controls the driving of the first ultrasonic element 60, a second ultrasonic control circuit 82 that controls the driving of the second ultrasonic element 70, a first movable control circuit 83 that controls the driving of the first movable part 314, and a control unit 84.

[0021] The first ultrasonic control circuit 81 includes a first transmission circuit 811 for outputting ultrasonic waves of a predetermined first frequency from the first ultrasonic element 60. This first transmission circuit 811 generates a drive voltage signal of a predetermined drive frequency to be output to the first ultrasonic element 60. In this embodiment, the drive frequency of the drive voltage signal generated by the first transmission circuit 811 is fixed, and as a result, the first frequency of the ultrasonic waves output from the first ultrasonic element 60 becomes a preset fixed frequency.

[0022] The first ultrasonic control circuit 81 also includes a first detection circuit 812 for detecting whether the first standing wave SW1 is generated in the Y direction. The configuration for detecting the formation of the first standing wave SW1 is not particularly limited. For example, if the first ultrasonic element 60 is a thin-film ultrasonic element, the formation of the first standing wave SW1 causes the ultrasonic transmission / reception surface to become the antinode, and the impedance of the first ultrasonic element 60 therefore takes on a maximum value. Therefore, an example of the first detection circuit 812 is an impedance detection circuit that measures the impedance of the first ultrasonic element 60. In this embodiment, the first movable wall 311 is advanced and retreated in the Y direction by the first movable part 314, and the position at which the impedance maximum is detected by the first detection circuit 812 can be identified, thereby identifying the position of the first movable wall 311 when the first standing wave SW1 is formed. Furthermore, for example, when the first ultrasonic element 60 is a bulk type ultrasonic element, an ultrasonic receiving element may be provided on the +Y side surface of the first fixed wall 312 that contacts the fluid, or on the -Y side surface of the first movable wall 311, and when the intensity of the ultrasonic wave received by the ultrasonic receiving element reaches a peak value, the formation of the first standing wave SW1 may be detected.

[0023] The second ultrasonic control circuit 82 includes a second transmission circuit 821 for outputting ultrasonic waves of a predetermined second frequency from the second ultrasonic element 70. The second transmission circuit 821 generates a drive voltage signal to be output to the second ultrasonic element 70. Here, in the present embodiment, the second transmission circuit 821 is capable of changing the drive frequency of the drive voltage signal within a predetermined frequency band, thereby changing the second frequency of the ultrasonic waves output from the second ultrasonic element 70.

[0024] The second ultrasonic control circuit 82 also includes a second detection circuit 822 for detecting whether or not a second standing wave SW2 is generated in the Z direction. The second detection circuit 822 can be configured similarly to the first detection circuit 812. For example, when the second ultrasonic element 70 is a thin-film ultrasonic element and the ultrasonic transmission surface of the second ultrasonic element 70 is arranged on the surface of the second fixed wall 322A or the third fixed wall 322B facing the flow path, an impedance measurement circuit that measures the impedance of the second ultrasonic element 70 may be used. Furthermore, for example, when the second ultrasonic element 70 is a bulk-type ultrasonic element, an ultrasonic receiving element may be provided on the +Z side surface of the second fixed wall 322A that contacts the fluid, or on the -Z side surface of the third fixed wall 322B, and when the intensity of the ultrasonic waves received by the ultrasonic receiving element reaches a peak value, the formation of the second standing wave SW2 may be detected.

[0025] The first movable control circuit 83 controls the drive voltage (first movable control signal) for driving the first movable portion 314, and moves the first movable wall 311 forward and backward in the Y direction.

[0026] The control unit 84 can be configured, for example, by a general computer including a storage unit 841 and a processor 842 . The storage unit 841 stores various data and programs for controlling the fluidic device 10. The processor 842 functions as a first continuous wave generating unit 842A, a first movable adjustment unit 842B, a first standing wave condition determining unit 842C, a second continuous wave generating unit 842D, and a second standing wave condition determining unit 842E by appropriately reading and executing the programs stored in the memory unit 841.

[0027] The first continuous wave generating unit 842A outputs a first transmission command to the first transmitting circuit 811, causing the first transmitting circuit 811 to input a drive voltage of a predetermined drive frequency to the first ultrasonic element 60. As a result, ultrasonic waves of the first frequency are transmitted from the first ultrasonic element 60.

[0028] The first movable adjustment unit 842B outputs a first movable command including a drive command value for the first movable unit 314 to the first movable control circuit 83. As a result, a first movable control signal of a drive voltage according to the drive command value is output from the first movable control circuit 83 to the first movable unit 314, and the first movable unit 314 moves the first movable wall 311 along the Y direction by a drive amount according to the first movable command.

[0029] The first standing wave condition determination unit 842C determines whether the first standing wave SW1 is generated based on the detection value of the first detection circuit 812 when the first movable wall 311 is moved by the first movable adjustment unit 842B. Furthermore, the first standing wave condition determination unit 842C identifies the position of the first movable wall 311 at the timing when it is determined that the first standing wave SW1 is generated. For example, it identifies the position of the first movable wall 311 at which the change in impedance of the first ultrasonic element 60 becomes a local maximum value when the first movable wall 311 is moved in the Y direction.

[0030] The second continuous wave generating unit 842D outputs a second transmission command including a frequency command value to the second transmission circuit 821. As a result, a drive voltage having a drive frequency corresponding to the frequency command value is input from the second transmission circuit 821 to the second ultrasonic element 70, and ultrasonic waves having a second frequency corresponding to the frequency command value are transmitted from the second ultrasonic element 70. By sequentially changing the frequency command value of the second transmission command output from the second continuous wave generating unit 842D, the frequency of the ultrasonic waves transmitted from the second ultrasonic element 70 can be swept.

[0031] The second standing wave condition determination unit 842E determines whether or not a second standing wave SW2 has been generated based on the detection value of the second detection circuit 822 when the second continuous wave generation unit 842D sweeps the second frequency from the second ultrasonic element 70. Furthermore, the second standing wave condition determination unit 842E identifies the second frequency at the timing when the second standing wave SW2 is generated.

[0032] [Method for controlling fluid device 10] Next, a method for controlling the above-described fluidic device 10 will be described. FIG. 5 is a flowchart showing a method for controlling the fluidic device 10 of this embodiment. In this embodiment, when the fluidic device 10 is started and fluid is introduced, first, a sound field adjustment process (step S1) is performed.

[0033] FIG. 6 is a detailed flowchart of the sound field adjustment process in step S1. In the sound field adjustment process, first, the second continuous wave generating unit 842D outputs a second transmission command including a frequency command value to the second transmission circuit 821, and changes the frequency command value to sweep the second frequency of the ultrasonic waves transmitted from the second ultrasonic element 70 (step S11). Then, the second standing wave condition determination unit 842E identifies the second frequency at the timing when the second standing wave SW2 is formed based on the detection value of the second detection circuit 822 when the second frequency is swept in step S11 (step S12). For example, if the second ultrasonic element 70 is a thin-film ultrasonic element and the surface of the second fixed wall 322A or the third fixed wall 322B that contacts the fluid is the ultrasonic transmission surface of the second ultrasonic element 70, the second frequency at which the change in impedance of the second ultrasonic element 70 when the second frequency is changed is maximized is identified.

[0034] Next, the first continuous wave generating unit 842A outputs a first transmission command to the first transmission circuit 811. As a result, ultrasonic waves of a predetermined first frequency set in advance are transmitted from the first ultrasonic element 60 (step S13). In addition, the first movable adjustment unit 842B outputs a first movable command including a drive command value to the first movable control circuit 83, and changes the drive amount to move the first movable wall 311 forward and backward in the Y direction (step S14). Then, the first standing wave condition determination unit 842C identifies the position of the first movable wall 311 at the timing when the first standing wave SW1 is formed based on the detection value of the first detection circuit 812 when the first movable wall 311 is moved in step S14 (step S15). For example, if the first ultrasonic element 60 is a thin-film type ultrasonic element and the -Y side surface of the first fixed wall 312 or the +Y side surface of the first movable wall 311 is the ultrasonic transmission surface of the first ultrasonic element 60, the position of the first movable wall 311 where the change in impedance of the first ultrasonic element 60 when the first movable wall 311 is moved becomes a local maximum value is identified.

[0035] After the sound field adjustment process of step S1, the first movable adjustment unit 842B moves the first movable wall 311 to the position identified in step S15 (step S2). Furthermore, the first continuous wave generation unit 842A and the second continuous wave generation unit 842D perform a continuous wave (ultrasound wave) transmission process (step S3). That is, the first continuous wave generation unit 842A causes the first ultrasonic element 60 to transmit ultrasound waves of a preset first frequency, and the second continuous wave generation unit 842D transmits ultrasound waves of the second frequency identified in step S12.

[0036] As a result, the flow path width in the Y direction of the separation unit 30 is adjusted to a flow path width that can form a first standing wave SW1 for the first frequency of the ultrasonic waves transmitted from the first ultrasonic element 60, and the first standing wave SW1 is formed along the second axis L2. Furthermore, the second frequency of the ultrasonic waves transmitted from the second ultrasonic element 70 is adjusted to a frequency that can form a second standing wave SW2 for the flow path width in the Z direction of the separation unit 30, and the second standing wave SW2 is formed along the third axis L3.

[0037] Thereafter, in this embodiment, the controller 80 further determines whether a predetermined measurement timing has arrived (step S4). The measurement timing may be, for example, a predetermined cycle that has been set in advance, or may be a timing arbitrarily designated by the user. Alternatively, it may be a timing when a temperature change of the fluid or a temperature change of the fluidic device 10 is detected. If the determination in step S4 is YES, the process returns to step S1, and the sound field adjustment process is performed. As a result, in this embodiment, the flow path width in the Y direction of the separation unit 30 and the second frequency of the ultrasonic waves transmitted from the second ultrasonic element 70 are periodically adjusted so as to satisfy the conditions for forming the first standing wave SW1 and the second standing wave SW2.

[0038] If the determination in step S4 is NO, the controller 80 determines whether or not a stop command has been issued (step S5). The stop command may be input by a user's input operation, or may be output from a fluid introduction mechanism (not shown) that introduces fluid into the fluidic device 10 when the fluid to be introduced runs out. If the determination in step S5 is YES, the operation of the fluidic device 10 is terminated, and the ultrasonic wave transmission operations of the first ultrasonic element 60 and the second ultrasonic element 70 are stopped. If the determination in step S5 is NO, the process returns to step S3.

[0039] In this embodiment, the sound field adjustment process allows a simple configuration to accurately form the first standing wave SW1 along the second axis L2 and the second standing wave SW2 along the third axis L3. That is, it is difficult to make the width of the flow channel of the fluidic device 10 the same as the width of the flow channel at the time of design due to manufacturing errors, etc. In order to form a standing wave in the flow channel, it is necessary to satisfy the following formula (1), where f is the frequency of the ultrasound, n is the order, and c is the speed of sound in the fluid.

[0040]

number

[0041] If the design value of the flow path width is L0 and the increase or decrease in the flow path width due to a manufacturing error is ΔL, the frequency condition f for forming a standing wave when there is a manufacturing error is given by the following equation (2).

[0042]

number

[0043] Therefore, the difference f-f0 between the frequency condition f0 for forming a standing wave when there is no manufacturing error and the frequency condition f for forming a standing wave when there is a manufacturing error is given by the following formula (3).

[0044]

number

[0045] For example, when L0 = 3 mm, ΔL = 50 μm, and c = 1480 m / s, f0 = 1941 kHz and f = 1973 kHz, resulting in a frequency difference of f - f0 = 32 kHz. Since the acoustic radiation force (stress due to the pressure gradient caused by ultrasound) generated by the standing wave is significantly reduced even by a deviation of a few kHz, it is necessary to set an appropriate frequency taking into account manufacturing errors in the flow channel, changes in the speed of sound due to temperature changes in the fluid, and expansion and contraction of the flow channel width due to temperature changes in the fluidic device. On the other hand, when multiple standing waves are formed using multiple ultrasonic elements (first ultrasonic element 60, second ultrasonic element 70) and the frequency of each ultrasonic element is controlled individually, the cost of the circuit configuration of the control circuit corresponding to each ultrasonic element (first continuous wave generating unit 842A and second continuous wave generating unit 842D) becomes high. In contrast, in this embodiment, the frequency of the second ultrasonic element 70 is only corrected to match the channel width in the Z direction of the separation unit 30, so the circuit configuration can be simplified compared to when the frequencies of both the first ultrasonic element 60 and the second ultrasonic element 70 are corrected. The first standing wave SW1 formed by the ultrasonic waves transmitted from the first ultrasonic element 60 is formed by moving the first movable wall 311 in the Y direction. Therefore, even if a manufacturing error occurs in the fluidic device 10, the first movable wall 311 can be moved to cancel the error. This makes it possible to satisfy the standing wave formation condition of equation (1) with a simple circuit configuration.

[0046] [Effects of this embodiment] The fluidic device 10 of this embodiment extends along a first axis L1 and includes a flow path (an inlet flow path 20, a separation section 30, and a first outlet flow path 40) through which a fluid containing fine particles flows along the first axis L1, and a first ultrasonic element 60 disposed in the flow path and generating a first standing wave SW1 along a second axis L2 within the flow path. The separation section 30 includes a first movable wall 311 and a first fixed wall 312 facing each other in the Y direction, and further includes a first movable section 314 that moves the first movable wall 311 along the Y direction. In this configuration, the channel width between the first movable wall 311 and the first fixed wall 312 can be changed to match the conditions of the first standing wave SW1 in response to the frequency of the ultrasonic waves output from the first ultrasonic element 60. This allows the channel width to be adjusted to a value that allows the first standing wave SW1 to be formed in response to the ultrasonic waves output from the first ultrasonic element 60, even if there is a manufacturing error in the channel width of the fluidic device 10, or if there is a manufacturing error in the first frequency of the ultrasonic waves transmitted from the first ultrasonic element 60, or if there is a channel width due to a change in the speed of sound caused by a temperature change in the fluid or thermal expansion of the fluidic device 10. Furthermore, changing the first frequency complicates the circuit configuration that controls the first ultrasonic element 60 and increases costs. In contrast, in this embodiment, the first transmission circuit 811 of the first ultrasonic control circuit 81 only needs to control the transmission of ultrasonic waves at a predetermined fixed first frequency, which simplifies the circuit configuration and contributes to reducing the cost of the device.

[0047] In this embodiment, the first ultrasonic element 60 is disposed at a position facing the first movable wall 311 across the flow path of the separation unit 30. For example, if the first ultrasonic element 60 is a thin-film ultrasonic element, the ultrasonic waves output from the ultrasonic transmission surface of the first ultrasonic element 60 can be propagated directly into the fluid, making it possible to capture microparticles with a high acoustic radiation force. In particular, in this embodiment, the separation unit 30 is provided with a first recess 313, and the first movable wall 311 is provided for the first recess 313. Therefore, both ±Y sides of the first movable wall 311 are exposed to the fluid, making it difficult to maintain waterproofing of the wiring of the first ultrasonic element 60. In contrast, in a configuration in which the first ultrasonic element 60 is provided on the first fixed wall 312 side, sealing between the first ultrasonic element 60 and the first fixed wall 312 makes it easy to maintain waterproofing of the wiring.

[0048] In this embodiment, when a bulk-type ultrasonic element is used as the first ultrasonic element 60, the first ultrasonic element 60 may be arranged on the outer wall surface opposite to the inner wall surface that contacts the fluid in the flow path, for example, on the outer wall surface 312A of the first fixed wall 312. This makes it easy to incorporate the first ultrasonic element 60 into the fluidic device 10.

[0049] In this embodiment, the separation section 30 has a first recess 313 that is concave in a direction away from the flow path along the second axis L2, i.e., in a direction away from the first fixed wall 312, and the first movable wall 311 is arranged opposite a bottom surface 313A of the first recess 313 and can move back and forth within the first recess 313, and the first movable section 314 is arranged within the first recess 313 between the bottom surface 313A of the first recess 313 and the first movable wall 311. This allows the first movable wall 311 to be advanced and retreated in the Y direction with the bottom surface 313A of the first recess 313 as a reference position, and the position of the first movable wall 311 can be easily identified.

[0050] In this embodiment, a second ultrasonic element 70 is further provided, which is disposed at a position different from the first ultrasonic element 60 and generates a second standing wave SW2 along a third axis L3 that intersects (is perpendicular to) the first axis L1. This allows the particles in the fluid to be trapped at the intersection of the node of the first standing wave SW1 and the node of the second standing wave SW2. In other words, it is possible to restrict the movement of the trapped particles in both the Y direction and the Z direction, allowing a concentrated fluid with a high particle concentration to flow out of the first outlet channel 40.

[0051] [Second embodiment] In the above first embodiment, a configuration is exemplified in which a first recess 313 is provided on the -Y side surface of the separation portion 30, and a first movable portion 314 is provided within the first recess 313 so as to connect between the bottom surface 313A of the first recess 313 and the first movable wall 311. In contrast to this, in the second embodiment, the arrangement structure of the first movable wall 311 and the first movable portion 314 is different from that of the first embodiment. In the following description, the same reference numerals will be used to designate items that have already been described, and their description will be omitted or simplified.

[0052] FIG. 7 is a schematic cross-sectional view of the separation section 30 of the fluidic device 10A of the second embodiment cut along a plane parallel to the YZ plane. In this embodiment, as shown in FIG. 7, a hole 316 is provided on the −Y side surface of the separation section 30, penetrating from the inner wall surface 315A to the outer wall surface 315B of the separation section 30. When viewed from the Y direction, the outer peripheral shape of the hole 316 and the first movable wall 311 have substantially the same shape, and the first movable wall 311 can advance and retreat relative to the hole 316 . A gap of a predetermined dimension is provided between the first movable wall 311 and the hole 316, and a flexible sealing member 317 made of, for example, resin is provided to close this gap. The sealing member 317 can prevent the fluid from leaking out of the flow path of the separation unit 30 to the outside.

[0053] In the present embodiment, a first movable part 314 that moves the first movable wall 311 forward and backward is provided on the outside of the separation unit 30. In the first embodiment, the first movable part 314 is provided inside the first recess 313, and therefore needs to be configured with a size that fits within the first recess 313. However, in the present embodiment, the first movable part 314 is provided outside the separation unit 30, which improves the degree of freedom in selecting the first movable part 314. For example, a base substrate 319 is fixed to an outer wall surface 315B on the -Y side of the separation unit 30 via a spacer 318. Then, a configuration in which the first movable part 314 is provided between this base substrate 319 and the first movable wall 311 can be exemplified. In this case, compared to the first embodiment, a larger space can be provided for arranging the first movable part 314, improving the degree of freedom of the first movable part 314. For example, the first movable part 314 may be configured to convert the rotational force of a drive motor into the Y direction using multiple gears, thereby moving the first movable wall 311 back and forth in the Y direction. Alternatively, the first movable wall 311 may be connected to a piston inserted in a cylinder, and the piston may be moved back and forth in the Y direction by controlling the internal pressure in the cylinder. Furthermore, similar to the first embodiment, the first movable wall 311 may be moved back and forth by a piezoelectric actuator.

[0054] Furthermore, this embodiment illustrates a configuration in which the first ultrasonic element 60 is disposed on the first movable wall 311. In this embodiment, a seal member 317 is disposed between the first movable wall 311 and the hole 316, thereby preventing the fluid from entering the side opposite the flow path (-Y side) of the first movable wall 311. Therefore, the wiring and control circuit of the first ultrasonic element 60 can be disposed on the -Y side of the first movable wall 311 without a waterproof mechanism. The first ultrasonic element 60 may be located on the first fixed wall 312 side, as in the first embodiment. The other configurations and the method of driving the fluidic device 10A are the same as those in the first embodiment.

[0055] [Effects of this embodiment] In this embodiment, the separation unit 30 (flow path) has, on its -Y side, an inner wall surface 315A that contacts the fluid, and an outer wall surface 315B opposite to the inner wall surface 315A, and has a hole 316 that penetrates from the inner wall surface 315A to the outer wall surface 315B along the second axis L2. A seal member 317 is provided between the first movable wall 311 and the hole 316 to provide a seal. The first movable part 314 is disposed on the opposite side of the first movable wall 311 from the flow path. Even with this configuration, like the first embodiment, the first movable wall 311 can be advanced and retreated in the Y direction, and the same effects as those of the first embodiment described above can be achieved. Furthermore, in this embodiment, the first movable part 314 is not provided inside the flow channel, so there is a high degree of freedom in designing the first movable part 314, and the first movable part 314 can be of a desired size.

[0056] In this embodiment, the first ultrasonic element is disposed on the first movable wall 311. In this embodiment, as described above, the sealing member 317 prevents fluid from entering the -Y side of the first movable wall 311, so even if the first ultrasonic element 60 is provided on the first movable wall 311, the wiring structure to the first ultrasonic element 60 can be arranged on the -Y side of the first movable wall 311.

[0057] [Third embodiment] In the first embodiment described above, with respect to the Z direction in which the second standing wave SW2 is formed, the second fixed wall 322A is provided on the -Z side of the separation section 30, and the third fixed wall 322B is provided on the +Z side, but either one of the surfaces facing the Z direction may be configured as a second movable wall that can move back and forth in the Z direction.

[0058] FIG. 8 is a schematic cross-sectional view of the separation section 30 of the fluidic device 10B of the third embodiment, cut along the YZ plane. In this embodiment, similarly to the first embodiment, the separation unit 30 is provided with a first movable wall 311 and a first movable portion 314 on the +Y side in the Y direction, and the flow path width in the Y direction is variable. Furthermore, with respect to the Z direction, instead of the second fixed wall 322A of the first embodiment, a second recess 323 having a configuration similar to that of the first recess 313 is provided on the -Z side, and a second movable wall 321 that can move back and forth in the Z direction is provided in the second recess 323. Second movable portion 324 is provided between bottom surface 323A of second recess 323 and second movable wall 321. As with first movable portion 314, for example, a piezoelectric actuator or the like can be used as second movable portion 324, and application of a drive voltage causes second movable wall 321 to advance and retreat in the Z direction. In the example of FIG. 8, a gap of a predetermined dimension is formed between the second movable wall 321 and the second recess 323, and a configuration is achieved in which a part of the fluid flowing through the flow path can enter the second recess 323. In this embodiment, the second ultrasonic element 70 is disposed on the third fixed wall 322B on the +Z side of the separation unit 30.

[0059] In this embodiment, a second movable part 324 is provided in the second recess 323 to move the second movable wall 321, and the same configuration as the first movable wall 311, first recess 313, and first movable part 314 of the first embodiment is exemplified, but the second embodiment may have a configuration similar to that of the second embodiment. For example, a hole penetrating from the inside to the outside may be provided on the -Z side of the separation unit 30, and a second movable wall 321 that can advance and retreat relative to the hole may be provided. In this case, a seal member is provided between the second movable wall 321 and the hole to prevent fluid from leaking out from the hole. In this configuration, the second movable portion 324 that moves the second movable wall 321 is not subject to size restrictions, and the degree of freedom in designing the second movable portion 324 can be improved.

[0060] FIG. 9 is a block diagram showing a schematic configuration of a controller 80A and a functional configuration of a processor 842 according to the third embodiment. In this embodiment, the controller 80A includes a first ultrasonic control circuit 81, a second ultrasonic control circuit 82A, a first movable control circuit 83, and a control unit 84, as well as a second movable control circuit 85.

[0061] The second ultrasonic control circuit 82A of the present embodiment includes a second transmission circuit 821A and a second detection circuit 822. Here, similar to the first transmission circuit 811 of the first embodiment, the second transmission circuit 821A of the present embodiment generates a drive voltage signal of a predetermined drive frequency and outputs it to the second ultrasonic element 70. Therefore, the second frequency of the ultrasonic waves output from the second ultrasonic element 70 is a predetermined fixed frequency.

[0062] The second movable control circuit 85 controls the drive voltage (second movable control signal) for driving the second movable portion 324, and moves the second movable wall 321 forward and backward in the Z direction.

[0063] Similar to the first embodiment, the control unit 84 of this embodiment is configured by a general computer including a memory unit 841 and a processor 842. In this embodiment, the processor 842 functions as a first continuous wave generation unit 842A, a first movable adjustment unit 842B, a first standing wave condition determination unit 842C, a second continuous wave generation unit 842D, and a second standing wave condition determination unit 842E, and also functions as a second movable adjustment unit 842F.

[0064] In the present embodiment, the second transmission command output from the second continuous wave generating unit 842D to the second transmission circuit 821 does not include a frequency command value. Therefore, as described above, ultrasonic waves of the fixed second frequency are transmitted from the second ultrasonic element 70.

[0065] Instead, the second movable adjustment unit 842F outputs a second movable command including a drive command value for the second movable unit 324 to the second movable control circuit 85. As a result, a second movable control signal corresponding to the drive command value is output from the second movable control circuit 85 to the second movable unit 324, and the second movable unit 324 moves the second movable wall 321 along the Z direction by a drive amount corresponding to the drive command value based on the second movable command.

[0066] The second standing wave condition determination unit 842E of this embodiment determines whether or not the second standing wave SW2 is generated based on the detection value of the second detection circuit 822 when the second movable wall 321 is advanced or retreated. The second standing wave condition determination unit 842E also identifies the position of the second movable wall 321 at the timing when it is determined that the second standing wave SW2 is generated.

[0067] FIG. 10 is a flowchart showing a control method for the fluidic device 10B of this embodiment. FIG. 11 is a flowchart showing the details of the sound field adjustment process of FIG. In this embodiment, as shown in FIG. 10, the fluid device 10B is controlled in a manner substantially similar to that of the first embodiment, and first, the sound field adjustment process of step S1A is performed. 11, in this sound field adjustment process, first, the second continuous wave generating unit 842D outputs a second transmission command to the second transmitting circuit 821. As a result, the second ultrasonic element 70 transmits ultrasonic waves of a predetermined second frequency (fixed frequency) into the flow path (step S21). Next, the second movable adjustment unit 842F outputs a second movable command including a drive command value to the second movable control circuit 85, and changes the drive command value to move the second movable wall 321 forward and backward in the Z direction (step S22). Then, the second standing wave condition determination unit 842E determines the position of the second movable wall 321 at the time when the second standing wave SW2 is formed based on the detection value of the second detection circuit 822 when the position of the second movable wall 321 is changed in step S22 (step S23).

[0068] Thereafter, steps S13 to S15 similar to those in the first embodiment are carried out to identify the position of the first movable wall 311 that satisfies the condition for forming the first standing wave SW1.

[0069] 10, in this embodiment, after step S1A, in step S2, the first movable wall 311 is moved to the position specified in step S15, as in the first embodiment. Furthermore, in this embodiment, the second movable adjustment part 842F moves the second movable wall 321 to the position specified in step S23 (step S2A).

[0070] Thereafter, similarly to the first embodiment, the first continuous wave generating unit 842A and the second continuous wave generating unit 842D perform a process of transmitting continuous waves (ultrasound waves) (step S3A). Note that in this embodiment, as described above, the second continuous wave generating unit 842D causes the second ultrasonic element 70 to transmit ultrasound waves of a preset second frequency. The subsequent processing is the same as in the first embodiment.

[0071] [Effects of this embodiment] In the fluidic device 10B of this embodiment, of a pair of flow path walls in the ±Z direction that face each other along the third axis L3 of the separation section 30 that constitutes the flow path, a second movable wall 321 is provided on the -Z side, and a second movable section 324 is provided that moves the second movable wall 321 along the third axis L3 that is parallel to the Z direction. This allows the flow path width between the second movable wall 321 and the third fixed wall 322B to be changed to match the conditions of the second standing wave SW2 with respect to the frequency of the ultrasonic waves output from the second ultrasonic element 70. Therefore, the second transmission circuit 821 of the second ultrasonic control circuit 82 only needs to control the transmission of ultrasonic waves of a preset fixed second frequency, which simplifies the circuit configuration and contributes to reducing the cost of the device. That is, in this embodiment, the circuit configurations of both the first transmission circuit 811 and the second transmission circuit 821 can be simplified.

[0072] [Variations] The present invention is not limited to the above-described embodiments, and the present invention includes configurations obtained by modifications, improvements, and appropriate combinations of the embodiments within the scope that can achieve the object of the present invention.

[0073] (Variation 1) In the first embodiment, as an example of arrangement when bulk type ultrasonic elements are used as the first ultrasonic element 60 and the second ultrasonic element 70, an example has been described in which the first ultrasonic element 60 is arranged on the outer wall surface 312A of the first fixed wall 312 and the second ultrasonic element 70 is arranged on the outer wall surface 322C of the second fixed wall 322A, but this is not limiting. When bulk type ultrasonic elements are used, the first ultrasonic element 60 and the second ultrasonic element 70 may be arranged at positions away from the separation unit 30 as long as they are positions where ultrasonic waves of the separation unit 30 can propagate. Furthermore, in the third embodiment, the first ultrasonic element 60 and the second ultrasonic element 70 each transmit ultrasonic waves at a fixed frequency, but the first ultrasonic element 60 and the second ultrasonic element 70 may transmit ultrasonic waves at the same frequency. Furthermore, when a bulk type ultrasonic element is used to form a first standing wave SW1 and a second standing wave SW2 of ultrasonic waves at the same frequency, only the first ultrasonic element 60 may be disposed, in which case the second ultrasonic element 70 can be eliminated.

[0074] [Variation 2] In the above embodiment, an example in which the first standing wave SW1 and the second standing wave SW2 are formed in the separator 30 has been described, but the present invention is not limited to this. FIG. 12 is a cross-sectional view showing a part of a fluidic device 10C according to the second modification. For example, as shown in FIG. 12, a third ultrasonic element 90 may be further provided in the inflow channel 20, and configured to transmit ultrasonic waves along a fourth axis L4 perpendicular to the first axis L1 of the inflow channel 20, thereby forming a third standing wave SW3 within the inflow channel 20. In this case, a configuration may be adopted in which a third movable wall 211 is provided that is movable forward and backward along the fourth axis L4 relative to the inflow channel 20. As a configuration for driving the third movable wall 211, for example, similar to the first movable wall 311 of the first embodiment, a third recess 213 that is recessed in a direction away from the inflow channel 20 along the fourth axis L4, and a third movable portion 214 is provided between the third recess 213 and the third movable wall 211, may be provided in the inflow channel 20. Note that, as with the first movable wall 311 of the second embodiment, a configuration may be adopted in which a hole penetrating the inside and outside of the inflow channel is provided in one surface of the inflow channel 20, the third movable wall 211 is movable forward and backward relative to the hole, and the gap between the third movable wall 211 and the hole is sealed with a sealing member.

[0075] [Variation 4] In the first to third embodiments, a configuration in which the second ultrasonic element 70 is provided has been exemplified, but a configuration in which the second ultrasonic element 70 is not provided and only the first standing wave SW1 is formed by the first ultrasonic element 60 may also be used.

[0076] [Variation 5] In the first embodiment, a configuration has been described in which a gap is provided between the first recess 313 and the first movable wall 311, and fluid enters the first recess 313 through the gap, but the present invention is not limited to this. For example, a configuration may be adopted in which the seal member 317 used in the second embodiment is disposed between the first recess 313 and the first movable wall 311 to close the gap.

[0077] Summary of this disclosure A fluidic device according to a first aspect of the present disclosure is a fluidic device that uses ultrasound to capture microparticles in a fluid, and includes: a flow path extending along a first axis through which a fluid containing the microparticles flows along the first axis; a first ultrasonic element disposed in the flow path and generating a standing wave within the flow path along a second axis that intersects the first axis; a movable wall provided on at least one of a pair of flow path walls that face each other along the second axis in the flow path; and a movable part that moves the movable wall along the second axis.

[0078] This allows the flow channel width to be varied by advancing and retracting the movable wall along the second axis. Therefore, even in cases where the flow channel width of the fluidic device includes manufacturing errors, where there is variation in the frequency of the ultrasonic waves transmitted from the first ultrasonic element, where there is a change in the speed of sound due to a change in the temperature of the fluid, or where there is a change in the flow channel width due to thermal expansion of the fluidic device, the flow channel width can be varied so that a standing wave is formed along the second axis. Furthermore, in cases where a control circuit capable of varying the frequency of the first ultrasonic element is used, the circuit configuration of the control circuit becomes complex and the manufacturing costs increase, whereas in this embodiment, a simple circuit configuration that outputs a single frequency can be used, thereby reducing manufacturing costs.

[0079] In the fluidic device of this aspect, the first ultrasonic element is preferably disposed at a position facing the movable wall across the flow channel. As a result, when the first ultrasonic element is a thin-film ultrasonic element, the ultrasonic waves output from the ultrasonic transmission surface of the first ultrasonic element can be propagated directly into the fluid, and the fine particles can be captured with a high acoustic radiation force.

[0080] In the fluidic device of this aspect, the first ultrasonic element is preferably disposed on an outer wall surface of the flow channel opposite to an inner wall surface that comes into contact with the fluid. In this way, by providing the first ultrasonic element on the outer wall surface of the flow channel, it becomes easy to incorporate the ultrasonic element into the fluidic device.

[0081] In the fluidic device of this aspect, the first ultrasonic element may be configured to be disposed on the movable wall. Even when the first ultrasonic element is placed on the movable wall, as described above, the ultrasonic waves output from the ultrasonic transmitting surface of the first ultrasonic element can be propagated directly into the fluid, and the particles can be captured with a high acoustic radiation force.

[0082] In the fluidic device of this aspect, it is preferable that the flow path has a recess that is concave in a direction away from the flow path along the second axis, the movable wall is arranged opposite the bottom surface of the recess and is capable of moving forward and backward within the recess, and the movable part is arranged within the recess between the bottom surface of the recess and the movable wall. This allows the width of the flow path in which the standing wave is formed to be changed by moving the first movable wall relative to the first recess. In addition, the first movable wall can be moved forward and backward along the first axis with the bottom surface of the first recess as a reference position, making it easy to identify the position of the first movable wall.

[0083] In the fluid device of this aspect, the flow path has an inner wall surface that contacts the fluid and an outer wall surface opposite the inner wall surface, and a part of the flow path has a hole that penetrates from the inner wall surface to the outer wall surface along the second axis, and a sealing member is further provided to seal between the movable wall and the hole, and the movable part may be configured to be positioned on the opposite side of the movable wall from the flow path. Even with this configuration, the width of the flow path for forming standing waves can be changed by moving the first movable wall relative to the hole. Furthermore, since the movable part is not provided inside the flow path, there is a high degree of freedom in designing the first movable part, and a movable part of a desired size can be used.

[0084] The fluidic device of this aspect further comprises a second ultrasonic element that is disposed at a position different from the first ultrasonic element and generates a standing wave along a third axis that intersects with the first axis. This allows the two standing waves to trap particles in the fluid at desired positions, improving the efficiency of trapping particles in the fluidic device.

[0085] In the fluidic device of this aspect, it is preferable that the device further comprises a second movable wall provided on at least one of a pair of flow path walls opposing each other along the third axis of the flow path, and a second movable part that moves the second movable wall along the third axis. As a result, with regard to the standing wave formed by the second ultrasonic element, the flow path width can be changed so that a standing wave is formed by moving the second movable wall back and forth along the third axis using the second movable part. In addition, there is no need to use a complex and costly control circuit that varies the frequency of the second ultrasonic element, and the second ultrasonic element can be controlled by a control circuit with a low manufacturing cost and a simple configuration. [Explanation of symbols]

[0086] 10, 10A, 10B, 10C...fluidic device, 20...inlet flow path, 30...separation section, 40...first outlet flow path, 50...second outlet flow path, 60...first ultrasonic element, 70...second ultrasonic element, 80, 80A...controller, 81...first ultrasonic control circuit, 82...second ultrasonic control circuit, 82A...second ultrasonic control circuit, 83...first movable control circuit, 84...control section, 85...second movable control circuit, 311...first movable wall, 312...first fixed wall, 313...first recess, 314...first movable section, 316...hole section, 317 ...Sealing member, 318...Spacer, 319...Base substrate, 321...Second movable wall, 323...Second recess, 324...Second movable part, 811...First transmitting circuit, 812...First detection circuit, 821...Second transmitting circuit, 821A...Second transmitting circuit, 822...Second detection circuit, 841...Memory unit, 842...Processor, 842A...First continuous wave generating unit, 842B...First movable adjustment unit, 842C...Second standing wave condition determination unit, 842D...Second continuous wave generating unit, 842E...Second standing wave condition determination unit, 842F...Second movable adjustment unit.

Claims

1. A fluidic device that uses ultrasound to capture particles in a fluid, a flow channel extending along a first axis, through which a fluid containing the particulates flows along the first axis; a first ultrasonic element disposed in the flow path and generating a standing wave within the flow path along a second axis that intersects the first axis; a movable wall provided on at least one of a pair of flow path walls that face each other along the second axis in the flow path; a movable portion that moves the movable wall along the second axis; A fluidic device comprising:

2. The first ultrasonic element is disposed at a position facing the movable wall across the flow path. The fluidic device according to claim 1 .

3. The first ultrasonic element is disposed on an outer wall surface of the flow channel opposite to an inner wall surface that contacts the fluid. The fluidic device according to claim 1 .

4. The first ultrasonic element is disposed on the movable wall. The fluidic device according to claim 1 .

5. the flow channel includes a recess that is concave along the second axis in a direction away from the flow channel; the movable wall is disposed opposite a bottom surface of the recess and is capable of advancing and retreating within the recess, The movable portion is disposed within the recess between the bottom surface of the recess and the movable wall. The fluidic device according to claim 1 .

6. the flow path includes an inner wall surface in contact with the fluid and an outer wall surface opposite to the inner wall surface, a hole portion that penetrates from the inner wall surface to the outer wall surface along the second axis in a part of the flow path; a sealing member that seals between the movable wall and the hole is further provided, The movable portion is disposed on the opposite side of the movable wall from the flow path. The fluidic device according to claim 1 .

7. Further, a second ultrasonic element is disposed at a position different from the first ultrasonic element and generates a standing wave along a third axis intersecting the first axis. The fluidic device according to claim 1 .

8. a second movable wall provided on at least one of a pair of flow path walls opposing each other along the third axis of the flow path; a second movable portion that moves the second movable wall along the third axis, The fluidic device according to claim 7 .

Images