JP2024005405A - Fluid device and method for controlling fluid device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fluid device that can measure the flow rate of fluid, and a method for controlling a fluid device.

SOLUTION: A fluid device comprises: a flow channel 20 through which fluid flows; an ultrasonic wave element array 30 that is provided on the flow channel 20 and includes a plurality of ultrasonic wave elements 33 arranged in array; a drive control unit that controls the drive of the plurality of ultrasonic wave elements 33; and a flow rate measurement unit that measures the flow rate of the fluid. The drive control unit causes a first ultrasonic wave element 33A and a second ultrasonic wave element 33B in the ultrasonic wave element array 30, which are arranged at positions different from each other in a flowing direction of the fluid, to transmit and receive ultrasonic waves to and from each other through the fluid. The flow rate measurement unit measures the flow rate based on a difference between a first ultrasonic wave propagation time from the first ultrasonic wave element 33A to the second ultrasonic wave element 33B and a second ultrasonic wave propagation time from the second ultrasonic wave element 33B to the first ultrasonic wave element 33A.

SELECTED DRAWING: Figure 2

COPYRIGHT: (C)2024,JPO&INPIT

Description

The present invention relates to a fluidic device and a method of controlling a fluidic device.

2. Description of the Related Art Conventionally, devices are known that separate fine particles dispersed in a fluid from the fluid. For example, the fluidic device disclosed in Patent Document 1 includes a substrate in which a flow path is formed and an ultrasonic element provided on the substrate. Ultrasonic waves transmitted from the ultrasonic element are propagated into the flow channel through the substrate and generate standing waves in the fluid within the flow channel. The particles in the fluid are focused in a predetermined range within the flow path due to the pressure gradient of the fluid formed by the standing waves, and a concentrated liquid containing the focused particles is collected.

International Publication No. 2005/058459

In a fluid device such as that described in Patent Document 1, in order to appropriately set acoustic force on particles, it is desirable to acquire fluid flow velocity information in an acoustic force generation region. However, when a conventional flow meter is provided in a fluid device, there is a problem in that the entire fluid device becomes larger.

A fluidic device according to a first aspect of the present disclosure includes: a flow path through which a fluid flows; an ultrasonic element group including a plurality of ultrasonic elements provided in the flow path and arranged in an array; The drive control unit includes a drive control unit that controls the drive of the ultrasonic element, and a flow velocity measurement unit that measures the flow velocity of the fluid, and the drive control unit is located at different positions in the flow direction of the fluid among the group of ultrasonic elements. The flow rate measurement unit transmits and receives ultrasonic waves from the first ultrasonic element to the second ultrasonic element through the fluid between any first ultrasonic element and second ultrasonic element arranged. The flow velocity is measured based on a difference between a first ultrasonic propagation time to the sonic element and a second ultrasonic propagation time from the second ultrasonic element to the first ultrasonic element.

A fluid device control method according to a second aspect of the present disclosure is a fluid device control method that measures a flow rate, and the fluid device includes a flow path through which a fluid flows, and an array of the fluid devices provided in the flow path. an ultrasonic element group including a plurality of ultrasonic elements disposed in the ultrasonic element group, a drive control section that controls driving of the plurality of ultrasonic elements, and a flow velocity measurement section that measures the flow velocity of the fluid, The control unit transmits ultrasound through the fluid between arbitrary first and second ultrasound elements that are arranged at different positions in the flow direction of the fluid among the ultrasound element group. transmitting and receiving signals to and from each other, and the flow rate measurement unit detecting a first ultrasonic propagation time from the first ultrasonic element to the second ultrasonic element and a time from the second ultrasonic element to the first ultrasonic element. and measuring the flow velocity based on a difference from a second ultrasound propagation time.

FIG. 1 is a block diagram showing a fluid device according to a first embodiment. FIG. 1 is a cross-sectional view schematically showing a flow path in the fluid device of the first embodiment. FIG. 2 is a plan view showing an ultrasonic element array in the fluidic device of the first embodiment. FIG. 4 is a sectional view taken along the line AA in FIG. 3. 1 is a flowchart for explaining the flow velocity measurement method of the first embodiment. FIG. 2 is a cross-sectional view schematically showing a flow path for explaining the flow rate measurement method of the first embodiment. 1 is a flowchart for explaining an example of a method for controlling a fluidic device according to the first embodiment. FIG. 3 is a cross-sectional view schematically showing a flow path in a fluid device according to a second embodiment. FIG. 7 is a block diagram showing a fluid device according to a third embodiment.

[First embodiment]
The fluid device 10 of the first embodiment will be described.
(Configuration of fluid device 10)
As shown in FIGS. 1 and 2, the fluidic device 10 includes a flow path 20 through which a fluid S containing particles M flows, and an ultrasonic element array 30 (corresponding to a group of ultrasonic elements) provided in the flow path 20. , and a control unit 40 that controls the ultrasonic element array 30.

The fluid device 10 of the present embodiment makes it possible to collect the concentrated liquid Sc, which is the fluid S in which the particles M are concentrated, by capturing the particles M in the fluid S flowing through the flow path 20 using ultrasound. Further, the fluid device 10 of this embodiment measures the flow rate of the fluid S flowing through the flow path 20, and sets or adjusts the output of the ultrasonic wave based on the measured flow rate.
Note that the fluid S is not particularly limited, but may be any liquid such as water or blood. The fine particles M are, for example, fine fibers or cells, although they are not particularly limited. Furthermore, in FIG. 2, for the sake of simplicity, it is assumed that the plurality of particles M have the same size, but particles M of various sizes are dispersed in the fluid S.

As shown in FIG. 2, the flow path 20 includes an inlet 21 into which a fluid S in which fine particles M are dispersed flows, a flow path body 22 in which a standing wave SW is formed by ultrasonic waves, and a flow path body 22 in which a standing wave SW is formed by ultrasonic waves. It has a concentration outlet 23 for selectively discharging the fluid S (ie, the concentrate Sc) containing the concentrated particles M, and a discharge port 24 for selectively discharging the fluid Sr other than the concentrate Sc.
This channel 20 is formed, for example, in a channel substrate 25. The channel substrate 25 includes a base substrate having a groove corresponding to the channel 20 and a lid substrate covering the groove. Although these substrates are not particularly limited, for example, glass substrates and silicon substrates can be used.
Further, the channel main body 22 has a first channel wall 221 and a second channel wall 222 that face each other in an arbitrary channel width direction orthogonal to the flow direction of the fluid S. At 221, an ultrasonic element array 30 is provided.
Note that in the following, the flow direction of the fluid S in the flow path 20 is referred to as the X direction, and the direction from the first flow path wall 221 to the second flow path wall 222 is referred to as the Y direction, which is orthogonal to each of the X direction and the Y direction. Let the direction be the Z direction. The channel width r between the first channel wall 221 and the second channel wall 222 is a known value.

The ultrasonic element array 30 constitutes a part of the first channel wall 221 of the channel 20 and faces the fluid S in the channel body 22. This ultrasonic element array 30 includes a plurality of ultrasonic elements 33 arranged in an array.

The specific configuration of the ultrasonic element array 30 will be briefly described below. As shown in FIG. 3, the ultrasonic element array 30 includes a plurality of ultrasonic elements 33 by an element substrate 31 arranged along the XZ plane and a plurality of piezoelectric elements 32 provided on the element substrate 31. It is configured as follows.

As shown in FIG. 4, the element substrate 31 includes a substrate main body 311 and a vibrating membrane 312 provided on the substrate main body 311. The substrate body 311 is provided with a plurality of openings 311A arranged two-dimensionally in the XZ plane, and the vibrating membrane 312 covers each opening 311A of the element substrate 31. An acoustic layer may be provided in the opening 311A. A portion of the vibrating membrane 312 that overlaps with the opening 311A in plan view constitutes a vibrating section 312A that transmits ultrasonic waves.

The piezoelectric element 32 is provided at a position overlapping each vibrating section 312A. This piezoelectric element 32 is constructed by laminating a first electrode 321, a piezoelectric film 322, and a second electrode 323 on a vibrating membrane 312 in this order.
As shown in FIG. 3, the first electrode 321 is formed in a straight line along the Z direction, and is connected to the control unit 40 via electrode terminals 321P at both ends. The second electrode 323 is formed in a straight line along the X direction, and is connected to the common electrode line 324. The common electrode line 324 is connected to the control unit 40 via electrode terminals 324P at both ends. The piezoelectric film 322 is formed of a thin film of piezoelectric material such as PZT (lead zirconate titanate).

The ultrasonic elements 33 in the ultrasonic element array 30 include a vibrating section 312A and a piezoelectric element 32 provided on the vibrating section 312A. In the ultrasonic element 33, when a drive signal is input to the piezoelectric element 32, the piezoelectric film 322 of the piezoelectric element 32 expands and contracts, so that the vibrating part 312A bends and vibrates in the thickness direction of the element substrate 31. The bending vibration of the vibrating portion 312A is converted into a compressional wave of the fluid S, so that the ultrasonic wave is propagated from the ultrasonic element 33 to the fluid S.
In this embodiment, the plurality of ultrasonic elements 33 arranged in the Z direction constitute a one-channel element row CH.

In the ultrasonic element array 30 described above, the plurality of ultrasonic elements 33 have the same configuration, but the first ultrasonic element 33A and the second ultrasonic element 33B differ in operation controlled by the control unit 40. , and a standing wave generating element 33C. The first ultrasonic element 33A and the second ultrasonic element 33B transmit and receive ultrasonic waves to perform ultrasonic flow velocity measurement, and the standing wave generating element 33C forms a standing wave SW in the fluid S. Send ultrasound to.
Here, as shown in FIG. 2, the first ultrasonic element 33A is arranged at one end (upstream end) in the X direction of the ultrasonic element array 30, and the second ultrasonic element 33B is , are arranged at the other end (downstream end) of the ultrasonic element array 30 in the X direction. A plurality of standing wave generating elements 33C arranged in the X direction are arranged between the first ultrasonic element 33A and the second ultrasonic element 33B. Note that the inter-element distance d in the X direction between the first ultrasonic element 33A and the second ultrasonic element 33B (see FIG. 6) is known.
Hereinafter, the element row CH by the first ultrasonic element 33A is element row CH-A, the element row CH by the second ultrasonic element 33B is element row CH-B, and the element row CH by the standing wave generating element 33C is element row CH. -C may be written (see Figure 1).

As shown in FIG. 1, the control unit 40 includes a circuit unit 41 that drives the ultrasonic element array 30, a processor 42 that performs various controls, and a memory 43. Further, although not shown, the control unit 40 may include a ground circuit for the ultrasonic element array 30.

The circuit section 41 includes a selection circuit 411, a transmission circuit 412, a reception circuit 413, a TOF calculation circuit 414, and a drive circuit 415.
The selection circuit 411 switches the connection between the transmitting circuit 412 and the receiving circuit 413 based on the control of a drive control section 421, which will be described later. Further, the selection circuit 411 can connect the first ultrasonic element 33A (element column CH-A) or the second ultrasonic element 33B (element column CH-B) to the transmitting circuit 412 or the receiving circuit 413.

The transmitting circuit 412 outputs a drive signal to the first ultrasonic element 33A (element column CH-A) or the second ultrasonic element 33B (element column CH-B) via the selection circuit 411. Ultrasonic waves are transmitted from the first ultrasonic element 33A or the second ultrasonic element 33B.

The receiving circuit 413 converts the received signal input from the first ultrasonic element 33A or the second ultrasonic element 33B via the selection circuit 411 into a digital signal, removes noise components, and amplifies it to a desired signal level. Perform various signal processing such as Further, the receiving circuit 413 outputs the signal-processed received signal to the TOF calculation circuit 414.

The TOF calculation circuit 414 determines the flight of the ultrasonic wave in the flow path 20 based on the time difference between the timing signal input in synchronization with the output of the drive signal from the transmission circuit 412 and the reception signal input from the reception circuit 413. Calculate the time (TOF value).

The drive circuit 415 outputs a drive signal of a predetermined frequency f for generating a standing wave SW to the standing wave generating element 33C. As a result, an ultrasonic wave having a predetermined frequency f is transmitted from the standing wave generating element 33C. Note that the amplitude of the drive signal (drive voltage Vd) corresponds to the amplitude of the ultrasonic wave transmitted from the standing wave generation element 33C.

The processor 42 functions as a drive control section 421 and a flow rate measurement section 422 by executing a program stored in the memory 43. The drive control unit 421 controls the drive of each ultrasonic element 33 in the ultrasonic element array 30. The flow rate measurement unit 422 measures the flow rate (that is, calculates the flow rate V) based on the TOF value calculation result by the TOF calculation circuit 414. Details of the drive control section 421 and the flow rate measurement section 422 will be described later.

The memory 43 is a storage device that stores various programs and various data. For example, the memory 43 stores the flow path width r of the flow path 20, the sound speed C in the fluid, the inter-element distance d, and the like as information required for the calculation in the flow velocity measuring section 422. Further, the memory 43 stores, as information for capturing the particulates M in the fluid S, a drive table or a calculation coefficient indicating the correspondence between the flow velocity V and the drive voltage Vd. It is preferable that the drive table or calculation coefficient is stored for each size of the particle M to be captured. Note that the size of the fine particles M may be divided into arbitrary numerical ranges such as the size and volume of the fine particles M.

(Control mechanism of fluidic device)
In the fluidic device 10 of this embodiment, a mechanism for concentrating particulates M in the fluid S will be described.
The ultrasonic waves transmitted from the standing wave generating element 33C are radially diffused into the fluid S as spherical waves. By repeating the reflection between the flow path wall 222 and the second flow path wall 222, a standing wave SW is generated within the flow path main body 22.
Here, the frequency of the ultrasonic wave transmitted from the standing wave generation element 33C is f1, the mode order of the standing wave SW is n, the sound speed in the fluid S is C, and the width of the flow path 20 in the Y direction is r. When the following equation (1) is satisfied, a standing wave SW is formed.

As shown in FIG. 2, when a first-order mode standing wave SW occurs, nodes appear at the center of the channel body 22 in the channel width direction, and nodes appear at both ends of the channel body 22 in the channel width direction. A belly appears. In this case, the particles M having a higher acoustic impedance than the fluid S reach the nodes of the standing wave SW, that is, the central part of the channel body 22 in the channel width direction, while the fluid S flows through the channel body 22. Focus (acoustic focus). Then, the fluid S (concentrated liquid Sc) containing the focused particles M is discharged from the concentration outlet 23, and the other fluids are discharged from the discharge port 24. That is, the concentrated liquid Sc is separated.
In addition, in this embodiment, in order to simplify the explanation, an example in which a first-order mode standing wave SW is generated is used, but the mode order of the standing wave SW is not particularly limited.

Here, the capturing force of the particle M by the fluid device 10 determines the lower limit of the size of the particle M that can be captured by acoustic focusing, and the larger the capturing force is, the smaller the particle M can be captured. Become.
The ability of the fluidic device 10 to capture the particles M depends on the amplitude of the drive signal (that is, the drive voltage Vd) and the flow rate of the fluid S. If the drive voltage Vd is adjusted at a predetermined flow rate so that particles M of a desired size can be captured, if the flow rate changes due to fluctuations in pump output, etc., the range of sizes of particles M that can be captured will change. Change. For example, when the flow speed becomes faster, the fluid S passes through the formation range of the standing wave SW before particles M of a desired size are sufficiently focused, making it difficult to sufficiently capture particles M of a desired size. I can't. On the other hand, when the flow velocity becomes slower, while the fluid S passes through the formation range of the standing wave SW, not only the particles M of the desired size but also smaller particles M are focused, and the particles M that can be captured are The accuracy of the magnitude of is reduced.
Therefore, in this embodiment, the flow rate of the fluid S is measured as described later, and the drive voltage Vd is adjusted according to the measured flow rate (flow rate V), thereby stably producing particles M of a desired size. Make it captureable.

(Flow velocity measurement method)
A flow rate measuring method in the fluid device 10 of this embodiment will be explained using the flowchart of FIG. 5. Note that the drive control unit 421 of this embodiment switches to the measurement mode when measuring the flow velocity.

First, under the control of the drive control unit 421, the forward propagation time Tab (first ultrasonic propagation time), which is the TOF value from the first ultrasonic element 33A to the second ultrasonic element 33B, is measured (step S11).
Specifically, the selection circuit 411 connects the first ultrasonic element 33A (element row CH-A) and the transmitting circuit 412, and connects the second ultrasonic element 33B and the receiving circuit 413. do. Then, the transmitting circuit 412 outputs a drive signal to the first ultrasonic element 33A for a predetermined period of time.
As a result, the ultrasonic waves (burst waves) transmitted from the first ultrasonic element 33A travel along the flow of the fluid S (flow in the X direction) in the flow path 20, thereby reaching the second flow path wall 222. After being reflected, it is received by the second ultrasonic element 33B (see the solid line arrow in FIG. 6). The TOF calculation circuit 414 calculates the outward propagation time Tab based on the received signal input from the second ultrasonic element 33B via the selection circuit 411 and the reception circuit 413.

Next, under the control of the drive control unit 421, the return propagation time Tba (second ultrasonic propagation time), which is the TOF value from the second ultrasonic element 33B to the first ultrasonic element 33A, is measured (step S12).
Specifically, the selection circuit 411 connects the second ultrasonic element 33B (element row CH-B) and the transmitting circuit 412, and connects the first ultrasonic element 33A and the receiving circuit 413. do. Then, the transmission circuit 412 outputs a drive signal to the second ultrasonic element 33B for a predetermined period of time.
As a result, the ultrasonic wave (burst wave) transmitted from the second ultrasonic element 33B travels against the flow of the fluid S in the flow path 20, and after being reflected by the second flow path wall 222, the ultrasonic wave (burst wave) is transmitted to the first ultrasonic wave. The signal is received by the acoustic wave element 33A (see the dotted arrow in FIG. 6). The TOF calculation circuit 414 calculates the backward propagation time Tba based on the received signal input from the first ultrasonic element 33A via the selection circuit 411 and the reception circuit 413.
Note that the driving voltage Vd and the frequency of the ultrasonic waves used in the measurement mode are not particularly limited.

Thereafter, the flow velocity measuring unit 422 calculates the flow velocity V based on the time difference between the outward propagation time Tab obtained in step S11 and the backward propagation time Tba obtained in step S12 (step S13). Note that this time difference may be a reciprocal difference.

往路伝搬時間Ｔａｂと復路伝搬時間Ｔｂａとの逆数差は、以下の式（４）で表されるため、流速Ｖは、以下の式（５）によって表される。

Specifically, there is a time difference depending on the flow velocity of the fluid S between the forward travel time Tab determined in step S11 and the backward travel time Tba determined in step S12.
For example, the outward propagation time Tab and the return propagation time Tba are expressed by the following equations (2) and (3), respectively. Here, as shown in Figure 6, L (=L/2+L/2) is the ultrasonic propagation distance, C is the sound velocity, V is the flow velocity, and θ is the angle between the channel axis and the ultrasonic propagation axis. It is.

Since the reciprocal difference between the forward propagation time Tab and the backward propagation time Tba is expressed by the following equation (4), the flow velocity V is expressed by the following equation (5).

よって、上記式（５）～（７）によれば、流速Ｖは、以下の式（８）によって表される。

以上により、流速測定部４２２は、上記式（８）を用いて、往路伝搬時間Ｔａｂと復路伝搬時間Ｔｂａとの時間差に基づいた流速Ｖを算出することができる。 Further, as shown in FIG. 6, cos θ in the above equation (5) is expressed by the following equation (6), and the ultrasonic propagation distance L is expressed by the following equation (7). Here, the channel width of the channel 20 is defined as r, and the distance between the first ultrasonic element 33A and the second ultrasonic element 33B on the channel axis is defined as d.

Therefore, according to the above equations (5) to (7), the flow velocity V is expressed by the following equation (8).

As described above, the flow velocity measurement unit 422 can calculate the flow velocity V based on the time difference between the outward propagation time Tab and the return propagation time Tba using the above equation (8).

(Fluid device control method)
An example of a method of controlling the fluid device 10 of this embodiment will be described with reference to the flowchart of FIG. 7. Note that before the flowchart starts, the size of the particles M to be captured may be set to a predetermined size in advance, or may be set according to the user's operation. Furthermore, in this embodiment, for the sake of simplicity of explanation, it is assumed that a predetermined frequency f for generating the standing wave SW is determined in advance.

First, the fluid device 10 measures the flow velocity of the fluid S in response to a user's starting operation or the start of the flow of the fluid S (step S21). Thereby, the current flow velocity of the fluid S is measured. Note that the specific flow rate measurement method is as described above. Further, the value of the flow velocity V measured in step S21 is stored in the memory 43 as the reference flow velocity Vs.

Next, the drive control unit 421 sets the amplitude (drive voltage Vd) of the drive signal output by the drive circuit 415 according to the flow velocity V measured in step S21 (step S22). Thereby, the amplitude of the ultrasonic wave transmitted from the standing wave generating element 33C is set.
For example, the drive control unit 421 specifies a drive table or calculation coefficient corresponding to the size of the particle M to be captured from the memory 43, and based on the specified drive table or calculation coefficient, the flow rate measured in step S21 is determined. The value of the drive voltage Vd corresponding to V is calculated, and the calculated value is set in the drive circuit 415.

After that, the drive control unit 421 switches to the standing wave generation mode and starts forming the standing wave SW in the fluid S (step S23).
Specifically, under the control of the drive control unit 421, the drive circuit 415 generates a drive signal having a predetermined frequency f for generating a standing wave SW in the fluid S and the drive voltage Vd set in step S22. , starts outputting to the standing wave generating element 33C (element array CH-C). As a result, an ultrasonic wave is transmitted from the standing wave generating element 33C, and a standing wave SW is formed in the fluid S. As a result, separation of the concentrated liquid Sc of the fine particles M is started.

Then, the drive control unit 421 determines whether or not a predetermined measurement timing has arrived (step S24), and when determining that the measurement timing has come (step S24; in the case of Yes), the drive control unit 421 forms a standing wave. is stopped (step S25). This measurement timing is not particularly limited, but may be set, for example, at predetermined time intervals.

Next, the drive control unit 421 switches to the measurement mode and measures the flow velocity of the fluid S (step S26) similarly to step S21.
After that, the drive control unit 421 determines whether or not the flow velocity V measured in step S26 matches the reference flow velocity Vs stored in the memory 43 (step S27). Here, "match" is not limited to a complete match, but includes a predetermined error. That is, if |V−Vs| is within a preset error range, it is determined that the two match.

If the determination in step S27 is No, the drive control unit 421 adjusts the drive voltage Vd in the same way as in step S22, according to the flow velocity V measured in step S26 (step S28). Note that, after adjusting the drive voltage Vd, the drive control unit 421 updates the value of the flow velocity V measured in step S26 as the reference flow velocity Vs stored in the memory 43.

If the flow velocity V measured in step S26 is larger than the reference flow velocity Vs, the drive control unit 421 calculates a value larger than the current set value as the drive voltage Vd, and sets the drive voltage to the drive circuit 415. Increase Vd. This increases the speed at which the particles M in the fluid S converge, so that particles M of a desired size can be sufficiently focused while the fluid S passes through the area where the standing wave SW is formed.
On the other hand, if the flow velocity V measured in step S26 is smaller than the reference flow velocity Vs, the drive control unit 421 calculates a value smaller than the current set value as the drive voltage Vd, and sets the drive voltage Vd in the drive circuit 415. Decrease Vd. As a result, the speed at which the particles M in the fluid S are focused is slowed down, so that while the fluid S passes through the area where the standing wave SW is formed, particles M of a desired size can be focused, while particles M of a desired size can be It is also possible to prevent small particles M from being focused.

If the determination in step S27 is Yes, or after step S28, the drive control unit 421 switches to the standing wave generation mode and resumes forming the standing wave SW in the fluid S (step S29). Specifically, under the control of the drive control unit 421, the drive circuit 415 uses a predetermined frequency f for generating a standing wave SW in the fluid S and a drive voltage Vd adjusted in step S28 (or the same value as before stopping). A drive signal having a drive voltage Vd) is started to be output to the standing wave generating element 33C (element column CH-C). As a result, the formation of the standing wave SW in the fluid S is restarted.

After that, the process in the fluidic device 10 returns to step S24. Note that the fluid device 10 may end the flowchart of FIG. 7 when a stop instruction is input by the user's operation or when a predetermined time has elapsed.
As described above, while the flowchart of FIG. 7 continues, the drive voltage is feedback-controlled according to the flow velocity V.

(Operations and effects of this embodiment)
As described above, the fluidic device 10 of this embodiment includes the ultrasonic element array 30 which is a group of ultrasonic elements, and includes the first ultrasonic element 33A and the second ultrasonic element 33B included in the ultrasonic element array 30. The flow velocity V of the fluid S can be measured using this method. That is, the ultrasonic element array 30 for generating acoustic force can also be used for flow velocity measurement. Thereby, flow velocity information of the fluid S in the region where the acoustic force is generated by the ultrasonic element array 30 can be acquired. Furthermore, the overall size of the fluid device 10 can be reduced compared to the case where a conventional flow meter is provided in the fluid device.

In this embodiment, the ultrasonic element array 30 includes a standing wave generating element 33C that is different from the first ultrasonic element 33A and the second ultrasonic element 33B. In such a configuration, the particles M in the fluid S can be captured using the standing wave SW generated by the standing wave generating element 33C. Furthermore, the amplitude of the ultrasonic waves for capturing fine particles M of a desired size can be appropriately set.

In this embodiment, the drive control unit 421 can switch the ultrasonic element array 30 between a measurement mode and a standing wave generation mode. In such a configuration, by performing the measurement mode and the standing wave generation mode separately, it is possible to avoid mixing the ultrasonic waves for generating the standing wave SW and the ultrasonic waves for measuring the flow velocity. The configuration of the receiving circuit 413 can be simplified.

In this embodiment, the flow path 20 has a first flow path wall 221 and a second flow path wall 222 facing each other, and an ultrasonic element array 30 including a first ultrasonic element 33A and a second ultrasonic element 33B. is provided on the first flow path wall 221. With such a configuration, the flow velocity can be measured using the reflection of ultrasonic waves on the second flow path wall 222. Therefore, the use of acoustic force such as capturing the particles M and the measurement of the flow velocity can be performed by one ultrasonic element array 30.

[Second embodiment]
A fluid device 10 according to a second embodiment will be described with reference to FIG. 8.
The fluidic device 10 of the second embodiment is substantially the same as the first embodiment except that it includes a first ultrasonic element array 30A and a second ultrasonic element array 30B as an ultrasonic element group provided in the flow path 20. Equipped with a configuration. Hereinafter, the same reference numerals will be used for the same configurations as in the first embodiment, and the description thereof will be omitted or simplified.

The fluidic device 10 of the second embodiment includes a first ultrasonic element array 30A provided on a first channel wall 221 and a second ultrasonic element array 30B provided on a second channel wall 222. That is, the first ultrasonic element array 30A constitutes a part of the first channel wall 221, and the second ultrasonic element array 30B constitutes a part of the second channel wall 222, Each faces the fluid S within the channel body 22 .
In addition, below, the 1st ultrasonic element array 30A and the 2nd ultrasonic element array 30B may be simply described as ultrasonic element array 30A, 30B.

The configurations of the ultrasonic element arrays 30A and 30B are substantially the same as the ultrasonic element array 30 of the first embodiment, and each includes a plurality of ultrasonic elements 33 arranged in an array. Each ultrasonic element 33 in the ultrasonic element arrays 30A and 30B is drive-controlled by a drive control unit 421 via a circuit unit 41, as in the first embodiment.
However, the first ultrasonic element array 30A includes a first ultrasonic element 33A and a plurality of standing wave generating elements 33C as the plurality of ultrasonic elements 33. The second ultrasonic element array 30B includes, as the plurality of ultrasonic elements 33, a second ultrasonic element 33B and a plurality of standing wave generating elements 33C.

The arrangement of the first ultrasonic elements 33A (element column CH-A) in the first ultrasonic element array 30A and the arrangement of the second ultrasonic elements 33B (element column CH-B) in the second ultrasonic element array 30B are Although not particularly limited, it is assumed that the first ultrasonic element 33A (element row CH-A) is arranged on the upstream side of the flow path 20 than the second ultrasonic element 33B (element row CH-B). .
In the example shown in FIG. 8, the ultrasonic element 33 disposed at the upstream end of the first ultrasonic element array 30A is the first ultrasonic element 33A, and the ultrasonic element 33 disposed at the upstream end of the first ultrasonic element array 30A is The ultrasonic element 33 placed in the center is the second ultrasonic element 33B. Here, the inter-element distance d in the X direction between the first ultrasonic element 33A and the second ultrasonic element 33B is known.

The flow rate measurement method and control method in the fluid device 10 of the second embodiment are the same as those of the first embodiment. However, in the second embodiment, the ultrasonic propagation distance L' is expressed by the following equation (9), and cos θ in the above equation (5) is expressed by the following equation (10). Therefore, the flow velocity V is expressed by the following equation (11).

The fluid device 10 of the second embodiment described above has the same effects as the first embodiment. Further, in the fluidic device 10 of the second embodiment, since ultrasonic waves can be transmitted and received without reflection when measuring flow velocity, noise in the receiving circuit 413 can be reduced.

[Third embodiment]
A fluid device 10A of the third embodiment will be described with reference to FIG. 9.
The fluid device 10A of the third embodiment has substantially the same configuration as the first embodiment except that the circuit section 41A does not include the drive circuit 415 of the first embodiment. Hereinafter, the same reference numerals will be used for the same configurations as in the first embodiment, and the description thereof will be omitted or simplified.

In the third embodiment, the selection circuit 411A can connect each ultrasonic element 33 (element column CH) of the ultrasonic element array 30 to the transmitting circuit 412 or the receiving circuit 413.
When the drive control section 421 switches to the standing wave generation mode, the selection circuit 411A connects the standing wave generation element 33C (element column CH-C) and the transmission circuit 412 under the control of the drive control section 421. Then, the transmitting circuit 412 outputs a drive signal of a predetermined frequency f for forming a standing wave SW to the standing wave generating element 33C (element array CH-C).

In addition, in the third embodiment, in the standing wave generation mode, not only the standing wave generating element 33C (element row CH-C) but also the first ultrasonic element 33A (element row CH-A) and the second ultrasonic Element 33B (element column CH-B) may be connected to transmitter circuit 412. That is, not only the standing wave generating element 33C (element row CH-C), but also the first ultrasonic element 33A (element row CH-A) and the second ultrasonic element 33B (element row CH-B) Ultrasonic waves may be transmitted to generate the on-wave SW.

Further, in the third embodiment, in the measurement mode, any ultrasonic element 33 of the ultrasonic element array 30 may be selected as the first ultrasonic element 33A and the second ultrasonic element 33B.

[Modified example]
The present invention is not limited to the above-described embodiments, and the present invention includes modifications, improvements, and configurations obtained by appropriately combining the embodiments to the extent that the objects of the present invention can be achieved. be.

(Modification 1)
In the first and second embodiments described above, the drive control unit 421 switches the ultrasonic element array 30 between the measurement mode and the standing wave generation mode, but the flow velocity V of the fluid S is measured while the standing wave SW is being formed. You can.
For example, in the method for controlling the fluidic device 10 according to the modified example, steps S25 and S29 in the flowchart of FIG. 7 described in the first embodiment may be omitted. In this case, the drive circuit 415 starts driving the standing wave generating element 33C in step S23, and then continuously drives the standing wave generating element 33C. In step S26, while the drive circuit 415 is continuously driving the standing wave generating element 33C, the same flow velocity measurement method as in the first embodiment is performed.

In such a modification, the frequency of the ultrasonic waves transmitted from the first ultrasonic element 33A or the second ultrasonic element 33B (that is, the frequency of the ultrasonic waves for flow velocity measurement) is the same as that transmitted from the standing wave generating element 33C. It is preferable that the frequency is different from the frequency of the ultrasonic wave used for forming the standing wave (that is, the frequency of the ultrasonic wave for forming a standing wave). In this case, the receiving circuit 413 includes a reference signal circuit and a low-pass filter, and can extract a received signal derived from the ultrasonic wave for measuring the flow velocity by implementing a detection method such as orthogonal detection.
Note that the frequency of the ultrasonic waves used for measuring the flow velocity and the frequency of the ultrasonic waves used for forming the standing wave may be the same. In this case, the receiving circuit 413 may remove the received signal derived from the continuous wave for forming the standing wave with a filter, and extract the received signal derived from the burst wave for measuring the flow velocity.

(Modification 2)
In each of the above embodiments, the ultrasonic element arrays 30, 30A, and 30B may include a plurality of ultrasonic elements 33 arranged in an array. For example, the ultrasonic element arrays 30, 30A, and 30B are not limited to those that include a plurality of ultrasonic elements 33 arranged two-dimensionally in the XZ plane, but include a plurality of ultrasonic elements 33 arranged one-dimensionally in at least the X direction. It is sufficient as long as it includes.
Further, in the first embodiment, in the ultrasonic element array 30, the ultrasonic element 33 disposed at the upstream end is the first ultrasonic element 33A, and the ultrasonic element 33 disposed at the downstream end is the first ultrasonic element 33A. Although 33 is the second ultrasonic element 33B, the first ultrasonic element 33A and the second ultrasonic element 33B may each be any arbitrary ultrasonic element 33.
Further, in the first embodiment, a plurality of standing wave generating elements 33C are arranged between the first ultrasonic element 33A and the second ultrasonic element 33B, but at least one standing wave generating element 33C may be placed.

(Modification 3)
The ultrasonic element arrays 30, 30A, and 30B of each of the above embodiments may not include the standing wave generating element 33C. For example, among the ultrasonic element arrays 30, 30A, and 30B, the ultrasonic elements 33 other than the first ultrasonic element 33A and the second ultrasonic element 33B used for flow velocity measurement may be used for arbitrary purposes such as measuring the sound velocity in a fluid. May be used for.

(Modification 4)
In each of the above embodiments, the flow path 20 does not need to have the first flow path wall 221 and the second flow path wall 222 that face each other. For example, the flow path 20 may have a circular tube shape. In this case, it is preferable that the ultrasonic element arrays 30, 30A, and 30B include a plurality of ultrasonic elements 33 arranged one-dimensionally in the X direction.

(Modification 5)
In each of the above embodiments, the ultrasonic element group provided in the flow path 20 includes one ultrasonic element array 30, or a first ultrasonic element array 30A and a second ultrasonic element array 30B arranged opposite to each other. The following cases are described, but are not limited to these cases.
For example, the ultrasonic element group provided in the flow path 20 may include a plurality of ultrasonic element arrays 30 arranged on the first flow path wall 221 of the flow path 20. In this case, the first ultrasonic element 33A and the second ultrasonic element 33B only need to be included in any ultrasonic element array 30, and the ultrasonic element array 30 including the first ultrasonic element 33A and the The ultrasonic element array 30 including the two ultrasonic elements 33B may be different from each other.

(Modification 6)
In the ultrasonic element arrays 30, 30A, and 30B of each of the embodiments described above, the configuration of the ultrasonic elements 33 is not limited to that described above.
For example, the ultrasonic element 33 may have a configuration that vibrates a piezoelectric actuator, or may have a configuration that vibrates a diaphragm included in an electrostatic actuator. Such an ultrasonic element 33 can generate vibrations and transmit ultrasonic waves by applying a drive signal of a predetermined drive frequency.

[Summary of this disclosure]
A summary of the present disclosure is appended below.
(Additional note 1)
A fluidic device according to the present disclosure includes a flow path through which a fluid flows, an ultrasonic element group including a plurality of ultrasonic elements provided in the flow path and arranged in an array, and driving of the plurality of ultrasonic elements. and a flow velocity measuring section that measures the flow velocity of the fluid. The first ultrasonic element and the second ultrasonic element transmit and receive ultrasonic waves to and from each other via the fluid, and the flow rate measuring section is configured to transmit and receive ultrasonic waves from the first ultrasonic element to the second ultrasonic element. The flow velocity is measured based on a difference between a first ultrasonic propagation time and a second ultrasonic propagation time from the second ultrasonic element to the first ultrasonic element.
With such a configuration, the flow velocity of the fluid can be measured using any ultrasonic element included in the ultrasonic element group. As a result, it is possible to obtain fluid flow velocity information in the region where the acoustic force is generated, and it is possible to appropriately set the acoustic force on the particles in the fluid. Furthermore, the entire fluid device can be made smaller in size compared to the case where a conventional flow meter is provided in the fluid device.

(Additional note 2)
In the fluidic device according to Supplementary Note 1, the ultrasonic element group includes a standing wave generating element disposed between the first ultrasonic element and the second ultrasonic element, and the drive controller Preferably, the standing wave is generated in the fluid by transmitting ultrasonic waves of a predetermined frequency from the standing wave generating element to the fluid.
With such a configuration, particles in the fluid can be captured using the standing wave generated by the standing wave generating element. Furthermore, the amplitude of the ultrasonic waves for capturing particles of a desired size can be appropriately set.

(Appendix 3)
In the fluidic device according to Supplementary Note 2, the frequency of the ultrasound transmitted from the first ultrasound element or the second ultrasound element and the frequency of the ultrasound transmitted from the standing wave generation element are mutually different. Preferably, they are different.
With such a configuration, even if both the ultrasonic waves for forming a standing wave and the ultrasonic waves for measuring the flow velocity are received, the signal due to the ultrasonic waves for measuring the flow velocity can be suitably detected.

(Additional note 4)
In the fluid device according to Supplementary Note 2 or 3, the drive control section controls a measurement mode in which ultrasonic waves are transmitted and received between the first ultrasonic element and the second ultrasonic element, and a measurement mode in which the standing wave generating element It is preferable that it is possible to switch between the standing wave generation mode and the standing wave generation mode in which ultrasonic waves of the predetermined frequency are transmitted.
In such a configuration, by performing the measurement mode and the standing wave generation mode separately, signal detection using ultrasonic waves for flow velocity measurement can be easily performed.

(Appendix 5)
In the fluid device according to supplementary note 4, the drive control section causes the first ultrasonic element and the second ultrasonic element to generate the standing wave together with the standing wave generating element in the standing wave generation mode. The first ultrasonic element and the second ultrasonic element may be driven together with the standing wave generating element such that the standing wave generating element is driven.
In such a configuration, not only the standing wave generating element but also the first ultrasonic element and the second ultrasonic element can be used for generating standing waves, so it is possible to generate standing waves in a wider range. can.

(Appendix 6)
In the fluidic device according to any one of Supplementary Notes 1 to 5, the flow path has a first flow path wall and a second flow path wall that face each other, and the ultrasonic element group is arranged in the first flow path. The ultrasonic element array may be provided on a wall and include the first ultrasonic element and the second ultrasonic element.
With such a configuration, the ultrasonic propagation distance between the first ultrasonic element and the second ultrasonic element can be ensured, and the resolution of flow velocity measurement can be improved.

(Appendix 7)
In the fluidic device according to any one of Supplementary notes 1 to 6, the flow path has a first flow path wall and a second flow path wall that face each other, and the ultrasonic element group is arranged in the first flow path. a first ultrasonic element array provided on a wall and including the first ultrasonic element; a second ultrasonic element array provided on the second channel wall and including the second ultrasonic element; , may have.
With such a configuration, the S/N ratio when receiving ultrasonic waves for flow velocity measurement can be improved, and the accuracy of flow velocity measurement can be improved.

(Appendix 8)
A method for controlling a fluid device according to the present disclosure is a method for controlling a fluid device that measures the flow rate of a fluid, wherein the fluid device includes a flow path through which a fluid flows, and the fluid devices are provided in the flow path and arranged in an array. an ultrasonic element group including a plurality of ultrasonic elements, a drive control section that controls driving of the plurality of ultrasonic elements, and a flow velocity measurement section that measures the flow velocity of the fluid, the drive control section transmits and receives ultrasonic waves to and from each other via the fluid between any first ultrasonic element and second ultrasonic element that are arranged at different positions in the flow direction of the fluid among the group of ultrasonic elements. a first ultrasonic wave propagation time from the first ultrasonic element to the second ultrasonic element; and a second ultrasonic wave from the second ultrasonic element to the first ultrasonic element. and measuring the flow velocity based on a difference from a propagation time.
Depending on such a method, effects similar to those of the fluidic device described above can be obtained.

DESCRIPTION OF SYMBOLS 10, 10A... Fluid device, 20... Channel, 21... Inlet, 22... Channel main body, 221... First channel wall, 222... Second channel wall, 23... Concentration outlet, 24... Outlet, 25 ... Channel substrate, 30... Ultrasonic element array, 30A... First ultrasonic element array, 30B... Second ultrasonic element array, 31... Element substrate, 311... Substrate body, 311A... Opening, 312... Vibration membrane , 312A... Vibrating part, 32... Piezoelectric element, 321... First electrode, 321P... Electrode terminal, 322... Piezoelectric film, 323... Second electrode, 324... Common electrode wire, 324P... Electrode terminal, 33... Ultrasonic element, 33A... First ultrasonic element, 33B... Second ultrasonic element, 33C... Standing wave generating element, 40... Control section, 41, 41A... Circuit section, 411, 411A... Selection circuit, 412... Transmission circuit, 413... Receiving circuit, 414... TOF calculation circuit, 415... Drive circuit, 42... Processor, 421... Drive control section, 422... Flow velocity measuring section, 43... Memory, CH, CH-A, CH-B, CH-C... Element array , d... Distance between elements, L... Ultrasonic propagation distance, M... Fine particles, r... Channel width, S... Fluid, Sc... Concentrated liquid, Sr... Fluid, SW... Standing wave, V... Flow velocity.

Claims (8)

A channel through which fluid flows;
an ultrasonic element group provided in the flow path and including a plurality of ultrasonic elements arranged in an array;
a drive control unit that controls driving of the plurality of ultrasonic elements;
A flow rate measurement unit that measures the flow rate of the fluid,
The drive control unit is configured to perform ultrasonic control via the fluid between arbitrary first and second ultrasonic elements that are arranged at different positions in the fluid flow direction among the ultrasonic element group. send and receive sound waves to each other,
The flow rate measuring unit measures a first ultrasonic propagation time from the first ultrasonic element to the second ultrasonic element, and a second ultrasonic propagation time from the second ultrasonic element to the first ultrasonic element. A fluidic device that measures the flow rate based on a difference between the flow rate and the flow rate. The ultrasonic element group includes a standing wave generating element disposed between the first ultrasonic element and the second ultrasonic element,
The fluid device according to claim 1, wherein the drive control section generates a standing wave in the fluid by causing the standing wave generating element to transmit an ultrasonic wave of a predetermined frequency to the fluid. The fluid according to claim 2, wherein the frequency of the ultrasound transmitted from the first ultrasound element or the second ultrasound element and the frequency of the ultrasound transmitted from the standing wave generation element are different from each other. device. The drive control unit has a measurement mode in which ultrasonic waves are transmitted and received between the first ultrasonic element and the second ultrasonic element, and a measurement mode in which ultrasonic waves at the predetermined frequency are transmitted from the standing wave generating element. The fluidic device according to claim 2 or 3, wherein the fluidic device is switchable between a wave generation mode and a wave generation mode. The drive control unit controls the first ultrasonic wave so that in the standing wave generation mode, the first ultrasonic element and the second ultrasonic element together with the standing wave generating element generate the standing wave. The fluid device according to claim 4, wherein the element and the second ultrasonic element are driven together with the standing wave generating element. The flow path has a first flow path wall and a second flow path wall that face each other,
The fluid device according to claim 1, wherein the ultrasonic element group is an ultrasonic element array provided on the first channel wall and including the first ultrasonic element and the second ultrasonic element. The flow path has a first flow path wall and a second flow path wall that face each other,
The ultrasonic element group is
a first ultrasonic element array provided on the first channel wall and including the first ultrasonic element;
The fluidic device according to claim 1, further comprising a second ultrasonic element array provided on the second channel wall and including the second ultrasonic element. A method for controlling a fluid device that measures the flow rate of a fluid, the method comprising:
The fluidic device includes:
A channel through which fluid flows;
an ultrasonic element group provided in the flow path and including a plurality of ultrasonic elements arranged in an array;
a drive control unit that controls driving of the plurality of ultrasonic elements;
A flow rate measurement unit that measures the flow rate of the fluid,
The drive control unit controls ultrasonic transmission between any first ultrasonic element and second ultrasonic element, which are arranged at different positions in the fluid flow direction among the ultrasonic element group, via the fluid. transmitting and receiving sound waves to each other;
The flow velocity measuring unit measures a first ultrasonic propagation time from the first ultrasonic element to the second ultrasonic element and a second ultrasonic propagation time from the second ultrasonic element to the first ultrasonic element. and measuring the flow rate based on the difference between the flow rate and the flow rate.

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