Modular ultrasonic generating device and method of ultrasonically manipulating particles

Abstract

The application discloses a modular ultrasonic generating device and an ultrasonic manipulation particle method. The modular ultrasonic generating device is used for generating an acoustic field for manipulating the movement of a target object, and the device comprises an ultrasonic transducer and a modulation member. The ultrasonic transducer is used for generating a plane wave. The modulation member is arranged on a propagation path of the plane wave and located between the ultrasonic transducer and the target object. The modulation member can modulate the plane wave into a target acoustic field for manipulating the target object, so as to drive the target object to move along a set movement path. The modulation member comprises a plurality of unit modules capable of modulating corresponding sub-acoustic fields. The unit modules are spliced to make the sub-acoustic fields superimposed to form the target acoustic field. The modular ultrasonic generating device realizes the acoustic field for manipulation with diversified functions through the splicing of the plurality of unit modules. According to the manipulation requirements in different application scenarios, different modulation members can be dynamically and on-demand combined to modulate different manipulation particle modes with different functions.

Description

TECHNICAL FIELD

[0001] The present application relates to ultrasonic manipulation technology, and in particular to a modular ultrasonic generating device and an ultrasonic manipulation particle method. BACKGROUND

[0002] With the development of microfabrication technology, particle manipulation technology has a wide range of applications in chemical analysis, industrial production and manufacture, and biomedicine. At present, there are many methods for particle manipulation, such as using magnetic field, ultrasonic, water flow power, etc. to realize particle manipulation. Compared with other methods, ultrasonic driving technology has the characteristics of no need for labeling, no contact, strong penetration ability and good biocompatibility, which makes it have many advantages in biomedical applications.

[0003] Based on ultrasonic particle manipulation technology, the mechanical effect generated by the interaction between the acoustic field and the particles is used to drive the directional movement of the particles. Therefore, the trajectory of the particle movement under the action of the sound wave depends on the distribution mode of the acoustic field. The current acoustic field regulation means is mainly divided into two types: active and passive. The active type is mainly based on ultrasonic phased array, which can dynamically configure the excitation signal in real time, thereby realizing dynamic acoustic field regulation. However, this technology needs to build a complex driving circuit module, which is difficult to repair and maintain, and is limited by the size of the vibration element, has low regulation precision, and is difficult to realize miniaturization and integration. The passive type is mainly based on various artificial structures. Compared with the active type, this method can generate more complex acoustic field. Thanks to the development of micro-nano processing technology, the artificial structure is fine and low in cost. However, once the structure is set, the generated acoustic field is also relatively fixed and cannot be dynamically regulated in real time. For different needs, the structure needs to be redesigned, and the flexibility is poor. SUMMARY

[0004] The present application aims to at least solve one of the technical problems existing in the prior art. To this end, the present application proposes a modular ultrasonic generating device, which can dynamically and on-demand combine different modulation pieces according to the manipulation needs in different application scenarios, so as to modulate different functional target acoustic fields, and further realize diversified particle manipulation modes.

[0005] The present application also proposes an ultrasonic manipulation particle method with the above-mentioned modular ultrasonic generating device.

[0006] The modular ultrasonic generating device according to the first aspect of the embodiments of the present application comprises an ultrasonic transducer and a modulation member, the ultrasonic transducer is used to generate a plane wave; the modulation member is arranged on a propagation path of the plane wave and located between the ultrasonic transducer and the target object, and the modulation member can modulate the plane wave into a target sound field used for manipulating the target object to drive the target object to move along a set motion path; wherein the modulation member comprises a plurality of unit modules, each of the unit modules can modulate a corresponding sub-sound field, and each of the unit modules is spliced to superimpose each of the sub-sound fields to form the target sound field.

[0007] The modular ultrasonic generating device according to the embodiments of the present application has at least the following beneficial effects:

[0008] The modular ultrasonic generating device in the first aspect of the embodiments of the present application can dynamically and on-demand combine a plurality of unit modules to form different modulation members according to the manipulation requirements in different application scenarios, so as to modulate target sound fields with different functions, and then realize diversified manipulation modes. The modular ultrasonic generating device can be pre-assembled with a module library having commonly used unit modules, and when a new target sound field needs to be reconstructed, the unit modules in the original modulation member are replaced and rearranged, so that the device has high flexibility. In addition, one unit module can be applied to the assembly of multiple modulation members, so that the reuse rate is high and the comprehensive cost is low.

[0009] According to some embodiments of the present application, each of the unit modules at least modulates one of the following sub-sound fields:

[0010] a first sub-sound field used for driving the target object to move along a straight line;

[0011] a second sub-sound field used for driving the target object to change the moving direction.

[0012] According to some embodiments of the present application, the modulation member further comprises a base, one side of the base is connected with the ultrasonic transducer, and the other side is provided with a groove, and each of the unit modules is arranged in the groove.

[0013] According to some embodiments of the present application, the modular ultrasonic generating device further comprises a transducer moving mechanism and a loading mechanism, the loading mechanism is used for placing the target object, and the transducer moving mechanism is used for driving the ultrasonic transducer to move close to or away from the loading mechanism, so that the target object is located in the target sound field.

[0014] According to some embodiments of the present application, the loading mechanism comprises a container, the container contains a sound propagation medium, and the target object floats in the container under the action of the buoyancy of the sound propagation medium.

[0015] According to some embodiments of the present application, the modular ultrasonic generating device is provided with a plurality of ultrasonic transducers, each of which corresponds to one of the unit modules.

[0016] According to some embodiments of the present application, the unit modules are provided with a plurality of microstructures, each of which has a different height or a different cross-sectional area.

[0017] According to some embodiments of the present application, the arrangement and / or number of the microstructures on each of the unit modules are different.

[0018] According to some embodiments of the present application, the unit modules are provided with a plurality of adjustment parts, each of which is made of a combination of at least two materials capable of modulating sound field, and each of the adjustment parts has a different material ratio.

[0019] The method for manipulating micro-particles by ultrasonic waves according to the second aspect of the embodiments of the present application comprises the following steps:

[0020] determining a set motion path of a target object;

[0021] dividing the set motion path into a plurality of sub-paths;

[0022] selecting corresponding unit modules according to the sub-paths;

[0023] splicing the unit modules to form a modulation member;

[0024] forming a target sound field by the modulation member to drive the target object to move along the set motion path.

[0025] According to some embodiments of the present application, the step of dividing the set motion path into a plurality of sub-paths comprises:

[0026] determining the number of unit modules according to the manipulation precision, the size of the set motion path, or the complexity of the set motion path;

[0027] dividing the sub-paths according to the number of unit modules.

[0028] Additional aspects and advantages of the present application will be given, partially in the following description, partially become obvious from the following description, or be understood by practice of the present application. BRIEF DESCRIPTION OF DRAWINGS

[0029] The present application will be further described below in conjunction with the drawings and embodiments, in which:

[0030] Figure 1 a structural schematic diagram of the modular ultrasonic generating device according to an embodiment of the present application;

[0031] Figure 2 A schematic diagram of a modulating member formed by splicing unit modules of an embodiment of the present application;

[0032] Figure 3 A schematic diagram of an embodiment of a modulating member of the present application;

[0033] Figure 4 A set of test data graphs of a modular ultrasound generating device of an embodiment of the present application;

[0034] Figure 5 Another set of test data graphs of a modular ultrasound generating device of an embodiment of the present application;

[0035] Figure 6 A flowchart of a method of ultrasonically manipulating particles of an embodiment of the present application;

[0036] Figure 7 Another flowchart of a method of ultrasonically manipulating particles of an embodiment of the present application.

[0037] Reference Signs:

[0038] Ultrasound transducer 100; modulating member 200; unit module 210; straight unit module 211; curved unit module 212; target object 300; container 400; acoustic propagation medium 410. DETAILED DESCRIPTION

[0039] Embodiments of the present application are described in detail below with reference to the attached drawing figures, wherein the same or like reference numerals and characters throughout the figures denote the same or like components or elements having the same or similar functions. The embodiments described below are merely exemplary for the purpose of explaining the present application and are not to be construed as limiting the present application.

[0040] In the description of the present application, it is to be understood that the relative or positional description such as upper, lower, front, back, left, right, etc. is based on the relative or positional relationship shown in the drawings, and is only for the purpose of facilitating the description of the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the device or element indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application.

[0041] In the description of the present application, if the meaning of several is more than one, the meaning of multiple is more than two, greater than, less than, more than, etc. is understood as not including the number, above, below, etc. is understood as including the number. If it is described as first, second, etc., it is only for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features or implicitly indicating the order of indicated technical features.

[0042] In the description of the present application, the words such as arrangement, installation, connection and the like should be understood in a broad sense, and the specific meanings of the words in the present application can be determined by the person skilled in the art in combination with the specific content of the technical solutions.

[0043] In the description of the present application, the description of the terms "one embodiment", "some embodiments", "exemplary embodiment", "example", "specific example" or "some examples" means that the specific features, structures, materials or characteristics described in combination with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the exemplary description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0044] Particles will be subjected to acoustic radiation force under the action of an ultrasonic sound field, thereby driving the particles to move. The acoustic radiation force refers to the force of energy and momentum generated by the sound wave in the medium on the object. When the sound wave passes through the substance, it will cause the vibration and deformation of the medium, and correspondingly make the particles produce momentum, and then be subjected to a radiation force. This radiation force is also called interaction force, which is usually a non-contact force related to the distance between the substance. Therefore, the acoustic driving microparticle manipulation can realize non-contact and directional manipulation.

[0045] Based on the above principle, the first aspect embodiment of the present application proposes a modular ultrasonic generating device, as shown in Figure 1 The modular ultrasonic generating device includes an ultrasonic transducer 100 and a modulation piece 200, and can be used to manipulate the target object 300 to move. It should be explained that the target object 300 can be a macroscopic object, or a microscopic particle, cell or the like. By changing the ultrasonic frequency, ultrasonic energy, ultrasonic pulse length, ultrasonic pulse repetition frequency and other parameters of the ultrasonic transducer 100, different sizes of objects can be driven to move.

[0046] Specifically, the ultrasonic transducer 100 can be a piezoelectric ultrasonic transducer 100, a capacitive micromechanical ultrasonic transducer 100, a piezoelectric micromechanical ultrasonic transducer 100 or other types of ultrasonic transducers 100. The ultrasonic transducer 100 can emit a plane wave, and the wave front phase distribution of the plane wave is relatively uniform, which is conducive to the modulation of the modulation piece 200. The modulation piece 200 is arranged on the propagation path of the plane wave. In some embodiments, as shown in Figure 1 The modulation piece 200 is embedded in the ultrasonic transducer 100; in other embodiments, the modulation piece 200 can be arranged separately from the ultrasonic transducer 100.

[0047] It can be understood that the modulation piece 200 is located between the ultrasonic transducer 100 and the target object 300, and the plane wave emitted by the ultrasonic transducer 100 reaches the plane where the target object 300 is located after passing through the modulation piece 200. Due to the interaction between the structure of the modulation piece 200 and the sound wave, the phase of the wave front of the sound wave changes, thereby forming a target sound field for manipulating the movement of the target object 300. The operating sound field produces a specific distribution pattern on the plane where the target object 300 is located, so that the target object 300 can move along the set movement path.

[0048] It can be understood that the shape of the modulation piece 200 includes but is not limited to a circle, a square, etc., and the material for manufacturing the modulation piece 200 includes but is not limited to resin, silicone, rubber, etc., and the manufacturing process includes but is not limited to laser etching, 3D printing, injection molding, etc. In the prior art, a controllable sound field is generated by an ultrasonic phased array, which requires the construction of a complex drive circuit module, making repair and maintenance difficult. Moreover, it is limited by the size of the vibration element, has low control precision, and is difficult to achieve miniaturization and integration. However, the modular ultrasonic generating device in the embodiment of the present application uses the modulation piece 200 to construct a target sound field. Since the manufacturing precision of the modulation piece 200 is high, the modular ultrasonic generating device in the embodiment of the present application can achieve fine trajectory manipulation of particles with small sizes. Moreover, the material for manufacturing the modulation piece 200 is inexpensive, and the manufacturing process is simple, thereby reducing the use cost of the device.

[0049] It can be understood that the modular ultrasonic generating device further includes an ultrasonic excitation mechanism (not shown in the figure), which includes an ultrasonic signal generator and a signal amplifier. When the modular ultrasonic generating device is working, the ultrasonic signal generator generates a continuous electric excitation signal, which is transmitted to the ultrasonic transducer 100 after being amplified by the signal amplifier, and converts the electric signal into a mechanical vibration signal to generate a sound wave. The modular ultrasonic generating device further includes a cooling mechanism (not shown in the figure), which is attached to the ultrasonic transducer 100 and can enhance the heat dissipation performance of the ultrasonic transducer 100 to avoid overheating and resulting in failure of the ultrasonic transducer 100 when working for a long time.

[0050] In the prior art, the modulation piece 200 is usually integrally formed by processes such as 3D printing. The structure of such a modulation piece 200 is fixed, and one modulation piece 200 can only form one target sound field. If the modulation piece 200 is not replaced, the target object 300 can only move along a fixed path. If the use requirements change and the set movement path of the target object 300 changes, adaptive adjustment of the sound field is required. Therefore, the modulation piece 200 needs to be re-made, and the debugging work of ultrasonic manipulation can be carried out only after the modulation piece 200 is made, which has a long time span.

[0051] When multiple paths need to be manipulated on the target object 300, multiple modulators 200 need to be prepared for replacement. On the one hand, it is impossible to dynamically adjust the set movement path of the target object 300 according to the requirements; the corresponding modulator 200 can only be selected from a few specific set movement paths, resulting in poor flexibility. On the other hand, when there are many types of movement paths for the target object 300, the same number of modulators 200 need to be prepared, each corresponding to one of the movement paths. This requires manufacturing a large number of modulators 200 for use, resulting in high operating costs.

[0052] To solve the above problems, such as Figures 2 to 5 As shown, the modulator 200 in the first aspect embodiment of this application includes a plurality of unit modules 210, each unit module 210 being capable of modulating a plane wave into a corresponding sub-sound field. The unit modules 210 include linear unit modules 211, curved unit modules 212, composite unit modules, etc. For example: Reference Figure 5 As shown, the linear unit module 211 can modulate a first sub-sound field. When the target object 300 is located in the first sub-sound field, under the action of sound radiation force, the target object 300 can move in a straight line along a set direction; refer to Figure 4 As shown, the curve unit module 212 can modulate a second sub-sound field. When the target object 300 is in the second sub-sound field, it can change its direction of movement under the influence of sound radiation force. Alternatively, the composite unit module can modulate a first sub-sound field and a second sub-sound field so that when the target object 300 is in the sound field of the composite unit module, it can move in a straight line and a curve in sequence.

[0053] The curve unit module 212 can be further divided into a steering unit module, a reverse unit module, etc. For example, when the target object 300 is in the sub-sound field of the steering unit module, the target object 300 moves along a quarter-circle arc path or an L-shaped straight bend path, and the target object 300 changes from moving along the first direction to moving along a second direction perpendicular to the first direction; when the target object 300 is in the sound field of the reverse unit module, the target object 300 moves along a semi-circle arc path, and the target object 300 changes from moving along the first direction to moving in the opposite direction of the first direction. According to the design requirements of the steering unit module 210, the movement path of the target object 300 in the second sub-sound field can also be other forms of arc segments, straight bend segments, etc.

[0054] It is understandable that the movement and steering of the target object 300 can be accomplished within the sound field of a single curve unit module 212, or it can be achieved through a combination of the sound fields of multiple curve unit modules 212, for example... Figure 3In the embodiment shown, the target object 300 needs to move along the perimeter of the square in a single or cyclic manner. To this end, a plurality of unit modules 210 are arranged in sequence along the movement path of the target object 300 to form a square ring pattern as shown in Figure 3 It should be noted that in the embodiment shown in Figure 3 In the embodiment shown in

[0055] The second and fourth unit modules on the same side of the square path are connected by the third unit module, which is a straight line unit module 211, capable of driving the target object 300 to move from the second unit module to the fourth unit module. It can be understood that the target object 300 needs to change direction four times for each cycle, so the first, second and fourth unit modules are arranged at the four corners of the square path to form a second sub-acoustic field capable of driving the target object 300 to move and change direction. The third unit module is arranged on the four sides of the square path to form a first sub-acoustic field capable of driving the target object 300 to move in a straight line.

[0056] It should be noted that during the splicing of each unit module 210, there are areas that do not involve controlling the target object 300, for example Figure 3 The nine square areas in the middle of the ring-shaped modulation member 200, in these areas, a block of sound-transparent material can be provided which is the same size as the unit module 210 to abut against the surrounding unit modules 210. Alternatively, these areas can be left empty.

[0057] Each unit module 210 is spliced together to form the modulation member 200, so that when the plane wave emitted by the ultrasonic transducer 100 passes through the modulation of each unit module 210 on the modulation member 200, a target acoustic field is formed. As shown in Figure 4 In the embodiment shown, the feasibility of the modulation member 200 formed by splicing for modulating the acoustic field has been verified by experiments. It should be noted that Figure 4 (a) is a target trajectory diagram, Figure 4 (b) is a phase distribution diagram on the modulation member 200, Figure 4 (c) is a schematic diagram of the target acoustic field, Figure 4(d) is a computer simulation of the moving track of the target object 300, it can be seen that the simulated moving track is basically consistent with the set track.

[0058] Figure 5 Another embodiment is also proposed in the present application, and it is explained that, Figure 5 (a) is a target track diagram, Figure 5 (b) is a phase distribution diagram on the modulation member 200, Figure 5 (c) is a diagram of the target sound field, Figure 5 (d) is a computer simulation of the moving track of the target object 300.

[0059] In this embodiment, as shown in Figure 5 (a), it is required to control multiple target objects 300 to move from the left to the right at the same time, according to this set motion path, the unit modules 210 are reselected and a new modulation member 200 is composed as shown in Figure 5 (b). Since it is required to control 3 target objects 300 to move linearly in this application scenario, three rows of linear unit module groups are provided, each row of linear unit module groups includes 5 linear unit modules 211, and each linear unit module 211 is arranged in the same direction. The distribution mode of the sound field of the modulation member 200 is shown in Figure 5 (c), and the simulated moving track of the target object 300 under the action of the sound field is shown in Figure 5 (d).

[0060] Therefore, the modular ultrasonic generating device in the first aspect embodiment of the present application realizes diversified control modes through the splicing of multiple unit modules 210. The modular ultrasonic generating device can dynamically and on-demand combine different modulation members 200 according to the control requirements in different application scenarios, so as to modulate target sound fields with different functions. The modular ultrasonic generating device can be pre-assembled with a module library having common unit modules 210, and when a new target sound field needs to be reconstructed, the unit modules 210 in the original modulation member 200 are replaced and rearranged, so that the device has high flexibility. Moreover, one unit module 210 can be applied to the assembly of multiple modulation members 200, so that the reuse rate is high and the comprehensive cost is low.

[0061] The module library configured by the modular ultrasonic generating device is provided with multiple unit modules 210, and appropriate unit modules 210 are selected from the module library for splicing when a sound field model needs to be constructed. It can be understood that the same unit modules 210 can be provided with only one or multiple, and the unit modules 210 can be square, rectangular or other shapes that are easy to splice. For example, as shown in Figure 1In the illustrated embodiment, each straight unit module group includes five 4mm x 4mm square straight unit modules 211, and the same function can also be achieved by a 12mm x 4mm rectangular straight unit module 211.

[0062] Taking a straight and bent unit module with a commonly used moving path of L shape as an example, the design principle of each unit module is as follows:

[0063] Suppose the sound field at z = 0 (i.e. the output sound field of the ultrasonic transducer 100) is p = (x, y, 0), then the sound field p = (x, y, z) at z > 0 can be calculated by the angular spectrum method. The angular spectrum representation in a constant z plane is the Fourier transform of the sound field in this plane:

[0064]

[0065] According to the above formula, the angular spectrum P(k x ,k y ,0) at z = 0 can be obtained. The angular spectrum of any plane can be calculated by multiplying the angular spectrum by the propagation function:

[0066] P(k x ,k y ,z) = P(k x ,k y ,0)H(k x ,k y ,z) (2)

[0067]

[0068] where k = ω / c is the wave number in the medium, and ω and c are the angular frequency and the sound speed in the liquid medium, respectively.

[0069] The sound pressure field in the plane z can be substituted into the angular spectrum P(k x ,k y ,z) and calculated by the inverse Fourier transform, and the sound pressure field representation in any plane is:

[0070]

[0071] Suppose the modulating member 200 is located in the initial plane z = 0. First, the modulating member 200 is initialized to a random phase distribution The phase change introduced by the modulating member 200 is through transmission. In the case of assuming that the incident source is uniformly distributed, the amplitude distribution is a constant amplitude, denoted as A0. At this time, the sound pressure field on the upper surface of the modulating member 200 is The sound pressure field p0 propagates forward, i.e. after Fourier transform, multiplied by the corresponding angular spectrum propagation operator, and then inverse Fourier transform can get the sound pressure of the imaging plane, which is expressed as At this time, the phase and amplitude of the sound field of the imaging plane are modulated at the same time, the phase at the target pattern is directly replaced by the ideal phase, and the amplitude at the target pattern is changed to the target amplitude. The changed phase is denoted as The changed amplitude is denoted as A T Then the sound field of the imaging plane becomes The sound pressure field p1 propagates backward, i.e. after Fourier transform, multiplied by the corresponding inverse angular spectrum propagation operator, and then inverse Fourier transform can get the sound pressure of the initial plane The optimized result is assigned to and A2 is replaced by A0. After that, the process of forward propagation, phase amplitude modulation, and backward propagation is repeated to finally get the phase distribution of the optimized modulation piece 200

[0072] Taking the thickness-modulated modulation piece 200 as an example, there is the following relationship between the phase distribution and the thickness distribution:

[0073]

[0074] T = T0- ΔT(x, y)

[0075] Where T0 represents the initial thickness defined by the user, ΔT represents the relative thickness change, k m and k h represent the wave vectors of the medium and the material for making the modulation piece 200, respectively. According to the finally obtained thickness distribution T, the holographic structure of the required unit module can be prepared by applying 3D printing or laser etching, etc.

[0076] The simulation calculation process of the particle motion trajectory in the spliced holographic sound field is as follows:

[0077] To verify whether the particle can walk along the preset trajectory, the first step is to calculate the acoustic radiation force on the particle:

[0078] First, assume that the incident sound field is known at z = 0, and the complex pressure amplitude is a known function:

[0079] p i | z＝0 = p i (x, y, 0) (1)

[0080] Next, through Fourier transform, the angular spectrum of the incident complex sound field is specifically expressed as:

[0081]

[0082] The angular spectrum of the incident complex sound field multiplied by the angular spectrum propagation operator and inverse Fourier transform can obtain the complex sound field in the full space of any two-dimensional plane parallel to the incident plane:

[0083]

[0084] In the formula, z is the propagation distance. Since the plane wave is axisymmetric, the incident sound field can be rewritten as:

[0085]

[0086] In the formula, j n (g) is the spherical Bessel function of the nth order, is the spherical harmonic function, and the superscript asterisk “*” represents the conjugate of the complex number. For the above incident sound field, the scattering sound field of the particle can be expressed as:

[0087]

[0088] In the formula, is the first type of spherical Hankel function of the nth order, c n is the scattering coefficient of the particle. At this time, the total sound field in the full space is:

[0089]

[0090] Wherein,

[0091] The sound radiation force acting on the particle can be expressed as:

[0092]

[0093] In the formula, dS=ndS is the unit area element normal outward, n is the normal direction of the Mie particle surface outward, S is the surface area of the object, and <∏> is the time-averaged momentum flux density tensor, and can be expressed as:

[0094]

[0095] In the formula, ρ and c are the density and sound speed of the surrounding fluid, respectively, and p and v r are the first-order sound pressure total sound pressure field and total velocity field, respectively, <g>Time average of a physical quantity over a unit period.

[0096] Substitute the total sound field into the first-order velocity field equation The first-order velocity field is obtained as

[0097]

[0098] Substitute the total sound pressure field and the velocity field into equations (7) and (8), and substitute the spherical Bessel function j n (g) and the first kind spherical Hankel function Make far field approximation, and obtain the normalized sound radiation force components in x, y and z directions:

[0099]

[0100]

[0101]

[0102] where,

[0103] Second step, obtain the particle trajectory in the sound field according to the sound radiation force and other external forces.

[0104] The particle is mainly affected by the sound radiation force and the fluid drag force. According to Newton's second law, the motion equation of the Mie particle in the static fluid is:

[0105]

[0106] In the formula, m and v are the mass and motion velocity of the Mie particle respectively, F rad is the sound radiation force, and F drag is the fluid drag force caused by the flow. Since the size of the Mie particle is large, the influence of the acoustic streaming effect on the motion of the Mie particle is negligible. Therefore, the fluid drag force can be expressed as:

[0107] F drag = -6πμav (14)

[0108] In the formula, μ is the dynamic viscosity coefficient of the fluid, and a is the radius of the Mie particle.

[0109] Under the condition of given initial position and velocity of the Mie particle, the motion trajectory of the particle is calculated by using piecewise approximation, that is, in a small time interval, the particle is considered to do uniform variable speed linear motion. The sum of all time intervals is the total time of the particle motion, and the sum of the particle motion displacement in the time interval is the total motion trajectory of the particle.

[0110] Based on the above steps, the unit module 210 capable of modulating the target sub-acoustic field can be designed, and simulation verification can be performed.

[0111] In some embodiments, the unit modules 210 are spliced with each other to form the modulation piece 200. Alternatively, the modulation piece 200 further includes a base, which is generally made of the same material as the unit module 210. The modulation piece 200 can be connected to the base and spliced on the base to form the modulation piece 200. It can be understood that the connection between the modulation piece 200 and the base can be plug-in, clamping, gluing, etc. or the modulation piece 200 can be placed on the base without setting a connection structure.

[0112] For example, in the embodiment as shown in Figure 4 The ultrasonic transducer 100, the modulation piece 200, and the target object 300 are arranged in a direction from bottom to top. The lower side of the base (not shown in the figure) is connected with the ultrasonic transducer 100, and the upper side is provided with a groove. Each unit module 210 is arranged in the groove. Further, the size of the groove can be just equal to the outer diameter size of the plurality of unit modules 210 after splicing. For example, in the embodiment as shown in Figure 1 The size of the groove can be set to 40mm×40mm. When each unit module 210 is installed in the groove, the adjacent unit modules 210 abut with each other, and the unit module 210 at the edge abuts with the groove wall, thereby limiting the displacement of each unit module 210 in the horizontal direction.

[0113] In some embodiments, the modular ultrasonic generating device further includes a transducer moving mechanism and a loading mechanism. The loading mechanism is used to place the target object 300. It can be understood that the loading mechanism can be a platform capable of transmitting sound waves. The target object 300 is supported by the platform and can be parked on the platform. The target object 300 can be moved on the surface of the platform under the action of the acoustic radiation force. The loading mechanism can also be loaded with a sound propagation medium 410 such as gas or liquid. The target object 300 is located in the sound propagation medium 410 and is parked in the sound propagation medium 410 under the action of the buoyancy of the sound propagation medium 410. The target object 300 can be moved in the sound propagation medium 410 under the action of the acoustic radiation force. The transducer moving mechanism is connected with the ultrasonic transducer 100 to drive the ultrasonic transducer 100 to move in the direction close to or away from the loading mechanism. Thus, the transducer moving mechanism can adjust the position of the ultrasonic transducer 100 according to the change of the intensity of the acoustic field, the distance between the target object 300 and the ultrasonic transducer 100, and other factors, so that the target object 300 is located in the target acoustic field.

[0114] Further, referring to Figure 1 As shown, the loading mechanism includes a container 400, in which a sound propagation medium 410 is contained. The sound propagation medium 410 can be a liquid or a gas. The target object 300 floats in the container 400 due to the buoyancy of the sound propagation medium 410. It can be understood that the density of the target object 300 can be the same as that of the sound propagation medium 410, so that the target object 300 floats in the sound propagation medium 410. The density of the target object 300 can also be less than that of the sound propagation medium 410, so that the target object 300 floats on the upper surface of the sound propagation medium 410. The gravity of the target object 300 is counteracted by the buoyancy of the sound propagation medium 410, so that the target object 300 is in a balanced state in the vertical direction. In the embodiment as shown, the sound propagation medium 410 is a liquid, and the target object 300 floats on the liquid surface. The transducer moving mechanism can move the ultrasonic transducer 100 to a corresponding position, so that the target sound field generated by the modulation member 200 acts on the liquid surface, thereby facilitating the manipulation of the target object 300. Figure 2 In the embodiment as shown, the sound propagation medium 410 is a liquid, and the target object 300 floats on the liquid surface. The transducer moving mechanism can move the ultrasonic transducer 100 to a corresponding position, so that the target sound field generated by the modulation member 200 acts on the liquid surface, thereby facilitating the manipulation of the target object 300.

[0115] It can be understood that the ultrasonic transducer 100 and the modulation member 200 can be arranged above the container 400 and emit sound waves from top to bottom. Alternatively, the ultrasonic transducer 100 and the modulation member 200 can be arranged below the container 400, and the sound waves pass through the container 400 and are propagated to the plane where the target object 300 is located by the sound propagation medium 410.

[0116] In some embodiments, when the size of each unit module 210 of the modulation member 200 is small, and the number of unit modules 210 is small, the volume of the entire modulation member 200 is not large, and the sound waves generated by one ultrasonic transducer 100 can cover all the unit modules 210. In this case, one ultrasonic transducer 100 can be used to generate the required target sound field. In other embodiments, when the size of the unit module 210 of the modulation member 200 is large, or the number of unit modules 210 is large, multiple ultrasonic transducers 100 can be used to generate plane waves. Further, the number of ultrasonic transducers 100 is consistent with the number of unit modules 210, so that each ultrasonic transducer 100 corresponds to one unit module 210. Thus, multiple ultrasonic transducers 100 can work together, which can work at the same frequency or multiple frequencies.

[0117] The artificial microstructure is arranged on the unit module 210. Different microstructures can achieve different phase delays. It can be understood that the micro-pillars can be prismatic, cylindrical or other shaped pillars. In some embodiments, as shown in FIG. 2, the unit module 210 is provided with a plurality of micro-pillars 220 arranged in a grid pattern. The micro-pillars 220 can be prismatic, cylindrical or other shaped pillars. The micro-pillars 220 can be arranged in a grid pattern, or can be arranged in other patterns. Figure 2 As shown, the unit module 210 is provided with a plurality of micro columns, each micro column has the same cross-sectional area and different heights, and the micro columns with different heights can cause different phase delays. Through the ordered combination of a plurality of micro structures, different delays occur when the sound wave passes through the unit module 210, forming a new phase distribution and propagating forward. In other embodiments, each micro column has the same height and different cross-sectional areas, which can also produce different delay effects.

[0118] It should be explained that, Figure 6 The schematic diagram of the micro structure on the unit module 210 is shown, and the number and arrangement of the micro columns on the unit module 210 do not represent the actual number and arrangement of the micro columns on the unit module 210.

[0119] In other embodiments, the unit module 210 is provided with a plurality of adjustment parts, each adjustment part can be combined by at least two materials capable of modulating the sound field, and the proportion of the materials in each adjustment part is different, thereby being able to produce different delay effects on the sound wave.

[0120] Based on the modular ultrasonic generating device mentioned in any of the above embodiments, with reference to Figure 3 As shown, the second aspect of the present application also proposes an ultrasonic control particle method, which comprises the following steps:

[0121] S100, determining a set motion path of a target object;

[0122] S200, dividing the set motion path into a plurality of sub-paths;

[0123] In the process of dividing the sub-paths, the curve segments and the straight line segments are generally divided into different sub-paths, so as to be respectively realized by the curve unit module 212 and the straight line unit module 211.

[0124] S300, selecting a corresponding unit module according to the sub-path;

[0125] As Figure 7 As shown, different types of unit modules 210 have significant differences in appearance, and different types of unit modules 210 can be distinguished when selecting the unit module 210.

[0126] S400, splicing the unit modules to form a modulation piece;

[0127] S500, forming a target sound field by the modulation piece to drive the target object to move along the set motion path.

[0128] Specifically, the ultrasonic frequency, ultrasonic energy and other parameters can be adjusted by the ultrasonic excitation mechanism, so that the ultrasonic transducer 100 generates appropriate plane waves. The distance between the ultrasonic transducer 100 and the target object 300 can also be adjusted in combination with the transducer moving mechanism, so that the target object 300 is in the target sound field.

[0129] Further, referring to FIG. 1, the step S200 can be further refined as follows: ​

[0130] S210, determining the number of unit modules according to the control accuracy, the size of the set motion path or the complexity of the set motion path;

[0131] For example, when the set motion path is a relatively long straight path, multiple straight unit modules 211 can be selected to splice to modulate the corresponding target sound field. When the set motion path is a circular arc with a large radius, multiple curved unit modules 212 can be selected to splice to modulate the corresponding target sound field. Alternatively, when the design path is S-shaped, a combination of multiple curved unit modules 212 and straight unit modules 211 is required to modulate the corresponding target sound field. Alternatively, when the control accuracy requirement is high, the size of each unit module 210 can be reduced and the number of unit modules 210 can be increased to achieve more accurate control.

[0132] S220, dividing the sub-paths according to the number of unit modules.

[0133] It can be understood that the number of sub-paths should be consistent with the number of unit modules 210, and each sub-path corresponds to a unit module 210 that can realize the corresponding sound field.

[0134] Based on the above ultrasonic control particle method, the flexibility of the modular ultrasonic generating device in the first aspect of the present application is fully embodied, which can dynamically adjust the set motion path according to the demand, and can realize the reconstruction of the sound field by replacing the unit module 210 or changing the arrangement order of the unit module 210, which is relatively convenient and fast.

[0135] The embodiments of the present application are described in detail above in combination with the drawings, but the present application is not limited to the above embodiments, and various changes can be made within the scope of knowledge possessed by those skilled in the art without departing from the purpose of the present application. In addition, the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.​< / g>

Claims

1. A method for ultrasonically manipulating microparticles, characterized in that, An application in a modular ultrasound generating device, the modular ultrasound generating device being used to generate a sound field for manipulating the movement of a target object, the modular ultrasound generating device comprising: An ultrasonic transducer for generating plane waves; A modulator is disposed on the propagation path of the plane wave and located between the ultrasonic transducer and the target object. The modulator can modulate the plane wave into a target sound field for manipulating the target object, thereby driving the target object to move along a set motion path. The modulator includes multiple unit modules, each of which can modulate a corresponding sub-sound field. The unit modules are spliced ​​together to superimpose the sub-sound fields to form the target sound field. The ultrasonic manipulation method for microparticles includes: Determine the set motion path of the target object; The defined motion path is divided into multiple sub-paths; Select the corresponding unit module according to the sub-path; The unit modules are assembled to form a modulation element; The modulator forms a target sound field to drive the target object to move along the set motion path.

2. The ultrasonic manipulation method for microparticles according to claim 1, characterized in that, Each of the aforementioned unit modules modulates at least one of the following sub-sound fields: A first sub-sound field used to drive the target object to move in a straight line; The second sub-sound field is used to drive the target object to change its direction of movement.

3. The ultrasonic manipulation method for microparticles according to claim 1, characterized in that, The modulator also includes a base, one side of which is connected to the ultrasonic transducer, and the other side has a groove in which each of the unit modules is disposed.

4. The ultrasonic manipulation method for microparticles according to claim 1, characterized in that, The modular ultrasonic generating device further includes a transducer moving mechanism and a loading mechanism. The loading mechanism is used to place the target object, and the transducer moving mechanism is used to drive the ultrasonic transducer to move closer to or further away from the loading mechanism so that the target object is located in the target sound field.

5. The ultrasonic manipulation method for microparticles according to claim 4, characterized in that, The loading mechanism includes a container containing a sound propagation medium, and the target object floats in the container due to the buoyancy of the sound propagation medium.

6. The ultrasonic manipulation method for microparticles according to claim 1, characterized in that, The modular ultrasonic generating device is provided with multiple ultrasonic transducers, and each ultrasonic transducer corresponds to one of the unit modules.

7. The ultrasonic manipulation method for microparticles according to claim 1, characterized in that, The unit module is provided with multiple microstructures, each with a different height or a different cross-sectional area.

8. The ultrasonic manipulation method for microparticles according to claim 7, characterized in that, The arrangement and / or number of microstructures on each of the unit modules are different.

9. The ultrasonic manipulation method for microparticles according to claim 1, characterized in that, The unit module is provided with multiple adjustment sections, each of which is made of at least two materials capable of modulating the sound field, and the proportion of materials in each adjustment section is different.

10. The ultrasonic manipulation method for microparticles according to claim 1, characterized in that, The step of dividing the set motion path into multiple sub-paths includes: The number of unit modules is determined based on the control precision, the size of the set motion path, or the complexity of the set motion path. The sub-paths are divided according to the number of unit modules.

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