An acoustic metasurface device for localized, multidimensional manipulation of millimeter-scale particles

Abstract

This invention discloses an acoustic metasurface for localized, non-contact, multi-dimensional manipulation of millimeter-scale particles. The levitation height and rotation of individual millimeter-scale particles are controlled by adjusting the background sound pressure amplitude and initial phase. The designed acoustic metasurface consists of N×N units arranged in a planar pattern according to a specific rule. The metasurface units must satisfy the condition that, under the condition of incident sound waves applied from both sides, the phase delay of the resulting scattered sound field is 2π / 2 within one period. n There are discrete gradient distributions (n ​​is an integer greater than or equal to 1). In addition, the configuration of the unit must meet the requirements of biisotropy and high transmission (transmittance greater than or equal to 95%), so as to ensure that the acoustic metasurface composed of multiple units with different phase delays forms a low-energy-loss and left-right mirror-symmetric scattered sound field under forward and reverse incident conditions.

Description

Technical Field

[0001] This invention relates to the field of acoustic tweezers technology, and more particularly to an acoustic metasurface device for localized multidimensional manipulation of millimeter-scale particles. Background Technology

[0002] Acoustic tweezers work by creating a specific acoustic field environment using sound waves. As sound waves propagate in space, their energy distribution forms a specific pattern. By precisely designing and controlling the parameters of the sound waves, a specific acoustic field environment can be created around tiny objects, thereby generating a sound pressure gradient on the object's surface. The uneven distribution of sound pressure leads to the generation of force, thus achieving indirect control of particles.

[0003] In existing literature on aeroacoustics, the control of levitation and rotation of individual particles mainly relies on phased arrays composed of a large number of loudspeakers. While this method can achieve particle manipulation, the system is complex and bulky. Introducing acoustic metasurfaces into acoustic tweezers technology and fabricating passive acoustic tweezers devices has, to some extent, overcome the complexity and size problems of active acoustic tweezers devices. However, current research mainly focuses on particle levitation manipulation, and no technology has yet been found that utilizes acoustic metasurfaces to simultaneously achieve particle levitation and rotation, making it difficult to meet the complexity and functional diversity requirements of practical applications. Summary of the Invention

[0004] This invention provides an acoustic metasurface device for localized, multidimensional manipulation of millimeter-scale particles. This invention can simultaneously levitate and rotate a single millimeter-scale particle at a specific frequency. By changing the intensity and initial phase of the incident sound wave, the levitation and rotation speeds of the particles can be manipulated, as detailed below:

[0005] An acoustic metasurface device for local multidimensional manipulation of millimeter-scale particles, the device consisting of N×N units, each unit being arranged in a plane according to a preset phase gradient law;

[0006] Each unit cell of the acoustic metasurface satisfies the condition that, under the condition of incident sound waves applied from both sides, the phase delay of the resulting scattered sound field is 2π / 2 over one period. n A discrete gradient distribution;

[0007] An acoustic metasurface composed of multiple units with different phase delays forms a low-energy-loss sound field with highly symmetrical forward and backward scattered sound fields under both forward and reverse incident plane sound waves.

[0008] Both forward-scattering and backward-scattering sound fields are vortex sound fields. They utilize their unique sound pressure gradient to provide the radiation force and torque required to manipulate particles. Acoustic metasurfaces control the suspension height and rotation of individual millimeter-scale particles by adjusting the background sound pressure amplitude and initial phase.

[0009] By placing acoustic metasurfaces in opposite directions, the forward and reverse spin of particles can be achieved.

[0010] The unit size of each acoustic metasurface is determined by the operating frequency, and the unit size is λ / 2×λ / 2×kλ (k∈[0.8,1.3]).

[0011] The formula for calculating the phase delay is as follows:

[0012]

[0013] Where ω is the angular frequency, c s Let r be the speed of sound, F0 represent the distance from the origin to the focus, and r be the speed of sound. ij Let represent the distance from the element at position (i,j) to the focus, and l be the vortex topological charge. Represents the spiral phase distribution, N x and N y These represent the number of elements in the x and y directions, respectively.

[0014] The acoustic metasurface is composed of 16×16 units, each unit having dimensions of 4.4mm×4.4mm×12mm; each unit contains four baffles.

[0015] The beneficial effects of the technical solution provided by this invention are:

[0016] 1. This invention systematically evaluates its performance and effectiveness in manipulating single millimeter-scale particles through theoretical analysis, simulation, and experimental verification.

[0017] 2. This invention can achieve high precision and high adaptability in suspension and rotation control, providing an efficient solution for customized applications in complex control scenarios;

[0018] 3. This invention can simultaneously achieve particle suspension and rotation manipulation, meeting the practical needs of multi-functionality and providing a new technical approach for precise particle manipulation.

[0019] 4. The solution provided by this invention can expand the practical application fields of acoustic metasurfaces, such as micromanipulation, biomedicine, and microfluidics, laying a certain foundation for future research and development in related fields. Attached Figure Description

[0020] Figure 1 This is a schematic diagram of an acoustic metasurface device for localized multidimensional manipulation of millimeter-scale particles;

[0021] Figure 2 It is the basic configuration of metasurface units;

[0022] Figure 3These are 16 unit configurations obtained after optimizing the unit configuration parameters;

[0023] Figure 4 It has 16 different acoustic responses;

[0024] Figure 5 It is a three-dimensional schematic diagram of the arrangement of metasurface units and the composition of all units;

[0025] Figure 6 These are the theoretical and simulation results of metasurfaces;

[0026] Figure 7 It is a correlation analysis between the theory of scattered sound fields and simulation calculations;

[0027] Figure 8 It involves the analysis of metasurface scattering acoustic field morphology, fluid intensity distribution, and particle force.

[0028] Figure 9 This is a diagram of an acoustic metasurface actually manufactured in China;

[0029] Figure 10 This is a comparison of experimental testing and simulation of forward and reverse scattering sound fields at a distance of 5.5 cm from the metasurface.

[0030] Figure 11 The results are from the forward-scattering sound field measurements at a height of 3–8 cm from the metasurface.

[0031] Figure 12 It is a comparison of the correlation between experimental testing and theoretical calculation of the sound field;

[0032] Figure 13 This is a screenshot from a video showing particle manipulation.

[0033] Among them, 1-acoustic metasurface; 2-forward incident plane sound wave; 3-forward scattered sound field; 4-reverse incident plane sound wave; 5-reverse scattered sound field; 6-force and torque on the particle. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments of the present invention will be described in further detail below.

[0035] An acoustic metasurface device for local multidimensional manipulation of millimeter-scale particles, the device consists of N×N units, each unit being arranged in a plane according to a preset phase gradient law;

[0036] Each element of the acoustic metasurface 1 needs to satisfy the condition that, under the condition of incident sound waves applied from both sides, the phase delay of the resulting scattered sound field is 2π / 2 over one period. nThere are discrete gradient distributions (n ​​is an integer greater than or equal to 1). Furthermore, the unit configuration of each acoustic metasurface 1 must satisfy the requirements of biisotropy and high transmittance (transmittance greater than or equal to 95%).

[0037] An acoustic metasurface 1, composed of multiple units with different phase delays, forms a low-energy-loss sound field 3 and a highly symmetrical sound field 5 under forward-incident plane sound waves 2 and reverse-incident plane sound waves 4. The size of each metasurface unit is determined by the operating frequency, and the unit size is λ / 2×λ / 2×kλ (k∈[0.8,1.3]).

[0038] Both the forward-scattering sound field 3 and the reverse-scattering sound field 5 are vortex sound fields, utilizing their unique sound pressure gradients to provide the radiation force and torque required to manipulate particles. The acoustic metasurface 1 can flexibly control the suspension height and rotation of individual millimeter-scale particles by adjusting the background sound pressure amplitude and initial phase.

[0039] By placing the acoustic metasurface 1 in the forward and reverse directions, the forward and reverse spin of particles can be realized.

[0040] In a preferred embodiment, the acoustic metasurface 1 is composed of 16×16 units, each unit measuring 4.4mm×4.4mm×12mm. Each unit contains four baffles, the size and position of which are precisely determined using an optimization algorithm to ensure minimal target phase shift error for all units and maintain a transmittance greater than 97%. Subsequently, these units are combined according to specific rules to form the desired acoustic metasurface, successfully achieving precise manipulation of individual millimeter-scale particles at a working frequency of 40kHz.

[0041] In this invention, the elements are arranged in a specific spiral pattern to generate a vortex sound field. By utilizing the pressure gradient and momentum transfer effect in the sound field and adjusting the background sound pressure amplitude of the incident sound wave, the suspension height and rotation of individual millimeter-scale particles can be precisely controlled. The arrangement of the elements follows a phase delay array design, and the phase delay of each element is distributed according to a preset rule:

[0042]

[0043] Where ω is the angular frequency, c s Let r be the speed of sound, F0 represent the distance from the origin to the focus, and r be the speed of sound. ij Let represent the distance from the element at position (i,j) to the focus, and l be the vortex topological charge. Represents the spiral phase distribution, N x and N y These represent the number of elements in the x and y directions, respectively.

[0044] Furthermore, the acoustic radiation force and acoustic radiation torque of the target particle are calculated using the Huygens-Fresnel principle and the surface integral method, thereby more accurately controlling the suspension and rotation state of the particle.

[0045] Furthermore, the unit size of the acoustic metasurface 1 needs to be determined based on several factors, including: the operating frequency of the sound wave, the acoustic properties of the selected material (e.g., acoustic impedance, density, elastic modulus, etc.), and the phase delay gradient and scattering effect required for the sound field design.

[0046] Furthermore, the unit cells of the acoustic metasurface 1 must satisfy biisotropy, meaning that when the same incident wave is applied to both sides, the phase shift and transmission amplitude are the same, and the phase delay of the resulting scattered sound field is 2π / 2 over one period. n There are discrete gradient distributions (n ​​is an integer greater than or equal to 1), and the phase delay between adjacent units is π / 2. n-1 It is worth noting that, during application, there should be at least two or more unit structures; the higher the unit resolution, the more perfect the reproduced sound field.

[0047] Furthermore, the unit cells of the acoustic metasurface 1 need to meet the high transmission requirement (transmittance greater than or equal to 95%), so as to ensure that the acoustic metasurface 1, composed of multiple units with different phase delays, has low energy loss and the forward scattered sound field 3 and the back scattered sound field are highly symmetrical 5 under forward and reverse incident conditions.

[0048] In one illustrative embodiment, the acoustic metasurface (1) consists of 16×16 units, operates at a frequency of 40kHz, and the unit size is 4.4mm×4.4mm×12mm.

[0049] In one illustrative embodiment, in order to suspend a particle with a diameter of 2 mm and a density of 20-25 kg / m³ at a position 5.5 cm away from the acoustic metasurface 1... 3 The particle; in this embodiment of the invention, the surface integration method was used to test the acoustic radiation force and torque of the particle at a height of 5.5 cm under different F0 conditions with l=1. Finally, F0=9.43 cm was selected, and the background sound pressure amplitude was set to 196.47 Pa.

[0050] In one illustrative embodiment, the acoustic metasurface 1 has four baffles inside its unit cells, the positions and sizes of which are determined by multiple parameters. Through parameter optimization, the unit cells of the acoustic metasurface 1 can achieve a scattered sound field phase delay distribution of 16 discrete gradients (n=4) within one period under the condition that incident sound waves are applied from both sides. The phase delay difference between adjacent units is π / 8, satisfying the requirement of biisotropy. Furthermore, the transmittance of the unit cells is greater than 97%, satisfying the requirement of high transmittance.

[0051] In one illustrative embodiment, the unit arrangement of the acoustic metasurface 1) is arranged according to the phase array (which needs to be divided into 16 discrete values) calculated under F0 = 9.43 cm and l = 1.

[0052] In one illustrative embodiment, the Pearson correlation coefficient is used to quantitatively analyze the error between theory, simulation, and experiment.

[0053] Figure 1 This is a schematic diagram provided by an embodiment of the present invention for simultaneously manipulating particle suspension and rotation in the field of aeroacoustics.

[0054] Figure 2 This is the basic unit configuration of metasurface 1 in an exemplary embodiment of the present invention. The unit has four baffles inside, and the position and size of the baffles are determined by 12 parameters.

[0055] like Figure 3 It is based on Figure 2 The exemplary embodiment shows 16 optimized unit configurations derived from the basic configuration. The phase delay between adjacent units is π / 8.

[0056] Figure 4 yes Figure 3 The acoustic response of the 16 units in the exemplary embodiment can be seen from the phase and transmittance curves. The scattered sound fields formed by the forward and reverse incident of the 16 units have a very small phase delay error with the target, and the transmittance is greater than 97%.

[0057] Figure 5 It is based on Figure 3 A schematic diagram of an acoustic metasurface 1 composed of 16 units arranged in a predetermined distribution pattern in an exemplary embodiment.

[0058] Figure 6 The sound field theoretical calculation results in the exemplary embodiments of the present invention and Figure 5 Simulation results of acoustic metasurface 1 in the exemplary embodiment. Figure 7 The figure shows the correlation curves of the acoustic field amplitude and phase between the theoretical and simulation results. As can be seen from the figure, the theoretical calculation results are in good agreement with the simulation data, especially at a distance of 5.5 cm from the acoustic metasurface 1, where the overall similarity of the amplitude field and phase field can reach more than 98.7% and 98.1%, respectively.

[0059] Figure 8 yes Figure 5 The exemplary embodiment of the acoustic metasurface 1 includes a forward-scattering sound field 3 morphology, fluid intensity, and force analysis. As can be seen from the figure, the force and torque values ​​calculated by theory and simulation are in good agreement.

[0060] Figure 9 yes Figure 5An exemplary embodiment of the acoustic metasurface 1 is shown in the actual printing effect diagram. The specimen was prepared using the Mofang microArchS240 ultra-high precision 3D printing system (processing accuracy up to 0.1 mm) and HTL resin material.

[0061] Figure 10 yes Figure 9 Experimental test results of the printed acoustic metasurface 1 in the exemplary embodiment, placed in the forward direction 2 and the reverse direction 4, with planar sound waves applied. The forward scattered sound field 3 and the reverse scattered sound field 4 at a distance of 5.5 cm from the metasurface exhibit extremely high symmetry, consistent with theoretical and simulation results.

[0062] Figure 11 yes Figure 9 Detailed experimental results of the forward scattering sound field 3 of the acoustic metasurface 1 in the exemplary embodiment. Comparison with theoretical and simulation calculation results ( Figure 6 In comparison, the experimental data and simulation results show excellent agreement, verifying the accuracy and reliability of the metasurface design.

[0063] Figure 12 yes Figure 9 The correlation curve between the experimental test and the theoretical sound field of the acoustic metasurface 1 in the exemplary embodiment is shown. At a height of 5.5 cm from the metasurface, the sound field amplitude can reach over 75%, and the phase can reach 21%, at the center. The sound field amplitude can reach over 59%, and the phase can reach 78%, which is sufficient to prove that the present invention has high accuracy.

[0064] Figure 13 yes Figure 9 A video screenshot of the acoustic metasurface 1 in an exemplary embodiment actually manipulating particles. For the first 6.5 seconds, particles can be simultaneously suspended and rotated. After 6.5 seconds, due to the continuously increasing rotational speed of the particles and other uncontrollable factors, they fall. The suspension height has an error of approximately 10% compared to the expected height.

[0065] Unless otherwise specified, the model numbers of the various devices in this embodiment of the invention are not limited, and any device that can perform the above functions is acceptable.

[0066] Those skilled in the art will understand that the accompanying drawings are merely schematic diagrams of a preferred embodiment, and the sequence numbers of the above embodiments of the present invention are for descriptive purposes only and do not represent the superiority or inferiority of the embodiments.

[0067] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An acoustic metasurface device for localized, multidimensional manipulation of millimeter-scale particles, characterized in that, The device consists of N×N units, each unit being arranged in a plane according to a preset phase gradient law; Each unit cell of the acoustic metasurface satisfies the condition that, under the condition of incident sound waves applied from both sides, the phase delay of the resulting scattered sound field is approximately equal to the phase delay over one period. A discrete gradient distribution; An acoustic metasurface composed of multiple units with different phase delays forms a low-energy-loss sound field with highly symmetrical forward and backward scattered sound fields under both forward and reverse incident plane sound waves. Both forward-scattering and backward-scattering sound fields are vortex sound fields. They utilize their unique sound pressure gradient to provide the radiation force and torque required to manipulate particles. Acoustic metasurfaces control the suspension height and rotation of individual millimeter-scale particles by adjusting the background sound pressure amplitude and initial phase. By placing acoustic metasurfaces in opposite directions, the forward and reverse spin of particles can be achieved. The formula for calculating phase delay is: ； in, Angular frequency, For the speed of sound, This represents the distance from the origin to the focus. Representing the The distance from the cell at the location to the focal point. For the vortex topological charge number, Represents a spiral phase distribution. and These represent the number of elements in the x and y directions, respectively.

2. The acoustic metasurface device for localized multidimensional manipulation of millimeter-scale particles according to claim 1, characterized in that, The unit size of each acoustic metasurface is determined by the operating frequency, and the unit size is...

3. The acoustic metasurface device for localized multidimensional manipulation of millimeter-scale particles according to claim 1, characterized in that, The acoustic metasurface is composed of 16×16 units, each unit measuring 4.4mm×4.4mm×12mm; each unit contains four baffles.

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