Acoustic capture and manipulation device and method based on reconfigurable magnetofluid holographic lens

Abstract

The present invention discloses an acoustic capture and manipulation device and method based on a reconfigurable magnetofluid holographic lens. A magnetosphere is provided on the inner bottom surface of a manipulation cavity, suspended particles are suspended above the magnetosphere, a piezoelectric chip is located directly below the manipulation cavity, a U-shaped interdigital electrode is provided between the piezoelectric chip and the manipulation cavity, the piezoelectric chip is fixedly mounted with a grid bottom plate, and a permanent magnet layer is embedded in a groove of the grid bottom plate; the method includes injecting liquid magnetosphere, embedding a permanent magnet layer in the grid bottom plate, the liquid magnetosphere forms a magnetosphere under the action of the magnetic field of the permanent magnet layer, the piezoelectric chip generates surface acoustic waves under the excitation of the U-shaped interdigital electrodes, the surface acoustic waves induce the magnetosphere to vibrate and generate an acoustic pressure field, and the suspended particles are captured above the magnetosphere in a specific arrangement under the action of the acoustic pressure field. The present invention can realize non-contact reconfigurable precise capture of particles and manipulation of complex array arrangements, and has the characteristics of high manipulation accuracy, high equipment integration, strong controllability, and non-contact.

Description

Technical Field

[0001] The present invention relates to an acoustic capture and manipulation device and method in the field of particle manipulation technology, and in particular to an acoustic capture and manipulation device and method based on a reconfigurable magnetofluid holographic lens. Background Art

[0002] With the rapid development of microparticle manipulation technologies, including optical tweezers, magnetic tweezers, and dielectrophoresis, micromanipulation techniques have been widely used to capture single viruses, bacteria, and cells. Among these techniques, optical tweezers offer the highest spatial resolution and have been used for research ranging from single-molecule manipulation to cellular manipulation. However, optical tweezers require complex optical components, including high-power lasers and high-numerical-aperture objectives, and are potentially destructive to biological samples. Acoustic-based microparticle manipulation offers a non-invasive and label-free alternative to optical tweezers. It offers significant advantages in massively parallel manipulation and can manipulate microparticles ranging from nanometer to millimeter scales. Acoustic-based microparticle manipulation often relies on the manipulation of standing wave fields. The superposition of sound waves propagating in different directions generates a periodic grid-like acoustic pressure field, enabling the capture of microparticles at specific locations.

[0003] However, this method cannot flexibly customize the desired arbitrary pattern of particle arrangement arrays. In order to achieve more complex sound pressure field distribution, researchers have proposed acoustic holography for physical object image reconstruction. Regarding acoustic holography technology in the field of ultrasound, there are two commonly used configurations: either use a phased array composed of multiple transducers, or place an acoustic holographic lens in the beam propagation path, which discretizes the beam propagation path and reconstructs the wavefront to achieve customization of the sound pressure field. However, the phase programming control between multiple transducers is very complicated, and the acoustic lens with complex geometric morphology can only form a specific sound pressure field and cannot achieve real-time control of the sound pressure field, which means that this technology is severely limited in practical applications. Due to these limitations, particle manipulation technology based on acoustic holography has so far been limited to proof-of-concept demonstrations. Summary of the Invention

[0004] In order to solve the problems of conventional acoustic holography in effectively capturing particles and the inability to control the geometric morphology of the acoustic holographic lens in real time during manipulation, the present invention proposes an acoustic capture and manipulation device and method based on a reconfigurable magnetofluid holographic lens.

[0005] The technical solution adopted in the present invention is as follows:

[0006] 1. An acoustic capture and manipulation device based on a reconfigurable magnetofluid holographic lens:

[0007] The control chamber comprises a magnetic flux layer, a control cavity, U-shaped interdigital electrodes, a piezoelectric chip, a rectangular grid bottom plate, a permanent magnet layer, and suspended particles. The control cavity is a rectangular shell with an open top. The magnetic flux layer is arranged on the inner bottom surface of the control cavity. The suspended particles are suspended above the magnetic flux layer. The piezoelectric chip is located directly below the control cavity. The U-shaped interdigital electrodes are arranged between the upper surface of the piezoelectric chip and the lower surface of the control cavity. The grid bottom plate is fixedly mounted on the lower surface of the piezoelectric chip. The upper part of the grid bottom plate is provided with a plurality of grooves. The permanent magnet layer is embedded in the grooves of the grid bottom plate.

[0008] Liquid magnetic fluid forms a solid magnetosphere under the action of the magnetic field of the permanent magnet layer. The piezoelectric chip generates surface acoustic waves under the excitation of the U-shaped interdigitated electrodes. Under the action of the surface acoustic waves, the magnetosphere generates an acoustic pressure field for capturing suspended particles. By changing the shape of the permanent magnet layer, the shape of the magnetosphere and the sound pressure distribution of the sound pressure field are changed, thereby realizing the manipulation of the arrangement of suspended particles.

[0009] A permanent magnet slot array is provided on the upper portion of the grid bottom plate, and the permanent magnet slot array is mainly formed by a plurality of grooves arranged in a rectangular array at intervals; the permanent magnet layer is one of a strip array permanent magnet layer, a ring permanent magnet layer and a tetragonal lattice permanent magnet layer;

[0010] The strip array permanent magnet layer is mainly formed by a plurality of straight magnetic paths evenly spaced along the first center line of the grid base plate, each straight magnetic path is arranged along the second center line of the grid base plate, the first center line and the second center line of the grid base plate are perpendicular, and each straight magnetic path is mainly composed of a plurality of permanent magnets arranged in sequence along the second center line of the grid base plate;

[0011] The annular permanent magnet layer is mainly composed of two coaxially arranged annular magnetic paths, inner and outer, each of which is an annular structure composed of a plurality of permanent magnets arranged in sequence;

[0012] The tetragonal lattice permanent magnet layer is mainly formed by a plurality of oblique magnetic paths evenly spaced along the first diagonal direction of the grid base plate, each oblique magnetic path is arranged along the second diagonal direction of the grid base plate, and each oblique magnetic path is mainly composed of a plurality of permanent magnets arranged in sequence along the second diagonal direction of the grid base plate;

[0013] The permanent magnets are all embedded in the grooves of the permanent magnet slot array.

[0014] The magnetic flow layer is mainly one of a strip array magnetic flow layer, a ring magnetic flow layer and a square lattice magnetic flow layer;

[0015] When the permanent magnet layer adopts a strip array permanent magnet layer, the magnetic flow layer is a strip array magnetic flow layer, and the strip array magnetic flow layer is mainly formed by a plurality of strip magnetic fluids evenly spaced along the first center line direction of the grid bottom plate, each strip magnetic fluid is arranged along the second center line direction of the grid bottom plate, and the cross section of the strip magnetic fluid is semi-elliptical; the number and arrangement position of the linear magnetic paths in the permanent magnet layer are the same as those of the strip magnetic fluids and are aligned;

[0016] When the permanent magnet layer adopts an annular permanent magnet layer, the magnetic flow layer is an annular magnetic flow layer, and the annular magnetic flow layer is mainly composed of two coaxially arranged inner and outer circles of annular magnetic fluid, and the annular magnetic fluid is coaxially placed on the inner surface of the control cavity; the annular magnetic paths in the permanent magnet layer are the same in number and arrangement position as the annular magnetic fluid and are aligned;

[0017] When the permanent magnet layer adopts a tetragonal lattice permanent magnet layer, the magnetic fluid layer is a tetragonal lattice magnetic fluid layer, and the tetragonal lattice permanent magnet layer is mainly formed by a number of magnetic fluid protrusions tightly arranged in a rectangular array; the number of magnetic fluid protrusions is the same as that of the permanent magnets in the oblique magnetic path, and the vertices of the magnetic fluid protrusions are distributed in the same position as and aligned with the arrangement position of the permanent magnets in the oblique magnetic path.

[0018] When the permanent magnet layer adopts a strip array permanent magnet layer, a plurality of suspended particles are evenly spaced and arranged along the second center line of the grid base plate to form a straight particle path, and the straight particle path is suspended between two adjacent strip magnetic fluids, so that the straight particle path and the strip magnetic fluid are alternately arranged along the first center line of the grid base plate;

[0019] When the permanent magnet layer is an annular permanent magnet layer, a plurality of suspended particles are evenly spaced along the circumference of the annular magnetic fluid to form an annular particle path, and the annular particle path is suspended between the inner and outer annular magnetic fluids;

[0020] When the permanent magnet layer adopts a tetragonal lattice permanent magnet layer, a number of suspended particles are evenly spaced along the second diagonal direction of the grid base plate to form an oblique particle path. The oblique particle path is suspended in the depression between the magnetic fluid protrusions, and the oblique particle path and the oblique magnetic path are alternately arranged along the first diagonal direction of the grid base plate.

[0021] The U-shaped interdigitated electrodes are made of single metal aluminum through a magnetron sputtering process.

[0022] The liquid magnetic fluid is an alkane-based magnetic fluid, and the functional medium in the liquid magnetic fluid is ferroferric oxide nanoparticles.

[0023] The suspended particles are made of organic polymers without electromagnetic properties.

[0024] 2. An acoustic capture and manipulation method based on a reconfigurable magnetic fluid holographic lens, comprising the following steps:

[0025] Step 1: First, liquid magnetic fluid is injected into the control cavity, and then a permanent magnet layer is embedded in the permanent magnet slot array of the grid base. Under the action of the magnetic field generated by the permanent magnet layer, the liquid magnetic fluid solidifies into a solid magnetic fluid layer of corresponding shape;

[0026] Step 2: An external alternating current signal is input into the U-shaped interdigital electrodes. The U-shaped interdigital electrodes convert the AC signal into a sinusoidal excitation signal and input it into the piezoelectric chip. The sinusoidal excitation signal causes the upper surface of the piezoelectric chip to excite a two-dimensional surface acoustic wave (SAW). The SAW propagates upward into the magnetosphere, thereby inducing vibrations in the magnetosphere's magnetic fluid. The magnetic fluid then diffracts in the air to generate an acoustic pressure field.

[0027] Step 3: Suspended particles are placed into the control cavity. Under the action of the acoustic radiation force in the acoustic pressure field, the suspended particles are captured above the magnetosphere in a specific arrangement;

[0028] Step 4: Adjust the shape of the permanent magnet layer and repeat steps 1 to 3 to adjust the shape of the magnetosphere and the sound pressure distribution of the sound pressure field, thereby achieving control over the arrangement of the suspended particles.

[0029] In step 1, under the action of the magnetic field generated by the permanent magnet layer, the liquid magnetic fluid solidifies into a solid magnetic fluid layer of corresponding shape as follows:

[0030] Under the action of the strip array permanent magnet layer, the liquid magnetic fluid solidifies into a strip array magnetic flow layer; under the action of the annular permanent magnet layer, the liquid magnetic fluid solidifies into an annular magnetic flow layer; under the action of the tetragonal lattice permanent magnet layer, the liquid magnetic fluid solidifies into a tetragonal lattice magnetic flow layer.

[0031] In step 3, the suspended particles are captured above the magnetosphere in a specific arrangement as follows:

[0032] Under the action of the acoustic pressure field of the strip array magnetofluid layer, the suspended particles are evenly spaced along the second center line of the grid bottom plate to form a straight particle path, which is suspended between two adjacent strips of magnetic fluid.

[0033] Under the action of the acoustic pressure field of the annular magnetosphere, the suspended particles are evenly spaced along the circumference of the annular magnetic fluid to form an annular particle path, which is suspended between the inner and outer annular magnetic fluids.

[0034] Under the action of the acoustic pressure field of the tetragonal lattice magnetofluid layer, the suspended particles are evenly spaced along the second diagonal direction of the grid bottom plate to form an oblique particle path, which is suspended in the depressions between the magnetic fluid protrusions.

[0035] Leveraging the characteristics of magnetic fluids, which can achieve precise adjustment of their geometric shape under the influence of a magnetic field and diffraction of their acoustic impedance, thus functioning as an acoustic holographic lens, the present invention proposes an acoustic capture and manipulation device and method based on a reconfigurable magnetic fluid holographic lens. By embedding a permanent magnet layer in a grid base plate arranged at the bottom, a magnetic field with a specific geometric shape is generated, causing the magnetic fluid in the manipulation cavity to form an acoustic holographic lens with a specific surface microstructure, which is used to generate an acoustic pressure field of a corresponding shape. Changing the arrangement of the permanent magnet layer enables reconfigurable morphology control of the magnetic fluid acoustic holographic lens. By inputting an alternating current signal into the U-shaped interdigitated electrodes arranged on a piezoelectric chip, an inverse piezoelectric effect is generated on the chip, exciting high-frequency surface acoustic waves, thereby driving the magnetic fluid acoustic holographic lens above the electrodes to vibrate and form an acoustic pressure field of a corresponding shape. At this time, suspended particles in the manipulation cavity are captured by the acoustic pressure field and gathered at the trough of the acoustic pressure field. By changing the morphology of the magnetic fluid acoustic holographic lens, precise manipulation of suspended particles can be achieved.

[0036] The present invention has the following beneficial effects:

[0037] 1. The present invention utilizes the characteristics of magnetic fluid that can achieve precise adjustment of its own geometric morphology under the action of a magnetic field and that its acoustic impedance can achieve diffraction, thus having the function of an acoustic holographic lens, thereby realizing high-precision particle capture and manipulation based on a reconfigurable acoustic holographic lens.

[0038] 2. The equipment used in the present invention is simple and easy to operate, and has no requirements on the electromagnetic properties of the particles themselves, thereby enabling the precise capture and flexible manipulation of particles such as organic polymer molecules and biological cells.

[0039] 3. The present invention has the characteristics of being easy to combine with other microfluidic technologies and having low energy consumption.

[0040] 4. The present invention can achieve high-precision capture and reconfigurable manipulation of particles, and has the characteristics of high manipulation accuracy, high equipment integration, strong controllability, and non-contact. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] Figure 1 Schematic diagram of the device structure of the present invention;

[0042] Figure 2 Schematic diagram of the principle of acoustic capture of microparticles by reconfigurable magnetofluidic holographic lens;

[0043] Figure 3 Schematic diagram of capturing and manipulating particles using a nearly circular acoustic holographic lens;

[0044] Figure 4 Schematic diagram of capturing and manipulating particles using a hexagonal ring acoustic holographic lens;

[0045] Figure 5 Schematic diagram of the capture and manipulation of particles by the tetragonal lattice morphoacoustic holographic lens;

[0046] In the figure: 1. Magnetosphere; 2. Control cavity; 3. U-shaped interdigitated electrode; 4. Piezoelectric chip; 5. Grid base plate; 6. Permanent magnet layer; 7. Suspended particles; 8. Acoustic radiation force; 9. Surface acoustic wave; 10. Approximately annular acoustic holographic lens; 11. Approximately annular permanent magnet layer; 12. Hexagonal ring acoustic holographic lens; 13. Hexagonal ring permanent magnet layer; 14. Tetragonal lattice acoustic holographic lens; 15. Tetragonal lattice permanent magnet layer. DETAILED DESCRIPTION

[0047] The present invention will be further described below with reference to the accompanying drawings and examples, but the embodiments of the present invention are not limited thereto.

[0048] like Figure 1 As shown, it includes a magnetosphere 1, a control cavity 2, a U-shaped interdigitated electrode 3, a piezoelectric chip 4, a rectangular grid bottom plate 5, a permanent magnet layer 6 and suspended particles 7; the control cavity 2 is a rectangular shell with an open upper end, the magnetosphere 1 is arranged on the inner bottom surface of the control cavity 2, the suspended particles 7 are suspended above the magnetosphere 1, and there is no contact between the suspended particles 7 and the magnetosphere 1, the piezoelectric chip 4 is located directly below the control cavity 2, and a U-shaped interdigitated electrode 3 is arranged between the upper surface of the piezoelectric chip 4 and the lower surface of the control cavity 2, the grid bottom plate 5 is fixedly installed on the lower surface of the piezoelectric chip 4, and a plurality of grooves are opened on the upper part of the grid bottom plate 5, and the permanent magnet layer 6 is embedded in the grooves of the grid bottom plate 5. The device is mainly composed of the control cavity 2, the U-shaped interdigitated electrode 3, the piezoelectric chip 4, and the grid bottom plate 5 stacked in sequence from top to bottom, and the U-shaped interdigitated electrode 3 is bonded to the upper surface of the piezoelectric chip 4;

[0049] like Figure 2 As shown, the liquid magnetic fluid forms a solid magnetosphere 1 under the action of the magnetic field of the permanent magnet layer 6, and the piezoelectric chip 4 generates a surface acoustic wave 9 under the excitation of the U-shaped interdigitated electrode 3 connected to the external electrical signal. Under the action of the surface acoustic wave 9, the magnetosphere 1 generates an acoustic pressure field for capturing suspended particles 7. By changing the shape of the permanent magnet layer 6, the shape of the magnetosphere 1 and the sound pressure distribution of the sound pressure field are changed, thereby realizing the manipulation of the arrangement of the captured suspended particles 7.

[0050] The permanent magnet layer 6 is used to control the shape of the magnetosphere 1 , and thus control the arrangement of the suspended particles 7 .

[0051] A permanent magnet slot array is provided on the upper portion of the grid base plate 5. The permanent magnet slot array is mainly formed by a plurality of grooves arranged in a rectangular array at intervals. The permanent magnet layer 6 is one of a strip array permanent magnet layer, a ring permanent magnet layer and a tetragonal lattice permanent magnet layer.

[0052] like Figure 1 As shown, the strip array permanent magnet layer is mainly formed by a plurality of straight magnetic paths evenly spaced along the first center line of the grid base plate 5, each straight magnetic path is arranged along the second center line of the grid base plate 5, the first center line and the second center line of the grid base plate 5 are perpendicular, and each straight magnetic path is mainly composed of a plurality of permanent magnets arranged in sequence along the second center line of the grid base plate 5;

[0053] like Figure 3 and Figure 4 As shown, the annular permanent magnet layer is mainly composed of two coaxially arranged inner and outer annular magnetic paths. The annular magnetic path is arranged in the middle of the grid base plate 5 and is coaxial with the grid base plate 5. Each annular magnetic path is an annular structure mainly composed of a plurality of permanent magnets arranged in sequence along the circumference of the grid base plate 5. The annular structure includes an approximately circular ring structure and a hexagonal ring structure.

[0054] like Figure 5 As shown, the tetragonal lattice permanent magnet layer is mainly formed by a plurality of oblique magnetic paths evenly spaced along the first diagonal direction of the grid base plate 5, each oblique magnetic path is arranged along the second diagonal direction of the grid base plate 5, the first diagonal and the second diagonal of the grid base plate 5 are perpendicular, and each oblique magnetic path is mainly composed of a plurality of permanent magnets arranged in sequence along the second diagonal direction of the grid base plate 5; the permanent magnets in the strip array permanent magnet layer, the annular permanent magnet layer and the tetragonal lattice permanent magnet layer are all embedded in the grooves of the permanent magnet slot array.

[0055] The magnetosphere 1 is mainly one of a strip array magnetosphere, a ring magnetosphere and a tetragonal lattice magnetosphere;

[0056] like Figure 1 As shown, when the permanent magnet layer 6 adopts a strip array permanent magnet layer, the magnetic flow layer 1 is a corresponding strip array magnetic flow layer, which is mainly formed by a plurality of strip magnetic fluids evenly spaced along the first center line direction of the grid bottom plate 5. Each strip magnetic fluid is arranged along the second center line direction of the grid bottom plate 5. The cross section of the strip magnetic fluid is semi-elliptical, the rectangular side of the strip magnetic fluid contacts the inner bottom surface of the control cavity 2, and the arcuate side of the strip magnetic fluid faces upward; the number and arrangement position distribution of the linear magnetic paths in the permanent magnet layer 6 are the same as those of the strip magnetic fluids, and the arrangement positions are aligned one by one in the vertical direction;

[0057] like Figure 3 and Figure 4As shown, when the permanent magnet layer 6 adopts an annular permanent magnet layer, the magnetic fluid layer 1 is a corresponding annular magnetic fluid layer, which is mainly composed of two coaxially arranged inner and outer circles of annular magnetic fluid. The annular magnetic fluid is coaxially placed on the inner surface of the control cavity 2, and the annular magnetic fluid is located in the middle of the control cavity 2. The annular magnetic fluid layer has an approximately circular ring structure or a hexagonal ring structure; the number and arrangement position distribution of the annular magnetic paths in the permanent magnet layer 6 are the same as those of the annular magnetic fluid, and the arrangement positions are aligned one by one in the vertical direction;

[0058] like Figure 5 As shown, when the permanent magnet layer 6 adopts a tetragonal lattice permanent magnet layer, the magnetic fluid layer 1 is a corresponding tetragonal lattice magnetic fluid layer, and the tetragonal lattice permanent magnet layer is mainly formed by a number of magnetic fluid protrusions tightly arranged in a rectangular array; the number of magnetic fluid protrusions is the same as that of the permanent magnets in the oblique magnetic path, and the vertices of the magnetic fluid protrusions are distributed in the same arrangement position as the permanent magnets in the oblique magnetic path, and the arrangement positions are aligned one by one in the vertical direction.

[0059] The magnetic fluid includes strip magnetic fluid, annular magnetic fluid and magnetic fluid protrusion.

[0060] When the permanent magnet layer 6 is a strip array permanent magnet layer, a plurality of suspended particles 7 are evenly spaced and arranged along the second centerline direction of the grid base plate 5 to form a straight particle path. The straight particle path is suspended between two adjacent strip magnetic fluids, so that the straight particle path and the strip magnetic fluid are alternately arranged along the first centerline direction of the grid base plate 5.

[0061] When the permanent magnet layer 6 is an annular permanent magnet layer, a plurality of suspended particles 7 are evenly spaced along the circumference of the annular magnetic fluid to form an annular particle path. The annular particle path is suspended between the inner and outer annular magnetic fluids, and the annular particle path is approximately a circular ring structure or a hexagonal ring structure.

[0062] When the permanent magnet layer 6 adopts a tetragonal lattice permanent magnet layer, a number of suspended particles 7 are evenly spaced along the second diagonal direction of the grid base plate 5 to form an oblique particle path. The oblique particle path is suspended in the depression between the magnetic fluid protrusions, and the oblique particle path and the oblique magnetic path are alternately arranged in the horizontal direction along the first diagonal direction of the grid base plate 5.

[0063] The U-shaped interdigital electrodes 3 are made of single metal aluminum by magnetron sputtering.

[0064] The liquid magnetic fluid adopts an alkane-based magnetic fluid, and the functional medium in the liquid magnetic fluid is ferroferric oxide nanoparticles.

[0065] The suspended particles 7 are made of organic polymers having no electromagnetic properties.

[0066] The method of the present invention comprises the following steps:

[0067] Step 1: First, liquid magnetic fluid is injected into the control cavity 2, and then a permanent magnet layer 6 is embedded in the permanent magnet slot array of the grid base 5. Under the action of the magnetic field generated by the permanent magnet layer 6, the liquid magnetic fluid solidifies into a solid magnetic fluid layer 1 of the corresponding shape;

[0068] Step 2: An external alternating current signal is input into the U-shaped interdigital electrode 3. The U-shaped interdigital electrode 3 converts the alternating current signal into a sinusoidal excitation signal and inputs it into the piezoelectric chip 4. The sinusoidal excitation signal causes the upper surface of the piezoelectric chip 4 to emit a two-dimensional surface acoustic wave 9 under the inverse piezoelectric effect. The surface acoustic wave 9 propagates upward into the magnetosphere 1, thereby inducing vibration of the magnetic fluid in the magnetosphere 1. The difference in acoustic impedance between the magnetic fluid and the air causes the magnetic fluid to diffract in the air, generating an acoustic pressure field with a striped morphology.

[0069] The above steps enable the magnetosphere 1 to produce an acoustic holographic lens effect through wavefront reconstruction;

[0070] Step 3: Suspended particles 7 are placed into the control cavity 2. Under the action of the acoustic radiation force 8 in the acoustic pressure field, the suspended particles 7 are captured above the magnetosphere 1 in a specific arrangement, and the suspended particles 7 gather at the trough of the acoustic pressure field.

[0071] Step 4: Adjust the shape of the permanent magnet layer 6 and repeat steps 1 to 3 to adjust the shape of the magnetosphere 1 and the sound pressure distribution of the sound pressure field, thereby achieving control over the arrangement of the suspended particles 7.

[0072] The present invention changes the shape of the magnetosphere 1 , thereby changing the sound pressure distribution of the sound pressure field, thereby achieving control over the arrangement of the suspended particles 7 .

[0073] In step 1, under the action of the magnetic field generated by the permanent magnet layer 6, the liquid magnetic fluid solidifies into a solid magnetic fluid layer 1 of a corresponding shape. Specifically:

[0074] Under the action of the strip array permanent magnet layer, the liquid magnetic fluid solidifies into a strip array magnetic flow layer; under the action of the annular permanent magnet layer, the liquid magnetic fluid solidifies into an annular magnetic flow layer; under the action of the tetragonal lattice permanent magnet layer, the liquid magnetic fluid solidifies into a tetragonal lattice magnetic flow layer.

[0075] In step 3, the suspended particles 7 are captured above the magnetosphere 1 in a specific arrangement as follows:

[0076] Under the action of the acoustic pressure field of the strip array magnetic fluid layer, the suspended particles 7 are evenly spaced along the second centerline direction of the grid base plate 5 to form a straight particle path. The straight particle path is suspended between two adjacent strip magnetic fluids, so that the straight particle path and the strip magnetic fluid are alternately arranged along the first centerline direction of the grid base plate 5.

[0077] Under the action of the acoustic pressure field of the annular magnetic fluid layer, the suspended particles 7 are evenly spaced along the circumference of the annular magnetic fluid to form an annular particle path, which is suspended between the inner and outer annular magnetic fluids.

[0078] Under the action of the square lattice-shaped magnetofluid layer acoustic pressure field, the suspended particles 7 are evenly spaced along the second diagonal direction of the grid bottom plate 5 to form an oblique particle path. The oblique particle path is suspended in the depression between the magnetic fluid protrusions, and the oblique particle path and the oblique magnetic path are alternately arranged along the first diagonal direction of the grid bottom plate 5.

[0079] By arranging the permanent magnet layer 6 as a strip array permanent magnet layer, the magnetofluid layer 1 in the control cavity 2 can be reconstructed into a strip array acoustic holographic lens 10, and the suspended particles 7 are captured at the troughs of the magnetofluid layer 1, thereby presenting the same arrangement as the strip array acoustic holographic lens 10 on a macro scale.

[0080] By arranging the permanent magnet layer 6 into a tetragonal lattice permanent magnet layer 15 , the magnetosphere 1 in the manipulation cavity 2 can be reconstructed into a tetragonal lattice acoustic holographic lens 14 , so that the captured suspended particles 7 are also manipulated to be distributed in the same form.

[0081] By adjusting the permanent magnet layer 6 on the grid base plate 5 to be distributed as an approximately circular permanent magnet layer 11 and a hexagonal permanent magnet layer 13, an approximately circular acoustic holographic lens 10 and a hexagonal acoustic holographic lens 12 can be formed in the control cavity 2, respectively, thereby achieving high-precision control of the suspended particles 7.

[0082] As can be seen from the embodiments, the magnetic fluid can achieve precise adjustment of its own geometric morphology and diffraction of acoustic impedance under the action of a magnetic field, thus having the characteristics of an acoustic holographic lens. High-precision particle capture and manipulation based on a reconfigurable acoustic holographic lens is achieved, with the characteristics of high manipulation accuracy, high equipment integration, strong controllability, and non-contact.

Claims

1. An acoustic capture and manipulation device based on a reconfigurable magnetofluid holographic lens, characterized by: The invention comprises a magnetosphere (1), a control cavity (2), a U-shaped interdigitated electrode (3), a piezoelectric chip (4), a rectangular grid bottom plate (5), a permanent magnet layer (6) and suspended particles (7); the control cavity (2) is a rectangular shell with an upper end open, the magnetosphere (1) is arranged on the inner bottom surface of the control cavity (2), the suspended particles (7) are suspended above the magnetosphere (1), the piezoelectric chip (4) is located directly below the control cavity (2), the U-shaped interdigitated electrode (3) is arranged between the upper surface of the piezoelectric chip (4) and the lower surface of the control cavity (2), the grid bottom plate (5) is fixedly mounted on the lower surface of the piezoelectric chip (4), a plurality of grooves are opened on the upper part of the grid bottom plate (5), and the permanent magnet layer (6) is embedded in the grooves of the grid bottom plate (5); The liquid magnetic fluid forms a solid magnetic fluid layer (1) under the action of the magnetic field of the permanent magnet layer (6); the piezoelectric chip (4) generates a surface acoustic wave (9) under the stimulation of the U-shaped interdigitated electrode (3); under the action of the surface acoustic wave (9), the magnetic fluid layer (1) generates an acoustic pressure field for capturing suspended particles (7); by changing the shape of the permanent magnet layer (6), the shape of the magnetic fluid layer (1) and the sound pressure distribution of the sound pressure field are changed, thereby achieving the control of the arrangement of the suspended particles (7); The upper surface of the piezoelectric chip (4) emits a surface acoustic wave (9) with a two-dimensional waveform under the inverse piezoelectric effect. The surface acoustic wave (9) propagates upward into the magnetosphere (1), thereby inducing vibration of the magnetic fluid in the magnetosphere (1). The difference in acoustic impedance between the magnetic fluid and the air causes the magnetic fluid to diffract in the air, generating an acoustic pressure field with a striped morphology, thereby achieving wavefront reconstruction and causing the magnetosphere (1) to produce an acoustic holographic lens effect. A permanent magnet slot array is provided on the upper portion of the grid bottom plate (5), and the permanent magnet slot array is mainly formed by a plurality of grooves arranged in a rectangular array at intervals; the permanent magnet layer (6) is one of a strip array permanent magnet layer, a ring permanent magnet layer and a square lattice permanent magnet layer; The strip array permanent magnet layer is mainly formed by a plurality of straight magnetic paths evenly spaced along the first center line direction of the grid bottom plate (5), each straight magnetic path is arranged along the second center line direction of the grid bottom plate (5), the first center line and the second center line of the grid bottom plate (5) are perpendicular, and each straight magnetic path is mainly composed of a plurality of permanent magnets arranged in sequence along the second center line direction of the grid bottom plate (5); The annular permanent magnet layer is mainly composed of two coaxially arranged annular magnetic paths, inner and outer, each of which is an annular structure composed of a plurality of permanent magnets arranged in sequence; The tetragonal lattice permanent magnet layer is mainly formed by a plurality of oblique magnetic paths evenly spaced along a first diagonal direction of the grid bottom plate (5), each oblique magnetic path is arranged along a second diagonal direction of the grid bottom plate (5), and each oblique magnetic path is mainly composed of a plurality of permanent magnets arranged in sequence along the second diagonal direction of the grid bottom plate (5); The permanent magnets are all embedded in the grooves of the permanent magnet slot array; The magnetic flow layer (1) is mainly one of a strip array magnetic flow layer, a ring magnetic flow layer and a square lattice magnetic flow layer; When the permanent magnet layer (6) adopts a strip array permanent magnet layer, the magnetic fluid layer (1) is a strip array magnetic fluid layer, and the strip array magnetic fluid layer is mainly formed by a plurality of strip magnetic fluids arranged evenly and spaced along the first center line direction of the grid bottom plate (5), and each strip magnetic fluid is arranged along the second center line direction of the grid bottom plate (5), and the cross section of the strip magnetic fluid is semi-elliptical; the number and arrangement position distribution of the linear magnetic paths in the permanent magnet layer (6) are the same as those of the strip magnetic fluids and are aligned; When the permanent magnet layer (6) is an annular permanent magnet layer, the magnetic fluid layer (1) is an annular magnetic fluid layer, and the annular magnetic fluid layer is mainly composed of two coaxially arranged inner and outer circles of annular magnetic fluid, and the annular magnetic fluid is coaxially placed on the inner surface of the control cavity (2); the annular magnetic paths in the permanent magnet layer (6) are the same in number and arrangement position as the annular magnetic fluid and are aligned; When the permanent magnet layer (6) adopts a tetragonal lattice permanent magnet layer, the magnetic fluid layer (1) is a tetragonal lattice permanent magnet layer, and the tetragonal lattice permanent magnet layer is mainly formed by a plurality of magnetic fluid protrusions tightly arranged in a rectangular array; the number of the magnetic fluid protrusions is the same as that of the permanent magnets in the oblique magnetic path, and the vertices of the magnetic fluid protrusions are distributed in the same position as and aligned with the arrangement position of the permanent magnets in the oblique magnetic path; When the permanent magnet layer (6) is a strip array permanent magnet layer, a plurality of suspended particles (7) are evenly spaced and arranged along the second centerline direction of the grid bottom plate (5) to form a straight particle path, and the straight particle path is suspended between two adjacent strip magnetic fluids, so that the straight particle path and the strip magnetic fluid are alternately arranged along the first centerline direction of the grid bottom plate (5); When the permanent magnet layer (6) is an annular permanent magnet layer, a plurality of suspended particles (7) are evenly spaced along the circumference of the annular magnetic fluid to form an annular particle path, and the annular particle path is suspended between the inner and outer annular magnetic fluids; When the permanent magnet layer (6) adopts a tetragonal lattice permanent magnet layer, a plurality of suspended particles (7) are evenly spaced and arranged along the second diagonal direction of the grid base plate (5) to form an oblique particle path, the oblique particle path is suspended in the depression between the magnetic fluid protrusions, and the oblique particle path and the oblique magnetic path are alternately arranged along the first diagonal direction of the grid base plate (5).

2. The acoustic capture and manipulation device based on a reconfigurable magnetic fluid holographic lens according to claim 1, characterized in that: The U-shaped interdigitated electrodes (3) are made of single metal aluminum through a magnetron sputtering process.

3. The acoustic capture and manipulation device based on a reconfigurable magnetic fluid holographic lens according to claim 1, characterized in that: The liquid magnetic fluid is an alkane-based magnetic fluid, and the functional medium in the liquid magnetic fluid is ferroferric oxide nanoparticles.

4. The acoustic capture and manipulation device based on a reconfigurable magnetic fluid holographic lens according to claim 1, characterized in that: The suspended particles (7) are made of organic polymers without electromagnetic properties.

5. An acoustic capture and manipulation method based on a reconfigurable magnetic fluid holographic lens applied to the device according to any one of claims 1 to 4, characterized in that: The following steps are involved: Step 1: First, liquid magnetic fluid is injected into the control cavity (2), and then a permanent magnet layer (6) is embedded in the permanent magnet slot array of the grid bottom plate (5). Under the action of the magnetic field generated by the permanent magnet layer (6), the liquid magnetic fluid solidifies into a solid magnetic fluid layer (1) of a corresponding shape; Step 2: An external alternating current signal is input into the U-shaped interdigital electrode (3). The U-shaped interdigital electrode (3) converts the alternating current signal into a sinusoidal excitation signal and inputs it into the piezoelectric chip (4). The sinusoidal excitation signal causes the upper surface of the piezoelectric chip (4) to excite a surface acoustic wave (9) having a two-dimensional waveform. The surface acoustic wave (9) propagates upward into the magnetosphere (1), thereby inducing vibration of the magnetic fluid in the magnetosphere (1). The magnetic fluid diffracts in the air to generate an acoustic pressure field. Step 3: Suspended particles (7) are placed into the control cavity (2), and the suspended particles (7) are captured above the magnetosphere (1) in a specific arrangement under the action of the acoustic radiation force (8) in the acoustic pressure field generated by the magnetosphere (1); Step 4: Regulate the shape of the permanent magnet layer (6), and repeat steps 1 to 3 to regulate the shape of the magnetosphere (1) and the sound pressure distribution of the sound pressure field, thereby achieving control over the arrangement of the suspended particles (7).

6. The acoustic capture and manipulation method based on a reconfigurable magnetic fluid holographic lens according to claim 5, characterized in that: In the step 1, under the action of the magnetic field generated by the permanent magnet layer (6), the liquid magnetic fluid solidifies into a solid magnetic fluid layer (1) of a corresponding shape, specifically: Under the action of the strip array permanent magnet layer, the liquid magnetic fluid solidifies into a strip array magnetic flow layer; under the action of the annular permanent magnet layer, the liquid magnetic fluid solidifies into an annular magnetic flow layer; under the action of the tetragonal lattice permanent magnet layer, the liquid magnetic fluid solidifies into a tetragonal lattice magnetic flow layer.

7. The acoustic capture and manipulation method based on a reconfigurable magnetic fluid holographic lens according to claim 5, characterized in that: In step 3, the suspended particles (7) are captured above the magnetosphere (1) in a specific arrangement, specifically: Under the action of the acoustic pressure field generated by the strip array magnetic fluid layer, the suspended particles (7) are evenly spaced along the second center line direction of the grid bottom plate (5) to form a straight particle path, the straight particle path is suspended between two adjacent strip magnetic fluids, and the straight particle path and the strip magnetic fluid are alternately arranged along the first center line direction of the grid bottom plate (5); Under the action of the pressure field generated by the annular magnetic fluid layer, the suspended particles (7) are evenly spaced along the circumference of the annular magnetic fluid to form an annular particle path, and the annular particle path is suspended between the inner and outer annular magnetic fluids; Under the action of the acoustic pressure field generated by the tetragonal lattice-shaped magnetic fluid layer, the suspended particles (7) are evenly spaced along the second diagonal direction of the grid bottom plate (5) to form an oblique particle path, and the oblique particle path is suspended in the depressions between the magnetic fluid protrusions.

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