Piezoelectric-excitation circular-ring-surface micro-control device and working method thereof
Technical Field
The invention relates to the field of piezoelectric transducers, acoustic control and microsphere control, in particular to a piezoelectric-excited micro-control device in a circular ring surface and a working method thereof.
Background
The micro-control technology has wide application prospect in the fields of biology, medical treatment, chemistry and the like. Currently, many types of micromanipulation devices have been developed for the study of micromanipulation techniques. Among them, the micromanipulation devices can be classified into optical tweezers, magnetic tweezers, electrical tweezers, acoustic tweezers (acoustic manipulation), and the like according to the principle on which they are based. However, the optical tweezers may damage the surface of the microparticles due to a large amount of heat generated by the laser in the working process, and the optical tweezers are expensive and complex in structure, and are not suitable for large-scale application. The magnetic tweezers and the electric tweezers have selective properties on the manipulated object, and the manipulated object can be manipulated only by magnetism or electric charge. For particles that do not meet the conditions, magnetic tweezers and electric tweezers are needed to treat the manipulated particles, and the treatment process may damage the particles. Different from the micro control device, the acoustic tweezers have no special requirements on the properties of the controlled object and have the advantages of high biocompatibility, no damage and stable control. Therefore, the sound control has wider application prospect.
Acoustic steering can be divided into surface acoustic waves and bulk acoustic waves according to the type of acoustic wave generated. Surface acoustic waves are typically excited by interdigital transducers, while bulk acoustic waves are typically excited by piezoelectric ceramics. Compared with a bulk acoustic wave device, the surface acoustic wave device has a complex structure and high manufacturing cost. The bulk acoustic wave device has a simple structure, and can effectively control large-scale microparticles (submillimeter-level). The working principle of the bulk acoustic wave micro-control device is mainly that a piezoelectric transducer excites the vibration mode of the device, so that a corresponding sound field is generated. While the microspheres in the liquid environment will move towards the sound pressure node in the sound field. The vibration modes excited by the piezoelectric ceramics can be classified into out-of-plane vibration modes and in-plane vibration modes.
In the out-of-plane vibration mode, the vibration direction of mass points is vertical to the motion direction of the controlled particles, so that the oscillation phenomenon can be generated in the motion of the microspheres, and the control stability is reduced. And the in-plane vibration mode is parallel to the movement direction of the controlled particles due to the particle movement direction, which means that the in-plane vibration mode can be used for improving the control stability of the micro-control device and reducing the oscillation problem in the control process. Therefore, in order to realize the lossless and stable control of the large-scale microparticles, the invention provides a piezoelectric excitation circular ring micro-control device based on in-plane bulk acoustic waves.
Disclosure of Invention
The invention aims to solve the technical problem of providing a piezoelectric-excited micro-control device in a circular ring surface and a working method thereof aiming at the defects related in the background technology.
The invention adopts the following technical scheme for solving the technical problems:
a piezoelectric excitation circular ring surface micro-control device comprises a container, a transducer array and a substrate;
the transducer array includes first to fourth transducers;
the first transducer, the second transducer, the third transducer, the fourth transducer and the fourth transducer are identical in structure and respectively comprise a pre-tightening bolt, a pre-tightening column, a piezoelectric ceramic module, a clamping seat and a connecting platform;
the pre-tightening bolt comprises a nut and a stud; the pre-tightening column is a regular prism or a cylinder, and a countersunk through hole matched with the pre-tightening bolt is formed in the center of one end face of the pre-tightening column;
the connecting table comprises a first connecting part and a second connecting part, wherein the first connecting part is a regular prism or a cylinder, the second connecting part is a regular prism table or a circular table with the same shape of an end face with a larger area and an end face at one end of the first connecting part, and the second connecting part is an end face with a larger area and one end of the first connecting part which are correspondingly and coaxially fixedly connected; the other end of the first connecting part is provided with a threaded hole matched with the pre-tightening bolt;
the piezoelectric ceramic module comprises 2 groups of piezoelectric ceramic pieces, each group of piezoelectric ceramic pieces comprises n annular piezoelectric ceramic pieces, and n is a natural number more than or equal to 1;
the clamping seat comprises a connecting ring, a connecting strip and a fixing part; one end of the connecting strip is fixedly connected with the outer wall of the connecting circular ring and points to the circle center of the connecting circular ring, and the other end of the connecting strip is fixedly connected with the fixing part; the fixed part is fixedly connected with the substrate; grooves vertical to the length direction of the connecting strips are correspondingly arranged on two side surfaces of the connecting strips close to one end of the connecting ring to form flexible hinges;
the stud of the pre-tightening bolt sequentially penetrates through the countersunk through hole of the pre-tightening column, the 1 group of piezoelectric ceramic pieces, the connecting ring of the clamping seat and the other 1 group of piezoelectric ceramic pieces and then is in threaded connection with the threaded hole of the connecting table, and the 2 groups of piezoelectric ceramic pieces are compressed;
the 2 groups of piezoelectric ceramic pieces are symmetrically arranged about the connecting ring, the piezoelectric ceramic pieces in each group of piezoelectric ceramic pieces are polarized along the thickness direction of the piezoelectric ceramic pieces, and the polarization directions of the adjacent piezoelectric ceramic pieces in the same group of piezoelectric ceramic pieces are opposite;
the container is annular, and an annular groove coaxial with the container is formed in the upper end face of the container and used for containing a liquid bearing medium and microspheres to be controlled; four bosses with the same end face shape as the end face with smaller area of the second connecting part are uniformly arranged on the outer wall of the container in the circumferential direction;
the end faces with smaller areas of the second connecting parts of the first transducer, the second transducer and the fourth transducer are fixedly connected with four bosses on the outer wall of the container in a one-to-one correspondence mode, so that the axes of the connecting platforms of the first transducer, the second transducer and the fourth transducer point to the center of the container; and the fixed parts of the first transducer, the second transducer and the fourth transducer are fixedly connected with the upper end face of the substrate.
As a further optimization scheme of the piezoelectric-excitation in-circular-ring-surface micro-manipulation device, the pre-tightening column is a cylinder, the first connecting part is a regular quadrangular prism, and the first connecting part is a regular quadrangular frustum pyramid.
As a further optimized scheme of the piezoelectric-excited in-plane micro-manipulation device, the fixing parts of the first to fourth transducers are strip-shaped, one ends of the fixing parts are vertically and fixedly connected with the corresponding connecting strips, and the fixing parts are fixedly connected with the substrate through bolts.
As a further optimization scheme of the piezoelectric-excitation in-circular-ring micro-manipulation device, n is 2.
The invention also discloses a control method of the piezoelectric excitation circular ring in-plane micro-control device, which comprises the following steps:
arranging the first to fourth transducers on the substrate in a clockwise sequence, and applying first to fourth simple harmonic voltage signals to the first to fourth transducers respectively;
the first simple harmonic voltage signal, the second simple harmonic voltage signal, the third simple harmonic voltage signal, the fourth simple harmonic voltage signal and the fourth simple harmonic voltage signal, the phase difference pi/2, the angular frequency is equal to a preset rotating mode frequency value omega, the phase difference is sequentially, the phase difference is pi/2, the angular frequency is equal to the preset rotating mode frequency value omega, simultaneously, the in the container is excited to generate an in space phase difference, an in the container, and the in the container, the in the plane vibration mode, the in the container, the in the mode, and the mode, and the in the mode, the container, and the in the container, and the exciting, and the in the container, and the exciting, and the in the container, and the in the container, and the in the excitation, and the container, and the in the container, and the in the container, the in order, the container, the in the excitation, the in the excitation, and the in the container, the in the excitation, the container, the excitation, the in;
under the traveling wave mode, generating a corresponding sound pressure field in a bearing liquid medium in the circular ring container, wherein the size distribution of the sound pressure field corresponds to the amplitude distribution of the vibration mode; the sound pressure field rotates along with the rotation of the traveling wave mode excited in the circular container; because the microspheres placed in the container bearing liquid medium move towards the sound pressure node under the action of the sound radiation force and the liquid viscous force in the sound pressure field, and the sound pressure node rotates around the circle center of the circular container due to the rotation of the sound pressure field, the microspheres can rotate around the center of the container under the action of the sound radiation force and the liquid viscous force, and the rotation control of the microspheres is realized.
The invention also discloses another piezoelectric excitation ring surface micro-control device, which comprises a container, a transducer array and a substrate;
the transducer array includes first to fourth transducers;
the first transducer, the second transducer, the third transducer, the fourth transducer and the fourth transducer are identical in structure and respectively comprise a base body, a connecting block, a fixed seat, a first piezoelectric ceramic piece and a second piezoelectric ceramic piece;
the substrate is a regular quadrangular prism and comprises two end faces and first to fourth side walls which are sequentially connected end to end, wherein the first side wall is parallel to the third side wall, and the second side wall is parallel to the fourth side wall;
the connecting block is a regular quadrangular frustum pyramid with the same shape as the end surface of one end of the base body, and the end surface of the connecting block with the larger area is correspondingly and coaxially fixedly connected with one end of the base body;
the fixing seat comprises a connecting strip and a fixing part; one end of the connecting strip is vertically and fixedly connected with the third side wall of the substrate, and the other end of the connecting strip is fixedly connected with the fixing part; the fixed part is fixedly connected with the substrate; grooves vertical to the length direction of the connecting strip are correspondingly arranged on two side surfaces of the connecting strip close to one end of the base body to form flexible hinges;
the first piezoelectric ceramic piece and the second piezoelectric ceramic piece are respectively arranged on the second side wall and the fourth side wall of the substrate, and are polarized along the thickness direction, and the polarization directions of the first piezoelectric ceramic piece and the second piezoelectric ceramic piece are opposite;
the container is annular, and an annular groove coaxial with the container is formed in the upper end face of the container and used for containing a liquid bearing medium and microspheres to be controlled; four bosses with the same end face shape as the end face with the smaller area of the second connecting part are uniformly arranged on the outer wall of the container in the circumferential direction, and the lower end face of the container is parallel to the third side wall of the base;
the end faces with smaller areas of the second connecting parts of the first transducer, the second transducer and the fourth transducer are fixedly connected with four bosses on the outer wall of the container in a one-to-one correspondence mode, so that the axes of the connecting platforms of the first transducer, the second transducer and the fourth transducer point to the center of the container; and the fixed parts of the first transducer, the second transducer and the fourth transducer are fixedly connected with the upper end face of the substrate.
As a further optimized scheme of the piezoelectric-excited micro-manipulation device in the circular ring surface, the fixing parts of the first transducer, the second transducer and the fourth transducer are strip-shaped, one end of each fixing part is vertically and fixedly connected with the corresponding connecting strip, and the fixing parts are fixedly connected with the base plate through bolts.
The invention also discloses a control method of the other piezoelectric excitation circular ring in-plane micro-control device, which comprises the following steps:
arranging the first to fourth transducers on the substrate in a clockwise sequence, and applying first to fourth simple harmonic voltage signals to the first to fourth transducers respectively;
the first simple harmonic voltage signal, the second simple harmonic voltage signal, the third simple harmonic voltage signal, the fourth simple harmonic voltage signal and the fourth simple harmonic voltage signal, the phase difference pi/2, the angular frequency is equal to a preset rotating mode frequency value omega, the phase difference is sequentially, the phase difference is pi/2, the angular frequency is equal to the preset rotating mode frequency value omega, simultaneously, the in the container is excited to generate an in space phase difference, an in the container, and the in the container, the in the plane vibration mode, the in the container, the in the mode, and the mode, and the in the mode, the container, and the in the container, and the exciting, and the in the container, and the exciting, and the in the container, and the in the container, and the in the excitation, and the container, and the in the container, and the in the container, the in order, the container, the in the excitation, the in the excitation, and the in the container, the in the excitation, the container, the excitation, the in;
under the traveling wave mode, generating a corresponding sound pressure field in a bearing liquid medium in the circular ring container, wherein the size distribution of the sound pressure field corresponds to the amplitude distribution of the vibration mode; the sound pressure field rotates along with the rotation of the traveling wave mode excited in the circular container; because the microspheres placed in the container bearing liquid medium move towards the sound pressure node under the action of the sound radiation force and the liquid viscous force in the sound pressure field, and the sound pressure node rotates around the circle center of the circular container due to the rotation of the sound pressure field, the microspheres can rotate around the center of the container under the action of the sound radiation force and the liquid viscous force, and the rotation control of the microspheres is realized.
Compared with the prior art, the invention adopting the technical scheme has the following technical effects:
1. the structure is simple, the design is easy, and the cost of the micro-control device can be reduced;
2. the piezoelectric-excited bulk acoustic wave is used as a driving source, so that nondestructive and non-contact control on large-scale (submillimeter-pole) microparticles can be realized;
3. by adopting an in-plane vibration mode, the stability of micro-particle control can be improved, and the problem of oscillation of a liquid bearing medium caused by resonance is reduced.
Drawings
FIG. 1 is a schematic diagram of one arrangement of the present invention;
FIG. 2 is a schematic diagram of a first transducer according to the present invention;
FIG. 3 is a schematic view of the structure of the holder of the present invention;
FIG. 4 is a schematic structural view of another arrangement of the present invention;
FIG. 5 is a schematic diagram of the manner in which electrical signals are applied in the present invention;
FIG. 6 is a schematic diagram of simulation of one of the modes of the traveling wave coupled out according to the present invention;
FIG. 7 is a schematic diagram of another modal simulation of the pi/2 spatial phase difference of the coupled-out traveling wave modes of the present invention;
FIG. 8 is a simulation diagram of coupled traveling wave modes in one cycle according to the present invention;
FIG. 9 is a schematic diagram of the rotation of microspheres in a circular container according to the present invention.
In the figure, 1-a ring container, 2-a third transducer, 3-a substrate, 4-a base body, 5-a second piezoceramics sheet, 2.1-a pretightening bolt, 2.2-a pretightening column, 2.3-a piezoceramics module, 2.4-a clamping seat, 2.5-a connecting table, 2.4.1-a connecting ring, 2.4.2-a flexible hinge, 2.4.3-a connecting strip and 2.4.4-a fixing part.
Detailed Description
The technical scheme of the invention is further explained in detail by combining the attached drawings:
the present invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. In the drawings, components are exaggerated for clarity.
As shown in fig. 1, the invention discloses a piezoelectric-excited micro-manipulation device in a circular ring surface, which comprises a container, a transducer array and a substrate;
the transducer array includes first to fourth transducers;
as shown in fig. 2, the first to fourth transducers have the same structure and each comprise a pre-tightening bolt, a pre-tightening column, a piezoelectric ceramic module, a clamping seat and a connecting platform;
the pre-tightening bolt comprises a nut and a stud; the pre-tightening column is a regular prism or a cylinder, and a countersunk through hole matched with the pre-tightening bolt is formed in the center of one end face of the pre-tightening column;
the connecting table comprises a first connecting part and a second connecting part, wherein the first connecting part is a regular prism or a cylinder, the second connecting part is a regular prism table or a circular table with the same shape of an end face with a larger area and an end face at one end of the first connecting part, and the second connecting part is an end face with a larger area and one end of the first connecting part which are correspondingly and coaxially fixedly connected; the other end of the first connecting part is provided with a threaded hole matched with the pre-tightening bolt;
the piezoelectric ceramic module comprises 2 groups of piezoelectric ceramic pieces, each group of piezoelectric ceramic pieces comprises n annular piezoelectric ceramic pieces, and n is a natural number more than or equal to 1;
as shown in fig. 3, the holder includes a connection ring, a connection strip, and a fixing portion; one end of the connecting strip is fixedly connected with the outer wall of the connecting circular ring and points to the circle center of the connecting circular ring, and the other end of the connecting strip is fixedly connected with the fixing part; the fixed part is fixedly connected with the substrate; grooves vertical to the length direction of the connecting strips are correspondingly arranged on two side surfaces of the connecting strips close to one end of the connecting ring to form flexible hinges;
the stud of the pre-tightening bolt sequentially penetrates through the countersunk through hole of the pre-tightening column, the 1 group of piezoelectric ceramic pieces, the connecting ring of the clamping seat and the other 1 group of piezoelectric ceramic pieces and then is in threaded connection with the threaded hole of the connecting table, and the 2 groups of piezoelectric ceramic pieces are compressed;
the 2 groups of piezoelectric ceramic pieces are symmetrically arranged about the connecting ring, the piezoelectric ceramic pieces in each group of piezoelectric ceramic pieces are polarized along the thickness direction of the piezoelectric ceramic pieces, and the polarization directions of the adjacent piezoelectric ceramic pieces in the same group of piezoelectric ceramic pieces are opposite;
the container is annular, and an annular groove coaxial with the container is formed in the upper end face of the container and used for containing a liquid bearing medium and microspheres to be controlled; four bosses with the same end face shape as the end face with smaller area of the second connecting part are uniformly arranged on the outer wall of the container in the circumferential direction;
the end faces with smaller areas of the second connecting parts of the first transducer, the second transducer and the fourth transducer are fixedly connected with four bosses on the outer wall of the container in a one-to-one correspondence mode, so that the axes of the connecting platforms of the first transducer, the second transducer and the fourth transducer point to the center of the container; and the fixed parts of the first transducer, the second transducer and the fourth transducer are fixedly connected with the upper end face of the substrate.
The pre-tightening column preferably adopts a cylinder, the first connecting part preferably adopts a regular quadrangular prism, the first connecting part preferably adopts a regular quadrangular frustum, and n preferably takes 2.
The fixing parts of the first transducer, the second transducer and the fourth transducer are strip-shaped, one end of each fixing part is vertically and fixedly connected with the corresponding connecting strip, and the fixing parts are fixedly connected with the base plate through bolts.
The invention also discloses a control method of the piezoelectric excitation circular ring in-plane micro-control device, which comprises the following steps:
as shown in fig. 5, the first to fourth transducers are arranged on the substrate in a clockwise sequence, and the first to fourth harmonic voltage signals U1, U2, U3 and U4 are applied to the first to fourth transducers, respectively;
the first to fourth simple harmonic voltage signals are alternating current harmonic signals, the voltage amplitudes are equal, the phases are sequentially different by pi/2, the angular frequency is equal to a preset rotary mode frequency value omega, and meanwhile, an in-plane vibration mode with a space phase difference of pi/2 is excited on the container, as shown in fig. 6 and 7, so that a traveling wave mode is coupled in the container; the simulation diagram of the traveling wave vibration mode in one period is shown in fig. 8;
under the traveling wave mode, generating a corresponding sound pressure field in a bearing liquid medium in the circular ring container, wherein the size distribution of the sound pressure field corresponds to the amplitude distribution of the vibration mode; the sound pressure field rotates along with the rotation of the traveling wave mode excited in the circular container; because the microspheres placed in the container carrying liquid medium move towards the sound pressure node under the action of the sound radiation force and the liquid viscous force in the sound pressure field, and the sound pressure node rotates around the circle center of the circular container due to the rotation of the sound pressure field, the microspheres can rotate around the center of the container under the action of the sound radiation force and the liquid viscous force, so that the rotation control of the microspheres is realized, as shown in fig. 9.
As shown in fig. 4, the present invention also discloses another piezoelectric-excited micro-manipulation device in a circular ring surface, which includes a container, a transducer array and a substrate;
the transducer array includes first to fourth transducers;
the first transducer, the second transducer, the third transducer, the fourth transducer and the fourth transducer are identical in structure and respectively comprise a base body, a connecting block, a fixed seat, a first piezoelectric ceramic piece and a second piezoelectric ceramic piece;
the substrate is a regular quadrangular prism and comprises two end faces and first to fourth side walls which are sequentially connected end to end, wherein the first side wall is parallel to the third side wall, and the second side wall is parallel to the fourth side wall;
the connecting block is a regular quadrangular frustum pyramid with the same shape as the end surface of one end of the base body, and the end surface of the connecting block with the larger area is correspondingly and coaxially fixedly connected with one end of the base body;
the fixing seat comprises a connecting strip and a fixing part; one end of the connecting strip is vertically and fixedly connected with the third side wall of the substrate, and the other end of the connecting strip is fixedly connected with the fixing part; the fixed part is fixedly connected with the substrate; grooves vertical to the length direction of the connecting strip are correspondingly arranged on two side surfaces of the connecting strip close to one end of the base body to form flexible hinges;
the first piezoelectric ceramic piece and the second piezoelectric ceramic piece are respectively arranged on the second side wall and the fourth side wall of the substrate, and are polarized along the thickness direction, and the polarization directions of the first piezoelectric ceramic piece and the second piezoelectric ceramic piece are opposite;
the container is annular, and an annular groove coaxial with the container is formed in the upper end face of the container and used for containing a liquid bearing medium and microspheres to be controlled; four bosses with the same end face shape as the end face with the smaller area of the second connecting part are uniformly arranged on the outer wall of the container in the circumferential direction, and the lower end face of the container is parallel to the third side wall of the base;
the end faces with smaller areas of the second connecting parts of the first transducer, the second transducer and the fourth transducer are fixedly connected with four bosses on the outer wall of the container in a one-to-one correspondence mode, so that the axes of the connecting platforms of the first transducer, the second transducer and the fourth transducer point to the center of the container; and the fixed parts of the first transducer, the second transducer and the fourth transducer are fixedly connected with the upper end face of the substrate.
The fixing parts of the first transducer, the second transducer and the fourth transducer are strip-shaped, one end of each fixing part is vertically and fixedly connected with the corresponding connecting strip, and the fixing parts are fixedly connected with the base plate through bolts.
The control method of the other piezoelectric-excited in-circle micro-manipulation device is the same as the control method of the first piezoelectric-excited in-circle micro-manipulation device, and comprises the following steps:
arranging the first to fourth transducers on the substrate in a clockwise sequence, and applying first to fourth simple harmonic voltage signals to the first to fourth transducers respectively;
the first simple harmonic voltage signal, the second simple harmonic voltage signal, the third simple harmonic voltage signal, the fourth simple harmonic voltage signal and the fourth simple harmonic voltage signal, the phase difference pi/2, the angular frequency is equal to a preset rotating mode frequency value omega, the phase difference is sequentially, the phase difference is pi/2, the angular frequency is equal to the preset rotating mode frequency value omega, simultaneously, the in the container is excited to generate an in space phase difference, an in the container, and the in the container, the in the plane vibration mode, the in the container, the in the mode, and the mode, and the in the mode, the container, and the in the container, and the exciting, and the in the container, and the exciting, and the in the container, and the in the container, and the in the excitation, and the container, and the in the container, and the in the container, the in order, the container, the in the excitation, the in the excitation, and the in the container, the in the excitation, the container, the excitation, the in;
under the traveling wave mode, generating a corresponding sound pressure field in a bearing liquid medium in the circular ring container, wherein the size distribution of the sound pressure field corresponds to the amplitude distribution of the vibration mode; the sound pressure field rotates along with the rotation of the traveling wave mode excited in the circular container; because the microspheres placed in the container bearing liquid medium move towards the sound pressure node under the action of the sound radiation force and the liquid viscous force in the sound pressure field, and the sound pressure node rotates around the circle center of the circular container due to the rotation of the sound pressure field, the microspheres can rotate around the center of the container under the action of the sound radiation force and the liquid viscous force, and the rotation control of the microspheres is realized.
It will be understood by those skilled in the art that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the prior art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
The above-mentioned embodiments, objects, technical solutions and advantages of the present invention are further described in detail, it should be understood that the above-mentioned embodiments are only illustrative of the present invention and are not intended to limit the present invention, and any modifications, equivalents, improvements and the like made within the spirit and principle of the present invention should be included in the protection scope of the present invention.