Programmable surface acoustic wave device and regulation and control method and preparation method thereof

Abstract

The invention relates to the technical field of surface acoustic waves, in particular to a programmable surface acoustic wave device and a regulation and control method and a preparation method thereof. The surface wave device comprises a control circuit and a plurality of interdigital electrode units distributed in an array. The control circuit comprises a signal source and a plurality of control switches, and the control switches are in one-to-one correspondence with the interdigital electrode units; each interdigital electrode unit is connected with the signal source through the control switch, and the control switch is used for controlling the interdigital electrode units to be communicated with the signal source in the forward direction or in the reverse direction and used for generating single surface acoustic waves with the phase difference being pi; when a plurality of interdigital electrode units distributed in an array are communicated with the signal source in the forward direction or the reverse direction, the single surface acoustic waves generated by the interdigital electrode units are superposed to form the surface acoustic wave with an expected waveform. According to the invention, the limitation that only a single waveform can be generated under a traditional surface acoustic wave single electrode structure can be broken through, and the surface acoustic waves with various waveforms can be generated through programming control of the control switch.

Description

Technical Field

[0001] The present invention relates to the field of surface acoustic wave technology, and in particular to a programmable surface acoustic wave device and a control method and a preparation method thereof. Background Art

[0002] Surface acoustic wave is a mechanical wave that propagates along the surface of a solid. Traditional surface acoustic wave devices are composed of piezoelectric materials and interdigital electrodes. The electrical energy applied to the interdigital electrodes can be converted into mechanical energy on the piezoelectric material according to the inverse piezoelectric effect, generating surface acoustic waves. Compared with body waves, surface acoustic waves propagate along the surface, reducing the energy loss during the propagation process, making them exhibit excellent performance in long-distance transmission. Therefore, surface acoustic waves are widely used in wireless communication systems, such as surface acoustic wave filters and surface acoustic wave antennas. Their excellent propagation properties give them unique advantages in spectrum management and communication system design. In addition, surface acoustic waves mainly propagate along the surface and are less sensitive to air propagation or other noise sources, which improves the anti-interference ability of the system. This advantage is also used in sensing applications. Surface acoustic waves can be used to manufacture highly sensitive sensors for detecting parameters such as pressure, temperature, and liquid concentration. Their flexible controllability makes them suitable for a variety of environments and conditions. Surface acoustic waves can also be used for acoustic signal processing. By designing and controlling the surface structure, the propagation characteristics of surface acoustic waves, including frequency, phase velocity and wavelength, can be adjusted, and highly programmable control of sound waves can be achieved, realizing functions such as sound wave filtering, modulation and demodulation.

[0003] The interdigitated electrodes of traditional surface acoustic wave devices are of a single structure, that is, once the size of the electrode structure is determined, the characteristic parameters of the surface acoustic wave including frequency, wavelength and phase are also fixed on the same piezoelectric substrate. At present, there are roughly the following ways to achieve surface acoustic wave control.

[0004] The frequency of surface acoustic waves is mainly controlled by changing the width of the interdigital electrodes. The interdigital electrodes with gradually varying widths are prepared on a piezoelectric material substrate using photolithography and metal evaporation technology, which can achieve multi-frequency response and control of surface acoustic waves. However, a single electrode structure cannot achieve waveform control, and still cannot achieve surface acoustic waves with complex waveforms.

[0005] Another method is to design interdigital electrodes with specific shapes, such as bending and tilting, to generate surface acoustic waves with complex waveforms, such as tilting, focusing and diverging of acoustic waves. However, once the interdigital electrodes are prepared, they can only generate surface acoustic waves with a single waveform, and cannot generate surface acoustic waves with multiple waveforms.

[0006] The control of the surface acoustic wave by the above-mentioned surface acoustic wave devices is all based on the interdigital electrodes with fixed structures, and thus can only generate surface acoustic waves of a single waveform, and cannot realize the switching of the surface acoustic wave waveform. Summary of the invention

[0007] 1. Technical issues to be resolved

[0008] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides a programmable surface acoustic wave device and its control method and preparation method, which solve the technical problem that the existing surface acoustic wave device has a fixed interdigital electrode structure and can only generate surface acoustic waves of a single waveform.

[0009] (II) Technical solution

[0010] In order to achieve the above object, the main technical solutions adopted by the present invention include:

[0011] In a first aspect, an embodiment of the present invention provides a programmable surface acoustic wave device, comprising a control circuit and a plurality of array-distributed interdigital electrode units;

[0012] The control circuit includes a signal source and a plurality of control switches, and the control switches correspond to the interdigital electrode units one by one;

[0013] Each of the interdigital electrode units is connected to the signal source via the control switch, and the control switch is used to control the interdigital electrode unit to be connected to the signal source in a forward direction or a reverse direction, so as to generate a single surface acoustic wave with a phase difference of π;

[0014] When a plurality of array-distributed interdigital electrode units are connected to a signal source in a forward direction or in a reverse direction, the single surface acoustic waves generated by each interdigital electrode unit are superimposed to form a surface acoustic wave of an expected waveform.

[0015] Optionally, the control switch comprises a first input terminal, a second input terminal and an output terminal; the first input terminal is connected to a signal source in a forward direction, the second input terminal is connected to a signal source in a reverse direction, and the output terminal is connected to the interdigital electrode unit in a communication manner;

[0016] When the control circuit controls the interdigital electrode unit to be connected to the signal source in a forward direction, the control switch connects the first input end to the output end;

[0017] When the control circuit controls the interdigital electrode unit to be connected to the signal source in reverse, the control switch connects the second input end to the output end.

[0018] Optionally, the control switch is a multi-pole multi-throw switch or a relay.

[0019] Optionally, the plurality of interdigital electrode units are perpendicular to the same straight line, and the surface acoustic wave output end of each of the interdigital electrode units faces the same direction;

[0020] The number of interdigital electrode units is not less than 10;

[0021] The number of fingers of the interdigital electrode unit is not less than 15.

[0022] Optionally, when the programmable surface acoustic wave device is used for particle manipulation, the plurality of interdigital electrode units are perpendicular to the same straight line and are equidistantly distributed from each other, and the surface acoustic wave output end of each interdigital electrode unit faces the same direction and is located on the same straight line;

[0023] The number of interdigital electrode units ranges from [20,60];

[0024] The number of fingers of the interdigital electrode unit ranges from [16,24];

[0025] The finger width of the interdigitated electrode unit ranges from [100 μm, 150 μm];

[0026] The interdigital electrode finger spacing ranges from [200 μm, 300 μm];

[0027] The width of the interdigitated electrode unit ranges from [176 μm, 264 μm];

[0028] The spacing between the interdigitated electrode units ranges from [8μm, 12μm].

[0029] In a second aspect, an embodiment of the present invention provides a control method for a surface acoustic wave device, wherein the surface acoustic wave device is the surface acoustic wave device according to the first aspect, and the control method comprises:

[0030] Controlling the control switch so that the interdigital electrode unit is connected to the signal source in a forward direction or a reverse direction to form a surface acoustic wave of a desired waveform; or,

[0031] The control switch is controlled to change the waveform of the generated surface acoustic wave in real time by changing the connection state between the interdigital electrode unit and the signal source.

[0032] Optionally, the surface acoustic wave device is the surface acoustic wave device according to claim 5, and the control method comprises:

[0033] Set the control state of the control switch controlling an interdigital electrode unit to be connected to the signal source in the forward direction to 1, and the control state of the control switch controlling an interdigital electrode unit to be connected to the signal source in the reverse direction to 0;

[0034] When the surface acoustic wave of the expected waveform is an Airy beam, the control states of the control switches corresponding to the interdigital electrode units are, in order of adjacent positions, 1100110011000111000111000111100001111111.

[0035] Optionally, the surface acoustic wave device is the surface acoustic wave device according to claim 5, and the number of the surface acoustic wave devices is two, and the surface acoustic wave output ends of the two surface acoustic wave devices are arranged in opposite directions;

[0036] Set the control state of the control switch controlling an interdigital electrode unit to be connected to the signal source in the forward direction to 1, and the control state of the control switch controlling an interdigital electrode unit to be connected to the signal source in the reverse direction to 0;

[0037] When the surface acoustic wave of the expected waveform is a focused surface acoustic wave, the control states of the control switches corresponding to the interdigital electrode units of each surface acoustic wave device are, in order of adjacent positions, 00110001110000111111111111100001110001100.

[0038] Optionally, the control method further comprises: controlling the control state of a control switch in the surface acoustic wave device in real time to adjust the position of the focus of the focused surface acoustic wave in real time.

[0039] In a third aspect, an embodiment of the present invention provides a method for preparing a surface acoustic wave device, which is used to prepare the programmable surface acoustic wave device according to the first aspect, comprising:

[0040] S1. Clean a 128° YX-cut, 4-inch lithium niobate wafer, evenly spin-coat it with photoresist, and bake it at 100°C for 3 minutes to use as a substrate;

[0041] S2, using a laser direct writer to expose the electrode pattern of the preset array-distributed interdigitated electrode units on the substrate, followed by development for 30 seconds;

[0042] S3, sequentially coating a 3nm Cr adhesion layer and a 50nm Au electrode layer on the substrate with the existing electrode pattern;

[0043] S4, soaking the substrate in acetone for 2 hours, and then washing it in an ultrasonic cleaner to remove excess photoresist and metal layer, thereby obtaining array-distributed interdigitated electrode units;

[0044] S5, attaching the embossing glue to the left electrode pin and the right electrode pin of the interdigital electrode unit, aligning the wiring with the left electrode pin or the right electrode pin and performing preliminary compaction, and then using a compaction machine to compact;

[0045] S6. Connect the wiring to a control circuit to obtain the programmable surface acoustic wave device.

[0046] (III) Beneficial effects

[0047] The programmable surface acoustic wave device proposed in the present invention includes a control circuit and a plurality of array-distributed interdigitated electrode units; the control circuit includes a signal source and a plurality of control switches, and the control switches correspond to the interdigitated electrode units one by one; each of the interdigitated electrode units is connected to the signal source via the control switch, and the control switch is used to control the interdigitated electrode unit to be connected to the signal source in a forward direction or in a reverse direction, so as to generate a monomer surface acoustic wave with a phase difference of π; when the plurality of array-distributed interdigitated electrode units are connected to the signal source in a forward direction or in a reverse direction, the monomer surface acoustic wave generated by each interdigitated electrode unit is superimposed to form a surface acoustic wave with an expected waveform.

[0048] Based on the above array-distributed interdigital electrode units and the control switches corresponding to each interdigital electrode unit, the control circuit can generate a single surface acoustic wave with a phase change of π by controlling each interdigital electrode unit to be connected forward or reversely, and then control the expected multi-waveform surface acoustic wave by individually controlling the phase of the single surface acoustic wave generated by each interdigital electrode unit, thereby breaking through the limitation that only a single waveform can be generated under the single electrode structure of the traditional surface acoustic wave, and can generate surface acoustic waves of multiple waveforms on the fixed electrode structure by programming the control switch, realizing multi-waveform control of the surface acoustic wave, with the advantages of high control freedom, low attenuation, simple preparation, etc. Combined with the mature surface acoustic wave device manufacturing process, the programmable surface acoustic wave device provided by the present invention will have greater application prospects in the fields of communication, sensing and biomedicine. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 A schematic structural diagram of a surface acoustic wave device provided in an embodiment;

[0050] Figure 2 A schematic diagram of switching the connectivity state of an interdigital electrode unit in an embodiment;

[0051] Figure 3 A schematic diagram of an array distribution mode of interdigitated electrode units in an embodiment;

[0052] Figure 4 Schematic diagram of another array distribution mode of interdigitated electrode units in an embodiment

[0053] Figure 5 A schematic diagram of another array distribution mode of interdigitated electrode units in an embodiment;

[0054] Figure 6 A detailed schematic diagram of an interdigitated electrode array in an embodiment;

[0055] Figure 7 Schematic diagram of simulation results and experimental results of the Airy acoustic beam in the embodiment;

[0056] Figure 8 A schematic diagram of the structure of a surface acoustic wave device for focusing surface acoustic waves in an embodiment and a schematic diagram of corresponding simulation results and experimental results;

[0057] Fig. 9 Schematic diagram of the device structure for manipulating particles in the embodiment and the corresponding experimental results.

[0058] [Description of Reference Numerals]

[0059] 1. Interdigitated electrode unit; 2. Fingers; 3. Connecting wires; 4. Pins; 5. Metal connection area. DETAILED DESCRIPTION

[0060] In order to better explain the present invention, so as to facilitate understanding, exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the accompanying drawings, it should be understood that the present invention can be implemented in various forms and should not be limited by the embodiments set forth herein. On the contrary, these embodiments are provided in order to enable a clearer and more thorough understanding of the present invention, and to be able to fully convey the scope of the present invention to those skilled in the art.

[0061] Embodiment 1

[0062] An embodiment of the present invention provides a programmable surface acoustic wave device, comprising a control circuit and a plurality of interdigital electrode units distributed in an array, wherein each of the interdigital electrode units comprises a left electrode and a right electrode.

[0063] The control circuit includes a signal source and a plurality of control switches, wherein the control switches correspond to the interdigital electrode units one by one. Specifically, the control switches are multi-pole multi-throw switches or relays.

[0064] Each of the interdigital electrode units is connected to the signal source via the control switch, and the control switch is used to control the interdigital electrode unit to be connected to the signal source in a forward direction or a reverse direction, so as to generate a single surface acoustic wave with a phase difference of π.

[0065] When a plurality of array-distributed interdigital electrode units are connected to a signal source in a forward direction or in a reverse direction, the single surface acoustic waves generated by each interdigital electrode unit are superimposed to form a surface acoustic wave of an expected waveform.

[0066] Based on the above array-distributed interdigital electrode units and the control switches corresponding to each interdigital electrode unit, the control circuit can generate a single surface acoustic wave with a phase change of π by controlling each interdigital electrode unit to be connected forward or reversely, and then control the expected multi-waveform surface acoustic wave by individually controlling the phase of the single surface acoustic wave generated by each interdigital electrode unit, thereby breaking through the limitation that only a single waveform can be generated under the single electrode structure of the traditional surface acoustic wave, and can generate surface acoustic waves of multiple waveforms on the fixed electrode structure by programming the control switch, realizing multi-waveform control of the surface acoustic wave, with the advantages of high control freedom, low attenuation, simple preparation, etc. Combined with the mature surface acoustic wave device manufacturing process, the programmable surface acoustic wave device provided by the present invention will have greater application prospects in the fields of communication, sensing and biomedicine.

[0067] In a specific implementation of this embodiment, the signal source includes a signal terminal and a ground terminal.

[0068] like Figure 1 and Figure 7 As shown, a plurality of interdigitated electrode units 1 are distributed in an array to form an interdigitated electrode array, each of the interdigitated electrode units 1 comprises a left electrode and a right electrode, the left electrode and the right electrode respectively comprise a plurality of fingers 2 and connecting wires 3 connecting the corresponding fingers, the fingers 2 of the left electrode and the fingers 2 of the right electrode are staggered and inserted into each other, pins 4 are respectively arranged at the ends of the connecting wires 3 of the left electrode and the right electrode to facilitate connection with the control switch, and a gradually expanding metal connecting area 5 can be arranged at the connection from the connecting wire 3 to the pin 4 to ensure the reliability of the connection between the two.

[0069] like Figure 2 As shown, the control switch includes a first input terminal, second input terminals E and F, and output terminals C and D, the first input terminal includes terminal A and terminal B, the second input terminal includes terminal E and terminal F, the output terminal includes terminal C and terminal D, and the positions of terminals A, C, and E are correspondingly located on the same straight line, and the positions of terminals B, D, and F are correspondingly located on the same straight line, and the output terminal is communicatively connected with the interdigital electrode unit. When the output terminal is connected to the first input terminal, terminal C contacts terminal A, and terminal D contacts terminal B, so that the interdigital electrode unit is connected to the signal source in the forward direction; when the output terminal is connected to the second input terminal, terminal C contacts terminal E, and terminal D contacts terminal F, so that the interdigital electrode unit is connected to the signal source in the reverse direction.

[0070] Specifically, the signal source includes a signal terminal (Floating) and a ground terminal (Ground); the interdigitated electrode unit includes a left electrode and a right electrode; the A terminal of the first input terminal is connected to the signal terminal of the signal source, the B terminal of the first input terminal is connected to the ground terminal of the signal source, the E terminal of the second input terminal is connected to the signal terminal of the signal source, the F terminal of the second input terminal is connected to the ground terminal of the signal source, the C terminal of the output terminal is connected to the left electrode of the interdigitated electrode unit, and the D terminal of the output terminal is connected to the right electrode of the interdigitated electrode unit.

[0071] When the control circuit controls the interdigital electrode unit to be connected to the signal source in a forward direction, the control switch connects the first input end to the output end. When the control circuit controls the interdigital electrode unit to be connected to the signal source in a reverse direction, the control switch connects the second input end to the output end.

[0072] The control circuit further includes a controller, which is used to encode the connection state of the control switch to control the corresponding interdigital electrode unit to be connected to the signal source in the forward direction or in the reverse direction. The connection state includes forward connection and reverse connection.

[0073] In another specific implementation of this embodiment, the number, size and array distribution of the above-mentioned interdigitated electrode units can be further designed according to their specific application scenarios.

[0074] Specifically, Figure 1 As shown, the plurality of interdigital electrode units may be perpendicular to the same straight line and distributed equidistantly from each other, and the surface acoustic wave output end of each of the interdigital electrode units may face the same direction and be located in the same straight line; or Figure 3 As shown, multiple interdigital electrode units can be perpendicular to the same straight line and equidistantly distributed from each other, and the surface acoustic wave output end of each interdigital electrode unit is cross-distributed front and back, so that the output end of the interdigital electrode array as a whole is sawtooth-shaped; or Figure 4 As shown, Figure 1 The single-row interdigital electrode array shown is replicated into multiple rows, and the surface acoustic wave output ends of each row of interdigital electrodes are in the same longitudinal position as the surface acoustic wave output ends of the interdigital electrodes corresponding to other rows, so that the multiple interdigital electrode units are distributed in a rectangular array; Figure 5 As shown, a plurality of interdigital electrode units may be evenly distributed along the same arc, and the surface acoustic wave output end of each of the interdigital electrode units faces the focus of the arc.

[0075] Preferably, the plurality of interdigital electrode units are perpendicular to the same straight line, and the surface acoustic wave output end of each of the interdigital electrode units faces the same direction; the number of the interdigital electrode units is not less than 10; and the number of fingers of the interdigital electrode unit is not less than 15.

[0076] More preferably, when the programmable surface acoustic wave device is used for particle manipulation, the plurality of interdigital electrode units are perpendicular to the same straight line and are equidistant from each other, the surface acoustic wave output end of each interdigital electrode unit faces the same direction and is located in the same straight line, and the parameters of the interdigital electrode array are as follows:

[0077] The number of the interdigital electrode units is in the range of [20, 60];

[0078] The number of fingers of the interdigital electrode unit is in the range of [16, 24];

[0079] The finger width of the interdigitated electrode unit ranges from [100 μm, 150 μm];

[0080] The finger spacing of the interdigitated electrodes ranges from [200 μm, 300 μm];

[0081] The width of the interdigital electrode unit ranges from [176 μm, 264 μm];

[0082] The spacing between the interdigitated electrode units ranges from [8μm, 12μm].

[0083] Specifically, Figure 6 As shown, the definitions of the above parameters are explained as follows: the number of fingers of the interdigitated electrode unit refers to the sum of the number of fingers of the left electrode and the right electrode in one interdigitated electrode unit; the finger width of the interdigitated electrode unit refers to the width of a finger in the direction of the center line of the interdigitated electrode unit; the finger spacing of the interdigitated electrodes refers to the distance between the upper edges of two adjacent fingers, or the distance between the lower edges of two adjacent fingers; the width of the interdigitated electrode unit refers to the distance between the connecting line of the left electrode and the connecting line of the right electrode of the interdigitated electrode unit; the spacing of the interdigitated electrode units refers to the spacing between the right electrode connecting line of the interdigitated electrode unit on the left and the left electrode connecting line of the interdigitated electrode unit on the right for two adjacent interdigitated electrode units.

[0084] Optimally, in order to balance the size and control accuracy of the surface acoustic wave device, the parameters of a preferred surface acoustic wave device provided in this embodiment are as follows:

[0085] The number of interdigital electrode units is 40;

[0086] The number of fingers of the interdigitated electrode unit is 20;

[0087] The finger width of the interdigitated electrode unit is 125 μm;

[0088] The interdigital electrode has a finger spacing of 250 μm;

[0089] The width of the interdigitated electrode unit is 220 μm;

[0090] The pitch of the interdigitated electrode units is 10 μm.

[0091] Embodiment 2

[0092] Based on the programmable surface acoustic wave device provided in the first embodiment, this embodiment specifically describes its control method.

[0093] An embodiment of the present invention provides a control method for a surface acoustic wave device, wherein the surface acoustic wave device is the surface acoustic wave device provided in Embodiment 1, and the control method includes:

[0094] Control the control switch so that the interdigital electrode unit is connected to the signal source in a forward direction or a reverse direction to form an acoustic surface wave of an expected waveform; or control the control switch to change the waveform of the generated acoustic surface wave in real time by changing the connection state between the interdigital electrode unit and the signal source.

[0095] Based on the above control method, when the number, size and array distribution of the interdigital electrode units are different, the encoding method corresponding to the control switch is also different.

[0096] In a specific embodiment, when the programmable surface acoustic wave device is used for particle manipulation, this embodiment takes the optimal surface acoustic wave device provided in Example 1 as an example, that is, it is configured as follows: 40 interdigitated electrode units are perpendicular to the same straight line and are equidistant from each other, the surface acoustic wave output end of each of the interdigitated electrode units is oriented in the same direction and is located in the same straight line, and the number of fingers of the interdigitated electrode unit is 20, the finger width of the interdigitated electrode unit is 125 μm, the finger spacing of the interdigitated electrode is 250 μm, the width of the interdigitated electrode unit is 220 μm, and the spacing between two adjacent interdigitated electrode units is 10 μm; and the control circuit selects a 7.98 MHz, 20 Vpp sinusoidal wave voltage signal generator as a signal source, and its control method is specifically described and experimentally verified.

[0097] The control state of the control switch controlling an interdigital electrode unit to be connected to the signal source in the forward direction is set to 1, and the control state of the control switch controlling an interdigital electrode unit to be connected to the signal source in the reverse direction is set to 0.

[0098] When the surface acoustic wave of the expected waveform is an Airy beam, the control states of the control switches corresponding to the interdigital electrode units are, in order of adjacent positions (from left to right), 1100110011000111000111000111100001111111. The simulation results of the Airy beam under the control state coding are shown in FIG. Figure 7 As shown in (a), a Doppler laser vibrometer is used to scan an area of ​​2.5 cm × 5 cm in the direction of sound wave propagation. The waveform obtained is as follows: Figure 7 (b) shows that the results are consistent with the simulation results.

[0099] Of course, the above control state encoding can be switched to the reverse order to obtain a mirrored Airy acoustic beam; that is, the control states of the control switches corresponding to the interdigital electrode units are set in the order of adjacent positions (from left to right): 1111111000011110001110001110001100110011, and a mirrored Airy acoustic beam can be obtained. The simulation results of the Airy acoustic beam under the control state encoding are as follows: Figure 7 As shown in (c), a Doppler laser vibrometer is used to scan an area of ​​2.5 cm × 5 cm in the direction of sound wave propagation. The waveform obtained is as follows: Figure 7 That is, the control method provided in this embodiment can change the main lobe position and bending direction of the Airy acoustic beam by changing the coding order of the control state.

[0100] When the SAW device with the above parameters is applied to particle manipulation, it can be realized by using two SAW devices arranged opposite to each other to generate a focused SAW. Figure 8 As shown in (a), the surface acoustic wave output ends of the two surface acoustic wave devices are arranged to face each other, and the distance between the surface acoustic wave output ends of the two surface acoustic wave devices is 2 cm.

[0101] The control state of the control switch controlling an interdigital electrode unit to be connected to the signal source in the forward direction is set to 1, and the control state of the control switch controlling an interdigital electrode unit to be connected to the signal source in the reverse direction is set to 0.

[0102] When the surface acoustic wave of the expected waveform is a focused surface acoustic wave, the control states of the control switches corresponding to the interdigital electrode units of each surface acoustic wave device are, in the order of adjacent positions, 00110001110000111111111111100001110001100. A Doppler laser vibrometer is used to scan an area of ​​2.5 cm×5 cm in the direction of acoustic wave propagation. The waveform obtained is as follows: Figure 8 (b) as shown.

[0103] Furthermore, the surface acoustic wave device can also adjust the position of the focus of the focused surface acoustic wave in real time: the control state of the control switch in the surface acoustic wave device is controlled in real time to adjust the position of the focus of the focused surface acoustic wave in real time. Specifically, when the coding of the interdigital electrode arrays on both sides (from top to bottom) is changed to "0001110000111111111111000011100011001100", the focus of the surface acoustic wave can be controlled to move upward by 0.88mm, and a Doppler laser vibrometer is used to scan an area of ​​2.5cm×5cm in the direction of sound wave propagation, and the waveform obtained is as follows: Figure 8(c) As shown; when the codes of the interdigital electrode arrays on both sides (from top to bottom) are changed to "00110011000111000011111111111110000111000", the focus of the surface acoustic wave is translated downward by 0.96 mm, and a Doppler laser vibrometer is used to scan an area of ​​2.5 cm × 5 cm in the direction of acoustic wave propagation. The waveform obtained is as follows Figure 8 When the left interdigital electrode array is coded (from top to bottom) as “11001100011100001111111110000111000110011” and the right interdigital electrode array is coded (from top to bottom) as “11000111000011111111111111111000011100011”, the focus of the surface acoustic wave can be controlled to translate to the left, and a Doppler laser vibrometer is used to scan an area of ​​2.5 cm × 5 cm in the direction of acoustic wave propagation. The waveform obtained is as follows: Figure 8 When the left interdigital electrode array is coded (from top to bottom) as “1100011100001111111111111111000011100011” and the right interdigital electrode array is coded (from top to bottom) as “1100110001110000111111110000111000110011”, the focus of the surface acoustic wave can be controlled to translate to the right, and a Doppler laser vibrometer is used to scan an area of ​​2.5 cm × 5 cm in the direction of acoustic wave propagation. The waveform obtained is as follows Figure 8 (f) as shown.

[0104] It can be seen from the above operations and experimental verification results that by switching the connectivity state corresponding to each interdigitated electrode unit, the focal position of the focused surface acoustic wave can be finely controlled, thereby achieving real-time fine control of the generated surface acoustic wave.

[0105] Based on the above-mentioned method for controlling the focus of the focused surface acoustic wave, the specific method for controlling the particles is as follows:

[0106] like Fig. 9As shown in (a), the above-mentioned programmable control device capable of generating focused surface acoustic waves is used, and the distance between the surface acoustic wave output ends of the two surface acoustic wave devices is 1.6 cm, and a water storage cavity is made in the middle area of ​​the two surface acoustic wave devices using tape. The size of the tape is 1.8 cm × 3 cm, and the hollow area in the middle of the tape is 1.6 cm × 2 cm. The device is placed in a UV light cleaning machine for surface hydrophilic treatment for 20 minutes. Subsequently, a pipette gun is used to evenly spread a water film of about 150 μm in the water storage cavity, and a polypropylene ball with a diameter of about 250 μm is placed. The signal source (signal generator) is connected to the power amplifier, and a sinusoidal AC signal is set with a frequency of 7.98 MHz and an amplitude of 500 mVpp. After the signal source passes through the power amplifier to amplify the voltage 100 times, it is connected to the surface acoustic wave device through the control switch, and the controller controls the control state of the control switch. By using the above-mentioned method for controlling the focus of the focused surface acoustic wave, the focus position of the focused surface acoustic wave is adjusted by coding. The acoustic radiation force at the high field intensity of the focused surface acoustic wave will cause the water to flow from the high sound pressure area to the low sound pressure area, thereby promoting the movement of the ball, and realizing the control of the particles by the programmable surface acoustic wave, such as Fig. 9 As shown in (b), the black dotted line is the trajectory of the particle.

[0107] Embodiment 3

[0108] The embodiment of the present invention provides a method for preparing a surface acoustic wave device, which is used to prepare the programmable surface acoustic wave device described in the first embodiment, and includes steps S1 to S6:

[0109] S1. Clean a 128° YX-cut, 4-inch lithium niobate wafer, evenly spin-coat it with RZJ-304-10 positive photoresist at a speed of 3000 rpm for 30 seconds, and bake it at 100°C for 3 minutes to use as a substrate.

[0110] S2. Using a laser direct writer, the electrode pattern of the interdigitated electrode units with a preset array distribution is exposed on the substrate, followed by development for 30 seconds.

[0111] S3. Use electron beam evaporation technology to sequentially deposit a 3 nm Cr adhesion layer and a 50 nm Au electrode layer on the substrate with the existing electrode pattern.

[0112] S4. Soak the substrate in acetone for 2 hours, and then put it in an ultrasonic cleaner and clean it for 20 minutes at a power of 60W to remove excess photoresist and metal layer, thereby obtaining array-distributed interdigitated electrode units.

[0113] S5. Attach the embossed glue to the left electrode pin and the right electrode pin of the interdigitated electrode unit, align the wiring with the left electrode pin or the right electrode pin and perform preliminary compaction, then place the connection between the pin and the wiring in a compaction machine and apply 167MPa and 140°C for compaction.

[0114] S6. Connect the wiring to a control circuit to obtain the programmable surface acoustic wave device.

[0115] The present invention is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems) and computer program products according to the embodiments of the present invention. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions.

[0116] It should be noted that in the claims, any reference numerals placed between brackets shall not be construed as limiting the claims. The word "comprising" does not exclude the presence of components or steps not listed in the claims. The word "a" or "an" preceding a component does not exclude the presence of a plurality of such components. The invention may be implemented by means of hardware comprising several different components and by means of a suitably programmed computer. In the claims enumerating several means, several of these means may be embodied by the same hardware. The use of the words first, second, third, etc., is for convenience of expression only and does not indicate any order. These words may be understood as part of the component name.

[0117] In addition, it should be noted that, in the description of this specification, the description of the terms "one embodiment", "some embodiments", "embodiment", "example", "specific example" or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

[0118] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments after knowing the basic creative concept. Therefore, the claims should be interpreted as including the preferred embodiments and all changes and modifications falling within the scope of the present invention.

[0119] Obviously, those skilled in the art can make various modifications and variations to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention should also include these modifications and variations.

Claims

1. A programmable surface acoustic wave device, characterized in that: It includes a control circuit and a plurality of interdigital electrode units distributed in an array; The control circuit includes a signal source and a plurality of control switches, and the control switches correspond to the interdigital electrode units one by one; Each of the interdigital electrode units is connected to the signal source via the control switch, and the control switch is used to control the interdigital electrode unit to be connected to the signal source in a forward direction or a reverse direction, so as to generate a single surface acoustic wave with a phase difference of π; When a plurality of array-distributed interdigital electrode units are connected to a signal source in a forward direction or in a reverse direction, the single surface acoustic waves generated by each interdigital electrode unit are superimposed to form a surface acoustic wave of an expected waveform.

2. The programmable surface acoustic wave device according to claim 1, characterized in that: The control switch comprises a first input terminal, a second input terminal and an output terminal; the first input terminal is connected to a signal source in a forward direction, the second input terminal is connected to a signal source in a reverse direction, and the output terminal is connected to the interdigital electrode unit in a communication manner; When the control circuit controls the interdigital electrode unit to be connected to the signal source in a forward direction, the control switch connects the first input end to the output end; When the control circuit controls the interdigital electrode unit to be connected to the signal source in reverse, the control switch connects the second input end to the output end.

3. The programmable surface acoustic wave device according to claim 2, characterized in that: The control switch is a multi-pole multi-throw switch or a relay.

4. The programmable surface acoustic wave device according to claim 2, characterized in that: The plurality of interdigital electrode units are perpendicular to the same straight line, and the surface acoustic wave output end of each of the interdigital electrode units faces the same direction; The number of interdigital electrode units is not less than 10; The number of fingers of the interdigital electrode unit is not less than 15.

5. The programmable surface acoustic wave device according to claim 4, characterized in that: When the programmable surface acoustic wave device is used for particle manipulation, the plurality of interdigital electrode units are perpendicular to the same straight line and are equidistantly distributed from each other, and the surface acoustic wave output end of each interdigital electrode unit faces the same direction and is located on the same straight line; The number of interdigital electrode units ranges from [20,60]; The number of fingers of the interdigital electrode unit ranges from [16,24]; The finger width of the interdigitated electrode unit ranges from [100 μm, 150 μm]; The interdigital electrode spacing ranges from [200 μm, 300 μm]; The width of the interdigitated electrode unit ranges from [176 μm, 264 μm]; The spacing between the interdigitated electrode units ranges from [8μm, 12μm].

6. A method for controlling a surface acoustic wave device, characterized in that: The surface acoustic wave device is the surface acoustic wave device according to any one of claims 1 to 5, and the control method comprises: Controlling the control switch so that the interdigital electrode unit is connected to the signal source in a forward direction or a reverse direction to form a surface acoustic wave of a desired waveform; or, The control switch is controlled to change the waveform of the generated surface acoustic wave in real time by changing the connection state between the interdigital electrode unit and the signal source.

7. The control method according to claim 6, characterized in that: The surface acoustic wave device is the surface acoustic wave device according to claim 5, and the control method comprises: Set the control state of the control switch controlling an interdigital electrode unit to be connected to the signal source in the forward direction to 1, and the control state of the control switch controlling an interdigital electrode unit to be connected to the signal source in the reverse direction to 0; When the surface acoustic wave of the expected waveform is an Airy beam, the control states of the control switches corresponding to the interdigital electrode units are, in order of adjacent positions, 1100110011000111000111000111100001111111.

8. The control method according to claim 6, characterized in that: The surface acoustic wave device is the surface acoustic wave device according to claim 5, and the number of the surface acoustic wave devices is two, and the surface acoustic wave output ends of the two surface acoustic wave devices are arranged in opposite directions; Set the control state of the control switch controlling an interdigital electrode unit to be connected to the signal source in the forward direction to 1, and the control state of the control switch controlling an interdigital electrode unit to be connected to the signal source in the reverse direction to 0; When the surface acoustic wave of the expected waveform is a focused surface acoustic wave, the control states of the control switches corresponding to the interdigital electrode units of each surface acoustic wave device are, in order of adjacent positions, 00110001110000111111111111100001110001100.

9. The control method according to claim 8, characterized in that: The control method further includes: controlling the control state of a control switch in the surface acoustic wave device in real time to adjust the position of the focus of the focused surface acoustic wave in real time.

10. A method for preparing a surface acoustic wave device, used for preparing the programmable surface acoustic wave device according to claims 1 to 5, characterized in that: include: S1. Clean a 128° YX-cut, 4-inch lithium niobate wafer, evenly spin-coat it with photoresist, and bake it at 100°C for 3 minutes to use as a substrate; S2, using a laser direct writer to expose the electrode pattern of the preset array-distributed interdigitated electrode units on the substrate, followed by development for 30 seconds; S3, sequentially coating a 3nm Cr adhesion layer and a 50nm Au electrode layer on the substrate with the existing electrode pattern; S4, soaking the substrate in acetone for 2 hours, and then washing it in an ultrasonic cleaner to remove excess photoresist and metal layer, thereby obtaining array-distributed interdigitated electrode units; S5, attaching the embossing glue to the left electrode pin and the right electrode pin of the interdigital electrode unit, aligning the wiring with the left electrode pin or the right electrode pin and performing preliminary compaction, and then using a compaction machine to compact; S6. Connect the wiring to a control circuit to obtain the programmable surface acoustic wave device.

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