CN116619908A - Droplet jetting device with sector resonant cavity focusing sound wave - Google Patents

Abstract

The utility model discloses a droplet jetting device of sector resonant cavity focusing sound wave, which comprises an ultrasonic generating device, a liquid supply device, a nozzle, a substrate and a resonant cavity component, wherein the resonant cavity component comprises a resonant cavity, a sound wave entering channel and an aperture; the resonant cavity is provided with at least two layers of fan-shaped cavities, each layer of fan-shaped cavity is at least communicated with one sound wave entering channel, the sound wave entering channel is in an arc shape coaxial with the fan-shaped cavity, the radiuses of the fan-shaped cavity and the arc-shaped sound wave entering channel are integer times of the sound wave wavelength, and the inlet of the sound wave entering channel is opposite to the sound wave emitting end of the ultrasonic generator; the circle centers of the fan-shaped chambers are communicated with each other to form the aperture; the nozzle is disposed within the aperture. The multi-layer fan-shaped resonant cavity structure of the utility model has the advantages that sound waves enter the channel from the front side, multi-order FP resonance can be formed, the sound wave focusing effect is better, the acoustophoresis force at the nozzle is increased, and the diameter of the sprayed liquid drop is reduced.

Description

Droplet jetting device with sector resonant cavity focusing sound wave

Technical Field

The utility model relates to the technical field of high-precision electronic spray printing, in particular to a droplet spraying device with a fan-shaped resonant cavity for focusing sound waves.

Background

With intensive studies of electronic jet printing by extensive scholars, an acoustophoretic jet technology has been developed in recent years, which breaks through the limitation that the conventional ink jet printing is only suitable for low-viscosity fluids, and the electrofluidic jet is only suitable for materials with specific electromagnetic properties. The acoustophoretic jetting technology adopts acoustophoretic force as external force to act on the liquid drop, so that the characteristics of electricity, chemical, magnetism and the like of printing ink are not needed to be considered in the jet printing process.

According to the formula, since P is sound pressure, it can be seen that sound pressure has a great influence on droplet formation during acoustophoresis. Many studies have therefore applied acoustic focusing devices to acoustophoretic jetting, with typical ring resonators and fresnel acoustic lenses among other jet printing devices. Polyethylene glycol solution with the viscosity ranging from 0 to 1000 mPas is successfully sprayed out of the two, but the sizes of the sprayed liquid drops are slightly different due to the difference of the focusing effects of the two focusing devices, so that the influence of sound pressure on the sizes of the liquid drops is further verified.

An acoustophoresis composite flow focusing micro-nano jet printing method and device disclosed in Chinese patent No. 113978132B and an annular resonant cavity aggregation micro-droplet jet printing device disclosed in Chinese patent No. 216153424U are both annular resonant cavity focusing jet printing technologies. However, the focusing effect of the existing focusing structures such as resonant cavities is not obvious enough, and the generated acoustophoresis force is small, so that the diameter of the ejected liquid drop is relatively large. Therefore, it is necessary to further improve the acoustophoretic focusing structure so as to greatly improve the acoustophoretic force at the nozzle and reduce the size of the ejected liquid drops.

Disclosure of Invention

The utility model aims to solve the technical problem of providing a fan-shaped resonant cavity focusing acoustic wave droplet jetting device, which improves a focusing structure to increase the acoustophoresis force at a nozzle and reduce the size of jetted droplets.

In order to solve the technical problems, the technical solution of the utility model is as follows:

a droplet jetting device with a fan-shaped resonant cavity for focusing sound waves comprises an ultrasonic wave generating device, a liquid supply device, a nozzle communicated with the liquid supply device and a substrate arranged below the nozzle and used for receiving jet printing droplets, wherein the ultrasonic wave generating device is provided with a sound wave emitting end; the device is also provided with a resonant cavity assembly, wherein the resonant cavity assembly comprises a resonant cavity, an acoustic wave entering channel and an aperture; the resonant cavity is provided with at least two layers of fan-shaped cavities, each layer of fan-shaped cavity is at least communicated with one sound wave entering channel, the sound wave entering channel is in an arc shape coaxial with the fan-shaped cavity, the radiuses of the fan-shaped cavity and the arc-shaped sound wave entering channel are integer multiples of the sound wave wavelength, and the inlet of the sound wave entering channel is opposite to the sound wave emitting end; the circle centers of the fan-shaped chambers are communicated with each other to form the aperture; the nozzle is disposed within the aperture.

Preferably, the sound wave inlet channel is provided with a plurality of fan-shaped chambers, each fan-shaped chamber is respectively communicated with one sound wave inlet channel, and the fan-shaped chambers are not communicated with each other.

Preferably, the sound wave inlet channels are provided in plurality, each sound wave inlet channel is respectively communicated with one or more fan-shaped chambers, and the fan-shaped chambers are not communicated with each other or are communicated with each other through the sound wave inlet channels.

Preferably, the sector chambers of each layer have different central angles or different radial lengths.

Preferably, the body of the resonant cavity assembly is positioned on the surface of one side of the acoustic wave entering channel, and one or more grooves are formed in the body.

Preferably, the groove is an arc coaxial with the sector-shaped chamber.

Preferably, the resonant cavity is provided with three layers of fan-shaped cavities, namely a first cavity, a second cavity and a third cavity, and the three layers of fan-shaped cavities are three fan-shaped cavities with different radiuses; the three sound wave entering channels are respectively arranged at the positions of 4 times of sound wave wavelength, 3 times of sound wave wavelength and 2 times of sound wave wavelength.

Preferably, the first access channel, the second access channel and the third access channel are respectively communicated with the third chamber, the second chamber and the first chamber, and the three chambers are not communicated with each other; or the first access channel is communicated with the second chamber and the third chamber at the same time, and the second access channel and the third access channel are respectively communicated with the three chambers.

Preferably, the specific parameters of the resonant cavity assembly are that the height of the fan-shaped cavity is 1-2mm, or the difference between the aperture size and the outer diameter of the nozzle is 0.5-2mm; or the number of the grooves is 0-4, or the width of the grooves is 2-4.5mm; or the depth of the groove is 0.3-1.5mm.

Preferably, the liquid supply device is connected with the nozzle through a hose, and the hose and the nozzle are connected by a luer connector; the outer end of the aperture is connected with a liquid outlet pipe, and the outlet tip of the nozzle is positioned in the liquid outlet pipe; the nozzle is connected with an XYZ-axis fine adjustment device, and the position of the nozzle is fixed and adjusted through the XYZ-axis fine adjustment device.

After the scheme is adopted, the multi-acoustic wave channel formed by the fan-shaped cavity is arranged, so that the structure generates multi-order Fabry-Perot resonance (FP resonance), a standing wave mode is easy to form on the sub-wavelength structure, local effective focusing is formed, the sound pressure amplitude is improved, the performance of acoustophoretic injection can be greatly improved, and the size of injected liquid drops is reduced.

Specifically, the utility model has at least the following beneficial effects:

1. the resonant cavity provided by the utility model is provided with the multiple layers of fan-shaped cavities, the inlets of the sound wave inlet channels of each layer of fan-shaped cavity are opposite to the front surface of the sound wave emitting end of the ultrasonic wave generating device, so that more sound waves can enter the channels from the front surface of the sound wave, and then the FP resonance is shifted through the bending structure of the fan-shaped cavity, so that the positions of the sound wave generating position and the focusing position are positioned at non-coaxial positions.

2. The surface of the resonant cavity component can be provided with a plurality of grooves, evanescent wave field and Fabry-Perot resonance coupling can be generated, the effect of sub-wavelength sound wave focusing is improved, larger acoustophoresis force is generated, and the diameter of the sprayed liquid drop is further reduced.

3. The utility model can be provided with a plurality of sound wave inlet channels, each sound wave inlet channel is connected with the multi-layer fan-shaped cavity to form a mixed channel structure, and the sound pressure can be further increased.

4. The hose and the nozzle can be connected by adopting the luer connector, so that the problem that the hose falls off to influence the solution conveying when high-viscosity liquid is sprayed is avoided, and stable spraying of liquid drops is ensured.

5. The nozzle can be connected with the XYZ-axis fine adjustment device, so that the nozzle can move along three axes, and the nozzle is easy to place at the position with the best focusing effect.

Drawings

FIG. 1 is a schematic diagram of the structure of the present utility model;

FIG. 2 is a cross-sectional view of a resonant cavity assembly of the present utility model;

FIG. 3 is a front view of a resonant cavity assembly of the present utility model;

FIG. 4 is a perspective view of a resonant cavity assembly of the present utility model;

FIG. 5 is an exploded view of FIG. 1 of the resonant cavity assembly structure of the present utility model;

FIG. 6 is an exploded view of FIG. 2 of the resonant cavity assembly structure of the present utility model;

FIG. 7 is a schematic view of a three-layer sector chamber of a resonant cavity according to the present utility model;

FIG. 8 is a schematic diagram of structural parameters of a resonant cavity according to the present utility model;

FIG. 9 (a) is a schematic diagram of a LLL type multi-channel structure of a resonant cavity assembly according to the present utility model;

FIG. 9 (b) is a schematic diagram of the FLL-type multi-channel structure of the resonant cavity assembly according to the present utility model;

FIG. 9 (c) is a schematic illustration of a hybrid multi-channel structure of a resonant cavity assembly in accordance with the present utility model;

FIG. 9 (d) is a schematic illustration of a hybrid multi-channel structure modified for a resonant cavity assembly in accordance with the present utility model;

FIG. 11 is a plot of the acoustic field profile of a multi-channel sector resonator structure of the present utility model in an aperture at a frequency of 20 kHz;

FIG. 10 is a graph of sound pressure results for the different multi-channel structure of FIG. 9;

FIG. 12 is a graph showing the effect of channel width on sound pressure amplitude for a resonant cavity assembly according to the present utility model;

FIG. 13 is a graph of the effect of the pore size of the resonator assembly on the magnitude of sound pressure around the nozzle in accordance with the present utility model;

FIG. 14 is a graph showing the effect of the number of grooves of a resonator assembly on the magnitude of sound pressure according to the present utility model;

fig. 15 is a graph showing the effect of the groove size of the resonant cavity assembly on the sound pressure amplitude.

Detailed Description

The utility model will be described in further detail with reference to the drawings and the specific examples.

The utility model discloses a fan-shaped resonant cavity focused acoustic droplet ejecting device, which is a preferred embodiment of the utility model, as shown in fig. 1-4, and comprises an ultrasonic wave generating device 1, a liquid supply device 2, a nozzle 3, a substrate 4, a resonant cavity assembly 5, an XYZ shaft fine adjustment device 6 and a luer connector 7. Wherein:

the ultrasonic generating device 1 is used for generating ultrasonic waves, and the sound wave emitting end of the ultrasonic generating device is opposite to the inlet of the subsequent resonant cavity assembly 5. The ultrasonic wave generating device 1 may include a pulse generating device 11, a power amplifier 12, and an acoustic wave transmitting end 13. The pulse generator 11 sends out pulse signals, the pulse signals are amplified by the power amplifier 12, and then ultrasonic waves are sent out by the sound wave transmitting end 13.

The liquid supply device 2 is arranged to deliver a spray liquid into the nozzle 3. Which is connected to the nozzle 3 by a hose. Further, the hose and the nozzle 3 can be connected by a luer connector 7, so that the problem that the hose falls off to influence solution delivery when high-viscosity liquid is sprayed is avoided, and stable spraying of liquid drops is ensured.

The nozzle 3 may be a glass nozzle that is fixed within the aperture 53 of the subsequent resonator assembly 5 and is located above the substrate 4.

The substrate 4 is arranged below the nozzle 3 for receiving the jet printing droplets. The substrate 4 may be placed on a moving platform which may be moved in three axes, thereby moving the substrate 4.

The resonant cavity assembly 5 is provided with a resonant cavity 51, at least two layers of fan-shaped chambers (three layers are provided in this embodiment, namely, a first chamber 511, a second chamber 512 and a third chamber 513) are provided in the resonant cavity 51, each layer of fan-shaped chamber is provided with at least one arc-shaped sound wave entering channel 52 concentric with the fan-shaped chamber, the radius of the fan-shaped chamber and the radius of the arc-shaped sound wave entering channel 52 are integer multiples of the sound wave wavelength, and the inlet of the sound wave entering channel 52 faces the sound wave emitting end 13, that is, the size range of the sound wave emitting end 13 covers the inlet of the sound wave entering channel 52. In addition, the circle centers of the fan-shaped chambers are mutually communicated to form an aperture 53. The nozzle 3 is disposed within the aperture 53. The working principle of the utility model is as follows: the ultrasonic wave emitted by the ultrasonic wave generating device 1 enters into each layer of fan-shaped cavity of the resonant cavity 51 from the sound wave entering channel 52, finally converges into the aperture 53 to form fabry-perot resonance, and sub-wavelength focusing is realized at the outlet of the nozzle 3, and the focused sound pressure focus generates sound pressure to form shearing force for the liquid drops ejected by the nozzle 3, so as to generate micron-sized liquid drops; finally, the droplets are deposited on the substrate 4 for patterning. The sound pressure generated by the ultrasonic wave generating device 1 is far smaller than the sound pressure required by the acoustophoretic printing, and the sound pressure can be increased by focusing the sound wave through the resonant cavity 51, so that the sound pressure reaches the sound pressure required by the acoustophoretic printing. Each layer of cavity of the resonant cavity 51 forms first-order fabry-perot resonance at the aperture 53, and the multiple layers of cavities can form multi-order fabry-perot resonance, so as to realize sub-wavelength sound wave focusing, improve acoustophoresis force at the nozzle 3, and reduce the diameter of the ejected liquid drop.

Further, the fan-shaped chambers of each layer of the resonant cavity 51 may have different central angles, and the angle of the central angle is preferably not greater than 45 degrees. In theory, the larger the angle of the center angle of the fan-shaped chamber, the more sound waves enter, and the larger the sound pressure. However, too large a center angle results in a sector-shaped chamber having too large a width, even wider than the size of the sound-wave emitting end 13, so that sound waves cannot enter the chamber from the front, which is why the center angle cannot be too large. In order to make the sound wave enter the resonant cavity 51 from the front, if the center angle of the selected fan-shaped cavity is larger, the two sides of the cavity can be cut in parallel lines, so that the width dimension of the fan-shaped cavity does not exceed the dimension of the sound wave emitting end 13. As shown in fig. 7, fig. 7 (a) shows a structure of the first chamber 511, fig. 7 (b) shows a structure of the second chamber 512, and fig. 7 (c) shows a structure of the third chamber 513, wherein two sides of the first and second chambers exceed the size of the sound wave emitting end 13, i.e. are cut by parallel lines. Furthermore, the sector radius dimensions (i.e., the chamber length) of each layer of sector-shaped chambers may also be different.

In this embodiment, the resonant cavity 51 is provided with three layers of fan-shaped chambers, namely a first chamber 511, a second chamber 512 and a third chamber 513. More specifically, the radius of the first chamber 511 is set to 3 times the wavelength of the sound wave, and the radii of the second chamber 512 and the third chamber 513 are set to 4 times the wavelength of the sound wave. The process of the ultrasonic wave entering the cavity of the resonant cavity 51 from the sound wave entering channel 52 can be regarded as a bending structure, so that the FP resonance is shifted, and the sound wave generating position and the focusing position are located at a non-coaxial position, that is, the ultrasonic wave generating device 1 and the nozzle 3 are not on the same axis, so that the sound wave can be opposite to the inlet of the resonant cavity 51 so as to enable more sound waves to enter the resonant cavity, and the size of the resonant device can be reduced.

The acoustic wave entry channels 52 may be provided in plurality, and each acoustic wave entry channel 52 may be connected to multiple layers of the fan-shaped chambers simultaneously, but each layer of the fan-shaped chambers must be in communication with at least one acoustic wave entry channel 52. In this embodiment, three acoustic wave inlet channels 52 are provided, namely, a first inlet channel 521, a second inlet channel 522 and a third inlet channel 523, where the first inlet channel 521 communicates with the second chamber 512 and the third chamber 513 at the same time, and the second inlet channel 522 and the third inlet channel 523 communicate with the three chambers at the same time. The first inlet channel 521, the second inlet channel 522, and the third inlet channel 523 are arc-shaped channels to ensure that the distance of the sound waves entering the nozzle 3 at the aperture 53 is an integer multiple of the wavelength of the sound waves. The acoustic wave entry channel 52 connects the multiple chambers to further increase acoustic pressure.

The body of the resonator assembly 5 is located on the surface of the side of the acoustic wave entry channel 52, and a plurality of grooves 56 may be provided. The grooves 56 can generate evanescent wave field and Fabry-Perot resonance coupling, so that the effect of sub-wavelength sound wave focusing is improved, larger acoustophoresis force is generated, and the diameter of the ejected liquid drops is further reduced. While the groove 56 is theoretically not limited in location or shape, the groove 56 is an arcuate groove coaxial with the fan-shaped chamber in order to avoid the sound wave from entering the channel 52. In addition, the number of the grooves 56 is preferably 1 to 4.

In addition, in order to provide a multi-layered sector cavity inside the body of the resonator assembly 5, it may be implemented in various structures. In particular, as shown in fig. 5-6, the body of the resonator module 5 includes a main body 546 and five mounting plates, i.e., first to first mounting plates. The body 546 is provided with a mounting groove, one side wall of which is an arc-shaped side wall. The first mounting piece 541, the second mounting piece 542 and the third mounting piece 543 are sequentially mounted in the mounting groove outwards, the fourth mounting piece 544 and the fifth mounting piece 545 are further mounted at intervals on the outer side of the mounting groove close to the arc-shaped side wall, and the fourth mounting piece 544 and the fifth mounting piece 545 are arc-shaped. The first, second and third mounting plates 541, 542 and 543 are respectively provided with through holes 531 with opposite positions, each mounting plate is provided with a fan-shaped groove with the center of each through hole 531 towards the edge thereof, the arc-shaped sides of the fan-shaped grooves are open, and the open sides of the arc-shaped sides of the fan-shaped grooves of each mounting plate are also corresponding arcs. The first, second and third mounting plates 541, 542, 543 are disposed with one side of the fan-shaped groove facing the main body 546 and are sequentially mounted in the mounting groove of the main body 546, such that a gap is formed between the first mounting plate 541 and the main body 546 and between the adjacent two mounting plates, which is the fan-shaped chamber or a portion of the fan-shaped chamber of the resonant cavity 51, and the fourth mounting plate 544 and the fifth mounting plate 545 compensate for another portion of the corresponding fan-shaped chamber. Specifically, the layer gap between the main body 546 and the first mounting plate 541 forms the third chamber 513; the layer gap between the first mounting plate 541 and the second and fourth mounting plates 542, 544 forms the second chamber 512; the layer gap between the second mounting piece 542 and the third and fifth mounting pieces 543, 545 forms the first chamber 511. In order to enable the acoustic wave entering channel 52 to connect with the multi-layer chamber, the fan-shaped slot of the second mounting plate 542 is provided with a first arc slot 542a corresponding to the arc edge of the third mounting plate 543, and the fan-shaped slot of the first mounting plate 541 is provided with a second arc slot 541a and a third arc slot 541b corresponding to the arc edges of the second and third mounting plates 542 and 543, respectively. A channel gap is reserved between the arc edge of the first mounting piece 541 and the arc side wall of the mounting groove, a channel gap is also reserved between the arc side wall of the mounting groove and the fourth mounting piece 544, and the two channel gaps form the first access channel 521. The spacing between the fourth and fifth mounting tabs 544, 545 is arranged to correspond to the second arcuate slot 541a to form the second access passage 522. The interval between the arc edges of the fifth mounting piece 545 and the third mounting piece 543 is set corresponding to the first arc slot 542a and the third arc slot 541b, so as to form the third access passage 523. The main body 546 is also provided with a through hole 531 corresponding to the through holes 531 of the first, second and third mounting plates 541, 542, 543, and the four through holes 531 together form the aperture 53. The outer end of the through hole of the main body 546 is connected with a liquid outlet pipe 55, and the connection mode can be interference fit; the outlet tube 55 may be a sub-gram force tube; the outlet tip of the nozzle 3 is located in the outlet pipe 55. The main body 546 is disposed on the outer side of the arc-shaped sidewall, the fourth mounting piece 544, the fifth mounting piece 545 and the third mounting piece 543, respectively, with a groove 56, and the groove 56 may be a corresponding arc shape. The main body 546 and the five mounting pieces can be connected with each other by adopting a matched convex-concave structure, so that the mounting is simple and the shearing force generated by the bolting can be avoided. The radii of the fan-shaped grooves and the arc-shaped radii are integer multiples of the wavelength of the sound wave, and each of the through holes 531 is used as the axis. The radial lengths of the fan-shaped grooves on the first, second and third mounting plates 541, 542 and 543 decrease in sequence, and the central angles decrease in sequence.

The XYZ axis fine adjustment device 6 is connected with the nozzle 3, and is used for fixing the nozzle 3 on one hand, and on the other hand, the nozzle 3 can be subjected to XYZ direction fine adjustment in the aperture 53 through adjustment of the XYZ axis fine adjustment device 6, so that the outlet tip of the nozzle 3 can be positioned at the optimal position of sound wave focusing, and the optimal state of acoustophoresis spraying is achieved. The optimal focusing position of the sound wave can be obtained by simulation analysis.

When the device works, the ultrasonic wave generating device 1 sends out pulse signals, and the pulse signals are transmitted to the piezoelectric ceramics of the sound wave transmitting end 13 through the lead wires to do mechanical vibration, so that ultrasonic waves are generated. The ultrasonic waves propagate through the air and reach the position of the sound wave entering channel 52 on the surface of the resonant cavity assembly 5, and enter the multi-layer fan-shaped cavity of the resonant cavity 51 in a vertical incidence mode, namely, the three fan-shaped cavities in the embodiment, and then are converged in the aperture 53 to form multi-order Fabry-Perot resonance, so that sub-wavelength sound wave focusing is realized, and sound pressure is increased. The liquid supply device 2 conveys ink to be printed to the nozzle 3 through a hose, the position of the nozzle 3 can be finely adjusted in advance through the XYZ axis fine adjustment device 6, and the tip of the nozzle 3 is adjusted at the optimal position of sound wave focusing, and the sound pressure shearing force can be generated at the optimal position, so that micron-sized liquid drops are generated. Finally, the droplets produced are subjected to patterned deposition by controlling the travel rate of the liquid supply device 2 and the movement of the substrate 4. The multi-layer chamber of the resonant cavity 51 realizes fabry-perot resonance and sub-wavelength sound wave focusing, further increases sound pressure, improves acoustophoresis force at the nozzle 3, and reduces the diameter of the ejected liquid drop. Meanwhile, the grooves 56 formed on the surface of the resonant cavity assembly 5 can generate evanescent wave field and Fabry-Perot resonance coupling, so that the effect of sub-wavelength sound wave focusing is improved, larger acoustophoresis force is generated, and the diameter of the sprayed liquid drops is further reduced.

The utility model can adopt Comsol finite element analysis software to carry out sound field simulation modeling on the whole device so as to verify the effect and optimize the structure and parameters of the resonant cavity. In the fax process, the transmission medium in the fan-shaped chamber is selected to be air, the sound wave generation frequency is 20kHz, and the structural parameters of the resonant cavity assembly 5 are as shown in fig. 8, which is provided with three fan-shaped chambers, namely a first chamber 511, a second chamber 512 and a third chamber 513, and three sound wave inlet channels 52, namely a first inlet channel 521, a second inlet channel 522 and a third inlet channel 523, and the three sound wave inlet channels 52 are respectively at the positions of 4λ, 3λ and 2λ; in the figure: a is the sector chamber height, b the diameter of the aperture 53, c is the width of the groove 56, d is the depth of the groove 56, and λ is the wavelength of the incident sound wave.

Based on the above basic structure, the present utility model designs various multi-channel (one channel is the path that sound waves travel from one sound wave entering channel 52 to one fan-shaped chamber reaching the aperture 53), and fig. 9 is a cross-sectional view of 4 multi-channel structures. Wherein: fig. 9 (a) shows a LLL-type multi-channel structure, i.e., one acoustic wave inlet channel 52 corresponds to one sector-shaped chamber, and the three channels are not communicated with each other; fig. 9 (b) is an FLL type multi-channel structure, that is, a third sound wave inlet channel 523 communicates with the first chamber 511, a second sound wave inlet channel 522 communicates with both the first and second chambers 511, 512, and the length of the first chamber 511 is extended to 3λ, and the third chamber 513 passes through the first sound wave inlet channel 521 and is not in communication with the other two chambers; fig. 9 (c) is a mixed multi-channel structure in which three fan-shaped chambers are all communicated with each other, wherein the second and third inlet channels 522, 523 are simultaneously communicated with the three fan-shaped chambers, and the first inlet channel 521 is simultaneously communicated with the second and third chambers 512, 513, and the length of the second chamber 512 is extended to 4λ, and the length of the first chamber 511 is extended to 3λ; fig. 9 (d) is a modified hybrid multichannel structure, which differs from the hybrid multichannel structure of fig. 9 (c) in that a plurality of grooves 56 are provided. The utility model simulates the spraying device through software, and sequentially carries out simulation comparison on the multichannel structure, the channel width a (namely the height of the fan-shaped cavity), the size b of the aperture 53, the number of grooves and the groove sizes (c and d), and the simulation comparison effect is as follows.

Firstly, 4 multi-channel structures shown in fig. 9 are subjected to simulation analysis, and sound pressure amplitude is taken as the judging structure to determine which multi-channel structure has the best effect. In order to facilitate observation of the sound pressure amplitude around the glass nozzle 3, the nozzle tip portion in fig. 10 (a) is taken as a drawing group to show the sound pressure amplitude around the nozzle, the coordinates of the nozzle tip are-396 mm, and the sound pressure amplitude results of the final 4 multi-channel structures are shown in fig. 10 (b). It can be seen from fig. 10 (b) that when the LLL-type multichannel structure is changed into the FLL-type multichannel structure, the sound pressure amplitude value is slightly increased, the device is improved to obtain a mixed multichannel structure with greatly increased sound pressure amplitude value, grooves are added on the mixed multichannel structure to obtain an improved multichannel structure, and the simulation result shows that the improved multichannel structure has the best effect.

Fig. 11 shows spatial sound pressure level distributions of different lengths in the channel at a frequency of 20kHz, respectively, wherein: small L (ABCL in fig. 11), medium L (DFGL in fig. 11), large L (HIKL in fig. 11), all of which exhibit typical fabry-perot resonance sound field distribution, demonstrating that fabry-perot resonance can occur simultaneously in channels of different lengths.

Then, simulation comparison was made on the variation of the channel width, and the variation of the sound pressure amplitude around the nozzle is given in fig. 12 when the channel width a is 1mm, 1.5mm, 2mm, 2.5mm, respectively. The sound pressure amplitude around the nozzle is significantly increased when the channel width is increased from 1mm to 2mm, and the absolute value of the sound pressure amplitude is instead decreased once the channel width is increased to 2.5mm. From this, it can be determined that the channel width a is preferably 1 to 2mm, and most preferably 2mm.

As for the influence of the aperture size b on the magnitude of the sound pressure around the nozzle, since the outer diameter of the glass nozzle is 1mm, the aperture sizes b are 1.5mm, 2mm, 2.5mm and 3mm are taken here. As can be seen from fig. 13, the sound pressure amplitude around the nozzle increases with the increase in the aperture size, but the sound pressure amplitude around the nozzle does not increase but slightly decreases at the aperture size of 3mm. This is because an increase in the aperture can increase the transmission coefficient of the acoustic wave, but when the transmission coefficient is too high, efficient coupling with the fabry-perot resonance is not possible, so that the sound pressure result is slightly lowered, and thus the aperture size is 1.5 to 3mm, preferably 2.5mm. In practical application, the size of the aperture is related to the outer diameter of the nozzle, and the difference between the aperture and the outer diameter is preferably 0.5-2 mm.

In the utility model, the grooves are additionally arranged on the surface of the multi-channel fan-shaped structure to be used as the continuation of the surface. Fig. 14 (a) shows the magnitude of sound pressure around the glass nozzle when the number of grooves is 0, 1, 2, 3, 4, respectively. It can be seen that the increase in the number of grooves is positively correlated to the sound pressure around the glass nozzle. Fig. 14 (b) shows a graph of the sound pressure level at the nozzle as a function of the number of grooves, and it can be seen from the trend of the curve in fig. 14 (b) that an increase in the number of grooves helps to increase the sound pressure level around the glass nozzle, but this effect is not infinite, and as the number of grooves increases to 4, the sound pressure level around the glass nozzle gradually becomes gentle. This may be due to the fact that the incident sound wave is transmitted through the aperture to the output end, and that the evanescent wave excited by the grooves at the entrance of the sound wave away from the aperture is already so attenuated as not to reach the aperture by the transmission through the aperture, so that an excessive number of grooves cannot significantly increase the sound pressure level around the glass nozzle.

Fig. 15 (a) shows the magnitude of the sound pressure amplitude around the nozzle as a function of the groove width at 20 kHz. As the groove width c increases, the sound pressure amplitude around the nozzle increases. Fig. 15 (b) shows the variation of the nozzle tip sound pressure amplitude with the groove width (the groove width is varied from 2 to 4.5 mm), from which it can be seen that the increase of the sound pressure at the nozzle is slowed down as the groove width is increased to a certain value. Fig. 15 (c) shows the sound pressure amplitude around the glass nozzle as a function of groove depth. As the groove depth d increases, the sound pressure amplitude around the nozzle increases, and when the groove depth increases to some extent, the sound pressure amplitude around the nozzle decreases instead. The increase of the initial value of the depth of the groove (from 0.3mm to 1.5 mm) adjusts the effective surface period of ASWs (surface acoustic waves) and optimizes the interaction of evanescent waves and Fabry-Perot resonance, so that the sound pressure amplitude at the periphery of the nozzle is effectively improved. However, with further increases in groove depth (from 1.5mm to 1.8 mm), the effective surface period of the asps changes, and sufficient momentum compensation cannot be obtained in the designed structure and at a specific frequency, so that the gain effect of sound pressure decreases, and therefore the sound pressure amplitude at the periphery of the nozzle significantly decreases. Both the depth d and the width c of the grooves have a significant effect on the component of the evanescent wave. The effect of the groove size on the structure was mainly examined on the effect of the groove width c and the groove depth d on the sound pressure around the nozzle, and as shown in fig. 15 (a) and 15 (c), it can be seen that both the groove depth and the groove width have a large effect on the structure.

The above description is only of the preferred embodiments of the present utility model, and should not be taken as limiting the technical scope of the present utility model, but all changes and modifications that come within the scope of the utility model as defined by the claims and the specification are to be embraced by the utility model.

Claims (10)

1. A droplet jetting device with a fan-shaped resonant cavity for focusing sound waves comprises an ultrasonic wave generating device, a liquid supply device, a nozzle communicated with the liquid supply device and a substrate arranged below the nozzle and used for receiving jet printing droplets, wherein the ultrasonic wave generating device is provided with a sound wave emitting end; the method is characterized in that: the device is also provided with a resonant cavity assembly, wherein the resonant cavity assembly comprises a resonant cavity, an acoustic wave entering channel and an aperture; the resonant cavity is provided with at least two layers of fan-shaped cavities, each layer of fan-shaped cavity is at least communicated with one sound wave entering channel, the sound wave entering channel is in an arc shape coaxial with the fan-shaped cavity, the radiuses of the fan-shaped cavity and the arc-shaped sound wave entering channel are integer multiples of the sound wave wavelength, and the inlet of the sound wave entering channel is opposite to the sound wave emitting end; the circle centers of the fan-shaped chambers are communicated with each other to form the aperture; the nozzle is disposed within the aperture.

2. A fan-shaped cavity focused acoustic wave droplet ejection apparatus according to claim 1, wherein: the sound wave entering channels are provided with a plurality of fan-shaped cavities, each fan-shaped cavity is communicated with one sound wave entering channel, and the fan-shaped cavities are not communicated with each other.

3. A fan-shaped cavity focused acoustic wave droplet ejection apparatus according to claim 1, wherein: the sound wave entering channels are provided with a plurality of sound wave entering channels, each sound wave entering channel is respectively communicated with one or more fan-shaped cavities, and the fan-shaped cavities are not communicated with each other or are communicated with each other through the sound wave entering channels.

4. A fan-shaped cavity focused acoustic wave droplet ejection apparatus according to claim 1, wherein: the fan-shaped chambers of each layer have different center angles or different radius lengths.

5. A fan-shaped cavity focused acoustic wave droplet ejection apparatus according to claim 1, wherein: the body of the resonant cavity component is positioned on the surface of one side of the sound wave entering channel and is provided with one or more grooves.

6. A fan-shaped cavity focused acoustic wave droplet ejection apparatus as defined in claim 5, wherein: the groove is arc-shaped coaxial with the fan-shaped cavity.

7. A fan-shaped cavity focused acoustic wave droplet ejection apparatus according to claim 1, wherein: the resonant cavity is provided with three layers of fan-shaped cavities, namely a first cavity, a second cavity and a third cavity, and the three layers of fan-shaped cavities are provided with three different radiuses; the three sound wave entering channels are respectively arranged at the positions of 4 times of sound wave wavelength, 3 times of sound wave wavelength and 2 times of sound wave wavelength.

8. A fan-shaped cavity focused acoustic wave droplet ejection apparatus as defined in claim 7, wherein: the first access channel, the second access channel and the third access channel are respectively communicated with the third chamber, the second chamber and the first chamber, and the three chambers are not communicated with each other; or the first access channel is communicated with the second chamber and the third chamber at the same time, and the second access channel and the third access channel are respectively communicated with the three chambers.

9. A fan-shaped cavity focused acoustic wave droplet ejection apparatus as defined in claim 5, wherein: the specific parameters of the resonant cavity component are that the height of the fan-shaped cavity is 1-2mm, or the difference between the aperture size and the outer diameter of the nozzle is 0.5-2mm; or the number of the grooves is 0-4, or the width of the grooves is 2-4.5mm; or the depth of the groove is 0.3-1.5mm.

10. A fan-shaped cavity focused acoustic wave droplet ejection apparatus according to claim 1, wherein: the liquid supply device is connected with the nozzle through a hose, and the hose is connected with the nozzle through a luer connector; the outer end of the aperture is connected with a liquid outlet pipe, and the outlet tip of the nozzle is positioned in the liquid outlet pipe; the nozzle is connected with an XYZ-axis fine adjustment device, and the position of the nozzle is fixed and adjusted through the XYZ-axis fine adjustment device.