An atomizing chip based on surface acoustic wave

Abstract

This invention discloses a surface acoustic wave (SAW)-based atomizing chip, comprising a piezoelectric substrate, interdigitated electrodes, and a strip-shaped microstructure. By adding the strip-shaped microstructure, droplets can more easily form a liquid film under the combined action of SAW and capillary tension, thereby improving atomization efficiency. The SAW atomizing chip of this invention has advantages such as low power consumption and high atomization efficiency. Simultaneously, the microstructure can isolate some heat to a certain extent, which is beneficial to the stability of droplet composition.

Description

Technical Field

[0001] This invention relates to the field of atomization device technology, and in particular to an atomization chip based on surface acoustic waves. Background Technology

[0002] In fields such as medical microfluidic manipulation, precision electronic equipment cooling, and inkjet printing, the atomization of microliter-sized droplets into aerosols is a key technology. Currently, droplet atomization methods include thermal conduction, electromagnetic force, and ultrasonic resonance, with thermal conduction being the most common. However, atomization devices based on thermal conduction suffer from drawbacks such as easy decomposition or contamination of the droplets, high temperatures, and potential safety hazards. Electromagnetic force-based atomization devices require high voltage and struggle to achieve precise control over tiny droplets. Ultrasonic resonance atomization devices based on bulk waves suffer from high power consumption, large device size, and uneven aerosol particle size distribution. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to address the deficiencies mentioned in the background art by providing a surface acoustic wave-based atomization chip.

[0004] To solve the above-mentioned technical problems, the present invention adopts the following technical solution:

[0005] A surface acoustic wave-based atomization chip includes a piezoelectric substrate, interdigitated electrodes, and a strip-shaped microstructure.

[0006] The interdigitated electrodes are disposed on the piezoelectric substrate, with a finger width and gap length both being λ / 4, and the number of interdigital pairs is [missing value]. n λ is the preset surface acoustic wave wavelength. n It is a natural number greater than or equal to 1;

[0007] The strip-shaped microstructure is disposed on the piezoelectric substrate and includes several parallel and equidistant straight grooves, which are parallel to the electrodes of the interdigitated electrodes.

[0008] The interdigitated electrodes and piezoelectric substrate constitute an interdigitated transducer, which is used to convert the incoming electrical signal into surface acoustic waves; the strip microstructure satisfies the Wenzel wetting model, which is used to enable the droplets on it to quickly form a liquid film under the action of surface acoustic waves based on the capillary effect, and the liquid film is atomized under the continuous action of surface acoustic waves.

[0009] As a further optimization of the surface acoustic wave-based atomizing chip of the present invention, it also includes several reflective gratings.

[0010] The plurality of reflective gratings are arranged in parallel and at equal intervals, and the strip-shaped microstructure is located on both sides of the interdigital electrode to reflect surface acoustic waves and improve the efficiency of the interdigital transducer.

[0011] The width of the reflective grating and the spacing between reflective gratings are both λ / 4; the length of the reflective grating is greater than or equal to the aperture of the interdigitated electrode. d ;

[0012] The reflective gratings are all parallel to the electrodes of the interdigital electrodes, and the distance between the reflective gratings and the electrodes of the interdigital electrodes is λ / 4.

[0013] As a further optimization of the surface acoustic wave-based atomizing chip of the present invention, the metallization rate of the interdigitated electrodes is 50%.

[0014] As a further optimization of the surface acoustic wave-based atomizing chip of the present invention, the strip-shaped microstructure is formed by directly machining straight grooves on the surface of the piezoelectric substrate.

[0015] As a further optimization of the surface acoustic wave-based atomizing chip of the present invention, the strip-shaped microstructure is fixed to the piezoelectric substrate by bonding or pasting.

[0016] As a further optimization of the surface acoustic wave-based atomizing chip of the present invention, the width of the straight groove in the strip microstructure is minimized under the premise that the strip microstructure satisfies the Wenzel wetting model.

[0017] As a further optimization of the surface acoustic wave-based atomizing chip of the present invention, the piezoelectric substrate is a rectangular lithium niobate wafer with a thickness of 0.5 mm.

[0018] Compared with the prior art, the present invention, employing the above technical solution, has the following technical effects:

[0019] 1. Low power consumption, non-contact with droplets, simple device structure, and easy to implement;

[0020] 2. The structure of the surface acoustic wave atomization chip has been optimized, making it easier for droplets to form liquid films, reducing power consumption and chip area. At the same time, the microstructure isolates part of the heat from the piezoelectric substrate, reducing the possibility of droplet components being decomposed. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of the present invention;

[0022] Figure 2 This is a schematic diagram of the interdigitated electrodes and the reflective grating in combination;

[0023] Figure 3 This is a cross-sectional view of the present invention during operation;

[0024] Figure 4 This is a schematic diagram showing the atomization of droplets on the strip-shaped microstructure during the operation of this invention.

[0025] In the figure, 1-piezoelectric substrate, 2-interdigital electrode, 3-reflective grating, 4-ribbon microstructure, 5-droplet. Implementation

[0026] The technical solution of the present invention will be further described in detail below with reference to the accompanying drawings:

[0027] This invention can be implemented in many different forms and should not be considered limited to the embodiments described herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully express the scope of the invention to those skilled in the art. In the drawings, components are enlarged for clarity.

[0028] like Figure 1 As shown, the present invention discloses an atomization chip based on surface acoustic waves, comprising a piezoelectric substrate, interdigitated electrodes, a strip microstructure, and several reflective gratings;

[0029] like Figure 2 As shown, the interdigitated electrodes are disposed on the piezoelectric substrate, with a finger width and gap length of λ / 4, and the number of interdigitated pairs is [missing information]. n λ is the preset surface acoustic wave wavelength. n It is a natural number greater than or equal to 1;

[0030] The strip-shaped microstructure is disposed on the piezoelectric substrate and includes several parallel and equidistant straight grooves, which are parallel to the electrodes of the interdigitated electrodes.

[0031] The interdigitated electrodes and piezoelectric substrate constitute an interdigitated transducer, which is used to convert the incoming electrical signal into surface acoustic waves; the strip microstructure satisfies the Wenzel wetting model, which is used to enable the droplets on it to quickly form a liquid film under the action of surface acoustic waves based on the capillary effect, and the liquid film is atomized under the continuous action of surface acoustic waves.

[0032] The plurality of reflective gratings are arranged in parallel and at equal intervals, and the strip-shaped microstructure is located on both sides of the interdigital electrode to reflect surface acoustic waves and improve the efficiency of the interdigital transducer.

[0033] The width of the reflective grating and the spacing between reflective gratings are both λ / 4; the length of the reflective grating is greater than or equal to the aperture of the interdigitated electrode. d ;

[0034] The reflective gratings are all parallel to the electrodes of the interdigital electrodes, and the distance between the reflective gratings and the electrodes of the interdigital electrodes is λ / 4, such as... Figure 2 As shown.

[0035] The metallization rate of the interdigitated electrodes is 50%.

[0036] The piezoelectric substrate is a rectangular lithium niobate wafer with a thickness of 0.5 mm and a wafer tangent of 128YX(II).

[0037] After the piezoelectric matrix and interdigitated electrodes are determined, the wave velocity of the surface acoustic wave is... v Determined by the piezoelectric material, combined with the preset surface acoustic wave wavelength. λ It can calculate the frequency of the external input electrical signal. f = v / λ .

[0038] The interdigitated electrodes and reflective grids are deposited on the surface of the piezoelectric substrate, with a thickness of several hundred nanometers, and are made of metals such as aluminum and chromium or gold.

[0039] The width of the straight grooves in the strip-shaped microstructure is minimized while satisfying the Wenzel wetting model. If the width of the straight grooves is too narrow, the strip-shaped microstructure does not satisfy the Wenzel wetting model, and droplets are prone to suspending above the microstructure, preventing sound waves from entering the droplets and thus preventing atomization. If the width of the straight grooves is too large, it will weaken capillary action, which is not conducive to the formation of a liquid film by the droplets.

[0040] The fabrication method for microstructures varies depending on the piezoelectric material. If the piezoelectric substrate is crystal, microstructures are fabricated directly on the surface of the piezoelectric substrate using hydrofluoric acid etching. If lithium niobate wafers are chosen as the piezoelectric material, the microstructures can be bonded to the wafer surface using photolithography. Alternatively, polymer materials with microstructures on their surface can be adhered to the piezoelectric substrate surface.

[0041] like Figure 3 As shown, the working principle of this invention is as follows: a droplet falls onto a strip-shaped microstructure, and a sinusoidal electrical signal is input to the interdigitated electrodes. The interdigitated electrodes excite surface acoustic waves on the surface of the piezoelectric substrate, and the surface acoustic waves propagate along the surface into the droplet. Under the combined action of acoustic flow and capillary action, the droplet moves in the direction of sound wave propagation to form a liquid film. Then, under the action of capillary waves, the droplet is rapidly atomized, such as... Figure 4 As shown.

[0042] It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the same meaning as in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless defined as herein.

[0043] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A surface acoustic wave-based atomizing chip, characterized in that, Includes piezoelectric matrix, interdigitated electrodes, and strip-shaped microstructures; The interdigitated electrodes are disposed on the piezoelectric substrate, with a finger width and gap length both being λ / 4, and the number of interdigital pairs is [missing value]. n λ is the preset surface acoustic wave wavelength. n It is a natural number greater than or equal to 1; The strip-shaped microstructure is disposed on the piezoelectric substrate and includes several parallel and equidistant straight grooves, which are parallel to the electrodes of the interdigitated electrodes. The interdigitated electrodes and piezoelectric substrate constitute an interdigitated transducer, which is used to convert the incoming electrical signal into surface acoustic waves; the strip microstructure satisfies the Wenzel wetting model, which is used to enable the droplets on it to quickly form a liquid film under the action of surface acoustic waves based on the capillary effect, and the liquid film is atomized under the continuous action of surface acoustic waves.

2. The surface acoustic wave-based atomizing chip according to claim 1, characterized in that, It also includes several reflective gratings; The plurality of reflective gratings are arranged in parallel and at equal intervals, and the strip-shaped microstructure is located on both sides of the interdigital electrode to reflect surface acoustic waves and improve the efficiency of the interdigital transducer. The width of the reflective grating and the spacing between reflective gratings are both λ / 4; the length of the reflective grating is greater than or equal to the aperture of the interdigitated electrode. d ; The reflective gratings are all parallel to the electrodes of the interdigital electrodes, and the distance between the reflective gratings and the electrodes of the interdigital electrodes is λ / 4.

3. The atomizing chip based on surface acoustic waves according to claim 1, characterized in that, The metallization rate of the interdigitated electrodes is 50%.

4. The atomizing chip based on surface acoustic waves according to claim 1, characterized in that, The strip-shaped microstructure is formed by directly machining straight grooves on the surface of the piezoelectric substrate.

5. The surface acoustic wave-based atomizing chip according to claim 1, characterized in that, The strip-shaped microstructure is fixed to the piezoelectric substrate by bonding or adhesive.

6. The surface acoustic wave-based atomizing chip according to claim 1, characterized in that, The width of the straight grooves in the strip microstructure is minimized under the premise that the strip microstructure satisfies the Wenzel wetting model.

7. The atomizing chip based on surface acoustic waves according to claim 1, characterized in that, The piezoelectric substrate is a rectangular lithium niobate wafer with a thickness of 0.5 mm.

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