Rearview mirror assembly, rearview mirror cleaning system and vehicle

Abstract

The utility model discloses a rearview mirror assembly, a rearview mirror cleaning system and a vehicle. The rearview mirror assembly comprises a rearview mirror and a cleaning device, and the single-phase unidirectional transducer is used for generating surface acoustic waves and is used for acting the surface acoustic waves on the mirror surface of the rearview mirror. According to the rearview mirror assembly, dirt such as liquid drops, accumulated snow, frost and condensed ice on the mirror surface of the rearview mirror can be removed, rapid cleaning of the mirror surface of the rearview mirror is achieved, the cleaning efficiency is improved, the manufacturing cost is low, and the energy conversion rate is high.

Description

Technical Field

[0001] This utility model relates to the field of vehicle manufacturing technology, and in particular to a rearview mirror assembly, a rearview mirror cleaning system having the rearview mirror assembly, and a vehicle having the rearview mirror cleaning system. Background Technology

[0002] When driving in rainy or foggy weather, rearview mirrors are easily blurred by rain, fog, or splashing mud, affecting the driver's driving safety.

[0003] In related technologies, two devices, an input transducer and an output transducer, are used to generate bidirectional sound waves to achieve automatic cleaning of components such as vehicle rearview mirrors. However, the manufacturing cost is high, the energy conversion rate is low, and the cleaning efficiency is low. Utility Model Content

[0004] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes a rearview mirror assembly that can remove dirt such as droplets, snow, frost, and ice from the mirror surface, achieving rapid cleaning of the rearview mirror surface, improving cleaning efficiency, with low manufacturing cost and high energy conversion rate.

[0005] A rearview mirror assembly according to an embodiment of the present invention includes: a rearview mirror; a single-phase unidirectional transducer, wherein the single-phase unidirectional transducer is used to generate surface acoustic waves and to apply the surface acoustic waves to the mirror surface of the rearview mirror.

[0006] According to the rearview mirror assembly of this utility model embodiment, a single-phase unidirectional transducer generates surface acoustic waves (SAWs) with a single propagation direction to drive droplets on the mirror surface to move in the direction of SAW propagation and detach from the mirror surface. This removes dirt such as droplets, snow, frost, and ice from the mirror surface, achieving rapid cleaning of the rearview mirror surface, improving cleaning efficiency, and ensuring that the vehicle's rearview mirror maintains a clear field of vision in various harsh environments, thereby improving driving safety. Furthermore, the SAW generated by the single-phase unidirectional transducer propagates in one direction, avoiding energy loss caused by SAW propagation in unwanted directions, significantly reducing energy loss, improving energy utilization efficiency, and because the sound wave energy is concentrated in a single direction, the sound wave energy can act more concentratedly on the droplets, thereby improving the sensitivity of the single-phase unidirectional method and further improving cleaning efficiency and effect.

[0007] According to some embodiments of the present invention, a rearview mirror assembly includes a wave channel formed within the single-phase unidirectional transducer. The wave channel has a first inner wall and a second inner wall that are relatively distributed. The first inner wall is provided with a first excitation acoustic wave finger strip, and the second inner wall is provided with a second excitation acoustic wave finger strip. The first excitation acoustic wave finger strip is spaced apart from the second inner wall, and the second excitation acoustic wave finger strip is spaced apart from the first inner wall. Furthermore, the wave channel also includes an acoustic reflection source finger strip located in the propagation direction of the surface acoustic waves of the first and second excitation acoustic wave finger strips, and the acoustic reflection source finger strip is provided with acoustic wave holes.

[0008] According to some embodiments of the present invention, in the rearview mirror assembly, the first excitation acoustic wave finger strip and the second excitation acoustic wave finger strip are parallel and spaced apart; and / or, there are multiple first excitation acoustic wave finger strips and multiple second excitation acoustic wave finger strips, and the multiple first excitation acoustic wave finger strips and multiple second excitation acoustic wave finger strips are staggered along the transmission direction of the surface acoustic wave; and / or, the length of the first excitation acoustic wave finger strip protruding toward the second inner wall is the same as the length of the second excitation acoustic wave finger strip protruding toward the first inner wall.

[0009] According to some embodiments of the present invention, in the rearview mirror assembly, a plurality of first excitation acoustic wave finger strips and a plurality of second excitation acoustic wave finger strips are distributed in a one-to-one correspondence to form a plurality of excitation acoustic wave finger strip groups, and each group of excitation acoustic wave finger strip groups is provided with the acoustic reflection source finger strip on the rear side.

[0010] According to some embodiments of the present invention, the rearview mirror assembly includes multiple acoustic reflection source fingers, and the multiple acoustic reflection source fingers are arranged one-to-one on the rear side of the multiple acoustic wave excitation finger groups.

[0011] According to some embodiments of the present invention, in the rearview mirror assembly, the acoustic reflection source finger strip is disposed on the first inner wall, and the length of the acoustic reflection source finger strip protruding toward the second inner wall is the same as the length of the first excitation sound wave finger strip protruding toward the second inner wall; or, the acoustic reflection source finger strip is disposed on the second inner wall, and the length of the acoustic reflection source finger strip protruding toward the first inner wall is the same as the length of the second excitation sound wave finger strip protruding toward the first inner wall.

[0012] According to some embodiments of the present invention, in the rearview mirror assembly, the single-phase unidirectional transducer is disposed at the top of the rearview mirror, and the single-phase unidirectional transducer is used to apply the surface acoustic wave from top to bottom to the mirror surface of the rearview mirror; or, the single-phase unidirectional transducer is disposed at the bottom of the rearview mirror, and the single-phase unidirectional transducer is used to apply the surface acoustic wave from bottom to top to the mirror surface of the rearview mirror.

[0013] According to some embodiments of the present invention, in the rearview mirror assembly, two single-phase unidirectional transducers are provided. One single-phase unidirectional transducer is located at the top of the rearview mirror to act the surface acoustic wave from top to bottom onto the mirror surface of the rearview mirror, and the other single-phase unidirectional transducer is located at the bottom of the rearview mirror to act the surface acoustic wave from bottom to top onto the mirror surface of the rearview mirror.

[0014] This utility model also proposes a rearview mirror cleaning system, including an electronic control board and the rearview mirror assembly described in any of the above embodiments. The electronic control board is electrically connected to the single-phase unidirectional transducer and is used to control the single-phase unidirectional transducer to generate surface acoustic waves.

[0015] According to some embodiments of the present invention, the rearview mirror cleaning system further includes a sensing element, which is electrically connected to the electronic control board. The sensing element is used to detect the single-phase unidirectional transducer, and the electronic control board is used to control the single-phase unidirectional transducer by controlling the detection result of the sensing element.

[0016] According to some embodiments of the rearview mirror cleaning system of the present invention, the electronic control board and the sensing element are connected through a signal acquisition circuit; and / or, a PWM generator and an amplifier circuit are sequentially connected between the electronic control board and the single-phase unidirectional transducer.

[0017] According to some embodiments of the present invention, the rearview mirror cleaning system includes a rearview mirror housing and a mirror surface, and the electronic control board is located inside the rearview mirror housing and on the back of the mirror surface.

[0018] This utility model also proposes a vehicle.

[0019] The vehicle according to the present invention includes the rearview mirror cleaning system described in any of the above embodiments.

[0020] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0021] The above and / or additional aspects and advantages of this utility model will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, in which:

[0022] Figure 1 This is a schematic diagram of the structure of a single-phase unidirectional transducer according to an embodiment of the present utility model;

[0023] Figure 2 This is a schematic diagram of the rearview mirror cleaning system according to an embodiment of the present utility model;

[0024] Figure 3 This is a structural schematic diagram of a rearview mirror assembly according to an embodiment of the present utility model;

[0025] Figure 4 This is a schematic diagram of the contact angle according to an embodiment of the present utility model;

[0026] Figure 5 This is a schematic diagram illustrating the principle of surface acoustic wave-driven droplet movement according to an embodiment of the present invention.

[0027] Figure label:

[0028] Rearview mirror cleaning system 1000,

[0029] Rearview mirror assembly 100, electronic control board 200, signal acquisition circuit 300, ADC current signal acquisition module 301, PWM generator 400, amplifier circuit 500, power supply 600.

[0030] Rearview mirror 1, rearview mirror housing 11, mirror surface 12, single-phase unidirectional transducer 2,

[0031] Wave channel 21, first inner wall 22, second inner wall 23, first excitation sound wave finger strip 24, second excitation sound wave finger strip 25, sound reflection source finger strip 26.

[0032] Surface acoustic wave 3, droplet 4, leaking surface wave 5, internal flow 6. Detailed Implementation

[0033] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0034] In the description of this utility model, it should be understood that the terms "center," "longitudinal," "transverse," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," etc., indicating the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, features defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.

[0035] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0036] Unless otherwise specified, the front-back direction in this application refers to the longitudinal direction of the vehicle, i.e., the X direction; the left-right direction refers to the lateral direction of the vehicle, i.e., the Y direction; and the up-down direction refers to the vertical direction of the vehicle, i.e., the Z direction.

[0037] The following is for reference. Figures 1-5 The rearview mirror assembly 100 according to an embodiment of the present utility model is described. The rearview mirror assembly 100 can remove dirt such as droplets 4, snow, frost, and ice from the mirror surface 12 of the rearview mirror 1, achieve rapid cleaning of the mirror surface 12 of the rearview mirror 1, improve cleaning efficiency, have low manufacturing cost, and high energy conversion rate.

[0038] like Figures 1-5 As shown, a rearview mirror assembly 100 according to an embodiment of the present invention includes: a rearview mirror 1 and a single-phase unidirectional transducer 2.

[0039] The single-phase unidirectional transducer 2 is used to generate surface acoustic waves 3 and to apply the surface acoustic waves 3 to the mirror surface 12 of the rearview mirror 1.

[0040] The single-phase unidirectional transducer 2 is used to generate surface acoustic waves 3 with a single propagation direction to achieve unidirectional propagation of surface acoustic waves 3. The generated surface acoustic waves 3 can act on the mirror surface 12 of the rearview mirror 1 to drive the droplets 4 (such as raindrops) on the mirror surface 12 of the rearview mirror 1 to move in the direction of propagation of surface acoustic waves 3 and detach from the mirror surface 12, thereby achieving the removal of droplets 4 on the mirror surface 12 of the rearview mirror 1. This achieves rapid cleaning of the mirror surface 12 of the rearview mirror 1, improves cleaning efficiency, and thus improves driving safety.

[0041] In this system, the mirror 12 of the rearview mirror 1 serves as a non-piezoelectric substrate. A single-phase unidirectional transducer 2 generates surface acoustic waves 3 on the surface of its mirror 12. These surface acoustic waves 3 propagate along the non-piezoelectric substrate and, upon passing the droplet 4, generate an acoustic flow (e.g., acoustic wave mode conversion) within the droplet 4. Figure 5 The internal flow 6 shown in the figure generates microfluidic dynamics that propel the droplet 4 rapidly away from the mirror surface 12 of the rearview mirror 1, thereby achieving the driving of the droplet 4 by the surface acoustic wave 3 in a single propagation direction, thus cleaning the mirror surface 12 of the rearview mirror 1 and keeping the rearview mirror 1 in a clear field of vision.

[0042] In addition, the surface acoustic wave 3 can not only drive the droplets 4 to detach from the mirror 12, but also prevent condensation on the mirror 12 due to temperature differences, thus ensuring that the rearview mirror 1 remains clear in rainy or cold and humid weather. This is because the vibration energy of the surface acoustic wave 3 can slightly disturb the arrangement of air molecules near the mirror 12, disrupting the conditions for condensation formation, thereby effectively preventing or quickly eliminating condensation on the mirror 12 and ensuring that the rearview mirror 1 maintains a clear field of vision in rainy or cold and humid weather.

[0043] Furthermore, surface acoustic waves 3 can also drive snow and ice to detach from the mirror surface 12. This is because the vibration characteristics of high-frequency surface acoustic waves 3 can directly act on the critical surface between the snow and ice and the mirror surface 12 of the rearview mirror 1. High-frequency vibration will generate local thermal effects and mechanical stress. Under the combined action of local thermal effects and mechanical stress, the ice and snow structure at the critical surface will loosen or even melt, thereby effectively reducing the adhesion between the ice and snow and the mirror surface 12. After that, the energy of surface acoustic waves 3 can further drive the loosened snow and ice to detach from the mirror surface 12, thereby achieving the removal of snow and ice on the mirror surface 12 of the rearview mirror 1.

[0044] Therefore, by generating surface acoustic waves 3 with a single propagation direction through the single-phase unidirectional transducer 2, the liquid droplets 4 on the mirror surface 12 of the rearview mirror 1 are driven to move in the direction of propagation of the surface acoustic waves 3 and detach from the mirror surface 12. This achieves the removal of dirt such as liquid droplets 4, snow, frost, and ice from the mirror surface 12 of the rearview mirror 1, realizing rapid cleaning of the mirror surface 12 of the rearview mirror 1, improving cleaning efficiency, and ensuring that the mirror surface 12 of the vehicle rearview mirror 1 maintains a clear field of vision in various harsh environments, thereby improving driving safety. Moreover, since the surface acoustic waves 3 generated by the single-phase unidirectional transducer 2 propagate in one direction, it avoids the energy loss caused by the surface acoustic waves 3 propagating in unwanted directions, thus significantly reducing energy loss and improving energy utilization efficiency. Furthermore, since the sound wave energy is concentrated in a single direction, the sound wave energy can act more concentratedly on the liquid droplets 4, thereby improving the sensitivity of the single-phase unidirectional transducer 2, further improving cleaning efficiency and cleaning effect.

[0045] In some embodiments, a wave channel 21 is formed inside the single-phase unidirectional transducer 2. The wave channel 21 has a first inner wall 22 and a second inner wall 23 that are relatively distributed. The first inner wall 22 is provided with a first excitation acoustic wave finger 24, and the second inner wall 23 is provided with a second excitation acoustic wave finger 25. The first excitation acoustic wave finger 24 is spaced apart from the second inner wall 23, and the second excitation acoustic wave finger 25 is spaced apart from the first inner wall 22.

[0046] Specifically, such as Figure 1As shown, a wave channel 21 is formed within the single-phase unidirectional transducer 2, through which surface acoustic waves 3 can flow to achieve their transmission. The wave channel 21 has a first inner wall 22 and a second inner wall 23 relatively distributed. The first inner wall 22 is provided with a first excitation acoustic wave finger 24, and the second inner wall 23 is provided with a second excitation acoustic wave finger 25. The first excitation acoustic wave finger 24 and the second excitation acoustic wave finger 25 can convert electrical signals into acoustic wave signals, forming bidirectional propagating surface acoustic waves 3 under the piezoelectric effect, and exciting the surface acoustic waves 3 to propagate in the wave channel 21, as shown. Figure 1 As shown in the left-right direction, surface acoustic waves 3 will be generated that propagate to the left and right.

[0047] The first excitation wave finger 24 is spaced apart from the second inner wall 23, and the second excitation wave finger 25 is spaced apart from the first inner wall 22. This ensures that the surface acoustic wave 3 can propagate freely in the wave channel 21 and avoids unnecessary reflection and interference, thereby ensuring that the sound wave energy is not lost.

[0048] Furthermore, the wave channel 21 is also provided with an acoustic reflection source finger strip 26, which is located in the direction of propagation of the surface acoustic wave 3 of the first excitation acoustic wave finger strip 24 and the second excitation acoustic wave finger strip 25, and the acoustic reflection source finger strip 26 is provided with an acoustic wave hole.

[0049] Specifically, such as Figure 1 As shown, a sound reflection source finger strip 26 is also provided in the wave channel 21. The sound reflection source finger strip 26 is mainly used to reflect the surface acoustic wave 3, such as... Figure 1 As shown in the left-right direction, the acoustic reflection source finger strip 26 is arranged along the left-right direction. The propagation direction of the surface acoustic wave 3 is the left-right direction. Thus, the acoustic reflection source finger strip 26 is located in the propagation direction of the surface acoustic wave 3 of the first excitation acoustic wave finger strip 24 and the second excitation acoustic wave finger strip 25. In this way, the acoustic reflection source finger strip 26 can effectively reflect the surface acoustic wave 3 excited by the first excitation acoustic wave finger strip 24 and the second excitation acoustic wave finger strip 25. Moreover, the acoustic reflection source finger strip 26 can cancel and reflect to suppress the sound wave energy propagating to the left and enhance the sound wave energy propagating to the right. This can realize the transmission of sound wave energy in a single direction, improve the utilization efficiency of surface acoustic wave 3 energy, and thus improve the performance of the single-phase unidirectional transducer 2. It also reduces the transmission of sound waves in other unnecessary directions, thereby improving the cleaning efficiency of the mirror surface 12 of the rearview mirror 1.

[0050] Among them, the sound reflection source finger strip 26 is provided with sound wave holes, such as Figure 1 As shown, the aperture size of the acoustic aperture is Figure 1The W shown is equal to the length of the overlap between the acoustic reflection source finger 26, the first excitation acoustic wave finger 24, and the second excitation acoustic wave finger 25 in the left-right direction. It determines the width of the wavelength of the surface acoustic wave 3. The acoustic aperture can effectively allow the surface acoustic wave 3 to pass through, effectively reflect and cancel the surface acoustic wave 3 propagating to the left, and effectively strengthen the surface acoustic wave 3 propagating to the right.

[0051] In some embodiments, the first excitation acoustic wave finger 24 and the second excitation acoustic wave finger 25 are spaced apart in parallel.

[0052] Specifically, such as Figure 1 As shown, the first excitation acoustic wave finger strip 24 and the second excitation acoustic wave finger strip 25 are distributed parallel to each other at a certain distance. This can effectively reduce the reflection and scattering of surface acoustic waves 3 inside the single-phase unidirectional transducer 2, allowing surface acoustic waves 3 to propagate in the left and right directions, thereby improving the transmission efficiency of surface acoustic waves 3 and reducing the energy loss of surface acoustic waves 3.

[0053] In other embodiments, there are multiple first excitation acoustic wave fingers 24 and multiple second excitation acoustic wave fingers 25, and the multiple first excitation acoustic wave fingers 24 and multiple second excitation acoustic wave fingers 25 are staggered along the transmission direction of the surface acoustic wave 3.

[0054] In other words, the first excitation acoustic wave finger strip 24 and the second excitation acoustic wave finger strip 25 can both be set to two, three, four or even more, and the multiple first excitation acoustic wave finger strips 24 and the multiple second excitation acoustic wave finger strips 25 are staggered along the propagation direction of the surface acoustic wave 3. In this way, a stronger acoustic wave intensity can be generated by the staggered excitation of the multiple first excitation acoustic wave finger strips 24 and the multiple second excitation acoustic wave finger strips 25, thereby improving the excitation efficiency and reducing the reflection and scattering of the surface acoustic wave 3 during the propagation process. That is, it is more conducive to the formation of directional propagation of the surface acoustic wave 3, thereby improving the propagation efficiency of the surface acoustic wave 3, reducing the energy loss of the surface acoustic wave 3, and thus improving the reliability and stability of the single-phase unidirectional transducer 2.

[0055] Specifically, such as Figure 1 As shown, there are two first excitation acoustic wave fingers 24 and two second excitation acoustic wave fingers 25, and the two first excitation acoustic wave fingers 24 and the two second excitation acoustic wave fingers 25 are staggered in the transmission direction of the surface acoustic wave 3, that is, in the left and right direction.

[0056] In other embodiments, the length of the first excitation acoustic wave finger 24 protruding toward the second inner wall 23 is the same as the length of the second excitation acoustic wave finger 25 protruding toward the first inner wall 22.

[0057] Specifically, such as Figure 1As shown, the first excitation wave finger 24 protrudes towards the direction close to the second inner wall 23 and is spaced apart from the second inner wall 23, and the second excitation wave finger 25 protrudes towards the direction close to the first inner wall 22 and is spaced apart from the first inner wall 22. The length of the first excitation wave finger 24 protruding towards the second inner wall 23 and the length of the second excitation wave finger 25 protruding towards the first inner wall 22 are the same. Therefore, the obstruction and reflection encountered by the surface acoustic wave 3 during propagation will be more uniform, thereby reducing energy loss, improving the propagation efficiency of the surface acoustic wave 3, and making it easier to control and adjust the phase relationship of the surface acoustic wave 3 to achieve specific acoustic interference effects. It is also convenient to manufacture, which can improve manufacturing efficiency. Furthermore, when one of the first excitation wave finger 24 or the second excitation wave finger 25 is damaged or fails, the other first excitation wave finger 24 or the second excitation wave finger 25 can still work normally, which can improve the working stability and reliability of the single-phase unidirectional transducer 2.

[0058] In actual design, the first inner wall 22 can be the inner wall of the first busbar, the second inner wall 22 can be the inner wall of the second busbar, the first excitation acoustic wave finger 24 and the second excitation acoustic wave finger 25 can be interdigitated electrodes, and thus the first busbar can be connected to the first electrode, and the second busbar can be connected to the second electrode.

[0059] In some embodiments, a plurality of first excitation acoustic wave fingers 24 and a plurality of second excitation acoustic wave fingers 25 are distributed in a one-to-one correspondence to form a plurality of excitation acoustic wave finger groups, and each group of excitation acoustic wave finger groups is provided with an acoustic reflection source finger 26 on its rear side.

[0060] Specifically, such as Figure 1 As shown, two first excitation acoustic wave fingers 24 and two second excitation acoustic wave fingers 25 are provided. One first excitation acoustic wave finger 24 and one second excitation acoustic wave finger 25 are respectively distributed on the left side of the single-phase unidirectional transducer 2, and the other first excitation acoustic wave finger 24 and the other second excitation acoustic wave finger 25 are respectively distributed on the right side of the single-phase unidirectional transducer 2, thus forming two groups of excitation acoustic wave fingers. The two groups of excitation acoustic wave fingers are arranged along the propagation direction of the surface acoustic wave 3. The surface acoustic waves 3 excited by the two groups of excitation acoustic wave fingers can be superimposed to enhance the intensity of the surface acoustic wave 3 and increase the energy in the propagation direction of the surface acoustic wave 3.

[0061] Among them, the rear side of each group of excitation sound wave finger strips is... Figure 1The right side shown is equipped with acoustic reflection source bar 26. The acoustic reflection source bar 26 can reflect the surface acoustic wave 3, and send a part of the surface acoustic wave 3 that is propagating to the left to propagate to the right to enhance the energy of the surface acoustic wave 3 propagating to the right. It can also cancel a part of the surface acoustic wave 3 propagating to the left, thereby suppressing the generation of surface acoustic wave 3 propagating to the left. This realizes the propagation of surface acoustic wave 3 in a single direction, improves the utilization rate of surface acoustic wave 3, and thus improves the performance of single-phase unidirectional transducer 2.

[0062] Furthermore, by placing the acoustic reflection source finger strip 26 on the rear side of the excitation acoustic wave finger strip group, it can be ensured that the reflected surface acoustic wave 3 is consistent with the phase signal of the rightward propagating surface acoustic wave 3, thereby effectively enhancing the intensity of the surface acoustic wave 3.

[0063] In some embodiments, there are multiple acoustic reflection source fingers 26, and the multiple acoustic reflection source fingers 26 are disposed one-to-one with each other on the rear side of the multiple excitation acoustic wave finger groups.

[0064] That is, each group of excitation sound wave finger strips is provided with a sound reflection source finger strip 26 on the rear side, such as Figure 1 As shown, two acoustic reflection source finger strips 26 are provided, and the rear side of the two sets of excitation acoustic wave finger strips is... Figure 1 The right side shown is equipped with a sound reflection source bar 26.

[0065] In this way, it can be ensured that the surface acoustic wave 3 of each group of excitation sound wave finger strips can be reflected, and that the phase signal of the surface acoustic wave 3 reflected by the sound reflection source finger strip 26 of each group of excitation sound wave finger strips is consistent with that of the surface acoustic wave 3 propagating to the right. It can also enable the surface acoustic wave 3 propagating to the left to be reflected multiple times, thereby improving the reflection effect and enabling the surface acoustic wave 3 propagating to the left to propagate to the right more effectively, further enhancing the intensity of the surface acoustic wave 3 propagating to the right.

[0066] With this configuration, if one of the acoustic reflection source bars 26 is damaged or fails, the other acoustic reflection source bars 26 can still continue to work normally, thereby improving the working stability and reliability of the single-phase unidirectional transducer 2, and thus enabling more stable and reliable cleaning of the mirror surface 12 of the rearview mirror 1.

[0067] In some embodiments, the acoustic reflection source finger 26 is disposed on the first inner wall 22, and the length of the acoustic reflection source finger 26 protruding toward the second inner wall 23 is the same as the length of the first excitation sound wave finger 24 protruding toward the second inner wall 23; or, the acoustic reflection source finger 26 is disposed on the second inner wall 23, and the length of the acoustic reflection source finger 26 protruding toward the first inner wall 22 is the same as the length of the second excitation sound wave finger 25 protruding toward the first inner wall 22.

[0068] Specifically, such as Figure 1As shown, the acoustic reflection source finger strip 26 is disposed on the second inner wall 23, and the length of the acoustic reflection source finger strip 26 protruding towards the first inner wall 22 is the same as the length of the second excitation acoustic wave finger strip 25 protruding towards the first inner wall 22. Thus, in the propagation direction of the surface acoustic wave 3, the length of the overlapping part of the acoustic reflection source finger strip 26 and the second excitation acoustic wave finger strip 25 is the same, which is beneficial to maintain the same phase and amplitude of the surface acoustic wave 3 during propagation, thereby improving the propagation efficiency and accuracy of the surface acoustic wave 3, and can accurately transmit the surface acoustic wave 3 propagating to the left to propagate to the right, so as to superimpose it with the original surface acoustic wave 3 propagating to the right.

[0069] Therefore, the single-phase unidirectional transducer 2 of this utility model has low loss, large bandwidth, stable performance and strong adaptability, thus it can generate higher energy density and more stable waveform when exciting surface acoustic waves 3, thereby improving cleaning efficiency. In addition, the single-phase unidirectional transducer 2 is easy to miniaturize and integrate, which helps to reduce the size and cost of the entire cleaning system.

[0070] In some embodiments, a single-phase unidirectional transducer 2 is disposed on the top of the rearview mirror 1, and the single-phase unidirectional transducer 2 is used to apply surface acoustic waves 3 from top to bottom to the mirror surface 12 of the rearview mirror 1.

[0071] In other words, a single-phase unidirectional transducer 2 can be placed on top of the rearview mirror 1, and the single-phase unidirectional transducer 2 can generate surface acoustic waves 3 that propagate downward from the top of the rearview mirror 1. Thus, the surface acoustic waves 3 act on the mirror surface 12 of the rearview mirror 1 from top to bottom, thereby achieving effective cleaning of the mirror surface 12 of the rearview mirror 1.

[0072] Alternatively, a single-phase unidirectional transducer 2 is located at the bottom of the rearview mirror 1, and the single-phase unidirectional transducer 2 is used to apply the surface acoustic wave 3 from bottom to top to the mirror surface 12 of the rearview mirror 1.

[0073] In other words, a single-phase unidirectional transducer 2 can be placed at the bottom of the rearview mirror 1, and the single-phase unidirectional transducer 2 can generate surface acoustic waves 3 that propagate upward from the bottom of the rearview mirror 1. Thus, the surface acoustic waves 3 act on the mirror surface 12 of the rearview mirror 1 from bottom to top, so as to effectively clean the mirror surface 12 of the rearview mirror 1.

[0074] It should be noted that when the surface acoustic wave 3 propagates to the droplet 4 on the mirror 12 of the rearview mirror 1, the acoustic field flow generates a pressure difference on both sides of the microfluidic. This pressure difference first causes the droplet 4 to deform. When the pressure difference overcomes the critical force of solid-liquid friction, surface tension, etc., the droplet 4 will deform along the propagation direction of the surface acoustic wave 3. This process realizes the driving of the microfluidic by the surface acoustic wave 3, enabling the droplet 4 to be autonomously removed from the mirror 12, thus achieving the cleaning purpose.

[0075] The rearview mirror 1 serves as the non-piezoelectric substrate of the single-phase unidirectional transducer 2 and is the object that needs to be cleaned. Its composite glass material has good transparency and stability for the propagation of surface acoustic waves 3. At a determined resonant frequency, the single-phase unidirectional transducer 2 excites unidirectional propagating surface acoustic waves 3 on the mirror surface 12 of the rearview mirror 1. The surface acoustic waves 3 drive the droplets 4 in a directional manner.

[0076] Taking a single-phase unidirectional transducer 2 installed on top of the rearview mirror 1 as an example, the contact angle of the droplet 4 on the mirror surface 12 of the rearview mirror 1 is determined by the surface tension at the interface of the solid, liquid, and gas. Figure 4 The relationship between the stationary contact angle and surface tension of the smooth surface shown in the figure satisfies:

[0077] Cosθ=(α-β) / γ

[0078] Where α, β, and γ represent the surface tensions at the solid-gas, solid-liquid, and liquid-gas interfaces, respectively, and θ is the contact angle when the three forces of solid, liquid, and gas are in equilibrium. When θ < 90°, the solid surface is hydrophilic; when θ > 90°, the solid surface is hydrophobic. Most surfaces in nature have a certain degree of roughness, which increases the contact area between the liquid and the solid surface.

[0079] The single-phase unidirectional transducer 2 at the top of the rearview mirror 1 drives the droplet 4 on the mirror surface 12 of the rearview mirror 1 to slide downwards. The force pushing the droplet 4 on the mirror surface 12 of the rearview mirror 1 is as follows: Figure 5 As shown:

[0080]

[0081] like Figure 5 As shown, surface acoustic waves 3 form leaking surface waves 5 on the mirror 12, which leak into the droplet 4, generating an internal flow 6. In the formula, R is the radius of the droplet 4. Due to the wetting hysteresis phenomenon, θa and θr are the forward and backward angles of the driven droplet 4, respectively. In addition to the acoustic flow effect of surface acoustic waves 3 bringing driving thrust Fs to the droplet 4, the droplet 4 on the surface of the rearview mirror 1 is also subjected to gravity mg. The resultant force of gravity mg and Fs causes the droplet 4 to detach from the mirror 12 of the rearview mirror 1, achieving effective cleaning of the mirror 12 of the rearview mirror 1. At the same time, when the droplet 4 moves, it will also cover and carry away other dust and impurities on the mirror 12 to improve the cleaning effect and make the mirror 12 of the rearview mirror 1 more thoroughly cleaned.

[0082] In some embodiments, two single-phase unidirectional transducers 2 are provided. One single-phase unidirectional transducer 2 is provided at the top of the rearview mirror 1 to act the surface acoustic wave 3 from top to bottom on the mirror surface 12 of the rearview mirror 1, and the other single-phase unidirectional transducer 2 is provided at the bottom of the rearview mirror 1 to act the surface acoustic wave 3 from bottom to top on the mirror surface 12 of the rearview mirror 1.

[0083] Thus, the top single-phase unidirectional transducer 2 generates surface acoustic waves 3 that propagate towards the bottom of the rearview mirror 1, driving the droplets 4 of the surface acoustic waves 3 to move towards the bottom of the rearview mirror 1, and the bottom single-phase unidirectional transducer 2 generates surface acoustic waves 3 that propagate towards the top of the rearview mirror 1, driving the droplets 4 of the surface acoustic waves 3 to move towards the top of the rearview mirror 1. This effectively removes droplets 4 and dust from the top to the bottom of the mirror surface 12 of the rearview mirror 1, increasing the cleaning area of ​​the rearview mirror 1 and achieving a more thorough cleaning of the mirror surface 12 of the rearview mirror 1.

[0084] This utility model also proposes a rearview mirror cleaning system 1000.

[0085] According to an embodiment of the present invention, a rearview mirror cleaning system 1000 includes an electronic control board 200 and a rearview mirror assembly 100 of any of the above embodiments. The electronic control board 200 is electrically connected to a single-phase unidirectional transducer 2 and is used to control the single-phase unidirectional transducer 2 to generate surface acoustic waves 3.

[0086] Specifically, such as Figure 2 and Figure 3 As shown, the rearview mirror cleaning system 1000 includes an electronic control board 200 and a rearview mirror assembly 100. The electronic control board 200 is electrically connected to a single-phase unidirectional transducer 2, enabling the electronic control board 200 to transmit current and signals with the single-phase unidirectional transducer 2. When cleaning of the rearview mirror 1 is required, the electronic control board 200 can transmit voltage to the single-phase unidirectional transducer 2 to control the single-phase unidirectional transducer 2 to generate surface acoustic waves 3 that propagate in a single direction, thereby driving the droplets 4 to move in a directional manner and improving cleaning efficiency.

[0087] In some embodiments, the rearview mirror cleaning system 1000 further includes a sensing element electrically connected to the electronic control board 200, and the sensing element is used to detect the single-phase unidirectional transducer 2, and the electronic control board 200 is used to control the single-phase unidirectional transducer 2 by controlling the detection result of the sensing element.

[0088] Specifically, the sensing element can be configured as a current sensor, which is electrically connected to the control board 200. That is, the sensing element and the control board 200 can transmit signals or current. The sensing element is used to detect the single-phase unidirectional transducer 2. When droplets 4 are attached to the mirror 12, the resonant frequency of the single-phase unidirectional transducer 2 will change, and the mechanical characteristics of the mirror 12 will change. This will affect the vibration characteristics of the single-phase unidirectional transducer 2, thereby changing the resonant frequency of the single-phase unidirectional transducer 2. The change in the resonant frequency will cause the impedance characteristics of the single-phase unidirectional transducer 2 to change, thereby affecting its current. Thus, the sensing element reflects the cleanliness of the mirror 12 and whether there are stains that need to be cleaned by detecting the current of the single-phase unidirectional transducer 2.

[0089] Therefore, the sensing element can detect the change in the operating current of the single-phase unidirectional transducer 2 in real time, and transmit the detected operating current of the single-phase unidirectional transducer 2 to the control board 200. The control board 200 performs resonant frequency matching based on the received operating current, finds the resonant point that can make the single-phase unidirectional piezoelectric transducer generate the maximum amplitude, and then the control board 200 controls the single-phase unidirectional transducer 2 to generate surface acoustic waves 3 according to the resonant frequency.

[0090] It should be noted that the resonant frequency of the single-phase unidirectional transducer 2 will shift due to factors such as temperature, humidity and aging, which will affect the magnitude of its current. It is necessary to determine the resonant frequency point after the shift. The control board 200 can also determine the resonant frequency point after the shift based on the received operating current in order to improve the energy conversion efficiency of the single-phase unidirectional transducer 2 and find the resonant point that makes the single-phase unidirectional transducer 2 generate the maximum amplitude.

[0091] In practical design, an impedance analyzer can be used to perform precise impedance analysis and circuit matching on the single-phase single-current transducer 2. Combined with the propagation characteristics of surface acoustic waves 3 in solid media, the propagation path of the surface acoustic waves 3 generated by them can be analyzed to determine their unidirectional propagation path and resonant frequency, ensuring that the single-phase unidirectional transducer 2 operates in the optimal state and maximizing the excitation efficiency of surface acoustic waves 3, thereby constructing a system 1000 for use in rearview mirror cleaning.

[0092] Therefore, by precisely controlling the vibration frequency of the single-phase unidirectional transducer 2 to match the natural frequency of the rearview mirror 1 material, a resonance effect is generated. This resonance can significantly enhance the cleaning effect and achieve powerful cleaning and removal of stains. At the same time, the resonant frequency tracking algorithm detects and tracks the resonant frequency change of the single-phase unidirectional transducer 2 in real time and dynamically adjusts the driving frequency of the single-phase unidirectional transducer 2 in real time to ensure that the single-phase unidirectional transducer 2 always maintains the optimal vibration frequency.

[0093] In some embodiments, the electronic control board 200 is connected to the sensing element via the signal acquisition circuit 300.

[0094] Specifically, such as Figure 2 As shown, an ADC current signal acquisition module 301 can be set on the signal acquisition circuit 300, so that the sensing element can detect the working current of the single-phase unidirectional transducer 2 in real time. The ADC current signal acquisition module 301 converts the current signal into a digital signal and transmits it to the control board 200. The control board 200 performs the next control. In the actual design, the control board 200 can use the resonant frequency tracking algorithm to find the resonant point that makes the unidirectional transducer 2 generate the maximum amplitude, so as to complete the resonant frequency matching in a very short time and ensure the effective generation of surface acoustic waves 3.

[0095] In practical design, since the single-phase unidirectional transducer 2 can receive high-frequency signals, it can transmit high-frequency signals, such as input voltage frequency of 1MHz and voltage peak-to-peak value of 100-200Vpp, to the unidirectional transducer 2. This can excite a zero-order symmetrical mode Lamb wave on the mirror surface 12 of the rearview mirror 1. The Lamb wave is a type of surface acoustic wave 3. Its advantages are low propagation path attenuation, wide detection range, and long transmission distance. It can more efficiently act on the liquid droplets 4, snow, frost and other dirt on the mirror surface 12 of the rearview mirror 1, and achieve rapid cleaning of the rearview mirror 1.

[0096] In other embodiments, a PWM generator 400 and an amplifier circuit 500 are sequentially connected between the electronic control board 200 and the single-phase unidirectional transducer 2.

[0097] Specifically, such as Figure 2 As shown, a PWM generator 400 and an amplifier circuit 500 are connected sequentially between the control board 200 and the single-phase unidirectional transducer 2. The PWM generator 400 is connected between the control board 200 and the amplifier circuit 500. The control board 200 can be set as an MCU, which can determine the resonant frequency of the single-phase unidirectional transducer 2 based on the digital signal sent by the ADC current signal acquisition module 301. Then, the control board 200 can drive the PWM generator 400 to output a resonant frequency PWM signal according to the determined resonant frequency of the single-phase unidirectional transducer 2. After that, the resonant frequency PWM signal is amplified and processed by the amplifier circuit 500 to convert the PWM signal into the voltage frequency and voltage peak value required by the single-phase unidirectional transducer 2.

[0098] In some embodiments, the rearview mirror cleaning system 1000 further includes a power supply 600, which is electrically connected to the electronic control board 200 and the amplifier circuit 500, respectively.

[0099] Specifically, such as Figure 2As shown, the rearview mirror cleaning system 1000 also includes a power supply 600, which can be configured as a DC voltage power supply. The power supply 600 is electrically connected to the electronic control board 200 and the amplifier circuit 500 respectively to provide DC voltage to the electronic control board 200 and the amplifier circuit 500.

[0100] In some embodiments, the rearview mirror 1 includes a rearview mirror housing 11 and a mirror surface 12, and the electronic control board 200 is located inside the rearview mirror housing 11 and on the back of the mirror surface 12.

[0101] Specifically, such as Figure 3 As shown, the rearview mirror 1 includes a rearview mirror housing 11 and a mirror surface 12. The mirror surface 12 is positioned facing the rear of the vehicle, and the rearview mirror housing 11 is positioned facing the front of the vehicle. The rearview mirror housing 11 has a cavity to form a mounting cavity. The electronic control board 200 is installed in the mounting cavity and is located on the back of the mirror surface 12. This effectively protects the electronic control board 200 from corrosion by rainwater or other external environmental factors, preventing the electronic control board 200 from malfunctioning. Furthermore, since it is installed inside the rearview mirror housing 11, it does not occupy other space, simplifying the structure and space occupied by the rearview mirror cleaning system 1000.

[0102] This utility model also proposes a vehicle.

[0103] The vehicle according to the present invention includes the rearview mirror cleaning system 1000 of any of the above embodiments.

[0104] The rearview mirror cleaning system 1000 can adapt to cleaning needs under different weather conditions, including rain, snow, and fog. It avoids safety hazards caused by untimely cleaning and ensures that the car rearview mirror 1 can maintain a clear field of vision in various harsh environments. The system has a simple structure and does not require additional equipment support, reducing maintenance and replacement costs caused by equipment failure and improving the system's economy and practicality.

[0105] According to the vehicle of this utility model embodiment, by setting the above-mentioned rearview mirror cleaning system 1000, the rearview mirror 1 can be cleaned quickly and automatically, so that it can always be kept in a clean state, providing the driver with a clear field of vision, thereby improving driving safety.

[0106] Accordingly, the rearview mirror 1 can be cleaned by applying the rearview mirror cleaning system 1000 through the following steps.

[0107] Step 1: Start the rearview mirror cleaning system 1000;

[0108] Turn on the power to the rearview mirror cleaning system 1000 to ensure that the single-phase unidirectional transducer 2 and other components are in normal working condition. At the same time, the sensing element can detect whether there is liquid or stains on the mirror surface 12 of the rearview mirror 1 that need to be cleaned.

[0109] Step 2: Rapid matching of resonant frequencies;

[0110] The current changes during the operation of the unidirectional piezoelectric transducer are captured in real time by the sensing element. The circuit signal is converted into a digital signal by the signal acquisition circuit 300. The resonant frequency tracking algorithm is used to find the resonant point that makes the single-phase unidirectional transducer 2 generate the maximum amplitude, so as to complete the resonant frequency matching in a very short time.

[0111] Step 3: Generation and propagation of surface acoustic waves 3;

[0112] After the single-phase unidirectional transducer 2 completes the resonant frequency matching, it excites unidirectional surface acoustic waves 3 on the mirror surface 12 of the rearview mirror 1, which is a non-piezoelectric substrate. These surface acoustic waves 3 propagate along the non-piezoelectric substrate of the mirror surface 12 and encounter the droplet 4. Due to the absorption and blocking effect of the droplet 4, leakage surface waves 5 are generated inside the droplet 4. After the droplet 4 continuously absorbs the radiation energy of the surface acoustic waves 3, the directional driving of the droplet 4 is realized by utilizing the radiation energy of the surface acoustic waves 3.

[0113] Step 4: Droplet 4-Drive and Cleaning;

[0114] As the surface acoustic wave 3 continues to propagate on the rearview mirror 1, which serves as a non-piezoelectric substrate, the droplets 4 and tiny impurity particles attached to the mirror surface 12 are subjected to periodic forces, causing them to vibrate slightly and gradually lose their adhesion to the substrate. Simultaneously, they move under the influence of gravity and acoustic force. During the process of driving the droplets 4, the unidirectional propagation of the surface acoustic wave 3 excited by the single-phase unidirectional transducer 2 ensures that the droplets 4 move along a preset direction, avoiding chaotic splashing.

[0115] Step 5: System shutdown and automatic detection.

[0116] After cleaning the mirror 12 of the rearview mirror 1, the system automatically shuts down the amplifier circuit 500 and stops the excitation of the surface acoustic wave 3. At the same time, the sensing element continuously monitors the cleaning status of the mirror 12 of the rearview mirror 1. When the sensing element detects new stains or water mist, a new cleaning cycle can be triggered.

[0117] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0118] Although embodiments of the present invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the present invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A rearview mirror assembly, characterized in that, include: Rearview mirror (1); A single-phase unidirectional transducer (2) is used to generate surface acoustic waves (3) and to apply the surface acoustic waves (3) to the mirror surface (12) of the rearview mirror (1).

2. The rearview mirror assembly according to claim 1, characterized in that, The single-phase unidirectional transducer (2) has a wave channel (21) formed inside. The wave channel (21) has a first inner wall (22) and a second inner wall (23) that are relatively distributed. The first inner wall (22) is provided with a first excitation sound wave finger (24), and the second inner wall (23) is provided with a second excitation sound wave finger (25). The first excitation sound wave finger (24) is spaced apart from the second inner wall (23), and the second excitation sound wave finger (25) is spaced apart from the first inner wall (22). The wave channel (21) is further provided with a sound reflection source finger strip (26), which is located in the direction of propagation of the surface acoustic wave (3) of the first excitation sound wave finger strip (24) and the second excitation sound wave finger strip (25), and the sound reflection source finger strip (26) is provided with a sound wave hole.

3. The rearview mirror assembly according to claim 2, characterized in that, The first excitation acoustic wave finger (24) and the second excitation acoustic wave finger (25) are parallel and spaced apart; And / or, there are multiple first excitation acoustic wave fingers (24) and multiple second excitation acoustic wave fingers (25), and the multiple first excitation acoustic wave fingers (24) and multiple second excitation acoustic wave fingers (25) are staggered along the transmission direction of the surface acoustic wave (3); And / or, the length of the first excitation acoustic wave finger (24) protruding toward the second inner wall (23) is the same as the length of the second excitation acoustic wave finger (25) protruding toward the first inner wall (22).

4. The rearview mirror assembly according to claim 3, characterized in that, Multiple first excitation acoustic wave finger strips (24) and multiple second excitation acoustic wave finger strips (25) are distributed in a one-to-one correspondence to form multiple excitation acoustic wave finger strip groups, and each group of excitation acoustic wave finger strips is provided with the acoustic reflection source finger strip (26) on the rear side.

5. The rearview mirror assembly according to claim 4, characterized in that, There are multiple acoustic reflection source fingers (26), and the multiple acoustic reflection source fingers (26) are arranged one-to-one on the rear side of the multiple excitation acoustic wave finger groups.

6. The rearview mirror assembly according to claim 4, characterized in that, The acoustic reflection source finger strip (26) is disposed on the first inner wall (22), and the length of the acoustic reflection source finger strip (26) protruding toward the second inner wall (23) is the same as the length of the first excitation acoustic wave finger strip (24) protruding toward the second inner wall (23); Alternatively, the acoustic reflection source finger (26) is disposed on the second inner wall (23), and the length of the acoustic reflection source finger (26) protruding toward the first inner wall (22) is the same as the length of the second excitation acoustic wave finger (25) protruding toward the first inner wall (22).

7. The rearview mirror assembly according to claim 1, characterized in that, The single-phase unidirectional transducer (2) is located on the top of the rearview mirror (1), and the single-phase unidirectional transducer (2) is used to apply the surface acoustic wave (3) from top to bottom to the mirror surface (12) of the rearview mirror (1). Alternatively, the single-phase unidirectional transducer (2) is located at the bottom of the rearview mirror (1), and the single-phase unidirectional transducer (2) is used to apply the surface acoustic wave (3) from bottom to top to the mirror surface (12) of the rearview mirror (1).

8. The rearview mirror assembly according to claim 1, characterized in that, The single-phase unidirectional transducer (2) is configured in two parts. One single-phase unidirectional transducer (2) is located at the top of the rearview mirror (1) to allow the surface acoustic wave (3) to act on the mirror surface (12) of the rearview mirror (1) from top to bottom. The other single-phase unidirectional transducer (2) is located at the bottom of the rearview mirror (1) to allow the surface acoustic wave (3) to act on the mirror surface (12) of the rearview mirror (1) from bottom to top.

9. A rearview mirror cleaning system, characterized in that, The device includes an electronic control board (200) and a rearview mirror assembly according to any one of claims 1-8, wherein the electronic control board (200) is electrically connected to the single-phase unidirectional transducer (2) and is used to control the single-phase unidirectional transducer (2) to generate surface acoustic waves (3).

10. The rearview mirror cleaning system according to claim 9, characterized in that, It also includes a sensing element, which is electrically connected to the electronic control board (200). The sensing element is used to detect the single-phase unidirectional transducer (2), and the electronic control board (200) is used to control the detection result of the sensing element to control the single-phase unidirectional transducer (2).

11. The rearview mirror cleaning system according to claim 10, characterized in that, The electronic control board (200) and the sensing element are connected through a signal acquisition circuit (300); And / or, a PWM generator (400) and an amplifier circuit (500) are sequentially connected between the electronic control board (200) and the single-phase unidirectional transducer (2).

12. The rearview mirror cleaning system according to claim 11, characterized in that, It also includes a power supply (600), which is electrically connected to the electronic control board (200) and the amplifier circuit (500).

13. The rearview mirror cleaning system according to claim 9, characterized in that, The rearview mirror (1) includes a rearview mirror housing (11) and a mirror surface (12), and the electronic control board (200) is located inside the rearview mirror housing (11) and on the back of the mirror surface (12).

14. A vehicle, characterized in that, The rearview mirror cleaning system includes any one of claims 9-13.

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