Transparent electrostatic ultrasonic transducer and display equipment

Abstract

The invention discloses a transparent electrostatic ultrasonic transducer and a display device, the transducer increases the surface roughness of the surface of a vibrating diaphragm and / or the surface of an insulating layer, so that when light waves reflected from the two interfaces are superposed, the phase relation of the light waves rapidly changes in space, or the light waves are subjected to diffuse reflection, and the surface roughness of the vibrating diaphragm and / or the surface roughness of the insulating layer are / is increased. Therefore, a large-area and bright-color coherent interference pattern cannot be formed. By means of the scheme, the thin film interference condition can be effectively damaged, the transparent electrostatic ultrasonic transducer does not present obvious rainbow stripes under white light, the visual appearance of the transparent electrostatic ultrasonic transducer is improved, therefore, when the transparent electrostatic ultrasonic transducer is integrated with a display screen, no visual interference is generated on display content, user experience is improved, and the transparent electrostatic ultrasonic transducer is particularly suitable for applications with high requirements for visual quality and has wide application prospects. Such as smart phones, tablet personal computers, vehicle-mounted displays and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of directional sound generation, and in particular to a transparent electrostatic ultrasonic transducer and a display device. Background Art

[0002] The main structure of existing transparent electrostatic ultrasonic transducers typically includes a vibrating membrane, a fixed electrode, a micron-scale air gap between the two, an insulating layer, and a support structure that forms the air gap. To achieve good acoustic performance, such as high electromechanical conversion efficiency and sound pressure output, the air gap within the transducer unit must be highly uniform.

[0003] However, when the thickness of the air gap is several times the wavelength of visible light and is very uniform, the inner surface of the vibrating membrane and the insulating layer or the surface of the fixed electrode below will form a structure similar to a Fabry-Perot interferometer. Under the illumination of broadband white light (such as ambient light), light of different wavelengths will constructively or destructively interfere at specific angles and specific air gap thicknesses, resulting in rainbow-colored interference fringes on the transducer surface (i.e., rainbow patterns or an extension of the Newton ring phenomenon), such as Figure 1 Although this rainbow streak is a sign of a uniform air gap, it can severely impact the visual quality and user experience when integrated with a display, making the screen appear greasy or speckled with unnatural colors. This phenomenon is particularly pronounced when the transducer area is large.

[0004] Existing technologies primarily focus on optimizing the transducer's acoustic performance and measuring its structural parameters. However, there is no proven solution for eliminating or mitigating the visual interference rainbow fringes caused by the highly uniform air gap. Therefore, there is an urgent need to develop a technical solution that can effectively eliminate or significantly reduce rainbow fringes on the surface of transparent electrostatic ultrasonic transducers while maintaining their original acoustic performance and transparency to meet the visual requirements of display integration applications. Summary of the Invention

[0005] The object of the present invention is to provide a transparent electrostatic ultrasonic transducer and a display device that can effectively eliminate or significantly reduce rainbow stripes on the surface of the transparent electrostatic ultrasonic transducer while maintaining its original acoustic performance and transparency as much as possible.

[0006] To achieve the above objectives, on the one hand, the present invention provides a transparent electrostatic ultrasonic transducer, comprising a vibration layer, a fixed electrode and multiple support structures, wherein the vibration layer comprises a vibration membrane and a top electrode, and the top electrode is arranged on the surface of the vibration membrane close to the fixed electrode; the fixed electrode comprises a fixed base plate, a bottom electrode and an insulating layer, the bottom electrode is arranged on the surface of the fixed base plate close to the vibration layer, and the insulating layer is arranged on the surface of the bottom electrode close to the vibration layer; the vibration layer and the fixed electrode frame are in contact with each other, the support structure is located between the vibration layer and the fixed electrode, and an air gap is formed between the vibration layer and the fixed electrode under the support of the support structure; the haze and first surface roughness of the lower surface of the vibration membrane close to the top electrode and / or the upper surface away from the top electrode are increased, the haze is 3% to 50%, the first surface roughness is 0.1μm to 1.0μm and less than 10% of the thickness of the vibration membrane, and / or the second surface roughness of the upper surface of the insulating layer close to the air gap is increased, the second surface roughness is 0.05μm to 2.0μm and less than 10% of the thickness of the insulating layer.

[0007] In a preferred embodiment, increasing the haze and first surface roughness of the lower surface of the vibration membrane close to the top electrode and / or the upper surface away from the top electrode includes: forming a first microscopic rough structure or adding a microscopic rough layer on the lower surface and / or upper surface of the vibration membrane.

[0008] In a preferred embodiment, the micro-rough layer includes a light scattering layer, the light scattering layer includes an anti-glare AG layer, and the anti-glare AG layer includes a transparent adhesive layer containing micron-sized transparent particles; and / or the first micro-rough structure is formed by surface treatment of the vibration membrane by physical and / or chemical methods, and the physical and / or chemical methods include one or a combination of any two or more of plasma treatment, plasma etching, chemical etching, mechanical embossing, and mechanical knurling.

[0009] In a preferred embodiment, the vibration membrane is a PET film with a thickness of 5um~500um, the thickness of the anti-glare AG layer is 1um~10um, the micron-sized transparent particles in the anti-glare AG layer include any one or any combination of two or more of silica particles, polymethyl methacrylate microspheres, and polystyrene microspheres, the average particle size range of the micron-sized transparent particles is 1um~10um, the transparent adhesive layer includes an acrylic resin adhesive layer or a polyurethane resin adhesive layer, and / or the plasma treatment includes using plasma to treat the vibration membrane, the processing power is 50W~300W, and the time is 10s~300s.

[0010] In a preferred embodiment, the method of increasing the second surface roughness of the upper surface of the insulating layer close to the air gap includes: forming a second microscopic rough structure on the upper surface of the insulating layer, or changing the preparation process of the insulating layer, and the preparation process includes forming the insulating layer using screen printing or inkjet printing process.

[0011] In a preferred embodiment, the second microscopic roughness is formed by treating the upper surface of the insulating layer in a physical and / or chemical manner, wherein the physical and / or chemical manner includes plasma treatment or chemical etching.

[0012] In a preferred embodiment, in the plasma treatment or chemical etching process, the material of the insulating layer is any one of silicon dioxide, silicon nitride, polyimide, polyparaxylene, SU-8 photoresist, transparent OC photoresist, or any combination of two or more thereof, with a thickness of 0.5 μm to 10 μm; and / or, the plasma treatment includes using plasma to treat the insulating layer, with a processing power of 50 W to 300 W and a time of 30 s to 10 min.

[0013] In a preferred embodiment, in the preparation process, the material of the insulating layer is transparent insulating ink or transparent insulating ink added with nano- or micron-sized transparent fillers, the nano- or micron-sized transparent fillers include silicon dioxide, and / or the mesh size of the screen printing is 200 mesh to 400 mesh, and the thickness of the insulating layer after printing is 1 μm to 15 μm.

[0014] In a preferred embodiment, if the material of the insulating layer is photoresist, the method of forming the second microscopic rough structure on the upper surface of the insulating layer includes exposing and developing the photoresist or adding nano- or micron-sized transparent fillers to the photoresist, and the nano- or micron-sized transparent fillers include silicon dioxide; or performing thermal reflow morphology modification or roughening treatment on the surface of the photoresist.

[0015] On the other hand, the present invention proposes a display device, which includes a display screen and the above-mentioned transparent electrostatic ultrasonic transducer, wherein the transparent electrostatic ultrasonic transducer is located on the outer side of the display screen close to the user side or the inner side away from the user side or is integrated into the display screen.

[0016] Compared with the prior art, the present invention has the following beneficial effects: 1. By increasing the surface roughness of the diaphragm and / or the insulating layer, the present invention causes the phase relationship of light waves reflected from these two interfaces to rapidly change spatially when superimposed, or the light waves to be diffusely reflected, thus preventing the formation of a large-area, vibrantly colored coherent interference pattern. This approach effectively eliminates the conditions for thin-film interference, eliminating the obvious rainbow fringes displayed by the transparent electrostatic ultrasonic transducer under white light and improving its visual appearance.

[0017] 2. The present invention eliminates rainbow stripes and makes it possible for the transparent electrostatic ultrasonic transducer to be integrated with a display screen without causing visual interference to the displayed content, thereby improving the user experience. The invention is particularly suitable for applications with high requirements for visual quality, such as smart phones, tablet computers, and car displays.

[0018] 3. Most of the improved methods proposed in the present invention are based on existing mature thin film processing technologies (such as anti-glare AG coating, plasma treatment, screen printing, etc.), which can be easily integrated into the existing production process of transparent electrostatic ultrasonic transducers, and the cost increase is controllable.

[0019] 4. Under the premise of reasonable control of processing parameters, the impact of the present invention on the core acoustic performance of the transducer (such as resonant frequency and sound pressure level, etc.) and overall transparency can be controlled within an acceptable range. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 Schematic diagram of interference fringes on the surface of an existing transducer; Figure 2 A schematic diagram of the specific structure of a transparent electrostatic ultrasonic transducer (with a microscopic rough layer added to both the upper and lower surfaces of the vibrating membrane) in another embodiment of the present invention; Figure 3 Schematic diagram of the specific structure of a transparent electrostatic ultrasonic transducer (with a microscopic rough layer added to the lower surface of the vibrating membrane) in one embodiment of the present invention; Figure 4 It is a schematic diagram of the stacked structure of the transparent electrostatic ultrasonic transducer and the display screen of the present invention.

[0021] The accompanying drawings are: 10. Transparent electrostatic ultrasonic transducer, 1. Vibration layer, 11. Vibration membrane, 12. Top electrode, 13. Microscopic roughness layer, 2. Fixed electrode, 21. Fixed base plate, 22. Bottom electrode, 23. Insulation layer, 3. Support structure, 4. Air gap, 20. Display screen. DETAILED DESCRIPTION

[0022] The specific embodiments of the present invention are described in detail below, but it should be understood that the protection scope of the present invention is not limited by the specific embodiments.

[0023] Unless expressly stated otherwise, throughout the specification and claims, the term “comprise” or variations such as “include” or “comprising” will be understood to include the stated elements or components but not to exclude other elements or components.

[0024] Combine Figure 2 and Figure 3As shown, a transparent electrostatic ultrasonic transducer disclosed in an embodiment of the present invention includes a vibration layer 1, a fixed electrode 2, and multiple support structures 3. The vibration layer 1 and the fixed electrode 2 are bonded together, the support structure 3 is located between the vibration layer 1 and the fixed electrode 2, and an air gap 4 is formed between the vibration layer 1 and the fixed electrode 2 due to the support of the support structure 3. During operation, the vibration layer 1 vibrates and produces sound under the influence of the DC bias voltage and AC voltage applied between the vibration layer 1 and the fixed electrode 2.

[0025] Specifically, the vibration layer 1 includes a vibrating membrane 11 and a top electrode 12. The top electrode 12 is disposed on the surface of the vibrating membrane 11 near the fixed electrode 2. In implementation, the vibrating membrane 11 is typically a PET (polyethylene terephthalate) film, but can also be replaced with other transparent flexible materials such as PI (polyimide) and PEN (polyethylene naphthalate). The fixed electrode 2 includes a fixed base plate 21, a bottom electrode 22, and an insulating layer 23. The bottom electrode 22 is disposed on the surface of the fixed base plate 21 near the vibration layer 1, and the insulating layer 23 is disposed on the surface of the bottom electrode 22 near the vibration layer 1. In implementation, the fixed base plate 21 can be a glass substrate, and the bottom electrode 22 and the top electrode 12 can be transparent ITO (indium tin oxide) layers.

[0026] Preferably, based on the above-mentioned transparent electrostatic ultrasonic transducer, microscopic irregularities or scattering properties are introduced on the surface of the vibrating membrane 11 and / or the surface of the insulating layer 23 to increase the roughness of these two surfaces, thereby changing the reflection and interference behavior of light at the air gap interface and destroying the conditions for large-area coherent interference. Specifically, a first microscopic roughness structure (not shown) is formed on the lower surface of the vibrating membrane 11 near the top electrode 12 and / or on the upper surface away from the top electrode 12, or a microscopic roughness layer 13 is added, hereinafter referred to as Scheme 1, and / or a second microscopic roughness structure (not shown) is formed on the upper surface of the insulating layer 23 near the air gap 4, hereinafter referred to as Scheme 2.

[0027] Specifically, as in Scheme 1, a first micro-rough structure or micro-rough layer 13 is introduced on one or two surfaces (i.e., the lower surface or the upper surface or both the upper and lower surfaces) of the vibration membrane 11 (usually a PET film), especially the lower surface facing the air gap 4 or the upper surface facing the observer, to increase its haze and first surface roughness, specifically to achieve a surface haze of 3% to 50%, a first surface roughness of 0.1μm to 1.0μm and less than 10% of the thickness of the vibration membrane.

[0028] In a specific embodiment, the vibration film 11 is an optical grade PET film with a thickness of 5 μm to 500 μm. Figure 2 and Figure 3As shown, when a micro-rough layer 13 is added to the lower and / or upper surface of the PET film, the micro-rough layer 13 can be a coated anti-glare AG (Anti-Glare) layer. Specifically, the AG coating can be applied to the surface of the PET film by roller coating, spraying, blade coating, etc., and then cured (e.g., UV curing or thermal curing). Of course, commercially available PET films with pre-fabricated AG layers can also be used.

[0029] The anti-glare AG layer can have a thickness of 1μm to 10μm and typically includes a transparent adhesive layer containing micron-sized transparent particles. These micron-sized transparent particles can be silica (SiO2) microspheres and / or polymer microspheres. The polymer microspheres can be polymethyl methacrylate (PMMA) microspheres, polystyrene (PS) microspheres, or the like, with an average particle size ranging from 1μm to 10μm. The transparent adhesive layer can be an optically transparent resin layer. In practice, the optically transparent resin layer can be made of acrylic resin, polyurethane resin, or the like. In this embodiment, the haze of the PET film surface can range from 3% to 50%, preferably from 5% to 30%. A haze that is too low will not significantly improve rainbow patterns, while a haze that is too high may excessively affect the transparency and display clarity of the PET film. The surface roughness (Ra) of the PET film can range from 0.1μm to 1.0μm and should be less than 10% of the PET film thickness to avoid a significant negative impact on the acoustic performance of the transducer.

[0030] In another specific embodiment, the diaphragm is also an optical-grade PET film with a thickness of 5μm to 500μm. When forming the first microscopic roughness on the lower and / or upper surfaces of the PET film, the surface of the diaphragm can be treated physically and / or chemically to form tiny pits, protrusions, or textures to enhance light scattering. In practice, the physical and / or chemical treatments include one or a combination of two or more of plasma treatment, plasma etching, chemical etching, mechanical embossing, and mechanical knurling. For example, in plasma treatment or plasma etching, the PET film surface can be treated for a short time using a plasma of argon (Ar), oxygen (O2), carbon tetrafluoride (CF4), or a mixture of two or more of these gases to form a nanoscale or micrometer-scale roughness structure. The treatment power can be 50W to 300W, and the treatment time can be 10s to 300s. In chemical etching, the PET film surface can be selectively etched using an appropriate chemical reagent (e.g., hydrofluoric acid). For example, in the mechanical embossing and mechanical knurling methods, the PET film can be embossed by a mold with fine textures.

[0031] Specifically, as in Option 2, the second surface roughness of the upper surface of the insulating layer 23 near the air gap 4 can be increased to achieve a second surface roughness of 0.05μm to 2.0μm, less than 10% of the thickness of the insulating layer. In practice, the topography of the upper surface of the insulating layer 23 can be modified to introduce microscopic height fluctuations, causing the thickness of the air gap 4 to vary rapidly within a small region, thereby disrupting the conditions for forming uniform interference fringes. This can be achieved by forming a second microscopic roughness structure on the upper surface of the insulating layer 23 or by modifying the preparation process of the insulating layer 23.

[0032] In this method, during implementation, the material of the insulating layer 23 can be silicon dioxide (SiO2), silicon nitride (SiN x ), polyimide (PI), polyparaxylene (Parylene), SU-8 photoresist, transparent OC photoresist, transparent insulating ink, or any combination of two or more thereof, with a thickness of 0.5μm to 10μm. When forming the second microscopic rough structure on the upper surface of the insulating layer 23, the upper surface of the insulating layer 23 can be treated by physical and / or chemical methods. During implementation, the physical and / or chemical methods include plasma treatment or chemical etching, that is, the upper surface of the insulating layer 23 is plasma-treated or chemically etched to form the second microscopic rough structure on its surface. For example, in the plasma treatment method, the surface of the insulating layer 23 can be treated for a short time with argon (Ar), oxygen (O2) or carbon tetrafluoride (CF4) or a mixed gas plasma of two or more thereof to form a nanometer-scale or micrometer-scale rough structure; the processing power can be specifically 50W to 500W, and the time is 30s to 10min. In this embodiment, the surface roughness (Ra) of the insulating layer 23 can reach 50nm to 800nm, preferably 100nm to 500nm, which should be sufficient to cause significant local changes in the optical path difference on the visible light wavelength scale (approximately 400nm to 700nm); but the surface roughness of the insulating layer 23 is less than 10% of its thickness to avoid a significant negative impact on the acoustic performance of the transducer.

[0033] For example, in a chemical etching method, an appropriate etching solution and etching time can be selected based on the material of the insulating layer 23 to selectively etch the surface of the insulating layer 23 to achieve the target roughness. The etching solution can be an existing hydrofluoric acid etching solution, and the etching time is determined according to the target roughness, which is not limited by the present invention.

[0034] If photoresist is used as the material of the insulating layer 23 or the supporting structure 3, the surface roughness can be increased by adjusting the exposure and development conditions or adding nano- or micron-sized transparent fillers to the photoresist, wherein the nano- or micron-sized transparent fillers include silicon dioxide; or post-processing the surface of the photoresist, such as using thermal reflow morphology modification and roughening treatment.

[0035] Another example is changing the surface roughness of the insulating layer 23 by changing its preparation process. During implementation, unlike the existing insulating layer 23 that uses processes such as spin coating or evaporation that easily form a smooth surface, the present invention uses preparation processes such as screen printing or inkjet printing to deposit a transparent insulating ink material to form the insulating layer 23. Such processes themselves tend to form a surface with certain microscopic undulations. During implementation, a transparent insulating ink can be used, or a transparent insulating ink with a small amount of nano- or micron-sized transparent filler added to assist in adjusting the roughness of the insulating layer 23. The transparent insulating ink can specifically be a UV-curable or thermally curable ink based on acrylate, epoxy resin, or polyurethane. In the screen printing process, the mesh size of the screen can specifically be 200 to 400 mesh, the thickness of the insulating layer 23 after printing is 1μm to 15μm, and the surface roughness of the formed insulating layer 23 is 0.1μm to 2μm.

[0036] Of course, the various methods in Solution 1 and Solution 2 can be combined and applied according to actual needs to achieve the best rainbow stripe elimination effect and visual experience. For example, a PET film coated with an anti-glare AG layer and a roughened insulating layer 23 can be used at the same time.

[0037] The following three specific embodiments are used to specifically introduce the solution of eliminating rainbow patterns using the transparent electrostatic ultrasonic transducer.

[0038] Example 1

[0039] A transparent electrostatic ultrasonic transducer disclosed in Example 1 of the present invention includes the following steps: The fixed electrode 2 is prepared as follows: the fixed base plate 21 of the fixed electrode 2 is a 0.7 mm thick Corning Gorilla glass substrate, on which a 100 nm thick layer of ITO is deposited by magnetron sputtering as a bottom electrode 22; a 2 μm thick layer of transparent photosensitive polyimide (PSPI) is spin-coated on the bottom electrode 22 as an insulating layer 23; and an array of support pillars with a height of 8 μm, a diameter of 50 μm, and a pitch of 1 mm is fabricated on the insulating layer 23 by coating and photolithography (e.g., using SU-8 photoresist) as a supporting structure 3; the insulating layer 23 and the supporting structure 3 are cured, and the surface of the insulating layer 23 is smooth.

[0040] Preparation of Vibration Layer 1: In Example 1, a 12μm-thick PET film was used with an AG coating on one side. The AG coating consisted of SiO2 particles with an average particle size of 3μm and an acrylic resin adhesive layer, with a thickness of approximately 4μm. The haze of this AG-coated PET film was 15%, and the total light transmittance was >88%. An 80nm-thick layer of ITO was sputtered onto the non-AG surface (i.e., the smooth surface) of the PET film to serve as the top electrode 12.

[0041] Lamination: Cover the vibration layer 1 (with its AG surface facing outward, i.e., the observer direction, or the AG surface facing the air gap) on the fixed electrode 2 with the support structure 3, fix it by edge bonding, and apply appropriate tension to form an air gap 4.

[0042] The transparent electrostatic ultrasonic transducer prepared in Example 1 exhibits no obvious rainbow streaks when observed under fluorescent or LED light, resulting in a clear visual effect. In contrast, if ordinary high-transmittance PET film (with a haze of <1) is used, obvious rainbow streaks are visible.

[0043] Example 2

[0044] The preparation of the fixed base plate 21 and bottom electrode 22 of a transparent electrostatic ultrasonic transducer disclosed in Example 2 of the present invention is similar to that of Example 1 and is not further described here. Unlike Example 1, the insulating layer 23 in this embodiment is prepared by depositing a 3μm-thick SiO2 layer on the bottom electrode 22 via PECVD as the insulating layer 23. The fixed base plate 21 with the insulating layer 23 is placed in a reactive ion etching (RIE) apparatus, and a CF4 and O2 mixture (e.g., a 4:1 ratio with a total flow rate of 50 sccm) is introduced. Under conditions of RF power of 150W and pressure of 10Pa, a microscopic roughness is formed on the SiO2 surface, with an average surface roughness (Ra) of approximately 200nm.

[0045] Then, a support column array with a height of 8 μm, a diameter of 50 μm, and a pitch of 1 mm is fabricated on the roughened insulating layer 23 by a photolithography process (eg, using SU-8 photoresist) as the support structure 3 .

[0046] Preparation of the vibration layer 1: In Example 2, a conventional high-transmittance PET film was selected. The thickness of the PET film was 12 μm, the haze of the PET film was less than 1%, and the total transmittance was greater than 88%. An 80 nm thick ITO layer was sputtered on one side of the PET film as the top electrode 12.

[0047] Lamination: As in Example 1, the vibration layer 1 (top electrode 12 facing the air gap) is covered on the fixed electrode 2 with the support structure 3 and the roughened insulating layer 23, fixed by edge bonding, and appropriate tension is applied to form an air gap 4.

[0048] The rainbow streaks on the surface of the transparent electrostatic ultrasonic transducer prepared in Example 2 were significantly reduced compared to the device without roughening of the insulating layer. If the plasma treatment parameters are further optimized or combined with a slight atomization treatment of the vibrating membrane, the rainbow streaks can be basically eliminated.

[0049] Example 3

[0050] The transparent electrostatic ultrasonic transducer disclosed in Example 3 of the present invention has the same preparation as that of Example 1 for the fixed base plate 21 and the bottom electrode 22, which will not be described in detail here. Unlike Examples 1 and 2, the preparation process of the insulating layer 23 and the support structure 3 in this embodiment is as follows: a 300-mesh screen is used to directly print a pattern including the insulating layer 23 pattern and the support structure 3 on the bottom electrode 22 through a screen printing process. The design thickness of the insulating layer 23 area is 3μm, and the design height of the support structure 3 area is 10μm (achieved by multiple overprinting or using a thick screen). UV curing is then performed, and the surface of the insulating layer 23 formed by screen printing itself has a certain microscopic unevenness, for example, the roughness Ra is in the range of 0.2μm to 1μm.

[0051] Preparation and lamination of the vibration layer 1: Same as in Example 2, and will not be described in detail here.

[0052] The transparent electrostatic ultrasonic transducer prepared in this embodiment 3 effectively suppresses the generation of rainbow stripes due to the microscopic unevenness of the surface of the insulating layer 23 and the side wall of the supporting structure 3. This method simplifies the preparation steps of the supporting structure 3 and the insulating layer 23.

[0053] Combine Figure 4 As shown, the present invention also discloses a display device, which includes a display screen 20 and the above-mentioned transparent electrostatic ultrasonic transducer 10, wherein the transparent electrostatic ultrasonic transducer 10 is located on the outer side of the display screen 20 close to the user side or the inner side away from the user side or is integrated into the display screen 20.

[0054] The advantages of the present invention are as follows: 1. By increasing the surface roughness of the diaphragm and / or the insulating layer, the phase relationship of the light waves reflected from these two interfaces changes rapidly in space when superimposed, or the light waves are diffusely reflected, preventing the formation of a large-area, vibrant coherent interference pattern. This approach effectively eliminates the conditions for thin-film interference, eliminating the obvious rainbow fringes exhibited by the transparent electrostatic ultrasonic transducer under white light, thereby improving its visual appearance. 2. By eliminating the rainbow fringes, the present invention eliminates visual interference with the displayed content when the transparent electrostatic ultrasonic transducer is integrated with a display screen, enhancing the user experience and making it particularly suitable for applications requiring high visual quality, such as smartphones, tablets, and in-vehicle displays. 3. The improved methods proposed in the present invention are largely based on existing, mature thin-film processing technologies (such as anti-glare AG coating, plasma treatment, and screen printing), making them easily integrated into the existing transparent electrostatic ultrasonic transducer production process with manageable cost increases. 4. By properly controlling the processing parameters, the present invention can maintain an acceptable impact on the transducer's core acoustic properties (such as resonant frequency and sound pressure level) and overall transparency.

[0055] The foregoing descriptions of specific exemplary embodiments of the present invention are for purposes of illustration and description. These descriptions are not intended to limit the invention to the precise forms disclosed, and it is apparent that many variations and modifications are possible in light of the foregoing teachings. The exemplary embodiments have been selected and described for the purpose of explaining the specific principles of the invention and their practical application, thereby enabling those skilled in the art to realize and utilize a variety of exemplary embodiments of the invention and various options and modifications. The scope of the invention is intended to be defined by the claims and their equivalents.

Claims

1. A transparent electrostatic ultrasonic transducer, characterized in that: The transparent electrostatic ultrasonic transducer includes a vibration layer, a fixed electrode, and multiple support structures. The vibration layer includes a vibration membrane and a top electrode, and the top electrode is arranged on the surface of the vibration membrane close to the fixed electrode; the fixed electrode includes a fixed base plate, a bottom electrode, and an insulating layer, and the bottom electrode is arranged on the surface of the fixed base plate close to the vibration layer, and the insulating layer is arranged on the surface of the bottom electrode close to the vibration layer; the vibration layer and the fixed electrode frame are in contact with each other, and the support structure is located between the vibration layer and the fixed electrode, and an air gap is formed between the vibration layer and the fixed electrode due to the support of the support structure; Increase the haze and first surface roughness of the lower surface of the vibration membrane close to the top electrode and / or the upper surface away from the top electrode, the haze is 3%~50%, the first surface roughness is 0.1μm~1.0μm and less than 10% of the thickness of the vibration membrane, and / or increase the second surface roughness of the upper surface of the insulating layer close to the air gap, the second surface roughness is 0.05μm~2.0μm and less than 10% of the thickness of the insulating layer.

2. The transparent electrostatic ultrasonic transducer according to claim 1, characterized in that: Increasing the haze and first surface roughness of the lower surface of the vibration membrane close to the top electrode and / or the upper surface away from the top electrode includes: forming a first microscopic roughness structure or adding a microscopic roughness layer on the lower surface and / or the upper surface of the vibration membrane.

3. The transparent electrostatic ultrasonic transducer according to claim 2, characterized in that: The microscopic rough layer includes a light scattering layer, the light scattering layer includes an anti-glare AG layer, and the anti-glare AG layer includes a transparent adhesive layer containing micron-sized transparent particles; and / or, The first microscopic rough structure is formed by treating the surface of the vibration membrane by physical and / or chemical means, wherein the physical and / or chemical means include one or a combination of any two or more of plasma treatment, plasma etching, chemical etching, mechanical embossing, and mechanical knurling.

4. The transparent electrostatic ultrasonic transducer according to claim 3, characterized in that: The vibration membrane is a PET film with a thickness of 5 μm to 500 μm, the anti-glare AG layer has a thickness of 1 μm to 10 μm, the micron-sized transparent particles in the anti-glare AG layer include any one or any combination of two or more of silica particles, polymethyl methacrylate microspheres, and polystyrene microspheres, and the average particle size of the micron-sized transparent particles ranges from 1 μm to 10 μm, and the transparent adhesive layer includes an acrylic resin adhesive layer or a polyurethane resin adhesive layer; and / or, The plasma treatment includes treating the vibration membrane with plasma, with a treatment power of 50W to 300W and a treatment time of 10s to 300s.

5. The transparent electrostatic ultrasonic transducer according to claim 1, characterized in that: The method of increasing the second surface roughness of the upper surface of the insulating layer close to the air gap includes: forming a second microscopic roughness structure on the upper surface of the insulating layer, or changing the preparation process of the insulating layer, wherein the preparation process includes forming the insulating layer using a screen printing or inkjet printing process.

6. The transparent electrostatic ultrasonic transducer according to claim 5, characterized in that: The second microscopic roughness structure is formed by treating the upper surface of the insulating layer in a physical and / or chemical manner, wherein the physical and / or chemical manner includes plasma treatment or chemical etching.

7. The transparent electrostatic ultrasonic transducer according to claim 6, characterized in that: In the plasma treatment or chemical etching process, the material of the insulating layer is any one of silicon dioxide, silicon nitride, polyimide, parylene, SU-8 photoresist, and transparent OC photoresist, or any combination of two or more thereof, with a thickness of 0.5 μm to 10 μm; and / or, The plasma treatment includes treating the insulating layer with plasma, with a treatment power of 50W to 300W and a treatment time of 30s to 10min.

8. The transparent electrostatic ultrasonic transducer according to claim 5, characterized in that: In the preparation process, the material of the insulating layer is transparent insulating ink or transparent insulating ink added with nanometer or micrometer-sized transparent fillers, and the nanometer or micrometer-sized transparent fillers include silicon dioxide; and / or, The mesh number of the screen printing is 200-400 meshes, and the thickness of the insulating layer after printing is 1 μm-15 μm.

9. The transparent electrostatic ultrasonic transducer according to claim 5, characterized in that: If the material of the insulating layer is photoresist, the method of forming the second microscopic rough structure on the upper surface of the insulating layer includes exposing and developing the photoresist or adding nano- or micron-sized transparent fillers to the photoresist, and the nano- or micron-sized transparent fillers include silicon dioxide; or performing thermal reflow morphology modification or roughening treatment on the surface of the photoresist.

10. A display device, characterized in that: It comprises a display screen and the transparent electrostatic ultrasonic transducer according to any one of claims 1 to 9, wherein the transparent electrostatic ultrasonic transducer is located on the outer side of the display screen close to the user side or the inner side away from the user side, or is integrated into the display screen.

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