A highly reliable directional sound - emitting screen and its manufacturing process

Abstract

The present invention discloses a highly reliable directional sound - emitting screen and its manufacturing process, which includes a vibration layer, a non - vibration layer, and a pattern layer. The vibration layer includes a first conductive layer, and the non - vibration layer includes a second conductive layer and a third conductive layer; during operation, a DC voltage is connected between the second conductive layer and the third conductive layer, and an AC voltage is connected between the first conductive layer and the second conductive layer or between the first conductive layer and the third conductive layer. By separating the original DC and AC that drive the directional sound - emitting screen to work, and first introducing DC to conduct the charges generated by air ionization, the present invention greatly reduces the influence of the charges generated by air ionization on the air partial pressure, and thus can improve the reliability and sound pressure of the directional sound - emitting screen.

Description

Technical Field

[0001] The present invention relates to the technical field of directional sound emission, and particularly relates to a highly reliable directional sound emission screen and a preparation process thereof. Background Art

[0002] An electrostatic thin film ultrasonic transducer, also known as a capacitive thin film ultrasonic transducer, uses the electrostatic force generated by upper and lower electrodes to drive the vibration of a thin film, thereby radiating ultrasonic waves.

[0003] A common structure of an electrostatic thin film ultrasonic transducer generally includes a vibration substrate layer, a top electrode, a pattern layer, an insulating layer, a bottom electrode, and a non-vibration substrate layer, etc., which are arranged in sequence from top to bottom. An air gap is formed between the top electrode and the insulating layer. A DC bias voltage Vdc and an AC voltage Vac are applied between the top electrode and the bottom electrode to drive the vibration substrate layer to vibrate and generate sound.

[0004] However, when the applied voltage increases, the air in the air gap will be ionized. The ionization will increase the conductivity of the air, resulting in a decrease in the partial pressure of the air, and further leading to a decrease in the ultrasonic sound pressure radiated by the electrostatic thin film ultrasonic transducer, thus reducing the performance of the transducer.

[0005] Therefore, how to reduce the influence of air ionization on the reliability and sound pressure of the electrostatic thin film ultrasonic transducer is a problem to be solved. Summary of the Invention

[0006] The purpose of the present invention is to provide a highly reliable directional sound emission screen and a preparation process thereof, which can effectively reduce the influence of air ionization on the reliability and sound pressure of the directional sound emission screen.

[0007] To achieve the above purpose, on the one hand, the present invention provides a highly reliable directional sound emission screen, including:

[0008] A vibration layer, the vibration layer includes a vibration substrate layer and a first conductive layer, and the first conductive layer is formed entirely on the surface of the vibration substrate layer close to the non-vibration layer;

[0009] A non-vibration layer, which is attached to the frame of the vibration layer. The non-vibration layer includes a non-vibration substrate layer, a second conductive layer, and a third conductive layer. The second conductive layer is formed entirely on the surface of the non-vibration substrate layer close to the vibration layer, and the third conductive layer is formed entirely on the surface of the second conductive layer close to the vibration layer and is insulated from the second conductive layer by a first insulating layer. The first conductive layer and the third conductive layer are insulated from each other by a second insulating layer;

[0010] The pattern layer is located between the first conductive layer and the third conductive layer. After the vibration layer is attached to the non-vibration layer frame, an air gap required for the vibration layer to vibrate up and down to generate sound is formed between the vibration layer and the non-vibration layer through the pattern layer. The pattern layer is a plurality of insulating units arranged at intervals;

[0011] During operation, first, a DC voltage is applied between the second conductive layer and the third conductive layer to export the charges generated by air ionization. Then, an AC voltage is applied between the first conductive layer and the second conductive layer or between the first conductive layer and the third conductive layer. The AC voltage ensures the generation of an electric field to drive the normal vibration of the vibration layer.

[0012] In a preferred embodiment, the sheet resistance of the third conductive layer is greater than that of the first conductive layer.

[0013] In a preferred embodiment, the second insulating layer is a screen-printed ink layer, a boron nitride coating, a nano-aluminum oxide coating, or a nano-aluminum oxide coating.

[0014] In a preferred embodiment, the boron nitride coating, the nano-aluminum oxide coating, or the nano-aluminum oxide coating is formed by a magnetron sputtering process.

[0015] In a preferred embodiment, each insulating unit includes a plurality of insulating bumps arranged in a square pattern and the sides of the square are parallel to the sides of the corresponding non-vibration base layer or the vibration base layer. The plurality of insulating units are arranged in an array to form a plurality of array units.

[0016] In a preferred embodiment, a support point is provided at the center of each array unit. The support point is a single point or a multi-point structure, and the height of the support point is less than the height of the insulating bump; or the conductive layer corresponding to the center of each array unit is removed to form a non-conductive layer portion.

[0017] In a preferred embodiment, the height of the support point is 2um - 4um, the height of the insulating bump is 7um - 12um, and the distance between adjacent two array units is 2.2um - 2.8um.

[0018] In a preferred embodiment, the pattern layer is fixed to the second insulating layer or the first conductive layer through an adhesive layer. The adhesive layer is a plurality of spaced adhesive unit structures corresponding to the structure of the pattern layer or is a whole-surface shape.

[0019] In a preferred embodiment, a waterproof layer is further provided on the outermost surface of the vibration layer away from the non-vibration layer, and the thickness of the waterproof layer is 1um - 10um.

[0020] On the other hand, the present invention provides a preparation process for a directional sound emission screen, where the directional sound emission screen is the above-mentioned directional sound emission screen, and the preparation process includes:

[0021] S1, preparing a vibration layer, including forming a first conductive layer on the entire surface of the vibration substrate layer close to the non-vibration layer;

[0022] S2, preparing a non-vibration layer, including forming a second conductive layer on the entire surface of the non-vibration substrate layer close to the vibration layer, forming the first insulating layer on the entire surface of the second conductive layer close to the vibration layer and curing it, and after curing, forming the third conductive layer on the entire surface of the first insulating layer close to the vibration layer, and then forming the second insulating layer on the entire surface of the third conductive layer close to the vibration layer;

[0023] S3, forming a pattern layer on the surface of the first conductive layer close to the non-vibration layer or on the surface of the second insulating layer close to the vibration layer;

[0024] S4, bonding the frames of the vibration layer and the non-vibration layer, tensioning the vibration layer after bonding, and applying a DC voltage between the first conductive layer and the second conductive layer and curing until the bonding between the vibration layer and the non-vibration layer is firm.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1. By separating the original DC and AC that drive the directional sound emission screen to work, and first introducing DC to export the charges generated by air ionization, the present invention greatly reduces the influence of the charges generated by air ionization on the air partial pressure, and thus can improve the reliability and sound pressure of the directional sound emission screen.

[0027] 2. By readjusting the pattern arrangement and spacing of the pattern layer, on the one hand, it is convenient for the printing of the pattern layer, and on the other hand, it can also increase the bonding area between the pattern layer and the vibration layer or the non-vibration layer, making the fixation between the vibration layer and the non-vibration layer stable and also making the tension on the vibration layer spread evenly, which is beneficial to improving the reliability of the formed directional sound emission screen.

[0028] 3. By setting a support point or a non-conductive layer part at the center of each array unit of the pattern layer, the present invention can suppress the problem of increased distortion caused by the collision between the vibration layer and the non-vibration layer at the maximum amplitude of each array unit, and further prevent the reliability failure problem. Description of the Drawings

[0029] Figure 1 It is a schematic structural diagram of the directional sound emission screen of one embodiment of the present invention;

[0030] Figure 2 It is a schematic arrangement structure diagram of the pattern layer of the present invention;

[0031] Figure 3 It is a schematic flow chart of the preparation process of the directional sound emission screen of the present invention.

[0032] The attached drawing reference numerals are:

[0033] 1. Vibration layer, 11. Vibration substrate layer, 12. First conductive layer, 13. First edge trace, 2. Non-vibration layer, 21. Non-vibration substrate layer, 22. Second conductive layer, 23. First insulating layer, 24. Third conductive layer, 25. Second insulating layer, 26. Second edge trace, 27. Third edge trace, 28. Load, 3. Pattern layer, 31. Insulating unit, 32. Insulating bump, 33. Array unit, 34. Support point, 4. Waterproof layer, 5. Adhesive layer. Detailed implementation manners

[0034] The following describes in detail the specific implementation manners of the present invention, but it should be understood that the protection scope of the present invention is not limited by the specific implementation manners.

[0035] Unless otherwise clearly stated, throughout the specification and claims, the term "comprising" or its variations such as "including" or "having" etc. will be understood to include the stated elements or components, without excluding other elements or other components.

[0036] Combined with Figure 1 As shown, a highly reliable directional sound emission screen disclosed by the present invention includes a vibration layer 1, a non-vibration layer 2 and a pattern layer 3. Among them, the borders of the vibration layer 1 and the non-vibration layer 2 are fitted together. By separating the direct current and alternating current that originally drive the directional sound emission screen to work, and first introducing the direct current to export the charges generated by air ionization, the present invention greatly reduces the influence of the charges generated by air ionization on the air partial pressure, and thus can improve the reliability and sound pressure of the directional sound emission screen.

[0037] The vibration layer 1 serves as an acoustic vibration layer, which specifically includes a vibration base layer 11 and a first conductive layer 12. In this embodiment, the vibration base layer 11 can be realized by a flexible film, such as a PET film. The first conductive layer 12 is formed on the entire surface of the vibration base layer 11 close to the non-vibration layer 2. During implementation, the first conductive layer 12 can be realized by high transmittance materials such as nano silver, indium tin oxide, metal mesh, carbon nanotubes or graphene, or can also be a non-transparent conductive material: such as copper or copper-doped oxide or silver or gold. The lower its sheet resistance, the higher the overall sound generation efficiency of the directional sound screen. The sheet resistance is preferably selected to be below 10 ohms. Additionally, in order to further improve the conductivity of the first conductive layer 12, a first edge trace 13 can be added at least at one edge of the surface of the first conductive layer 12 close to the non-vibration layer 2. During implementation, the first edge trace 13 is also realized by copper or copper-doped oxide or silver or gold.

[0038] The non-vibration layer 2 serves as a non-vibration substrate layer, which specifically includes a non-vibration base layer 21, a second conductive layer 22, a first insulating layer 23, a third conductive layer 24 and a second insulating layer 25. Among them, the second conductive layer 22 is formed on the entire surface of the non-vibration base layer 21 close to the vibration layer 1. Preferably, in order to improve the conductivity of the second conductive layer 23, a second edge trace 26 can be added at least at one edge of the surface of the second conductive layer 23 close to the vibration layer 1. Similarly, during implementation, the second edge trace 26 is also realized by copper or copper-doped oxide or silver or gold.

[0039] Preferably, different from the existing non-vibration layer, the present invention adds a conductive layer, namely the third conductive layer 24, on the non-vibration layer 2. Specifically, the first insulating layer 23 is formed on the entire surface of the second conductive layer 22 close to the vibration layer 1 and covers the second edge trace 26. The third conductive layer 24 is formed on the entire surface of the first insulating layer 23 close to the vibration layer 1 and is insulated from the second conductive layer 22 through the first insulating layer 23. Similarly, in order to improve the conductivity of the third conductive layer 24, a third edge trace 27 can be added at least at one edge of the surface of the third conductive layer 24 close to the vibration layer 1. Similarly, during implementation, the third edge trace 27 is also realized by copper or copper-doped oxide or silver or gold. During implementation, in order to avoid breakdown between the first conductive layer 12 and the third conductive layer 24, the sheet resistance of the third conductive layer 24 is much greater than that of the first conductive layer 12. In one implementation case, the sheet resistance of the third conductive layer 24 is several hundred ohms to several thousand ohms, while the sheet resistance of the first conductive layer 12 and the second conductive layer 22 is several ohms to several tens of ohms.

[0040] The second insulating layer 25 is formed entirely on the surface of the third conductive layer 24 close to the vibration layer 1 and covers the third edge trace 27, which is used to insulate and isolate the first conductive layer 12 and the third conductive layer 24 after the vibration layer 1 and the non-vibration layer 2 are edge-bonded, and also to avoid breakdown between the first conductive layer 12 and the third conductive layer 24. Preferably, in implementation, the second insulating layer 25 can be an existing screen printing ink layer or a boron nitride coating, a nano-aluminum oxide coating or an AO-NPs nano-aluminum oxide coating. In implementation, the boron nitride coating, the nano-aluminum oxide coating and the AO-NPs nano-aluminum oxide coating can be formed by a magnetron sputtering process, such as the PVD (Physical Vapor Deposition) magnetron sputtering method. Theoretically speaking, the thicker the thickness of the second insulating layer 25, the greater its density, and the denser it is, the more it can inhibit Schottky emission, reduce charge injection, and prevent breakdown. In implementation, the thickness of the second insulating layer 25 can range from dozens of nm to thousands of nm.

[0041] During operation, in a specific embodiment, a DC voltage is applied between the second conductive layer 22 and the third conductive layer 24. First, the DC is applied to conduct the charges generated by air ionization, and then an AC voltage Vdc is applied between the first conductive layer 12 and the second conductive layer 22 or between the first conductive layer 12 and the third conductive layer 24. The AC voltage Vdc ensures the generation of an electric field to drive the normal vibration of the vibration layer 1.

[0042] In addition, preferably, a waterproof layer 4 is further provided on the outermost surface of the vibration layer 1 away from the non-vibration layer 2, which can prevent the vibration layer 1 from absorbing water and becoming soft in a high-temperature and high-humidity environment, resulting in a smaller distance between the electrodes of the vibration layer and the non-vibration layer, a larger electric field strength, and thus increased polarization. In implementation, the thickness of the waterproof layer 4 can be 1um - 10um.

[0043] Preferably, in this embodiment, the pattern layer 3 is located between the first conductive layer 12 and the third conductive layer 24. After the vibration layer 1 and the non-vibration layer 2 are edge-bonded, an air gap (not shown in the figure) for the vibration layer 1 to vibrate up and down to generate sound is formed between the vibration layer 1 and the non-vibration layer 2 through the pattern layer 3. In implementation, the pattern layer 3 can be formed on the surface of the first conductive layer 12 close to the non-vibration layer 2, or on the surface of the second insulating layer 25 close to the vibration layer 1. The pattern layer 3 is specifically a plurality of spaced insulating units 31.

[0044] In this embodiment, combined with Figure 3As shown, each insulating unit 31 specifically includes a plurality of insulating protrusions 32 arranged in a square and the sides of the square are parallel to the sides of the corresponding non-vibration substrate layer 21 or the sides of the vibration substrate layer 11, and the plurality of insulating units 31 are arranged in an array and arranged to form a plurality of array units 33. The present invention readjusts the pattern arrangement of the pattern layer 3 to be parallel to the sides of the vibration substrate layer 11 or the sides of the non-vibration substrate layer 21, which can facilitate the printing of the pattern layer 3 on the one hand, and can also make the tension on the vibration layer 1 evenly diffused on the other hand, which is conducive to improving the reliability of the formed directional sound screen.

[0045] In addition, more preferably, the present invention sets a support point 34 at the center of each array unit 33, and the support point 34 can be a single point or a multi-point structure, and the height of the support point 34 is less than the height of the insulating bump 32. In a specific embodiment, the height of the support point 34 is 2um~4um, the height of the insulating bump 32 is 7um~12um, and the spacing between two adjacent array units 33 (the spacing here is the distance between the centers of two adjacent array units 33) is 2.2um~2.8um, and in a specific embodiment, the nozzle used in the printing process of the pattern layer 3 is: Konica 1024, the nozzle width is 72mm, and the nozzle is 27um in diameter. Figure 2 As shown in the figure, the spacing L1 between two adjacent insulating units 31 in the horizontal direction is 3.4931mm, the longitudinal height L2 of each insulating unit 31 is 141um, and the distance L3 from the center of the supporting point 34 to the center of the adjacent insulating unit 31 is 2.47mm, which can ensure that the bonding area of ​​each insulating unit 31 is maximized. Alternatively, when implementing, the conductive layer corresponding to the center of each array unit 33 (the conductive layer here refers to the first conductive layer 12 and / or the second conductive layer 22) is removed (when implementing, etching or laser light process can be used to achieve), forming a non-conductive layer portion, when implementing, the non-conductive layer portion can be a single solid circle or a hollow ring, and the non-conductive layer portion can be a single point or a single cluster of multiple points. Because, in the reliability failure model, a high probability failure model is: The film material corresponding to the maximum amplitude has the largest deformation due to long-term vibration. As the working time increases, the film material at this position will contact and collide with the non-vibration layer at the earliest time. The collision will cause noise, higher distortion, and reliability failure. In addition, if the diaphragm is completely in contact with the substrate, the depression at the contact point will also cause visual difference, and the overall diaphragm will show regular or flaky collapse. The present invention can avoid the collapse phenomenon by setting a support point 34 at the center of each array unit 33 of the pattern layer 3, and can suppress the increase in distortion caused by the collision between the vibration layer 1 and the non-vibration layer 2 at the maximum amplitude of each array unit 33, thereby causing reliability failure problems; after the non-conductive layer portion is set, the vibration layer 1 corresponding to this portion will not be affected by the electric field force and will be reduced, which can prevent the occurrence of sound touch failure at this portion between the vibration layer 1 and the non-vibration layer 2.

[0046] In addition, the pattern layer 3 is fixed to the second insulating layer 25 or the first conductive layer 12 through the adhesive layer 5. During implementation, the adhesive layer 5 is a plurality of spaced adhesive unit structures corresponding to the structure of the pattern layer 3 or is in a whole-surface shape. In a specific embodiment, the pattern layer 3 is fixed to the second insulating layer 25 through adhesive points. Specifically, the adhesive points can be formed on the surface of the second insulating layer 25 close to the first conductive layer 12, and the setting positions of the adhesive points on the second insulating layer 25 correspond to the positions of the pattern layer 3 on the vibrating substrate layer 11, that is, each adhesive point corresponds to an insulating bump 32, or an adhesive point is provided on each insulating bump 32 on the pattern layer 3. The height of the adhesive points is preferably as small as possible, preferably 1um - 2um. In the present invention, the pattern layer 3 is fixed to the second insulating layer 25 or the first conductive layer 12, so that after the non-vibrating layer 2 and the vibrating layer 1 are attached, a stable vibrating unit can be formed. In this way, the vibrating layer 1 will not be separated from the non-vibrating layer 2 when vibrating up and down, thereby eliminating the ineffective vibration distance of the vibrating layer 1. This can not only reduce the sound distortion of the entire directional sound screen (in a specific embodiment, the design of the adhesive points can effectively reduce the total harmonic distortion THD at 1KHz from 20% to less than 5%), but also reduce the driving power of the entire product and improve the reliability. During implementation, the adhesive points can be formed on the second insulating layer 25 or the first conductive layer 12 through a printing process or a dispensing process. The printing process includes high-precision 3D printing or non-3D printing. In other alternative embodiments, the pattern layer 3 can also be fixed to the second insulating layer 25 or the first conductive layer 12 through an adhesive layer (not shown in the figure).

[0047] Combined Figure 3 As shown, the present invention also discloses another preparation process for a highly reliable directional sound screen, which mainly includes the following steps:

[0048] S1, preparing the vibrating layer 1, including forming the first conductive layer 12 on the entire surface of the vibrating substrate layer 11 close to the non-vibrating layer 2.

[0049] Specifically, during implementation, the vibrating substrate layer 11 can be a PET film. The first conductive layer 12 is formed on the surface of the PET film by magnetron sputtering. Then, a whole-surface wiring (the wiring material can be copper) is formed on the surface of the first conductive layer 12 by magnetron sputtering, and the first edge wiring 13 is etched out through exposure and development.

[0050] S2. Prepare the non-vibrating layer 2, including forming a second conductive layer 22 over the entire surface of the non-vibrating substrate layer 21 close to the vibrating layer 1, forming a first insulating layer 23 over the entire surface of the second conductive layer 22 close to the vibrating layer 1 and curing it, and after curing, forming a third conductive layer 24 over the entire surface of the first insulating layer 23 close to the vibrating layer 1, and then forming a second insulating layer 25 over the entire surface of the third conductive layer 24 close to the vibrating layer 1.

[0051] Specifically, during implementation, the non-vibrating substrate layer 21 can be glass. The second conductive layer 22 is formed on the glass surface by magnetron sputtering, and then a whole-surface trace (the trace material can be copper) is made on the surface of the second conductive layer 22 by magnetron sputtering, and then the second edge trace 26 is etched out through exposure, development, and etching. Then, the first insulating layer 23 is coated over the entire surface of the second conductive layer 22, and after coating, the first insulating layer 23 is cured by UV curing or heat curing. After curing, the third conductive layer 24 is formed on the surface of the first insulating layer 23 by magnetron sputtering, and then a whole-surface trace (the trace material can be copper) is made on the surface of the third conductive layer 24 by magnetron sputtering, and then the third edge trace 27 is etched out through exposure, development, and etching; then, the second insulating layer 25 (the material can be inorganic compound boron nitride or AO-NPs alumina nanoparticle composite material) is formed on the surface of the third conductive layer 24 by magnetron sputtering to form the non-vibrating layer 2.

[0052] S3. Form a pattern layer 3 on the surface of the first conductive layer 12 close to the non-vibrating layer 2 or on the surface of the second insulating layer 25 close to the vibrating layer 1.

[0053] Specifically, during implementation, the pattern layer 3 can be spray-printed on the surface of the second insulating layer 25 or the first conductive layer 12, and then the adhesive layer 5 is spray-printed on the pattern layer 3.

[0054] S4. Bond the frames of the vibrating layer 1 and the non-vibrating layer 2 together. After bonding, tension the vibrating layer 1, and apply a DC voltage between the first conductive layer 12 and the second conductive layer 22 and cure until the bonding between the vibrating layer 1 and the non-vibrating layer 2 is firm.

[0055] Specifically, during implementation, the non-vibrating layer 2 is bonded to the vibrating layer 1. Tension is required for the vibrating layer 1 during bonding. Pass a DC current to ensure Coulomb attraction between the vibrating layer 1 and the non-vibrating layer 2, and at the same time, cure the in-plane adhesive layer 5 by UV to fully ensure firm bonding between the vibrating layer 1 and the non-vibrating layer 2 into one body.

[0056] In a specific embodiment, the thickness of the vibrating substrate layer 11 is 100um - 125um, the thickness of the waterproof layer 4 is 1um - 10um, the thickness of the adhesive layer 5 is 1um - 2um, the height of the insulating bumps 32 of the pattern layer 3 is 7um - 12um, and the distance between the array units 33 of the pattern layer 3 is 2.2mm - 2.8mm.

[0057] The advantages of the present invention are as follows: 1. By separating the direct current and alternating current that originally drive the directional sound screen to work, and first introducing direct current to conduct the charges generated by air ionization, the influence of the charges generated by air ionization on air partial pressure is greatly reduced, thereby improving the reliability and sound pressure of the directional sound screen. 2. By readjusting the pattern arrangement and spacing of the pattern layer, on the one hand, it is convenient for the printing of the pattern layer, and on the other hand, it can also increase the bonding area between the pattern layer and the vibration layer or non-vibration layer, making the fixation between the vibration layer and the non-vibration layer stable and also making the tension on the vibration layer spread evenly, which is beneficial to improving the reliability of the formed directional sound screen. 3. By setting a support point or a non-conductive layer portion at the center of each array unit of the pattern layer, the problem of increased distortion caused by the collision between the vibration layer and the non-vibration layer at the maximum amplitude of each array unit and the resulting reliability failure can be suppressed.

[0058] The foregoing description of specific exemplary embodiments of the present invention is for purposes of illustration and exemplification. These descriptions are not intended to limit the invention to the precise forms disclosed, and obviously, many changes and variations are possible in light of the above teaching. The purpose of selecting and describing the exemplary embodiments is to explain the specific principles of the present invention and its practical applications, so that those skilled in the art can implement and utilize various different exemplary embodiments of the present invention, as well as various different selections and changes. The scope of the present invention is intended to be defined by the claims and their equivalents.

Claims

1. A high-reliability directional sound screen, characterized in that: The directional sound screen comprises: A vibration layer, the vibration layer comprising a vibration base material layer and a first conductive layer, wherein the first conductive layer is entirely formed on a surface of the vibration base material layer close to the non-vibration layer; a non-vibration layer, which is in contact with the frame of the vibration layer, wherein the non-vibration layer comprises a non-vibration substrate layer, a second conductive layer and a third conductive layer, wherein the second conductive layer is entirely formed on a surface of the non-vibration substrate layer close to the vibration layer, the third conductive layer is entirely formed on a surface of the second conductive layer close to the vibration layer and is insulated and isolated from the second conductive layer by a first insulating layer, and the first conductive layer and the third conductive layer are insulated and isolated by a second insulating layer; A pattern layer, wherein the pattern layer is located between the first conductive layer and the third conductive layer, and after the vibration layer and the non-vibration layer frame are attached to each other, an air gap required for the vibration layer to vibrate up and down and generate sound is formed between the pattern layer and the non-vibration layer, and the pattern layer is a plurality of insulating units arranged at intervals; During operation, a DC voltage is first connected between the second conductive layer and the third conductive layer to extract the charge generated by air ionization, and then an AC voltage is connected between the first conductive layer and the second conductive layer or between the first conductive layer and the third conductive layer. The AC voltage ensures the generation of an electric field, thereby driving the normal vibration of the vibration layer.

2. A high-reliability directional sound screen as claimed in claim 1, characterized in that: The sheet resistance of the third conductive layer is greater than the sheet resistance of the first conductive layer.

3. A high-reliability directional sound screen as claimed in claim 1, characterized in that: The second insulating layer is a silk screen ink layer, a boron nitride coating, a nano aluminum oxide coating or a nano aluminum oxide coating.

4. A high-reliability directional sound screen as claimed in claim 3, characterized in that: The boron nitride coating, nano-aluminum oxide coating or nano-aluminum oxide coating is formed by a magnetron sputtering process.

5. A high-reliability directional sound screen as claimed in claim 1, characterized in that: Each of the insulating units includes a plurality of insulating protrusions arranged in a square shape and the sides of the square shape are parallel to the sides of the corresponding non-vibration substrate layer or the sides of the vibration substrate layer. The plurality of insulating units are arranged in an array and form a plurality of array units.

6. A high-reliability directional sound screen as claimed in claim 5, characterized in that: A supporting point is set at the center of each array unit, and the supporting point is a single point or a multi-point structure, and the height of the supporting point is less than the height of the insulating bump; or the conductive layer corresponding to the center of each array unit is removed to form a conductive layer-free portion.

7. A high-reliability directional sound screen as claimed in claim 6, characterized in that: The height of the supporting point is 2um~4um, the height of the insulating bump is 7um~12um, and the distance between two adjacent array units is 2.2um~2.8um.

8. A high-reliability directional sound screen as claimed in claim 1 or 5, characterized in that: The pattern layer is fixed to the second insulating layer or the first conductive layer via an adhesive layer, and the adhesive layer is a plurality of adhesive unit structures arranged at intervals corresponding to the structure of the pattern layer or is in a whole surface shape.

9. A high-reliability directional sound screen as claimed in claim 1, characterized in that: A waterproof layer is also arranged on the outermost surface of the vibration layer away from the non-vibration layer, and the thickness of the waterproof layer is 1 um to 10 um.

10. A process for preparing a directional sound screen, characterized in that: The directional sound-emitting screen is the directional sound-emitting screen according to any one of claims 1 to 9 above, and the preparation process comprises: S1, preparing a vibration layer, including forming a first conductive layer on the entire surface of the vibration substrate layer close to the non-vibration layer; S2, preparing a non-vibration layer, including forming a second conductive layer on the entire surface of the non-vibration substrate layer close to the vibration layer, forming the first insulating layer on the entire surface of the second conductive layer close to the vibration layer and curing it, forming the third conductive layer on the entire surface of the first insulating layer close to the vibration layer after curing, and then forming the second insulating layer on the entire surface of the third conductive layer close to the vibration layer; S3, forming a pattern layer on a surface of the first conductive layer close to the non-vibration layer or on a surface of the second insulating layer close to the vibration layer; S4, attaching the frames of the vibration layer and the non-vibration layer together, tensioning the vibration layer after attaching, and connecting a DC voltage between the first conductive layer and the second conductive layer and curing until the vibration layer and the non-vibration layer are firmly bonded.

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