TWI839829B - Acoustic device - Google Patents

Abstract

The present disclosure discloses an acoustic device, including a piezoelectric element, an electrode, and a vibration element. The piezoelectric element may generate vibration under the action of a driving voltage provided by the electrode. The vibration element may be physically connected with the piezoelectric element, receive the vibration, and generate a sound. A piezoelectric assembly includes: a substrate and a piezoelectric layer, the piezoelectric layer may be covered on one surface of the substrate, the electrode may be covered on one surface of the piezoelectric layer, and a covering area of the electrode on the surface of the piezoelectric layer may be smaller than that of the surface of the substrate covered with the piezoelectric layer. The present disclosure forms a modal actuator of the piezoelectric element by an electrode design, so that the piezoelectric element may output a specific modal shape, thereby improving a sound feature of the acoustic device. Compared with a modal control system formed by attaching different mechanical structures in a specific area, the present disclosure realizes a modal control on the piezoelectric element through an electrode design, which simplifies a structure of the acoustic device.

Description

Acoustic equipment

The present invention relates to the field of acoustic technology, and in particular to an acoustic device.

This invention claims priority to Chinese patent application No. 202210339486.6 filed on April 1, 2022, the entire contents of which are incorporated herein by reference.

Acoustic devices can transmit sound by applying electrical energy to piezoelectric elements to cause them to deform. For example, acoustic devices can apply a driving voltage in the polarization direction of the piezoelectric element, use the inverse piezoelectric effect of the piezoelectric material to generate vibrations, and output the vibrations through the vibration output point of the piezoelectric element, thereby radiating sound waves outward.

However, piezoelectric elements in acoustic devices have many vibration modes within the audible frequency range and cannot form a relatively flat frequency response curve.

Therefore, it is necessary to propose an acoustic device that can control the vibration mode of a piezoelectric element.

One of the embodiments of this specification provides an acoustic device. The device includes: a piezoelectric element, an electrode and a vibration element. The piezoelectric element generates vibration under the action of a driving voltage, the electrode provides the driving voltage for the piezoelectric element, and the vibration element can be physically connected to the piezoelectric element to receive the vibration and generate sound. The piezoelectric element may include: a substrate and a piezoelectric layer, the piezoelectric layer is covered on a surface of the substrate, the electrode is covered on a surface of the piezoelectric layer, and the covering area of the electrode on the surface of the piezoelectric layer is smaller than the area of the surface of the substrate covered with the piezoelectric layer.

In some embodiments, the piezoelectric element includes a vibration output region.

In some embodiments, the piezoelectric element further includes a fixed region.

In some embodiments, the piezoelectric element further includes a vibration regulating element.

In some embodiments, the width of the electrode gradually decreases from the fixed area to the vibration output area.

In some embodiments, the electrode includes two electrode envelope regions, and the electric potentials of the two electrode envelope regions are opposite.

In some embodiments, there is a transition point between the two electrode envelope regions, and the electrode width in the first electrode envelope region of the two electrode envelope regions gradually decreases from a fixed region to the transition point.

In some embodiments, the electrode width in the second electrode envelope region of the two electrode envelope regions first increases and then decreases from the switching point to the vibration output region.

In some embodiments, the width of the electrode in the fixed area is equal to the width of the fixed area.

In some embodiments, the width of the electrode in the vibration output region is zero.

In some embodiments, the piezoelectric layer coincides with the substrate.

In some embodiments, the piezoelectric layer includes a piezoelectric region and a non-piezoelectric region.

In some embodiments, the piezoelectric region coincides with the electrode.

In some embodiments, the piezoelectric layer coincides with the electrode.

In some embodiments, the piezoelectric layer includes a piezoelectric plate or a piezoelectric film.

In some embodiments, the electrode includes a plurality of discrete electrode units distributed in two dimensions.

In some embodiments, among the plurality of discrete electrode units, a gap between two adjacent discrete electrode units at the center of the piezoelectric layer is smaller than a gap between two adjacent discrete electrode units at the boundary of the piezoelectric layer.

In some embodiments, an area of a first discrete electrode unit at a center of the piezoelectric layer is larger than an area of a second discrete electrode unit at a boundary of the piezoelectric layer.

In some embodiments, the electrode includes a two-dimensionally distributed continuous electrode, and the continuous electrode includes a plurality of hollow regions.

In some embodiments, an area of a first hollow region at a center of the piezoelectric layer is smaller than an area of a second hollow region at a boundary of the piezoelectric layer.

In some embodiments, the electrode also covers another surface opposite to the surface, and the covering area of the electrode on the other surface is less than or equal to the area of the surface.

In some embodiments, the vibration modulation element includes a mass that is physically connected to the vibration output region.

In some embodiments, the acoustic device further includes a connector that connects the vibration element and the piezoelectric element.

In some embodiments, the acoustic device is a bone conduction audio device.

One of the embodiments of this specification provides an acoustic device. The device includes: a piezoelectric element, an electrode and a vibration element. The piezoelectric element generates vibration under the action of a driving voltage, the electrode provides the driving voltage for the piezoelectric element, and the vibration element can be physically connected to the piezoelectric element to receive the vibration and generate sound. The piezoelectric element may include: a substrate and a piezoelectric layer, the piezoelectric layer is covered on a surface of the substrate, the piezoelectric layer includes a piezoelectric region and a non-piezoelectric region, wherein the electrode is covered on a surface of the piezoelectric layer, and the substrate, the piezoelectric layer and the electrode overlap respectively. The coverage area of the piezoelectric region on the substrate is smaller than the coverage area of the piezoelectric layer on the substrate.

In some embodiments, the piezoelectric element includes a vibration output region.

In some embodiments, the piezoelectric element further includes a fixed region.

In some embodiments, the width of the piezoelectric region gradually decreases from the fixed region to the vibration output region.

In some embodiments, the piezoelectric region includes two piezoelectric envelope regions, and the electric potentials of two electrode regions corresponding to the two piezoelectric envelope regions are opposite.

In some embodiments, the width of the piezoelectric region in the fixed region is equal to the width of the fixed region.

In some embodiments, the width of the piezoelectric region in the vibration output region is zero.

In the embodiments of the present specification, a modal actuator of a piezoelectric element can be formed by electrode design, so that the piezoelectric element only generates an excitation force of a specific mode to output a specific modal vibration shape, thereby improving the sound characteristics of the acoustic device.

Furthermore, compared to adding a modal control system composed of different mechanical structures such as springs, masses, and damping in a specific area, the embodiment of the present specification can achieve modal control of piezoelectric elements based on electrode design, thereby simplifying the structure of the acoustic device.

In order to more clearly explain the technical solutions of the embodiments of this specification, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings described below are only some examples or embodiments of this specification. For those with ordinary knowledge in the relevant technical field, this specification can also be applied to other similar scenarios based on these drawings without making any progressive efforts. Unless it is obvious from the language environment or otherwise explained, the same element symbols in the drawings represent the same structure or operation.

It should be understood that the "system", "device", "unit" and/or "module" used herein are a method for distinguishing different elements, components, parts, or assemblies at different levels. However, if other words can achieve the same purpose, the words can be replaced by other expressions.

As shown in this specification and patent application, unless the context clearly indicates an exception, the words "a", "an", "an" and/or "the" do not refer to the singular, but also include the plural. Generally speaking, the terms "include" and "comprise" only indicate that the steps and elements that have been clearly identified are included, and these steps and elements do not constitute an exclusive list. The method or apparatus may also include other steps or elements.

Flowcharts are used in this specification to illustrate operations performed by the system according to the embodiments of this specification. It should be understood that the preceding or succeeding operations are not necessarily performed in exact order. Instead, the steps may be processed in reverse order or simultaneously. Also, other operations may be added to these processes, or one or more steps may be removed from these processes.

The acoustic device of one or more embodiments of the present specification can output sound through the vibration generated by the piezoelectric element, so as to be applied to various scenarios where audio needs to be played. For example, the acoustic device can be an independent audio output device (such as audio, headphones, etc.), which can play audio according to user instructions; for example, the acoustic device can be a module or component in a terminal device (such as a mobile phone, computer, etc.), which can play audio according to the terminal instructions. In some embodiments, the acoustic device can also adjust the deformation of the piezoelectric element to generate different vibrations according to the parameters such as the frequency and size of the sound to be output, so that the vibration element outputs different sounds according to different vibrations.

In some embodiments, the acoustic device may be a bone conduction acoustic device, in which the vibration element may fit the user's body tissue, and transmit the sound waves emitted by the vibration element to the user's inner ear through the user's bones. In some embodiments, the acoustic device may also be other types of acoustic devices, such as air conduction acoustic devices, hearing aids, hearing aids, glasses, helmets, augmented reality (AR) devices, virtual reality (VR) devices, etc., or alternatively, the acoustic device may be used as part of a vehicle audio system or an indoor audio system to output sound.

At present, piezoelectric components in acoustic devices have many vibration modes within the audible frequency range and cannot form a relatively flat frequency response curve. In addition, piezoelectric components may also form nodes in the vibration output area at certain frequencies, affecting the effect of acoustic output.

The embodiments of this specification describe an acoustic device. The acoustic device may include a piezoelectric element, an electrode, and a vibrating element. The piezoelectric element generates vibration under the action of a driving voltage, the electrode provides the driving voltage for the piezoelectric element, and the vibrating element can be physically connected to the piezoelectric element, receives the vibration and generates sound. The piezoelectric element may include: a substrate and a piezoelectric layer. In some embodiments, the piezoelectric layer is covered on a surface of the substrate, the electrode is covered on a surface of the piezoelectric layer, and the covering area of the electrode on the surface of the piezoelectric layer is smaller than the area of the surface of the substrate covered with the piezoelectric layer. In some embodiments, the piezoelectric layer is covered on one surface of the substrate, the electrode is covered on one surface of the piezoelectric layer, and the substrate, the piezoelectric layer and the electrode overlap respectively. The piezoelectric layer includes a piezoelectric region and a non-piezoelectric region, and the coverage area of the piezoelectric region on the substrate is smaller than the coverage area of the piezoelectric layer on the substrate.

In the embodiments of the present specification, a modal actuator of a piezoelectric element can be formed by electrode design, so that the piezoelectric element only generates an excitation force of a specific mode to output a specific modal vibration shape, thereby improving the sound characteristics of the acoustic device.

Furthermore, compared to a modal control system that is composed of mechanical structures such as springs, masses, and damping added to a specific area, the embodiment of this specification can achieve modal control of piezoelectric elements based on electrode design, thereby simplifying the structure of the acoustic device.

FIG1 is a structural block diagram of an exemplary acoustic device 100 according to some embodiments of the present specification. In some embodiments, as shown in FIG1 , the acoustic device 100 may include: a vibration element 110, a piezoelectric element 120, and an electrode 130. The piezoelectric element 120 generates vibration under the action of a driving voltage, the electrode 130 provides the driving voltage for the piezoelectric element 120, and the vibration element 110 may be physically (e.g., mechanically or electromagnetically) connected to the piezoelectric element 120, receives vibration and generates sound.

The vibration element 110 can be configured as an element that transmits vibration and generates sound. In some embodiments, the vibration element 110 may include an elastic element, which can respond to vibration and deform, change the sound pressure around itself, thereby generating sound waves and realizing the output of sound. In some embodiments, the elastic element may include a vibration-transmitting sheet, glue, a spring sheet, etc., or any combination thereof. In some embodiments, the material of the elastic element may be any material that has the ability to transmit vibration. For example, the material of the elastic element may be silicone, plastic, rubber, metal, etc., or any combination thereof. In some embodiments, the vibration element 110 may be a membrane structure (such as an air-conducted vibration membrane, etc.), or a plate structure (such as a bone-conducted vibration panel, etc.), or other structures such as a mesh structure or a layered structure.

An exemplary acoustic device 100 is provided below to describe a specific implementation of the vibration element 110 .

FIG. 2 is a schematic diagram of the structure of an exemplary acoustic device 100 according to some embodiments of the present specification. As shown in FIG. 2 , one end of the vibration element 110 can be connected to the vibration output region 123 of the piezoelectric element 120 to receive vibration. The other end of the vibration element 110 can output sound. Exemplarily, the vibration element 110 can send sound waves to the user through one or more media (such as air, user's bones, etc.), so that the user hears the sound output by the acoustic device 100.

The piezoelectric element 120 may be configured as an electric energy conversion device that converts electric energy into mechanical energy. In some embodiments, the piezoelectric element 120 may be deformed under the action of a driving voltage, thereby generating vibration. In some embodiments, the piezoelectric element 120 may be in the shape of a sheet, a ring, a diamond, a rectangular parallelepiped, a column, a sphere, or any combination thereof, or may be other irregular shapes. In some embodiments, the piezoelectric element 120 may include a substrate 121 and a piezoelectric layer 122.

The substrate 121 can be configured as a carrier for carrying components and an element that deforms in response to vibration. In some embodiments, the material of the substrate 121 can include: a combination of one or more of metal (such as copper foil, steel, etc.), phenolic resin, cross-linked polystyrene, etc. In some embodiments, the shape of the substrate 121 can be determined according to the shape of the piezoelectric element 120. For example, if the piezoelectric element 120 is a piezoelectric beam, the substrate 121 can be correspondingly configured as a long strip. For another example, if the piezoelectric element 120 is a piezoelectric film, the substrate 121 can be correspondingly configured as a plate or sheet.

The piezoelectric layer 122 may be an element configured to provide a piezoelectric effect and/or an inverse piezoelectric effect. In some embodiments, the piezoelectric layer 122 may cover one or more surfaces of the substrate 121, and deform under the action of a driving voltage to drive the substrate 121 to deform, thereby achieving the output vibration of the piezoelectric element 120. In some embodiments, the piezoelectric layer 122 may be entirely a piezoelectric region, that is, the piezoelectric layer 122 may be made of a piezoelectric material. In some embodiments, the piezoelectric layer 122 may include a piezoelectric region and a non-piezoelectric region. The piezoelectric region and the non-piezoelectric region are connected to form the piezoelectric layer 122. In some embodiments, the piezoelectric region is made of a piezoelectric material, and the non-piezoelectric region is made of a non-piezoelectric material. In some embodiments, the piezoelectric material may include a piezoelectric crystal, a piezoelectric ceramic, a piezoelectric polymer, or the like, or any combination thereof. In some embodiments, the piezoelectric crystal may include crystal, sphalerite, borate, pyroxene, ruthenium, GaAs, barium titanate and its derivative structure crystals, KH ₂ PO ₄ , NaKC ₄ H ₄ O ₆ ·4H ₂ O (sodium potassium tartrate), or the like, or any combination thereof. In some embodiments, the piezoelectric ceramic refers to a piezoelectric polycrystal formed by an irregular aggregation of fine grains obtained by solid-phase reaction and sintering between powder particles of different materials. In some embodiments, the piezoelectric ceramic material may include barium titanium (BT), lead zirconium titanium (PZT), barium lithium lead niobium (PBLN), modified lead titanium (PT), aluminum nitride (AIN), zinc oxide (ZnO), etc., or any combination thereof. In some embodiments, the piezoelectric polymer material may include polyvinylidene fluoride (PVDF), etc. In some embodiments, the non-piezoelectric material may include ceramics, rubber. In some embodiments, the mechanical properties of the non-piezoelectric material may be similar to the mechanical properties of the piezoelectric material. In some embodiments, the specific implementation of the piezoelectric region and the non-piezoelectric region can refer to the relevant content shown in Figure 8A or Figure 8D below, which will not be repeated here.

The electrode 130 may be configured as an element that provides a driving voltage for the piezoelectric element 120. In some embodiments, the electrode 130 may be a combination of one or more of a metal electrode (such as a copper electrode, a silver electrode, etc.), a redox electrode (such as a Pt|Fe and Fe electrode, a Pt|Mn MnO electrode), a sparingly soluble salt electrode (such as a calomel electrode, a mercuric oxide electrode), etc. In some embodiments, the electrode 130 may be disposed on at least one surface of the piezoelectric layer 122, for example, it may be disposed on two opposite surfaces of the piezoelectric layer 122. In some embodiments, the electrode may be disposed on the surface of the piezoelectric layer 122 by one or more bonding methods such as coating, inlaying, and fitting.

In some embodiments, the piezoelectric layer 122 may cover at least one surface of the substrate 121. In some embodiments, the electrode 130 may cover at least one surface of the piezoelectric layer 122. FIGS. 3 and 4 provide two exemplary piezoelectric elements 120 to describe the arrangement of the substrate 121, the piezoelectric layer 122, and the electrode 130.

FIG3 is a schematic diagram of the structure of an exemplary piezoelectric element 120 according to some embodiments of the present specification. As shown in FIG3, the piezoelectric element 120 can be a piezoelectric cantilever beam. The substrate 121 can carry the piezoelectric layer 122 and the electrode 130 (shown in the triangular region). In some embodiments, the electrode 130 can be disposed on one or more surfaces of the piezoelectric layer 122 to provide a driving voltage for the piezoelectric layer 122. In some embodiments, the piezoelectric layer 122 can be covered on one or more surfaces of the substrate 121, and when the piezoelectric layer 122 is deformed under the action of the driving voltage, the substrate 121 can also be deformed accordingly, so that the vibration output region of the piezoelectric element 120 outputs vibration. For example, the piezoelectric layer 122 may only cover one surface of the substrate 121. For another example, as shown in FIG3, two piezoelectric layers 122 may respectively cover two opposite surfaces of the substrate 121.

FIG4 is a partial structural schematic diagram of an exemplary piezoelectric element 120 according to some embodiments of the present specification. As shown in FIG4 , the piezoelectric element 120 may be a piezoelectric plate (or a piezoelectric film). The substrate 121 may carry a piezoelectric layer 122 and an electrode 130 (shown as a plurality of two-dimensionally distributed squares). In some embodiments, the area of the piezoelectric layer 122 may be larger than or smaller than the substrate 121. In some embodiments, the electrode 130 may be disposed on one or more surfaces of the piezoelectric plate to provide a driving voltage for the piezoelectric plate. In some embodiments, the piezoelectric layer 122 may be covered on one or more surfaces of the substrate 121. When the piezoelectric layer 122 is deformed under the action of the driving voltage, the substrate 121 may also be deformed accordingly, so that the vibration output area of the piezoelectric plate outputs vibration. For example, as shown in FIG4 , the piezoelectric layer 122 may only be covered on one surface of the substrate 121. For another example, two piezoelectric layers 122 may be respectively covered on two opposite surfaces of the substrate 121.

In some embodiments, the piezoelectric element 120 may include a vibration output region 123 for transmitting the vibration generated by the piezoelectric element 120 to the vibration element 110. In some embodiments, the vibration output region 123 may be a surface, an edge, or a point of the piezoelectric element 120, or any combination thereof. As shown in FIG3 , when the piezoelectric component 120 is a piezoelectric cantilever beam, a diamond or a partial area of the surface of the piezoelectric element 120 may be the vibration output region 123. As shown in FIG4 , when the piezoelectric component 120 is a piezoelectric plate or a piezoelectric film, the internal area of the piezoelectric element 120 (e.g., the central area of the vibration plane) may be the vibration output region 123.

In some embodiments, the piezoelectric element 120 may further include a fixed region 124. The fixed region 124 is used to fix a portion of the piezoelectric element 120 and suppress the piezoelectric element 120 from vibrating in the region, so that most of the vibration of the piezoelectric element 120 can be output from the vibration output region 123. In some embodiments, the fixed region 124 may be opposite to the vibration output region 123. As shown in FIG3 , when the piezoelectric component 120 is a piezoelectric cantilever beam, one end of the piezoelectric element 120 along the long axis direction may be the vibration output region 123, and the other end of the long axis direction opposite to the vibration output region 123 may be the fixed region 124. For another example, when the piezoelectric element 120 is a piezoelectric plate or a piezoelectric film, the vibration output region 123 may be an inner region of the piezoelectric element 120 , and the boundary region of the piezoelectric element 120 may be the fixed region 124 .

In some embodiments, the piezoelectric element 120 may not be provided with the fixed area 124, and the vibration can be transmitted through the vibration output area 123 to reduce the process flow and cost, and at the same time, the piezoelectric element 120 can be easily moved.

In some embodiments, the vibration of the piezoelectric element 120 may include one or more vibration modes. The vibration mode is the inherent vibration characteristic of the structural system. If the electrode shape is not designed, the piezoelectric element 120 has many vibration modes, which makes the frequency response curve unstable, and may seriously cause the formation of nodes in the vibration output area of the piezoelectric element 120 at certain frequencies, affecting the effect of the acoustic output.

In some embodiments, the shape of the electrode 130 can be designed so that the electrode 130 forms a piezoelectric modal actuator to output an excitation force, so that the piezoelectric element 120 only generates a specific mode. In some embodiments, the covering area of the electrode 130 on the surface of the piezoelectric layer 122 can be smaller than the area of the surface of the substrate 121 covered with the piezoelectric layer 122, thereby realizing the electrode design. For example, as shown in FIG3 , the area of the electrode 130 (shown as a quasi-triangular region) may be smaller than the area of the piezoelectric layer 122 and smaller than the area of the substrate 121, wherein the piezoelectric layer 122 may overlap with the substrate 121 (i.e., the coverage area of the piezoelectric layer 122 on the substrate 121 is the entire surface area of one surface of the substrate 121). For another example, as shown in FIG4 , the area of the electrode 130 (shown as a plurality of two-dimensionally distributed squares) may be smaller than the area of the piezoelectric layer 122 and smaller than the area of the substrate 121, wherein the piezoelectric layer 122 may overlap with the substrate 121 (i.e., the coverage area of the piezoelectric layer 122 on the substrate 121 is the entire surface area of one surface of the substrate 121).

In some embodiments, the contour curve of the electrode 130 can be determined according to the vibration mode function of the vibration structure of the piezoelectric element 120, so as to perform modal control on the piezoelectric element 120. In some embodiments, the vibration mode function of the piezoelectric element 120 can include a first-order vibration mode and a second-order vibration mode, etc. Correspondingly, the electrode 130 can include a first-order electrode 130-1 corresponding to the first-order vibration mode, and a second-order electrode 130-2 corresponding to the second-order vibration mode, etc.

Taking the piezoelectric cantilever beam shown in FIG. 3 as an example, two exemplary first-order electrodes 130 - 1 and second-order electrodes 130 - 2 are provided to describe in detail the specific implementation of the electrode design.

Fig. 5A is a schematic diagram of the structure of an exemplary first-order electrode 130-1 according to some embodiments of the present specification. Fig. 5B is a schematic diagram of the curve slope of the outer contour of an exemplary portion of the first-order electrode 130-1 according to some embodiments of the present specification.

In some embodiments, the width of the electrode 130 may gradually decrease from the fixed area 124 to the vibration output area 123. The "width of the electrode 130" mentioned here refers to the size of the electrode in the width direction of the piezoelectric component 120 (such as the width direction of the piezoelectric cantilever beam). Among them, the width of the electrode 130 at a certain position (such as d1, d2 shown in Figure 5A) can be the distance between the two intersections of the line perpendicular to the central axis of the piezoelectric element 120 along the length direction and the outer contour line of the electrode 130 at this position. In some embodiments, the width of the electrode 130 gradually decreases from the fixed area 124 to the vibration output area 123, which may include a gradient reduction, a linear reduction, or a curvilinear reduction, or any combination thereof. As shown in FIG5A , the width of the first-order electrode 130-1 may decrease curvilinearly from the left side (i.e., the fixed area 124) to the right side (i.e., the vibration output area 123). As shown in FIG5B , the absolute value of the curve slope of the outer contour of the first-order electrode 130-1 above the mid-axis line gradually decreases from the vibration fixed area 124 as the length increases, and decreases to 0 at the vibration output area 123. In some embodiments, the electrode 130 may be symmetrically arranged, such as the electrode 130 may be symmetrical along the central axis of the piezoelectric element 120. In some embodiments, the electrode 130 may also be asymmetrically arranged. In some embodiments, the shape curve (i.e., the outer contour) of the electrode 130 may be a trigonometric function (e.g., a sine function, a cosine function, etc.), a hyperbolic function (e.g., a hyperbolic sine function, a hyperbolic cosine function, etc.), or any combination (e.g., a linear combination).

Fig. 5C is a schematic diagram of the structure of an exemplary secondary electrode 130-2 according to some embodiments of the present specification. Fig. 5D is a schematic diagram of the curve slope of the outer contour of an exemplary portion of the secondary electrode 130-2 according to some embodiments of the present specification.

In some embodiments, the electrode 130 may include two electrode envelope regions, and the potentials of the two electrode envelope regions are opposite. The electrode envelope region may be a region where the conductive medium of the electrode 130 is located, and the potential of the electrode envelope region may be a voltage at both ends of the electrode envelope region. For example, as shown in FIG5C , the voltage at both ends of the first electrode envelope region 131 of the secondary electrode 130-2 may be positive, and the voltage at both ends of the second electrode envelope region 132 may be negative. Optionally, the voltage at both ends of the first electrode envelope region 131 may be negative, and the voltage at both ends of the second electrode envelope region 132 may be positive.

In some optional embodiments, when the polarization directions of the two electrode envelope regions are the same, the two electrode envelope regions can be controlled to be connected to electric potentials in opposite directions, so that the electric potentials of the two electrode envelope regions are opposite. In some optional embodiments, when the polarization directions of the two electrode envelope regions are opposite, the two electrode envelope regions can be controlled to be connected to electric potentials in the same direction, so that the electric potentials of the two electrode envelope regions are opposite.

In some embodiments, a transition point 133 may exist between the two electrode envelope regions, and the electrode width in the first electrode envelope region 131 of the two electrode envelope regions may gradually decrease from the fixed region 124 to the transition point 133.

In some embodiments, the transition point 133 may be a point between the electrode envelope regions where the potential is 0, and the potential directions of the regions on both sides of the point (i.e., the two electrode envelope regions) are opposite. In some embodiments, the transition point 133 may be used to distinguish the electrode envelope regions. For example, the electrode envelope region between the fixed region 124 and the transition point 133 may be the first electrode envelope region 131. Among them, the width of the electrode in the first electrode envelope region 131 at a certain position (such as d3 shown in FIG. 5C ) may be the distance between the two intersection points of a line perpendicular to the central axis of the piezoelectric element 120 along the length direction and the outer contour line of the electrode 130 at the position. In some embodiments, the reduction in electrode width in the first electrode envelope region 131 may include one or any combination of gradient reduction, linear reduction or curved reduction.

For example, as shown in FIG5C , when the electrode 130 is a second-order electrode 130-2, the potential at the transition point 131 may be 0, and the potentials of the first electrode envelope region 131 and the second electrode envelope region 132 are opposite. In addition, the width of the first electrode envelope region 131 may decrease in a curve from the left side (i.e., the fixed region 124) to the transition point 133. As shown in FIG5D , in the first electrode envelope region 131, the absolute value of the curve slope of the outer contour of the second-order electrode 130-2 above the mid-axis gradually decreases as the length increases from the vibration fixed region 124 to the transition point 133.

In some embodiments, the electrode width in the second electrode envelope region 132 of the two electrode envelope regions first increases and then decreases from the transition point 133 to the vibration output region 123. The width of the electrode in the second electrode envelope region 132 at a certain position (such as d4 shown in FIG. 5C ) may be the distance between the two intersection points of a line perpendicular to the central axis of the piezoelectric element 120 along the length direction and the outer contour line of the electrode 130 at the position. In some embodiments, the electrode envelope region between the transition point 133 and the vibration output region 123 may be the second electrode envelope region 132. In some embodiments, the electrode width in the second electrode envelope region 132 increases first and then decreases, and may include one or more reduction methods such as gradient change, linear change, or curvilinear change. For example, as shown in FIG5C , the electrode width in the second electrode envelope region 132 may increase curvilinearly from the left side (i.e., the transition point 133), and the increase amplitude becomes smaller and smaller until the width reaches a peak value and then begins to decrease curvilinearly, and ends at the vibration output region 123, and the decrease amplitude first increases and then decreases. As shown in FIG5D , within the second electrode envelope region 132, the absolute value of the curve slope of the outer contour of the second-order electrode 130-2 above the mid-axis first decreases with increasing length from the transfer point 133, and the curve slope decreases to 0 at the widest point of the second electrode envelope region 132. Thereafter, as the length increases, the absolute value of the curve slope first increases and then decreases, and decreases to 0 in the vibration output region 123.

In some embodiments, the electrode 130 may further include one or more envelope regions such as a third electrode envelope region and a fourth electrode envelope region. The shape and number of the electrode envelope regions may be determined according to the vibration mode of the piezoelectric element 120 to be controlled.

In some embodiments, the width of the electrode 130 in the fixed area 124 may be equal to the width of the fixed area 124. As shown in FIG5A and FIG5C, the width of the fixed area 124 may be D, and correspondingly, the width of the electrode 130 in the fixed area 124 may also be D.

In some optional embodiments, the width of the electrode 130 in the fixed area 124 may not be equal to the width of the fixed area 124 , for example, the width of the electrode 130 may be smaller than the width of the fixed area 124 , or may be larger than the width of the fixed area 124 .

In some embodiments, the width of the electrode 130 in the vibration output area 123 may be 0. As shown in FIG5A and FIG5C , the width of the electrode 130 in the vibration output area 123 may be 0.

In some optional embodiments, the width of the electrode 130 in the vibration output area 123 may not be 0. For example, the width of the electrode 130 in the vibration output area 123 may be smaller than the width of the electrode 130 in the fixed area 124 and greater than 0.

FIG6 is a comparative schematic diagram of the frequency response curves of exemplary piezoelectric elements shown in some embodiments of this specification. As shown in FIG6, curve 1 is a frequency response curve of the piezoelectric element 120 at the vibration output region when the electrode 130 completely covers one surface of the piezoelectric element 120 (i.e., the electrode 130 overlaps with the piezoelectric element 120). Curve 2 is a frequency response curve of the piezoelectric element 120 using the first-order electrode shape as shown in FIG5A, and curve 3 is a frequency response curve of the piezoelectric element 120 using the second-order electrode shape as shown in FIG5C (and the potentials of the two envelopes are opposite).

As shown in FIG6 , curve 1 has a first-order peak and a second-order valley, which reflects that when the electrode 130 completely covers a surface of the piezoelectric element 120 (i.e., the electrode 130 overlaps with the piezoelectric element 120), the piezoelectric element 120 has a relatively complex vibration mode in the medium and high frequency range, especially a significantly different vibration response in the range of 500Hz to 3000Hz. After adopting the first-order electrode shape, the first-order modal frequency band of the piezoelectric component 120 shown in curve 2 is extended, the second-order valley disappears, and a narrowband jump of the curve is generated at the second-order peak frequency (such as near 3000Hz), and the amplitude of the second-order peak is also reduced. In this way, the arrangement of the first-order electrode 130-1 can make the vibration response of the piezoelectric element 120 between the first-order peak and the second-order peak flatter. After the second-order electrode 130-2 is adopted (and the potentials of the two envelope regions are opposite), the frequency response curve of the piezoelectric element 120 shown in curve 3 is in the second-order vibration mode from the low-frequency stage (such as 0-100Hz), and a narrow-band jump of the curve is generated at the first-order peak frequency (such as between 500Hz-600Hz), reducing the amplitude of the first-order peak. After the peak frequency, it is in the second-order vibration mode until the third-order peak frequency (such as 9000hz). In this way, the arrangement of the second-order electrode 130-2 can make the piezoelectric element 120 in the second-order array from the low-frequency stage to the third-order peak. It can be seen from curves 2 and 3 that the first-order electrode morphology and the second-order electrode morphology (and the potentials of the two envelopes are opposite) have a modal control effect. The "peak frequency" in this specification refers to the peak (for example, first-order peak, second-order peak, third-order peak, etc.) frequency of the piezoelectric element 120 when the electrode 130 completely covers a surface of the piezoelectric element 120 (that is, the electrode 130 overlaps with the piezoelectric element 120).

In addition, as shown in FIG6 , curve 4 is a frequency response curve of the piezoelectric element 120 using the second-order electrode 130-1 as shown in FIG5C (and the potentials of the two envelopes are the same); curve 5 is a frequency response curve of the piezoelectric element 120 using a triangular electrode (i.e., an isosceles triangle formed by the center points of the fixed area 124 and the vibration output area 123 of the piezoelectric element 120 is used as the shape of the electrode). Among them, when the triangular electrode is used, the frequency response curve of the piezoelectric element 120 shown in curve 5 still has a second-order valley, but the second-order valley is significantly shifted backward compared to curve 1 which is completely covered by the electrode. In this way, the arrangement of the triangular electrode 130 can make the response of the piezoelectric element 120 between the first-order peak frequency and the second-order valley frequency flatter. After adopting the second-order electrode 130-2 (and the potentials of the two envelopes are opposite), the frequency response curve of the piezoelectric element 120 shown in curve 4 is similar to curve 1 (the electrode 130 completely covers one surface of the piezoelectric element 120).

7A is a vibration mode diagram of the piezoelectric component 120 at the second-order valley frequency when the electrode completely covers a surface of the piezoelectric element (i.e., the electrode overlaps the piezoelectric element); FIG7B is a vibration mode diagram of the piezoelectric element 120 using a first-order electrode 130-1 at the second-order valley frequency according to some embodiments of the present specification; FIG7C is a vibration mode diagram of the piezoelectric element 120 using a second-order electrode 130-2 at the second-order valley frequency according to some embodiments of the present specification.

In conjunction with FIG. 6 and FIG. 7A to FIG. 7C , at the second-order valley frequency (e.g., 1622 Hz), when the electrode completely covers one surface of the piezoelectric element (i.e., the electrode overlaps the piezoelectric element), the vibration response of the piezoelectric element 120 fluctuates greatly and the frequency response curve is not flat. However, the vibration response of the piezoelectric component 120 with electrode design (e.g., the first-order electrode 130-1 or the second-order electrode 130-2) fluctuates less, the frequency response curve is flatter, and it is less likely to form nodes.

In the embodiment of the present specification, the modal actuator of the piezoelectric element 120 can be formed by designing the electrode 130, so that the piezoelectric element 120 only generates a specific modal excitation force to output a specific modal vibration shape, thereby improving the sound characteristics of the acoustic device. In addition, the frequency response curve of the piezoelectric element 120 can be more stable, thereby avoiding the formation of nodes in the vibration output area 123 of the piezoelectric element 120, and improving the working reliability of the acoustic device 100.

Furthermore, compared to a modal control system that is composed of mechanical structures such as springs, masses, and damping added to a specific area, the embodiment of the present specification can achieve modal control of the piezoelectric element 120 based on the design of the electrode 130, thereby simplifying the structure of the acoustic device 100.

In some embodiments, the piezoelectric element 120 may also be designed according to the design of the electrode 130. The following uses a number of exemplary designs using a one-dimensional, one-order electrode 130-1 as an example to describe in detail the specific implementation of designing the piezoelectric element 120.

FIG8A is a schematic diagram of the structure of the electrode 130 and the piezoelectric element 120 according to some embodiments of the present specification; FIG8B is a schematic diagram of the structure of the electrode 130 and the piezoelectric element 120 according to some embodiments of the present specification; FIG8C is a schematic diagram of the structure of the electrode 130 and the piezoelectric element 120 according to some embodiments of the present specification; FIG8D is a schematic diagram of the exploded structure of the electrode 130 and the piezoelectric element 120 according to some embodiments of the present specification. It should be understood that the triangular area (or quasi-triangular area) in FIG8A-8D is only for illustration and is not used to limit the shape of the electrode.

In some embodiments, as shown in FIG. 3 , the substrate 121 may be a rectangle, the piezoelectric layer 122 may be a piezoelectric rectangular beam overlapping the substrate 121 (the piezoelectric layer 122 is entirely a piezoelectric region), and the electrode 130 may be a first-order electrode 130-1, that is, the coverage area of the electrode 130 (shown as a triangular region) < the coverage area of the piezoelectric layer 122 = the surface area of the substrate 121 covering the piezoelectric layer 122.

In some embodiments, as shown in FIG. 8A , the substrate 121 may be rectangular, the piezoelectric layer 122 may be a piezoelectric rectangular beam overlapping the substrate 121 , and the electrode 130 may be a first-order electrode 130 - 1 . The piezoelectric layer 122 includes a piezoelectric region 1221 (made of piezoelectric material) and a non-piezoelectric region 1222 (made of non-piezoelectric material), wherein the piezoelectric region 1221 coincides with the first-order electrode 130-1 (the dotted line inside the piezoelectric region 1221 is only used to distinguish the piezoelectric region 1221 from the electrode 130, and is not used to limit the size of the two), that is, the coverage area of the electrode 130 (shown as a triangular region) = the coverage area of the piezoelectric region 1221 < the coverage area of the piezoelectric layer 122 = the surface area of the substrate 121 covering the piezoelectric layer 122.

In some embodiments, as shown in FIG. 8B , the substrate 121 may be rectangular, the electrode 130 may be a first-order electrode 130-1, the piezoelectric layer 122 may overlap with the electrode 130, and the covering area is smaller than the surface area of the substrate 121 covering the piezoelectric layer 122, that is, the covering area of the electrode 130 (shown as a triangular region) = the covering area of the piezoelectric layer 122 < the surface area of the substrate 121 covering the piezoelectric layer 122. In other words, the piezoelectric material in the electrode-uncovered region of the piezoelectric layer 122 is removed, and the substrate is retained as a rectangular beam.

In some embodiments, as shown in FIG. 8C , the electrode 130 may be a first-order electrode 130 - 1, and the substrate 121 and the piezoelectric layer 122 may both overlap with the electrode 130 , that is, the coverage area of the electrode 130 (shown as a triangular-shaped area) = the coverage area of the piezoelectric layer 122 = the surface area of the substrate 121 covering the piezoelectric layer 122 .

In some embodiments, the piezoelectric layer 122 may overlap with the substrate 121. For example, as shown in FIG. 3 or FIG. 8C , the coverage area of the piezoelectric layer 122 = the surface area of the substrate 121 covering the piezoelectric layer 122. In some optional embodiments, the piezoelectric layer 122 may not overlap with the substrate 121. For example, as shown in FIG. 8B , the area of the piezoelectric layer 122 may be smaller than the area of the substrate 121.

In some embodiments, the piezoelectric layer 122 may be entirely a piezoelectric region. For example, as shown in FIG. 3 , FIG. 8B , or FIG. 8C , the piezoelectric layer 122 may be entirely supported by a piezoelectric material. In some embodiments, the piezoelectric layer 122 may include a piezoelectric region 1221 and a non-piezoelectric region 1222 . For example, as shown in FIG. 8A , the piezoelectric layer 122 includes a piezoelectric region 1221 made of a piezoelectric material and a non-piezoelectric region 1222 made of a non-piezoelectric material, and the area of the piezoelectric layer 122 is equal to the sum of the area of the piezoelectric region 1221 and the area of the non-piezoelectric region 1222.

In some embodiments, the piezoelectric region 1221 may overlap with the electrode 130. For example, as shown in FIG8A , the piezoelectric region 1221 in the piezoelectric layer 122 and the electrode 130 have the same coverage area and their spatial positions overlap with each other.

In some embodiments, the piezoelectric layer 122 may overlap with the electrode 130. For example, as shown in FIG8B or FIG8C , the coverage area of the piezoelectric layer 122 is equal to the coverage area of the electrode 130, and the spatial positions overlap with each other.

In some embodiments, the effective electrode portion of the electrode 130 can generate a specific mode for the piezoelectric element 120 by designing the covering shape of the electrode 130 and the piezoelectric region. For example, the piezoelectric layer 122 may include a piezoelectric region made of a piezoelectric material and a non-piezoelectric region made of a non-piezoelectric material. The sum of the areas of the piezoelectric region and the non-piezoelectric region is equal to the covering area of the piezoelectric layer 122 on the substrate 121, and the substrate 121 and the piezoelectric layer 122 overlap. The sum of the areas of the piezoelectric region and the non-piezoelectric region is equal to the covering area of the electrode 130 on the piezoelectric layer 122, that is, the electrode 130 and the piezoelectric layer 122 overlap. In some embodiments, the coverage area of the piezoelectric region on the substrate 121 may be smaller than the coverage area of the piezoelectric layer 122 on the substrate 121. For example, as shown in FIG8D , the substrate 121 may be rectangular, the piezoelectric layer 122 may be a piezoelectric rectangular beam overlapping the substrate 121, and the electrode 130 may be a rectangular electrode. The piezoelectric layer 122 includes a piezoelectric region 1221 and a non-piezoelectric region 1222, wherein the shape and area of the piezoelectric region 1221 (shown as a diagonal filled area) are used to define the effective area of the rectangular electrode 130, that is, the area of the piezoelectric region 1221 < the covering area of the piezoelectric layer 122 = the covering area of the electrode 130 = the surface area of the substrate 121 covering the piezoelectric layer 122. Among them, the portion of the electrode 130 covering the piezoelectric region 1221 can provide a driving voltage for the piezoelectric element 120, that is, the portion of the electrode 130 can be an effective electrode portion, and the portion of the electrode 130 covering the non-piezoelectric region 1222 is only used as a conductive element to transmit electrical energy to the effective electrode portion, so that the covering area of the piezoelectric region 1221 on the substrate 121 can be regarded as the area of the effective area of the electrode 130. In this way, the design of the electrode 130 can be realized by designing the piezoelectric region 1221, so that the portion of the electrode 130 covering the piezoelectric region 122 can control the piezoelectric element 120 to output a specific mode.

Fig. 9 is a schematic diagram of a frequency response curve of a piezoelectric element 120 according to some embodiments of the present specification. In some embodiments, curve 6 is a frequency response curve of the piezoelectric element 120 when the rectangular electrode completely covers one surface of the rectangular piezoelectric element (i.e., the electrode, the piezoelectric element and the substrate all overlap). Curve 7 is the frequency response curve of the piezoelectric component 120 shown in FIG. 3 (i.e., the coverage area of the electrode 130 < the coverage area of the piezoelectric layer 122 = the surface area of the substrate 121 covering the piezoelectric layer 122), and Curve 8 is the frequency response curve of the piezoelectric component 120 shown in FIG. 8A or FIG. 8D (i.e., the coverage area of the electrode 130 = the coverage area of the piezoelectric region 1221 < the coverage area of the piezoelectric layer 122 = the surface area of the substrate 121 covering the piezoelectric layer 122, or the coverage area of the piezoelectric region 1221 < the coverage area of the piezoelectric layer 122 = the coverage area of the electrode 130 = the surface area of the substrate 121 covering the piezoelectric layer 122), curve 9 is the frequency response curve of the piezoelectric component 120 shown in FIG. 8B (i.e., the coverage area of the electrode 130 = the coverage area of the piezoelectric layer 122 < the surface area of the substrate 121 covering the piezoelectric layer 122), and curve 10 is the frequency response curve of the piezoelectric component 120 shown in FIG. 8C (i.e., the coverage area of the electrode 130 = the coverage area of the piezoelectric layer 122 = the surface area of the substrate 121 covering the piezoelectric layer 122).

As shown in FIG9 , when the electrode completely covers one surface of the piezoelectric element (i.e., the electrode and the piezoelectric element overlap), the frequency response curve of the piezoelectric element 120 shown in curve 6 has a first-order peak and a second-order valley, and the piezoelectric element 120 has multiple modes. The frequency response characteristics of curves 7 and 8 are similar, which can reflect that the characteristics of the frequency response curves are similar when the piezoelectric material in the uncovered area of the electrode is replaced with a non-piezoelectric material (or the shape of the piezoelectric area is used to define the effective area of the electrode) compared with the piezoelectric material being used entirely. The frequency response amplitude of curve 9 is significantly increased, while the low-frequency peak moves toward high frequency, the second-order mode is significantly suppressed, and smoothly transitions to the third-order valley. This phenomenon can reflect that when the piezoelectric material in the uncovered area of the electrode 130 is removed, the piezoelectric layer 122 overlaps with the electrode 130, and the covering area of the piezoelectric layer 122 (or the electrode 130) is smaller than the surface area of the substrate 121 covering the piezoelectric layer 122, a modal control effect can be caused. The frequency response curve shown in curve 10 still has first-order peaks and second-order valleys, and still has multiple modes. This phenomenon can reflect that when the substrate 121, the piezoelectric layer 122 and the electrode 130 are all in the shape of the first-order electrode 130-1, their frequency response characteristics are consistent with when the electrode completely covers one surface of the piezoelectric element (that is, the electrode and the piezoelectric element overlap). Therefore, the shape of the first-order electrode 130-1 may affect the vibration mode of the rectangular piezoelectric cantilever beam, but cannot control the vibration mode of the piezoelectric cantilever beam of the same shape (such as the shape of the first-order electrode 130-1).

In some embodiments, the potential distribution of the piezoelectric layer 122 when the first-order electrode 130-1 is used to cover the piezoelectric region 1221 has the same regularity as the potential distribution of the piezoelectric layer 122 when the first-order electrode 130-1 is used to cover the piezoelectric region 1221 and the other regions of the piezoelectric layer 122 are replaced with the non-piezoelectric region 1222 made of non-piezoelectric material. For example, when the vibration frequency of the piezoelectric element 120 is about 100 Hz, there is no potential difference in the area of the piezoelectric layer 122 not covered by the first-order electrode 130-1 in the piezoelectric component 120 as shown in FIG3 , and after the material of the uncovered area of the electrode 130 on the piezoelectric layer 122 is replaced with a non-piezoelectric material as shown in FIG8A , the uncovered non-piezoelectric area of the electrode has no electrical properties.

In the embodiments of the present specification, the piezoelectric element 120 can be designed according to the design of the electrode 130, and the area of the piezoelectric element 120 not covered by the electrode can be replaced by a non-piezoelectric material from a piezoelectric material, thereby ensuring that the piezoelectric element 120 can output vibration normally while reducing the manufacturing cost of the piezoelectric element 120.

FIG. 10 is a schematic structural diagram of a piezoelectric element 120 of an exemplary additional mass block model 140 according to some embodiments of the present specification.

In some embodiments, the vibration output region of the piezoelectric element 120 can be connected to the vibration element 110 and/or other elements. In some embodiments, the vibration element 110 and/or other elements can be simplified to a mass block model 140 so as to design the contour curve of the electrode 130. Exemplarily, as shown in Figure 10, the vibration output region 123 of the piezoelectric element 120 is connected to the mass block model 140. Among them, the mass block model 140 can transmit vibration and output vibration through its own second vibration output region 141. In some embodiments, the second vibration output region 141 can include a face, an edge or a point of the mass block model 140, or any combination thereof. As shown in Figure 10, the second vibration output region 141 can include the center point of the mass block model 140. The specific implementation of the second vibration output area 141 can refer to the relevant description in the above-mentioned Figures 3-4, and will not be repeated here.

In some embodiments, the contour curve of the electrode 130 can be determined according to the mass relationship between the piezoelectric element 120 and the mass block model 140 and the vibration structure of the piezoelectric element 120, and the piezoelectric element 120 can be modally controlled. In some embodiments, the mass relationship between the piezoelectric element 120 and the mass block model 140 can include the ratio of the mass of the mass block model 140 to the mass of the piezoelectric element 120, that is, the mass ratio α. For example, the mass ratio α can include 0.25, 0.5, 0.75, 1, 1.5, 2, 2.5, 3, etc. Taking the piezoelectric cantilever beam shown in FIG. 10 as an example, several exemplary first-order electrodes 130 - 1 and second-order electrodes 130 - 2 are provided to describe in detail the specific implementation of the mass ratio.

Fig. 11A is a schematic diagram of an exemplary primary electrode 130-1 according to some embodiments of the present specification. Fig. 11B is a schematic diagram of an exemplary secondary electrode 130-2 according to some embodiments of the present specification.

As shown in FIG11A , curve 11 is a contour curve of the first-order electrode 130-1 when the mass block model 140 is added with a mass ratio α=0.5, curve 12 is a contour curve of the first-order electrode 130-1 when the mass block model 140 is added with a mass ratio α=1, and curve 13 is a contour curve of the first-order electrode 130-1 when the mass block model 140 is added with a mass ratio α=2. As shown in FIG11B , curve 14 is the contour curve of the secondary electrode 130-2 when the mass block model 140 is added with a mass ratio α=0.5, curve 15 is the contour curve of the secondary electrode 130-2 when the mass block model 140 is added with a mass ratio α=1, and curve 16 is the contour curve of the secondary electrode 130-2 when the mass block model 140 is added with a mass ratio α=2.

In some embodiments, as the mass ratio α changes, the shape of the electrode 130 may also change accordingly. For example, the greater the mass ratio α of the mass block model 140 to the mass of the piezoelectric component 120, the flatter the width of the electrode 130 changes. Exemplarily, as shown in FIG11A , from curve 11 to curve 13, the greater the mass ratio α of the mass block model 140 to the mass of the piezoelectric component 120, the smaller the curvature of the contour curve of the first-order electrode 130-1, that is, the contour curve of the first-order electrode 130-1 changes flatter.

For another example, as shown in FIG11B, from curve 14 to curve 16, the mass ratio α of the mass block model 140 to the mass of the piezoelectric component 120 becomes larger and larger, and the curvature of the contour curve of the secondary electrode 130-2 decreases from the fixed area 124 to the transition point 133. Moreover, the curvature of the contour curve of the secondary electrode 130-2 increases from the transition point 133 to the vibration output area 123, and the curvature when decreasing is also smaller and smaller, that is, the change of the contour curve of the secondary electrode 130-2 is becoming more and more straight. The specific implementation method of the contour curve of the above-mentioned electrode 130 can refer to the relevant description in FIGS. 5A-5D, which will not be repeated here.

In some embodiments, when the piezoelectric element 120 is attached with a mass block model 140, the mass relationship between the piezoelectric element 120 and the mass block model 140 may be ignored, and the contour curve of the electrode 130 may be determined based on the vibration structure of the piezoelectric element 120, and the piezoelectric element 120 may also be modally controlled. The specific implementation of electrode design without considering the mass ratio may refer to the relevant description in the following FIGS. 12 to 13D, which will not be repeated here.

FIG. 12 is a comparative diagram of frequency response curves of exemplary piezoelectric elements according to some embodiments of the present specification.

As shown in FIG. 12 , curve 17 is a frequency response curve of the piezoelectric element 120 when the electrode 130 completely covers a surface of the piezoelectric element 120 (ie, the electrode 130 and the piezoelectric element 120 overlap and are both rectangular) and the mass block model 140 is added. Curve 18 is a frequency response curve of the piezoelectric element 120 with the mass block model 140 having an additional mass ratio α=0.5 and using the first-order electrode 130-1 as shown in FIG. 11A , Curve 19 is a frequency response curve of the piezoelectric element 120 with the mass block model 140 having an additional mass ratio α=1 and using the first-order electrode 130-1 as shown in FIG. 11A , Curve 20 is a frequency response curve of the piezoelectric element 120 with the mass block model 140 having an additional mass ratio α=2 and using the first-order electrode 130-1 as shown in FIG. 11A . 1, curve 21 is the frequency response curve of the piezoelectric element 120 using the first-order electrode 130-1 as shown in FIG5A (i.e., the electrode shape calculated when the mass block model 140 is not attached) but still adding the mass block model 140 with a mass ratio α=0.5, and curve 22 is the frequency response curve of the piezoelectric element 120 adding the mass block model 140 with a mass ratio α=0.5 and using the second-order electrode 130-2 as shown in FIG11B.

As shown in FIG. 12 , the curve 17 has a first-order peak and a second-order valley, which can reflect that when the electrode 130 completely covers a surface of the piezoelectric element 120 (ie, the electrode 130 overlaps with the piezoelectric element 120 ) and the piezoelectric element 120 with the additional mass block model 140 still has multiple modes.

As shown in FIG12 , after adopting the first-order electrode 130-1 designed under the additional mass block model 140, the piezoelectric component 120 shown in curves 18 to 20 starts from the first-order peak and smoothly transitions to the second-order peak frequency (such as around 1000 Hz), and then a weak jump occurs at the second-order peak frequency, and then continues to smoothly transition to the third-order valley. In addition, at the second-order peak frequency and the third-order peak frequency (such as around 7000 Hz), the amplitude of the frequency response curve of the piezoelectric element 120 shown in curves 18 to 20 is significantly reduced.

Moreover, as the mass ratio α increases, the frequency corresponding to the first-order peak of the frequency response curve of the piezoelectric element 120 shown in curves 18-curve 20 becomes lower and lower, and the amplitude becomes lower and lower from the first-order peak, and the change trend of the frequency response curve becomes flatter and flatter after jumping at the second-order peak frequency. This phenomenon can reflect that the larger the mass ratio α is, the better the modal control effect of the piezoelectric component 120 of the first-order electrode 130-1 designed under the additional mass block model 140 is.

As shown in FIG12 , after adopting the first-order electrode 130-1 designed under the unattached mass block model 140, the frequency response curve of the piezoelectric element of the mass block model 140 with an added mass ratio α=0.5 shown in curve 21 can smoothly transition at the frequency corresponding to the second-order valley, but the amplitude and bandwidth of the jump at the second-order peak frequency are significantly increased. This phenomenon can reflect that the first-order electrode 130-1 designed under the unattached mass block model 140 can still achieve modal control of the second-order valley of the piezoelectric element 120, but the suppression effect on high-order modes may be weakened.

After adopting the second-order electrode 130-2 designed under the additional mass block model 140, the frequency response curve of the piezoelectric element 120 shown in curve 22 is similar to the frequency response curve of the piezoelectric element 120 without the additional mass block model 140 shown in curve 3 in Figure 6 above. It is in the second-order vibration mode from the low-frequency stage (such as 0~100Hz) and produces a narrow-band jump of the curve at the first-order peak frequency (such as between 100Hz and 200Hz), reducing the amplitude of the first-order peak. After the peak frequency, the second-order vibration mode is maintained until the third-order peak frequency (e.g., between 6000 Hz and 7000 Hz). This phenomenon reflects that the piezoelectric element 120 with the second-order electrode 130-2 (and the potentials of the two envelope regions are opposite) designed under the mass block model 140 with an additional mass ratio α=0.5 can control the second-order vibration mode.

FIG. 13A is a vibration mode diagram of the piezoelectric component 120 at the second-order valley frequency when the electrode completely covers a surface of the piezoelectric element 120 (i.e., the electrode 130 overlaps with the piezoelectric element 120) according to the additional mass block model 140 shown in some embodiments of this specification; FIG. 13B is a vibration mode diagram of the piezoelectric component 120 with the first-order electrode 130-1 designed under the additional mass block model 140 shown in some embodiments of this specification. FIG13C is a vibration mode diagram at the second-order valley frequency of the piezoelectric component 120 in which the second-order electrode 130-2 is designed using the unattached mass block model 140 according to some embodiments of the present specification; FIG13D is a vibration mode diagram at the second-order valley frequency of the piezoelectric component 120 in which the second-order electrode 130-2 is designed using the attached mass block model 140 according to some embodiments of the present specification.

In conjunction with Figure 12 and Figure 13A-13D, at the second-order valley frequency (for example, 1411 Hz), when the electrode completely covers one surface of the piezoelectric element (that is, the rectangular electrode overlaps with the rectangular piezoelectric element), the vibration response of the piezoelectric element 120 of the added mass block model 140 during the vibration process fluctuates greatly, the frequency response curve is not flat, and the vibration output area 123 may form nodes at certain frequencies, affecting the effect of the acoustic output. When the first-order electrode 130-1 designed under the additional mass block model 140 (or the first-order electrode 130-1 and the second-order electrode 130-2 designed under the additional mass block model 140) or the first-order electrode 130-1 designed under the non-additional mass block model 140 is used, during the vibration process of the piezoelectric element 120 of the additional mass block model 140, the vibration response fluctuation of the piezoelectric component 120 is smaller, the frequency response curve is flatter, and it is less likely to form nodes.

In addition, as shown in FIG13C , when the first-order electrode 130-1 designed without the attached mass block model 140 is used, if the piezoelectric element 120 with the attached mass block model 140 is in the vibration process, its vibration mode will show a trend of transitioning to the second-order vibration mode. This trend can reflect that the first-order electrode 130-1 designed without the attached mass block model 140 can still achieve modal control of the piezoelectric element 120, but its suppression effect on high-order modes may be weakened.

In the embodiment of the present specification, the electrode 130 is designed based on the mass ratio α of the mass block model 140 and the piezoelectric element 120, so that the piezoelectric element 120 can generate a more accurate excitation force of a specific mode, further improving the modal control effect. In addition, the amplitude of the frequency response curve of the piezoelectric element 120 at a fixed frequency can be reduced to avoid the formation of nodes in the vibration output area 123 of the piezoelectric element 120, further improving the working reliability of the acoustic device 100.

In some embodiments, the piezoelectric element 120 may include a piezoelectric plate or a piezoelectric film. In some embodiments, the shape of the electrode 130 may be determined according to the size of the piezoelectric plate or the piezoelectric film and the vibration mode function of the vibrating structure. For example, the electrode 130 covered on the piezoelectric plate or the piezoelectric film may be designed as a plurality of two-dimensionally distributed discrete electrode units (also referred to as "two-dimensional electrodes"), so that the piezoelectric element 120 generates a specific mode.

Taking the piezoelectric element 120 shown in FIG. 4 as an example, exemplary discrete electrode units 134 and continuous electrodes are provided to describe in detail the specific implementation of the two-dimensional electrode design.

In some embodiments, the electrode 130 may include a plurality of two-dimensionally distributed discrete electrode units 134. In some embodiments, the plurality of discrete electrode units 134 may be configured as conductive materials separated from each other and distributed on the surface of the piezoelectric element 120. In some embodiments, the shape of the discrete electrode unit 134 may include one or any combination of circular, triangular, quadrilateral, irregular, etc.

Figure 14A is a partial structural schematic diagram of an exemplary two-dimensional electrode 130 shown in some embodiments of the present specification; Figure 14B is a partial structural schematic diagram of an exemplary two-dimensional electrode 130 shown in some embodiments of the present specification; Figure 14C is a partial structural schematic diagram of an exemplary two-dimensional electrode 130 shown in some embodiments of the present specification; Figure 14D is a partial structural schematic diagram of an exemplary two-dimensional electrode 130 shown in some embodiments of the present specification.

FIG14A shows a quarter of a square piezoelectric layer, where the piezoelectric layer 122 (e.g., a square piezoelectric sheet with a size of 18×18×0.09 mm) overlaps with a substrate 121 (e.g., a steel substrate with a size of 18×18×0.05 mm), and the edges of the substrate are fixed areas 124. FIG14B shows a quarter of a square piezoelectric layer, where the piezoelectric layer 122 (e.g., a square piezoelectric sheet with a size of 18×18×0.09 mm) covers a substrate 121 (e.g., a steel substrate with a size of 23×23×0.05 mm), and the covering area of the piezoelectric layer 122 is smaller than the surface area of the substrate 121 covering the piezoelectric layer, and the edges of the substrate are fixed areas 124. FIG. 14C and FIG. 14D respectively show a rectangular piezoelectric layer, wherein the piezoelectric layer 122 (e.g., a rectangular piezoelectric plate with a size of 40×20×0.5 mm) overlaps with a substrate 121 (e.g., a steel substrate with a size of 40×20×0.1 mm), and the edges of the substrate are fixed regions 124. The rectangular piezoelectric plate shown in FIG. 14D is a (3,1) mode. The "3" in the "(3,1) mode" in this specification refers to a third-order mode in the length direction, that is, when the rectangular piezoelectric plate is simplified to a cantilever beam along the length direction (ignoring the existence of the width), it has a third-order mode; "1" refers to a first-order mode in the width direction, that is, when the rectangular piezoelectric plate is simplified to a cantilever beam along the width direction (ignoring the existence of the length), it has a first-order mode.

In some embodiments, among the plurality of discrete electrode units 134, the gap between two adjacent discrete electrode units 134 at the center of the piezoelectric layer 122 is smaller than the gap between two adjacent discrete electrode units 134 at the boundary of the piezoelectric layer 122. The "center of the piezoelectric layer 122" mentioned here may be the geometric center of the piezoelectric layer 122, or the vibration amplitude output position of each order mode of the piezoelectric layer 122, or the center of the vibration output region 123. For example, when the piezoelectric layer 122 is a (3,1) mode, the center of the piezoelectric layer 122 may include three vibration centers, each corresponding to a first-order vibration mode. Correspondingly, the "boundary of the piezoelectric layer 122" mentioned here can be the geometric boundary of the piezoelectric layer 122, or the region where the vibration output of each mode of the piezoelectric layer 122 is the smallest, or the boundary of the fixed region 124. For example, when the piezoelectric layer 122 is a (3,1) mode (i.e., a third-order mode in the length direction and a first-order mode in the width direction), the boundary of the piezoelectric layer 122 can be the boundary of the region corresponding to each vibration mode. For example, as shown in FIGS. 14A to 14C , the gap between two adjacent discrete electrode units 134 at the geometric center of the piezoelectric layer 122 is a distance D1, and the gap between two adjacent discrete electrode units 134 at the boundary may be a distance D2, and the distance D1 is smaller than the distance D2. For another example, as shown in FIG. 14D , the gap between two adjacent discrete electrode units 134 at each vibration center of the piezoelectric layer 122 is a distance D1, and the gap between two adjacent discrete electrode units 134 at the boundary of the region corresponding to the vibration center may be a distance D2, and the distance D1 is smaller than the distance D2. In some embodiments, the gap between two adjacent discrete electrode units gradually increases from the center to the boundary of the piezoelectric layer 122. For example, the gap between two adjacent discrete electrode units close to the center of the piezoelectric layer 122 is smaller than the gap between two adjacent discrete electrode units far from the center of the piezoelectric layer 122.

In some embodiments, the area size of the discrete electrode unit 134 may be related to the vibration displacement of the region in which it is located at a specific frequency (e.g., first-order peak, second-order peak). The vibration displacement refers to the distance change of the piezoelectric layer 122 compared to the horizontal plane when it is not vibrating during the vibration process. In some embodiments, the area of the first discrete electrode unit 1341 at the center of the piezoelectric layer 122 is larger than the area of the second discrete electrode unit 1342 at the boundary of the piezoelectric layer 122. For example, as shown in Figures 14A-14D, since the first discrete electrode unit 1341 is closer to the vibration output area 123 than the second discrete electrode unit 1342, the displacement of the first discrete electrode unit 1341 is greater than the displacement of the second discrete electrode unit 1342 during the vibration process, and the area of the first discrete electrode unit 1341 can be greater than the area of the second discrete electrode unit 1342.

In some embodiments, the area size of the discrete electrode unit 134 can be determined according to the difference (e.g., displacement ratio) between the vibration displacement of the region where the discrete electrode unit 134 is located and the maximum displacement of the piezoelectric layer 122 at a specific frequency (e.g., first-order peak, second-order peak). Exemplarily, the piezoelectric layer 122 can be dispersed into m×n piezoelectric regions, i.e., m×n discrete electrode units 134. Based on the difference between the displacement of each piezoelectric region and the maximum displacement of the piezoelectric layer 122, the piezoelectric region is scaled proportionally to determine the area of the discrete electrode unit 134 of the piezoelectric region.

In some embodiments, the electric potential of the discrete electrode unit 134 may be related to the displacement direction of the piezoelectric region in which it is located. Exemplarily, as shown in FIG14D , during the vibration of the piezoelectric component 120, if the displacement direction of the third discrete electrode unit 1343 is opposite to the maximum displacement direction of the piezoelectric layer 122, and the displacement direction of the fourth discrete electrode unit 1344 is the same as the maximum displacement direction of the piezoelectric layer 122, then the electric potential direction of the third discrete electrode unit 1343 is opposite to the electric potential direction of the fourth discrete electrode unit 1344.

The following uses the size of the piezoelectric element 120 and the substrate shown in FIG. 14A and FIG. 14B as an example to describe the difference in frequency response curves when discrete electrode units of different shapes or numbers are covered thereon.

Figure 15A is a comparative schematic diagram of the frequency response curves of the exemplary piezoelectric element shown in some embodiments of the present specification; Figure 15B is a comparative schematic diagram of the frequency response curves of the exemplary piezoelectric element shown in some embodiments of the present specification; Figure 15C is a schematic diagram of the vibration displacement of the piezoelectric component covering the integral electrode at 5380.3 Hz according to some embodiments of the present specification; Figure 15D is a schematic diagram of the vibration displacement of the piezoelectric element covering the 8×8 discrete electrode unit at 5380.3 Hz according to some embodiments of the present specification.

As shown in FIG15A , curve 23 is a frequency response curve of the piezoelectric element 120 when the piezoelectric layer 122 as shown in FIG14A overlaps with the substrate 121 and the electrode 130 completely covers one surface of the piezoelectric element 120 (i.e., the entire electrode); curve 24 is a frequency response curve of the piezoelectric element 120 covered with 8×8 discrete electrode units 134 when the piezoelectric layer 122 as shown in FIG14A overlaps with the substrate 121; curve 25 is a frequency response curve of the piezoelectric element 120 covered with 32×32 discrete electrode units 134 when the piezoelectric layer 122 as shown in FIG14A overlaps with the substrate 121.

As shown in FIG15A , the frequency response curve of the piezoelectric element 120 shown by curve 23 produces a resonance valley, and split vibration is generated at the frequency corresponding to the resonance valley (e.g., around 5380.3 Hz). This phenomenon can be reflected in that when the electrode 130 completely covers one surface of the piezoelectric element 120, the central area of the piezoelectric layer 122 is in anti-phase with the surrounding vibrations and has the same vibration area, which easily causes the radiated sound pressure of the piezoelectric element 120 to cancel each other out in anti-phase in the vibration output area, making it difficult to output vibration.

The frequency response curve of the piezoelectric element 120 shown in curves 24 and 25 can form a smooth sound pressure level frequency response curve between the first-order peak (such as 3500 Hz) and the second-order peak (such as around 10000 Hz), and increase the amplitude near the resonance valley frequency. This phenomenon can reflect that the two-dimensional electrode 130 can expand the bandwidth of the piston vibration of the piezoelectric element 120, so that it can still maintain the first-order piston vibration at the frequency corresponding to the original resonance valley (such as around 5380.3 Hz), and effectively output the radiated sound pressure, thereby realizing modal control. The "piston vibration" in this specification refers to the situation that each area of the piezoelectric element 120 (such as a piezoelectric plate) vibrates up and down at the same time (with the same displacement direction), just like a piston.

In addition, the low-frequency amplitude of the frequency response curve of the piezoelectric element 120 shown in curve 24-curve 25 before the first-order peak (such as before 2000 Hz) is also improved, and the overall bandwidth of the second-order peak and the subsequent resonance valley (such as after 10000 Hz) is also reduced. This phenomenon can reflect that the two-dimensional electrode 130 can enhance the low-frequency response of the piezoelectric element 120 and suppress the natural mode vibration type of the piezoelectric component 120 at the second-order peak frequency.

Furthermore, the frequency response curve of the piezoelectric element 120 shown in curve 25 has a higher low-frequency response amplitude before the first-order peak (such as before 2000 Hz) than the frequency response curve of the piezoelectric element 120 shown in curve 24, and further suppresses the amplitude and bandwidth at the second-order peak frequency (such as around 10000 Hz). This phenomenon can reflect that compared with the 8×8 two-dimensional electrode 130, the piezoelectric element 120 using the 32×32 two-dimensional electrode 130 can have a higher low-frequency response and can also suppress high-frequency modes.

As shown in FIG15B , curve 23′ is the frequency response curve of the piezoelectric element 120 when the coverage area of the piezoelectric layer 122 as shown in FIG14B is smaller than the surface area of the substrate 121 covering the piezoelectric layer, and the electrode 130 completely covers one surface of the piezoelectric element 120 (i.e., the entire electrode); curve 24′ is the frequency response curve of the piezoelectric element 120 when the coverage area of the piezoelectric layer 122 as shown in FIG14B is smaller than the surface area of the substrate 121 covering the piezoelectric layer. Curve 25' is a frequency response curve of the piezoelectric element 120 covered with 8×8 discrete electrode units 134 when the coverage area of the piezoelectric layer 122 is smaller than the surface area of the substrate 121 covering the piezoelectric layer as shown in FIG14B . Curve 25' is a frequency response curve of the piezoelectric element 120 covered with 32×32 discrete electrode units 134 when the coverage area of the piezoelectric layer 122 is smaller than the surface area of the substrate 121 covering the piezoelectric layer as shown in FIG14B .

As shown in FIG15B , the frequency response curve of the piezoelectric element 120 shown in curve 23′ generates split vibration at 4189.8 Hz, and the vibration mode is similar to curve 23, so that the sound pressure in the vibration output area cancels each other out in anti-phase, forming a resonance valley. According to curves 24′ and 25′, the two-dimensional electrode can realize the expansion of the piston vibration frequency band, and the piston vibration is still in the original resonance valley frequency point, so that the sound pressure level smoothly transitions in this frequency band. The frequency response curve of the piezoelectric element 120 shown in curve 23′ is a straight curve at the sound pressure level near 6000 Hz after the second-order peak, and after the two-dimensional electrode is used, curves 24′ and 25′ form a resonance valley. The reason for this phenomenon is that for the whole electrode, the vibration mode here is the resonance of the part of the substrate 121 that exceeds the piezoelectric layer 122, thereby outputting vibration. The two-dimensional electrode changes the vibration mode of the piezoelectric layer 122, and when coupled with the elasticity provided by the edge substrate 121, a vibration mode of anti-phase vibration is formed in the middle area and the surrounding area, and anti-phase cancellation of sound pressure is generated in the vibration output area, which is manifested as a resonance valley on the curve, and also has a certain impact on the directivity.

As shown in Figures 15C and 15D, when covering the whole electrode, the piezoelectric element 120 generates split vibration at 5380.3 Hz, and the vibrations in the middle area and the surrounding areas are opposite in phase and have the same area, resulting in anti-phase cancellation of the sound pressure in the vibration output area; while when covering the two-dimensional electrode of the 8×8 discrete electrode unit 134, the piezoelectric component 120 still vibrates as a piston at 5380.3 Hz, effectively outputting the sound pressure, which significantly improves the amplitude of the sound pressure level in the vibration output area.

FIG. 16A is a first-order modal vibration shape diagram of the piezoelectric component 120 when the upper electrode of the rectangular piezoelectric component 120 is completely covered (i.e., the entire electrode) according to some embodiments of the present specification; FIG. 16B is a vibration shape diagram of the piezoelectric component 120 at a high frequency when the upper electrode of the rectangular piezoelectric component 120 is completely covered (i.e., the entire electrode) according to some embodiments of the present specification; FIG. 16C is a vibration shape diagram of the piezoelectric component 120 at a high frequency according to some embodiments of the present specification FIG16D is a vibration mode diagram at high frequency of a piezoelectric element 120 in which 16×8 discrete electrode units 134 of two-dimensional electrodes 130 are used on a rectangular piezoelectric element 120 as shown in some embodiments of the present specification; FIG16D is a vibration mode diagram at high frequency of a piezoelectric element 120 in which 32×16 discrete electrode units 130 of two-dimensional electrodes 130 are used on a rectangular piezoelectric element 120 as shown in some embodiments of the present specification.

FIG16A shows the first-order mode of the rectangular piezoelectric element 120 using the integral electrode at 6907 Hz; the vibration mode of the rectangular piezoelectric element 120 using the integral electrode at a higher frequency of 18326 Hz is shown in FIG16B. By covering the two-dimensional electrode 130, the vibration mode at 18326 Hz presents a first-order vibration mode similar to that of FIG16A. Since 32×16 discrete electrode units are more than 16×8 discrete electrode units and are closer to continuous changes, the vibration mode of the piezoelectric element 120 covering 32×16 discrete electrode units at 18326 Hz is closer to the first-order vibration mode.

In the embodiment of the present specification, the design of the two-dimensional electrode 130 is realized by using a two-dimensional distribution of multiple discrete electrode units 134, so that the piezoelectric element 120 can only output a specific mode vibration shape, further improving the sound characteristics of the acoustic device 100.

Furthermore, the frequency response curve of the piezoelectric element 120 can be more stable, thereby preventing the vibration of the middle area of the piezoelectric element 120 from vibrating in opposite phase with the surrounding areas, thereby preventing the vibration output area 123 from forming a node, thereby improving the working reliability of the acoustic device 100.

Figure 17A is a schematic diagram of the design concept of a discrete electrode unit 134 of an exemplary two-dimensional electrode 130 shown in some embodiments of the present specification; Figure 17B is a structural schematic diagram of a discrete electrode unit 134 of an exemplary two-dimensional electrode 130 shown in some embodiments of the present specification; Figure 17C is a shape schematic diagram of a first-order electrode 130-1 corresponding to a rectangle equivalent to a fixed support beam at both ends shown in some embodiments of the present specification.

As shown in FIG17A , the piezoelectric component 120 can be divided into 16 rectangles in the length direction (such as the horizontal direction in FIG17A ) (divided by 15 dotted lines), wherein the 16 rectangles all have the width of the piezoelectric component 120 as the length and equally divide the length of the piezoelectric component 120; similarly, the piezoelectric component 120 can be divided into 8 rectangles in the width direction (such as the vertical direction in FIG17A ) (divided by 7 dotted lines). The 16 rectangles in the length direction and the 8 rectangles in the width direction can be equivalent to two-end clamped beams. As shown in FIG7 , along the length direction, the width of the rectangular clamped beam gradually increases from 0 from one fixed area 124 to another fixed area 124 and then gradually decreases to 0, forming a "shuttle shape". In some embodiments, the increase or decrease in width may include a gradient increase or decrease in width, a linear increase or decrease, a curved increase or decrease, or any combination thereof. It should be understood that FIG17C only shows the shape of the electrode in the length direction, and each rectangular clamped beam in the width direction may also be a similar shape. In some embodiments, according to the shape of the first-order electrode 130-1 shown in FIG17C, a first shape 171 of a plurality of discrete electrode units 134 in the length direction (such as 16 columns of shuttles in FIG17A) and a second shape 172 of a plurality of discrete electrode units 134 in the width direction (such as 8 rows of shuttles in FIG17A) are determined, thereby determining a two-dimensional electrode 130 based on the first shape 171 and the second shape 172. As shown in FIG17B, the two-dimensional electrode 130 may be an overlapping region of the first shape 171 and the second shape 172, and each overlapping region may be a discrete electrode unit 134.

FIG. 18 is a vibration mode diagram of the piezoelectric component 120 covering the two-dimensional electrode 130 shown in FIG. 17B according to some embodiments of the present specification.

As shown in FIG18 , the vibration mode of the piezoelectric component 120 covered by the two-dimensional electrode 130 shown in FIG17B is still close to the first-order vibration mode at the high frequency band (such as 18326 Hz), so that the sound pressure can be effectively output, and the amplitude of the sound pressure level in the vibration output area is significantly improved. Compared with the two-dimensional electrode shown in FIG14C (the vibration mode diagram is shown in FIG16C and FIG16D ), the two-dimensional electrode 130 shown in FIG17B can also achieve modal control.

In some embodiments, discrete electrode units have the problem that the circuits between the electrodes are difficult to connect, which makes mass production difficult. Therefore, the electrodes can be changed from discrete to connected, which is beneficial to the production of printing screens and the connection of electrodes, and is suitable for mass production. For example, the electrode 130 can include a two-dimensionally distributed continuous electrode 135, and the continuous electrode can include a plurality of hollow areas 136.

In some embodiments, the continuous electrode 135 can be configured as a continuous conductive material disposed on the surface of the piezoelectric element 120, and the hollow region 136 can be configured as a region where no conductive material is disposed. Compared with the multiple discrete electrode units 134 shown in the above-mentioned Figures 14A-14D or Figure 17B, the continuous electrode 135 can be understood as an electrode 130 composed of discretely distributed electrodes connected as a whole, and then the continuous electrode 135 is dispersed into multiple regions of two-dimensional distribution by providing multiple hollow regions 136, thereby realizing the design of the electrode 130.

Figure 19A is a partial structural schematic diagram of an exemplary two-dimensionally distributed continuous electrode 130 according to some embodiments of the present specification; Figure 19B is a partial structural schematic diagram of an exemplary two-dimensionally distributed continuous electrode 130 according to some embodiments of the present specification; Figure 19C is a partial structural schematic diagram of an exemplary two-dimensionally distributed continuous electrode 130 according to some embodiments of the present specification.

As shown in FIGS. 19A-19C , the two-dimensional electrode 130 (a quarter two-dimensional electrode) may include a two-dimensionally distributed continuous electrode 135 , and the continuous electrode 135 may include a plurality of hollow regions 136 .

In some embodiments, the shape of the hollow region 136 may be the same as or different from the shape of the piezoelectric element 120. In some embodiments, the shape of the hollow region 136 may include one or any combination of circular, triangular, quadrilateral, pentagonal, hexagonal or irregular shapes. For example, the continuous electrode 135 shown in FIG. 19A may include a plurality of square hollow regions 136; the continuous electrode 135 shown in FIG. 19B may include a plurality of hexagonal hollow regions 136; the continuous electrode 135 shown in FIG. 19C may include a plurality of quadrilateral hollow regions and a plurality of octagonal hollow regions.

In some embodiments, the distance between two adjacent hollow regions 136 at the center of the piezoelectric layer 122 may be greater than the distance between two adjacent hollow regions 136 at the boundary of the piezoelectric layer. For example, as shown in FIGS. 19A-19C , the distance between two adjacent hollow regions 136 is smaller as they are closer to the boundary.

In some embodiments, the area of the first hollow region 1361 at the center of the piezoelectric layer 122 is smaller than the area of the second hollow region 1362 at the boundary of the piezoelectric layer. As shown in FIGS. 19A-19C , the first hollow region 1361 is closer to the center of the piezoelectric layer 122 than the second hollow region 1362, and the area of the first hollow region 1361 is smaller than the area of the second hollow region 1362.

In some embodiments, the piezoelectric layer 122 may be divided into a plurality of two-dimensionally distributed piezoelectric regions of the same size, each of which may include a hollow region 136, and the hollow region 136 may be located at the center of the piezoelectric region, and the continuous electrode 135 in the piezoelectric region may be located at the edge of the piezoelectric region to form a continuously connected electrode with the continuous electrodes 135 of other piezoelectric regions. For example, as shown in FIGS. 19A-19C , the hollow region 136 may be disposed at the center of the piezoelectric region to make the electrode 130 at the edge of the piezoelectric region continuous.

In some embodiments, the area size of the hollow region 136 may be related to the vibration displacement of the piezoelectric region in which it is located at a specific frequency (e.g., a first-order peak, a second-order peak). In some embodiments, the area of the hollow region 136 in each piezoelectric region may be determined based on the difference between the vibration displacement of the piezoelectric region at a specific frequency (e.g., a first-order peak, a second-order peak) and the maximum displacement of the piezoelectric layer 122 (e.g., a vibration displacement ratio). For example, the greater the difference between the vibration displacement and the maximum displacement of the piezoelectric layer 122, the larger the area of the hollow region 136. FIG. 20 is a comparative schematic diagram of the frequency response curves of exemplary piezoelectric elements shown in some embodiments of the present specification.

As shown in FIG20 , curve 26 is a frequency response curve of the piezoelectric element 120 using an integral electrode, curve 27 is a frequency response curve of the piezoelectric element 120 of the two-dimensional electrode 130 covering 32×32 discrete electrode units, and curve 28 is a frequency response curve of the piezoelectric element 120 covering 32×32 two-dimensionally distributed continuous electrodes 130. According to curves 27 and 28, the modal control effect of the two-dimensionally distributed continuous electrode 130 is somewhat different from the modal control effect of the electrode 130 composed of two-dimensionally distributed discrete electrode units. For example, the resonance valley of the electrode 130 composed of two-dimensionally distributed continuous electrode units at 12128 Hz moves forward to 7829.4 Hz. The shift of the resonance valley may be related to the hollow shape and density of the electrode 130, but it still shows a certain modal control effect on the piezoelectric element 120.

In the embodiment of this specification, the continuous electrode 135 includes a plurality of hollow regions 136, so that the covering surface of the two-dimensional electrode 130 can be changed from discrete to connected, which is beneficial to the generation, manufacture and use of the two-dimensional electrode and is more suitable for mass production.

It should be understood that, similar to the one-dimensional electrode, the design of the two-dimensional electrode can also limit the effective area of the electrode covered on the piezoelectric layer (e.g., piezoelectric plate, piezoelectric film) by the shape and area of the piezoelectric region in the piezoelectric layer. For example, the piezoelectric plate or piezoelectric film includes a piezoelectric region made of a piezoelectric material and a non-piezoelectric region made of a non-piezoelectric material, and the sum of the areas of the piezoelectric region and the non-piezoelectric region is equal to the coverage area of the piezoelectric plate or piezoelectric film on the substrate, and the electrode completely covers the piezoelectric plate or piezoelectric film (i.e., the electrode and the piezoelectric plate or piezoelectric film overlap). The pattern of the piezoelectric region can be a two-dimensional electrode design pattern shown in any of Figures 14A, 14B, 14C, 14D, 17A, 17B, 19A, 19B or 19C, and the portion on the substrate other than the piezoelectric region is a non-piezoelectric region. Therefore, in the two-dimensional electrode design, the modal control of the piezoelectric component can be achieved by the piezoelectric region area < the coverage area of the piezoelectric layer (for example, the piezoelectric plate, the piezoelectric film) = the coverage area of the electrode ≤ the surface area of the substrate covering the piezoelectric layer.

In some embodiments, the electrode 130 may be covered on one surface of the piezoelectric layer 122, or on both surfaces of the piezoelectric layer. For example, the electrode 130 may also be covered on another surface opposite to the above-mentioned surface, and the covering area of the electrode 130 on the other surface may be less than or equal to the area of the surface. In other words, the design of the electrode 130 may be implemented on two opposite surfaces, thereby controlling the mode of the piezoelectric element 120. The design of the electrode 130 on the other surface may refer to the design of any of the electrodes 130 in the above-mentioned Figures 5A, 5C, 8A-8D, 11A, 11B, 14A-14D, 17B, 19A-19C, which will not be repeated here.

In some embodiments, the piezoelectric element 120 may further include a vibration regulating element. The vibration regulating element may be configured as a device that changes the vibration state of the acoustic device (for example, by changing the mass, elasticity or damping of one or more elements in the acoustic device to adjust the output vibration mode). In some embodiments, the vibration regulating element may be connected to the vibration output region 123 of the piezoelectric element 120 and adjust the vibration output by the piezoelectric element 120. In some embodiments, the vibration regulating element may include one or any combination of a connector (such as a housing, etc.), a mass block (such as a metal mass block, etc.), an elastic member (such as a traction rope, a spring sheet, etc.), etc. The connecting member can connect the piezoelectric element 120 to other elements, and the elastic member can provide elastic force to the piezoelectric element 120, thereby changing the vibration state of the piezoelectric element 120.

In some embodiments, the vibration control element may include a mass block 170, which is physically (e.g., mechanically or electromagnetically) connected to the vibration output area 123. In some embodiments, the mass block 170 may be an element with a certain mass. In some embodiments, the mass block 170 may include one or any combination of metal mass blocks, rubber mass blocks, plastic mass blocks, etc. In some embodiments, the mass block 170 may be used to change the mode of the piezoelectric element 120.

In some embodiments, the acoustic device 100 further includes a connector 171, which connects the vibration element 110 and the piezoelectric element 120. In some embodiments, the connector can be configured as an element with a certain rigidity, and the connector 171 can include one or any combination of a vibration transmitting sheet, an elastic member, etc. In some embodiments, the mass block 170 can be connected to the vibration output area 132 through the connector 171.

The following provides an exemplary acoustic device by taking the piezoelectric element 120 shown in FIG. 3 as an example, and describes in detail the specific implementation of the piezoelectric cantilever beam, the mass block 170 and the connector 171.

FIG21 is a schematic diagram of the structure of an exemplary acoustic device according to some embodiments of the present specification. In some embodiments, the acoustic device may include at least one piezoelectric element 120, the vibration output region of each piezoelectric element 120 may be connected to a vibration element 110, and each vibration element 110 is connected to a vibration control element (e.g., a mass block 170). As shown in FIG21, the acoustic device may include two piezoelectric elements 120 covered with a first-order electrode 130-1, the vibration output region of each piezoelectric element 120 is connected to the vibration element 110, and the vibration element 110 is connected to the vibration control element (e.g., a mass block 170) through at least one connector 171.

In some embodiments, the length of the piezoelectric element 120 in the acoustic device can be shortened to reduce the mode of the piezoelectric element 120. For example, the acoustic device can use the elasticity provided by the connector 171 and the mass block 170 to construct a low-frequency peak, thereby using a short piezoelectric cantilever beam (such as the piezoelectric component 120 shown in FIG. 21) to reduce the mode and form a flat frequency response curve between the low-frequency peak of the frequency response curve and the first-order modal peak (higher frequency).

FIG. 22 is a comparative diagram of frequency response curves of exemplary piezoelectric elements according to some embodiments of the present specification.

As shown in FIG22 , curve 29 is a frequency response curve of the piezoelectric element 120 using an integral electrode having a length of 8 mm, curve 30 is a frequency response curve of the piezoelectric element 120 using a first-order electrode 130-1 having a length of 8 mm; curve 31 is a frequency response curve of the piezoelectric element 120 using a first-order electrode 130-1 having a length of 10 mm; and curve 32 is a frequency response curve of the piezoelectric element 120 using a first-order electrode 130-1 having a length of 12 mm.

As shown in FIG22 , the frequency response curve corresponding to the piezoelectric component 120 shown in curve 29 generates a second-order resonance at the second-order modal valley (e.g., 12272 Hz). This phenomenon can reflect that the piezoelectric element 120 using the integral electrode in the acoustic device cannot effectively output vibration, resulting in a resonance valley on its frequency response curve. The resonance valley of the frequency response curve corresponding to the piezoelectric component 120 shown in curves 30 to 32 is improved, and the vibration characteristics of the resonance valley are not affected. This phenomenon can reflect that the design of using the first-order electrode 130-1 in the acoustic device can improve the second-order resonance valley generated by the piezoelectric element 120.

Furthermore, the modal forward shift formed by the piezoelectric cantilever beam (i.e., the piezoelectric component 120) and the vibration plate in the frequency response curve corresponding to the piezoelectric component 120 shown in curve 30-curve 32 can be reflected in the case where the first-order electrode 130-1 design is adopted in the acoustic device. By appropriately extending the length of the piezoelectric element 120 (for example, setting the length of the piezoelectric element 120 to be not less than 8 mm, not less than 10 mm, or not less than 12 mm), the low-frequency sensitivity of the acoustic device can be improved while improving the resonance valley.

FIG. 23A is a vibration mode diagram of an acoustic device using an integral electrode 130 according to some embodiments of the present specification; FIG. 23B is a vibration mode diagram of an acoustic device using a first-order electrode 130-1 according to some embodiments of the present specification.

As shown in FIG23A, at the resonance valley (e.g., 12272 Hz), the vibration output region of the piezoelectric element 120 in the acoustic device using the integral electrode forms a node. As shown in FIG23B, at the resonance valley (e.g., 12272 Hz), the vibration output region of the piezoelectric element 120 in the acoustic device using the first-order electrode 130-1 does not form a node, and presents a first-order vibration mode.

In the embodiment provided in this specification, the design of the electrode 130 can enhance the second-order harmonic valley generated by the frequency response curve corresponding to the piezoelectric element 120 in the acoustic device, and at the same time, a longer piezoelectric element 120 can be used to enhance the low-frequency sensitivity of the acoustic device.

Figure 24 is a schematic diagram of the structure of an exemplary acoustic device according to some embodiments of the present specification.

In some embodiments, as shown in FIG. 24 , the acoustic device 100 may be a piezoelectric suspension beam output configuration, wherein one end of the piezoelectric suspension arm (i.e., the piezoelectric component 120) designed with an electrode is a fixed area 124, and the other end is a vibration output area 123, and the vibration is output to the vibration plate or diaphragm (i.e., the vibration component 110) through the connector 171. In some embodiments, the acoustic device 100 may be a bone conduction audio device (e.g., a bone conduction headset, bone conduction glasses, etc.). In some embodiments, the fixed end of the piezoelectric element 120 may include one or any combination of the outer shell of the bone conduction audio device, the top point of the ear hook, the connection between the ear hook and the board, the temple of the glasses, etc. In some embodiments, the connector 171 may have a certain rigidity and be rigidly connected to the vibration output region of the vibration plate or diaphragm or the piezoelectric suspension arm.

The beneficial effects that the embodiments of this specification may bring include but are not limited to: (1) By forming a modal actuator of a piezoelectric element through electrode design, the piezoelectric element only generates an excitation force of a specific mode to output a specific modal vibration shape, thereby avoiding the formation of nodes at the vibration output point of the piezoelectric element and improving the working reliability of the acoustic device. (2) Compared with the modal control system composed of mechanical structures such as springs, masses, and damping added to a specific area, the embodiments of this specification can achieve modal control of the piezoelectric element based on the electrode design, simplifying the structure of the acoustic device.

The basic concepts have been described above. Obviously, for those with ordinary knowledge in the art, the above detailed disclosure is only for example and does not constitute a limitation of this specification. Although not explicitly stated here, those with ordinary knowledge in the art may make various modifications, improvements and amendments to this specification. Such modifications, improvements and amendments are suggested in this specification, so such modifications, improvements and amendments still belong to the spirit and scope of the exemplary embodiments of this specification.

At the same time, this specification uses specific words to describe the embodiments of this specification. For example, "one embodiment", "an embodiment", and/or "some embodiments" refer to a certain feature, structure or characteristic related to at least one embodiment of this specification. Therefore, it should be emphasized and noted that "one embodiment" or "an embodiment" or "an alternative embodiment" mentioned twice or more in different locations in this specification does not necessarily refer to the same embodiment. In addition, certain features, structures or characteristics in one or more embodiments of this specification can be appropriately combined.

In addition, unless expressly stated in the scope of the patent application, the order of the processing elements and sequences described in this specification, the use of digits, or the use of other names are not used to limit the order of the processes and methods of this specification. Although some of the invention embodiments currently considered useful are discussed in the above disclosure through various examples, it should be understood that such details are only for the purpose of explanation, and the attached patent scope is not limited to the disclosed embodiments. On the contrary, the scope of the patent application is intended to cover all modifications and equivalent combinations that are consistent with the essence and scope of the embodiments of this specification. For example, although the system elements described above can be implemented by hardware devices, they can also be implemented only by software solutions, such as installing the described system on an existing server or mobile device.

Similarly, it should be noted that in order to simplify the description disclosed in this specification and thus help understand one or more embodiments of the invention, in the above description of the embodiments of this specification, multiple features are sometimes combined into one embodiment, drawings or description thereof. However, this disclosure method does not mean that the features required by the subject matter of this specification are more than the features mentioned in the patent application scope. In fact, the features of an embodiment are less than all the features of the single embodiment disclosed above.

In some embodiments, digits are used to describe the quantity of components and attributes. It should be understood that such digits used in the description of the embodiments are modified by the modifiers "approximately", "approximately" or "substantially" in some examples. Unless otherwise specified, "approximately", "approximately" or "substantially" indicate that the digits are allowed to vary by ±20%. Accordingly, in some embodiments, the numerical parameters used in the specification and the scope of the patent application are approximate values, which may change according to the required features of the individual embodiments. In some embodiments, the numerical parameters should consider the specified significant digits and adopt the general digit retention method. Although the numerical domains and parameters used to confirm the breadth of the scope in some embodiments of this specification are approximate values, in specific embodiments, the settings of such numerical values are as accurate as possible within the feasible range.

Each patent, patent application, patent application disclosure, and other materials, such as articles, books, instructions, publications, documents, etc., cited in this specification is hereby incorporated into this specification in its entirety for reference. Except for application history files that are inconsistent with or conflicting with the contents of this specification, and files that limit the broadest scope of the patent application in this specification (currently or subsequently attached to this specification) are also excluded. It should be noted that if the descriptions, definitions, and/or use of terms in the materials attached to this specification are inconsistent or conflicting with the contents described in this specification, the descriptions, definitions, and/or use of terms in this specification shall prevail.

Finally, it should be understood that the embodiments described in this specification are intended only to illustrate the principles of the embodiments of this specification. Other variations may also fall within the scope of this specification. Therefore, as examples and not limitations, alternative configurations of the embodiments of this specification may be considered consistent with the teachings of this specification. Accordingly, the embodiments of this specification are not limited to the embodiments explicitly introduced and described in this specification.

100: Acoustic device 110: Vibration component 120: Piezoelectric component 121: Substrate 122: Piezoelectric layer 123: Vibration output area 124: Fixed area 130: Electrode 130-1: First-order electrode 130-2: Second-order electrode 131: First electrode envelope area 132: Second electrode envelope area 133: Point 134: Discrete electrode unit 135: Continuous electrode 136: Hollow area 140: Mass block model 141: Second vibration output area 170: Mass block 171: Connector 172: second shape 1221: piezoelectric region 1222: non-piezoelectric region 1341: first discrete electrode unit 1342: second discrete electrode unit 1343: third discrete electrode unit 1344: fourth discrete electrode unit 1361: first hollow region 1362: second hollow region

This specification will be further described in the form of exemplary embodiments, which will be described in detail by the accompanying drawings. These embodiments are not restrictive, and in these embodiments, the same number represents the same structure, wherein:

FIG. 1 is a block diagram of an exemplary acoustic device according to some embodiments of the present specification;

FIG. 2 is a schematic diagram of an exemplary acoustic device according to some embodiments of the present specification;

FIG. 3 is a schematic diagram of the structure of an exemplary piezoelectric element according to some embodiments of the present specification;

FIG. 4 is a schematic diagram of a partial structure of an exemplary piezoelectric element according to some embodiments of the present specification;

FIG. 5A is a schematic diagram of an exemplary first-stage electrode structure according to some embodiments of the present specification;

FIG. 5B is a schematic diagram of the curve slope of the outer contour of an exemplary portion of a first-order electrode according to some embodiments of the present specification;

FIG. 5C is a schematic diagram of an exemplary secondary electrode structure according to some embodiments of the present specification;

FIG. 5D is a schematic diagram showing the slope of the curve of the outer contour of an exemplary portion of a second-order electrode according to some embodiments of the present specification;

FIG. 6 is a comparative diagram of frequency response curves of exemplary piezoelectric elements according to some embodiments of the present specification;

[FIG. 7A] is a vibration mode diagram of the piezoelectric element at the second-order valley frequency when the electrode completely covers one surface of the piezoelectric element (i.e., the electrode and the piezoelectric element overlap);

FIG. 7B is a vibration mode diagram of a piezoelectric element using a first-order electrode at a second-order valley frequency according to some embodiments of the present specification;

FIG. 7C is a vibration mode diagram of a piezoelectric element using a second-order electrode at a second-order valley frequency according to some embodiments of the present specification;

FIG. 8A is a schematic diagram of the structure of electrodes and piezoelectric elements according to some embodiments of the present specification;

FIG. 8B is a schematic diagram of the structure of electrodes and piezoelectric elements according to some embodiments of the present specification;

FIG. 8C is a schematic diagram of the structure of electrodes and piezoelectric elements according to some embodiments of the present specification;

FIG. 8D is a schematic diagram of the exploded structure of electrodes and piezoelectric elements according to some embodiments of the present specification;

FIG. 9 is a schematic diagram of a frequency response curve of a piezoelectric element according to some embodiments of the present specification;

FIG. 10 is a schematic structural diagram of a piezoelectric element of an exemplary additional mass block model according to some embodiments of the present specification;

FIG. 11A is a schematic diagram of an exemplary first-stage electrode according to some embodiments of the present specification;

FIG. 11B is a schematic diagram of an exemplary secondary electrode according to some embodiments of the present specification;

FIG. 12 is a comparative diagram of frequency response curves of exemplary piezoelectric elements according to some embodiments of the present specification;

FIG. 13A is a vibration mode diagram of a piezoelectric element at a second-order valley frequency when the electrode completely covers one surface of the piezoelectric element (i.e., the electrode and the piezoelectric element overlap) according to the added mass block model shown in some embodiments of the present specification;

FIG. 13B is a vibration mode diagram of a piezoelectric element with a first-order electrode designed under an additional mass block model according to some embodiments of the present specification at a second-order valley frequency;

FIG. 13C is a vibration mode diagram of a piezoelectric element with a second-order electrode designed in a model without an attached mass block according to some embodiments of the present specification at a second-order valley frequency;

FIG. 13D is a vibration mode diagram of a piezoelectric element with a second-order electrode designed using an added mass block model at a second-order valley frequency according to some embodiments of this specification;

FIG. 14A is a schematic diagram of a partial structure of an exemplary two-dimensional electrode according to some embodiments of the present specification;

FIG. 14B is a schematic diagram of a partial structure of an exemplary two-dimensional electrode according to some embodiments of the present specification;

FIG. 14C is a schematic diagram of a partial structure of an exemplary two-dimensional electrode according to some embodiments of the present specification;

FIG. 14D is a schematic diagram of a partial structure of an exemplary two-dimensional electrode according to some embodiments of the present specification;

FIG. 15A is a comparative diagram of frequency response curves of exemplary piezoelectric elements according to some embodiments of the present specification;

FIG. 15B is a comparative diagram of frequency response curves of exemplary piezoelectric elements according to some embodiments of the present specification;

FIG. 15C is a schematic diagram of the vibration displacement of the piezoelectric component covering the whole electrode at 5380.3 Hz according to some embodiments of the present specification;

FIG. 15D is a schematic diagram of the vibration displacement of a piezoelectric element covering an 8×8 discrete electrode unit at 5380.3 Hz according to some embodiments of the present specification;

FIG. 16A is a first-order modal vibration shape diagram of a piezoelectric component when the upper electrode of the rectangular piezoelectric component is completely covered (i.e., the entire electrode) according to some embodiments of the present specification;

FIG. 16B is a vibration mode diagram of a piezoelectric component at a high frequency when the upper electrode of the rectangular piezoelectric component is completely covered (i.e., the entire electrode) according to some embodiments of the present specification;

FIG. 16C is a vibration mode diagram at high frequency of a piezoelectric element using 16×8 discrete electrode units of two-dimensional electrodes on a rectangular piezoelectric element according to some embodiments of the present specification;

FIG. 16D is a vibration mode diagram at high frequency of a piezoelectric element using 32×16 discrete electrode units of two-dimensional electrodes on a rectangular piezoelectric element according to some embodiments of the present specification;

FIG. 17A is a schematic diagram of the design concept of a discrete electrode unit of an exemplary two-dimensional electrode according to some embodiments of this specification;

FIG. 17B is a schematic diagram of a discrete electrode unit of an exemplary two-dimensional electrode according to some embodiments of the present specification;

FIG. 17C is a schematic diagram of the shape of a first-order electrode corresponding to a rectangle equivalent to a fixed support beam at both ends shown in some embodiments of this specification;

FIG. 18 is a mode shape diagram of a piezoelectric component covering the two-dimensional electrode shown in FIG. 17B according to some embodiments of the present specification;

FIG. 19A is a schematic diagram of a partial structure of an exemplary two-dimensionally distributed continuous electrode according to some embodiments of the present specification;

FIG. 19B is a schematic diagram of a partial structure of an exemplary two-dimensionally distributed continuous electrode according to some embodiments of the present specification;

FIG. 19C is a schematic diagram of a partial structure of an exemplary two-dimensionally distributed continuous electrode according to some embodiments of the present specification;

FIG. 20 is a comparative diagram of frequency response curves of exemplary piezoelectric elements according to some embodiments of the present specification;

FIG. 21 is a schematic diagram of an exemplary acoustic device according to some embodiments of the present specification;

FIG. 22 is a comparative diagram of frequency response curves of exemplary piezoelectric elements according to some embodiments of the present specification;

FIG. 23A is a mode shape diagram of an acoustic device using an integral electrode according to some embodiments of the present specification;

FIG. 23B is a mode shape diagram of an acoustic device using a first-order electrode according to some embodiments of the present specification; and

[Figure 24] is a schematic diagram of the structure of an exemplary acoustic device shown in some embodiments of the present specification.

Among them, 100, acoustic device; 110, vibration component; 120, piezoelectric component; 130, electrode; 130-1, first-order electrode; 130-2, second-order electrode; 123, vibration output area; 121, substrate; 122, piezoelectric layer; 124, fixed area; 131, first electrode envelope area; 132, second electrode envelope area; 133, point; 1221, piezoelectric area; 1222, non-piezoelectric area; 140, mass Mass block model; 141, second vibration output region; 134, discrete electrode unit; 1341, first discrete electrode unit; 1342, second discrete electrode unit; 1343, third discrete electrode unit; 1344, fourth discrete electrode unit; 171, connector; 172, second shape; 135, continuous electrode; 136, hollow region; 1361, first hollow region; 1362, second hollow region; 170, mass block.

100:Acoustic equipment

110: Vibration component

120: Piezoelectric components

121: Substrate

122: Piezoelectric layer

130: Electrode

Claims (10)

An acoustic device includes: a piezoelectric element, the piezoelectric element generates vibration under the action of a driving voltage; an electrode, the electrode provides the driving voltage for the piezoelectric element; and a vibration element, the vibration element is physically connected to the piezoelectric element, receives the vibration and generates sound, wherein the piezoelectric element includes: a substrate; and a piezoelectric layer, the piezoelectric layer covers one surface of the substrate, The electrode is covered on a surface of the piezoelectric layer, and the covering area of the electrode on the surface of the piezoelectric layer is smaller than the surface area of the substrate covered with the piezoelectric layer; the piezoelectric layer includes a piezoelectric region and a non-piezoelectric region, the substrate, the piezoelectric layer and the electrode overlap respectively, and the covering area of the piezoelectric region on the substrate is smaller than the covering area of the piezoelectric layer on the substrate. An acoustic device as claimed in claim 1, wherein the piezoelectric element includes a vibration output region. As in the acoustic device of claim 2, wherein the piezoelectric element further includes a fixed area. An acoustic device as claimed in claim 3, wherein the width of the electrode gradually decreases from the fixed area to the vibration output area. As in claim 3, the acoustic device, wherein the electrode includes two electrode envelope regions, and the electric potentials of the two electrode envelope regions are opposite. As in the acoustic device of claim 5, there is a transition point between the two electrode envelope regions, and the electrode width in the first electrode envelope region of the two electrode envelope regions gradually decreases from the fixed region to the transition point. As in claim 6, the electrode width in the second electrode envelope region of the two electrode envelope regions first increases and then decreases from the switching point to the vibration output region. An acoustic device as claimed in claim 4, wherein the width of the electrode in the fixed area is equal to the width of the fixed area. As in claim 4, the width of the electrode in the vibration output area is 0. An acoustic device as claimed in claim 1, wherein the piezoelectric layer comprises a piezoelectric plate or a piezoelectric film, and the electrode comprises a plurality of two-dimensionally distributed discrete electrode units.

Images