WO2022006816A1 - Mems压电扬声器 - Google Patents

Mems压电扬声器 Download PDF

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Publication number
WO2022006816A1
WO2022006816A1 PCT/CN2020/101094 CN2020101094W WO2022006816A1 WO 2022006816 A1 WO2022006816 A1 WO 2022006816A1 CN 2020101094 W CN2020101094 W CN 2020101094W WO 2022006816 A1 WO2022006816 A1 WO 2022006816A1
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WIPO (PCT)
Prior art keywords
load plate
actuator
branch
shaped
arc
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PCT/CN2020/101094
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English (en)
French (fr)
Inventor
张孟伦
庞慰
杜拉尼·A·A
Original Assignee
诺思(天津)微系统有限责任公司
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Priority to PCT/CN2020/101094 priority Critical patent/WO2022006816A1/zh
Publication of WO2022006816A1 publication Critical patent/WO2022006816A1/zh

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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R19/00—Electrostatic transducers
    • H04R19/02—Loudspeakers

Definitions

  • the invention relates to a MEMS piezoelectric speaker.
  • FIG. 1 is a schematic diagram of an energy conversion structure of a MEMS speaker according to the prior art, which shows four microelectromechanical system MEMS actuators 12 arranged in a frame 11 (usually made of silicon material) branches, and a load tray 13 connected to one end of the four branches.
  • the actuator 12 realizes the coupling of sound energy and electric energy
  • the load plate 13 is used to conduct the vibration of the actuator to push the air to generate sound pressure or transmit the vibration energy of the actuator to the diaphragm layer of the speaker to push the air to generate sound pressure.
  • the miniaturization/miniaturization of speakers is one of the concerns in the industry. Due to the small size, the improvement of speaker performance (such as output sound pressure) is restricted to a certain extent. How to optimize the internal structure of the loudspeaker in a small size/small space is a key factor affecting the performance of the miniature loudspeaker.
  • the present invention proposes a MEMS piezoelectric speaker, which can more effectively utilize the internal space of the speaker, make the load plate have a larger amplitude, and realize a higher output sound pressure of the speaker.
  • a MEMS piezoelectric speaker is provided.
  • the MEMS piezoelectric speaker of the present invention includes a load plate and an actuator, the load plate is polygonal, circular, or elliptical, and each branch of the actuator is strip-shaped and arranged along the extension direction of the edge of the load plate.
  • the load plate is polygonal, and the number of branches of the actuator is consistent with the number of sides of the load plate; a connection portion is provided between one end of each branch of the actuator and the load plate.
  • the connecting portion there is a hollow slit in the connecting portion, and the slit communicates with the gap between the actuator and the load plate.
  • the end of the slit located inside the connecting portion has a rounded chamfer.
  • the load plate is rectangular; the actuator has 2 branch groups and is arranged on a set of opposite sides of the load plate, or the actuator has 4 branch groups and is arranged on each side of the load plate; the branch group has a A branch and a B branch, wherein both ends of the A branch are connected with the frame of the speaker, a connection part is formed between the middle part of the A branch and the middle part of the B branch, and a connection part is formed between the two ends of the B branch and the load plate.
  • the load plate is circular or oval; the actuator has at least two arc-shaped branches; each arc-shaped branch and the load plate and between the frame of the speaker have connection parts respectively.
  • the actuator has at least 2 arc-shaped branches, each arc-shaped branch has 2 arc-shaped segments, and both ends of the first arc-shaped segment are respectively connected to both ends of the second arc-shaped segment; the arc-shaped branch is connected to the speaker.
  • the connection part between the frames is located in the middle of the first arc-shaped segment; the connection part between the arc-shaped branch and the load plate is located in the middle of the second arc-shaped segment.
  • the actuator has at least 4 arc-shaped branches and forms at least two layers of surrounding circles surrounding the load plate; each arc-shaped branch has 2 arc-shaped segments, and two ends of the first arc-shaped segment are respectively connected to two arc-shaped segments.
  • another MEMS piezoelectric speaker is provided.
  • the MEMS piezoelectric speaker of the present invention includes a load plate and an actuator, the load plate is rectangular or circular; the actuator has a rectangular frame branch, a first branch, and a second branch, wherein: the first branch and the second branch The two ends of the speaker are respectively connected with the frame of the speaker; the load plate is located in the rectangular frame-shaped branch, and the middle parts of the first group of opposite sides of the rectangular frame-shaped branch are respectively connected with the load plate; the first branch and the second branch Outside the rectangular frame-shaped branch, there are connecting parts between the middle parts of the second group of opposite sides of the rectangular frame-shaped branch and the middle parts of the first branch and the second branch respectively.
  • another MEMS piezoelectric speaker is provided.
  • the MEMS piezoelectric speaker of the present invention includes a load plate and an actuator, and the load plate is rectangular; the actuator has four branches with four arcuate turns, which are arranged two by two on a set of opposite sides of the load plate; The first end is connected to the frame of the speaker, and the second end is respectively connected to one vertex of the load plate; the branches located on the same side of the load plate are arranged axially symmetrically with respect to the vertical line of the side.
  • another MEMS piezoelectric speaker is provided.
  • the MEMS piezoelectric speaker of the present invention includes a load plate and an actuator, the load plate is a polygon, and the number of sides N is an even number; the actuator has N/2 L-shaped branches, surrounding the load plate, and the N vertices of the load plate Among them, one vertex is connected to the end point of the L-shaped branch at every interval of 1 vertex; the L-shaped branch has one or more layers from the inside to the outside from the load plate, and the first layers of each layer in the same branch are connected.
  • another MEMS piezoelectric speaker is provided.
  • the MEMS piezoelectric speaker of the present invention includes a load plate and an actuator, and the load plate is circular or oval; the actuator has two parallel bar-shaped branches located on both sides of the load plate; The end is connected with the frame of the speaker, the middle part is connected with the load plate, and the connecting lines of the two connection points pass through the center of the load plate.
  • another MEMS piezoelectric speaker is provided.
  • the MEMS piezoelectric speaker of the present invention includes a load plate and an actuator, the load plate is circular or elliptical; the actuator has at least 2 bar-shaped branches and at least 2 arc-shaped branches, and the arc-shaped branches form a surrounding circle and The load plate is surrounded, and the bar-shaped branches are located outside the surrounding circle; the two ends of each bar-shaped branch are connected with the frame of the speaker; the middle part of each bar-shaped branch and the arc-shaped branch have a connecting part; each arc-shaped branch is connected to the load There are connecting parts between the discs.
  • the actuator has 2 bar-shaped branches and 2 arc-shaped branches; the connection part between the arc-shaped branch and the load plate is located at the end of the arc-shaped branch.
  • another MEMS piezoelectric speaker is provided.
  • the MEMS piezoelectric speaker of the present invention includes a load plate and an actuator, wherein the load plate is circular or elliptical; the actuator coils the load plate, and the actuator is in a plane spiral shape or includes a plurality of plane spiral branches.
  • the load plate and the actuator are in the same plane.
  • the sum of the area of the actuator and the area of the load plate is greater than 80% of the area of the chip where the speaker is located.
  • the total length of all branches of the actuator is not less than the circumference of the load plate or the entire speaker chip.
  • the load plate and the actuator are in the same plane.
  • the space inside the speaker is effectively utilized, the actuator has a larger effective length, the vibration amplitude of the load plate is increased, and the output sound pressure of the speaker is increased.
  • FIG. 1 is a schematic diagram of an energy conversion structure of a MEMS speaker according to the prior art
  • FIG. 2A is an exploded exploded view of a loudspeaker structure according to an embodiment of the present invention.
  • FIG. 2B is a schematic diagram of the material layers of the actuator 12 in the structure of FIG. 2A;
  • 3A is a schematic diagram of the main components of an energy conversion structural layer according to an embodiment of the present invention.
  • FIG. 3B is a perspective view of a transient state of the structure shown in FIG. 3A during operation;
  • 3C is a schematic diagram of the structure of another actuator according to an embodiment of the present invention.
  • FIG. 4 is a schematic diagram of the main components of yet another energy conversion structural layer according to an embodiment of the present invention.
  • FIG. 5 is a schematic diagram of the main components of yet another energy conversion structural layer according to an embodiment of the present invention.
  • 6A is a schematic diagram of the structure of a load plate and an actuator according to an embodiment of the present invention.
  • FIG. 6B is a schematic diagram of the displacement of the structure shown in FIG. 6A during operation
  • FIG. 7A is a schematic diagram of another load plate and actuator structure according to an embodiment of the present invention.
  • FIG. 7B is a schematic diagram of the displacement of the structure shown in FIG. 7A during operation;
  • FIG. 8A is a schematic diagram of another load plate and actuator structure according to an embodiment of the present invention.
  • FIG. 8B is a schematic diagram of the displacement of the structure shown in FIG. 8A during operation
  • FIG. 9A is a schematic diagram of yet another load plate and actuator structure according to an embodiment of the present invention.
  • FIG. 9B is a schematic diagram of the displacement of the structure shown in FIG. 9A during operation;
  • 10A is a schematic diagram of another structure of a load plate and an actuator according to an embodiment of the present invention.
  • FIG. 10B is a schematic diagram of the displacement of the structure shown in FIG. 10A during operation;
  • 11A is a schematic diagram of another structure of a load plate and an actuator according to an embodiment of the present invention.
  • FIG. 11B is a schematic diagram of the displacement of the structure shown in FIG. 11A during operation;
  • FIG. 12A is a schematic diagram of another structure of a load plate and an actuator according to an embodiment of the present invention.
  • FIG. 12B is a schematic diagram of the displacement of the structure shown in FIG. 12A during operation;
  • Fig. 12C is a schematic diagram of another load plate and the displacement of the actuator during operation according to an embodiment of the present invention, wherein the actuator branch is 1 layer;
  • FIG. 12D is a schematic diagram of another load plate and the displacement of the actuator during operation according to an embodiment of the present invention, wherein the actuator branches into 2 layers;
  • FIG. 13A is a schematic diagram of a structure of yet another load plate and actuator according to an embodiment of the present invention.
  • FIG. 13B is a schematic diagram of the displacement of the structure shown in FIG. 13A during operation;
  • 14A is a schematic diagram of a structure of yet another load plate and actuator according to an embodiment of the present invention.
  • FIG. 14B is a schematic diagram of the displacement of the structure shown in FIG. 14A during operation;
  • 15A is a schematic diagram of yet another load plate and actuator structure according to an embodiment of the present invention.
  • FIG. 15B is a schematic diagram of the displacement of the structure shown in FIG. 15A during operation;
  • 16A and 16B are schematic diagrams of a helical actuator according to an embodiment of the present invention.
  • the load plate 13 is located on the extension line of the strip branch of the actuator 12. According to this layout, if the overall area of the speaker is constant, if the actuator branch needs to be guaranteed If the length of the load plate is increased, the area of the load plate will be affected. If the area of the load plate is to be increased, the length of the actuator branch should be shortened. Therefore, the layout cannot take into account the area of the load plate and the length of the actuator branch, which affects the output sound pressure of the speaker. On the other hand, the simple rectangular shape of the actuator results in lower equivalent bending compliance, which is reflected in the smaller maximum displacement of the actuator (that is, the limited displacement of the load plate), which ultimately affects the maximum output sound pressure of the loudspeaker.
  • the shape and arrangement of the actuator branches are changed compared with FIG. 1, so that the equivalent length and equivalent bending flexibility of the actuator are improved under the condition that the area occupied by the speaker is limited, Therefore, the maximum displacement of the actuator and the corresponding displacement of the load plate are increased, and finally the output sound pressure of the loudspeaker is increased.
  • FIG. 2A is an exploded view of a loudspeaker structure according to an embodiment of the present invention
  • FIG. 2B is a schematic diagram of material layers of the actuator structure 12 in FIG. 2A .
  • the energy conversion structure layer of the speaker which specifically includes the following components 11 to 15.
  • the frame which supports the actuator and realizes the electrical interconnection of the actuator.
  • Actuator the coupling and mutual conversion of electric energy and acoustic energy in the speaker occurs in this part, specifically, the actuator can convert the electric energy input into it into mechanical vibration (sound energy).
  • Load plate The structure itself does not perform the coupling and mutual conversion of electric energy and sound energy, but passively accepts the vibration energy generated by the actuator, and conducts the energy of the actuator to the vibrating membrane layer.
  • First connecting part This part is used to connect the load plate 13 and the actuator 12 .
  • Second connecting part This part is used to connect the frame 11 and the actuator 12 .
  • the energy conduction block of the speaker This structure is used to conduct vibration energy. According to the specific structure design, this part can sometimes be omitted.
  • the lower limit layer including the lower peripheral portion 31 and the annular protrusion 32 inwardly.
  • Energy exchange interface layer which specifically includes:
  • a periphery with an annular arched structure specifically including: an annular overlapping portion 44 with the lower peripheral portion 31, and an elastic portion 43 with an annular arched portion.
  • a vibrating membrane layer which acts as an interface between the loudspeaker and the external sound medium (usually air) to exchange sound energy. Specifically, the membrane layer transmits the sound wave energy into the air through vibration.
  • Upper limit layer comprising the upper peripheral portion 51 and the annular protrusion 52 inwardly
  • PCB board It includes the main body of the PCB and the electrical links or chips such as ASICs distributed in it.
  • the basic working process of the above-mentioned loudspeaker is as follows: first, the control signal is conducted from the outside to the loudspeaker PCB board 60, and is received and processed by the signal conversion/processing chip 62 therein.
  • the electrical contacts between 60 and the frame 11 enter the actuator 12 and are converted into mechanical vibrations in the actuator 12 .
  • the vibration energy of the actuator 12 will be transmitted to the load plate 13 through the first connection part 14, and then transmitted to the diaphragm layer 42 through the energy conduction block 20 or directly from the load plate 13, and the vibration energy of the diaphragm layer 42 will finally enter the external medium of the speaker. , such as air.
  • FIG. 5 a structure shown in FIG. 5 is also shown in FIG. 2B and further explained below.
  • the embodiment of the present invention provides the energy conversion structure layer 10 of the loudspeaker in various other optional manners, and the load plate and the actuator may be located on the same plane. The following description is given in conjunction with the accompanying drawings.
  • the load plate is polygonal, circular, or elliptical, and each branch of the actuator is strip-shaped and arranged along the extending direction of the edge of the load plate. Because the parts of the actuator are usually moved synchronously, in the description of this paper, the parts that are not directly connected are regarded as belonging to the same actuator, and considered as a branch of the actuator.
  • Various specific ways of a type of loudspeaker energy conversion structure layer in the embodiments of the present invention, especially the structures of the load plate and the actuator, will be described respectively below.
  • FIG. 2B is a schematic diagram of material layers of the actuator structure 12 in FIG. 2A .
  • the actuator 12a includes a four-layer structure, which are a bias layer 12-1, a lower electrode 12-2, a piezoelectric layer 12-3, and an upper electrode 12-4, respectively.
  • the bias layer is used to bias the longitudinal neutral axis of the overall actuator, so that the in-plane stress of the piezoelectric layer generates out-of-plane displacement of the actuator, and at the same time plays a supporting role for the actuator's thin-film structure.
  • Materials can be selected from single crystal silicon, silicon dioxide, aluminum nitride, molybdenum, aluminum, gold and other metals.
  • the material of the lower electrode of the actuator can be selected from molybdenum, platinum, aluminum, gold, tungsten, ruthenium and so on.
  • the upper electrode material of the actuator can be selected from molybdenum, platinum, aluminum, gold, tungsten, ruthenium, etc.
  • the piezoelectric layer can be made of aluminum nitride, zinc oxide, and rare earth element doped materials of the above materials (such as scandium doping with a certain atomic ratio), or lead zirconate titanate, doped lead zirconate titanate, and lithium niobate. , lithium tantalate, polyvinylidene fluoride (pvdf), etc.
  • the actuator is a thin film structure in the thickness direction, that is, the longitudinal thickness is generally not more than 100 microns. Since the actuator is a thin-film structure, its longitudinal flexural modulus is small, so it can output a large sound pressure. Electrodes and piezoelectric layers are generally obtained by a thin-film fabrication process.
  • FIG. 3A is a schematic diagram of the main components of an energy conversion structural layer according to an embodiment of the present invention.
  • the load plate 13 has a rectangular or square structure, and there are four rectangular connecting parts 14 on the edge of the load plate 13 close to the vertex, the long sides of the four rectangular actuators 12 and the four rectangular load plates 13 .
  • the edges are kept substantially parallel, and each actuator 12 is connected with the central load plate 13 through a connecting portion 14, wherein the link portion 14 is connected to the load plate 13 on one side, and the other side is connected to one end of the actuator 12, and the actuator The other end of 12 is connected to the inner edge of frame 11 .
  • This arrangement can make the structure formed by the actuator 12 and the load plate 13 as compact as possible on the premise of ensuring that the actuator 12 generates sufficient amplitude, thereby reducing the space occupied.
  • Fig. 3B is a perspective view of the structure shown in Fig. 3A in a transient state during operation.
  • the central load plate is displaced in the positive direction of the Z-axis, and the surrounding actuators are upward about their fixed points on the inner edge of the frame. A slight wobble occurs.
  • the load plate and the actuator shown in the figure can also form a displacement state opposite to that shown in the figure.
  • the surrounding actuators that move the load plate along the Z-axis.
  • the Z-direction movement of the central load plate and its surrounding actuators is also accompanied by a small expansion/swing of the actuator in the horizontal direction and a small rotation of the load plate in the horizontal plane, and these movements are associated, if The amplitude of one of the motion modes is limited, and the amplitude of the other modes of motion is also limited.
  • the load plate 13 and the actuator 12 can have a larger vibration amplitude in the Z direction, it is necessary to reduce the restriction on the central load plate and the actuator in the horizontal direction.
  • the above constraints mainly come from the connection between the load plate 13 and the actuator 12 and the connection between the actuator and the inner edge of the frame 11 . Therefore, an improved structure that can increase the freedom of horizontal movement of the load plate and the actuator is provided in the embodiment of the present invention, as shown in FIG. 3C , which is a schematic diagram of the structure of another actuator according to the embodiment of the present invention.
  • FIG. 3C there is a curved hollow slit in the connecting portion 14 , and the slit can improve the mechanical flexibility of the connecting portion.
  • the slit communicates with the gap between the actuator 12 and the load plate 13 and has a rounded chamfer at the end of the shown slit inside the connecting portion 14, which prevents stress build-up from forming at the end of the slit crack.
  • the improved structure in FIG. 3C facilitates greater horizontal movement of the actuator 12 and load plate 13, thereby increasing the range of movement of 12 and 13 in the Z direction.
  • the structure of the load plate can be other polygons, for example, as shown in FIG. 4 , which is a schematic diagram of the main components of another energy conversion structure layer according to an embodiment of the present invention, wherein the load plate 13 has a regular hexagonal structure , there are 6 right-angled trapezoidal connecting parts 14 on the edge of the load plate 13 close to the vertex, wherein the inclined waist of the trapezoidal connecting part is in the direction of the extension of the adjacent side of the hexagonal side where the connecting part is located, and 6 rectangular actuators
  • the long sides of 12 are basically parallel to the six edges of the regular hexagonal load plate 13, and each actuator 12 is connected with the central load plate 13 through a connecting portion 14, wherein one side of the connecting portion 14 (the long bottom of the trapezoid) is connected.
  • FIG. 5 is a schematic diagram of the main components of another energy conversion structure layer according to an embodiment of the present invention, wherein the central load plate 13 is circular, and the four connecting parts 14 are evenly arranged on the circumference
  • the four connecting parts 15 are evenly arranged on the circular inner edge of the frame 11
  • the circular load plate 13 is concentric with the circular inner edge of the frame 11 .
  • a partially annular actuator 12 branch is connected between each pair of connecting parts ( 14 and 15 ), and the inner and outer edges of each branch are concentric with the circular load plate 13 .
  • the number of branches of the actuator 12 shown in FIG. 5 and the number of the corresponding connection parts 14 and 15 are not limited to 4, but can be changed according to the actual situation.
  • the structure shown in 4A 3, 5 , 6 actuators and so on. The more the number of actuators, the more stable and reliable the vibration.
  • the branches of the actuator can also have a more complex shape, including a plurality of arc-shaped branches that constitute an inner-to-outward layer or several surrounding the load plate.
  • FIG. 6A is a schematic diagram of the structure of a load plate and an actuator according to an embodiment of the present invention.
  • the load plate 1 is circular and has two turns of actuator branches 6 on the outside thereof.
  • the actuator branches 6 can be further divided into two groups, the upper and lower groups, each group is a semi-circular arc as a whole, and each group contains two semi-circular arc branches correspondingly connected at both ends to form two layers from the inside to the outside from the load plate 1 .
  • the connecting portion in FIG. 6A as well as the connecting portions in other figures herein, have relatively small areas, so as to form as flexible a connection as possible between the connected parts and improve the degree of freedom of movement.
  • FIG. 6B is a schematic diagram of the displacement of the structure shown in FIG. 6A during operation.
  • the actuator and the load plate 1 vibrate up and down. The darker the color, the greater the upward displacement.
  • the meaning of the colors in the other schematic diagrams representing the displacement during operation is the same. It can be seen that at the connection part 4 between the actuator and the frame, the displacement is the smallest, and the displacement of each part of the actuator branch gradually increases along the direction of the branch extending to the load plate, so that the actuator branch has a longer equivalent length In the case of vibration, the load plate will have a correspondingly larger displacement during vibration.
  • FIG. 7A is a schematic diagram of another structure of a load plate and an actuator according to an embodiment of the present invention.
  • the actuator branches 7 are divided into four groups, and each group is a quarter-circle arc as a whole, and each group includes two semi-circular arc branches whose ends are connected correspondingly, so as to form a starting point from the load plate 1 .
  • FIG. 7B is a schematic diagram of the displacement of the structure shown in FIG. 7A during operation. Similar to FIG. 6B , the displacement of the connecting portion 4 of the actuator and the frame is the smallest, and the displacement of the load plate is the largest.
  • FIG. 8A is a schematic diagram of the structure of another load plate and actuator according to an embodiment of the present invention.
  • the actuator branches 8 are divided into four groups, each group is a semi-circular arc as a whole, and each group includes two semi-circular arc branches whose ends are correspondingly connected to form the load plate 1 from the inside to the outside the fourth floor.
  • FIG. 8B is a schematic diagram of the displacement of the structure shown in FIG. 8A during operation. Similar to FIG. 8B , the displacement of the connecting portion 4 of the actuator and the frame is the smallest, and the displacement of the load plate is the largest.
  • FIG. 9A is a schematic diagram of yet another structure of a load plate and an actuator according to an embodiment of the present invention, wherein a set of load plates 1 On the outside of the opposite side, there are two-layer actuator strip branches from the inside to the outside. There is a connecting part 4 between the inner strip branch and the load plate, and a connecting part 3 between the outer strip branch and the outer strip. The two ends 5 of the strip-shaped branches of the layer are connected to the frame of the energy conversion structure layer (ie the frame 11 above, not shown in the figures).
  • FIG. 9B is a schematic diagram of the displacement of the structure shown in FIG. 9A during operation. It can be seen from the figure that the displacement of the entire structure increases gradually from the position where the actuator branch is connected to the frame to the load plate.
  • FIG. 9A can be regarded as a bar-shaped branch in which a group of actuators are arranged on a group of opposite sides of the load plate, and each group has two branches.
  • a group of strip-shaped branches of the actuators may be arranged on the four sides of the load plate, as shown in FIG. 10A , which is a schematic diagram of another structure of the load plate and the actuator according to an embodiment of the present invention
  • FIG. 10B is a schematic diagram of the structure of the actuator.
  • both ends of the inner bar-shaped branch are connected to the apex of the load plate 1 , the middle and the peripheral bar-shaped branch are connected via the connecting portion 7 , and the two ends 5 of the peripheral bar-shaped branch are connected to the frame.
  • FIG. 11A is a schematic diagram of another structure of a load plate and an actuator according to an embodiment of the present invention
  • FIG. 11B is a schematic diagram of the displacement of the structure shown in FIG. 11A during operation.
  • the four branches 8 of the actuator are bent in an arcuate shape, and are symmetrical from left to right and up and down according to the viewing angle in the figure, so that the entire load plate is uniformly stressed.
  • One end of each branch of the actuator is connected to the apex of the load plate, and the other end 5 is connected to the frame.
  • the load plate can be a polygon (the polygon here includes a quadrilateral), and the number of sides is even.
  • its periphery can be along the direction of the sides of the load plate, surrounding one or more layers of L-shaped actuator branches, Because it is to be parallel to the side of the load plate, the L shape here can be a right angle or an obtuse angle, and the angle depends on the number of sides of the load plate. Two examples are given below for description.
  • FIG. 12A is a schematic diagram of another structure of a load plate and an actuator according to an embodiment of the present invention
  • FIG. 12B is a schematic diagram of the displacement of the structure shown in FIG. 12A during operation.
  • the two sets of branches of the actuator 9 are L-shaped and are arranged along the diagonal direction of the load plate 1 , and each L-shaped branch also includes two L-shaped segments, which constitutes an inward direction from the load plate 1 .
  • the outer two-layer actuator branches one end of the inner layer L-shaped segment is connected to a vertex of the load plate 1, and the other end is connected to one end of the outer layer L-shaped segment. It can be seen from Fig. 12B that the force-bearing point of the load plate is the end point of a diagonal line, and the force is uniform.
  • FIG. 12A shows the case where the actuator branches are in two layers, but may be in one layer.
  • Fig. 12C is a schematic diagram of displacement of another load plate and actuator during operation according to an embodiment of the present invention, wherein the actuator branch is 1 layer;
  • Fig. 12D is another kind of load plate and actuator according to an embodiment of the present invention. Schematic diagram of the displacement at work, where the actuator branches into 2 layers.
  • the use of more layers of the actuator helps to increase the vertical displacement of the load plate to meet the index requirements, which can be seen by comparing Figure 12C and Figure 12D (the displacement of 12D is twice the displacement of 12C) .
  • more load plate sides or more actuator branches can reduce or eliminate load plate tilt in vertical vibration, minimize airflow leakage, improve sound pressure, and help The stability of the motion of the load pan is ensured, which is shown here as the motion stability and sound pressure of Figures 12C and 12D are greater than those of Figures 12A and 12B.
  • the number of branches of the actuator that is, the number of connecting parts between the actuator and the load plate
  • the number of branches of the actuator can be greater than the number of sides of the load plate.
  • FIG. 13A is a schematic diagram of another structure of a load plate and an actuator according to an embodiment of the present invention, wherein the load plate 1 can be rectangular or square, the frame-shaped branch of the actuator surrounds the load plate 1, and there is a connecting part between the two , the actuator also has 2 bar-shaped branches, which respectively have connecting parts 6 with a set of opposite sides of the frame-shaped branches, and both ends 5 of the bar-shaped branches are connected to the frame of the energy conversion structure layer (ie the frame 11 above, Fig. not shown).
  • FIG. 13B is a schematic diagram of the displacement of the structure shown in FIG. 13A during operation. It can be seen from the figure that the displacement of the entire structure increases gradually from the position where the actuator branch is connected to the frame to the load plate.
  • FIG. 14A is a schematic diagram of another structure of a load plate and an actuator according to an embodiment of the present invention
  • FIG. 14B is a schematic diagram of the displacement of the structure shown in FIG. 14A during operation.
  • the load plate 1 is circular, with a branch of the actuator 2 at the upper and lower sides, and a connecting portion 3 therebetween.
  • the end 4 of the branch of the actuator 2 is used to connect to the frame.
  • the branches of the actuator may also include both bar-shaped branches and arc-shaped branches.
  • FIG. 15A is a schematic diagram of another structure of a load plate and an actuator according to an embodiment of the present invention
  • FIG. 15A is a schematic diagram of another structure of a load plate and an actuator according to an embodiment of the present invention
  • FIG. 15A is a schematic diagram of another structure of a load plate and an actuator according to an embodiment of the present invention
  • FIG. 15B is a schematic diagram of the displacement of the structure shown in FIG. 15A during operation.
  • there is also a semi-circular arc-shaped actuator branch 5 between the branch of the actuator and the load plate 1 in FIG. 15A there is a connecting part between the middle part and the bar-shaped branch, and the two ends are respectively connected to the load plate 1 . There are connections.
  • FIG. 15A it can be seen that in FIG. 6A , FIG. 7A , and FIG. 8A , a similar method can also be used, that is, the connecting portion 4 is connected to the strip-shaped branch of the actuator, and the two ends of the strip-shaped branch are connected to the frame. .
  • the actuator and load plate may also have other forms, such as those shown in Figures 16A and 16B.
  • 16A and 16B are schematic diagrams of a helical actuator according to an embodiment of the present invention.
  • the load plate 13 is circular, and the actuator 12 is connected to the edge of the load plate and spirally wound outward from the center. In this way, space utilization is improved, and the equivalent length of the actuator is longer, which helps to increase the vibration amplitude of the load plate.
  • the actuator 12 has two branches, both of which are connected to the edge of the load plate 13 and spiral out from the center. In this way, the structure composed of the actuator and the load plate is more stable.
  • the branches of the actuator are located on the side of the load plate, the branches of the actuator can be arranged along the extension direction of the edge of the load plate, and the branches can also adopt a roundabout shape, which helps Better utilization of the space of the speaker's energy conversion layer allows the actuator to have a larger effective length and higher equivalent bending compliance, increasing the amplitude of the load disk.
  • the shape of the load plate is not limited to polygonal, circular, or elliptical.
  • the sum of the two can be greater than 80% of the area of the chip where the speaker is located, which helps to ensure the effective length of the actuator and the area of the load plate, and improves the output sound pressure of the speaker.
  • the total length of all branches of the actuator may not be less than the perimeter of the load plate or the entire speaker chip, ensuring the length of the actuator helps to improve the output sound pressure of the speaker.

Abstract

本发明提供了一种MEMS压电扬声器，包括负载盘和执行器，负载盘为多边形、圆形、或椭圆形，执行器的各分支为条形并且沿着负载盘的边缘的延伸方向设置。根据本发明的技术方案，有效利用了扬声器内部的空间，使执行器有较大的有效长度，提高负载盘的振动幅度，增大了扬声器的输出声压。

Description

MEMS压电扬声器 技术领域
本发明涉及一种MEMS压电扬声器。
背景技术
微型扬声器目前被广泛的应用于各类小型化微型化的声学器件、电子设备，用于多媒体及电子娱乐设备之中。而MEMS执行器是上述扬声器的重要组成部分，其核心工作原理是利用压电材料实现声能(机械能)-电能的耦合和相互转化。如图1所示，图1是根据现有技术中的MEMS扬声器的能量转化结构的示意图，其中示出了框架11(通常采用硅材料制造)内设置的微机电系统MEMS执行器12的四个分支，以及连接于该四个分支一端的负载盘13。执行器12实现声能和电能的耦合，负载盘13用来传导执行器的振动以推动空气产生声压或将执行器的振动能量传导至扬声器的振动膜层来推动空气产生声压。
目前，扬声器的小型/微型化是业内的关注点之一。由于尺寸小，扬声器的性能(如输出声压)提升受到一定的制约。如何在小尺寸/小空间下进行扬声器的内部结构优化设计是影响微型扬声器性能的关键要素。
发明内容
有鉴于此，本发明提出一种MEMS压电扬声器，能够更有效的利用扬声器内部空间，使负载盘有更大的振幅，实现扬声器更高的输出声压。
为实现上述目的，根据本发明的一个方面，提供了一种MEMS压电扬声器。
本发明的这种MEMS压电扬声器，包括负载盘和执行器，负载盘为多边形、圆形、或椭圆形，执行器的各分支为条形并且沿着负载盘的边缘 的延伸方向设置。
可选地，负载盘为多边形，执行器的分支数目与负载盘的边的数目一致；执行器的各分支的一端与负载盘之间具有连接部。
可选地，所述连接部中存在一条镂空狭缝，该狭缝与执行器和负载盘之间的间隙相连通。
可选地，所述狭缝位于连接部内部的末端具有圆形倒角。
可选地，负载盘为矩形；执行器具有2个分支组并且设置在负载盘的一组对边，或者执行器具有4个分支组并且设置在负载盘的各边；所述分支组具有甲分支和乙分支，其中，甲分支的两端与所述扬声器的框架连接，甲分支的中部与乙分支的中部之间有连接部，乙分支的两端与负载盘之间有连接部。
可选地，负载盘为圆形或椭圆形；执行器具有至少2个弧形分支；各弧形分支与负载盘之间、与所述扬声器的框架之间，分别具有连接部。
可选地，执行器具有至少2个弧形分支，各弧形分支具有2个弧形段，第一弧形段两端分别连接第二弧形段两端；弧形分支与所述扬声器的框架之间的连接部位于第一弧形段中部；弧形分支与负载盘之间的连接部位于第二弧形段中部。
可选地，执行器具有至少4个弧形分支并且形成包围负载盘的至少两层包围圈；各弧形分支具有2个弧形段，第一弧形段两端分别连接第二弧形段两端；最内层的包围圈的第一弧形段的中部与负载盘之间具有连接部；相邻包围圈之间具有连接部；最外层包围圈的第二弧形段的中部与所述扬声器的框架之间具有连接部。
根据本发明的另一方面，提供了另一种MEMS压电扬声器。
本发明的这种MEMS压电扬声器，包括负载盘和执行器，负载盘为矩形或圆形；执行器具有矩形框状分支、第一分支、第二分支，其中：第一分支和第二分支的两端分别与所述扬声器的框架连接；负载盘位于矩形框状分支内，矩形框状分支的第一组对边的中部分别与负载盘之间有连接部；第一分支和第二分支位于矩形框状分支外，矩形框状分支的第二组对边的中部分别与第一分支和第二分支的中部之间有连接部。
根据本发明的另一方面，提供了另一种MEMS压电扬声器。
本发明的这种MEMS压电扬声器，包括负载盘和执行器，负载盘为矩形；执行器具有4个弓字形转折的4个分支，两两设置在负载盘的一组对边；各分支的第一端与所述扬声器的框架连接，第二端分别与负载盘的一个顶点连接；位于负载盘同一边的分支关于该边的中垂线呈轴对称设置。
根据本发明的另一方面，提供了另一种MEMS压电扬声器。
本发明的这种MEMS压电扬声器，包括负载盘和执行器，负载盘为多边形，边数N为偶数；执行器具有N/2个L形分支，包围负载盘四周，负载盘的N个顶点中，每间隔1个顶点即有1个顶点与L形分支的端点连接；所述L形分支自负载盘起由内至外具有一层或多层，同一分支内的各层首层连接。
根据本发明的另一方面，提供了另一种MEMS压电扬声器。
本发明的这种MEMS压电扬声器，包括负载盘和执行器，负载盘为圆形或椭圆形；执行器具有2个互相平行的条形分支，位于负载盘两侧；各条形分支的两端与所述扬声器的框架连接，中部与负载盘连接并且两个连接处的连线经过负载盘的圆心。
根据本发明的另一方面，提供了另一种MEMS压电扬声器。
本发明的这种MEMS压电扬声器，包括负载盘和执行器，负载盘为圆形或椭圆形；执行器具有至少2个条形分支，以及至少2个弧形分支，弧形分支形成包围圈并且包围负载盘，条形分支位于该包围圈之外；各条形分支的两端与所述扬声器的框架连接；各条形分支的中部与弧形分支之间具有连接部；各弧形分支与负载盘之间具有连接部。
可选地，执行器具有2个条形分支和2个弧形分支；弧形分支与负载盘之间的连接部位于弧形分支的端部。
根据本发明的另一方面，提供了另一种MEMS压电扬声器。
本发明的这种MEMS压电扬声器，包括负载盘和执行器，负载盘为圆形或椭圆形；执行器盘绕负载盘，执行器为平面螺旋形或包含多个平面螺旋形分支。
可选地，负载盘和执行器位于同一平面。
可选地，执行器面积与负载盘的面积之和大于所述扬声器所在芯片面积的80％。
可选地，执行器的所有分支的总长度不小于负载盘或整个扬声器芯片的周长。
可选地，负载盘和执行器位于同一平面。
根据本发明的技术方案，有效利用了扬声器内部的空间，使执行器有较大的有效长度，提高负载盘的振动幅度，增大了扬声器的输出声压。
附图说明
为了说明而非限制的目的，现在将根据本发明的优选实施例、特别是参考附图来描述本发明，其中：
图1是根据现有技术中的MEMS扬声器的能量转化结构的示意图；
图2A是根据本发明实施方式的一种扬声器结构的爆炸展开图；
图2B是图2A结构中执行器12的材料层示意图；
图3A是根据本发明实施方式的一种能量转换结构层的主要部件的示意图；
图3B是图3A所示结构在工作时的一个瞬时状态的立体视图；
图3C是根据本发明实施方式的又一种执行器的结构的示意图；
图4是根据本发明实施方式的又一种能量转换结构层的主要部件的示意图；
图5是根据本发明实施方式的又一种能量转换结构层的主要部件的示意图；
图6A是根据本发明实施方式的一种负载盘和执行器的结构的示意图；
图6B是图6A所示结构在工作时的位移的示意图；
图7A是根据本发明实施方式的另一种负载盘和执行器结构的示意图；
图7B是图7A所示结构在工作时的位移的示意图；
图8A是根据本发明实施方式的另一种负载盘和执行器结构的示意图；
图8B是图8A所示结构在工作时的位移的示意图；
图9A是根据本发明实施方式的又一种负载盘和执行器结构的示意图；
图9B是图9A所示结构在工作时的位移的示意图；
图10A是根据本发明实施方式的又一种负载盘和执行器的结构的示意图；
图10B是图10A所示结构在工作时的位移的示意图；
图11A是根据本发明实施方式的又一种负载盘和执行器的结构的示意图；
图11B是图11A所示结构在工作时的位移的示意图；
图12A是根据本发明实施方式的又一种负载盘和执行器的结构的示意图；
图12B是图12A所示结构在工作时的位移的示意图；
图12C是根据本发明实施方式的又一种负载盘和执行器在工作时的位移的示意图，其中执行器分支为1层；
图12D是根据本发明实施方式的又一种负载盘和执行器在工作时的位移的示意图，其中执行器分支为2层；
图13A是根据本发明实施方式的又一种负载盘和执行器的结构的示意图；
图13B是图13A所示结构在工作时的位移的示意图；
图14A是根据本发明实施方式的又一种负载盘和执行器的结构的示意图；
图14B是图14A所示结构在工作时的位移的示意图；
图15A是根据本发明实施方式的又一种负载盘和执行器结构的示意图；
图15B是图15A所示结构在工作时的位移的示意图；
图16A和图16B是根据本发明实施方式的螺旋形执行器的示意图。
具体实施方式
图1所示的现有技术中的MEMS扬声器，其负载盘13位于执行器12的条形分支的延长线上，按照这种布局，在扬声器整体面积一定的情况下，如要保证执行器分支的长度，则负载盘面积受到影响，如要增大负载盘面积，则需缩短执行器分支长度。因此该布局无法兼顾负载盘面积和执行器分支长度，影响了扬声器的输出声压。另一方面，执行器的简单矩形形状导致其等效弯曲柔度较低，体现为执行器的最大位移较小(也即负载盘位移受限)，最终影响扬声器的最大可输出声压。
在本发明实施方式中，相对图1而言改变了执行器分支的形状和布置方式，使得在在扬声器所占面积有限的情况下，提高了执行器的等效长度和等效弯曲柔度，因此提高了执行器的最大位移和相应的负载盘位移，最终提高扬声器的输出声压。
图2A是根据本发明实施方式的一种扬声器结构的爆炸视图，图2B是图2A中执行器结构12的材料层示意图。
现将图2A中展示的结构细节描述如下：
10：扬声器的能量转换结构层，其中具体包含了如下的部件11至15。
11：框架，该部分对执行器起到支撑并实现执行器的电学互连的作用。
12：执行器，扬声器中的电能-声能的耦合及相互转化发生在该部分中，具体的，执行器可将输入到其中的电能转化成机械振动(声能)。
13：负载盘：该结构本身不进行电能-声能的耦合及相互转化，只被动的接受由执行器产生的振动能量，将执行器能量传导至振动膜层。
14：第一连接部：该部分用于连接负载盘13和执行器12。
15：第二连接部：该部分用于连接框架11和执行器12。
扬声器的其他部件包括如下的20至70。
20：扬声器的能量传导块：该结构用于传导振动能量，根据具体结构设计，该部分有时可以省略。
30：下限位层，包含下外围部分31和向内侧的环形突出部32。
40：能量交换界面层，具体包含：
41：具有环形拱起结构的外围，具体包含：与下外围部分31的环状 搭接部分44，以及具有环状拱起的弹性部43。
42：振动膜层，该层充当扬声器与外界声媒质(通常是空气)交换声能的界面，具体的，膜层通过振动将声波能量传入空气。
50：上限位层：包含上外围部分51和向内侧的环形突出部52
60：PCB板：包含PCB主体和分布于其中的电学链接部或芯片如ASIC等。
70：防护层结构。
上述的扬声器，基本工作过程如下：首先控制信号由外界传导至扬声器PCB板60，并由其中的信号转换/处理芯片62接收并处理，经处理转换放大等流程后生成的的电信号经由PCB板60与框架11之间的电学触点进入执行器12，并在执行器12中被转化为机械振动。执行器12的振动能量会经由第一连接部14传导至负载盘13，再通过能量传导块20或直接由负载盘13传输至振动膜层42，振动膜层42的振动能量最终进入扬声器外部媒质，如空气。
本发明实施方式给出的扬声器能量转换结构层10的结构中，其中图5所示一种结构同时示于图2B中并且在下文中有进一步说明。除此之外本发明实施方式提供扬声器的能量转换结构层10还有其他各种可选方式，负载盘和执行器可以位于同一平面。以下结合附图加以说明。
本发明实方式中的一类扬声器能量转换结构层中，负载盘为多边形、圆形、或椭圆形，执行器的各分支为条形并且沿着负载盘的边缘的延伸方向设置。因为执行器的各部分通常是同步运动，所以在本文的描述中将各个不直接相连的部分视作属于同一执行器，认为其是该执行器的分支。以下对本发明实方式中的一类扬声器能量转换结构层的各种具体方式，特别是负载盘和执行器的结构，分别加以说明。
图2B是图2A中执行器结构12的材料层示意图。如图2B所示，执行器12a中包含四层结构，分别为偏置层12-1、下电极12-2、压电层12-3、 上电极12-4。偏置层用于偏置整体执行器的纵向中性轴，使得压电层的面内应力产生执行器的面外位移，同时起到对执行器薄膜结构的支撑作用。材料可选用单晶硅，二氧化硅，氮化铝以及钼，铝，金等金属。执行器的下电极的材料可选钼，铂，铝，金，钨，钌等。执行器的上电极材料可选钼，铂，铝，金，钨，钌等。
压电层可采用氮化铝、氧化锌，以及上述材料的稀土元素参杂材料(如一定原子比的钪掺杂)，也可采用锆钛酸铅、掺杂锆钛酸铅、铌酸锂、钽酸锂、聚偏氟乙烯(pvdf)等。需要指出的是，执行器在厚度方向为薄膜结构，即纵向厚度一般不超过100微米。由于执行器为薄膜结构，其纵向的弯曲模量较小，因此能够输出较大的声压。电极和压电层一般采用薄膜制作工艺得到。
图3A是根据本发明实施方式的一种能量转换结构层的主要部件的示意图。如图3A所示，负载盘13具有矩形或正方形结构，在负载盘13边缘靠近顶点的位置上具有4个矩形连接部14，4个矩形执行器12的长边与矩形负载盘13的4个边缘保持基本平行，每个执行器12和中央负载盘13之间动过1个连接部14相连，其中链接部14一边连接至负载盘13，另一边连接至执行器12的一端，而执行器12的另一端连接至框架11的内侧边缘。该排布方式能在确保执行器12产生足够振幅的前提下，使由执行器12和负载盘13构成的结构变得尽量紧凑，从而缩小其空间占用量。
图3B是图3A所示结构在工作时的一个瞬时状态的立体视图，在该视图中，中央负载盘沿Z轴正方向发生位移，而四周的执行器绕其位于框架内边缘的固定点向上发生微小摆动。显然图中所示的负载盘和执行器也可以形成与图示相反的位移状态。对于扬声器来说，是四周的执行器带动负载盘沿Z轴运动。
事实上，中央的负载盘和其周边的执行器的Z向运动还同时伴随着执行器在水平方向的微小伸缩/摆动以及负载盘在水平面内的微小转动，并且 这些运动时相关联的，如果其中一个运动方式的幅度受到限制，其它的方式运动的幅度也会受到限制。对于扬声器来说，因为通常希望负载盘13和执行器12可以在Z方向具有较大的振动幅度，所以需要降低中央负载盘和执行器在水平方向受到的制约。上述制约主要来自负载盘13和执行器12的连接部以及执行器和和框架11的内边缘连接处。因此本发明实施方式中给出一种可增加负载盘和执行器水平运动自由度的改进结构，如图3C所示，图3C是根据本发明实施方式的又一种执行器的结构的示意图。
图3C所示的结构中，连接部14中存在一条弯曲的镂空狭缝，该狭缝可以提高连接部的机械柔性。该狭缝与执行器12和负载盘13之间的间隙相连通，同时在所示狭缝位于连接部14内部的末端具有圆形倒角，该倒角可防止应力堆积在狭缝末端处形成裂纹。图3C中的改进结构有助于执行器12和负载盘13进行更大幅度的水平运动，从而提高了12和13在Z方向上的运动幅度。
负载盘的结构除了矩形以外，可以是其他多边形，例如图4所示，图4是根据本发明实施方式的又一种能量转换结构层的主要部件的示意图，其中负载盘13具有正六边形结构，在负载盘13边缘靠近顶点的位置上具有6个直角梯形连接部14，其中梯形连接部的倾斜腰在方向上为该连接部所在六边形边的邻边的顺延，6个矩形执行器12的长边与正六边形负载盘13的6个边缘保持基本平行，每个执行器12和中央负载盘13之间动过1个连接部14相连，其中连接部14一边(梯形的长底边)连接至负载盘13，另一边连(梯形垂直于底边的腰)接至执行器12的一端，而执行器12的另一端连接至框架11的内侧边缘。该排布方式可以在确保执行器12产生足够振幅的前提下，使由执行器12和负载盘13构成的结构变得尽量紧凑，从而缩小其空间占用量。与图3相比，执行器和连接部的数目更多，因此负载盘的实际振动状态更符合理想振动状态，如除主振动的其他寄生振动更小等，最终表现为振动更平稳、更可靠。
负载盘的结构除了多边形以外，也可以是圆形或椭圆形，只要执行器 的分支沿着负载盘边缘设置，使结构紧凑即可。例如图5所示，图5是根据本发明实施方式的又一种能量转换结构层的主要部件的示意图，其中，中央负载盘13为圆形，4个连接部14均匀的排布在圆周上，此外4个连接部15均匀排布在框架11的圆形内边缘上，且圆形负载盘13与框架11圆形内边缘同心。每一对连接部(14和15)之间连接有一个部分环形的执行器12分支，且每个分支的内外侧边缘与圆形负载盘13同心。显然，图5中所示的执行器12的分支的数量和相应的连接部14和15的数量不仅限于4个，可以根据实际情况发生变化，例如4A所示的结构中可设置3个，5个，6个执行器等等。执行器的数目越多，振动越平稳可靠。
在负载盘为圆形或椭圆形的情况下，执行器的分支也可以有更复杂的形状，其中包含多个弧形分支，这些弧形分支构成包围负载盘的由内向外的一层或几层包围圈，这样可使得执行器分支有更长的长度，相应能够使负载盘有更大的振动幅度。以下举例加以说明。
图6A是根据本发明实施方式的一种负载盘和执行器的结构的示意图。如图6A所示，负载盘1为圆形，其外部有两圈执行器分支6。负载盘与执行器分支6之间有连接部3，执行器分支6与框架(即上文中的框架11，图6A中未示出)之间有连接部4。执行器分支6又可以分为上下两组，每组整体呈半圆弧，而且每组各包含2个两端对应连接的半圆弧分支从而构成从负载盘1起自内而外的两层。图6A中的连接部，以及本文中其他各图中的连接部，都具有相对较小的面积，使被连接的部分之间形成尽可能柔性的连接，提高运动自由度。
图6B是图6A所示结构在工作时的位移的示意图。按图中的视角，执行器和负载盘1上下振动，颜色越深表示向上的位移越大，本文其他各个表示工作时位移的示意图中的颜色含义也如此。可以看出，在执行器与框架的连接部4，位移最小，执行器分支各部分的位移沿着分支向负载盘延伸的方向逐渐增大，这样，在执行器分支有较长的等效长度的情况下，在振动时负载盘相应会有更大的位移。
图7A是根据本发明实施方式的另一种负载盘和执行器的结构的示意图。如图7A所示，执行器分支7分为四组，每组整体呈四分之一圆弧，而且每组各包含2个两端对应连接的半圆弧分支从而构成从负载盘1起自内而外的两层。图7B是图7A所示结构在工作时的位移的示意图。和图6B类似，执行器与框架的连接部4的位移最小，负载盘的位移最大。
图8A是根据本发明实施方式的另一种负载盘和执行器的结构的示意图。如图8A所示，执行器分支8分为四组，每组整体呈半圆弧，而且每组各包含2个两端对应连接的半圆弧分支从而构成从负载盘1起自内而外的四层。内圈的组和外圈的组之间有连接部3。图8B是图8A所示结构在工作时的位移的示意图。和图8B类似，执行器与框架的连接部4的位移最小，负载盘的位移最大。
对于采用条形分支的执行器，一种可选的形式如图9A所示，图9A是根据本发明实施方式的又一种负载盘和执行器的结构的示意图，其中负载盘1的一组对边的外侧，由内向外设置有两层执行器的条形分支，内层的条形分支与负载盘之间有连接部4，与外层的条形分支之间有连接部3，外层的条形分支的两端5连接至能量转换结构层的框架(即上文中的框架11，图中未示出)。图9B是图9A所示结构在工作时的位移的示意图。从图中可以看出，自执行器分支与框架连接的位置起，至负载盘，整个结构的位移逐渐增大。
图9A所示结构可看作是负载盘一组对边各设置一组执行器的条形分支，每组2条分支。另外也可在负载盘四条边都设置一组执行器的条形分支，如图10A所示，图10A是根据本发明实施方式的又一种负载盘和执行器的结构的示意图，图10B是图10A所示结构在工作时的位移的示意图。图10A中，内层的条形分支两端连接至负载盘1顶点处，中间再与外围的条形分支经由连接部7连接，外围条形分支的两端5再与框架连接。
图11A是根据本发明实施方式的又一种负载盘和执行器的结构的示意图，图11B是图11A所示结构在工作时的位移的示意图。如图11A所示，执行器的4条分支8呈弓字形迂回转折，按图中视角左右、上下对称，使负载盘整体受力均匀。执行器各分支一端连接至负载盘的顶点，另一端5连接至框架。
负载盘可以是多边形(此处的多边形包括四边形)，并且边数为偶数，对于这样的负载盘，其周边可以沿负载盘的边的走向，环绕一层或多层的L形执行器分支，因为是要平行于负载盘的边，所以这里的L形可以是呈直角也可以是呈钝角，角度视负载盘的边数而定。以下举2例加以说明。
图12A是根据本发明实施方式的又一种负载盘和执行器的结构的示意图，图12B是图12A所示结构在工作时的位移的示意图。如图12A所示，执行器9的两组分支呈L形，沿负载盘1的对角线方向布置，每个L形分支还包含两段L形段，这样构成自负载盘1起自内向外的两层执行器分支，内层L形段一端连接至负载盘1的一个顶点，另一端与外层L形段的一端连接。从图12B可以看出，负载盘的受力点为一条对角线的端点，受力均匀。
图12A是执行器分支呈2层的情形，也可以是1层。以下再举一例。图12C是根据本发明实施方式的又一种负载盘和执行器在工作时的位移的示意图，其中执行器分支为1层；图12D是根据本发明实施方式的又一种负载盘和执行器在工作时的位移的示意图，其中执行器分支为2层。
执行器采用较多的层数有助于增大负载盘的竖直方向位移从而使其达到指标要求，这一点可以通过对比图12C和图12D看出来(12D的位移为12C位移的2倍)。另外，更多的负载盘边数或者更多的执行器分支数可减小或消除负载盘在竖直振动中发生的倾斜，使气流泄漏最小化，从而使声压强度提高，而且有助于保证负载盘运动的稳定性，在此表现为图12C和12D的运动稳定性和声压大于图12A和12B。同样地，为了进一步 提高声压和运动稳定性，执行器分支数(即执行器和负载盘相接的连接部数量)可以大于负载盘边数。
图13A是根据本发明实施方式的又一种负载盘和执行器的结构的示意图，其中负载盘1可以是矩形或正方形，执行器的框形分支包围负载盘1，二者之间有连接部，执行器还具有2个条形分支，分别与框形分支的一组对边具有连接部6，条形分支的两端5连接至能量转换结构层的框架(即上文中的框架11，图中未示出)。图13B是图13A所示结构在工作时的位移的示意图。从图中可以看出，自执行器分支与框架连接的位置起，至负载盘，整个结构的位移逐渐增大。
图14A是根据本发明实施方式的又一种负载盘和执行器的结构的示意图，图14B是图14A所示结构在工作时的位移的示意图。如图14A所示，负载盘1呈圆形，上下各有一条执行器2的分支，二者之间有连接部3，执行器2的分支的末端4用来连接至框架。在本发明实施方式中，执行器的分支也可以同时包含条形分支和弧形分支。例如图15A所示，图15A是根据本发明实施方式的又一种负载盘和执行器的结构的示意图，图15B是图15A所示结构在工作时的位移的示意图。与图14A相比，图15A中的执行器的分支与负载盘1之间还有半圆弧形的执行器分支5，其中部与条形分支之间具有连接部，两端分别与负载盘1有连接部。
根据图15A的结构，可以看出，图6A、图7A、图8A也可采用类似的方式，即在连接部4处与执行器的条状分支连接，该条状分支两端再连接至框架。
执行器和负载盘还可以有其他形式，例如图16A和图16B所示。图16A和图16B是根据本发明实施方式的螺旋形执行器的示意图。图16A中，负载盘13为圆形，执行器12连接于负载盘边缘并由中心向外旋绕成螺旋形。这种方式提高了空间利用率，并且使执行器的等效长度较长，从而有助于提高负载盘的振动幅度。图16B中，执行器12有两个分支，皆 连接于负载盘13的边缘并由中心向外旋绕成螺旋形。这种方式使执行器和负载盘组成的结构更具稳定性。
根据本发明实施方式的技术方案，执行器的分支位于负载盘的侧边，执行器的各分支可以沿着负载盘边缘的延伸方向设置，另外各分支还可采用迂回的形状，这些有助于更好地利用扬声器能量转换层的空间，从而使执行器有更大的有效长度和更高的等效弯曲柔度，提高了负载盘的振幅。在实际设计中，负载盘的形状不限于多边形、圆形、椭圆形。对于执行器和负载盘的面积，可以使二者之和大于扬声器所在芯片面积的80％，有助于保证执行器的有效长度和负载盘的面积，提高扬声器的输出声压。另外，执行器的所有分支的总长度可以不小于负载盘或整个扬声器芯片的周长，保证执行器的长度有助于提高扬声器的输出声压。
上述具体实施方式，并不构成对本发明保护范围的限制。本领域技术人员应该明白的是，取决于设计要求和其他因素，可以发生各种各样的修改、组合、子组合和替代。任何在本发明的精神和原则之内所作的修改、等同替换和改进等，均应包含在本发明保护范围之内。

Claims (19)

  1. 一种MEMS压电扬声器，包括负载盘和执行器，其特征在于，
    负载盘为多边形、圆形、或椭圆形，执行器的各分支为条形并且沿着负载盘的边缘的延伸方向设置。
  2. 根据权利要求1所述的MEMS压电扬声器，其特征在于，
    负载盘为多边形，执行器的分支数目与负载盘的边的数目一致；
    执行器的各分支的一端与负载盘之间具有连接部。
  3. 根据权利要求2所述的MEMS压电扬声器，其特征在于，
    所述连接部中存在一条镂空狭缝，该狭缝与执行器和负载盘之间的间隙相连通。
  4. 根据权利要求2所述的MEMS压电扬声器，其特征在于，
    所述狭缝位于连接部内部的末端具有圆形倒角。
  5. 根据权利要求1所述的MEMS压电扬声器，其特征在于，
    负载盘为矩形；
    执行器具有2个分支组并且设置在负载盘的一组对边，或者执行器具有4个分支组并且设置在负载盘的各边；
    所述分支组具有甲分支和乙分支，其中，甲分支的两端与所述扬声器的框架连接，甲分支的中部与乙分支的中部之间有连接部，乙分支的两端与负载盘之间有连接部。
  6. 根据权利要求1所述的MEMS压电扬声器，其特征在于，
    负载盘为圆形或椭圆形；
    执行器具有至少2个弧形分支；
    各弧形分支与负载盘之间、与所述扬声器的框架之间，分别具有连接部。
  7. 根据权利要求6所述的MEMS压电扬声器，其特征在于，
    执行器具有至少2个弧形分支，各弧形分支具有2个弧形段，第一弧形段两端分别连接第二弧形段两端；
    弧形分支与所述扬声器的框架之间的连接部位于第一弧形段中部；
    弧形分支与负载盘之间的连接部位于第二弧形段中部。
  8. 根据权利要求6所述的MEMS压电扬声器，其特征在于，
    执行器具有至少4个弧形分支并且形成包围负载盘的至少两层包围圈；
    各弧形分支具有2个弧形段，第一弧形段两端分别连接第二弧形段两端；
    最内层的包围圈的第一弧形段的中部与负载盘之间具有连接部；
    相邻包围圈之间具有连接部；
    最外层包围圈的第二弧形段的中部与所述扬声器的框架之间具有连接部。
  9. 一种MEMS压电扬声器，包括负载盘和执行器，其特征在于，
    负载盘为矩形或圆形；
    执行器具有矩形框状分支、第一分支、第二分支，其中：
    第一分支和第二分支的两端分别与所述扬声器的框架连接；
    负载盘位于矩形框状分支内，矩形框状分支的第一组对边的中部分别与负载盘之间有连接部；
    第一分支和第二分支位于矩形框状分支外，矩形框状分支的第二组对边的中部分别与第一分支和第二分支的中部之间有连接部。
  10. 一种MEMS压电扬声器，包括负载盘和执行器，其特征在于，
    负载盘为矩形；
    执行器具有4个弓字形转折的4个分支，两两设置在负载盘的一组对边；
    各分支的第一端与所述扬声器的框架连接，第二端分别与负载盘的一 个顶点连接；
    位于负载盘同一边的分支关于该边的中垂线呈轴对称设置。
  11. 一种MEMS压电扬声器，包括负载盘和执行器，其特征在于，
    负载盘为多边形，边数N为偶数；
    执行器具有N/2个L形分支，包围负载盘四周，负载盘的N个顶点中，每间隔1个顶点即有1个顶点与L形分支的端点连接；
    所述L形分支自负载盘起由内至外具有一层或多层，同一分支内的各层首层连接。
  12. 一种MEMS压电扬声器，包括负载盘和执行器，其特征在于，
    负载盘为圆形或椭圆形；
    执行器具有2个互相平行的条形分支，位于负载盘两侧；
    各条形分支的两端与所述扬声器的框架连接，中部与负载盘连接并且两个连接处的连线经过负载盘的圆心。
  13. 一种MEMS压电扬声器，包括负载盘和执行器，其特征在于，
    负载盘为圆形或椭圆形；
    执行器具有至少2个条形分支，以及至少2个弧形分支，弧形分支形成包围圈并且包围负载盘，条形分支位于该包围圈之外；
    各条形分支的两端与所述扬声器的框架连接；
    各条形分支的中部与弧形分支之间具有连接部；
    各弧形分支与负载盘之间具有连接部。
  14. 根据权利要求13所述的平面MEMS压电扬声器，其特征在于，
    执行器具有2个条形分支和2个弧形分支；
    弧形分支与负载盘之间的连接部位于弧形分支的端部。
  15. 一种MEMS压电扬声器，包括负载盘和执行器，其特征在于，负载盘为圆形或椭圆形；
    执行器盘绕负载盘，执行器为平面螺旋形或包含多个平面螺旋形分支。
  16. 根据权利要求1至15中任一项所述的MEMS压电扬声器，其特征在于，负载盘和执行器位于同一平面。
  17. 根据权利要求16所述的MEMS压电扬声器，其特征在于，执行器面积与负载盘的面积之和大于所述扬声器所在芯片面积的80％。
  18. 根据权利要求1至15中任一项所述的MEMS压电扬声器，其特征在于，执行器的所有分支的总长度不小于负载盘或整个扬声器芯片的周长。
  19. 根据权利要求18所述的MEMS压电扬声器，其特征在于，负载盘和执行器位于同一平面。
PCT/CN2020/101094 2020-07-09 2020-07-09 Mems压电扬声器 WO2022006816A1 (zh)

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Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN2369412Y (zh) * 1997-02-04 2000-03-15 焦秉立 曲线条型压电振子
US20110085684A1 (en) * 2009-10-12 2011-04-14 Samsung Electronics Co., Ltd. Piezoelectric micro speaker
CN102983781A (zh) * 2012-12-20 2013-03-20 北京航空航天大学 一种压电振动俘能器
CN103096226A (zh) * 2012-12-20 2013-05-08 歌尔声学股份有限公司 压电扬声器
CN111149372A (zh) * 2017-09-27 2020-05-12 第一精工株式会社 超声波传感器

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN2369412Y (zh) * 1997-02-04 2000-03-15 焦秉立 曲线条型压电振子
US20110085684A1 (en) * 2009-10-12 2011-04-14 Samsung Electronics Co., Ltd. Piezoelectric micro speaker
CN102983781A (zh) * 2012-12-20 2013-03-20 北京航空航天大学 一种压电振动俘能器
CN103096226A (zh) * 2012-12-20 2013-05-08 歌尔声学股份有限公司 压电扬声器
CN111149372A (zh) * 2017-09-27 2020-05-12 第一精工株式会社 超声波传感器

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