CN114125663B - Electroacoustic transducer, loudspeaker module and electronic equipment - Google Patents

Abstract

The application provides an electroacoustic transducer, a loudspeaker module and electronic equipment, so that the sensitivity of the electroacoustic transducer is improved. The electroacoustic transducer comprises a central magnet, two side magnets, a lower pole piece, two side pole pieces, a frame, a sound film, a voice coil and two flexible circuit boards, wherein the central magnet and the two side magnets are respectively arranged on the lower pole pieces; the central magnet comprises a first corner and a second corner which are arranged diagonally; the two side magnets are arranged around the first corner and the second corner in a centrosymmetric manner respectively, and a first gap is formed between each side magnet and the central magnet; the side pole pieces are arranged on one surface of the two side magnets, which is back to the lower pole piece; one surface of the frame is fixedly connected with one surface of the side pole piece, which is back to the lower pole piece, and the other surface of the frame is fixedly connected with the sound film; the voice coil is positioned on the inner side of the frame, one end of the voice coil is fixedly connected with the voice film, and the other end of the voice coil is inserted into the first gap; two flexible circuit board symmetric distribution are in the week side of voice coil loudspeaker voice coil, and flexible circuit board's one end is connected with the voice coil loudspeaker voice coil, and the other end is connected with the limit pole piece.

Description

Electroacoustic transducer, loudspeaker module and electronic equipment

The priority of the chinese patent application entitled "a speaker and electronic device" filed by the chinese patent office on 25/08/25/2020/63 and having application number 202010866796.4 is claimed in the present application and is incorporated herein by reference in its entirety.

Technical Field

The application relates to the technical field of electronic equipment, in particular to an electroacoustic transducer, a loudspeaker module and electronic equipment.

Background

The moving-coil micro-speaker is an electroacoustic transducer, and is a commonly used audio component of the current portable electronic equipment. As consumer demands for higher sound quality of electronic devices increase, speakers typically need to be designed with larger amplitudes. The loudspeaker comprises a voice coil and a magnetic circuit component for driving the voice coil to vibrate, wherein the driving capacity of the magnetic circuit component directly influences the amplitude of the loudspeaker, and is determined by the size of a magnet arranged on the magnetic circuit component. Among the prior art, the hole is revealed in the design of the bight position of speaker usually, consequently need carry out the magnetic circuit in bight position and dodge, and this whole size that just leads to the relative speaker of size of magnet is on the small side, and then leads to magnetic circuit assembly's driving force limited, is unfavorable for improving the sensitivity of speaker.

Disclosure of Invention

The application provides an electroacoustic transducer, a loudspeaker module and electronic equipment, which are used for improving the sensitivity of the electroacoustic transducer.

In a first aspect, the present application provides an electroacoustic transducer comprising a central magnet, two side magnets, a lower frame piece, side pole pieces, a frame, a sound membrane, and two flexible circuit boards. The central magnet is arranged on one surface of the lower pole piece, can be of a rectangular structure and comprises a first corner part and a second corner part, and the first corner part and the second corner part are arranged in a diagonal manner; the two side magnets are arranged on the same surface of the lower pole piece, the two side magnets are respectively positioned on the outer peripheral sides of the first corner and the second corner, the two side magnets are arranged in a central symmetry manner, and a first gap is formed between the side magnets and the central magnet; the side pole pieces are arranged on one side of the two side magnets, which is back to the lower pole piece; one side of the frame is fixedly connected with one side of the side pole piece, which is back to the lower pole piece, and the other side of the frame is fixedly connected with the periphery of the sound film so as to mutually fix the side pole piece and the sound film; the voice coil is positioned on the inner side of the frame and can be in a rectangular annular structure, one end of the voice coil is fixedly connected with the voice film, and the other end of the voice coil can be inserted into the first gap, so that the voice coil can vibrate under the action of a magnetic field generated by the central magnet and the side magnets when the voice coil is electrified; two flexible circuit board symmetric distribution are in the week side of voice coil loudspeaker voice coil, flexible circuit board's one end voice coil loudspeaker voice coil fixed connection, the other end and limit pole piece fixed connection.

Compared with the traditional scheme that the side magnets are arranged on the side face of the central magnet, the electroacoustic transducer in the scheme can fill the magnet missing of the outer peripheral sides of the two corners by arranging the two side magnets around the central magnet at the two diagonally arranged corners, so that the overall size of the magnet is increased, the magnetic induction intensity of the electroacoustic transducer can be effectively improved, the driving capability of the electroacoustic transducer is improved, and the electroacoustic transducer has better sensitivity.

When specifically setting up, center magnet and two limit magnets can be respectively through the top surface reciprocal anchorage of bonding mode with lower pole piece to reduce the equipment degree of difficulty.

In some possible embodiments, the electroacoustic transducer further comprises a central pole piece, wherein the central pole piece is arranged on a side of the central magnet, which faces away from the lower pole piece, so that a complete magnetic circuit can be formed between the central magnet and the side magnets, and a guarantee is provided for the stressed vibration of the voice coil.

In some possible embodiments, the central magnet includes a first side, a second side, a third side, and a fourth side, wherein the first side and the second side are adjacent to the first corner, and the third side and the fourth side are adjacent to the second corner. The side magnet comprises a first branch and a second branch, and the first branch and the second branch can be connected to form an L-shaped structure. When the magnetic pole is specifically arranged, the first branch and the second branch of one edge magnet are respectively positioned at the outer sides of the first side surface and the second side surface, and the first branch and the second branch of the other edge magnet are respectively positioned at the outer sides of the third side surface and the fourth side surface. Through setting up two limit magnets into L type structure, not only can fill the magnet of the periphery side in first bight and second bight and lack, still make each side of center magnet all have the limit magnet to encircle the setting to can obviously increase the size of magnet, be favorable to making electroacoustic transducer obtain better sensitivity.

In some possible embodiments, the central magnet further comprises a third corner and a fourth corner diagonally disposed, wherein the third corner is connected between the first side and the fourth side, and the fourth corner is connected between the second corner and the third corner. At this time, the first branch of one of the side magnets can extend to a position between the first corner part and the third corner part, and the second branch can extend to one end of the second side surface close to the fourth corner part; the first branch of the other side magnet can extend to the position between the second corner and the fourth corner, and the second branch can extend to the end, close to the third corner, of the fourth side, so that the size of the magnet can be further increased.

In some possible embodiments, the voice coil includes a third corner corresponding to the third corner of the center magnet, and a fourth corner corresponding to the fourth corner of the center magnet. And the two flexible circuit boards are respectively arranged on the outer peripheral sides of the third corner and the fourth corner, one end of each flexible circuit board is fixedly connected with the voice coil, and the other end of each flexible circuit board is fixedly connected with one side of the side pole piece facing the lower pole piece. In this scheme, two limit magnets are the relation that sets up with two flexible circuit board approximate dislocation, under the prerequisite in the all sides space of make full use of voice coil loudspeaker voice coil, can also improve the atress homogeneity of sound membrane to be favorable to improving electroacoustic transducer's audio.

When the flexible circuit board is specifically arranged, the flexible circuit board can comprise a first connecting portion, a second connecting portion and a third connecting portion which are sequentially connected, wherein the first connecting portion is fixedly connected with the voice coil, the second connecting portion is located on one side, away from the voice coil, of the first connecting portion, the third connecting portion is located on one side, away from the first connecting portion, of the second connecting portion, and the third connecting portion is fixedly connected with the side pole piece. The first notch and the second notch are symmetrically distributed on the edge pole piece, the first notch can expose the first connecting portion and part of the second connecting portion of one of the flexible circuit boards, and the second notch can expose the first connecting portion and part of the second connecting portion of the other flexible circuit board, so that an avoiding space is provided for the movement of the flexible circuit boards, and interference between the flexible circuit boards and the edge pole piece is avoided.

In some possible embodiments, the outer periphery of the first side surface and the outer periphery of the third side surface are respectively provided with an end, connected with the third connecting portion, of the corresponding flexible circuit board, and the end, connected with the third connecting portion, of the corresponding flexible circuit board is superposed on the first branch, and the position, corresponding to the end of the second connecting portion, of the first branch is provided with an avoiding groove. By adopting the arrangement, the avoiding groove can provide an avoiding space for the vibration of the second connecting part towards the lower pole piece direction so as to avoid the interference of the first branch on the movement of the second connecting part.

In addition, the positions of the side pole pieces corresponding to the two avoidance grooves can be provided with avoidance holes respectively, and the two avoidance holes can be communicated with the first notch and the second notch respectively during specific arrangement. Like this, dodge the hole and can provide for the vibration of second connecting portion back of the body to lower pole piece direction and dodge the space to avoid the limit pole piece to cause the interference to the motion of second connecting portion.

In some possible embodiments, the electroacoustic transducer may further include two auxiliary diaphragms, the two auxiliary diaphragms are respectively disposed on sides of the two flexible circuit boards facing away from the sound film, and one end of each auxiliary diaphragm may be fixedly connected to the ground connection portion of the corresponding flexible circuit board, and the other end of each auxiliary diaphragm is fixedly connected to the third connection portion of the corresponding flexible circuit board. Therefore, when the sound membrane vibrates, the auxiliary vibrating membrane synchronously vibrates under the driving of the flexible circuit board, so that the rolling vibration of the voice coil can be inhibited, and the electroacoustic transducer can obtain better sound quality.

In some possible embodiments, the sound film comprises a vibration part, the cross-sectional shape of the vibration part of the sound film is arc-shaped, and the vibration part of the sound film is convex back to the direction of the lower pole piece; the auxiliary vibrating diaphragm also comprises a vibrating part, the cross section of the vibrating part of the auxiliary vibrating diaphragm is arc-shaped, and the vibrating part of the auxiliary vibrating diaphragm is raised towards the direction of the lower pole piece. That is to say, the vibration part of the sound film and the vibration part of the auxiliary diaphragm are respectively convex towards different directions, so that the space below the sound film is released, the central magnet and the side magnet below the sound film are allowed to be provided with larger height dimensions, the magnetic induction intensity of the electroacoustic transducer is increased, and the sensitivity of the electroacoustic transducer is improved.

In some possible embodiments, the positions of the lower pole piece corresponding to the two auxiliary diaphragms may be respectively provided with a third gap and a fourth gap, so as to provide an avoidance space for the vibration of the auxiliary diaphragms in the direction of the lower pole piece, and avoid the interference of the lower pole piece on the motion of the auxiliary diaphragms.

In some possible embodiments, the electroacoustic transducer may further include a connection frame, the connection frame is located between the voice coil and the diaphragm, one end of the connection frame is fixedly connected to the voice coil, and the other end of the connection frame is fixedly connected to the diaphragm. Through setting up the connection frame, can keep apart voice coil loudspeaker voice coil and voice diaphragm for the voice diaphragm is kept away from the voice coil loudspeaker voice coil, and the connection frame can also play the heat dissipation effect to the voice coil loudspeaker voice coil in addition, thereby reduces the risk that causes the damage to the voice diaphragm because of the voice coil loudspeaker voice coil is overheated.

In a second aspect, the present application further provides a speaker module, which includes a box body and an electroacoustic transducer in any one of the possible embodiments, wherein the electroacoustic transducer is disposed in the box body, and the box body is provided with sound holes communicating the inside of the box body with the outside, so that sound emitted by the electroacoustic transducer can be transmitted to the outside of the box body through the sound holes. The driving capability of the magnet of the electroacoustic transducer is improved, so that the sensitivity of the loudspeaker module is higher.

The third aspect, this application still provides an electronic equipment, and this electronic equipment includes the speaker module among casing and the aforementioned embodiment, and the speaker module sets up in the casing, is provided with the sound-emitting hole on the casing, and the sound-emitting hole communicates sound outlet hole and electronic equipment's outside to the sound that makes electroacoustic transducer send can be transmitted to the electronic equipment outside through sound outlet hole and sound-emitting hole. Because the sensitivity of the loudspeaker module is higher, the tone quality of the electronic equipment is also improved.

In a third aspect, the present application additionally provides an electronic device, which includes a housing, a display module, and a receiver, where the receiver is disposed in the housing, and the receiver may be the electroacoustic transducer in the foregoing embodiments. The display module comprises a glass cover plate and a display panel, wherein the glass cover plate is fixed on one side of the shell, and the display panel is fixed on the inner surface, facing the shell, of the glass cover plate. The electronic equipment is provided with a telephone receiver, so that the sound emitted by the telephone receiver can be transmitted to the outside of the electronic equipment through the telephone receiver. When the telephone receiver is specifically arranged, the telephone receiver can be arranged on the cover plate, or the telephone receiver can be formed between the edge of the cover plate and the shell, or the telephone receiver can also be arranged on the shell. Because the sensitivity of the loudspeaker module is higher, the tone quality of the electronic equipment is also improved.

Drawings

Fig. 1 is a schematic structural diagram of an electronic device 1 provided in an embodiment of the present application;

FIG. 2 is a schematic structural diagram of a speaker module of the electronic device shown in FIG. 1;

FIG. 3 is an exploded view of the speaker module shown in FIG. 2;

fig. 4 is a schematic structural diagram of an electroacoustic transducer provided in an embodiment of the present application;

FIG. 5 is a partially exploded schematic view of the electro-acoustic transducer of FIG. 4;

FIG. 6 is a partially exploded schematic view of the vibration assembly of the electro-acoustic transducer shown in FIG. 4;

FIG. 7 isbase:Sub>A cross-sectional view of the vibrating assembly of the electro-acoustic transducer shown in FIG. 4 in the direction A-A;

FIG. 8 is a partially exploded schematic view of a magnetic circuit assembly of the electro-acoustic transducer shown in FIG. 4;

FIG. 9 is a partial schematic view of the electro-acoustic transducer of FIG. 4;

FIG. 10 isbase:Sub>A cross-sectional view of the electro-acoustic transducer shown in FIG. 4 in the direction A-A;

fig. 11 is a cross-sectional view of the electro-acoustic transducer shown in fig. 4 in the direction B-B.

Reference numerals:

1-an electronic device; 100-a housing; 200-a display module; 300-a receiver; 400-a camera module; 500-a speaker module;

600-a main board; 700-a battery; 110-middle frame; 120-rear cover; 1001-speaker hole; 210-a glass cover plate; 220-a display panel;

2101-light transmissive region; 2102-receiver; 510-an electroacoustic transducer; 520-a cartridge; 530-a cover; 540-circuit board;

521-sound outlet; 522-slotting; 523-convex; 10-a frame; 20-a vibration assembly; 30-a magnetic circuit assembly; 21-a sound membrane;

22-a connecting frame; 23-a voice coil; 24. 24a, 24 b-a flexible circuit board; 25-an auxiliary diaphragm; 211-a diaphragm; 212-ball top;

213-a first fixed part of the diaphragm; 214-a vibrating portion of the diaphragm; 215-a second fixed part of the diaphragm; 221-a body;

222-an extension; 241-a first connection; 242 — a second connecting portion; 243-third connecting part;

2411-an arc segment of the first connection; 2412-a straight line segment of the first connection; 2421 — an arc segment of the second connection;

2422-straight section of second connection; 251-a first fixing portion of the auxiliary diaphragm; 252-a vibrating part of the auxiliary diaphragm;

253-a second fixing portion of the auxiliary diaphragm; 31-a central pole piece; 32-edge pole piece; 33-a central magnet;

34. 34a, 34 b-edge magnets; 35-lower pole piece; 36-a first gap; 341-first branch; 342-a second branch;

331-a first side; 332-a second side; 333-a third side; 334-fourth side; 37-a communicating space;

38-a second gap; 321-a first notch; 322-a second gap; 351-a third gap; 352-fourth gap;

343-a first avoidance slot; 323-second avoidance slot; 344-a third avoidance slot; 324-fourth avoidance slot.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application.

The embodiment of the application provides an electric energy sound converter, and the electric energy sound converter is used for converting an electric signal into a sound signal. This electric energy sound converter has increased the area and the volume of magnet through optimizing the structure and the relative position of magnetic circuit subassembly and flexible circuit board to can promote magnetic circuit subassembly's driving force, make the electric energy sound converter have the sensitivity of preferred. The embodiment of the application also provides an electronic device comprising the electroacoustic transducer. The electronic device can be a mobile phone, a tablet computer, a notebook computer, a wearable device, a walkman and other products with a sound playing function. The wearable device can be an intelligent bracelet, an intelligent watch, an intelligent head display, intelligent glasses and the like. For example, the electroacoustic transducer can be applied to an electronic device as a speaker core of a speaker module (also referred to as a loudspeaker) and can also be applied to an electronic device as a receiver (also referred to as an earphone).

Referring to fig. 1, fig. 1 is a schematic structural diagram of an electronic device 1 according to an embodiment of the present disclosure. The electronic device 1 shown in fig. 1 is described by taking a mobile phone as an example. The electronic device includes a housing 100, a display module 200, a receiver 300, a camera module 400, a speaker module 500, a main board 600 and a battery 700. It should be noted that fig. 1 and the following related drawings only schematically show some components included in the electronic device 1, and the actual shape, the actual size, the actual position, and the actual configuration of the components are not limited by fig. 1 and the following drawings.

The housing 100 includes a middle frame 110 and a rear cover 120, and the rear cover 120 is fixed to one side of the middle frame 110. In one embodiment, the rear cover 120 may be fixed to the middle frame 110 by an assembling method. In another embodiment, the rear cover 120 and the middle frame 110 may be formed as a single-piece structure. The case 100 is provided with the speaker holes 1001, and the number of the speaker holes 1001 may be one or more. Illustratively, the number of the sound emitting holes 1001 is plural, and the plural sound emitting holes 1001 are opened in the center frame 110. The speaker hole 1001 may communicate the inside and the outside of the electronic device 1.

The display module 200 is fixed on a side of the middle frame 110 away from the rear cover. At this time, the display module 200 is disposed opposite to the rear cover 120, and the display module 200, the middle frame 110 and the rear cover 120 enclose the inside of the electronic device 1 together. The display module 200 includes a glass cover 210 and a display panel 220, wherein the glass cover 210 is stacked on a side of the display panel 220 facing away from the middle frame 110. The display panel 220 is used to display an image, and the display panel 220 may further integrate a touch function. The glass cover 210 may be disposed adjacent to the display panel 220, and is mainly used for protecting the display panel 220 and preventing dust. The glass cover plate 210 is provided with a light transmission region 2101 and a receiver hole 2102, the light transmission region 2101 can allow light to pass through, and exemplarily, an ink layer of the glass cover plate 210 is hollowed in a region where the light transmission region 2101 is located; the receiver 2102 is a through hole penetrating the glass cover 210.

In other embodiments, a telephone receiver is formed between the edge of the glass cover 210 and the housing 10. For example, the edge of the glass cover 210 on the top of the electronic device 1 and the edge of the middle frame 110 of the casing 100 on the top of the electronic device 1 form a telephone receiver. In other embodiments, the housing 1 is provided with a telephone receiver. For example, the middle frame 110 of the housing 1 forms a telephone receiver at an area on the top of the electronic device 1. The specific forming structure and the position of the telephone receiver are not strictly limited.

The receiver 300 is disposed inside the housing 100. The receiver 300 is located between the display module 200 and the rear cover 120. The sound emitted by the receiver 300 is transmitted to the outside of the electronic device 1 through the receiver hole 2102, so as to realize the sound playing function of the electronic device 1. Illustratively, the receiver 300 may employ an electroacoustic transducer as described in the embodiments below. In other embodiments, the receiver 300 may also adopt electroacoustic transducers with other structures.

The camera module 400 is housed inside the housing 100. The camera module 400 is located between the display module 200 and the rear cover 120. The camera module 400 collects light through the transparent region of the glass cover 210 to perform photographing. The electronic device 1 may further include another camera module accommodated in the housing 100, the rear cover 120 may be provided with a shooting through hole, and the another camera module may collect light through the shooting through hole to shoot.

The speaker module 500 is accommodated in the housing 100. The speaker module 500 is located between the display module 200 and the rear cover 120. The sound emitted by the speaker module 500 can be transmitted to the outside of the electronic device 1 through the sound emitting hole 1001, so as to realize the sound playing function of the electronic device 1. The speaker module 500 includes a speaker core that may employ an electroacoustic transducer 510 as described in the embodiments below. In other embodiments, the speaker core may employ electroacoustic transducers of other configurations.

Both the main board 600 and the battery 700 are housed inside the case 100. The main board 600 is located on one side of the battery 700, and illustratively, the main board 600 is located on the upper portion of the electronic device 1, and the battery 700 is located on the lower portion of the electronic device 1. The battery 700 is used to power the electronic device 1. The main board 600 may be a hard main board, a flexible main board, or a hard and soft combined main board. In addition, the motherboard 600 may be used to configure a chip, and the chip may be a Central Processing Unit (CPU), a Graphics Processing Unit (GPU), a Universal Flash Storage (UFS), and the like. The functional modules of the electronic apparatus 1, such as the display module 200, the camera module 400, the speaker module 500, and the receiver 300, are coupled to the CPU.

Referring to fig. 2 and fig. 3 together, fig. 2 is a schematic structural diagram of a speaker module of the electronic device shown in fig. 1, and fig. 3 is an exploded schematic diagram of the speaker module shown in fig. 2.

The speaker module 500 includes an electroacoustic transducer 510, a case 520, a cover 530, and a circuit board 540. The cover 530 is disposed at one side of the case 520, and the cover and the case are fixedly connected to form a sound box. An electroacoustic transducer 510 is located inside the enclosure. One end of the circuit board 540 is located inside the sound box for connecting the electroacoustic transducer 510; the other end of the circuit board 540 is located outside the speaker box to electrically connect the electroacoustic transducer 510 with external devices of the speaker module 500. Illustratively, the end of the circuit board 540 outside the enclosure may be fixed and electrically connected to the motherboard.

A sound outlet hole 521 is formed in the side surface of the box body 520, and the sound outlet hole 521 communicates the inside of the sound box with the outside of the sound box. The sound emitted from the electroacoustic transducer 510 can be transmitted to the outside of the cabinet through the sound output hole 521. Referring to fig. 1, the sound emitting hole 1001 of the housing 100 communicates the sound emitting hole 521 of the speaker module 500 with the outside of the electronic device 1, and the sound emitted by the electroacoustic transducer 510 can be transmitted to the outside of the electronic device 1 through the sound emitting hole 521 and the sound emitting hole 1001.

One end of the box 520 facing the cover 530 is further provided with a slot 522 communicating the inside of the sound box and the outside of the sound box, and the circuit board 540 can specifically extend out of the sound box through the slot 522. The circuit board 540 may be a flexible circuit board, and in specific implementation, a protrusion 523 is disposed in the box body 520 and faces the cover 530, one end of the protrusion 523 is disposed near the slot 522, the other end of the protrusion is disposed near the electroacoustic transducer 510, and a portion of the circuit board 540 located in the sound box is disposed on an end surface of the protrusion 523, so that the circuit board 540 can be stably fixed in the sound box, and the risk of damage to the circuit board 540 due to shaking is reduced. In addition, the end of the circuit board 540 located inside the sound box may include two branches, and the ends of the two branches are respectively formed as two connection ends connected to the electroacoustic transducer 510.

Referring to fig. 4 and fig. 5 together, fig. 4 is a schematic structural diagram of an electroacoustic transducer provided in an embodiment of the present application, and fig. 5 is a partially exploded schematic diagram of the electroacoustic transducer shown in fig. 4. In the embodiment of the present application, the x direction is defined as the length direction of the electroacoustic transducer 510, the y direction is defined as the width direction of the electroacoustic transducer 510, and the z direction is defined as the thickness direction of the electroacoustic transducer 510. It should be noted that the terms "top" and "bottom" used in the electroacoustic transducer 510 according to the embodiment of the present application are mainly explained according to the illustrated orientation of the electroacoustic transducer 510 in fig. 4, and do not form a limitation on the orientation of the electroacoustic transducer 510 in the practical application scenario.

The electroacoustic transducer 510 includes a frame 10, a vibration assembly 20, and a magnetic circuit assembly 30, wherein the vibration assembly 20 and the magnetic circuit assembly 30 are respectively mounted on the frame 10. The parts of the components of the vibration assembly 20 connected to the frame 10 are fixed with respect to the frame 10, and the remaining parts can vibrate with respect to the frame 10. The magnetic circuit assembly 30 is fixed relative to the frame 10, and the magnetic circuit assembly 30 can be used to provide a driving magnetic field for the vibration assembly 20.

Referring to fig. 6, fig. 6 is a partially exploded view of the vibrating assembly of the electro-acoustic transducer shown in fig. 4. The vibration assembly 20 of the electroacoustic transducer includes a diaphragm 21, a connection frame 22, a voice coil 23, two flexible circuit boards 24, and two auxiliary diaphragms 25. The voice coil 23 may have a substantially rectangular ring structure, and for example, the voice coil 23 may have a rounded rectangular ring shape. The voice coil 23 includes four straight sides and four corner portions, and a corner portion is connected between two adjacent straight sides. In the present embodiment, the voice coil 23 is inserted into the magnetic circuit assembly, and under the action of the magnetic field provided by the magnetic circuit assembly, an ampere force is generated when the voice coil 23 is energized, and then other components of the vibration assembly are driven to vibrate.

The sound film 21 includes a diaphragm 211 and a dome 212. The diaphragm 211 is substantially rectangular and annular, and includes a first fixing portion 213, a vibrating portion 214, and a second fixing portion 215, wherein the first fixing portion 213 is located at an inner side of the vibrating portion 214, and the second fixing portion 215 is located at an outer side of the vibrating portion 214. The first fixing portion 213 of the diaphragm 211 is fixedly connected to the dome 212, the second fixing portion 215 is fixedly connected to the frame, and when the diaphragm is specifically disposed, the dome 212 is connected to the top surface of the first fixing portion 213, and the frame is connected to the bottom surface of the second fixing portion 215. The cross-sectional shape of the vibration portion 214 of the diaphragm 211 is an arc shape or an approximately arc shape, the extending track of the vibration portion 214 is a rounded rectangle, and the vibration portion 214 is disposed convexly, that is, the vibration portion 214 protrudes toward a direction away from the voice coil 23. The vibration part 214 can be deformed when receiving an external force, so that the first fixing part 213 and the dome 212 move relative to the second fixing part 215.

The connection frame 22 may be used to connect the voice coil 23 with the diaphragm 21, and specifically, the connection frame 22 includes a body 221 and an extension portion 222, the body 221 has a shape of a substantially rectangular ring matching the voice coil 23, one end of the body 221 is connected to an end surface of the voice coil 23 facing the diaphragm 21, and the other end of the body 221 is connected to an end surface of the diaphragm 21 facing the voice coil 23. The extension 222 is disposed at an end of the body 221 facing the voice coil 23, and when the body 221 is fixed to the voice coil 23, the extension 222 is attached to an outer peripheral surface of the voice coil 23. The number of the extending portions 222 may be one or more, for example, the number of the extending portions 222 is two as shown in fig. 6, and the two extending portions 222 may be symmetrically disposed near two opposite corners of the body 221, so that after the body 221 and the voice coil 23 are assembled, the two extending portions 222 may be respectively attached and fixed to the outer circumferential surfaces of two corners of the voice coil 23 disposed at opposite corners, thereby improving the connection strength between the connection frame 22 and the voice coil 23 on the premise of ensuring the force uniformity of the voice coil 23. By arranging the connection frame 22, the voice coil 23 can be isolated from the voice diaphragm 21, so that the voice diaphragm 21 is far away from the voice coil 23, and in addition, the connection frame 22 can also play a role in heat dissipation on the voice coil 23, thereby reducing the risk of damage to the voice diaphragm 21 caused by overheating of the voice coil 23.

Referring to fig. 6 again, the two flexible circuit boards 24 have the same structure, and the two flexible circuit boards 24 are disposed on the outer periphery of the voice coil 23 in a central symmetry manner, and exemplarily, the two flexible circuit boards 24 are disposed near two corners of the voice coil 23 which are disposed diagonally. Two ends of the lead of the voice coil 23 can be respectively electrically connected to two flexible circuit boards 24, and the two flexible circuit boards 24 are electrically connected with the circuit boards so as to realize the electrical connection with the external devices of the electroacoustic transducer. Alternatively, both ends of the lead of the voice coil 23 may be electrically connected to one of the flexible circuit boards 24, and the flexible circuit board 24 is electrically connected to the aforementioned circuit board, so as to electrically connect to a device external to the electroacoustic transducer.

In a specific implementation, the flexible circuit board 24 includes a first connection portion 241, a second connection portion 242 and a third connection portion 243, and the second connection portion 242 is connected between the first connection portion 214 and the third connection portion 243. The first connection portion 241, the second connection portion 242, and the third connection portion 243 are substantially bar-shaped, the first connection portion 241 is connected to an outer circumferential surface of a corresponding corner portion of the voice coil 23, and in order to increase a contact area between the first connection portion 241 and the voice coil 23, a head end of the first connection portion 241 may extend to an outer side surface of the voice coil 23 adjacent to the corresponding corner portion and extending in the first direction (i.e., the width direction y of the electroacoustic transducer). The head end of the second connection portion 242 is connected to the tail end of the first connection portion 241, the second connection portion 242 is located on the side of the first connection portion 241 far away from the voice coil 23, and the second connection portion 242 and the first connection portion 241 are spaced apart from each other. The head end of the third connecting portion 243 is connected to the tail end of the second connecting portion 242, the third connecting portion 243 is located on the side of the second connecting portion 242 away from the first connecting portion 241, and the third connecting portion 243 and the second connecting portion 242 are spaced apart from each other. Illustratively, the connection position of the first connection portion 241 and the second connection portion 242 is substantially U-shaped, and the connection position of the second connection portion 242 and the third connection portion 243 is also substantially U-shaped.

In addition, when the voice coil 23 has a rounded rectangular structure, the first connection portion 241 and the second connection portion 242 may include arc segments and straight segments, respectively, in order to better match the shape of the outer circumferential surface of the voice coil 23. The straight line segment 2412 of the first connecting part 241 is arranged close to the head end thereof, and the arc segment 2411 of the first connecting part 241 is arranged close to the tail end thereof; the arc 2421 of the second connecting portion 242 is disposed near the head thereof, and the straight 2422 of the second connecting portion 242 is disposed near the tail thereof. The third connecting portion 243 is substantially L-shaped, a corner of the third connecting portion 243 is located outside the arc line segment of the second connecting portion 242, and a corner of the third connecting portion 243 is a rounded corner. In the present embodiment, the arc 2411 of the first connection portion 241, the arc 2421 of the second connection portion 242, and the corner of the third connection portion 243 are all disposed coaxially with the corresponding corner of the voice coil 23. It will be appreciated that the coaxial arrangement of the two structures means that the central axes (or centerlines) of the two structures coincide, allowing for slight deviations due to manufacturing tolerances, assembly tolerances, etc.

In this embodiment, since the arc segment 2411 of the first connection portion 241, the arc segment 2421 of the second connection portion 242 and the corner of the third connection portion 243 are coaxially disposed with the corresponding corner of the voice coil 23, when the voice coil 23 drives the flexible circuit board 24 to vibrate, the shape of the flexible circuit board 24 can better adapt to the deformation and displacement requirements, so that the flexible circuit board 24 has better reliability and longer service life. In addition, adopt this kind of setting, also make the outside space in each connecting portion can make full use of the bight of voice coil 23 to can arrange longer size's line of walking, make flexible circuit board 24 when vibrating along with voice coil 23 by a wide margin, stress is less, and flexible circuit board 24's reliability is higher.

Fig. 7 isbase:Sub>A sectional view ofbase:Sub>A vibration assembly of the electro-acoustic transducer shown in fig. 4 inbase:Sub>A directionbase:Sub>A-base:Sub>A. Referring to fig. 6 and 7 together, the two auxiliary diaphragms 25 have the same structure, and the two auxiliary diaphragms 25 are respectively disposed corresponding to the two flexible circuit boards 24, specifically, the two auxiliary diaphragms 25 are respectively disposed on one side of the bottom surfaces of the corresponding flexible circuit boards 24. The auxiliary diaphragm 25 includes a first fixing portion 251, a vibrating portion 252, and a second fixing portion 253, wherein the first fixing portion 251 is located at an inner side of the vibrating portion 252, and the second fixing portion 253 is located at an outer side of the vibrating portion 252. The extending track of the auxiliary diaphragm 25 matches the track of the first connection portion 241, the first fixing portion 251 of the auxiliary diaphragm 25 is fixedly connected with the first connection portion 241 of the corresponding flexible circuit board 24, and the second fixing portion 253 is fixedly connected with the third connection portion 243 of the corresponding flexible circuit board 24. The sectional shape of the vibration portion of the auxiliary diaphragm 25 is an arc or an approximate arc, and the vibration portion 252 is concave, that is, the vibration portion 252 is convex in a direction away from the flexible circuit board 24. The vibration portion 252 of the auxiliary diaphragm 25 can be deformed when an external force is applied, so that the first fixing portion 251 and the second fixing portion 253 of the auxiliary diaphragm 25 move relative to each other.

Referring to fig. 8, fig. 8 is a partially exploded schematic view of a magnetic circuit assembly of the electroacoustic transducer shown in fig. 4. The magnetic circuit assembly 30 of the electro-acoustic transducer includes a central pole piece 31, side pole pieces 32, a central magnet 33, two side magnets 34, and a lower pole piece 35. The central pole piece 31, the side pole pieces 32 and the lower pole piece 35 are magnetic conductive members, and the central magnet 33 and the two side magnets 34 are permanent magnets.

In specific implementation, the central magnet 33 and the two side magnets 34 are respectively disposed on the top surface of the lower pole piece 35, and each magnet can be fixed to the top surface of the lower pole piece 35 by adhesion. The central magnet 33 has a substantially rectangular configuration, and the central magnet 33 may have a rounded rectangular configuration, for example. The central magnet 33 includes four side faces and four corner portions, and one corner portion is connected between two adjacent side faces. The two side magnets 34 are disposed on the outer peripheral side of the center magnet 33 in a centrosymmetric manner, and a first gap 36 is formed between the two side magnets 34 and the center magnet 33. Illustratively, the two side magnets 34 may be disposed around two corners of the center magnet 33, respectively, which are diagonally disposed.

The side magnet 34 comprises a first branch 341 arranged in a first direction, i.e. the width direction y of the electroacoustic transducer, and a second branch 342 arranged in a second direction, i.e. the length direction x of the electroacoustic transducer, i.e. the side magnet 34 is arranged substantially in an L-shape. In a specific implementation, for the side magnet 34a located on the left side of the central magnet 33, the first branch 341 is located outside the first side surface 331 of the central magnet 33, and the second branch 342 is located outside the second side surface 332 of the central magnet 33, that is, the side magnet 34a is disposed around the first corner a between the first side surface 331 and the second side surface 332; for the side magnet 34B located on the right side of the center magnet 33, the first branch 341 is located outside the third side surface 333 of the center magnet 33, and the second branch 342 is located outside the fourth side surface 334 of the center magnet 33, that is, the side magnet 34B is disposed around the second corner B between the third side surface 333 and the fourth side surface 334. When the central magnet 33 has a round-corner rectangular structure, the corner of the connecting position of the first branch 341 and the second branch 342 is also round-corner, and the round-corner is disposed coaxially with the corresponding corner of the central magnet 33, so that the shapes of the outer peripheral surfaces of the side magnets 34 and the central magnet 33 can be better matched, and a magnetic field with uniform strength can be formed in the first gap 36 between the side magnets 34 and the central magnet 33. It is understood that the first side 331 and the third side 333 of the center magnet 33 are sides disposed along the y-axis direction, and the second side 332 and the fourth side 334 of the center magnet 33 are sides disposed along the x-axis direction.

In addition, on the first side surface 331 of the central magnet 33, the corresponding first branch 341 extends to a position between the first corner portion a and the third corner portion C, for example, a position near the middle region of the first side surface 331; on the fourth side 334 of the central magnet 33, the corresponding second branch 342 extends substantially to an end of the fourth side 334 near a third corner C between the first side 331 and the fourth side 334. Similarly, at the third side 333 of the central magnet 33, the corresponding first branch 341 extends to a position between the second corner B and the fourth corner D, for example, a position close to the middle region of the third side 333; at the second side 332 of the central magnet 33, the corresponding second branch 342 extends substantially to an end near a fourth corner D, wherein the fourth corner D of the central magnet 33 is the corner between the second side 332 and the third side 333. In this way, the third corner C and the fourth corner D of the center magnet 33 form communication spaces 37, respectively, and each communication space 37 communicates with the first gaps 36 between the two side magnets 34 on the left and right sides and the center magnet 33, respectively, and communicates with the outside of the magnetic circuit assembly 30.

With continued reference to fig. 8, central pole piece 31 is located on a side of central magnet 33 facing away from lower pole piece 35, and central pole piece 31 and central magnet 33 can be fixed to each other by adhesion. The edge pieces 32 are located on the sides of the two edge magnets 34 facing away from the lower pole piece 35, and similarly, the edge pieces 32 may be fixed to the edge magnets 34 by means of adhesion. In a specific implementation, the side plate 32 is substantially in a frame-shaped structure, the side plate 32 is disposed around the central plate 31, a second gap 38 is formed between the side plate 32 and the central plate 31, and the second gap 38 is communicated with the first gap 36. On the inner side of the side pole piece 32 facing the central pole piece 31, the side pole piece 32 is provided with a first notch 321 and a second notch 322 at positions corresponding to the two communication spaces 37, so as to communicate the communication spaces 37 with the outside of the magnetic circuit assembly 30 in the positive direction of the z-axis, and increase the size of the communication spaces 37 in the direction of the z-axis.

The lower pole piece 35 may be notched at positions corresponding to the two communication spaces 37, namely, a third notch 351 and a fourth notch 352, and the third notch 352 and the fourth notch 352 may communicate the respective communication spaces 37 with the outside of the magnetic circuit assembly 30 in the negative z-axis direction, thereby increasing the size of the communication spaces 37 in the z-axis direction.

Referring to fig. 8 to 10 together, fig. 9 isbase:Sub>A partial structural schematic view of the electroacoustic transducer shown in fig. 4, and fig. 10 isbase:Sub>A sectional view of the electroacoustic transducer shown in fig. 4 inbase:Sub>A directionbase:Sub>A-base:Sub>A. After the vibration module 20, the frame 10 and the magnetic circuit module 30 are assembled, the periphery of the acoustic membrane 21 is fixed to the first surface of the frame 10, for example, the second fixing portion 211 of the acoustic membrane 21 may be fixed to the frame 10 by adhesion. The vibration direction of the acoustic membrane 21 is parallel to the thickness direction z of the electroacoustic transducer 510. The voice coil 23 is located inside the frame 10, and one end of the voice coil 23 is fixedly connected to the diaphragm 21. Illustratively, the voice coil 23 is fixedly connected to the first fixing portion 213 of the diaphragm 21 through the connection frame 22.

The center magnet 33 and the two side magnets 34 are fixed to the lower pole piece 35 on the side facing the frame 10, one side magnet 34a is disposed around the first corner a of the center magnet 33, and the other side magnet 34B is disposed around the second corner B of the center magnet 33. An end portion of the voice coil 23 remote from the diaphragm 21 is inserted into a first gap 36 formed between the center magnet 33 and the side magnet 34.

The edge of one surface of the side pole piece 32 facing the sound film 21 is fixedly connected with the second surface of the frame 10, and the surface of the side pole piece 32 opposite to the sound film 21 is fixedly connected with the two side magnets 34. The center pole piece 31 is located inside the side pole piece 32, and the center pole piece 31 is fixed to a surface of the center magnet 33 facing the diaphragm 21. In the negative z-axis direction, the end of the voice coil 23 away from the diaphragm 21 is inserted into the second gap 38 and the first gap 36 in this order.

The two flexible circuit boards 24 are located on the side of the side pole piece 32 facing away from the frame 10, and the two flexible circuit boards 24 are respectively arranged near two corners of the voice coil 23 which are diagonally arranged. Illustratively, the first connecting portion 241 of the flexible circuit board 24a is fixedly connected to one end of the outer peripheral surface of the third corner C1 of the voice coil 23, which is far away from the diaphragm 21, and the third connecting portion 243 of the flexible circuit board 24a is fixedly connected to an edge of one surface of the side pole piece 32, which is far away from the frame 10. The first connecting portion 241 of the flexible circuit board 24b is fixedly connected to one end of the outer peripheral surface of the fourth corner D1 of the voice coil 23, which is far away from the voice diaphragm 21, and the third connecting portion 243 of the flexible circuit board 24b is fixedly connected to the edge of one surface of the side pole piece 32, which is far away from the frame 10. On the side of the side plate 32 facing the frame 10, the first notch 321 of the side plate 32 may expose the first connection portion 241 and the second connection portion 242 of the flexible circuit board 24a, and the second notch 322 of the side plate 32 may expose the first connection portion 241 and the second connection portion 242 of the flexible circuit board 24 b. That is, in the xy plane, the two side magnets 34 are approximately in a staggered relationship with the two flexible circuit boards 24, the two side magnets 34 occupy the outer peripheral side regions of one pair of corners (i.e., the first corner A1 and the second corner B1 of the voice coil) of the voice coil 23, and the two flexible circuit boards 24 occupy the outer peripheral side regions of the other pair of corners (i.e., the third corner C1 and the fourth corner D1 of the voice coil) of the voice coil 23.

In the above-described embodiment, the voice coil 23 is provided around the outer periphery of the center magnet 33, and the first corner A1, the second corner B1, the third corner C1, and the fourth corner D1 of the voice coil 23 correspond to the first corner a, the second corner B, the third corner C, and the fourth corner D of the center magnet 33, respectively.

The two auxiliary diaphragms 25 are respectively fixed on the surfaces of the two flexible circuit boards 24, which are away from the side pole pieces 32, the first fixing portions 251 of the auxiliary diaphragms 25 are fixedly connected with the first connecting portions 241 of the corresponding flexible circuit boards 24, the second fixing portions 253 are fixedly connected with the third connecting portions 243 of the corresponding flexible circuit boards 24, and the vibrating portions 252 of the auxiliary diaphragms 25 are opposite to the second connecting portions 242 of the corresponding flexible circuit boards 24. At this time, the two auxiliary diaphragms 25 are respectively located in the two communicating spaces 37 of the magnetic circuit assembly 30.

In addition, in the present embodiment, the flexible circuit board 24 and the side magnet 34 may have an overlapping region in the z-axis direction, so as to increase the length of the flexible circuit board 24 while ensuring that the side magnet 34 has a larger size, thereby improving the magnetic induction of the magnetic circuit assembly 30 and the vibration performance of the vibration assembly. In specific implementation, the straight line segment of the second connection portion 242 of the flexible circuit board 24a exceeds the straight line segment of the first connection portion 241 along the y-axis negative direction, that is, the tail end of the second connection portion 242 is disposed closer to the first corner A1 of the voice coil 23 relative to the head end of the first connection portion 241. Outside the first side surface 331 of the central magnet 33, a first avoiding groove 343 is formed in one surface of the first branch 341 facing the side pole piece 32, and a distal end portion of the second connecting portion 242 of the flexible circuit board 24a may extend above the first branch 341 and be disposed opposite to the first avoiding groove 343. In addition, a first avoiding hole 323 is formed in the position of the side pole piece 32 corresponding to the first avoiding groove 343, and the first avoiding hole 323 is communicated with the first notch 321. Thus, when the voice coil 23 drives the flexible circuit board 24a to vibrate along the z-direction, the first avoiding groove 343 and the first avoiding hole 323 can provide an avoiding space for the movement of the second connecting portion 242, so as to avoid the interference of the first branch 341 and the edge piece 32 on the movement of the second connecting portion 242, and improve the vibration performance of the vibration assembly 30.

Similarly, the straight line segment of the second connection portion 242 of the flexible circuit board 24B exceeds the straight line segment of the first connection portion 241 in the positive y-axis direction, that is, the tip end of the second connection portion 242 is disposed closer to the second corner B1 of the voice coil than the head end of the first connection portion 241. A second avoiding groove 344 is formed in one surface of the first branch 341 facing the side pole piece 32 outside the third side surface 333 of the central magnet 33, and an end portion 242 of the second connection portion of the flexible circuit board 24b may extend above the first branch 341 and be opposite to the second avoiding groove 344. A second avoiding hole 324 is formed in the position of the side pole piece 32 corresponding to the second avoiding groove 344, and the second avoiding hole 324 is communicated with the second notch 322. Thus, when the voice coil 23 drives the flexible circuit board 24b to vibrate along the z-direction, the second avoiding groove 344 and the second avoiding hole 324 can provide an avoiding space for the movement of the second connecting portion 242, so as to avoid the interference of the first branch 341 and the edge piece 32 on the movement of the second connecting portion 242, and improve the vibration performance of the vibration assembly 30.

It should be noted that, in order to reduce the difficulty of the manufacturing process of the edge magnet 34, in some embodiments, the portion of the first branch 341 with the first avoiding groove 343 (the third avoiding groove 344) and the rest of the edge magnet 34 may be formed separately and then fixedly connected by bonding or the like.

Referring also to fig. 11, fig. 11 is a cross-sectional view of the electro-acoustic transducer shown in fig. 4, taken in the direction B-B. Illustratively, one end of the central magnet 33 close to the central pole piece 31 is an N pole, and one end close to the lower pole piece 35 is an S pole; the side magnet 34 has an S-pole at the end near the side pole piece 32 and an N-pole at the end near the lower pole piece 35. The path of the magnetic flux lines (shown by the dotted line in fig. 11) is "the N-pole of the center magnet 33, the center pole piece 31, the second gap 38, the side pole piece 32, the S-pole of the side magnet 34, the N-pole of the side magnet 34, the lower pole piece 35, and the S-pole of the center magnet 33". Since the voice coil 23 is partially located in the second gap 38, and the magnetic circuit assembly forms a magnetic field in the second gap 36, when the voice coil 23 is energized, an ampere force in the z-axis direction is generated, thereby driving the voice coil 23 and the diaphragm 21 connected to the voice coil 23 to vibrate. The sound film 21 pushes the air in front of the sound film (i.e. in the positive direction of the z-axis) to form sound waves when vibrating, so that the electroacoustic transducer 510 generates sound.

When the voice coil 23 vibrates, the first connection portion 241 and the second connection portion 242 of the flexible circuit board 24a vibrate in the z-axis direction in the first notch 321 and the corresponding communication space 37, and the amplitude gradually decreases from the head end of the first connection portion 241 to the tail end of the second connection portion 242; the third connecting portion 243 of the flexible circuit board 24a is fixed to the edge of the side pole piece 32 and does not vibrate with the voice coil 23; the auxiliary diaphragm 25 vibrates in the z-axis direction in the communicating space 37 below the first notch 321. The first connection portion 241 and the second connection portion 242 of the flexible circuit board 24b vibrate along the z-axis direction in the second notch 322 and the corresponding communication space 37, and the amplitude gradually decreases from the head end of the first connection portion 241 to the tail end of the second connection portion 242; the third connecting portion 243 of the flexible circuit board 24b is fixed to the edge of the side pole piece 32 and does not vibrate with the voice coil 23; the auxiliary diaphragm 25 vibrates in the z-axis direction in the communicating space 37 below the second notch 322.

In the present embodiment, the sound film 21 located above the voice coil 23 may be formed as a first compliant system of the electroacoustic transducer 510, and the flexible circuit board 24 and the auxiliary diaphragm 25 located below the voice coil 23 may be formed as a second compliant system of the electroacoustic transducer 510, so that when the two compliant systems vibrate with the voice coil 23, rolling vibration of the voice coil 23 can be suppressed, which is helpful for obtaining better sound quality of the electroacoustic transducer 510. The compliance coefficient of the compliance system is the reciprocal of the elastic coefficient, and the parts with higher compliance coefficients are more prone to deformation when stressed.

In two compliance systems, the sound film 21 is harder and less compliant, so that the sound film 21 can smoothly push air to make sound; the flexible circuit board 24 and the auxiliary diaphragm 25 have small hardness and high compliance, so that the total hardness of the two compliance systems is proper, thereby ensuring the operational reliability of the electroacoustic transducer 510. In addition, in the specific design, the hardness of the auxiliary diaphragm 25 may be greater than that of the flexible circuit board 24, so that the stability of the second compliance system may be better, and thus the sway of the voice coil 23 may be better suppressed, and the rolling amplitude of the voice coil 23 may be reduced.

Compare in the traditional electroacoustic transducer who arranges limit magnet in the side of central magnet, the electroacoustic transducer of this embodiment makes two limit magnets be two bight settings of diagonal arrangement around central magnet respectively through designing limit magnet for L type structure to the magnet of two bight periphery sides is lacked, makes the whole size of limit magnet can increase 20% at least, consequently can effectively improve magnetic circuit assembly's magnetic induction intensity, and then promotes magnetic circuit assembly's driving force, makes electroacoustic transducer have better sensitivity. Proved by verification, the sensitivity of the electroacoustic transducer provided by the embodiment can be improved by more than 1 dB.

The above description is only for the specific embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily think of the changes or substitutions within the technical scope of the present application, and shall be covered by the scope of the present application. Therefore, the protection scope of the present application shall be subject to the protection scope of the claims.

Claims (14)

1. The utility model provides an electroacoustic transducer which characterized in that, includes central magnet, two limit magnets, lower pole piece, limit pole piece, frame, sound membrane, voice coil loudspeaker voice coil and two flexible circuit board, wherein:

the central magnet and the two side magnets are respectively arranged on one surface of the lower pole piece; the central magnet is of a rectangular structure and comprises a first corner and a second corner which are arranged diagonally; the two side magnets are arranged around the first corner and the second corner in a centrosymmetric manner respectively, and a first gap is formed between each side magnet and the corresponding central magnet;

the side pole pieces are arranged on one surfaces of the two side magnets, which are opposite to the lower pole piece;

one surface of the frame is fixedly connected with one surface of the side pole piece, which is back to the lower pole piece, and the other surface of the frame is fixedly connected with the periphery of the sound film;

the voice coil is positioned on the inner side of the frame and is of a rectangular annular structure, one end of the voice coil is fixedly connected with the voice film, and the other end of the voice coil is inserted into the first gap;

two the flexible circuit board symmetric distribution in week side of voice coil loudspeaker voice coil, just flexible circuit board's one end with voice coil loudspeaker voice coil fixed connection, the other end and limit pole piece fixed connection.

2. The electro-acoustic transducer of claim 1, wherein the central magnet includes first and second sides adjacent the first corner, and third and fourth sides adjacent the second corner;

the side magnets comprise a first branch and a second branch which are connected into an L-shaped structure, wherein the first branch and the second branch of one side magnet are respectively positioned at the outer sides of the first side surface and the second side surface, and the first branch and the second branch of the other side magnet are respectively positioned at the outer sides of the third side surface and the fourth side surface.

3. The electro-acoustic transducer of claim 2, wherein the central magnet further comprises diagonally disposed third and fourth corners;

wherein the first branch of one of the side magnets extends to between the first corner and the third corner, and the second branch extends to an end of the second side surface near the fourth corner; the first branch of the other side magnet extends to the position between the second corner and the fourth corner, and the second branch extends to the end, close to the third corner, of the fourth side face.

4. The electro-acoustic transducer of claim 3, wherein the voice coil includes third and fourth corners corresponding to the third and fourth corners, respectively;

the two flexible circuit boards are respectively arranged on the outer peripheral sides of the third corner and the fourth corner, one end of each flexible circuit board is fixedly connected with the voice coil, and the other end of each flexible circuit board is fixedly connected with one surface, facing the lower pole piece, of the side pole piece.

5. The electro-acoustic transducer of claim 4, wherein the flexible circuit board comprises a first connecting portion, a second connecting portion and a third connecting portion, which are connected in sequence, the first connecting portion is fixedly connected with the voice coil, the second connecting portion is located on a side of the first connecting portion away from the voice coil, the third connecting portion is located on a side of the second connecting portion away from the first connecting portion, and the third connecting portion is fixedly connected with the side pole piece;

the side pole piece is provided with a first notch and a second notch which are symmetrically distributed, and the first notch and the second notch are respectively exposed out of the first connecting part and the second connecting part of the flexible circuit board.

6. The electro-acoustic transducer according to claim 5, wherein an end of the second connection portion connected to the third connection portion overlaps a surface of the first branch facing away from the lower pole piece, on an outer peripheral side of the first side surface and an outer peripheral side of the third side surface, and an avoiding groove is formed in a position of the first branch corresponding to an end of the second connection portion.

7. The electroacoustic transducer of claim 6 wherein the side pole piece is provided with an avoiding hole at a position corresponding to the two avoiding grooves, and the two avoiding holes are respectively communicated with the first notch and the second notch.

8. The electroacoustic transducer of any one of claims 5 to 7, further comprising two auxiliary diaphragms, wherein the two auxiliary diaphragms are respectively disposed on sides of the two flexible circuit boards facing away from the sound film, one end of each auxiliary diaphragm is fixedly connected to the corresponding first connecting portion of the flexible circuit board, and the other end of each auxiliary diaphragm is fixedly connected to the corresponding third connecting portion of the flexible circuit board.

9. The electro-acoustic transducer of claim 8, wherein the diaphragm includes a vibrating portion, the cross-sectional shape of the vibrating portion of the diaphragm is arc-shaped, and the vibrating portion of the diaphragm is convex away from the lower pole piece;

the auxiliary vibrating diaphragm comprises a vibrating portion, the cross section of the vibrating portion of the auxiliary vibrating diaphragm is arc-shaped, and the vibrating portion of the auxiliary vibrating diaphragm faces the direction of the lower pole piece in a protruding mode.

10. The electro-acoustic transducer of claim 8, wherein the lower pole piece is provided with a third gap and a fourth gap at positions corresponding to the two auxiliary diaphragms, respectively.

11. The electro-acoustic transducer of any one of claims 1 to 7, further comprising a connection frame, wherein the connection frame is located between the voice coil and the diaphragm, and one end of the connection frame is fixedly connected to the voice coil and the other end is fixedly connected to the diaphragm.

12. A speaker module comprising a case and the electroacoustic transducer of any of claims 1 to 11, wherein the electroacoustic transducer is disposed in the case, and the case is provided with a sound outlet.

13. An electronic device, comprising a housing and the speaker module as claimed in claim 12, wherein the speaker module is disposed in the housing, and the housing is provided with a speaker hole, and the speaker hole communicates the sound outlet hole with the outside of the electronic device.

14. An electronic device, comprising a housing, a display module, and a receiver, wherein the receiver is disposed in the housing, and the receiver is the electroacoustic transducer of any one of claims 1 to 11;

the display module comprises a glass cover plate and a display panel, the glass cover plate is fixed on the shell, and the display panel is fixed on the inner surface, facing the shell, of the glass cover plate;

the cover plate is provided with a telephone receiving hole, or a telephone receiving hole is formed between the edge of the cover plate and the shell, or the shell is provided with a telephone receiving hole;

the sound emitted by the telephone receiver can be transmitted to the outside of the electronic equipment through the telephone receiver.

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