CN112088538B

CN112088538B - Electroacoustic transducer and communication device

Info

Publication number: CN112088538B
Application number: CN201880093305.8A
Authority: CN
Inventors: 刘金华; 于利刚; 单海波
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2018-05-14
Filing date: 2018-05-14
Publication date: 2022-02-25
Anticipated expiration: 2038-05-14
Also published as: CN112088538A; WO2019218117A1

Abstract

An electroacoustic transducer has a channel communicating an inboard back cavity with a back cavity channel. The channel includes an edge channel and a corner channel, the edge channel being disposed between the voice coil and the plurality of sides. The angle channel is arranged between the voice coil and the angle part, and the width of the angle channel is greater than that of the side channel; or, the corner channel is arranged between the voice coil and the corner part and in the corner part, the part of the corner channel between the voice coil and the corner part has a first width, the part of the corner channel in the corner part has a second width, and the sum of the first width and the second width is larger than the width of the side channel. The electroacoustic transducer described above has a suitable damping. The application also discloses a communication device.

Description

Electroacoustic transducer and communication device

Technical Field

The present application relates to the field of electronic products, and in particular, to an electroacoustic transducer and a communication device using the electroacoustic transducer.

Background

With the development of science and technology, the 3G, 4G, and 5G communication technologies have advanced, and the mobile multimedia technology has developed, the usage rate of devices related to audio functions is higher and higher, and many audio-related devices have various entertainment functions, such as video playing, digital camera shooting, games, Global Positioning System (GPS) navigation, and the like, and the audio devices are required to have good audio playing performance and more precise and compact spatial structures.

In audio-related devices, it is usually necessary to provide a miniature electroacoustic transducer for playing audio signals, wherein the miniature electroacoustic transducer most commonly used is a moving-coil miniature loudspeaker.

The small size and high volume are the application requirements and technical directions of miniature electroacoustic transducers. With the development of assembly technology, the magnetic gap of the electroacoustic transducer is becoming smaller and smaller to obtain higher magnetic induction (i.e. B value) to improve the sensitivity of the electroacoustic transducer. Too small a magnetic gap, however, tends to result in excessive damping, which reduces the sensitivity of the electro-acoustic transducer near the resonant frequency (Fo), reduces the transduction efficiency, and also causes signal distortion.

Disclosure of Invention

The application provides an electroacoustic transducer with proper damping and a communication device applying the electroacoustic transducer.

In a first aspect, the present application provides an electroacoustic transducer. The electroacoustic transducer is applicable to communication devices. The electroacoustic transducer may comprise a micro speaker and a micro receiver. The electroacoustic transducer comprises a lower pole piece, a central magnet, a side magnet group, an upper central pole piece, an upper pole piece, a vibrating diaphragm and a voice coil. The central magnet is arranged on the lower pole piece.

The side magnet group is arranged on the lower pole piece and surrounds the central magnet, and a rear cavity channel is formed between the side magnet group and the central magnet. The upper central pole piece is arranged on one side of the central magnet, which deviates from the lower pole piece. The upper pole piece is arranged on one side, far away from the lower pole piece, of the edge magnet group.

The voice coil is located between the upper edge pole piece and the upper center pole piece. The voice coil is fixedly connected with the vibrating diaphragm. The vibrating diaphragm is located go up the central pole piece and deviate from one side of central magnet, just the vibrating diaphragm, the voice coil loudspeaker voice coil reaches form inboard back chamber between the central pole piece.

The upper central pole piece comprises a plurality of side faces and corner portions connected between the adjacent side faces. A channel is arranged between the inner rear cavity and the rear cavity channel. The channel includes an edge channel and a corner channel, the edge channel is located between the voice coil and the plurality of sides.

The corner channel is arranged between the voice coil and the corner part, and the width of the corner channel is greater than that of the side channel;

or, the corner channel is arranged between the voice coil and the corner part and in the corner part, the corner channel between the voice coil and the corner part has a first width, the corner channel in the corner part has a second width, and the sum of the first width and the second width is larger than the width of the side channel.

In this application, the width of the corner channel of the channel is greater than the width of the side channel, or the width of two parts of the corner channel and greater than the width of the side channel, so that the overall flow area of the channel is increased, that is, the area of the internal magnetic gap is increased, when the diaphragm is driven by the voice coil to vibrate, the airflow can more rapidly flow between the internal back cavity and the back cavity channel, so that the damping of the electroacoustic transducer can be reduced, the Q value (also called quality factor) of the electroacoustic transducer is improved, the sensitivity of the electroacoustic transducer in a frequency band near Fo (resonance frequency) is higher, the loudness is higher, the distortion of the frequency band near Fo can also be reduced, and a better sound quality effect is obtained.

And an outer rear cavity is formed among the diaphragm, the voice coil and the upper pole piece. An outer magnetic gap is formed between the voice coil and the upper pole piece. The outer magnetic gap is communicated with the outer rear cavity and the rear cavity channel.

The voice coil comprises a plurality of straight line parts and arc line parts connected between the adjacent straight line parts. The arc line is positioned at four corners of the voice coil. The outer magnetic gaps comprise edge outer magnetic gaps and angle outer magnetic gaps. The off-edge magnetic gap is positioned between the linear part and the upper edge pole piece. The corner outer magnetic gap is located between the arc portion and the upper pole piece. The edge outer magnetic gaps and the corner outer magnetic gaps are communicated with each other.

Based on the structural design requirements of the electroacoustic transducer, the width of the corner outer magnetic gap is larger than that of the edge outer magnetic gap. The electromagnetic transducer has a large width of the angular outer magnetic gap, so that the magnetic induction intensity of the magnetic circuit part corresponding to the angular outer magnetic gap is low. Because the corner channels and the corner external magnetic gaps of the channels are respectively arranged at two sides of four corners of the voice coil, the width of the corner channels is increased, and when the width of the corner channels is larger than that of the side channels, the whole magnetic induction intensity of a magnetic circuit part of the electroacoustic transducer cannot be obviously influenced. In short, the electroacoustic transducer reduces the damping of the electroacoustic transducer to a proper range by increasing the width of the angular channel under the condition of not weakening or hardly weakening the whole magnetic induction intensity of the electroacoustic transducer, thereby improving the Q value of the electroacoustic transducer and improving the sensitivity of the electroacoustic transducer in a frequency band near Fo.

In one embodiment, the medial posterior chamber forms a first projection on the lower pole piece. The channel forms a second projection on the lower pole piece. The ratio of the area of the second projection to the area of the first projection is greater than or equal to 4.5%.

In this embodiment, since the vibration direction of the voice coil is perpendicular to the lower pole piece, the area of the first projection may be substantially equal to the radiation area of the center portion of the voice coil (i.e., the area of the air pushed by the portion of the diaphragm located inside the voice coil), and the area of the second projection may be substantially equal to the cross-sectional area through which the air flows between the inner rear cavity and the rear cavity channel. When the ratio of the area of the second projection to the area of the first projection is greater than or equal to 4.5%, the electroacoustic transducer can meet the requirements of damping and magnetic induction intensity, so that the overall performance of the electroacoustic transducer is better.

In one embodiment, when the corner channel is provided between the voice coil and the corner portion, the corner portion includes an outer flat surface connected between two adjacent side surfaces. The outer flat surface may be formed by chamfering between adjacent two of the side surfaces.

In one embodiment, the corner comprises a recessed area recessed from the outer plane towards the inside of the corner. The provision of the recessed region enables the width of the corner channel to be further increased.

In one embodiment, the voice coil includes a curved portion facing the corner portion. When the corner channel is disposed between the voice coil and the corner portion, the corner portion includes an extrados surface. The outer arc surface is connected between two adjacent planes. The outer arc surface may be formed by rounding between two adjacent side surfaces. The outer arc is convex toward a direction close to the voice coil. The radius of the outer cambered surface is larger than or equal to the radius of the cambered part.

In this embodiment, the corner channel is formed between the extrados and the voice coil, and the width of the corner channel is greater than the width of the side channel. In the circumferential direction of the voice coil, the surface of the corner portion facing the voice coil is the outer arc surface, so that the width change of the corner channel is smooth, and the vibrating diaphragm is favorable for stable vibration.

In one embodiment, the upper central pole piece forms a third projection on the lower pole piece. The central magnet forms a fourth projection on the lower pole piece. The third projection overlays the fourth projection.

In this embodiment, since the third projection covers the fourth projection, the upper central pole piece covers the central magnet, and the upper central pole piece can more effectively constrain the magnetic path to improve the magnetic induction intensity of the electroacoustic transducer.

In one embodiment, the area of the third projection is larger than the area of the fourth projection, and the contour shape of the third projection is the same as the contour shape of the fourth projection.

In this embodiment, the distance between the side surface of the upper central pole piece and the voice coil is smaller than the distance between the central magnet and the voice coil, and the upper central pole piece can more effectively constrain the magnetic path to improve the magnetic induction intensity of the electroacoustic transducer. The contour shape of the upper central pole piece is the same as that of the central magnet, so that the magnetic field arrangement of the magnetic circuit part of the electroacoustic transducer is more regular, and the vibration action of the vibrating diaphragm is more stable.

The distance between the upper pole piece and the voice coil is smaller than the distance between the side magnet group and the voice coil, so that the magnetic path is better constrained, and the magnetic induction intensity of the electroacoustic transducer is improved.

In one embodiment, when the corner channel is provided between the voice coil and the corner portion and in the corner portion, the corner portion is provided with a through hole and a side arc surface. The side arc surface is connected between the two side surfaces. And a part of the angular channel is formed between the side cambered surface and the voice coil, and the other part of the angular channel is formed in the through hole.

In other words, the corner channel comprises a first portion and a second portion. The first portion is disposed between the voice coil and the corner portion. The second portion is disposed in the corner. The first portion and the second portion both communicate the inboard rear cavity with the rear cavity channel. A portion of the angular channel between the voice coil and the corner portion (i.e., the first portion) has a first width. The first width is a dimension of the first portion in a radial direction of the voice coil. Portions of the corner channels in the corner (i.e., the second portions) have a second width. The second width is a dimension of the first portion in a radial direction of the voice coil. The sum of the first width and the second width is greater than the width of the side channel.

The side arc face and the voice coil form a part of the angular channel, namely the first part. The arrangement of the side cambered surfaces enables the width of the first part to be gradually changed, so that smooth vibration of the diaphragm is facilitated. The through hole penetrates through the upper central pole piece. The other part of the corner channel, i.e. the second part, is formed in the through hole. The through-holes may be elliptical holes, circular holes, polygonal holes, etc. For example, the through-holes are elliptical holes, so that a smaller fluid flow resistance is obtained with the same flow area.

In one embodiment, a portion of the corner channel between the side arc and the voice coil has the first width, and the first width is greater than or equal to the width of the side channel. When the first width is equal to the side channel, an internal magnetic gap formed by the first portion and the side channel is unchanged in the circumferential direction of the voice coil, so that the vibrating diaphragm vibrates stably. When the first width is larger than the width of the side channel, the flow area of the corner channel is larger, so that the Q value of the electroacoustic transducer is improved, and the damping is reduced.

In one embodiment, the central magnet is provided with four avoidance areas, and the four avoidance areas are communicated with the through holes and the rear cavity channel in a one-to-one correspondence manner. The projection of the avoiding area on the lower pole piece is partially overlapped with the projection of the angle channel on the lower pole piece. The shape of the projection of the central magnet on the lower pole piece is different from the shape of the projection of the angular channel on the upper central pole piece. Because the central magnet is manufactured by sintering, the avoiding area of the central magnet is difficult to process into a complex shape, and the surface of the central magnet contacting the avoiding area can be a plane or a cambered surface. Of course, the surface of the central magnet contacting the avoiding region may have a different shape, or the central magnet may have the same contour shape as the upper central pole piece (referring to the projection shape on the lower pole piece), if the manufacturing process allows.

In one embodiment, an external magnetic gap is formed between the voice coil and the upper pole piece. The outer magnetic gaps comprise a first angle outer magnetic gap and a second angle outer magnetic gap. The angular channels include a first angular channel and a second angular channel. The first corner external magnetic gap and the first corner channel are respectively arranged on two sides of the same part of the voice coil. The second corner external magnetic gap and the second corner channel are respectively arranged on two sides of the same part of the voice coil. The width of the first corner external magnetic gap is larger than that of the second corner external magnetic gap. The width of the first corner external magnetic gap is used for meeting the structural design requirement of the electroacoustic transducer. The width of the second corner external magnetic gap is larger than that of the side external magnetic gap, and the second corner external magnetic gap is used for balancing with the first corner external magnetic gap so that the vibration action of the vibrating diaphragm is stable. The width of the first angular channel is smaller than the width of the second angular channel.

In this embodiment, since the width of the first corner outer magnetic gap is greater than the width of the second corner outer magnetic gap, and the width of the first corner channel is less than the width of the second corner channel, the sum of the areas of the corner channels corresponding to the corners of the voice coil and the area of the outer magnetic gap is similar, so that the vibration motion of the diaphragm is more balanced and stable.

In one embodiment, the electroacoustic transducer further comprises a lead wire, the lead wire comprising a connection end and a pigtail end. The connecting end is connected with the voice coil. The leading-out terminal is used for connecting an external circuit. The connecting end is contained in the first corner external magnetic gap. Since the second corner external magnetic gap is not required to avoid the connection end of the lead, the width of the second corner external magnetic gap may be smaller than the width of the first corner external magnetic gap.

In this embodiment, the first angular outer magnetic gap has a large width, so that the lead-out terminal can be accommodated in the first outer magnetic gap and can vibrate in the first outer magnetic gap along with the voice coil.

In a second aspect, the present application provides a communication device comprising the electroacoustic transducer described above. The communication device referred to in the present application may be any device having communication and storage functions, for example: the system comprises intelligent equipment with a network function, such as a tablet personal computer, a mobile phone, an electronic reader, a remote controller, a personal computer, a notebook computer, vehicle-mounted equipment, a network television, wearable equipment and the like. The electroacoustic transducer has higher Q value and proper damping, and has higher sensitivity and loudness in a frequency band near Fo, so the communication equipment applying the electroacoustic transducer has a better broadcasting function.

Drawings

Fig. 1 is a schematic structural diagram of a communication device according to an embodiment of the present disclosure;

fig. 2 is a schematic structural diagram of an electroacoustic transducer provided in an embodiment of the present application;

FIG. 3 is a schematic view of the electro-acoustic transducer of FIG. 2 at another angle;

FIG. 4 is an exploded view of one embodiment of the electro-acoustic transducer of FIG. 2;

FIG. 5 is a schematic view of the electro-acoustic transducer of FIG. 2 taken along line A-A;

FIG. 6 is a schematic view of the electro-acoustic transducer of FIG. 3 taken along line B-B;

FIG. 7 is a top view of one embodiment of the electroacoustic transducer of FIG. 2 with the diaphragm hidden;

FIG. 8 is a schematic view of the circumferential and radial directions of the voice coil of FIG. 7;

FIG. 9 is a graph comparing the sensitivity curve of the electro-acoustic transducer shown in FIG. 2 with the sensitivity curve of a conventional electro-acoustic transducer;

FIG. 10 is a schematic view of the projection of the inner rear cavity and channel of the electro-acoustic transducer of FIG. 4 onto the lower pole piece;

FIG. 11 is a schematic view of the projection relationship of the upper central pole piece and the central magnet of the electro-acoustic transducer of FIG. 4 onto the lower pole piece;

FIG. 12 is a top view of another embodiment of the electroacoustic transducer of FIG. 2 with the diaphragm hidden;

FIG. 13 is a top view of yet another embodiment of the electroacoustic transducer of FIG. 2 with the diaphragm hidden;

FIG. 14 is a top view of yet another embodiment of the electroacoustic transducer of FIG. 2 with the diaphragm hidden;

FIG. 15 is a top view of yet another embodiment of the electroacoustic transducer of FIG. 2 with the diaphragm hidden;

FIG. 16 is a schematic diagram of the electro-acoustic transducer of FIG. 2 configured along line C-C in one embodiment;

fig. 17 is a schematic view showing a positional relationship between the upper center pole piece and the center magnet shown in fig. 16.

Detailed Description

The following description will be made with reference to the drawings in the embodiments of the present application.

Referring to fig. 1, fig. 1 is a schematic structural diagram of a communication device 100 according to an embodiment of the present disclosure. The communication device 100 according to the embodiment of the present application may be any device having communication and storage functions, for example: the system comprises intelligent equipment with a network function, such as a tablet Computer, a mobile phone, an electronic reader, a remote controller, a Personal Computer (PC), a notebook Computer, vehicle-mounted equipment, a network television, wearable equipment and the like. In the present embodiment, the communication device 100 is a mobile phone as an example.

The communication device 100 includes an electroacoustic transducer. The electroacoustic transducers may include a micro-speaker (also called a horn) 201 and a micro-receiver (also called an earpiece) 202. The communication device 100 further comprises a front cover 101 and a housing 102. The front cover 101 includes a cover plate 1011 and a display screen 1012 fixed to the cover plate 1011. The front cover 101 is fixed to the housing 102, the front cover and the housing together enclose an inner cavity of the whole device, and the micro speaker 201 and the micro receiver 202 are accommodated in the inner cavity of the whole device. The front cover 101 is provided with a sound outlet 1013, and the sound of the miniature telephone receiver 202 is transmitted through the sound outlet 1013. The housing 102 is provided with a sound outlet hole 1021, and sound emitted from the micro-speaker 201 is transmitted through the sound outlet hole 1021.

Referring to fig. 2 and fig. 3 together, fig. 2 is a schematic structural diagram of an electroacoustic transducer 200 according to an embodiment of the present disclosure, and fig. 3 is a schematic structural diagram of the electroacoustic transducer 200 shown in fig. 2 at another angle. The electroacoustic transducer 200 comprises a frame 1, a magnetic circuit part 2 and a diaphragm 3. The magnetic circuit part 2 is fixed on the bottom side of the basin stand 1, and the vibrating diaphragm 3 is fixed on the top side of the basin stand 1.

Referring also to fig. 4, fig. 4 is an exploded view of one embodiment of the electro-acoustic transducer 200 of fig. 2. The magnetic circuit part 2 comprises a lower pole piece 21, a central magnet 22, a side magnet group 23, an upper central pole piece 24 and an upper pole piece 25. The side magnet group 23 includes a plurality of side magnets 231, and the plurality of side magnets 231 are spaced apart from each other. The electroacoustic transducer 200 further comprises a voice coil 4. The voice coil 4 is located on the side of the diaphragm 3 facing the magnetic circuit portion 2. In the electroacoustic transducer 200, the magnetic circuit portion 2 and the diaphragm 3 are respectively fixed on opposite sides of the frame 1, and the voice coil 4 is located inside the frame 1.

Referring to fig. 5 and 6 together, fig. 5 is a schematic view of the electroacoustic transducer 200 shown in fig. 2 along the line a-a, and fig. 6 is a schematic view of the electroacoustic transducer shown in fig. 3 along the line B-B. The structure shown in fig. 6 corresponds to the same embodiment of the electroacoustic transducer 200 as that shown in fig. 4.

The central magnet 22 is disposed on the lower pole piece 21. The side magnet group 23 is disposed on the lower pole piece 21 and surrounds the central magnet 22. A back cavity channel 210 is formed between the side magnet group 23 and the central magnet 22. A gap 220 is formed between adjacent side magnets 231 in the side magnet group 23, and the gap 220 communicates the rear cavity channel 210 to the space outside the electroacoustic transducer 200.

Referring to fig. 5, the upper central pole piece 24 is disposed on a side of the central magnet 22 away from the lower pole piece 21. The upper pole piece 25 is arranged on one side of the side magnet group 23 far away from the lower pole piece 21. A gap is formed between the upper pole piece 25 and the upper central pole piece 24.

The voice coil 4 is located between the upper pole piece 25 and the upper central pole piece 24. The voice coil 4 is fixedly connected with the diaphragm 3. The voice coil 4 vibrates together with the diaphragm 3. The upper central pole piece 24 includes two sides that are opposite each other, one of the sides faces the central magnet 22, and the other side faces away from the central magnet 22. The diaphragm 3 is located on one side of the upper central pole piece 24 departing from the central magnet 22, and an inner rear cavity 230 is formed among the diaphragm 3, the voice coil 4 and the upper central pole piece 24.

Referring to fig. 5 and 7 together, fig. 7 is a top view of an embodiment of the electroacoustic transducer 200 shown in fig. 2 when the diaphragm 3 is hidden. The structure shown in fig. 7 corresponds to the same embodiment of the electroacoustic transducer 200 as that shown in fig. 4.

The upper central pole piece 24 includes a plurality of side surfaces 241 and corner portions 242 connected between adjacent side surfaces 241. A channel 240 is provided between the medial posterior chamber 230 and the posterior chamber channel 210. The channels 240 include side channels 2401 and corner channels 2402. The side passages 2401 and the corner passages 2402 communicate with each other. The side channel 2401 is disposed between the voice coil 4 and the plurality of side surfaces 241. The width W1 of the side channel 2401 is small, and the distance between the voice coil 4 and the plurality of side surfaces 241 of the upper central pole piece 24 is small, so that the requirement of the electroacoustic transducer 200 on magnetic induction intensity can be met, and the miniaturization of the electroacoustic transducer 200 is facilitated. The corner channel 2402 is provided between the voice coil 4 and the corner 242. For example, the corner 242 includes an outer plane 2421, and the outer plane 2421 is connected between two adjacent side surfaces 241. The outer flat surface 2421 may be formed by chamfering between two adjacent side surfaces 241. The outer flat surface 2421 and the voice coil 4 form the angular channel 2402 therebetween. The width W2 of the corner channel 2402 is greater than the width W1 of the side channel 2401. In this embodiment, the channel 240 formed by the corner channel 2402 and the side channel 2401 is commonly referred to as an internal magnetic gap. The inner magnetic gap in the present embodiment is not uniform in size.

It will be understood that, referring to fig. 7 and 8 together, fig. 8 is a schematic view of the circumferential direction and the radial direction of the voice coil in fig. 7. In the present application, the voice coil 4 has a circumferential direction X (shown by a dotted line) and a radial direction Y (shown by a solid line) perpendicular to the circumferential direction X. The circumferential direction X of the voice coil 4 is the winding direction of the wire running in the voice coil 4. The voice coil 4 is wound around the center magnet 22 in the circumferential direction X. The "width W1 of the side passage 2401" referred to in the present application is a dimension of the side passage 2401 in the radial direction Y of the voice coil 4. "the width W2 of the angular passage 2402" is a dimension of the angular passage 2402 in the radial direction Y of the voice coil 4.

With continued reference to fig. 4 and 5, the diaphragm 3 includes a spherical top 31 and a corrugated portion 32 disposed around the spherical top 31. The edge of the bending ring part 32 far away from the top part 31 of the ball is fixed on the basin frame 1, so that the diaphragm 3 is positioned above the upper central pole piece 24 and the upper pole piece 25 and is arranged at an interval with the upper central pole piece 24 and the upper pole piece 25. The voice coil 4 is fixed to the edge of the globe top 31 near the hinge portion 32. The ball top 31 is located above the upper central pole piece 24, and the ball top 31, the voice coil 4 and the central pole piece form the inner rear cavity 230 therebetween. The hinge portion 32 is located above the upper pole piece 25. An outer rear cavity 250 is formed among the bent ring part 32, the voice coil 4 and the upper pole piece 25. An outer magnetic gap 260 is formed between the voice coil 4 and the upper pole piece 25. The outer magnetic gap 260 communicates the outer rear cavity 250 with the rear cavity channel 210.

With reference to fig. 7, the voice coil 4 includes a plurality of straight portions 41 and an arc portion 42 connected between adjacent straight portions 41. The arc portions 42 are located at four corners of the voice coil 4. The outer magnetic gaps 260 include edge outer magnetic gaps 2601 and corner outer magnetic gaps 2602. The outer magnetic gap 2601 is located between the straight portion 41 and the upper pole piece 25. The outer corner magnetic gap 2602 is located between the arc portion 42 and the upper pole piece 25. The edge outer magnetic gaps 2601 and the corner outer magnetic gaps 2602 communicate with each other.

The electroacoustic transducer 200 further comprises a lead 5. The lead 5 may be integrally formed with the voice coil 4. The lead 5 includes a connection terminal 51 and a lead-out terminal 52. The connection terminal 51 is connected to the voice coil 4. The terminals 52 are used for connecting an external circuit. A large area of the lead 5 can be situated on the upper pole piece 25 in a soft connection (for example by means of a soft glue connection). The connection terminal 51 is accommodated in the corner outer magnetic gap 2602. The width W4 of the off-edge magnetic gap 2601 is small to meet the requirement of the electroacoustic transducer 200 for magnetic induction intensity, which is also beneficial to the miniaturization of the electroacoustic transducer 200. Since the corner outer magnetic gap 2602 needs to escape from the lead wire 5, a width W3 (dimension in the radial direction of the voice coil 4) of the corner outer magnetic gap 2602 is larger than a width W4 (dimension in the radial direction of the voice coil 4) of the side outer magnetic gap 2601.

In the present application, the width W2 of the corner channel 2402 of the channel 240 is greater than the width W1 of the side channel 2401, so that the overall flow area of the channel 240 is increased, that is, the area of the inner magnetic gap is increased, when the diaphragm 3 is driven by the voice coil 4 to vibrate, the airflow can more rapidly flow between the inner back cavity 230 and the back cavity channel 210, so as to reduce the damping of the electroacoustic transducer 200, improve the Q value (also called quality factor) of the electroacoustic transducer 200, make the sensitivity of the electroacoustic transducer 200 in the frequency band near Fo (resonance frequency) higher, make the loudness higher, and also reduce the distortion in the frequency band near Fo, so as to obtain better sound quality effect.

As shown in fig. 9, fig. 9 is a graph of the sensitivity curve of the electro-acoustic transducer 200 shown in fig. 2 compared to the sensitivity curve of a conventional electro-acoustic transducer. In fig. 9, the abscissa represents the frequency of the electrical signal in hertz (Hz) and the ordinate represents the sound pressure level in decibels (dB).

Compared with the conventional electroacoustic transducer, the electroacoustic transducer 200 of the present application has a higher decibel in the frequency band near Fo, i.e., has a higher sensitivity.

Meanwhile, the electromagnetic transducer 200 has a large width of the corner outer magnetic gap 2602, so that the magnetic induction intensity of the magnetic circuit portion 2 corresponding to the corner outer magnetic gap 2602 is low. Since the corner channels 2402 and the corner outer magnetic gaps 2602 of the channel 240 are respectively disposed at two sides of four corners of the voice coil 4, the width W2 of the corner channels 2402 is increased, so that when the width W2 of the corner channels 2402 is greater than the width W1 of the side channels 2401, the overall magnetic induction intensity of the magnetic circuit portion 2 of the electroacoustic transducer 200 is not significantly affected. In short, the electroacoustic transducer 200 reduces the damping of the electroacoustic transducer 200 to a suitable range by increasing the width W2 of the corner channel 2402 without or with little attenuation of the overall magnetic induction, so as to increase the Q value of the electroacoustic transducer 200 and improve the sensitivity of the electroacoustic transducer 200 in the frequency band around Fo.

It is understood that in the present application, the number of the corner channels 2402 is four. The four corner channels 2402 may be identical or different in configuration. At least one of the corner channels 2402 in the electroacoustic transducer 200 satisfies the requirement that the width W2 is greater than the width W1 of the side channel 2401, which is the technical solution protected by the present application. The present application illustrates a structure (including shape and size) in which the four corner channels 2402 are identical. The number of the side channels 2401 in this application is four, and the example in which the widths W2 of the four side channels 2401 are the same is described.

Referring to fig. 5 and 10 together, fig. 10 is a schematic diagram illustrating a projection relationship between the inner rear cavity 230 and the channel 240 of the electroacoustic transducer 200 shown in fig. 4 on the lower pole piece 21. The structure shown in fig. 10 corresponds to the same embodiment of the electroacoustic transducer 200 as that shown in fig. 4.

The inner rear cavity 230 forms a first projection 230' on the lower pole piece 21. The first projection 230' is shown as the area encircled by the solid line in fig. 10. The channel 240 forms a second projection 240' on the lower pole piece 21. The second projection 240' is shown as the area between the solid and dashed lines in fig. 10. The ratio of the area of the second projection 240 'to the area of the first projection 230' is equal to or greater than 4.5%. For example, the ratio of the two may be 4.5%, 4.75%, 5%, etc.

In the present embodiment, since the vibration direction of the voice coil 4 is perpendicular to the lower pole piece 21, the area of the first projection 230 'can be substantially equal to the radiation area of the central portion of the voice coil 4 (i.e. the area of the air pushed by the portion of the diaphragm 3 located inside the voice coil 4), and the area of the second projection 240' can be substantially equal to the cross-sectional area of the air flowing between the inner rear cavity 230 and the rear cavity channel 210. When the ratio of the area of the second projection 240 'to the area of the first projection 230' is greater than or equal to 4.5%, the electroacoustic transducer 200 can meet the requirements of damping and magnetic induction, so that the overall performance of the electroacoustic transducer 200 is better.

Referring to fig. 4 and 11 together, fig. 11 is a schematic view showing a projection relationship between the upper central pole piece 24 and the central magnet 22 on the lower pole piece 21 shown in fig. 4. The upper central pole piece 24 forms a third projection 24' on the lower pole piece 21. The third projection 24' is structured as shown by the solid line in fig. 11. The central magnet 22 forms a fourth projection 22' on the lower pole piece 21. The fourth projection 22' is structured as shown in dashed lines in fig. 11. The third projection 24 'overlays the fourth projection 22'.

In the present embodiment, since the third projection 24 'covers the fourth projection 22', the upper central pole piece 24 covers the central magnet 22, and the upper central pole piece 24 can more effectively constrain the magnetic path to improve the magnetic induction of the electroacoustic transducer 200.

Referring to fig. 5 and 11, the area of the third projection 24 'is larger than the area of the fourth projection 22'. The distance between the side 241 of the upper central pole piece 24 and the voice coil 4 is smaller than the distance between the central magnet 22 and the voice coil 4, and the upper central pole piece 24 can more effectively restrain the magnetic path to improve the magnetic induction of the electro-acoustic transducer 200. The contour shape of the third projection 24 'is the same as the contour shape of the fourth projection 22'. At this time, the contour shape of the upper central pole piece 24 is the same as the contour shape of the central magnet 22, so that the magnetic field arrangement of the magnetic circuit part 2 of the electroacoustic transducer 200 is more regular, and the vibration action of the diaphragm 3 is more stable.

However, although the central magnet 22 is difficult to process into a complicated shape due to sintering, since the contour shape of the upper central pole piece 24 in the present embodiment is simple, the contour shape of the central magnet 22 may be the same as the contour shape of the upper central pole piece 24. Of course, in other embodiments, the contour shape of the central magnet 22 may be different from the contour shape of the upper central pole piece 24, and the present application is not limited thereto.

Referring to fig. 5, the distance between the upper pole piece 25 and the voice coil 4 is smaller than the distance between the side magnet assembly 23 and the voice coil 4, so as to better constrain the magnetic path and improve the magnetic induction of the electroacoustic transducer 200.

Referring to fig. 5 and 12 together, fig. 12 is a top view of another embodiment of the electroacoustic transducer 200 shown in fig. 2 when the diaphragm 3 is hidden. The electroacoustic transducer 200 of the present embodiment is different from the foregoing embodiments in that: the outer magnetic gaps 260 include a first corner outer magnetic gap 2603 and a second corner outer magnetic gap 2604. The first corner outer magnetic gaps 2603 are two in number, and the second corner outer magnetic gaps 2604 are also two in number. The width W5 of the first corner outer magnetic gap 2603 is greater than the width W4 of the edge outer magnetic gap 2601, and the connection end 51 is accommodated in the first corner outer magnetic gap 2603. The width W5 of the first corner outer magnetic gap 2603 is large, so that the lead-out terminal 52 can be accommodated in the first corner outer magnetic gap 2603 and can vibrate in the first corner outer magnetic gap 2603 along with the voice coil 4. The width W6 of the second corner outer magnetic gap 2604 is greater than the width W4 of the edge outer magnetic gap 2601, and the second corner outer magnetic gap 2604 is used for balancing with the first corner outer magnetic gap 2603, so that the vibration action of the diaphragm 3 is relatively smooth. Since the second outer corner magnetic gap 2604 is not required to avoid the connection end 51 of the lead wire 5, the width W6 of the second outer corner magnetic gap 2604 may be smaller than the width W5 of the first outer corner magnetic gap 2603.

The corner channels of the channel 240 include a first corner channel 2403 and a second corner channel 2404. The first corner outer magnetic gap 2603 and the first corner channel 2403 are respectively disposed on two sides of the same portion of the voice coil 4. The number of the first corner channels 2403 is the same as the number of the first corner external magnetic gaps 2603. The second corner outer magnetic gap 2604 and the second corner channel 2404 are respectively disposed on both sides of the same portion of the voice coil 4. The number of the second corner channels 2404 is the same as the number of the second corner outer magnetic gaps 2604. The width W5 of the first corner outer magnetic gap 2603 is greater than the width W6 of the second corner outer magnetic gap 2604, and the width W7 of the first corner channel 2403 is less than the width W8 of the second corner channel 2404.

In this embodiment, since the width W5 of the first corner outer magnetic gap 2603 is greater than the width W6 of the second corner outer magnetic gap 2604, and the width W7 of the first corner channel 2403 is smaller than the width W8 of the second corner channel 2404, the sum of the areas of the corner channels 2402 and the outer magnetic gap 260 corresponding to the corners of the voice coil 4 is similar, so that the vibration motion of the diaphragm 3 is more balanced and stable.

Of course, in other embodiments, the width W5 of the first corner outer magnetic gap 2603 may be equal to the width W6 of the second corner outer magnetic gap 2604.

Referring to fig. 13, fig. 13 is a top view of another embodiment of the electroacoustic transducer 200 shown in fig. 2, when the diaphragm 3 is hidden. The electroacoustic transducer 200 in the present embodiment is different from the foregoing embodiments in that: the corner 242 includes a recessed area 2422, and the recessed area 2422 is recessed from the outer plane 2421 towards the inside of the corner 242. The provision of the recessed area 2422 can further increase the width W2 of the corner channel 2402. The recessed area 2422 can be substantially rectangular or inverted trapezoidal (i.e., the bottom of the trapezoid is open to the recessed area 2422). Other shapes of the recessed areas 2422 are possible, and the shape of the recessed areas 2422 is not strictly limited in this application.

Referring to fig. 14, fig. 14 is a top view of another embodiment of the electroacoustic transducer 200 shown in fig. 2, when the diaphragm 3 is hidden. The electroacoustic transducer 200 in the present embodiment is different from the foregoing embodiments in that: corner 242 includes an extrados 2423, and extrados 2423 is connected between two adjacent planes. The outer curved surface 2423 is convex in a direction approaching the voice coil 4. The outer cambered surface 2423 can be formed by rounding off between two adjacent side surfaces 241. The radius of the outer cambered surface 2423 is larger than or equal to the radius of the arc part 42 of the voice coil 4. The outer cambered surface 2423 and the voice coil 4 form the corner channel 2402, and the width W2 of the corner channel 2402 is larger than the width W1 of the side channel 2401. In the present embodiment, in the circumferential direction of the voice coil 4, the surface of the corner 242 facing the voice coil 4 is the outer cambered surface 2423, so that the width W2 of the corner channel 2402 changes smoothly, which helps the diaphragm 3 vibrate smoothly.

It is understood that, in other embodiments, the outer side 241 of the corner 242 facing the voice coil 4 may have other shapes, such as a wave shape, an inverted trapezoid shape, etc., which is not limited in this application.

Referring to fig. 15 and 16 together, fig. 15 is a top view of another embodiment of the electroacoustic transducer 200 shown in fig. 2 when the diaphragm 3 is hidden. Fig. 16 is a schematic diagram of the electroacoustic transducer 200 of fig. 2, in one embodiment, along the line C-C. The position of line C-C in fig. 2 in the structure shown in fig. 15 is illustrated in fig. 15. The structure shown in fig. 16 corresponds to the same embodiment of the electroacoustic transducer 200 as that shown in fig. 15.

The electroacoustic transducer 200 of the present embodiment is different from the foregoing embodiments in that: the corner channels 2402 are provided between the voice coil 4 and the corner 242 and in the corner 242. In other words, the corner channel 2402 includes a first portion 2405 and a second portion 2406. The first portion 2405 is provided between the voice coil 4 and the corner 242. The second portion 2406 is disposed in the corner 242. The first portion 2405 and the second portion 2406 communicate the medial posterior chamber 230 with the posterior chamber channel 210. The portion of the corner channel between the voice coil 4 and the corner 242 (i.e., the first portion 2405) has a first width W21. The first width W21 is a dimension of the first portion 2405 in a radial direction of the voice coil 4. Portions of the corner channels in the corners 242 (i.e., the second portions 2406) have a second width W22. The second width W22 is a dimension of the first portion 2405 in a radial direction of the voice coil 4. The sum of the first width W21 and the second width W22 is greater than the width W1 of the sideway 2401. The flow space formed by the corner channels (i.e., the first portion 2405) and the side channels 2401 between the voice coil 4 and the corner 242 is commonly referred to as an internal magnetic gap, and the flow space formed by the corner channels (i.e., the second portion 2406) in the corner 242 in parallel with the internal magnetic gap.

In this embodiment, the width of the two portions of the corner channel 2402 and the width W1 larger than the width W of the side channel 2401 increase the entire flow area of the channel 240, that is, equivalently increase the flow area of the inner magnetic gap, when the diaphragm 3 is driven by the voice coil 4 to vibrate, the airflow can more rapidly flow between the inner back cavity 230 and the back cavity channel 210, so as to reduce the damping of the electroacoustic transducer 200, improve the Q value (also referred to as quality factor) of the electroacoustic transducer 200, make the electroacoustic transducer 200 have higher sensitivity and higher loudness in a frequency band near Fo (resonant frequency), and also reduce distortion in a frequency band near Fo (resonant frequency), thereby obtaining better sound quality effect.

With continued reference to fig. 15 and 16, the corner 242 has a through hole 2427 and side cambered surfaces 2428. The side cambered surfaces 2428 are connected between the two side surfaces 241. The side cambered surfaces 2428 and the voice coil 4 form a part of the angular channel 2402, namely the first part 2405. The side cambered surfaces 2428 are provided such that the width of the first portion 2405 is gradually varied, thereby facilitating smooth vibration of the diaphragm 3. The through hole 2427 penetrates the upper central pole piece 24. The through hole 2427 forms another portion of the angular channel 2402, i.e., the second portion 2406. The through hole 2427 may be an elliptical hole, a circular hole, a polygonal hole, etc. For example, the through holes 2427 are elliptical holes, so that a smaller fluid flow resistance is obtained with the same flow area.

Wherein a portion of the corner channel 2402 between the side cambered surfaces 2428 and the voice coil 4 has the first width W21, and the first width W21 is greater than or equal to the width W1 of the side channel 2401. When the first width W21 is equal to the side channel 2401, the inner magnetic gap formed by the first portion 2405 and the side channel 2401 is not changed in the circumferential direction of the voice coil 4, so that the diaphragm 3 vibrates smoothly. When the first width W21 is greater than the width W1 of the side channel 2401, the flow area of the corner channel 2402 is larger, which is beneficial to increase the Q value of the electroacoustic transducer 200 and reduce the damping.

It will be appreciated that since the second portion 2406 of the corner channel 2402 is spaced apart from the first portion 2405, the shape of the first portion 2405 and the second portion 2406 can be designed relatively independently, and one skilled in the art can design the shape of the first portion 2405 and the second portion 2406 more flexibly.

Referring to fig. 16 and 17, fig. 17 is a schematic diagram illustrating a position relationship between the upper central pole piece 24 and the central magnet 22 shown in fig. 16. The central magnet 22 is provided with four escape areas 221. The four escape areas 221 communicate with the through holes 2427 (i.e., the second portion 2406) and the rear cavity channel 210 in a one-to-one correspondence. The projection of the avoiding region 221 on the lower pole piece 21 is partially overlapped with the projection of the angular channel 2402 on the lower pole piece 21. The shape of the projection of the central magnet 22 on the lower pole piece 21 is different from the shape of the projection of the upper central pole piece 24 on the lower pole piece 21. Since the central magnet 22 is made by sintering, the avoiding region 221 of the central magnet 22 is difficult to process into a complex shape, and the surface of the central magnet 22 contacting the avoiding region 221 may be a plane or a cambered surface. Of course, the surface of the central magnet 22 contacting the avoiding region 221 may have a different shape, or the central magnet 22 has the same contour shape (referring to the projection shape on the lower pole piece 21) as the upper central pole piece 24, if the manufacturing process allows.

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

Claims

1. An electroacoustic transducer is characterized by comprising a lower pole piece, a central magnet, a side magnet group, an upper central pole piece, an upper pole piece, a vibrating diaphragm and a voice coil;

the central magnet is arranged on the lower pole piece, the side magnet groups are arranged on the lower pole piece and surround the central magnet, a rear cavity channel is formed between the side magnet groups and the central magnet, the upper central pole piece is arranged on one side of the central magnet, which is far away from the lower pole piece, and the upper pole piece is arranged on one side of the side magnet groups, which is far away from the lower pole piece;

the voice coil is positioned between the upper side pole piece and the upper center pole piece, the voice coil is fixedly connected with the vibrating diaphragm, the vibrating diaphragm is positioned on one side of the upper center pole piece, which is far away from the center magnet, and an inner side rear cavity is formed among the vibrating diaphragm, the voice coil and the upper center pole piece;

the upper central pole piece comprises a plurality of side faces and corner parts connected between the adjacent side faces, a channel is arranged between the inner side rear cavity and the rear cavity channel and comprises a side channel and a corner channel, and the side channel is arranged between the voice coil and the side faces;

the corner channel is arranged between the voice coil and the corner part and in the corner part, the corner channel between the voice coil and the corner part is partially provided with a first width, the corner channel in the corner part is partially provided with a second width, and the sum of the first width and the second width is larger than the width of the side channel.

2. The electro-acoustic transducer of claim 1, wherein the inner back volume forms a first projection on the lower pole piece, wherein the channel forms a second projection on the lower pole piece, and wherein a ratio of an area of the second projection to an area of the first projection is 4.5% or greater.

3. The electro-acoustic transducer of claim 1, wherein when the corner channel is disposed between the voice coil and the corner portion, the corner portion includes an outer flat surface that connects between two adjacent side surfaces.

4. The electro-acoustic transducer of claim 3, wherein the corner comprises a recessed region that is recessed from the outer plane to an interior of the corner.

5. The electro-acoustic transducer of claim 1, wherein the voice coil includes a curved portion facing the corner portion, wherein when the angular channel is disposed between the voice coil and the corner portion, the corner portion includes an extrados surface, wherein the extrados surface is connected between two adjacent planes, and wherein a radius of the extrados surface is equal to or greater than a radius of the curved portion.

6. The electro-acoustic transducer of any one of claims 3 to 5, wherein the upper central pole piece forms a third projection on the lower pole piece and the central magnet forms a fourth projection on the lower pole piece, the third projection overlapping the fourth projection.

7. The electro-acoustic transducer of claim 6, wherein the third projection has an area larger than an area of the fourth projection, and wherein the third projection has a contour shape that is the same as a contour shape of the fourth projection.

8. The electro-acoustic transducer of claim 1, wherein when the angular channel is disposed between a voice coil and the corner portion and in the corner portion, the corner portion is provided with a through hole and a side arc surface, the side arc surface is connected between the two side surfaces, the side arc surface and the voice coil form a portion of the angular channel, and the through hole forms another portion of the angular channel.

9. The electro-acoustic transducer of claim 8, wherein a portion of the corner channel between the side arc and the voice coil has the first width, the first width being equal to or greater than a width of the side channel.

10. The electroacoustic transducer of claim 8 or 9 wherein the central magnet is provided with four escape areas, the four escape areas communicating the through holes with the back cavity channel in a one-to-one correspondence.

11. The electroacoustic transducer of any of claims 1 to 5 and 7 to 9, wherein an external magnetic gap is formed between the voice coil and the upper pole piece, the external magnetic gap comprises a first corner external magnetic gap and a second corner external magnetic gap, the corner channel comprises a first corner channel and a second corner channel, the first corner external magnetic gap and the first corner channel are respectively disposed on two sides of a same portion of the voice coil, the second corner external magnetic gap and the second corner channel are respectively disposed on two sides of a same portion of the voice coil, a width of the first corner external magnetic gap is greater than a width of the second corner external magnetic gap, and a width of the first corner channel is smaller than a width of the second corner channel.

12. The electro-acoustic transducer of claim 11, further comprising a lead wire, the lead wire comprising a connection end and a lead-out end, the connection end being connected to the voice coil, the lead-out end being for connection to an external circuit, the connection end being received in the first corner external magnetic gap.

13. A communication device comprising an electroacoustic transducer as claimed in any of the claims 1 to 12.