Transducers, loudspeakers and acoustic reproduction devices

Abstract

A converter, comprehensive: a magnetic circuit system, wherein the magnetic circuit system comprises a magnet arrangement and a magnetically conductive cover, wherein the magnetically conductive cover at least partially surrounds the magnet arrangement; a vibration plate, wherein the vibration plate comprises a first vibration plate and a second vibration plate, wherein the first vibration plate and the second vibration plate are each arranged on two sides of the magnet arrangement along a vibration direction of the transducer, and each elastically support the magnet arrangement; where the transducer's peak resonance frequency is less than 300 Hz.

Description

CROSS-REFERENCE TO RELATED REGISTRATIONS

[0001] This application claims priority over Chinese patent application No. CN202210877819.0, which was filed on July 25, 2022, and the entire contents of which are hereby incorporated by reference. TECHNICAL AREA

[0002] The present disclosure relates to the technical field of an electronic device, in particular to converters, loudspeakers and acoustic playback devices. BACKGROUND

[0003] Loudspeakers are widely used in everyday life. Existing loudspeakers often suffer from problems such as low sensitivity, high weight, magnetically distorted transducers, and weak magnetic field strength. This disclosure specifies transducers, loudspeakers, and acoustic playback devices that solve the aforementioned problems. SUMMARY

[0004] One embodiment of the present disclosure provides a transducer comprising: a magnetic circuit system, wherein the magnetic circuit system includes a magnet arrangement and a magnetically conductive cover, the magnetically conductive cover at least partially surrounding the magnet arrangement; a vibrating plate, wherein the vibrating plate comprises a first vibrating plate and a second vibrating plate, the first vibrating plate and the second vibrating plate each being arranged on two sides of the magnet arrangement along a vibration direction of the transducer, and the first vibrating plate and the second vibrating plate being configured to elastically support the magnet arrangement; and a coil arranged in the magnetic circuit system, wherein the coil is located within a magnetic field region of the magnet arrangement and the overall direct current (DC) impedance of the coil is in the range of 6 Ω to 10 Ω.

[0005] One embodiment of the present disclosure provides a transducer comprising: a magnetic circuit system, wherein the magnetic circuit system includes a magnet arrangement and a magnetically conductive cover, the magnetically conductive cover at least partially surrounding the magnet arrangement; a vibration plate, wherein the vibration plate comprises a first vibration plate and a second vibration plate, the first vibration plate and the second vibration plate each being arranged on two sides of the magnet arrangement along a vibration direction of the transducer, and the first vibration plate and the second vibration plate being configured to elastically support the magnet arrangement and to have a resonance peak frequency of the transducer of less than 300 Hz.

[0006] One embodiment of the present disclosure provides a transducer comprising: a magnetic circuit system, wherein the magnetic circuit system includes a magnet arrangement and a magnetically conductive cover, the magnetically conductive cover at least partially surrounding the magnet arrangement; a vibrating plate, wherein the vibrating plate comprises a first vibrating plate and a second vibrating plate, the first vibrating plate and the second vibrating plate each being arranged on two sides of the magnet arrangement along a vibration direction of the transducer, and the first vibrating plate and the second vibrating plate being configured to elastically support the magnet arrangement, wherein an equivalent stiffness of the first vibrating plate and / or the second vibrating plate in each direction within a plane perpendicular to the vibration direction of the magnet arrangement is greater than 4.7 × 10 4 N / m.

[0007] One embodiment of the present disclosure provides a transducer comprising: a magnetic circuit system, wherein the magnetic circuit system includes a magnet arrangement and a magnetically conductive cover, the magnetically conductive cover at least partially surrounding the magnet arrangement; a vibrating plate, wherein the vibrating plate comprises a first vibrating plate and a second vibrating plate, the first vibrating plate and the second vibrating plate each being arranged on two sides of the magnet arrangement along a vibration direction of the transducer, and the first vibrating plate and the second vibrating plate being configured to elastically support the magnet, the magnet being provided with a first hole, and each of the magnetically conductive plates being provided with a second hole corresponding to the first hole.

[0008] One embodiment of the present disclosure provides a transducer comprising: a magnetic circuit system, wherein the magnetic circuit system includes a magnet arrangement and a magnetically conductive cover, the magnetically conductive cover at least partially surrounding the magnet arrangement; a vibrating plate, wherein the vibrating plate comprises a first vibrating plate and a second vibrating plate, the first vibrating plate and the second vibrating plate each being arranged on two sides of the magnet arrangement along a vibration direction of the transducer, and the first vibrating plate and the second vibrating plate being configured to elastically support the magnet, wherein a ratio of the thickness of each magnetically conductive plate to the thickness of the magnet is in the range of 0.05 to 0.35.

[0009] One embodiment of the present disclosure provides a transducer comprising: a magnetic circuit system, wherein the magnetic circuit system includes a magnet arrangement and a magnetically conductive cover, the magnetically conductive cover at least partially surrounding the magnet arrangement; a vibrating plate, wherein the vibrating plate comprises a first vibrating plate and a second vibrating plate, the first vibrating plate and the second vibrating plate each being arranged on two sides of the magnet arrangement along a vibration direction of the transducer, and the first vibrating plate and the second vibrating plate being configured to elastically support the magnet, wherein at least one of the magnets, a magnetically conductive plate of the magnetically conductive plates, and the magnetically conductive cover comprising several magnetic parts with different magnetization directions.

[0010] One embodiment of the present disclosure provides a loudspeaker comprising a housing, an electronic component and a transducer according to any embodiment described in the present disclosure, wherein the housing forms a cavity that accommodates the transducer and the electronic component.

[0011] One embodiment of the present disclosure provides an acoustic playback device comprising a mounting arrangement and a loudspeaker according to any embodiment described in the present disclosure, wherein the mounting arrangement is connected to the loudspeaker. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1(a) is a schematic representation of a user carrying a loudspeaker according to some embodiments of the present disclosure; Fig. 1(b) is a schematic representation of a user carrying a loudspeaker according to some embodiments of the present disclosure; Fig. 1(c) is a schematic representation of a user carrying a loudspeaker according to some embodiments of the present disclosure; Fig. 2(a) is a structural diagram showing a loudspeaker according to some embodiments of the present disclosure; Fig. 2(b) is a structural diagram showing a magnetically conductive cover according to some embodiments of the present disclosure; Fig. 2(c) is an exemplary schematic diagram showing a position of a first magnetically conductive plate and a position of a first coil according to some embodiments of the present disclosure; Fig. Figure 3 is a structural diagram showing a loudspeaker according to some embodiments of the present disclosure; Fig. Figure 4 is a structural diagram showing a loudspeaker according to some embodiments of the present disclosure; Fig. 5(a) is a structural diagram showing a loudspeaker according to some embodiments of the present disclosure; Fig. 5(b) is a comparison diagram showing the effect of different distances between a bone conduction loudspeaker and an air conduction loudspeaker on the magnetic field of a coil according to some embodiments of the present disclosure; Fig. Figure 6 is a schematic diagram showing the structure of a converter according to some embodiments of the present disclosure; Fig. 7(a) is an exploded view of a converter according to some embodiments of the present disclosure; Fig. 7(b) is a comparison diagram showing the impedances between single-coil and double-coil converters according to some embodiments of the present disclosure; Fig. 7(c) is a partially schematic representation of a cylindrical, magnetically conductive cover according to some embodiments of the present disclosure; Fig. 7(d) is a schematic representation of a shell-shaped, magnetically conductive cover according to some embodiments of the present disclosure; Fig. Figure 8 is a comparison diagram showing frequency response curves for slotted and unslotted magnetically conductive covers; Fig. 9(a) is a top view showing a magnetically conductive plate according to some embodiments of the present disclosure; Fig. 9(b) is a top view showing a magnetically conductive plate according to some embodiments of the present disclosure; Fig. 9(c) is a top view showing a magnetically conductive plate according to some embodiments of the present disclosure; Fig. Figure 10 is a comparison diagram showing frequency response curves when a magnetically conductive plate is perforated and unperforated according to some embodiments of the present disclosure; Fig. Figure 11 is a comparison diagram showing frequency response curves when a magnetically conductive plate is perforated and unperforated according to some embodiments of the present disclosure; Fig. Figure 12 is a comparison diagram showing BL value curves when a second hole is located on a magnetically conductive plate at different distances from the center of the magnetically conductive plate according to some embodiments of the present disclosure; Fig. Figure 13 is a comparison diagram showing frequency response curves when a second hole has different diameters according to some embodiments of the present disclosure; Fig. 14(a) is a comparison diagram showing the BL value curves when a second hole has different diameters according to some embodiments of the present disclosure; Fig. 14(b) is a comparison diagram showing the acceleration curves of loudspeakers within a mass range of 2g - 5g according to some embodiments of the present disclosure; Fig. 15(a) is a schematic diagram showing the structure of a diaphragm according to some embodiments of the present disclosure; Fig. 15(b) is a schematic diagram showing the structure of a diaphragm according to some embodiments of the present disclosure; Fig. 15(c) is a schematic diagram showing the structure of a diaphragm according to some embodiments of the present disclosure; Fig. 16(a) is a schematic diagram showing the structure of a diaphragm according to some embodiments of the present disclosure; Fig. 16(b) is a schematic diagram showing the structure of a membrane according to some embodiments of the present disclosure; Fig. 17(a) is a schematic diagram showing the structure of a magnetic circuit system in the form of a Halbach array according to some embodiments of the present disclosure; Fig. 17(b) is a schematic diagram showing the structure of a magnetic circuit system in the form of a Halbach array according to some embodiments of the present disclosure; Fig. 17(c) is a schematic diagram showing the structure of a magnetic circuit system in the form of a Halbach array according to some embodiments of the present disclosure; Fig. 17(d) is a schematic diagram showing the structure of a magnetic circuit system in the form of a Halbach array according to some embodiments of the present disclosure; Fig. 17(e) is a schematic diagram showing the structure of a magnetic circuit system in the form of a Halbach array according to some embodiments of the present disclosure; Fig. 17(f) is a schematic diagram showing the structure of a magnetic circuit system in the form of a Halbach array according to some embodiments of the present disclosure; Fig. 17(g) is a schematic diagram showing the structure of a magnetic circuit system in the form of a Halbach array according to some embodiments of the present disclosure; and Fig. Figure 18 is a comparison diagram showing BL value curves of magnetic circuit systems with different magnetic arrangements according to some embodiments of the present disclosure. DETAILED DESCRIPTION

[0012] The technical diagrams of the embodiments of the present disclosure will be described more clearly below, and the accompanying drawings, which must be configured in the description of the embodiments, will be briefly described below. Obviously, the drawings in the following description are only some examples or embodiments of the present disclosure, and will be applied to other similar scenarios based on these accompanying drawings without payment for creative work. Unless it is obvious from the context or the context clarifies otherwise, the same number in the drawings refers to the same structure or operation.

[0013] It is understood that the terms "system," "device," "unit," and / or "module" used here are a method for distinguishing between different components, elements, parts, or assemblies at different levels. However, if other terms serve the same purpose, these terms can be replaced by other expressions.

[0014] As shown in the present disclosure and the claims, “a”, “an”, and / or “the” are not specifically singular, and the plural may be included unless the context clearly requires an exception. It is further understood that the terms “comprise”, “comprises”, and / or “containing”, “include”, “includes”, and / or “enclosing”, when used in the present disclosure, specify the presence of certain features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0015] The embodiments of the present disclosure describe an acoustic playback device 100. In some embodiments, the acoustic playback device 100 may comprise a loudspeaker 10 and a mounting arrangement 20, wherein the loudspeaker 10 is connected to the mounting arrangement 20. The mounting arrangement 20 may be configured such that the loudspeaker 10 is worn in a carrying position. In some embodiments, the carrying position may be a specific position on the user's head. The carrying position may include, for example, the ear, the mastoid process, the temporal bone, the parietal bone, the frontal bone, etc. As another example, the carrying position may include positions on the left and right sides of the head and on the front of the user's ears along the sagittal axis of the human body.In some embodiments, the loudspeaker 10 may include a transducer that can be configured to convert electrical signals (containing sound information) into mechanical vibrations so that the user can hear sound via the acoustic playback device 100. Specifically, the mechanical vibrations generated by the loudspeaker 10 may be transmitted primarily through media such as the user's skull (i.e., bone conduction) to form bone-conducted sound, or primarily through media such as air (i.e., air conduction) to form air-conducted sound, or they may use a combination of bone conduction and air conduction for sound transmission. Further information about the loudspeaker 10 can be found in the [reference to be added]. Fig. 2(a)-4 and the associated descriptions.

[0016] In some embodiments, the fastening arrangement 20 can be ring-shaped and encircle the user's head over the forehead and back of the head. In some embodiments, the fastening assembly 20 can be a curved structure attached to the back of the user's head. In some embodiments, the fastening arrangement 20 can be an ear-hook structure with a curved portion that hangs over the user's ear. In some embodiments, the fastening arrangement 20 can be a spectacle frame structure with nose pads and temples that can be worn on the user's face and ears. Further embodiments of the fastening arrangement 20 are described in the Fig. 1 (a)-1(c) and the associated descriptions can be found.

[0017] Fig. Figures 1(a)-1(c) are schematic representations showing the wearing of an acoustic playback device 100 by a user according to some embodiments of the present disclosure. In some embodiments, as in Fig. As shown in Figure 1(a), the mounting arrangement 20 can be arranged in a ring shape and enclose the user's ears, so that the loudspeaker 10 is attached to the user's face and close to the user's ear canal. In some embodiments, as shown in Figure 1(a), the mounting arrangement 20 can be arranged in a ring shape and enclose the user's ears, so that the loudspeaker 10 is attached to the user's face and close to the user's ear canal. Fig. As shown in Figure 1(b), the fastening arrangement 20 can comprise an ear hook and a rearward-mounted structure. The ear hook and the rearward-mounted structure work together to enclose the back of the user's head and auricle, thereby securing the loudspeaker 10 to the user's face and close to the user's ear canal. In some embodiments, as shown in Figure 1(b), the fastening arrangement 20 can also include an ear hook and a rearward-mounted structure. The ear hook and the rearward-mounted structure work together to enclose the back of the user's head and ear, thus securing the loudspeaker 10 to the user's face and close to the user's ear canal. Fig. As shown in 1(c), the fastening arrangement 20 can be a curved head beam structure that wraps around the upper part of the user's head, thereby fastening the loudspeaker 10 to the user's face and close to the user's ear canal.

[0018] In some embodiments, the acoustic playback device 100 can comprise at least two loudspeakers 10. All of the at least two loudspeakers 10 can convert electrical signals into mechanical vibrations, enabling the acoustic playback device 100 to produce stereo effects. For example, the acoustic playback device 100 can contain two loudspeakers 10. The two loudspeakers 10 can be positioned on the left and right sides of the user's ear, respectively. In some application scenarios where stereo sound is not particularly important (e.g., hearing aids for hearing-impaired patients, teleprompters for live broadcasts, etc.), the acoustic playback device 100 can also contain only one loudspeaker 10.

[0019] If the acoustic playback device 100 comprises two loudspeakers 10, the fastening device 20 may, for example, comprise two ear hooks and a rear-mounted device. Two ends of the rear-mounted device are each connected to one end of a corresponding ear hook assembly. The other end of each ear hook assembly, opposite the rear-mounted device, is connected to a corresponding loudspeaker 10. In particular, the rear-mounted device may be curved to wrap around the back of the user's head, and the ear hook components may also be curved to hang between the user's ears and head, thus simplifying the wearing requirements of the acoustic playback device 100. When the acoustic playback device 100 is worn, the two loudspeakers 10 are located on the left and right sides of the user's head, respectively.The two loudspeakers 10, in conjunction with the mounting arrangement 20, press against the user's head so that the user can hear the sound emitted by the acoustic playback device 100.

[0020] In some embodiments, the loudspeaker 10 described in the present disclosure can be a bone conduction loudspeaker and / or an air conduction loudspeaker. In some embodiments, the acoustic playback device 100 can be an electronic device with audio functionality. For example, the acoustic playback device 100 can be an electronic device such as music headphones, hearing aid headphones, bone conduction headphones, a hearing aid, audio glasses, a smart helmet, a VR device, an AR device, etc.

[0021] Fig. 2(a) is a structural diagram showing a loudspeaker according to some embodiments of the present disclosure. As in Fig. As shown in Figure 2(a), the loudspeaker 10 can comprise a housing 11, a transducer 12, and a vibrating disc 13. The housing 11 can form a receiving cavity for the transducer 12. The transducer 12 can be arranged in the receiving cavity of the housing 11, and the vibrating disc 13 can be connected to the transducer 12 and configured to transmit the mechanical vibrations generated by the transducer 12 to the user. The mounting component 20 can be connected to an outer surface of the housing 11. In some embodiments, the transducer 12 can convert electrical signals into mechanical vibrations. The vibrating disc 13 can come into contact with the user's skin when worn. The mechanical vibrations generated by the transducer 12 are transmitted to the vibrating disc and act on the user's auditory nerve via the skin, bone, and / or tissue, thus producing bone-conducted sound.It should be noted that the housing 11 can be rectangular, circular, diamond-shaped, polygonal or any irregular shape and combinations thereof, and is not limited to the shape shown in the illustration.

[0022] In some embodiments, the loudspeaker 10 may also include a damping plate 14. The transducer 12 may be suspended via the damping plate 14 in the receiving cavity of the housing 11. The vibration disc 13 must not touch the housing 11. In this case, due to the presence of the damping plate 14, the mechanical vibrations generated by the transducer 12 are transmitted to the housing 11 to a lesser extent or not at all, thereby preventing, to some degree, the vibrations of the air outside the loudspeaker 10 caused by the housing 11. This helps to reduce sound losses from the loudspeaker 10. In some embodiments, the housing 11 may have an open end, and the vibration disc 13 is arranged outside the housing 11 and faces the open end. In other words, one edge of the vibration disc 13 is decoupled from the open end of the housing 11.A connecting rod 131 is provided between the vibrating disc 13 and the transducer 12. One end of the connecting rod 131 is connected to the transducer 12, and the other end extends through the open end of the housing 11 to connect to the vibrating disc 13, thus preventing the vibrating disc 13 and the transducer 12 from contacting the housing 11 and thereby reducing sound leakage from the loudspeaker 10. In some embodiments, the damping plate 14 can be connected between the connecting rod 131 and the housing 11 to suspend the vibrating disc 13 and the transducer 12. In some embodiments, at least one through-hole (also known as a "sound leakage reduction hole") can be provided in the housing 11 to connect the receiving cavity of the housing 11 to the outside of the loudspeaker 10, thereby reducing sound leakage from the loudspeaker 10.

[0023] In some embodiments, the speaker 10 may also include a face cushion (not shown in the figure) connected to the vibration disc 13. The face cushion is configured to touch the user's skin, meaning that the vibration disc 13 can make contact with the user's skin via the face cushion. The Shore hardness of the face cushion may be lower than that of the vibration disc 13, meaning that the face cushion may be softer. For example, the material of the face cushion may be a soft material such as silicone, while the material of the vibration disc 13 may be a hard material such as polycarbonate or glass-fiber reinforced plastic. This can improve the wearing comfort of the speaker 10, allow the speaker 10 to conform closely to the user's skin, and further enhance the sound quality of the speaker 10.In some embodiments, the face cushion can be detachably connected to the vibration disc 13 to allow for easy replacement by the user. For example, the face cushion can be slipped over the vibration disc 13.

[0024] As in Fig. As shown in Figure 2(a), the transducer 12 can comprise a support 121, a vibration plate 122, a magnetic circuit system 123, and a coil 124. In some embodiments, the vibration plate 13 can be connected to the support 121. ... Fig. As shown in Figure 2(a), the support 121 can, for example, be connected to an end of the connecting rod 131 located away from the vibrating disc 13. The support 121 can be connected to the magnetic circuit system 123 via the vibrating plate 122, thereby suspending the magnetic circuit system 123 in the receiving cavity of the housing 11. In some embodiments, the damping plate 14 can connect the support 121 and the housing 11, thereby suspending the transducer 12 in the receiving cavity of the housing 11. The coil 124 can extend into a magnetic gap of the magnetic circuit system 123 in a vibration direction of the transducer 12.

[0025] In some embodiments, the magnetic circuit system 123 can comprise a magnetic assembly 1231 and a magnetically conductive cover 1232. The magnetically conductive cover 1232 can be positioned over the coil 124, and the magnetic assembly 1231 can be positioned inside the coil 124. The magnetically conductive cover 1232 and the magnetic assembly 1231 are spaced apart from each other in a direction perpendicular to the direction of vibration, creating the aforementioned magnetic gap between an inner wall of the magnetically conductive cover 1232 and an outer surface of the magnetic assembly 1231. In some embodiments, the coil 124 can be wound around the outer surface of the magnetic assembly 1231 along an axis parallel to the direction of vibration of the transducer 12.In some embodiments, the magnetically conductive cover 1232 of the magnetic circuit system 123 encloses an axis parallel to the vibration direction of the transducer 12 outside the coil 124, meaning that the magnetically conductive cover 1232 and the magnet arrangement 1231 are spaced apart from each other in a direction perpendicular to the vibration direction of the transducer 12. In particular, the coil 124 may be connected to the magnetically conductive cover 1232. In some embodiments of the present disclosure, the coil 124 is attached to the inner wall of the magnetically conductive cover 1232. In some embodiments, the vibration plate 122 may be arranged such that it connects the magnetically conductive cover 1232 and the magnet arrangement 1231. The vibration plate 122 may serve as an elastic support for the magnet arrangement 1231.For example, the vibrating plate 122 and the magnetic circuit system 123 can be arranged in the direction of vibration, and one side of the vibrating plate 122 perpendicular to the direction of vibration can be connected to one end of the magnetically conductive cover 1232 perpendicular to the direction of vibration, thereby fixing the magnetic circuit system 123. It is understood that in other embodiments of the present disclosure, a circumference of the vibrating plate 122 can also be connected to the inner wall of the magnetically conductive cover 1232 or to other positions, thereby fixing the magnetic circuit system 123 relative to the magnetically conductive cover 1232.

[0026] In some embodiments, the coil 124 can comprise a first coil 1241 and a second coil 1242. In some embodiments, the first coil 1241 can extend into the magnetic gap of the magnetic circuit system 123 from a side closer to the vibrating disk 13 in the direction of vibration, and the second coil 1242 can extend into the magnetic gap of the magnetic circuit system 123 from a side farther from the vibrating disk 13 in the direction of vibration. In some embodiments, the first coil 1241 and the second coil 1242 can be inserted together into the magnetic gap of the magnetic circuit system 123 from the side closer to the vibrating disk 13 to simplify the assembly process. In some embodiments, the transducer 12 can also have a retaining section to maintain the shape of the first coil 1241 and the second coil 1242.For example, the first coil 1241 and the second coil 1242 can be integrated into a single structure. Specifically, the first coil 1241 and the second coil 1242 can be wound around a shaping material, and then the holding section (e.g., high-temperature tape or other holding material) can be bonded to the outside of the first coil 1241 and the second coil 1242, creating an integrated structure. The first coil 1241 and the second coil 1242, attached to the holding section, extend into the magnetic gap of the magnetic circuit system 123 from the same side of the vibrating disk 13, thus simplifying the assembly process of the coil 124.In some embodiments, the two coils are wound from the same metal wire, or a segment of the two coils is connected, so that there are only two lead wires for the input and output of the two coils, which simplifies the wiring and subsequent electrical connections with other structures.

[0027] In some embodiments, the vibrating plate 122 can comprise a first vibrating plate 125 and a second vibrating plate 126. Along the vibration direction of the transducer 12, the first vibrating plate 125 and the second vibrating plate 126 can elastically support the magnet arrangement 1231 from opposite sides. Therefore, in the embodiments described in the present disclosure, the magnet arrangement 1231 is elastically supported on opposite sides in the vibration direction of the transducer 12, thus being free from significant shocks or other abnormal vibrations, which improves the stability of the vibrations of the transducer 12.

[0028] As in Fig. As shown in Figure 2(a), for example, the edge regions 1253 of the first vibrating plate 125 are connected in the vibration direction to a side of the support 121 near the magnetic circuit system 123 or to a side of the magnetically conductive cover 1232 near the support 121. An edge region 1263 of the second vibrating plate 126 is connected to a side of the magnetically conductive cover 1232 farther from the support 121. In some embodiments, the magnetically conductive cover 1232 can be a tubular structure with both ends open (e.g., as in Figure 2(a)). Fig. 2(a)-2(b) shown), a shell-shaped structure in which one end is open (e.g. as in Fig. 7(d) shown), etc. In some embodiments, punched holes can be provided in the magnetically conductive cover 1232 (e.g., punched holes in the side walls of a tubular magnetically conductive cover (e.g., as shown in Fig. 7(c)) or punched holes in the base and sides of a shell-shaped magnetically conductive cover (e.g. as in Fig. 7(d)) ​​etc.) reduce the acoustic chamber effect of the magnetic circuit system 123, thereby reducing the sound leakage of the acoustic playback device 100. In some embodiments, the magnetically conductive cover 1232 can be a closed structure that prevents the sound generated in the magnetic circuit system 123 from escaping. Fig. 2(b) is a structural diagram showing the magnetically conductive cover 1232 according to some embodiments of the present disclosure. As in Fig. As shown in Figure 2(b), the ends of the tubular structure with both open ends can be closed by cover plates 1232-1 and 1232-2 along the vibration direction of the transducer 12 to form a closed magnetically conductive cover 1232. It should be understood that the cover plates are only one example and other methods (e.g., a cover film) can also be configured to close the ends of the tubular structure with both open ends along the vibration direction to form a closed magnetically conductive cover 1232. In other embodiments where the requirement for the concentration of the magnetic field generated by the magnet arrangement 1231 is not very high, the magnetically conductive cover 1232 can also be replaced by a non-magnetic part, such as a plastic bracket.Based on this, the edge areas of the first vibration plate 125 and the second vibration plate 126 can each be connected to both ends of the plastic holder.

[0029] In some embodiments, the magnet arrangement 1231 can comprise a magnet 1233 and a magnetically conductive plate. In some embodiments, the magnet 1233 and the magnetically conductive plate are arranged along the vibration direction of the transducer 12. In some embodiments, the magnetically conductive plate can be arranged on one or both sides of the magnet 1233 in the vibration direction of the transducer 12. In some embodiments, the magnetically conductive plate can comprise a first magnetically conductive plate 1234 and a second magnetically conductive plate 1235, which are located on opposite sides of the magnet 1233 in the vibration direction of the transducer 12.The first vibrating plate 125 can support the magnet arrangement 1231 from one side of the first magnetically conductive plate 1234 facing away from the second magnetically conductive plate 1235, and the second vibrating plate 126 can support the magnet arrangement 1231 from one side of the second magnetically conductive plate 1235 facing away from the first magnetically conductive plate 1234. For example, a central area 1252 of the first vibrating plate 125 is connected to the side of the first magnetically conductive plate 1234 facing away from the second magnetically conductive plate 1235, and a central area 1262 of the second vibrating plate 126 is connected to the side of the second magnetically conductive plate 1235 facing away from the first magnetically conductive plate 1234. In some embodiments, the corners of the magnetically conductive plates facing away from the magnet 1233 (e.g.the first magnetically conductive plate 1234 and / or the second magnetically conductive plate 1235) may be chamfered. For example, the corners on opposite sides of the first magnetically conductive plate 1234 and the second magnetically conductive plate 1235 (i.e., the corners furthest from the magnet 1233) may be chamfered to adjust the distribution of the magnetic field generated by the magnetic circuit system 123 and to concentrate the magnetic field.In some embodiments, in the vibration direction of the transducer 12, half the height of the first coil 1241 can be equal to half the thickness of an edge line parallel to the vibration direction of the first magnetically conductive plate 1234, and half the height of the second coil 1242 can be equal to half the thickness of the edge line parallel to the vibration direction of the second magnetically conductive plate 1235, thereby concentrating the magnetic field in the rectangular sections of the first magnetically conductive plate 1234 and / or the second magnetically conductive plate 1235 that are not the beveled sections. Fig. Figure 2(c) is an exemplary schematic representation showing a position of the first magnetically conductive plate 1234 and a position of the first coil 1241 according to some embodiments of the present disclosure. As in Fig. As shown in Figure 2(c), along the vibration direction of the transducer 12, half the height H1 of the first coil 1241 is equal to half the thickness H2 of an edge line 1234-1 of the first magnetically conductive plate 1234 parallel to the vibration direction. Both half the height H1 and half the thickness H2 lie on a contour line L. In some embodiments, to simplify the manufacture of the magnetically conductive plates (e.g., the first magnetically conductive plate 1234 and / or the second magnetically conductive plate 1235), the corners of the magnetically conductive plates (e.g., the first magnetically conductive plate 1234 and / or the second magnetically conductive plate 1235) furthest from the magnet 1233 can be at right angles. For example, the corners on opposite sides of the first magnetically conductive plate 1234 and the second magnetically conductive plate 1235 (i.e., the corners furthest from the magnet 1233) may not be chamfered.In this case, along the vibration direction of the transducer 12, half the height of the first coil 1241 is equal to half the thickness of the first magnetically conductive plate 1234, and half the height of the second coil 1242 is equal to half the thickness of the second magnetically conductive plate 1235, thus concentrating the magnetic field on the first magnetically conductive plate 1234 and / or the second magnetically conductive plate 1235. Compared to the beveled first magnetically conductive plate 1234 and the second magnetically conductive plate 1235, the non-beveled first magnetically conductive plate 1234 and the non-beveled second magnetically conductive plate 1235 can have a small thickness, thereby achieving the goal of reducing the weight and volume of the entire transducer 12.

[0030] In some embodiments, the magnetically conductive cover 1232 can be connected to the bracket 121, and the bracket 121 can be connected to the housing 11 via the damping plate 14, thereby suspending the transducer 12 in the receiving chamber of the housing 11. At this point, as shown in Fig. 2(a) shown, the edge regions 1253 of the first vibrating plate 125 along both ends perpendicular to the direction of vibration can be connected to the support 121 and the magnetically conductive cover 1232, the edge region 1263 of the second vibrating plate 126 along both ends perpendicular to the direction of vibration can be connected to the magnetically conductive cover 1232, and the vibrating disk 13 can be connected to the support 121 and separated from the open end of the housing 11.

[0031] In some embodiments, it is difficult for the magnetic circuit system 123 to be stably suspended within the housing 11 by the damping plate 14 if the stiffness of the damping plate 14 is too low, which easily leads to poor stability during vibration of the transducer 12. Conversely, if the stiffness of the damping plate 14 is too high, the vibration of the transducer 12 tends to be transmitted to the housing 11 via the damping plate 14, resulting in excessive sound leakage from the loudspeaker 10. In some embodiments, the ratio between the stiffness of the damping plate 14 and the stiffness of the first vibration plate 125 (or the second vibration plate 126) can be in a range of 0.1 to 5 in order to achieve good stability during vibration of the transducer 12 and to reduce sound leakage from the loudspeaker 10.

[0032] Fig. Figure 3 is a structural diagram showing the loudspeaker 10 according to some embodiments of the present disclosure. As in Fig. As shown in Figure 3, the loudspeaker 10 in this embodiment is essentially the same as the one shown in Figure 3. Fig. 2(a) the embodiment shown, the main difference being that in this embodiment the magnetically conductive cover 1232 is rigidly connected to the housing 11 or the vibration disc 13, which means that the damping plate 14 cannot be present in this embodiment. Furthermore, in this embodiment the magnetically conductive cover 1232 is attached to the inner wall of the housing 11, thereby fully utilizing the interior of the housing 11, which is conducive to the miniaturization of the loudspeaker 10. It is understood that in other embodiments of the present disclosure the magnetically conductive cover 1232 may also be rigidly connected to the housing 11 or the vibration disc 13 by other fastening structures. In some embodiments the edge regions (e.g.The edge region 1253 or the edge region 1263) of either the first vibratory plate 125 or the second vibratory plate 126 is connected to the open end of the housing 11 by one or a combination of assembly methods such as clipping or gluing, and the vibratory disc 13 is connected to the open end of the housing 11, thereby forming a closed cavity. In some embodiments, the side of either the first vibratory plate 125 or the second vibratory plate 126 that is located near the vibratory disc 13 is connected to the vibratory disc 13, and the vibratory disc 13 is connected to the open end of the housing 11. In some embodiments, the vibratory disc 13 can be made of the same material as the housing 11 and be formed in one piece.In some embodiments, the vibrating disc 13 may be made of a different material than the housing 11 and may be joined by one or a combination of mounting methods such as clipping or gluing.

[0033] In some embodiments, the loudspeaker 10 may also include an electronic component. The electronic component is located in the receiving cavity of the housing 11 or attached to the outside of the housing 11. In some embodiments, the electronic component may include a vibration-sensitive component and a non-vibration-sensitive component. The vibration-sensitive component may include an air-conduction loudspeaker, an accelerometer, etc. The non-vibration-sensitive component may include a battery, a printed circuit board, etc. The battery may be configured to power the loudspeaker 10, enabling its operation. The printed circuit board may be integrated with a signal processing circuit configured for processing electrical signals.In some embodiments, the signal processing may include frequency modulation processing, amplitude modulation processing, filter processing, noise reduction processing, etc. The air conduction loudspeaker may be configured to convert electrical signals into vibration signals (sound waves) that are transmitted through the air to the auditory nerve and perceived by the user. The accelerometer may be configured to measure the vibration acceleration of the vibrating disc 13. Further information about the air conduction loudspeaker and the accelerometer can be found below, e.g., in the descriptions of the [references to be added]. Fig. 4-9(c).

[0034] In the various embodiments described in Fig. 2(a) and Fig. As shown in Figure 3, the loudspeaker 10 can be a bone conduction loudspeaker. Various embodiments are described below in which the acoustic playback device 100 can be implemented as a bone-to-air conduction loudspeaker or as a bone-to-air conduction earphone by... Fig. 4-9(c).

[0035] Fig. Figure 4 is a structural diagram showing the loudspeaker 10 according to some embodiments of the present disclosure. The one in Fig. The 4 loudspeakers shown (10) are essentially the same as the one in Fig. 2(a) Loudspeaker 10 shown, with the main difference being that the electronic component of the loudspeaker 10 comprises an air-conducting loudspeaker arranged within the receiving cavity of the housing 11. As in Fig. As shown in Figure 4, the loudspeaker 10 comprises a transducer 12 and a housing 11 that accommodates the transducer 12. The transducer 12 comprises a magnetic circuit system 123 (including a magnetically conductive cover 1232 and a magnet assembly 1231), a coil 124 (including a first coil 1241 and a second coil 1242), and a vibration plate 122 (including a first vibration plate 125 and a second vibration plate 126). The coil 124 is arranged in the magnetic circuit system 123 such that the magnetic fields B1, B2 of the magnetic circuit system 123 pass through the coil 124. The first vibration plate 125 and the second vibration plate 126 elastically support the magnet assembly 1231. The air-conducting loudspeaker contains a diaphragm 15 which is connected between the magnet assembly 1231 and the housing 11, and the diaphragm 15 divides the interior of the housing 11 (i.e.the aforementioned receiving cavity) into a front cavity 111 near a skin contact area (e.g., the vibration disc 13) and a rear cavity 112 far from the aforementioned skin contact area. In other words, when the user wears the loudspeaker 10, the front cavity 111 is closer to the user than the rear cavity 112. In some embodiments, the housing 11 is provided with a sound outlet hole 113 connected to the rear cavity 112, and the diaphragm 15 can generate air-conduction sound that is transmitted to the human ear through the sound outlet hole 113 during the relative movement between the transducer 12 and the housing 11. In this way, the sound generated in the rear cavity 112 can be transmitted through the sound outlet hole 113 and then act via the air on the user's eardrum, allowing the user to hear the air-conduction sound through the loudspeaker 10.

[0036] In some embodiments, the diaphragm 15 of the air-conduction loudspeaker is connected between the magnet assembly 1231 and the housing 11 of the transducer 12, and one vibration direction of the diaphragm 15 is parallel to the vibration direction of the transducer 12. When the transducer 12 moves the skin contact area towards the user's face, this can simply be considered sound amplification by bone conduction (see Fig. 4) Simultaneously, a portion of the housing 11, corresponding to the skin contact area, moves towards the user's face, while the magnet assembly 1231 moves in the opposite direction due to the action-reaction relationship, compressing the air in the rear cavity 112. This corresponds to an increase in air pressure, resulting in amplified sound transmitted through the sound outlet 113, which can be considered simply as air conduction amplification. Therefore, the bone conduction sound and the air conduction sound from the loudspeaker 10 can be amplified simultaneously, and if the bone conduction sound decreases, the air conduction sound also decreases accordingly. Based on this, the bone conduction sound and the air conduction sound generated by the loudspeaker 10 have the property of being in phase.If the front cavity 111 is a closed cavity, the front cavity 111 and the rear cavity 112 are generally separated by structural components such as the diaphragm 15 and the transducer 12, so that the air pressure change pattern in the front cavity 111 is opposite to that in the rear cavity 112. In some embodiments, the housing 11 may also be provided with a pressure relief hole connected to the front cavity 111, or the front cavity 111 may be designed as an open opening, so that the front cavity 111 is connected to the external environment and air can freely enter and exit the front cavity 111. In this way, the change in air pressure in the rear cavity 112 by the front cavity 111 can be minimized, thereby effectively improving the acoustic performance of the air conduction sound generated by the loudspeaker 10.In some embodiments, the pressure relief hole in the front cavity 111 can be arranged offset from the sound outlet hole 113 in the rear cavity 112, i.e., they are not adjacent. For example, the pressure relief hole is located on one side of the housing 11 and the sound outlet hole 113 is located on the opposite side of the housing 11, opposite the pressure relief hole, in order to minimize the possibility of sound cancellation due to opposing phases.

[0037] To prevent the air conduction loudspeaker from resonating and generating leakage peaks due to the vibration of the transducer 12, in some embodiments the air conduction vibration direction of the air conduction loudspeaker may be different from the vibration direction of the transducer 12 (i.e. the bone conduction vibration direction) to prevent mutual interference in the same direction. Fig. Figure 5(a) is a structural diagram showing the loudspeaker 10 according to some embodiments of the present disclosure. As in Fig. As shown in Figure 5(a), an air-conduction loudspeaker 16 is inserted into the side wall of the housing 11. The air-conduction loudspeaker 16 is connected to the transducer 12, and the transducer 12 and the housing 11 together form a bone-conduction loudspeaker within the loudspeaker 10. The bone-conduction loudspeaker, together with the air-conduction loudspeaker 16, forms a bone-air-conduction loudspeaker. In some embodiments, the air-conduction vibration direction of the air-conduction loudspeaker 16 differs from the vibration direction of the transducer 12 (i.e., the bone-conduction vibration direction). In some embodiments, the vibration direction of the transducer 12 may be approximately perpendicular to the air-conduction vibration direction of the air-conduction loudspeaker 16. For example, the vibration direction of the transducer 12 may be approximately perpendicular to the vibration direction of the diaphragm of the air-conduction loudspeaker 16 in order to reduce sound losses of the air-conduction loudspeaker.The term "approximately right-angled" refers to an angle between the respective two parts within a range of 90° ± 20°. For example, the angle between the vibration direction of the transducer 12 and the air conduction vibration direction (or the diaphragm of the air conduction loudspeaker 16) lies within a range of 90° ± 20°. For instance, the vibration direction of the transducer 12 may be perpendicular to a diaphragm of the air conduction loudspeaker 16. In some embodiments, the distance between the bone conduction loudspeaker and the air conduction loudspeaker 16 may be greater than a threshold value to prevent the electromagnetic components of the bone conduction loudspeaker and the air conduction loudspeaker 16 from generating an electromagnetic field that affects the vibration output of both loudspeakers.The “distance between the bone conduction loudspeaker and the air conduction loudspeaker 16” described in the present disclosure refers to the minimum distance between the magnetic components of the bone conduction loudspeaker and the magnetic components of the air conduction loudspeaker 16. Fig. Figure 5(b) is a comparison diagram illustrating the effect of different distances between a bone conduction loudspeaker and the air conduction loudspeaker 16 on a magnetic field of a coil according to some embodiments of the present disclosure. As in Fig. As shown in Figure 5(b), when the air-conducting loudspeaker 16 is magnetized to the right, the average magnetic field strength at coil 1, located above transducer 12, increases, while the average magnetic field strength at coil 2, located below transducer 12, decreases. Fig. 5(a) shown, and the magnet arrangement 1231 in the transducer 12 is magnetized upwards. As the distance between the transducer 12 of the bone conduction loudspeaker and the air conduction loudspeaker 16 increases, the coils 1 and 2 tend to be in a position with no magnets on their side. Thus, the greater the distance between the transducer 12 of the bone conduction loudspeaker and the air conduction loudspeaker 16, the less influence there is on the magnetic field of the coils in the transducer 12. To reduce the influence of the electromagnetic field generated between the electromagnetic components of the bone conduction loudspeaker and the air conduction loudspeaker 16 on the magnetic field in the coils, in some embodiments the distance between the bone conduction loudspeaker and the air conduction loudspeaker 16 can be greater than 0.3 mm.For example, the distance between the bone conduction loudspeaker and the air conduction loudspeaker can be greater than 0.4 mm.

[0038] To prevent the accelerometer from being affected by the vibration of the transducer 12 when measuring the acceleration of the vibrating plate 13, the vibration direction of the transducer 12 can in some cases be approximately perpendicular to the vibration-sensitive end of the accelerometer.

[0039] It should be noted that if the electronic component is a vibration-sensitive component such as an air-conducting loudspeaker or an accelerometer, the vibration direction of the vibration-sensitive component should be approximately perpendicular to the vibration direction of the transducer 12 in order to avoid the vibration-sensitive component being affected by the vibration of the transducer.The phrase “the vibration direction of the vibration-sensitive component is approximately perpendicular to the vibration direction of the transducer 12,” mentioned in the present disclosure, refers to the fact that, if the vibration-sensitive component is an air-conducting loudspeaker, the vibration direction of the transducer 12 is approximately perpendicular to the vibration direction of the diaphragm of the air-conducting loudspeaker; and if the vibration-sensitive component is an accelerometer, the vibration direction of the transducer 12 is approximately perpendicular to the vibration-sensitive end of the accelerometer. If the electronic component is a non-vibration-sensitive component such as a battery or a printed circuit board, the battery or the printed circuit board can be arranged at any location within the housing 11 to achieve an integrated design of the acoustic playback device 100.

[0040] In some embodiments, the electronic component can include both the vibration-sensitive and the non-vibration-sensitive components, and the vibration-sensitive component can be arranged approximately perpendicular to the vibration direction of the transducer 12. For example, in some embodiments, the electronic component includes a vibration-sensitive accelerometer and a non-vibration-sensitive circuit board. The accelerometer is mounted on the circuit board and housed within the loudspeaker 10 to achieve integration of the acoustic playback device. In this case, the accelerometer can be arranged approximately perpendicular to the vibration direction of the transducer 12.

[0041] Fig. Figure 6 is a schematic diagram showing the construction of the converter 12 according to some embodiments of the present disclosure. Fig. Figure 7(a) is an exploded view showing the converter 12 according to some embodiments of the present disclosure. The Fig. 6 and Fig. 7(a) The converter 12 shown can be used in each of the diagrams shown in the diagram. Fig. Speakers 10 shown in 2(a) to 5(a) are used. As shown in the Fig. 6 and Fig. As shown in Figure 7(a), the transducer 12 can comprise a vibrating plate 122, a magnetic circuit system 123, and a coil 124. The magnetic circuit system 123 can comprise a magnet assembly 1231 and a magnetically conductive cover 1232. The magnet assembly 1231 can comprise a magnet 1233, as well as a first magnetic plate 1234 and a second magnetic plate 1235, which are located on opposite sides of the magnet 1233 in the vibration direction of the transducer 12. In some embodiments, the magnetically conductive cover 1232 can be arranged about an axis outside the magnet assembly 1231. The coil 124 can be located in a magnetic field region of the magnet assembly 1231.In some embodiments, the coil 124 can extend into a magnetic gap formed between the magnetically conductive cover 1232 and the magnet arrangement 1231 along the vibration direction of the transducer 12, and the magnetically conductive cover 1232 is encased on an outer surface of the coil 124. In some embodiments, an inner wall of the magnetically conductive cover 1232 can be in close contact with the outer wall of the coil 124. In some embodiments, the vibration plate 122 can comprise a first vibration plate 125 and a second vibration plate 126. The first vibrating plate 125 elastically supports the magnet arrangement 1231 from one side of the first magnet plate 1234, which is facing away from the second magnet plate 1235, and the second vibrating plate 126 elastically supports the magnet arrangement 1231 from one side of the second magnet plate 1235, which is facing away from the first magnet plate 1234.For example, an edge region 1253 of the first vibration plate 125 is connected to one end of the magnetically conductive cover 1232 along the vibration direction of the transducer 12, and an edge region 1263 of the second vibration plate 126 is connected to the other end of the magnetically conductive cover 1232 along the vibration direction of the transducer 12.

[0042] In some embodiments, to facilitate the assembly of the supply wires of the coil 124, so that the input and output of the coil 124 are located at the same position on the magnetically conductive cover 1232, the number of coil windings along the radial direction of the transducer 12 can be uniform. For example, the number of radial coil windings can be 2, 4, 6, 8, etc. As shown in Fig. As shown in Figure 6, the radial direction of the transducer 12 is a direction perpendicular to an axis (or the vibration direction) of the transducer 12.

[0043] In some embodiments, the coil 124 can comprise a first coil 1241 and a second coil 1242. In some embodiments, the first coil 1241 and the second coil 1242 can be arranged along the vibration direction of the transducer 12. The first coil 1241 and the second coil 1242 are connected in series or in parallel. When the first coil 1241 and the second coil 1242 are connected in series or in parallel, an input position and an output position of each coil are located at the same position on the magnetically conductive cover 1232, which facilitates the assembly of the lead wires of the first coil 1241 and the second coil 1242. The input position and the output position of the first coil 1241 can both be located at the same position on the magnetically conductive cover 1232, and the input and output positions of the second coil 1242 can both be located at the same position on the magnetically conductive cover 1232.For example, the input position of the first coil 1241, the output position of the first coil 1241, the input position of the second coil 1242, and the output position of the second coil 1242 can all be located at a central position of the magnetically conductive cover 1232 (e.g., along the direction perpendicular to the vibration direction of the transducer 12, the center of the magnetically conductive cover 1232). In some embodiments, the winding directions of the first coil 1241 and the second coil 1242 can be opposite, or the current directions in the first coil 1241 and the second coil 1242 can be opposite. Under the driving force of the double coils (i.e., the coil 124 comprises the first coil 1241 and the second coil 1242), the transducer 12 oscillates relative to each other, which can increase the vibration amplitude of the transducer 12 compared to a single voice coil.In some embodiments, a lower high-frequency impedance can be achieved by using a double-coil structure. Fig. Figure 7(b) is a comparison diagram showing the impedance between the transducer 12 with single-coil and double-coil structures according to some embodiments of the present disclosure. As in Fig. As shown in Figure 7(b), the high-frequency impedance of the double coil is lower compared to the single coil structure.

[0044] In some embodiments, an impedance that is too low leads to an increase in current at the same battery voltage, which not only consumes more power but also reduces the battery's lifespan for the same capacity. Conversely, if the battery cannot supply the increased current, clipping distortion occurs. Conversely, an impedance that is too high leads to a decrease in current at the same battery voltage, resulting in reduced sensitivity and lower volume. To achieve a balance between battery life, distortion, sensitivity, and volume, the total DC impedance of the coil 124 can be in the range of 6 Ω to 10 Ω. In some embodiments, the design of the first coil 1241 and the second coil 1242 in the converter 12 can be based on the following requirements:

[0045] First: To ensure that the total DC impedance of coil 124 (consisting of the first coil 1241 and the second coil 1242) is within a range of 6 Ω to 10 Ω, the DC impedance of a single coil (either the first coil 1241 or the second coil 1242) can vary depending on the connection method (series or parallel). For example, to achieve a total DC impedance of 8 Ω for coil 124, the DC impedance of each individual coil (either the first coil 1241 or the second coil 1242) should be 4 Ω when the two coils are connected in series, and 16 Ω when the two coils are connected in parallel.

[0046] Secondly, to minimize the overall weight of the loudspeaker 10, the volume and mass of the magnetically conductive cover 1232 can be reduced by adhering the inner wall of the magnetically conductive cover 1232 to the outer wall of the coil 124 (including the first coil 1241 and the second coil 1242). While ensuring that the distance between the first coil 1241 and the second coil 1242 along the vibration direction of the transducer 12 is within a range of 1.5 mm to 2 mm, the coil 124 (the first coil 1241 and the second coil 1242) can be designed to be "slim" by increasing its axial height and decreasing its radial width.This leads to a corresponding reduction in the inner diameter of the magnetically conductive cover 1232 and subsequently to a reduction in the outer diameter while maintaining the thickness of the magnetically conductive cover 1232, which in turn reduces the mass of the magnetically conductive cover 1232 and the overall weight of the loudspeaker 10. In some embodiments, the shape of the coil 124 (including the first coil 1241 and the second coil 1242) can be "slim" by designing parameters such as wire diameter, radial coil windings, and axial positions of the coil 124 to meet these requirements. In some embodiments, to achieve a "slim" shape of the coil 124 (the first coil 1241 and the second coil 1242), the ratio of the axial height to the radial width of the first coil or the second coil must not be less than 3.For example, the ratio of the axial height to the radial width of the first coil or the second coil cannot be less than 3.5.

[0047] Thirdly: Since the axial height of the transducer 12 is primarily determined by the size of the internal magnet arrangement 1231, the axial height of a single coil (the first coil 1241 and / or the second coil 1242) can be within a range of less than 2.85 mm to meet the size requirements of the transducer 12 (e.g., if the acoustic playback device 100 is a headset, to ensure that the height of the loudspeaker 10 in the headset is within a range of less than 5.7 mm). For example, the axial height of a single coil (the first coil 1241 and / or the second coil 1242) can be approximately 2 mm.

[0048] To meet the above requirements, in some embodiments the first coil 1241 and the second coil 1242 can be connected in series. To ensure that the total DC impedance of coil 124 is within a range of 6 Ω to 10 Ω, the DC impedance of the first coil 1241 and / or the second coil 1242 can be within a range of 4 Ω ± 1 Ω. For example, to achieve a total DC impedance of coil 124 within a range of 7 Ω to 9 Ω, the DC impedance of the first coil 1241 and / or the second coil 1242 can be within a range of 3.5 Ω to 4.5 Ω. As a further example, to achieve a total DC impedance of coil 124 within a range of 8 Ω ± 0.8 Ω, the DC impedance of the first coil 1241 and / or the second coil 1242 can be within a range of 4 Ω ± 0.4 Ω.In some embodiments, the wire diameter of the first coil 1241 and / or the second coil 1242 can be in a range of 0.11 mm - 0.13 mm.

[0049] To meet the above requirements, the first coil 1241 and / or the second coil 1242 can, in some embodiments, have one of the following characteristics: a wire diameter of 0.11 mm, 2 to 6 radial coil windings, and 8 to 20 axial layers; a wire diameter of 0.12 mm, 2 to 6 radial coil windings, and 9 to 20 axial layers; or a wire diameter of 0.13 mm, 2 to 6 radial coil windings, and 10 to 22 axial layers. For example, the wire diameter of the first coil 1241 and / or the second coil 1242 can be 0.11 mm, with 3 to 5 radial coil windings and 12 to 20 axial layers. Another example is a wire diameter of 0.12 mm with 3 to 5 radial coil windings and 14 to 20 axial layers. Another example is a wire diameter of 0.13 mm with 3 to 4 radial coil windings and 15 to 22 axial layers.

[0050] In some embodiments, the relationship between the wire diameter, the radial coil windings, the axial positions and the DC resistance of each coil connected in series (the first coil 1241 and / or the second coil 1242) is shown in Table 1. Table 1 Drahtdurchmessermm RadialeSpulenwicklungen Axiale Lagen GleichstromwiderstandΩ 0,11 4 12 4,00 0,11 4 13 4,33 0,11 5 11 3,66 0,12 4 14 3,93 0,12 4 15 4,21 0,13 4 17 4,08 0,13 4 18 4,32 0,13 4 16 3,84

[0051] To keep the DC resistance of a single coil (the first coil 1241 or the second coil 1242) within a range of 4 Ω ± 1 Ω according to Table 1, while maintaining a uniform number of radial coil windings, the exemplary wire diameter of the first coil 1241 and / or the second coil 1242 can be 0.11 mm, with 4 radial coil windings and 12 axial layers. Under this condition, the DC resistance of the first coil 1241 and / or the second coil 1242 is 4 Ω. Another example: The wire diameter can be 0.12 mm, with 4 radial coil windings and 14 axial layers. In this case, the DC resistance of the first coil 1241 and / or the second coil 1242 is 3.93 Ω. As another example, the wire diameter can be 0.12 mm, with 4 radial coil windings and 15 axial layers. The DC resistance of the first coil 1241 and / or the second coil 1242 is 4 Ω.Finally, the wire diameter can be 0.13 mm, with 4 radial coil windings and 18 axial layers. In this case, the DC resistance of the first coil 1241 and / or the second coil 1242 is 4.08 Ω.

[0052] In some embodiments, the first coil 1241 and the second coil 1242 can be connected in parallel. To ensure that the total DC resistance of the coil 124 is within a range of 6 Ω to 10 Ω, the DC resistance of the first coil 1241 and / or the second coil 1242 should each be within a range of 12 Ω to 20 Ω. For example, to meet the requirement that the total DC resistance of the coil 124 be within a range of 8 Ω ± 0.8 Ω, the DC resistance of the first coil 1241 and / or the second coil 1242 can be within a range of 16 Ω ± 1.6 Ω. In some embodiments, the wire diameter in the first coil 1241 and the second coil 1242 can be within a range of 0.07 mm to 0.08 mm.

[0053] To meet the above requirements, in some embodiments the radial coil windings of the first coil 1241 and / or the second coil 1242 can have 4 to 8 turns and the axial layers 16 to 22 layers. For example, the radial coil windings of the first coil 1241 and / or the second coil 1242 can have 4 to 6 turns, and the axial layers can be 17 to 20 layers.

[0054] To keep the DC resistance of a single coil (the first coil 1241 or the second coil 1242) within a range of 16 Ω ± 1.6 Ω while maintaining a consistent number of radial coil windings, Table 2 specifies the wire diameter, radial coil windings, axial positions, and DC resistance of exemplary single coils (the first coil 1241 and / or the second coil 1242) connected in parallel. For example, the wire diameter of the single coils connected in parallel (the first coil 1241 and / or the second coil 1242) can be 0.08 mm, with 6 radial coil windings and 17 axial positions, resulting in a DC resistance of 16.16 Ω. Another example: The wire diameter can be 0.07 mm, with 4 radial coil windings and 20 axial layers, which corresponds to a DC resistance of 16.27 Ω. Table 2 Drahtdurchmessermm RadialeSpulenwicklungen Axiale Lagen GleichstromwiderstandΩ 0,08 6 17 16,16 0,07 4 20 16,27

[0055] In some embodiments, such as in Fig. 4 or Fig. As shown in Figure 6, the coil 124 is wound around an axis parallel to the direction of vibration and is located outside the magnet assembly 1231, while the magnetically conductive cover 1232 is wound around the axis and located outside the coil 124. A magnetic gap A1 is located between the coil 124 and the magnet assembly 1231. The magnetic gap A1 refers specifically to a gap formed between the inner wall of the coil 124 and the outer wall of the magnet 1233 in the magnet assembly 1231. An excessively large magnetic gap A1 can reduce the magnetic field strength, while an excessively small magnetic gap A1 can impede processing. Therefore, in some embodiments, the radial width of the magnetic gap A1 can be in the range of 0.25 mm to 0.35 mm to balance both the magnetic field strength and processability.For example, the magnetic gap A1 can be in a range of 0.27 mm to 0.33 mm. Another example: The magnetic gap A1 can be in a range of 0.29 mm to 0.31 mm. Yet another example is that the magnetic gap A1 between the coil 124 and the magnet arrangement 1231 can be 0.3 mm. In some embodiments, after selecting a magnet 1233 of a suitable size that meets the requirements for the width of the magnetic gap A1, the radial elasticity of the vibratory plate (such as the first vibratory plate 125 and the second vibratory plate 126) can be designed to meet the conditions necessary to resist the attractive force of the magnet 1233.

[0056] To prevent a reduction in magnetic field strength due to magnetic saturation of the magnetically conductive cover 1232 in some embodiments, the thickness of the magnetically conductive cover 1232 in the radial direction of the transducer 12 must not be too thin. In some embodiments, the thickness of the magnetically conductive cover 1232 in the radial direction of the transducer 12 cannot be less than 0.3 mm. However, an excessively thick magnetically conductive cover 1232 can increase the thickness of the transducer 12, so the thickness of the magnetically conductive cover 1232 must not be too thick. Therefore, the thickness of the magnetically conductive cover 1232 in the radial direction of the transducer can be in the range of 0.3 mm to 1 mm, taking into account both weight reduction and the avoidance of magnetic saturation. For example, the thickness of the magnetically conductive cover 1232 can be in the range of 0.4 mm to 0.9 mm.As another example, the thickness of the magnetically conductive cover 1232 can be in a range of 0.5 mm to 0.8 mm. In some embodiments, as in . Fig. As shown in Figure 7(a), the magnetically conductive cover 1232 can have a weight-reducing structure 1232a to further reduce the mass of the transducer 12 (and thus the mass of the loudspeaker 10). The weight-reducing structure 1232a can comprise a weight-reducing slot or hole in the magnetically conductive cover 1232. The weight-reducing slot or hole can have any shape or configuration. For example, the weight-reducing slot can be a through slot or a recess with any cross-section in the magnetically conductive cover 1232. Another example: The weight-reducing slot can be a circular groove opening on the inner wall of the magnetically conductive cover 1232.In some embodiments, the weight-reducing slot can be a rectangular through-slot that penetrates the side walls of the magnetically conductive cover 1232 and extends to an end face of the magnetically conductive cover 1232 along the direction of vibration. Fig. 7(c) is a partially schematic representation of the cylindrical magnetically conductive cover 1232 according to some embodiments of the present disclosure; Fig. Figure 7(d) is a schematic representation of the shell-shaped magnetically conductive cover 1232 according to some embodiments of the present disclosure. As in Fig. As shown in Figure 7(c), the weight-reducing structure 1232a can include a weight-reducing hole that is open on the side walls of the cylindrical magnetically conductive cover 1232. As shown in Fig. As shown in Figure 7(d), the weight-reducing structure 1232a can include a weight-reducing hole that is open on the side walls and / or the bottom of the shell-shaped magnetically conductive cover 1232.

[0057] Fig. Figure 8 is a comparison diagram showing frequency response curves when the magnetically conductive cover 1232 is slotted and unslotted. As in Fig. As shown in Figure 8, the horizontal axis represents the frequency (Hz), the vertical axis the frequency response (dB), curve 81 represents the frequency response curve of the converter 12 without slots, and curve 82 represents the frequency response curve of the converter 12 with slots. As shown in Fig. As shown in Figure 8, the frequency corresponding to the resonance peak of curve 82 is higher than that of curve 81. Therefore, after the slots are cut, the mass of the magnetically conductive cover 1232 decreases, thereby reducing the mass of the transducer 12, which in turn increases the resonance frequency of the transducer 12. Simultaneously, the frequency response of the transducer 12 with slots after the resonance frequency (approximately 100 Hz) is greater than that of the transducer 12 without slots at the same frequency, thus improving the sound quality of the transducer 12.

[0058] In some embodiments, the shape of the outer diameter of the magnetically conductive cover 1232 can be rectangular, elliptical, circular, racetrack-shaped, polygonal, etc. As in Fig. As shown in Figure 7(a), the outer diameter shape of the magnetically conductive cover 1232 can, for example, be racetrack-shaped, wherein the length of the corresponding equivalent rectangle is less than 20 mm and the width is less than 12 mm. Another example: The length and width of the equivalent rectangle corresponding to the magnetically conductive cover 1232 are 18.1 mm and 10.1 mm, respectively. The racetrack shape mentioned in the present disclosure generally refers to a closed loop formed by connecting the two ends of two arcs with the two ends of two straight lines. The racetrack shape can also, for example, be a rounded rectangle in which all four right angles of a rectangle are replaced by rounded corners. The length / width of the equivalent rectangle refers to the length / width of the rectangle corresponding to the racetrack shape (e.g.,the shape that results when the four rounded corners of the racetrack shape are replaced by right angles).

[0059] In some embodiments, the magnetic assembly 1231 may comprise a magnet 1233 and a magnetic circuit board arranged on one side of the magnet 1233 in the vibration direction of the transducer 12. If the magnetic circuit board is too thin, it tends to become magnetically saturated, and the magnetic field strength at the coil position decreases accordingly. However, if the magnetic circuit board is too thick due to limitations on the overall volume of the magnetic assembly 1231, this can easily result in the magnet 1233 being too thin, leading to a low magnetic field strength. Therefore, to increase the magnetic field strength and avoid magnetic saturation, the ratio between the thickness of the magnetic circuit board and the thickness of the magnet 1233 can be in the range of 0.05 to 0.35. For example, the ratio of the thickness of the magnetic circuit board to the thickness of the magnet 1233 can be in the range of 0.15 to 0.3.In some embodiments, the magnetic circuit board can comprise a first magnetic circuit board 1234 and a second magnetic circuit board 1235. The first magnetic circuit board 1234 is located on one side of the magnet 1233 in the vibration direction of the transducer 12, and the second magnetic circuit board 1235 is located on the other side of the magnet 1233 in the vibration direction of the transducer 12. The ratio of the thickness of the first magnetic circuit board 1234 or the second magnetic circuit board 1235 (hereinafter referred to as the magnetic circuit board) to the thickness of the magnet 1233 is in the range of 0.05 to 0.35. In some embodiments, the thickness of the magnetic circuit board (the first magnetic circuit board 1234 or the second magnetic circuit board 1235) can be in the range of 0.5 mm to 1 mm to increase the magnetic field strength and avoid magnetic saturation.For example, the thickness of the magnetic circuit board (the first magnetic circuit board 1234 or the second magnetic circuit board 1235) can be in a range of 0.6 mm to 0.7 mm.

[0060] In some embodiments, to facilitate the assembly and positioning of the magnet 1233 with the magnetically conductive plate (the first magnetically conductive plate 1234 and / or the second magnetically conductive plate 1235) and to reduce the mass of the transducer 12 (further reducing the overall mass of the acoustic playback device 100), holes may be drilled in the magnet 1233 and / or the magnetically conductive plate (the first magnetically conductive plate 1234 and / or the second magnetically conductive plate 1235). For example, as in Fig. As shown in Figure 7(a), the magnet 1233 is provided with a first hole 1233a, and the magnetically conductive plate is provided with a second hole 1234a, which can be positioned accordingly with the first hole 1233a to facilitate the assembly and positioning of the magnet 1233 with the magnetically conductive plate (the first magnetically conductive plate 1234 and / or the second magnetically conductive plate 1235).

[0061] In some embodiments, the number of second holes 1234a on the magnetically conductive plate can be at least two to improve the accuracy of assembly. Accordingly, the number of first holes 1233a on the magnet 1233 can also be at least two, each corresponding to a second hole 1234a. Fig. Figures 9(a) to 9(c) are top views showing the magnetically conductive plate according to some embodiments of the present disclosure. As in Fig. As shown in Figure 9(a), the magnetically conductive plate has a rounded rectangular structure, and two second holes 1234a are arranged along a longitudinal direction of the magnetically conductive plate (as in Figure 9(a)). Fig. 9(a) shown). In some embodiments, the two second holes 1234a are arranged on the centerline along the longitudinal direction of the magnetic conductive plate. As shown in Fig. As shown in 9(b), the magnetically conductive plate has a rounded rectangular structure, and two second holes 1234a are arranged along a diagonal direction of the magnetically conductive plate. As shown in Fig. As shown in Figure 9(c), the magnetically conductive plate has a rounded rectangular structure, and second holes 1234a are placed near each of the four rounded corners.

[0062] Fig. Figure 10 is a comparison diagram showing frequency response curves when a magnetically conductive plate is perforated and unperforated according to some embodiments of the present disclosure. Fig. Figure 11 is a comparison diagram showing frequency response curves when a magnetically conductive plate is perforated and unperforated according to some embodiments of the present disclosure. Fig. 10 is curve 101, the frequency response curve without holes on the magnetically conductive plate; curve 102 is the frequency response curve with two holes along the center line in the longitudinal direction of the magnetically conductive plate (as in Fig. 9(a) shown), curve 103 is the frequency response curve with two holes along the diagonal of the magnetically conductive plate (as in Fig. 9(b) shown), and curve 104 is the frequency response curve with four holes along the diagonal of the magnetically conductive plate (as in Fig. 9(c) shown). As in Fig. As shown in Figure 10, a comparison of curves 102 and 103 reveals that the frequency response curves are almost identical when two holes are drilled longitudinally along the center line and when two holes are drilled diagonally. A comparison of curves 103 and 104 shows that the frequency response decreases slightly with an increase in the number of holes on the diagonal, but the decrease is almost 0.5 dB. Comparing curve 101 with other curves (curve 102, 103, or 104), a slight decrease in frequency response compared to the case where no holes are drilled in the magnetically conductive plate is observed, but the decrease is also almost 0.5 dB, indicating that the effect of drilling holes on the frequency response is not significant.From the point of view of weight reduction and facilitating assembly and positioning, however, drilling holes reduces the mass of the transducer 12 and facilitates the assembly and positioning of the magnet 1233 with the magnetically conductive plate (the first magnetically conductive plate 1234 and / or the second magnetically conductive plate 1235).

[0063] In Fig. Curve 1111 is a BL value curve without holes on the magnetically conductive plate; curve 1112 is a BL value curve with two holes along the centerline in the longitudinal direction of the magnetically conductive plate (as in Fig. 9(a)), Curve 1113 is a BL value curve with two holes along the diagonal of the magnetically conducting plate (as in Fig. 9(b)) shown) and curve 1114 is a BL value curve with four holes along the diagonal of the magnetically conducting plate (as in Fig. 9(c)) shown). The BL value reflects the electromagnetic properties and refers to the product of the magnetic field strength and the length of a coil wire. As in Fig. As shown in Figure 11, a comparison of curves 1112 and 1113 reveals that the BL value curves are almost identical when two holes are drilled longitudinally along the centerline and two holes are drilled diagonally. A comparison of curves 1113 and 1114 shows that the BL value decreases slightly with an increasing number of holes on the diagonal. Comparing curve 1111 with other curves (curve 1112, 1113, or 1114), the BL value decreases slightly compared to the case where no holes are drilled on the magnetically conductive plate. However, this decrease is almost in the range of 0.05 Tm, so the influence of drilling holes on the BL value is not significant.From the point of view of weight reduction and facilitating assembly and positioning, however, drilling holes reduces the mass of the transducer 12 and facilitates the assembly and positioning of the magnet 1233 with the magnetically conductive plate (the first magnetically conductive plate 1234 and / or the second magnetically conductive plate 1235).

[0064] In some embodiments, the position of the second hole 1234a on the magnetic circuit board has a significant influence on the BL value of the transducer 12. Using the example of two second holes 1234a placed on the centerline of the magnetic circuit board along its length, a comparison is made. Fig. 12 the BL value curves when a distance between the second hole and a center of the magnetic circuit board varies. As in Fig. As shown in Figure 12, curve 1211 represents a BL value curve when the second hole 1234a is 5 mm from the center of the magnetic circuit board, curve 1212 represents a BL value curve when the distance is 5.5 mm, curve 1213 represents a BL value curve when the distance is 6 mm, and curve 1214 represents a BL value curve when the distance is 6.5 mm. With the same coil offset (e.g., 0 mm), curves 1211, 1212, 1213, and 1214 decrease sequentially, with curve 1214 being significantly lower than the other three curves. The center of the magnetic circuit board refers to its geometric center. As shown in Figure 12, the center of the magnetic circuit board is defined as its geometric center. Fig. As can be seen in Figure 12, the BL value of the transducer 12 decreases more sharply the further the second hole 1234a is from the center of the magnetic circuit board and towards the edge. Therefore, the second hole 1234a should be located as far as possible from the edge of the magnetic circuit board. It should be noted that the distance between the second hole 1234a and the center of the magnetic circuit board refers to the distance between the center of the second hole and a geometric center of the magnetic circuit board. In some embodiments, to increase the BL value of the transducer 12, the ratio between the opening area of ​​the second hole 1234a and the area of ​​the magnetic circuit board on which the second hole is located is less than 36%, without restrictions on the shape and position of the opening. It should be noted that a distance between an edge of the second hole 1234a and an edge of the magnetic circuit board in Fig. Figure 9(a) illustrates this. A straight line LA is formed by extending the line connecting the center point W2 of the second hole 1234a and the geometric center W1 of the magnetic circuit board towards the edge of the magnetic circuit board. Point B is the intersection of line LA with the edge of the magnetic circuit board, while point C is the intersection of line LA with the edge of the second hole 1234a near point B. The distance between the edge of the second hole 1234a and the edge of the magnetic circuit board corresponds to the distance between points B and C on line LA. In some embodiments, the distance between the edge of the second hole 1234a and the edge of the magnetic circuit board may be greater than 0.2 mm, which can prevent the second hole from being too close to the edge and reducing its structural strength.At the same time, this reduces the effect of the second hole on the magnetic field strength, ensuring that the sensitivity of the loudspeaker does not decrease significantly.

[0065] Fig. Figure 13 is a comparison diagram showing frequency response curves when the second hole 1234a has different diameters according to some embodiments of the present disclosure. As in Fig. As shown in Figure 13, curve 1311 represents a frequency response curve when the diameter of the second hole 1234a is 1 mm, curve 1312 represents a frequency response curve when the diameter of the second hole 1234a is 1.5 mm, and curve 1313 represents a frequency response curve when the diameter of the second hole 1234a is 2 mm. As the diameter of the second hole 1234a increases, the frequency response of the transducer 12 decreases accordingly, with a decrease of approximately 0.5 dB per 0.5 mm increase in diameter. Fig. Figure 14(a) is a comparison diagram illustrating the BL value curves when the second hole 1234a has different diameters according to some embodiments of the present disclosure. As in Fig. As shown in Figure 14(a), curve 141 represents a BL value curve when the diameter of the second hole 1234a is 1 mm, curve 142 represents a BL value curve when the diameter of the second hole 1234a is 1.5 mm, and curve 143 represents a BL value curve when the diameter of the second hole 1234a is 2 mm. As the diameter of the second hole 1234a increases, the BL value decreases accordingly. Thus, the larger the diameter of the second hole 1234a, the smaller the frequency response and the BL value. However, due to the influence of manufacturing accuracy and structural strength, the diameter of the second hole 1234a cannot be too small or too large.To prevent the corresponding positioning column from being too thin due to the small diameter of the second hole 1234a, which would lead to insufficient structural strength and excessive demands on processing accuracy, and to prevent the frequency response and BL value from being reduced due to an excessively large diameter, the diameter of the second hole 1234a can be in a range of 1.5 mm to 2.5 mm. For example, the diameter of the second hole 1234a can be within a range of 1.8 mm to 2.3 mm. In some embodiments, the ratio between the opening area of ​​the second hole 1234a and the area of ​​the magnetic circuit board on which the second hole is located is less than 36%, in order to compensate for the magnetic field strength and the sensitivity of the transducer 12.

[0066] In some embodiments, by specifying an even number of coils 124 along the radial direction of the transducer 12, the input and output positions of the first coil 1241 or the second coil 1242 are arranged at the same position on the magnetically conductive cover 1232, so that the inner wall of the magnetically conductive cover 1232 is in close contact with the outer wall of the coil 124, thereby reducing the mass of the transducer 12 (and consequently the mass of the loudspeaker 10). Furthermore, by shaping the coil 124 (the first coil 1241 and the second coil 1242) into an elongated form and selecting suitable parameters for the coil 124, the inner diameter of the magnetically conductive cover 1232 can be reduced to further reduce the mass of the transducer 12 (and consequently the mass of the loudspeaker 10).In some embodiments, the mass of the transducer 12 (and consequently the mass of the loudspeaker 10) can be reduced by introducing a weight-reducing slot into the magnetically conductive cover 1232 or by drilling a hole in the magnet 1233 and / or the magnetically conductive plate (the first magnetically conductive plate 1234 and / or the second magnetically conductive plate 1235). In some embodiments, the mass m of the loudspeaker 10 after the weight reduction can be in the range of 2 g to 5 g. For example, the mass m of the loudspeaker 10 can be in the range of 3.8 g to 4.5 g.

[0067] Fig. Figure 14(b) is a comparison diagram showing the acceleration curves of the transducer 12 within a mass range of 2g to 5g according to some embodiments of the present disclosure. The diagrams AI represent different embodiments in which the mass of the transducer 12 lies within a range of 2g to 5g under different conditions, such as different wire diameters of the coils (of the first coil and the second coil), different numbers of radial coil windings and axial layers, different products of radial coil windings and axial layers, different methods of connecting coils in series or parallel, etc. As shown in Fig. As shown in Figure 14(b), after weight reduction (with the mass of the transducer 12 in the range of 2 g–5 g) according to some embodiments of the present disclosure, the transducer 12 exhibits an acceleration range of 70 dB–110 dB at 1 kHz when excited by a test voltage. The measurement method of the Fig. The acceleration curve shown in 14(b) comprises: exciting the transducer 12 shown in the embodiments of the present disclosure under a test voltage to generate vibrations, measuring the displacement generated by the transducer 12 which drives the vibrating disk 13 by laser testing, normalizing the displacement by data processing (e.g. dividing the displacement in the corresponding frequency band by the corresponding test voltage) and comparing the normalized displacement with 1 mm / s 2, to obtain the dB value of the acceleration. In some embodiments, the sensitivity of the transducer 12 can be improved by adjusting it to a suitable acceleration range, thereby achieving the goal of improving the sound quality of the loudspeaker 10. Even if the amplitude of the BL value curve decreases after weight reduction, the acceleration of the frequency response is improved. The in Fig. The acceleration curve shown in 14(b) is determined by measuring the vibration acceleration of the vibration disc 13 with the fastening element 20 fixed.

[0068] In some embodiments, the vibratory plate 122 can be arranged such that it connects the magnetically conductive cover 1232 and the magnet assembly 1231 to elastically support the magnet assembly 1231. In some embodiments, the vibratory plate 122 can comprise a first vibratory plate 125 and a second vibratory plate 126. As shown in Fig. As shown in Figure 7(a), the first vibratory plate 125 or the second vibratory plate 126 (hereinafter referred to as vibratory plate 122) can comprise a rim region 1253, a central region 1252, and several support rods 1251 connecting the rim region 1253 and the central region 1252. In some embodiments, the central region 1252 of the vibratory plate 122 (e.g., the first vibratory plate 125 or the second vibratory plate 126) can be connected to the magnet assembly 1231. For example, the central region 1252 of the first vibratory plate 125 is connected to the first magnetically conductive plate 1234 of the magnet assembly 1231, and the central region 1252 of the second vibratory plate 126 is connected to the second magnetically conductive plate 1235 of the magnet assembly 1231. In some embodiments, the central area 1252 may be provided with a through-hole (as in the Fig. 16(a)-16(b)), and a projecting column may be provided on the side of the magnetically conductive plate facing the central region 1252, thereby achieving a connection and fixation through the interaction of the projecting column and the through-hole. In some embodiments, the projecting column may be a hot-melt column that can fix the central region 1252 on the magnetically conductive plate by melting and deformation after insertion into the through-hole. In some embodiments, the outer contour of the edge region 1253 of the vibratory plate may have the shape of a racetrack, or the outer contour of the edge region 1253 may be rectangular, elliptical, or circular, etc. Compared to the use of a single vibratory plate, double vibratory plates (i.e.,, the vibration plate 122 includes the first vibration plate 125 and the second vibration plate 126) significantly increase the number of failure cycles, and the elastic support of the first vibration plate 125 and the second vibration plate 126 for the magnet arrangement 1231 reduces the vibration amplitude of the moving parts in the converter 12.

[0069] In some embodiments, the multiple support rods 1251 of the vibrating plate 122 can have a zigzag bending structure to give the vibrating plate a predetermined coefficient of elasticity. Fig. Figures 15(a)-15(c) and 16(a)-16(b) are structural diagrams showing the vibratory plate 122 according to some embodiments of the present disclosure. Fig. Figures 15(a)-15(c) and 16(a)-16(b) show several embodiments of the vibratory plate and also several embodiments of the support rods. In some embodiments, the support rods 1251 of the vibratory plate can adopt several bending structures, as shown in Fig. Figures 15(a)-15(c) and 16(a)-16(b) show multiple bending structures and are connected to the edge region 1253 and the central region 1252 at both ends to give the vibratory plate a predetermined coefficient of elasticity and to prevent or reduce the rotational and / or oscillatory motion between the coil and the moving parts of the magnetic circuit system 123.

[0070] In some embodiments, referring to the Fig. 16(a) and Fig. In Figure 16(b), a through-hole 1252a is provided in the central area 1252 of the vibrating plate 122 for the insertion of a projecting column, which is placed on the magnetically conductive plate (the first magnetically conductive plate 1234 or the second magnetically conductive plate 1235), thereby achieving a connection and fixation through the interaction of the projecting column and the through-hole 1252a. Examples of connection methods include hot glue, bolts, etc.

[0071] To resist the magnetic attraction of the magnet arrangement 1231 and to prevent magnetic misalignment in the transducer 12, the stiffness of the vibrating plate 122 in any direction (hereinafter referred to as the radial direction) within the plane perpendicular to the vibration direction can be greater than a stiffness threshold. For example, the equivalent stiffness in the radial direction of the vibrating plate 122 can be greater than 4.7 × 10 4N / m, based on the width of the magnetic gap A1 and the magnetic attraction between the magnet arrangement 1231 and the magnetically conductive cover 1232. Another example: The equivalent stiffness in the radial direction of the vibrating plate 122 can be greater than 6.4 x 10 4 N / m. By optimizing the stiffness in the longitudinal and lateral directions of the elastic vibration plate 122 in the plane perpendicular to the direction of vibration, it can resist the magnetic attraction of the magnet arrangement 1231 and thus prevent a magnet misalignment in the transducer 12, which means that collisions between the coil and the moving parts of the magnetic circuit system 123 are avoided.

[0072] It should be noted that the transducer 12 provided in the present disclosure may comprise at least one vibration plate, and the at least one vibration transmission plate is connected between the magnet arrangement 1231 and the magnetically conductive cover 1232. The equivalent radial stiffness of the at least one vibration plate is greater than 4.7 x 10 4 N / m. The converter 12 can, for example, contain at least one vibration plate 122. As another example, the converter 12 can contain at least two vibration plates 122, namely a first vibration plate 125 and a second vibration plate 126. The equivalent radial stiffness of the first vibration plate 125 and the second vibration plate 126 can be greater than 4.7 × 10 4 N / m.

[0073] In some embodiments, the dimensional data of the vibratory plate 122 can be determined based on the requirements for its equivalent stiffness in the radial direction. In some embodiments, the ratio of a distance between a starting point and an end point of the support rod 1251 along the longitudinal direction of the vibratory plate 122 to the length of the support rod 1251 itself can be in a range of 0 to 1.2. The distance between the starting point and the end point of the support rod 1251 along the longitudinal direction of the vibratory plate 122 refers to a distance along the longitudinal direction of the vibratory plate 122 between a connection point of the support rod 1251 with the central region 1252 of the vibratory plate and a connection point of the support rod 1251 with the edge region 1253 of the vibratory plate. As in Fig. As shown in Figure 16(b), for example, the ratio of a distance SE between a starting point S and an end point E of the support rod 1251 along the longitudinal direction of the vibratory plate 122 to the total length of the curved support rod 1251 can be in a range of 0.7 to 0.85. In some embodiments, the ratio of the distance between the starting point and the end point of the support rod 1251 along a lateral direction of the vibratory plate 122 to the length of the support rod 1251 can be in a range of 0 to 0.5. The distance between the starting point and the end point of the support rod 1251 along the lateral direction of the vibratory plate 122 refers to a distance along the lateral direction of the vibratory plate 122 between the connection point of the support rod 1251 with the central region 1252 of the vibratory plate and the connection point of the support rod 1251 with the edge region 1253 of the vibratory plate. As in Fig. As shown in Figure 16(b), for example, the ratio of a distance S'E' between the starting point S and the end point E of the support rod 1251 along the width direction of the vibrating plate 122 to the total length of the curved support rod 1251 can be in a range of 0.15 - 0.35.

[0074] In some embodiments, the length of the support rod 1251 can range from 7 mm to 25 mm. In some embodiments, the thickness of the support rod along the axial direction of the transducer 12 (i.e., the thickness of the vibratory plate) can range from 0.1 mm to 0.2 mm. In some embodiments, the ratio between the thickness of the vibratory plate along the axial direction of the transducer 12 and the width of any support rod 1251 along a radial plane of the transducer 12 can range from 0.16 to 0.75. Exemplary ranges for the thickness-to-width ratio can be: 0.2 - 0.7, 0.26 - 0.65, 0.3 - 0.6, 0.36 - 0.55, or 0.4 - 0.5, etc. In some embodiments, the thickness of the first vibratory plate 125 can be in a range of 0.1 mm - 0.2 mm, and the width range of the support rod 1251 can be in a range of 0.25 mm - 0.5 mm.For example, the thickness of the first vibration plate 125 can be in a range of 0.1 mm - 0.15 mm and the width of the support rod 1251 can be in a range of 0.4 mm - 0.48 mm.

[0075] In some embodiments, the loudspeaker 10 may comprise an air conduction loudspeaker and a bone conduction loudspeaker (e.g., as in Fig. 4 or Fig. 5(a) shown). In some embodiments, a crossover point between bone conduction and air conduction can be located in a low to mid-frequency range (e.g., within a range of 400 Hz–500 Hz). Sounds above the crossover point are produced by the bone conduction loudspeaker, and sounds below the crossover point by the air conduction loudspeaker, thus preventing the bone conduction loudspeaker from vibrating at low frequencies and causing the user to experience significant vibrations. Furthermore, since the bone conduction loudspeaker exhibits a relatively flat frequency response curve some distance from its resonant peak frequency, the output distortion of the corresponding frequency band is low. Therefore, the resonant peak frequency of the bone conduction loudspeaker can be set below the crossover point. A certain distance may exist between the resonant peak frequency and the crossover point.In some embodiments, the peak resonance frequency of the transducer 12 can be less than 300 Hz.

[0076] In some embodiments, in order to reduce the resonance peak frequency of the transducer 12 to less than 300 Hz, a ratio range of a total axial (parallel to the vibration direction) elasticity coefficient k of the vibration plate 122 to the mass m of the transducer 12 can be defined as follows: km<(2π⋅300)2≈3.6×106Hz2. In some embodiments, the mass of the transducer 12 can comprise the sum of the masses of the magnetically conductive cover 1232, the coil 124, and the housing 11, or the sum of the masses of the air-conducting loudspeaker 16, the magnetically conductive cover 1232, the coil 124, and the housing 11. The unit of the elasticity coefficient k is N / m (newtons per meter), and the unit of mass m is g (grams).

[0077] In some embodiments, the mass m of the transducer 12 can be in a range of 2 g to 5 g in order to reduce the overall size and mass of the device and to improve sound quality. For example, the mass of the transducer 12 can be in a range of 2.2 g to 4.8 g.

[0078] In some embodiments, the total axial elasticity coefficient k of the vibrating plate 122 can be set to less than 18000 N / m based on the mass range of the transducer 12 and the ratio range of the total axial elasticity coefficient k of the vibrating plate 122 to the mass m of the transducer 12. In some embodiments, the vibrating plate 122 comprises a parallel connection of the first vibrating plate 125 and the second vibrating plate 126, as shown in Fig. Figure 4 illustrates this. In some embodiments, the axial elasticity coefficients k0 of the first vibratory plate 125 and the second vibratory plate 126 can be the same, and the axial elasticity coefficient k0 of each vibratory plate can be less than 9000 N / m. In some embodiments, the axial elasticity coefficients k0 of the first vibratory plate 125 and the second vibratory plate 126 can be different, but the total axial elasticity coefficient k provided by the first vibratory plate 125 and the second vibratory plate 126 is less than 18000 N / m.

[0079] By adjusting the mass range of the mass block connected by the double vibration plates, consisting of the first vibration plate 125 and the second vibration plate 126, and / or by adjusting the elasticity coefficients of the double vibration plates, the peak frequency of the bone conduction resonance can therefore be achieved at a maximum of 300 Hz. It should be noted that the mass of the mass block refers to the mass of all components that must be driven by the double vibration plates. In the Fig. In the embodiment shown in 2(a), the mass of the mass block is, for example, the total mass of the coil 124, the magnetic shield 1232, the support 121, the vibration disc 13, and the damping plate 14. As a further example, in the Fig. In the embodiment shown in Figure 3, the mass of the mass block comprises the total mass of the coil 124, the magnetically conductive cover 1232, the vibrating disc 13, and the housing 11. In the bone-to-air conduction loudspeaker embodiment, the mass of the mass block also includes the mass of the air conduction loudspeaker. In some embodiments, the mass of the mass block may also include the mass of other necessary connecting components.

[0080] By adjusting the mass range of the mass block connected by the double vibration plates, consisting of the first vibration plate 125 and the second vibration plate 126, and / or the elastic coefficients of the double vibration plates, the peak frequency of the bone conduction resonance can therefore be achieved at a maximum of 300 Hz. It should be noted that the mass of the mass block refers to the mass of all components that must be driven by the double vibration plates. In the Fig. In the embodiment shown in 2(a), the mass of the mass block is, for example, the total mass of the coil 124, the magnetically conductive cover 1232, the bracket 121, the vibrating disc 13, and the damping plate 14. As a further example, in the Fig. In the embodiment shown in Figure 3, the mass of the mass block comprises the total mass of the coil 124, the magnetically conductive cover 1232, the vibration disc 13, and the housing 11. In the bone-air loudspeaker embodiment, the mass of the mass block also includes the mass of the air-conducting loudspeaker. Furthermore, the mass of the mass block may also include the mass of other necessary connecting components.

[0081] Fig. Figures 17(a) to 17(g) are schematic diagrams showing the construction of the magnetic circuit system 123 in the form of a Halbach array according to some embodiments of the present disclosure. It should be noted that Fig. Figures 17(a) to 17(g) show the central cross-section of the magnetic circuit system 123 and are the right halves of two-dimensional, axially symmetric figures. The combination of Fig. In Figures 4, 6, and 17(a) to 17(g), the transducer 12 can comprise the magnetic circuit system 123 and the coil 124. The magnetic circuit system 123 can comprise a magnet assembly 1231 and a magnetically conductive cover 1232. The coil 124 can be wound around the outside of the magnet assembly 1231 parallel to the axis of the vibration direction, and the magnetically conductive cover 1232 can be wound around the outside of the coil 124 along the axis. In some embodiments, at least one of the magnets 1233 contained in the magnet assembly 1231, the magnetically conductive plate, or the magnetically conductive cover 1232 can contain multiple magnetic parts with different magnetization directions. In some embodiments, the magnet assembly 1231 and / or the magnetically conductive cover 1232 can contain multiple magnetic parts (e.g., magnets) with different magnetization directions.The multiple magnetic parts with different magnetization directions can form a Halbach array (e.g., as in the ). Fig. 17(a) to 17(g)). By a special arrangement of the array, the magnetic field can be concentrated on one side of the magnetic component 1231, thereby increasing the magnetic field strength at the coil 124.

[0082] In some embodiments, the magnet 1233, the magnetically conductive plate, or the magnetically conductive cover 1232 can have arrangements consisting of several magnetic parts with different magnetization directions. In some embodiments, the magnetization directions of the several magnetic parts rotate clockwise or counterclockwise on a surface parallel to the vibration direction of the transducer 12. As shown in Fig. As shown in Figure 17(a), the magnet 1233 and the magnetically conductive plate (the first magnetically conductive plate 1234 and / or the second magnetically conductive plate 1235) may not contain any magnetic sub-assemblies, whereas the magnetically conductive cover 1232 may contain three layers of magnetic parts arranged axially, with the magnetization directions of these layers extending radially outward, axially downward, and radially inward from top to bottom. As shown in Fig. As shown in Figure 17(b), the magnetically conductive cover 1232 and the magnet 1233 may not contain any magnetic sub-assemblies, whereas the magnetically conductive plate (the first magnetically conductive plate 1234 and / or the second magnetically conductive plate 1235) may contain four radially arranged magnetic parts, wherein the two magnetic parts in the top layer and the two magnetic parts in the bottom layer each contain two radially arranged magnetic parts. The magnetization directions of the two magnetic parts in the top layer are axially upward and radially outward from left to right, whereas the magnetization directions of the two magnetic parts in the bottom layer are axially upward and radially inward from left to right.In some embodiments, both the magnetically conductive plate (the first magnetically conductive plate 1234 and / or the second magnetically conductive plate 1235) and the magnetically conductive cover 1232 can have magnetic sub-assemblies. As shown in . Fig. As shown in 17(c), the arrangement of the magnetic parts of the magnetically conductive plate is similar to that in Fig. 17(b) shown, while the arrangement of the magnetic parts of the magnetically conductive cover 1232 is similar to that in Fig. Figure 17(a) shows that in some embodiments, the magnet 1233, the magnetically conductive plate and / or the magnetically conductive cover 1232 may have more magnetic sub-assemblies compared to the three-layer magnetic sub-assembly. As shown in Fig. As shown in Figure 17(d), the magnet 1233 and the magnetically conductive plate (the first magnetically conductive plate 1234 and / or the second magnetically conductive plate 1235) may not have magnetic sub-assemblies, whereas the magnetically conductive cover 1232 may contain five layers of magnetic sub-assemblies arranged axially, with the magnetization directions of these layers being axially upward, radially outward, axially downward, radially inward, and axially upward from top to bottom. In some embodiments, the magnet 1233 may be a hollow ring structure. As shown in Fig. As shown in Figure 17(e), the magnet 1233 can contain three layers of magnetic sections arranged axially, with the magnetization directions of these layers running radially outward from top to bottom, axially upward, and radially inward. As shown in Fig. As shown, the magnets 1233 can contain five layers of magnetic parts arranged axially, with the magnetization directions of these layers running from top to bottom, radially outward, axially upward, radially inward, and axially downward. As shown in Fig. As shown in Figure 17(g), the magnet 1233 can contain three layers of magnetic parts arranged axially, the magnetization directions of these layers being radially outward, axially upward, and radially inward from top to bottom, while the magnetically conductive cover 1232 can contain three layers of magnetic parts arranged axially, the magnetization directions of these layers being radially outward, axially downward, and radially inward from top to bottom. In some embodiments, the magnetization directions of at least two adjacent magnetic parts in the multiple magnetic parts can be perpendicular to each other.

[0083] Fig. Figure 18 is a comparison diagram showing BL value curves of the magnetic circuit system 123 with different magnetic arrangements according to some embodiments of the present disclosure. Fig. Figure 181 represents a BL value curve of the magnetic circuit system 123 without a magnetic segment arrangement, while curves 182-188 represent BL value curves of the magnetic circuit system 123 with magnetic segment arrangements, as shown in the Fig. Figures 17(a) to 17(g) are shown. As can be seen from Fig.As can be seen in Figure 18, the magnetic flux density is increased compared to an arrangement without magnetic segments when the magnetically conductive cover and / or the magnet arrangement has a magnetic segment arrangement. The increase in magnetic flux density is significant when the magnetically conductive cover has a magnetic segment arrangement, with an approximate increase of 12%. By configuring magnet 1233 as a hollow-ring magnetic segment arrangement, the magnetic flux density is still increased by about 6% compared to an arrangement without magnetic segments.

[0084] The possible advantageous effects of the embodiments described in the present disclosure include, among others: (1) by specifying an even number of coils 124 along the radial direction of the transducer 12, the input and output positions of the first coil 1241 or the second coil 1242 are located at the same position of the magnetically conductive cover 1232, thereby allowing the inner wall of the magnetically conductive cover 1232 to be adapted to the outer wall of the coil 124 and reducing the mass of the transducer 12 (and consequently the mass of the loudspeaker 10); (2) by shaping the coil 124 (first coil 1241 and second coil 1242) into a “slim” shape and selecting suitable parameters for the coil 124, the inner diameter of the magnetically conductive cover 1232 can be reduced, further reducing the mass of the transducer 12 (and consequently the mass of the loudspeaker 10);(3) By inserting a weight-reducing slot into the magnetically conductive cover 1232 or by drilling a hole in the magnet 1233 and / or the magnetically conductive plate (the first magnetically conductive plate 1234 and / or the second magnetically conductive plate 1235), the mass of the transducer 12 can be reduced (and consequently the mass of the loudspeaker 10); (4) By adjusting the overall axial elasticity coefficient of the loudspeaker 10 and the vibration plate 122, the peak frequency of the bone conduction resonance can be kept below 300 Hz, thus preventing the bone conduction loudspeaker from vibrating at low frequencies and causing users to feel significant vibrations; (5) By adjusting the stiffness of the vibrating plate 122 in any direction (radial direction) perpendicular to the direction of vibration, it can resist the magnetic attraction of the magnet assembly 1231, thus preventing magnet misalignment in the transducer 12;(6) By adjusting the ratio of the thickness of the magnetically conductive plate to the thickness of the magnet 1233, the magnetic field strength can be increased while avoiding magnetic saturation, thereby improving the sensitivity of the loudspeaker 10; (7) By adjusting magnetic segment arrangements with different magnetization directions in at least one of the magnet 1233, the magnetically conductive plate and / or the magnetically conductive cover 1232, the magnetic field strength can be improved, further increasing the sensitivity of the loudspeaker 10; (8) By adopting a double-coil configuration (the first coil 1241 and the second coil 1242), double the drive is achieved, and the high-frequency impedance of the coils is reduced, thereby improving the sensitivity of the transducer 12;(9) By attaching double vibration plates (i.e., the vibration plate 122 comprises a first vibration plate 125 and a second vibration plate 126) to both sides of the magnet 1233, a highly sensitive output is ensured, while stable vibration of the magnet 1233 is maintained by the support of the double vibration plates; (10) the coil 124 is attached to the magnetically conductive cover 1232, thereby reducing the magnetic gap between the magnetically conductive cover 1232 and the coil 124, thus concentrating the magnetic field and improving the sensitivity of the transducer 12.

[0085] The basic concepts have been described above, evidently in detail as described above, and do not constitute any limitations of the disclosure. Although there is no explicit explanation here, the person skilled in the art may make various modifications, improvements, and changes to the present disclosure. Such modifications, improvements, and corrections are recommended in the present disclosure, such that the modification, improvement, and change remain in the spirit and scope of the exemplary embodiment of the present disclosure.

[0086] At the same time, specific terms are used in the present disclosure to describe the embodiments of the present disclosure. "An embodiment," "an embodiment," and / or "some embodiments" refer to a specific feature, structure, or property of at least one embodiment of the present disclosure. It is therefore emphasized and should be noted that two or more references to "an embodiment," "an embodiment," or "an alternative embodiment" in different parts of the present disclosure do not necessarily all refer to the same embodiment. Furthermore, certain features, structures, or properties of one or more embodiments of the present disclosure may be combined.

[0087] Unless explicitly stated otherwise in the claims, the order of processing elements and sequences, the use of numbers and letters, or the use of other names in the present disclosure shall not be used to limit the order of the processes and methods of the present disclosure. Although the above disclosure discusses, by means of various examples, what is currently considered to be a multitude of useful embodiments of the disclosure, it is to be understood that such details serve only this purpose and that the appended claims are not limited to the disclosed embodiments but, on the contrary, are intended to cover modifications and equivalent arrangements that are consistent with the spirit and scope of the disclosed embodiments.For example, the implementation of various components described above may be embodied in a hardware device, but it can also be implemented as a purely software solution, e.g., as an installation on an existing server or mobile device.

[0088] It should also be noted that in the preceding description of embodiments of the present disclosure, various features are sometimes combined in a single embodiment, figure, or description thereof in order to simplify the disclosure and facilitate understanding of one or more of the various embodiments. However, this disclosure does not mean that the subject matter of the present disclosure requires more features than those specified in the claims. Rather, the claimed subject matter may consist of fewer than all the features of a single embodiment disclosed above.

[0089] In some embodiments, the numbers expressing quantities of components, properties, etc., and used to describe and claim certain embodiments of the application, are to be understood as being modified in some cases by the terms "approximately," "approximately," or "essentially." Unless otherwise specified, "approximately," "approximately," or "essentially" may mean a deviation of ±20% of the described value. Accordingly, in some embodiments, the numerical parameters used in the description and claims are approximate values, and the approximation may change depending on the properties required for the individual embodiments. In some embodiments, the numerical parameter should take into account the prescribed effective digits and apply a general digit retention method.Although in some embodiments the numerical fields and parameters used to confirm the width of their range are approximate values, in certain embodiments these numerical values ​​are set as accurately as possible within the feasible range.

[0090] With regard to every patent, patent application, patent application disclosure, and other material cited in this disclosure, such as articles, books, manuals, publications, documents, etc., their entire contents are hereby incorporated by reference into this disclosure. Documents from the application history that are inconsistent with or conflict with the content of this disclosure are excluded, as are documents (now or subsequently attached to this disclosure) that limit the broadest scope of the claims in this disclosure.It should be noted that in the event of any discrepancies or conflicts between the descriptions, definitions and / or use of terms in the materials accompanying this disclosure and the terms described in this disclosure, the descriptions, definitions and / or use of terms in this disclosure shall prevail.

[0091] Finally, it should be noted that the embodiments described in this disclosure merely illustrate the principles of the embodiments of this disclosure. Other modifications that may be used are within the scope of this disclosure. As an example, but not as a limitation, alternative configurations of the embodiments of this disclosure may be used in accordance with the teachings contained herein. Accordingly, the embodiments of this disclosure are not limited to those specifically shown and described. QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] CN 202210877819.0

[0001]

Claims

[1] A converter comprising: a magnetic circuit system, wherein the magnetic circuit system comprises a magnet arrangement and a magnetically conductive cover, wherein the magnetically conductive cover at least partially surrounds the magnet arrangement; a vibration plate, wherein the vibration plate comprises a first vibration plate and a second vibration plate, wherein the first vibration plate and the second vibration plate are each arranged on two sides of the magnet arrangement along a vibration direction of the transducer, and each elastically support the magnet arrangement; where the transducer's peak resonance frequency is less than 300 Hz. [2] Converter according to claim 1, wherein the vibration plate is arranged such that the vibration plate connects the magnetically conductive cover and the magnet arrangement. [3] Transducer according to claim 1 or claim 2, wherein an edge region of the first vibration plate is connected to one end of the magnetically conductive cover along the vibration direction of the magnet arrangement, and an edge region of the second vibration plate is connected to the other end of the magnetically conductive cover along the vibration direction of the magnet arrangement. [4] Transducer according to claim 1 or claim 2, wherein the vibration plate and the magnetic circuit system are arranged in the direction of vibration, and one side of the vibration plate is connected perpendicular to the direction of vibration to one end of the magnetically conductive cover perpendicular to the direction of vibration. [5] Transducer according to any one of claims 1 to 4, wherein the total axial elasticity coefficient of the vibration plate is less than 18000 N / m. [6] Transducer according to any one of claims 1 to 5, wherein the axial elasticity coefficient of the first vibration plate or the second vibration plate is less than 9000 N / m. [7] Transducer according to any one of claims 1 to 6, wherein the first vibration plate or the second vibration plate comprises an edge region, a central region and multiple support rods, wherein the multiple support rods connect the edge region and the central region, wherein the central region is connected to the magnet arrangement. [8] Converter according to claim 7, wherein for one of the several support rods, along the longitudinal direction of the first / second vibration plate, the ratio of the distance between a starting point and an end point of the support rod along the longitudinal direction of the first / second vibration plate to the length of the support rod is in a range of 0 - 1.

2. [9] Converter according to claim 7 or claim 8, wherein one of the multiple support rods satisfies one of the following conditions: the length of the support rod is in a range of 7 mm - 25 mm; the thickness of the support rod is in the range of 0.1 mm - 0.2 mm; the width of the support rod is in the range of 0.25 mm - 0.5 mm; or The ratio between the thickness of the vibration plate and the width of the support rod is in the range of 0.16 - 0.

75. [10] Transducer according to any one of claims 1 to 9, wherein the magnet arrangement comprises a magnet, a first magnetically conductive plate, and a second magnetically conductive plate, wherein the first magnetically conductive plate and the second magnetically conductive plate are located on opposite sides of the magnet along the vibration direction of the magnet arrangement; wherein a central area of ​​the first vibrating plate is connected to the first magnetically conductive plate, and a central area of ​​the second vibrating plate is connected to the second magnetically conductive plate. [11] Converter according to any one of claims 1 to 10, remotely comprising a coil arranged in the magnetic circuit system, wherein the magnetically conductive cover is arranged on the outside of the coil, and an outer wall of the coil lies against an inner wall of the magnetically conductive cover. [12] Transducer according to claim 11, wherein the coil comprises a first coil and a second coil, the first coil and the second coil are arranged along the vibration direction of the transducer, and the ratio of the axial height to the radial width of the first coil or the second coil is not less than 3.

5. [13] Converter according to any one of claims 1 to 12, wherein the mass of the converter is in the range of 2 g - 5 g. [14] Transducer according to any one of claims 1 to 13, wherein the magnetically conductive cover has a weight-reducing structure. [15] Converter according to claim 14, wherein the weight-reducing structure comprises a weight-reducing slot or hole; If the magnetically conductive cover is cylindrical, the weight-reducing structure is arranged on the side walls of the cylindrical magnetically conductive cover; If the magnetically conductive cover is shell-shaped, the weight-reducing structure is arranged on the side walls and / or the bottom of the shell-shaped magnetically conductive cover. [16] Loudspeaker comprising a housing, an electronic component and a transducer according to any one of claims 1 to 15, wherein the housing forms a cavity that accommodates the transducer and the electronic component. [17] Loudspeaker according to claim 16, wherein the electronic component includes a vibration-sensitive element that is perpendicular to the direction of vibration of the transducer. [18] Loudspeaker according to claim 17, wherein the vibration-sensitive element comprises an air-conducting loudspeaker, wherein the vibration direction of the transducer is perpendicular to a vibration direction of a diaphragm of the air-conducting loudspeaker. [19] An acoustic playback device, wherein the acoustic playback device comprises a mounting arrangement and a loudspeaker according to any one of claims 16 to 18.

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