Loudspeaker and terminal device

Abstract

This disclosure relates to a loudspeaker and a terminal device. The loudspeaker includes: a voice coil forming a closed space, which generates a first magnetic field when alternating current is applied; a central magnet located within the closed space; and a closed loop surrounding the sidewall of the central magnet, the closed loop inducing a second magnetic field based on the first magnetic field; the direction of the second magnetic field is opposite to the direction of the first magnetic field, in order to reduce the impedance of the voice coil. By providing a closed loop on the central magnet, the closed loop can induce a second magnetic field, the direction of which is opposite to the first magnetic field, ultimately reducing the impedance of the loudspeaker, thereby improving the high-frequency performance of the loudspeaker and enhancing the overall sound effect. Furthermore, it eliminates the need for an additional tweeter unit, saving costs, conserving internal space in the mobile phone, reducing heat generation, and avoiding excessive power consumption.

Description

Technical Field

[0001] This disclosure relates to the field of acoustic devices, and more particularly to a loudspeaker and terminal device. Background Technology

[0002] In related technologies, the audio solutions for terminal devices mainly involve side-emitting sound. This means the speaker diaphragm is angled relative to the sound channel, and the sound emitted by the speaker needs to travel through a relatively long sound channel to be emitted from the side of the terminal device. (See below.) Figure 1 As shown in the figure, the frequency response curve shows that the high-frequency drop of the speaker in the side-emitting terminal device is obvious, resulting in poor sound quality and affecting the overall sound quality of the speaker. Summary of the Invention

[0003] To overcome the problems existing in the related technologies, this disclosure provides a loudspeaker and a terminal device.

[0004] According to a first aspect of the present disclosure, a loudspeaker is provided, comprising: a voice coil forming a closed space, which generates a first magnetic field when an alternating current is applied; a central magnet located within the closed space; and a closed ring surrounding a sidewall of the central magnet, the closed ring inducing a second magnetic field based on the first magnetic field; the direction of the second magnetic field being opposite to the direction of the first magnetic field in order to reduce the impedance of the voice coil.

[0005] In some embodiments, the closing ring is made of a metallic material.

[0006] In some embodiments, the outer wall of the central magnet is provided with a fixing part for fixing the closed loop.

[0007] In some embodiments, the fixing part is a stepped step arranged around the outer wall of the central magnet, and the closing ring is disposed on the stepped step.

[0008] In some embodiments, the closed loop is fitted onto the outer wall of the central magnet by an interference fit.

[0009] In some embodiments, the closed loop is a metal coating formed on the outer wall of the central magnet.

[0010] In some embodiments, the closed loop includes at least one layer of multi-turn coils arranged side-by-side on the outer wall of the central magnet.

[0011] In some embodiments, the closed ring protrudes from the outer wall of the central magnet, and / or the closed ring and the outer wall of the central magnet are in the same plane.

[0012] In some embodiments, the closed loop covers part or all of the sidewalls of the central magnet.

[0013] In some embodiments, the volume of the closed loop is proportional to the strength of the second magnetic field induced by the closed loop.

[0014] According to a second aspect of the present disclosure, a terminal device is provided, including a speaker as described in the first aspect.

[0015] The technical solutions provided by the embodiments of this disclosure can include the following beneficial effects: by setting a closed loop on the central magnet, a second magnetic field can be induced in the closed loop. The direction of the second magnetic field is opposite to that of the first magnetic field, which can ultimately reduce the impedance of the speaker, thereby improving the high-frequency performance of the speaker and enhancing the overall sound effect. In addition, there is no need for an additional tweeter unit, which can save costs, save internal space in the mobile phone, generate less heat, and save more power consumption.

[0016] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and are not intended to limit this disclosure. Attached Figure Description

[0017] The accompanying drawings, which are incorporated in and form a part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure.

[0018] Figure 1 This is a schematic diagram of the frequency response curve of a loudspeaker in related technologies.

[0019] Figure 2 This is a schematic diagram of the structure of a loudspeaker according to an exemplary embodiment.

[0020] Figure 3 This is a schematic diagram of the structure of a loudspeaker according to another exemplary embodiment.

[0021] Figure 4 This is a schematic diagram of the structure of a loudspeaker according to another exemplary embodiment.

[0022] Figure 5 This is a schematic diagram of the structure of a loudspeaker according to another exemplary embodiment.

[0023] Figure 6 This is a schematic diagram of the structure of a loudspeaker according to another exemplary embodiment.

[0024] Figure 7 This is a top view of a loudspeaker according to another exemplary embodiment.

[0025] Figure 8This is a comparison graph of impedance curves shown according to an exemplary embodiment.

[0026] Figure 9 This is a comparison graph of frequency response curves according to an exemplary embodiment. Detailed Implementation

[0027] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with this disclosure. Rather, they are merely examples of apparatuses and methods consistent with some aspects of this disclosure as detailed in the appended claims.

[0028] The side-emitting speakers of the terminal device exhibit a significant high-frequency drop, resulting in poor sound quality and affecting the overall sound performance. To compensate for this high-frequency drop, related technologies improve the high-frequency performance of the terminal device by adding a tweeter. Specifically, the terminal device incorporates both a woofer and a tweeter, with a preset audio threshold value. When the audio frequency exceeds the preset threshold, the tweeter plays the audio; when it falls below the threshold, the woofer plays the audio. This combination of woofer and tweeter achieves a better sound effect.

[0029] The aforementioned solution combining a woofer and a tweeter, while requiring more space, is suitable for foldable phones. However, most current terminal devices are non-foldable. Incorporating two speakers into a non-foldable device increases both the cost and internal stacking space. Furthermore, the addition of a tweeter, when used alongside the woofer, increases the difficulty of tuning and raises technical and manufacturing costs.

[0030] To solve the above-mentioned technical problems, this disclosure provides a loudspeaker. For example... Figure 2 As shown, the loudspeaker includes a magnetic circuit system and a vibration system. The magnetic circuit system includes a center magnet 10, side magnets (not shown in the figure), etc. The vibration system includes a voice coil 20 and a diaphragm 30, etc., with the voice coil 20 and the diaphragm 30 fixedly connected.

[0031] The working principle of the loudspeaker is as follows: A magnetic gap is formed between the central magnet 10 and the side magnets of the magnetic circuit system, and the voice coil 20 of the vibrating system is located in the magnetic gap of the magnetic circuit system. When an alternating electrical signal is transmitted from the external circuit to the voice coil 20 through the lead wire, the voice coil 20, with the alternating electrical signal, forms an alternating magnetic field in the magnetic gap. The voice coil 20, which is alternately magnetized, vibrates under the action of the uniform magnetic field of the magnetic circuit system. The voice coil 20 drives the diaphragm 30 to vibrate up and down in the magnetic gap. The diaphragm 30 does work on the air, causing changes in the air density, forming a sound that can be heard by the human ear, and is emitted from the sound outlet of the loudspeaker.

[0032] Specifically, the voice coil 20 is formed by winding multiple turns of wire. The wire can be self-fusing enameled wire, such as enameled oxygen-free copper wire, copper-clad aluminum wire, pure aluminum wire, etc. The voice coil 20 forms a closed space, and when alternating current is applied, a first magnetic field is generated. The first magnetic field is a changing magnetic field. The magnetic field lines generated by the first magnetic field form a first magnetic flux in the area enclosed by the voice coil 20.

[0033] The center magnet 10 is located within the closed space enclosed by the voice coil 20. A certain distance is maintained between the voice coil 20 and the center magnet 10. A closed ring 40 is arranged around the side wall of the center magnet 10. The side wall of the center magnet 10 refers to the side corresponding to the inner wall of the voice coil 20. Since the center magnet 10 is located within the closed space in the middle of the voice coil 20, and the closed ring 40 is located on the center magnet 10, the closed ring 40 is also located within the closed space enclosed by the voice coil 20. The closed ring 40 does not contact the voice coil 20 and is separated by a certain distance, thereby avoiding affecting the vibration of the voice coil 20.

[0034] Based on the changing first magnetic field, the closed loop 40 induces a second magnetic field; the direction of the second magnetic field is opposite to that of the first magnetic field, thus reducing the impedance of the voice coil 20. In a circuit with resistance and inductance, the opposition to the current in the circuit is called impedance. In this embodiment, the reduction in the speaker's impedance is equivalent to the reduction in the impedance of the voice coil 20. The impedance of the voice coil 20 affects the amplitude of its vibration; blocking a large amplitude reduces the amplitude. When the impedance of the voice coil 20 decreases, it affects the loudness of the sound in that frequency band.

[0035] Specifically, in some embodiments, the closed loop 40 has a closed ring structure and is made of a metallic material. When a changing current flows through the voice coil 20, the closed loop 40, made of metallic material, generates a changing first magnetic field. This changing first magnetic field then produces a changing magnetic flux. According to the principle of electromagnetic induction, when the changing magnetic flux passes through the closed loop 40, an induced electromotive force is generated within the closed loop 40. This induced electromotive force forms an induced current, which in turn generates an induced magnetic field, i.e., a second magnetic field. According to Lenz's law, the second magnetic field generated by the induced current always opposes the change in the first magnetic flux that caused the induced current.

[0036] Therefore, when the voice coil 20 moves up and down, inside the voice coil 20, the first magnetic field passes through the first magnetic flux of the closed loop 40. Since the second magnetic field induced by the closed loop 40 is opposite in direction to the first magnetic field generated by the voice coil 20, it will suppress the change of the first magnetic flux, that is, it is equivalent to the first magnetic flux decreasing. The first magnetic flux is proportional to the induced current of the voice coil 20 itself. When the first magnetic flux decreases, the induced current of the voice coil 20 decreases, and therefore the self-inductance of the voice coil 20 itself decreases.

[0037] Inductance is a property of a closed circuit and is a physical quantity. When current flows through a coil, it creates an induced magnetic field within the coil. This induced magnetic field then generates an induced current that opposes the current flowing through the coil. Inductance includes self-inductance and mutual inductance. As can be seen from the above, a decrease in self-inductance leads to a decrease in overall inductance, that is, a decrease in the equivalent inductance of voice coil 20.

[0038] In a circuit with resistance and inductance, the opposition to the current flowing through the circuit is called impedance. Impedance equals the sum of resistance and inductance. As explained above, a decrease in the inductance of voice coil 20 results in a corresponding decrease in impedance. Since the impedance of voice coil 20 affects the amplitude of its vibration, it influences the loudness of the sound within that frequency range. When the impedance decreases, the amplitude effect of voice coil 20 at high frequencies decreases. Therefore, if the amplitude remains constant or changes only slightly at high frequencies, the sound at high frequencies remains unchanged. Consequently, the sound of the loudspeaker in the high-frequency range will not change.

[0039] like Figure 8 The image shown is a graph illustrating the variation of the impedance curve according to an exemplary embodiment. Figure 8 In the diagram, the horizontal axis represents frequency (in Hz), and the vertical axis represents impedance (in Ω).

[0040] The solid line curve represents the impedance curve without closed loop 40, while the dashed line curve represents the impedance curve with closed loop 40. Figure 8 It can be seen that the impedance curve after setting closed loop 40 coincides with the impedance curve without closed loop 40 in the low-frequency range of 2kHz to 7kHz. However, in the high-frequency range of 7kHz to 20kHz, the impedance drops significantly and remains stable, similar to the impedance in the low-frequency range of 2kHz to 7kHz. In other words, setting closed loop 40 has a greater impact on reducing the impedance generated in the high-frequency range.

[0041] The frequency range of sound that the human ear can hear is 20–20 kHz. Figure 8It can be seen that when the audio frequency is between 2kHz and 7kHz, the impedance remains stable. Therefore, when the speaker emits sound with a frequency between 2kHz and 7kHz, the speaker's own impedance does not affect the sound within this frequency range. However, when the audio frequency is between 7kHz and 20kHz, the impedance increases with increasing frequency (as shown by the solid line). From the above, it can be seen that impedance affects the amplitude of the voice coil 20's vibration. The amplitude is related to the sound loudness; therefore, impedance affects the sound loudness in the 7kHz to 20kHz frequency range, thus affecting the speaker's high-frequency performance in this range.

[0042] In some embodiments, such as Figure 8 As shown, in the high-frequency range of 7kHz to 20kHz, the speaker's impedance decreases by 0% to 20%. With the closed loop 40 installed, the speaker's impedance decreases by 0% to 20% compared to the original impedance without the closed loop 40. The higher the audio frequency, the greater the impedance decrease. This ensures that the impedance remains stable in the high-frequency range of 7kHz to 20kHz, similar to the impedance in the 2kHz to 7kHz range. Since the impedance remains constant, it has no effect on the amplitude of the voice coil 20's vibration, and therefore does not reduce the speaker's sound quality.

[0043] like Figure 9 The diagram shown illustrates the frequency response curve according to an exemplary embodiment. Frequency response is the response of a system to input signals of different frequencies. "Frequency" refers to the frequency of the sound; the higher the frequency, the higher the pitch. "Sound" refers to the loudspeaker's response to the conversion of the frequency in the input electrical signal into sound energy.

[0044] The signal transmitter in the electroacoustic tester outputs a stable signal from 0-20kHz. The receiver then captures the signal emitted by the headphones, presenting it as a logarithmic value in dB SPL. When the response values ​​of many frequencies are connected together, a "frequency response curve" with peaks and valleys is formed. Frequency is the horizontal axis (unit: Hz), and Relative Response is the vertical axis (unit: dB), which can also be called the output level.

[0045] The fluctuations in a frequency response curve indicate the performance capability of headphones or audio equipment (such as speakers) within a specific range, whether it's a high-amplitude or low-amplitude area. An overly prominent curve indicates strong performance in that frequency band, amplifying otherwise weak sounds during music playback; conversely, an overly concave curve indicates weak performance in that frequency band, reducing the sound pressure level of the input signal, weakening otherwise strong sounds, and ultimately leading to distortion. Therefore, the frequency response curve reflects the accuracy with which an audio system or device reproduces the volume levels of various frequency bands in the input signal.

[0046] Depend on Figure 9 It can be seen that when the frequency of the sound emitted by the loudspeaker is between 5KHz and 20KHz, the frequency response curve begins to dip, which indicates that the loudspeaker's sound performance in the 5KHz to 20KHz frequency range is weak, the boost voltage of the input high-frequency signal is reduced, and the loudspeaker is unable to reproduce the loudness of the real sound in the 5KHz to 20KHz frequency range.

[0047] In some embodiments, the output level of the loudspeaker is increased by 0% to 30% in the high frequency band of 5 kHz to 20 kHz.

[0048] With the closed loop 40 set, the output level of the speaker increases by 0-30% compared to the output level without the closed loop 40. This makes the frequency response curve flatter. In other words, the speaker can maintain a stable frequency response curve in the high-frequency range of 5kHz to 20kHz, just like in the 1kHz to 5kHz range. A more stable and flatter frequency response curve indicates enhanced performance in this frequency range. When playing music, this results in increased sound in the high-frequency range, thus improving the speaker's fidelity when playing high-frequency music.

[0049] In some embodiments, the outer wall of the center magnet 10 is provided with a fixing part for fixing the closing ring 40. The closing ring 40 is sleeved on the outer wall of the center magnet 10 and faces the inner wall of the voice coil 20. The closing ring 40 can also be fixed to the outside of the center magnet 10 by interference fit or adhesive.

[0050] The closed loop 40 can be a single metal ring fitted onto the outer wall of the central magnet 10, or multiple closed loops 40 can be stacked and fitted onto the outer wall of the central magnet 10. In this case, each closed loop 40 has a ring-like structure. Multiple closed loops 40 stacked means that the inner diameter of each closed loop 40 gradually increases, with the smallest closed loop 40 fitted onto the outer wall of the central magnet 10, the next largest closed loop 40 fitted onto the outer wall of the smallest closed loop 40, and so on, with multiple closed loops 40 of different inner diameters being stacked sequentially.

[0051] In one embodiment, the closed loop 40 is a metal coating formed on the outer wall of the central magnet 10. The metal coating refers to a covering layer prepared by thermal spraying using metal as the spraying material. The metal coating can be applied to the outer wall of the central magnet 10 by methods such as spraying, electroplating, oxidation (treatment), bluing, phosphate treatment (i.e., chemical treatment), and others.

[0052] Alternatively, the closed loop 40 can also be composed of multi-turn coils wound around the outer wall of the central magnet 10. The multi-turn coils have the same inner diameter and are arranged in parallel. Assuming the multi-turn coils attached to the central magnet 10 are the inner closed loop, another layer of multi-turn coils can be set outside the inner closed loop, namely the outer closed loop, and the inner diameter of the outer closed loop is equal to the outer diameter of the inner closed loop.

[0053] It should be noted that the structure of the closed loop 40 described above is merely exemplary and cannot be used to limit the structure of the closed loop 40 disclosed herein. In some embodiments, the closed loop 40 may be one or a combination of one or more of the embodiments listed above.

[0054] In some embodiments, the closing ring 40 covers part or all of the sidewalls of the central magnet 10. Specifically, assuming the direction of vibration along the voice coil 20 is a first direction A, and the direction perpendicular to the vibration of the voice coil 20 is a second direction B. Partial coverage means that the size of the closing ring 40 in the first direction A can be smaller than the size of the central magnet 10 in the first direction A. In this case, when the closing ring 40 is fitted onto the outer wall of the central magnet 10, the closing ring 40 does not completely cover the outer wall of the central magnet 10.

[0055] In this embodiment, the volume of the closed loop 40 is proportional to the strength of the second magnetic field generated by the closed loop 40. The larger the volume, the greater the opposition of the second magnetic field to the first magnetic flux, the smaller the induced current generated by the voice coil 20, and therefore the lower the impedance of the voice coil 20, resulting in better sound performance of the speaker in the high-frequency range.

[0056] Alternatively, in a fully covered manner, the size of the closed ring 40 in the first direction A can also be equal to the size of the central magnet 10 in the first direction A. In this case, when the closed ring 40 is fitted onto the outer wall of the central magnet 10, the closed ring 40 can completely cover the outer wall of the central magnet 10.

[0057] In some embodiments, the closing ring 40 protrudes from and / or is flush with the outer wall of the central magnet 10. The closing ring 40 may protrude from the outer wall of the central magnet 10, or it may be flush with the outer wall of the central magnet 10, or it may both protrude from and be flush with the outer wall of the central magnet 10. No specific limitation is made here, and the configuration can be made according to design requirements and the internal space requirements of the terminal device.

[0058] The relationship between the closed loop 40 and the outer wall of the central magnet 10 will be described in detail below using several exemplary embodiments.

[0059] As described above, the first direction A can be the direction of vibration of the voice coil 20. This first direction A can include both positive and negative directions: the direction in which the voice coil 20 vibrates outward, pushing the diaphragm 30, is the positive direction of the first direction A, while the direction in which the voice coil 20 vibrates inward, pulling the diaphragm 30, is the negative direction of the first direction A. Similarly, the second direction B can be a direction perpendicular to the first direction A. The second direction B also includes both positive and negative directions: the direction towards the voice coil 20 is the positive direction of the second direction B, and the direction towards the central magnet 10 is the negative direction of the second direction B.

[0060] Example 1

[0061] In some embodiments, such as Figure 2 As shown, the closed loop 40 is fitted onto the outer wall of the central magnet 10 (e.g., Figure 7 As shown, the closed ring 40 can be fixed to the outer wall of the central magnet 10 by interference fit or adhesive. Furthermore, the dimension of the closed ring 40 in the first direction A is smaller than the dimension of the central magnet 10 in the first direction A.

[0062] In some embodiments, such as Figure 3 As shown, the closed ring 40 is sleeved on the outer wall of the central magnet 10. The closed ring 40 can be fixed to the outer wall of the central magnet 10 by interference fit or adhesive. And the dimension of the closed ring 40 in the first direction A is equal to the dimension of the central magnet 10 in the first direction A.

[0063] In this embodiment, the closed loop 40 can be equivalent to multiple turns of metal coils arranged side by side on the outer wall of the central magnet 10. The larger the size of the closed loop 40 in the first direction A, the more turns of the closed loop 40 arranged on the outer wall of the central magnet 10. Each turn of the closed loop 40 induces a second magnetic field under the action of the changing first magnetic field. Since the direction of the second magnetic field induced by the closed loop 40 is opposite to that of the first magnetic field generated by the energized voice coil 20, it will suppress the change of the first magnetic flux.

[0064] When multiple closed loops 40 are arranged side by side on the outer wall of the central magnet 10, the more loops there are, the more the magnetic flux of the second magnetic field generated by each closed loop 40 is superimposed, which strengthens the second magnetic field of the entire closed loop 40. This is equivalent to the greater reduction in the first magnetic flux. The first magnetic flux is proportional to the induced current of the voice coil 20 itself. The greater the reduction in the first magnetic flux, the smaller the induced current of the voice coil 20, and therefore the smaller the self-inductance of the voice coil 20 itself.

[0065] The impedance of the voice coil 20 decreases accordingly. When the impedance decreases, the amplitude of the voice coil 20 at high frequencies decreases. Therefore, the amplitude remains unchanged or changes only slightly at high frequencies, resulting in unchanged sound at high frequencies. Consequently, the rate of change of the loudspeaker's sound in the high-frequency range decreases.

[0066] It should be noted that in practical applications, it can be based on Figure 9 The required range of output level increases is used to set the size of the closed loop 40 in the first direction A. To meet the requirements of high-frequency sound, a suitable size value for the closed loop 40 in the first direction can be selected. This not only reduces the weight of the speaker but also lowers its production cost.

[0067] Example 2

[0068] In some embodiments, such as Figure 4 As shown, the fixing part is a stepped step surrounding the outer wall of the central magnet 10, and the closing ring 40 is disposed on the stepped step. In this embodiment, the closing ring 40 is sleeved on the outer wall of the central magnet 10, and the closing ring 40 can be fixed to the outer wall of the central magnet 10 by interference fit or adhesive.

[0069] Furthermore, the thickness of the closed loop 40 in the second direction B is the same as the dimension of the stepped step in the second direction B. Therefore, the outer wall of the closed loop 40 is flush with the outer wall of the central magnet 10.

[0070] In some embodiments, such as Figure 5 As shown, the fixing part is a stepped step surrounding the outer wall of the central magnet 10, and the closing ring 40 is disposed on the stepped step. In this embodiment, the closing ring 40 is sleeved on the outer wall of the central magnet 10, and the closing ring 40 can be fixed to the outer wall of the central magnet 10 by interference fit or adhesive.

[0071] Furthermore, the thickness of the closed loop 40 in the second direction B is greater than the dimension of the stepped step in the second direction B. Therefore, the outer wall of the closed loop 40 protrudes beyond the outer wall of the central magnet 10.

[0072] In this embodiment, the closed ring 40 is fixed by a stepped platform. As can be seen from the working principle of the loudspeaker, the voice coil 20 moves up and down under the action of the central magnet 10, which drives the diaphragm 30 to vibrate up and down. The vibration of the voice coil 20 will inevitably cause the entire loudspeaker to vibrate.

[0073] As described above, the closed ring 40 can be fixed to the outer wall of the central magnet 10 by interference fit or adhesive. However, under prolonged use, the closed ring 40 may easily detach or fall off the central magnet 10. Therefore, the central magnet 10 is provided with a stepped step, and the lower surface of the closed ring 40 abuts against the stepped surface of the stepped step to prevent the closed ring 40 from detaching from the central magnet 10 in the negative direction of the first direction A, and further to avoid the impact of a detached closed ring 40 on the central magnet 10.

[0074] With the above structure, when the closed loop 40 protrudes beyond the outer wall of the central magnet 10 in the second direction B, it indicates that the thicker the closed loop 40, the smaller the distance between the closed loop 40 and the inner wall of the voice coil 20. A thicker closed loop 40 can be equivalent to multiple ring-shaped closed loops 40 nested together. The outermost closed loop 40 has a larger inner diameter, so when the first magnetic field induced by the voice coil 20 passes through the closed loop 40, the first magnetic flux passing through the closed loop 40 is greater, and the induced current generated on the closed loop 40 is greater. The greater the induced current, the greater the second magnetic field generated. Since the direction of the second magnetic field is opposite to the direction of the first magnetic field, it is equivalent to a greater reduction in the first magnetic flux. The first magnetic flux is proportional to the induced current of the voice coil 20 itself. The greater the reduction in the first magnetic flux, the smaller the induced current of the voice coil 20, and therefore the smaller the self-inductance of the voice coil 20 itself.

[0075] The impedance of the voice coil 20 decreases accordingly. When the impedance decreases, the amplitude of the voice coil 20 at high frequencies decreases. Therefore, the amplitude remains unchanged or changes only slightly at high frequencies, resulting in unchanged sound at high frequencies. Consequently, the rate of change of the loudspeaker's sound in the high-frequency range decreases.

[0076] Example 3

[0077] In some embodiments, such as Figure 6 As shown, the fixing part is a stepped step surrounding the outer wall of the central magnet 10, and the closing ring 40 is disposed on the stepped step. In this embodiment, the closing ring 40 includes a first closing ring 41 and a second closing ring 42. Both the first closing ring 41 and the second closing ring 42 are sleeved on the outer wall of the central magnet 10, and both the first closing ring 41 and the second closing ring 42 can be fixed to the outer wall of the central magnet 10 by interference fit or adhesive.

[0078] In this embodiment, the first closed ring 41 is disposed on the stepped step. The thickness of the first closed ring 41 in the second direction B is equal to the dimension of the stepped step in the second direction B. The second closed ring 42 is fitted onto the outer wall of the central magnet 10 by an interference fit or adhesive, and the outer wall of the second closed ring 42 protrudes beyond the outer wall of the central magnet 10.

[0079] In another embodiment, the first closed ring 41 and the second closed ring 42 of the closed ring 40 are integrally formed. The first closed ring 41 of the closed ring 40 is disposed on the stepped step, and the second closed ring 42 is sleeved on the outer wall of the central magnet 10. From the outside, the first closed ring 41 and the second closed ring 42 have the same dimensions in the positive direction of the second direction B, but the thickness of the first closed ring 41 is greater than the thickness of the second closed ring 42.

[0080] As can be seen from Embodiment 1, the larger the dimension of the closed ring 40 in the first direction A, the smaller the impedance generated by the voice coil 20 (the specific principle is not repeated here, as it is the same as in Embodiment 1). Furthermore, this embodiment increases the thickness at the first closed ring 41. As can be seen from Embodiment 2, this further reduces the impedance of the voice coil 20 (the specific principle is not repeated here, as it is the same as in Embodiment 2). Simultaneously, because the closed ring 40 cooperates with the stepped structure of the central magnet 10, it ensures that the closed ring 40 is not easily dislodged during long-term use of the speaker, thus extending the speaker's lifespan.

[0081] It should be noted that the above embodiments are all exemplary, and those skilled in the art can arbitrarily change the positional relationship between the closed ring 40 and the central magnet 10, as well as the installation method. As long as a closed ring 40 is provided on the outer wall of the central magnet 10, and this can be achieved, it is within the scope of protection of this disclosure.

[0082] As can be seen from the above structure, the advantages of this disclosure are as follows: by setting a closed loop 40 on the central magnet 10, the closed loop 40 can induce a second magnetic field. The direction of the second magnetic field is opposite to that of the first magnetic field, which can ultimately reduce the impedance of the speaker, thereby improving the high-frequency performance of the speaker and enhancing the overall sound effect. In addition, there is no need for an additional tweeter unit, which can save costs, save internal space in the mobile phone, generate less heat, and save more power consumption.

[0083] Based on the same concept, this disclosure also provides a terminal device, including the speaker described above. The terminal device can be a mobile phone, computer, digital broadcasting terminal, messaging device, game console, tablet device, medical device, fitness equipment, personal digital assistant, translator, watch, bracelet, or other wearable device.

[0084] It is understood that the terminal device provided in this disclosure includes hardware structures and / or software modules corresponding to each function in order to achieve the above-mentioned functions. In conjunction with the units and algorithm steps of the various examples disclosed in this disclosure, this disclosure can be implemented in hardware or a combination of hardware and computer software. Whether a function is executed by hardware or by computer software driving hardware depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered beyond the scope of the technical solutions of this disclosure.

[0085] Regarding the apparatus in the above embodiments, the specific manner in which each module performs its operation has been described in detail in the embodiments concerning the loudspeaker, and will not be elaborated upon here.

[0086] It is understood that in this disclosure, "multiple" refers to two or more, and other quantifiers are similar. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, and B alone. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. The singular forms "a," "the," and "the" are also intended to include the plural forms unless the context clearly indicates otherwise.

[0087] It is further understood that the terms "first," "second," etc., are used to describe various types of information, but this information should not be limited to these terms. These terms are only used to distinguish information of the same type from one another, and do not indicate a specific order or degree of importance. In fact, the expressions "first," "second," etc., are completely interchangeable. For example, without departing from the scope of this disclosure, first information can also be referred to as second information, and similarly, second information can also be referred to as first information.

[0088] It is further understood that the terms “center,” “longitudinal,” “lateral,” “front,” “rear,” “up,” “down,” “left,” “right,” “vertical,” “horizontal,” “top,” “bottom,” “inner,” and “outer,” etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this embodiment and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation.

[0089] It can be further understood that, unless otherwise specified, "connection" includes both direct connections where no other components exist between the two parties and indirect connections where other components exist between them.

[0090] It is further understood that although operations are described in a specific order in the accompanying drawings in the embodiments of this disclosure, this should not be construed as requiring these operations to be performed in the specific order or serial order shown, or requiring all of the shown operations to be performed to obtain the desired result. In certain environments, multitasking and parallel processing may be advantageous.

[0091] Other embodiments of this disclosure will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This application is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this disclosure are indicated by the following scope of claims.

[0092] It should be understood that this disclosure is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this disclosure is limited only by the appended claims.

Claims

1. A loudspeaker, characterized in that, include: A voice coil, which forms a closed space around itself, generates a first magnetic field when alternating current is applied to it; A central magnet is located within the closed space. A fixing part is provided on the outer wall of the central magnet. The fixing part is a stepped step arranged around the outer wall of the central magnet. as well as A closed loop is arranged around the side wall of the central magnet. The closed loop includes a first closed loop and a second closed loop. The first closed loop is disposed on the stepped surface, and the second closed loop is sleeved on the outer wall of the central magnet. The first closed loop and the second closed loop are arranged adjacent to each other in the axial direction of the central magnet. The closed loop generates a second magnetic field based on the first magnetic field; the direction of the second magnetic field is opposite to that of the first magnetic field, so as to reduce the impedance of the voice coil. The outer wall of the second closed ring protrudes beyond the outer wall of the central magnet.

2. The loudspeaker according to claim 1, characterized in that, The closed loop is made of a metallic material.

3. The loudspeaker according to claim 1, characterized in that, The closed loop is fitted onto the outer wall of the central magnet via an interference fit.

4. The loudspeaker according to claim 1, characterized in that, The closed loop is a metal coating formed on the outer wall of the central magnet.

5. The loudspeaker according to claim 1, characterized in that, The closed loop includes at least one layer of multi-turn coils arranged side by side on the outer wall of the central magnet.

6. The loudspeaker according to claim 1, characterized in that, The closed loop protrudes from the outer wall of the central magnet, and / or The outer wall of the closed loop is in the same plane as the outer wall of the central magnet.

7. The loudspeaker according to claim 1, characterized in that, The closed loop covers part or all of the sidewalls of the central magnet.

8. The loudspeaker according to claim 1, characterized in that, The volume of the closed loop is proportional to the strength of the second magnetic field induced by the closed loop.

9. A terminal device, characterized in that, Includes the loudspeaker as described in any one of claims 1-8.

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