Open-ear earbud

Abstract

The present application provides an open-ear earbud, comprising a first housing and a sound production assembly. The first housing has an inner side wall and an outer side wall which are oppositely arranged, and the inner side wall faces the external auditory canal in a wearing state. The sound production assembly comprises a loudspeaker; the loudspeaker comprises a first diaphragm and a second diaphragm; the first diaphragm and the second diaphragm are oppositely arranged in a vibration direction and synchronously vibrate in the same direction; the first diaphragm is closer to the inner side wall than the second diaphragm; the first diaphragm and the inner side wall are spaced apart in the vibration direction to form a first acoustic cavity, and the second diaphragm and the outer side wall are spaced apart in the vibration direction to form a second acoustic cavity; first sound outlet holes are formed in the inner side wall, and the first sound outlet holes are acoustically communicated with the loudspeaker by means of the first acoustic cavity; second sound outlet holes are formed in the outer side wall, and the second sound outlet holes are acoustically communicated with the loudspeaker by means of the second acoustic cavity; the first sound outlet holes are a plurality of first small holes arranged in an array; and the second sound outlet holes are a plurality of second small holes arranged in an array. The open-ear earbud further comprises a microphone assembly, so as to achieve active noise reduction on the basis of ambient noise collected by the microphone assembly.

Description

An open-back headphone

[0001] This application claims Chinese application No. CN 202410966001.5, filed on July 17, 2024; Chinese application No. CN 202411452809.8, filed on October 16, 2024; Chinese application No. CN 202411844133.7, filed on December 15, 2024; and Chinese application No. CN 202520976939.5, filed on May 16, 2025, all of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of acoustic technology, specifically to an open-back headphone. Background Technology

[0003] Open-back headphones have become an indispensable tool in people's daily lives and work. As consumers' demands for headphones continue to increase, in addition to having stable output performance, open-back headphones must also be able to reduce environmental noise in noisy or even high-noise environments for normal listening. Therefore, noise cancellation performance has a great impact on the user experience of open-back headphones, so it is necessary to propose an open-back headphone to improve its noise cancellation effect. Summary of the Invention

[0004] This application provides an open-back headphone, which includes a sound-emitting part and an ear hook. The ear hook is configured to place the sound-emitting part near the ear without blocking the external auditory canal when worn. The sound-emitting part includes a first housing and a sound-emitting component, which is disposed inside the first housing. The first housing has an inner sidewall and an outer sidewall that are oppositely disposed. When worn, the inner sidewall faces the external auditory canal, and the outer sidewall is farther away from the external auditory canal than the inner sidewall. The sound-emitting component includes a speaker, which includes a first diaphragm and a second diaphragm. The first diaphragm and the second diaphragm are oppositely disposed in the vibration direction and vibrate synchronously in the same direction. The first diaphragm is closer to the inner sidewall than the second diaphragm. The sidewalls are spaced apart and opposite each other in the vibration direction to form a first acoustic cavity. The second diaphragm and the outer sidewall are spaced apart and opposite each other in the vibration direction to form a second acoustic cavity. A first sound outlet is provided through the inner sidewall, and the first sound outlet is acoustically connected to the speaker through the first acoustic cavity. A second sound outlet is provided through the outer sidewall, and the second sound outlet is acoustically connected to the speaker through the second acoustic cavity. The first sound outlet is a plurality of first small holes arranged in an array, and the second sound outlet is a plurality of second small holes arranged in an array. The open-back headphones also include a microphone assembly. The open-back headphones are configured to adjust the speaker output based on the ambient noise collected by the microphone assembly to achieve active noise reduction of ambient noise.

[0005] In some embodiments, each of the first diaphragm and the second diaphragm includes a main body region and a folded region surrounding the main body region. The folded regions of the first diaphragm and the second diaphragm arch away from each other. The main body region of the first diaphragm and the main body region of the second diaphragm have a first spacing distance along the vibration direction. The inner wall surface of the inner sidewall and the inner wall surface of the outer sidewall have a second spacing distance that is the farthest along the vibration direction. The ratio between the first spacing distance and the second spacing distance is not less than 70%. The loudspeaker also includes a magnetic circuit assembly disposed between the first diaphragm and the second diaphragm.

[0006] In some embodiments, the total opening area of ​​the plurality of second holes is greater than the total opening area of ​​the plurality of first holes.

[0007] In some embodiments, the number of the plurality of second holes is greater than the number of the plurality of first holes.

[0008] In some embodiments, the open-back headphones further include a first acoustic barrier and a second acoustic barrier. The first acoustic barrier is disposed at a first sound outlet and within a first acoustic cavity, and the second acoustic barrier is disposed at a second sound outlet and within a second acoustic cavity. The acoustic impedance of the first acoustic barrier is less than that of the second acoustic barrier.

[0009] In some embodiments, at least a portion of the structure of the first housing extends into the concha cavity, the ear hook includes a adapter connected to the sound-emitting part, and the microphone assembly includes a first microphone assembly disposed within the adapter. The adapter has a first sound-receiving hole on one side near the outer side wall, and the first microphone assembly collects ambient noise through the first sound-receiving hole.

[0010] In some embodiments, at least a portion of the structure of the first housing extends into the concha cavity. The first housing also includes an upper sidewall facing the top of the head in the wearing state and connecting the inner sidewall and the outer sidewall. The microphone assembly includes a second microphone assembly. The upper sidewall is provided with an opening. A portion of the second microphone assembly is received inside the first housing through the opening, and another portion of the second microphone assembly protrudes outside the first housing. The open-back headphones also include a protrusion provided on the upper sidewall. The portion of the second microphone assembly protruding outside the first housing is covered by the protrusion. The protrusion has a second sound-collecting hole on the side near the outer sidewall. The second microphone assembly collects ambient noise through the second sound-collecting hole.

[0011] In some embodiments, the open-back headphones further include a limiting component that seals and fixes the speaker within a first housing and seals and forms a first acoustic cavity and a second acoustic cavity. The limiting component includes a first sealing ring and a second sealing ring. The first sealing ring elastically abuts against an inner wall, and the second sealing ring elastically abuts against an outer wall. The first sealing ring and the second sealing ring seal and fix the speaker from both sides in the vibration direction.

[0012] In some embodiments, the limiting component further includes a first mask and a second mask. The first mask includes a first transverse sidewall and a first longitudinal sidewall. The first transverse sidewall is located between the speaker and the inner sidewall. The second longitudinal sidewall surrounds and is fixedly connected to the speaker around the vibration direction. The second mask includes a second transverse sidewall and a second longitudinal sidewall. The second transverse sidewall is located between the speaker and the outer sidewall. The second longitudinal sidewall surrounds and is fixedly connected to the speaker around the vibration direction. One end of the first sealing ring in the vibration direction is fixed to the first transverse sidewall, and the other end abuts against the inner sidewall. One end of the second sealing ring in the vibration direction is fixed to the second transverse sidewall, and the other end abuts against the outer sidewall.

[0013] In some embodiments, the first longitudinal sidewall and the second longitudinal sidewall are spaced apart along the vibration direction, forming a receiving gap around the speaker between the first mask and the second mask, and the microphone assembly includes a second microphone assembly that is at least partially embedded in the receiving gap, the second microphone assembly being used to collect ambient noise.

[0014] In some embodiments, the open-back headphones further include a first acoustic barrier and a second acoustic barrier. A first rib structure is provided on the first lateral sidewall, and a second rib structure is provided on the second lateral sidewall. The first rib structure is used to support and fix the first acoustic barrier within the first acoustic cavity, and the second rib structure is used to support and fix the second acoustic barrier within the second acoustic cavity. The number of the first rib structure and the number of the second rib structure are both between 3 and 5.

[0015] In some embodiments, each of the first diaphragm and the second diaphragm includes a main region and a loop region surrounding the main region. The loop regions of the first diaphragm and the second diaphragm arch away from each other. Each of the first lateral sidewall and the second lateral sidewall has a central portion and an arcuate portion surrounding the central portion. In the vibration direction, the central portion of the first lateral sidewall faces the main region of the first diaphragm, the arcuate portion of the first lateral sidewall faces the loop region of the first diaphragm, the central portion of the second lateral sidewall faces the main region of the second diaphragm, and the arcuate portion of the second lateral sidewall faces the loop region of the second diaphragm.

[0016] In some embodiments, a first annular platform is provided at the connection between the arcuate portion of the first transverse sidewall and the first longitudinal sidewall, and a second annular platform is provided at the connection between the arcuate portion of the second transverse sidewall and the second longitudinal sidewall. The first and second annular platforms abut against the two sides of the speaker along the vibration direction, and sealant is provided in the abutment area.

[0017] In some embodiments, the limiting component is provided with a first sound guide hole connecting the spaces on both sides of the first lateral sidewall and a second sound guide hole connecting the spaces on both sides of the second lateral sidewall; on a reference plane perpendicular to the vibration direction, the projection of the first sound guide hole and the projection of the first diaphragm have a first overlapping area, the area ratio of the first overlapping area to the projection of the first sound guide hole is not less than 80%, the projection of the first sound outlet hole and the projection of the first sound guide hole have a second overlapping area, the area ratio of the second overlapping area to the projection of the first sound outlet hole is not less than 80%, the projection of the second sound guide hole and the projection of the second diaphragm have a third overlapping area, the area ratio of the third overlapping area to the projection of the second sound guide hole is not less than 80%, and the projection of the second sound outlet hole and the projection of the second sound guide hole have a fourth overlapping area, the area ratio of the fourth overlapping area to the projection of the second sound outlet hole is not less than 80%.

[0018] In some embodiments, the loudspeaker further includes a magnetic circuit assembly and a voice coil assembly. The magnetic circuit assembly is disposed between the first diaphragm and the second diaphragm. The voice coil assembly includes a first voice coil and a second voice coil arranged and connected in the vibration direction of the first diaphragm and the second diaphragm. The first voice coil and the second voice coil are respectively passed through the magnetic gap of the magnetic circuit assembly. The end of the first voice coil away from the second voice coil is connected to the first diaphragm, and the end of the second voice coil away from the first voice coil is connected to the second diaphragm. The magnetic circuit assembly and the voice coil assembly cooperate to drive the first diaphragm and the second diaphragm to vibrate synchronously and in the same direction.

[0019] In some embodiments, the first housing is an integral metal part, the wall thickness of the inner sidewall and the outer sidewall is between 0.2mm and 1mm, the aperture of the plurality of first holes is not less than 0.2mm, the spacing between adjacent first holes is between 0.2mm and 4mm, the aperture of the plurality of second holes is not less than 0.2mm, and the spacing between adjacent second holes is between 0.2mm and 4mm.

[0020] In some embodiments, the ear hook includes an adapter connected to the sound-generating part, the first housing is an integral metal piece, the first housing has a first opening at one end near the adapter, the sound-generating component is inserted into the first housing through the first opening, and the adapter is configured to engage with the first housing through the first opening.

[0021] In some embodiments, the first housing further includes an upper sidewall and an end wall. The upper sidewall is positioned facing the top of the head in the wearing state and connects the inner sidewall and the outer sidewall. The end wall is located at the end of the first housing away from the adapter and connects the inner sidewall, the outer sidewall, and the upper sidewall. The open-back headphones also include a protrusion disposed on the upper sidewall and / or the end wall. The upper sidewall and / or the end wall are provided with a second opening. A portion of the protrusion is embedded in the second opening, and another portion of the protrusion protrudes from the outside of the first housing. The hardness of the protrusion is less than that of the first housing. At least a portion of the structure of the first housing extends into the concha cavity, and the protrusion contacts the concha cavity wall.

[0022] In some embodiments, at least a portion of the structure of the first housing extends into the concha cavity, and the first housing further includes an end wall located at the end of the first housing away from the ear hook and connecting the inner side wall and the outer side wall, with the first sound outlet disposed near the end wall.

[0023] In some embodiments, a sound-tuning hole is provided through the inner sidewall. The sound-tuning hole is positioned at a location farther from the end wall than the first sound outlet hole, and the distance between the sound-tuning hole and the nearest first small hole is not less than 5 times the distance between adjacent first small holes.

[0024] The sound heard by the user is primarily from the first sound outlet. The frequency response curve of the sound output from the first sound outlet has a first resonant peak and a second resonant peak. The peak resonant frequency of the first resonant peak is lower than the peak resonant frequency of the second resonant peak. The greater the distance between the first and second resonant peaks, the wider the flat region of the frequency response curve of the sound output through the first sound outlet, enabling the headphones to perform active noise cancellation over a wider frequency range.

[0025] A first Helmholtz resonator model can be formed by connecting the first acoustic cavity and the first sound outlet. A second Helmholtz resonator model can be formed by connecting the second acoustic cavity and the second sound outlet. The first and second sound outlets serve as the necks of their respective Helmholtz resonator models. The second resonance peak is generated by the first Helmholtz resonator model, and its peak resonant frequency is approximately equal to the resonant frequency of the first Helmholtz resonator model. It should be noted that the vibrations generated by the second Helmholtz resonator model, in addition to being output through the second sound outlet, are also superimposed on the sound output through the first sound outlet due to the synchronous vibrations of the first and second diaphragms. This results in an additional resonance peak in the frequency response curve of the first sound outlet output, besides the first and second resonance peaks, which can be called a third resonance peak. If the third resonance peak is located before the second resonance peak, it will affect the bandwidth of the active noise cancellation.

[0026] The resonant frequency of a Helmholtz resonant cavity model is mainly affected by the cross-sectional area of ​​the neck and the volume of the cavity. A larger neck cross-sectional area results in a higher resonant frequency, while a smaller cavity volume also results in a higher resonant frequency. For the first Helmholtz resonant cavity model, a larger total opening area of ​​the first outlet and a smaller volume of the first acoustic cavity lead to a higher resonant frequency. For the second Helmholtz resonant cavity model, a larger total opening area of ​​the second outlet and a smaller volume of the second acoustic cavity lead to a higher resonant frequency.

[0027] In this application, the speaker includes dual diaphragms spaced apart in the vibration direction. This helps reduce the distance between the first diaphragm and the inner wall, and the distance between the second diaphragm and the outer wall, thereby reducing the volume of the first and second acoustic cavities. Furthermore, by configuring the first sound outlet as an array of multiple small first holes and the second sound outlet as an array of multiple small second holes, both the first and second sound outlets have a large total opening area. This avoids an excessively large single opening area, which would allow foreign objects to easily enter and affect the appearance of the headphones.

[0028] The solution of this application can reduce the volume of the first acoustic cavity and make the first sound outlet have a larger total open area, thereby increasing the resonant frequency of the first Helmholtz resonator model. This causes the second resonant peak to shift to higher frequencies, thus increasing the bandwidth of active noise cancellation. On the other hand, the solution of this application can also reduce the volume of the second acoustic cavity and make the second sound outlet have a larger total open area, thereby increasing the resonant frequency of the second Helmholtz resonator model. This causes the third resonant peak to shift to higher frequencies, reducing the impact of the vibration generated by the second Helmholtz resonator model on the bandwidth of active noise cancellation.

[0029] Furthermore, in the solution of this application, by setting the dual diaphragms to vibrate synchronously in the same direction, it is not only beneficial to counteract the nonlinearity of a single diaphragm, reduce distortion in the low-frequency band, and reduce phase fluctuations, but also beneficial to increase the volume in the low-frequency band, thereby improving the active noise reduction effect in the low-frequency band. Attached Figure Description

[0030] Figure 1 is a schematic diagram of the outline of the front side of the ear as described in this application.

[0031] Figure 2 is a schematic diagram of the wearing state of the headphones when they are worn on the ears according to some embodiments.

[0032] Figure 3 is a schematic diagram of the outer contour structure of the headphones in some embodiments.

[0033] Figure 4 is a schematic diagram of the cross-sectional structure of the sound-generating part in the long axis direction of some embodiments.

[0034] Figure 5 is a schematic diagram of the cross-sectional structure of the sound-generating part in the short axis direction of some embodiments.

[0035] Figure 6 is an exploded view of the structure of the sound-producing part in some embodiments.

[0036] Figure 7 is a schematic diagram of the structure of the headphones in some embodiments.

[0037] Figure 8 is an exploded view of the headphones in some embodiments.

[0038] Figure 9 is an exploded view of a portion of the headphone structure in some embodiments.

[0039] Figures 10A and 10B are schematic diagrams of different numbers of sound outlets in some embodiments.

[0040] Figure 11 is a schematic diagram of frequency response curves corresponding to different shapes and numbers of sound outlet holes in some embodiments.

[0041] Figures 12A to 12F are schematic diagrams of different distributions of sound outlets in some embodiments.

[0042] Figure 13 is a schematic diagram of the frequency response curves corresponding to the sound outlets in Figures 12A to 12F.

[0043] Figure 14 is a schematic diagram of the relative distance between the first sound outlet and the tuning hole in some embodiments.

[0044] Figure 15 is a schematic diagram of the frequency response curves corresponding to different L1-X or L2-X in Figure 14.

[0045] Figure 16 is a schematic diagram of the frequency response curves of the first sound outlet and the tuning hole in Figure 14 at different area ratios.

[0046] Figure 17 is a schematic diagram showing the relative positions of the first sound outlet and the tuning hole in some embodiments.

[0047] Figure 18 is a schematic diagram of the structure of the sound-generating component in the sound-generating part of some embodiments.

[0048] Figure 19 is an exploded view of the structure of the sound-generating component in some embodiments.

[0049] Figure 20 is a schematic cross-sectional view of the sound-generating component in some embodiments.

[0050] Figure 21 is a schematic diagram of the cross-sectional structure of the loudspeaker in some embodiments.

[0051] Figure 22 is a schematic diagram of the structure of a voice coil assembly in some embodiments.

[0052] Figure 23 is a structural exploded view of the voice coil assembly in Figure 22. Detailed Implementation

[0053] The present application will now be described in further detail with reference to the accompanying drawings and specific embodiments. Similar elements in different embodiments are referred to by related similar element reference numerals. In the following embodiments, many details are described to facilitate a better understanding of the present application. However, those skilled in the art will readily recognize that some features may be omitted in different situations, or may be replaced by other elements, materials, or methods. In some cases, certain operations related to the present application are not shown or described in the specification. This is to avoid obscuring the core parts of the present application with excessive description. For those skilled in the art, detailed description of these related operations is not necessary; they can fully understand the related operations based on the description in the specification and general technical knowledge in the art.

[0054] Furthermore, the features, operations, or characteristics described in the specification can be combined in any suitable manner to form various embodiments. At the same time, the steps or actions in the method description can be rearranged or adjusted in a manner obvious to those skilled in the art. Therefore, the various orders in the specification and drawings are only for the clear description of a particular embodiment and do not imply a necessary order, unless otherwise stated that a particular order must be followed.

[0055] The serial numbers assigned to components in this document, such as "first" and "second," are used only to distinguish the described objects and have no sequential or technical meaning. The terms "connection" and "linkage" used in this application, unless otherwise specified, include both direct and indirect connections (linkages).

[0056] Figure 1 is a schematic diagram of the physiological structure of an exemplary ear provided in some embodiments of this application. Referring to Figure 1, the exemplary ear may include physiological parts such as the external auditory canal 11, the concha 12, the cymba concha 13, the triangular fossa 14, the antihelix 15, the scaphoid fossa 16, the helix 17, the earlobe 18, and the crus of the helix 19. Although the external auditory canal 11 has a certain depth and extends to the tympanic membrane of the ear, unless otherwise specified, the external auditory canal 11 can be understood as its entrance away from the tympanic membrane (i.e., the ear hole or ear canal opening). Furthermore, the physiological parts such as the concha 12, the cymba concha 13, and the triangular fossa 14 have a certain volume and depth in three-dimensional space, and the concha 12 is directly connected to the external auditory canal 11, that is, it can be simply regarded as the aforementioned ear hole being located at the bottom of the concha 12.

[0057] Since the external auditory canal 11, concha 12, concha cymba 13, triangular fossa 14 and other physiological parts have a certain depth and volume in three-dimensional space, the headphones provided in some embodiments of this application can achieve stable wearing of the headphones by means of one or more physiological parts of the ear.

[0058] For example, the earphone can be worn by using other parts of the ear besides the external auditory canal 11 (such as the cymba conchae 13, triangular fossa 14, antihelix 15, scaphoid 16, helix 17, etc. or combinations thereof); for example, when worn, the entire or part of the earphone structure can contact the upper part of the external auditory canal 11 (such as one or more physiological parts such as the cymba conchae 13, triangular fossa 14, antihelix 15, scaphoid 16, helix 17, crus of helix 19, etc.); or, when worn, the entire or part of the earphone structure can be located in the first region P1 enclosed by the dotted line in Figure 1, which at least includes the cymba conchae 13 and triangular fossa 14, or in the second region P2 enclosed by the dotted line in Figure 1, which at least includes the conchae cavity 12, or in the front side of the crus of helix 19 (i.e., in the third region P3 enclosed by the dotted line in Figure 1).

[0059] By utilizing parts of the ear other than the external auditory canal 11, the earphone can be worn and sound can be transmitted. This not only "liberates the external auditory canal" and reduces the impact of earphones on the user's ear health, but also effectively improves the user experience. For example, when a user wears earphones on the road, the earphones will not block the external auditory canal 11. This allows the user to receive both the sound from the earphones and ambient sounds (such as horns, car bells, voices of people around, traffic signals, etc.), thereby effectively reducing the occurrence of traffic accidents.

[0060] Due to individual differences among users, ears may vary in shape, size, and other dimensions. To facilitate description and understanding, and to minimize or even eliminate these individual differences, unless otherwise specified, this application primarily uses an ear model with a "standard" shape and size as a reference to describe the structure of the headphones in different embodiments and how they are worn on that ear model. For example, a simulator (such as GRAS 45BC KEMAR) containing a head and its (left and right) ears can be manufactured based on ANSI:S3.36, S3.25, and IEC:60318-7 standards as a reference for wearing headphones, thus representing the scenario of most users normally wearing headphones.

[0061] Therefore, descriptions such as "user wearing," "in wearing state," and "under wearing state" in this application can refer to the headphones described in this application being worn on the ears of the aforementioned simulator. Of course, considering the individual differences among different users, the structure, shape, size, thickness, etc. of one or more parts of the ear can be differentiated according to different ear shapes and sizes. These differentiated designs can be manifested in the characteristic parameters of one or more parts of the headphones having different ranges of values ​​to adapt to different ears.

[0062] It should be noted that in fields such as medicine and anatomy, the human body can be defined by three basic planes: the sagittal plane, the coronal plane, and the horizontal plane, as well as three basic axes: the sagittal axis, the coronal axis, and the vertical axis.

[0063] In this context, the sagittal plane is a section perpendicular to the ground along the anteroposterior direction of the body, dividing the body into left and right parts; the coronal plane is a section perpendicular to the ground along the lateral direction of the body, dividing the body into anterior and posterior parts; and the horizontal plane is a section parallel to the ground along the vertical direction of the body, dividing the body into superior and inferior parts. Correspondingly, the sagittal axis is the axis along the anteroposterior direction of the body and perpendicular to the coronal plane, the coronal axis is the axis along the lateral direction of the body and perpendicular to the sagittal plane, and the vertical axis is the axis along the vertical direction of the body and perpendicular to the horizontal plane.

[0064] Furthermore, the "front side of the ear" mentioned in this application is a concept relative to "back side of the ear." The former refers to the side of the ear that is away from the head, while the latter refers to the side of the ear that faces the head; both refer to the user's ear. Specifically, observing the ear of the simulator along the direction of the human coronal axis yields the schematic diagram of the front side of the ear shown in Figure 1.

[0065] It should be noted that the above description of the ear is for illustrative purposes only and is not intended to limit the scope of this application. Those skilled in the art can make various changes and modifications based on the description in this application (for example, the structure of the earphone can partially or completely cover the external auditory canal 11), and these changes and modifications are still within the protection scope of this application.

[0066] For open-back headphones, when worn, the sound-producing part of the headphones usually cannot form a relatively closed sound transmission channel with the external ear canal 11, which will cause environmental noise to enter the external ear canal 11 and have a significant impact on the user's hearing.

[0067] To reduce or cancel environmental noise in noisy or even high-noise environments, thereby achieving active noise cancellation and improving the sound quality of the headphones, please refer to Figures 2 and 3. Some embodiments of this application provide an open-back headphone (hereinafter referred to as the headphone), including a sound-emitting part 100 and an ear hook. The ear hook is configured to place the sound-emitting part 100 near the ear but without blocking the external auditory canal 11. It should be noted that due to individual differences among users, when the headphones are worn by different users, the sound-emitting part 100 may partially obstruct the external auditory canal 11, but the external auditory canal 11 will still not be blocked. This will be explained in detail below.

[0068] Please refer to Figures 4 to 6. The sound-generating part 100 includes a first housing 110 and a sound-generating component. The sound-generating component is disposed inside the first housing 110 and includes a speaker 120. The speaker 120 can convert electrical signals into corresponding mechanical vibrations, thereby generating sound output (e.g., noise-canceling sound, audio played through headphones, etc.). The sound generated by the speaker 120 may include noise-canceling sound. The noise-canceling sound output to the outside of the first housing 110 can have the same amplitude and opposite phase to the ambient noise near the external auditory canal 11, so as to eliminate the ambient noise near the external auditory canal 11 and achieve active noise cancellation. The sound generated by the speaker 120 may also include other sounds such as call sounds, played audio, and reminder sounds. After these sounds are output to the outside of the first housing 110, they can be guided to the external auditory canal 11 to ensure the user's listening effect.

[0069] In some embodiments, the sound-generating component may further include a limiting component 130, which is used to position and confine the speaker 120 inside the first housing 110. On the one hand, by confining the speaker 120 inside the first housing 110, it can be ensured that the sound generated by the speaker 120 is stably output to the outside of the first housing 110 through the acoustic hole provided in the first housing 110. On the other hand, by confining the speaker 120, it can be prevented from shaking relative to the first housing 110 when vibrating, thereby ensuring the sound output performance of the sound-generating part 100.

[0070] As shown in Figure 6, in some embodiments, the first housing 110 is a metal part, giving the sound-emitting part 100 a metallic appearance. For example, the first housing 110 can be a one-piece molded metal part, with a first opening 1101 at one end near the adapter 300. The sound-emitting component is inserted into the first housing 110 through the first opening 1101, achieving assembly in a relatively simple manner.

[0071] In some embodiments, the open-back headphones also include a microphone assembly, which can be used to collect sound signals, such as user voice and ambient sounds. The open-back headphones are also configured to adjust the output of the speaker 120 based on the ambient noise collected by the microphone, so that the sound output by the speaker 120 includes a sound signal that cancels out the ambient noise, thereby achieving active noise cancellation of the headphones against ambient noise.

[0072] In some embodiments, please refer to Figures 2 and 3. The ear hook may include an ear hook housing and a battery assembly, a circuit board assembly, etc. disposed inside the ear hook housing. The battery assembly, speaker 120, and microphone assembly are electrically connected to the circuit board assembly. The circuit board assembly can be understood as a collection of the headphone's main control board or motherboard and related components. The circuit board assembly plays a role in regulating and managing all or some of the functional components in the headphone; for example, it is used in the headphone to convert and process electrical signals to support the realization of various headphone functions (such as supporting the headphone to turn on and off, switch playback content, increase or decrease volume, etc.).

[0073] For example, referring to Figure 3, the ear hook can be divided into two parts along its length: a battery section 200 and an adapter section 300. The adapter section 300 connects the battery section 200 and the sound-generating section 100. In the wearing state, a part of the battery section 200 (e.g., the part occupied by the battery assembly and the circuit board assembly) hangs between the auricle and the head, and the other part of the battery section 200 extends towards the side of the auricle away from the head and connects to the adapter section 300, so that the sound-generating section 100 is worn near the external auditory canal 11 without blocking the external auditory canal 11, so that the earphone is an open-back earphone. Furthermore, the battery assembly and circuit board assembly can be disposed in the battery section 200, and the adapter section 300 can be provided with earphone buttons and adapter plates for electrically connecting the circuit board assembly to the speaker 120 and the microphone assembly. Referring to Figures 3 and 6 together, the adapter section 300 can be configured to engage with the first housing 110 through a first opening 1101.

[0074] In some embodiments, to improve the stability of the headphones while worn, the headphones may employ any one or a combination of the following methods: First, at least a portion of the ear hook is configured as a conformal structure (e.g., an arc-shaped hook) that conforms to at least one of the back of the ear and the head, thereby increasing the contact area between the ear hook and the ear or head, and thus increasing the resistance to the headphones falling off the ear. Second, at least a portion of the ear hook is configured as an elastic structure, such that the ear hook has a certain elastic deformation while worn, thereby increasing the pressure of the ear hook on the ear or head, and thus increasing the resistance to the headphones falling off the ear. Third, at least a portion of the ear hook is configured to rest against the head while worn, such that the ear hook forms a reaction force pressing against the ear, causing the sound-emitting part 100 to press against the front of the ear, thereby increasing the resistance to the headphones falling off the ear. Fourth, the sound-emitting part 100 and the ear hook are configured to clamp the physiological parts of the ear, such as the area where the helix 17 and the area where the concha 12 are located, respectively, from the front and back sides of the ear when worn, thereby increasing the resistance to the earphone falling off the ear. Fifth, the sound-emitting part 100 is configured to extend at least partially into the physiological parts of the ear, such as the concha 12, cymba concha 13, triangular fossa 14, and scaphoid 16, when worn, thereby increasing the resistance to the earphone falling off the ear.

[0075] In some embodiments, the headphones can be combined with products such as glasses, headphones, head-mounted displays, AR / VR helmets, etc., and the sound-emitting part 100 is worn near the user's ear by means of suspension, clamping, etc.

[0076] Given that most existing open-back headphones with active noise cancellation only support active noise cancellation within a narrow frequency range, in order to enable headphones to have a flatter output across a wider frequency range, thereby effectively enhancing the active noise cancellation effect of headphones in open-back application scenarios, the following mainly introduces the sound-generating part 100.

[0077] Referring to Figures 3 to 6, the sound-emitting part 100 may have a major axis direction and a minor axis direction that are perpendicular to the thickness direction and orthogonal to each other. The major axis direction can be defined as the direction with the maximum extension dimension in the shape of the two-dimensional projection surface of the sound-emitting part 100 (e.g., the projection of the sound-emitting part 100 onto the plane containing its outer sidewall or onto the sagittal plane). (e.g., when the projection shape is rectangular or approximately rectangular, the major axis direction is the length direction of the rectangle or approximately rectangular shape). The minor axis direction can be defined as the direction perpendicular to the major axis direction in the shape of the projection of the sound-emitting part 100 onto the sagittal plane (e.g., when the projection shape is rectangular or approximately rectangular, the minor axis direction is the width direction of the rectangle or approximately rectangular shape). The thickness direction can be defined as the direction perpendicular to the two-dimensional projection surface; for example, the thickness direction coincides with the direction of the coronal axis, both pointing towards the left and right sides of the body. In some embodiments, the thickness direction can also be defined as the direction in which the shell approaches or moves away from the ear when worn. In some embodiments, when the sound-emitting part 100 is tilted while in the wearing state, the major axis direction and the minor axis direction are still parallel or approximately parallel to the sagittal plane. The major axis direction may have a certain angle with the direction of the sagittal axis, that is, the major axis direction is also tilted accordingly. The minor axis direction may have a certain angle with the direction of the vertical axis, that is, the minor axis direction is also tilted. In some embodiments, the entire or part of the structure of the housing of the sound-emitting part 100 can extend into the concha cavity 102. That is, the projection of the housing of the sound-emitting part 100 on the sagittal plane overlaps with the projection of the concha cavity 102 on the sagittal plane. It should be noted that, in the description of this application, when "projection" is mentioned, it refers to orthographic projection.

[0078] Please refer to Figure 6. The first housing 110 of the sound-emitting part 100 includes an inner sidewall 110a and an outer sidewall 110b disposed opposite to each other. The inner sidewall 110a is the housing sidewall of the first housing 110 facing the ear (e.g., external auditory canal 11) in the thickness direction when worn. The outer sidewall 110b is the housing sidewall of the first housing 110 away from the ear (e.g., external auditory canal 11) in the thickness direction when worn.

[0079] The first housing 110 of the sound-emitting part 100 may further include an upper sidewall 110c, a lower sidewall 110d, and an end wall 110e. The upper sidewall 110c is the housing sidewall of the first housing 110 in the short axis direction near the top of the head when worn; the lower sidewall 110d is the housing sidewall of the first housing 110 in the short axis direction away from the top of the head when worn. The end wall 110e is the housing sidewall of the first housing 110 at the end away from the adapter 300. Each of the upper sidewall 110c, lower sidewall 110d, and end wall 110e is connected to the inner sidewall 110a and the outer sidewall 110b. It is understood that these multiple different housing walls can collectively form a receiving cavity of the sound-emitting part 100, and the sound-emitting assembly (e.g., speaker 120, etc.) is housed within this receiving cavity.

[0080] Please refer to Figures 6 to 9. In some embodiments, the open-back headphones further include a protrusion 400 disposed on the upper sidewall 110c and the endwall 110e. The upper sidewall 110c and the endwall 110e are provided with a second opening 1102. A portion of the protrusion 400 is embedded in the second opening 1102, and another portion of the protrusion 400 protrudes from the outside of the first housing 110. The hardness of the protrusion 400 is less than that of the first housing 110. At least a portion of the structure of the first housing 110 extends into the concha cavity, and the protrusion 400 contacts the concha cavity wall. By providing a protrusion 400 with lower hardness to form contact with the concha cavity wall, wearing comfort is improved. For example, the outermost layer of the protrusion 400 can be made of silicone.

[0081] In some embodiments, the protrusion 400 may be provided only on the upper sidewall 110c, or only on the end wall 110e. The reference in this application to the protrusion 400 being provided on "the upper sidewall 110c and / or the end wall 110e" means that the protrusion 400 may be provided on at least one of the upper sidewall 110c and the end wall 110e. Furthermore, the references to "A and / or B" in this application should be understood as at least one of A and B.

[0082] Referring to Figure 5, inside the first housing 110, a first acoustic cavity 111-1 is formed between the speaker 120 and the inner sidewall 110a, and a second acoustic cavity 111-2 is formed between the speaker 120 and the outer sidewall 110b. Correspondingly, the inner sidewall 110a is provided with a first sound outlet 112-1 that is acoustically connected to the speaker 120 through the first acoustic cavity 111-1, and the outer sidewall 110b is provided with a second sound outlet 112-2 that is acoustically connected to the speaker 120 through the second acoustic cavity 111-2.

[0083] The loudspeaker 120 employs a dual-diaphragm loudspeaker, comprising a first diaphragm 121-1 and a second diaphragm 121-2 arranged opposite each other in the vibration direction. The first diaphragm 121-1 and the second diaphragm 121-2 vibrate synchronously in the same direction. "In the same direction" means that the vibration directions of the first diaphragm 121-1 and the second diaphragm 121-2 are consistent, and "synchronous" means that the vibration states of the first diaphragm 121-1 and the second diaphragm 121-2 are consistent in time, that is, the vibration phases of the first diaphragm 121-1 and the second diaphragm 121-2 are consistent. The first diaphragm 121-1 is closer to the inner wall 110a than the second diaphragm 121-2. The first diaphragm 121-1 and the inner wall 110a are spaced apart and opposite each other in the vibration direction (i.e., the thickness direction) to form a first acoustic cavity 111-1, and the second diaphragm 121-2 and the outer wall 110b are spaced apart and opposite each other in the vibration direction to form a second acoustic cavity 111-2.

[0084] Due to various factors such as manufacturing processes, the vibration phases of the first diaphragm 121-1 and the second diaphragm 121-2 are difficult to achieve perfect synchronization under ideal conditions. Therefore, the "synchronous vibration phase" described in this application can mean that, at least within the acoustic frequency range between the first and second resonant peaks (the specific definitions of the first and second resonant peaks are explained in detail later), the phase difference between the first diaphragm 121-1 and the second diaphragm 121-2 at different frequencies is always less than 35°. For example, the test conditions for the phase difference between the first diaphragm 121-1 and the second diaphragm 121-2 can be set based on IEC 60268-7. For instance, in a free field, a 1 / 2-inch standard microphone can be placed near the first sound outlet 112-1, and another 1 / 2-inch standard microphone can be placed near the second sound outlet 112-2. The phase difference between the first diaphragm 121-1 and the second diaphragm 121-2 can be determined based on the sound signals collected by the two standard microphones.

[0085] As shown in Figures 3 to 6, the first sound outlet 112-1 is a plurality of first small holes arranged in an array, and the second sound outlet 112-2 is a plurality of second small holes arranged in an array.

[0086] The sound heard by the user is primarily the sound output from the first sound outlet 111-1. The frequency response curve of the output from the first sound outlet 111-1 has a first resonant peak and a second resonant peak, with the peak resonant frequency of the first resonant peak being lower than that of the second resonant peak. The first resonant peak can be generated by the hardware structure in the sound-emitting part 100, and its peak resonant frequency is mainly affected by the acoustic components in the speaker 120, such as the diaphragm, magnetic circuit assembly, and voice coil assembly. In some embodiments, as the frequency gradually increases, the frequency response curve of the output from the first sound outlet 111-1 may have multiple rising segments, and the first resonant peak can refer to the first of these rising segments. For example, the peak resonant frequency of the first resonant peak can be set to no more than 300Hz.

[0087] A first Helmholtz resonant cavity model can be formed by utilizing the connection between the first acoustic cavity 111-1 and the first sound outlet 112-1. A second Helmholtz resonant cavity model can be formed by utilizing the second acoustic cavity 111-2 and the second sound outlet 112-2. The first sound outlet 112-1 and the second sound outlet 112-2 serve as the neck of their respective Helmholtz resonant cavity models. The second resonance peak can be generated by the first Helmholtz resonant cavity model, and the peak resonant frequency of the second resonance peak is approximately equal to the resonant frequency of the first Helmholtz resonant cavity model.

[0088] A relatively stable flat region with high sound pressure level can be formed between the first and second resonant peaks, and the peak sound pressure level of the second resonant peak is higher than that of the flat region. In some embodiments, the peak sound pressure level of the second resonant peak can be more than 2 dB higher than that of the flat region (test conditions can be set based on IEC 60268-7, for example, in a free field, using a 1 / 2-inch standard microphone, and the microphone being 2 mm away from the headphone output hole). For example, the peak resonant frequency of the second resonant peak can be set to not less than 3.65 kHz, such as not less than 4.5 kHz, not less than 5.8 kHz, not less than 6.7 kHz, not less than 7.5 kHz, not less than 7.75 kHz, not less than 8.75 kHz, not less than 9.25 kHz, not less than 9.5 kHz, etc.

[0089] The greater the distance between the first and second resonant peaks, the wider the flat region of the frequency response curve of the sound output through the first sound outlet 112-1, which enables the headphones to perform active noise cancellation over a wider frequency range.

[0090] It should be noted that the vibration generated by the second Helmholtz resonant cavity model, in addition to being output through the second sound outlet 112-2, will also be superimposed on the sound output from the first sound outlet 112-1 along with the synchronous vibration of the first and second diaphragms. This causes the frequency response curve of the first sound outlet 112-1 to produce an additional resonance peak in addition to the first and second resonance peaks, which can be called the third resonance peak. If the third resonance peak is located before the second resonance peak, it will affect the frequency band width of the active noise reduction.

[0091] The resonant frequency of a Helmholtz resonant cavity model is mainly affected by the cross-sectional area of ​​the neck and the volume of the cavity. A larger neck cross-sectional area results in a higher resonant frequency, while a smaller cavity volume also results in a higher resonant frequency. For the first Helmholtz resonant cavity model, a larger total opening area of ​​the first outlet hole 112-1 and a smaller volume of the first acoustic cavity 111-1 result in a higher resonant frequency. For the second Helmholtz resonant cavity model, a larger total opening area of ​​the second outlet hole 112-2 and a smaller volume of the second acoustic cavity 111-2 result in a higher resonant frequency.

[0092] In this application, by configuring the speaker 120 to include dual diaphragms, with the dual diaphragms spaced apart in the vibration direction, it is beneficial to reduce the distance between the first diaphragm 121-1 and the inner sidewall 110a, and the distance between the second diaphragm 121-2 and the outer sidewall 110b, thereby reducing the volume of the first acoustic cavity 111-1 and the second acoustic cavity 111-2. Furthermore, by configuring the first sound outlet 112-1 as an array of multiple first small holes, and the second sound outlet 112-2 as an array of multiple second small holes, the first sound outlet 112-1 and the second sound outlet 112-2 each have a large total opening area, while avoiding an excessively large single opening area. An excessively large single opening area makes it easier for foreign objects to enter and also affects the appearance of the headphones.

[0093] The solution of this application can reduce the volume of the first acoustic cavity 111-1 and make the first sound outlet 112-1 have a larger total opening area, thereby increasing the resonant frequency of the first Helmholtz resonator model. This causes the second resonant peak to shift to higher frequencies, thus increasing the bandwidth of active noise reduction. On the other hand, the solution of this application can also reduce the volume of the second acoustic cavity 111-2 and make the second sound outlet 112-2 have a larger total opening area, thereby increasing the resonant frequency of the second Helmholtz resonator model. This causes the third resonant peak to shift to higher frequencies, reducing the impact of the vibration generated by the second Helmholtz resonator model on the bandwidth of active noise reduction.

[0094] Furthermore, in the solution of this application, by setting the dual diaphragms to vibrate synchronously in the same direction, it is not only beneficial to counteract the nonlinearity of a single diaphragm, reduce distortion in the low-frequency band, and reduce phase fluctuations, but also beneficial to increase the volume in the low-frequency band, thereby improving the active noise reduction effect in the low-frequency band.

[0095] For example, in some embodiments, the peak resonant frequency of the second resonant peak can be set to be no less than 3 compared to the peak resonant frequency of the first resonant peak, thereby effectively increasing the width of the flat region of the frequency response curve of the sound output through the first sound outlet 112-1, providing support for active noise cancellation of the headphones over a wider frequency range. In some embodiments, the ratio of the peak resonant frequency of the second resonant peak to the peak resonant frequency of the first resonant peak can be set to be no less than 13, and in some embodiments, the ratio of the peak resonant frequency of the second resonant peak to the peak resonant frequency of the first resonant peak can be set to be no less than 20.

[0096] In some embodiments, when worn, at least a portion of the first housing 110 may be located within the concha 12, and the inner wall 110a cooperates with the concha 12 to form an auxiliary cavity communicating with the external auditory canal 11. This auxiliary cavity is typically in a semi-open state, and the first sound outlet 112-1 is located within the auxiliary cavity. Thus, the sound output through the first sound outlet 112-1 can be focused by the constraint of the auxiliary cavity, with most of the sound propagating into the external auditory canal 11. The small portion of sound propagating outside the external auditory canal 11 (e.g., noise-canceling sounds) can be counteracted by the ambient noise near the external auditory canal 11, thereby improving listening performance, enhancing active noise cancellation, and reducing sound leakage.

[0097] As shown in Figure 5, in some embodiments, each of the first diaphragm 121-1 and the second diaphragm 121-2 includes a main body region 121a and a folded ring region 121b surrounding the main body region 121a. The folded ring regions 121b of the first diaphragm 121-1 and the second diaphragm 121-2 arch away from each other. This arrangement helps to further reduce the volume of the first acoustic cavity 111-1 and the second acoustic cavity 111-2, increase the resonant frequency of the first Helmholtz resonator model, thereby shifting the second resonant peak to higher frequencies, thus increasing the bandwidth of active noise cancellation, and increasing the resonant frequency of the second Helmholtz resonator model, causing the third resonant peak to shift to higher frequencies, reducing the impact of the vibration generated by the second Helmholtz resonator model on the bandwidth of active noise cancellation.

[0098] The loudspeaker 120 may also include a magnetic circuit assembly and a voice coil assembly disposed between the first diaphragm 121-1 and the second diaphragm 121-2. The main body region 121a can move in the vibration direction under the driving force generated by the cooperation of the magnetic circuit assembly and the voice coil assembly in the loudspeaker 120, thereby generating sound by pushing or squeezing the air inside the first housing 110 or the air inside the loudspeaker 120. The surround region 121b can undergo elastic deformation as the main body region 121a moves, providing elastic restoring force for the main body region 121a.

[0099] Since the first diaphragm 121-1 and the second diaphragm 121-2 are spaced apart in the vibration direction, the magnetic circuit assembly can be disposed between the first diaphragm 121-1 and the second diaphragm 121-2. The first diaphragm 121-1 and the second diaphragm 121-2 can share the magnetic circuit assembly, thereby reducing the number of components and lowering the hardware cost.

[0100] In some embodiments, the main body region 121a of the first diaphragm 121-1 and the main body region 121a of the second diaphragm 121-2 have a first spacing distance L1 along the vibration direction, and the inner wall surface of the inner sidewall 110a and the inner wall surface of the outer sidewall 110b have a second spacing distance L2 that is the farthest along the vibration direction, and the ratio between the first spacing distance L1 and the second spacing distance L2 is not less than 70%. For example, the ratio between the first spacing distance L1 and the second spacing distance L2 can be 70%, 75%, 80%, 85%, 90%, etc.

[0101] This configuration minimizes the distance between the first diaphragm 121-1 and the inner wall 110a, as well as the distance between the second diaphragm 121-2 and the outer wall 110b. This helps reduce the volume of the first acoustic cavity 111-1 and the second acoustic cavity 111-2, increases the resonant frequency of the first Helmholtz resonator model, and thus shifts the second resonant peak to higher frequencies, thereby increasing the bandwidth of active noise reduction. It also increases the resonant frequency of the second Helmholtz resonator model, causing the third resonant peak to shift to higher frequencies, reducing the impact of vibrations generated by the second Helmholtz resonator model on the bandwidth of active noise reduction.

[0102] The following section will discuss in detail the impact of the specific arrangement of the sound outlet on the high-frequency resonance peak of the headphone's frequency response curve. It should be noted that the high-frequency resonance peak, high-frequency peak, etc., mentioned below are, in some embodiments, the second resonance peak of the sound output through the first sound outlet 112-1.

[0103] Please refer to Figures 10A, 10B, and 11; wherein, Figures 10A and 10B are schematic diagrams showing different numbers of sound outlet holes according to some embodiments of this application; wherein, the total opening area of ​​the sound outlet holes shown in Figures 10A and 10B is the same, that is, the opening ratio is the same, wherein the formula for calculating the opening ratio is the ratio of the total opening area of ​​the sound outlet holes to the area of ​​the corresponding shell sidewall of the first shell 110, for example, the opening ratio of the first sound outlet hole 112-1 is the ratio of the area of ​​the first sound outlet hole 112-1 to the area of ​​the inner sidewall 110a.

[0104] Figure 11 is a schematic diagram of the frequency response curves of loudspeakers corresponding to different numbers of sound outlets according to some embodiments of this application. In Figure 11, curve L521 represents the frequency response of the sound-emitting part 100 corresponding to a single sound outlet with an aperture ratio of 0.25; curve L522 represents the frequency response of the sound-emitting part 100 corresponding to an array of sound outlets, a large mesh opening, and an aperture ratio of 0.2178 as shown in Figure 10A; and curve L523 represents the frequency response of the sound-emitting part 100 corresponding to an array of sound outlets, a small mesh opening, and an aperture ratio of 0.2178 as shown in Figure 10B.

[0105] Please refer to Figure 11 and compare curves L521, L522, and L523. As the size of a single sound outlet decreases and the number of sound outlets increases, the corresponding high-frequency resonance peak of the curve shifts to higher frequencies. Therefore, by setting the first sound outlet 112-1 to include multiple first small holes arranged in an array, and the second sound outlet 112-2 to include multiple second small holes arranged in an array, the high-frequency peak of the speaker 120 can be shifted to higher frequencies, ensuring active noise reduction while preventing foreign objects from entering, thus meeting the appearance design requirements of the sound-emitting part 100 or headphones.

[0106] Please refer to Figure 11 and compare curves L521, L522, and L523. As the size of a single sound outlet decreases and the number of sound outlets increases, the corresponding curves show a decrease in the output sound pressure level at high frequencies. With a constant aperture ratio, if the size of a single sound outlet is too small, although the total number of sound outlets can be increased, leading to an increase in the high-frequency resonance peak, it will also increase the acoustic impedance of the sound outlet, thus affecting the output sound pressure level. Therefore, to ensure the output sound pressure level of the first sound outlet 112-1, the diameter of a single first small hole can be no less than 0.2 mm. The "first small hole" and "second small hole" mentioned in this application can be regular circular holes, elliptical holes, polygonal holes, etc. The "diameter" mentioned in this application refers to the maximum distance between any two points on the edge of the small hole.

[0107] Please refer to Figures 12A to 12F, which are schematic diagrams of sound outlet holes with different distributions of array openings according to some embodiments of this application. Figure 12A shows that the sound outlet holes are distributed on one side of the shell sidewall corresponding to the first shell 110 along the long axis, with a corresponding opening ratio of 0.15; Figure 12B shows that the sound outlet holes are distributed in a ring on one side of the shell sidewall corresponding to the first shell 110 along the long axis, with a corresponding opening ratio of 0.15; Figure 12C shows that the sound outlet holes are distributed in a ring on the entire surface of the shell sidewall corresponding to the first shell 110, with a corresponding opening ratio of 0.15; Figure 12D shows that the sound outlet holes are distributed in a ring on one side of the shell sidewall corresponding to the first shell 110 along the long axis, and the corresponding shell sidewall is provided with a pressure relief hole on the other side along the long axis, with an opening ratio of 0.15 for the sound outlet holes and an opening ratio of 0.0375 for the pressure relief holes; Figure 12E shows that the sound outlet holes are distributed in the central area of ​​the shell sidewall corresponding to the first shell 110, with a corresponding opening ratio of 0.15; Figure 12F shows that the sound outlet holes are distributed on the entire surface of the shell sidewall corresponding to the first shell 110, with a corresponding opening ratio of 0.30.

[0108] Please refer to Figure 13, which is a schematic diagram of the frequency response curves of the sound-emitting part 100 corresponding to different distributions of sound outlets according to some embodiments of this description. Curve L541 corresponds to the sound outlet shown in Figure 12C; curve L542 corresponds to the sound outlet shown in Figure 12B; curve L543 corresponds to the fully open sidewall of the first housing 110 with an opening ratio of 1; curve L544 corresponds to the sound outlet shown in Figure 12D; curve L545 corresponds to the sound outlet shown in Figure 12E; curve L546 corresponds to the sound outlet shown in Figure 12F; and curve L547 corresponds to the speaker 120 without the first housing 110.

[0109] Please refer to Figure 13. Comparing curves L546 and L543, the positions of the high-frequency peaks are basically the same, both around 8.3kHz. Comparing curves L541, L542, L544, L545, and L543, the frequencies corresponding to the high-frequency peaks of curves L541, L542, L544, and L545 (with an aperture ratio of 0.15) are all lower than the frequencies corresponding to the high-frequency peaks of curve L513 (with an aperture ratio of 0.3). Comparing curves L541, L542, L544, and L545 (all with an aperture ratio of 0.15), the high-frequency peak of curve L544 is located near 8.3kHz, and has an additional resonance peak near 6.5kHz; the high-frequency peak of curve L541 is located near 8.3kHz, and has an additional resonance peak near 6.1kHz; the high-frequency peak of curve L545 is located near 7.1kHz; and the high-frequency peak of curve L542 is located near 6.5kHz. Among them, when the opening ratio of the sound outlet is 0.15, the high frequency peaks corresponding to curves L541, L542, L544 and L545 are all higher than 6kHz.

[0110] Based on this, in some embodiments, when the sound outlet consists of multiple small holes arranged in an array, the aperture ratio of the sound outlet can be no less than 0.1 in order to ensure that the headphones have a relatively flat output over a wider frequency range. Therefore, the ratio of the total opening area of ​​the first sound outlet 112-1 to the area of ​​the inner sidewall 110a can be no less than 10%, and the ratio of the total opening area of ​​the second sound outlet 112-2 to the area of ​​the outer sidewall 110b can be no less than 10%.

[0111] For example, when the aperture ratio of the sound outlet is 0.15, the high-frequency peaks corresponding to curves L541, L542, L544, and L545 are all higher than 6kHz. In this case, the headphones have a relatively flat output over a wider frequency range, resulting in better active noise cancellation. Alternatively, the aperture ratio of the sound outlet can be no less than 0.3, which further allows the headphones to have a relatively flat output over an even wider frequency range, resulting in a high-frequency peak in the output frequency response higher than 8kHz.

[0112] The first sound outlet 112-1 includes multiple first small holes arranged in an array. In order to shift the second resonant peak to the higher frequencies as much as possible, increase the bandwidth of active noise reduction, and ensure the sound pressure level output by the first sound outlet 112-1 to guarantee the user's listening effect, the aperture of a single first small hole can be set to not less than 0.2mm. For example, the aperture of a single first small hole can be set to 0.2mm, 0.5mm, 0.8mm, 1mm, 1.5mm, 2mm, or even larger. The spacing between two adjacent first small holes can be between 0.2mm and 4mm. For example, the spacing between two adjacent first small holes can be 0.2mm, 0.5mm, 0.8mm, 1mm, 1.5mm, 2mm, or 4mm. The second sound outlet 112-2 includes multiple second small holes arranged in an array. In order to reduce the impact of the vibration generated by the second Helmholtz resonator model on the frequency band of active noise reduction, the aperture of a single second small hole can be set to not less than 0.2mm. For example, the aperture of a single second small hole can be set to 0.2mm, 0.5mm, 0.8mm, 1mm, 1.5mm, 2mm, or even larger. The distance between two adjacent second small holes can be between 0.2mm and 4mm. For example, the interval between two adjacent second small holes can be 0.2mm, 0.5mm, 0.8mm, 1mm, 1.5mm, 2mm, or 4mm.

[0113] It should be noted that "between AB" as mentioned in this application includes the endpoints A and B; "the distance between the two first holes" as mentioned in this application refers to the minimum distance between the outline edges of the two first holes; and "the distance between the two second holes" as mentioned in this application refers to the minimum distance between the outline edges of the two second holes.

[0114] As mentioned above, in some embodiments, the first housing 110 is a one-piece metal part. By making the first housing 110 a metal part, the inner sidewall 110a and the outer sidewall 110b have relatively large strength, enabling the formation of multiple arrayed first small holes and multiple arrayed second small holes. This ensures that the first sound outlet 112-1 has a relatively large total opening area, and the second sound outlet 112-2 has a relatively large total opening area. In some embodiments, to ensure that the inner sidewall 110a and the outer sidewall 110b have sufficient strength, the wall thickness of the inner sidewall 110a and the outer sidewall 110b can be set to be between 0.2mm and 1mm. For example, the wall thickness of the inner sidewall 110a can be 0.2mm, 0.4mm, 0.5mm, 0.6mm, 0.8mm, or 1mm, and the wall thickness of the outer sidewall 110b can be 0.2mm, 0.4mm, 0.5mm, 0.6mm, 0.8mm, or 1mm.

[0115] In some embodiments, the total opening area of ​​the plurality of second holes is greater than the total opening area of ​​the plurality of first holes. That is, the total opening area of ​​the second sound outlet hole 112-2 can be greater than the total opening area of ​​the first sound outlet hole 112-1.

[0116] For example, when the resonant frequency of the second Helmholtz resonant cavity model is H1, the frequency response curve of the sound output from the second sound outlet 112-2 has a resonant peak near frequency H1. The vibrations generated by the second Helmholtz resonant cavity model, besides being output through the second sound outlet 112-2, are superimposed on the sound output from the first sound outlet 112-1 due to the synchronous vibrations of the first and second diaphragms. This results in a resonant peak in the frequency response curve of the first sound outlet 112-1 near frequency H2, which is typically lower than frequency H1. When frequency H2 is greater than the peak resonant frequency of the second resonant peak (approximately equal to the resonant frequency of the first Helmholtz resonant cavity model), the impact of the vibrations generated by the second Helmholtz resonant cavity model on the bandwidth of active noise cancellation can be minimized.

[0117] Therefore, by setting the total opening area of ​​the second sound outlet 112-2 to be greater than the total opening area of ​​the first sound outlet 112-1, the resonant frequency of the second Helmholtz resonant cavity model can be made greater than the resonant frequency of the first Helmholtz resonant cavity model, causing the third resonance peak to shift to higher frequencies. This helps to minimize the impact of the vibration generated by the second Helmholtz resonant cavity model on the frequency band of active noise reduction.

[0118] In some embodiments, the number of the plurality of second holes is greater than the number of the plurality of first holes.

[0119] Within the speaker 120, a first sound outlet 112-1 located on the inner sidewall 110a can output sound, and a second sound outlet 112-2 located on the outer sidewall 110b can also output sound. The speaker 120 as a whole can be equivalent to a dipole sound source. By providing a larger number of second holes in the second sound outlet 112-2, the sound pressure level output by the second sound outlet 112-2 can be reduced, thus reducing the impact of the sound output by the second sound outlet 112-2 on active noise cancellation. In addition, it can also shift the acoustic zero point of the dipole sound source towards the side where the outer sidewall 110b is located.

[0120] Referring to Figure 5, in some embodiments, the sound-generating component further includes a first acoustic barrier 160-1 and a second acoustic barrier 160-2. The first acoustic barrier 160-1 is disposed at the first sound outlet 112-1 and within the first acoustic cavity 111-1. The second acoustic barrier 160-2 is disposed at the second sound outlet 112-2 and within the second acoustic cavity 111-2. The acoustic impedance of the first acoustic barrier 160-1 is less than that of the second acoustic barrier 160-2. The first acoustic barrier 160-1 can cover the first sound outlet 112-1, and the second acoustic barrier 160-2 can cover the second sound outlet 112-2, thus providing dustproof and waterproof functions.

[0121] By setting the acoustic impedance of the first acoustic barrier 160-1 to be less than that of the second acoustic barrier 160-2, the sound pressure level output from the second sound outlet 112-2 can be reduced, thus reducing the impact of the sound output from the second sound outlet 112-2 on active noise cancellation. Furthermore, it can shift the acoustic null point of the dipole sound source towards the side where the outer wall 110b is located. In some embodiments, the ratio of the acoustic impedance of the second acoustic barrier 160-2 to that of the first acoustic barrier 160-1 is not less than 10; for example, this ratio can be 10, 30, 50, 60, 70, 80, 100, or even greater. For instance, the acoustic impedance of the first acoustic barrier 160-1 is less than 10 Rayles, and the acoustic impedance of the second acoustic barrier 160-2 is greater than 700 Rayles. As mentioned earlier, the open-back headphones also include a microphone assembly, which can be used to collect ambient noise. The open-back headphones can adjust the output of the speaker 120 based on the ambient noise collected by the microphone assembly to perform active noise cancellation. The sound-emitting part 100 and / or the adapter part 300 may be provided with a sound-receiving hole that is acoustically connected to the microphone assembly. In order to prevent the sound emitted by the speaker 120 from being picked up by the sound-receiving hole, the sound-receiving hole can be set near the acoustic null point of the dipole sound source.

[0122] In addition, when the microphone is positioned close to the inner wall 110a in the thickness direction, it may be blocked by ears, which is not conducive to collecting ambient noise. When the microphone is positioned close to the outer wall 110b in the thickness direction, the position is more open and can reduce the obstruction by ears.

[0123] By shifting the acoustic null point of the dipole sound source towards the side where the outer wall 110b is located, the microphone hole can be positioned close to the outer wall 110b and near the acoustic null point of the dipole sound source. This not only reduces the obstruction of the microphone hole by the ear but also prevents the sound emitted by the speaker 120 from being picked up by the microphone hole, thus enabling the microphone hole to collect high-quality ambient noise.

[0124] Please refer to Figures 7 and 8 together. In some embodiments, the microphone assembly includes a first microphone assembly 170, which is disposed within the adapter 300. The adapter 300 has a first sound-collecting hole 171 on the side near the outer wall 110b along the vibration direction. The first microphone assembly 170 collects ambient noise through the first sound-collecting hole 171. The open-back headphones can adjust the output of the speaker 120 based on the ambient noise collected by the first microphone assembly 170 to perform active noise cancellation. On the one hand, the first sound-collecting hole 171 is disposed on the adapter 300, which is relatively far from the ear, and is disposed near the outer wall 110b, which can reduce ear obstruction. On the other hand, the first sound-collecting hole 171 is disposed on the side near the outer wall 110b, which is near the acoustic null point of the dipole sound source, which can prevent the sound emitted by the speaker 120 from being collected by the first sound-collecting hole 171, so that the first sound-collecting hole 171 collects high-quality ambient noise.

[0125] Please refer to Figures 7, 8, and 9 together. In some embodiments, the microphone assembly includes a second microphone assembly 180. A portion of the second microphone assembly 180 is housed inside the first housing 110 via a second opening 1102 on the upper sidewall 110c, while another portion protrudes from the outside of the first housing 110 to reduce the space occupied inside the first housing 110, thus allowing the overall size of the first housing 110 to be relatively small. The portion of the second microphone assembly 180 protruding from the outside of the first housing 110 can be covered by a protrusion 400. The protrusion 400 has a second sound-collecting hole 181 on the side near the outer sidewall 110b. The second microphone assembly 180 collects ambient noise through the second sound-collecting hole 181. The open-back headphones can adjust the output of the speaker 120 based on the ambient noise collected by the first microphone assembly 170 to perform active noise cancellation. The second sound hole 181 is located on the side of the protrusion 400 near the outer wall 110b, near the acoustic null point of the dipole sound source. This reduces the obstruction of the second sound hole 181 by the ear and also prevents the sound emitted by the speaker 120 from being collected by the second sound hole 181, thereby enabling the second sound hole 181 to collect high-quality environmental noise.

[0126] The second microphone assembly 180 is disposed on the upper sidewall 110c of the first housing 110, and is closer to the external ear canal than the first microphone assembly 170, thus being more obstructed by the ear. In some embodiments, when the open-back headphones detect significant wind noise, the second microphone assembly 180 can be activated to collect ambient noise, while the first microphone assembly 170 can be disabled to reduce the impact of wind noise. When the open-back headphones detect relatively low wind noise, the first microphone assembly 170 can be activated to collect ambient noise.

[0127] As shown in Figures 6 and 14, in some embodiments, the sound-emitting part 100 extends at least partially into the concha cavity 12 at the end opposite to the ear hook, and the first housing 110 is provided with an end wall 110e at the end opposite to the ear hook. The first sound outlet 112-1 can be located close to the end wall 110e. In this way, the first sound outlet 112-1 can be closer to the external auditory canal, improving the user's listening effect and reducing sound leakage.

[0128] When worn, the first sound outlet 112-1 is located on the side closer to the external auditory canal 11. Due to limitations such as the opening size of the first sound outlet 112-1 and the coverage area relative to the first acoustic cavity 111-1, some of the sound generated by the speaker 120 (specifically, the first diaphragm 121-1) in the first acoustic cavity 111-1 will be obstructed by the shell sidewall of the first housing 110 (e.g., the part of the inner sidewall 110a where the first sound outlet 112-1 is not opened) and cannot be directly output through the first sound outlet 112-1. As a result, a standing wave will be formed in the first acoustic cavity 111-1. This will cause the peak resonant frequency of the second resonant peak to shift forward (i.e., shift to lower frequencies), affecting the effect of active noise cancellation of the headphones in a wider frequency range.

[0129] Therefore, in some embodiments, please refer to Figures 6, 12D, 14 and 17, the inner sidewall 110a is also provided with a through-hole 113-3, which is connected to the first acoustic cavity 111-1. Based on the connection between the first sound outlet 112-1 and the through-hole 113-3 and the first acoustic cavity 111-1, the peak resonant frequency of the second resonant peak of the sound output to the outside of the first housing 110 through the first sound outlet 112-1 can be adjusted by means of the through-hole 113-3, for example, so that the peak resonant frequency of the second resonant peak is not less than 1kHz.

[0130] Specifically, most of the sound generated by the speaker 120 within the first acoustic cavity 111-1 is output through the first sound outlet 112-1, while a small portion of the sound is output through the tuning port 113-3. This minimizes the formation of standing waves within the first acoustic cavity 111-1, allowing the peak resonant frequency of the second resonant peak of the frequency response curve of the sound output from the first sound outlet 112-1 to shift as high as possible. This adjustment of the peak resonant frequency ultimately results in a flatter output across a wider frequency range, facilitating active noise cancellation over a broader frequency spectrum. In some embodiments, the first acoustic barrier 160-1 can cover the first sound outlet 112-1 and the tuning port 113-3, providing dust and water protection.

[0131] Considering the different relative positions between the tuning port 113-3 and the first sound outlet 112-1, it may affect the output of the loudspeaker 120 or the position of the peak resonant frequency of the resonant peak. Referring to Figure 14, taking an example where both the first sound outlet 112-1 and the tuning port 113-3 adopt a multi-hole structure, L1-X is defined as the minimum distance between the first sound outlet 112-1 and the tuning port 113-3, and L2-X is defined as the minimum distance from the boundary of the first acoustic cavity 111-1 to either the first sound outlet 112-1 or the tuning port 113-3. It should be noted that the minimum distance here refers to the distance between the outline edges of any two holes, or the distance from the outline edge of any hole to the boundary of the acoustic cavity.

[0132] Please refer to Figure 15, which is a schematic diagram of the frequency response curves of the sound-emitting section 100 corresponding to different L1-X and L2-X according to some embodiments of this description. In Figure 15, LM represents either L1-X or L2-X.

[0133] As shown in Figure 15, the high-frequency peak corresponding to LM = 1.3mm is 9.5kHz, LM = 2.1mm is 9.25kHz, LM = 2.7mm is 9kHz, LM = 3.4mm is 8.75kHz, LM = 4mm is 7.75kHz, LM = 6mm is 7.5kHz, LM = 8mm is 6.7kHz, LM = 10mm is 5.8kHz, LM = 12mm is 4.5kHz, and LM = 14mm is 3.65kHz. With the increase of LM, the corresponding high-frequency peaks shift forward, which means that the total opening area decreases accordingly, resulting in a decrease in the sound pressure level output from the inner wall 110a side. When LM = 14mm, compared to other smaller LMs, the sound pressure level at 1kHz decreases by 3dB, which is acceptable.

[0134] Therefore, in some embodiments, when both the first sound outlet 112-1 and the tuning hole 113-3 adopt a porous structure, the minimum distance between the first sound outlet 112-1 and the tuning hole 113-3 is no greater than 14mm, the minimum distance from the boundary of the first acoustic cavity 111-1 to the first sound outlet 112-1 is no greater than 14mm, and the minimum distance from the boundary of the first acoustic cavity 111-1 to the tuning hole 113-3 is no greater than 14mm.

[0135] In this way, the sound output from the first sound outlet 112-1 can have a relatively flat phase curve at least in the frequency range below 1kHz, thereby ensuring that the headphones have a relatively flat output over a wider frequency range, which is beneficial for active noise cancellation in the headphones over a wider frequency range. In addition, as described in the aforementioned embodiments, the aperture of each small hole included in the first sound outlet 112-1 and the tuning hole 113-3 can be set to not less than 0.2mm.

[0136] Furthermore, in some embodiments, any of the aforementioned minimum distances can be set to no more than 10mm, no more than 8mm, no more than 6mm, or no more than 3.4mm, etc. For example, when the minimum distance is 10mm, the peak resonant frequency of the second resonant peak can be adjusted to 5.8kHz; when the minimum distance is 8mm, the peak resonant frequency of the second resonant peak can be adjusted to 6.7kHz; when the minimum distance is 6mm, the peak resonant frequency of the second resonant peak can be adjusted to 7.5kHz; and when the minimum distance is 3.4mm, the peak resonant frequency of the second resonant peak can be adjusted to 8.75kHz. Thus, by selecting and setting the minimum distance, the peak resonant frequency of the second resonant peak can be shifted as high as possible, further expanding the width of the flat region of the frequency response curve, enabling the headphones to achieve active noise cancellation over a wider frequency range.

[0137] In some embodiments, the ratio of the total area of ​​the tuning hole 113-3 to the total area of ​​the first sound outlet hole 112-1 can be set to less than 23%. Specifically, please refer to FIG16, which is a schematic diagram of the frequency response curves of the sound-emitting part 100 under different area ratios of the tuning hole 113-3 and the first sound outlet hole 112-1 according to some embodiments of this description. In the figure, on a reference plane perpendicular to the thickness direction, the total projected area of ​​the first sound outlet hole 112-1 on the reference plane is defined as S1, the total projected area of ​​the tuning hole 113-3 on the reference plane is defined as S2, and the ratio of the total projected area S1 of the tuning hole 113-3 to the total projected area S1 of the first sound outlet hole 112-1 is defined as SS.

[0138] As shown in Figure 16, as SS gradually increases, the high-frequency peak gradually moves to the back, and the sound pressure level of the output sound gradually decreases. The increase of SS means that the total opening area of ​​the tuning hole 113-3 increases, which can effectively achieve the pressure relief effect, thereby causing the high-frequency peak to shift to the back. However, at the same time, due to the increase in the total opening area of ​​the tuning hole 113-3, the sound leakage through the tuning hole 113-3 also increases, thereby reducing the sound pressure level of the sound output through the first sound outlet 112-1. As can be seen from Figure 16, when SS is from 0% (i.e., no tuning hole 113-3 is set) to 22.7%, the high-frequency peak shifts from 8.5kHz to 9.75kHz, and the sound pressure level of the output sound decreases by 1dB, which is within an acceptable range.

[0139] Therefore, setting the ratio of the total area of ​​the tuning hole 113-3 to the total area of ​​the first sound outlet hole 112-1 to less than 23% can effectively prevent excessive sound leakage from the tuning hole 113-3 due to the excessively large opening or area ratio of the tuning hole 113-3, thereby causing a decrease in the sound pressure level or volume of the first sound outlet hole 112-1.

[0140] For example, in some embodiments, the ratio of the total area of ​​the tuning hole 113-3 to the total area of ​​the first sound outlet 112-1 is set to 22.7%, thereby adjusting the peak resonant frequency of the second resonant peak to about 9.75kHz, further expanding the width of the flat area of ​​the frequency response curve of the sound output through the first sound outlet 112-1, and enabling the headphones to perform active noise cancellation in a wider frequency range.

[0141] In some embodiments, referring to Figure 17, the tuning hole 113-3 is positioned further away from the end wall 110e than the first sound outlet 112-1. Thus, in the wearing state, the tuning hole 113-3 is located further away from the external auditory canal 11 than the first sound outlet 112-1. In open-back applications, since the ambient noise received by the user's external auditory canal 11 is relatively large, improving the headphone's output performance helps the headphone actively reduce ambient noise. Therefore, by positioning the tuning hole 113-3 further away from the external auditory canal 11 than the first sound outlet 112-1, the sound output through the tuning hole 113-3 and the sound output through the first sound outlet 112-1 can cancel each other out in the far field, thereby reducing headphone leakage and ensuring the user's listening experience.

[0142] For example, on a reference plane perpendicular to the thickness direction, the length of the projection of the first acoustic cavity 111-1 along its major axis is not less than its width along its minor axis. For instance, the projected shape of the first acoustic cavity 111-1 can be a rectangle with a length greater than its width, or a square or circle with a length equal to its width. The projection of the first acoustic cavity 111-1 on the reference plane is divided into a first region and a second region along its length. The ratio of the length of the first region along its major axis to the length of the projection of the first acoustic cavity along its major axis can be set to less than 40%, for example, 38.3%. The projection of the tuning port 113-3 on the reference plane is located within the first region, and the projection of the first sound outlet port 112-1 on the reference plane is located within the second region.

[0143] Thus, by placing the tuning hole 113-3 and the first sound outlet hole 112-1 in different areas of the inner wall 110a corresponding to the first acoustic cavity 111-1, it is possible to ensure that the tuning hole 113-3 is located further away from the external auditory canal than the first sound outlet hole 112-1 when the tuning hole 113-3 is an array of small holes or a large area of ​​concentrated openings and is close to the first sound outlet hole 112-1, so that the tuning hole 113-3 and the first sound outlet hole 112-1 can be distinguished. For example, in the length or diameter direction of the first acoustic cavity 111-1, the holes in the area from the boundary of the first acoustic cavity 111-1 to a proportion of 38.3% can be regarded as the tuning hole 113-3.

[0144] It should be noted that the bold dashed lines in Figures 14 and 17 represent the projection boundary of the first acoustic cavity 111-1 on the reference plane; the bold solid lines with arrows in Figure 17 represent the approximate boundary between the first region and the second region in the projection shape of the first acoustic cavity 111-1, wherein the region to the left of the bold solid lines represents the first region, and the region to the right of the bold solid lines represents the second region.

[0145] In some embodiments, the first sound outlet 112-1 includes a plurality of first small holes arranged in an array, and the interval between the tuning hole 113-3 and the nearest first small hole is not less than 5 times the interval between adjacent first small holes.

[0146] In some embodiments, referring to Figures 14 and 17, when the first sound outlet 112-1 is a porous structure composed of multiple small holes arranged in an array, the diameter of the small holes located in the area of ​​the inner wall 110a directly in front of the external auditory canal 11 is set to be larger than the diameter of the small holes located in other areas of the inner wall 110a when worn. For example, among the multiple small holes in the sound outlet 112-1, the diameter of the small holes near the boundary of the first acoustic cavity 111-1 and the tuning hole 113-3 is smaller than the diameter of the small holes in other positions. In this way, by differentiating the diameters of the multiple small holes in the first sound outlet 112-1, the sound pressure level of the sound output by the earphone directly in front of the external auditory canal 11 can be increased, thereby ensuring the user's listening effect.

[0147] Please refer to Figures 5 and 6 together. The sound-generating assembly may also include a limiting component 130. The limiting component 130 can be used to seal and fix the speaker 120 within the first housing 110. In addition, the limiting component 130 can also cooperate with the speaker 120 and the corresponding housing sidewalls of the first housing 110 to seal and form an acoustic cavity. Specifically, the speaker 120 is arranged at intervals with the inner sidewall 110a and the outer sidewall 110b along the vibration direction, while the limiting component 130 positions and restricts the speaker 120 between the inner sidewall 110a and the outer sidewall 110b, thereby cooperating with the speaker 120 and the inner sidewall 110a to seal and form a first acoustic cavity 111-1, and cooperating with the speaker 120 and the outer sidewall 110b to seal and form a second acoustic cavity 111-2.

[0148] The limiting component 130 not only affects the structural relationship between the speaker 120 and the first housing 110, but also the structure of the acoustic cavity, thereby affecting the bandwidth of the active noise cancellation. Therefore, please refer to Figures 18 to 20. The following mainly describes the limiting component 130 and its related structures.

[0149] In some embodiments, referring to FIG5, the loudspeaker 120 includes a first diaphragm 121-1 and a second diaphragm 121-2 spaced vertically along the vibration direction, and a limiting component 130 is connected between the loudspeaker 120 and the first housing 110. Exemplarily, a portion of the limiting component 130 connects the loudspeaker 120 to the inner sidewall 110a of the first housing 110, and another portion connects the loudspeaker 120 to the outer sidewall 110b of the first housing 110.

[0150] When the loudspeaker 120 together with the limiting component 130 is installed in the first housing 110, the connection between the limiting component 130 and the housing sidewall of the first housing 110 (it should be noted that the connection can be adhesive, snap-fit, or elastic abutment, etc.) can be used to make the first diaphragm 121-1 and the inner sidewall 110a opposite each other in the vibration direction, and cooperate with the loudspeaker 120 and the inner sidewall 110a to form a first acoustic cavity 111-1. The limiting component 130 can also make the second diaphragm 121-2 and the outer sidewall 110b opposite each other in the vibration direction, and cooperate with the loudspeaker 120 and the outer sidewall 110b to form a second acoustic cavity 111-2.

[0151] Based on this, the limiting component 130 can be used to securely limit the speaker 120 to a predetermined position within the first housing 110, and to seal the speaker 120 and the first housing 110 to form a corresponding acoustic cavity, thus creating conditions for improving the output performance of the headphones. At the same time, the limiting component 130 can also be combined with the speaker 120 to form a relatively complete functional unit (i.e., a sound-generating component). This is beneficial for the disassembly and maintenance of the sound-generating part 100, and also for the design of related structures of the first housing 110 (such as the sound outlet, the tuning port 113-3, etc.) to meet the need for active noise cancellation in a wider frequency range.

[0152] In some embodiments, the limiting component 130 can be sealingly connected between the speaker 120 and the first housing 110. Specifically, a portion of the limiting component 130 is sealingly connected to the speaker 120, and another portion is sealingly connected to the first housing 110. Simultaneously, a sealed enclosure structure is formed between the inner sidewall 110a and the first diaphragm 121-1, and a sealed enclosure structure is formed between the outer sidewall 110b and the second diaphragm 121-2. Exemplarily, the limiting component 130 has a ring-shaped structure with a centrally located sound guide hole; in the vibration direction, the sound guide hole, the first sound outlet hole 112-1, the second sound outlet hole 112-2, the first diaphragm 121-1, and the second diaphragm 121-2 of the limiting component 130 can at least partially overlap.

[0153] In some embodiments, the limiting component 130 is fixedly connected to the speaker 120 to form an integral structure; the end of the limiting component 130 near the inner sidewall 110a in the vibration direction elastically abuts against the inner sidewall 110a, and the end near the outer sidewall 110b elastically abuts against the outer sidewall 110b. This allows the limiting component 130 to be combined with the speaker 120 to form a functional structure relatively independent of the first housing 110, which helps reduce the difficulty of disassembling and assembling the sound-emitting part 100.

[0154] In some embodiments, referring to Figures 5, 6, and 18 to 20, the limiting assembly 130 may include a first sealing ring 131 and a second sealing ring 132. The first sealing ring 131 elastically abuts against the inner sidewall 110a, and the second sealing ring 132 elastically abuts against the outer sidewall 110b. The first sealing ring 131 and the second sealing ring 132 seal and fix the speaker 120 within the first housing 110 from both sides in the vibration direction.

[0155] In some embodiments, the limiting component 130 may further include a second housing, and the speaker 120 is disposed within the second housing and sealed to the second housing. For ease of distinction and description, the shell wall of the second housing that is spaced apart from the inner sidewall 110b in the vibration direction is defined as the first transverse sidewall 1331, the shell wall of the second housing that is spaced apart from the outer sidewall 110b in the vibration direction is defined as the second transverse sidewall 1341, and the shell wall of the second housing that surrounds the vibration direction is defined as the longitudinal sidewall. It can also be understood that the first transverse sidewall 1331 faces the inner sidewall 110a (or speaker 120) and is disposed within the first acoustic cavity 111-1, the second transverse sidewall 1341 faces the outer sidewall 110b (or speaker 120) and is disposed within the second acoustic cavity 111-2, and the speaker 120 is located between the first transverse sidewall 1331 and the second transverse sidewall 1341 in the vibration direction. In addition, one end of the first sealing ring 131 is fixed to the first transverse sidewall 1331 in the vibration direction, and the other end abuts against the inner sidewall 110a; one end of the second sealing ring 132 is fixed to the second transverse sidewall 1341 in the vibration direction, and the other end abuts against the outer sidewall 110b.

[0156] Referring to Figure 5, based on the first sealing ring 131 and the second sealing ring 132, the sound-generating component can be sealed and fixed inside the first housing 110 (i.e., the accommodating cavity) by means of interference fit, for example, the first sealing ring 131 elastically abuts against the inner sidewall 110a, while the second sealing ring 132 elastically abuts against the outer sidewall 110b; in this way, the speaker 120 is sealed and fixed inside the first housing 110 from both sides in the vibration direction using the first sealing ring 131 and the second sealing ring 132, thereby achieving the sealing of the first acoustic cavity 111-1 on the side of the first transverse sidewall 1331 near the inner sidewall 110a, and achieving the sealing of the second acoustic cavity 111-2 on the side of the second transverse sidewall 1341 near the outer sidewall 110b.

[0157] It should be noted that the "boundary of the first acoustic cavity 111-1" mentioned in the foregoing embodiments can be defined by the first sealing ring 131. That is, it can be understood that the projection of the first sealing ring 131 onto the reference plane perpendicular to the vibration direction is the boundary of the first acoustic cavity 111-1.

[0158] In some embodiments, the deformation resistance of the first sealing ring 131 and the second sealing ring 132 is less than that of the second housing. For example, the first sealing ring 131 and the second sealing ring 132 can be made of elastic materials such as silicone, while the second housing can be made of metal materials such as aluminum alloy or other materials such as plastic with a material hardness greater than that of the sealing ring.

[0159] For example, the first sealing ring 131 and the second sealing ring 132 are made of elastic materials such as silicone, and the first sealing ring 131 and the second sealing ring 132 can be integrally molded into the second housing by injection molding, die-cutting or other methods. In this way, the limiting component 130 can be constructed into a relatively independent and complete structural component, which helps to reduce the difficulty of disassembling and assembling the sound-generating component and the sound-generating part 100, and enhances the structural stability of the sound-generating component and even the sound-generating part 100.

[0160] In some embodiments, a reinforcing structure is provided at the junction of the second housing and the first sealing ring 131 (and the second sealing ring 132). The reinforcing structure may be a serrated structure, a hole structure, etc., provided on the first transverse sidewall 1331 or the second transverse sidewall 1341. The reinforcing structure enhances the stability of the connection between the first sealing ring 131 (and the second sealing ring 132) and the second housing structure, and prevents the sealing ring from falling off when the sound-generating part 100 is disassembled or assembled.

[0161] The sound-generating assembly can be inserted into the first housing 110 as a whole through the first opening 1101. After the sound-generating assembly is assembled in place relative to the first housing 110, the first sealing ring 131 and the second sealing ring 132 seal and fix the speaker 120 in the first housing 110 from both sides in the vibration direction. The first acoustic cavity 111-1 is sealed on the side of the first transverse sidewall 1331 near the inner sidewall 110a, and the second acoustic cavity 111-2 is sealed on the side of the second transverse sidewall 1341 near the outer sidewall 110b. The assembly is achieved in a relatively simple way, which is conducive to improving assembly efficiency.

[0162] In some embodiments, referring to Figures 18 to 20, the second housing is a split structure, including a first cover 133 and a second cover 134. One end of the speaker 120 in the vibration direction extends into the first cover 133, and the other end extends into the second cover 134. Alternatively, the first cover 133 and the second cover 134 can be understood as respectively covering or shielding the opposite ends of the speaker 120 in the vibration direction. The side wall of the first cover 133 located between the speaker 120 and the inner side wall 110a is the first transverse side wall 1331, and the side wall of the second cover 134 located between the speaker 120 and the outer side wall 110b is the second transverse side wall 1341. The side wall of the first cover 133 that surrounds the speaker 120 in the vibration direction and is fixedly connected to it is the first longitudinal side wall 1332, and the side wall of the second cover 134 that surrounds the speaker 120 in the vibration direction and is fixedly connected to it is the second longitudinal side wall 1342.

[0163] The first longitudinal sidewall 1332 and the second longitudinal sidewall 1342 are spaced apart along the vibration direction, forming a surrounding accommodating gap 130-4 between the first and second masks. The second microphone assembly can be at least partially embedded in the accommodating gap 130-4 to fully utilize the structural space, improve the structural compactness of the sound-generating assembly, and facilitate the miniaturization of the sound-generating part 100 or even headphones. In addition, wires, ribbon cables, flexible printed circuit boards (FPCs) can also be housed and fixed within the accommodating gap 130-4.

[0164] In some embodiments, the first mask 133 and the first sealing ring 131 can be constructed as independent and complete structural components, and the second mask 134 and the second sealing ring 132 can be constructed as independent and complete structural components, which is beneficial for the assembly and disassembly of the speaker 120 and the limiting component 130, and reduces the difficulty of assembling and disassembling the sound-generating component.

[0165] In some embodiments, the limiting component 130 may omit the second housing, and a sealed connection may be directly established between the speaker 120 and the first housing 110 using the first sealing ring 131 and the second sealing ring 132. For example, the first sealing ring 131 is clamped and fixed between the speaker 120 and the inner sidewall 110a, and together with the speaker 120 and the inner sidewall 110a, forms a first acoustic cavity 111-1; the second sealing ring 132 is clamped and fixed between the speaker 120 and the outer sidewall 110b, and together with the speaker 120 and the outer sidewall 110b, forms a second acoustic cavity 111-2. In this case, the first sealing ring 131 and the second sealing ring 132 may adopt an annular structure, and corresponding sound guide holes may be formed by openings in the first sealing ring 131 and the second sealing ring 132.

[0166] In other embodiments, the limiting component 130 may omit the first sealing ring 131 and the second sealing ring 132, and utilize the interference fit between the second housing (e.g., the first mask 133 and the second mask 134) and the first housing 110 (e.g., the inner sidewall 110a and the outer sidewall 110b) to form the first acoustic cavity 111-1 and the second acoustic cavity 111-2.

[0167] In other embodiments, the limiting component 130 may also adopt other suitable structures, as long as it can securely fix the speaker 120 within the first housing 110, or enable the speaker 120 to divide the accommodating cavity into a first acoustic cavity 111-1 and a second acoustic cavity 111-2. These will not be elaborated upon here.

[0168] The sound guide holes of the limiting component 130 may include a first sound guide hole 130-1 connecting the spaces on both sides of the first transverse sidewall 1331, and a second sound guide hole 130-2 connecting the spaces on both sides of the second transverse sidewall 1341. The first sound guide hole 130-1 conducts through the first acoustic cavity 111-1. This can also be understood as the first acoustic cavity 111-1 including the cavity space between the first transverse sidewall 1331 and the inner sidewall 110a, and the cavity space between the first transverse sidewall 1331 and the speaker 120 (e.g., the second diaphragm 121-1). These two cavity spaces located on both sides of the first transverse sidewall 1331 are connected by the first sound guide hole 130-1 to form the complete first acoustic cavity 111-1. Similarly, the second sound guide hole 130-2 conducts through the second acoustic cavity 111-2.

[0169] Based on this, using the second housing as the outer protective structure of the speaker 120 provides a relatively stable structural assembly space for the speaker. This not only facilitates the construction of the sound-generating components into a complete functional unit, but also promotes the miniaturization and weight reduction of the sound-generating components or the sound-generating section 100. For example, the second housing can be made of metal, thereby ensuring the mechanical strength of the second housing while making the shell wall thinner and lighter. Simultaneously, it also facilitates the design of the internal acoustic structure of the sound-generating section 100, providing support for active noise cancellation and other functions.

[0170] In some embodiments, on a reference plane perpendicular to the vibration direction, the projections of the sound guide hole, the first sound outlet hole 112-1, the second sound outlet hole 112-2, the first diaphragm 121-1, and the second diaphragm 121-2 of the limiting component 130 at least partially overlap to ensure that the sound output of the speaker 120 is delivered to the outside of the first housing 110.

[0171] For example, in some embodiments, the projection of the first sound outlet 112-1 can fall within the projection of the first sound guide 130-1 on a reference plane perpendicular to the vibration direction. Alternatively, in some embodiments, the projection of the first sound outlet 112-1 and the projection of the first sound guide 130-1 have a first overlapping area on the reference plane perpendicular to the vibration direction, and the area of ​​the first overlapping area is not less than 80% of the projected area of ​​the first sound outlet 112-1. This arrangement allows the air pushed by the diaphragm in the first sound guide 130-1 of the limiting component 130 to be smoothly pushed out from the first sound outlet 112-1, ensuring the acoustic output of the speaker 120 and providing support for shifting the peak resonant frequency of the first resonant peak of the sound output from the first sound outlet 112-1 as low as possible and the peak resonant frequency of the second resonant peak as high as possible.

[0172] Preferably, in some embodiments, the projection of the second sound outlet 112-2 can fall within the projection of the second sound guide 130-2 on a reference plane perpendicular to the vibration direction. Alternatively, in some embodiments, on a reference plane perpendicular to the vibration direction, there is a second overlapping area between the projection of the second sound outlet 112-2 and the projection of the second sound guide 130-2, and the area of ​​the second overlapping area is not less than 80% of the projected area of ​​the second sound outlet 112-2. This arrangement allows the air pushed by the diaphragm in the second sound guide 130-2 of the limiting component 130 to be smoothly pushed out from the second sound outlet 112-2, ensuring the acoustic output of the speaker 120.

[0173] Similarly, in some embodiments, the projection of the first sound guide hole 130-1 can fall within the projection of the first diaphragm 121-1 on a reference plane perpendicular to the vibration direction. Alternatively, in some embodiments, on a reference plane perpendicular to the vibration direction, there is a third overlapping region between the projection of the first diaphragm 121-1 and the projection of the first sound guide hole 130-1, and the area of ​​the third overlapping region is not less than 80% of the projected area of ​​the first sound guide hole 130-1. This arrangement ensures that when the first diaphragm 121-1 vibrates, the air propelled by the first diaphragm 121-1 can smoothly enter the first sound guide hole 130-1 of the limiting component 130, maximizing the acoustic output of the speaker 120.

[0174] Preferably, in some embodiments, the projection of the second sound guide hole 130-2 can fall within the projection of the second diaphragm 121-2 on a reference plane perpendicular to the vibration direction. Alternatively, in some embodiments, on a reference plane perpendicular to the vibration direction, there is a fourth overlapping region between the projection of the second diaphragm 121-2 and the projection of the second sound guide hole 130-2, and the area of ​​the fourth overlapping region is not less than 80% of the projected area of ​​the second sound guide hole 130-2. This arrangement ensures that when the second diaphragm 121-2 vibrates, the air propelled by the second diaphragm 121-2 can smoothly enter the second sound guide hole 130-2 of the limiting component 130, maximizing the acoustic output of the speaker 120.

[0175] In some embodiments, the first transverse sidewall 1331 and the first sound guide hole 130-1, the second transverse sidewall 1341 and the second sound guide hole 130-2 can provide support for adjusting the resonant frequency, acoustic impedance ratio and sound pressure level of the sound output from the corresponding acoustic cavity, so as to enhance the active noise reduction effect.

[0176] For example, the first sound guide hole 130-1 is formed by the cooperation of the opening of the first sealing ring 131 and the opening of the first transverse sidewall 1331. On a reference plane perpendicular to the vibration direction, the projections of the openings of the first transverse sidewall 1331, the first sound outlet hole 112-1, and the first sealing ring 131 form a fifth overlapping region. The area proportion of the projection of the opening of the first transverse sidewall 1331 in the fifth overlapping region is greater than the area proportion of the projection of the first sound outlet hole 112-1. For example, on the reference plane, within the fifth overlapping region, the area proportion of the projection of the opening of the first transverse sidewall 1331 can be greater than 30% (e.g., greater than 80%), while the area proportion of the projection of the first sound outlet hole 112-1 can be between 20% and 30%. This minimizes the impact on sound output caused by the small opening areas of the first sound guide hole 130-1 and the second sound guide hole 130-2.

[0177] Preferably, the second sound guide hole 130-2 includes the opening of the second sealing ring 132 and the opening of the second transverse sidewall 1341. On a reference plane perpendicular to the vibration direction, the projections of the opening of the second transverse sidewall 1341, the projection of the second sound outlet hole 112-2, and the projection of the opening of the second sealing ring 132 form a sixth overlapping region. The area proportion of the projection of the opening of the second transverse sidewall 1341 in the sixth overlapping region is greater than the area proportion of the projection of the second sound outlet hole 112-2. For example, on the reference plane, within the sixth overlapping region, the area proportion of the projection of the opening of the second transverse sidewall 1341 can be greater than 30% (e.g., greater than 80%), while the area proportion of the projection of the second sound outlet hole 112-2 can be between 20% and 30%. This minimizes the impact on sound output caused by the small opening areas of the first sound guide hole 130-1 and the second sound guide hole 130-2.

[0178] In some embodiments, please refer to Figures 18 and 19. The second housing has a rib structure, which is disposed on the first transverse sidewall 1331 and the second transverse sidewall 1341. For ease of distinction and description, the rib structure of the first transverse sidewall 1331 is defined as the first rib structure 1334, and the rib structure of the second transverse sidewall 1341 is defined as the second rib structure 1344. The first rib structure 1334 is located in the first sound guide hole 130-1, and the second rib structure 1344 is located in the second sound guide hole 130-2.

[0179] The first rib structure 1334 can be used to support and fix the first acoustic barrier 160-1 in the aforementioned embodiment within the first acoustic cavity 111-1. For example, the first acoustic barrier 160-1 can be bonded and fixed to the first rib structure 1334, covering the first sound guide hole 130-1 and fixed to the side of the first transverse sidewall 1331 facing the inner sidewall 110a. The second rib structure 1344 can be used to support and fix the second acoustic barrier 160-2 in the aforementioned embodiment within the second acoustic cavity 111-2. For example, the second acoustic barrier 160-2 can be bonded and fixed to the second rib structure 1344, covering the second sound guide hole 130-2 and fixed to the side of the second transverse sidewall 1341 facing the outer sidewall 110b.

[0180] On the one hand, the rib structure can be used to adjust the opening area, shape and distribution of the corresponding sound guide holes, so as to adjust the acoustic characteristics or sound output of the corresponding acoustic cavity. For example, the rib structure can be used to construct the corresponding sound guide holes into a mesh hole structure. On the other hand, the acoustic barrier can be fixed to the corresponding rib structure and the corresponding side wall of the limiting component 130 by means of bonding, welding or other methods, so as to avoid the acoustic barrier from shaking due to air vibration when the speaker 120 is working, thereby avoiding adverse effects on the sound output (such as frequency response curve, etc.) and ensuring the active noise reduction effect.

[0181] In some embodiments, a plurality of first rib structures 1334 may be provided on the first transverse sidewall 1331. The plurality of first rib structures 1334 may be spaced apart along the length of the sound-emitting part 100. The number of first rib structures 1334 may be between 2 and 5, for example, 2, 3, 4 or 5, so as to control the total area of ​​the first rib structures 1334 within a reasonable range. In some embodiments, the upper dimension of a single first rib structure 1334 along the length of the sound-emitting part 100 (i.e., the width of a single first rib structure 1334) may be between 0.5mm and 1.5mm. For example, the upper dimension of a single first rib structure 1334 along the length of the sound-emitting part 100 may be 0.5mm, 0.8mm, 1.0mm, 1.2mm or 1.5mm, so as to control the total area of ​​the first rib structures 1334 within a reasonable range.

[0182] This configuration serves two purposes. First, it ensures a relatively large fixing area between the first acoustic barrier 160-1 and the first transverse sidewall 1331, allowing the first acoustic barrier 160-1 to be reliably fixed to the first transverse sidewall 1331 and preventing vibration of the first acoustic barrier 160-1 due to air vibration during speaker 120 operation. Second, it prevents the total area of ​​the first rib structure 1334 from becoming too large, which would affect the opening area of ​​the first sound guide hole 130-1 and result in an excessively small opening area.

[0183] In some embodiments, a plurality of second rib structures 1344 may be provided on the second transverse sidewall 1341. These second rib structures 1344 may be spaced apart along the length of the sound-emitting portion 100, and the number of second rib structures 1344 may be between 2 and 5, for example, 2, 3, 4, or 5, to control the total area of ​​the second rib structures 1344 within a reasonable range. In some embodiments, the upper dimension of a single second rib structure 1344 along the length of the sound-emitting portion 100 (i.e., the width of a single second rib structure 1344) may be between 0.5 mm and 1.5 mm. For example, the upper dimension of a single second rib structure 1344 along the length of the sound-emitting portion 100 may be 0.5 mm, 0.8 mm, 1.0 mm, 1.2 mm, or 1.5 mm, to control the total area of ​​the second rib structures 1344 within a reasonable range.

[0184] This configuration serves two purposes. First, it ensures a relatively large fixing area between the second acoustic barrier 160-2 and the second transverse sidewall 1341, allowing the second acoustic barrier 160-2 to be reliably fixed to the second transverse sidewall 1341 and preventing vibration of the second acoustic barrier 160-2 due to air vibration during speaker 120 operation. Second, it prevents the total area of ​​the second rib structure 1344 from becoming too large, which would affect the opening area of ​​the second sound guide hole 130-2 and result in an excessively small opening area.

[0185] In some embodiments, referring to FIG20, when the second housing has a first transverse sidewall 1331 and a second transverse sidewall 1341, the minimum distance between the first transverse sidewall 1331 and the center of the main body region 121a of the first diaphragm 121-1 is greater than the maximum amplitude of the vibration of the main body region 121a toward the inner sidewall 110a, and the minimum distance between the second transverse sidewall 1341 and the center of the main body region 121a of the second diaphragm 121-2 is greater than the maximum amplitude of the vibration of the main body region 121a toward the outer sidewall 110b.

[0186] Therefore, by limiting the distance between the diaphragm amplitude and the corresponding sidewall, collisions with the limiting component 130 during diaphragm vibration can be avoided, thus ensuring sound output performance.

[0187] In addition, in some embodiments where the second housing is omitted or the second housing does not have a first lateral sidewall 1331 or a second lateral sidewall 1341, in order to avoid the diaphragm colliding with the corresponding housing sidewall in the first housing 110 during vibration, the minimum distance in the vibration direction between the center of the main body region 121a of the first diaphragm 121-1 and the inner sidewall 110a is set to be greater than the maximum amplitude of the vibration of the main body region 121a toward the inner sidewall 110a, and the minimum distance in the vibration direction between the center of the main body region 121a of the second diaphragm 121-2 and the outer sidewall 110b is set to be greater than the maximum amplitude of the vibration of the main body region 121a toward the outer sidewall 110b.

[0188] In some embodiments, referring to Figures 19 and 20, the first transverse sidewall 1331 and the second transverse sidewall 1341 each have a central portion 13a and an arcuate portion 13b surrounding the central portion 13a. One end of the arcuate portion 13b away from the central portion 13a is connected to the longitudinal sidewall of the second housing. In the vibration direction, the central portion 13a of the first transverse sidewall 1331 faces the main body region 121a of the first diaphragm 121-1 (at this time, the first sound guide hole 130-1 can be disposed on the first transverse sidewall). Inside the center portion 13a of the second transverse sidewall 1331, the arc-shaped portion 13b of the first transverse sidewall 1331 faces the folded ring region 121b of the first diaphragm 121-1, the center portion 13a of the second transverse sidewall 1341 faces the main body region 121a of the second diaphragm 121-2 (at this time, the second sound guide hole 130-2 can be set in the center portion 13a of the second transverse sidewall 1341), and the arc-shaped portion 13b of the second transverse sidewall 1341 faces the folded ring region 121b of the second diaphragm 121-2.

[0189] On one hand, a second clearance space 130-5 can be formed between the folded loop region 121b of the first diaphragm 121-1 and the arcuate portion 13b of the first transverse sidewall 1331. When the first diaphragm 121-1 vibrates, the second clearance space 130-5 avoids the folded loop region 121b of the first diaphragm 121-1. Simultaneously, a second clearance space 130-6 can also be formed between the folded loop region 121b of the second diaphragm 121-2 and the arcuate portion 13b of the second transverse sidewall 1341. When the second diaphragm 121-2 vibrates, the second clearance space 130-6 avoids the folded loop region 121b of the second diaphragm 121-2. In summary, the clearance spaces prevent the folded loop region 121b of the diaphragm from colliding with the limiting component 130 during vibration, thus ensuring sound output performance.

[0190] On the other hand, compared to the solution where the transverse and longitudinal sidewalls are connected at right angles, the arc-shaped portion 13b forms an arc-shaped transition structure between the transverse and longitudinal sidewalls. This allows the first housing to be constructed in a form that adapts to the second housing, making the corner areas between adjacent sidewalls of the first housing more curved and smooth, avoiding more prominent sharp edges. In this way, without affecting the diaphragm vibration, the comfort of the sound-emitting part 100 or the headphones can be improved, and the appearance of the sound-emitting part 100 can also be improved. At the same time, it is also convenient to adapt the longitudinal sidewall to the outer contour structure of the speaker 120. For example, the longitudinal sidewall can be structurally adapted and fixed to the bracket in the speaker 120, so that the speaker 120 can be stably positioned and fixed inside the second housing.

[0191] In some embodiments, a first annular platform 1333 is provided at the connection between the arcuate portion 13b of the first transverse sidewall 1331 and the first longitudinal sidewall 1332, and a second annular platform 1343 is provided at the connection between the arcuate portion 13b of the second transverse sidewall 1341 and the second longitudinal sidewall 1342. The first annular platform 1333 and the second annular platform 1343 abut against the two sides of the speaker 120 along the vibration direction, and a sealant is provided in the abutment area.

[0192] Specifically, the first annular platform 1333 can abut against the circumferential edge of the first diaphragm 121-1, thereby sealing the first acoustic cavity 111-1 on the side of the first transverse sidewall 1331 facing the first diaphragm 121-1. For example, the circumferential edge of the first annular platform 1333 and / or the first diaphragm 121-1 can be pre-applied with sealant. When the first mask 133 is assembled relative to the speaker 120, the first acoustic cavity 111-1 is sealed on the side of the first transverse sidewall 1331 facing the first diaphragm 121-1, thus enabling assembly in a relatively simple manner.

[0193] The second annular platform 1343 can abut against the circumferential edge of the second diaphragm 121-2, thereby sealing the second acoustic cavity 111-2 on the side of the second transverse sidewall 1341 facing the second diaphragm 121-2. For example, the circumferential edge of the second annular platform 1343 and / or the second diaphragm 121-2 can be pre-applied with sealant, and when the second cover 134 is assembled relative to the speaker 120, the second acoustic cavity 111-2 is sealed on the side of the second transverse sidewall 1341 facing the second diaphragm 121-2, thus enabling assembly in a relatively simple manner.

[0194] As in some of the aforementioned embodiments, the loudspeaker 120 may be a dual-diaphragm loudspeaker. Referring to Figure 20, the loudspeaker 120 includes a first diaphragm 121-1, a second diaphragm 121-2, a magnetic circuit assembly, a voice coil assembly, etc. The first diaphragm 121-1 and the second diaphragm 121-2 are spaced apart and opposite each other in the vibration direction. The voice coil assembly and the magnetic circuit assembly are arranged between the first diaphragm 121-1 and the second diaphragm 121-2. At least a portion of the voice coil assembly extends into the magnetic gap of the magnetic circuit assembly, and at least one of the first diaphragm 121-1 and the second diaphragm 121-2 is connected to the voice coil assembly. This allows the voice coil assembly to drive the first diaphragm 121-1 and the second diaphragm 121-2 to vibrate synchronously and in the same direction and generate sound through the cooperation of the magnetic circuit assembly and the voice coil assembly.

[0195] Therefore, by having the first diaphragm 121-1 and the second diaphragm 121-2 vibrate synchronously in the same direction, the consistency and stability of the speaker 120 vibration are improved. This helps the peak resonant frequency of the low-frequency resonant peak (e.g., the first resonant peak) of the headphone output to shift to a lower frequency and the peak resonant frequency of the high-frequency resonant peak (e.g., the second resonant peak) to a higher frequency, thereby enabling the headphone to have a flatter output over a wider frequency range, thus enhancing the active noise cancellation effect.

[0196] Besides structural features such as the sound outlet and tuning port, the structure and performance of the speaker 120 itself also have a crucial impact on the active noise cancellation of the headphones. In some embodiments, the first diaphragm 121-1 and the second diaphragm 121-2 can be indirectly connected through a voice coil assembly to ensure the consistency of the synchronous and co-directional vibration of the two diaphragms, thereby providing support for enhancing the active noise cancellation effect.

[0197] The following mainly introduces the relevant structure of the dual-diaphragm loudspeaker 120 when the first diaphragm 121-1 and the second diaphragm 121-2 are indirectly connected through a voice coil assembly.

[0198] In some embodiments, referring to Figures 20 and 21, the voice coil assembly includes a first voice coil 123-1 and a second voice coil 123-2, which are arranged vertically in the vibration direction. The end of the first voice coil 123-1 away from the second voice coil 123-2 is connected to a first diaphragm 121-1, and the end of the second voice coil 123-2 away from the first voice coil 123-1 is connected to the second diaphragm 121-2. The first voice coil 123-1 drives the first diaphragm 121-1 to vibrate, and the second voice coil 123-2 drives the second diaphragm 121-2 to vibrate, causing the first diaphragm 121-1 and the second diaphragm 121-2 to vibrate synchronously and in the same direction.

[0199] Exemplarily, in some embodiments, the first voice coil 123-1 and the second voice coil 123-2 are connected at their ends that are close to each other in the vibration direction. The voice coil assembly also includes a connector (for ease of distinction and description, this connector is defined as the first connector 127), which connects the first voice coil 123-1 and the second voice coil 123-2; alternatively, the first voice coil 123-1 and the second voice coil 123-2 can be directly bonded together using adhesive or similar methods. In this case, the structural connection between the first voice coil 123-1 and the second voice coil 123-2 is equivalent to constructing an integrated voice coil assembly, thereby achieving an indirect connection between the first diaphragm 121-1 and the second diaphragm 121-2.

[0200] Firstly, the first diaphragm 121-1 and the second diaphragm 121-2 are connected by an integrated voice coil assembly, allowing the first voice coil 123-1 and the second voice coil 123-2 to share a magnetic circuit assembly. With the cooperation of the magnetic circuit assembly, the consistency of vibration of the first diaphragm 121-1 and the second diaphragm 121-2 (i.e., synchronous and co-directional vibration) can be ensured, and the driving force of the voice coil assembly can be enhanced. This is beneficial for the headphones to have a flatter output over a wider frequency range, ensuring the active noise cancellation effect.

[0201] Secondly, when the first diaphragm 121-1 and the second diaphragm 121-2 vibrate synchronously and in the same direction, the volume of the common cavity 111-3 formed between the two will not change with the vibration of the diaphragms. The gas in the common cavity 111-3 will not only not hinder the vibration of the first diaphragm 121-1 and the second diaphragm 121-2, but the gas can also move back and forth with the vibration of the two diaphragms as an accompanying mass. This is beneficial to improving the consistency of the vibration of the first diaphragm 121-1 and the second diaphragm 121-2, thereby improving the output performance of the headphones and ensuring the effect of active noise cancellation of the headphones.

[0202] Thirdly, the connection between the first voice coil 123-1 and the second voice coil 123-2 can ensure the consistency of vibration between the first diaphragm 121-1 and the second diaphragm 121-2, and can also flexibly adjust the winding direction of the voice coil coil and the direction of the working current, so that the voice coil assembly can use the magnetic field distribution of the magnetic circuit assembly.

[0203] Fourth, in scenarios where headphones have high waterproofing requirements, such as headphones worn while swimming, the first housing 110 often needs to be fully sealed. In this case, if the first diaphragm 121-1 and the second diaphragm 121-2 vibrate in opposite directions, the gas in the common cavity 111-3 formed between the first diaphragm 121-1 and the second diaphragm 121-2 will be difficult to expel. This will interfere with the vibration of the first diaphragm 121-1 and the second diaphragm 121-2, thereby affecting the output performance of the headphones. Therefore, using the first voice coil 123-1 and the second voice coil 123-2 to drive the first diaphragm 121-1 and the second diaphragm 121-2 to vibrate synchronously and in the same direction can support the full sealing treatment of the first housing 110 or the speaker itself.

[0204] In some embodiments, please refer to Figures 20 and 21. The magnetic circuit assembly includes an outer magnetic circuit component 122-1, an inner magnetic circuit component 122-2, and a magnetic circuit connector 122-3. The outer magnetic circuit component 122-1 surrounds the outer periphery of the inner magnetic circuit component 122-2 and is connected to the inner magnetic circuit component 122-2 through the magnetic circuit connector 122-3, thereby forming a magnetic gap of the magnetic circuit assembly between the outer magnetic circuit component 122-1 and the inner magnetic circuit component 122-2.

[0205] Accordingly, referring to Figures 22 and 23, the first voice coil 123-1 and the second voice coil 123-2 can adopt an unequal diameter structure. For example, on a reference plane perpendicular to the vibration direction, there is a gap between the orthographic projection of the first voice coil 123-1 and the orthographic projection of the second voice coil 123-2 in the major axis direction or the minor axis direction. This results in a portion of the first voice coil 123-1 and the second voice coil 123-2 that are connected to each other and another portion that is separated from each other, thus allowing the gap between them to be used as a basis for... The presence of the first voice coil 123-1 and the second voice coil 123-2 forms a clearance channel 123-3 that allows the magnetic circuit connector 122-3 to pass through the voice coil assembly; it can also be understood that, based on a reference plane perpendicular to the vibration direction, the orthographic projection of the first voice coil 123-1 in the reference plane and the orthographic projection of the second voice coil 123-2 in the reference plane can be partially connected or partially overlapped, thereby forming a clearance channel 123-3 at the separation of the first voice coil 123-1 and the second voice coil 123-2.

[0206] For example, referring to Figure 22, the outline shape of the loudspeaker 120 is non-circular, such as rectangular, elliptical, etc. In this case, the sidewalls of the first voice coil 123-1 and the second voice coil 123-2 in the long axis direction can be defined as long sidewalls, and the sidewalls in the short axis direction can be defined as short sidewalls. The orthographic projection of the long sidewall of the first voice coil 123-1 on the reference plane is connected to or at least partially overlaps with the orthographic projection of the long sidewall of the second voice coil 123-2 on the reference plane, while the orthographic projection of the short sidewall of the first voice coil 123-1 on the reference plane is separate from the orthographic projection of the short sidewall of the second voice coil 123-2 on the reference plane. In this way, a clearance channel 123-3 can be formed between the short sidewall of the first voice coil 123-1 and the short sidewall of the second voice coil 123-2.

[0207] For example, the outline of the sound-emitting part 100 or the loudspeaker 120 is approximately circular. In this case, the first voice coil 123-1 and the second voice coil 123-2 can be connected by the first connector 127, so that the orthographic projection of the first voice coil 123-1 on the reference plane is the first ring, and the orthographic projection of the second voice coil 123-2 on the reference plane is the second ring. In the case that the first ring and the second ring have different diameters, the third connector is used to realize the partial connection and partial separation between the first voice coil 123-1 and the second voice coil 123-2, thereby forming the avoidance channel 123-3.

[0208] Thus, by setting the first voice coil 123-1 and the second voice coil 123-2 as unequal diameter structures with locally unequal dimensions, the clearance channel 123-3 formed between the first voice coil 123-1 and the second voice coil 123-2 can provide clearance space for the magnetic circuit connector 122-3. This is equivalent to placing the voice coil assembly within the same magnetic gap of the magnetic circuit assembly. This not only enhances the structural stability of the magnetic circuit assembly itself, supporting the rapid assembly of the speaker 120, but also helps reduce assembly difficulty and cost, and avoids the voice coil assembly from touching the magnetic circuit assembly during movement, thus preventing it from affecting the sound output. At the same time, the outer magnetic circuit component 122-1 adopts a ring structure surrounding the inner magnetic circuit component 122-2, which allows the magnetic circuit assembly to have a larger design size. By increasing the volume of the magnet, the driving force of the voice coil assembly can be increased, thereby improving the sound output performance of the speaker 120.

[0209] In some embodiments, referring to Figure 22, the overall outer contour shape of the loudspeaker 120 is set to a rectangle, racetrack shape, or ellipse, etc., that matches the contour shape of the first housing 110 or the sound-emitting part 100. In this case, the length of the long sidewall of the first voice coil 123-1 in the long axis direction is greater than the width of the short sidewall of the first voice coil 123-1 in the short axis direction, and the length of the long sidewall of the second voice coil 123-2 in the long axis direction is greater than the width of the short sidewall of the second voice coil 123-2 in the short axis direction. At the same time, the length of the long sidewall of the first voice coil 123-1 in the long axis direction can be set to be less than the length of the long sidewall of the second voice coil 123 in the long axis direction. In this case, the long sidewall of the first voice coil 123-1 and the short sidewall of the second voice coil 123-2 can be connected by the first connector 127; thus, a clearance channel 123-2 can be naturally formed between the short sidewalls of the two voice coils.

[0210] Accordingly, the length of the magnetic circuit assembly in the long axis direction is greater than its width in the short axis direction, and the short side of the outer magnetic circuit component 122-1 and the short side of the inner magnetic circuit component 122-2 are connected by the magnetic circuit connector 122-3, so that the magnetic circuit assembly is constructed with no connection on the long side and a connection on the short side. That is, the magnetic circuit connector 122-3 passes through the magnetic gap between the short side of the inner magnetic circuit component 122-2 and the short side of the outer magnetic circuit component 122-1.

[0211] On the one hand, while maintaining the integrated structure of the voice coil assembly, connecting the long sidewalls of the two voice coils enhances the structural stability of the voice coil assembly itself and improves the vibration consistency between the first diaphragm 121-1 and the second diaphragm 121-2, creating conditions for ensuring active noise cancellation. On the other hand, the structure of the magnetic circuit assembly with no long side connection and a short side connection facilitates the formation of a strong and uniform magnetic field between the long side of the inner magnetic circuit component 122-2 and the long side of the outer magnetic circuit component 122-1. This allows the magnetic field to pass through the magnetic gap as much as possible, achieving full utilization of the magnetic field and effectively enhancing the driving force of the voice coil assembly.

[0212] In other embodiments, the first voice coil 123-1 and the second voice coil 123-2 may also have the same diameter. Specifically, on a reference plane perpendicular to the vibration direction, the orthographic projection of the first voice coil 123-1 coincides with the orthographic projection of the second voice coil 123-2. In this case, on a reference plane parallel to the vibration direction, there is a gap in the vibration direction between the orthographic projection of the first voice coil 123-1 and the orthographic projection of the second voice coil 123-2, thereby forming a clearance channel 123-3 between them based on the existence of the gap. In this case, after the magnetic circuit connector 122-3 passes through the clearance channel 123-3 in a direction perpendicular to the vibration direction, both ends of the magnetic circuit connector 122-3 are connected to the inner magnetic circuit component 122-2 and the outer magnetic circuit component 122-1, respectively.

[0213] As mentioned above, the first voice coil 123-1 and the second voice coil 123-2 can be connected by the first connector 127. In some embodiments, please refer to FIG23, the first voice coil 123-1 and the second voice coil 123-2 each include a voice coil skeleton 123a and a coil 123b wound around the outer periphery of the voice coil skeleton; for ease of distinction and description, the voice coil skeleton 123a and the coil 123b of the first voice coil 123-1 are respectively defined as the first skeleton and the first coil, and the voice coil skeleton and the coil of the second voice coil 123-2 are respectively defined as the second skeleton and the second coil; wherein, the first skeleton and the second skeleton are respectively arranged around the inner magnetic circuit component 122-2 between the inner magnetic circuit component 122-2 and the outer magnetic circuit component 122-1, and the first connector 127 is connected between the first skeleton and the second skeleton, thereby realizing the separation of the coils of the two voice coils and forming a clearance channel 123-3 between the two voice coil skeletons 127-1.

[0214] Based on the connection relationship between the first skeleton, the second skeleton and the first connector 127, a skeleton structure of the voice coil is formed. Due to the high structural strength and strong connection stability of the skeleton structure, the vibration consistency between the first diaphragm 121-1 and the second diaphragm 121-2 can be further guaranteed, and it is applicable to voice coils 123-1 and second voice coils 123-2 of different sizes.

[0215] In some embodiments, the voice coil assembly can adopt an integrated skeleton structure; specifically, referring to Figure 23, the first connector 127, the first skeleton, and the second skeleton are an integrated structure, which can effectively prevent the coil from detaching from the skeleton during the vibration of the voice coil assembly, thereby enhancing the structural stability and integrity of the voice coil assembly itself.

[0216] In some embodiments, the voice coil assembly can adopt a split-frame structure. Specifically, the first frame has an extension portion extending beyond the first coil (e.g., the extension portion of the first frame is located on the long side of the first voice coil 123-1), and the second frame has an extension portion extending beyond the second coil (e.g., the extension portion of the second frame is located on the long side of the second voice coil 123-2). The extension portions of the first frame and the second frame are fixedly connected (e.g., bonded). This allows for the connection of the first voice coil 123-1 and the second voice coil 123-2 to form a frame structure, while also accommodating the size difference between the first voice coil 123-1 and the second voice coil 123-2 to form a clearance channel 123-3. In this case, it can be understood that the voice coil assembly with a frame structure is constructed by omitting the first connector 127, or that the extension portions of the first voice coil 123-1 and the second voice coil 123-2 are connected to form the first connector 127.

[0217] In other embodiments, the first and second frames may not have extended portions. In this case, the first connector 127 may be a patch structure, which is attached and fixed to the same side of the first and second frames, thereby constructing a voice coil assembly that forms a frame structure.

[0218] The above description is merely an embodiment of this application and does not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

An open earphone characterized by The open earphone comprises a sound generating part and an ear hook configured to place the sound generating part in a position close to the ear and not blocking the external auditory canal in a wearing state, the sound generating part comprises a first shell and a sound generating assembly arranged inside the first shell, the first shell has oppositely arranged inner and outer side walls, the inner side wall faces the external auditory canal in a wearing state, and the outer side wall is farther away from the external auditory canal than the inner side wall in a wearing state, the sound generating assembly comprises a loudspeaker, the loudspeaker comprises first and second diaphragms, the first and second diaphragms are oppositely arranged in a vibration direction and synchronously vibrate in the same direction, the first diaphragm is closer to the inner side wall than the second diaphragm, the first diaphragm and the inner side wall are oppositely arranged in the vibration direction with a first acoustic cavity formed therebetween, the second diaphragm and the outer side wall are oppositely arranged in the vibration direction with a second acoustic cavity formed therebetween, the inner side wall is provided with a first sound outlet hole, the first sound outlet hole is in acoustic communication with the loudspeaker through the first acoustic cavity, the outer side wall is provided with a second sound outlet hole, the second sound outlet hole is in acoustic communication with the loudspeaker through the second acoustic cavity, the first sound outlet hole is an array of a plurality of first small holes, the second sound outlet hole is an array of a plurality of second small holes, the open earphone further comprises a microphone assembly, and the open earphone is configured to adjust the output of the loudspeaker based on the ambient noise collected by the microphone assembly to achieve active noise reduction of the ambient noise. An open headphone according to claim 1, characterized in that Each of the first and second diaphragms comprises a main body region and a folded ring region surrounding the main body region, the folded ring regions of the first and second diaphragms are arched away from each other, the main body region of the first diaphragm and the main body region of the second diaphragm have a first spacing distance in the vibration direction, the inner wall surface of the inner side wall and the inner wall surface of the outer side wall have a second spacing distance farthest apart in the vibration direction, the ratio between the first spacing distance and the second spacing distance is not less than 70%, and the loudspeaker further comprises a magnetic circuit assembly arranged between the first and second diaphragms. An open headphone according to claim 1, characterized in that The total opening area of the plurality of second small holes is greater than the total opening area of the plurality of first small holes. An open headphone according to claim 3, characterized in that The number of the plurality of second small holes is greater than the number of the plurality of first small holes. An open headphone according to claim 1, characterized in that The open earphone further comprises first and second sound resistance nets, the first sound resistance net is arranged at the first sound outlet hole and in the first acoustic cavity, the second sound resistance net is arranged at the second sound outlet hole and in the second acoustic cavity, and the sound resistance rate of the first sound resistance net is smaller than that of the second sound resistance net. Open earphone according to claim 4 or 5, characterized in that At least part of the first shell extends into the concha cavity, the ear hook comprises a connecting part connected with the sound generating part, and the microphone assembly comprises a first microphone assembly, which is arranged in the connecting part. Open earphone according to claim 4 or 5, characterized in that At least part of the first shell extends into the concha cavity, the first shell further comprises an upper side wall, which is connected with the inner side wall and the outer side wall and faces the top of the head in the wearing state, and the microphone assembly comprises a second microphone assembly, the upper side wall is provided with an opening, a part of the second microphone assembly is accommodated inside the first shell through the opening, and the other part of the second microphone assembly protrudes outside the first shell, the open earphone further comprises a protrusion arranged on the upper side wall, the part of the second microphone assembly protruding outside the first shell is covered by the protrusion, the protrusion is provided with a second sound collecting hole on the side close to the outer side wall, and the second microphone assembly collects the ambient noise through the second sound collecting hole. An open headphone according to claim 1, characterized in that The open earphone further comprises a limiting assembly, which seals and fixes the loudspeaker in the first shell and forms first and second acoustic cavities, the limiting assembly comprises a first sealing ring and a second sealing ring, the first sealing ring elastically abuts against the inner side wall, and the second sealing ring elastically abuts against the outer side wall, the first sealing ring and the second sealing ring seal and fix the loudspeaker from both sides in the vibration direction. An open headphone according to claim 8, characterized in that The limiting assembly further comprises a first cover and a second cover, the first cover comprises a first transverse side wall and a first longitudinal side wall, the first transverse side wall is between the loudspeaker and the inner side wall, and the second longitudinal side wall surrounds the vibration direction and is fixedly connected with the loudspeaker, the second cover comprises a second transverse side wall and a second longitudinal side wall, the second transverse side wall is between the loudspeaker and the outer side wall, and the second longitudinal side wall surrounds the vibration direction and is fixedly connected with the loudspeaker, one end of the first sealing ring is fixed to the first transverse side wall in the vibration direction, and the other end abuts against the inner side wall; one end of the second sealing ring is fixed to the second transverse side wall in the vibration direction, and the other end abuts against the outer side wall. An open headphone according to claim 9, characterized in that The first longitudinal side wall and the second longitudinal side wall are arranged in the vibration direction and are spaced apart, forming a containing gap around the loudspeaker between the first cover and the second cover, the microphone assembly comprises a second microphone assembly, the second microphone assembly is at least partially embedded in the containing gap, and the second microphone assembly is used to collect the ambient noise. An open headphone according to claim 9, characterized in that The open earphone further comprises a first sound resistance net and a second sound resistance net, the first lateral wall is provided with a first rib structure, the second lateral wall is provided with a second rib structure, the first rib structure is used for supporting and fixing the first sound resistance net in the first acoustic cavity, the second rib structure is used for supporting and fixing the second sound resistance net in the second acoustic cavity, and the number of the first rib structure and the number of the second rib structure are both between 3-5. An open headphone according to claim 9, characterized in that Each of the first diaphragm and the second diaphragm comprises a main body region and a folded ring region surrounding the main body region, the folded ring region of the first diaphragm and the folded ring region of the second diaphragm are arched in a direction away from each other, each of the first lateral wall and the second lateral wall has a center part and an arc part surrounding the center part, in the vibration direction, the center part of the first lateral wall faces the main body region of the first diaphragm, the arc part of the first lateral wall faces the folded ring region of the first diaphragm, the center part of the second lateral wall faces the main body region of the second diaphragm, and the arc part of the second lateral wall faces the folded ring region of the second diaphragm. An open headphone according to claim 12, characterized in that The connection between the arc part of the first lateral wall and the first longitudinal wall is provided with a first annular table, the connection between the arc part of the second lateral wall and the second longitudinal wall is provided with a second annular table, the first annular table and the second annular table respectively abut the two sides of the loudspeaker along the vibration direction, and sealing glue is arranged in the abutting area. Open earphone according to any of claims 9-13, characterized in that The limiting assembly is provided with a first sound guide hole communicating the space on both sides of the first lateral wall and a second sound guide hole communicating the space on both sides of the second lateral wall; on a reference plane perpendicular to the vibration direction, the projection of the first sound guide hole and the projection of the first diaphragm have a first overlapping area, the area ratio of the first overlapping area to the projection of the first sound guide hole is not less than 80%, the projection of the first sound hole and the projection of the first sound guide hole have a second overlapping area, the area ratio of the second overlapping area to the projection of the first sound hole is not less than 80%, the projection of the second sound guide hole and the projection of the second diaphragm have a third overlapping area, the area ratio of the third overlapping area to the projection of the second sound guide hole is not less than 80%, the projection of the second sound hole and the projection of the second sound guide hole have a fourth overlapping area, and the area ratio of the fourth overlapping area to the projection of the second sound hole is not less than 80%. An open headphone according to claim 1, characterized in that The loudspeaker further comprises a magnetic circuit assembly and a voice coil assembly, the magnetic circuit assembly is arranged between the first diaphragm and the second diaphragm, the voice coil assembly comprises a first voice coil and a second voice coil arranged and connected in the vibration direction of the first diaphragm and the second diaphragm, the first voice coil and the second voice coil are respectively arranged in the magnetic gap of the magnetic circuit assembly, one end of the first voice coil away from the second voice coil is connected to the first diaphragm, and one end of the second voice coil away from the first voice coil is connected to the second diaphragm; the magnetic circuit assembly cooperates with the voice coil assembly to drive the first diaphragm and the second diaphragm to vibrate synchronously and in the same direction. An open headphone according to claim 1, characterized in that The first shell is an integral metal piece, the wall thickness of the inner side wall and the outer side wall is between 0.2mm-1mm, the aperture of the plurality of first small holes is not less than 0.2mm, the interval distance between adjacent first small holes is between 0.2mm-4mm, the aperture of the plurality of second small holes is not less than 0.2mm, and the interval distance between adjacent second small holes is between 0.2mm-4mm. An open headphone according to claim 1, characterized in that The ear hook comprises an adapter part connected to the sound generating part, the first shell is an integral metal piece, the first shell is provided with a first opening at one end close to the adapter part, the sound generating assembly is inserted into the first shell through the first opening, and the adapter part is connected to the first shell through the first opening. An open headphone according to claim 17, characterized in that The first shell further comprises an upper side wall and a terminal wall, the upper side wall is arranged towards the top of the head in the wearing state and connected to the inner side wall and the outer side wall, and the terminal wall is located at one end of the first shell away from the adapter part and connected to the inner side wall, the outer side wall and the upper side wall, wherein the open earphone further comprises a protrusion arranged on the upper side wall and / or the terminal wall, the upper side wall and / or the terminal wall are provided with a second opening, a part of the protrusion is embedded in the second opening, another part of the protrusion protrudes outside the first shell, the hardness of the protrusion is less than that of the first shell, at least part of the structure of the first shell extends into the concha cavity, and the protrusion contacts the wall of the concha cavity. An open headphone according to claim 1, characterized in that At least part of the structure of the first shell extends into the concha cavity, and the first shell further comprises a terminal wall, the terminal wall is located at one end of the first shell away from the ear hook and connected to the inner side wall and the outer side wall, and the first sound outlet is arranged close to the terminal wall. An open earphone according to claim 19, characterized in that The inner side wall is provided with a sound adjusting hole, the sound adjusting hole is arranged to be farther away from the position of the terminal wall than the first sound outlet, and the interval distance between the sound adjusting hole and the nearest first small hole is not less than 5 times the interval distance between adjacent first small holes.

Images