Audio output device

Abstract

The present application discloses an acoustic output device, which includes an acoustic driver including a diaphragm and a magnetic circuit structure, wherein the side of the diaphragm facing away from the magnetic circuit structure is the front side of the acoustic driver, and the side of the magnetic circuit structure facing away from the diaphragm is the back side of the acoustic driver, and wherein the acoustic driver radiates sound to the outside from the front side and back side, respectively, due to vibration of the diaphragm, and a housing structure configured to mount the acoustic driver, wherein one of the front and back sides of the acoustic driver and the housing structure form a cavity, and sound is radiated into the cavity from one side of the acoustic driver that forms the cavity, and sound is radiated to the outside of the acoustic output device from the other side of the acoustic driver.

Description

Technical Field

[0001] [Priority Information] This application claims the priority of Application No. 201910888762.2 filed on September 19, 2019, and Application No. 201910888067.6 filed on September 19, 2019, and all of its contents are incorporated herein by reference.

[0002] This application relates to the field of acoustics, and particularly to an acoustic output device.

Background Art

[0003] An acoustic output device that does not block both ears is a portable sound output device that realizes acoustic conduction within a specific range. Compared with conventional canal-type earphones and headphones, the acoustic output device that does not block both ears has the characteristics of not blocking or covering the ear canals, enabling the user to obtain sound information in the external environment while listening to music, and improving safety and comfort. Due to the use of an open structure, the sound leakage of the acoustic output device that does not block both ears is generally more serious than that of conventional earphones. Currently, the common method in the industry is to place a speaker in the acoustic cavity, open holes on the front and back of the acoustic cavity respectively to construct a dipole, generate a specific sound field with a certain directivity, and adjust the sound pressure distribution to reduce sound leakage in the far field. Although this method can achieve the effect of reducing sound leakage to a certain extent, there are still certain limitations. For example, the acoustic output device has low frequency responses in the medium and high frequencies and low frequencies.

Summary of the Invention

Problems to be Solved by the Invention

[0004] Therefore, it is desirable to provide an acoustic output device that can achieve the effect of reducing sound leakage while increasing the user's listening volume.

Means for Solving the Problems

[0005] An acoustic output device according to an embodiment of the present application is an acoustic driver including a diaphragm and a magnetic circuit structure, wherein a side of the diaphragm facing away from the magnetic circuit structure is the front of the acoustic driver, a side of the magnetic circuit structure facing away from the diaphragm is the back of the acoustic driver, and the acoustic driver radiates sound to the outside from its front and back respectively due to the vibration of the diaphragm. The acoustic output device further includes a housing structure configured to mount the acoustic driver, and a cavity is formed between one of the front and back of the acoustic driver and the housing structure. The acoustic driver radiates sound into the cavity from the side forming the cavity, and radiates sound to the outside of the acoustic output device from the other side of the acoustic driver.

[0006] In some embodiments, the housing structure includes at least one sound guiding hole that is acoustically coupled to the cavity and guides the sound radiated by the acoustic driver into the cavity to the outside of the acoustic output device.

[0007] In some embodiments, the at least one sound guiding hole is close to the central position on the side of the housing structure facing the acoustic driver.

[0008] In some embodiments, the cross-sectional area of the at least one sound guiding hole is 0.25 mm 2 or more.

[0009] In some embodiments, an acoustic attenuation structure is provided in the at least one sound guiding hole.

[0010] In some embodiments, the magnetic circuit structure includes a magnetic conduction plate provided opposite to the diaphragm, and the magnetic conduction plate includes at least one sound guiding hole that guides the sound generated by the vibration of the diaphragm from the back of the acoustic driver.

[0011] In some embodiments, the front surface of the acoustic driver and the housing structure form the cavity, and the at least one sound guiding hole guides the sound generated by the vibration of the diaphragm from the back surface of the acoustic driver to the outside of the acoustic output device.

[0012] In some embodiments, a sound guiding tube is provided in the at least one sound guiding hole along the direction away from the diaphragm, and the sound guiding tube guides the sound radiated from the at least one sound guiding hole to the outside of the acoustic output device.

[0013] In some embodiments, the at least one sound guiding hole includes a first hole portion and a second hole portion provided in order from the inside, the first hole portion and the second hole portion penetrate, and the diameter of the second hole portion is larger than the diameter of the first hole portion.

[0014] In some embodiments, the height of the cavity along the vibration direction of the diaphragm is 3 mm or less.

[0015] In some embodiments, the shape of the diaphragm is planar or substantially planar.

[0016] In some embodiments, the diaphragm is fixed to the acoustic driver by an edge that is recessed in the direction away from the cavity.

[0017] In some embodiments, the back surface of the acoustic driver and the housing structure form the cavity, and a protection structure provided for the diaphragm is further provided on the front surface of the acoustic driver.

[0018] In some embodiments, the protection structure is configured to separate the diaphragm from the outside and allow the sound emitted from the diaphragm to propagate to the outside.

[0019] In some embodiments, the protection structure includes a filter structure.

[0020] In some embodiments, the protection structure includes a plate structure having at least one sound guiding hole.

[0021] In some embodiments, the cavity guides sound to the outside of the acoustic output device through a first sound guiding hole, and on a surface different from the surface forming the cavity of the acoustic driver, guides sound to the outside of the acoustic output device through a second sound guiding hole, and the first sound guiding hole and the second sound guiding hole have different acoustic impedances.

[0022] In some embodiments, on one of the front or back surfaces of the acoustic driver, the surface with a larger amplitude value of the high-frequency response has an acoustic path to the ear that is closer than the other surface.

[0023] In some embodiments, on one of the front or back surfaces of the acoustic driver, the surface with a larger amplitude value of the high-frequency response in the high-frequency band faces the ear canal.

[0024] An acoustic output device according to an embodiment of the present application is an acoustic driver including a diaphragm and a magnetic circuit structure, wherein a side of the diaphragm facing away from the magnetic circuit structure is the front of the acoustic driver, a side of the magnetic circuit structure facing away from the diaphragm is the back of the acoustic driver, and the acoustic driver radiates sound to the outside from its front and back respectively due to the vibration of the diaphragm.

[0025] In some embodiments, the magnetic circuit structure includes a magnetic conduction plate provided opposite to the diaphragm, and the magnetic conduction plate includes at least one sound guiding hole for guiding sound generated by the vibration of the diaphragm from the back of the acoustic driver.

[0026] In some embodiments, a protection structure provided for the diaphragm is further provided on the front of the acoustic driver, and the protection structure is connected to the magnetic circuit structure.

[0027] The present application will be further described by exemplary embodiments, and these exemplary embodiments will be described in detail with reference to the drawings. These embodiments are not restrictive, and in these embodiments, the same numbers indicate the same structures.

Brief Description of the Drawings

[0028]

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Embodiments for Carrying Out the Invention

[0029] To more clearly explain the technical means of the embodiments of the present application, the drawings necessary for the description of the embodiments will be briefly described below. Obviously, the drawings described below are only some examples or embodiments of the present application, and for those skilled in the art, without creative effort, the present application can be further applied to other similar situations based on these drawings. Unless otherwise clear in the language environment or otherwise stated, the same numbers in the figures represent the same structure or operation.

[0030] It should be understood that the "system", "device", "unit" and / or "module" used in this specification are ways to distinguish different assemblies, elements, members, parts or assemblies at different levels. However, if other words can achieve the same purpose, the above words can be replaced by other expressions.

[0031] As shown in the present application and the claims, unless otherwise clearly indicated in the context, words such as "a", "one", "a kind" and / or "the" do not particularly refer to the singular, but can mean plural. Generally, the terms "include" and "contain" only indicate that they include the steps and elements that have been clearly identified, but these steps and elements do not constitute an exclusive list, and the method or device may also include other steps and elements.

[0032] In the present application, flowcharts are used to describe the operations performed by the system according to the embodiments of the present application. It should be understood that the previous or subsequent operations are not necessarily executed exactly in accordance with the order. On the contrary, each step may be processed in the reverse order or simultaneously. At the same time, other operations may be added to these processes, or the operations of one or more steps may be removed from these processes.

[0033] FIG. 1 is a schematic structural diagram illustrating an example of an acoustic output device according to some embodiments of the present application. As shown in FIG. 1, the acoustic output device 100 may include a housing structure 110 with a hollow interior and an acoustic driver 120 provided within the housing structure 110. The acoustic driver 120 may include a diaphragm 121 and a magnetic circuit structure 1220. The acoustic driver 120 may further include a voice coil (not shown). The voice coil may be fixed to the side of the diaphragm 121 facing the magnetic circuit structure 1220 and may be located within the magnetic field formed by the magnetic circuit structure 1220. After being energized, the voice coil vibrates under the action of the magnetic field and drives the diaphragm 121 to vibrate, thereby generating sound. For ease of explanation, the side of the diaphragm 121 facing away from the magnetic circuit structure 1220 (i.e., the right side of the diaphragm 121 in FIG. 1) can be considered the front of the acoustic driver 120, and the side of the magnetic circuit structure 1220 facing away from the diaphragm 121 (i.e., the left side of the magnetic circuit structure 1220 in FIG. 1) can be considered the back of the acoustic driver 120. Due to the vibration of the diaphragm 121, the acoustic driver 120 may radiate sound to the outside from its front and back surfaces, respectively. As shown in FIG. 1, the front of the acoustic driver 120 or the diaphragm 121 and the housing structure 110 form a first cavity 111, and the back of the acoustic driver 120 and the housing structure 110 form a second cavity 112. Sound is radiated from the front of the acoustic driver 120 into the first cavity 111 and from the back of the acoustic driver 120 into the second cavity 112. In some embodiments, the housing structure 110 further includes a first sound guiding hole 113 and a second sound guiding hole 114, where the first sound guiding hole 113 communicates with the first cavity 111 and the second sound guiding hole 113 communicates with the second cavity 112. The sound generated on the front of the acoustic driver 120 propagates to the outside through the first sound guiding hole 113, and the sound generated on the back of the acoustic driver 120 propagates to the outside through the second sound guiding hole 114. In some embodiments, the magnetic circuit structure 1220 may include a magnetic conduction plate 1221 provided opposite to the diaphragm.At least one sound induction hole 1222 (also called a pressure relief hole) is formed in the magnetic conduction plate 1221 to guide the sound generated by the vibration of the diaphragm 121 from the back surface of the acoustic driver 120 and transmit it to the outside through the second cavity 112. The acoustic output device 100 forms a two-point sound source (or multi-sound source) similar to a dipole structure by the acoustic radiation of the first sound induction hole 113 and the second sound induction hole 114, and generates a specific sound field with a certain directivity. Note that the acoustic output device in the embodiments of this specification is not limited to the application of earphones and may be applied to other sound output devices (for example, hearing aids, speakers, etc.).

[0034] Figure 2 is a frequency response graph of the first sound induction hole and the second sound induction hole in Figure 1. As shown in Figure 2, due to the first cavity 111 and the second cavity 112 provided in the acoustic output device 100, the sound radiated from the first sound induction hole 113 (sound induction hole 1 in Figure 2) and the second sound induction hole 114 (sound induction hole 2 in Figure 2) by the acoustic output device 100 generates one resonance peak at a medium frequency or a medium-high frequency (for example, 2000 Hz to 4000 Hz). After the resonance peak, a difference may occur in the degree of attenuation of the frequency response at the first sound induction hole 113 and the second sound induction hole 114 (the frequency response at the second sound induction hole 114 attenuates faster), so that the dipole-like structure formed by the acoustic output device 100 has a poor frequency response at high frequencies (for example, radiates sounds with a large amplitude value difference from two sound induction holes), and it becomes impossible to effectively suppress sound leakage in the far field of the acoustic output device 100. Also, as can be seen from the curve in Figure 2, the first sound induction hole 113 and the second sound induction hole 114 have a very small difference in amplitude value at low frequencies (for example, less than 500 Hz), and the sounds radiated from the first sound induction hole 113 and the second sound induction hole 114 have opposite or almost opposite phases. Therefore, the low-frequency sound generated at the listening position (for example, the human auricle) of the acoustic output device 100 is attenuated by the inverse-phase cancellation of the sound, resulting in a poor low-frequency response at the listening position.

[0035] In order to further improve the sound output effect of the audio output device 100, this specification describes another type or multiple types of audio output devices including an acoustic driver. When the user wears the above audio output device, the above audio output device is located at least on one side of the user's head and is close to the user's ear but does not block the user's ear. The audio output device may be worn on the user's head (for example, non-canal open-type earphones worn in the form of glasses, headbands or other structural methods), may be worn on other parts of the user's body (for example, the user's neck / shoulder area), or may be worn near the user's ear in other ways (for example, the way the user holds it by hand). The above audio output device may include an acoustic driver for generating sound and a housing structure on which the above acoustic driver is mounted. In some embodiments, the above housing structure forms a cavity with only one of the front and back surfaces of the above acoustic driver. The front or back surface of the above acoustic driver may be located in the above cavity or acoustically coupled to the cavity. The surface (if any) of the above acoustic driver that forms the above cavity radiates sound into the above cavity, and the sound may propagate to the outside through the sound guiding holes of the housing structure. Sound may also be directly radiated from the other surface of the above acoustic driver to the outside of the above audio output device. In some embodiments, neither the front nor the back surface of the acoustic driver forms a cavity with the housing structure. Sound may be directly radiated to the outside from the front and back surfaces of the acoustic driver without passing through the cavity. As can be seen from the above, the above method can effectively reduce the number of cavities formed on both sides of the above acoustic driver by the above housing structure. In such a situation, while the size of the above audio output device can be effectively reduced, it is possible to avoid increasing the influence of the cavity on the frequency characteristics of the output sound of the above audio output device.

[0036] In some embodiments, the housing structure of the acoustic output device may partition the front and back of the acoustic driver as a baffle. On the other hand, the baffle can increase the acoustic path difference (i.e., the acoustic path difference between the front sound and the back sound of the acoustic driver reaching the user's ear canal) between the front and back of the acoustic driver, thereby weakening the effect of sound cancellation. Further, by increasing the volume of the sound (also called near-field sound) heard by the user's ear, a preferable auditory experience is provided to the user. On the other hand, the influence of the baffle on propagating sound (also called far-field sound) from the front and back of the acoustic driver to the environment is small. The sound radiated from the front of the acoustic driver and the sound radiated from the back of the acoustic driver cancel each other out in the far field, suppressing the sound leakage of the acoustic output device to a certain extent and at the same time preventing the sound generated by the acoustic output device from being heard by others near the user.

[0037] For the sole purpose of facilitating description and explanation, when the size of the sound guiding hole on the acoustic output device is small, each sound guiding hole may be regarded as approximately a single point sound source. The sound field sound pressure p generated by the single point sound source satisfies the following formula (1).

[0038]

Equation

[0039] Here, ω is the angular frequency, ρ 0 is the air density, r is the distance between the target point and the sound source, Q 0 is the sound source volume velocity, k is the wave number, and the magnitude of the sound field sound pressure of the point sound source is inversely proportional to the distance to the point sound source.

[0040] As described above, by providing two sound guiding holes in the acoustic output device to form a two-point sound source, the sound radiated by the sound output device into the surrounding environment (i.e., sound leakage in the far field) can be reduced. In some embodiments, the two sound guiding holes, that is, the sound output from the two-point sound source, have a certain phase difference. When the position, phase difference, etc. between the two-point sound sources meet certain conditions, the acoustic output device can exhibit different sound effects in the near field and the far field. For example, when the phases of the point sound sources corresponding to the two sound guiding holes are opposite, that is, the absolute value of the phase difference between the two point sound sources is 180°, based on the principle of sound wave inverse-phase cancellation, the reduction of sound leakage in the far field can be realized.

[0041] As shown in FIG. 3, the sound field sound pressure p generated by the two-point sound source satisfies the following formula (2).

[0042]

Equation

[0043] Here, A 1 , A 2 are the intensities of the two point sound sources respectively, φ 1 , φ 2 are the phases of the point sound sources, d is the distance between the two point sound sources, and r 1 and r 2 satisfy formula (3).

[0044]

Equation

[0045] Here, r is the distance between an arbitrary target point in space and the center position of the two-point sound source, and θ represents the included angle between the connection line between the target point and the center of the two-point sound source and the straight line where the two-point sound source is located.

[0046] As can be seen from formula (3), the magnitude of the sound pressure p of the target point in the sound field is related to the sound source intensity, interval d, phase, and distance from the sound source of each point.

[0047] FIG. 4 is a sound leakage diagram in the far field of a single-point sound source and a two-point sound source according to some embodiments of the present application. As shown in FIG. 4, in the far field, when the interval between the two-point sound sources is constant, within a certain frequency range (for example, 100 Hz to 8000 Hz), the sound leakage volume generated by the two-point sound sources is smaller than the sound leakage volume of the single-point sound source. That is, when within a certain frequency range, the sound reduction ability of the above two-point sound sources is higher than the sound reduction ability of the single-point sound source. Note that the sound source in this embodiment takes a point sound source as an example and does not limit the type of the sound source. The sound source in other embodiments may be a surface sound source.

[0048] FIG. 5 is a schematic structural diagram of an acoustic output device according to some embodiments of the present application. As shown in FIG. 5, the acoustic output device 500 may include a housing structure 510 and an acoustic driver 520 connected to the housing structure 510.

[0049] In some embodiments, the housing structure 510 can be used to be worn on the user's body and can mount one or more acoustic drivers 520. In some embodiments, the housing structure 510 may be a sealed housing structure with a hollow interior, and one or more acoustic drivers 520 are fixedly connected to the housing structure 510.

[0050] In some embodiments, the acoustic output device 500 may be worn on a user's body (e.g., the head, neck, or upper body of a human body) by the housing structure 510. At the same time, the housing structure 510 and the acoustic driver 520 are close to the ear canal but do not block the ear canal, so that the user's ear remains in an open state, and the user can hear the sound output from the acoustic output device 500 and at the same time obtain the sound of the external environment. For example, the acoustic output device 500 may be provided around or partially around the peripheral side of the user's ear. In some embodiments, the acoustic output device 500 may be combined with products such as glasses, headphones, head-mounted display devices, AR / VR helmets, etc. In such a situation, the housing structure 510 may be fixed near the user's ear in a suspended or clamped manner. In some alternative embodiments, a hook may be provided on the housing structure 510, and by adapting the shape of the hook to the shape of the auricle, the acoustic output device 500 may be worn independently on the user's ear by the hook. The acoustic output device 500 worn and used independently may be communicatively connected to a signal source (e.g., a computer, a mobile phone, or other mobile device) in a wired or wireless (e.g., Bluetooth (registered trademark)) manner. For example, the acoustic output devices 500 on both the left and right ears may be directly communicatively connected to the signal source in a wireless manner. Also, for example, the acoustic output devices 500 on both the left and right ears may include a first output device and a second output device. Here, the first output device may be communicatively connected to the signal source, the second output device may be wirelessly connected to the first output device in a wireless manner, and synchronization of audio playback is realized between the first output device and the second output device by one or more synchronization signals. The wireless connection method includes, but is not limited to, Bluetooth (registered trademark), local area network, wide area network, wireless personal area network, near-field wireless communication, etc. or any combination thereof.

[0051] In some embodiments, the housing structure 510 may be a housing structure having a shape adapted to the human ear. For example, by having an annular shape, an elliptical shape, a polygonal shape (regular or irregular), a U-shape, a V-shape, or a semi-circular shape, the housing structure 510 may be directly hung on the user's ear. In some embodiments, the housing structure 510 may further include one or more fixing structures. Since the fixing structure may include an earhook, a head beam, or an elastic band, the acoustic output device 500 can be better fixed by the user and prevented from falling during the user's use. By way of merely illustrative explanation, for example, the elastic band may be a headband configured to be worn around the head region. Also, for example, the elastic band may be a neckband configured to be worn around the neck / shoulder region. In some embodiments, the elastic band may be a continuous strip, and may be elastically stretched and worn on the user's head, and at the same time, by applying pressure to the user's head, the acoustic output device 500 can be firmly fixed at a specific position on the user's head. In some embodiments, the elastic band may be a discontinuous strip. For example, the elastic band may include a rigid portion and a flexible portion. Here, the rigid portion may be manufactured from a rigid material (for example, plastic or metal) and may be fixed to the housing structure 510 of the acoustic output device 500 by a method of physical connection (for example, locking, screw connection, etc.). The flexible portion may be manufactured from an elastic material (for example, fabric, composite material, or / and chloroprene rubber).

[0052] The acoustic driver 520 is an element that can receive an electrical signal and convert the electrical signal into an acoustic signal for output. In some embodiments, when distinguished according to frequency, the types of the acoustic driver 120 may include a low-frequency (e.g., 3 kHz or less) acoustic driver, a mid-high frequency (e.g., 3 kHz to 7 kHz) acoustic driver, or a high-frequency (e.g., greater than 7 kHz) acoustic driver, or any combination thereof. Of course, the low frequency, high frequency, etc. mentioned here only indicate the approximate range of the frequency, and different application scenarios may have different classification methods. For example, one crossover wavelength may be determined, the low frequency indicates the frequency range below the crossover wavelength, and the high frequency indicates the frequency above the crossover wavelength. The crossover wavelength may be any value within the audible range of the human ear, such as 500 Hz, 600 Hz, 700 Hz, 800 Hz, 1000 Hz, etc. In some embodiments, when distinguished according to principle, the acoustic driver 520 may further include, but is not limited to, drivers such as moving coil type, moving iron type, piezoelectric type, electrostatic type, magnetostrictive type, etc.

[0053] The acoustic driver 520 may include a diaphragm 521 and a magnetic circuit structure 522. The diaphragm 521 and the magnetic circuit structure 522 are provided in sequence along the vibration direction of the diaphragm 521. In some embodiments, the diaphragm 521 may be attached to a frame (not shown), and then the frame may be fixed to the magnetic circuit structure 522. Alternatively, the diaphragm 521 may be directly fixedly connected to the side wall of the magnetic circuit structure 522. The side of the diaphragm 521 facing away from the magnetic circuit structure 522 is the front of the acoustic driver 520, the side of the magnetic circuit structure 522 facing away from the diaphragm 521 is the back of the acoustic driver 520, and the acoustic driver 520 radiates sound to the outside from its front and back respectively due to the vibration of the diaphragm 521.

[0054] The front surface of the acoustic driver 520 and the housing structure 510 form a cavity 511. Sound is radiated from the front surface of the acoustic driver 520 into the cavity 511, and sound is radiated from the back surface of the acoustic driver 520 to the outside of the acoustic output device 500. In some embodiments, one or more sound guiding holes 512 are provided in the housing structure 510. The sound guiding holes 512 are acoustically coupled to the cavity 511 and guide the sound radiated by the acoustic driver 520 into the cavity 511 to the outside of the acoustic output device 500. In some embodiments, the magnetic circuit structure 522 may include a magnetic conduction plate 523 provided opposite to the diaphragm 521. One or more sound guiding holes 524 (also called pressure relief holes) are provided in the magnetic conduction plate 523. The sound guiding holes 524 guide the sound generated by the vibration of the diaphragm 521 from the back surface of the acoustic driver 520 to the outside of the acoustic output device 500. Since the sound guiding holes 512 and the sound guiding holes 524 are located on both sides of the diaphragm 521 respectively, the sounds guided from the sound guiding holes 512 and the sound guiding holes 524 can be considered to have opposite or substantially opposite phases. Therefore, the sound guiding holes 512 and the sound guiding holes 524 may form a set of two-point sound sources as shown in FIG. 3.

[0055] In some embodiments, the diaphragm 521 may be fitted into the side wall of the housing structure 510. For example, mounting holes (not shown) may be formed in the side wall of the housing structure 510, and the end of the diaphragm 521 may be fixed to the mounting holes, thereby realizing the acoustic coupling between the front surface of the acoustic driver 520 or the diaphragm 521 and the cavity 511 of the housing structure 510. In some embodiments, the side of the acoustic driver 520 having the diaphragm 521 may be housed inside the housing structure 510, and the periphery of the magnetic circuit structure 522 in the acoustic driver 520 may be connected to the side wall of the housing structure 510. As a result, the diaphragm 521 is located inside the housing structure 510 and forms the housing structure 510 and the cavity 511.

[0056] FIG. 6 is a frequency response graph of the front and back surfaces of the acoustic output device 500 shown in FIG. 5. As shown in FIG. 6, since the sound generated on the back surface of the acoustic driver 520 (the curve corresponding to "back cavity" in FIG. 6) is directly propagated to the outside through the sound guiding hole 524, the process in which the sound generated on the front surface of the acoustic driver 520 is propagated to the outside from the sound guiding hole 512 after passing through the cavity 511 (the curve corresponding to "sound guiding hole 1" in FIG. 6) is different. In this way, the acoustic output device 500 can make the resonance peak of the sound generated in the sound guiding hole 524 at a higher frequency position (for example, 7 kHz to 8 kHz). In such a situation, the frequency response curve before the resonance peak can improve the sound output effect in the case of high frequencies of the acoustic output device 500 by maintaining a flatter distribution within a wider frequency range. Referring to FIGS. 1, 2, 5, and 6, FIG. 2 is a frequency response curve of the acoustic output device 100 shown in FIG. 1, and FIG. 6 is a frequency response curve of the acoustic output device 500 shown in FIG. 5. The acoustic output device 500 shown in FIG. 5 has one less cavity (for example, the second cavity 112) than the acoustic output device 100 shown in FIG. 1. The sound wave generated by the diaphragm 521 of the acoustic output device 500 has no coupling with the cavity on the back surface compared to the sound wave generated by the diaphragm 121 of the acoustic output device 100. Therefore, the frequency response curves at the sound guiding hole 524 and the sound guiding hole 512 in the acoustic output device 500 have a higher frequency resonance peak at a higher frequency position (for example, 7 kHz to 8 kHz). Also, the frequency responses at the sound guiding hole 524 and the sound guiding hole 512 are more consistent at high frequencies. That is, in the case of high frequencies, the phases of the sound guiding hole 524 and the sound guiding hole 512 are opposite, and the corresponding amplitude values are more consistent. In the far field, the sound waves on the front and back surfaces of the acoustic driver 520 may cancel each other out. Referring to the above description, in the case of high frequencies, the effect of reducing sound leakage of the acoustic output device 500 compared to the acoustic output device 100 is better. Furthermore, the frequency response curve before the resonance peak can maintain a flatter distribution within a wider frequency range, resulting in better listening sound quality of the acoustic output device 500 in the case of high frequencies.Further, based on the structure of the acoustic output device 500, the frequency responses at the sound guiding holes 512 and 524 of the acoustic driver 520 are very close within the mid-high frequency range (e.g., 3 kHz to 7 kHz). That is, the frequency response corresponding to the front of the acoustic driver 520 and the frequency response corresponding to the back are very close within the mid-high frequency range. Therefore, sound waves with opposite or almost opposite phases can be radiated from the front and back of the acoustic driver 520. In the far field, by canceling out each other's sound waves from the front and back of the acoustic driver 520, the sound leakage at mid-high frequencies of the acoustic output device 500 can be significantly reduced.

[0057] In the low frequency band (e.g., 3 kHz or less), the amplitude value of the frequency response at the sound guiding hole 512 (the curve corresponding to "Sound Guiding Hole 1" in FIG. 6) is larger than the amplitude value of the frequency response at the sound guiding hole 524 (the curve corresponding to "Back Cavity" in FIG. 6). Therefore, in the near field, the amplitude value of the sound radiated from the sound guiding hole 512 to the user's ear is larger than the amplitude value of the sound radiated from the sound guiding hole 524 to the user's ear. Due to the weak effect of inverse-phase cancellation of sound waves, the listening volume at low frequencies at the listening position (i.e., the user's ear) can be improved. Preferably, when the sound outlet hole 512 faces or is closer to the ear, the difference between the amplitude value of the sound radiated from the sound guiding hole 512 to the user's ear and the amplitude value of the sound radiated from the sound guiding hole 524 to the user's ear further increases, and the effect of inverse-phase cancellation of sound waves becomes weaker. Therefore, the listening volume at low frequencies at the listening position becomes larger. In the far field, since the human ear is not sensitive to low frequencies, although the amplitude values of the sounds radiated from the sound guiding hole 512 and the sound guiding hole 524 to the outside are different, the sound leakage perceived by the human ear does not increase significantly.

[0058] In the high-frequency band (higher than 7 kHz), the amplitude value of the frequency response at the sound induction hole 512 is significantly larger than the amplitude of the frequency response at the sound induction hole 524. Since the acoustic output device 500 has a strong directivity at high frequencies, it is possible to achieve the effect of increasing the near-field listening volume and reducing the far-field sound leakage volume by utilizing the directivity of high-frequency sound waves. Due to the fact that the wavelength of high-frequency sound waves is shorter than those of intermediate-frequency and low-frequency sound waves, high-frequency sound waves have a strong directivity. The directivity of high-frequency sound waves is strong, that is, the volume in the direction it points is large, and the volume in other directions is small. For example, when the user wears the acoustic output device 500, the sound induction hole 512 can be close to the external auditory canal, and the sound induction hole 524 is away from the ear canal. In the case of high frequencies, since the sound waves at the sound induction hole 524 do not point to the ear canal, by suppressing the high-frequency sound waves radiated from the sound induction hole 524, the high-frequency response at the sound induction hole 524 can be made as low as possible. When all the high-frequency sound waves generated at the sound induction hole 512 point to the ear, the high-frequency sound heard by the ear is large, and the sound in other directions is small (that is, the sound leakage volume of the sound induction hole 524 is small). Therefore, since the amplitude value of the frequency response at the sound induction hole 512 is significantly larger than the amplitude value of the frequency response at the sound induction hole 524, it is possible to achieve the effect of increasing the near-field listening volume and reducing the far-field sound leakage volume of the acoustic output device 500. Note that the frequency response at the sound induction hole 512 in the above embodiment may be regarded as the frequency response corresponding to the front of the acoustic driver 520, and the frequency response at the sound induction hole 524 may be regarded as the frequency response corresponding to the back of the acoustic driver 520.

[0059] FIG. 7 is a schematic structural diagram of an acoustic output device according to some embodiments of the present application. As shown in FIG. 7, in some embodiments, the sound guiding hole 524 may include a first hole portion 5241 and a second hole portion 5242 provided in order from the inside to the outside. The first hole portion 5241 and the second hole portion 5242 penetrate through, and the size of the second hole portion 5242 is different from the size of the first hole portion 5221. For example, when both the first hole portion 5241 and the second hole portion 5242 are circular, the diameter of the second hole portion 5242 may be equal to or greater than the diameter of the first hole portion 5241. Note that the shapes of the first hole portion 5241 and the second hole portion 5242 of the sound guiding hole 524 described above are not limited to circular, and may be semi-circular, 1 / 4 circular, elliptical, semi-elliptical, polygonal, etc., and will not be further limited here.

[0060] As can be seen from the above, by providing the first hole portion 5241 and the second hole portion 5242 at the position of the sound guiding hole 524, the frequency response of radiating sound from the back surface of the acoustic driver 520 to the outside (that is, radiating sound from the sound guiding hole 524 to the outside) can be adjusted. In some alternative embodiments, the sound guiding hole 524 may be a hole portion whose cross-sectional area gradually increases or gradually decreases from the inside to the outside. In some embodiments, a plurality of sound guiding holes 524 may be formed on the back surface of the acoustic driver 520. Different sound guiding holes 524 may have the same or different structural settings.

[0061] FIG. 8 is a frequency response graph of the front and back surfaces of the acoustic output device shown in FIG. 7. As shown in FIG. 8, in the mid- to high-frequency band (for example, 5 kHz to 6 kHz), since the frequency responses at the sound guiding holes 512 (the curve corresponding to "Sound guiding hole 1" in FIG. 8) and at the sound guiding holes 524 (the curve corresponding to "Back cavity" in FIG. 8) are very close, the sound guiding holes 512 and the sound guiding holes 524 may be regarded as two-point sound sources having the same amplitude value. Also, since the sound waves emitted from the sound guiding holes 524 and the sound waves emitted from the sound guiding holes 524 are out of phase, the sound leakage in the far field of the mid- to high-frequency band of the acoustic output device can be significantly reduced. In the high-frequency band (for example, 7 kHz to 9 kHz), since the amplitude value of the frequency response at the sound guiding holes 512 is larger than the amplitude value of the frequency response at the sound guiding holes 524, the effect of increasing the near-field listening volume and reducing the far-field sound leakage volume by utilizing the directivity of the sound waves in the high-frequency band can be achieved.

[0062] In some embodiments, by adjusting the structure, size, shape, position, etc. of the sound guiding holes 524 and / or the sound guiding holes 512 to adjust the frequency responses at the sound guiding holes 512 and the sound guiding holes 524, the acoustic output effect of the acoustic output device can be improved. When the size or position of the sound guiding holes 512 and the sound guiding holes 524 changes, the change situation of the frequency responses at the sound guiding holes 512 and the sound guiding holes 524 may be referred to FIG. 12, FIG. 17 and FIG. 18 of the present application and their related descriptions.

[0063] In some embodiments, as shown in FIG. 9, a sound guiding tube 525 may be further provided in the sound guiding hole 524. The sound guiding tube 525 may be provided along a direction away from the diaphragm, that is, it may extend from the sound guiding hole 524 to the outside of the acoustic output device. The sound guiding tube 525 may guide the sound radiated from the sound guiding hole 524 to the outside of the acoustic output device. In some embodiments, the sound guiding tube 525 in the sound guiding hole 524 may adjust the frequency response of radiating sound from the back surface of the acoustic driver 520 to the outside (that is, radiating sound from the sound guiding hole 524 to the outside). For example, the frequency response corresponding to the sound guiding tube 525 may be adjusted by adjusting the tube diameter or cross-sectional area of the sound guiding tube. In some embodiments, the sound guiding tube 525 may be a straight tube or a tube structure whose cross-sectional area gradually increases along a direction away from the diaphragm 521.

[0064] FIG. 10 is a frequency response graph when the volume of the cavity of the acoustic output device shown in FIG. 9 is different. In some embodiments, by adjusting the volume of the cavity 511, the acoustic output effect in the high-frequency range of the acoustic output device can be improved. As shown in FIGS. 9 and 10, the smaller the volume of the cavity 511 (the "front cavity" in FIG. 10), the more backward the frequency position of the resonance peak in the frequency response at the sound guiding hole 512. For the sake of easy explanation, in the embodiments of this specification, the volume of the cavity may be regarded as being approximately directly proportional to the product of the area of the diaphragm and the effective height h. The effective height h may refer to the height of the cavity 511 along the vibration direction of the diaphragm 521. In some embodiments, the effective height h of the cavity is 3 mm or less, preferably, the effective height h of the cavity is 2 mm or less, preferably, the effective height h of the cavity is 1 mm or less, more preferably, the effective height h of the cavity is 0.5 mm or less, and still more preferably, the effective height h of the cavity is 0.4 mm or less. In some embodiments, by setting the volume of the cavity 511, the frequency of the resonance peak in the frequency response at the sound guiding hole 512 can be made 3 kHz or more, preferably, by setting the volume of the cavity 511, the frequency of the resonance peak in the frequency response at the sound guiding hole 512 can be made 5 kHz or more, more preferably, by setting the volume of the cavity 511, the frequency of the resonance peak in the frequency response at the sound guiding hole 512 can be made 7 kHz or more.

[0065] The form of the diaphragm also affects the volume of the cavity. Since the diaphragm of the acoustic driver has a certain vibration amplitude when vibrating, it is necessary to ensure that the volume of the cavity is small and at the same time reserve a certain vibration space for the diaphragm, so as to prevent the diaphragm from colliding with the housing structure and generating a cracking sound when vibrating. Therefore, the gap from the tip of the diaphragm (that is, the end face of the diaphragm facing the cavity) to the cavity toward the inner wall of the diaphragm needs to be larger than the vibration amplitude of the diaphragm.

[0066] In some embodiments, the diaphragm may be a spherical diaphragm or a conical diaphragm. As shown in FIG. 11(a), when the diaphragm is a spherical diaphragm or a conical diaphragm, the protrusions at the tip of the diaphragm 1110 and the edge 1111 protruding outward are higher than other parts (i.e., the tip of the diaphragm 1110 is closer to the inner wall of the cavity), so it is necessary to reserve additional volume in the cavity to prevent the tip of the diaphragm 1110 from colliding with the inner wall of the cavity. In some embodiments, the diaphragm may be a planar diaphragm. In the embodiments of this specification, the planar diaphragm may be a diaphragm whose shape is planar or substantially planar. As shown in FIG. 11(b), when the diaphragm is the planar diaphragm 1120, the distance between the planar diaphragm 1120 and the inner wall of the cavity facing its position is smaller than that of the spherical diaphragm or the conical diaphragm, which helps to reduce the volume of the cavity. However, since the edge 1121 protrudes outward with respect to the planar diaphragm 1120, it is still necessary to maintain a certain distance between the planar diaphragm 1120 and the inner wall of the cavity facing its position. As shown in FIG. 11(c), in some embodiments, in order to further reduce the distance between the diaphragm 1130 and the inner wall of the cavity, the edge 1131 of the diaphragm 1130 may be recessed in the direction away from the cavity. In this case, the cavity of the housing structure does not need to reserve space for the edge 1131, so by reducing the volume of the cavity, the high-frequency resonance peak position at the sound guiding hole on the cavity is at a high frequency level, improving the acoustic output effect of the acoustic output device.

[0067] In some embodiments, by adjusting the size of the sound guiding hole (for example, the sound guiding hole 512), the acoustic output effect at high frequencies of the acoustic output device can be improved. As shown in FIG. 12, the larger the size of the sound guiding hole, the more backward the position of the resonance peak in the frequency response at the sound guiding hole. In some embodiments, the cross-sectional area of the sound guiding hole is 2 0.25 mm or more, preferably 2 0.5 mm or less, preferably 2 1 mm or more, preferably 2The above, preferably 4 mm 2 or less, more preferably 7 mm 2 or more, still more preferably 10 mm 2 or more. In some embodiments, by setting the cross-sectional area of the sound guiding hole, the frequency of the resonance peak in the frequency response at the sound guiding hole can be made 3 kHz or more, preferably, by setting the volume of the sound guiding hole, the frequency of the resonance peak in the frequency response at the sound guiding hole can be made 4 kHz or more, and more preferably, by setting the volume of the sound guiding hole, the frequency of the resonance peak in the frequency response at the sound guiding hole can be made 5 kHz or more.

[0068] Returning to FIG. 6, when the frequency is 3 kHz or less, the amplitude value of the frequency response corresponding to the sound guiding hole on the front of the acoustic driver is higher than the amplitude value of the frequency response corresponding to the sound guiding hole (i.e., the pressure relief hole) on the back of the acoustic driver. Therefore, at 3 kHz or less, the cancellation effect in the far field of the sound radiated from the sound guiding hole on the front of the acoustic driver and the sound radiated from the sound guiding hole on the back of the acoustic driver is weakened, and there may be a large sound leakage in the acoustic output device. In some embodiments, considering that the human ear is not sensitive to sound leakage in the frequency band of 500 Hz or less, the sound leakage in the 500 Hz to 3 kHz frequency band of the acoustic output device may be further reduced. Taking the acoustic output device 500 as an example, in some embodiments, by increasing the size and / or number of the sound guiding holes 524, the amplitude value of the frequency response corresponding to the sound guiding holes 524 is increased, so that the difference between the frequency response corresponding to the sound guiding holes 512 and the frequency response corresponding to the sound guiding holes 524 within the frequency band range of 500 Hz to 3 kHz of the acoustic output device can be reduced. When the frequency responses corresponding to the sound guiding holes 512 and the sound guiding holes 524 are sufficiently close, by performing inverse-phase cancellation on the sound waves generated by the sound guiding holes 512 and the sound waves generated by the sound guiding holes 524, the sound leakage volume in the frequency band of the acoustic output device can be reduced. In some embodiments, by adjusting the impedance at the sound guiding holes 512 and 524 of the acoustic output device, the sound leakage in the mid-low frequency band (for example, 500 Hz to 3 kHz) of the acoustic output device can be reduced. For example, by providing an acoustic attenuation structure (such as a tuning net, tuning cotton, sound guiding tube, etc.) in the sound guiding holes 512 and / or 524, the amplitude values of the frequency responses corresponding to the two sound guiding holes can be adjusted, and the sound leakage volume at the mid-low frequencies of the acoustic output device can be further reduced. Specifically, referring to the frequency response curve corresponding to the sound guiding holes shown in FIG. 6, an attenuation mechanism having a large impedance may be provided in the sound guiding holes 512, and no attenuation mechanism or an attenuation mechanism having a small impedance may be provided in the sound guiding holes 524. In this way, the frequency responses corresponding to the two sound guiding holes can be made closer within the range of the mid-low frequency band.

[0069] In some embodiments, the cavity position of the acoustic output device may not be limited to the front of the acoustic driver described above. FIG. 13 is a schematic structural diagram of an acoustic output device according to some embodiments of the present application. As shown in FIG. 13, the acoustic output device 1300 may include a housing structure 1310 and an acoustic driver 1320 connected to the housing structure 1310. The acoustic driver 1320 may include a diaphragm 1321 and a magnetic circuit structure 1322. The diaphragm 1321 and the magnetic circuit structure 1322 are provided in order along the vibration direction of the diaphragm 1321. In some embodiments, the diaphragm 1321 may be attached to a frame (not shown), and then the frame may be fixed to the magnetic circuit structure 1322. Alternatively, the diaphragm 1321 may be directly fixedly connected to the side wall of the magnetic circuit structure 1322. The side of the diaphragm 1321 facing away from the magnetic circuit structure 1322 is the front of the acoustic driver 1320, the side of the magnetic circuit structure 1322 facing away from the diaphragm 1321 is the back of the acoustic driver 1320, and the acoustic driver 1320 radiates sound to the outside from its front and back respectively due to the vibration of the diaphragm 1321. The back of the acoustic driver 1320 and the housing structure 1310 form a cavity 1311, and sound is radiated from the back of the acoustic driver 1320 into the cavity 1311 and from the front of the acoustic driver 1320 to the outside of the acoustic output device 1300. In some embodiments, the magnetic circuit structure 1322 may include a magnetic conduction plate 1323 provided opposite to the diaphragm 1321, and one or more sound induction holes 1324 (also called pressure relief holes) are provided in the magnetic conduction plate 1323. The sound induction holes 1324 guide the sound generated by the vibration of the diaphragm 1321 from the back of the acoustic driver 1320 into the cavity 1311. In some embodiments, one or more sound induction holes 1312 may be provided in the housing structure 1310. The sound induction holes 1312 are acoustically coupled to the cavity 1311 and guide the sound radiated by the acoustic driver 1320 into the cavity 1311 to the outside of the acoustic output device 1300.In some situations, since it can be considered that the sound directly propagated externally from the front of the diaphragm 1321 and the sound induced from the sound induction hole 1312 have opposite or almost opposite phases, the front of the diaphragm 1321 and the sound induction hole 1324 can form a set of two-point sound sources as shown in FIG. 3.

[0070] In some embodiments, the diaphragm 1321 may be fitted into the side wall of the housing structure 1310, and the sound generated from the front of the diaphragm 1321 may be directly propagated externally. For example, mounting holes (not shown) may be provided in the side wall of the housing structure 1310, and the diaphragm 1321 is located in the mounting holes. In some embodiments, the diaphragm 1321 may not be located in the housing structure 1310 further. For example, the side having the diaphragm 1321 in the acoustic driver 1320 may protrude outward or recess inward with respect to the housing structure 1310, and the acoustic driver 1320 may be fixedly connected to the housing structure 1310 by the magnetic circuit structure 1322.

[0071] FIG. 14 is a frequency response graph corresponding to the front and back of the acoustic driver according to some embodiments of the present application. Referring to FIGS. 2 and 14, within the frequency range of 100 Hz to 10 kHz, the consistency of the frequency responses corresponding to the front and back of the acoustic driver 1320 in the acoustic output device 1300 according to this embodiment is significantly improved compared to the consistency of the frequency responses corresponding to the front and back of the acoustic driver 120 in the acoustic output device 100. In such a situation, since the phases of the sound waves on the front and back of the acoustic driver 1320 are opposite or almost opposite, the sound waves radiated from the front and back of the acoustic driver 1320 can cancel each other out in the far field, thereby improving the sound leakage reduction effect in each frequency band of the acoustic output device 1300.

[0072] In some embodiments, by adjusting the volume of the cavity 1311, the acoustic output effect of the acoustic output device 1300 at high frequencies can be improved. As shown in FIG. 15, in the mid-high frequency band (for example, 3 kHz to 7 kHz), when the volume of the cavity 1311 (also referred to as the rear cavity here) is small ( "Small rear cavity volume - front" shown in FIG. 15), the frequency response curve corresponding to the front of the acoustic driver 1320 is flatter than the frequency response curve corresponding to the front of the acoustic driver 1320 when the volume of the cavity 1311 is large ( "Large rear cavity volume - front" shown in FIG. 15). That is, the smaller the volume of the cavity 1311, the higher the mid-high frequency response at the front of the acoustic driver 1320. Also, when the volume of the cavity 1311 is small ( "Small rear cavity volume - back" shown in FIG. 15), the frequency response curve corresponding to the back of the acoustic driver 1320 has a higher resonance peak position compared to the frequency response curve corresponding to the back of the acoustic driver 1320 when the volume of the cavity 1311 is large ( "Large rear cavity volume - back" shown in FIG. 15). That is, the smaller the volume of the cavity 1311, the later the frequency of the resonance peak corresponding to the back of the acoustic driver 1320.

[0073] In some embodiments, by adjusting the effective height of the cavity 1311, the acoustic output effect at high frequencies of the acoustic output device 1300 can be improved. In some embodiments, the effective height h of the cavity is 3 mm or less, preferably, the effective height h of the cavity is 2 mm or less, preferably, the effective height h of the cavity is 1 mm or less, more preferably, the effective height h of the cavity is 0.5 mm or less, preferably, the effective height h of the cavity is 0.4 mm or less, more preferably, the effective height h of the cavity is 0.2 mm or less. In some embodiments, by setting the volume of the cavity 1311, the frequency of the resonance peak in the frequency response at the sound guiding hole 1312 can be made 2.5 kHz or higher, preferably, by setting the volume of the cavity 1311, the frequency of the resonance peak in the frequency response at the sound guiding hole 1312 can be made 5 kHz or higher, more preferably, by setting the volume of the cavity 1311, the frequency of the resonance peak in the frequency response at the sound guiding hole 1312 can be made 7 kHz or higher. More preferably, by setting the volume of the cavity 1311, the frequency of the resonance peak in the frequency response at the sound guiding hole 1312 can be made 10 kHz or higher. For details of the volume of the cavity and the effective height h, reference can be made to FIG. 10 of the specification of the present application and its related content.

[0074] In some embodiments, by adjusting the size of the sound guiding hole 1312, the acoustic output effect of the acoustic output device at high frequencies can be improved. As shown in FIG. 16, in the mid-high frequency band (for example, 3 kHz to 7 kHz), the frequency response curve corresponding to the front of the acoustic driver 1320 when the sound guiding hole 1312 is large (the "large sound guiding hole - front" shown in FIG. 16) is flatter than the frequency response curve corresponding to the front of the acoustic driver 1320 when the size of the sound guiding hole 1312 is small (the "small sound guiding hole - front" shown in FIG. 16). That is, the larger the size of the sound guiding hole 1312, the higher the mid-high frequency response of the front of the acoustic driver 1320. Also, the frequency response curve corresponding to the back of the acoustic driver 1320 when the size of the sound guiding hole 1312 is large (the "large sound guiding hole - back" shown in FIG. 16) has a higher resonance peak position than the frequency response curve corresponding to the back of the acoustic driver 1320 when the size of the sound guiding hole 1312 is small (the "small sound guiding hole - back" shown in FIG. 16). That is, the larger the size of the sound guiding hole 1312, the more backward the frequency of the resonance peak corresponding to the back of the acoustic driver 1320, and the higher the mid-high frequency response of the acoustic output device. In some embodiments, the cross-sectional area of the sound guiding hole is 0.25 mm 2 or more, preferably 0.5 mm 2 or less, preferably 1 mm 2 or more, preferably 2 mm 2 or more, preferably 4 mm 2 or less, more preferably 7 mm 2 or more, even more preferably 10 mm 2 or more. In some embodiments, by setting the cross-sectional area of the sound guiding hole, the frequency of the resonance peak in the frequency response of the sound guiding hole can be made 3 kHz or more. Preferably, by setting the volume of the sound guiding hole, the frequency of the resonance peak in the frequency response of the sound guiding hole can be made 4 kHz or more. More preferably, by setting the volume of the sound guiding hole, the frequency of the resonance peak in the frequency response of the sound guiding hole can be made 5 kHz or more.

[0075] In some embodiments, by adjusting the position of the sound guiding hole 1312, the acoustic output effect of the acoustic output device at high frequencies can be improved. In some embodiments, the sound guiding hole may be close to the central position of the side wall (hereinafter abbreviated as the front side wall of the housing structure) facing the front or back surface of the acoustic driver of the housing structure. When the sound guiding hole is close to the central position of the front side wall of the housing structure, the frequency response curves of the front and back surfaces of the acoustic driver 1320 have high consistency. In such a situation, since the phases of the sound waves radiated from the front and back surfaces of the acoustic driver 1320 are opposite or substantially opposite, the sound waves radiated from the front and back surfaces of the acoustic driver 1320 can cancel each other out in the far field, thereby improving the sound leakage reduction effect in each frequency band of the acoustic output device 1300. FIG. 17 is a schematic structural diagram of the position distribution of the sound guiding hole according to some embodiments of the present application. The sound guiding hole 1701 shown in FIG. 17(a) is away from the central position of the front side wall of the housing structure, and the sound guiding hole 1702 shown in FIG. 17(b) is close to the central position of the front side wall of the housing structure. FIG. 18 is a frequency response graph of the front and back surfaces of the acoustic driver based on the position of the sound guiding hole shown in FIG. 17(a). FIG. 19 is a frequency response graph of the front and back surfaces of the acoustic driver based on the position of the sound guiding hole shown in FIG. 17(b). As shown in FIG. 18, within the range of medium-high frequencies or high frequencies (for example, 3 kHz to 10 kHz), when the sound guiding hole 1701 is away from the central position of the front side wall of the housing structure, the difference in the frequency response curves of the front and back surfaces of the acoustic driver is large, which causes a large sound leakage in the frequency band of the acoustic output device. As shown in FIG. 19, within the range of 100 Hz to 10 kHz, when the sound guiding hole 1702 is close to the central position of the side wall of the housing structure, the consistency of the frequency response curves of the front and back surfaces of the acoustic driver is high. In such a situation, in the far field, the sound waves radiated from the front and back surfaces of the acoustic driver can cancel each other out, so that the sound leakage reduction effect in the frequency band of the acoustic output device can be improved. In addition, in other embodiments, the number of the sound guiding hole 1701 and the sound guiding hole 1702 is not limited to one, and may be further two, three or more.When a plurality of sound guiding holes are provided in the front side wall of the housing structure, these sound guiding holes may all be located at a central position close to the side wall of the housing structure, may all be located at a central position away from the side wall of the housing structure, or may be respectively located at a central position close to the side wall of the housing structure and a central position away from the side wall of the housing structure. Also, the shapes of the sound guiding hole 1701 and the sound guiding hole 1702 are not limited to the circular shape in FIG. 17, and may further be semi-circular, elliptical, etc. A person skilled in the art can adaptively adjust the number and shape of the sound guiding hole 1701 and the sound guiding hole 1702 according to the specific situation, and will not be further limited here. The application scenario where the above sound guiding holes are close to the central position of the front side wall of the housing structure is not limited to only the sound output device 1300 shown in FIG. 13, and is similarly applicable to the sound output devices in other embodiments of the present application. For example, it is applicable to the sound output devices shown in FIGS. 1, 5, 7, and 9, etc.

[0076] In some embodiments, referring to the frequency response curves corresponding to the front and back surfaces of the acoustic driver shown in FIG. 14, by adjusting the impedance at the sound guiding hole 1312 of the sound output device (for example, providing an attenuation mechanism having a certain impedance in the sound guiding hole 1312), the frequency response curves corresponding to the front and back surfaces of the acoustic driver are made closer within a certain frequency range (for example, 500 Hz to 3 kHz), thereby reducing sound leakage within the frequency range of the sound output device. For example, by providing an acoustic attenuation structure (such as a tuning net, tuning cotton, sound guiding tube, etc.) in the sound guiding hole 1312, the amplitude value of the frequency response corresponding to the back surface of the acoustic driver can be reduced, and the amplitude value may be made close to or equal to the amplitude value of the frequency response corresponding to the front surface of the acoustic driver.

[0077] FIG. 20 is a schematic structural diagram of an acoustic output device according to some embodiments of the present application. The structures of the acoustic output device 2000 as shown in FIG. 20 and the acoustic output device 1300 as shown in FIG. 13 are substantially the same. For the housing structure 2010, the acoustic driver 2020, the diaphragm 2021, the magnetic circuit structure 2022, the magnetic conduction plate 2023, the sound guiding hole 2024, and the sound guiding hole 2012, reference can be made to FIG. 13 and its related content. The acoustic output device 2000 shown in FIG. 20 is different from the acoustic output device 1300 shown in FIG. 13 in that, in some embodiments, a protection structure 2030 may be further provided outside the diaphragm 2021 to protect the diaphragm 2021. The protection structure 2030 may be fixedly connected to the housing structure 2010. In some embodiments, the protection structure 2030 is a structure that permits the sound waves generated from the front of the diaphragm 2021 to propagate to the outside. For example, the protection structure 2030 may be a filter structure. Also for example, the protection structure 2030 may be a plate structure having holes or the like. In some embodiments, there is a certain interval between the protection structure 2030 and the front of the diaphragm 2021, and this interval can prevent the diaphragm 2021 from colliding with the protection structure 2030 during the vibration process. For the type and structure of the diaphragm 2021, reference can be made to the diaphragm shown in FIG. 11 of the present application, and the description is omitted here.

[0078] FIG. 21 is a schematic structural diagram of an acoustic output device according to some embodiments of the present application. The acoustic output device 2100 shown in FIG. 21 is different from the acoustic output device 500 shown in FIG. 5 or the acoustic output device 1300 shown in FIG. 13 in that the acoustic output device 2100 shown in FIG. 21 does not include a cavity formed by a housing structure and an acoustic driver. As shown in FIG. 21, the acoustic output device 2100 may include an acoustic driver 2110, and the acoustic driver 2110 may include a diaphragm 2121 and a magnetic circuit structure 2122. The diaphragm 2121 and the magnetic circuit structure 2122 are provided in order along the vibration direction of the diaphragm 2121. In some embodiments, the diaphragm 2121 may be attached to one frame (not shown), and then the frame may be fixed to the magnetic circuit structure 2122. Alternatively, the diaphragm 2121 may be directly fixedly connected to the side wall of the magnetic circuit structure 2122. The side of the diaphragm 2121 facing away from the magnetic circuit structure 2122 is the front of the acoustic driver 2110, the side of the magnetic circuit structure 2122 facing away from the diaphragm 2121 is the back of the acoustic driver 2110, and the acoustic driver 2110 radiates sound to the outside from its front and back respectively due to the vibration of the diaphragm 2121. Sound waves are directly radiated to the outside from the front of the acoustic driver 2110. One or more sound guiding holes 2124 are provided in the magnetic conduction plate 2123 of the magnetic circuit structure 2122. The sound guiding holes 2124 directly guide the sound generated by the vibration of the diaphragm 2121 to the outside from the back of the acoustic driver 2110. In some embodiments, the acoustic output device 2100 may further include a protection structure 2130, and the protection structure 2130 may be fixedly connected to the magnetic circuit structure 2122. For details of the protection structure 2130, reference may be made to the above protection structure 2030. In some embodiments, since it can be considered that the sound guided from the sound guiding holes 2124 and the sound radiated from the front of the diaphragm 2121 have opposite or substantially opposite phases, the sound guiding holes 2124 and the front of the diaphragm 2121 can constitute a set of two-point sound sources as shown in FIG. 3.

[0079] FIG. 22 is a frequency response graph of the front and back surfaces of the acoustic output device 2100 shown in FIG. 21 of the present application. As shown in FIG. 22, when the acoustic output device 2100 does not include a cavity formed by a housing structure and an acoustic driver, the frequency responses output from the acoustic output device 2100 (the front and back surfaces of the acoustic driver 2110) are all at high frequency positions (for example, greater than 6 kHz) in the high-frequency resonance peaks. In the high-frequency band of 10 kHz or higher, in order for the acoustic output device 2100 to generate a specific sound field with a certain directivity, the directivity of sound waves at high frequencies is utilized to achieve the effect that the near-field listening volume increases and the far-field sound leakage volume decreases. In the mid-high frequency range (for example, 3 kHz to 7 kHz), the frequency responses on the front and back surfaces of the acoustic output device 2100 are very close, and the phases of the sound waves on the front and back surfaces are opposite. Therefore, the sound leakage within the frequency range of the acoustic output device 2100 can be significantly reduced. In the low-frequency band (for example, 3 kHz or lower), the frequencies on the front and back surfaces of the acoustic output device 2100 correspond and have a certain difference. However, since the human ear is not sensitive to low-frequency sound leakage, it is not necessary to weaken the far-field sound leakage within this frequency range. Preferably, a damping mechanism having a large impedance may be provided on the diaphragm 2121, or a damping mechanism may not be provided in the sound guiding hole 2124 or a damping mechanism having a small impedance may be provided. In this way, the frequency responses corresponding to the front and back surfaces of the acoustic driver 2110 can be made closer within the range of the mid-low frequency band. In this embodiment, for achieving the effect that the near-field listening volume increases and the far-field sound leakage volume decreases by utilizing the directivity of sound waves at high frequencies, reference can be made to FIG. 5 of the present application and its related description.

[0080] In some embodiments, when the user wears the above acoustic output device, the wearing position of the acoustic output device may be the upper body of the user. For example, the wearing position may be a position close to the ears on the head. As shown in FIG. 23, the rectangular structure in the figure is the acoustic output device. As shown in FIGS. 23a and 23b, the sound output position (e.g., sound guiding hole, pressure relief hole, or diaphragm) of the acoustic output device may be within the concha vector plane projection (e.g., concha cavity) or outside the concha vector plane projection. As shown in FIGS. 23c and 23d, the acoustic output device may be suspended above the ear canal by a corresponding structure (e.g., hook), but does not block the ear canal.

[0081] In some embodiments, in order to improve the acoustic output effect of the acoustic output device, the housing structure of the acoustic output device is used as a baffle, and the volume at the listening position can be increased without increasing the sound leakage in the far field. As shown in FIG. 24, the front sound output position 2410 and the back sound output position 2420 (e.g., sound guiding hole, pressure relief hole, or diaphragm) of the acoustic output device 2400 (the acoustic driver thereof) are located on both sides where the positions of the acoustic output device 2400 are opposite to each other, and are separated by the housing (e.g., housing structure) of the acoustic output device 2400. In this way, the housing of the acoustic output device 2400 can function as a baffle. In some embodiments, among the front or back of the acoustic output device 2400, the acoustic path from the side with a larger amplitude value of the high-frequency response (e.g., the side where the "sound guiding hole 1" is located in FIG. 8, the front of the acoustic driver in FIG. 18) to the ear is closer than the acoustic path from the other side to the ear. Preferably, among the front or back of the acoustic output device 2400, the side with a larger amplitude value of the high-frequency response faces the ear canal.

[0082] The principle of using the housing structure of the acoustic output device as a baffle is shown in FIG. 25. In the near field, the "baffle" (e.g., housing structure) increases the acoustic path from the sound source A 2 away from the listening position to the listening position, so as to weaken the intensity of the out-of-phase sound wave from the sound source A 2 reaching the listening position. In such a situation, the sound source A 1and sound source A 2 By weakening the degree of interference cancellation at the listening position of the sound generated from 2 and sound source A, the volume at the listening position is increased. In the far field, for sound source A of the "baffle" (housing structure) 1 and sound source A 2 the influence on the acoustic path is very small, and the sound leakage in the far field hardly changes.

[0083] Although the basic concept has been described above, from the perspective of those skilled in the art, the above detailed disclosure is clearly only illustrative and does not limit the present application. Although not explicitly described here, those skilled in the art can make various changes, improvements, and modifications to the present application. Since such changes, improvements, and modifications are proposed in the present application, such changes, improvements, and modifications still belong to the gist and scope of the exemplary embodiments of the present application.

[0084] At the same time, the present application uses specific words to describe the embodiments of the present application. For example, "one embodiment", "an embodiment", and / or "some embodiments" refer to features, structures, or characteristics related to at least one embodiment of the present application. Therefore, it should be noted that the "an embodiment" or "one embodiment" or "a variant" mentioned twice or more at different positions in this specification does not necessarily mean the same embodiment. Also, the features, structures, or characteristics of one or more embodiments of the present application can be appropriately combined.

[0085] Moreover, it will be understood by those skilled in the art that each aspect of the present application can be described and recited in a plurality of patentable classes or contexts that include a novel and useful process, machine, manufacture, or composition of matter, or a novel and useful improvement thereof. Correspondingly, each aspect of the present application may be implemented entirely in hardware, entirely in software (including firmware, resident software, microcode, etc.), or in a combination of hardware and software. Any of the above hardware or software may be referred to as a "data block", "module", "engine", "unit", "assembly", or "system". Also, each aspect of the present application may take the form of a computer product embodied in one or more computer-readable media having computer-readable program code.

[0086] A computer storage medium may include a propagated data signal having computer program code embodied therein, for example, within a baseband or as part of a carrier wave. The propagated signal may take any of a variety of forms including, for example, electromagnetic, optical, or a combination thereof. The computer storage medium may be any computer-readable medium other than a computer-readable storage medium, which medium can be used to communicate, propagate, or transport a program for use in connection with an instruction execution system, apparatus, or device. The program code located on the computer storage medium can be propagated via any appropriate medium including wireless, cable, fiber optic cable, RF, or similar media, or any combination of the above media.

[0087] The computer program code required for the operation of each part of this application can be described in one or more programming languages, including object-oriented programming languages such as Java, Scala, Smalltalk, Eiffel, JADE, Emerald, C++, C#, VB.NET, Python, conventional procedural programming languages such as the "C" programming language, Visual Basic, Fortran2003, Perl, COBOL2002, PHP, ABAP, dynamic programming languages such as Python, Ruby, and Groovy, or other programming languages. The program code can be executed entirely on the user computer, or executed on the user computer as an independent software package, or executed partially on the user computer or a remote computer, or executed entirely on a remote computer or server. In the latter situation, the remote computer can be connected to the user computer by any network format such as a local area network (LAN) or a wide area network (WAN), or connected to an external computer (e.g., via the Internet), or used in a cloud computing environment or as a service such as software as a service (SaaS).

[0088] Also, unless otherwise recited in the claims, the order of the processing elements and sequences, the use of numbers, letters of the alphabet, or other names in the above description of the present application do not limit the order of the flow and method of the present application. Although various examples in the above disclosure have considered some embodiments of the invention that are currently considered useful, it should be understood that such details serve only the purpose of explanation and the additional claims are not limited to the disclosed embodiments. On the contrary, the claims are intended to cover all modifications and equivalent combinations that conform to the substance and scope of the embodiments of the present application. For example, the system assembly described above may be implemented by a hardware device, but may also be implemented by software solution means only, for example, installing the system described in a conventional server or mobile device.

[0089] Similarly, it should be noted that in order to simplify the description disclosed in the present application and assist in the understanding of one or more embodiments of the invention, in the description of the previous embodiments of the present application, multiple types of features may be integrated into one embodiment, drawing, or description thereof. However, such a disclosure method does not mean that the features required for the subject matter of the present application are more than the features recited in the claims. In fact, the features of the embodiment are less than all the features of a single embodiment of the above disclosure.

[0090] In some embodiments, numbers are used to describe components and the number of attributes. It should be understood that the numbers used in the description of such embodiments are, in some instances, modified using modifiers such as "about", "substantially", or "approximately". Unless otherwise specified, "about", "substantially", or "approximately" indicate that the above numbers allow for a variation of ±20%. Correspondingly, in some embodiments, the numerical parameters used in the specification and claims are all approximate values that can be changed according to the characteristics required for individual embodiments. In some embodiments, numerical parameters should adopt a method of considering a predetermined number of significant digits and retaining a general number of digits. In some embodiments of the present application, the numerical ranges and parameters for confirming the scope are approximate values. However, in specific embodiments, such numerical settings are made as accurate as possible within the executable range.

[0091] Regarding each patent, patent application, patent application publication, and other materials cited by the present application, such as articles, books, specifications, publications, documents, etc., in particular, their entire contents are incorporated by reference into the present application. Exclude the application history files that do not match the content of the present application or conflict with it, and also exclude the files (those added to the present application currently or subsequently) that limit the broadest scope of the claims of the present application. In addition, if the descriptions, definitions, and / or uses of terms in the attached materials of the present application do not match or conflict with the above content of the present application, the descriptions, definitions, and / or uses of terms in the present application shall be taken as the standard.

[0092] Finally, it should be understood that the above embodiments in the present application are only for explaining the principles of the embodiments of the present application. Other variations may fall within the scope of the present application. Therefore, by way of example and not limitation, alternative configurations of the embodiments of the present application can be regarded as consistent with the teachings of the present application. Correspondingly, the embodiments of the present application are not limited to the embodiments clearly described and recited in the present application.

Claims

1. An audio output device, comprising: an acoustic driver including a diaphragm and a magnetic circuit structure, wherein a side of the diaphragm facing away from the magnetic circuit structure is a front surface of the acoustic driver, a side of the magnetic circuit structure facing away from the diaphragm is a back surface of the acoustic driver, and the acoustic driver radiates sound to the outside from its front surface and back surface respectively due to vibration of the diaphragm; and a housing structure configured to mount the acoustic driver. One of the front surface and the back surface of the acoustic driver forms a cavity together with the housing structure, and radiates sound into the cavity. A height of the cavity along a vibration direction of the diaphragm is 3 mm or less. The housing structure includes at least one sound guiding hole, the at least one sound guiding hole is acoustically coupled to the cavity, and the acoustic driver guides sound radiated into the cavity to the outside of the audio output device. The other one of the front surface and the back surface of the acoustic driver does not form a cavity together with the housing structure, and radiates sound to the outside of the audio output device without passing through the cavity. An audio output device, wherein sound radiated from the front surface of the acoustic driver has a phase opposite to that of sound radiated from the back surface of the acoustic driver.

2. The audio output device according to claim 1, wherein the at least one sound guiding hole of the housing structure is close to a central position on a side of the housing structure facing the acoustic driver.

3. The cross-sectional area of the at least one sound guiding hole of the housing structure is 0.25 mm ２ or more, the acoustic output device according to claim 1 or 2.

4. The magnetic circuit structure includes a magnetic conduction plate provided opposite to the diaphragm, and the magnetic conduction plate includes at least one sound guiding hole for guiding sound generated by vibration of the diaphragm from the back surface of the acoustic driver. The audio output device according to any one of claims 1 to 3.

5. The front surface of the acoustic driver and the housing structure form the cavity, and the at least one sound guiding hole of the magnetic conduction plate guides sound generated by vibration of the diaphragm from the back surface of the acoustic driver to the outside of the audio output device. The audio output device according to claim 4.

6. A sound guiding tube is provided along a direction away from the diaphragm in the at least one sound guiding hole of the magnetic conduction plate, and the sound guiding tube guides sound radiated from the at least one sound guiding hole of the magnetic conduction plate to the outside of the audio output device. The audio output device according to claim 4 or 5.

7. The at least one sound guiding hole of the magnetic conduction plate includes a first hole portion and a second hole portion provided in order from the inside, the first hole portion and the second hole portion penetrate through, and the diameter of the second hole portion is larger than the diameter of the first hole portion. The acoustic output device according to any one of claims 4 to 6.

8. The back surface of the acoustic driver and the housing structure form the cavity, and a protection structure provided for the diaphragm is further provided on the front surface of the acoustic driver. The acoustic output device according to any one of claims 1 to 4.

9. The cavity guides sound to the outside of the acoustic output device through a first sound guiding hole, and guides sound to the outside of the acoustic output device through a second sound guiding hole on a surface different from the surface of the acoustic cavity formed by the acoustic driver, and the first sound guiding hole and the second sound guiding hole have different acoustic impedances. The acoustic output device according to any one of claims 1 to 8.

10. Among the front surface or the back surface of the acoustic driver, the surface with a larger amplitude value of the high-frequency response has an acoustic path to the ear closer than the other surface. The acoustic output device according to any one of claims 1 to 9.

11. Among the front surface or the back surface of the acoustic driver, the surface with a larger amplitude value of the high-frequency response faces the ear canal. The acoustic output device according to any one of claims 1 to 10.

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