TWI727168B - Symmetrical earphone device - Google Patents

Abstract

A symmetrical earphone device includes a body, a first proximity sensor, a second proximity sensor, a communication module, a processing module and a playing module. The body includes an outer ear ring. The outer ear ring includes a central symmetry plane, a left half ring, and a right half ring. The central symmetry plane separates the left half ring and the right half ring from opposite sides. The first proximity sensor is disposed on the left half ring. The first proximity sensor detects and correspondingly outputs a first detection signal. The second proximity sensor is disposed on the right half ring. The second proximity sensor detects and correspondingly outputs a second detection signal. The communication module receives an audio signal. The audio signal includes left channel audio and right channel audio. The playing module is electrically connected to the communication module. The processing module selectively controls the playing module to play the left channel audio or controls the playing module to play the right channel audio according to the first detection signal and the second detection signal.

Description

Symmetrical earphone device

The present invention relates to an earphone device, in particular to a symmetrical earphone device.

A headset is a small sound output device, which is one of the indispensable accessories in multimedia products (such as computers or smart phones). The user can receive and play the audio source output by the multimedia product through the headset, so as to listen to the audio alone without affecting others.

Generally speaking, a headset usually includes a pair of earpieces (left earpiece and right earpiece), where the left earpiece is responsible for playing the left channel of the audio source, and the right earpiece is responsible for playing the right channel of the audio source.

However, for flat-head earphones or earbuds, since the left earphone and the right earphone are of the same shape and symmetrical (for example, both are circular), it is easy for the user to use the left earphone and the right earphone. Wrong wearing means that the left earpiece is mistakenly worn to the right ear, and the right earpiece is mistakenly worn to the left ear, which will affect the sound effect and listening experience.

In view of this, in one embodiment, a symmetrical earphone device is provided for receiving an external audio signal. The audio signal includes a left channel audio and a right channel audio. The symmetrical earphone device includes a main body and a second audio source. A proximity sensor, a second proximity sensor, a communication module, a playback module and a processing module. The body includes an outer earplug ring. The outer earplug ring includes a central symmetry plane, a left half ring and a right half ring. The central symmetry plane separates the left half ring and the right half ring on opposite sides. The left half ring and the right half ring are based on the central symmetry plane. Symmetrical to each other. The first proximity sensor is arranged on the left half of the outer earplug ring, and the first proximity sensor detects and correspondingly outputs a second detection signal. The second proximity sensor is arranged on the right half of the outer earplug ring, and the second proximity sensor detects and correspondingly outputs a second detection signal. The communication module receives external audio signals. The playing module is arranged in the main body and is electrically connected to the communication module. The processing module is electrically connected to the first proximity sensor, the second proximity sensor, the communication module, and the playback module. The processing module selectively controls the playback module according to the first detection signal and the second detection signal. The group plays the left channel audio, or selectively controls the playback module to play the right channel audio.

In summary, according to the symmetrical earphone device of the embodiment of the present invention, the left half ring and the right half ring of the earplug ring outside the body are respectively provided with a first proximity sensor and a second proximity sensor, so that the processing module can According to the difference between the first detection signal and the second detection signal, it is determined whether the user wears the left ear or the right ear. When the user wears the left ear, the left channel audio is played, and when the user wears the right ear, it is The right channel audio is played, so that there will be no wearing errors and ensure that the user gets the best listening effect.

Fig. 1 is a perspective view of an embodiment of a symmetrical earphone device of the present invention, Fig. 1A is a partially enlarged perspective view of an embodiment of a symmetrical earphone device of the present invention, Fig. 2 is a plan view of an embodiment of a symmetrical earphone device of the present invention, and Fig. 3 is The device block diagram of an embodiment of the symmetrical earphone device of the present invention. As shown in FIGS. 1 to 3, this embodiment discloses a pair of symmetrical earphone devices 1 and 2, which can be worn by the user in the left and right ears to listen to audio transmitted by multimedia products (such as computers or smart phones). Among them, the two symmetrical earphone devices 1 and 2 have the same structure, and the following embodiments only use one of them for detailed description, which is described first.

As shown in FIGS. 1 to 3, the symmetrical earphone device 1 may be an earbuds or earbuds. The symmetrical earphone device 1 includes a symmetric earbud body 10 and a first proximity sensor. 15 (proximity sensor), a second proximity sensor 16 (proximity sensor), a communication module 17, a processing module 18, and a playback module 19.

As shown in Figures 1, 1A and 2, the body 10 includes an outer earplug ring 11, a sound opening 12, and a back cover 13. The outer earplug ring 11 includes a central plane of symmetry S (plane of symmetry) and a left half Ring 111 and a right half ring 112. Wherein, the central symmetry plane S separates the left half ring 111 and the right half ring 112 on two opposite sides, and the left half ring 111 and the right half ring 112 are symmetrical to each other according to the central symmetry plane S. As shown in Figures 1 and 2, in this embodiment, the outer earplug ring 11 is a circular ring, but not limited to this. The central symmetry plane S can pass through the center position C of the outer earplug ring 11, and the outer earplug ring 11 The earplug ring 11 is divided into a left half ring 111 and a right half ring 112 that are in a mirror-reflecting relationship with each other, and exhibits a mirror symmetry (Mirror symmetry).

As shown in FIGS. 1, 1A and 2, the sound opening 12 and the rear cover 13 are located at two axially opposite ends of the outer earplug ring 11. For example, as shown in FIG. 1A, the outer earplug ring 11 has a central axis CL passing through its annular center position C, and the central axis CL is located on the central symmetry plane S, the outer earplug ring 11 has two opposite axial ends, and the back cover 13 It is connected to one end of the outer earplug ring 11 to form a hollow shell, and the sound outlet opening 12 is provided at the other end of the outer earplug ring 11 to guide the sound. The body 10 further includes an extension rod 14 which extends from the rear cover 13. In this embodiment, the extension rod 14 extends in the radial direction of the outer earplug ring 11 and conforms to the central symmetry plane S of the outer earplug ring 11. It is bilaterally symmetrical, that is, the central symmetry plane S can divide the body 10 as a whole into a left half and a right half that are bilaterally symmetrical to each other.

As shown in FIGS. 3 and 4, the first proximity sensor 15 can be arranged on the left half ring 111 of the outer earplug ring 11. The first proximity sensor 15 can detect and correspondingly output the first detection signal 15S. The two proximity sensors 16 are disposed on the right half ring 112 of the outer earplug ring 11, and the second proximity sensor 16 can detect and correspondingly output a second detection signal 16S. For example, the first proximity sensor 15 and the second proximity sensor 16 can both be an infrared proximity sensor, so that the first proximity sensor 15 and the second proximity sensor 16 can be respectively external It emits infrared sensing signals (such as the first sensing signal and the second sensing signal). When the infrared sensing signal is transmitted to the object, it can respectively generate infrared reflection signals (ie the first sensing signal 15S and the second sensing signal). Signal 16S). In other embodiments, the first proximity sensor 15 and the second proximity sensor 16 can also be other optical proximity sensors, and the first detection signal and the second detection signal are of other forms. The light reflection signal, or the first proximity sensor 15 and the second proximity sensor 16 may also be radio wave proximity sensors, and the first detection signal and the second detection signal are respectively reflected radio waves.

As shown in FIG. 5, in one embodiment, when the user needs to listen to audio, the outer earplug ring 11 and the sound opening 12 of the body 10 can be correspondingly inserted into the concha cavity E1 of the ear, so that the sound is emitted When the opening 12 is led out, it can enter the ear canal. In an embodiment, the positions of the first proximity sensor 15 and the second proximity sensor 16 may correspond to the tragus E2 of the ear. Specifically, as shown in FIG. 5, when the user inserts the outer earplug ring 11 into the left ear E, the first proximity sensor 15 can be correspondingly shielded by the tragus E2 of the left ear E. As shown in Fig. 6, when the user inserts the outer earplug ring 11 into the right ear E', the second proximity sensor 16 can be correspondingly shielded by the tragus E2 of the right ear E'.

As shown in FIGS. 1A and 4, in one embodiment, the outer earplug ring 11 has a vertical centerline V passing through the center position C, the vertical centerline V is perpendicular to the center axis CL, and the vertical centerline V, the center axis CL and The center positions C are all located on the central symmetry plane S (Figure 1A). Taking the vertical center line V as the 0° reference line, there is a first included angle θ1 between the first line L1 of the first proximity sensor 15 to the center position C and the vertical center line V, and the first included angle θ1 may be between Between -20°～-120°. There is a second included angle θ2 between the second line L2 from the second proximity sensor 16 to the center position C and the vertical center line V, and the second included angle θ2 is between 20° and 120°.

As shown in Figure 4, since the size of each person’s ear shape or tragus is not the same, in some embodiments, the first included angle θ1 may be between -55° and -85°, -65° and -85°. ° or between -75° and -85°, the second included angle θ2 can be between 55° and 85°, between 65° and 85°, or between 75° and 85°, so that the first proximity The position of the sensor 15 and the second proximity sensor 16 may correspond to the tragus E2 of most people's ears. In some embodiments, the first proximity sensor 15 and the second proximity sensor 16 can also be symmetrically arranged on the left half ring 111 and the right half ring 112 according to the central symmetry plane S, that is, the first The absolute values of the included angle θ1 and the second included angle θ2 are the same (for example, the absolute values of the first included angle θ1 and the second included angle θ2 are both 80°), but this is not limited. In other embodiments, the first proximity sensor 15 and the second proximity sensor 16 may also be asymmetrical, for example, the absolute values of the first included angle θ1 and the second included angle θ2 are slightly different, for example, The angle difference between the absolute value of the first included angle θ1 and the second included angle θ2 may be less than 15° (for example, the absolute value of the first included angle θ1 is 85°, and the absolute value of the second included angle θ2 is 75°).

As shown in FIG. 3, the symmetrical earphone device 1 receives an external audio signal A through the communication module 17, where the audio signal A can be a stereo signal including a left channel audio and a right channel audio. In some embodiments, the communication module 17 may be a wired line (as shown in FIG. 2, where the wired line is connected to an extension rod 14 extending from the rear cover 13) to pass through a plug (such as 3.5mm TRS, 3.5mm TRS, 3.5mm TRS, 3.5mm TRS, 3.5mm mm TRRS, USB Type-C or Lightning, etc.) is connected to the headphone jack of the multimedia product, and can receive the audio signal A from the multimedia product through a wired line. Or, in another embodiment, the communication module 17 may also be a wireless communication module (such as a Bluetooth module) and is arranged inside the main body 10 to receive the audio signal A through wireless transmission.

As shown in FIG. 3, the processing module 18 may be a microcontroller (Micro Control Unit, MCU) or a microprocessor (Micro Processing Unit, MPU) and is electrically connected to the first proximity sensor 15, the second proximity sensor The device 16, the communication module 17, and the playback module 19. The playback module 19 may be a speaker and be arranged in the main body 10. In some embodiments, the playback module 19 may be a moving coil speaker, a moving iron speaker, a piezoelectric speaker, etc., which is not limited. The processing module 18 selectively controls the playback module 19 to play the left channel audio or selectively controls the playback module 19 to play the right channel audio according to the first detection signal 15S and the second detection signal 16S. The audio is transmitted from the output opening 12.

In one embodiment, the processing module 18 can determine whether the playback module 19 plays the left channel audio or the right channel audio by comparing the intensity of the first detection signal 15S with the intensity of the second detection signal 16S. For example, the processing module 18 controls the playing module 19 to play the left channel audio according to the intensity of the first detection signal 15S being less than the intensity of the second detection signal 16S. Alternatively, the processing module 18 controls the playing module 19 to play the right channel audio according to when the intensity of the first detection signal 15S is greater than the intensity of the second detection signal 16S. For example, as shown in FIG. 5, assuming that the first proximity sensor 15 and the second proximity sensor 16 are both infrared proximity sensors, when the user inserts the earplug ring 11 outside the body 10 into the left At ear E, the first proximity sensor 15 will be correspondingly shielded by the tragus E2 of the left ear E, so that the intensity of the first detection signal 15S received by the first proximity sensor 15 is 0 or very weak. The second proximity sensor 16 is not covered by the ear shell, so that the intensity of the second detection signal 16S received by the second proximity sensor 16 is greater than the intensity of the first detection signal 15S. At this time, the processing mode The group 18 can determine that the user is wearing the left ear and control the playback module 19 to play the left channel audio.

As shown in FIG. 6, when the user inserts the earplug ring 11 outside the body 10 into the right ear E', the second proximity sensor 16 can be correspondingly shielded by the tragus E2 of the right ear E', so that the second proximity The intensity of the second detection signal 16S received by the sensor 16 is 0 or very weak. The first proximity sensor 15 is not covered by the ear shell, and the intensity of the first detection signal 15S received by the first proximity sensor 15 is greater than the intensity of the second detection signal 16S. At this time, the processing mode The group 18 can determine that the user is wearing the right ear and control the playback module 19 to play the right channel audio.

Thereby, two proximity sensors (the first proximity sensor 15 and the second proximity sensor 16) are provided through the symmetrical earphone devices 1, 2 and the processing module 18 can interact with each other according to the first detection signal The second detection signal determines whether the user wears the left ear or the right ear, and then outputs the correct sound channel, that is, when the user wears the left ear, the left channel audio is played, and when the user wears the right ear The right channel audio is played at any time, so there will be no wearing errors, so as to ensure that users can hear the correct stereo and get the best listening effect. In addition, the user does not need to waste time to determine whether each symmetrical earphone device 1 and 2 is a left-ear earphone or a right-ear earphone, thereby improving the convenience of use.

Furthermore, two proximity sensors (the first proximity sensor 15 and the second proximity sensor 16) are provided with the symmetrical earphone devices 1, 2 so that each symmetrical earphone device 1, 2 can be independently determined Whether the user wears the left ear or the right ear does not need to wear both of the two symmetrical earphone devices 1 and 2 to make a judgment. For example, when the user only wears one of the symmetrical earphone devices 1 on the left ear E (as shown in FIG. 5) and the other symmetrical earphone device 2 is not worn, the symmetrical earphone device 1 can still determine the user alone The left ear is worn and the left channel audio is played. Or, when the two symmetrical earphone devices 1 and 2 are worn by different users, the correct judgment and channel output can also be performed. For example, when one of the symmetrical earphone devices 1 is worn on the left ear of a user, the other When a symmetrical earphone device 2 is also worn on the left ear of another user, the two symmetrical earphone devices 1 and 2 can be independently judged to be worn on the left ear of the user and both play the left channel audio.

In some embodiments, the processing module 18 may also compare the intensity of the first detection signal 15S and the intensity of the second detection signal 16S to an intensity threshold respectively to determine whether the playback module 19 plays the left channel audio or the right channel audio. Channel audio. For example, the processing module 18 controls the playback module 19 to play the left channel audio when the intensity of the first detection signal 15S is less than an intensity threshold, and the intensity of the second detection signal 16S is greater than the aforementioned intensity threshold. Alternatively, the processing module 18 controls the playing module 19 to play the right channel audio when the intensity of the first detection signal 15S is greater than the intensity threshold, and the second detection signal 16S is less than the intensity threshold.

In an embodiment, the symmetrical earphone device 1'may be provided with a photosensitive element to further improve the accuracy of the judgment of the processing module 18. As shown in FIG. 7, in this embodiment, the symmetrical earphone device 1'includes a first photosensitive element 21 and a second photosensitive element 22. The first photosensitive element 21 and the second photosensitive element 22 may be photosensitive coupling elements (charge -coupled device (CCD) or complementary metal oxide semiconductor active pixel sensor (CMOS Active pixel sensor) to receive external light signals. The first photosensitive element 21 is arranged on the left half ring 111 of the outer earplug ring 11 and adjacent to the first proximity sensor 15, and the second photosensitive element 22 is arranged on the right half ring 112 of the outer earplug ring 11 and adjacent to the second proximity sensor.感器16。 Sensor 16.

Please refer to FIGS. 7 and 8, the processing module 18 is further electrically connected to the first photosensitive element 21 and the second photosensitive element 22 to further output a sound source according to the sensing results of the first photosensitive element 21 and the second photosensitive element 22 The left channel audio or right channel audio of signal A. The sensing result includes whether the first photosensitive element 21 receives an external light signal and whether the second photosensitive element 22 receives an external light signal.

For example, as shown in FIGS. 5 and 7, when the user inserts the outer earplug ring 11 of the symmetrical earphone device 1'into the left ear E, the first proximity sensor 15 and the first photosensitive element 21 can be received The tragus E2 of the left ear E is correspondingly shielded, and the second proximity sensor 16 and the second photosensitive element 22 are not shielded by the ear shell. Therefore, the intensity of the second detection signal 16S received by the second proximity sensor 16 Is greater than the intensity of the first detection signal 15S received by the first proximity sensor 15, and the first photosensitive element 21 fails to receive the external light signal, and the second photosensitive element 22 can receive the external light signal. , The processing module 18 can determine that the user is wearing the left ear and control the playback module 19 to play the left channel audio.

6 and 7, when the user inserts the outer earplug ring 11 of the symmetrical earphone device 1'into the right ear E', the second proximity sensor 16 and the second photosensitive element 22 can be received by the right ear The tragus E2 of E'is correspondingly shielded, and the first proximity sensor 15 and the first photosensitive element 21 are not shielded by the ear shell. Therefore, the intensity of the second detection signal 16S received by the second proximity sensor 16 is less than The first proximity sensor 15 receives the intensity of the first detection signal 15S, and the first photosensitive element 21 can receive the external light signal, but the second photosensitive element 22 fails to receive the external light signal. At this time, the processing module 18 can determine that the user is wearing the right ear and control the playback module 19 to play the right channel audio. In this way, this embodiment can further make judgments based on changes in external light, so as to improve the accuracy of the judgment of the processing module 18.

In some embodiments, the processing module 18 may also compare the external light signals received by the first photosensitive element 21 and the second photosensitive element 22 to a brightness threshold respectively to determine to output the left channel audio or the right channel audio. For example, the processing module 18 controls the playback module 19 when the brightness of the external light signal received by the first photosensitive element 21 is less than a brightness threshold, and the brightness of the external light signal received by the second photosensitive element 22 is greater than the brightness threshold. Play the left channel audio. Alternatively, the processing module 18 controls the playback module when the brightness of the external light signal received by the first photosensitive element 21 is greater than a brightness threshold, and the brightness of the external light signal received by the second photosensitive element 22 is less than the brightness threshold 19Play right channel audio.

In some embodiments, the symmetrical earphone device 1'may also have only one photosensitive element (the first photosensitive element 21 or the second photosensitive element 22), for example: the symmetrical earphone device 1'only has the first photosensitive element 21 outside. On the left half ring 111 of the earplug ring 11, the processing module 18 can control the playback module 19 to play the left channel audio or right channel audio of the audio source signal A through the sensing result of a single photosensitive element, so it is the processing module 18 When the intensity of the first detection signal 15S is less than the intensity of the second detection signal 16S, and the photosensitive element fails to receive the external light signal, the playback module 19 is controlled to play the left channel audio. When the intensity of the first detection signal 15S is greater than the intensity of the second detection signal 16S, and the photosensitive element receives the external light signal, the processing module 18 controls the playback module 19 to play the right channel audio.

1, 1', 2‧‧‧Symmetrical earphone device 10‧‧‧Body 11‧‧‧Outer earbud ring 111‧‧‧Left half ring 112‧‧‧Right half ring 12‧‧‧Sound opening 13‧‧‧ Back cover 14‧‧‧Extension rod 15‧‧‧First proximity sensor 15S‧‧‧First detection signal 16‧‧‧Second proximity sensor 16S‧‧‧Second detection signal 17‧‧ ‧Communication module 18‧‧‧Processing module 19‧‧‧Playing module 21‧‧‧First photosensitive element 22‧‧‧Second photosensitive element A‧‧‧Sound source signal S‧‧‧Central symmetry plane C‧‧ ‧Central position CL‧‧‧Central axis V‧‧‧Vertical centerline L1‧‧‧First connection L2‧‧‧Second connection θ1‧‧‧First included angle θ2‧‧‧Second included angle E‧‧‧ Left ear E'‧‧‧right ear E1‧‧‧concha cavity E2‧‧‧tragus

[Figure 1] is a perspective view of an embodiment of the symmetrical earphone device of the present invention. [Figure 1A] is a partially enlarged perspective view of an embodiment of the symmetrical earphone device of the present invention. [Figure 2] is a plan view of an embodiment of the symmetrical earphone device of the present invention. [Figure 3] is a device block diagram of an embodiment of the symmetrical earphone device of the present invention. [Fig. 4] is a schematic diagram of the arrangement of an embodiment of the symmetrical earphone device of the present invention. [Figure 5] is a schematic diagram of the left ear wearing of an embodiment of the symmetrical earphone device of the present invention. [Figure 6] is a schematic diagram of the right ear wearing of an embodiment of the symmetrical earphone device of the present invention. [Figure 7] is a plan view of another embodiment of the symmetrical earphone device of the present invention. [Fig. 8] is a device block diagram of another embodiment of the symmetrical earphone device of the present invention.

1, 2‧‧‧Symmetrical earphone device

10‧‧‧Ontology

11‧‧‧Outer earplug ring

111‧‧‧Left half ring

112‧‧‧Right half ring

13‧‧‧Back cover

14‧‧‧Extension Rod

15‧‧‧The first proximity sensor

16‧‧‧Second Proximity Sensor

17‧‧‧Communication Module

S‧‧‧Central symmetry plane

Claims (9)

A symmetrical earphone device for receiving an audio source signal from the outside, the audio source signal including a left channel audio and a right channel audio, the symmetrical earphone device includes: a body, including an outer earplug ring, the outer The earplug ring includes a central symmetry plane, a left half ring and a right half ring. The central symmetry plane separates the left half ring and the right half ring on two opposite sides. The left half ring and the right half ring are symmetrical about the center. The surfaces are symmetrical to each other; a first proximity sensor is arranged on the left half of the outer earplug ring, the first proximity sensor detects and correspondingly outputs a first detection signal; a second proximity sensor The device is arranged on the right half of the outer earplug ring, the second proximity sensor detects and correspondingly outputs a second detection signal; a communication module, which receives the external audio signal; a playback module, It includes a single speaker, the speaker is arranged in the body, and is electrically connected to the communication module; and a processing module is electrically connected to the first proximity sensor, the second proximity sensor, and the communication module Group and the speaker, the processing module selectively controls the speaker to play the left channel audio or selectively controls the speaker to play the right channel audio according to the first detection signal and the second detection signal ; Wherein the outer earplug ring has a center position and a vertical centerline passing through the center position, the vertical centerline is perpendicular to the axial direction of the outer earplug ring, and the center position and the vertical centerline are both located on the central symmetry plane Above, there is a first included angle between a first line from the first proximity sensor to the center position and the vertical center line, and the second proximity sensor to There is a second included angle between a second line at the center position and the vertical center line, the first included angle is between -75°~-85°, and the second included angle is between 75°~85° between. The symmetrical earphone device according to claim 1, wherein the first proximity sensor and the second proximity sensor are symmetrically arranged according to the central symmetry plane. The symmetrical earphone device according to claim 1, wherein the processing module controls the speaker to play the left channel audio according to when the intensity of the first detection signal is less than the intensity of the second detection signal, and the processing module The group controls the speaker to play the right channel audio according to when the intensity of the first detection signal is greater than the intensity of the second detection signal. The symmetrical earphone device according to claim 1, further comprising a photosensitive element disposed on the left half ring of the outer earplug ring and adjacent to the first proximity sensor, and the processing module is electrically connected to the photosensitive element And further selectively controlling the speaker to play the left channel audio or selectively controlling the speaker to play the right channel audio according to a sensing result of the photosensitive element. The symmetrical earphone device according to claim 4, wherein the sensing result includes that the photosensitive element receives an external light signal or the photosensitive element does not receive the external light signal, and the processing module does not receive the external light signal according to the photosensitive element When the external light signal, the speaker is controlled to play the left channel audio, and the processing module controls the speaker to play the right channel audio when the photosensitive element receives the external light signal. The symmetrical earphone device according to claim 5, further comprising another photosensitive element disposed on the right half ring of the outer earplug ring and adjacent to the second proximity sensor, and the processing module is electrically connected to the other A photosensitive element, and according to another sense of the other photosensitive element The measurement result selectively controls the speaker to play the left channel audio or selectively controls the speaker to play the right channel audio. The symmetrical earphone device according to claim 6, wherein the other sensing result includes that the other photosensitive element receives another external light signal or the other photosensitive element does not receive the other external light signal, the processing The module further controls the speaker to play the left channel audio according to when the other photosensitive element receives the other external light signal, and the processing module further controls the speaker to play the left channel audio according to when the other photosensitive element does not receive the other external light signal To control the speaker to play the right channel audio. The symmetrical earphone device according to claim 1, wherein the first proximity sensor and the second proximity sensor are both an infrared proximity sensor. The symmetrical earphone device according to claim 1, wherein the body further includes a sound outlet, a back cover and an extension rod, and the sound outlet and the back cover are located axially opposite to the outer earplug ring. At the end, the extension rod extends from the rear cover body and is symmetrical with respect to the central symmetry plane.

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