Headphone Module

Abstract

This invention provides an earphone module, including a housing, a circuit board, a feed conductor, a first ground conductor, and a second ground conductor. The housing includes an insulating shell and a metal ring connected to the insulating shell. The metal ring serves as an antenna and includes a feed end, a first ground end, a second ground end, and a slit that breaks the metal ring. The slit is located between the feed end and the first ground end, and the second ground end is located between the feed end and the slit. The circuit board is located inside the insulating shell, and the circuit board and the metal ring form a slot. The feed conductor connects the feed end and the circuit board. The first ground conductor connects the first ground end and the circuit board. The second ground conductor connects the second ground end and the circuit board. The earphone module provided by this invention utilizes a metal ring as a magnetic antenna structure, which, because it is less susceptible to human influence on its resonant mode, has better antenna efficiency.

Description

Technical Field

[0001] This invention relates to an earphone module, and more particularly to an earphone module with a slot antenna. Background Technology

[0002] Bluetooth headsets typically use an electric antenna architecture. A certain distance needs to be maintained between the touchpad and the electric antenna to reduce electrical coupling, but this limits the touchpad's area. Furthermore, because the electric antenna architecture has an open circuit at its end, the current is small and the electric field is strong, making it susceptible to frequency band shifts caused by the human body's dielectric properties, thus affecting antenna efficiency. Summary of the Invention

[0003] This invention provides an earphone module that uses a metal ring as a magnetic antenna structure. Because its resonant mode is not easily affected by the human body, it has better antenna efficiency.

[0004] An earphone module of the present invention includes a housing, a circuit board, a feed conductor, a first ground conductor, and a second ground conductor. The housing includes an insulating shell and a metal ring connected to the insulating shell, wherein the metal ring serves as an antenna and includes a feed end, a first ground end, a second ground end, and a slit that breaks the metal ring. The slit is located between the feed end and the first ground end, and the second ground end is located between the feed end and the slit. The circuit board is located inside the insulating shell, and the circuit board and the metal ring form a slot. The feed conductor connects the feed end and the circuit board. The first ground conductor connects the first ground end and the circuit board. The second ground conductor connects the second ground end and the circuit board.

[0005] In one embodiment of the present invention, the above-mentioned feed end along the metal ring to the first ground end is the resonant path of the antenna, the resonant path causes the slot to couple out of the frequency band, and the length of the resonant path is 0.5 times the wavelength of the frequency band.

[0006] In one embodiment of the present invention, the above-mentioned headphone module further includes a flexible circuit board located inside the insulating housing and connected to the circuit board, wherein the projection of the flexible circuit board onto the metal ring overlaps at half of the resonant path along the feed end of the metal ring.

[0007] In one embodiment of the present invention, the above-mentioned headphone module further includes a third grounding conductor, and the metal ring further includes a third grounding terminal located between and close to the first grounding terminal and the slit. The third grounding conductor is connected to the third grounding terminal and the circuit board.

[0008] In one embodiment of the present invention, the feed end along the metal ring to the first ground end serves as a low-pass filter, and the feed end along the metal ring to the second ground end serves as a high-pass filter.

[0009] In one embodiment of the present invention, the second grounding conductor described above is located away from the feed end and the slit.

[0010] In one embodiment of the present invention, the slit is between 0.2 mm and 0.5 mm.

[0011] In one embodiment of the present invention, the aforementioned metal ring is located above the circuit board.

[0012] In one embodiment of the present invention, the above-mentioned headphone module further includes a flexible circuit board located inside the insulating housing and connected to the circuit board, and the distance between the metal ring and the flexible circuit board is at least greater than 1 mm.

[0013] In one embodiment of the present invention, the above-mentioned headphone module further includes a touch panel, which is exposed on the outer shell, and a metal ring is located below the touch panel or flush with the touch panel.

[0014] In one embodiment of the present invention, when the earphone module is placed in a person's ear, the feed end is close to the antihelix of the ear and away from the earlobe, and the first ground end is close to the earlobe of the ear.

[0015] In one embodiment of the present invention, when the earphone module is placed in the ear, the circuit board is located between the metal ring and the external auditory canal of the ear, so that the antenna generates an antenna polarization direction that enters the external auditory canal.

[0016] Based on the above, the outer shell of the headphone module of the present invention includes an insulating shell and a metal ring connected to the insulating shell. The metal ring serves as an antenna and includes a feed end, a first ground end, a second ground end, and a slit that breaks the metal ring. The slit is located between the feed end and the first ground end, and the second ground end is located between the feed end and the slit. A circuit board is located inside the insulating shell, and the circuit board and the metal ring form a slot. A feed conductor connects the feed end and the circuit board. A first ground conductor connects the first ground end and the circuit board. A second ground conductor connects the second ground end and the circuit board. With the above design, the headphone module of the present invention has a magnetic antenna structure, which is less susceptible to the influence of the human body on the resonant mode, resulting in better antenna efficiency. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the appearance of an earphone module according to an embodiment of the present invention;

[0018] Figure 2A yes Figure 1 A perspective view of the headphone module;

[0019] Figure 2B yes Figure 1 The equivalent circuit diagram of the slot of the headphone module;

[0020] Figure 2C yes Figure 1 Smith chart of the antenna for the headphone module;

[0021] Figure 3A and Figure 3B yes Figure 1 A partial schematic diagram of the metal ring, circuit board, and flexible circuit board of the headphone module;

[0022] Figure 4A and Figure 4B They are Figure 3A and Figure 3B Efficiency-frequency diagram of the headphone module;

[0023] Figure 5 It is Figure 1 A diagram illustrating the placement of the earphone module inside the ear;

[0024] Figure 6 yes Figure 5 A perspective view of the metal ring, circuit board, and flexible circuit board of the headphone module;

[0025] Figure 7A and Figure 7B They are Figure 5 Efficiency-frequency relationship of the headphone module in BH state and BHHR state.

[0026] Explanation of reference numerals in the attached figures

[0027] C: Surface current;

[0028] C S1 The equivalent capacitance between the metal ring and the circuit board at the location corresponding to slot H1;

[0029] C S1’ The equivalent capacitance between the metal ring and the circuit board at the corresponding adjusted slot H1 position after the first grounding conductor moves.

[0030] C S2 The equivalent capacitance between the metal ring and the circuit board at the location corresponding to slot H2;

[0031] C S3 The equivalent capacitance between the metal ring and the circuit board at the location corresponding to slot H3;

[0032] G S1 The location of the first grounding conductor;

[0033] G S1’ The new location of the first grounding conductor after it has been moved;

[0034] G S2 Location of the second grounding conductor;

[0035] G S3 Location of the third grounding conductor;

[0036] L S1 The equivalent inductance of slot H1 on the metal ring;

[0037] L S1’ The equivalent inductance of slot H1 on the metal ring after the first grounding conductor moves;

[0038] L S2 The equivalent inductance of slot H2 on the metal ring;

[0039] L S2’ The equivalent inductance of the metal ring at the open-circuit remnant;

[0040] L S3 The equivalent inductance of slot H3 on the metal ring;

[0041] H1, H2, H3: Slots;

[0042] S: narrow slit;

[0043] 10: Human ear;

[0044] 11: Antihelix;

[0045] 12: Earlobes;

[0046] 13: Earlobes;

[0047] 20: Headphone module;

[0048] 30: Outer shell;

[0049] 40: Insulating housing;

[0050] 50: Circuit board;

[0051] 52: Feed-in conductive element;

[0052] 54: First grounding conductor;

[0053] 56: Second grounding conductor;

[0054] 58: Third grounding conductor;

[0055] 60: Flexible circuit board;

[0056] 70: Touchpad;

[0057] 100: Metal ring;

[0058] 102: Remaining sections of the road;

[0059] 104: Zero current point;

[0060] 110: Feed input end;

[0061] 120: First grounding terminal;

[0062] 130: Second grounding terminal;

[0063] 140: Third grounding terminal. Detailed Implementation

[0064] Reference will now be made in detail to exemplary embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same component symbols are used in the drawings and description to denote the same or similar parts.

[0065] Figure 1 This is a schematic diagram of the appearance of an earphone module according to an embodiment of the present invention. Figure 2A yes Figure 1 A perspective view of the headphone module. Please refer to [link / reference]. Figure 1 and Figure 2A The headphone module 20 of this embodiment includes a housing 30, which includes an insulating shell 40 and a metal ring 100 connected to the insulating shell 40. The insulating shell 40 is made of materials such as plastic, but is not limited thereto.

[0066] In this embodiment, the metal ring 100 serves as an antenna. For example... Figure 2A As shown, the metal ring 100 includes a feed end 110, a first ground end 120, a second ground end 130, and a slit S that breaks the metal ring 100. The slit S is located between the feed end 110 and the first ground end 120 in a clockwise direction, and the second ground end 130 is located between the feed end 110 and the slit S in a clockwise direction. The width of the slit S is between 0.2 mm and 0.5 mm to maintain a relatively complete appearance design while allowing sufficient manufacturing tolerances.

[0067] The headphone module 20 in this embodiment also includes a circuit board 50, a feed conductor 52, a first ground conductor 54, and a second ground conductor 56. The circuit board 50 is located inside the insulating housing 40. The feed conductor 52, the first ground conductor 54, and the second ground conductor 56 respectively connect the feed terminal 110, the first ground terminal 120, and the second ground terminal 130 to the circuit board 50.

[0068] In this embodiment, the resonant path of the antenna extends counterclockwise from the feed terminal 110 along the metal ring 100 to the first ground terminal 120. The length of the resonant path is 0.5 times the wavelength of the frequency band coupled out by the antenna. The frequency band coupled out by the antenna is, for example, the 2.4 GHz Bluetooth band, but the frequency band is not limited to this. The length of the resonant path is between 34 mm and 36 mm, and a 2.4 GHz operating frequency band can be coupled out.

[0069] Furthermore, in this embodiment, the metal ring 100 may optionally include a third grounding terminal 140, located between and close to the first grounding terminal 120 and the slit S, with the slit S located between the second grounding terminal 130 and the third grounding terminal 140. The headphone module 20 in this embodiment further includes a third grounding conductor 58, which connects the third grounding terminal 140 and the circuit board 50.

[0070] Slots H1, H2, and H3 exist between the metal ring 100 and the circuit board 50. Specifically, slot H1 exists between the metal ring 100 and the circuit board 50 in the section from the feed end 110 counterclockwise to the first ground end 120. Slot H2 exists between the metal ring 100 and the circuit board 50 in the section from the feed end 110 clockwise to the second ground end 130. Slot H3 exists between the metal ring 100 and the circuit board 50 in the section between the first ground end 120 and the third ground end 140.

[0071] In this embodiment, the slots H1, H2, and H3 between the metal ring 100 and the circuit board 50 can be filled with plastic and contain air. Considering that the relative permittivity of air is 1 and the relative permittivity of plastic is 2.7 to 3.0, the length of the path from the feed end 110 counterclockwise along the metal ring 100, through the first ground end 120 and the third ground end 140 to the slit S is between 45 mm and 50 mm, for example, 47 mm. This path is connected to the ground plane of the circuit board 50 through the third ground end 140, which helps to couple out the 2.4 GHz operating frequency band.

[0072] It is worth mentioning that, in this embodiment, the feed terminal 110, moving counterclockwise along the metal ring 100 to the first ground terminal 120, can also serve as a low-pass filter. That is, the feed terminal 110, moving counterclockwise along the metal ring 100 to the first ground terminal 120, serves as a resonant path, allowing the slot to couple out a 2.4GHz frequency band, and simultaneously acts as a low-pass filter.

[0073] Furthermore, in this embodiment, the feed terminal 110, moving clockwise along the metal ring 100 to the second ground terminal 130, can serve as a high-pass filter. In addition, the second grounding conductor 56, connected to the second ground terminal 130, is positioned away from the feed terminal 110 and the slit S in the section between the feed terminal 110 and the slit S. This design allows the antenna system to achieve optimized impedance matching.

[0074] Furthermore, in this embodiment, the first grounding conductor 54, the second grounding conductor 56, the third grounding conductor 58, the feed conductor 52, the metal ring 100, and the outer shell 30 can be manufactured as a single unit by injection molding or laser direct molding (LDS). Of course, the molding method of the first grounding conductor 54, the second grounding conductor 56, the third grounding conductor 58, and the metal ring 100 is not limited to this.

[0075] like Figure 2A As shown, in this embodiment, the headphone module 20 further includes a flexible circuit board 60, located inside the insulating housing 40 and connected to the circuit board 50. The projection of the flexible circuit board 60 onto the metal ring 100 overlaps with the feed end 110 at half of the resonant path of the metal ring 100.

[0076] Specifically, the portion of the flexible circuit board 60 closest to the metal ring 100 is located at the midpoint of the counter-clockwise resonant path from the feed end 110 to the first grounding conductor 54. This location is the current zero point 104 because the phases of the electromagnetic waves cancel each other out. By placing the flexible circuit board 60 close to the current zero point 104 on the metal ring 100, the headphone module 20 can reduce electrical coupling and parasitic current between the metal ring 100 and the flexible circuit board 60, while also facilitating impedance matching of the antenna, thus ensuring good antenna efficiency.

[0077] Conventional electric antenna architectures housed within a casing suffer from several drawbacks. Because the antenna is open-circuited at its ends, the current is low and the electric field is strong, making the radiated energy easily absorbed by external dielectrics, such as the human body, causing a shift in the antenna's operating frequency band. Furthermore, in headphone modules with electric antenna architectures, the main substrate requires an antenna clearance area along the antenna path, preventing the main substrate's space from being fully utilized for circuit layout.

[0078] Compared to conventional electric antenna architectures, the metal ring 100 in this embodiment serves as a magnetic antenna architecture. Through the forced boundary formed by the feed end 110, the first grounding conductor 54, the second grounding conductor 56, and the third grounding conductor 58, impedance matching can be adjusted according to the operating frequency band. Furthermore, the magnetic antenna is less susceptible to human influence on its resonant mode, resulting in better antenna efficiency. In addition, because the antenna in this embodiment incorporates a built-in Bluetooth antenna matching circuit through the aforementioned low-pass filter, high-pass filter, and impedance matching design, the headphone module 20 in this embodiment does not require an antenna clearance area on the circuit board 50, thus fully utilizing the space on the circuit board 50.

[0079] In addition, such as Figure 1 As shown, the headphone module 20 is a touch-sensitive headphone module, and the headphone module 20 further includes a touchpad 70, which is externally mounted on the housing 30. Figure 2A As shown, the metal ring 100 is located above the circuit board 50 and optionally on the touchpad 70. Figure 1 It is located below or flush with the touchpad 70. That is, the metal ring is located between the touchpad 70 and the circuit board 50.

[0080] In conventional electric antennas, a relative distance must be maintained between the electric antenna and the touchpad to reduce electrical coupling between them. This limits the area of ​​the touchpad to prevent it from getting too close to the electric antenna (e.g., at the edge). In this embodiment, the headphone module 20 uses a magnetic antenna architecture, so the touchpad 70 of the headphone module 20 does not need to be too far from the edge of the metal ring 100. Therefore, a larger touchpad 70 can be used, making touch operation more convenient.

[0081] Figure 2B yes Figure 1 The equivalent circuit diagram of the headphone module slots. Please refer to [link / reference]. Figure 2B First of all, let me explain Figure 2B The symbol in C S1 This refers to the equivalent capacitance between the metal ring 100 at the location corresponding to slot H1 and the circuit board 50. C S1’ This refers to the equivalent capacitance between the metal ring 100 and the circuit board 50 at the corresponding adjusted slot H1 location after the first grounding conductor 54 is moved. S2 This refers to the equivalent capacitance between the metal ring 100 at the location corresponding to slot H2 and the circuit board 50. C S3 This refers to the equivalent capacitance between the metal ring 100 at the corresponding slot H3 and the circuit board 50.

[0082] G S1 This refers to the location of the first grounding conductor 54. G S1’ This refers to the new position of the first grounding conductor 54 after it has been moved. S2 This refers to the location of the second grounding conductor 56. G S3 This refers to the location of the third grounding conductor 58.

[0083] L S1 This refers to the equivalent inductance of slot H1 on metal ring 100. S1’ This refers to the equivalent inductance of the slot H1 on the metal ring 100 after the first grounding conductor 54 has moved. S2 This refers to the equivalent inductance of slot H2 on metal ring 100. S2’ This refers to the equivalent inductance of the metal ring 100 at the open-circuit residual section 102. L S3 The equivalent inductance of slot H3 on the metal ring is 100. Figure 2B The arrow in the diagram indicates the direction of the surface current C.

[0084] exist Figure 2B In the middle, when the first grounding conductor 54 is moved (meaning the setting position G of the first grounding conductor 54 is changed), S1 Adjust to G S1When the slot H1 is 36 mm long, the impedance adjustment range of the slot H1 can be introduced. At this time, the length of the slot H1 is 36 mm, and the impedance adjustment range of the slot H1 can fall within 2 mm. This design makes the length of the resonant path between 34 mm and 36 mm, and allows the slot to couple out the 2.4 GHz operating frequency band.

[0085] Furthermore, due to the setting position G of slot H2 and the second grounding conductor 56 S2 Regarding this, the designer can adjust the setting position G of the second grounding conductor 56. S2 The equivalent parallel inductance value is adjusted to compensate for the capacitance of slot H1 (including the impedance adjustment section of slot H1). The open-circuit remnant 102 can serve as reserved space for inductance compensation and also maintain the appearance integrity of the metal ring 100.

[0086] Additionally, slot H3 is located at position G of the first grounding conductor 54. S1 or G S1’ Position G of the third grounding conductor 58 S3 Between them, slot H3 can reserve space for the impedance adjustment section of slot H1, and is also part of the antenna radiation structure.

[0087] Therefore, the first grounding conductor 54 is positioned at position G. S1 An equivalent adjustable low-pass filter circuit can be derived, and the setting position G of the second grounding conductor 56 is... S2 It can be equivalent to an adjustable high-pass filter circuit, so that the antenna of the headphone module 20 has a bandpass matching circuit for the Bluetooth band. Figure 2C yes Figure 1 The Smith chart of the headphone module in the Bluetooth band allows for good impedance matching of the antenna system.

[0088] Figure 3A and Figure 3B This is a partial schematic diagram of the metal ring, circuit board, and flexible circuit board of the headphone module. Please refer to [link / reference]. Figure 3A In this embodiment, the metal ring 100 is located below the touchpad 70 (e.g., Figure 3A As shown, the width of metal ring 100 is 2.35 mm. Please refer to [link / reference]. Figure 3B The width of the metal ring 100 can be adjusted in the direction (above) of the touchpad 70 so that the metal ring 100 is flush with the touchpad 70 (e.g., Figure 3B (As shown). The width of the metal ring 100 is 3.35 mm. Of course, the width of the metal ring 100 is not limited to the above.

[0089] Figure 4A and Figure 4B They are Figure 3A and Figure 3B The efficiency-frequency diagram of the headphone module. Please refer to [link / reference]. Figure 4A In the 2.4GHz operating frequency band, when the width of the metal ring 100 is 2.35 mm ( Figure 3A At this point, the antenna efficiency is -8.59 dB and the radiation efficiency is -8.45 dB, demonstrating good performance. Please refer to [link / reference]. Figure 4B In the 2.4GHz operating frequency band, when the width of the metal ring 100 is 3.35 mm ( Figure 3B When the antenna efficiency is -7.94dB and the radiation efficiency is -7.89dB, it also has good performance.

[0090] Furthermore, if the metal ring 100 is widened towards the flexible circuit board 60, although the current zero point 104 helps to reduce the coupling effect caused by the small spacing between the metal ring 100 and the flexible circuit board 60, the distance between the metal ring 100 and the flexible circuit board 60 should still be at least greater than 1 mm in order to maintain good impedance performance.

[0091] In general, in this embodiment, the path length of the antenna feed end 110 from the metal ring 100 to the first grounding conductor 54 is between 34 mm and 36 mm, which is half the wavelength of the 2.4 GHz frequency, and thus couples out a 2.4 GHz signal.

[0092] Furthermore, the headphone module 20 facilitates better antenna coupling of the 2.4 GHz signal through the following means: First, considering the relative permittivity of air and plastic, the path length of the feed terminal 110 counterclockwise along the metal ring 100 to the slit S is between 45 mm and 50 mm. The third grounding conductor 58 is positioned near the slit S in this path, thereby grounding the feed terminal 110 counterclockwise along the metal ring 100 to the third grounding conductor 58.

[0093] Second, the section between the feed end 110 and the slit S is an open circuit remnant 102. The second grounding conductor 56 is placed in the section between the feed end 110 and the slit S at a position away from the feed end 110 and the slit S, so as to achieve a better impedance matching effect while being able to couple out 2.4GHz.

[0094] Third, the flexible circuit board 60 is located at halfway along the counterclockwise path from the feed end 110 along the metal ring 100 to the first grounding conductor 54, coinciding with the current zero point 104, which reduces the electrical coupling between the flexible circuit board 60 and the metal ring 100, allowing the magnetic antenna to have good system impedance matching.

[0095] Figure 5 It is Figure 1 This is a diagram illustrating how the earphone module is placed inside the ear. It should be noted that... Figure 5The headphone module 20 removes the touchpad 70 to clearly show the relative positions of the feed inlet 110, the first grounding conductor 54, the second grounding conductor 56, the third grounding conductor 58, and the human ear 10. (See also...) Figure 5 The human ear 10 includes an antihelix 11 located above the ear canal opening, an earlobe 12 located below the ear canal opening, and an earlobe 13 (also known as a tragus) located between the ear canal opening and the cheek.

[0096] Because the earphone module 20 has a Bluetooth connection with an electronic device (not shown, such as a mobile phone or tablet), taking a mobile phone as an example, the phone may be placed in a pocket or held in the hand for use. In this case, the Bluetooth connection between the earphone module 20 and the electronic device will be blocked by the human body. In this embodiment, when the earphone module 20 is placed in the ear 10, such as Figure 5 As shown, the feed terminal 110 is close to the antihelix 11 of the human ear 10 and away from the earlobe 12, while the first ground terminal 120 is close to the earlobe 13, so that the direction of antenna radiation is towards... Figure 5 The lower right corner (facing the electronic device) of the headphone module 20 allows for good cross-body (cross-body) radiation performance in the Bluetooth connection between the headphone module 20 and the electronic device.

[0097] Figure 6 yes Figure 5 A perspective view of the metal ring, circuit board, and flexible circuit board of the headphone module. Please refer to [link / reference]. Figure 6 The headphone module 20 is placed in the ear 10 ( Figure 5 When the circuit board 50 is inside the metal ring 100 and the external auditory canal of the human ear 10, the circuit board 50 is located between the metal ring 100 and the external auditory canal of the human ear 10. Figure 5 , corresponding to Figure 6 Between the right and the left sides, so that the antenna generates an antenna polarization direction that enters the external auditory canal (to the right).

[0098] Specifically, the metal ring 100 of the headphone module 20 and the circuit board 50 are positively and negatively charged, respectively. The resulting antenna polarization direction is from the positively charged direction to the negatively charged direction, and the antenna polarization direction is perpendicular to the circuit board 50. Therefore, when the headphone module 20 is placed inside the ear 10 ( Figure 6 When the human ear (not shown, located on the right side of the headphone module) is in the ear, the antenna polarization direction generated by the antenna is directed from the metal ring 100 to the circuit board 50, and finally into the external auditory canal. This arrangement reduces the absorption or cancellation of energy by other structures of the external ear, such as the ear bones, thereby reducing the influence of the human ear 10 on the antenna signal. In addition, because the current distribution of the magnetic antenna architecture is limited by the forced boundary formed by the feed conductor 52 and the first ground conductor 54, the frequency band shift caused by individual differences in wearing conditions can be reduced, which helps to optimize the radiation performance during wear.

[0099] Figure 7A and Figure 7B They are Figure 5 The efficiency-frequency relationship of the headphone module in BH state and BHHR state is shown in the graph. Specifically, Figure 7A Antenna efficiency-frequency diagram when the headphone module is placed inside the right ear (BH, i.e., the headphone module is placed in the right ear). Figure 7B Antenna efficiency-frequency diagram when the headphone module is placed inside the right ear and the right hand is placed on the headphone module (BHHR, i.e., the state of touching the headphone module placed inside the right ear with the right hand).

[0100] Please see Figure 7A and 7B In this embodiment, when the earphone module 20 is placed in the right ear and when the earphone module 20 is touched by the right hand while placed in the right ear, the radiation efficiency in the 2.4GHz band is -7.66dB and -7.53dB respectively, both showing good performance. Furthermore, the radiation efficiency is not significantly different between the two, indicating that even if a human dielectric (e.g., a finger) touches the earphone module 20 of this embodiment, the antenna radiation efficiency will not be affected. Moreover, actual measurements show that compared to conventional antenna modules, the antenna radiation efficiency of the earphone module 20 in this embodiment is improved by at least 1.59dB and 2.67dB in different states, respectively, demonstrating superior performance.

[0101] In summary, the outer shell of the headphone module of the present invention includes an insulating shell and a metal ring connected to the insulating shell. The metal ring serves as an antenna and includes a feed end, a first ground end, a second ground end, and a slit that breaks the metal ring. The slit is located between the feed end and the first ground end, and the second ground end is located between the feed end and the slit. The circuit board is located inside the insulating shell, and the circuit board and the metal ring form a slot. A feed conductor connects the feed end and the circuit board. A first ground conductor connects the first ground end and the circuit board. A second ground conductor connects the second ground end and the circuit board. With the above design, the headphone module of the present invention has a magnetic antenna structure, which is less susceptible to the influence of the human body on the resonant mode, and thus has better antenna efficiency. The headphone module of the present invention also does not require setting an antenna clearance area on the circuit board to improve antenna performance, and can make full use of the space on the circuit board.

[0102] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. An earphone module, characterized in that, include: The housing includes an insulating shell and a metal ring connected to the insulating shell, wherein the metal ring serves as an antenna, and the metal ring includes a feed end, a first ground end, a second ground end, and a slit that breaks the metal ring, the slit being located between the feed end and the first ground end, the second ground end being located between the feed end and the slit, wherein the feed end along the metal ring to the first ground end forms the resonant path of the antenna; A circuit board is located inside the insulating housing, and the circuit board forms a slot with the metal ring; A feed conductor is provided to connect the feed end and the circuit board. The first grounding conductor connects the first grounding terminal and the circuit board; The second grounding conductor connects the second grounding terminal and the circuit board. as well as A flexible circuit board, located within the insulating housing and connected to the circuit board, the projection of the flexible circuit board onto the metal ring overlaps at the feed end along the metal ring at halfway along the resonant path.

2. The headphone module according to claim 1, characterized in that, The resonant path couples the slot into a frequency band, and the length of the resonant path is 0.5 times the wavelength of the frequency band.

3. The headphone module according to claim 1, characterized in that, It also includes a third grounding conductor, and the metal ring further includes a third grounding terminal located between and close to the first grounding terminal and the slit, the third grounding conductor connecting the third grounding terminal and the circuit board.

4. The headphone module according to claim 3, characterized in that, The feed end along the metal ring to the first ground terminal serves as a low-pass filter, and the feed end along the metal ring to the second ground terminal serves as a high-pass filter.

5. The headphone module according to claim 1, characterized in that, The second grounding conductor is located away from the feed end and the slit.

6. The headphone module according to claim 1, characterized in that, The slit is between 0.2 mm and 0.5 mm.

7. The headphone module according to claim 1, characterized in that, The metal ring is located above the circuit board.

8. The headphone module according to claim 1, characterized in that, It also includes a flexible circuit board, located inside the insulating housing and connected to the circuit board, wherein the distance between the metal ring and the flexible circuit board is at least greater than 1 millimeter.

9. The headphone module according to claim 1, characterized in that, It also includes a touchpad, which is exposed on the housing, and the metal ring is located below or flush with the touchpad.

10. The headphone module according to claim 1, characterized in that, When the earphone module is placed inside a person's ear, the feed end is close to the antihelix of the ear and away from the earlobe, and the first ground end is close to the earlobe of the ear.

11. The headphone module according to claim 1, characterized in that, When the earphone module is placed inside a person's ear, the circuit board is located between the metal ring and the external auditory canal of the person's ear, so that the antenna generates an antenna polarization direction that enters the external auditory canal.

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