An electret microphone

Abstract

The utility model provides a kind of electret microphone, belong to acoustics field, including metal shell, diaphragm assembly is equipped in the metal shell, circuit board, the cavity ring is also equipped in the metal shell, one end of the cavity ring is equipped with back electrode plate, the back electrode plate is located between the diaphragm assembly and the cavity ring, the circuit board is located between the metal shell and the cavity ring, the sidewall of the cavity ring is equipped with shell fragment, one end of the shell fragment extends to the circuit board and is contacted with the circuit board, the other end of the shell fragment extends to the back electrode plate and is contacted with the back electrode plate;The shell fragment replaces original polar ring guide intercommunication electrode plate and FET Drain end, the parasitic capacitance generated in microphone interior reduces, the performance (sensitivity, signal-to-noise ratio, high frequency response) of microphone is improved;The setting of the shell fragment has realized the conduction of back electrode plate and circuit board, no longer use polar cavity, both improve assembly efficiency and reduce material and artificial cost.

Description

Technical Field

[0001] This utility model relates to an electret microphone. Background Technology

[0002] The core of an electret microphone is the capacitor structure formed by the diaphragm and the electrode plates. Because the internal structure of the microphone generates parasitic capacitance, which is connected in parallel with the microphone's inherent capacitance, it creates a voltage divider effect, resulting in a decrease in the output signal voltage, a decrease in the microphone's sensitivity, and a deterioration in the signal-to-noise ratio. Furthermore, since the parasitic capacitance and the resistor in the circuit form a low-pass filter, if the parasitic capacitance is too large, high-frequency signals will be filtered out, thus limiting the microphone's high-frequency response.

[0003] The two most commonly used structures for electret microphones are shown in the attached figure. Figure 1 and attached Figure 2 As shown: Appendix Figure 1 The structure has two types of parasitic capacitance: the parasitic capacitance between the cavity and the circuit board, and the parasitic capacitance between the shell and the cavity. Appendix Figure 2 The structure has a parasitic capacitance, which is the parasitic capacitance between the outer shell and the electrode ring. Utility Model Content

[0004] The purpose of this invention is to overcome the shortcomings of the above-mentioned traditional technologies and provide an electret microphone.

[0005] The purpose of this utility model is achieved through the following technical measures: an electret microphone, comprising a metal housing, a diaphragm assembly disposed within the metal housing, a circuit board disposed at the open end of the metal housing, a cavity ring disposed within the metal housing, a back electrode plate disposed at one end of the cavity ring, the back electrode plate being located between the diaphragm assembly and the cavity ring, and the circuit board being located between the metal housing and the cavity ring, characterized in that: a spring is disposed on the side wall of the cavity ring, one end of the spring extends to the circuit board and contacts the circuit board, and the other end of the spring extends to the back electrode plate and contacts the back electrode plate.

[0006] As an improvement, the spring includes a spring body, which is injection molded into the side wall of the cavity ring. One end of the spring body is provided with a first long cantilever that extends obliquely out of the cavity ring, and the other end of the spring body is provided with a second long cantilever that extends obliquely out of the cavity ring. The first long cantilever and the second long cantilever are arranged opposite to each other. In the free state, the highest end of the first long cantilever is higher than the upper end surface of the cavity ring, and the lowest end of the second long cantilever is lower than the lower end surface of the cavity ring where the back electrode plate is placed.

[0007] As a further improvement, the free ends of the first long cantilever are all bent, and a raised first contact point is provided on the contact surface at the bend, and the first contact point contacts the circuit board.

[0008] As a further improvement, the free ends of the second long cantilever are all bent, and a raised second contact point is provided on the contact surface at the bend, the second contact point contacting the back electrode plate.

[0009] As a further improvement, the spring body is provided with at least one through hole.

[0010] As a further improvement, the spring is a copper spring or a copper alloy spring.

[0011] As a further improvement, the cavity ring includes a cavity ring body, which is a hollow ring.

[0012] As a further improvement, the cavity ring body is provided with a cavity partition, which is arranged perpendicularly to the cavity ring body.

[0013] As a further improvement, the thickness of the cross-section of the cavity ring body below the cavity partition is greater than the thickness above the cavity partition.

[0014] As a further improvement, the cavity partition is provided with damping holes.

[0015] Due to the adoption of the above technical solution, the advantages of this utility model compared with the prior art are: First: The spring replaces the original polar ring (polar cavity) to conduct between the electrode plate and the FET Drain terminal, reducing the parasitic capacitance generated inside the microphone and improving the microphone's performance (sensitivity, signal-to-noise ratio, high-frequency response); Second: The setting of the spring has enabled the back electrode plate and the circuit board to conduct, eliminating the need for electrode cavities (electrode rings), which improves assembly efficiency and reduces material and labor costs.

[0016] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0017] Appendix Figure 1 This is a structural schematic diagram of the existing technical solution 1; Appendix Figure 2 This is a structural schematic diagram of the existing technical solution two; Appendix Figure 3 This is a structural schematic diagram of Embodiment 1; Appendix Figure 4 This is a partial structural schematic diagram of Embodiment 1; Appendix Figure 5This is a structural schematic diagram of Embodiment 2; Appendix Figure 6 This is a partial structural schematic diagram of Embodiment 2; Appendix Figure 7 This is a schematic diagram of the structure of the spring sheet described in this invention; Appendix Figure 8 It is attached Figure 7 A schematic diagram of the structure from another direction. Detailed Implementation

[0018] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of the present utility model.

[0019] In the description of this utility model, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model and simplifying the description, and are not intended to indicate or imply that the device or component referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model.

[0020] In this utility model, unless otherwise explicitly specified and limited, the terms "installation", "setting", "connection", "fixing", "screw connection", etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components or the interaction between two components. Unless otherwise explicitly limited, those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0021] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0022] Example 1: As shown in the attached document Figure 3Appendix Figure 4 Appendix Figure 7 and attached Figure 8 As shown, an electret microphone includes a metal housing 1, a diaphragm assembly 2 inside the metal housing 1, a circuit board 3 at the open end of the metal housing 1, a FET field-effect transistor 4 and a capacitor and resistor 5 on the circuit board 3, a cavity ring 6 inside the metal housing 1, a back electrode plate 7 at one end of the cavity ring 6, the back electrode plate 7 being located between the diaphragm assembly and the cavity ring 6, and the circuit board 3 being located between the metal housing 1 and the cavity ring 6.

[0023] The cavity ring 6 includes a cavity ring body 61, which is a hollow ring. A spring piece 9 is provided on the side wall of the cavity ring 6. One end of the spring piece extends to the circuit board 3 and contacts the circuit board 3, and the other end of the spring piece extends to the back electrode plate 7 and contacts the back electrode plate 7.

[0024] The spring 8 includes a spring body 81 with two through holes 82. The spring body 81 is injection molded into the side wall of the cavity ring 6. The number of through holes 82 can be adjusted according to the size of the product. The through holes 82 allow for better bonding between the spring body 81 and the side wall of the cavity ring 6 during injection molding. One end of the spring body 81 has a first long cantilever 83 that extends obliquely out of the cavity ring 6, and the other end of the spring body 81 has a second long cantilever 84 that extends obliquely out of the cavity ring 6. The first long cantilever 83 and the second long cantilever 84 are arranged opposite to each other. In the free state, the highest end of the first long cantilever 83 is higher than the upper end face A of the cavity ring 6, and the lowest end of the second long cantilever 84 is lower than the lower end face B of the cavity ring 6 where the back electrode plate 7 is placed. After assembly, the first contact point 85 of the first long cantilever 83 is attached to the circuit board 3, and the second contact point 86 of the second long cantilever 84 is attached to the back electrode plate 7.

[0025] The free ends of the first long cantilever 83 are all bent, and a raised first contact point 85 is provided on the contact surface at the bend. The first contact point 85 contacts the circuit board 3. The free ends of the second long cantilever 84 are all bent, and a raised second contact point 86 is provided on the contact surface at the bend. The second contact point 86 contacts the back electrode plate 7. The arrangement of the first contact point 85 and the second contact point 86 allows the spring 8 to make point contact with the circuit board 3 and the back electrode plate 7. Because the area of ​​the circuit connected to the drain terminal on the circuit board 3 is limited (because the area of ​​the ground terminal circuit needs to be as large as possible to achieve the effect of anti-interference), point contact can avoid the generation of additional parasitic capacitance due to excessively large drain lines.

[0026] The spring 8 is required to have a large stroke and low elasticity, and good conductivity. Therefore, the spring 8 is a copper spring or a copper alloy spring, and its shape is preferably a long cantilever structure, with a bend at each contact end.

[0027] Example 2: As shown in the attached document Figure 5 - Appendix Figure 8 As shown, the structure is the same as that in Embodiment 1, except that: the cavity ring body 61 is also provided with a cavity partition 62, the cavity partition 62 is arranged perpendicularly to the cavity ring body 61, and the cavity ring body 61 and the cavity partition 62 are integrally injection molded.

[0028] The thickness of the cross section of the cavity ring body 61 below the cavity partition 62 is greater than the thickness above the cavity partition 62. This arrangement can better fix the back electrode plate 7. The cavity partition 62 is provided with a damping hole 63 and a damping 64 is provided at the damping hole 63.

[0029] In summary, the spring 8 replaces the original electrode ring 9 (electrode cavity) to conduct between the electrode plate and the FET Drain terminal, reducing the parasitic capacitance generated inside the microphone and improving the microphone's performance (sensitivity, signal-to-noise ratio, high-frequency response). The spring 8 has already achieved the conduction between the back electrode plate 7 and the circuit board 3, eliminating the need for the electrode ring 9 (electrode cavity), which improves assembly efficiency and reduces material and labor costs.

[0030] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. An electret microphone, comprising a metal housing, a diaphragm assembly disposed within the metal housing, a circuit board disposed at the open end of the metal housing, a cavity ring disposed within the metal housing, a back electrode plate disposed at one end of the cavity ring, the back electrode plate being located between the diaphragm assembly and the cavity ring, and the circuit board being located between the metal housing and the cavity ring, characterized in that: A spring is provided on the side wall of the cavity ring. One end of the spring extends to the circuit board and contacts the circuit board, and the other end of the spring extends to the back electrode plate and contacts the back electrode plate.

2. The electret microphone according to claim 1, characterized in that: The spring includes a spring body, which is injection molded into the side wall of the cavity ring. One end of the spring body is provided with a first long cantilever that extends obliquely out of the cavity ring, and the other end of the spring body is provided with a second long cantilever that extends obliquely out of the cavity ring. The first long cantilever and the second long cantilever are arranged opposite to each other. In the free state, the highest end of the first long cantilever is higher than the upper end surface of the cavity ring, and the lowest end of the second long cantilever is lower than the lower end surface of the cavity ring where the back electrode plate is placed.

3. An electret microphone according to claim 2, characterized in that: The free ends of the first long cantilever are all bent, and a raised first contact point is provided on the contact surface at the bend, and the first contact point contacts the circuit board.

4. An electret microphone according to claim 3, characterized in that: The free ends of the second long cantilever are all bent, and a raised second contact point is provided on the contact surface at the bend, and the second contact point contacts the back electrode plate.

5. An electret microphone according to claim 4, characterized in that: The spring body has at least one through hole.

6. An electret microphone according to claim 5, characterized in that: The spring is a copper spring or a copper alloy spring.

7. An electret microphone according to claim 1, characterized in that: The cavity ring includes a cavity ring body, which is a hollow ring-shaped body.

8. An electret microphone according to claim 7, characterized in that: The cavity ring body is provided with a cavity partition, which is arranged perpendicularly to the cavity ring body.

9. An electret microphone according to claim 8, characterized in that: The thickness of the cross-section of the cavity ring body located below the cavity partition is greater than the thickness located above the cavity partition.

10. An electret microphone according to claim 9, characterized in that: The cavity partition is provided with damping holes.

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