CN215187372U - Electret microphone - Google Patents

Abstract

The utility model provides a microphone, including shell, sound electric conversion module and field effect transistor. The sound-electricity conversion module is arranged in the shell and provided with a polar plate; the field effect transistor is arranged in the shell and provided with a grid pin, and the grid pin is directly connected with the polar plate. The utility model discloses an electret microphone, simple structure, low in production cost has good interference killing feature.

Description

Electret microphone

Technical Field

The utility model relates to an audio frequency technical field, in particular to electret microphone.

Background

The electret microphones on the market at present are various in types, and classified according to polarization modes and directivities, the electret microphones can be classified into diaphragm electret types, back-electrode electret types, pressure difference types, pressure intensity types and pressure difference combined electret microphones, and the electret microphones are sound collecting elements widely applied to electronic equipment, can convert sound waves into electric signals, and enable sound to be transmitted through a conductive cable or stored and restored through the electronic equipment. The anti-interference performance is an important parameter for evaluating the quality of an electret microphone product, the electret microphone with poor anti-interference performance is easily triggered and interfered by noise, noise signals without practical significance and noise signals influencing tone quality are transmitted to a subordinate amplifier or a digital identification circuit by mistake, and the electret microphones with strong anti-interference performance are complex in structure, high in process requirement and low in factory yield, so that the electret microphones with strong anti-interference performance are high in production cost and cannot be widely applied to electronic products.

SUMMERY OF THE UTILITY MODEL

The utility model discloses aim at solving one of the technical problem that exists among the prior art at least. Therefore, the utility model provides an electret microphone, simple structure, overall cost is low and have good interference killing feature.

According to the utility model discloses electret microphone, include:

a housing;

the sound-electricity conversion module is arranged in the shell and is provided with a polar plate;

the field effect transistor is arranged in the shell and provided with a grid pin, and the grid pin is directly connected with the polar plate.

According to the utility model discloses electret microphone has following beneficial effect at least:

the utility model discloses an electret microphone includes shell, sound electric conversion module and field effect transistor. The shell is used for accommodating the acoustic-electric conversion module and the field effect tube and protecting the acoustic-electric conversion module and the field effect tube; the sound-electricity conversion module is arranged in the shell and used for converting sound waves into electric signals, the sound-electricity conversion module is provided with a polar plate, and the sound-electricity conversion module transmits the electric signals to the field effect tube through the polar plate; the field effect tube is arranged in the shell and used for realizing impedance transformation and changing the output impedance of the acoustoelectric conversion module, so that an electric signal generated by the acoustoelectric conversion module can be received by a subordinate amplifying circuit or a digital identification circuit, and the field effect tube is provided with a grid pin which is directly connected with the polar plate. Because the grid pin is directly connected with the polar plate, other transmission media do not exist between the polar plate and the field effect tube, the transmission distance is short, the transmission impedance between the polar plate and the field effect tube can be reduced, the reflection and the loss of useful signals are reduced, and the anti-interference capability of the electret microphone is improved. The acoustoelectric conversion module arranged in the shell is close to the field-effect tube, so that a grid pin of the field-effect tube is abutted to a polar plate of the acoustoelectric conversion module, the connection mode is simple, and the acoustoelectric conversion module is easy to install; the sound-electricity conversion module is connected with the field effect tube without a connecting medium, so that the material cost for connection can be saved; therefore, the electret microphone of the utility model can reduce the production cost.

According to some embodiments of the utility model, electret microphone still includes the support, the support set up in the shell, be provided with the fixed slot on the support, field effect transistor set up in the fixed slot.

According to some embodiments of the present invention, the electret microphone further comprises a shielding cylinder, the shielding cylinder is connected to the support, and the shielding cylinder is wound around the circumferential direction of the fixing groove.

According to some embodiments of the utility model, the shell includes the cover body and circuit board, the circuit board with cover body coupling formation holds the chamber, the support with the acoustic-electric conversion module set up in hold the intracavity, the shielding section of thick bamboo with the acoustic-electric conversion module with the circuit board electricity is connected.

According to some embodiments of the present invention, the circuit board is provided with a first conductor, the first conductor is electrically connected to the ground wire of the circuit board, and the shielding cylinder is connected to the first conductor.

According to some embodiments of the utility model, be provided with the second electric conductor on the circuit board, the second electric conductor with the ground wire electricity of circuit board is connected, the cover body with second electric conductor connection.

According to the utility model discloses a some embodiments, be provided with the first hole of drawing forth on the support, be provided with the second on the circuit board and draw forth the hole, the fixed slot with first hole intercommunication of drawing forth, field effect tube still is provided with source electrode pin and drain electrode pin, source electrode pin with drain electrode pin wears to locate first hole of drawing forth with in the second draws forth the hole.

According to some embodiments of the invention, the source pin is electrically connected to the ground line of the circuit board.

According to some embodiments of the utility model, the acoustoelectric conversion module still is provided with vibrating diaphragm and packing ring, the polar plate with the leg joint, the packing ring set up in the vibrating diaphragm with between the polar plate, the packing ring with the vibrating diaphragm with the polar plate is connected, the vibrating diaphragm with cover body electricity is connected.

According to the utility model discloses a some embodiments, the support is provided with the holding tank, the holding tank winds the circumference setting of fixed slot, be provided with damping fin and foam-rubber cushion in the holding tank, the tank bottom of holding tank the damping fin the foam-rubber cushion with the circuit board connects gradually.

Additional aspects and advantages of the invention will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the invention.

Drawings

The above and/or additional aspects and advantages of the present invention will become apparent and readily appreciated from the following description of the embodiments, taken in conjunction with the accompanying drawings of which:

fig. 1 is an exploded schematic view of an electret microphone according to an embodiment of the present invention;

fig. 2 is an exploded schematic view of an electret microphone according to another embodiment of the present invention;

fig. 3 is an exploded schematic view of an electret microphone according to another embodiment of the present invention;

fig. 4 is an exploded schematic view of an electret microphone according to another embodiment of the present invention;

fig. 5 is an exploded schematic view of an electret microphone according to another embodiment of the present invention;

fig. 6 is a schematic cross-sectional view of an electret microphone according to another embodiment of the present invention.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are exemplary only for the purpose of explaining the present invention, and should not be construed as limiting the present invention.

In the description of the present invention, if there are first and second descriptions for distinguishing technical features, they are not to be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features or implicitly indicating the precedence of the indicated technical features.

In the description of the present invention, unless there is an explicit limitation, the words such as setting, installation, connection, etc. should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meanings of the above words in combination with the specific contents of the technical solution.

The electret microphone of the present invention will be described in detail with reference to the accompanying drawings.

Referring to fig. 1, an embodiment of the present invention provides an electret microphone including a case 100, an acousto-electric conversion module 200, and a field effect transistor 300. The casing 100 is used for accommodating the acoustic-electric conversion module 200 and the field effect transistor 300, and the casing 100 protects the acoustic-electric conversion module 200 and the field effect transistor 300. The sound-electricity conversion module 200 is disposed in the casing 100, a sound inlet 110 is disposed on the casing 100, sound waves enter the inside of the casing 100 through the sound inlet 110 and trigger the sound-electricity conversion module 200, and the sound-electricity conversion module 200 can respond to the sound waves and generate corresponding electrical signals. The acoustic-electric conversion module 200 is provided with a pole plate 210, the pole plate 210 is made of a conductive material, and the acoustic-electric conversion module 200 transmits an electric signal to the field effect transistor 300 through the pole plate 210. The fet 300 is disposed in the housing 100, and the fet 300 is configured to change an output impedance of the acoustic-electric conversion module 200, so that an electrical signal generated by the acoustic-electric conversion module 200 can be received by a lower-stage amplification circuit or a digital identification circuit. In this embodiment, the fet 300 is an in-line package, the fet 300 is provided with a gate pin 310, a source pin 320, and a drain pin 330, the gate pin 310 is folded around the body of the fet 300 and covers the top of the fet 300, when the electret microphone of this embodiment is assembled, the fet 300 is abutted against the acoustic-electric conversion module 200, so that the portion of the fet 300 covering the top of the fet 310 is abutted against the polar plate 210, and the gate pin 310 is directly connected to the polar plate 210, while the source pin 320 and the drain pin 330 protrude from the housing 100 and are used for connecting to a lower-level amplifier circuit or a digital identification circuit. In the present embodiment, there is no other transmission medium between the plate 210 and the fet 300, and the transmission distance is short, so that the transmission impedance between the plate 210 and the fet 300 can be reduced, and reflection and loss of useful signals can be reduced, thereby improving the interference resistance of the present embodiment. Install the mode that acoustoelectric conversion module 200 in shell 100 and field effect transistor 300 connect through the apical grafting, make the grid pin 310 of field effect transistor 300 and the polar plate 210 butt of acoustoelectric conversion module 200, need not the welding or connect through other connecting device, the connected mode is simple, easily installs, can save the material expense that is used for connecting, and is from this visible, the utility model discloses an electret microphone can reduction in production cost.

In addition, in this embodiment, the connection mode between the fet 300 and the sound-electricity conversion module 200 is not limited by the position of the sound inlet 110 on the housing 100 and the polarization mode of the sound-electricity conversion module 200, so this embodiment may be applied to a diaphragm electret microphone, a back-electrode electret microphone, a pressure-difference electret microphone, a pressure-intensity electret microphone, and a pressure-difference combination electret microphone.

Referring to fig. 2 and 3, another embodiment of the present invention provides an electret microphone, based on the above embodiments, the housing 100 includes a cylindrical cover 120 and a circular circuit board 130, the circuit board 130 is connected with an end of the cover 120 and forms a containing cavity together, and the fet 300 and the sound-to-electricity conversion module 200 are disposed in the containing cavity. A cylindrical support 400 is disposed between the acoustic-electric conversion module 200 and the circuit board 130, a side wall of the support 400 is connected to an inner wall of the cover 120, one surface of the support 400 is connected to the pole plate 210 of the acoustic-electric conversion module 200, the other surface of the support 400 is connected to the circuit board 130, and the support 400 plays a role of supporting the acoustic-electric conversion module 200. One side of the support 400 close to the sound-electricity conversion module 200 is provided with a fixing groove 410, the fixing groove 410 is arranged on the axis of the support 400, the field effect tube 300 is fixed in the fixing groove 410, the support 400 also plays a role in filling the gap between the circuit board 130 and the pole plate 210 and fixing the field effect tube 300, so that the field effect tube 300 in the shell 100 cannot shift, the grid pin 310 and the pole plate 210 can be stably connected, the electret microphone can be ensured to stably and reliably work, and the product quality is improved. When the device is installed, the sound-electricity conversion module 200 is placed into the cover 120, the support 400 fixed with the field effect tube 300 is placed into the cover 120, and finally the circuit board 130 is covered on the end part of the cover 120, so that the support 400 is attached to the pole plate 210. In the installation process, the support 400 supports the fet 300, so that the fet 300 can be prevented from swinging or tilting due to the extrusion of the plate 210 during installation, the gate pin 310 of the fet 300 can be stably and sufficiently connected to the plate 210, and the fet 300 can be easily installed between the circuit board 130 and the plate 210, thereby improving the production efficiency and reducing the production cost.

Further, a first drawing hole 420 is provided on the bracket 400, a second drawing hole 131 is provided on the circuit board 130, and the fixing groove 410 is communicated with the first drawing hole 420. When the fet 300 is fixed to the fixing groove 410, the source lead 320 and the drain lead 330 of the fet 300 pass through the first lead-out hole 420; when the support 400 and the fet 300 are covered by the circuit board 130 in the accommodating cavity formed by the circuit board 130 and the cover 120, the source lead 320 and the drain lead 330 of the fet 300 pass through the second lead-out hole 131 and protrude from one surface of the circuit board 130 away from the accommodating cavity. The source pin 320 and the drain pin 330 of the fet 300 can be led out of the accommodating cavity through the first lead-out hole 420 and the second lead-out hole 131, which facilitates the connection of the electret microphone of the present embodiment with a lower-level amplifying circuit or a digital identification circuit; by using the source lead 320 and the drain lead 330 of the fet 300 as a connection medium for connecting a lower-stage amplifier circuit or a digital identification circuit, the use of connection materials can be reduced, and the manufacturing cost of the electret microphone can be reduced.

Further, an annular accommodating groove 430 is formed in one face, close to the circuit board 130, of the support 400, the accommodating groove 430 is arranged around the circumferential direction of the fixing groove 410, a damping sheet 431 and a foam-rubber cushion 432 are arranged in the accommodating groove 430, the groove bottom of the accommodating groove 430 is abutted to one face of the damping sheet 431, one face, far away from the groove bottom of the accommodating groove 430, of the damping sheet 431 is abutted to one face of the foam-rubber cushion 432, and one face, far away from the damping sheet 431, of the foam-rubber cushion 432 is in contact with the circuit board 130. When the electret microphone is assembled, the circuit board 130 is combined with the cover body 120, the sponge pad 432 and the damping sheet 431 are packaged in the accommodating groove 430 by the circuit board 130, and the damping sheet 431 is reliably attached to the support 400 under the support of the sponge pad 432, so that the consistency of product quality can be ensured.

Referring to fig. 4, 5 and 6, another embodiment of the present invention provides an electret microphone including a case 100, an acoustic-electric conversion module 200, a field-effect tube 300, a support 400 and a shield tube 500. The acoustic-electric conversion module 200 is provided with the plate 210, and the field effect transistor 300 is provided with a gate pin 310, a source pin 320, and a drain pin 330. The housing 100 includes a cover 120 and a circuit board 130, the circuit board 130 is connected to an end of the cover 120 to form an accommodating cavity, the acoustic-electric conversion module 200, the fet 300 and the bracket 400 are disposed in the accommodating cavity, and the cover 120 is provided with a sound inlet 110. The bracket 400 is disposed between the acoustic-electric conversion module 200 and the circuit board 130, a side wall of the bracket 400 is connected to an inner wall of the cover 120, one surface of the bracket 400 is connected to the pole plate 210 of the acoustic-electric conversion module 200, and the other surface of the bracket 400 is connected to the circuit board 130. A fixing groove 410 is formed on one surface of the bracket 400 close to the pole plate 210, the fixing groove 410 is formed on the axis of the bracket 400, the fet 300 is fixed in the fixing groove 410, the gate pin 310 of the fet 300 abuts against the pole plate 210 of the acoustic-electric conversion module 200, and the source pin 320 and the drain pin 330 of the fet 300 pass through the first lead-out hole 420 of the bracket 400 and the second lead-out hole 131 of the circuit board 130 and protrude from one surface of the circuit board 130 away from the bracket 400. A receiving groove 430 is formed at a side of the bracket 400 adjacent to the circuit board 130, and a damping sheet 431, a foam pad 432 and a shielding tube 500 are disposed in the receiving groove 430.

The shielding cylinder 500 is connected to a groove wall of the receiving groove 430 and is disposed around a circumference of the fixing groove 410, so that the field effect transistor 300 is enclosed inside the shielding cylinder 500. When the electret microphone of the present embodiment is packaged, the circuit board 130 is connected to the end of the cover 120, and the end of the shielding cylinder 500 is attached to and electrically connected to the first conductor 132, so that the shielding cylinder 500 is electrically connected to the ground wire of the circuit board 130. The fet 300 is disposed in the electromagnetic shielding compartment formed by the shielding cylinder 500 and the circuit board 130, and interference of an external electromagnetic field to the fet 300 can be reduced, so that the intrinsic noise of the present embodiment is reduced, and the signal-to-noise ratio and the interference resistance of the present embodiment are further improved.

Further, in this embodiment, the cover 120 is made of a conductive material, a second annular conductor 133 made of a copper foil exposed on the circuit board 130 is disposed on a surface of the circuit board 130 away from the bracket 400, the second conductor 133 is electrically connected to the ground line of the circuit board 130, and when the electret microphone of this embodiment is packaged, the end of the cover 120 is attached to and electrically connected to the second conductor 133 on the circuit board 130, so that the cover 120 is electrically connected to the ground line of the circuit board 130. By connecting the cover body 120 with the ground wire of the circuit board 130 in this embodiment, the interference of the external electromagnetic field to the acousto-electric conversion module 200 and the field effect transistor 300 in the accommodating cavity can be reduced, and the anti-interference capability of this embodiment is further improved.

It should be noted that the first conductor 132 and the second conductor 133 may be copper foils exposed on the circuit board 130, or may also be connection units with conductive performance, such as elastic pieces, clips, conductive foam, sockets or conductive grooves, etc. which are welded on the circuit board 130 and are made of conductive materials.

Further, the acoustic-electric conversion module 200 is also provided with a diaphragm 220 and a gasket 230. The edge of the diaphragm 220 is provided with a tension membrane ring 221 arranged along the circumference of the diaphragm 220, the tension membrane ring 221 is made of a conductive material, and the tension membrane ring 221 is connected with the cover body 120. The gasket 230 is disposed between the diaphragm 220 and the pole plate 210, one surface of the gasket 230 is connected to the tension ring 221, and the other surface of the gasket 230 is connected to the pole plate 210. The vibrating diaphragm 220 and the pole plate 210 form a transduction capacitor with constant charge and changeable capacitance, when the vibrating diaphragm 220 is vibrated by sound waves, the capacitance of the transduction capacitor changes, and the electric field between the vibrating diaphragm 220 and the pole plate 210 changes, so that alternating voltage changing along with the change of the sound waves is generated, and transduction is realized. The electric signal that produces on polar plate 210 directly transmits to field effect tube 300 through grid pin 310, and the electric signal that vibrating diaphragm 220 produced transmits to circuit board 130 through the cover body 120, therefore it is visible, the utility model discloses an electret microphone simple structure can reduce connecting material's use, reduction in production cost effectively.

Further, the source pin 320 is electrically connected to a ground line of the circuit board 130. The alternating voltage generated between the diaphragm 220 and the pole plate 210 is transmitted to the fet 300 through the gate pin 310, the cover 120 and the circuit board 130, and the acoustic-electric conversion module 200 performs impedance transformation through the fet 300. When the electret microphone of this embodiment is used to form a sound collection circuit, the ground of the lower stage amplifier or digital identification circuit is connected to the source pin 320 protruding from the housing 100, the drain pin 330 protruding from the housing 100 is connected to the power supply and the external resistor 610, and the dc blocking capacitor 620 is connected between the drain pin 330 and the input terminal of the lower stage amplifier or digital identification circuit.

The electret microphone of the present invention has been described in detail with reference to the drawings and the pressure-difference combined acoustic structure as an example, but the present invention is not limited to the above-described examples, and various changes can be made without departing from the spirit of the present invention within the knowledge range of those skilled in the art.

Claims (10)

1. An electret microphone comprising:

a housing;

the sound-electricity conversion module is arranged in the shell and is provided with a polar plate;

the field effect transistor is arranged in the shell and provided with a grid pin, and the grid pin is directly connected with the polar plate.

2. The electret microphone of claim 1 further comprising a holder, wherein the holder is disposed in the housing, wherein the holder has a retaining groove, and wherein the fet is disposed in the retaining groove.

3. The electret microphone of claim 2 further comprising a shield cylinder connected to the holder, the shield cylinder being disposed around a circumference of the fixing groove.

4. The electret microphone of claim 3, wherein the housing comprises a housing and a circuit board, wherein the circuit board is connected to the housing to form a receiving cavity, the holder and the acousto-electric conversion module are disposed in the receiving cavity, and the shielding cylinder and the acousto-electric conversion module are electrically connected to the circuit board.

5. The electret microphone of claim 4 wherein a first conductor is disposed on the circuit board, wherein the first conductor is electrically connected to a ground of the circuit board, and wherein the shield sleeve is connected to the first conductor.

6. The electret microphone of claim 4 wherein a second conductor is disposed on the circuit board, wherein the second conductor is electrically connected to a ground of the circuit board, and wherein the cover is connected to the second conductor.

7. The electret microphone of claim 4, wherein the holder has a first lead-out hole, the circuit board has a second lead-out hole, the fixing groove is connected to the first lead-out hole, the fet further has a source pin and a drain pin, and the source pin and the drain pin are inserted into the first lead-out hole and the second lead-out hole.

8. The electret microphone of claim 7 wherein the source lead is electrically connected to a ground of the circuit board.

9. The electret microphone of claim 4, wherein the acousto-electric conversion module further comprises a diaphragm and a gasket, the pole plate is connected to the bracket, the gasket is disposed between the diaphragm and the pole plate, the gasket is connected to the diaphragm and the pole plate, and the diaphragm is electrically connected to the cover.

10. The electret microphone of claim 4 wherein the holder is provided with a receiving groove, the receiving groove is arranged around the circumference of the fixing groove, a damping fin and a foam rubber pad are arranged in the receiving groove, and the bottom of the receiving groove, the damping fin, the foam rubber pad and the circuit board are connected in sequence.

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