KR20020024122A - Capacitor microphone - Google Patents

Abstract

PURPOSE: A capacitor microphone is provided to considerably decrease a noise by howling and echo phenomenon and the wind by forming an important sound wave inflow path at a pressure portion of a metal case body and a PCB. CONSTITUTION: A PCB(32) is pressed for covering an opened surface of a metal case body(30), and a sound wave inflow path is formed in the pressure portion of the PCB(32) and a plurality of sound wave inflow holes(36) are formed in the pressure portion of the PCB(32). An FET(38) is mounted on the PCB(36) for generating an electric signal corresponding to a sound wave. A ring-type connector(42) is allocated in a forward direction of a double polar holder(40) allocated in an internal wall surface of the metal case body(30), and a sound wave passing hole(44a) extended from a sound wave inflow path formed at a pressure portion of the metal case body(30) and the PCB(32) is formed in the ring-type connector(42). A diaphragm(48) is allocated at a uniform interval with a backplate(44) allocated at an upper side of the ring-type connector(42) and provides a capacitance varied between the backplate(44) to the FET(38) according to a sound wave inputted through the sound wave inflow path and the sound wave inflow holes(36). A double polar chamber(50) is formed in the center of the diaphragm(48).

Description

Condenser Microphone {CAPACITOR MICROPHONE}

The present invention relates to a condenser microphone. More particularly, the present invention relates to a condenser microphone, which is applied to an audio device for speech processing or a communication device for communication of voice, and converts voice into an electrical signal.

As is well known, an audio device for voice processing or a communication device (eg, a general telephone or a mobile communication device) for voice communication is provided with a microphone for receiving a voice and converting it into an electrical signal.

1 is a view for explaining an outline of a general condenser microphone.

In the drawing, the case body 10 is formed of aluminum, and the sound wave inlet 10a is formed on one surface thereof, and is usually formed of aluminum to seal and compress the components of the corresponding condenser microphone to prevent foreign substances from being introduced from the outside, and also from the outside. The protective cap prevents the inflow of noise.

Diaphram, denoted by 12, is usually formed by vacuum evaporating Ni on PET or PPS film, and vibrating by sound waves while maintaining a small distance from the back plate, which will be described later. It will act to cause the change of.

The back plate indicated by 14 is manufactured by punching a panel in which a FEP film is adhered to an SUS plate with a press mold, and is usually charged at a high voltage of several KV to serve as a double plate, and the charging potential thereof is a corresponding capacitor. The sensitivity of the microphone is determined and the phenomenon is referred to as an 'electret'.

The polar ring indicated by 16 is manufactured by, for example, punching a SUS304 panel into a press mold, and is generally used for supporting the diaphragm 12.

The spacer 18 is interposed between the diaphragm 12 and the back plate 14 to serve as a gap body and an electrical insulator to maintain a constant gap therebetween, and is usually produced by punching a PET film into a press mold. do.

In addition, the ring-shaped connector indicated by 20 in FIG. 1 has a function of electrically connecting the gate of the field effect transistor (FET) to be described later with the back plate 14, and usually presses brass. Then it is plated with gold and manufactured.

The polarization holder (I.R ring) denoted by 22 is assembled with the back plate 12 and the ring-shaped connector 20 to act as a mechanical support and an insulator, and is preferably manufactured by injection molding of ABS material.

The FET, denoted 24, serves as an impedance converter that delivers a change signal to a subsequent amplifier (not shown), resulting in a change in electrical capacitance as a change in impedance.

The chip capacitor shown at 26 is connected between the source and the drain of the FET 24 to attenuate high frequency noise introduced from the outside.

In addition, the PCB indicated by 28 serves as a rear cover and an output terminal of the corresponding condenser microphone, and is composed of a contact type, a pin type, and a soldering type according to its use.

FIG. 2 shows an electrical equivalent circuit diagram of the condenser microphone shown in FIG. 1, and according to the action of the general condenser microphone shown in FIGS. 1 and 2, the sound wave inlet 10a formed on the front end surface of the metallic case body 10. When sound waves are transmitted to the diaphragm 12 and the diaphragm 12 is displaced, the capacitance changes between the diaphragm 12 and the back plate 14 forming a condenser.

The output of the capacitor, which is variable based on the action of the diaphragm 12, is amplified by impedance conversion by the FET 24, and the amplified output is defined on the PCB 28. ) And ground terminal (G).

However, in the general condenser microphone shown in Figs. 1 and 2, since the sound wave inflow hole is formed upward, when the condenser microphone is applied to, for example, the mobile communication terminal, the voice received by the mobile communication terminal and output by the receiver It flows into the condenser microphone, and eventually a howling or an echo phenomenon easily occurs.

In addition, in the general condenser microphone, the frequency response is uniform because it is difficult to secure an optimal volume as the FET 24 is positioned in the polarization chamber defined between the back plate 14 and the PCB 28. It is difficult to expect characteristics.

In addition, when the metallic case body 10 and the PCB 28 are joined by a crimping process, an unnecessary gap is easily formed between the metallic case body 10 and the PCB 28, and there is a gap between the metallic case body 10 and the PCB 28. This often results in poor low frequency attenuation characteristics.

Accordingly, the present invention has been made in view of the above-described state of the art, and in addition to forming a sound wave inlet in the PCB on which the FET is mounted, a sound wave inlet is also formed in the crimped portion of the PCB and the metallic case, for example, a mobile communication terminal. Even if it is applied to the circuit, it prevents howling, echo phenomenon or noise caused by wind while securing a uniform volume response of the double polarization chamber to obtain uniform frequency response characteristics, and the gap during the crimping process of the PCB and the metallic case. It is an object of the present invention to provide a condenser microphone designed to improve the low frequency attenuation characteristics caused by generation.

In order to achieve the above object, according to a preferred embodiment of the present invention, one surface is compressed to cover an open surface of an unopened metallic case body while a sound wave inflow path is formed at the crimped portion and a plurality of sound wave inflow holes are formed. With PCB; A FET mounted on the PCB to generate an electrical signal corresponding to sound waves; A ring-shaped connector disposed in front of the polarization holder disposed on the inner wall surface of the metallic case body and having a sound wave passage formed therein extending to the acoustic wave inflow path formed at the crimping portion of the metallic case body and the PCB; The capacitively arranged between the back plate disposed at an upper side of the ring-shaped connector at regular intervals and oscillated by the sound wave inflow path and the sound wave introduced through the sound wave inlet hole may vary the capacitance between the back plate and the back plate. A condenser microphone is provided which is provided in the FET and has a diaphragm formed at the center thereof to form a bipolar chamber.

According to the present invention, a plurality of cutouts defining the sound wave inlet is formed at the outer circumferential end of the PCB, and the rear of the cutout is tapered to a certain depth on the upper and lower surfaces so that the sound wave inflow becomes smooth.

In addition, the sound wave passage formed in the ring-shaped connector is formed so as to communicate with the sound wave inlet formed between the metallic case body and the PCB.

In the condenser microphone according to the present invention having the above-described configuration, a sound wave inlet for forming a sound wave path is formed at the crimping portion of the metallic case body and the PCB, and a plurality of sound wave inlet holes are formed on the PCB to directly absorb sound waves. On the other hand, howling caused by external sound and / or adverse effects caused by echo or wind are suppressed.

In addition, as the FET is installed on the lower side of the metallic case body, a uniform volume response chamber is formed inside the diaphragm to ensure uniform frequency response characteristics, and the acoustic wave inlet is formed on the metallic case body and the crimping part of the PCB. The adverse effects caused by gaps during the crimping process of the metallic case and the PCB are also excluded.

1 is a view for explaining the outline of a conventional capacitor microphone (Capacitor Microphone),

2 is an electrical equivalent circuit diagram of the condenser microphone shown in FIG. 1;

3 is a cross-sectional structure diagram of a condenser microphone according to a preferred embodiment of the present invention;

4A is a view showing the structure of a metallic case body constituting the condenser microphone shown in FIG. 3;

4B is a view for explaining the structure of a PCB constituting the condenser microphone shown in FIG. 3;

4C is a view for explaining the structure of the ring-shaped connector constituting the condenser microphone shown in FIG.

5a and 5b is a reference diagram for explaining the sound wave influx of the condenser microphone according to the present invention,

FIG. 5C is a reference diagram for explaining a sound wave inflow action of the general condenser microphone shown in FIG. 1.

* Description of the symbols for the main parts of the drawings *

10: metallic casing, 12: diaphragm,

14: back plate, 20: ring-shaped connector,

22: polarization holder, 24: FET,

28: PCB, 30: metallic case body,

32: PCB, 34: sound wave inlet,

36: sound wave inlet, 38: FET,

40: polarization holder, 42: ring-shaped connector,

44: back plate, 48: diaphragm.

Hereinafter, with reference to the accompanying drawings, the present invention will be described in detail.

3 is a cross-sectional structure diagram of a condenser microphone according to a preferred embodiment of the present invention.

According to the condenser microphone of the present invention shown in FIG. 3, a sound wave inlet 34 is defined at a crimped portion of the metallic case body 30 and the PCB 32 made of, for example, aluminum, so that the sound wave inlet 34 Inflow (34a in FIG. 3) is possible.

In addition, at least one sound wave inlet hole 36 is formed in the PCB 32 to allow the inflow of sound waves 36a similarly to the sound wave inlet 34, and the FET 38 on the PCB 32. Is mounted.

Here, an air hole (see 30a in FIG. 4A) is formed on an inner surface of the case body 30 to discharge air therein.

Preferably, according to the present invention, a plurality of cutouts 32a are formed at predetermined positions so that the sound wave inlet 34 is formed on the outer periphery of the PCB 32 even when the metallic case body 30 is compressed. Is formed (see FIG. 4B).

Here, more advantageously, the upper portion and the lower surface of the rear portion in which the plurality of cutouts 32a are formed on the PCB 32 are tapered at a constant depth in order to provide better sound waves (FIG. 4B). Reference).

In addition, a polarization holder 40 is disposed on an inner wall surface of the metallic case body 30, and a ring-shaped connector 42 is disposed in front of the polarization holder 40, and the ring-shaped connector 42 is In the form illustrated in FIG. 4C, sound wave passing holes 42a are formed at regular intervals at a lower end thereof.

In addition, according to the present invention, a back plate 44 having a sound wave passing hole 44a is generally disposed on the ring-shaped connector 42, and an outer end of the back plate 44 is disposed on the ring holder 42. 40).

In addition, the diaphragm 48 is disposed on the bipolar holder 40 via a spacer 46.

Here, the overall operation and function of the condenser microphone according to the present invention shown in Figure 3 is made similar to the general condenser microphone described with reference to FIG.

However, in the case of the general metallic case 10 shown in FIG. 1, since a plurality of sound wave inflow holes for inflow of sound waves are formed on one surface thereof and receive sound waves directly, for example, a receiver when actually applied to a mobile communication terminal. The voice from the stream is affected by howling or echo and / or wind noise, but according to the present invention shown in FIG. 3, one surface of the metallic case body 30 maintains a closed shape, for example. In fact, when applied to a mobile communication terminal, the voice from the receiver is introduced, and the influence of howling, echo phenomenon and / or wind noise is remarkably improved.

5A and 5B, the condenser microphone 64 according to the present invention is mounted on the upper portion (FIG. 5A) or the lower portion (FIG. 5B) of the main substrate 62 of the mobile communication terminal 60. Since the sound wave is not directly introduced into the condenser microphone 64 but the sound wave is introduced from the lateral direction, the sound absorbing region 64a of the condenser microphone 64 and the receiver of the portable communication terminal 60 The output area 66a of 66) is formed differently so that howling and echo are eliminated, and wind noise is remarkably improved.

On the other hand, referring to FIG. 5C, in the case of the general condenser microphone shown in FIG. 1, the condenser microphone 74 corresponding to the condenser microphone 74 corresponding to the main board 72 of the mobile communication terminal 70 is mounted. ) Overlaps with the sound output area 76a of the receiver 76 of the mobile communication terminal 70 to produce howling and / or echo phenomena. It is easy to inflow.

In addition, according to the present invention, the volume of the polarization chamber 50 formed in the vicinity of the diaphragm 48 is not occupied by the FET 38 unlike the structure of the condenser microphone shown in FIG. Is secured, and a uniform frequency response characteristic is obtained from such a constant volume of polarization chamber 50.

As described above, according to the condenser microphone according to the present invention, since the main sound wave inflow path is formed at the crimping portion of the metallic case body and the PCB, the sound output is compared with that of the general condenser microphone in which the sound wave inflow path is formed on one surface of the metal case body. Howling and echo phenomena and wind noise caused by the adjacent arrangement of circles (e.g. receivers when applied to portable communication terminals) are significantly improved.

In addition, since the FET is disposed close to the sound wave inflow path inside the metallic case body, and the polarization chamber is separately assumed on the upper side of the FET, the polarization chamber can be designed to have a constant volume, thereby providing a uniform frequency response characteristic. Can be secured.

Furthermore, according to the present invention, since the sound wave inflow path is designed on the pressing part of the metallic case body and the PCB, the burden on the pressing process of the metallic case body and the PCB is reduced.

Claims (3)

A metallic case body whose one side is sealed and the opposite side is open; A PCB formed with a plurality of sound wave inflow paths and a plurality of sound wave inflow holes formed on the crimped portion while being pressed to cover the open surface of the metallic case; A FET mounted on the PCB to generate an electrical signal corresponding to sound waves; A ring-shaped connector disposed in front of the polarization holder disposed on the inner wall surface of the metallic case body and having a sound wave passage extending from the metallic case body and the acoustic wave inflow path formed at the crimping portion of the PCB; The capacitively arranged between the back plate disposed at an upper side of the ring-shaped connector at regular intervals and oscillated by the sound wave inflow path and the sound wave introduced through the sound wave inlet hole may vary the capacitance between the back plate and the back plate. And a diaphragm provided at the center of the FET and having a polarization chamber formed at the center thereof. The condenser microphone according to claim 1, wherein a plurality of cutouts defining the sound wave inlets are formed at an outer circumferential end of the PCB, and a rear surface of the cutouts is tapered at a constant depth on an upper surface and a lower surface. The condenser microphone according to claim 1, wherein the sonic wave passage formed in the ring-shaped connector is formed to communicate with the sonic wave inlet formed between the metallic case body and the PCB.