KR100769696B1 - Condenser microphone - Google Patents

Abstract

A condenser microphone is provided to obtain the original characteristics of the condenser microphone by removing a heating process for soldering an F-PCB on a PCB(Printed Circuit Board) to prevent the deterioration of components. A condenser microphone includes a plate case(10), a spacer(13), a diaphragm(15), a base(14), a connecting ring(16), an FET(Field Effect Transistor)(20), and a PCB(17). The plate case(10) has a shape of a vessel which receives a plurality of components, has a sound wave inlet perforated on the horizontal surface, and a film is attached or coated on the inner surface. The spacer(13) is placed at the lower part of the film attached on the plate case(10), and maintains the air gap between the diaphragm(15) and the film for vibrating the diaphragm(15) by sound pressure. The diaphragm(15) is placed at the lower part of the spacer(13) by being attached at the upper end of a vibration plate, and has a film metal polar plate with the electric charge cumulated at the front surface vibrated by the sound pressure inputted through the sound wave inlet of the plate case(10). The base(14) is placed at the lower end of the spacer(13), and prevents the movement of each unit and supports each unit to maintain the insulation between the plate case(10) and the diaphragm(15), and the plate case(10) and the connecting ring(16). The connecting ring(16) is placed inside the base(14) and at the lower end of the vibration plate, and connects the FET(20) and the diaphragm(15). The FET(20) amplifies and converts the change of electric charge to an electric signal according to the change of capacitance between the diaphragm(15) and the film. The PCB(17) has patterns formed on the upper and lower surfaces where the amplification circuit including the FET(20), the plate case(10), and the connecting ring(16) are electrically connected, and has a connection pad for electrically connecting with the outside.

Description

Ultra-thin condenser microphone {Condenser microphone}

1 is an exploded perspective view of a conventional condenser microphone.

2 is a cross-sectional view of a conventional condenser microphone.

3 is an exploded perspective view of an ultra-thin condenser microphone according to the present invention.

FIG. 4 is a bottom perspective view of the printed circuit board shown in FIG. 3.

5 is a cross-sectional view of an ultra-thin condenser microphone according to the present invention.

-Explanation of symbols for the main parts of the drawings

10: plate case 11: sound wave inlet

12 filter 13 spacer

14 base 15 diaphragm

16: connection ring 17: printed circuit board

18a, 18b: Connection pads 19a, 19b: Pattern

20: FET 21: incision groove

22: film 23: extension part

The present invention relates to an ultra-thin condenser microphone. In particular, the present invention provides a printed circuit board comprising a FET and an amplification circuit for converting and amplifying a change in capacitance into an electrical signal, and an F-PCB for electrically connecting the FET and amplification circuit configured in the printed circuit board to the outside. The present invention relates to an ultra-thin condenser microphone that can be combined to integrally reduce the assembly process and reduce the thickness of the condenser microphone.

In general, a condenser microphone is a microphone using a change in capacitance of a parallel plate capacitor, with one fixed electrode and the other as a conductive diaphragm electrode. The voltage is applied, and the voltage generated when the capacitance is changed at the same time the electrode spacing is changed by the negative pressure is obtained as a voice signal.

The frequency characteristics are almost flat up to 30,000 Hz, high fidelity microphones, but their output is small, and has been widely applied to mobile communication terminals such as mobile phones in recent years.

Looking at the theory and principle of operation of the condenser microphone, the so-called internal components of the condenser microphone are very precise and sensitive to external electric noise, so that the sound wave is sufficiently protected from dust and foreign matter penetration and electric noise. The inlet is laminated and sealed in a metal case formed.

When sound waves are applied to the film metal diaphragm (Diaphragm) through the sound wave inlet, when the diaphragm vibrates, a distance change with the fixed plate (Polar Plate or Back Plate), that is, a distance change due to sound waves, occurs. Analysis can understand changes in capacitance.

In general, condenser microphones are used in combination with FETs, which are impedance conversion elements, in order to match the input impedance required by the amplifier because they have low capacitance and high electrical impedance and thus cannot be used in direct connection with a general amplifier.

Here, the FET is a field effect transistor, which is an active device composed of three terminals of a source, a gate, and a drain, and a basic operation circuit of an electrostatic condenser microphone system (ECMs) by changing the current value flowing between the drain and the source as the potential of the gate changes. It can be configured to obtain an electrical signal according to the sound waves.

Condenser microphones require a few hundred volts of external DC power supply with a positive polarity voltage, but ECMs are nonpolar condenser microphones. By accumulating, the external power supply is omitted.

Conventional condenser microphones, which can be used by being mounted on a microphone, a telephone, a tape record, or the like, are mounted on the plate case 102 and the plate case 102 on which the sound wave inlets 101 are perforated, as shown in FIGS. 1 and 2. It is located through the sound wave inlet 101 and the filter 103 to prevent inflow of moisture and foreign matter into the plate case 102, and is located inside the plate case 102 and through the sound wave inlet 101 The diaphragm plate 104 which maintains a space inside the plate case 102 to induce the vibration of the introduced sound, and is located at the lower end of the diaphragm plate 104 to vibrate by the sound introduced through the sound wave inlet 101 A diaphragm 105, a spacer 106 positioned at the lower end of the diaphragm 105 to maintain a vacuum to transmit negative vibrations, and a spacer 106 positioned at the lower end of the spacer 106. A base 107 which prevents and supports and prevents deformation of the overall shape, and is disposed inside the base 107 and maintained in a vacuum state at a predetermined interval from the diaphragm 105 by a spacer 106 and vibrating the diaphragm 105. A fixed electrode 108 for detecting a capacitance changed according to the connection, and a connection ring 109 located in the base 107 and at the bottom of the fixed electrode 108 to connect the gate of the matching FET and the fixed electrode 108. And a printed circuit board (110) having a circuit wired with a conductive material, and a FET (111) bonded to the printed circuit board (110) to amplify and convert a potential change caused by a change in capacitance into an electric signal. .

In particular, the bottom surface of the printed circuit board 110 is soldered to the F-PCB 112 that electrically connects the FET 111 and the amplification circuit and the like configured in the printed circuit board 110 with the outside.

In the conventional condenser microphone as described above, the diaphragm plate, the diaphragm, the spacer, the base, the fixed electrode, the connection ring, and the printed circuit board have to be soldered to the printed circuit board after the F-PCB is assembled. This lengthens the number of components in the plate case, so that there is a problem that the thickness of the condenser microphone becomes thick.

In addition, since high heat is applied in the process of soldering an F-PCB to a printed circuit board, characteristics of the FETs and amplification circuits formed on the printed circuit board may change, or internal components such as a vibration plate or a spacer may be deformed.

The present invention for solving the above-described drawbacks is to provide a printed circuit board comprising a FET and an amplification circuit for converting and amplifying a change in capacitance into an electrical signal, and the FET and amplifying circuit configured in the printed circuit board are external. The purpose is to reduce the assembly process and reduce the thickness of the condenser microphone by integrally combining the F-PCB, which is electrically connected to the F-PCB.

In addition, the present invention is to eliminate the process of applying heat to solder the F-PCB to the printed circuit board, so that components such as FET and amplification circuit is not deteriorated to obtain the unique characteristics of the condenser microphone. have.

Ultra-thin condenser microphone according to the present invention for achieving the above object is a container shape that can accommodate a plurality of components, the sound wave inlet is perforated in the horizontal plane and the charge is accumulated on one surface of the upper surface of the role of the fixed electrode A plate case having a film attached or coated by a spray method; A spacer positioned at a lower end of the film attached to the plate case to maintain an air gap between the diaphragm and the film for vibration of the diaphragm by sound pressure; A diaphragm that is attached to the upper end of the diaphragm plate and is formed on a lower end of the spacer and is formed of a film metal electrode plate in which charge is accumulated on the front surface vibrated by the sound pressure introduced through the sound wave inlet of the plate case; A base of an insulating material positioned under the spacer and supporting each part while preventing the flow of each part so that the plate case and the diaphragm and the plate case and the connection ring are insulated; A connection ring located inside the base and below the diaphragm plate of the diaphragm to connect the matching FET and the diaphragm; A FET for amplifying and converting a potential change according to a change in capacitance between the diaphragm and the film due to vibration of the diaphragm into an electrical signal; And a printed circuit board having an amplification circuit including the FET, a plate case, and a connection ring electrically connected to patterns formed on upper and lower surfaces thereof, and connecting pads for electrical connection to the outside in an extension extending on one side. It is characterized by including.

In the present invention, the pattern is preferably formed on the upper or lower surface, or the upper and lower surfaces of the printed circuit board.

In addition, in the present invention, the connection pad is preferably formed on the upper surface or the lower surface, or the upper and lower surfaces of the printed circuit board.

In the present invention, it is preferable that the patterns or connection pads formed on the upper and lower surfaces of the printed circuit board are electrically connected to each other.

In addition, in the present invention, it is preferable that a cutting groove for accommodating an extension of the printed circuit board is formed at one side of the plate case.

Hereinafter, the present invention will be described in detail.

The ultra-thin condenser microphone according to the present invention is bent inward to the end of the plate case in the state that the spacer, the base, the diaphragm, the connection ring and the printed circuit board, etc. in the plate case having a plurality of sound wave inlet in order to the above components They have a fixed structure.

On the inner surface of the plate case is attached a film having a thickness of about 20 ~ 30 ㎛ to replace the fixed electrode, the film is a charge is accumulated on one surface to perform the function of the fixed electrode. In addition, a filter is attached to the upper portion of the plate case to block various foreign substances from entering the plate case through the sound wave inlet.

3 to 5 show the ultra-thin condenser microphone according to the present invention, wherein the plate case 10 having a plurality of sound wave inlets 11 perforated in a horizontal plane is mounted on an electronic product such as a mobile phone or a PDA. It has a horizontal cross section of circular or elliptical shape so that it can effectively utilize the internal space of electronic products while maintaining (rising). A conductive material such as AL or brass soft may be used as the material of the plate case 10 having the container shape, and Ni of 2 to 3 μm and Au of 0.02 to 0.04 μm are sequentially formed on the surface of the plate case 10. It can be plated with.

In addition, the horizontal cross sections of the spacer 13, the base 14, the diaphragm 15, the coupling ring 16, and the printed circuit board 17 embedded in the plate case 10 may also be formed by the horizontal cross section of the plate case 10. It has the same shape and their diameter is equal to or smaller than the inner diameter of the plate case 10 so as to be embedded in the plate case 10.

And the inner surface of the plate case 10 is a film 22 having a thickness of about 20 ~ 30 ㎛ to replace the conventional fixed electrode is attached or coated by a spray method, the film 22 is a conventional Like the fixed electrode, charges are accumulated on one surface to perform the function of the fixed electrode. A filter 12 is attached to the upper portion of the plate case 10 to block various foreign substances from entering the plate case 10 through the sound wave inlet 11. In addition, at one end of the plate case 10, a cutout groove 21 for drawing out the extension 23 of the plate-shaped printed circuit board 17 out of the plate case 10 when the printed circuit board 17 is coupled to the printed circuit board 17. This is incision.

The spacer 13 positioned at the bottom of the plate case 10 is made of an insulating material such as a polyester film, and the diaphragm 15 and the film 22 for vibration of the diaphragm 15 by sound pressure. It keeps the air gap between them. Of course, the center has an empty space to secure a space for vibration of the diaphragm 15.

The diaphragm 15 is attached to the lower end of the spacer 13 is attached to the diaphragm plate, where the diaphragm plate is made of a metal material such as phosphor bronze, Ni may be plated on the surface of about 2 to 3 ㎛.

The diaphragm 15 vibrates by the sound pressure flowing through the sound wave inlet 11, and the diaphragm 15, which has accumulated charges on one surface, is attached to the ring-shaped diaphragm plate, so that the diaphragm 15 is embedded in the plate case 10. In the process of the thin plate diaphragm 15 is not deformed or damaged.

In other words, the diaphragm plate inserted into the plate case 10 while being integrally attached to the diaphragm 15 maintains a space inside the plate case 10 to induce vibration by the sound pressure introduced through the sound wave inlet 11. It serves to hold the outer periphery of the diaphragm 15 so as to maintain a flat state of the diaphragm 15. In addition, the diaphragm plate also serves to electrically connect the diaphragm 15 to the connection ring 16.

As the material of the diaphragm 15, a film metal electrode plate, that is, an Au-PET film or the like may be used.

Accordingly, the diaphragm 15 and the fixed electrode film 22 are disposed to face each other with a predetermined gap therebetween so that the diaphragm 15 and the fixed electrode have the same structure as a conventional capacitor.

The connecting ring 16 and the printed circuit board 17 positioned at the lower end of the diaphragm 15, ie, the diaphragm plate attached to the diaphragm 15, are separated by an end of the plate case 18, which is bent inwardly. Together with the base 14, the diaphragm 15, and the like, are maintained in the plate case 10. In particular, since the extension 23 of the printed circuit board 17 is positioned in the cutout groove 21 of the plate case 10, the printed circuit board 17 may maintain a horizontal state in the plate case 10. .

Here, the donut-shaped base 14 formed of an insulating material is disposed in the plate case 10 to insulate the diaphragm 15 and the connection ring 16 from being electrically connected to the plate case 10. . In addition, the connecting ring 16 made of a metallic material such as brass may be plated with Ni having a thickness of 2 to 3 μm and Au having a thickness of 0.02 to 0.04 μm on the surface thereof, which is used to match the FET and the diaphragm 15 not shown. Electrically connected.

An amplification circuit including an FET 20 for converting and amplifying a change in capacitance into an electric signal on the upper portion of the printed circuit board 17 integrally formed so as to function as an existing printed circuit board and an F-PCB. The upper and lower surfaces of the printed circuit board 17 have patterns 19a and 19b for the electrical connection of the amplifying circuit including the FET 20 by conductive materials. An extension part 23 extending at one side of the 17 is provided with connection pads 18a and 18b for electrical connection with an amplifying circuit including the FET 20 and a PCB in an electronic product.

In particular, the pattern 19a and the connection pad 18a formed on the upper surface of the printed circuit board 17 need to be electrically connected to the pattern 19b and the connection pad 18b formed on the lower surface of the printed circuit board 17. These are electrically connected with each other.

Of course, the patterns 19a and 19b or the connection pads 18a and 18b may be formed only on one surface of the upper or lower surface of the printed circuit board 17.

Here, the FET 20 serves to amplify and convert a potential change caused by a change in capacitance between the diaphragm 15 and the film 22 due to the vibration of the diaphragm 15 into an electric signal.

The operation of the condenser microphone thus constructed will be described.

When the gap between the diaphragm 15 and the film 22 is changed while the diaphragm 15 vibrates due to the sound pressure flowing through the sound wave inlet 11 of the plate case 10, the diaphragm 16 and the film 22 are separated. Capacitance changes.

As a result, since the potential (potential) of the film 22 is changed corresponding to the negative pressure and input to the gate of the FET 20, the current flowing from the source of the FET 20 to the drain is amplified corresponding to the negative pressure.

In this way, the condenser microphone converts the sound pressure flowing through the sound wave inlet 11 into an electric signal and amplifies it.

Therefore, according to the present invention, a printed circuit board comprising a FET and an amplification circuit for converting and amplifying a change in capacitance into an electrical signal, and an F-electric circuit electrically connecting the FET and amplification circuit configured in the printed circuit board to the outside. Integrating the PCB integrally reduces the assembly process of the condenser microphone and reduces the thickness.

In addition, the present invention eliminates the process of applying heat to solder the F-PCB to the printed circuit board, so that components such as FETs and amplification circuits are not degraded, thereby obtaining the unique characteristics of the condenser microphone.

Although the present invention has been described in detail only with respect to the specific embodiments described, it will be apparent to those skilled in the art that various changes and modifications can be made within the spirit of the present invention, and such modifications and modifications belong to the appended claims. .

Claims (5)

A plate case in which a sound wave inlet is perforated in a horizontal plane and charges are accumulated in one surface on an inner surface of the container shape capable of accommodating a plurality of components to which a film serving as a fixed electrode is attached or coated by a spray method; A spacer positioned at a lower end of the film attached to the plate case to maintain an air gap between the diaphragm and the film for vibration of the diaphragm by sound pressure; A diaphragm that is attached to the upper end of the diaphragm plate and is formed on a lower end of the spacer and is formed of a film metal electrode plate in which charge is accumulated on the front surface vibrated by the sound pressure introduced through the sound wave inlet of the plate case; A base of an insulating material positioned under the spacer and supporting each part while preventing the flow of each part so that the plate case and the diaphragm and the plate case and the connection ring are insulated; A connection ring located inside the base and below the diaphragm plate of the diaphragm to connect the matching FET and the diaphragm; A FET for amplifying and converting a potential change according to a change in capacitance between the diaphragm and the film due to vibration of the diaphragm into an electrical signal; And A printed circuit board having an amplification circuit including the FET, a plate case, and a connection ring electrically connected to patterns formed on upper and lower surfaces thereof, and a connection pad for electrically connecting an external portion to an extension extending on one side; Ultra-thin condenser microphone comprising a. The method of claim 1, The pattern is ultra-thin condenser microphone, characterized in that formed on the upper or lower surface or the upper and lower surfaces of the printed circuit board. The method of claim 1, And the connection pads are formed on an upper surface, a lower surface, or an upper surface and a lower surface of the printed circuit board. The method of claim 1, An ultra-thin condenser microphone, characterized in that the pattern or connection pads formed on the upper and lower surfaces of the printed circuit board are electrically connected to each other. The method of claim 1, Ultrathin condenser microphone, characterized in that the incision groove which can accommodate the extension of the printed circuit board is formed on one side of the plate case.

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