KR20070105786A - Condenser microphone - Google Patents

Abstract

A condenser microphone is provided to reduce production cost and to decrease the total thickness of the condenser microphone, by simplifying the assembly process. According to a condenser microphone using capacitance variation of a parallel plate condenser, a vessel type metal case(110) is punctured with a sonic wave inflow hole(112) in the center and fixes internal components. A diaphragm(120) comprises a metal deposition film(125) vibrating according to the sonic wave as being stacked in the metal case and a diaphragm plate fixing the frame of the metal deposition film. A metallic connection ring(140) forms a bottom plane in parallel with the diaphragm, and has an electret film(125) accumulated with semi-permanent charges on the bottom plane. An insulation spacer(130) is inserted between the diaphragm and the connection ring, and maintains a constant gap between the diaphragm and the connection ring. A printed circuit board(150) is electrically connected to the metal case and the connection ring as being located on the uppermost top in the metal case, and comprises a field effect transistor for amplifying and converting potential variation according to the variation of capacitance between the electret film attached to the connection ring and the diaphragm due to the vibration of the diaphragm into an electrical signal.

Description

Condenser Microphone

1 is an exploded perspective view showing the structure of a conventional condenser microphone;

2 is a cross-sectional view showing a structure of a conventional condenser microphone;

3 is an exploded perspective view showing the structure of a condenser microphone according to the present invention;

4 is a cross-sectional view showing the structure of the condenser microphone according to the present invention,

5 is an exploded perspective view showing another embodiment of a condenser microphone according to the present invention;

6 is a cross-sectional view showing another embodiment of the capacitor microphone according to the present invention.

Explanation of symbols on main parts of the drawings

100, 200: condenser microphone

110, 210: Metal case

120, 220: diaphragm

122, 222: diaphragm plate

125: metal deposition film

145, 225: Elet Let Film

130, 230: spacer

140, 240: connecting ring

150, 250: printed circuit board

162, 262: FET (Field effect transistor)

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to condenser microphones, and more particularly, to condenser microphones that can be manufactured in an ultra-thin form by improving the assemblability by reducing the number of parts, reducing the cost, and reducing the size.

In general, a condenser microphone is a microphone using a change in capacitance of a parallel plate capacitor. The condenser microphone has a fixed electrode on one side and a conductive diaphragm as an electrode opposite to the fixed electrode on the other side. Through a resistor, a high DC voltage is applied. As a result, a change in capacitance between both electrodes is obtained as a voice signal, which is an electric signal, due to a change in electrode spacing due to sound pressure.

The frequency characteristic of the condenser microphone is almost flat up to 30 kHz, and is a high fidelity microphone, but its output is small, and recently, it has been widely applied to mobile communication terminals such as mobile phones, PDAs, and the like.

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 sound waves can be sufficiently protected from infiltration of dust or foreign matter and electric noise. The inlet is laminated and sealed in a metal case formed.

When sound wave is applied to the film metal diaphragm (Diaphragm) through the sound wave inlet, when the diaphragm vibrates, the distance change between the diaphragm and the fixed plate (Polar Plate or Back Plate), that is, the distance change due to sound waves, occurs. It can be converted electrically to grasp changes in capacitance.

In general, a condenser microphone has a small capacitance and a high electrical impedance, and thus cannot be directly connected to a general amplifier. Therefore, a condenser microphone is generally used in combination with an FET, which is an impedance conversion element, to match the input impedance required by the amplifier.

Here, the field effect transistor (FET) is an active element composed of three terminals of a source, a gate, and a drain as a field effect transistor. The electrostatic condenser microphone system is changed by changing the current value flowing between the drain and the source as the potential of the gate changes. By configuring basic operation circuit of), it is possible to obtain electrical signals according to sound waves.

Condenser microphones require a DC external supply of hundreds of volts at positive polarity voltage, but ECMs are a type of nonpolar condenser microphones that deposit metal on polymer films with excellent charge storage characteristics (hereinafter, "eletret films"). External supply power is omitted by using a diaphragm or by attaching a polymer film to a fixed electrode to accumulate charge.

The condenser microphone, which can be used by attaching it to a microphone, wired / wireless telephone, video cassette recorder, or digital camera, is provided with a case in which the sound wave inlet is perforated and dust, moisture, or foreign matter enters the inside of the case through the sound wave inlet. A filter to prevent the vibration, a diaphragm plate positioned inside the case and maintaining a space inside the case to induce vibration of sound introduced through the sound wave inlet, and a sound placed through the sound wave inlet located at the bottom of the diaphragm plate.

A vibrating diaphragm, a spacer positioned at the lower end of the diaphragm to maintain a predetermined interval to transmit negative vibration, a support positioned at the lower end of the spacer to prevent and support the flow of each part, and to prevent deformation of the overall shape; A fixed electrode positioned inside the support to maintain a vacuum at a predetermined interval from the diaphragm by a spacer and detecting capacitance changing according to the vibration of the diaphragm, and located at the bottom of the support and the fixed electrode, and a gate of the matching FET and the fixed electrode A connection ring for connecting the circuit board, a printed circuit board on which a circuit is wired with a conductive material, and a FET bonded on the printed circuit board to amplify and convert a potential change caused by a change in capacitance into an electric signal.

1 and 2 show a conventional condenser microphone, which includes a diaphragm plate 12, a diaphragm 13, a spacer 14, a fixed electrode 15, a support 17, in a metal case 11. The connection ring 18, the printed circuit board 19, and the like are sequentially embedded.

However, the condenser microphone insulates the metal case and the fixed electrode, and is provided with a support and a connection ring to electrically connect the fixed electrode and the printed circuit board. There was a problem that there is a limit to miniaturization, ultra-thin.

An object of the present invention is to provide a condenser microphone which reduces the number of parts of the condenser microphone, minimizes the thickness and simplifies the assembly process.

In addition, another object of the present invention is to provide a condenser microphone which can reduce the number of parts of the condenser microphone and simplify the assembly process so as to reduce the overall thickness of the condenser microphone and lower the production cost.

The present invention for achieving the above object is a sound wave inlet in the center, the container-shaped metal case for fixing the internal components; A diaphragm laminated on the inside of the metal case and comprising a diaphragm plate vibrating according to sound waves and a diaphragm plate fixing the edge of the metal deposition film; A connection ring formed of metal material having a bottom surface parallel to the diaphragm and having an eletret film having a semi-permanent charge amount accumulated thereon; A spacer made of an insulating material inserted between the diaphragm and the connection ring to maintain a constant gap between the diaphragm and the connection ring; And a potential change according to a change in capacitance between the diaphragm and the elet film attached to the coupling ring due to vibration of the diaphragm and electrically connected to the metal case and the connection ring at the top of the metal case. It provides a condenser microphone comprising a; printed circuit board having a field effect transistor for amplifying and converting into an electrical signal.

In addition, the present invention is a sound wave inlet hole in the center, the container-shaped metal case for fixing the internal components; A diaphragm laminated on the inner side of the metal case and composed of an vitreous plate vibrating according to sound waves and a vibrating plate for fixing an edge of the vitreous film; A connection ring formed of a metal material forming a bottom surface parallel to the diaphragm and having a bottom surface serving as a fixed electrode; An insulating material spacer inserted between the diaphragm and the connection ring to maintain a predetermined gap between the diaphragm and the connection ring; Located at the top of the metal case and electrically connected to the metal case and the connection ring, for amplifying and converting a potential change according to a change in capacitance between the diaphragm and the connection ring due to vibration of the diaphragm into an electrical signal. It provides a condenser microphone comprising a; printed circuit board having a field effect transistor.

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

3 is an exploded perspective view showing the structure of a condenser microphone according to the present invention, Figure 4 is a cross-sectional view showing a structure of the condenser microphone according to the present invention.

The present invention is to reduce the number of parts and to reduce the manufacturing cost by maintaining the number of parts while maintaining a certain level of quality, to eliminate the fixed electrode that was previously formed as a separate component, the connection ring of the fixed electrode It performs a role and performs insulation by using an insulating material such as ceramic on the outer circumferential surface of the connection ring (the surface in contact with the inner surface of the nibble case) that removes the base, which is an insulator inserted between the connection ring and the metal case. It is to reduce the cost of the product by significantly reducing the number.

As shown, the condenser microphone 100 according to the present invention is perforated with a sound wave inlet 112 in the center, and receives the components therein and electrically connects the diaphragm 120 and the printed circuit board 150. A cylindrical container-shaped metal case 110, a diaphragm 120 which is placed on the bottom of the metal case 110 and vibrates according to sound waves, and a bottom surface parallel to the diaphragm 120 is formed and the bottom thereof. An electret film 125 having a semi-permanent charge amount is attached to a surface thereof, and a metal ring connection ring 140 electrically connected to the printed circuit board 160, and a diaphragm 120 and a connection ring. The spacer 140 is made of an insulating material and is inserted between the diaphragm 120 and maintains a constant gap between the diaphragm 120 and the connection ring 140, and is located at the top of the metal case 110. ) And diaphragm 120, respectively And a field effect transistor 152 for amplifying and converting a potential change caused by a change in capacitance between the diaphragm 120 and the electret film 125 into an electric signal. It consists of a printed circuit board 150 provided.

The metal case 110 is made of a conductive material and has a cylindrical shape in which the sound wave inlet 112 is perforated. Basically, it serves to receive and fix the internal components, and is electrically connected to the diaphragm 120 and the printed circuit board 150 to electrically connect the diaphragm 120 and the printed circuit board 150. Do this. It is preferable to attach a separate nonwoven fabric 115 to the bottom surface of the sound wave inlet 112 of the metal case 110 to prevent foreign substances from being introduced into the metal case 110 and to protect the metal case. .

The diaphragm 120 is formed of a donut-shaped diaphragm plate 122 and a metal deposition film 125 flatly attached to the diaphragm plate 122. The metal deposition film 125 is formed by depositing a metal on the surface of a synthetic resin film such as PET, PTFE, FEP. As shown in the cross-sectional view of FIG. 4, the metal deposition film 125 has an edge fixed between the spacer 130 and the diaphragm plate 122 in a state in which the condenser microphone 100 is assembled, and the center portion is spaced above and below. Since it is vibrated by the sound waves transmitted through the sound wave inlet 112. The metal deposition film 125 is electrically connected to the printed circuit board 150 through the metal case 110.

The spacer 130 is made of an insulating material, and secures a gap between the metal deposition film 125 and the elet film 145 constituting the positive electrode plate of the parallel plate capacitor, and the films are not electrically connected. To act as an insulating layer.

The connection ring 140 according to the present invention plays a role of the conventional fixed electrode 15, the support 17, and the connection ring 18, thereby greatly contributing to the reduction in the number of parts. First, in order to perform a role as a fixed electrode, the connection ring 140 has a surface formed in parallel with the metal deposition film 125, and the electret film 145 in which semi-permanent charges are accumulated on the surface. Is attached. The electret film 145 is preferably attached with an adhesive. The conductive adhesive may be used for the conductive purpose, but the common adhesive may be used for the conductive adhesive. The adhesive film 145 thus bonded is electrically connected to the printed circuit board 150 via the connection ring 140. The electrical connection performance is improved by depositing and coating a metal such as nickel on one side of the electret film 145.

In addition, the connection ring 140 is coated with an insulating layer 145 on an outer circumferential surface that is a surface facing the inner surface of the metal case 110. This is because the connection ring 140 and the metal case 110 are connected to the printed circuit board, respectively, so that the connection ring 140 and the metal case 110 should not be energized with each other. Conventionally, a base made of a separate insulating material is disposed between the connection ring and the metal case for such insulation, whereas the present invention replaces the base by forming the insulating layer 145 on the outer circumferential surface of the connection ring 140. . The insulating layer 145 is formed by coating an insulating material such as ceramic or synthetic resin to insulate between the connection ring 140 and the metal case 110.

The printed circuit board 150 is stacked on the connection ring 140 and is electrically connected to the metal deposition film 125 and the elet film 145 in the respective paths as described above. The printed circuit board 150 includes a field effect transistor 152 such that the field effect transistor 152 amplifies a potential change caused by a change in capacitance between the films 125 and 145 by an electric signal. do.

Figure 4 is an exploded perspective view showing another embodiment of a condenser microphone according to the present invention, Figure 5 is a combined cross-sectional view showing another embodiment of the condenser microphone according to the present invention.

As shown, the condenser microphone 200 according to the present invention is perforated with a sound wave inlet 212 in the center, and receives the components therein and electrically connects the diaphragm 220 and the printed circuit board 250 A cylindrical container-shaped metal case 210, a diaphragm 220 placed at the bottom of the metal case 210 and vibrating according to sound waves, and a bottom surface parallel to the diaphragm 220 is formed and the bottom thereof. The surface serves as a fixed electrode and is inserted between the connection ring 240 made of a metal material electrically connected to the printed circuit board 250, and the diaphragm 220 and the connection ring 240 to the vibration plate 220. ) And a spacer 240 made of an insulating material to maintain a constant gap between the coupling ring 240 and the connection ring 240, and are electrically connected to the metal case 210 and the diaphragm 220 at the uppermost end of the metal case 210. Is generated by sound waves The printed circuit board 250 includes a field effect transistor 252 for amplifying and converting vibration into an electric signal by changing a potential change according to a change in capacitance between the diaphragm 220 and the elet film 225. .

This embodiment has the same configuration and effect as the previous embodiment and the metal case 210, spacer 230, printed circuit board 250, and has a difference in the diaphragm 220 and the connection ring 240. .

The diaphragm 220 according to the present embodiment is provided with an elet film 225 instead of a metal deposition film (125 in FIG. 3), and the connection ring 240 faces the elet film 225. Since the surface itself serves as a fixed electrode, a separate film is not attached.

Like the previous embodiment, the connection ring 240 forms an insulating layer 242 on the outer circumferential surface thereof and is insulated from the metal case 210.

As described above, the condenser microphone according to the present invention has the effect of reducing the number of parts of the component, such that the reduction of the number of components realizes cost reduction and ultra-miniaturization of the microphone due to the reduction of assembly labor Help in doing

The present invention has the effect of providing a condenser microphone that can reduce the number of parts of the condenser microphone, minimize the thickness and simplify the assembly process.

In addition, the present invention has the effect of reducing the number of parts of the condenser microphone and the assembly process is simplified to reduce the overall thickness of the condenser microphone and lower the production cost.

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 modifications and variations are possible within the spirit of the present invention, and such modifications and modifications belong to the appended claims. .

Claims (3)

In the condenser microphone using the capacitance change of the parallel plate capacitor, A sound wave inlet is perforated in the center, the container-shaped metal case for fixing the internal components; A diaphragm laminated on the inside of the metal case and comprising a diaphragm plate vibrating according to sound waves and a diaphragm plate fixing the edge of the metal deposition film; A connection ring formed of a metal material having a bottom surface parallel to the diaphragm and having an elettet film having a semi-permanent charge amount accumulated thereon; An insulating material spacer inserted between the diaphragm and the connection ring to maintain a predetermined gap between the diaphragm and the connection ring; And Located at the top of the metal case and electrically connected to the metal case and the connection ring, the potential change according to the change in capacitance between the diaphragm and the electret film attached to the connection ring due to the vibration of the diaphragm A condenser microphone comprising: a printed circuit board having a field effect transistor for amplifying and converting into a signal. In the condenser microphone using the capacitance change of the parallel plate capacitor, A sound wave inlet is perforated in the center, the container-shaped metal case for fixing the internal components; A diaphragm laminated on the inner side of the metal case and composed of an vitreous plate vibrating according to sound waves and a vibrating plate for fixing an edge of the vitreous film; A connection ring formed of a metal material forming a bottom surface parallel to the diaphragm and having a bottom surface serving as a fixed electrode; An insulating material spacer inserted between the diaphragm and the connection ring to maintain a predetermined gap between the diaphragm and the connection ring; And An electric field for amplifying and converting a potential change according to a change in capacitance between the diaphragm and the connection ring due to vibration of the diaphragm, and electrically connected to the metal case and the connection ring at the top of the metal case; A condenser microphone comprising: a printed circuit board having an effect transistor. The method according to claim 1 or 2, And an insulating layer between the metal case and the connection ring.

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